3 * Transmission Control Protocol for IP
5 * This file contains common functions for the TCP implementation, such as functinos
6 * for manipulating the data structures and the TCP timer functions. TCP functions
7 * related to input and output is found in tcp_in.c and tcp_out.c respectively.
12 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
13 * All rights reserved.
15 * Redistribution and use in source and binary forms, with or without modification,
16 * are permitted provided that the following conditions are met:
18 * 1. Redistributions of source code must retain the above copyright notice,
19 * this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright notice,
21 * this list of conditions and the following disclaimer in the documentation
22 * and/or other materials provided with the distribution.
23 * 3. The name of the author may not be used to endorse or promote products
24 * derived from this software without specific prior written permission.
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
27 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
28 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
29 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
30 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
31 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
34 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
37 * This file is part of the lwIP TCP/IP stack.
39 * Author: Adam Dunkels <adam@sics.se>
45 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
49 #include "lwip/memp.h"
50 #include "lwip/snmp.h"
55 /* Incremented every coarse grained timer shot (typically every 500 ms). */
57 const u8_t tcp_backoff[13] =
58 { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
59 /* Times per slowtmr hits */
60 const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 };
62 /* The TCP PCB lists. */
64 /** List of all TCP PCBs bound but not yet (connected || listening) */
65 struct tcp_pcb *tcp_bound_pcbs;
66 /** List of all TCP PCBs in LISTEN state */
67 union tcp_listen_pcbs_t tcp_listen_pcbs;
68 /** List of all TCP PCBs that are in a state in which
69 * they accept or send data. */
70 struct tcp_pcb *tcp_active_pcbs;
71 /** List of all TCP PCBs in TIME-WAIT state */
72 struct tcp_pcb *tcp_tw_pcbs;
74 struct tcp_pcb *tcp_tmp_pcb;
76 static u8_t tcp_timer;
77 static u16_t tcp_new_port(void);
80 * Called periodically to dispatch TCP timers.
86 /* Call tcp_fasttmr() every 250 ms */
89 if (++tcp_timer & 1) {
90 /* Call tcp_tmr() every 500 ms, i.e., every other timer
91 tcp_tmr() is called. */
97 * Closes the connection held by the PCB.
99 * Listening pcbs are freed and may not be referenced any more.
100 * Connection pcbs are freed if not yet connected and may not be referenced
101 * any more. If a connection is established (at least SYN received or in
102 * a closing state), the connection is closed, and put in a closing state.
103 * The pcb is then automatically freed in tcp_slowtmr(). It is therefore
104 * unsafe to reference it.
106 * @param pcb the tcp_pcb to close
107 * @return ERR_OK if connection has been closed
108 * another err_t if closing failed and pcb is not freed
111 tcp_close(struct tcp_pcb *pcb)
116 LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
117 tcp_debug_print_state(pcb->state);
118 #endif /* TCP_DEBUG */
120 switch (pcb->state) {
122 /* Closing a pcb in the CLOSED state might seem erroneous,
123 * however, it is in this state once allocated and as yet unused
124 * and the user needs some way to free it should the need arise.
125 * Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
126 * or for a pcb that has been used and then entered the CLOSED state
127 * is erroneous, but this should never happen as the pcb has in those cases
128 * been freed, and so any remaining handles are bogus. */
130 TCP_RMV(&tcp_bound_pcbs, pcb);
131 memp_free(MEMP_TCP_PCB, pcb);
136 tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs.pcbs, pcb);
137 memp_free(MEMP_TCP_PCB_LISTEN, pcb);
142 tcp_pcb_remove(&tcp_active_pcbs, pcb);
143 memp_free(MEMP_TCP_PCB, pcb);
145 snmp_inc_tcpattemptfails();
148 err = tcp_send_ctrl(pcb, TCP_FIN);
150 snmp_inc_tcpattemptfails();
151 pcb->state = FIN_WAIT_1;
155 err = tcp_send_ctrl(pcb, TCP_FIN);
157 snmp_inc_tcpestabresets();
158 pcb->state = FIN_WAIT_1;
162 err = tcp_send_ctrl(pcb, TCP_FIN);
164 snmp_inc_tcpestabresets();
165 pcb->state = LAST_ACK;
169 /* Has already been closed, do nothing. */
175 if (pcb != NULL && err == ERR_OK) {
176 /* To ensure all data has been sent when tcp_close returns, we have
177 to make sure tcp_output doesn't fail.
