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"
52 #include "lwip/debug.h"
53 #include "lwip/stats.h"
57 const char *tcp_state_str[] = {
71 /* Incremented every coarse grained timer shot (typically every 500 ms). */
73 const u8_t tcp_backoff[13] =
74 { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
75 /* Times per slowtmr hits */
76 const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 };
78 /* The TCP PCB lists. */
80 /** List of all TCP PCBs bound but not yet (connected || listening) */
81 struct tcp_pcb *tcp_bound_pcbs;
82 /** List of all TCP PCBs in LISTEN state */
83 union tcp_listen_pcbs_t tcp_listen_pcbs;
84 /** List of all TCP PCBs that are in a state in which
85 * they accept or send data. */
86 struct tcp_pcb *tcp_active_pcbs;
87 /** List of all TCP PCBs in TIME-WAIT state */
88 struct tcp_pcb *tcp_tw_pcbs;
90 struct tcp_pcb *tcp_tmp_pcb;
92 static u8_t tcp_timer;
93 static u16_t tcp_new_port(void);
96 * Called periodically to dispatch TCP timers.
102 /* Call tcp_fasttmr() every 250 ms */
105 if (++tcp_timer & 1) {
106 /* Call tcp_tmr() every 500 ms, i.e., every other timer
107 tcp_tmr() is called. */
113 * Closes the connection held by the PCB.
115 * Listening pcbs are freed and may not be referenced any more.
116 * Connection pcbs are freed if not yet connected and may not be referenced
117 * any more. If a connection is established (at least SYN received or in
118 * a closing state), the connection is closed, and put in a closing state.
119 * The pcb is then automatically freed in tcp_slowtmr(). It is therefore
120 * unsafe to reference it.
122 * @param pcb the tcp_pcb to close
123 * @return ERR_OK if connection has been closed
124 * another err_t if closing failed and pcb is not freed
127 tcp_close(struct tcp_pcb *pcb)
132 LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in "));
133 tcp_debug_print_state(pcb->state);
134 #endif /* TCP_DEBUG */
136 switch (pcb->state) {
138 /* Closing a pcb in the CLOSED state might seem erroneous,
139 * however, it is in this state once allocated and as yet unused
140 * and the user needs some way to free it should the need arise.
141 * Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
142 * or for a pcb that has been used and then entered the CLOSED state
143 * is erroneous, but this should never happen as the pcb has in those cases
144 * been freed, and so any remaining handles are bogus. */
146 TCP_RMV(&tcp_bound_pcbs, pcb);
147 memp_free(MEMP_TCP_PCB, pcb);
152 tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs.pcbs, pcb);
153 memp_free(MEMP_TCP_PCB_LISTEN, pcb);
158 tcp_pcb_remove(&tcp_active_pcbs, pcb);
159 memp_free(MEMP_TCP_PCB, pcb);
161 snmp_inc_tcpattemptfails();
164 err = tcp_send_ctrl(pcb, TCP_FIN);
166 snmp_inc_tcpattemptfails();
167 pcb->state = FIN_WAIT_1;
171 err = tcp_send_ctrl(pcb, TCP_FIN);
173 snmp_inc_tcpestabresets();
174 pcb->state = FIN_WAIT_1;
178 err = tcp_send_ctrl(pcb, TCP_FIN);
180 snmp_inc_tcpestabresets();
181 pcb->state = LAST_ACK;
185 /* Has already been closed, do nothing. */
191 if (pcb != NULL && err == ERR_OK) {
192 /* To ensure all data has been sent when tcp_close returns, we have
193 to make sure tcp_output doesn't fail.
194 Since we don't really have to ensure all data has been sent when tcp_close
195 returns (unsent data is sent from tcp timer functions, also), we don't care
196 for the return value of tcp_output for now. */
197 /* @todo: When implementing SO_LINGER, this must be changed somehow:
198 If SOF_LINGER is set, the data should be sent when tcp_close returns. */
205 * Abandons a connection and optionally sends a RST to the remote
206 * host. Deletes the local protocol control block. This is done when
207 * a connection is killed because of shortage of memory.
