1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * net/dccp/proto.c
4 *
5 * An implementation of the DCCP protocol
6 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 */
8
9 #include <linux/dccp.h>
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/skbuff.h>
15 #include <linux/netdevice.h>
16 #include <linux/in.h>
17 #include <linux/if_arp.h>
18 #include <linux/init.h>
19 #include <linux/random.h>
20 #include <linux/slab.h>
21 #include <net/checksum.h>
22
23 #include <net/inet_sock.h>
24 #include <net/inet_common.h>
25 #include <net/sock.h>
26 #include <net/xfrm.h>
27
28 #include <asm/ioctls.h>
29 #include <linux/spinlock.h>
30 #include <linux/timer.h>
31 #include <linux/delay.h>
32 #include <linux/poll.h>
33
34 #include "ccid.h"
35 #include "dccp.h"
36 #include "feat.h"
37
38 #define CREATE_TRACE_POINTS
39 #include "trace.h"
40
41 DEFINE_SNMP_STAT(struct dccp_mib, dccp_statistics) __read_mostly;
42
43 EXPORT_SYMBOL_GPL(dccp_statistics);
44
45 struct percpu_counter dccp_orphan_count;
46 EXPORT_SYMBOL_GPL(dccp_orphan_count);
47
48 struct inet_hashinfo dccp_hashinfo;
49 EXPORT_SYMBOL_GPL(dccp_hashinfo);
50
51 /* the maximum queue length for tx in packets. 0 is no limit */
52 int sysctl_dccp_tx_qlen __read_mostly = 5;
53
54 #ifdef CONFIG_IP_DCCP_DEBUG
dccp_state_name(const int state)55 static const char *dccp_state_name(const int state)
56 {
57 static const char *const dccp_state_names[] = {
58 [DCCP_OPEN] = "OPEN",
59 [DCCP_REQUESTING] = "REQUESTING",
60 [DCCP_PARTOPEN] = "PARTOPEN",
61 [DCCP_LISTEN] = "LISTEN",
62 [DCCP_RESPOND] = "RESPOND",
63 [DCCP_CLOSING] = "CLOSING",
64 [DCCP_ACTIVE_CLOSEREQ] = "CLOSEREQ",
65 [DCCP_PASSIVE_CLOSE] = "PASSIVE_CLOSE",
66 [DCCP_PASSIVE_CLOSEREQ] = "PASSIVE_CLOSEREQ",
67 [DCCP_TIME_WAIT] = "TIME_WAIT",
68 [DCCP_CLOSED] = "CLOSED",
69 };
70
71 if (state >= DCCP_MAX_STATES)
72 return "INVALID STATE!";
73 else
74 return dccp_state_names[state];
75 }
76 #endif
77
dccp_set_state(struct sock * sk,const int state)78 void dccp_set_state(struct sock *sk, const int state)
79 {
80 const int oldstate = sk->sk_state;
81
82 dccp_pr_debug("%s(%p) %s --> %s\n", dccp_role(sk), sk,
83 dccp_state_name(oldstate), dccp_state_name(state));
84 WARN_ON(state == oldstate);
85
86 switch (state) {
87 case DCCP_OPEN:
88 if (oldstate != DCCP_OPEN)
89 DCCP_INC_STATS(DCCP_MIB_CURRESTAB);
90 /* Client retransmits all Confirm options until entering OPEN */
91 if (oldstate == DCCP_PARTOPEN)
92 dccp_feat_list_purge(&dccp_sk(sk)->dccps_featneg);
93 break;
94
95 case DCCP_CLOSED:
96 if (oldstate == DCCP_OPEN || oldstate == DCCP_ACTIVE_CLOSEREQ ||
97 oldstate == DCCP_CLOSING)
98 DCCP_INC_STATS(DCCP_MIB_ESTABRESETS);
99
100 sk->sk_prot->unhash(sk);
101 if (inet_csk(sk)->icsk_bind_hash != NULL &&
102 !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
103 inet_put_port(sk);
104 /* fall through */
105 default:
106 if (oldstate == DCCP_OPEN)
107 DCCP_DEC_STATS(DCCP_MIB_CURRESTAB);
108 }
109
110 /* Change state AFTER socket is unhashed to avoid closed
111 * socket sitting in hash tables.
112 */
113 inet_sk_set_state(sk, state);
114 }
115
116 EXPORT_SYMBOL_GPL(dccp_set_state);
117
dccp_finish_passive_close(struct sock * sk)118 static void dccp_finish_passive_close(struct sock *sk)
119 {
120 switch (sk->sk_state) {
121 case DCCP_PASSIVE_CLOSE:
122 /* Node (client or server) has received Close packet. */
123 dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
124 dccp_set_state(sk, DCCP_CLOSED);
125 break;
126 case DCCP_PASSIVE_CLOSEREQ:
127 /*
128 * Client received CloseReq. We set the `active' flag so that
129 * dccp_send_close() retransmits the Close as per RFC 4340, 8.3.
