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1 /**
2  * @file
3  * TCP internal implementations (do not use in application code)
4  */
5 
6 /*
7  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without modification,
11  * are permitted provided that the following conditions are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright notice,
14  *    this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright notice,
16  *    this list of conditions and the following disclaimer in the documentation
17  *    and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30  * OF SUCH DAMAGE.
31  *
32  * This file is part of the lwIP TCP/IP stack.
33  *
34  * Author: Adam Dunkels <adam@sics.se>
35  *
36  */
37 #ifndef LWIP_HDR_TCP_PRIV_H
38 #define LWIP_HDR_TCP_PRIV_H
39 
40 #include "lwip/opt.h"
41 
42 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
43 
44 #include "lwip/tcp.h"
45 #include "lwip/mem.h"
46 #include "lwip/pbuf.h"
47 #include "lwip/ip.h"
48 #include "lwip/icmp.h"
49 #include "lwip/err.h"
50 #include "lwip/ip6.h"
51 #include "lwip/ip6_addr.h"
52 #include "lwip/prot/tcp.h"
53 
54 #ifdef __cplusplus
55 extern "C" {
56 #endif
57 
58 /* Functions for interfacing with TCP: */
59 
60 /* Lower layer interface to TCP: */
61 void             tcp_init    (void);  /* Initialize this module. */
62 void             tcp_tmr     (void);  /* Must be called every
63                                          TCP_TMR_INTERVAL
64                                          ms. (Typically 250 ms). */
65 /* It is also possible to call these two functions at the right
66    intervals (instead of calling tcp_tmr()). */
67 void             tcp_slowtmr (void);
68 void             tcp_fasttmr (void);
69 
70 /* Call this from a netif driver (watch out for threading issues!) that has
71    returned a memory error on transmit and now has free buffers to send more.
72    This iterates all active pcbs that had an error and tries to call
73    tcp_output, so use this with care as it might slow down the system. */
74 void             tcp_txnow   (void);
75 
76 /* Only used by IP to pass a TCP segment to TCP: */
77 void             tcp_input   (struct pbuf *p, struct netif *inp);
78 /* Used within the TCP code only: */
79 struct tcp_pcb * tcp_alloc   (u8_t prio);
80 void             tcp_free    (struct tcp_pcb *pcb);
81 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
82 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
83 err_t            tcp_rexmit  (struct tcp_pcb *pcb);
84 err_t            tcp_rexmit_rto_prepare(struct tcp_pcb *pcb);
85 void             tcp_rexmit_rto_commit(struct tcp_pcb *pcb);
86 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
87 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
88 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
89 err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
90 
91 /**
92  * This is the Nagle algorithm: try to combine user data to send as few TCP
93  * segments as possible. Only send if
94  * - no previously transmitted data on the connection remains unacknowledged or
95  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
96  * - the only unsent segment is at least pcb->mss bytes long (or there is more
97  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
98  * - or if we are in fast-retransmit (TF_INFR)
99  */
100 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
101                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
102                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
103                               ((tpcb)->unsent->len >= (tpcb)->mss))) || \
104                             ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
105                             ) ? 1 : 0)
106 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
107 
108 
109 #define TCP_SEQ_LT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
110 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
111 #define TCP_SEQ_GT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
112 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
113 /* is b<=a<=c? */
114 #if 0 /* see bug #10548 */
115 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
116 #endif
117 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
118 
119 #ifndef TCP_TMR_INTERVAL
120 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
121 #endif /* TCP_TMR_INTERVAL */
122 
123 #ifndef TCP_FAST_INTERVAL
124 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
125 #endif /* TCP_FAST_INTERVAL */
126 
127 #ifndef TCP_SLOW_INTERVAL
128 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
129 #endif /* TCP_SLOW_INTERVAL */
130 
131 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
132 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
133 
134 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
135 
136 #ifndef TCP_MSL
137 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
138 #endif
139 
140 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
141 #ifndef  TCP_KEEPIDLE_DEFAULT
142 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
143 #endif
144 
145 #ifndef  TCP_KEEPINTVL_DEFAULT
146 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
147 #endif
148 
149 #ifndef  TCP_KEEPCNT_DEFAULT
150 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
151 #endif
152 
153 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
154 