178 Since we don't really have to ensure all data has been sent when tcp_close
179 returns (unsent data is sent from tcp timer functions, also), we don't care
180 for the return value of tcp_output for now. */
181 /* @todo: When implementing SO_LINGER, this must be changed somehow:
182 If SOF_LINGER is set, the data should be sent when tcp_close returns. */
189 * Abandons a connection and optionally sends a RST to the remote
190 * host. Deletes the local protocol control block. This is done when
191 * a connection is killed because of shortage of memory.
193 * @param pcb the tcp_pcb to abort
194 * @param reset boolean to indicate whether a reset should be sent
197 tcp_abandon(struct tcp_pcb *pcb, int reset)
200 u16_t remote_port, local_port;
201 struct ip_addr remote_ip, local_ip;
202 #if LWIP_CALLBACK_API
203 void (* errf)(void *arg, err_t err);
204 #endif /* LWIP_CALLBACK_API */
208 /* Figure out on which TCP PCB list we are, and remove us. If we
209 are in an active state, call the receive function associated with
210 the PCB with a NULL argument, and send an RST to the remote end. */
211 if (pcb->state == TIME_WAIT) {
212 tcp_pcb_remove(&tcp_tw_pcbs, pcb);
213 memp_free(MEMP_TCP_PCB, pcb);
215 seqno = pcb->snd_nxt;
216 ackno = pcb->rcv_nxt;
217 ip_addr_set(&local_ip, &(pcb->local_ip));
218 ip_addr_set(&remote_ip, &(pcb->remote_ip));
219 local_port = pcb->local_port;
220 remote_port = pcb->remote_port;
221 #if LWIP_CALLBACK_API
223 #endif /* LWIP_CALLBACK_API */
224 errf_arg = pcb->callback_arg;
225 tcp_pcb_remove(&tcp_active_pcbs, pcb);
226 if (pcb->unacked != NULL) {
227 tcp_segs_free(pcb->unacked);
229 if (pcb->unsent != NULL) {
230 tcp_segs_free(pcb->unsent);
233 if (pcb->ooseq != NULL) {
234 tcp_segs_free(pcb->ooseq);
236 #endif /* TCP_QUEUE_OOSEQ */
237 memp_free(MEMP_TCP_PCB, pcb);
238 TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
240 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
241 tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
247 * Binds the connection to a local portnumber and IP address. If the
248 * IP address is not given (i.e., ipaddr == NULL), the IP address of
249 * the outgoing network interface is used instead.
251 * @param pcb the tcp_pcb to bind (no check is done whether this pcb is
253 * @param ipaddr the local ip address to bind to (use IP_ADDR_ANY to bind
254 * to any local address
255 * @param port the local port to bind to
256 * @return ERR_USE if the port is already in use
260 tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
262 struct tcp_pcb *cpcb;
264 LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
267 port = tcp_new_port();
269 /* Check if the address already is in use. */
270 /* Check the listen pcbs. */
271 for(cpcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs;
272 cpcb != NULL; cpcb = cpcb->next) {
273 if (cpcb->local_port == port) {
274 if (ip_addr_isany(&(cpcb->local_ip)) ||
275 ip_addr_isany(ipaddr) ||
276 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
281 /* Check the connected pcbs. */
282 for(cpcb = tcp_active_pcbs;
283 cpcb != NULL; cpcb = cpcb->next) {
284 if (cpcb->local_port == port) {
285 if (ip_addr_isany(&(cpcb->local_ip)) ||
286 ip_addr_isany(ipaddr) ||
287 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
292 /* Check the bound, not yet connected pcbs. */
293 for(cpcb = tcp_bound_pcbs; cpcb != NULL; cpcb = cpcb->next) {
294 if (cpcb->local_port == port) {
295 if (ip_addr_isany(&(cpcb->local_ip)) ||
296 ip_addr_isany(ipaddr) ||
297 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
302 /* @todo: until SO_REUSEADDR is implemented (see task #6995 on savannah),
303 * we have to check the pcbs in TIME-WAIT state, also: */
304 for(cpcb = tcp_tw_pcbs; cpcb != NULL; cpcb = cpcb->next) {
305 if (cpcb->local_port == port) {
306 if (ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
312 if (!ip_addr_isany(ipaddr)) {
313 pcb->local_ip = *ipaddr;
315 pcb->local_port = port;
316 TCP_REG(&tcp_bound_pcbs, pcb);
317 LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
320 #if LWIP_CALLBACK_API
322 * Default accept callback if no accept callback is specified by the user.