209 * @param pcb the tcp_pcb to abort
210 * @param reset boolean to indicate whether a reset should be sent
213 tcp_abandon(struct tcp_pcb *pcb, int reset)
216 u16_t remote_port, local_port;
217 struct ip_addr remote_ip, local_ip;
218 #if LWIP_CALLBACK_API
219 void (* errf)(void *arg, err_t err);
220 #endif /* LWIP_CALLBACK_API */
224 /* Figure out on which TCP PCB list we are, and remove us. If we
225 are in an active state, call the receive function associated with
226 the PCB with a NULL argument, and send an RST to the remote end. */
227 if (pcb->state == TIME_WAIT) {
228 tcp_pcb_remove(&tcp_tw_pcbs, pcb);
229 memp_free(MEMP_TCP_PCB, pcb);
231 seqno = pcb->snd_nxt;
232 ackno = pcb->rcv_nxt;
233 ip_addr_set(&local_ip, &(pcb->local_ip));
234 ip_addr_set(&remote_ip, &(pcb->remote_ip));
235 local_port = pcb->local_port;
236 remote_port = pcb->remote_port;
237 #if LWIP_CALLBACK_API
239 #endif /* LWIP_CALLBACK_API */
240 errf_arg = pcb->callback_arg;
241 tcp_pcb_remove(&tcp_active_pcbs, pcb);
242 if (pcb->unacked != NULL) {
243 tcp_segs_free(pcb->unacked);
245 if (pcb->unsent != NULL) {
246 tcp_segs_free(pcb->unsent);
249 if (pcb->ooseq != NULL) {
250 tcp_segs_free(pcb->ooseq);
252 #endif /* TCP_QUEUE_OOSEQ */
253 memp_free(MEMP_TCP_PCB, pcb);
254 TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
256 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n"));
257 tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
263 * Binds the connection to a local portnumber and IP address. If the
264 * IP address is not given (i.e., ipaddr == NULL), the IP address of
265 * the outgoing network interface is used instead.
267 * @param pcb the tcp_pcb to bind (no check is done whether this pcb is
269 * @param ipaddr the local ip address to bind to (use IP_ADDR_ANY to bind
270 * to any local address
271 * @param port the local port to bind to
272 * @return ERR_USE if the port is already in use
276 tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
278 struct tcp_pcb *cpcb;
280 LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
283 port = tcp_new_port();
285 /* Check if the address already is in use. */
286 /* Check the listen pcbs. */
287 for(cpcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs;
288 cpcb != NULL; cpcb = cpcb->next) {
289 if (cpcb->local_port == port) {
290 if (ip_addr_isany(&(cpcb->local_ip)) ||
291 ip_addr_isany(ipaddr) ||
292 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
297 /* Check the connected pcbs. */
298 for(cpcb = tcp_active_pcbs;
299 cpcb != NULL; cpcb = cpcb->next) {
300 if (cpcb->local_port == port) {
301 if (ip_addr_isany(&(cpcb->local_ip)) ||
302 ip_addr_isany(ipaddr) ||
303 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
308 /* Check the bound, not yet connected pcbs. */
309 for(cpcb = tcp_bound_pcbs; cpcb != NULL; cpcb = cpcb->next) {
310 if (cpcb->local_port == port) {
311 if (ip_addr_isany(&(cpcb->local_ip)) ||
312 ip_addr_isany(ipaddr) ||
313 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
318 /* @todo: until SO_REUSEADDR is implemented (see task #6995 on savannah),
319 * we have to check the pcbs in TIME-WAIT state, also: */
320 for(cpcb = tcp_tw_pcbs; cpcb != NULL; cpcb = cpcb->next) {
321 if (cpcb->local_port == port) {
322 if (ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
328 if (!ip_addr_isany(ipaddr)) {
329 pcb->local_ip = *ipaddr;
331 pcb->local_port = port;
332 TCP_REG(&tcp_bound_pcbs, pcb);
333 LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
336 #if LWIP_CALLBACK_API
338 * Default accept callback if no accept callback is specified by the user.
341 tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
343 LWIP_UNUSED_ARG(arg);
344 LWIP_UNUSED_ARG(pcb);
345 LWIP_UNUSED_ARG(err);
349 #endif /* LWIP_CALLBACK_API */
352 * Set the state of the connection to be LISTEN, which means that it
353 * is able to accept incoming connections. The protocol control block
354 * is reallocated in order to consume less memory. Setting the
355 * connection to LISTEN is an irreversible process.
357 * @param pcb the original tcp_pcb
358 * @param backlog the incoming connections queue limit
359 * @return tcp_pcb used for listening, consumes less memory.