155 #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))
156 
157 /** Flags used on input processing, not on pcb->flags
158 */
159 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
160 #define TF_CLOSED    (u8_t)0x10U   /* Connection was successfully closed. */
161 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
162 
163 
164 #if LWIP_EVENT_API
165 
166 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(arg, (pcb),\
167                 LWIP_EVENT_ACCEPT, NULL, 0, err)
168 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
169                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
170 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
171                 LWIP_EVENT_RECV, (p), 0, (err))
172 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
173                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
174 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
175                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
176 #define TCP_EVENT_POLL(pcb,ret)       do { if ((pcb)->state != SYN_RCVD) {                          \
177                 ret = lwip_tcp_event((pcb)->callback_arg, (pcb), LWIP_EVENT_POLL, NULL, 0, ERR_OK); \
178                 } else {                                                                            \
179                 ret = ERR_ARG; } } while(0)
180 /* For event API, last state SYN_RCVD must be excluded here: the application
181    has not seen this pcb, yet! */
182 #define TCP_EVENT_ERR(last_state,errf,arg,err)  do { if (last_state != SYN_RCVD) {                \
183                 lwip_tcp_event((arg), NULL, LWIP_EVENT_ERR, NULL, 0, (err)); } } while(0)
184 
185 #else /* LWIP_EVENT_API */
186 
187 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret)                 \
188   do {                                                         \
189     if((lpcb)->accept != NULL)                                 \
190       (ret) = (lpcb)->accept((arg),(pcb),(err));               \
191     else (ret) = ERR_ARG;                                      \
192   } while (0)
193 
194 #define TCP_EVENT_SENT(pcb,space,ret)                          \
195   do {                                                         \
196     if((pcb)->sent != NULL)                                    \
197       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
198     else (ret) = ERR_OK;                                       \
199   } while (0)
200 
201 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
202   do {                                                         \
203     if((pcb)->recv != NULL) {                                  \
204       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
205     } else {                                                   \
206       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
207     }                                                          \
208   } while (0)
209 
210 #define TCP_EVENT_CLOSED(pcb,ret)                                \
211   do {                                                           \
212     if(((pcb)->recv != NULL)) {                                  \
213       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
214     } else {                                                     \
215       (ret) = ERR_OK;                                            \
216     }                                                            \
217   } while (0)
218 
219 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
220   do {                                                           \
221     if((pcb)->connected != NULL)                                 \
222       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
223     else (ret) = ERR_OK;                                         \
224   } while (0)
225 
226 #define TCP_EVENT_POLL(pcb,ret)                                \
227   do {                                                         \
228     if((pcb)->poll != NULL)                                    \
229       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
230     else (ret) = ERR_OK;                                       \
231   } while (0)
232 
233 #define TCP_EVENT_ERR(last_state,errf,arg,err)                 \
234   do {                                                         \
235     LWIP_UNUSED_ARG(last_state);                               \
236     if((errf) != NULL)                                         \
237       (errf)((arg),(err));                                     \
238   } while (0)
239 
240 #endif /* LWIP_EVENT_API */
241 
242 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
243 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
244 #define TCP_OVERSIZE_DBGCHECK 1
245 #else
246 #define TCP_OVERSIZE_DBGCHECK 0
247 #endif
248 
249 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
250 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
251 
252 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
253 struct tcp_seg {
254   struct tcp_seg *next;    /* used when putting segments on a queue */
255   struct pbuf *p;          /* buffer containing data + TCP header */
256   u16_t len;               /* the TCP length of this segment */
257 #if TCP_OVERSIZE_DBGCHECK
258   u16_t oversize_left;     /* Extra bytes available at the end of the last
259                               pbuf in unsent (used for asserting vs.
