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1 /* coap_net.c -- CoAP context inteface
2  *
3  * Copyright (C) 2010--2023 Olaf Bergmann <bergmann@tzi.org> and others
4  *
5  * SPDX-License-Identifier: BSD-2-Clause
6  *
7  * This file is part of the CoAP library libcoap. Please see
8  * README for terms of use.
9  */
10 
11 /**
12  * @file coap_net.c
13  * @brief CoAP context functions
14  */
15 
16 #include "coap3/coap_internal.h"
17 
18 #include <ctype.h>
19 #include <stdio.h>
20 #ifdef HAVE_LIMITS_H
21 #include <limits.h>
22 #endif
23 #ifdef HAVE_UNISTD_H
24 #include <unistd.h>
25 #else
26 #ifdef HAVE_SYS_UNISTD_H
27 #include <sys/unistd.h>
28 #endif
29 #endif
30 #ifdef HAVE_SYS_TYPES_H
31 #include <sys/types.h>
32 #endif
33 #ifdef HAVE_SYS_SOCKET_H
34 #include <sys/socket.h>
35 #endif
36 #ifdef HAVE_SYS_IOCTL_H
37 #include <sys/ioctl.h>
38 #endif
39 #ifdef HAVE_NETINET_IN_H
40 #include <netinet/in.h>
41 #endif
42 #ifdef HAVE_ARPA_INET_H
43 #include <arpa/inet.h>
44 #endif
45 #ifdef HAVE_NET_IF_H
46 #include <net/if.h>
47 #endif
48 #ifdef COAP_EPOLL_SUPPORT
49 #include <sys/epoll.h>
50 #include <sys/timerfd.h>
51 #endif /* COAP_EPOLL_SUPPORT */
52 #ifdef HAVE_WS2TCPIP_H
53 #include <ws2tcpip.h>
54 #endif
55 
56 #ifdef HAVE_NETDB_H
57 #include <netdb.h>
58 #endif
59 
60 #ifdef WITH_LWIP
61 #include <lwip/pbuf.h>
62 #include <lwip/udp.h>
63 #include <lwip/timeouts.h>
64 #include <lwip/tcpip.h>
65 #endif
66 
67 #ifndef INET6_ADDRSTRLEN
68 #define INET6_ADDRSTRLEN 40
69 #endif
70 
71 #ifndef min
72 #define min(a,b) ((a) < (b) ? (a) : (b))
73 #endif
74 
75 /**
76  * The number of bits for the fractional part of ACK_TIMEOUT and
77  * ACK_RANDOM_FACTOR. Must be less or equal 8.
78  */
79 #define FRAC_BITS 6
80 
81 /**
82  * The maximum number of bits for fixed point integers that are used
83  * for retransmission time calculation. Currently this must be @c 8.
84  */
85 #define MAX_BITS 8
86 
87 #if FRAC_BITS > 8
88 #error FRAC_BITS must be less or equal 8
89 #endif
90 
91 /** creates a Qx.frac from fval in coap_fixed_point_t */
92 #define Q(frac,fval) ((uint16_t)(((1 << (frac)) * fval.integer_part) + \
93                                  ((1 << (frac)) * fval.fractional_part + 500)/1000))
94 
95 /** creates a Qx.FRAC_BITS from session's 'ack_random_factor' */
96 #define ACK_RANDOM_FACTOR                                        \
97   Q(FRAC_BITS, session->ack_random_factor)
98 
99 /** creates a Qx.FRAC_BITS from session's 'ack_timeout' */
100 #define ACK_TIMEOUT Q(FRAC_BITS, session->ack_timeout)
101 
102 #ifndef WITH_LWIP
103 
104 COAP_STATIC_INLINE coap_queue_t *
coap_malloc_node(void)105 coap_malloc_node(void) {
106   return (coap_queue_t *)coap_malloc_type(COAP_NODE, sizeof(coap_queue_t));
107 }
108 
109 COAP_STATIC_INLINE void
coap_free_node(coap_queue_t * node)110 coap_free_node(coap_queue_t *node) {
111   coap_free_type(COAP_NODE, node);
112 }
113 #else /* !WITH_LWIP */
114 
115 #include <lwip/memp.h>
116 
117 COAP_STATIC_INLINE coap_queue_t *
coap_malloc_node()118 coap_malloc_node() {
119   return (coap_queue_t *)memp_malloc(MEMP_COAP_NODE);
120 }
121 
122 COAP_STATIC_INLINE void
coap_free_node(coap_queue_t * node)123 coap_free_node(coap_queue_t *node) {
124   memp_free(MEMP_COAP_NODE, node);
125 }
126 #endif /* WITH_LWIP */
127 
128 unsigned int
coap_adjust_basetime(coap_context_t * ctx,coap_tick_t now)129 coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now) {
130   unsigned int result = 0;
131   coap_tick_diff_t delta = now - ctx->sendqueue_basetime;
132 
133   if (ctx->sendqueue) {
134     /* delta < 0 means that the new time stamp is before the old. */
135     if (delta <= 0) {
136       ctx->sendqueue->t -= delta;
137     } else {
138       /* This case is more complex: The time must be advanced forward,
139        * thus possibly leading to timed out elements at the queue's
140        * start. For every element that has timed out, its relative
141        * time is set to zero and the result counter is increased. */
142 
143       coap_queue_t *q = ctx->sendqueue;
144       coap_tick_t t = 0;
145       while (q && (t + q->t < (coap_tick_t)delta)) {
146         t += q->t;
147         q->t = 0;
148         result++;
149         q = q->next;
150       }
151 
152       /* finally adjust the first element that has not expired */
153       if (q) {
154         q->t = (coap_tick_t)delta - t;
155       }
156     }
157   }
158 
159   /* adjust basetime */
160   ctx->sendqueue_basetime += delta;
161 
162   return result;
163 }
164 
165 int
coap_insert_node(coap_queue_t ** queue,coap_queue_t * node)166 coap_insert_node(coap_queue_t **queue, coap_queue_t *node) {
167   coap_queue_t *p, *q;
168   if (!queue || !node)
169     return 0;
170 
171   /* set queue head if empty */
172   if (!*queue) {
173     *queue = node;
174     return 1;
175   }
176 
177   /* replace queue head if PDU's time is less than head's time */
178   q = *queue;
179   if (node->t < q->t) {
180     node->next = q;
181     *queue = node;
182     q->t -= node->t;                /* make q->t relative to node->t */
183     return 1;
184   }
185 
186   /* search for right place to insert */
187   do {
188     node->t -= q->t;                /* make node-> relative to q->t */
189     p = q;
190     q = q->next;
191   } while (q && q->t <= node->t);
192 
193   /* insert new item */
194   if (q) {
195     q->t -= node->t;                /* make q->t relative to node->t */
196   }
197   node->next = q;
198   p->next = node;
199   return 1;
200 }
201 
202 int
coap_delete_node(coap_queue_t * node)203 coap_delete_node(coap_queue_t *node) {
204   if (!node)
205     return 0;
206 
207   coap_delete_pdu(node->pdu);
208   if (node->session) {
209     /*
210      * Need to remove out of context->sendqueue as added in by coap_wait_ack()
211      */
212     if (node->session->context->sendqueue) {
213       LL_DELETE(node->session->context->sendqueue, node);
214     }
215     coap_session_release(node->session);
216   }
217   coap_free_node(node);
218 
219   return 1;
220 }
221 
222 void
coap_delete_all(coap_queue_t * queue)223 coap_delete_all(coap_queue_t *queue) {
224   if (!queue)
225     return;
226 
227   coap_delete_all(queue->next);
228   coap_delete_node(queue);
229 }
230 
231 coap_queue_t *
coap_new_node(void)232 coap_new_node(void) {
233   coap_queue_t *node;
234   node = coap_malloc_node();
235 
236   if (!node) {
237     coap_log_warn("coap_new_node: malloc failed\n");
238     return NULL;
239   }
240 
241   memset(node, 0, sizeof(*node));
242   return node;
243 }
244 
245 coap_queue_t *
coap_peek_next(coap_context_t * context)246 coap_peek_next(coap_context_t *context) {
247   if (!context || !context->sendqueue)
248     return NULL;
249 
250   return context->sendqueue;
251 }
252 
253 coap_queue_t *
coap_pop_next(coap_context_t * context)254 coap_pop_next(coap_context_t *context) {
255   coap_queue_t *next;
256 
257   if (!context || !context->sendqueue)
258     return NULL;
259 
260   next = context->sendqueue;
261   context->sendqueue = context->sendqueue->next;
262   if (context->sendqueue) {
263     context->sendqueue->t += next->t;
264   }
265   next->next = NULL;
266   return next;
267 }
268 
269 #if COAP_CLIENT_SUPPORT
270 const coap_bin_const_t *
coap_get_session_client_psk_key(const coap_session_t * session)271 coap_get_session_client_psk_key(const coap_session_t *session) {
272 
273   if (session->psk_key) {
274     return session->psk_key;
275   }
276   if (session->cpsk_setup_data.psk_info.key.length)
277     return &session->cpsk_setup_data.psk_info.key;
278 
279   /* Not defined in coap_new_client_session_psk2() */
280   return NULL;
281 }
282 #endif /* COAP_CLIENT_SUPPORT */
283 
284 const coap_bin_const_t *
coap_get_session_client_psk_identity(const coap_session_t * session)285 coap_get_session_client_psk_identity(const coap_session_t *session) {
286 
287   if (session->psk_identity) {
288     return session->psk_identity;
289   }
290   if (session->cpsk_setup_data.psk_info.identity.length)
291     return &session->cpsk_setup_data.psk_info.identity;
292 
293   /* Not defined in coap_new_client_session_psk2() */
294   return NULL;
295 }
296 
297 #if COAP_SERVER_SUPPORT
298 const coap_bin_const_t *
coap_get_session_server_psk_key(const coap_session_t * session)299 coap_get_session_server_psk_key(const coap_session_t *session) {
300 
301   if (session->psk_key)
302     return session->psk_key;
303 
304   if (session->context->spsk_setup_data.psk_info.key.length)
305     return &session->context->spsk_setup_data.psk_info.key;
306 
307   /* Not defined in coap_context_set_psk2() */
308   return NULL;
309 }
310 
311 const coap_bin_const_t *
coap_get_session_server_psk_hint(const coap_session_t * session)312 coap_get_session_server_psk_hint(const coap_session_t *session) {
313 
314   if (session->psk_hint)
315     return session->psk_hint;
316 
317   if (session->context->spsk_setup_data.psk_info.hint.length)
318     return &session->context->spsk_setup_data.psk_info.hint;
319 
320   /* Not defined in coap_context_set_psk2() */
321   return NULL;
322 }
323 
324 int
coap_context_set_psk(coap_context_t * ctx,const char * hint,const uint8_t * key,size_t key_len)325 coap_context_set_psk(coap_context_t *ctx,
326                      const char *hint,
327                      const uint8_t *key,
328                      size_t key_len) {
329   coap_dtls_spsk_t setup_data;
330 
331   memset(&setup_data, 0, sizeof(setup_data));
332   if (hint) {
333     setup_data.psk_info.hint.s = (const uint8_t *)hint;
334     setup_data.psk_info.hint.length = strlen(hint);
335   }
336 
337   if (key && key_len > 0) {
338     setup_data.psk_info.key.s = key;
339     setup_data.psk_info.key.length = key_len;
340   }
341 
342   return coap_context_set_psk2(ctx, &setup_data);
343 }
344 
345 int
coap_context_set_psk2(coap_context_t * ctx,coap_dtls_spsk_t * setup_data)346 coap_context_set_psk2(coap_context_t *ctx, coap_dtls_spsk_t *setup_data) {
347   if (!setup_data)
348     return 0;
349 
350   ctx->spsk_setup_data = *setup_data;
351 
352   if (coap_dtls_is_supported() || coap_tls_is_supported()) {
353     return coap_dtls_context_set_spsk(ctx, setup_data);
354   }
355   return 0;
356 }
357 
358 int
coap_context_set_pki(coap_context_t * ctx,const coap_dtls_pki_t * setup_data)359 coap_context_set_pki(coap_context_t *ctx,
360                      const coap_dtls_pki_t *setup_data) {
361   if (!setup_data)
362     return 0;
363   if (setup_data->version != COAP_DTLS_PKI_SETUP_VERSION) {
364     coap_log_err("coap_context_set_pki: Wrong version of setup_data\n");
365     return 0;
366   }
367   if (coap_dtls_is_supported() || coap_tls_is_supported()) {
368     return coap_dtls_context_set_pki(ctx, setup_data, COAP_DTLS_ROLE_SERVER);
369   }
370   return 0;
371 }
372 #endif /* ! COAP_SERVER_SUPPORT */
373 
374 int
coap_context_set_pki_root_cas(coap_context_t * ctx,const char * ca_file,const char * ca_dir)375 coap_context_set_pki_root_cas(coap_context_t *ctx,
376                               const char *ca_file,
377                               const char *ca_dir) {
378   if (coap_dtls_is_supported() || coap_tls_is_supported()) {
379     return coap_dtls_context_set_pki_root_cas(ctx, ca_file, ca_dir);
380   }
381   return 0;
382 }
383 
384 void
coap_context_set_keepalive(coap_context_t * context,unsigned int seconds)385 coap_context_set_keepalive(coap_context_t *context, unsigned int seconds) {
386   context->ping_timeout = seconds;
387 }
388 
389 void
coap_context_set_max_token_size(coap_context_t * context,size_t max_token_size)390 coap_context_set_max_token_size(coap_context_t *context,
391                                 size_t max_token_size) {
392   assert(max_token_size >= COAP_TOKEN_DEFAULT_MAX &&
393          max_token_size <= COAP_TOKEN_EXT_MAX);
394   context->max_token_size = (uint32_t)max_token_size;
395 }
396 
397 void
coap_context_set_max_idle_sessions(coap_context_t * context,unsigned int max_idle_sessions)398 coap_context_set_max_idle_sessions(coap_context_t *context,
399                                    unsigned int max_idle_sessions) {
400   context->max_idle_sessions = max_idle_sessions;
401 }
402 
403 unsigned int
coap_context_get_max_idle_sessions(const coap_context_t * context)404 coap_context_get_max_idle_sessions(const coap_context_t *context) {
405   return context->max_idle_sessions;
406 }
407 
408 void
coap_context_set_max_handshake_sessions(coap_context_t * context,unsigned int max_handshake_sessions)409 coap_context_set_max_handshake_sessions(coap_context_t *context,
410                                         unsigned int max_handshake_sessions) {
411   context->max_handshake_sessions = max_handshake_sessions;
412 }
413 
414 unsigned int
coap_context_get_max_handshake_sessions(const coap_context_t * context)415 coap_context_get_max_handshake_sessions(const coap_context_t *context) {
416   return context->max_handshake_sessions;
417 }
418 
419 void
coap_context_set_csm_timeout(coap_context_t * context,unsigned int csm_timeout)420 coap_context_set_csm_timeout(coap_context_t *context,
421                              unsigned int csm_timeout) {
422   context->csm_timeout = csm_timeout;
423 }
424 
425 unsigned int
coap_context_get_csm_timeout(const coap_context_t * context)426 coap_context_get_csm_timeout(const coap_context_t *context) {
427   return context->csm_timeout;
428 }
429 
430 void
coap_context_set_csm_max_message_size(coap_context_t * context,uint32_t csm_max_message_size)431 coap_context_set_csm_max_message_size(coap_context_t *context,
432                                       uint32_t csm_max_message_size) {
433   assert(csm_max_message_size >= 64);
434   context->csm_max_message_size = csm_max_message_size;
435 }
436 
437 uint32_t
coap_context_get_csm_max_message_size(const coap_context_t * context)438 coap_context_get_csm_max_message_size(const coap_context_t *context) {
439   return context->csm_max_message_size;
440 }
441 
442 void
coap_context_set_session_timeout(coap_context_t * context,unsigned int session_timeout)443 coap_context_set_session_timeout(coap_context_t *context,
444                                  unsigned int session_timeout) {
445   context->session_timeout = session_timeout;
446 }
447 
448 unsigned int
coap_context_get_session_timeout(const coap_context_t * context)449 coap_context_get_session_timeout(const coap_context_t *context) {
450   return context->session_timeout;
451 }
452 
453 int
coap_context_get_coap_fd(const coap_context_t * context)454 coap_context_get_coap_fd(const coap_context_t *context) {
455 #ifdef COAP_EPOLL_SUPPORT
456   return context->epfd;
457 #else /* ! COAP_EPOLL_SUPPORT */
458   (void)context;
459   return -1;
460 #endif /* ! COAP_EPOLL_SUPPORT */
461 }
462 
463 coap_endpoint_t *
coap_context_get_endpoint(const coap_context_t * context)464 coap_context_get_endpoint(const coap_context_t *context) {
465   if (context != NULL)
466     return context->endpoint;
467   return NULL;
468 }
469 
470 coap_context_t *
coap_new_context(const coap_address_t * listen_addr)471 coap_new_context(const coap_address_t *listen_addr) {
472   coap_context_t *c;
473 
474 #if ! COAP_SERVER_SUPPORT
475   (void)listen_addr;
476 #endif /* COAP_SERVER_SUPPORT */
477 
478   if (!coap_started) {
479     coap_startup();
480     coap_log_warn("coap_startup() should be called before any other "
481                   "coap_*() functions are called\n");
482   }
483 
484   c = coap_malloc_type(COAP_CONTEXT, sizeof(coap_context_t));
485   if (!c) {
486     coap_log_emerg("coap_init: malloc: failed\n");
487     return NULL;
488   }
489   memset(c, 0, sizeof(coap_context_t));
490 
491 #ifdef COAP_EPOLL_SUPPORT
492   c->epfd = epoll_create1(0);
493   if (c->epfd == -1) {
494     coap_log_err("coap_new_context: Unable to epoll_create: %s (%d)\n",
495                  coap_socket_strerror(),
496                  errno);
497     goto onerror;
498   }
499   if (c->epfd != -1) {
500     c->eptimerfd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK);
501     if (c->eptimerfd == -1) {
502       coap_log_err("coap_new_context: Unable to timerfd_create: %s (%d)\n",
503                    coap_socket_strerror(),
504                    errno);
505       goto onerror;
506     } else {
507       int ret;
508       struct epoll_event event;
509 
510       /* Needed if running 32bit as ptr is only 32bit */
511       memset(&event, 0, sizeof(event));
512       event.events = EPOLLIN;
513       /* We special case this event by setting to NULL */
514       event.data.ptr = NULL;
515 
516       ret = epoll_ctl(c->epfd, EPOLL_CTL_ADD, c->eptimerfd, &event);
517       if (ret == -1) {
518         coap_log_err("%s: epoll_ctl ADD failed: %s (%d)\n",
519                      "coap_new_context",
520                      coap_socket_strerror(), errno);
521         goto onerror;
522       }
523     }
524   }
525 #endif /* COAP_EPOLL_SUPPORT */
526 
527   if (coap_dtls_is_supported() || coap_tls_is_supported()) {
528     c->dtls_context = coap_dtls_new_context(c);
529     if (!c->dtls_context) {
530       coap_log_emerg("coap_init: no DTLS context available\n");
531       coap_free_context(c);
532       return NULL;
533     }
534   }
535 
536   /* set default CSM values */
537   c->csm_timeout = 30;
538   c->csm_max_message_size = COAP_DEFAULT_MAX_PDU_RX_SIZE;
539 
540 #if COAP_SERVER_SUPPORT
541   if (listen_addr) {
542     coap_endpoint_t *endpoint = coap_new_endpoint(c, listen_addr, COAP_PROTO_UDP);
543     if (endpoint == NULL) {
544       goto onerror;
545     }
546   }
547 #endif /* COAP_SERVER_SUPPORT */
548 
549   c->max_token_size = COAP_TOKEN_DEFAULT_MAX; /* RFC8974 */
550 
551   return c;
552 
553 #if defined(COAP_EPOLL_SUPPORT) || COAP_SERVER_SUPPORT
554 onerror:
555   coap_free_type(COAP_CONTEXT, c);
556   return NULL;
557 #endif /* COAP_EPOLL_SUPPORT || COAP_SERVER_SUPPORT */
558 }
559 
560 void
coap_set_app_data(coap_context_t * ctx,void * app_data)561 coap_set_app_data(coap_context_t *ctx, void *app_data) {
562   assert(ctx);
563   ctx->app = app_data;
564 }
565 
566 void *
coap_get_app_data(const coap_context_t * ctx)567 coap_get_app_data(const coap_context_t *ctx) {
568   assert(ctx);
569   return ctx->app;
570 }
571 
572 void
coap_free_context(coap_context_t * context)573 coap_free_context(coap_context_t *context) {
574   if (!context)
575     return;
576 
577 #if COAP_SERVER_SUPPORT
578   /* Removing a resource may cause a NON unsolicited observe to be sent */
579   coap_delete_all_resources(context);
580 #endif /* COAP_SERVER_SUPPORT */
581 
582   coap_delete_all(context->sendqueue);
583 
584 #ifdef WITH_LWIP
585   context->sendqueue = NULL;
586   if (context->timer_configured) {
587     LOCK_TCPIP_CORE();
588     sys_untimeout(coap_io_process_timeout, (void *)context);
589     UNLOCK_TCPIP_CORE();
590     context->timer_configured = 0;
591   }
592 #endif /* WITH_LWIP */
593 
594 #if COAP_ASYNC_SUPPORT
595   coap_delete_all_async(context);
596 #endif /* COAP_ASYNC_SUPPORT */
597 
598 #if COAP_OSCORE_SUPPORT
599   coap_delete_all_oscore(context);
600 #endif /* COAP_OSCORE_SUPPORT */
601 
602 #if COAP_SERVER_SUPPORT
603   coap_cache_entry_t *cp, *ctmp;
604 
605   HASH_ITER(hh, context->cache, cp, ctmp) {
606     coap_delete_cache_entry(context, cp);
607   }
608   if (context->cache_ignore_count) {
609     coap_free_type(COAP_STRING, context->cache_ignore_options);
610   }
611 
612   coap_endpoint_t *ep, *tmp;
613 
614   LL_FOREACH_SAFE(context->endpoint, ep, tmp) {
615     coap_free_endpoint(ep);
616   }
617 #endif /* COAP_SERVER_SUPPORT */
618 
619 #if COAP_CLIENT_SUPPORT
620   coap_session_t *sp, *rtmp;
621 
622   SESSIONS_ITER_SAFE(context->sessions, sp, rtmp) {
623     coap_session_release(sp);
624   }
625 #endif /* COAP_CLIENT_SUPPORT */
626 
627   if (context->dtls_context)
628     coap_dtls_free_context(context->dtls_context);
629 #ifdef COAP_EPOLL_SUPPORT
630   if (context->eptimerfd != -1) {
631     int ret;
632     struct epoll_event event;
633 
634     /* Kernels prior to 2.6.9 expect non NULL event parameter */
635     ret = epoll_ctl(context->epfd, EPOLL_CTL_DEL, context->eptimerfd, &event);
636     if (ret == -1) {
637       coap_log_err("%s: epoll_ctl DEL failed: %s (%d)\n",
638                    "coap_free_context",
639                    coap_socket_strerror(), errno);
640     }
641     close(context->eptimerfd);
642     context->eptimerfd = -1;
643   }
644   if (context->epfd != -1) {
645     close(context->epfd);
646     context->epfd = -1;
647   }
648 #endif /* COAP_EPOLL_SUPPORT */
649 #if COAP_SERVER_SUPPORT
650 #if COAP_WITH_OBSERVE_PERSIST
651   coap_persist_cleanup(context);
652 #endif /* COAP_WITH_OBSERVE_PERSIST */
653 #endif /* COAP_SERVER_SUPPORT */
654 
655   coap_free_type(COAP_CONTEXT, context);
656 #ifdef WITH_LWIP
657   coap_lwip_dump_memory_pools(COAP_LOG_DEBUG);
658 #endif /* WITH_LWIP */
659 }
660 
661 int
coap_option_check_critical(coap_session_t * session,coap_pdu_t * pdu,coap_opt_filter_t * unknown)662 coap_option_check_critical(coap_session_t *session,
663                            coap_pdu_t *pdu,
664                            coap_opt_filter_t *unknown) {
665   coap_context_t *ctx = session->context;
666   coap_opt_iterator_t opt_iter;
667   int ok = 1;
668   coap_option_num_t last_number = -1;
669 
670   coap_option_iterator_init(pdu, &opt_iter, COAP_OPT_ALL);
671 
672   while (coap_option_next(&opt_iter)) {
673     if (opt_iter.number & 0x01) {
674       /* first check the known built-in critical options */
675       switch (opt_iter.number) {
676 #if COAP_Q_BLOCK_SUPPORT
677       case COAP_OPTION_Q_BLOCK1:
678       case COAP_OPTION_Q_BLOCK2:
679         if (!(ctx->block_mode & COAP_BLOCK_TRY_Q_BLOCK)) {
680           coap_log_debug("disabled support for critical option %u\n",
681                          opt_iter.number);
682           ok = 0;
683           coap_option_filter_set(unknown, opt_iter.number);
684         }
685         break;
686 #endif /* COAP_Q_BLOCK_SUPPORT */
687       case COAP_OPTION_IF_MATCH:
688       case COAP_OPTION_URI_HOST:
689       case COAP_OPTION_IF_NONE_MATCH:
690       case COAP_OPTION_URI_PORT:
691       case COAP_OPTION_URI_PATH:
692       case COAP_OPTION_URI_QUERY:
693       case COAP_OPTION_ACCEPT:
694       case COAP_OPTION_PROXY_URI:
695       case COAP_OPTION_PROXY_SCHEME:
696       case COAP_OPTION_BLOCK2:
697       case COAP_OPTION_BLOCK1:
698 #ifdef SUPPORT_OPTIC_ONT
699       case COAP_OPTION_ACCESS_TOKEN_ID:
700       case COAP_OPTION_REQ_ID:
701       case COAP_OPTION_DEV_ID:
702       case COAP_OPTION_USER_ID:
703 #endif
704         break;
705       case COAP_OPTION_OSCORE:
706         /* Valid critical if doing OSCORE */
707 #if COAP_OSCORE_SUPPORT
708         if (ctx->p_osc_ctx)
709           break;
710 #endif /* COAP_OSCORE_SUPPORT */
711       /* Fall Through */
712       default:
713         if (coap_option_filter_get(&ctx->known_options, opt_iter.number) <= 0) {
714 #if COAP_SERVER_SUPPORT
715           if ((opt_iter.number & 0x02) == 0) {
716             coap_opt_iterator_t t_iter;
717 
718             /* Safe to forward  - check if proxy pdu */
719             if (session->proxy_session)
720               break;
721             if (COAP_PDU_IS_REQUEST(pdu) && ctx->proxy_uri_resource &&
722                 (coap_check_option(pdu, COAP_OPTION_PROXY_URI, &t_iter) ||
723                  coap_check_option(pdu, COAP_OPTION_PROXY_SCHEME, &t_iter))) {
724               pdu->crit_opt = 1;
725               break;
726             }
727           }
728 #endif /* COAP_SERVER_SUPPORT */
729           coap_log_debug("unknown critical option %d\n", opt_iter.number);
730           ok = 0;
731 
732           /* When opt_iter.number cannot be set in unknown, all of the appropriate
733            * slots have been used up and no more options can be tracked.
