4 * Transmission Control Protocol for IP
6 * This file contains common functions for the TCP implementation, such as functinos
7 * for manipulating the data structures and the TCP timer functions. TCP functions
8 * related to input and output is found in tcp_in.c and tcp_out.c respectively.
13 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
14 * All rights reserved.
16 * Redistribution and use in source and binary forms, with or without modification,
17 * are permitted provided that the following conditions are met:
19 * 1. Redistributions of source code must retain the above copyright notice,
20 * this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright notice,
22 * this list of conditions and the following disclaimer in the documentation
23 * and/or other materials provided with the distribution.
24 * 3. The name of the author may not be used to endorse or promote products
25 * derived from this software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
30 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
32 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
35 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
38 * This file is part of the lwIP TCP/IP stack.
40 * Author: Adam Dunkels <adam@sics.se>
49 #include "lwip/memp.h"
54 /* Incremented every coarse grained timer shot
55 (typically every 500 ms, determined by TCP_COARSE_TIMEOUT). */
57 const u8_t tcp_backoff[13] =
58 { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
60 /* The TCP PCB lists. */
62 /** List of all TCP PCBs in LISTEN state */
63 union tcp_listen_pcbs_t tcp_listen_pcbs;
64 /** List of all TCP PCBs that are in a state in which
65 * they accept or send data. */
66 struct tcp_pcb *tcp_active_pcbs;
67 /** List of all TCP PCBs in TIME-WAIT state */
68 struct tcp_pcb *tcp_tw_pcbs;
70 struct tcp_pcb *tcp_tmp_pcb;
72 static u8_t tcp_timer;
73 static u16_t tcp_new_port(void);
76 * Initializes the TCP layer.
82 tcp_listen_pcbs.listen_pcbs = NULL;
83 tcp_active_pcbs = NULL;
87 /* initialize timer */
94 * Called periodically to dispatch TCP timers.
100 /* Call tcp_fasttmr() every 250 ms */
103 if (++tcp_timer & 1) {
104 /* Call tcp_tmr() every 500 ms, i.e., every other timer
105 tcp_tmr() is called. */
111 * Closes the connection held by the PCB.
115 tcp_close(struct tcp_pcb *pcb)
120 LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in state "));
121 tcp_debug_print_state(pcb->state);
122 LWIP_DEBUGF(TCP_DEBUG, ("\n"));
123 #endif /* TCP_DEBUG */
124 switch (pcb->state) {
126 /* Closing a pcb in the CLOSED state might seem erroneous,
127 * however, it is in this state once allocated and as yet unused
128 * and the user needs some way to free it should the need arise.
129 * Calling tcp_close() with a pcb that has already been closed, (i.e. twice)
130 * or for a pcb that has been used and then entered the CLOSED state
131 * is erroneous, but this should never happen as the pcb has in those cases
132 * been freed, and so any remaining handles are bogus. */
134 memp_free(MEMP_TCP_PCB, pcb);
139 tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs.pcbs, pcb);
140 memp_free(MEMP_TCP_PCB_LISTEN, pcb);
145 tcp_pcb_remove(&tcp_active_pcbs, pcb);
146 memp_free(MEMP_TCP_PCB, pcb);
151 err = tcp_send_ctrl(pcb, TCP_FIN);
153 pcb->state = FIN_WAIT_1;
157 err = tcp_send_ctrl(pcb, TCP_FIN);
159 pcb->state = LAST_ACK;
163 /* Has already been closed, do nothing. */
169 if (pcb != NULL && err == ERR_OK) {
170 err = tcp_output(pcb);
176 * Aborts a connection by sending a RST to the remote host and deletes
177 * the local protocol control block. This is done when a connection is
178 * killed because of shortage of memory.