260                               tcp_pcb.unsent_oversize only) */
261 #endif /* TCP_OVERSIZE_DBGCHECK */
262 #if TCP_CHECKSUM_ON_COPY
263   u16_t chksum;
264   u8_t  chksum_swapped;
265 #endif /* TCP_CHECKSUM_ON_COPY */
266   u8_t  flags;
267 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option (only used in SYN segments) */
268 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
269 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
270                                                checksummed into 'chksum' */
271 #define TF_SEG_OPTS_WND_SCALE   (u8_t)0x08U /* Include WND SCALE option (only used in SYN segments) */
272 #define TF_SEG_OPTS_SACK_PERM   (u8_t)0x10U /* Include SACK Permitted option (only used in SYN segments) */
273   struct tcp_hdr *tcphdr;  /* the TCP header */
274 };
275 
276 #define LWIP_TCP_OPT_EOL        0
277 #define LWIP_TCP_OPT_NOP        1
278 #define LWIP_TCP_OPT_MSS        2
279 #define LWIP_TCP_OPT_WS         3
280 #define LWIP_TCP_OPT_SACK_PERM  4
281 #define LWIP_TCP_OPT_TS         8
282 
283 #define LWIP_TCP_OPT_LEN_MSS    4
284 #if LWIP_TCP_TIMESTAMPS
285 #define LWIP_TCP_OPT_LEN_TS     10
286 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */
287 #else
288 #define LWIP_TCP_OPT_LEN_TS_OUT 0
289 #endif
290 #if LWIP_WND_SCALE
291 #define LWIP_TCP_OPT_LEN_WS     3
292 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */
293 #else
294 #define LWIP_TCP_OPT_LEN_WS_OUT 0
295 #endif
296 
297 #if LWIP_TCP_SACK_OUT
298 #define LWIP_TCP_OPT_LEN_SACK_PERM     2
299 #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 4 /* aligned for output (includes NOP padding) */
300 #else
301 #define LWIP_TCP_OPT_LEN_SACK_PERM_OUT 0
302 #endif
303 
304 #define LWIP_TCP_OPT_LENGTH(flags) \
305   ((flags) & TF_SEG_OPTS_MSS       ? LWIP_TCP_OPT_LEN_MSS           : 0) + \
306   ((flags) & TF_SEG_OPTS_TS        ? LWIP_TCP_OPT_LEN_TS_OUT        : 0) + \
307   ((flags) & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT        : 0) + \
308   ((flags) & TF_SEG_OPTS_SACK_PERM ? LWIP_TCP_OPT_LEN_SACK_PERM_OUT : 0)
309 
310 /** This returns a TCP header option for MSS in an u32_t */
311 #define TCP_BUILD_MSS_OPTION(mss) lwip_htonl(0x02040000 | ((mss) & 0xFFFF))
312 
313 #if LWIP_WND_SCALE
314 #define TCPWNDSIZE_F       U32_F
315 #define TCPWND_MAX         0xFFFFFFFFU
316 #define TCPWND_CHECK16(x)  LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF)
317 #define TCPWND_MIN16(x)    ((u16_t)LWIP_MIN((x), 0xFFFF))
318 #else /* LWIP_WND_SCALE */
319 #define TCPWNDSIZE_F       U16_F
320 #define TCPWND_MAX         0xFFFFU
321 #define TCPWND_CHECK16(x)
322 #define TCPWND_MIN16(x)    x
323 #endif /* LWIP_WND_SCALE */
324 
325 /* Global variables: */
326 extern struct tcp_pcb *tcp_input_pcb;
327 extern u32_t tcp_ticks;
328 extern u8_t tcp_active_pcbs_changed;
329 
330 /* The TCP PCB lists. */
331 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
332   struct tcp_pcb_listen *listen_pcbs;
333   struct tcp_pcb *pcbs;
334 };
335 extern struct tcp_pcb *tcp_bound_pcbs;
336 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
337 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
338               state in which they accept or send
339               data. */
340 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
341 
342 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
343 #define NUM_TCP_PCB_LISTS               4
344 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
345 
346 /* Axioms about the above lists:
347    1) Every TCP PCB that is not CLOSED is in one of the lists.