130 */
131 dccp_send_close(sk, 1);
132 dccp_set_state(sk, DCCP_CLOSING);
133 }
134 }
135
dccp_done(struct sock * sk)136 void dccp_done(struct sock *sk)
137 {
138 dccp_set_state(sk, DCCP_CLOSED);
139 dccp_clear_xmit_timers(sk);
140
141 sk->sk_shutdown = SHUTDOWN_MASK;
142
143 if (!sock_flag(sk, SOCK_DEAD))
144 sk->sk_state_change(sk);
145 else
146 inet_csk_destroy_sock(sk);
147 }
148
149 EXPORT_SYMBOL_GPL(dccp_done);
150
dccp_packet_name(const int type)151 const char *dccp_packet_name(const int type)
152 {
153 static const char *const dccp_packet_names[] = {
154 [DCCP_PKT_REQUEST] = "REQUEST",
155 [DCCP_PKT_RESPONSE] = "RESPONSE",
156 [DCCP_PKT_DATA] = "DATA",
157 [DCCP_PKT_ACK] = "ACK",
158 [DCCP_PKT_DATAACK] = "DATAACK",
159 [DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
160 [DCCP_PKT_CLOSE] = "CLOSE",
161 [DCCP_PKT_RESET] = "RESET",
162 [DCCP_PKT_SYNC] = "SYNC",
163 [DCCP_PKT_SYNCACK] = "SYNCACK",
164 };
165
166 if (type >= DCCP_NR_PKT_TYPES)
167 return "INVALID";
168 else
169 return dccp_packet_names[type];
170 }
171
172 EXPORT_SYMBOL_GPL(dccp_packet_name);
173
dccp_destruct_common(struct sock * sk)174 void dccp_destruct_common(struct sock *sk)
175 {
176 struct dccp_sock *dp = dccp_sk(sk);
177
178 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
179 dp->dccps_hc_tx_ccid = NULL;
180 }
181 EXPORT_SYMBOL_GPL(dccp_destruct_common);
182
dccp_sk_destruct(struct sock * sk)183 static void dccp_sk_destruct(struct sock *sk)
184 {
185 dccp_destruct_common(sk);
186 inet_sock_destruct(sk);
187 }
188
dccp_init_sock(struct sock * sk,const __u8 ctl_sock_initialized)189 int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
190 {
191 struct dccp_sock *dp = dccp_sk(sk);
192 struct inet_connection_sock *icsk = inet_csk(sk);
193
194 icsk->icsk_rto = DCCP_TIMEOUT_INIT;
195 icsk->icsk_syn_retries = sysctl_dccp_request_retries;
196 sk->sk_state = DCCP_CLOSED;
197 sk->sk_write_space = dccp_write_space;
198 sk->sk_destruct = dccp_sk_destruct;
199 icsk->icsk_sync_mss = dccp_sync_mss;
200 dp->dccps_mss_cache = 536;
201 dp->dccps_rate_last = jiffies;
202 dp->dccps_role = DCCP_ROLE_UNDEFINED;
203 dp->dccps_service = DCCP_SERVICE_CODE_IS_ABSENT;
204 dp->dccps_tx_qlen = sysctl_dccp_tx_qlen;
205
206 dccp_init_xmit_timers(sk);
207
208 INIT_LIST_HEAD(&dp->dccps_featneg);
209 /* control socket doesn't need feat nego */
210 if (likely(ctl_sock_initialized))
211 return dccp_feat_init(sk);
212 return 0;
213 }
214
215 EXPORT_SYMBOL_GPL(dccp_init_sock);
216
dccp_destroy_sock(struct sock * sk)217 void dccp_destroy_sock(struct sock *sk)
218 {
219 struct dccp_sock *dp = dccp_sk(sk);
220
221 __skb_queue_purge(&sk->sk_write_queue);
222 if (sk->sk_send_head != NULL) {
223 kfree_skb(sk->sk_send_head);
224 sk->sk_send_head = NULL;
225 }
226
227 /* Clean up a referenced DCCP bind bucket. */
228 if (inet_csk(sk)->icsk_bind_hash != NULL)
229 inet_put_port(sk);
230
231 kfree(dp->dccps_service_list);
232 dp->dccps_service_list = NULL;
233
234 if (dp->dccps_hc_rx_ackvec != NULL) {
235 dccp_ackvec_free(dp->dccps_hc_rx_ackvec);
236 dp->dccps_hc_rx_ackvec = NULL;
237 }
238 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
239 dp->dccps_hc_rx_ccid = NULL;
240
241 /* clean up feature negotiation state */
242 dccp_feat_list_purge(&dp->dccps_featneg);
243 }
244
245 EXPORT_SYMBOL_GPL(dccp_destroy_sock);
246
dccp_listen_start(struct sock * sk,int backlog)247 static inline int dccp_listen_start(struct sock *sk, int backlog)
248 {
249 struct dccp_sock *dp = dccp_sk(sk);
250
251 dp->dccps_role = DCCP_ROLE_LISTEN;
252 /* do not start to listen if feature negotiation setup fails */
253 if (dccp_feat_finalise_settings(dp))
254 return -EPROTO;
255 return inet_csk_listen_start(sk, backlog);
256 }
257
dccp_need_reset(int state)258 static inline int dccp_need_reset(int state)
259 {
260 return state != DCCP_CLOSED && state != DCCP_LISTEN &&
261 state != DCCP_REQUESTING;
262 }
263
dccp_disconnect(struct sock * sk,int flags)264 int dccp_disconnect(struct sock *sk, int flags)
265 {
266 struct inet_connection_sock *icsk = inet_csk(sk);
267 struct inet_sock *inet = inet_sk(sk);
268 struct dccp_sock *dp = dccp_sk(sk);
269 const int old_state = sk->sk_state;
270
271 if (old_state != DCCP_CLOSED)
272 dccp_set_state(sk, DCCP_CLOSED);
273
274 /*
275 * This corresponds to the ABORT function of RFC793, sec. 3.8
276 * TCP uses a RST segment, DCCP a Reset packet with Code 2, "Aborted".
277 */
278 if (old_state == DCCP_LISTEN) {
279 inet_csk_listen_stop(sk);
280 } else if (dccp_need_reset(old_state)) {
281 dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
282 sk->sk_err = ECONNRESET;
283 } else if (old_state == DCCP_REQUESTING)
284 sk->sk_err = ECONNRESET;
285
286 dccp_clear_xmit_timers(sk);
287 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
288 dp->dccps_hc_rx_ccid = NULL;
289
290 __skb_queue_purge(&sk->sk_receive_queue);
291 __skb_queue_purge(&sk->sk_write_queue);
292 if (sk->sk_send_head != NULL) {
293 __kfree_skb(sk->sk_send_head);
294 sk->sk_send_head = NULL;
295 }
296
297 inet->inet_dport = 0;
298
299 if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
300 inet_reset_saddr(sk);
301
302 sk->sk_shutdown = 0;
303 sock_reset_flag(sk, SOCK_DONE);
304
305 icsk->icsk_backoff = 0;
306 inet_csk_delack_init(sk);
307 __sk_dst_reset(sk);
308
309 WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
310
311 sk->sk_error_report(sk);
312 return 0;
313 }
314
315 EXPORT_SYMBOL_GPL(dccp_disconnect);
316
317 /*
318 * Wait for a DCCP event.