361 * @note The original tcp_pcb is freed. This function therefore has to be
363 * tpcb = tcp_listen(tpcb);
366 tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog)
368 struct tcp_pcb_listen *lpcb;
370 LWIP_UNUSED_ARG(backlog);
371 LWIP_ERROR("tcp_listen: pcb already connected", pcb->state == CLOSED, return NULL);
373 /* already listening? */
374 if (pcb->state == LISTEN) {
377 lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
381 lpcb->callback_arg = pcb->callback_arg;
382 lpcb->local_port = pcb->local_port;
383 lpcb->state = LISTEN;
384 lpcb->so_options = pcb->so_options;
385 lpcb->so_options |= SOF_ACCEPTCONN;
386 lpcb->ttl = pcb->ttl;
387 lpcb->tos = pcb->tos;
388 ip_addr_set(&lpcb->local_ip, &pcb->local_ip);
389 TCP_RMV(&tcp_bound_pcbs, pcb);
390 memp_free(MEMP_TCP_PCB, pcb);
391 #if LWIP_CALLBACK_API
392 lpcb->accept = tcp_accept_null;
393 #endif /* LWIP_CALLBACK_API */
394 #if TCP_LISTEN_BACKLOG
395 lpcb->accepts_pending = 0;
396 lpcb->backlog = (backlog ? backlog : 1);
397 #endif /* TCP_LISTEN_BACKLOG */
398 TCP_REG(&tcp_listen_pcbs.listen_pcbs, lpcb);
399 return (struct tcp_pcb *)lpcb;
403 * Update the state that tracks the available window space to advertise.
405 * Returns how much extra window would be advertised if we sent an
408 u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb)
410 u32_t new_right_edge = pcb->rcv_nxt + pcb->rcv_wnd;
412 if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + LWIP_MIN((TCP_WND / 2), pcb->mss))) {
413 /* we can advertise more window */
414 pcb->rcv_ann_wnd = pcb->rcv_wnd;
415 return new_right_edge - pcb->rcv_ann_right_edge;
417 if (TCP_SEQ_GT(pcb->rcv_nxt, pcb->rcv_ann_right_edge)) {
418 /* Can happen due to other end sending out of advertised window,
419 * but within actual available (but not yet advertised) window */
420 pcb->rcv_ann_wnd = 0;
422 /* keep the right edge of window constant */
423 pcb->rcv_ann_wnd = pcb->rcv_ann_right_edge - pcb->rcv_nxt;
430 * This function should be called by the application when it has
431 * processed the data. The purpose is to advertise a larger window
432 * when the data has been processed.
434 * @param pcb the tcp_pcb for which data is read
435 * @param len the amount of bytes that have been read by the application
438 tcp_recved(struct tcp_pcb *pcb, u16_t len)
442 LWIP_ASSERT("tcp_recved: len would wrap rcv_wnd\n",
443 len <= 0xffff - pcb->rcv_wnd );
446 if (pcb->rcv_wnd > TCP_WND)
447 pcb->rcv_wnd = TCP_WND;
449 wnd_inflation = tcp_update_rcv_ann_wnd(pcb);
451 /* If the change in the right edge of window is significant (default
452 * watermark is TCP_WND/2), then send an explicit update now.
453 * Otherwise wait for a packet to be sent in the normal course of
454 * events (or more window to be available later) */
455 if (wnd_inflation >= TCP_WND_UPDATE_THRESHOLD)
458 LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n",
459 len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
463 * A nastly hack featuring 'goto' statements that allocates a
464 * new TCP local port.
466 * @return a new (free) local TCP port number
472 #ifndef TCP_LOCAL_PORT_RANGE_START
473 #define TCP_LOCAL_PORT_RANGE_START 4096
474 #define TCP_LOCAL_PORT_RANGE_END 0x7fff
476 static u16_t port = TCP_LOCAL_PORT_RANGE_START;
479 if (++port > TCP_LOCAL_PORT_RANGE_END) {
480 port = TCP_LOCAL_PORT_RANGE_START;
483 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
484 if (pcb->local_port == port) {
488 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
489 if (pcb->local_port == port) {
493 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
494 if (pcb->local_port == port) {
502 * Connects to another host. The function given as the "connected"
503 * argument will be called when the connection has been established.