182 tcp_abort(struct tcp_pcb *pcb)
185 u16_t remote_port, local_port;
186 struct ip_addr remote_ip, local_ip;
187 #if LWIP_CALLBACK_API
188 void (* errf)(void *arg, err_t err);
189 #endif /* LWIP_CALLBACK_API */
193 /* Figure out on which TCP PCB list we are, and remove us. If we
194 are in an active state, call the receive function associated with
195 the PCB with a NULL argument, and send an RST to the remote end. */
196 if (pcb->state == TIME_WAIT) {
197 tcp_pcb_remove(&tcp_tw_pcbs, pcb);
198 memp_free(MEMP_TCP_PCB, pcb);
200 seqno = pcb->snd_nxt;
201 ackno = pcb->rcv_nxt;
202 ip_addr_set(&local_ip, &(pcb->local_ip));
203 ip_addr_set(&remote_ip, &(pcb->remote_ip));
204 local_port = pcb->local_port;
205 remote_port = pcb->remote_port;
206 #if LWIP_CALLBACK_API
208 #endif /* LWIP_CALLBACK_API */
209 errf_arg = pcb->callback_arg;
210 tcp_pcb_remove(&tcp_active_pcbs, pcb);
211 if (pcb->unacked != NULL) {
212 tcp_segs_free(pcb->unacked);
214 if (pcb->unsent != NULL) {
215 tcp_segs_free(pcb->unsent);
218 if (pcb->ooseq != NULL) {
219 tcp_segs_free(pcb->ooseq);
221 #endif /* TCP_QUEUE_OOSEQ */
222 memp_free(MEMP_TCP_PCB, pcb);
223 TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT);
224 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abort: sending RST\n"));
225 tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port);
230 * Binds the connection to a local portnumber and IP address. If the
231 * IP address is not given (i.e., ipaddr == NULL), the IP address of
232 * the outgoing network interface is used instead.
237 tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
239 struct tcp_pcb *cpcb;
242 port = tcp_new_port();
244 /* Check if the address already is in use. */
245 for(cpcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs;
246 cpcb != NULL; cpcb = cpcb->next) {
247 if (cpcb->local_port == port) {
248 if (ip_addr_isany(&(cpcb->local_ip)) ||
249 ip_addr_isany(ipaddr) ||
250 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
255 for(cpcb = tcp_active_pcbs;
256 cpcb != NULL; cpcb = cpcb->next) {
257 if (cpcb->local_port == port) {
258 if (ip_addr_isany(&(cpcb->local_ip)) ||
259 ip_addr_isany(ipaddr) ||
260 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) {
266 if (!ip_addr_isany(ipaddr)) {
267 pcb->local_ip = *ipaddr;
269 pcb->local_port = port;
270 LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
273 #if LWIP_CALLBACK_API
275 tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
283 #endif /* LWIP_CALLBACK_API */
286 * Set the state of the connection to be LISTEN, which means that it
287 * is able to accept incoming connections. The protocol control block
288 * is reallocated in order to consume less memory. Setting the
289 * connection to LISTEN is an irreversible process.
293 tcp_listen(struct tcp_pcb *pcb)
295 struct tcp_pcb_listen *lpcb;
297 /* already listening? */
298 if (pcb->state == LISTEN) {
301 lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
305 lpcb->callback_arg = pcb->callback_arg;
306 lpcb->local_port = pcb->local_port;
307 lpcb->state = LISTEN;
308 lpcb->so_options = pcb->so_options;
309 lpcb->so_options |= SOF_ACCEPTCONN;
310 lpcb->ttl = pcb->ttl;
311 lpcb->tos = pcb->tos;
312 ip_addr_set(&lpcb->local_ip, &pcb->local_ip);
313 memp_free(MEMP_TCP_PCB, pcb);
314 #if LWIP_CALLBACK_API
315 lpcb->accept = tcp_accept_null;
316 #endif /* LWIP_CALLBACK_API */
317 TCP_REG(&tcp_listen_pcbs.listen_pcbs, lpcb);
318 return (struct tcp_pcb *)lpcb;
322 * This function should be called by the application when it has
323 * processed the data. The purpose is to advertise a larger window
324 * when the data has been processed.
328 tcp_recved(struct tcp_pcb *pcb, u16_t len)
330 if ((u32_t)pcb->rcv_wnd + len > TCP_WND) {
331 pcb->rcv_wnd = TCP_WND;
335 if (!(pcb->flags & TF_ACK_DELAY) &&
336 !(pcb->flags & TF_ACK_NOW)) {
338 * We send an ACK here (if one is not already pending, hence
339 * the above tests) as tcp_recved() implies that the application
340 * has processed some data, and so we can open the receiver's
341 * window to allow more to be transmitted. This could result in
342 * two ACKs being sent for each received packet in some limited cases
343 * (where the application is only receiving data, and is slow to
344 * process it) but it is necessary to guarantee that the sender can
345 * continue to transmit.