325 tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
327 LWIP_UNUSED_ARG(arg);
328 LWIP_UNUSED_ARG(pcb);
329 LWIP_UNUSED_ARG(err);
333 #endif /* LWIP_CALLBACK_API */
336 * Set the state of the connection to be LISTEN, which means that it
337 * is able to accept incoming connections. The protocol control block
338 * is reallocated in order to consume less memory. Setting the
339 * connection to LISTEN is an irreversible process.
341 * @param pcb the original tcp_pcb
342 * @param backlog the incoming connections queue limit
343 * @return tcp_pcb used for listening, consumes less memory.
345 * @note The original tcp_pcb is freed. This function therefore has to be
347 * tpcb = tcp_listen(tpcb);
350 tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
352 struct tcp_pcb_listen *lpcb;
354 LWIP_UNUSED_ARG(backlog);
355 LWIP_ERROR("tcp_listen: pcb already connected", pcb->state == CLOSED, return NULL);
357 /* already listening? */
358 if (pcb->state == LISTEN) {
361 lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
365 lpcb->callback_arg = pcb->callback_arg;
366 lpcb->local_port = pcb->local_port;
367 lpcb->state = LISTEN;
368 lpcb->so_options = pcb->so_options;
369 lpcb->so_options |= SOF_ACCEPTCONN;
370 lpcb->ttl = pcb->ttl;
371 lpcb->tos = pcb->tos;
372 ip_addr_set(&lpcb->local_ip, &pcb->local_ip);
373 TCP_RMV(&tcp_bound_pcbs, pcb);
374 memp_free(MEMP_TCP_PCB, pcb);
375 #if LWIP_CALLBACK_API
376 lpcb->accept = tcp_accept_null;
377 #endif /* LWIP_CALLBACK_API */
378 #if TCP_LISTEN_BACKLOG
379 lpcb->accepts_pending = 0;
380 lpcb->backlog = (backlog ? backlog : 1);
381 #endif /* TCP_LISTEN_BACKLOG */
382 TCP_REG(&tcp_listen_pcbs.listen_pcbs, lpcb);
383 return (struct tcp_pcb *)lpcb;
387 * This function should be called by the application when it has
388 * processed the data. The purpose is to advertise a larger window
389 * when the data has been processed.
391 * @param pcb the tcp_pcb for which data is read
392 * @param len the amount of bytes that have been read by the application
395 tcp_recved(struct tcp_pcb *pcb, u16_t len)
397 if ((u32_t)pcb->rcv_wnd + len > TCP_WND) {
398 pcb->rcv_wnd = TCP_WND;
399 pcb->rcv_ann_wnd = TCP_WND;
402 if (pcb->rcv_wnd >= pcb->mss) {
403 pcb->rcv_ann_wnd = pcb->rcv_wnd;
407 if (!(pcb->flags & TF_ACK_DELAY) &&
408 !(pcb->flags & TF_ACK_NOW)) {
410 * We send an ACK here (if one is not already pending, hence
411 * the above tests) as tcp_recved() implies that the application
412 * has processed some data, and so we can open the receiver's
413 * window to allow more to be transmitted. This could result in
414 * two ACKs being sent for each received packet in some limited cases
415 * (where the application is only receiving data, and is slow to
416 * process it) but it is necessary to guarantee that the sender can
417 * continue to transmit.
421 else if (pcb->flags & TF_ACK_DELAY && pcb->rcv_wnd >= TCP_WND/2) {
422 /* If we can send a window update such that there is a full
423 * segment available in the window, do so now. This is sort of
424 * nagle-like in its goals, and tries to hit a compromise between
425 * sending acks each time the window is updated, and only sending
426 * window updates when a timer expires. The "threshold" used
427 * above (currently TCP_WND/2) can be tuned to be more or less
432 LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n",
433 len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
437 * A nastly hack featuring 'goto' statements that allocates a
438 * new TCP local port.
440 * @return a new (free) local TCP port number
446 #ifndef TCP_LOCAL_PORT_RANGE_START
447 #define TCP_LOCAL_PORT_RANGE_START 4096
448 #define TCP_LOCAL_PORT_RANGE_END 0x7fff
450 static u16_t port = TCP_LOCAL_PORT_RANGE_START;
453 if (++port > TCP_LOCAL_PORT_RANGE_END) {
454 port = TCP_LOCAL_PORT_RANGE_START;
457 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
458 if (pcb->local_port == port) {
462 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
463 if (pcb->local_port == port) {
467 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
468 if (pcb->local_port == port) {
476 * Connects to another host. The function given as the "connected"
477 * argument will be called when the connection has been established.