734            * Safe to break out of this loop as ok is already set. */
735           if (coap_option_filter_set(unknown, opt_iter.number) == 0) {
736             break;
737           }
738         }
739       }
740     }
741     if (last_number == opt_iter.number) {
742       /* Check for duplicated option RFC 5272 5.4.5 */
743       if (!coap_option_check_repeatable(opt_iter.number)) {
744         ok = 0;
745         if (coap_option_filter_set(unknown, opt_iter.number) == 0) {
746           break;
747         }
748       }
749     } else if (opt_iter.number == COAP_OPTION_BLOCK2 &&
750                COAP_PDU_IS_REQUEST(pdu)) {
751       /* Check the M Bit is not set on a GET request RFC 7959 2.2 */
752       coap_block_b_t block;
753 
754       if (coap_get_block_b(session, pdu, opt_iter.number, &block)) {
755         if (block.m) {
756           size_t used_size = pdu->used_size;
757           unsigned char buf[4];
758 
759           coap_log_debug("Option Block2 has invalid set M bit - cleared\n");
760           block.m = 0;
761           coap_update_option(pdu, opt_iter.number,
762                              coap_encode_var_safe(buf, sizeof(buf),
763                                                   ((block.num << 4) |
764                                                    (block.m << 3) |
765                                                    block.aszx)),
766                              buf);
767           if (used_size != pdu->used_size) {
768             /* Unfortunately need to restart the scan */
769             coap_option_iterator_init(pdu, &opt_iter, COAP_OPT_ALL);
770             last_number = -1;
771             continue;
772           }
773         }
774       }
775     }
776     last_number = opt_iter.number;
777   }
778 
779   return ok;
780 }
781 
782 coap_mid_t
coap_send_ack(coap_session_t * session,const coap_pdu_t * request)783 coap_send_ack(coap_session_t *session, const coap_pdu_t *request) {
784   coap_pdu_t *response;
785   coap_mid_t result = COAP_INVALID_MID;
786 
787   if (request && request->type == COAP_MESSAGE_CON &&
788       COAP_PROTO_NOT_RELIABLE(session->proto)) {
789     response = coap_pdu_init(COAP_MESSAGE_ACK, 0, request->mid, 0);
790     if (response)
791       result = coap_send_internal(session, response);
792   }
793   return result;
794 }
795 
796 ssize_t
coap_session_send_pdu(coap_session_t * session,coap_pdu_t * pdu)797 coap_session_send_pdu(coap_session_t *session, coap_pdu_t *pdu) {
798   ssize_t bytes_written = -1;
799   assert(pdu->hdr_size > 0);
800 
801   /* Caller handles partial writes */
802   bytes_written = session->sock.lfunc[COAP_LAYER_SESSION].l_write(session,
803                   pdu->token - pdu->hdr_size,
804                   pdu->used_size + pdu->hdr_size);
805   coap_show_pdu(COAP_LOG_DEBUG, pdu);
806   return bytes_written;
807 }
808 
809 static ssize_t
coap_send_pdu(coap_session_t * session,coap_pdu_t * pdu,coap_queue_t * node)810 coap_send_pdu(coap_session_t *session, coap_pdu_t *pdu, coap_queue_t *node) {
811   ssize_t bytes_written;
812 
813   if (session->state == COAP_SESSION_STATE_NONE) {
814 #if ! COAP_CLIENT_SUPPORT
815     return -1;
816 #else /* COAP_CLIENT_SUPPORT */
817     if (session->type != COAP_SESSION_TYPE_CLIENT)
818       return -1;
819 #endif /* COAP_CLIENT_SUPPORT */
820   }
821 
822   if (pdu->type == COAP_MESSAGE_CON &&
823       (session->sock.flags & COAP_SOCKET_NOT_EMPTY) &&
824       (session->sock.flags & COAP_SOCKET_MULTICAST)) {
825     /* Violates RFC72522 8.1 */
826     coap_log_err("Multicast requests cannot be Confirmable (RFC7252 8.1)\n");
827     return -1;
828   }
829 
830   if (session->state != COAP_SESSION_STATE_ESTABLISHED ||
831       (pdu->type == COAP_MESSAGE_CON &&
832        session->con_active >= COAP_NSTART(session))) {
833     return coap_session_delay_pdu(session, pdu, node);
834   }
835 
836   if ((session->sock.flags & COAP_SOCKET_NOT_EMPTY) &&
837       (session->sock.flags & COAP_SOCKET_WANT_WRITE))
838     return coap_session_delay_pdu(session, pdu, node);
839 
840   bytes_written = coap_session_send_pdu(session, pdu);
841   if (bytes_written >= 0 && pdu->type == COAP_MESSAGE_CON &&
842       COAP_PROTO_NOT_RELIABLE(session->proto))
843     session->con_active++;
844 
845   return bytes_written;
846 }
847 
848 coap_mid_t
coap_send_error(coap_session_t * session,const coap_pdu_t * request,coap_pdu_code_t code,coap_opt_filter_t * opts)849 coap_send_error(coap_session_t *session,
850                 const coap_pdu_t *request,
851                 coap_pdu_code_t code,
852                 coap_opt_filter_t *opts) {
853   coap_pdu_t *response;
854   coap_mid_t result = COAP_INVALID_MID;
855 
856   assert(request);
857   assert(session);
858 
859   response = coap_new_error_response(request, code, opts);
860   if (response)
861     result = coap_send_internal(session, response);
862 
863   return result;
864 }
865 
866 coap_mid_t
coap_send_message_type(coap_session_t * session,const coap_pdu_t * request,coap_pdu_type_t type)867 coap_send_message_type(coap_session_t *session, const coap_pdu_t *request,
868                        coap_pdu_type_t type) {
869   coap_pdu_t *response;
870   coap_mid_t result = COAP_INVALID_MID;
871 
872   if (request && COAP_PROTO_NOT_RELIABLE(session->proto)) {
873     response = coap_pdu_init(type, 0, request->mid, 0);
874     if (response)
875       result = coap_send_internal(session, response);
876   }
877   return result;
878 }
879 
880 /**
881  * Calculates the initial timeout based on the session CoAP transmission
882  * parameters 'ack_timeout', 'ack_random_factor', and COAP_TICKS_PER_SECOND.
883  * The calculation requires 'ack_timeout' and 'ack_random_factor' to be in
884  * Qx.FRAC_BITS fixed point notation, whereas the passed parameter @p r
885  * is interpreted as the fractional part of a Q0.MAX_BITS random value.
886  *
887  * @param session session timeout is associated with
888  * @param r  random value as fractional part of a Q0.MAX_BITS fixed point
889  *           value
890  * @return   COAP_TICKS_PER_SECOND * 'ack_timeout' *
891  *           (1 + ('ack_random_factor' - 1) * r)
892  */
893 unsigned int
coap_calc_timeout(coap_session_t * session,unsigned char r)894 coap_calc_timeout(coap_session_t *session, unsigned char r) {
895   unsigned int result;
896 
897   /* The integer 1.0 as a Qx.FRAC_BITS */
898 #define FP1 Q(FRAC_BITS, ((coap_fixed_point_t){1,0}))
899 
900   /* rounds val up and right shifts by frac positions */
901 #define SHR_FP(val,frac) (((val) + (1 << ((frac) - 1))) >> (frac))
902 
903   /* Inner term: multiply ACK_RANDOM_FACTOR by Q0.MAX_BITS[r] and
904    * make the result a rounded Qx.FRAC_BITS */
905   result = SHR_FP((ACK_RANDOM_FACTOR - FP1) * r, MAX_BITS);
906 
907   /* Add 1 to the inner term and multiply with ACK_TIMEOUT, then
908    * make the result a rounded Qx.FRAC_BITS */
909   result = SHR_FP(((result + FP1) * ACK_TIMEOUT), FRAC_BITS);
910 
911   /* Multiply with COAP_TICKS_PER_SECOND to yield system ticks
912    * (yields a Qx.FRAC_BITS) and shift to get an integer */
913   return SHR_FP((COAP_TICKS_PER_SECOND * result), FRAC_BITS);
914 
915 #undef FP1
916 #undef SHR_FP
917 }
918 
919 coap_mid_t
coap_wait_ack(coap_context_t * context,coap_session_t * session,coap_queue_t * node)920 coap_wait_ack(coap_context_t *context, coap_session_t *session,
921               coap_queue_t *node) {
922   coap_tick_t now;
923 
924   node->session = coap_session_reference(session);
925 
926   /* Set timer for pdu retransmission. If this is the first element in
927   * the retransmission queue, the base time is set to the current
928   * time and the retransmission time is node->timeout. If there is
929   * already an entry in the sendqueue, we must check if this node is
930   * to be retransmitted earlier. Therefore, node->timeout is first
931   * normalized to the base time and then inserted into the queue with
932   * an adjusted relative time.
933   */
934   coap_ticks(&now);
935   if (context->sendqueue == NULL) {
936     node->t = node->timeout << node->retransmit_cnt;
937     context->sendqueue_basetime = now;
938   } else {
939     /* make node->t relative to context->sendqueue_basetime */
940     node->t = (now - context->sendqueue_basetime) +
941               (node->timeout << node->retransmit_cnt);
942   }
943 
944   coap_insert_node(&context->sendqueue, node);
945 
946   coap_log_debug("** %s: mid=0x%04x: added to retransmit queue (%ums)\n",
947                  coap_session_str(node->session), node->id,
948                  (unsigned)((node->timeout << node->retransmit_cnt) * 1000 /
949                             COAP_TICKS_PER_SECOND));
950 
951 #ifdef COAP_EPOLL_SUPPORT
952   coap_update_epoll_timer(context, node->t);
953 #endif /* COAP_EPOLL_SUPPORT */
954 
955   return node->id;
956 }
957 
958 #if COAP_CLIENT_SUPPORT
959 /*
960  * Sent out a test PDU for Extended Token
961  */
962 static coap_mid_t
coap_send_test_extended_token(coap_session_t * session)963 coap_send_test_extended_token(coap_session_t *session) {
964   coap_pdu_t *pdu;
965   coap_mid_t mid = COAP_INVALID_MID;
966   size_t i;
967   coap_binary_t *token;
968 
969   coap_log_debug("Testing for Extended Token support\n");
970   /* https://rfc-editor.org/rfc/rfc8974#section-2.2.2 */
971   pdu = coap_pdu_init(COAP_MESSAGE_CON, COAP_REQUEST_CODE_GET,
972                       coap_new_message_id(session),
973                       coap_session_max_pdu_size(session));
974   if (!pdu)
975     return COAP_INVALID_MID;
976 
977   token = coap_new_binary(session->max_token_size);
978   if (token == NULL) {
979     coap_delete_pdu(pdu);
980     return COAP_INVALID_MID;
981   }
982   for (i = 0; i < session->max_token_size; i++) {
983     token->s[i] = (uint8_t)(i + 1);
984   }
985   coap_add_token(pdu, session->max_token_size, token->s);
986   coap_delete_binary(token);
987 
988   coap_insert_option(pdu, COAP_OPTION_IF_NONE_MATCH, 0, NULL);
989 
990   session->max_token_checked = COAP_EXT_T_CHECKING; /* Checking out this one */
991   if ((mid = coap_send_internal(session, pdu)) == COAP_INVALID_MID)
992     return COAP_INVALID_MID;
993   session->remote_test_mid = mid;
994   return mid;
995 }
996 #endif /* COAP_CLIENT_SUPPORT */
997 
998 int
coap_client_delay_first(coap_session_t * session)999 coap_client_delay_first(coap_session_t *session) {
1000 #if COAP_CLIENT_SUPPORT
1001   if (session->type == COAP_SESSION_TYPE_CLIENT && session->doing_first) {
1002     int timeout_ms = 5000;
1003 
1004     if (session->delay_recursive) {
1005       assert(0);
1006       return 1;
1007     } else {
1008       session->delay_recursive = 1;
1009     }
1010     /*
1011      * Need to wait for first request to get out and response back before
1012      * continuing.. Response handler has to clear doing_first if not an error.
1013      */
1014     coap_session_reference(session);
1015     while (session->doing_first != 0) {
1016       int result = coap_io_process(session->context, 1000);
1017 
1018       if (result < 0) {
1019         session->doing_first = 0;
1020         session->delay_recursive = 0;
1021         coap_session_release(session);
1022         return 0;
1023       }
1024       if (result <= timeout_ms) {
1025         timeout_ms -= result;
1026       } else {
1027         if (session->doing_first == 1) {
1028           /* Timeout failure of some sort with first request */
1029           coap_log_debug("** %s: timeout waiting for first response\n",
1030                          coap_session_str(session));
1031           session->doing_first = 0;
1032         }
1033       }
1034     }
1035     session->delay_recursive = 0;
1036     coap_session_release(session);
1037   }
1038 #else /* ! COAP_CLIENT_SUPPORT */
1039   (void)session;
1040 #endif /* ! COAP_CLIENT_SUPPORT */
1041   return 1;
1042 }
1043 
1044 coap_mid_t
coap_send(coap_session_t * session,coap_pdu_t * pdu)1045 coap_send(coap_session_t *session, coap_pdu_t *pdu) {
1046   coap_mid_t mid = COAP_INVALID_MID;
1047 #if COAP_CLIENT_SUPPORT
1048   coap_lg_crcv_t *lg_crcv = NULL;
1049   coap_opt_iterator_t opt_iter;
1050   coap_block_b_t block;
1051   int observe_action = -1;
1052   int have_block1 = 0;
1053   coap_opt_t *opt;
1054 #endif /* COAP_CLIENT_SUPPORT */
1055 
1056   assert(pdu);
1057 
1058   pdu->session = session;
1059 #if COAP_CLIENT_SUPPORT
1060   if (session->type == COAP_SESSION_TYPE_CLIENT &&
1061       !coap_netif_available(session)) {
1062     coap_log_debug("coap_send: Socket closed\n");
1063     coap_delete_pdu(pdu);
1064     return COAP_INVALID_MID;
1065   }
1066   /*
1067    * If this is not the first client request and are waiting for a response
1068    * to the first client request, then drop sending out this next request
1069    * until all is properly established.
1070    */
1071   if (!coap_client_delay_first(session)) {
1072     coap_delete_pdu(pdu);
1073     return COAP_INVALID_MID;
1074   }
1075 
1076   /* Indicate support for Extended Tokens if appropriate */
1077   if (session->max_token_checked == COAP_EXT_T_NOT_CHECKED &&
1078       session->max_token_size > COAP_TOKEN_DEFAULT_MAX &&
1079       session->type == COAP_SESSION_TYPE_CLIENT &&
1080       COAP_PDU_IS_REQUEST(pdu)) {
1081     if (COAP_PROTO_NOT_RELIABLE(session->proto)) {
1082       /*
1083        * When the pass / fail response for Extended Token is received, this PDU
1084        * will get transmitted.
1085        */
1086       if (coap_send_test_extended_token(session) == COAP_INVALID_MID) {
1087         coap_delete_pdu(pdu);
1088         return COAP_INVALID_MID;
1089       }
1090     }
1091     /*
1092      * For reliable protocols, this will get cleared after CSM exchanged
1093      * in coap_session_connected()
1094      */
1095     session->doing_first = 1;
1096     if (!coap_client_delay_first(session)) {
1097       coap_delete_pdu(pdu);
1098       return COAP_INVALID_MID;
1099     }
1100   }
1101 
1102   /*
1103    * Check validity of token length
1104    */
1105   if (COAP_PDU_IS_REQUEST(pdu) &&
1106       pdu->actual_token.length > session->max_token_size) {
1107     coap_log_warn("coap_send: PDU dropped as token too long (%zu > %" PRIu32 ")\n",
1108                   pdu->actual_token.length, session->max_token_size);
1109     coap_delete_pdu(pdu);
1110     return COAP_INVALID_MID;
1111   }
1112 
1113   /* A lot of the reliable code assumes type is CON */
1114   if (COAP_PROTO_RELIABLE(session->proto) && pdu->type == COAP_MESSAGE_NON)
1115     pdu->type = COAP_MESSAGE_CON;
1116 
1117 #if COAP_OSCORE_SUPPORT
1118   if (session->oscore_encryption) {
1119     if (session->recipient_ctx->initial_state == 1) {
1120       /*
1121        * Not sure if remote supports OSCORE, or is going to send us a
1122        * "4.01 + ECHO" etc. so need to hold off future coap_send()s until all
1123        * is OK. Continue sending current pdu to test things.