319 *
320 * Note that we don't need to lock the socket, as the upper poll layers
321 * take care of normal races (between the test and the event) and we don't
322 * go look at any of the socket buffers directly.
323 */
dccp_poll(struct file * file,struct socket * sock,poll_table * wait)324 __poll_t dccp_poll(struct file *file, struct socket *sock,
325 poll_table *wait)
326 {
327 struct sock *sk = sock->sk;
328 __poll_t mask;
329 u8 shutdown;
330 int state;
331
332 sock_poll_wait(file, sock, wait);
333
334 state = inet_sk_state_load(sk);
335 if (state == DCCP_LISTEN)
336 return inet_csk_listen_poll(sk);
337
338 /* Socket is not locked. We are protected from async events
339 by poll logic and correct handling of state changes
340 made by another threads is impossible in any case.
341 */
342
343 mask = 0;
344 if (READ_ONCE(sk->sk_err))
345 mask = EPOLLERR;
346 shutdown = READ_ONCE(sk->sk_shutdown);
347
348 if (shutdown == SHUTDOWN_MASK || state == DCCP_CLOSED)
349 mask |= EPOLLHUP;
350 if (shutdown & RCV_SHUTDOWN)
351 mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
352
353 /* Connected? */
354 if ((1 << state) & ~(DCCPF_REQUESTING | DCCPF_RESPOND)) {
355 if (atomic_read(&sk->sk_rmem_alloc) > 0)
356 mask |= EPOLLIN | EPOLLRDNORM;
357
358 if (!(shutdown & SEND_SHUTDOWN)) {
359 if (sk_stream_is_writeable(sk)) {
360 mask |= EPOLLOUT | EPOLLWRNORM;
361 } else { /* send SIGIO later */
362 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
363 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
364
365 /* Race breaker. If space is freed after
366 * wspace test but before the flags are set,
367 * IO signal will be lost.
368 */
369 if (sk_stream_is_writeable(sk))
370 mask |= EPOLLOUT | EPOLLWRNORM;
371 }
372 }
373 }
374 return mask;
375 }
376 EXPORT_SYMBOL_GPL(dccp_poll);
377
dccp_ioctl(struct sock * sk,int cmd,unsigned long arg)378 int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
379 {
380 int rc = -ENOTCONN;
381
382 lock_sock(sk);
383
384 if (sk->sk_state == DCCP_LISTEN)
385 goto out;
386
387 switch (cmd) {
388 case SIOCINQ: {
389 struct sk_buff *skb;
390 unsigned long amount = 0;
391
392 skb = skb_peek(&sk->sk_receive_queue);
393 if (skb != NULL) {
394 /*
395 * We will only return the amount of this packet since
396 * that is all that will be read.
397 */
398 amount = skb->len;
399 }
400 rc = put_user(amount, (int __user *)arg);
401 }
402 break;
403 default:
404 rc = -ENOIOCTLCMD;
405 break;
406 }
407 out:
408 release_sock(sk);
409 return rc;
410 }
411
412 EXPORT_SYMBOL_GPL(dccp_ioctl);
413
dccp_setsockopt_service(struct sock * sk,const __be32 service,char __user * optval,unsigned int optlen)414 static int dccp_setsockopt_service(struct sock *sk, const __be32 service,
415 char __user *optval, unsigned int optlen)
416 {
417 struct dccp_sock *dp = dccp_sk(sk);
418 struct dccp_service_list *sl = NULL;
419
420 if (service == DCCP_SERVICE_INVALID_VALUE ||
421 optlen > DCCP_SERVICE_LIST_MAX_LEN * sizeof(u32))
422 return -EINVAL;
423
424 if (optlen > sizeof(service)) {
425 sl = kmalloc(optlen, GFP_KERNEL);
426 if (sl == NULL)
427 return -ENOMEM;
428
429 sl->dccpsl_nr = optlen / sizeof(u32) - 1;
430 if (copy_from_user(sl->dccpsl_list,
431 optval + sizeof(service),
432 optlen - sizeof(service)) ||
433 dccp_list_has_service(sl, DCCP_SERVICE_INVALID_VALUE)) {
434 kfree(sl);
435 return -EFAULT;
436 }
437 }
438
439 lock_sock(sk);
440 dp->dccps_service = service;
441
442 kfree(dp->dccps_service_list);
443
444 dp->dccps_service_list = sl;
445 release_sock(sk);
446 return 0;
447 }
448
dccp_setsockopt_cscov(struct sock * sk,int cscov,bool rx)449 static int dccp_setsockopt_cscov(struct sock *sk, int cscov, bool rx)
450 {
451 u8 *list, len;
452 int i, rc;
453
454 if (cscov < 0 || cscov > 15)
455 return -EINVAL;
456 /*
457 * Populate a list of permissible values, in the range cscov...15. This
458 * is necessary since feature negotiation of single values only works if
459 * both sides incidentally choose the same value. Since the list starts
460 * lowest-value first, negotiation will pick the smallest shared value.