479 * @param pcb the tcp_pcb used to establish the connection
480 * @param ipaddr the remote ip address to connect to
481 * @param port the remote tcp port to connect to
482 * @param connected callback function to call when connected (or on error)
483 * @return ERR_VAL if invalid arguments are given
484 * ERR_OK if connect request has been sent
485 * other err_t values if connect request couldn't be sent
488 tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port,
489 err_t (* connected)(void *arg, struct tcp_pcb *tpcb, err_t err))
495 LWIP_ERROR("tcp_connect: can only connected from state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
497 LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
498 if (ipaddr != NULL) {
499 pcb->remote_ip = *ipaddr;
503 pcb->remote_port = port;
504 if (pcb->local_port == 0) {
505 pcb->local_port = tcp_new_port();
507 iss = tcp_next_iss();
510 pcb->lastack = iss - 1;
511 pcb->snd_lbb = iss - 1;
512 pcb->rcv_wnd = TCP_WND;
513 pcb->rcv_ann_wnd = TCP_WND;
514 pcb->snd_wnd = TCP_WND;
515 /* As initial send MSS, we use TCP_MSS but limit it to 536.
516 The send MSS is updated when an MSS option is received. */
517 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
518 #if TCP_CALCULATE_EFF_SEND_MSS
519 pcb->mss = tcp_eff_send_mss(pcb->mss, ipaddr);
520 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
522 pcb->ssthresh = pcb->mss * 10;
523 pcb->state = SYN_SENT;
524 #if LWIP_CALLBACK_API
525 pcb->connected = connected;
526 #endif /* LWIP_CALLBACK_API */
527 TCP_RMV(&tcp_bound_pcbs, pcb);
528 TCP_REG(&tcp_active_pcbs, pcb);
530 snmp_inc_tcpactiveopens();
532 /* Build an MSS option */
533 optdata = TCP_BUILD_MSS_OPTION();
535 ret = tcp_enqueue(pcb, NULL, 0, TCP_SYN, 0, (u8_t *)&optdata, 4);
543 * Called every 500 ms and implements the retransmission timer and the timer that
544 * removes PCBs that have been in TIME-WAIT for enough time. It also increments
545 * various timers such as the inactivity timer in each PCB.
547 * Automatically called from tcp_tmr().
552 struct tcp_pcb *pcb, *pcb2, *prev;
554 u8_t pcb_remove; /* flag if a PCB should be removed */
561 /* Steps through all of the active PCBs. */
563 pcb = tcp_active_pcbs;
565 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
567 while (pcb != NULL) {
568 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
569 LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
570 LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
571 LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
575 if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
577 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
579 else if (pcb->nrtx == TCP_MAXRTX) {
581 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
583 if (pcb->persist_backoff > 0) {
584 /* If snd_wnd is zero, use persist timer to send 1 byte probes
585 * instead of using the standard retransmission mechanism. */
587 if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1]) {
588 pcb->persist_cnt = 0;
589 if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) {
590 pcb->persist_backoff++;
592 tcp_zero_window_probe(pcb);
595 /* Increase the retransmission timer if it is running */
599 if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
600 /* Time for a retransmission. */
601 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"S16_F
602 " pcb->rto %"S16_F"\n",
603 pcb->rtime, pcb->rto));
605 /* Double retransmission time-out unless we are trying to
606 * connect to somebody (i.e., we are in SYN_SENT). */
607 if (pcb->state != SYN_SENT) {
608 pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
611 /* Reset the retransmission timer. */
614 /* Reduce congestion window and ssthresh. */
615 eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
616 pcb->ssthresh = eff_wnd >> 1;
617 if (pcb->ssthresh < pcb->mss) {
618 pcb->ssthresh = pcb->mss * 2;
620 pcb->cwnd = pcb->mss;
621 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F
622 " ssthresh %"U16_F"\n",
623 pcb->cwnd, pcb->ssthresh));
625 /* The following needs to be called AFTER cwnd is set to one
631 /* Check if this PCB has stayed too long in FIN-WAIT-2 */
632 if (pcb->state == FIN_WAIT_2) {
633 if ((u32_t)(tcp_ticks - pcb->tmr) >
634 TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
636 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
640 /* Check if KEEPALIVE should be sent */
641 if((pcb->so_options & SOF_KEEPALIVE) &&
642 ((pcb->state == ESTABLISHED) ||
643 (pcb->state == CLOSE_WAIT))) {
644 #if LWIP_TCP_KEEPALIVE
645 if((u32_t)(tcp_ticks - pcb->tmr) >
646 (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl))
649 if((u32_t)(tcp_ticks - pcb->tmr) >
650 (pcb->keep_idle + TCP_MAXIDLE) / TCP_SLOW_INTERVAL)
651 #endif /* LWIP_TCP_KEEPALIVE */
653 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n",
654 ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip),
655 ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip)));
659 #if LWIP_TCP_KEEPALIVE
660 else if((u32_t)(tcp_ticks - pcb->tmr) >
661 (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl)