1124        */
1125       session->doing_first = 1;
1126     }
1127     /* Need to convert Proxy-Uri to Proxy-Scheme option if needed */
1128     if (COAP_PDU_IS_REQUEST(pdu) && !coap_rebuild_pdu_for_proxy(pdu)) {
1129       coap_delete_pdu(pdu);
1130       return COAP_INVALID_MID;
1131     }
1132   }
1133 #endif /* COAP_OSCORE_SUPPORT */
1134 
1135   if (!(session->block_mode & COAP_BLOCK_USE_LIBCOAP)) {
1136     return coap_send_internal(session, pdu);
1137   }
1138 
1139   if (COAP_PDU_IS_REQUEST(pdu)) {
1140     uint8_t buf[4];
1141 
1142     opt = coap_check_option(pdu, COAP_OPTION_OBSERVE, &opt_iter);
1143 
1144     if (opt) {
1145       observe_action = coap_decode_var_bytes(coap_opt_value(opt),
1146                                              coap_opt_length(opt));
1147     }
1148 
1149     if (coap_get_block_b(session, pdu, COAP_OPTION_BLOCK1, &block) &&
1150         (block.m == 1 || block.bert == 1)) {
1151       have_block1 = 1;
1152     }
1153 #if COAP_Q_BLOCK_SUPPORT
1154     if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK1, &block) &&
1155         (block.m == 1 || block.bert == 1)) {
1156       if (have_block1) {
1157         coap_log_warn("Block1 and Q-Block1 cannot be in the same request\n");
1158         coap_remove_option(pdu, COAP_OPTION_BLOCK1);
1159       }
1160       have_block1 = 1;
1161     }
1162 #endif /* COAP_Q_BLOCK_SUPPORT */
1163     if (observe_action != COAP_OBSERVE_CANCEL) {
1164       /* Warn about re-use of tokens */
1165       if (session->last_token &&
1166           coap_binary_equal(&pdu->actual_token, session->last_token)) {
1167         coap_log_debug("Token reused - see https://rfc-editor.org/rfc/rfc9175.html#section-4.2\n");
1168       }
1169       coap_delete_bin_const(session->last_token);
1170       session->last_token = coap_new_bin_const(pdu->actual_token.s,
1171                                                pdu->actual_token.length);
1172     }
1173     if (!coap_check_option(pdu, COAP_OPTION_RTAG, &opt_iter) &&
1174         (session->block_mode & COAP_BLOCK_NO_PREEMPTIVE_RTAG) == 0 &&
1175         pdu->code != COAP_REQUEST_CODE_DELETE)
1176       coap_insert_option(pdu,
1177                          COAP_OPTION_RTAG,
1178                          coap_encode_var_safe(buf, sizeof(buf),
1179                                               ++session->tx_rtag),
1180                          buf);
1181   } else {
1182     memset(&block, 0, sizeof(block));
1183   }
1184 
1185 #if COAP_Q_BLOCK_SUPPORT
1186   /* Indicate support for Q-Block if appropriate */
1187   if (session->block_mode & COAP_BLOCK_TRY_Q_BLOCK &&
1188       session->type == COAP_SESSION_TYPE_CLIENT &&
1189       COAP_PDU_IS_REQUEST(pdu)) {
1190     if (coap_block_test_q_block(session, pdu) == COAP_INVALID_MID) {
1191       coap_delete_pdu(pdu);
1192       return COAP_INVALID_MID;
1193     }
1194     session->doing_first = 1;
1195     if (!coap_client_delay_first(session)) {
1196       /* Q-Block test Session has failed for some reason */
1197       set_block_mode_drop_q(session->block_mode);
1198       coap_delete_pdu(pdu);
1199       return COAP_INVALID_MID;
1200     }
1201   }
1202 #endif /* COAP_Q_BLOCK_SUPPORT */
1203 
1204 #if COAP_Q_BLOCK_SUPPORT
1205   if (!(session->block_mode & COAP_BLOCK_HAS_Q_BLOCK))
1206 #endif /* COAP_Q_BLOCK_SUPPORT */
1207   {
1208     /* Need to check if we need to reset Q-Block to Block */
1209     uint8_t buf[4];
1210 
1211     if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK2, &block)) {
1212       coap_remove_option(pdu, COAP_OPTION_Q_BLOCK2);
1213       coap_insert_option(pdu, COAP_OPTION_BLOCK2,
1214                          coap_encode_var_safe(buf, sizeof(buf),
1215                                               (block.num << 4) | (0 << 3) | block.szx),
1216                          buf);
1217       coap_log_debug("Replaced option Q-Block2 with Block2\n");
1218       /* Need to update associated lg_xmit */
1219       coap_lg_xmit_t *lg_xmit;
1220 
1221       LL_FOREACH(session->lg_xmit, lg_xmit) {
1222         if (COAP_PDU_IS_REQUEST(&lg_xmit->pdu) &&
1223             lg_xmit->b.b1.app_token &&
1224             coap_binary_equal(&pdu->actual_token, lg_xmit->b.b1.app_token)) {
1225           /* Update the skeletal PDU with the block1 option */
1226           coap_remove_option(&lg_xmit->pdu, COAP_OPTION_Q_BLOCK2);
1227           coap_update_option(&lg_xmit->pdu, COAP_OPTION_BLOCK2,
1228                              coap_encode_var_safe(buf, sizeof(buf),
1229                                                   (block.num << 4) | (0 << 3) | block.szx),
1230                              buf);
1231           break;
1232         }
1233       }
1234     }
1235     if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK1, &block)) {
1236       coap_remove_option(pdu, COAP_OPTION_Q_BLOCK1);
1237       coap_insert_option(pdu, COAP_OPTION_BLOCK1,
1238                          coap_encode_var_safe(buf, sizeof(buf),
1239                                               (block.num << 4) | (block.m << 3) | block.szx),
1240                          buf);
1241       coap_log_debug("Replaced option Q-Block1 with Block1\n");
1242       /* Need to update associated lg_xmit */
1243       coap_lg_xmit_t *lg_xmit;
1244 
1245       LL_FOREACH(session->lg_xmit, lg_xmit) {
1246         if (COAP_PDU_IS_REQUEST(&lg_xmit->pdu) &&
1247             lg_xmit->b.b1.app_token &&
1248             coap_binary_equal(&pdu->actual_token, lg_xmit->b.b1.app_token)) {
1249           /* Update the skeletal PDU with the block1 option */
1250           coap_remove_option(&lg_xmit->pdu, COAP_OPTION_Q_BLOCK1);
1251           coap_update_option(&lg_xmit->pdu, COAP_OPTION_BLOCK1,
1252                              coap_encode_var_safe(buf, sizeof(buf),
1253                                                   (block.num << 4) |
1254                                                   (block.m << 3) |
1255                                                   block.szx),
1256                              buf);
1257           /* Update as this is a Request */
1258           lg_xmit->option = COAP_OPTION_BLOCK1;
1259           break;
1260         }
1261       }
1262     }
1263   }
1264 
1265 #if COAP_Q_BLOCK_SUPPORT
1266   if (COAP_PDU_IS_REQUEST(pdu) &&
1267       coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK2, &block)) {
1268     if (block.num == 0 && block.m == 0) {
1269       uint8_t buf[4];
1270 
1271       /* M needs to be set as asking for all the blocks */
1272       coap_update_option(pdu, COAP_OPTION_Q_BLOCK2,
1273                          coap_encode_var_safe(buf, sizeof(buf),
1274                                               (0 << 4) | (1 << 3) | block.szx),
1275                          buf);
1276     }
1277   }
1278   if (pdu->type == COAP_MESSAGE_NON && pdu->code == COAP_REQUEST_CODE_FETCH &&
1279       coap_check_option(pdu, COAP_OPTION_OBSERVE, &opt_iter) &&
1280       coap_check_option(pdu, COAP_OPTION_Q_BLOCK1, &opt_iter)) {
1281     /* Issue with Fetch + Observe + Q-Block1 + NON if there are
1282      * retransmits as potential for Token confusion */
1283     pdu->type = COAP_MESSAGE_CON;
1284     /* Need to update associated lg_xmit */
1285     coap_lg_xmit_t *lg_xmit;
1286 
1287     LL_FOREACH(session->lg_xmit, lg_xmit) {
1288       if (lg_xmit->pdu.code == COAP_REQUEST_CODE_FETCH &&
1289           lg_xmit->b.b1.app_token &&
1290           coap_binary_equal(&pdu->actual_token, lg_xmit->b.b1.app_token)) {
1291         /* Update as this is a Request */
1292         lg_xmit->pdu.type = COAP_MESSAGE_CON;
1293         break;
1294       }
1295     }
1296   }
1297 #endif /* COAP_Q_BLOCK_SUPPORT */
1298 
1299   /*
1300    * If type is CON and protocol is not reliable, there is no need to set up
1301    * lg_crcv here as it can be built up based on sent PDU if there is a
1302    * (Q-)Block2 in the response.  However, still need it for Observe, Oscore and
1303    * (Q-)Block1.
1304    */
1305   if (observe_action != -1 || have_block1 ||
1306 #if COAP_OSCORE_SUPPORT
1307       session->oscore_encryption ||
1308 #endif /* COAP_OSCORE_SUPPORT */
1309       ((pdu->type == COAP_MESSAGE_NON || COAP_PROTO_RELIABLE(session->proto)) &&
1310        COAP_PDU_IS_REQUEST(pdu) && pdu->code != COAP_REQUEST_CODE_DELETE)) {
1311     coap_lg_xmit_t *lg_xmit = NULL;
1312 
1313     if (!session->lg_xmit && have_block1) {
1314       coap_log_debug("PDU presented by app\n");
1315       coap_show_pdu(COAP_LOG_DEBUG, pdu);
1316     }
1317     /* See if this token is already in use for large body responses */
1318     LL_FOREACH(session->lg_crcv, lg_crcv) {
1319       if (coap_binary_equal(&pdu->actual_token, lg_crcv->app_token)) {
1320 
1321         if (observe_action == COAP_OBSERVE_CANCEL) {
1322           uint8_t buf[8];
1323           size_t len;
1324 
1325           /* Need to update token to server's version */
1326           len = coap_encode_var_safe8(buf, sizeof(lg_crcv->state_token),
1327                                       lg_crcv->state_token);
1328           if (pdu->code == COAP_REQUEST_CODE_FETCH && lg_crcv->obs_token &&
1329               lg_crcv->obs_token[0]) {
1330             memcpy(buf, lg_crcv->obs_token[0]->s, lg_crcv->obs_token[0]->length);
1331             len = lg_crcv->obs_token[0]->length;
1332           }
1333           coap_update_token(pdu, len, buf);
1334           lg_crcv->initial = 1;
1335           lg_crcv->observe_set = 0;
1336           /* de-reference lg_crcv as potentially linking in later */
1337           LL_DELETE(session->lg_crcv, lg_crcv);
1338           goto send_it;
1339         }
1340 
1341         /* Need to terminate and clean up previous response setup */
1342         LL_DELETE(session->lg_crcv, lg_crcv);
1343         coap_block_delete_lg_crcv(session, lg_crcv);
1344         break;
1345       }
1346     }
1347 
1348     if (have_block1 && session->lg_xmit) {
1349       LL_FOREACH(session->lg_xmit, lg_xmit) {
1350         if (COAP_PDU_IS_REQUEST(&lg_xmit->pdu) &&
1351             lg_xmit->b.b1.app_token &&
1352             coap_binary_equal(&pdu->actual_token, lg_xmit->b.b1.app_token)) {
1353           break;
1354         }
1355       }
1356     }
1357     lg_crcv = coap_block_new_lg_crcv(session, pdu, lg_xmit);
1358     if (lg_crcv == NULL) {
1359       coap_delete_pdu(pdu);
1360       return COAP_INVALID_MID;
1361     }
1362     if (lg_xmit) {
1363       /* Need to update the token as set up in the session->lg_xmit */
1364       lg_xmit->b.b1.state_token = lg_crcv->state_token;
1365     }
1366   }
1367   if (session->sock.flags & COAP_SOCKET_MULTICAST)
1368     coap_address_copy(&session->addr_info.remote, &session->sock.mcast_addr);
1369 
1370 send_it:
1371 #if COAP_Q_BLOCK_SUPPORT
1372   /* See if large xmit using Q-Block1 (but not testing Q-Block1) */
1373   if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK1, &block)) {
1374     mid = coap_send_q_block1(session, block, pdu, COAP_SEND_INC_PDU);
1375   } else
1376 #endif /* COAP_Q_BLOCK_SUPPORT */
1377     mid = coap_send_internal(session, pdu);
1378 #else /* !COAP_CLIENT_SUPPORT */
1379   mid = coap_send_internal(session, pdu);
1380 #endif /* !COAP_CLIENT_SUPPORT */
1381 #if COAP_CLIENT_SUPPORT
1382   if (lg_crcv) {
1383     if (mid != COAP_INVALID_MID) {
1384       LL_PREPEND(session->lg_crcv, lg_crcv);
1385     } else {
1386       coap_block_delete_lg_crcv(session, lg_crcv);
1387     }
1388   }
1389 #endif /* COAP_CLIENT_SUPPORT */
1390   return mid;
1391 }
1392 
1393 coap_mid_t
coap_send_internal(coap_session_t * session,coap_pdu_t * pdu)1394 coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
1395   uint8_t r;
1396   ssize_t bytes_written;
1397   coap_opt_iterator_t opt_iter;
1398 
1399   pdu->session = session;
1400   if (pdu->code == COAP_RESPONSE_CODE(508)) {
1401     /*
1402      * Need to prepend our IP identifier to the data as per
1403      * https://rfc-editor.org/rfc/rfc8768.html#section-4
1404      */
1405     char addr_str[INET6_ADDRSTRLEN + 8 + 1];
1406     coap_opt_t *opt;
1407     size_t hop_limit;
1408 
1409     addr_str[sizeof(addr_str)-1] = '\000';
1410     if (coap_print_addr(&session->addr_info.local, (uint8_t *)addr_str,
1411                         sizeof(addr_str) - 1)) {
1412       char *cp;
1413       size_t len;
1414 
1415       if (addr_str[0] == '[') {
1416         cp = strchr(addr_str, ']');
1417         if (cp)
1418           *cp = '\000';
1419         if (memcmp(&addr_str[1], "::ffff:", 7) == 0) {
1420           /* IPv4 embedded into IPv6 */
1421           cp = &addr_str[8];
1422         } else {
1423           cp = &addr_str[1];
1424         }
1425       } else {
1426         cp = strchr(addr_str, ':');
1427         if (cp)
1428           *cp = '\000';
1429         cp = addr_str;
1430       }
1431       len = strlen(cp);
1432 
1433       /* See if Hop Limit option is being used in return path */
1434       opt = coap_check_option(pdu, COAP_OPTION_HOP_LIMIT, &opt_iter);
1435       if (opt) {
1436         uint8_t buf[4];
1437 
1438         hop_limit =
1439             coap_decode_var_bytes(coap_opt_value(opt), coap_opt_length(opt));
1440         if (hop_limit == 1) {
1441           coap_log_warn("Proxy loop detected '%s'\n",
1442                         (char *)pdu->data);
1443           coap_delete_pdu(pdu);
1444           return (coap_mid_t)COAP_DROPPED_RESPONSE;
1445         } else if (hop_limit < 1 || hop_limit > 255) {
1446           /* Something is bad - need to drop this pdu (TODO or delete option) */
1447           coap_log_warn("Proxy return has bad hop limit count '%zu'\n",
1448                         hop_limit);
1449           coap_delete_pdu(pdu);
1450           return (coap_mid_t)COAP_DROPPED_RESPONSE;
1451         }
1452         hop_limit--;
1453         coap_update_option(pdu, COAP_OPTION_HOP_LIMIT,
1454                            coap_encode_var_safe8(buf, sizeof(buf), hop_limit),
1455                            buf);
1456       }
1457 
1458       /* Need to check that we are not seeing this proxy in the return loop */
1459       if (pdu->data && opt == NULL) {
1460         char *a_match;
1461         size_t data_len;
1462 
1463         if (pdu->used_size + 1 > pdu->max_size) {
1464           /* No space */
1465           return (coap_mid_t)COAP_DROPPED_RESPONSE;
1466         }
1467         if (!coap_pdu_resize(pdu, pdu->used_size + 1)) {
1468           /* Internal error */
1469           return (coap_mid_t)COAP_DROPPED_RESPONSE;
1470         }
1471         data_len = pdu->used_size - (pdu->data - pdu->token);
1472         pdu->data[data_len] = '\000';
1473         a_match = strstr((char *)pdu->data, cp);
1474         if (a_match && (a_match == (char *)pdu->data || a_match[-1] == ' ') &&
1475             ((size_t)(a_match - (char *)pdu->data + len) == data_len ||
1476              a_match[len] == ' ')) {
1477           coap_log_warn("Proxy loop detected '%s'\n",
1478                         (char *)pdu->data);
1479           coap_delete_pdu(pdu);
1480           return (coap_mid_t)COAP_DROPPED_RESPONSE;
1481         }
1482       }
1483       if (pdu->used_size + len + 1 <= pdu->max_size) {
1484         size_t old_size = pdu->used_size;
1485         if (coap_pdu_resize(pdu, pdu->used_size + len + 1)) {
1486           if (pdu->data == NULL) {
1487             /*
1488              * Set Hop Limit to max for return path.  If this libcoap is in
1489              * a proxy loop path, it will always decrement hop limit in code
1490              * above and hence timeout / drop the response as appropriate
1491              */
1492             hop_limit = 255;
1493             coap_insert_option(pdu, COAP_OPTION_HOP_LIMIT, 1,
1494                                (uint8_t *)&hop_limit);
1495             coap_add_data(pdu, len, (uint8_t *)cp);
1496           } else {
1497             /* prepend with space separator, leaving hop limit "as is" */
1498             memmove(pdu->data + len + 1, pdu->data,
1499                     old_size - (pdu->data - pdu->token));
1500             memcpy(pdu->data, cp, len);
1501             pdu->data[len] = ' ';
1502             pdu->used_size += len + 1;
1503           }
1504         }
1505       }
1506     }
1507   }
1508 
1509   if (session->echo) {
1510     if (!coap_insert_option(pdu, COAP_OPTION_ECHO, session->echo->length,
1511                             session->echo->s))
1512       goto error;
1513     coap_delete_bin_const(session->echo);
1514     session->echo = NULL;
1515   }
1516 #if COAP_OSCORE_SUPPORT
1517   if (session->oscore_encryption) {
1518     /* Need to convert Proxy-Uri to Proxy-Scheme option if needed */
1519     if (COAP_PDU_IS_REQUEST(pdu) && !coap_rebuild_pdu_for_proxy(pdu))
1520       goto error;
1521   }
1522 #endif /* COAP_OSCORE_SUPPORT */
1523 
1524   if (!coap_pdu_encode_header(pdu, session->proto)) {
1525     goto error;
1526   }
1527 
1528 #if !COAP_DISABLE_TCP
1529   if (COAP_PROTO_RELIABLE(session->proto) &&
1530       session->state == COAP_SESSION_STATE_ESTABLISHED) {
1531     if (!session->csm_block_supported) {
1532       /*
1533        * Need to check that this instance is not sending any block options as
1534        * the remote end via CSM has not informed us that there is support
1535        * https://rfc-editor.org/rfc/rfc8323#section-5.3.2
1536        * This includes potential BERT blocks.
1537        */
1538       if (coap_check_option(pdu, COAP_OPTION_BLOCK1, &opt_iter) != NULL) {
1539         coap_log_debug("Remote end did not indicate CSM support for Block1 enabled\n");
1540       }
1541       if (coap_check_option(pdu, COAP_OPTION_BLOCK2, &opt_iter) != NULL) {
1542         coap_log_debug("Remote end did not indicate CSM support for Block2 enabled\n");
1543       }
1544     } else if (!session->csm_bert_rem_support) {
1545       coap_opt_t *opt;
1546 
1547       opt = coap_check_option(pdu, COAP_OPTION_BLOCK1, &opt_iter);
1548       if (opt && COAP_OPT_BLOCK_SZX(opt) == 7) {
1549         coap_log_debug("Remote end did not indicate CSM support for BERT Block1\n");
1550       }
1551       opt = coap_check_option(pdu, COAP_OPTION_BLOCK2, &opt_iter);
1552       if (opt && COAP_OPT_BLOCK_SZX(opt) == 7) {
1553         coap_log_debug("Remote end did not indicate CSM support for BERT Block2\n");
1554       }
1555     }
1556   }
1557 #endif /* !COAP_DISABLE_TCP */
1558 
1559 #if COAP_OSCORE_SUPPORT
1560   if (session->oscore_encryption &&
1561       !(pdu->type == COAP_MESSAGE_ACK && pdu->code == COAP_EMPTY_CODE)) {
1562     /* Refactor PDU as appropriate RFC8613 */
1563     coap_pdu_t *osc_pdu = coap_oscore_new_pdu_encrypted(session, pdu, NULL,
1564                                                         0);
1565 
1566     if (osc_pdu == NULL) {
1567       coap_log_warn("OSCORE: PDU could not be encrypted\n");
1568       goto error;
1569     }
1570     bytes_written = coap_send_pdu(session, osc_pdu, NULL);
1571     coap_delete_pdu(pdu);
1572     pdu = osc_pdu;
1573   } else
1574 #endif /* COAP_OSCORE_SUPPORT */
1575     bytes_written = coap_send_pdu(session, pdu, NULL);
1576 
1577   if (bytes_written == COAP_PDU_DELAYED) {
1578     /* do not free pdu as it is stored with session for later use */
1579     return pdu->mid;
1580   }
1581   if (bytes_written < 0) {
1582     goto error;
1583   }
1584 
1585 #if !COAP_DISABLE_TCP
1586   if (COAP_PROTO_RELIABLE(session->proto) &&
1587       (size_t)bytes_written < pdu->used_size + pdu->hdr_size) {
1588     if (coap_session_delay_pdu(session, pdu, NULL) == COAP_PDU_DELAYED) {
1589       session->partial_write = (size_t)bytes_written;
1590       /* do not free pdu as it is stored with session for later use */
1591       return pdu->mid;
1592     } else {
1593       goto error;
1594     }
1595   }
1596 #endif /* !COAP_DISABLE_TCP */
1597 
1598   if (pdu->type != COAP_MESSAGE_CON
1599       || COAP_PROTO_RELIABLE(session->proto)) {
1600     coap_mid_t id = pdu->mid;
1601     coap_delete_pdu(pdu);
1602     return id;
1603   }
1604 
1605   coap_queue_t *node = coap_new_node();
1606   if (!node) {
1607     coap_log_debug("coap_wait_ack: insufficient memory\n");
1608     goto error;
1609   }
1610 
1611   node->id = pdu->mid;
1612   node->pdu = pdu;
1613   coap_prng(&r, sizeof(r));
1614   /* add timeout in range [ACK_TIMEOUT...ACK_TIMEOUT * ACK_RANDOM_FACTOR] */
1615   node->timeout = coap_calc_timeout(session, r);
1616   return coap_wait_ack(session->context, session, node);
1617 error:
1618   coap_delete_pdu(pdu);
1619   return COAP_INVALID_MID;
1620 }
1621 
1622 coap_mid_t
coap_retransmit(coap_context_t * context,coap_queue_t * node)1623 coap_retransmit(coap_context_t *context, coap_queue_t *node) {
1624   if (!context || !node)
1625     return COAP_INVALID_MID;
1626 
1627   /* re-initialize timeout when maximum number of retransmissions are not reached yet */
1628   if (node->retransmit_cnt < node->session->max_retransmit) {
1629     ssize_t bytes_written;
1630     coap_tick_t now;
1631     coap_tick_t next_delay;
1632 
1633     node->retransmit_cnt++;
1634     coap_handle_event(context, COAP_EVENT_MSG_RETRANSMITTED, node->session);
1635 
1636     next_delay = (coap_tick_t)node->timeout << node->retransmit_cnt;
1637     if (context->ping_timeout &&
1638         context->ping_timeout * COAP_TICKS_PER_SECOND < next_delay) {
1639       uint8_t byte;
1640 
1641       coap_prng(&byte, sizeof(byte));
1642       /* Don't exceed the ping timeout value */
1643       next_delay = context->ping_timeout * COAP_TICKS_PER_SECOND - 255 + byte;
1644     }
1645 
1646     coap_ticks(&now);
1647     if (context->sendqueue == NULL) {
1648       node->t = next_delay;
1649       context->sendqueue_basetime = now;
1650     } else {
1651       /* make node->t relative to context->sendqueue_basetime */
1652       node->t = (now - context->sendqueue_basetime) + next_delay;
1653     }
1654     coap_insert_node(&context->sendqueue, node);
1655 
1656     if (node->is_mcast) {
1657       coap_log_debug("** %s: mid=0x%04x: mcast delayed transmission\n",
1658                      coap_session_str(node->session), node->id);
1659     } else {
1660       coap_log_debug("** %s: mid=0x%04x: retransmission #%d (next %ums)\n",
1661                      coap_session_str(node->session), node->id,
1662                      node->retransmit_cnt,
1663                      (unsigned)(next_delay * 1000 / COAP_TICKS_PER_SECOND));
1664     }
1665 
1666     if (node->session->con_active)
1667       node->session->con_active--;
1668     bytes_written = coap_send_pdu(node->session, node->pdu, node);
1669 
1670     if (node->is_mcast) {
1671       coap_session_connected(node->session);
1672       coap_delete_node(node);
1673       return COAP_INVALID_MID;
1674     }
1675     if (bytes_written == COAP_PDU_DELAYED) {
1676       /* PDU was not retransmitted immediately because a new handshake is
1677          in progress. node was moved to the send queue of the session. */
1678       return node->id;
1679     }
1680 
1681     if (bytes_written < 0)
1682       return (int)bytes_written;
1683 
1684     return node->id;
1685   }
1686 
1687   /* no more retransmissions, remove node from system */
1688   coap_log_warn("** %s: mid=0x%04x: give up after %d attempts\n",
1689                 coap_session_str(node->session), node->id, node->retransmit_cnt);
1690 
1691 #if COAP_SERVER_SUPPORT
1692   /* Check if subscriptions exist that should be canceled after
1693      COAP_OBS_MAX_FAIL */
1694   if (COAP_RESPONSE_CLASS(node->pdu->code) >= 2) {
1695     coap_handle_failed_notify(context, node->session, &node->pdu->actual_token);
1696   }
1697 #endif /* COAP_SERVER_SUPPORT */
1698   if (node->session->con_active) {
1699     node->session->con_active--;
1700     if (node->session->state == COAP_SESSION_STATE_ESTABLISHED) {
1701       /*
1702        * As there may be another CON in a different queue entry on the same
1703        * session that needs to be immediately released,
1704        * coap_session_connected() is called.
1705        * However, there is the possibility coap_wait_ack() may be called for
1706        * this node (queue) and re-added to context->sendqueue.
1707        * coap_delete_node(node) called shortly will handle this and remove it.