461 */
462 if (cscov == 0)
463 return 0;
464 len = 16 - cscov;
465
466 list = kmalloc(len, GFP_KERNEL);
467 if (list == NULL)
468 return -ENOBUFS;
469
470 for (i = 0; i < len; i++)
471 list[i] = cscov++;
472
473 rc = dccp_feat_register_sp(sk, DCCPF_MIN_CSUM_COVER, rx, list, len);
474
475 if (rc == 0) {
476 if (rx)
477 dccp_sk(sk)->dccps_pcrlen = cscov;
478 else
479 dccp_sk(sk)->dccps_pcslen = cscov;
480 }
481 kfree(list);
482 return rc;
483 }
484
dccp_setsockopt_ccid(struct sock * sk,int type,char __user * optval,unsigned int optlen)485 static int dccp_setsockopt_ccid(struct sock *sk, int type,
486 char __user *optval, unsigned int optlen)
487 {
488 u8 *val;
489 int rc = 0;
490
491 if (optlen < 1 || optlen > DCCP_FEAT_MAX_SP_VALS)
492 return -EINVAL;
493
494 val = memdup_user(optval, optlen);
495 if (IS_ERR(val))
496 return PTR_ERR(val);
497
498 lock_sock(sk);
499 if (type == DCCP_SOCKOPT_TX_CCID || type == DCCP_SOCKOPT_CCID)
500 rc = dccp_feat_register_sp(sk, DCCPF_CCID, 1, val, optlen);
501
502 if (!rc && (type == DCCP_SOCKOPT_RX_CCID || type == DCCP_SOCKOPT_CCID))
503 rc = dccp_feat_register_sp(sk, DCCPF_CCID, 0, val, optlen);
504 release_sock(sk);
505
506 kfree(val);
507 return rc;
508 }
509
do_dccp_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen)510 static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
511 char __user *optval, unsigned int optlen)
512 {
513 struct dccp_sock *dp = dccp_sk(sk);
514 int val, err = 0;
515
516 switch (optname) {
517 case DCCP_SOCKOPT_PACKET_SIZE:
518 DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n");
519 return 0;
520 case DCCP_SOCKOPT_CHANGE_L:
521 case DCCP_SOCKOPT_CHANGE_R:
522 DCCP_WARN("sockopt(CHANGE_L/R) is deprecated: fix your app\n");
523 return 0;
524 case DCCP_SOCKOPT_CCID:
525 case DCCP_SOCKOPT_RX_CCID:
526 case DCCP_SOCKOPT_TX_CCID:
527 return dccp_setsockopt_ccid(sk, optname, optval, optlen);
528 }
529
530 if (optlen < (int)sizeof(int))
531 return -EINVAL;
532
533 if (get_user(val, (int __user *)optval))
534 return -EFAULT;
535
536 if (optname == DCCP_SOCKOPT_SERVICE)
537 return dccp_setsockopt_service(sk, val, optval, optlen);
538
539 lock_sock(sk);
540 switch (optname) {
541 case DCCP_SOCKOPT_SERVER_TIMEWAIT:
542 if (dp->dccps_role != DCCP_ROLE_SERVER)
543 err = -EOPNOTSUPP;
544 else
545 dp->dccps_server_timewait = (val != 0);
546 break;
547 case DCCP_SOCKOPT_SEND_CSCOV:
548 err = dccp_setsockopt_cscov(sk, val, false);
549 break;
550 case DCCP_SOCKOPT_RECV_CSCOV:
551 err = dccp_setsockopt_cscov(sk, val, true);
552 break;
553 case DCCP_SOCKOPT_QPOLICY_ID:
554 if (sk->sk_state != DCCP_CLOSED)
555 err = -EISCONN;
556 else if (val < 0 || val >= DCCPQ_POLICY_MAX)
557 err = -EINVAL;
558 else
559 dp->dccps_qpolicy = val;
560 break;
561 case DCCP_SOCKOPT_QPOLICY_TXQLEN:
562 if (val < 0)
563 err = -EINVAL;
564 else
565 dp->dccps_tx_qlen = val;
566 break;
567 default:
568 err = -ENOPROTOOPT;
569 break;
570 }
571 release_sock(sk);
572
573 return err;
574 }
575
dccp_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen)576 int dccp_setsockopt(struct sock *sk, int level, int optname,
577 char __user *optval, unsigned int optlen)
578 {
579 if (level != SOL_DCCP)
580 return inet_csk(sk)->icsk_af_ops->setsockopt(sk, level,
581 optname, optval,
582 optlen);
583 return do_dccp_setsockopt(sk, level, optname, optval, optlen);
584 }
585
586 EXPORT_SYMBOL_GPL(dccp_setsockopt);
587
588 #ifdef CONFIG_COMPAT
compat_dccp_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen)589 int compat_dccp_setsockopt(struct sock *sk, int level, int optname,
590 char __user *optval, unsigned int optlen)
591 {
592 if (level != SOL_DCCP)
593 return inet_csk_compat_setsockopt(sk, level, optname,
594 optval, optlen);
595 return do_dccp_setsockopt(sk, level, optname, optval, optlen);
596 }
597
598 EXPORT_SYMBOL_GPL(compat_dccp_setsockopt);
599 #endif
600
dccp_getsockopt_service(struct sock * sk,int len,__be32 __user * optval,int __user * optlen)601 static int dccp_getsockopt_service(struct sock *sk, int len,
602 __be32 __user *optval,
603 int __user *optlen)
604 {
605 const struct dccp_sock *dp = dccp_sk(sk);
606 const struct dccp_service_list *sl;
607 int err = -ENOENT, slen = 0, total_len = sizeof(u32);
608
609 lock_sock(sk);
610 if ((sl = dp->dccps_service_list) != NULL) {
611 slen = sl->dccpsl_nr * sizeof(u32);
612 total_len += slen;
613 }
614
615 err = -EINVAL;
616 if (total_len > len)
617 goto out;
618
619 err = 0;
620 if (put_user(total_len, optlen) ||
621 put_user(dp->dccps_service, optval) ||
622 (sl != NULL && copy_to_user(optval + 1, sl->dccpsl_list, slen)))
623 err = -EFAULT;
624 out:
625 release_sock(sk);
626 return err;
627 }
628