664 else if((u32_t)(tcp_ticks - pcb->tmr) >
665 (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT)
667 #endif /* LWIP_TCP_KEEPALIVE */
670 pcb->keep_cnt_sent++;
674 /* If this PCB has queued out of sequence data, but has been
675 inactive for too long, will drop the data (it will eventually
676 be retransmitted). */
678 if (pcb->ooseq != NULL &&
679 (u32_t)tcp_ticks - pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) {
680 tcp_segs_free(pcb->ooseq);
682 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
684 #endif /* TCP_QUEUE_OOSEQ */
686 /* Check if this PCB has stayed too long in SYN-RCVD */
687 if (pcb->state == SYN_RCVD) {
688 if ((u32_t)(tcp_ticks - pcb->tmr) >
689 TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
691 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
695 /* Check if this PCB has stayed too long in LAST-ACK */
696 if (pcb->state == LAST_ACK) {
697 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
699 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
703 /* If the PCB should be removed, do it. */
706 /* Remove PCB from tcp_active_pcbs list. */
708 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
709 prev->next = pcb->next;
711 /* This PCB was the first. */
712 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
713 tcp_active_pcbs = pcb->next;
716 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
719 memp_free(MEMP_TCP_PCB, pcb);
723 /* We check if we should poll the connection. */
725 if (pcb->polltmr >= pcb->pollinterval) {
727 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
728 TCP_EVENT_POLL(pcb, err);
740 /* Steps through all of the TIME-WAIT PCBs. */
743 while (pcb != NULL) {
744 LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
747 /* Check if this PCB has stayed long enough in TIME-WAIT */
748 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
754 /* If the PCB should be removed, do it. */
757 /* Remove PCB from tcp_tw_pcbs list. */
759 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
760 prev->next = pcb->next;
762 /* This PCB was the first. */
763 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
764 tcp_tw_pcbs = pcb->next;
767 memp_free(MEMP_TCP_PCB, pcb);
777 * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously
778 * "refused" by upper layer (application) and sends delayed ACKs.
780 * Automatically called from tcp_tmr().
787 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
788 /* If there is data which was previously "refused" by upper layer */
789 if (pcb->refused_data != NULL) {
790 /* Notify again application with data previously received. */
792 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n"));
793 TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
795 pcb->refused_data = NULL;
799 /* send delayed ACKs */
800 if (pcb->flags & TF_ACK_DELAY) {
801 LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
803 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
809 * Deallocates a list of TCP segments (tcp_seg structures).
811 * @param seg tcp_seg list of TCP segments to free
812 * @return the number of pbufs that were deallocated
815 tcp_segs_free(struct tcp_seg *seg)
818 struct tcp_seg *next;
819 while (seg != NULL) {
821 count += tcp_seg_free(seg);
828 * Frees a TCP segment (tcp_seg structure).
830 * @param seg single tcp_seg to free
831 * @return the number of pbufs that were deallocated
834 tcp_seg_free(struct tcp_seg *seg)
839 if (seg->p != NULL) {
840 count = pbuf_free(seg->p);
843 #endif /* TCP_DEBUG */
845 memp_free(MEMP_TCP_SEG, seg);
851 * Sets the priority of a connection.
853 * @param pcb the tcp_pcb to manipulate
854 * @param prio new priority
857 tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
864 * Returns a copy of the given TCP segment.
865 * The pbuf and data are not copied, only the pointers
867 * @param seg the old tcp_seg
868 * @return a copy of seg
871 tcp_seg_copy(struct tcp_seg *seg)
873 struct tcp_seg *cseg;
875 cseg = memp_malloc(MEMP_TCP_SEG);
879 SMEMCPY((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg));
885 #if LWIP_CALLBACK_API
887 * Default receive callback that is called if the user didn't register
888 * a recv callback for the pcb.
891 tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
896 } else if (err == ERR_OK) {
897 return tcp_close(pcb);
901 #endif /* LWIP_CALLBACK_API */
904 * Kills the oldest active connection that has lower priority than prio.
906 * @param prio minimum priority
909 tcp_kill_prio(u8_t prio)
911 struct tcp_pcb *pcb, *inactive;
916 mprio = TCP_PRIO_MAX;
918 /* We kill the oldest active connection that has lower priority than prio. */
921 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
922 if (pcb->prio <= prio &&
923 pcb->prio <= mprio &&
924 (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
925 inactivity = tcp_ticks - pcb->tmr;
930 if (inactive != NULL) {
931 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
932 (void *)inactive, inactivity));
938 * Kills the oldest connection that is in TIME_WAIT state.