1708        */
1709       coap_session_connected(node->session);
1710     }
1711   }
1712 
1713   /* And finally delete the node */
1714   if (node->pdu->type == COAP_MESSAGE_CON && context->nack_handler) {
1715     coap_check_update_token(node->session, node->pdu);
1716     context->nack_handler(node->session, node->pdu, COAP_NACK_TOO_MANY_RETRIES, node->id);
1717   }
1718   coap_delete_node(node);
1719   return COAP_INVALID_MID;
1720 }
1721 
1722 static int
coap_handle_dgram_for_proto(coap_context_t * ctx,coap_session_t * session,coap_packet_t * packet)1723 coap_handle_dgram_for_proto(coap_context_t *ctx, coap_session_t *session, coap_packet_t *packet) {
1724   uint8_t *data;
1725   size_t data_len;
1726   int result = -1;
1727 
1728   coap_packet_get_memmapped(packet, &data, &data_len);
1729   if (session->proto == COAP_PROTO_DTLS) {
1730 #if COAP_SERVER_SUPPORT
1731     if (session->type == COAP_SESSION_TYPE_HELLO)
1732       result = coap_dtls_hello(session, data, data_len);
1733     else
1734 #endif /* COAP_SERVER_SUPPORT */
1735       if (session->tls)
1736         result = coap_dtls_receive(session, data, data_len);
1737   } else if (session->proto == COAP_PROTO_UDP) {
1738     result = coap_handle_dgram(ctx, session, data, data_len);
1739   }
1740   return result;
1741 }
1742 
1743 #if COAP_CLIENT_SUPPORT
1744 static void
coap_connect_session(coap_session_t * session,coap_tick_t now)1745 coap_connect_session(coap_session_t *session, coap_tick_t now) {
1746 #if COAP_DISABLE_TCP
1747   (void)now;
1748 
1749   session->sock.flags &= ~(COAP_SOCKET_WANT_CONNECT | COAP_SOCKET_CAN_CONNECT);
1750 #else /* !COAP_DISABLE_TCP */
1751   if (coap_netif_strm_connect2(session)) {
1752     session->last_rx_tx = now;
1753     coap_handle_event(session->context, COAP_EVENT_TCP_CONNECTED, session);
1754     session->sock.lfunc[COAP_LAYER_SESSION].l_establish(session);
1755   } else {
1756     coap_handle_event(session->context, COAP_EVENT_TCP_FAILED, session);
1757     coap_session_disconnected(session, COAP_NACK_NOT_DELIVERABLE);
1758   }
1759 #endif /* !COAP_DISABLE_TCP */
1760 }
1761 #endif /* COAP_CLIENT_SUPPORT */
1762 
1763 static void
coap_write_session(coap_context_t * ctx,coap_session_t * session,coap_tick_t now)1764 coap_write_session(coap_context_t *ctx, coap_session_t *session, coap_tick_t now) {
1765   (void)ctx;
1766   assert(session->sock.flags & COAP_SOCKET_CONNECTED);
1767 
1768   while (session->delayqueue) {
1769     ssize_t bytes_written;
1770     coap_queue_t *q = session->delayqueue;
1771     coap_log_debug("** %s: mid=0x%04x: transmitted after delay\n",
1772                    coap_session_str(session), (int)q->pdu->mid);
1773     assert(session->partial_write < q->pdu->used_size + q->pdu->hdr_size);
1774     bytes_written = session->sock.lfunc[COAP_LAYER_SESSION].l_write(session,
1775                     q->pdu->token - q->pdu->hdr_size + session->partial_write,
1776                     q->pdu->used_size + q->pdu->hdr_size - session->partial_write);
1777     if (bytes_written > 0)
1778       session->last_rx_tx = now;
1779     if (bytes_written <= 0 ||
1780         (size_t)bytes_written < q->pdu->used_size + q->pdu->hdr_size - session->partial_write) {
1781       if (bytes_written > 0)
1782         session->partial_write += (size_t)bytes_written;
1783       break;
1784     }
1785     session->delayqueue = q->next;
1786     session->partial_write = 0;
1787     coap_delete_node(q);
1788   }
1789 }
1790 
1791 static void
coap_read_session(coap_context_t * ctx,coap_session_t * session,coap_tick_t now)1792 coap_read_session(coap_context_t *ctx, coap_session_t *session, coap_tick_t now) {
1793 #if COAP_CONSTRAINED_STACK
1794   /* payload and packet protected by mutex m_read_session */
1795   static unsigned char payload[COAP_RXBUFFER_SIZE];
1796   static coap_packet_t s_packet;
1797 #else /* ! COAP_CONSTRAINED_STACK */
1798   unsigned char payload[COAP_RXBUFFER_SIZE];
1799   coap_packet_t s_packet;
1800 #endif /* ! COAP_CONSTRAINED_STACK */
1801   coap_packet_t *packet = &s_packet;
1802 
1803 #if COAP_CONSTRAINED_STACK
1804   coap_mutex_lock(&m_read_session);
1805 #endif /* COAP_CONSTRAINED_STACK */
1806 
1807 #ifdef COAP_SUPPORT_SOCKET_BROADCAST
1808   assert(session->sock.flags & (COAP_SOCKET_CONNECTED | COAP_SOCKET_MULTICAST | COAP_SOCKET_BROADCAST));
1809 #else
1810   assert(session->sock.flags & (COAP_SOCKET_CONNECTED | COAP_SOCKET_MULTICAST));
1811 #endif
1812 
1813   packet->length = sizeof(payload);
1814   packet->payload = payload;
1815 
1816   if (COAP_PROTO_NOT_RELIABLE(session->proto)) {
1817     ssize_t bytes_read;
1818     memcpy(&packet->addr_info, &session->addr_info, sizeof(packet->addr_info));
1819     bytes_read = coap_netif_dgrm_read(session, packet);
1820 
1821     if (bytes_read < 0) {
1822       if (bytes_read == -2)
1823         /* Reset the session back to startup defaults */
1824         coap_session_disconnected(session, COAP_NACK_ICMP_ISSUE);
1825     } else if (bytes_read > 0) {
1826       session->last_rx_tx = now;
1827       memcpy(&session->addr_info, &packet->addr_info,
1828              sizeof(session->addr_info));
1829       coap_handle_dgram_for_proto(ctx, session, packet);
1830     }
1831 #if !COAP_DISABLE_TCP
1832   } else if (session->proto == COAP_PROTO_WS ||
1833              session->proto == COAP_PROTO_WSS) {
1834     ssize_t bytes_read = 0;
1835 
1836     /* WebSocket layer passes us the whole packet */
1837     bytes_read = session->sock.lfunc[COAP_LAYER_SESSION].l_read(session,
1838                                                                 packet->payload,
1839                                                                 packet->length);
1840     if (bytes_read < 0) {
1841       coap_session_disconnected(session, COAP_NACK_NOT_DELIVERABLE);
1842     } else if (bytes_read > 2) {
1843       coap_pdu_t *pdu;
1844 
1845       session->last_rx_tx = now;
1846       /* Need max space incase PDU is updated with updated token etc. */
1847       pdu = coap_pdu_init(0, 0, 0, coap_session_max_pdu_rcv_size(session));
1848       if (!pdu) {
1849 #if COAP_CONSTRAINED_STACK
1850         coap_mutex_unlock(&m_read_session);
1851 #endif /* COAP_CONSTRAINED_STACK */
1852         return;
1853       }
1854 
1855       if (!coap_pdu_parse(session->proto, packet->payload, bytes_read, pdu)) {
1856         coap_handle_event(session->context, COAP_EVENT_BAD_PACKET, session);
1857         coap_log_warn("discard malformed PDU\n");
1858         coap_delete_pdu(pdu);
1859 #if COAP_CONSTRAINED_STACK
1860         coap_mutex_unlock(&m_read_session);
1861 #endif /* COAP_CONSTRAINED_STACK */
1862         return;
1863       }
1864 
1865 #if COAP_CONSTRAINED_STACK
1866       coap_mutex_unlock(&m_read_session);
1867 #endif /* COAP_CONSTRAINED_STACK */
1868       coap_dispatch(ctx, session, pdu);
1869       coap_delete_pdu(pdu);
1870       return;
1871     }
1872   } else {
1873     ssize_t bytes_read = 0;
1874     const uint8_t *p;
1875     int retry;
1876 
1877     do {
1878       bytes_read = session->sock.lfunc[COAP_LAYER_SESSION].l_read(session,
1879                                                                   packet->payload,
1880                                                                   packet->length);
1881       if (bytes_read > 0) {
1882         session->last_rx_tx = now;
1883       }
1884       p = packet->payload;
1885       retry = bytes_read == (ssize_t)packet->length;
1886       while (bytes_read > 0) {
1887         if (session->partial_pdu) {
1888           size_t len = session->partial_pdu->used_size
1889                        + session->partial_pdu->hdr_size
1890                        - session->partial_read;
1891           size_t n = min(len, (size_t)bytes_read);
1892           memcpy(session->partial_pdu->token - session->partial_pdu->hdr_size
1893                  + session->partial_read, p, n);
1894           p += n;
1895           bytes_read -= n;
1896           if (n == len) {
1897             if (coap_pdu_parse_header(session->partial_pdu, session->proto)
1898                 && coap_pdu_parse_opt(session->partial_pdu)) {
1899 #if COAP_CONSTRAINED_STACK
1900               coap_mutex_unlock(&m_read_session);
1901 #endif /* COAP_CONSTRAINED_STACK */
1902               coap_dispatch(ctx, session, session->partial_pdu);
1903 #if COAP_CONSTRAINED_STACK
1904               coap_mutex_lock(&m_read_session);
1905 #endif /* COAP_CONSTRAINED_STACK */
1906             }
1907             coap_delete_pdu(session->partial_pdu);
1908             session->partial_pdu = NULL;
1909             session->partial_read = 0;
1910           } else {
1911             session->partial_read += n;
1912           }
1913         } else if (session->partial_read > 0) {
1914 #ifdef SUPPORT_OPTIC_ONT
1915           size_t hdr_size = coap_pdu_get_fix_header_size();
1916 #else
1917           size_t hdr_size = coap_pdu_parse_header_size(session->proto,
1918             session->read_header);
1919 #endif
1920           size_t tkl = session->read_header[0] & 0x0f;
1921           size_t tok_ext_bytes = tkl == COAP_TOKEN_EXT_1B_TKL ? 1 :
1922                                  tkl == COAP_TOKEN_EXT_2B_TKL ? 2 : 0;
1923           size_t len = hdr_size + tok_ext_bytes - session->partial_read;
1924           size_t n = min(len, (size_t)bytes_read);
1925           memcpy(session->read_header + session->partial_read, p, n);
1926           p += n;
1927           bytes_read -= n;
1928           if (n == len) {
1929 #ifdef SUPPORT_OPTIC_ONT
1930             size_t size = coap_pdu_parse_fix_header_size(session->proto, session->read_header,
1931               hdr_size + tok_ext_bytes);
1932 #else
1933             size_t size = coap_pdu_parse_size(session->proto, session->read_header,
1934               hdr_size + tok_ext_bytes);
1935 #endif
1936             if (size > COAP_DEFAULT_MAX_PDU_RX_SIZE) {
1937               coap_log_warn("** %s: incoming PDU length too large (%zu > %lu)\n",
1938                             coap_session_str(session),
1939                             size, COAP_DEFAULT_MAX_PDU_RX_SIZE);
1940               bytes_read = -1;
1941               break;
1942             }
1943             /* Need max space incase PDU is updated with updated token etc. */
1944             session->partial_pdu = coap_pdu_init(0, 0, 0,
1945                                                  coap_session_max_pdu_rcv_size(session));
1946             if (session->partial_pdu == NULL) {
1947               bytes_read = -1;
1948               break;
1949             }
1950             if (session->partial_pdu->alloc_size < size && !coap_pdu_resize(session->partial_pdu, size)) {
1951               bytes_read = -1;
1952               break;
1953             }
1954             session->partial_pdu->hdr_size = (uint8_t)hdr_size;
1955 #ifdef SUPPORT_OPTIC_ONT
1956             session->partial_pdu->used_size = size - 2;
1957 #else
1958             session->partial_pdu->used_size = size;
1959 #endif /* !SUPPORT_OPTIC_ONT */
1960             memcpy(session->partial_pdu->token - hdr_size, session->read_header, hdr_size + tok_ext_bytes);
1961             session->partial_read = hdr_size + tok_ext_bytes;
1962             if (size == 0) {
1963               if (coap_pdu_parse_header(session->partial_pdu, session->proto)) {
1964 #if COAP_CONSTRAINED_STACK
1965                 coap_mutex_unlock(&m_read_session);
1966 #endif /* COAP_CONSTRAINED_STACK */
1967                 coap_dispatch(ctx, session, session->partial_pdu);
1968 #if COAP_CONSTRAINED_STACK
1969                 coap_mutex_lock(&m_read_session);
1970 #endif /* COAP_CONSTRAINED_STACK */
1971               }
1972               coap_delete_pdu(session->partial_pdu);
1973               session->partial_pdu = NULL;
1974               session->partial_read = 0;
1975             }
1976           } else {
1977             session->partial_read += bytes_read;
1978           }
1979         } else {
1980           session->read_header[0] = *p++;
1981           bytes_read -= 1;
1982 #ifdef SUPPORT_OPTIC_ONT
1983           if (!coap_pdu_get_fix_header_size()) {
1984 #else
1985           if (!coap_pdu_parse_header_size(session->proto,
1986                                           session->read_header)) {
1987 #endif
1988             bytes_read = -1;
1989             break;
1990           }
1991           session->partial_read = 1;
1992         }
1993       }
1994     } while (bytes_read == 0 && retry);
1995     if (bytes_read < 0)
1996       coap_session_disconnected(session, COAP_NACK_NOT_DELIVERABLE);
1997 #endif /* !COAP_DISABLE_TCP */
1998   }
1999 #if COAP_CONSTRAINED_STACK
2000   coap_mutex_unlock(&m_read_session);
2001 #endif /* COAP_CONSTRAINED_STACK */
2002 }
2003 
2004 #if COAP_SERVER_SUPPORT
2005 static int
2006 coap_read_endpoint(coap_context_t *ctx, coap_endpoint_t *endpoint, coap_tick_t now) {
2007   ssize_t bytes_read = -1;
2008   int result = -1;                /* the value to be returned */
2009 #if COAP_CONSTRAINED_STACK
2010   /* payload and e_packet protected by mutex m_read_endpoint */
2011   static unsigned char payload[COAP_RXBUFFER_SIZE];
2012   static coap_packet_t e_packet;
2013 #else /* ! COAP_CONSTRAINED_STACK */
2014   unsigned char payload[COAP_RXBUFFER_SIZE];
2015   coap_packet_t e_packet;
2016 #endif /* ! COAP_CONSTRAINED_STACK */
2017   coap_packet_t *packet = &e_packet;
2018 
2019   assert(COAP_PROTO_NOT_RELIABLE(endpoint->proto));
2020   assert(endpoint->sock.flags & COAP_SOCKET_BOUND);
2021 
2022 #if COAP_CONSTRAINED_STACK
2023   coap_mutex_lock(&m_read_endpoint);
2024 #endif /* COAP_CONSTRAINED_STACK */
2025 
2026   /* Need to do this as there may be holes in addr_info */
2027   memset(&packet->addr_info, 0, sizeof(packet->addr_info));
2028   packet->length = sizeof(payload);
2029   packet->payload = payload;
2030   coap_address_init(&packet->addr_info.remote);
2031   coap_address_copy(&packet->addr_info.local, &endpoint->bind_addr);
2032 
2033   bytes_read = coap_netif_dgrm_read_ep(endpoint, packet);
2034   if (bytes_read < 0) {
2035     coap_log_warn("*  %s: read failed\n", coap_endpoint_str(endpoint));
2036   } else if (bytes_read > 0) {
2037     coap_session_t *session = coap_endpoint_get_session(endpoint, packet, now);
2038     if (session) {
2039       coap_log_debug("*  %s: netif: recv %4zd bytes\n",
2040                      coap_session_str(session), bytes_read);
2041       result = coap_handle_dgram_for_proto(ctx, session, packet);
2042       if (endpoint->proto == COAP_PROTO_DTLS && session->type == COAP_SESSION_TYPE_HELLO && result == 1)
2043         coap_session_new_dtls_session(session, now);
2044     }
2045   }
2046 #if COAP_CONSTRAINED_STACK
2047   coap_mutex_unlock(&m_read_endpoint);
2048 #endif /* COAP_CONSTRAINED_STACK */
2049   return result;
2050 }
2051 
2052 static int
2053 coap_write_endpoint(coap_context_t *ctx, coap_endpoint_t *endpoint, coap_tick_t now) {
2054   (void)ctx;
2055   (void)endpoint;
2056   (void)now;
2057   return 0;
2058 }
2059 
2060 #if !COAP_DISABLE_TCP
2061 static int
2062 coap_accept_endpoint(coap_context_t *ctx, coap_endpoint_t *endpoint,
2063                      coap_tick_t now) {
2064   coap_session_t *session = coap_new_server_session(ctx, endpoint);
2065   if (session)
2066     session->last_rx_tx = now;
2067   return session != NULL;
2068 }
2069 #endif /* !COAP_DISABLE_TCP */
2070 #endif /* COAP_SERVER_SUPPORT */
2071 
2072 void
2073 coap_io_do_io(coap_context_t *ctx, coap_tick_t now) {
2074 #ifdef COAP_EPOLL_SUPPORT
2075   (void)ctx;
2076   (void)now;
2077   coap_log_emerg("coap_io_do_io() requires libcoap not compiled for using epoll\n");
2078 #else /* ! COAP_EPOLL_SUPPORT */
2079   coap_session_t *s, *rtmp;
2080 
2081 #if COAP_SERVER_SUPPORT
2082   coap_endpoint_t *ep, *tmp;
2083   LL_FOREACH_SAFE(ctx->endpoint, ep, tmp) {
2084     if ((ep->sock.flags & COAP_SOCKET_CAN_READ) != 0)
2085       coap_read_endpoint(ctx, ep, now);
2086     if ((ep->sock.flags & COAP_SOCKET_CAN_WRITE) != 0)
2087       coap_write_endpoint(ctx, ep, now);
2088 #if !COAP_DISABLE_TCP
2089     if ((ep->sock.flags & COAP_SOCKET_CAN_ACCEPT) != 0)
2090       coap_accept_endpoint(ctx, ep, now);
2091 #endif /* !COAP_DISABLE_TCP */
2092     SESSIONS_ITER_SAFE(ep->sessions, s, rtmp) {
2093       /* Make sure the session object is not deleted in one of the callbacks  */
2094       coap_session_reference(s);
2095       if ((s->sock.flags & COAP_SOCKET_CAN_READ) != 0) {
2096         coap_read_session(ctx, s, now);
2097       }
2098       if ((s->sock.flags & COAP_SOCKET_CAN_WRITE) != 0) {
2099         coap_write_session(ctx, s, now);
2100       }
2101       coap_session_release(s);
2102     }
2103   }
2104 #endif /* COAP_SERVER_SUPPORT */
2105 
2106 #if COAP_CLIENT_SUPPORT
2107   SESSIONS_ITER_SAFE(ctx->sessions, s, rtmp) {
2108     /* Make sure the session object is not deleted in one of the callbacks  */
2109     coap_session_reference(s);
2110     if ((s->sock.flags & COAP_SOCKET_CAN_CONNECT) != 0) {
2111       coap_connect_session(s, now);
2112     }
2113     if ((s->sock.flags & COAP_SOCKET_CAN_READ) != 0 && s->ref > 1) {
2114       coap_read_session(ctx, s, now);
2115     }
2116     if ((s->sock.flags & COAP_SOCKET_CAN_WRITE) != 0 && s->ref > 1) {
2117       coap_write_session(ctx, s, now);
2118     }
2119     coap_session_release(s);
2120   }
2121 #endif /* COAP_CLIENT_SUPPORT */
2122 #endif /* ! COAP_EPOLL_SUPPORT */
2123 }
2124 
2125 /*
2126  * While this code in part replicates coap_io_do_io(), doing the functions
2127  * directly saves having to iterate through the endpoints / sessions.
2128  */
2129 void
2130 coap_io_do_epoll(coap_context_t *ctx, struct epoll_event *events, size_t nevents) {
2131 #ifndef COAP_EPOLL_SUPPORT
2132   (void)ctx;
2133   (void)events;
2134   (void)nevents;
2135   coap_log_emerg("coap_io_do_epoll() requires libcoap compiled for using epoll\n");
2136 #else /* COAP_EPOLL_SUPPORT */
2137   coap_tick_t now;
2138   size_t j;
2139 
2140   coap_ticks(&now);
2141   for (j = 0; j < nevents; j++) {
2142     coap_socket_t *sock = (coap_socket_t *)events[j].data.ptr;
2143 
2144     /* Ignore 'timer trigger' ptr  which is NULL */
2145     if (sock) {
2146 #if COAP_SERVER_SUPPORT
2147       if (sock->endpoint) {
2148         coap_endpoint_t *endpoint = sock->endpoint;
2149         if ((sock->flags & COAP_SOCKET_WANT_READ) &&
2150             (events[j].events & EPOLLIN)) {
2151           sock->flags |= COAP_SOCKET_CAN_READ;
2152           coap_read_endpoint(endpoint->context, endpoint, now);
2153         }
2154 
2155         if ((sock->flags & COAP_SOCKET_WANT_WRITE) &&
2156             (events[j].events & EPOLLOUT)) {
2157           /*
2158            * Need to update this to EPOLLIN as EPOLLOUT will normally always
2159            * be true causing epoll_wait to return early
2160            */
2161           coap_epoll_ctl_mod(sock, EPOLLIN, __func__);
2162           sock->flags |= COAP_SOCKET_CAN_WRITE;
2163           coap_write_endpoint(endpoint->context, endpoint, now);
2164         }
2165 
2166 #if !COAP_DISABLE_TCP
2167         if ((sock->flags & COAP_SOCKET_WANT_ACCEPT) &&
2168             (events[j].events & EPOLLIN)) {
2169           sock->flags |= COAP_SOCKET_CAN_ACCEPT;
2170           coap_accept_endpoint(endpoint->context, endpoint, now);
2171         }
2172 #endif /* !COAP_DISABLE_TCP */
2173 
2174       } else
2175 #endif /* COAP_SERVER_SUPPORT */
2176         if (sock->session) {
2177           coap_session_t *session = sock->session;
2178 
2179           /* Make sure the session object is not deleted
2180              in one of the callbacks  */
2181           coap_session_reference(session);
2182 #if COAP_CLIENT_SUPPORT
2183           if ((sock->flags & COAP_SOCKET_WANT_CONNECT) &&
2184               (events[j].events & (EPOLLOUT|EPOLLERR|EPOLLHUP|EPOLLRDHUP))) {
2185             sock->flags |= COAP_SOCKET_CAN_CONNECT;
2186             coap_connect_session(session, now);
2187             if (coap_netif_available(session) &&
2188                 !(sock->flags & COAP_SOCKET_WANT_WRITE)) {
2189               coap_epoll_ctl_mod(sock, EPOLLIN, __func__);
2190             }
2191           }
2192 #endif /* COAP_CLIENT_SUPPORT */
2193 
2194           if ((sock->flags & COAP_SOCKET_WANT_READ) &&
2195               (events[j].events & (EPOLLIN|EPOLLERR|EPOLLHUP|EPOLLRDHUP))) {
2196             sock->flags |= COAP_SOCKET_CAN_READ;
2197             coap_read_session(session->context, session, now);
2198           }
2199 
2200           if ((sock->flags & COAP_SOCKET_WANT_WRITE) &&
2201               (events[j].events & (EPOLLOUT|EPOLLERR|EPOLLHUP|EPOLLRDHUP))) {
2202             /*
2203              * Need to update this to EPOLLIN as EPOLLOUT will normally always
2204              * be true causing epoll_wait to return early
2205              */
2206             coap_epoll_ctl_mod(sock, EPOLLIN, __func__);
2207             sock->flags |= COAP_SOCKET_CAN_WRITE;
2208             coap_write_session(session->context, session, now);
2209           }
2210           /* Now dereference session so it can go away if needed */
2211           coap_session_release(session);
2212         }
2213     } else if (ctx->eptimerfd != -1) {
2214       /*
2215        * 'timer trigger' must have fired. eptimerfd needs to be read to clear
2216        *  it so that it does not set EPOLLIN in the next epoll_wait().