505 * @param pcb the tcp_pcb used to establish the connection
506 * @param ipaddr the remote ip address to connect to
507 * @param port the remote tcp port to connect to
508 * @param connected callback function to call when connected (or on error)
509 * @return ERR_VAL if invalid arguments are given
510 * ERR_OK if connect request has been sent
511 * other err_t values if connect request couldn't be sent
514 tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port,
515 err_t (* connected)(void *arg, struct tcp_pcb *tpcb, err_t err))
520 LWIP_ERROR("tcp_connect: can only connected from state CLOSED", pcb->state == CLOSED, return ERR_ISCONN);
522 LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
523 if (ipaddr != NULL) {
524 pcb->remote_ip = *ipaddr;
528 pcb->remote_port = port;
529 if (pcb->local_port == 0) {
530 pcb->local_port = tcp_new_port();
532 iss = tcp_next_iss();
535 pcb->lastack = iss - 1;
536 pcb->snd_lbb = iss - 1;
537 pcb->rcv_wnd = TCP_WND;
538 pcb->rcv_ann_wnd = TCP_WND;
539 pcb->rcv_ann_right_edge = pcb->rcv_nxt;
540 pcb->snd_wnd = TCP_WND;
541 /* As initial send MSS, we use TCP_MSS but limit it to 536.
542 The send MSS is updated when an MSS option is received. */
543 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
544 #if TCP_CALCULATE_EFF_SEND_MSS
545 pcb->mss = tcp_eff_send_mss(pcb->mss, ipaddr);
546 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
548 pcb->ssthresh = pcb->mss * 10;
549 pcb->state = SYN_SENT;
550 #if LWIP_CALLBACK_API
551 pcb->connected = connected;
552 #endif /* LWIP_CALLBACK_API */
553 TCP_RMV(&tcp_bound_pcbs, pcb);
554 TCP_REG(&tcp_active_pcbs, pcb);
556 snmp_inc_tcpactiveopens();
558 ret = tcp_enqueue(pcb, NULL, 0, TCP_SYN, 0, TF_SEG_OPTS_MSS
559 #if LWIP_TCP_TIMESTAMPS
570 * Called every 500 ms and implements the retransmission timer and the timer that
571 * removes PCBs that have been in TIME-WAIT for enough time. It also increments
572 * various timers such as the inactivity timer in each PCB.
574 * Automatically called from tcp_tmr().
579 struct tcp_pcb *pcb, *pcb2, *prev;
581 u8_t pcb_remove; /* flag if a PCB should be removed */
582 u8_t pcb_reset; /* flag if a RST should be sent when removing */
589 /* Steps through all of the active PCBs. */
591 pcb = tcp_active_pcbs;
593 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
595 while (pcb != NULL) {
596 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
597 LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
598 LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
599 LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
604 if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
606 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
608 else if (pcb->nrtx == TCP_MAXRTX) {
610 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
612 if (pcb->persist_backoff > 0) {
613 /* If snd_wnd is zero, use persist timer to send 1 byte probes
614 * instead of using the standard retransmission mechanism. */
616 if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1]) {
617 pcb->persist_cnt = 0;
618 if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) {
619 pcb->persist_backoff++;
621 tcp_zero_window_probe(pcb);
624 /* Increase the retransmission timer if it is running */
628 if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
629 /* Time for a retransmission. */
630 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"S16_F
631 " pcb->rto %"S16_F"\n",
632 pcb->rtime, pcb->rto));
634 /* Double retransmission time-out unless we are trying to
635 * connect to somebody (i.e., we are in SYN_SENT). */
636 if (pcb->state != SYN_SENT) {
637 pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
640 /* Reset the retransmission timer. */
643 /* Reduce congestion window and ssthresh. */
644 eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
645 pcb->ssthresh = eff_wnd >> 1;
646 if (pcb->ssthresh < pcb->mss) {
647 pcb->ssthresh = pcb->mss * 2;
649 pcb->cwnd = pcb->mss;
650 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F
651 " ssthresh %"U16_F"\n",
652 pcb->cwnd, pcb->ssthresh));
654 /* The following needs to be called AFTER cwnd is set to one
660 /* Check if this PCB has stayed too long in FIN-WAIT-2 */
661 if (pcb->state == FIN_WAIT_2) {
662 if ((u32_t)(tcp_ticks - pcb->tmr) >
663 TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
665 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
669 /* Check if KEEPALIVE should be sent */
670 if((pcb->so_options & SOF_KEEPALIVE) &&
671 ((pcb->state == ESTABLISHED) ||
672 (pcb->state == CLOSE_WAIT))) {
673 #if LWIP_TCP_KEEPALIVE
674 if((u32_t)(tcp_ticks - pcb->tmr) >
675 (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl))
678 if((u32_t)(tcp_ticks - pcb->tmr) >
679 (pcb->keep_idle + TCP_MAXIDLE) / TCP_SLOW_INTERVAL)
680 #endif /* LWIP_TCP_KEEPALIVE */
682 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n",
683 ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip),
684 ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip)));
689 #if LWIP_TCP_KEEPALIVE
690 else if((u32_t)(tcp_ticks - pcb->tmr) >
691 (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl)