939 * Called from tcp_alloc() if no more connections are available.
942 tcp_kill_timewait(void)
944 struct tcp_pcb *pcb, *inactive;
949 /* Go through the list of TIME_WAIT pcbs and get the oldest pcb. */
950 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
951 if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
952 inactivity = tcp_ticks - pcb->tmr;
956 if (inactive != NULL) {
957 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
958 (void *)inactive, inactivity));
964 * Allocate a new tcp_pcb structure.
966 * @param prio priority for the new pcb
967 * @return a new tcp_pcb that initially is in state CLOSED
975 pcb = memp_malloc(MEMP_TCP_PCB);
977 /* Try killing oldest connection in TIME-WAIT. */
978 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
980 /* Try to allocate a tcp_pcb again. */
981 pcb = memp_malloc(MEMP_TCP_PCB);
983 /* Try killing active connections with lower priority than the new one. */
985 /* Try to allocate a tcp_pcb again. */
986 pcb = memp_malloc(MEMP_TCP_PCB);
990 memset(pcb, 0, sizeof(struct tcp_pcb));
991 pcb->prio = TCP_PRIO_NORMAL;
992 pcb->snd_buf = TCP_SND_BUF;
993 pcb->snd_queuelen = 0;
994 pcb->rcv_wnd = TCP_WND;
995 pcb->rcv_ann_wnd = TCP_WND;
998 /* As initial send MSS, we use TCP_MSS but limit it to 536.
999 The send MSS is updated when an MSS option is received. */
1000 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
1001 pcb->rto = 3000 / TCP_SLOW_INTERVAL;
1003 pcb->sv = 3000 / TCP_SLOW_INTERVAL;
1006 iss = tcp_next_iss();
1012 pcb->tmr = tcp_ticks;
1016 #if LWIP_CALLBACK_API
1017 pcb->recv = tcp_recv_null;
1018 #endif /* LWIP_CALLBACK_API */
1020 /* Init KEEPALIVE timer */
1021 pcb->keep_idle = TCP_KEEPIDLE_DEFAULT;
1023 #if LWIP_TCP_KEEPALIVE
1024 pcb->keep_intvl = TCP_KEEPINTVL_DEFAULT;
1025 pcb->keep_cnt = TCP_KEEPCNT_DEFAULT;
1026 #endif /* LWIP_TCP_KEEPALIVE */
1028 pcb->keep_cnt_sent = 0;
1034 * Creates a new TCP protocol control block but doesn't place it on
1035 * any of the TCP PCB lists.
1036 * The pcb is not put on any list until binding using tcp_bind().
1038 * @internal: Maybe there should be a idle TCP PCB list where these
1039 * PCBs are put on. Port reservation using tcp_bind() is implemented but
1040 * allocated pcbs that are not bound can't be killed automatically if wanting
1041 * to allocate a pcb with higher prio (@see tcp_kill_prio())
1043 * @return a new tcp_pcb that initially is in state CLOSED
1048 return tcp_alloc(TCP_PRIO_NORMAL);
1052 * Used to specify the argument that should be passed callback
1055 * @param pcb tcp_pcb to set the callback argument
1056 * @param arg void pointer argument to pass to callback functions
1059 tcp_arg(struct tcp_pcb *pcb, void *arg)
1061 pcb->callback_arg = arg;
1063 #if LWIP_CALLBACK_API
1066 * Used to specify the function that should be called when a TCP
1067 * connection receives data.
1069 * @param pcb tcp_pcb to set the recv callback
1070 * @param recv callback function to call for this pcb when data is received
1073 tcp_recv(struct tcp_pcb *pcb,
1074 err_t (* recv)(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err))
1080 * Used to specify the function that should be called when TCP data
1081 * has been successfully delivered to the remote host.
1083 * @param pcb tcp_pcb to set the sent callback
1084 * @param sent callback function to call for this pcb when data is successfully sent
1087 tcp_sent(struct tcp_pcb *pcb,
1088 err_t (* sent)(void *arg, struct tcp_pcb *tpcb, u16_t len))
1094 * Used to specify the function that should be called when a fatal error
1095 * has occured on the connection.
1097 * @param pcb tcp_pcb to set the err callback
1098 * @param errf callback function to call for this pcb when a fatal error
1099 * has occured on the connection
1102 tcp_err(struct tcp_pcb *pcb,
1103 void (* errf)(void *arg, err_t err))
1109 * Used for specifying the function that should be called when a
1110 * LISTENing connection has been connected to another host.