2217        */
2218       uint64_t count;
2219 
2220       /* Check the result from read() to suppress the warning on
2221        * systems that declare read() with warn_unused_result. */
2222       if (read(ctx->eptimerfd, &count, sizeof(count)) == -1) {
2223         /* do nothing */;
2224       }
2225     }
2226   }
2227   /* And update eptimerfd as to when to next trigger */
2228   coap_ticks(&now);
2229   coap_io_prepare_epoll(ctx, now);
2230 #endif /* COAP_EPOLL_SUPPORT */
2231 }
2232 
2233 int
2234 coap_handle_dgram(coap_context_t *ctx, coap_session_t *session,
2235                   uint8_t *msg, size_t msg_len) {
2236 
2237   coap_pdu_t *pdu = NULL;
2238 
2239   assert(COAP_PROTO_NOT_RELIABLE(session->proto));
2240   if (msg_len < 4) {
2241     /* Minimum size of CoAP header - ignore runt */
2242     return -1;
2243   }
2244 
2245   /* Need max space incase PDU is updated with updated token etc. */
2246   pdu = coap_pdu_init(0, 0, 0, coap_session_max_pdu_rcv_size(session));
2247   if (!pdu)
2248     goto error;
2249 
2250   if (!coap_pdu_parse(session->proto, msg, msg_len, pdu)) {
2251     coap_handle_event(session->context, COAP_EVENT_BAD_PACKET, session);
2252     coap_log_warn("discard malformed PDU\n");
2253     goto error;
2254   }
2255 
2256   coap_dispatch(ctx, session, pdu);
2257   coap_delete_pdu(pdu);
2258   return 0;
2259 
2260 error:
2261   /*
2262    * https://rfc-editor.org/rfc/rfc7252#section-4.2 MUST send RST
2263    * https://rfc-editor.org/rfc/rfc7252#section-4.3 MAY send RST
2264    */
2265   coap_send_rst(session, pdu);
2266   coap_delete_pdu(pdu);
2267   return -1;
2268 }
2269 
2270 int
2271 coap_remove_from_queue(coap_queue_t **queue, coap_session_t *session, coap_mid_t id,
2272                        coap_queue_t **node) {
2273   coap_queue_t *p, *q;
2274 
2275   if (!queue || !*queue)
2276     return 0;
2277 
2278   /* replace queue head if PDU's time is less than head's time */
2279 
2280   if (session == (*queue)->session && id == (*queue)->id) { /* found message id */
2281     *node = *queue;
2282     *queue = (*queue)->next;
2283     if (*queue) {          /* adjust relative time of new queue head */
2284       (*queue)->t += (*node)->t;
2285     }
2286     (*node)->next = NULL;
2287     coap_log_debug("** %s: mid=0x%04x: removed (1)\n",
2288                    coap_session_str(session), id);
2289     return 1;
2290   }
2291 
2292   /* search message id queue to remove (only first occurence will be removed) */
2293   q = *queue;
2294   do {
2295     p = q;
2296     q = q->next;
2297   } while (q && (session != q->session || id != q->id));
2298 
2299   if (q) {                        /* found message id */
2300     p->next = q->next;
2301     if (p->next) {                /* must update relative time of p->next */
2302       p->next->t += q->t;
2303     }
2304     q->next = NULL;
2305     *node = q;
2306     coap_log_debug("** %s: mid=0x%04x: removed (2)\n",
2307                    coap_session_str(session), id);
2308     return 1;
2309   }
2310 
2311   return 0;
2312 
2313 }
2314 
2315 void
2316 coap_cancel_session_messages(coap_context_t *context, coap_session_t *session,
2317                              coap_nack_reason_t reason) {
2318   coap_queue_t *p, *q;
2319 
2320   while (context->sendqueue && context->sendqueue->session == session) {
2321     q = context->sendqueue;
2322     context->sendqueue = q->next;
2323     coap_log_debug("** %s: mid=0x%04x: removed (3)\n",
2324                    coap_session_str(session), q->id);
2325     if (q->pdu->type == COAP_MESSAGE_CON && context->nack_handler) {
2326       coap_check_update_token(session, q->pdu);
2327       context->nack_handler(session, q->pdu, reason, q->id);
2328     }
2329     coap_delete_node(q);
2330   }
2331 
2332   if (!context->sendqueue)
2333     return;
2334 
2335   p = context->sendqueue;
2336   q = p->next;
2337 
2338   while (q) {
2339     if (q->session == session) {
2340       p->next = q->next;
2341       coap_log_debug("** %s: mid=0x%04x: removed (4)\n",
2342                      coap_session_str(session), q->id);
2343       if (q->pdu->type == COAP_MESSAGE_CON && context->nack_handler) {
2344         coap_check_update_token(session, q->pdu);
2345         context->nack_handler(session, q->pdu, reason, q->id);
2346       }
2347       coap_delete_node(q);
2348       q = p->next;
2349     } else {
2350       p = q;
2351       q = q->next;
2352     }
2353   }
2354 }
2355 
2356 void
2357 coap_cancel_all_messages(coap_context_t *context, coap_session_t *session,
2358                          coap_bin_const_t *token) {
2359   /* cancel all messages in sendqueue that belong to session
2360    * and use the specified token */
2361   coap_queue_t **p, *q;
2362 
2363   if (!context->sendqueue)
2364     return;
2365 
2366   p = &context->sendqueue;
2367   q = *p;
2368 
2369   while (q) {
2370     if (q->session == session &&
2371         coap_binary_equal(&q->pdu->actual_token, token)) {
2372       *p = q->next;
2373       coap_log_debug("** %s: mid=0x%04x: removed (6)\n",
2374                      coap_session_str(session), q->id);
2375       if (q->pdu->type == COAP_MESSAGE_CON && session->con_active) {
2376         session->con_active--;
2377         if (session->state == COAP_SESSION_STATE_ESTABLISHED)
2378           /* Flush out any entries on session->delayqueue */
2379           coap_session_connected(session);
2380       }
2381       coap_delete_node(q);
2382     } else {
2383       p = &(q->next);
2384     }
2385     q = *p;
2386   }
2387 }
2388 
2389 coap_pdu_t *
2390 coap_new_error_response(const coap_pdu_t *request, coap_pdu_code_t code,
2391                         coap_opt_filter_t *opts) {
2392   coap_opt_iterator_t opt_iter;
2393   coap_pdu_t *response;
2394   size_t size = request->e_token_length;
2395   unsigned char type;
2396   coap_opt_t *option;
2397   coap_option_num_t opt_num = 0;        /* used for calculating delta-storage */
2398 
2399 #if COAP_ERROR_PHRASE_LENGTH > 0
2400   const char *phrase;
2401   if (code != COAP_RESPONSE_CODE(508)) {
2402     phrase = coap_response_phrase(code);
2403 
2404     /* Need some more space for the error phrase and payload start marker */
2405     if (phrase)
2406       size += strlen(phrase) + 1;
2407   } else {
2408     /*
2409      * Need space for IP for 5.08 response which is filled in in
2410      * coap_send_internal()
2411      * https://rfc-editor.org/rfc/rfc8768.html#section-4
2412      */
2413     phrase = NULL;
2414     size += INET6_ADDRSTRLEN;
2415   }
2416 #endif
2417 
2418   assert(request);
2419 
2420   /* cannot send ACK if original request was not confirmable */
2421   type = request->type == COAP_MESSAGE_CON ?
2422          COAP_MESSAGE_ACK : COAP_MESSAGE_NON;
2423 
2424   /* Estimate how much space we need for options to copy from
2425    * request. We always need the Token, for 4.02 the unknown critical
2426    * options must be included as well. */
2427 
2428   /* we do not want these */
2429   coap_option_filter_unset(opts, COAP_OPTION_CONTENT_FORMAT);
2430   coap_option_filter_unset(opts, COAP_OPTION_HOP_LIMIT);
2431   /* Unsafe to send this back */
2432   coap_option_filter_unset(opts, COAP_OPTION_OSCORE);
2433 
2434   coap_option_iterator_init(request, &opt_iter, opts);
2435 
2436   /* Add size of each unknown critical option. As known critical
2437      options as well as elective options are not copied, the delta
2438      value might grow.
2439    */
2440   while ((option = coap_option_next(&opt_iter))) {
2441     uint16_t delta = opt_iter.number - opt_num;
2442     /* calculate space required to encode (opt_iter.number - opt_num) */
2443     if (delta < 13) {
2444       size++;
2445     } else if (delta < 269) {
2446       size += 2;
2447     } else {
2448       size += 3;
2449     }
2450 
2451     /* add coap_opt_length(option) and the number of additional bytes
2452      * required to encode the option length */
2453 
2454     size += coap_opt_length(option);
2455     switch (*option & 0x0f) {
2456     case 0x0e:
2457       size++;
2458     /* fall through */
2459     case 0x0d:
2460       size++;
2461       break;
2462     default:
2463       ;
2464     }
2465 
2466     opt_num = opt_iter.number;
2467   }
2468 
2469   /* Now create the response and fill with options and payload data. */
2470   response = coap_pdu_init(type, code, request->mid, size);
2471   if (response) {
2472     /* copy token */
2473     if (!coap_add_token(response, request->actual_token.length,
2474                         request->actual_token.s)) {
2475       coap_log_debug("cannot add token to error response\n");
2476       coap_delete_pdu(response);
2477       return NULL;
2478     }
2479 
2480     /* copy all options */
2481     coap_option_iterator_init(request, &opt_iter, opts);
2482     while ((option = coap_option_next(&opt_iter))) {
2483       coap_add_option_internal(response, opt_iter.number,
2484                                coap_opt_length(option),
2485                                coap_opt_value(option));
2486     }
2487 
2488 #if COAP_ERROR_PHRASE_LENGTH > 0
2489     /* note that diagnostic messages do not need a Content-Format option. */
2490     if (phrase)
2491       coap_add_data(response, (size_t)strlen(phrase), (const uint8_t *)phrase);
2492 #endif
2493   }
2494 
2495   return response;
2496 }
2497 
2498 #if COAP_SERVER_SUPPORT
2499 /**
2500  * Quick hack to determine the size of the resource description for
2501  * .well-known/core.
2502  */
2503 COAP_STATIC_INLINE ssize_t
2504 get_wkc_len(coap_context_t *context, const coap_string_t *query_filter) {
2505   unsigned char buf[1];
2506   size_t len = 0;
2507 
2508   if (coap_print_wellknown(context, buf, &len, UINT_MAX, query_filter) &
2509       COAP_PRINT_STATUS_ERROR) {
2510     coap_log_warn("cannot determine length of /.well-known/core\n");
2511     return -1L;
2512   }
2513 
2514   return len;
2515 }
2516 
2517 #define SZX_TO_BYTES(SZX) ((size_t)(1 << ((SZX) + 4)))
2518 
2519 static void
2520 free_wellknown_response(coap_session_t *session COAP_UNUSED, void *app_ptr) {
2521   coap_delete_string(app_ptr);
2522 }
2523 
2524 static void
2525 hnd_get_wellknown(coap_resource_t *resource,
2526                   coap_session_t *session,
2527                   const coap_pdu_t *request,
2528                   const coap_string_t *query,
2529                   coap_pdu_t *response) {
2530   size_t len = 0;
2531   coap_string_t *data_string = NULL;
2532   int result = 0;
2533   ssize_t wkc_len = get_wkc_len(session->context, query);
2534 
2535   if (wkc_len) {
2536     if (wkc_len < 0)
2537       goto error;
2538     data_string = coap_new_string(wkc_len);
2539     if (!data_string)
2540       goto error;
2541 
2542     len = wkc_len;
2543     result = coap_print_wellknown(session->context, data_string->s, &len, 0,
2544                                   query);
2545     if ((result & COAP_PRINT_STATUS_ERROR) != 0) {
2546       coap_log_debug("coap_print_wellknown failed\n");
2547       goto error;
2548     }
2549     assert(len <= (size_t)wkc_len);
2550     data_string->length = len;
2551 
2552     if (!(session->block_mode & COAP_BLOCK_USE_LIBCOAP)) {
2553       uint8_t buf[4];
2554 
2555       if (!coap_insert_option(response, COAP_OPTION_CONTENT_FORMAT,
2556                               coap_encode_var_safe(buf, sizeof(buf),
2557                                                    COAP_MEDIATYPE_APPLICATION_LINK_FORMAT), buf)) {
2558         goto error;
2559       }
2560       if (response->used_size + len + 1 > response->max_size) {
2561         /*
2562          * Data does not fit into a packet and no libcoap block support
2563          * +1 for end of options marker
2564          */
2565         coap_log_debug(".well-known/core: truncating data length to %zu from %zu\n",
2566                        len, response->max_size  - response->used_size - 1);
2567         len = response->max_size - response->used_size - 1;
2568       }
2569       if (!coap_add_data(response, len, data_string->s)) {
2570         goto error;
2571       }
2572       free_wellknown_response(session, data_string);
2573     } else if (!coap_add_data_large_response(resource, session, request,
2574                                              response, query,
2575                                              COAP_MEDIATYPE_APPLICATION_LINK_FORMAT,
2576                                              -1, 0, data_string->length,
2577                                              data_string->s,
2578                                              free_wellknown_response,
2579                                              data_string)) {
2580       goto error_released;
2581     }
2582   }
2583   response->code = COAP_RESPONSE_CODE(205);
2584   return;
2585 
2586 error:
2587   free_wellknown_response(session, data_string);
2588 error_released:
2589   if (response->code == 0) {
2590     /* set error code 5.03 and remove all options and data from response */
2591     response->code = COAP_RESPONSE_CODE(503);
2592     response->used_size = response->e_token_length;
2593     response->data = NULL;
2594   }
2595 }
2596 #endif /* COAP_SERVER_SUPPORT */
2597 
2598 /**
2599  * This function cancels outstanding messages for the session and
2600  * token specified in @p sent. Any observation relationship for
2601  * sent->session and the token are removed. Calling this function is
2602  * required when receiving an RST message (usually in response to a
2603  * notification) or a GET request with the Observe option set to 1.
2604  *
2605  * This function returns @c 0 when the token is unknown with this
2606  * peer, or a value greater than zero otherwise.
2607  */
2608 static int
2609 coap_cancel(coap_context_t *context, const coap_queue_t *sent) {
2610   int num_cancelled = 0;    /* the number of observers cancelled */
2611 
2612 #ifndef COAP_SERVER_SUPPORT
2613   (void)sent;
2614 #endif /* ! COAP_SERVER_SUPPORT */
2615   (void)context;
2616 
2617 #if COAP_SERVER_SUPPORT
2618   /* remove observer for this resource, if any
2619    * Use token from sent and try to find a matching resource. Uh!
2620    */
2621   RESOURCES_ITER(context->resources, r) {
2622     coap_cancel_all_messages(context, sent->session, &sent->pdu->actual_token);
2623     num_cancelled += coap_delete_observer(r, sent->session, &sent->pdu->actual_token);
2624   }
2625 #endif /* COAP_SERVER_SUPPORT */
2626 
2627   return num_cancelled;
2628 }
2629 
2630 #if COAP_SERVER_SUPPORT
2631 /**
2632  * Internal flags to control the treatment of responses (specifically
2633  * in presence of the No-Response option).
2634  */
2635 enum respond_t { RESPONSE_DEFAULT, RESPONSE_DROP, RESPONSE_SEND };
2636 
2637 /*
2638  * Checks for No-Response option in given @p request and
2639  * returns @c RESPONSE_DROP if @p response should be suppressed
2640  * according to RFC 7967.
2641  *
2642  * If the response is a confirmable piggybacked response and RESPONSE_DROP,
2643  * change it to an empty ACK and @c RESPONSE_SEND so the client does not keep
2644  * on retrying.
2645  *
2646  * Checks if the response code is 0.00 and if either the session is reliable or
2647  * non-confirmable, @c RESPONSE_DROP is also returned.
2648  *
2649  * Multicast response checking is also carried out.
2650  *
2651  * NOTE: It is the responsibility of the application to determine whether
2652  * a delayed separate response should be sent as the original requesting packet
2653  * containing the No-Response option has long since gone.
2654  *
2655  * The value of the No-Response option is encoded as
2656  * follows:
2657  *
2658  * @verbatim
2659  *  +-------+-----------------------+-----------------------------------+
2660  *  | Value | Binary Representation |          Description              |
2661  *  +-------+-----------------------+-----------------------------------+
2662  *  |   0   |      <empty>          | Interested in all responses.      |
2663  *  +-------+-----------------------+-----------------------------------+
2664  *  |   2   |      00000010         | Not interested in 2.xx responses. |
2665  *  +-------+-----------------------+-----------------------------------+
2666  *  |   8   |      00001000         | Not interested in 4.xx responses. |
2667  *  +-------+-----------------------+-----------------------------------+
2668  *  |  16   |      00010000         | Not interested in 5.xx responses. |
2669  *  +-------+-----------------------+-----------------------------------+
2670  * @endverbatim
2671  *
2672  * @param request  The CoAP request to check for the No-Response option.
2673  *                 This parameter must not be NULL.
2674  * @param response The response that is potentially suppressed.
2675  *                 This parameter must not be NULL.
2676  * @param session  The session this request/response are associated with.
2677  *                 This parameter must not be NULL.
2678  * @return RESPONSE_DEFAULT when no special treatment is requested,
2679  *         RESPONSE_DROP    when the response must be discarded, or
2680  *         RESPONSE_SEND    when the response must be sent.
2681  */
2682 static enum respond_t
2683 no_response(coap_pdu_t *request, coap_pdu_t *response,
2684             coap_session_t *session, coap_resource_t *resource) {
2685   coap_opt_t *nores;
2686   coap_opt_iterator_t opt_iter;
2687   unsigned int val = 0;
2688 
2689   assert(request);
2690   assert(response);
2691 
2692   if (COAP_RESPONSE_CLASS(response->code) > 0) {
2693     nores = coap_check_option(request, COAP_OPTION_NORESPONSE, &opt_iter);
2694 
2695     if (nores) {
2696       val = coap_decode_var_bytes(coap_opt_value(nores), coap_opt_length(nores));
2697 
2698       /* The response should be dropped when the bit corresponding to
2699        * the response class is set (cf. table in function
2700        * documentation). When a No-Response option is present and the
2701        * bit is not set, the sender explicitly indicates interest in
2702        * this response. */
2703       if (((1 << (COAP_RESPONSE_CLASS(response->code) - 1)) & val) > 0) {
2704         /* Should be dropping the response */
2705         if (response->type == COAP_MESSAGE_ACK &&
2706             COAP_PROTO_NOT_RELIABLE(session->proto)) {
2707           /* Still need to ACK the request */
2708           response->code = 0;
2709           /* Remove token/data from piggybacked acknowledgment PDU */
2710           response->actual_token.length = 0;
2711           response->e_token_length = 0;
2712           response->used_size = 0;
2713           response->data = NULL;
2714           return RESPONSE_SEND;
2715         } else {
2716           return RESPONSE_DROP;
2717         }
2718       } else {
2719         /* True for mcast as well RFC7967 2.1 */
2720         return RESPONSE_SEND;
2721       }
2722     } else if (resource && session->context->mcast_per_resource &&
2723                coap_is_mcast(&session->addr_info.local)) {
2724       /* Handle any mcast suppression specifics if no NoResponse option */
2725       if ((resource->flags &
2726            COAP_RESOURCE_FLAGS_LIB_ENA_MCAST_SUPPRESS_2_XX) &&
2727           COAP_RESPONSE_CLASS(response->code) == 2) {
2728         return RESPONSE_DROP;
2729       } else if ((resource->flags &
2730                   COAP_RESOURCE_FLAGS_LIB_ENA_MCAST_SUPPRESS_2_05) &&
2731                  response->code == COAP_RESPONSE_CODE(205)) {
2732         if (response->data == NULL)
2733           return RESPONSE_DROP;
2734       } else if ((resource->flags &
2735                   COAP_RESOURCE_FLAGS_LIB_DIS_MCAST_SUPPRESS_4_XX) == 0 &&
2736                  COAP_RESPONSE_CLASS(response->code) == 4) {
2737         return RESPONSE_DROP;
2738       } else if ((resource->flags &
2739                   COAP_RESOURCE_FLAGS_LIB_DIS_MCAST_SUPPRESS_5_XX) == 0 &&
2740                  COAP_RESPONSE_CLASS(response->code) == 5) {
2741         return RESPONSE_DROP;
2742       }
2743     }
2744   } else if (COAP_PDU_IS_EMPTY(response) &&
2745              (response->type == COAP_MESSAGE_NON ||
2746               COAP_PROTO_RELIABLE(session->proto))) {
2747     /* response is 0.00, and this is reliable or non-confirmable */
2748     return RESPONSE_DROP;
2749   }
2750 
2751   /*
2752    * Do not send error responses for requests that were received via
2753    * IP multicast.  RFC7252 8.1
2754    */
2755 
2756   if (coap_is_mcast(&session->addr_info.local)) {
2757     if (request->type == COAP_MESSAGE_NON &&
2758         response->type == COAP_MESSAGE_RST)
2759       return RESPONSE_DROP;
2760 
2761     if ((!resource || session->context->mcast_per_resource == 0) &&
2762         COAP_RESPONSE_CLASS(response->code) > 2)
2763       return RESPONSE_DROP;
2764   }
2765 
2766   /* Default behavior applies when we are not dealing with a response
2767    * (class == 0) or the request did not contain a No-Response option.