do_dccp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)629 static int do_dccp_getsockopt(struct sock *sk, int level, int optname,
630 char __user *optval, int __user *optlen)
631 {
632 struct dccp_sock *dp;
633 int val, len;
634
635 if (get_user(len, optlen))
636 return -EFAULT;
637
638 if (len < (int)sizeof(int))
639 return -EINVAL;
640
641 dp = dccp_sk(sk);
642
643 switch (optname) {
644 case DCCP_SOCKOPT_PACKET_SIZE:
645 DCCP_WARN("sockopt(PACKET_SIZE) is deprecated: fix your app\n");
646 return 0;
647 case DCCP_SOCKOPT_SERVICE:
648 return dccp_getsockopt_service(sk, len,
649 (__be32 __user *)optval, optlen);
650 case DCCP_SOCKOPT_GET_CUR_MPS:
651 val = READ_ONCE(dp->dccps_mss_cache);
652 break;
653 case DCCP_SOCKOPT_AVAILABLE_CCIDS:
654 return ccid_getsockopt_builtin_ccids(sk, len, optval, optlen);
655 case DCCP_SOCKOPT_TX_CCID:
656 val = ccid_get_current_tx_ccid(dp);
657 if (val < 0)
658 return -ENOPROTOOPT;
659 break;
660 case DCCP_SOCKOPT_RX_CCID:
661 val = ccid_get_current_rx_ccid(dp);
662 if (val < 0)
663 return -ENOPROTOOPT;
664 break;
665 case DCCP_SOCKOPT_SERVER_TIMEWAIT:
666 val = dp->dccps_server_timewait;
667 break;
668 case DCCP_SOCKOPT_SEND_CSCOV:
669 val = dp->dccps_pcslen;
670 break;
671 case DCCP_SOCKOPT_RECV_CSCOV:
672 val = dp->dccps_pcrlen;
673 break;
674 case DCCP_SOCKOPT_QPOLICY_ID:
675 val = dp->dccps_qpolicy;
676 break;
677 case DCCP_SOCKOPT_QPOLICY_TXQLEN:
678 val = dp->dccps_tx_qlen;
679 break;
680 case 128 ... 191:
681 return ccid_hc_rx_getsockopt(dp->dccps_hc_rx_ccid, sk, optname,
682 len, (u32 __user *)optval, optlen);
683 case 192 ... 255:
684 return ccid_hc_tx_getsockopt(dp->dccps_hc_tx_ccid, sk, optname,
685 len, (u32 __user *)optval, optlen);
686 default:
687 return -ENOPROTOOPT;
688 }
689
690 len = sizeof(val);
691 if (put_user(len, optlen) || copy_to_user(optval, &val, len))
692 return -EFAULT;
693
694 return 0;
695 }
696
dccp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)697 int dccp_getsockopt(struct sock *sk, int level, int optname,
698 char __user *optval, int __user *optlen)
699 {
700 if (level != SOL_DCCP)
701 return inet_csk(sk)->icsk_af_ops->getsockopt(sk, level,
702 optname, optval,
703 optlen);
704 return do_dccp_getsockopt(sk, level, optname, optval, optlen);
705 }
706
707 EXPORT_SYMBOL_GPL(dccp_getsockopt);
708
709 #ifdef CONFIG_COMPAT
compat_dccp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)710 int compat_dccp_getsockopt(struct sock *sk, int level, int optname,
711 char __user *optval, int __user *optlen)
712 {
713 if (level != SOL_DCCP)
714 return inet_csk_compat_getsockopt(sk, level, optname,
715 optval, optlen);
716 return do_dccp_getsockopt(sk, level, optname, optval, optlen);
717 }
718
719 EXPORT_SYMBOL_GPL(compat_dccp_getsockopt);
720 #endif
721
dccp_msghdr_parse(struct msghdr * msg,struct sk_buff * skb)722 static int dccp_msghdr_parse(struct msghdr *msg, struct sk_buff *skb)
723 {
724 struct cmsghdr *cmsg;
725
726 /*
727 * Assign an (opaque) qpolicy priority value to skb->priority.
728 *
729 * We are overloading this skb field for use with the qpolicy subystem.
730 * The skb->priority is normally used for the SO_PRIORITY option, which
731 * is initialised from sk_priority. Since the assignment of sk_priority
732 * to skb->priority happens later (on layer 3), we overload this field
733 * for use with queueing priorities as long as the skb is on layer 4.
734 * The default priority value (if nothing is set) is 0.
735 */
736 skb->priority = 0;
737
738 for_each_cmsghdr(cmsg, msg) {
739 if (!CMSG_OK(msg, cmsg))
740 return -EINVAL;
741
742 if (cmsg->cmsg_level != SOL_DCCP)
743 continue;
744
745 if (cmsg->cmsg_type <= DCCP_SCM_QPOLICY_MAX &&
746 !dccp_qpolicy_param_ok(skb->sk, cmsg->cmsg_type))
747 return -EINVAL;
748
749 switch (cmsg->cmsg_type) {
750 case DCCP_SCM_PRIORITY:
751 if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u32)))
752 return -EINVAL;
753 skb->priority = *(__u32 *)CMSG_DATA(cmsg);
754 break;
755 default:
756 return -EINVAL;
757 }
758 }
759 return 0;
760 }
761
dccp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)762 int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
763 {
764 const struct dccp_sock *dp = dccp_sk(sk);
765 const int flags = msg->msg_flags;
766 const int noblock = flags & MSG_DONTWAIT;
767 struct sk_buff *skb;
768 int rc, size;
769 long timeo;
770
771 trace_dccp_probe(sk, len);
772
773 if (len > READ_ONCE(dp->dccps_mss_cache))
774 return -EMSGSIZE;
775
776 lock_sock(sk);
777
778 timeo = sock_sndtimeo(sk, noblock);
779
780 /*
781 * We have to use sk_stream_wait_connect here to set sk_write_pending,
782 * so that the trick in dccp_rcv_request_sent_state_process.