1112 * @param pcb tcp_pcb to set the accept callback
1113 * @param accept callback function to call for this pcb when LISTENing
1114 * connection has been connected to another host
1117 tcp_accept(struct tcp_pcb *pcb,
1118 err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err))
1120 pcb->accept = accept;
1122 #endif /* LWIP_CALLBACK_API */
1126 * Used to specify the function that should be called periodically
1127 * from TCP. The interval is specified in terms of the TCP coarse
1128 * timer interval, which is called twice a second.
1132 tcp_poll(struct tcp_pcb *pcb,
1133 err_t (* poll)(void *arg, struct tcp_pcb *tpcb), u8_t interval)
1135 #if LWIP_CALLBACK_API
1137 #endif /* LWIP_CALLBACK_API */
1138 pcb->pollinterval = interval;
1142 * Purges a TCP PCB. Removes any buffered data and frees the buffer memory
1143 * (pcb->ooseq, pcb->unsent and pcb->unacked are freed).
1145 * @param pcb tcp_pcb to purge. The pcb itself is not deallocated!
1148 tcp_pcb_purge(struct tcp_pcb *pcb)
1150 if (pcb->state != CLOSED &&
1151 pcb->state != TIME_WAIT &&
1152 pcb->state != LISTEN) {
1154 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
1156 #if TCP_LISTEN_BACKLOG
1157 if (pcb->state == SYN_RCVD) {
1158 /* Need to find the corresponding listen_pcb and decrease its accepts_pending */
1159 struct tcp_pcb_listen *lpcb;
1160 LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL",
1161 tcp_listen_pcbs.listen_pcbs != NULL);
1162 for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
1163 if ((lpcb->local_port == pcb->local_port) &&
1164 (ip_addr_isany(&lpcb->local_ip) ||
1165 ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) {
1166 /* port and address of the listen pcb match the timed-out pcb */
1167 LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending",
1168 lpcb->accepts_pending > 0);
1169 lpcb->accepts_pending--;
1174 #endif /* TCP_LISTEN_BACKLOG */
1177 if (pcb->refused_data != NULL) {
1178 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n"));
1179 pbuf_free(pcb->refused_data);
1180 pcb->refused_data = NULL;
1182 if (pcb->unsent != NULL) {
1183 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
1185 if (pcb->unacked != NULL) {
1186 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
1188 #if TCP_QUEUE_OOSEQ /* LW */
1189 if (pcb->ooseq != NULL) {
1190 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
1193 /* Stop the retransmission timer as it will expect data on unacked
1194 queue if it fires */
1197 tcp_segs_free(pcb->ooseq);
1199 #endif /* TCP_QUEUE_OOSEQ */
1200 tcp_segs_free(pcb->unsent);
1201 tcp_segs_free(pcb->unacked);
1202 pcb->unacked = pcb->unsent = NULL;
1207 * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
1209 * @param pcblist PCB list to purge.
1210 * @param pcb tcp_pcb to purge. The pcb itself is also deallocated!
1213 tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
1215 TCP_RMV(pcblist, pcb);
1219 /* if there is an outstanding delayed ACKs, send it */
1220 if (pcb->state != TIME_WAIT &&
1221 pcb->state != LISTEN &&
1222 pcb->flags & TF_ACK_DELAY) {
1223 pcb->flags |= TF_ACK_NOW;
1227 if (pcb->state != LISTEN) {
1228 LWIP_ASSERT("unsent segments leaking", pcb->unsent == NULL);
1229 LWIP_ASSERT("unacked segments leaking", pcb->unacked == NULL);
1231 LWIP_ASSERT("ooseq segments leaking", pcb->ooseq == NULL);
1232 #endif /* TCP_QUEUE_OOSEQ */
1235 pcb->state = CLOSED;
1237 LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
1241 * Calculates a new initial sequence number for new connections.
1243 * @return u32_t pseudo random sequence number
1248 static u32_t iss = 6510;
1250 iss += tcp_ticks; /* XXX */
1254 #if TCP_CALCULATE_EFF_SEND_MSS
1256 * Calcluates the effective send mss that can be used for a specific IP address
1257 * by using ip_route to determin the netif used to send to the address and
1258 * calculating the minimum of TCP_MSS and that netif's mtu (if set).