2768    */
2769   return RESPONSE_DEFAULT;
2770 }
2771 
2772 static coap_str_const_t coap_default_uri_wellknown = {
2773   sizeof(COAP_DEFAULT_URI_WELLKNOWN)-1,
2774   (const uint8_t *)COAP_DEFAULT_URI_WELLKNOWN
2775 };
2776 
2777 /* Initialized in coap_startup() */
2778 static coap_resource_t resource_uri_wellknown;
2779 
2780 static void
2781 handle_request(coap_context_t *context, coap_session_t *session, coap_pdu_t *pdu) {
2782   coap_method_handler_t h = NULL;
2783   coap_pdu_t *response = NULL;
2784   coap_opt_filter_t opt_filter;
2785   coap_resource_t *resource = NULL;
2786   /* The respond field indicates whether a response must be treated
2787    * specially due to a No-Response option that declares disinterest
2788    * or interest in a specific response class. DEFAULT indicates that
2789    * No-Response has not been specified. */
2790   enum respond_t respond = RESPONSE_DEFAULT;
2791   coap_opt_iterator_t opt_iter;
2792   coap_opt_t *opt;
2793   int is_proxy_uri = 0;
2794   int is_proxy_scheme = 0;
2795   int skip_hop_limit_check = 0;
2796   int resp = 0;
2797   int send_early_empty_ack = 0;
2798   coap_string_t *query = NULL;
2799   coap_opt_t *observe = NULL;
2800   coap_string_t *uri_path = NULL;
2801   int observe_action = COAP_OBSERVE_CANCEL;
2802   coap_block_b_t block;
2803   int added_block = 0;
2804   coap_lg_srcv_t *free_lg_srcv = NULL;
2805 #if COAP_Q_BLOCK_SUPPORT
2806   int lg_xmit_ctrl = 0;
2807 #endif /* COAP_Q_BLOCK_SUPPORT */
2808 #if COAP_ASYNC_SUPPORT
2809   coap_async_t *async;
2810 #endif /* COAP_ASYNC_SUPPORT */
2811 
2812   if (coap_is_mcast(&session->addr_info.local)) {
2813     if (COAP_PROTO_RELIABLE(session->proto) || pdu->type != COAP_MESSAGE_NON) {
2814       coap_log_info("Invalid multicast packet received RFC7252 8.1\n");
2815       return;
2816     }
2817   }
2818 #if COAP_ASYNC_SUPPORT
2819   async = coap_find_async(session, pdu->actual_token);
2820   if (async) {
2821     coap_tick_t now;
2822 
2823     coap_ticks(&now);
2824     if (async->delay == 0 || async->delay > now) {
2825       /* re-transmit missing ACK (only if CON) */
2826       coap_log_info("Retransmit async response\n");
2827       coap_send_ack(session, pdu);
2828       /* and do not pass on to the upper layers */
2829       return;
2830     }
2831   }
2832 #endif /* COAP_ASYNC_SUPPORT */
2833 
2834   coap_option_filter_clear(&opt_filter);
2835   opt = coap_check_option(pdu, COAP_OPTION_PROXY_SCHEME, &opt_iter);
2836   if (opt) {
2837     opt = coap_check_option(pdu, COAP_OPTION_URI_HOST, &opt_iter);
2838     if (!opt) {
2839       coap_log_debug("Proxy-Scheme requires Uri-Host\n");
2840       resp = 402;
2841       goto fail_response;
2842     }
2843     is_proxy_scheme = 1;
2844   }
2845 
2846   opt = coap_check_option(pdu, COAP_OPTION_PROXY_URI, &opt_iter);
2847   if (opt)
2848     is_proxy_uri = 1;
2849 
2850   if (is_proxy_scheme || is_proxy_uri) {
2851     coap_uri_t uri;
2852 
2853     if (!context->proxy_uri_resource) {
2854       /* Need to return a 5.05 RFC7252 Section 5.7.2 */
2855       coap_log_debug("Proxy-%s support not configured\n",
2856                      is_proxy_scheme ? "Scheme" : "Uri");
2857       resp = 505;
2858       goto fail_response;
2859     }
2860     if (((size_t)pdu->code - 1 <
2861          (sizeof(resource->handler) / sizeof(resource->handler[0]))) &&
2862         !(context->proxy_uri_resource->handler[pdu->code - 1])) {
2863       /* Need to return a 5.05 RFC7252 Section 5.7.2 */
2864       coap_log_debug("Proxy-%s code %d.%02d handler not supported\n",
2865                      is_proxy_scheme ? "Scheme" : "Uri",
2866                      pdu->code/100,  pdu->code%100);
2867       resp = 505;
2868       goto fail_response;
2869     }
2870 
2871     /* Need to check if authority is the proxy endpoint RFC7252 Section 5.7.2 */
2872     if (is_proxy_uri) {
2873       if (coap_split_proxy_uri(coap_opt_value(opt),
2874                                coap_opt_length(opt), &uri) < 0) {
2875         /* Need to return a 5.05 RFC7252 Section 5.7.2 */
2876         coap_log_debug("Proxy-URI not decodable\n");
2877         resp = 505;
2878         goto fail_response;
2879       }
2880     } else {
2881       memset(&uri, 0, sizeof(uri));
2882       opt = coap_check_option(pdu, COAP_OPTION_URI_HOST, &opt_iter);
2883       if (opt) {
2884         uri.host.length = coap_opt_length(opt);
2885         uri.host.s = coap_opt_value(opt);
2886       } else
2887         uri.host.length = 0;
2888     }
2889 
2890     resource = context->proxy_uri_resource;
2891     if (uri.host.length && resource->proxy_name_count &&
2892         resource->proxy_name_list) {
2893       size_t i;
2894 
2895       if (resource->proxy_name_count == 1 &&
2896           resource->proxy_name_list[0]->length == 0) {
2897         /* If proxy_name_list[0] is zero length, then this is the endpoint */
2898         i = 0;
2899       } else {
2900         for (i = 0; i < resource->proxy_name_count; i++) {
2901           if (coap_string_equal(&uri.host, resource->proxy_name_list[i])) {
2902             break;
2903           }
2904         }
2905       }
2906       if (i != resource->proxy_name_count) {
2907         /* This server is hosting the proxy connection endpoint */
2908         if (pdu->crit_opt) {
2909           /* Cannot handle critical option */
2910           pdu->crit_opt = 0;
2911           resp = 402;
2912           goto fail_response;
2913         }
2914         is_proxy_uri = 0;
2915         is_proxy_scheme = 0;
2916         skip_hop_limit_check = 1;
2917       }
2918     }
2919     resource = NULL;
2920   }
2921 
2922   if (!skip_hop_limit_check) {
2923     opt = coap_check_option(pdu, COAP_OPTION_HOP_LIMIT, &opt_iter);
2924     if (opt) {
2925       size_t hop_limit;
2926       uint8_t buf[4];
2927 
2928       hop_limit =
2929           coap_decode_var_bytes(coap_opt_value(opt), coap_opt_length(opt));
2930       if (hop_limit == 1) {
2931         /* coap_send_internal() will fill in the IP address for us */
2932         resp = 508;
2933         goto fail_response;
2934       } else if (hop_limit < 1 || hop_limit > 255) {
2935         /* Need to return a 4.00 RFC8768 Section 3 */
2936         coap_log_info("Invalid Hop Limit\n");
2937         resp = 400;
2938         goto fail_response;
2939       }
2940       hop_limit--;
2941       coap_update_option(pdu, COAP_OPTION_HOP_LIMIT,
2942                          coap_encode_var_safe8(buf, sizeof(buf), hop_limit),
2943                          buf);
2944     }
2945   }
2946 
2947   uri_path = coap_get_uri_path(pdu);
2948   if (!uri_path)
2949     return;
2950 
2951   if (!is_proxy_uri && !is_proxy_scheme) {
2952     /* try to find the resource from the request URI */
2953     coap_str_const_t uri_path_c = { uri_path->length, uri_path->s };
2954     resource = coap_get_resource_from_uri_path(context, &uri_path_c);
2955   }
2956 
2957   if ((resource == NULL) || (resource->is_unknown == 1) ||
2958       (resource->is_proxy_uri == 1)) {
2959     /* The resource was not found or there is an unexpected match against the
2960      * resource defined for handling unknown or proxy URIs.
2961      */
2962     if (resource != NULL)
2963       /* Close down unexpected match */
2964       resource = NULL;
2965     /*
2966      * Check if the request URI happens to be the well-known URI, or if the
2967      * unknown resource handler is defined, a PUT or optionally other methods,
2968      * if configured, for the unknown handler.
2969      *
2970      * if a PROXY URI/Scheme request and proxy URI handler defined, call the
2971      *  proxy URI handler
2972      *
2973      * else if well-known URI generate a default response
2974      *
2975      * else if unknown URI handler defined, call the unknown
2976      *  URI handler (to allow for potential generation of resource
2977      *  [RFC7272 5.8.3]) if the appropriate method is defined.
2978      *
2979      * else if DELETE return 2.02 (RFC7252: 5.8.4.  DELETE)
2980      *
2981      * else return 4.04 */
2982 
2983     if (is_proxy_uri || is_proxy_scheme) {
2984       resource = context->proxy_uri_resource;
2985     } else if (coap_string_equal(uri_path, &coap_default_uri_wellknown)) {
2986       /* request for .well-known/core */
2987       resource = &resource_uri_wellknown;
2988     } else if ((context->unknown_resource != NULL) &&
2989                ((size_t)pdu->code - 1 <
2990                 (sizeof(resource->handler) / sizeof(coap_method_handler_t))) &&
2991                (context->unknown_resource->handler[pdu->code - 1])) {
2992       /*
2993        * The unknown_resource can be used to handle undefined resources
2994        * for a PUT request and can support any other registered handler
2995        * defined for it
2996        * Example set up code:-
2997        *   r = coap_resource_unknown_init(hnd_put_unknown);
2998        *   coap_register_request_handler(r, COAP_REQUEST_POST,
2999        *                                 hnd_post_unknown);
3000        *   coap_register_request_handler(r, COAP_REQUEST_GET,
3001        *                                 hnd_get_unknown);
3002        *   coap_register_request_handler(r, COAP_REQUEST_DELETE,
3003        *                                 hnd_delete_unknown);
3004        *   coap_add_resource(ctx, r);
3005        *
3006        * Note: It is not possible to observe the unknown_resource, a separate
3007        *       resource must be created (by PUT or POST) which has a GET
3008        *       handler to be observed
3009        */
3010       resource = context->unknown_resource;
3011     } else if (pdu->code == COAP_REQUEST_CODE_DELETE) {
3012       /*
3013        * Request for DELETE on non-existant resource (RFC7252: 5.8.4.  DELETE)
3014        */
3015       coap_log_debug("request for unknown resource '%*.*s',"
3016                      " return 2.02\n",
3017                      (int)uri_path->length,
3018                      (int)uri_path->length,
3019                      uri_path->s);
3020       resp = 202;
3021       goto fail_response;
3022     } else { /* request for any another resource, return 4.04 */
3023 
3024       coap_log_debug("request for unknown resource '%*.*s', return 4.04\n",
3025                      (int)uri_path->length, (int)uri_path->length, uri_path->s);
3026       resp = 404;
3027       goto fail_response;
3028     }
3029 
3030   }
3031 
3032 #if COAP_OSCORE_SUPPORT
3033   if ((resource->flags & COAP_RESOURCE_FLAGS_OSCORE_ONLY) && !session->oscore_encryption) {
3034     coap_log_debug("request for OSCORE only resource '%*.*s', return 4.04\n",
3035                    (int)uri_path->length, (int)uri_path->length, uri_path->s);
3036     resp = 401;
3037     goto fail_response;
3038   }
3039 #endif /* COAP_OSCORE_SUPPORT */
3040   if (resource->is_unknown == 0 && resource->is_proxy_uri == 0) {
3041     /* Check for existing resource and If-Non-Match */
3042     opt = coap_check_option(pdu, COAP_OPTION_IF_NONE_MATCH, &opt_iter);
3043     if (opt) {
3044       resp = 412;
3045       goto fail_response;
3046     }
3047   }
3048 
3049   /* the resource was found, check if there is a registered handler */
3050   if ((size_t)pdu->code - 1 <
3051       sizeof(resource->handler) / sizeof(coap_method_handler_t))
3052     h = resource->handler[pdu->code - 1];
3053 
3054   if (h == NULL) {
3055     resp = 405;
3056     goto fail_response;
3057   }
3058   if (pdu->code == COAP_REQUEST_CODE_FETCH) {
3059     opt = coap_check_option(pdu, COAP_OPTION_CONTENT_FORMAT, &opt_iter);
3060     if (opt == NULL) {
3061       /* RFC 8132 2.3.1 */
3062       resp = 415;
3063       goto fail_response;
3064     }
3065   }
3066   if (context->mcast_per_resource &&
3067       (resource->flags & COAP_RESOURCE_FLAGS_HAS_MCAST_SUPPORT) == 0 &&
3068       coap_is_mcast(&session->addr_info.local)) {
3069     resp = 405;
3070     goto fail_response;
3071   }
3072 
3073   response = coap_pdu_init(pdu->type == COAP_MESSAGE_CON ?
3074                            COAP_MESSAGE_ACK : COAP_MESSAGE_NON,
3075                            0, pdu->mid, coap_session_max_pdu_size(session));
3076   if (!response) {
3077     coap_log_err("could not create response PDU\n");
3078     resp = 500;
3079     goto fail_response;
3080   }
3081   response->session = session;
3082 #if COAP_ASYNC_SUPPORT
3083   /* If handling a separate response, need CON, not ACK response */
3084   if (async && pdu->type == COAP_MESSAGE_CON)
3085     response->type = COAP_MESSAGE_CON;
3086 #endif /* COAP_ASYNC_SUPPORT */
3087 
3088   if (!coap_add_token(response, pdu->actual_token.length,
3089                       pdu->actual_token.s)) {
3090     resp = 500;
3091     goto fail_response;
3092   }
3093 
3094   query = coap_get_query(pdu);
3095 
3096   /* check for Observe option RFC7641 and RFC8132 */
3097   if (resource->observable &&
3098       (pdu->code == COAP_REQUEST_CODE_GET ||
3099        pdu->code == COAP_REQUEST_CODE_FETCH)) {
3100     observe = coap_check_option(pdu, COAP_OPTION_OBSERVE, &opt_iter);
3101   }
3102 
3103   /*
3104    * See if blocks need to be aggregated or next requests sent off
3105    * before invoking application request handler
3106    */
3107   if (session->block_mode & COAP_BLOCK_USE_LIBCOAP) {
3108     uint8_t block_mode = session->block_mode;
3109 
3110     if (pdu->code == COAP_REQUEST_CODE_FETCH ||
3111         resource->flags & COAP_RESOURCE_FLAGS_FORCE_SINGLE_BODY)
3112       session->block_mode |= COAP_BLOCK_SINGLE_BODY;
3113     if (coap_handle_request_put_block(context, session, pdu, response,
3114                                       resource, uri_path, observe,
3115                                       &added_block, &free_lg_srcv)) {
3116       session->block_mode = block_mode;
3117       goto skip_handler;
3118     }
3119     session->block_mode = block_mode;
3120 
3121     if (coap_handle_request_send_block(session, pdu, response, resource,
3122                                        query)) {
3123 #if COAP_Q_BLOCK_SUPPORT
3124       lg_xmit_ctrl = 1;
3125 #endif /* COAP_Q_BLOCK_SUPPORT */
3126       goto skip_handler;
3127     }
3128   }
3129 
3130   if (observe) {
3131     observe_action =
3132         coap_decode_var_bytes(coap_opt_value(observe),
3133                               coap_opt_length(observe));
3134 
3135     if (observe_action == COAP_OBSERVE_ESTABLISH) {
3136       coap_subscription_t *subscription;
3137 
3138       if (coap_get_block_b(session, pdu, COAP_OPTION_BLOCK2, &block)) {
3139         if (block.num != 0) {
3140           response->code = COAP_RESPONSE_CODE(400);
3141           goto skip_handler;
3142         }
3143 #if COAP_Q_BLOCK_SUPPORT
3144       } else if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK2,
3145                                   &block)) {
3146         if (block.num != 0) {
3147           response->code = COAP_RESPONSE_CODE(400);
3148           goto skip_handler;
3149         }
3150 #endif /* COAP_Q_BLOCK_SUPPORT */
3151       }
3152       subscription = coap_add_observer(resource, session, &pdu->actual_token,
3153                                        pdu);
3154       if (subscription) {
3155         uint8_t buf[4];
3156 
3157         coap_touch_observer(context, session, &pdu->actual_token);
3158         coap_add_option_internal(response, COAP_OPTION_OBSERVE,
3159                                  coap_encode_var_safe(buf, sizeof(buf),
3160                                                       resource->observe),
3161                                  buf);
3162       }
3163     } else if (observe_action == COAP_OBSERVE_CANCEL) {
3164       coap_delete_observer(resource, session, &pdu->actual_token);
3165     } else {
3166       coap_log_info("observe: unexpected action %d\n", observe_action);
3167     }
3168   }
3169 
3170   /* TODO for non-proxy requests */
3171   if (resource == context->proxy_uri_resource &&
3172       COAP_PROTO_NOT_RELIABLE(session->proto) &&
3173       pdu->type == COAP_MESSAGE_CON) {
3174     /* Make the proxy response separate and fix response later */
3175     send_early_empty_ack = 1;
3176   }
3177   if (send_early_empty_ack) {
3178     coap_send_ack(session, pdu);
3179     if (pdu->mid == session->last_con_mid) {
3180       /* request has already been processed - do not process it again */
3181       coap_log_debug("Duplicate request with mid=0x%04x - not processed\n",
3182                      pdu->mid);
3183       goto drop_it_no_debug;
3184     }
3185     session->last_con_mid = pdu->mid;
3186   }
3187 #if COAP_WITH_OBSERVE_PERSIST
3188   /* If we are maintaining Observe persist */
3189   if (resource == context->unknown_resource) {
3190     context->unknown_pdu = pdu;
3191     context->unknown_session = session;
3192   } else
3193     context->unknown_pdu = NULL;
3194 #endif /* COAP_WITH_OBSERVE_PERSIST */
3195 
3196   /*
3197    * Call the request handler with everything set up
3198    */
3199   coap_log_debug("call custom handler for resource '%*.*s' (3)\n",
3200                  (int)resource->uri_path->length, (int)resource->uri_path->length,
3201                  resource->uri_path->s);
3202   h(resource, session, pdu, query, response);
3203 
3204   /* Check if lg_xmit generated and update PDU code if so */
3205   coap_check_code_lg_xmit(session, pdu, response, resource, query);
3206 
3207   if (free_lg_srcv) {
3208     /* Check to see if the server is doing a 4.01 + Echo response */
3209     if (response->code ==  COAP_RESPONSE_CODE(401) &&
3210         coap_check_option(response, COAP_OPTION_ECHO, &opt_iter)) {
3211       /* Need to keep lg_srcv around for client's response */
3212     } else {
3213       LL_DELETE(session->lg_srcv, free_lg_srcv);
3214       coap_block_delete_lg_srcv(session, free_lg_srcv);
3215     }
3216   }
3217   if (added_block && COAP_RESPONSE_CLASS(response->code) == 2) {
3218     /* Just in case, as there are more to go */
3219     response->code = COAP_RESPONSE_CODE(231);
3220   }
3221 
3222 skip_handler:
3223   if (send_early_empty_ack &&
3224       response->type == COAP_MESSAGE_ACK) {
3225     /* Response is now separate - convert to CON as needed */
3226     response->type = COAP_MESSAGE_CON;
3227     /* Check for empty ACK - need to drop as already sent */
3228     if (response->code == 0) {
3229       goto drop_it_no_debug;
3230     }
3231   }
3232   respond = no_response(pdu, response, session, resource);
3233   if (respond != RESPONSE_DROP) {
3234 #if (COAP_MAX_LOGGING_LEVEL >= _COAP_LOG_DEBUG)
3235     coap_mid_t mid = pdu->mid;
3236 #endif
3237     if (COAP_RESPONSE_CLASS(response->code) != 2) {
3238       if (observe) {
3239         coap_remove_option(response, COAP_OPTION_OBSERVE);
3240       }
3241     }
3242     if (COAP_RESPONSE_CLASS(response->code) > 2) {
3243       if (observe)
3244         coap_delete_observer(resource, session, &pdu->actual_token);
3245       if (added_block)
3246         coap_remove_option(response, COAP_OPTION_BLOCK1);
3247     }
3248 
3249     /* If original request contained a token, and the registered
3250      * application handler made no changes to the response, then
3251      * this is an empty ACK with a token, which is a malformed
3252      * PDU */
3253     if ((response->type == COAP_MESSAGE_ACK)
3254         && (response->code == 0)) {
3255       /* Remove token from otherwise-empty acknowledgment PDU */
3256       response->actual_token.length = 0;
3257       response->e_token_length = 0;
3258       response->used_size = 0;
3259       response->data = NULL;
3260     }
3261 
3262     if (!coap_is_mcast(&session->addr_info.local) ||
3263         (context->mcast_per_resource &&
3264          resource &&
3265          (resource->flags & COAP_RESOURCE_FLAGS_LIB_DIS_MCAST_DELAYS))) {
3266       /* No delays to response */
3267 #if COAP_Q_BLOCK_SUPPORT
3268       if (session->block_mode & COAP_BLOCK_USE_LIBCOAP &&
3269           !lg_xmit_ctrl && response->code == COAP_RESPONSE_CODE(205) &&
3270           coap_get_block_b(session, response, COAP_OPTION_Q_BLOCK2, &block) &&
3271           block.m) {
3272         if (coap_send_q_block2(session, resource, query, pdu->code, block,
3273                                response,
3274                                COAP_SEND_INC_PDU) == COAP_INVALID_MID)
3275           coap_log_debug("cannot send response for mid=0x%x\n", mid);
3276         response = NULL;
3277         if (query)
3278           coap_delete_string(query);
3279         goto finish;
3280       }
3281 #endif /* COAP_Q_BLOCK_SUPPORT */
3282       if (coap_send_internal(session, response) == COAP_INVALID_MID) {
3283         coap_log_debug("cannot send response for mid=0x%04x\n", mid);
3284       }
3285     } else {
3286       /* Need to delay mcast response */
3287       coap_queue_t *node = coap_new_node();
3288       uint8_t r;
3289       coap_tick_t delay;
3290 
3291       if (!node) {
3292         coap_log_debug("mcast delay: insufficient memory\n");
3293         goto drop_it_no_debug;
3294       }
3295       if (!coap_pdu_encode_header(response, session->proto)) {
3296         coap_delete_node(node);
3297         goto drop_it_no_debug;
3298       }
3299 
3300       node->id = response->mid;
3301       node->pdu = response;
3302       node->is_mcast = 1;
3303       coap_prng(&r, sizeof(r));
3304       delay = (COAP_DEFAULT_LEISURE_TICKS(session) * r) / 256;
3305       coap_log_debug("   %s: mid=0x%04x: mcast response delayed for %u.%03u secs\n",
3306                      coap_session_str(session),
3307                      response->mid,
3308                      (unsigned int)(delay / COAP_TICKS_PER_SECOND),
3309                      (unsigned int)((delay % COAP_TICKS_PER_SECOND) *
3310                                     1000 / COAP_TICKS_PER_SECOND));
3311       node->timeout = (unsigned int)delay;
3312       /* Use this to delay transmission */
3313       coap_wait_ack(session->context, session, node);
3314     }
3315   } else {
3316     coap_log_debug("   %s: mid=0x%04x: response dropped\n",
3317                    coap_session_str(session),
3318                    response->mid);
3319     coap_show_pdu(COAP_LOG_DEBUG, response);
3320 drop_it_no_debug:
3321     coap_delete_pdu(response);
3322   }
3323   if (query)
3324     coap_delete_string(query);
3325 #if COAP_Q_BLOCK_SUPPORT
3326   if (coap_get_block_b(session, pdu, COAP_OPTION_Q_BLOCK1, &block)) {
3327     if (COAP_PROTO_RELIABLE(session->proto)) {
3328       if (block.m) {
3329         /* All of the sequence not in yet */
3330         goto finish;
3331       }
3332     } else if (pdu->type == COAP_MESSAGE_NON) {
3333       /* More to go and not at a payload break */
3334       if (block.m && ((block.num + 1) % COAP_MAX_PAYLOADS(session))) {
3335         goto finish;
3336       }
3337     }
3338   }
3339 #endif /* COAP_Q_BLOCK_SUPPORT */
3340 
3341 #if COAP_Q_BLOCK_SUPPORT
3342 finish:
3343 #endif /* COAP_Q_BLOCK_SUPPORT */
3344   coap_delete_string(uri_path);
3345   return;
3346 
3347 fail_response:
3348   coap_delete_pdu(response);
3349   response =
3350       coap_new_error_response(pdu, COAP_RESPONSE_CODE(resp),
3351                               &opt_filter);
3352   if (response)
3353     goto skip_handler;
3354   coap_delete_string(uri_path);
3355 }
3356 #endif /* COAP_SERVER_SUPPORT */
3357 
3358 #if COAP_CLIENT_SUPPORT
3359 static void
3360 handle_response(coap_context_t *context, coap_session_t *session,
3361                 coap_pdu_t *sent, coap_pdu_t *rcvd) {
3362 
3363   /* In a lossy context, the ACK of a separate response may have
3364    * been lost, so we need to stop retransmitting requests with the
3365    * same token. Matching on token potentially containing ext length bytes.