783 */
784 /* Wait for a connection to finish. */
785 if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
786 if ((rc = sk_stream_wait_connect(sk, &timeo)) != 0)
787 goto out_release;
788
789 size = sk->sk_prot->max_header + len;
790 release_sock(sk);
791 skb = sock_alloc_send_skb(sk, size, noblock, &rc);
792 lock_sock(sk);
793 if (skb == NULL)
794 goto out_release;
795
796 if (dccp_qpolicy_full(sk)) {
797 rc = -EAGAIN;
798 goto out_discard;
799 }
800
801 if (sk->sk_state == DCCP_CLOSED) {
802 rc = -ENOTCONN;
803 goto out_discard;
804 }
805
806 /* We need to check dccps_mss_cache after socket is locked. */
807 if (len > dp->dccps_mss_cache) {
808 rc = -EMSGSIZE;
809 goto out_discard;
810 }
811
812 skb_reserve(skb, sk->sk_prot->max_header);
813 rc = memcpy_from_msg(skb_put(skb, len), msg, len);
814 if (rc != 0)
815 goto out_discard;
816
817 rc = dccp_msghdr_parse(msg, skb);
818 if (rc != 0)
819 goto out_discard;
820
821 dccp_qpolicy_push(sk, skb);
822 /*
823 * The xmit_timer is set if the TX CCID is rate-based and will expire
824 * when congestion control permits to release further packets into the
825 * network. Window-based CCIDs do not use this timer.
826 */
827 if (!timer_pending(&dp->dccps_xmit_timer))
828 dccp_write_xmit(sk);
829 out_release:
830 release_sock(sk);
831 return rc ? : len;
832 out_discard:
833 kfree_skb(skb);
834 goto out_release;
835 }
836
837 EXPORT_SYMBOL_GPL(dccp_sendmsg);
838
dccp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int nonblock,int flags,int * addr_len)839 int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
840 int flags, int *addr_len)
841 {
842 const struct dccp_hdr *dh;
843 long timeo;
844
845 lock_sock(sk);
846
847 if (sk->sk_state == DCCP_LISTEN) {
848 len = -ENOTCONN;
849 goto out;
850 }
851
852 timeo = sock_rcvtimeo(sk, nonblock);
853
854 do {
855 struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
856
857 if (skb == NULL)
858 goto verify_sock_status;
859
860 dh = dccp_hdr(skb);
861
862 switch (dh->dccph_type) {
863 case DCCP_PKT_DATA:
864 case DCCP_PKT_DATAACK:
865 goto found_ok_skb;
866
867 case DCCP_PKT_CLOSE:
868 case DCCP_PKT_CLOSEREQ:
869 if (!(flags & MSG_PEEK))
870 dccp_finish_passive_close(sk);
871 /* fall through */
872 case DCCP_PKT_RESET:
873 dccp_pr_debug("found fin (%s) ok!\n",
874 dccp_packet_name(dh->dccph_type));
875 len = 0;
876 goto found_fin_ok;
877 default:
878 dccp_pr_debug("packet_type=%s\n",
879 dccp_packet_name(dh->dccph_type));
880 sk_eat_skb(sk, skb);
881 }
882 verify_sock_status:
883 if (sock_flag(sk, SOCK_DONE)) {
884 len = 0;
885 break;
886 }
887
888 if (sk->sk_err) {
889 len = sock_error(sk);
890 break;
891 }
892
893 if (sk->sk_shutdown & RCV_SHUTDOWN) {
894 len = 0;
895 break;
896 }
897
898 if (sk->sk_state == DCCP_CLOSED) {
899 if (!sock_flag(sk, SOCK_DONE)) {
900 /* This occurs when user tries to read
901 * from never connected socket.
902 */
903 len = -ENOTCONN;
904 break;
905 }
906 len = 0;
907 break;
908 }
909
910 if (!timeo) {
911 len = -EAGAIN;
912 break;
913 }
914
915 if (signal_pending(current)) {
916 len = sock_intr_errno(timeo);
917 break;
918 }
919
920 sk_wait_data(sk, &timeo, NULL);
921 continue;
922 found_ok_skb:
923 if (len > skb->len)
924 len = skb->len;
925 else if (len < skb->len)
926 msg->msg_flags |= MSG_TRUNC;
927
928 if (skb_copy_datagram_msg(skb, 0, msg, len)) {
929 /* Exception. Bailout! */
930 len = -EFAULT;
931 break;
932 }
933 if (flags & MSG_TRUNC)
934 len = skb->len;
935 found_fin_ok:
936 if (!(flags & MSG_PEEK))
937 sk_eat_skb(sk, skb);
938 break;
939 } while (1);
940 out:
941 release_sock(sk);
942 return len;
943 }
944
945 EXPORT_SYMBOL_GPL(dccp_recvmsg);
946
inet_dccp_listen(struct socket * sock,int backlog)947 int inet_dccp_listen(struct socket *sock, int backlog)
948 {
949 struct sock *sk = sock->sk;
950 unsigned char old_state;
951 int err;
952
953 lock_sock(sk);
954
955 err = -EINVAL;
956 if (sock->state != SS_UNCONNECTED || sock->type != SOCK_DCCP)
957 goto out;
958
959 old_state = sk->sk_state;
960 if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))
961 goto out;
962
963 sk->sk_max_ack_backlog = backlog;
964 /* Really, if the socket is already in listen state
965 * we can only allow the backlog to be adjusted.