694 else if((u32_t)(tcp_ticks - pcb->tmr) >
695 (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT)
697 #endif /* LWIP_TCP_KEEPALIVE */
700 pcb->keep_cnt_sent++;
704 /* If this PCB has queued out of sequence data, but has been
705 inactive for too long, will drop the data (it will eventually
706 be retransmitted). */
708 if (pcb->ooseq != NULL &&
709 (u32_t)tcp_ticks - pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) {
710 tcp_segs_free(pcb->ooseq);
712 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
714 #endif /* TCP_QUEUE_OOSEQ */
716 /* Check if this PCB has stayed too long in SYN-RCVD */
717 if (pcb->state == SYN_RCVD) {
718 if ((u32_t)(tcp_ticks - pcb->tmr) >
719 TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
721 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
725 /* Check if this PCB has stayed too long in LAST-ACK */
726 if (pcb->state == LAST_ACK) {
727 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
729 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
733 /* If the PCB should be removed, do it. */
736 /* Remove PCB from tcp_active_pcbs list. */
738 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
739 prev->next = pcb->next;
741 /* This PCB was the first. */
742 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
743 tcp_active_pcbs = pcb->next;
746 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
748 tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip,
749 pcb->local_port, pcb->remote_port);
753 memp_free(MEMP_TCP_PCB, pcb);
757 /* We check if we should poll the connection. */
759 if (pcb->polltmr >= pcb->pollinterval) {
761 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
762 TCP_EVENT_POLL(pcb, err);
774 /* Steps through all of the TIME-WAIT PCBs. */
777 while (pcb != NULL) {
778 LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
781 /* Check if this PCB has stayed long enough in TIME-WAIT */
782 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
788 /* If the PCB should be removed, do it. */
791 /* Remove PCB from tcp_tw_pcbs list. */
793 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
794 prev->next = pcb->next;
796 /* This PCB was the first. */
797 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
798 tcp_tw_pcbs = pcb->next;
801 memp_free(MEMP_TCP_PCB, pcb);
811 * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously
812 * "refused" by upper layer (application) and sends delayed ACKs.
814 * Automatically called from tcp_tmr().
821 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
822 /* If there is data which was previously "refused" by upper layer */
823 if (pcb->refused_data != NULL) {
824 /* Notify again application with data previously received. */
826 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n"));
827 TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
829 pcb->refused_data = NULL;
833 /* send delayed ACKs */
834 if (pcb->flags & TF_ACK_DELAY) {
835 LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
837 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
843 * Deallocates a list of TCP segments (tcp_seg structures).
845 * @param seg tcp_seg list of TCP segments to free
846 * @return the number of pbufs that were deallocated
849 tcp_segs_free(struct tcp_seg *seg)
852 struct tcp_seg *next;
853 while (seg != NULL) {
855 count += tcp_seg_free(seg);
862 * Frees a TCP segment (tcp_seg structure).
864 * @param seg single tcp_seg to free
865 * @return the number of pbufs that were deallocated
868 tcp_seg_free(struct tcp_seg *seg)
873 if (seg->p != NULL) {
874 count = pbuf_free(seg->p);
877 #endif /* TCP_DEBUG */
879 memp_free(MEMP_TCP_SEG, seg);
885 * Sets the priority of a connection.
887 * @param pcb the tcp_pcb to manipulate
888 * @param prio new priority
891 tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
898 * Returns a copy of the given TCP segment.
899 * The pbuf and data are not copied, only the pointers
901 * @param seg the old tcp_seg
902 * @return a copy of seg
905 tcp_seg_copy(struct tcp_seg *seg)
907 struct tcp_seg *cseg;
909 cseg = memp_malloc(MEMP_TCP_SEG);
913 SMEMCPY((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg));
919 #if LWIP_CALLBACK_API
921 * Default receive callback that is called if the user didn't register
922 * a recv callback for the pcb.
925 tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
927 LWIP_UNUSED_ARG(arg);
929 tcp_recved(pcb, p->tot_len);
931 } else if (err == ERR_OK) {
932 return tcp_close(pcb);
936 #endif /* LWIP_CALLBACK_API */
939 * Kills the oldest active connection that has lower priority than prio.
941 * @param prio minimum priority
944 tcp_kill_prio(u8_t prio)
946 struct tcp_pcb *pcb, *inactive;
951 mprio = TCP_PRIO_MAX;
953 /* We kill the oldest active connection that has lower priority than prio. */
956 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
957 if (pcb->prio <= prio &&
958 pcb->prio <= mprio &&
959 (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
960 inactivity = tcp_ticks - pcb->tmr;
965 if (inactive != NULL) {
966 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
967 (void *)inactive, inactivity));
973 * Kills the oldest connection that is in TIME_WAIT state.