349 else if (pcb->flags & TF_ACK_DELAY && pcb->rcv_wnd >= TCP_WND/2) {
350 /* If we can send a window update such that there is a full
351 * segment available in the window, do so now. This is sort of
352 * nagle-like in its goals, and tries to hit a compromise between
353 * sending acks each time the window is updated, and only sending
354 * window updates when a timer expires. The "threshold" used
355 * above (currently TCP_WND/2) can be tuned to be more or less
360 LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n",
361 len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd));
365 * A nastly hack featuring 'goto' statements that allocates a
366 * new TCP local port.
372 #ifndef TCP_LOCAL_PORT_RANGE_START
373 #define TCP_LOCAL_PORT_RANGE_START 4096
374 #define TCP_LOCAL_PORT_RANGE_END 0x7fff
376 static u16_t port = TCP_LOCAL_PORT_RANGE_START;
379 if (++port > TCP_LOCAL_PORT_RANGE_END) {
380 port = TCP_LOCAL_PORT_RANGE_START;
383 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
384 if (pcb->local_port == port) {
388 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
389 if (pcb->local_port == port) {
393 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
394 if (pcb->local_port == port) {
402 * Connects to another host. The function given as the "connected"
403 * argument will be called when the connection has been established.
407 tcp_connect(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port,
408 err_t (* connected)(void *arg, struct tcp_pcb *tpcb, err_t err))
414 LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
415 if (ipaddr != NULL) {
416 pcb->remote_ip = *ipaddr;
420 pcb->remote_port = port;
421 if (pcb->local_port == 0) {
422 pcb->local_port = tcp_new_port();
424 iss = tcp_next_iss();
427 pcb->lastack = iss - 1;
428 pcb->snd_lbb = iss - 1;
429 pcb->rcv_wnd = TCP_WND;
430 pcb->snd_wnd = TCP_WND;
433 pcb->ssthresh = pcb->mss * 10;
434 pcb->state = SYN_SENT;
435 #if LWIP_CALLBACK_API
436 pcb->connected = connected;
437 #endif /* LWIP_CALLBACK_API */
438 TCP_REG(&tcp_active_pcbs, pcb);
440 /* Build an MSS option */
441 optdata = htonl(((u32_t)2 << 24) |
443 (((u32_t)pcb->mss / 256) << 8) |
446 ret = tcp_enqueue(pcb, NULL, 0, TCP_SYN, 0, (u8_t *)&optdata, 4);
454 * Called every 500 ms and implements the retransmission timer and the timer that
455 * removes PCBs that have been in TIME-WAIT for enough time. It also increments
456 * various timers such as the inactivity timer in each PCB.
461 struct tcp_pcb *pcb, *pcb2, *prev;
463 u8_t pcb_remove; /* flag if a PCB should be removed */
470 /* Steps through all of the active PCBs. */
472 pcb = tcp_active_pcbs;
474 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
476 while (pcb != NULL) {
477 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n"));
478 LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED);
479 LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN);
480 LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT);
484 if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
486 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
488 else if (pcb->nrtx == TCP_MAXRTX) {
490 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
493 if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
495 /* Time for a retransmission. */
496 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"U16_F" pcb->rto %"U16_F"\n",
497 pcb->rtime, pcb->rto));
499 /* Double retransmission time-out unless we are trying to
500 * connect to somebody (i.e., we are in SYN_SENT). */
501 if (pcb->state != SYN_SENT) {
502 pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx];
504 /* Reduce congestion window and ssthresh. */
505 eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd);
506 pcb->ssthresh = eff_wnd >> 1;
507 if (pcb->ssthresh < pcb->mss) {
508 pcb->ssthresh = pcb->mss * 2;
510 pcb->cwnd = pcb->mss;
511 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F" ssthresh %"U16_F"\n",
512 pcb->cwnd, pcb->ssthresh));
514 /* The following needs to be called AFTER cwnd is set to one mss - STJ */
518 /* Check if this PCB has stayed too long in FIN-WAIT-2 */
519 if (pcb->state == FIN_WAIT_2) {
520 if ((u32_t)(tcp_ticks - pcb->tmr) >
521 TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) {