966 */
967 if (old_state != DCCP_LISTEN) {
968 /*
969 * FIXME: here it probably should be sk->sk_prot->listen_start
970 * see tcp_listen_start
971 */
972 err = dccp_listen_start(sk, backlog);
973 if (err)
974 goto out;
975 }
976 err = 0;
977
978 out:
979 release_sock(sk);
980 return err;
981 }
982
983 EXPORT_SYMBOL_GPL(inet_dccp_listen);
984
dccp_terminate_connection(struct sock * sk)985 static void dccp_terminate_connection(struct sock *sk)
986 {
987 u8 next_state = DCCP_CLOSED;
988
989 switch (sk->sk_state) {
990 case DCCP_PASSIVE_CLOSE:
991 case DCCP_PASSIVE_CLOSEREQ:
992 dccp_finish_passive_close(sk);
993 break;
994 case DCCP_PARTOPEN:
995 dccp_pr_debug("Stop PARTOPEN timer (%p)\n", sk);
996 inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
997 /* fall through */
998 case DCCP_OPEN:
999 dccp_send_close(sk, 1);
1000
1001 if (dccp_sk(sk)->dccps_role == DCCP_ROLE_SERVER &&
1002 !dccp_sk(sk)->dccps_server_timewait)
1003 next_state = DCCP_ACTIVE_CLOSEREQ;
1004 else
1005 next_state = DCCP_CLOSING;
1006 /* fall through */
1007 default:
1008 dccp_set_state(sk, next_state);
1009 }
1010 }
1011
dccp_close(struct sock * sk,long timeout)1012 void dccp_close(struct sock *sk, long timeout)
1013 {
1014 struct dccp_sock *dp = dccp_sk(sk);
1015 struct sk_buff *skb;
1016 u32 data_was_unread = 0;
1017 int state;
1018
1019 lock_sock(sk);
1020
1021 sk->sk_shutdown = SHUTDOWN_MASK;
1022
1023 if (sk->sk_state == DCCP_LISTEN) {
1024 dccp_set_state(sk, DCCP_CLOSED);
1025
1026 /* Special case. */
1027 inet_csk_listen_stop(sk);
1028
1029 goto adjudge_to_death;
1030 }
1031
1032 sk_stop_timer(sk, &dp->dccps_xmit_timer);
1033
1034 /*
1035 * We need to flush the recv. buffs. We do this only on the
1036 * descriptor close, not protocol-sourced closes, because the
1037 *reader process may not have drained the data yet!
1038 */
1039 while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
1040 data_was_unread += skb->len;
1041 __kfree_skb(skb);
1042 }
1043
1044 /* If socket has been already reset kill it. */
1045 if (sk->sk_state == DCCP_CLOSED)
1046 goto adjudge_to_death;
1047
1048 if (data_was_unread) {
1049 /* Unread data was tossed, send an appropriate Reset Code */
1050 DCCP_WARN("ABORT with %u bytes unread\n", data_was_unread);
1051 dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
1052 dccp_set_state(sk, DCCP_CLOSED);
1053 } else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
1054 /* Check zero linger _after_ checking for unread data. */
1055 sk->sk_prot->disconnect(sk, 0);
1056 } else if (sk->sk_state != DCCP_CLOSED) {
1057 /*
1058 * Normal connection termination. May need to wait if there are
1059 * still packets in the TX queue that are delayed by the CCID.
1060 */
1061 dccp_flush_write_queue(sk, &timeout);
1062 dccp_terminate_connection(sk);
1063 }
1064
1065 /*
1066 * Flush write queue. This may be necessary in several cases:
1067 * - we have been closed by the peer but still have application data;
1068 * - abortive termination (unread data or zero linger time),
1069 * - normal termination but queue could not be flushed within time limit
1070 */
1071 __skb_queue_purge(&sk->sk_write_queue);
1072
1073 sk_stream_wait_close(sk, timeout);
1074
1075 adjudge_to_death:
1076 state = sk->sk_state;
1077 sock_hold(sk);
1078 sock_orphan(sk);
1079
1080 /*
1081 * It is the last release_sock in its life. It will remove backlog.
1082 */
1083 release_sock(sk);
1084 /*
1085 * Now socket is owned by kernel and we acquire BH lock
1086 * to finish close. No need to check for user refs.
1087 */
1088 local_bh_disable();
1089 bh_lock_sock(sk);
1090 WARN_ON(sock_owned_by_user(sk));
1091
1092 percpu_counter_inc(sk->sk_prot->orphan_count);
1093
1094 /* Have we already been destroyed by a softirq or backlog? */
1095 if (state != DCCP_CLOSED && sk->sk_state == DCCP_CLOSED)
1096 goto out;
1097
1098 if (sk->sk_state == DCCP_CLOSED)
1099 inet_csk_destroy_sock(sk);
1100
1101 /* Otherwise, socket is reprieved until protocol close. */
1102
1103 out:
1104 bh_unlock_sock(sk);
1105 local_bh_enable();
1106 sock_put(sk);
1107 }
1108
1109 EXPORT_SYMBOL_GPL(dccp_close);
1110
dccp_shutdown(struct sock * sk,int how)1111 void dccp_shutdown(struct sock *sk, int how)
1112 {
1113 dccp_pr_debug("called shutdown(%x)\n", how);
1114 }
1115
1116 EXPORT_SYMBOL_GPL(dccp_shutdown);
1117
dccp_mib_init(void)1118 static inline int __init dccp_mib_init(void)
1119 {
1120 dccp_statistics = alloc_percpu(struct dccp_mib);
1121 if (!dccp_statistics)
1122 return -ENOMEM;
1123 return 0;
1124 }
1125
dccp_mib_exit(void)1126 static inline void dccp_mib_exit(void)
1127 {
1128 free_percpu(dccp_statistics);
1129 }
1130
1131 static int thash_entries;
1132 module_param(thash_entries, int, 0444);
1133 MODULE_PARM_DESC(thash_entries, "Number of ehash buckets");
1134
1135 #ifdef CONFIG_IP_DCCP_DEBUG
1136 bool dccp_debug;
1137 module_param(dccp_debug, bool, 0644);
1138 MODULE_PARM_DESC(dccp_debug, "Enable debug messages");
1139
1140 EXPORT_SYMBOL_GPL(dccp_debug);
1141 #endif
1142
dccp_init(void)1143 static int __init dccp_init(void)
1144 {
1145 unsigned long goal;
1146 unsigned long nr_pages = totalram_pages();
1147 int ehash_order, bhash_order, i;
1148 int rc;
1149
1150 BUILD_BUG_ON(sizeof(struct dccp_skb_cb) >
1151 FIELD_SIZEOF(struct sk_buff, cb));
1152 rc = percpu_counter_init(&dccp_orphan_count, 0, GFP_KERNEL);
1153 if (rc)
1154 goto out_fail;
1155 inet_hashinfo_init(&dccp_hashinfo);
1156 rc = inet_hashinfo2_init_mod(&dccp_hashinfo);
1157 if (rc)
1158 goto out_free_percpu;
1159 rc = -ENOBUFS;
1160 dccp_hashinfo.bind_bucket_cachep =
1161 kmem_cache_create("dccp_bind_bucket",
1162 sizeof(struct inet_bind_bucket), 0,
1163 SLAB_HWCACHE_ALIGN, NULL);
1164 if (!dccp_hashinfo.bind_bucket_cachep)
1165 goto out_free_hashinfo2;
1166
1167 /*
1168 * Size and allocate the main established and bind bucket
1169 * hash tables.