348    2) A PCB is only in one of the lists.
349    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
350    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
351 */
352 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
353    with a PCB list or removes a PCB from a list, respectively. */
354 #ifndef TCP_DEBUG_PCB_LISTS
355 #define TCP_DEBUG_PCB_LISTS 0
356 #endif
357 #if TCP_DEBUG_PCB_LISTS
358 #define TCP_REG(pcbs, npcb) do {\
359                             struct tcp_pcb *tcp_tmp_pcb; \
360                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %"U16_F"\n", (void *)(npcb), (npcb)->local_port)); \
361                             for (tcp_tmp_pcb = *(pcbs); \
362           tcp_tmp_pcb != NULL; \
363         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
364                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
365                             } \
366                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
367                             (npcb)->next = *(pcbs); \
368                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
369                             *(pcbs) = (npcb); \
370                             LWIP_ASSERT("TCP_REG: tcp_pcbs sane", tcp_pcbs_sane()); \
371               tcp_timer_needed(); \
372                             } while(0)
373 #define TCP_RMV(pcbs, npcb) do { \
374                             struct tcp_pcb *tcp_tmp_pcb; \
375                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
376                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (void *)(npcb), (void *)(*(pcbs)))); \
377                             if(*(pcbs) == (npcb)) { \
378                                *(pcbs) = (*pcbs)->next; \
379                             } else for (tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
380                                if(tcp_tmp_pcb->next == (npcb)) { \
381                                   tcp_tmp_pcb->next = (npcb)->next; \
382                                   break; \
383                                } \
384                             } \
385                             (npcb)->next = NULL; \
386                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
387                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (void *)(npcb), (void *)(*(pcbs)))); \
388                             } while(0)
389 
390 #else /* LWIP_DEBUG */
391 
392 #define TCP_REG(pcbs, npcb)                        \
393   do {                                             \
394     (npcb)->next = *pcbs;                          \
395     *(pcbs) = (npcb);                              \
396     tcp_timer_needed();                            \
397   } while (0)
398 
399 #define TCP_RMV(pcbs, npcb)                        \
400   do {                                             \
401     if(*(pcbs) == (npcb)) {                        \
402       (*(pcbs)) = (*pcbs)->next;                   \
403     }                                              \
404     else {                                         \
405       struct tcp_pcb *tcp_tmp_pcb;                 \
406       for (tcp_tmp_pcb = *pcbs;                    \
407           tcp_tmp_pcb != NULL;                     \
408           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
409         if(tcp_tmp_pcb->next == (npcb)) {          \
410           tcp_tmp_pcb->next = (npcb)->next;        \
411           break;                                   \
412         }                                          \
413       }                                            \
414     }                                              \
415     (npcb)->next = NULL;                           \
416   } while(0)
417 
418 #endif /* LWIP_DEBUG */
419 
420 #define TCP_REG_ACTIVE(npcb)                       \
421   do {                                             \
422     TCP_REG(&tcp_active_pcbs, npcb);               \