3366    */
3367   if (rcvd->type != COAP_MESSAGE_ACK)
3368     coap_cancel_all_messages(context, session, &rcvd->actual_token);
3369 
3370   /* Check for message duplication */
3371   if (COAP_PROTO_NOT_RELIABLE(session->proto)) {
3372     if (rcvd->type == COAP_MESSAGE_CON) {
3373       if (rcvd->mid == session->last_con_mid) {
3374         /* Duplicate response */
3375         return;
3376       }
3377       session->last_con_mid = rcvd->mid;
3378     } else if (rcvd->type == COAP_MESSAGE_ACK) {
3379       if (rcvd->mid == session->last_ack_mid) {
3380         /* Duplicate response */
3381         return;
3382       }
3383       session->last_ack_mid = rcvd->mid;
3384     }
3385   }
3386   /* Check to see if checking out extended token support */
3387   if (session->max_token_checked == COAP_EXT_T_CHECKING &&
3388       session->remote_test_mid == rcvd->mid) {
3389 
3390     if (rcvd->actual_token.length != session->max_token_size ||
3391         rcvd->code == COAP_RESPONSE_CODE(400) ||
3392         rcvd->code == COAP_RESPONSE_CODE(503)) {
3393       coap_log_debug("Extended Token requested size support not available\n");
3394       session->max_token_size = COAP_TOKEN_DEFAULT_MAX;
3395     } else {
3396       coap_log_debug("Extended Token support available\n");
3397     }
3398     session->max_token_checked = COAP_EXT_T_CHECKED;
3399     session->doing_first = 0;
3400     return;
3401   }
3402 #if COAP_Q_BLOCK_SUPPORT
3403   /* Check to see if checking out Q-Block support */
3404   if (session->block_mode & COAP_BLOCK_PROBE_Q_BLOCK &&
3405       session->remote_test_mid == rcvd->mid) {
3406     if (rcvd->code == COAP_RESPONSE_CODE(402)) {
3407       coap_log_debug("Q-Block support not available\n");
3408       set_block_mode_drop_q(session->block_mode);
3409     } else {
3410       coap_block_b_t qblock;
3411 
3412       if (coap_get_block_b(session, rcvd, COAP_OPTION_Q_BLOCK2, &qblock)) {
3413         coap_log_debug("Q-Block support available\n");
3414         set_block_mode_has_q(session->block_mode);
3415       } else {
3416         coap_log_debug("Q-Block support not available\n");
3417         set_block_mode_drop_q(session->block_mode);
3418       }
3419     }
3420     session->doing_first = 0;
3421     return;
3422   }
3423 #endif /* COAP_Q_BLOCK_SUPPORT */
3424 
3425   if (session->block_mode & COAP_BLOCK_USE_LIBCOAP) {
3426     /* See if need to send next block to server */
3427     if (coap_handle_response_send_block(session, sent, rcvd)) {
3428       /* Next block transmitted, no need to inform app */
3429       coap_send_ack(session, rcvd);
3430       return;
3431     }
3432 
3433     /* Need to see if needing to request next block */
3434     if (coap_handle_response_get_block(context, session, sent, rcvd,
3435                                        COAP_RECURSE_OK)) {
3436       /* Next block transmitted, ack sent no need to inform app */
3437       return;
3438     }
3439   }
3440   if (session->doing_first)
3441     session->doing_first = 0;
3442 
3443   /* Call application-specific response handler when available. */
3444   if (context->response_handler) {
3445     if (context->response_handler(session, sent, rcvd,
3446                                   rcvd->mid) == COAP_RESPONSE_FAIL)
3447       coap_send_rst(session, rcvd);
3448     else
3449       coap_send_ack(session, rcvd);
3450   } else {
3451     coap_send_ack(session, rcvd);
3452   }
3453 }
3454 #endif /* COAP_CLIENT_SUPPORT */
3455 
3456 #if !COAP_DISABLE_TCP
3457 static void
3458 handle_signaling(coap_context_t *context, coap_session_t *session,
3459                  coap_pdu_t *pdu) {
3460   coap_opt_iterator_t opt_iter;
3461   coap_opt_t *option;
3462   int set_mtu = 0;
3463 
3464   coap_option_iterator_init(pdu, &opt_iter, COAP_OPT_ALL);
3465 
3466   if (pdu->code == COAP_SIGNALING_CODE_CSM) {
3467     if (session->max_token_checked == COAP_EXT_T_NOT_CHECKED) {
3468       session->max_token_size = COAP_TOKEN_DEFAULT_MAX;
3469     }
3470     while ((option = coap_option_next(&opt_iter))) {
3471       if (opt_iter.number == COAP_SIGNALING_OPTION_MAX_MESSAGE_SIZE) {
3472         coap_session_set_mtu(session, coap_decode_var_bytes(coap_opt_value(option),
3473                                                             coap_opt_length(option)));
3474         set_mtu = 1;
3475       } else if (opt_iter.number == COAP_SIGNALING_OPTION_BLOCK_WISE_TRANSFER) {
3476         session->csm_block_supported = 1;
3477       } else if (opt_iter.number == COAP_SIGNALING_OPTION_EXTENDED_TOKEN_LENGTH) {
3478         session->max_token_size =
3479             coap_decode_var_bytes(coap_opt_value(option),
3480                                   coap_opt_length(option));
3481         if (session->max_token_size < COAP_TOKEN_DEFAULT_MAX)
3482           session->max_token_size = COAP_TOKEN_DEFAULT_MAX;
3483         else if (session->max_token_size > COAP_TOKEN_EXT_MAX)
3484           session->max_token_size = COAP_TOKEN_EXT_MAX;
3485         session->max_token_checked = COAP_EXT_T_CHECKED;
3486       }
3487     }
3488     if (set_mtu) {
3489       if (session->mtu > COAP_BERT_BASE && session->csm_block_supported)
3490         session->csm_bert_rem_support = 1;
3491       else
3492         session->csm_bert_rem_support = 0;
3493     }
3494     if (session->state == COAP_SESSION_STATE_CSM)
3495       coap_session_connected(session);
3496   } else if (pdu->code == COAP_SIGNALING_CODE_PING) {
3497     coap_pdu_t *pong = coap_pdu_init(COAP_MESSAGE_CON, COAP_SIGNALING_CODE_PONG, 0, 1);
3498     if (context->ping_handler) {
3499       context->ping_handler(session, pdu, pdu->mid);
3500     }
3501     if (pong) {
3502       coap_add_option_internal(pong, COAP_SIGNALING_OPTION_CUSTODY, 0, NULL);
3503       coap_send_internal(session, pong);
3504     }
3505   } else if (pdu->code == COAP_SIGNALING_CODE_PONG) {
3506     session->last_pong = session->last_rx_tx;
3507     if (context->pong_handler) {
3508       context->pong_handler(session, pdu, pdu->mid);
3509     }
3510   } else if (pdu->code == COAP_SIGNALING_CODE_RELEASE
3511              || pdu->code == COAP_SIGNALING_CODE_ABORT) {
3512     coap_session_disconnected(session, COAP_NACK_RST);
3513   }
3514 }
3515 #endif /* !COAP_DISABLE_TCP */
3516 
3517 static int
3518 check_token_size(coap_session_t *session, const coap_pdu_t *pdu) {
3519   if (COAP_PDU_IS_REQUEST(pdu) &&
3520       pdu->actual_token.length >
3521       (session->type == COAP_SESSION_TYPE_CLIENT ?
3522        session->max_token_size : session->context->max_token_size)) {
3523     /* https://rfc-editor.org/rfc/rfc8974#section-2.2.2 */
3524     if (session->max_token_size > COAP_TOKEN_DEFAULT_MAX) {
3525       coap_opt_filter_t opt_filter;
3526       coap_pdu_t *response;
3527 
3528       memset(&opt_filter, 0, sizeof(coap_opt_filter_t));
3529       response = coap_new_error_response(pdu, COAP_RESPONSE_CODE(400),
3530                                          &opt_filter);
3531       if (!response) {
3532         coap_log_warn("coap_dispatch: cannot create error response\n");
3533       } else {
3534         /*
3535          * Note - have to leave in oversize token as per
3536          * https://rfc-editor.org/rfc/rfc7252#section-5.3.1
3537          */
3538         if (coap_send_internal(session, response) == COAP_INVALID_MID)
3539           coap_log_warn("coap_dispatch: error sending response\n");
3540       }
3541     } else {
3542       /* Indicate no extended token support */
3543       coap_send_rst(session, pdu);
3544     }
3545     return 0;
3546   }
3547   return 1;
3548 }
3549 
3550 void
3551 coap_dispatch(coap_context_t *context, coap_session_t *session,
3552               coap_pdu_t *pdu) {
3553   coap_queue_t *sent = NULL;
3554   coap_pdu_t *response;
3555   coap_opt_filter_t opt_filter;
3556   int is_ping_rst;
3557   int packet_is_bad = 0;
3558 #if COAP_OSCORE_SUPPORT
3559   coap_opt_iterator_t opt_iter;
3560   coap_pdu_t *dec_pdu = NULL;
3561 #endif /* COAP_OSCORE_SUPPORT */
3562   int is_ext_token_rst;
3563 
3564   pdu->session = session;
3565   coap_show_pdu(COAP_LOG_DEBUG, pdu);
3566 
3567   memset(&opt_filter, 0, sizeof(coap_opt_filter_t));
3568 
3569 #if COAP_OSCORE_SUPPORT
3570   if (!COAP_PDU_IS_SIGNALING(pdu) &&
3571       coap_option_check_critical(session, pdu, &opt_filter) == 0) {
3572     if (pdu->type == COAP_MESSAGE_NON) {
3573       coap_send_rst(session, pdu);
3574       goto cleanup;
3575     } else if (pdu->type == COAP_MESSAGE_CON) {
3576       if (COAP_PDU_IS_REQUEST(pdu)) {
3577         response =
3578             coap_new_error_response(pdu, COAP_RESPONSE_CODE(402), &opt_filter);
3579 
3580         if (!response) {
3581           coap_log_warn("coap_dispatch: cannot create error response\n");
3582         } else {
3583           if (coap_send_internal(session, response) == COAP_INVALID_MID)
3584             coap_log_warn("coap_dispatch: error sending response\n");
3585         }
3586       } else {
3587         coap_send_rst(session, pdu);
3588       }
3589     }
3590     goto cleanup;
3591   }
3592 
3593   if (coap_check_option(pdu, COAP_OPTION_OSCORE, &opt_iter) != NULL) {
3594     int decrypt = 1;
3595 #if COAP_SERVER_SUPPORT
3596     coap_opt_t *opt;
3597     coap_resource_t *resource;
3598     coap_uri_t uri;
3599 #endif /* COAP_SERVER_SUPPORT */
3600 
3601     if (COAP_PDU_IS_RESPONSE(pdu) && !session->oscore_encryption)
3602       decrypt = 0;
3603 
3604 #if COAP_SERVER_SUPPORT
3605     if (decrypt && COAP_PDU_IS_REQUEST(pdu) &&
3606         coap_check_option(pdu, COAP_OPTION_PROXY_SCHEME, &opt_iter) != NULL &&
3607         (opt = coap_check_option(pdu, COAP_OPTION_URI_HOST, &opt_iter))
3608         != NULL) {
3609       /* Need to check whether this is a direct or proxy session */
3610       memset(&uri, 0, sizeof(uri));
3611       uri.host.length = coap_opt_length(opt);
3612       uri.host.s = coap_opt_value(opt);
3613       resource = context->proxy_uri_resource;
3614       if (uri.host.length && resource && resource->proxy_name_count &&
3615           resource->proxy_name_list) {
3616         size_t i;
3617         for (i = 0; i < resource->proxy_name_count; i++) {
3618           if (coap_string_equal(&uri.host, resource->proxy_name_list[i])) {
3619             break;
3620           }
3621         }
3622         if (i == resource->proxy_name_count) {
3623           /* This server is not hosting the proxy connection endpoint */
3624           decrypt = 0;
3625         }
3626       }
3627     }
3628 #endif /* COAP_SERVER_SUPPORT */
3629     if (decrypt) {
3630       /* find message id in sendqueue to stop retransmission and get sent */
3631       coap_remove_from_queue(&context->sendqueue, session, pdu->mid, &sent);
3632       if ((dec_pdu = coap_oscore_decrypt_pdu(session, pdu)) == NULL) {
3633         if (session->recipient_ctx == NULL ||
3634             session->recipient_ctx->initial_state == 0) {
3635           coap_log_warn("OSCORE: PDU could not be decrypted\n");
3636         }
3637         coap_delete_node(sent);
3638         return;
3639       } else {
3640         session->oscore_encryption = 1;
3641         pdu = dec_pdu;
3642       }
3643       coap_log_debug("Decrypted PDU\n");
3644       coap_show_pdu(COAP_LOG_DEBUG, pdu);
3645     }
3646   }
3647 #endif /* COAP_OSCORE_SUPPORT */
3648 
3649   switch (pdu->type) {
3650   case COAP_MESSAGE_ACK:
3651     /* find message id in sendqueue to stop retransmission */
3652     coap_remove_from_queue(&context->sendqueue, session, pdu->mid, &sent);
3653 
3654     if (sent && session->con_active) {
3655       session->con_active--;
3656       if (session->state == COAP_SESSION_STATE_ESTABLISHED)
3657         /* Flush out any entries on session->delayqueue */
3658         coap_session_connected(session);
3659     }
3660     if (coap_option_check_critical(session, pdu, &opt_filter) == 0) {
3661       packet_is_bad = 1;
3662       goto cleanup;
3663     }
3664 
3665 #if COAP_SERVER_SUPPORT
3666     /* if sent code was >= 64 the message might have been a
3667      * notification. Then, we must flag the observer to be alive
3668      * by setting obs->fail_cnt = 0. */
3669     if (sent && COAP_RESPONSE_CLASS(sent->pdu->code) == 2) {
3670       coap_touch_observer(context, sent->session, &sent->pdu->actual_token);
3671     }
3672 #endif /* COAP_SERVER_SUPPORT */
3673 
3674     if (pdu->code == 0) {
3675 #if COAP_Q_BLOCK_SUPPORT
3676       if (sent) {
3677         coap_block_b_t block;
3678 
3679         if (sent->pdu->type == COAP_MESSAGE_CON &&
3680             COAP_PROTO_NOT_RELIABLE(session->proto) &&
3681             coap_get_block_b(session, sent->pdu,
3682                              COAP_PDU_IS_REQUEST(sent->pdu) ?
3683                              COAP_OPTION_Q_BLOCK1 : COAP_OPTION_Q_BLOCK2,
3684                              &block)) {
3685           if (block.m) {
3686 #if COAP_CLIENT_SUPPORT
3687             if (COAP_PDU_IS_REQUEST(sent->pdu))
3688               coap_send_q_block1(session, block, sent->pdu,
3689                                  COAP_SEND_SKIP_PDU);
3690 #endif /* COAP_CLIENT_SUPPORT */
3691             if (COAP_PDU_IS_RESPONSE(sent->pdu))
3692               coap_send_q_blocks(session, sent->pdu->lg_xmit, block,
3693                                  sent->pdu, COAP_SEND_SKIP_PDU);
3694           }
3695         }
3696       }
3697 #endif /* COAP_Q_BLOCK_SUPPORT */
3698       /* an empty ACK needs no further handling */
3699       goto cleanup;
3700     }
3701 
3702     break;
3703 
3704   case COAP_MESSAGE_RST:
3705     /* We have sent something the receiver disliked, so we remove
3706      * not only the message id but also the subscriptions we might
3707      * have. */
3708     is_ping_rst = 0;
3709     if (pdu->mid == session->last_ping_mid &&
3710         context->ping_timeout && session->last_ping > 0)
3711       is_ping_rst = 1;
3712 
3713 #if COAP_Q_BLOCK_SUPPORT
3714     /* Check to see if checking out Q-Block support */
3715     if (session->block_mode & COAP_BLOCK_PROBE_Q_BLOCK &&
3716         session->remote_test_mid == pdu->mid) {
3717       coap_log_debug("Q-Block support not available\n");
3718       set_block_mode_drop_q(session->block_mode);
3719     }
3720 #endif /* COAP_Q_BLOCK_SUPPORT */
3721 
3722     /* Check to see if checking out extended token support */
3723     is_ext_token_rst = 0;
3724     if (session->max_token_checked == COAP_EXT_T_CHECKING &&
3725         session->remote_test_mid == pdu->mid) {
3726       coap_log_debug("Extended Token support not available\n");
3727       session->max_token_size = COAP_TOKEN_DEFAULT_MAX;
3728       session->max_token_checked = COAP_EXT_T_CHECKED;
3729       session->doing_first = 0;
3730       is_ext_token_rst = 1;
3731     }
3732 
3733     if (!is_ping_rst && !is_ext_token_rst)
3734       coap_log_alert("got RST for mid=0x%04x\n", pdu->mid);
3735 
3736     if (session->con_active) {
3737       session->con_active--;
3738       if (session->state == COAP_SESSION_STATE_ESTABLISHED)
3739         /* Flush out any entries on session->delayqueue */
3740         coap_session_connected(session);
3741     }
3742 
3743     /* find message id in sendqueue to stop retransmission */
3744     coap_remove_from_queue(&context->sendqueue, session, pdu->mid, &sent);
3745 
3746     if (sent) {
3747       coap_cancel(context, sent);
3748 
3749       if (!is_ping_rst && !is_ext_token_rst) {
3750         if (sent->pdu->type==COAP_MESSAGE_CON && context->nack_handler) {
3751           coap_check_update_token(sent->session, sent->pdu);
3752           context->nack_handler(sent->session, sent->pdu,
3753                                 COAP_NACK_RST, sent->id);
3754         }
3755       } else if (is_ping_rst) {
3756         if (context->pong_handler) {
3757           context->pong_handler(session, pdu, pdu->mid);
3758         }
3759         session->last_pong = session->last_rx_tx;
3760         session->last_ping_mid = COAP_INVALID_MID;
3761       }
3762     } else {
3763 #if COAP_SERVER_SUPPORT
3764       /* Need to check is there is a subscription active and delete it */
3765       RESOURCES_ITER(context->resources, r) {
3766         coap_subscription_t *obs, *tmp;
3767         LL_FOREACH_SAFE(r->subscribers, obs, tmp) {
3768           if (obs->pdu->mid == pdu->mid && obs->session == session) {
3769             /* Need to do this now as session may get de-referenced */
3770             coap_session_reference(session);
3771             coap_delete_observer(r, session, &obs->pdu->actual_token);
3772             if (context->nack_handler)
3773               context->nack_handler(session, NULL, COAP_NACK_RST, pdu->mid);
3774             coap_session_release(session);
3775             goto cleanup;
3776           }
3777         }
3778       }
3779 #endif /* COAP_SERVER_SUPPORT */
3780       if (context->nack_handler)
3781         context->nack_handler(session, NULL, COAP_NACK_RST, pdu->mid);
3782     }
3783     goto cleanup;
3784 
3785   case COAP_MESSAGE_NON:
3786     /* find transaction in sendqueue in case large response */
3787     coap_remove_from_queue(&context->sendqueue, session, pdu->mid, &sent);
3788     /* check for unknown critical options */
3789     if (coap_option_check_critical(session, pdu, &opt_filter) == 0) {
3790       packet_is_bad = 1;
3791       coap_send_rst(session, pdu);
3792       goto cleanup;
3793     }
3794     if (!check_token_size(session, pdu)) {
3795       goto cleanup;
3796     }
3797     break;
3798 
3799   case COAP_MESSAGE_CON:        /* check for unknown critical options */
3800     if (!COAP_PDU_IS_SIGNALING(pdu) &&
3801         coap_option_check_critical(session, pdu, &opt_filter) == 0) {
3802       packet_is_bad = 1;
3803       if (COAP_PDU_IS_REQUEST(pdu)) {
3804         response =
3805             coap_new_error_response(pdu, COAP_RESPONSE_CODE(402), &opt_filter);
3806 
3807         if (!response) {
3808           coap_log_warn("coap_dispatch: cannot create error response\n");
3809         } else {
3810           if (coap_send_internal(session, response) == COAP_INVALID_MID)
3811             coap_log_warn("coap_dispatch: error sending response\n");
3812         }
3813       } else {
3814         coap_send_rst(session, pdu);
3815       }
3816       goto cleanup;
3817     }
3818     if (!check_token_size(session, pdu)) {
3819       goto cleanup;
3820     }
3821     break;
3822   default:
3823     break;
3824   }
3825 
3826   /* Pass message to upper layer if a specific handler was
3827     * registered for a request that should be handled locally. */
3828 #if !COAP_DISABLE_TCP
3829   if (COAP_PDU_IS_SIGNALING(pdu))
3830     handle_signaling(context, session, pdu);
3831   else
3832 #endif /* !COAP_DISABLE_TCP */
3833 #if COAP_SERVER_SUPPORT
3834     if (COAP_PDU_IS_REQUEST(pdu))
3835       handle_request(context, session, pdu);
3836     else
3837 #endif /* COAP_SERVER_SUPPORT */
3838 #if COAP_CLIENT_SUPPORT
3839       if (COAP_PDU_IS_RESPONSE(pdu))
3840         handle_response(context, session, sent ? sent->pdu : NULL, pdu);
3841       else
3842 #endif /* COAP_CLIENT_SUPPORT */
3843       {
3844         if (COAP_PDU_IS_EMPTY(pdu)) {
3845           if (context->ping_handler) {
3846             context->ping_handler(session, pdu, pdu->mid);
3847           }
3848         } else {
3849           packet_is_bad = 1;
3850         }
3851         coap_log_debug("dropped message with invalid code (%d.%02d)\n",
3852                        COAP_RESPONSE_CLASS(pdu->code),
3853                        pdu->code & 0x1f);
3854 
3855         if (!coap_is_mcast(&session->addr_info.local)) {
3856           if (COAP_PDU_IS_EMPTY(pdu)) {
3857             if (COAP_PROTO_NOT_RELIABLE(session->proto)) {
3858               coap_tick_t now;
3859               coap_ticks(&now);
3860               if (session->last_tx_rst + COAP_TICKS_PER_SECOND/4 < now) {
3861                 coap_send_message_type(session, pdu, COAP_MESSAGE_RST);
3862                 session->last_tx_rst = now;