974 * Called from tcp_alloc() if no more connections are available.
977 tcp_kill_timewait(void)
979 struct tcp_pcb *pcb, *inactive;
984 /* Go through the list of TIME_WAIT pcbs and get the oldest pcb. */
985 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
986 if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
987 inactivity = tcp_ticks - pcb->tmr;
991 if (inactive != NULL) {
992 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
993 (void *)inactive, inactivity));
999 * Allocate a new tcp_pcb structure.
1001 * @param prio priority for the new pcb
1002 * @return a new tcp_pcb that initially is in state CLOSED
1005 tcp_alloc(u8_t prio)
1007 struct tcp_pcb *pcb;
1010 pcb = memp_malloc(MEMP_TCP_PCB);
1012 /* Try killing oldest connection in TIME-WAIT. */
1013 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
1014 tcp_kill_timewait();
1015 /* Try to allocate a tcp_pcb again. */
1016 pcb = memp_malloc(MEMP_TCP_PCB);
1018 /* Try killing active connections with lower priority than the new one. */
1019 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing connection with prio lower than %d\n", prio));
1020 tcp_kill_prio(prio);
1021 /* Try to allocate a tcp_pcb again. */
1022 pcb = memp_malloc(MEMP_TCP_PCB);
1024 /* adjust err stats: memp_malloc failed twice before */
1025 MEMP_STATS_DEC(err, MEMP_TCP_PCB);
1029 /* adjust err stats: timewait PCB was freed above */
1030 MEMP_STATS_DEC(err, MEMP_TCP_PCB);
1034 memset(pcb, 0, sizeof(struct tcp_pcb));
1035 pcb->prio = TCP_PRIO_NORMAL;
1036 pcb->snd_buf = TCP_SND_BUF;
1037 pcb->snd_queuelen = 0;
1038 pcb->rcv_wnd = TCP_WND;
1039 pcb->rcv_ann_wnd = TCP_WND;
1042 /* As initial send MSS, we use TCP_MSS but limit it to 536.
1043 The send MSS is updated when an MSS option is received. */
1044 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS;
1045 pcb->rto = 3000 / TCP_SLOW_INTERVAL;
1047 pcb->sv = 3000 / TCP_SLOW_INTERVAL;
1050 iss = tcp_next_iss();
1055 pcb->tmr = tcp_ticks;
1059 #if LWIP_CALLBACK_API
1060 pcb->recv = tcp_recv_null;
1061 #endif /* LWIP_CALLBACK_API */
1063 /* Init KEEPALIVE timer */
1064 pcb->keep_idle = TCP_KEEPIDLE_DEFAULT;
1066 #if LWIP_TCP_KEEPALIVE
1067 pcb->keep_intvl = TCP_KEEPINTVL_DEFAULT;
1068 pcb->keep_cnt = TCP_KEEPCNT_DEFAULT;
1069 #endif /* LWIP_TCP_KEEPALIVE */
1071 pcb->keep_cnt_sent = 0;
1077 * Creates a new TCP protocol control block but doesn't place it on
1078 * any of the TCP PCB lists.
1079 * The pcb is not put on any list until binding using tcp_bind().
1081 * @internal: Maybe there should be a idle TCP PCB list where these
1082 * PCBs are put on. Port reservation using tcp_bind() is implemented but
1083 * allocated pcbs that are not bound can't be killed automatically if wanting
1084 * to allocate a pcb with higher prio (@see tcp_kill_prio())
1086 * @return a new tcp_pcb that initially is in state CLOSED
1091 return tcp_alloc(TCP_PRIO_NORMAL);
1095 * Used to specify the argument that should be passed callback
1098 * @param pcb tcp_pcb to set the callback argument
1099 * @param arg void pointer argument to pass to callback functions
1102 tcp_arg(struct tcp_pcb *pcb, void *arg)
1104 pcb->callback_arg = arg;
1106 #if LWIP_CALLBACK_API
1109 * Used to specify the function that should be called when a TCP
1110 * connection receives data.
1112 * @param pcb tcp_pcb to set the recv callback
1113 * @param recv callback function to call for this pcb when data is received
1116 tcp_recv(struct tcp_pcb *pcb,
1117 err_t (* recv)(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err))
1123 * Used to specify the function that should be called when TCP data
1124 * has been successfully delivered to the remote host.