1170 *
1171 * The methodology is similar to that of the buffer cache.
1172 */
1173 if (nr_pages >= (128 * 1024))
1174 goal = nr_pages >> (21 - PAGE_SHIFT);
1175 else
1176 goal = nr_pages >> (23 - PAGE_SHIFT);
1177
1178 if (thash_entries)
1179 goal = (thash_entries *
1180 sizeof(struct inet_ehash_bucket)) >> PAGE_SHIFT;
1181 for (ehash_order = 0; (1UL << ehash_order) < goal; ehash_order++)
1182 ;
1183 do {
1184 unsigned long hash_size = (1UL << ehash_order) * PAGE_SIZE /
1185 sizeof(struct inet_ehash_bucket);
1186
1187 while (hash_size & (hash_size - 1))
1188 hash_size--;
1189 dccp_hashinfo.ehash_mask = hash_size - 1;
1190 dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
1191 __get_free_pages(GFP_ATOMIC|__GFP_NOWARN, ehash_order);
1192 } while (!dccp_hashinfo.ehash && --ehash_order > 0);
1193
1194 if (!dccp_hashinfo.ehash) {
1195 DCCP_CRIT("Failed to allocate DCCP established hash table");
1196 goto out_free_bind_bucket_cachep;
1197 }
1198
1199 for (i = 0; i <= dccp_hashinfo.ehash_mask; i++)
1200 INIT_HLIST_NULLS_HEAD(&dccp_hashinfo.ehash[i].chain, i);
1201
1202 if (inet_ehash_locks_alloc(&dccp_hashinfo))
1203 goto out_free_dccp_ehash;
1204
1205 bhash_order = ehash_order;
1206
1207 do {
1208 dccp_hashinfo.bhash_size = (1UL << bhash_order) * PAGE_SIZE /
1209 sizeof(struct inet_bind_hashbucket);
1210 if ((dccp_hashinfo.bhash_size > (64 * 1024)) &&
1211 bhash_order > 0)
1212 continue;
1213 dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
1214 __get_free_pages(GFP_ATOMIC|__GFP_NOWARN, bhash_order);
1215 } while (!dccp_hashinfo.bhash && --bhash_order >= 0);
1216
1217 if (!dccp_hashinfo.bhash) {
1218 DCCP_CRIT("Failed to allocate DCCP bind hash table");
1219 goto out_free_dccp_locks;
1220 }
1221
1222 for (i = 0; i < dccp_hashinfo.bhash_size; i++) {
1223 spin_lock_init(&dccp_hashinfo.bhash[i].lock);
1224 INIT_HLIST_HEAD(&dccp_hashinfo.bhash[i].chain);
1225 }
1226
1227 rc = dccp_mib_init();
1228 if (rc)
1229 goto out_free_dccp_bhash;
1230
1231 rc = dccp_ackvec_init();
1232 if (rc)
1233 goto out_free_dccp_mib;
1234
1235 rc = dccp_sysctl_init();
1236 if (rc)
1237 goto out_ackvec_exit;
1238
1239 rc = ccid_initialize_builtins();
1240 if (rc)
1241 goto out_sysctl_exit;
1242
1243 dccp_timestamping_init();
1244
1245 return 0;
1246
1247 out_sysctl_exit:
1248 dccp_sysctl_exit();
1249 out_ackvec_exit:
1250 dccp_ackvec_exit();
1251 out_free_dccp_mib:
1252 dccp_mib_exit();
1253 out_free_dccp_bhash:
1254 free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order);
1255 out_free_dccp_locks:
1256 inet_ehash_locks_free(&dccp_hashinfo);
1257 out_free_dccp_ehash:
1258 free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order);
1259 out_free_bind_bucket_cachep:
1260 kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
1261 out_free_hashinfo2:
1262 inet_hashinfo2_free_mod(&dccp_hashinfo);
1263 out_free_percpu:
1264 percpu_counter_destroy(&dccp_orphan_count);
1265 out_fail:
1266 dccp_hashinfo.bhash = NULL;
1267 dccp_hashinfo.ehash = NULL;
1268 dccp_hashinfo.bind_bucket_cachep = NULL;
1269 return rc;
1270 }
1271
dccp_fini(void)1272 static void __exit dccp_fini(void)
1273 {
1274 ccid_cleanup_builtins();
1275 dccp_mib_exit();
1276 free_pages((unsigned long)dccp_hashinfo.bhash,
1277 get_order(dccp_hashinfo.bhash_size *
1278 sizeof(struct inet_bind_hashbucket)));
1279 free_pages((unsigned long)dccp_hashinfo.ehash,
1280 get_order((dccp_hashinfo.ehash_mask + 1) *
1281 sizeof(struct inet_ehash_bucket)));
1282 inet_ehash_locks_free(&dccp_hashinfo);
1283 kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
1284 dccp_ackvec_exit();
1285 dccp_sysctl_exit();
1286 inet_hashinfo2_free_mod(&dccp_hashinfo);
1287 percpu_counter_destroy(&dccp_orphan_count);
1288 }
1289
1290 module_init(dccp_init);
1291 module_exit(dccp_fini);
1292
1293 MODULE_LICENSE("GPL");
1294 MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@conectiva.com.br>");
1295 MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");
1296