3863               }
3864             }
3865           } else {
3866             coap_send_message_type(session, pdu, COAP_MESSAGE_RST);
3867           }
3868         }
3869       }
3870 
3871 cleanup:
3872   if (packet_is_bad) {
3873     if (sent) {
3874       if (context->nack_handler) {
3875         coap_check_update_token(session, sent->pdu);
3876         context->nack_handler(session, sent->pdu, COAP_NACK_BAD_RESPONSE, sent->id);
3877       }
3878     } else {
3879       coap_handle_event(context, COAP_EVENT_BAD_PACKET, session);
3880     }
3881   }
3882   coap_delete_node(sent);
3883 #if COAP_OSCORE_SUPPORT
3884   coap_delete_pdu(dec_pdu);
3885 #endif /* COAP_OSCORE_SUPPORT */
3886 }
3887 
3888 #if COAP_MAX_LOGGING_LEVEL >= _COAP_LOG_DEBUG
3889 static const char *
3890 coap_event_name(coap_event_t event) {
3891   switch (event) {
3892   case COAP_EVENT_DTLS_CLOSED:
3893     return "COAP_EVENT_DTLS_CLOSED";
3894   case COAP_EVENT_DTLS_CONNECTED:
3895     return "COAP_EVENT_DTLS_CONNECTED";
3896   case COAP_EVENT_DTLS_RENEGOTIATE:
3897     return "COAP_EVENT_DTLS_RENEGOTIATE";
3898   case COAP_EVENT_DTLS_ERROR:
3899     return "COAP_EVENT_DTLS_ERROR";
3900   case COAP_EVENT_TCP_CONNECTED:
3901     return "COAP_EVENT_TCP_CONNECTED";
3902   case COAP_EVENT_TCP_CLOSED:
3903     return "COAP_EVENT_TCP_CLOSED";
3904   case COAP_EVENT_TCP_FAILED:
3905     return "COAP_EVENT_TCP_FAILED";
3906   case COAP_EVENT_SESSION_CONNECTED:
3907     return "COAP_EVENT_SESSION_CONNECTED";
3908   case COAP_EVENT_SESSION_CLOSED:
3909     return "COAP_EVENT_SESSION_CLOSED";
3910   case COAP_EVENT_SESSION_FAILED:
3911     return "COAP_EVENT_SESSION_FAILED";
3912   case COAP_EVENT_PARTIAL_BLOCK:
3913     return "COAP_EVENT_PARTIAL_BLOCK";
3914   case COAP_EVENT_XMIT_BLOCK_FAIL:
3915     return "COAP_EVENT_XMIT_BLOCK_FAIL";
3916   case COAP_EVENT_SERVER_SESSION_NEW:
3917     return "COAP_EVENT_SERVER_SESSION_NEW";
3918   case COAP_EVENT_SERVER_SESSION_DEL:
3919     return "COAP_EVENT_SERVER_SESSION_DEL";
3920   case COAP_EVENT_BAD_PACKET:
3921     return "COAP_EVENT_BAD_PACKET";
3922   case COAP_EVENT_MSG_RETRANSMITTED:
3923     return "COAP_EVENT_MSG_RETRANSMITTED";
3924   case COAP_EVENT_OSCORE_DECRYPTION_FAILURE:
3925     return "COAP_EVENT_OSCORE_DECRYPTION_FAILURE";
3926   case COAP_EVENT_OSCORE_NOT_ENABLED:
3927     return "COAP_EVENT_OSCORE_NOT_ENABLED";
3928   case COAP_EVENT_OSCORE_NO_PROTECTED_PAYLOAD:
3929     return "COAP_EVENT_OSCORE_NO_PROTECTED_PAYLOAD";
3930   case COAP_EVENT_OSCORE_NO_SECURITY:
3931     return "COAP_EVENT_OSCORE_NO_SECURITY";
3932   case COAP_EVENT_OSCORE_INTERNAL_ERROR:
3933     return "COAP_EVENT_OSCORE_INTERNAL_ERROR";
3934   case COAP_EVENT_OSCORE_DECODE_ERROR:
3935     return "COAP_EVENT_OSCORE_DECODE_ERROR";
3936   case COAP_EVENT_WS_PACKET_SIZE:
3937     return "COAP_EVENT_WS_PACKET_SIZE";
3938   case COAP_EVENT_WS_CONNECTED:
3939     return "COAP_EVENT_WS_CONNECTED";
3940   case COAP_EVENT_WS_CLOSED:
3941     return "COAP_EVENT_WS_CLOSED";
3942   case COAP_EVENT_KEEPALIVE_FAILURE:
3943     return "COAP_EVENT_KEEPALIVE_FAILURE";
3944   default:
3945     return "???";
3946   }
3947 }
3948 #endif /* COAP_MAX_LOGGING_LEVEL >= _COAP_LOG_DEBUG */
3949 
3950 int
3951 coap_handle_event(coap_context_t *context, coap_event_t event, coap_session_t *session) {
3952   coap_log_debug("***EVENT: %s\n", coap_event_name(event));
3953 
3954   if (context->handle_event) {
3955     return context->handle_event(session, event);
3956   } else {
3957     return 0;
3958   }
3959 }
3960 
3961 int
3962 coap_can_exit(coap_context_t *context) {
3963   coap_session_t *s, *rtmp;
3964   if (!context)
3965     return 1;
3966   if (context->sendqueue)
3967     return 0;
3968 #if COAP_SERVER_SUPPORT
3969   coap_endpoint_t *ep;
3970 
3971   LL_FOREACH(context->endpoint, ep) {
3972     SESSIONS_ITER(ep->sessions, s, rtmp) {
3973       if (s->delayqueue)
3974         return 0;
3975       if (s->lg_xmit)
3976         return 0;
3977     }
3978   }
3979 #endif /* COAP_SERVER_SUPPORT */
3980 #if COAP_CLIENT_SUPPORT
3981   SESSIONS_ITER(context->sessions, s, rtmp) {
3982     if (s->delayqueue)
3983       return 0;
3984     if (s->lg_xmit)
3985       return 0;
3986   }
3987 #endif /* COAP_CLIENT_SUPPORT */
3988   return 1;
3989 }
3990 #if COAP_SERVER_SUPPORT
3991 #if COAP_ASYNC_SUPPORT
3992 coap_tick_t
3993 coap_check_async(coap_context_t *context, coap_tick_t now) {
3994   coap_tick_t next_due = 0;
3995   coap_async_t *async, *tmp;
3996 
3997   LL_FOREACH_SAFE(context->async_state, async, tmp) {
3998     if (async->delay != 0 && async->delay <= now) {
3999       /* Send off the request to the application */
4000       handle_request(context, async->session, async->pdu);
4001 
4002       /* Remove this async entry as it has now fired */
4003       coap_free_async(async->session, async);
4004     } else {
4005       if (next_due == 0 || next_due > async->delay - now)
4006         next_due = async->delay - now;
4007     }
4008   }
4009   return next_due;
4010 }
4011 #endif /* COAP_ASYNC_SUPPORT */
4012 #endif /* COAP_SERVER_SUPPORT */
4013 
4014 int coap_started = 0;
4015 
4016 #if COAP_CONSTRAINED_STACK
4017 coap_mutex_t m_show_pdu;
4018 coap_mutex_t m_log_impl;
4019 coap_mutex_t m_dtls_recv;
4020 coap_mutex_t m_read_session;
4021 coap_mutex_t m_read_endpoint;
4022 coap_mutex_t m_persist_add;
4023 #endif /* COAP_CONSTRAINED_STACK */
4024 
4025 void
4026 coap_startup(void) {
4027   coap_tick_t now;
4028 #ifndef WITH_CONTIKI
4029   uint64_t us;
4030 #endif /* !WITH_CONTIKI */
4031 
4032   if (coap_started)
4033     return;
4034   coap_started = 1;
4035 
4036 #if COAP_CONSTRAINED_STACK
4037   coap_mutex_init(&m_show_pdu);
4038   coap_mutex_init(&m_log_impl);
4039   coap_mutex_init(&m_dtls_recv);
4040   coap_mutex_init(&m_read_session);
4041   coap_mutex_init(&m_read_endpoint);
4042   coap_mutex_init(&m_persist_add);
4043 #endif /* COAP_CONSTRAINED_STACK */
4044 
4045 #if defined(HAVE_WINSOCK2_H)
4046   WORD wVersionRequested = MAKEWORD(2, 2);
4047   WSADATA wsaData;
4048   WSAStartup(wVersionRequested, &wsaData);
4049 #endif
4050   coap_clock_init();
4051   coap_ticks(&now);
4052 #ifndef WITH_CONTIKI
4053   us = coap_ticks_to_rt_us(now);
4054   /* Be accurate to the nearest (approx) us */
4055   coap_prng_init((unsigned int)us);
4056 #else /* WITH_CONTIKI */
4057   coap_start_io_process();
4058 #endif /* WITH_CONTIKI */
4059   coap_memory_init();
4060   coap_dtls_startup();
4061 #if COAP_SERVER_SUPPORT
4062   static coap_str_const_t well_known = { sizeof(".well-known/core")-1,
4063                                          (const uint8_t *)".well-known/core"
4064                                        };
4065   memset(&resource_uri_wellknown, 0, sizeof(resource_uri_wellknown));
4066   resource_uri_wellknown.handler[COAP_REQUEST_GET-1] = hnd_get_wellknown;
4067   resource_uri_wellknown.flags = COAP_RESOURCE_FLAGS_HAS_MCAST_SUPPORT;
4068   resource_uri_wellknown.uri_path = &well_known;
4069 #endif /* COAP_SERVER_SUPPORT */
4070 }
4071 
4072 void
4073 coap_cleanup(void) {
4074 #if defined(HAVE_WINSOCK2_H)
4075   WSACleanup();
4076 #elif defined(WITH_CONTIKI)
4077   coap_stop_io_process();
4078 #endif
4079   coap_dtls_shutdown();
4080 
4081 #if COAP_CONSTRAINED_STACK
4082   coap_mutex_destroy(&m_show_pdu);
4083   coap_mutex_destroy(&m_log_impl);
4084   coap_mutex_destroy(&m_dtls_recv);
4085   coap_mutex_destroy(&m_read_session);
4086   coap_mutex_destroy(&m_read_endpoint);
4087   coap_mutex_destroy(&m_persist_add);
4088 #endif /* COAP_CONSTRAINED_STACK */
4089   coap_debug_reset();
4090   coap_started = 0;
4091 }
4092 
4093 void
4094 coap_register_response_handler(coap_context_t *context,
4095                                coap_response_handler_t handler) {
4096 #if COAP_CLIENT_SUPPORT
4097   context->response_handler = handler;
4098 #else /* ! COAP_CLIENT_SUPPORT */
4099   (void)context;
4100   (void)handler;
4101 #endif /* COAP_CLIENT_SUPPORT */
4102 }
4103 
4104 void
4105 coap_register_nack_handler(coap_context_t *context,
4106                            coap_nack_handler_t handler) {
4107   context->nack_handler = handler;
4108 }
4109 
4110 void
4111 coap_register_ping_handler(coap_context_t *context,
4112                            coap_ping_handler_t handler) {
4113   context->ping_handler = handler;
4114 }
4115 
4116 void
4117 coap_register_pong_handler(coap_context_t *context,
4118                            coap_pong_handler_t handler) {
4119   context->pong_handler = handler;
4120 }
4121 
4122 void
4123 coap_register_option(coap_context_t *ctx, uint16_t type) {
4124   coap_option_filter_set(&ctx->known_options, type);
4125 }
4126 
4127 #if ! defined WITH_CONTIKI && ! defined WITH_LWIP && ! defined RIOT_VERSION
4128 #if COAP_SERVER_SUPPORT
4129 int
4130 coap_join_mcast_group_intf(coap_context_t *ctx, const char *group_name,
4131                            const char *ifname) {
4132 #if COAP_IPV4_SUPPORT
4133   struct ip_mreq mreq4;
4134 #endif /* COAP_IPV4_SUPPORT */
4135 #if COAP_IPV6_SUPPORT
4136   struct ipv6_mreq mreq6;
4137 #endif /* COAP_IPV6_SUPPORT */
4138   struct addrinfo *resmulti = NULL, hints, *ainfo;
4139   int result = -1;
4140   coap_endpoint_t *endpoint;
4141   int mgroup_setup = 0;
4142 
4143   /* Need to have at least one endpoint! */
4144   assert(ctx->endpoint);
4145   if (!ctx->endpoint)
4146     return -1;
4147 
4148   /* Default is let the kernel choose */
4149 #if COAP_IPV6_SUPPORT
4150   mreq6.ipv6mr_interface = 0;
4151 #endif /* COAP_IPV6_SUPPORT */
4152 #if COAP_IPV4_SUPPORT
4153   mreq4.imr_interface.s_addr = INADDR_ANY;
4154 #endif /* COAP_IPV4_SUPPORT */
4155 
4156   memset(&hints, 0, sizeof(hints));
4157   hints.ai_socktype = SOCK_DGRAM;
4158 
4159   /* resolve the multicast group address */
4160   result = getaddrinfo(group_name, NULL, &hints, &resmulti);
4161 
4162   if (result != 0) {
4163     coap_log_err("coap_join_mcast_group_intf: %s: "
4164                  "Cannot resolve multicast address: %s\n",
4165                  group_name, gai_strerror(result));
4166     goto finish;
4167   }
4168 
4169   /* Need to do a windows equivalent at some point */
4170 #ifndef _WIN32
4171   if (ifname) {
4172     /* interface specified - check if we have correct IPv4/IPv6 information */
4173     int done_ip4 = 0;
4174     int done_ip6 = 0;
4175 #if defined(ESPIDF_VERSION)
4176     struct netif *netif;
4177 #else /* !ESPIDF_VERSION */
4178 #if COAP_IPV4_SUPPORT
4179     int ip4fd;
4180 #endif /* COAP_IPV4_SUPPORT */
4181     struct ifreq ifr;
4182 #endif /* !ESPIDF_VERSION */
4183 
4184     /* See which mcast address family types are being asked for */
4185     for (ainfo = resmulti; ainfo != NULL && !(done_ip4 == 1 && done_ip6 == 1);
4186          ainfo = ainfo->ai_next) {
4187       switch (ainfo->ai_family) {
4188 #if COAP_IPV6_SUPPORT
4189       case AF_INET6:
4190         if (done_ip6)
4191           break;
4192         done_ip6 = 1;
4193 #if defined(ESPIDF_VERSION)
4194         netif = netif_find(ifname);
4195         if (netif)
4196           mreq6.ipv6mr_interface = netif_get_index(netif);
4197         else
4198           coap_log_err("coap_join_mcast_group_intf: %s: "
4199                        "Cannot get IPv4 address: %s\n",
4200                        ifname, coap_socket_strerror());
4201 #else /* !ESPIDF_VERSION */
4202         memset(&ifr, 0, sizeof(ifr));
4203         strncpy(ifr.ifr_name, ifname, IFNAMSIZ - 1);
4204         ifr.ifr_name[IFNAMSIZ - 1] = '\000';
4205 
4206 #ifdef HAVE_IF_NAMETOINDEX
4207         mreq6.ipv6mr_interface = if_nametoindex(ifr.ifr_name);
4208         if (mreq6.ipv6mr_interface == 0) {
4209           coap_log_warn("coap_join_mcast_group_intf: "
4210                         "cannot get interface index for '%s'\n",
4211                         ifname);
4212         }
4213 #else /* !HAVE_IF_NAMETOINDEX */
4214         result = ioctl(ctx->endpoint->sock.fd, SIOCGIFINDEX, &ifr);
4215         if (result != 0) {
4216           coap_log_warn("coap_join_mcast_group_intf: "
4217                         "cannot get interface index for '%s': %s\n",
4218                         ifname, coap_socket_strerror());
4219         } else {
4220           /* Capture the IPv6 if_index for later */
4221           mreq6.ipv6mr_interface = ifr.ifr_ifindex;
4222         }
4223 #endif /* !HAVE_IF_NAMETOINDEX */
4224 #endif /* !ESPIDF_VERSION */
4225 #endif /* COAP_IPV6_SUPPORT */
4226         break;
4227 #if COAP_IPV4_SUPPORT
4228       case AF_INET:
4229         if (done_ip4)
4230           break;
4231         done_ip4 = 1;
4232 #if defined(ESPIDF_VERSION)
4233         netif = netif_find(ifname);
4234         if (netif)
4235           mreq4.imr_interface.s_addr = netif_ip4_addr(netif)->addr;
4236         else
4237           coap_log_err("coap_join_mcast_group_intf: %s: "
4238                        "Cannot get IPv4 address: %s\n",
4239                        ifname, coap_socket_strerror());
4240 #else /* !ESPIDF_VERSION */
4241         /*
4242          * Need an AF_INET socket to do this unfortunately to stop
4243          * "Invalid argument" error if AF_INET6 socket is used for SIOCGIFADDR
4244          */
4245         ip4fd = socket(AF_INET, SOCK_DGRAM, 0);
4246         if (ip4fd == -1) {
4247           coap_log_err("coap_join_mcast_group_intf: %s: socket: %s\n",
4248                        ifname, coap_socket_strerror());
4249           continue;
4250         }
4251         memset(&ifr, 0, sizeof(ifr));
4252         strncpy(ifr.ifr_name, ifname, IFNAMSIZ - 1);
4253         ifr.ifr_name[IFNAMSIZ - 1] = '\000';
4254         result = ioctl(ip4fd, SIOCGIFADDR, &ifr);
4255         if (result != 0) {
4256           coap_log_err("coap_join_mcast_group_intf: %s: "
4257                        "Cannot get IPv4 address: %s\n",
4258                        ifname, coap_socket_strerror());
4259         } else {
4260           /* Capture the IPv4 address for later */
4261           mreq4.imr_interface = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
4262         }
4263         close(ip4fd);
4264 #endif /* !ESPIDF_VERSION */
4265         break;
4266 #endif /* COAP_IPV4_SUPPORT */
4267       default:
4268         break;
4269       }
4270     }
4271   }
4272 #endif /* ! _WIN32 */
4273 
4274   /* Add in mcast address(es) to appropriate interface */
4275   for (ainfo = resmulti; ainfo != NULL; ainfo = ainfo->ai_next) {
4276     LL_FOREACH(ctx->endpoint, endpoint) {
4277       /* Only UDP currently supported */
4278       if (endpoint->proto == COAP_PROTO_UDP) {
4279         coap_address_t gaddr;
4280 
4281         coap_address_init(&gaddr);
4282 #if COAP_IPV6_SUPPORT
4283         if (ainfo->ai_family == AF_INET6) {
4284           if (!ifname) {
4285             if (endpoint->bind_addr.addr.sa.sa_family == AF_INET6) {
4286               /*
4287                * Do it on the ifindex that the server is listening on
4288                * (sin6_scope_id could still be 0)
4289                */
4290               mreq6.ipv6mr_interface =
4291                   endpoint->bind_addr.addr.sin6.sin6_scope_id;
4292             } else {
4293               mreq6.ipv6mr_interface = 0;
4294             }
4295           }
4296           gaddr.addr.sin6.sin6_family = AF_INET6;
4297           gaddr.addr.sin6.sin6_port = endpoint->bind_addr.addr.sin6.sin6_port;
4298           gaddr.addr.sin6.sin6_addr = mreq6.ipv6mr_multiaddr =
4299                                           ((struct sockaddr_in6 *)ainfo->ai_addr)->sin6_addr;
4300           result = setsockopt(endpoint->sock.fd, IPPROTO_IPV6, IPV6_JOIN_GROUP,
4301                               (char *)&mreq6, sizeof(mreq6));
4302         }
4303 #endif /* COAP_IPV6_SUPPORT */
4304 #if COAP_IPV4_SUPPORT && COAP_IPV6_SUPPORT
4305         else
4306 #endif /* COAP_IPV4_SUPPORT && COAP_IPV6_SUPPORT */
4307 #if COAP_IPV4_SUPPORT
4308           if (ainfo->ai_family == AF_INET) {
4309             if (!ifname) {
4310               if (endpoint->bind_addr.addr.sa.sa_family == AF_INET) {
4311                 /*
4312                  * Do it on the interface that the server is listening on
4313                  * (sin_addr could still be INADDR_ANY)
4314                  */
4315                 mreq4.imr_interface = endpoint->bind_addr.addr.sin.sin_addr;
4316               } else {
4317                 mreq4.imr_interface.s_addr = INADDR_ANY;
4318               }
4319             }
4320             gaddr.addr.sin.sin_family = AF_INET;
4321             gaddr.addr.sin.sin_port = endpoint->bind_addr.addr.sin.sin_port;
4322             gaddr.addr.sin.sin_addr.s_addr = mreq4.imr_multiaddr.s_addr =
4323                                                  ((struct sockaddr_in *)ainfo->ai_addr)->sin_addr.s_addr;
4324             result = setsockopt(endpoint->sock.fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
4325                                 (char *)&mreq4, sizeof(mreq4));
4326           }
4327 #endif /* COAP_IPV4_SUPPORT */
4328           else {
4329             continue;
4330           }
4331 
4332         if (result == COAP_SOCKET_ERROR) {
4333           coap_log_err("coap_join_mcast_group_intf: %s: setsockopt: %s\n",
4334                        group_name, coap_socket_strerror());
4335         } else {
4336           char addr_str[INET6_ADDRSTRLEN + 8 + 1];
4337 
4338           addr_str[sizeof(addr_str)-1] = '\000';
4339           if (coap_print_addr(&gaddr, (uint8_t *)addr_str,
4340                               sizeof(addr_str) - 1)) {
4341             if (ifname)
4342               coap_log_debug("added mcast group %s i/f %s\n", addr_str,
4343                              ifname);
4344             else
4345               coap_log_debug("added mcast group %s\n", addr_str);
4346           }
4347           mgroup_setup = 1;
4348         }
4349       }
4350     }
4351   }
4352   if (!mgroup_setup) {
4353     result = -1;
4354   }
4355 
4356 finish:
4357   freeaddrinfo(resmulti);
4358 
4359   return result;
4360 }
4361 
4362 void
4363 coap_mcast_per_resource(coap_context_t *context) {
4364   context->mcast_per_resource = 1;
4365 }
4366 
4367 #endif /* ! COAP_SERVER_SUPPORT */
4368 
4369 #if COAP_CLIENT_SUPPORT
4370 int
4371 coap_mcast_set_hops(coap_session_t *session, size_t hops) {
4372   if (session && coap_is_mcast(&session->addr_info.remote)) {
4373     switch (session->addr_info.remote.addr.sa.sa_family) {
4374 #if COAP_IPV4_SUPPORT
4375     case AF_INET:
4376       if (setsockopt(session->sock.fd, IPPROTO_IP, IP_MULTICAST_TTL,
4377                      (const char *)&hops, sizeof(hops)) < 0) {
4378         coap_log_info("coap_mcast_set_hops: %zu: setsockopt: %s\n",
4379                       hops, coap_socket_strerror());
4380         return 0;
4381       }
4382       return 1;
4383 #endif /* COAP_IPV4_SUPPORT */
4384 #if COAP_IPV6_SUPPORT
4385     case AF_INET6:
4386       if (setsockopt(session->sock.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
4387                      (const char *)&hops, sizeof(hops)) < 0) {
4388         coap_log_info("coap_mcast_set_hops: %zu: setsockopt: %s\n",
4389                       hops, coap_socket_strerror());
4390         return 0;
4391       }
4392       return 1;
4393 #endif /* COAP_IPV6_SUPPORT */
4394     default:
4395       break;
4396     }
4397   }
4398   return 0;
4399 }
4400 #endif /* COAP_CLIENT_SUPPORT */
4401 
4402 #else /* defined WITH_CONTIKI || defined WITH_LWIP */
4403 int
4404 coap_join_mcast_group_intf(coap_context_t *ctx COAP_UNUSED,
4405                            const char *group_name COAP_UNUSED,
4406                            const char *ifname COAP_UNUSED) {
4407   return -1;
4408 }
4409 
4410 int
4411 coap_mcast_set_hops(coap_session_t *session COAP_UNUSED,
4412                     size_t hops COAP_UNUSED) {
4413   return 0;
4414 }
4415 
4416 void
4417 coap_mcast_per_resource(coap_context_t *context COAP_UNUSED) {
4418 }
4419 #endif /* defined WITH_CONTIKI || defined WITH_LWIP */
4420