1126 * @param pcb tcp_pcb to set the sent callback
1127 * @param sent callback function to call for this pcb when data is successfully sent
1130 tcp_sent(struct tcp_pcb *pcb,
1131 err_t (* sent)(void *arg, struct tcp_pcb *tpcb, u16_t len))
1137 * Used to specify the function that should be called when a fatal error
1138 * has occured on the connection.
1140 * @param pcb tcp_pcb to set the err callback
1141 * @param errf callback function to call for this pcb when a fatal error
1142 * has occured on the connection
1145 tcp_err(struct tcp_pcb *pcb,
1146 void (* errf)(void *arg, err_t err))
1152 * Used for specifying the function that should be called when a
1153 * LISTENing connection has been connected to another host.
1155 * @param pcb tcp_pcb to set the accept callback
1156 * @param accept callback function to call for this pcb when LISTENing
1157 * connection has been connected to another host
1160 tcp_accept(struct tcp_pcb *pcb,
1161 err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err))
1163 pcb->accept = accept;
1165 #endif /* LWIP_CALLBACK_API */
1169 * Used to specify the function that should be called periodically
1170 * from TCP. The interval is specified in terms of the TCP coarse
1171 * timer interval, which is called twice a second.
1175 tcp_poll(struct tcp_pcb *pcb,
1176 err_t (* poll)(void *arg, struct tcp_pcb *tpcb), u8_t interval)
1178 #if LWIP_CALLBACK_API
1180 #endif /* LWIP_CALLBACK_API */
1181 pcb->pollinterval = interval;
1185 * Purges a TCP PCB. Removes any buffered data and frees the buffer memory
1186 * (pcb->ooseq, pcb->unsent and pcb->unacked are freed).
1188 * @param pcb tcp_pcb to purge. The pcb itself is not deallocated!
1191 tcp_pcb_purge(struct tcp_pcb *pcb)
1193 if (pcb->state != CLOSED &&
1194 pcb->state != TIME_WAIT &&
1195 pcb->state != LISTEN) {
1197 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
1199 #if TCP_LISTEN_BACKLOG
1200 if (pcb->state == SYN_RCVD) {
1201 /* Need to find the corresponding listen_pcb and decrease its accepts_pending */
1202 struct tcp_pcb_listen *lpcb;
1203 LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL",
1204 tcp_listen_pcbs.listen_pcbs != NULL);
1205 for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
1206 if ((lpcb->local_port == pcb->local_port) &&
1207 (ip_addr_isany(&lpcb->local_ip) ||
1208 ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) {
1209 /* port and address of the listen pcb match the timed-out pcb */
1210 LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending",
1211 lpcb->accepts_pending > 0);
1212 lpcb->accepts_pending--;
1217 #endif /* TCP_LISTEN_BACKLOG */
1220 if (pcb->refused_data != NULL) {
1221 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n"));
1222 pbuf_free(pcb->refused_data);
1223 pcb->refused_data = NULL;
1225 if (pcb->unsent != NULL) {
1226 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
1228 if (pcb->unacked != NULL) {
1229 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
1231 #if TCP_QUEUE_OOSEQ /* LW */
1232 if (pcb->ooseq != NULL) {
1233 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
1236 /* Stop the retransmission timer as it will expect data on unacked
1237 queue if it fires */
1240 tcp_segs_free(pcb->ooseq);
1242 #endif /* TCP_QUEUE_OOSEQ */
1243 tcp_segs_free(pcb->unsent);
1244 tcp_segs_free(pcb->unacked);
1245 pcb->unacked = pcb->unsent = NULL;
1250 * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
1252 * @param pcblist PCB list to purge.
1253 * @param pcb tcp_pcb to purge. The pcb itself is NOT deallocated!
1256 tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
1258 TCP_RMV(pcblist, pcb);
1262 /* if there is an outstanding delayed ACKs, send it */
1263 if (pcb->state != TIME_WAIT &&
1264 pcb->state != LISTEN &&
1265 pcb->flags & TF_ACK_DELAY) {
1266 pcb->flags |= TF_ACK_NOW;
1270 if (pcb->state != LISTEN) {
1271 LWIP_ASSERT("unsent segments leaking", pcb->unsent == NULL);
1272 LWIP_ASSERT("unacked segments leaking", pcb->unacked == NULL);
1274 LWIP_ASSERT("ooseq segments leaking", pcb->ooseq == NULL);
1275 #endif /* TCP_QUEUE_OOSEQ */
1278 pcb->state = CLOSED;
1280 LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
1284 * Calculates a new initial sequence number for new connections.