423     tcp_active_pcbs_changed = 1;                   \
424   } while (0)
425 
426 #define TCP_RMV_ACTIVE(npcb)                       \
427   do {                                             \
428     TCP_RMV(&tcp_active_pcbs, npcb);               \
429     tcp_active_pcbs_changed = 1;                   \
430   } while (0)
431 
432 #define TCP_PCB_REMOVE_ACTIVE(pcb)                 \
433   do {                                             \
434     tcp_pcb_remove(&tcp_active_pcbs, pcb);         \
435     tcp_active_pcbs_changed = 1;                   \
436   } while (0)
437 
438 
439 /* Internal functions: */
440 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
441 void tcp_pcb_purge(struct tcp_pcb *pcb);
442 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
443 
444 void tcp_segs_free(struct tcp_seg *seg);
445 void tcp_seg_free(struct tcp_seg *seg);
446 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
447 
448 #define tcp_ack(pcb)                               \
449   do {                                             \
450     if((pcb)->flags & TF_ACK_DELAY) {              \
451       tcp_clear_flags(pcb, TF_ACK_DELAY);          \
452       tcp_ack_now(pcb);                            \
453     }                                              \
454     else {                                         \
455       tcp_set_flags(pcb, TF_ACK_DELAY);            \
456     }                                              \
457   } while (0)
458 
459 #define tcp_ack_now(pcb)                           \
460   tcp_set_flags(pcb, TF_ACK_NOW)
461 
462 err_t tcp_send_fin(struct tcp_pcb *pcb);
463 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
464 
465 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
466 
467 void tcp_rst(const struct tcp_pcb* pcb, u32_t seqno, u32_t ackno,
468        const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
469        u16_t local_port, u16_t remote_port);
470 
471 u32_t tcp_next_iss(struct tcp_pcb *pcb);
472 
473 err_t tcp_keepalive(struct tcp_pcb *pcb);
474 err_t tcp_split_unsent_seg(struct tcp_pcb *pcb, u16_t split);
475 err_t tcp_zero_window_probe(struct tcp_pcb *pcb);
476 void  tcp_trigger_input_pcb_close(void);
477 
478 #if TCP_CALCULATE_EFF_SEND_MSS
479 u16_t tcp_eff_send_mss_netif(u16_t sendmss, struct netif *outif,
480                              const ip_addr_t *dest);
481 #ifdef LOSCFG_NET_CONTAINER
482 #define tcp_eff_send_mss(sendmss, src, dest, group) \
483     tcp_eff_send_mss_netif(sendmss, ip_route(src, dest, group), dest)
484 #else
485 #define tcp_eff_send_mss(sendmss, src, dest) \
486     tcp_eff_send_mss_netif(sendmss, ip_route(src, dest), dest)
487 #endif
488 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
489 
490 #if LWIP_CALLBACK_API
491 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
492 #endif /* LWIP_CALLBACK_API */
493 
494 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
495 void tcp_debug_print(struct tcp_hdr *tcphdr);
496 void tcp_debug_print_flags(u8_t flags);
497 void tcp_debug_print_state(enum tcp_state s);
498 void tcp_debug_print_pcbs(void);
499 s16_t tcp_pcbs_sane(void);
500 #else
501 #  define tcp_debug_print(tcphdr)
502 #  define tcp_debug_print_flags(flags)
503 #  define tcp_debug_print_state(s)
504 #  define tcp_debug_print_pcbs()
505 #  define tcp_pcbs_sane() 1
506 #endif /* TCP_DEBUG */
507 
508 /** External function (implemented in timers.c), called when TCP detects
509  * that a timer is needed (i.e. active- or time-wait-pcb found). */
510 void tcp_timer_needed(void);
511 
512 void tcp_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr);
513 
514 #if TCP_QUEUE_OOSEQ
515 void tcp_free_ooseq(struct tcp_pcb *pcb);
516 #endif
517 
518 #if LWIP_TCP_PCB_NUM_EXT_ARGS
519 err_t tcp_ext_arg_invoke_callbacks_passive_open(struct tcp_pcb_listen *lpcb, struct tcp_pcb *cpcb);
520 #endif
521 
522 #ifdef __cplusplus
523 }
524 #endif
525 
526 #endif /* LWIP_TCP */
527 
528 #endif /* LWIP_HDR_TCP_PRIV_H */
529