1261 tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr)
1264 struct netif *outif;
1266 outif = ip_route(addr);
1267 if ((outif != NULL) && (outif->mtu != 0)) {
1268 mss_s = outif->mtu - IP_HLEN - TCP_HLEN;
1269 /* RFC 1122, chap 4.2.2.6:
1270 * Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize
1271 * but we only send options with SYN and that is never filled with data! */
1272 sendmss = LWIP_MIN(sendmss, mss_s);
1276 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
1278 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
1280 * Print a tcp header for debugging purposes.
1282 * @param tcphdr pointer to a struct tcp_hdr
1285 tcp_debug_print(struct tcp_hdr *tcphdr)
1287 LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n"));
1288 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1289 LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n",
1290 ntohs(tcphdr->src), ntohs(tcphdr->dest)));
1291 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1292 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n",
1293 ntohl(tcphdr->seqno)));
1294 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1295 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n",
1296 ntohl(tcphdr->ackno)));
1297 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1298 LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (",
1299 TCPH_HDRLEN(tcphdr),
1300 TCPH_FLAGS(tcphdr) >> 5 & 1,
1301 TCPH_FLAGS(tcphdr) >> 4 & 1,
1302 TCPH_FLAGS(tcphdr) >> 3 & 1,
1303 TCPH_FLAGS(tcphdr) >> 2 & 1,
1304 TCPH_FLAGS(tcphdr) >> 1 & 1,
1305 TCPH_FLAGS(tcphdr) & 1,
1306 ntohs(tcphdr->wnd)));
1307 tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
1308 LWIP_DEBUGF(TCP_DEBUG, ("), win)\n"));
1309 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1310 LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n",
1311 ntohs(tcphdr->chksum), ntohs(tcphdr->urgp)));
1312 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1316 * Print a tcp state for debugging purposes.
1318 * @param s enum tcp_state to print
1321 tcp_debug_print_state(enum tcp_state s)
1323 LWIP_DEBUGF(TCP_DEBUG, ("State: "));
1326 LWIP_DEBUGF(TCP_DEBUG, ("CLOSED\n"));
1329 LWIP_DEBUGF(TCP_DEBUG, ("LISTEN\n"));
1332 LWIP_DEBUGF(TCP_DEBUG, ("SYN_SENT\n"));
1335 LWIP_DEBUGF(TCP_DEBUG, ("SYN_RCVD\n"));
1338 LWIP_DEBUGF(TCP_DEBUG, ("ESTABLISHED\n"));
1341 LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_1\n"));
1344 LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_2\n"));
1347 LWIP_DEBUGF(TCP_DEBUG, ("CLOSE_WAIT\n"));
1350 LWIP_DEBUGF(TCP_DEBUG, ("CLOSING\n"));
1353 LWIP_DEBUGF(TCP_DEBUG, ("LAST_ACK\n"));
1356 LWIP_DEBUGF(TCP_DEBUG, ("TIME_WAIT\n"));
1362 * Print tcp flags for debugging purposes.
1364 * @param flags tcp flags, all active flags are printed
1367 tcp_debug_print_flags(u8_t flags)
1369 if (flags & TCP_FIN) {
1370 LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
1372 if (flags & TCP_SYN) {
1373 LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
1375 if (flags & TCP_RST) {
1376 LWIP_DEBUGF(TCP_DEBUG, ("RST "));
1378 if (flags & TCP_PSH) {
1379 LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
1381 if (flags & TCP_ACK) {
1382 LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
1384 if (flags & TCP_URG) {
1385 LWIP_DEBUGF(TCP_DEBUG, ("URG "));
1387 if (flags & TCP_ECE) {
1388 LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
1390 if (flags & TCP_CWR) {
1391 LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
1396 * Print all tcp_pcbs in every list for debugging purposes.
1399 tcp_debug_print_pcbs(void)
1401 struct tcp_pcb *pcb;
1402 LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
1403 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1404 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1405 pcb->local_port, pcb->remote_port,
1406 pcb->snd_nxt, pcb->rcv_nxt));
1407 tcp_debug_print_state(pcb->state);
1409 LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
1410 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
1411 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1412 pcb->local_port, pcb->remote_port,
1413 pcb->snd_nxt, pcb->rcv_nxt));
1414 tcp_debug_print_state(pcb->state);
1416 LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
1417 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1418 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1419 pcb->local_port, pcb->remote_port,
1420 pcb->snd_nxt, pcb->rcv_nxt));
1421 tcp_debug_print_state(pcb->state);
1426 * Check state consistency of the tcp_pcb lists.
1431 struct tcp_pcb *pcb;
1432 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1433 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
1434 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
1435 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
1437 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1438 LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
1442 #endif /* TCP_DEBUG */
1444 #endif /* LWIP_TCP */