1286 * @return u32_t pseudo random sequence number
1291 static u32_t iss = 6510;
1293 iss += tcp_ticks; /* XXX */
1297 #if TCP_CALCULATE_EFF_SEND_MSS
1299 * Calcluates the effective send mss that can be used for a specific IP address
1300 * by using ip_route to determin the netif used to send to the address and
1301 * calculating the minimum of TCP_MSS and that netif's mtu (if set).
1304 tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr)
1307 struct netif *outif;
1309 outif = ip_route(addr);
1310 if ((outif != NULL) && (outif->mtu != 0)) {
1311 mss_s = outif->mtu - IP_HLEN - TCP_HLEN;
1312 /* RFC 1122, chap 4.2.2.6:
1313 * Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize
1314 * We correct for TCP options in tcp_enqueue(), and don't support
1317 sendmss = LWIP_MIN(sendmss, mss_s);
1321 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
1324 tcp_debug_state_str(enum tcp_state s)
1326 return tcp_state_str[s];
1329 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
1331 * Print a tcp header for debugging purposes.
1333 * @param tcphdr pointer to a struct tcp_hdr
1336 tcp_debug_print(struct tcp_hdr *tcphdr)
1338 LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n"));
1339 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1340 LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n",
1341 ntohs(tcphdr->src), ntohs(tcphdr->dest)));
1342 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1343 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n",
1344 ntohl(tcphdr->seqno)));
1345 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1346 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n",
1347 ntohl(tcphdr->ackno)));
1348 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1349 LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (",
1350 TCPH_HDRLEN(tcphdr),
1351 TCPH_FLAGS(tcphdr) >> 5 & 1,
1352 TCPH_FLAGS(tcphdr) >> 4 & 1,
1353 TCPH_FLAGS(tcphdr) >> 3 & 1,
1354 TCPH_FLAGS(tcphdr) >> 2 & 1,
1355 TCPH_FLAGS(tcphdr) >> 1 & 1,
1356 TCPH_FLAGS(tcphdr) & 1,
1357 ntohs(tcphdr->wnd)));
1358 tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
1359 LWIP_DEBUGF(TCP_DEBUG, ("), win)\n"));
1360 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1361 LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n",
1362 ntohs(tcphdr->chksum), ntohs(tcphdr->urgp)));
1363 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1367 * Print a tcp state for debugging purposes.
1369 * @param s enum tcp_state to print
1372 tcp_debug_print_state(enum tcp_state s)
1374 LWIP_DEBUGF(TCP_DEBUG, ("State: %s\n", tcp_state_str[s]));
1378 * Print tcp flags for debugging purposes.
1380 * @param flags tcp flags, all active flags are printed
1383 tcp_debug_print_flags(u8_t flags)
1385 if (flags & TCP_FIN) {
1386 LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
1388 if (flags & TCP_SYN) {
1389 LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
1391 if (flags & TCP_RST) {
1392 LWIP_DEBUGF(TCP_DEBUG, ("RST "));
1394 if (flags & TCP_PSH) {
1395 LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
1397 if (flags & TCP_ACK) {
1398 LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
1400 if (flags & TCP_URG) {
1401 LWIP_DEBUGF(TCP_DEBUG, ("URG "));
1403 if (flags & TCP_ECE) {
1404 LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
1406 if (flags & TCP_CWR) {
1407 LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
1409 LWIP_DEBUGF(TCP_DEBUG, ("\n"));
1413 * Print all tcp_pcbs in every list for debugging purposes.
1416 tcp_debug_print_pcbs(void)
1418 struct tcp_pcb *pcb;
1419 LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
1420 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1421 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1422 pcb->local_port, pcb->remote_port,
1423 pcb->snd_nxt, pcb->rcv_nxt));
1424 tcp_debug_print_state(pcb->state);
1426 LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
1427 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
1428 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1429 pcb->local_port, pcb->remote_port,
1430 pcb->snd_nxt, pcb->rcv_nxt));
1431 tcp_debug_print_state(pcb->state);
1433 LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
1434 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1435 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1436 pcb->local_port, pcb->remote_port,
1437 pcb->snd_nxt, pcb->rcv_nxt));
1438 tcp_debug_print_state(pcb->state);
1443 * Check state consistency of the tcp_pcb lists.
1448 struct tcp_pcb *pcb;
1449 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1450 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
1451 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
1452 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
1454 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1455 LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
1459 #endif /* TCP_DEBUG */
1461 #endif /* LWIP_TCP */