523 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
527 /* Check if KEEPALIVE should be sent */
528 if((pcb->so_options & SOF_KEEPALIVE) && ((pcb->state == ESTABLISHED) || (pcb->state == CLOSE_WAIT))) {
529 if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keepalive + TCP_MAXIDLE) / TCP_SLOW_INTERVAL) {
530 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n",
531 ip4_addr1(&pcb->remote_ip), ip4_addr2(&pcb->remote_ip),
532 ip4_addr3(&pcb->remote_ip), ip4_addr4(&pcb->remote_ip)));
536 else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keepalive + pcb->keep_cnt * TCP_KEEPINTVL) / TCP_SLOW_INTERVAL) {
542 /* If this PCB has queued out of sequence data, but has been
543 inactive for too long, will drop the data (it will eventually
544 be retransmitted). */
546 if (pcb->ooseq != NULL &&
547 (u32_t)tcp_ticks - pcb->tmr >=
548 pcb->rto * TCP_OOSEQ_TIMEOUT) {
549 tcp_segs_free(pcb->ooseq);
551 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
553 #endif /* TCP_QUEUE_OOSEQ */
555 /* Check if this PCB has stayed too long in SYN-RCVD */
556 if (pcb->state == SYN_RCVD) {
557 if ((u32_t)(tcp_ticks - pcb->tmr) >
558 TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
560 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
564 /* Check if this PCB has stayed too long in LAST-ACK */
565 if (pcb->state == LAST_ACK) {
566 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
568 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
572 /* If the PCB should be removed, do it. */
575 /* Remove PCB from tcp_active_pcbs list. */
577 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
578 prev->next = pcb->next;
580 /* This PCB was the first. */
581 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb);
582 tcp_active_pcbs = pcb->next;
585 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
588 memp_free(MEMP_TCP_PCB, pcb);
592 /* We check if we should poll the connection. */
594 if (pcb->polltmr >= pcb->pollinterval) {
596 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
597 TCP_EVENT_POLL(pcb, err);
609 /* Steps through all of the TIME-WAIT PCBs. */
612 while (pcb != NULL) {
613 LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
616 /* Check if this PCB has stayed long enough in TIME-WAIT */
617 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) {
623 /* If the PCB should be removed, do it. */
626 /* Remove PCB from tcp_tw_pcbs list. */
628 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
629 prev->next = pcb->next;
631 /* This PCB was the first. */
632 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb);
633 tcp_tw_pcbs = pcb->next;
636 memp_free(MEMP_TCP_PCB, pcb);
646 * Is called every TCP_FAST_INTERVAL (250 ms) and sends delayed ACKs.
653 /* send delayed ACKs */
654 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
655 if (pcb->flags & TF_ACK_DELAY) {
656 LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n"));
658 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
664 * Deallocates a list of TCP segments (tcp_seg structures).
668 tcp_segs_free(struct tcp_seg *seg)
671 struct tcp_seg *next;
672 while (seg != NULL) {
674 count += tcp_seg_free(seg);
681 * Frees a TCP segment.
685 tcp_seg_free(struct tcp_seg *seg)
690 if (seg->p != NULL) {
691 count = pbuf_free(seg->p);
694 #endif /* TCP_DEBUG */
696 memp_free(MEMP_TCP_SEG, seg);
702 * Sets the priority of a connection.
706 tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
713 * Returns a copy of the given TCP segment.
717 tcp_seg_copy(struct tcp_seg *seg)
719 struct tcp_seg *cseg;
721 cseg = memp_malloc(MEMP_TCP_SEG);
725 memcpy((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg));
731 #if LWIP_CALLBACK_API
733 tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
738 } else if (err == ERR_OK) {
739 return tcp_close(pcb);
743 #endif /* LWIP_CALLBACK_API */
746 tcp_kill_prio(u8_t prio)
748 struct tcp_pcb *pcb, *inactive;
753 mprio = TCP_PRIO_MAX;
755 /* We kill the oldest active connection that has lower priority than
759 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
760 if (pcb->prio <= prio &&
761 pcb->prio <= mprio &&
762 (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
763 inactivity = tcp_ticks - pcb->tmr;
768 if (inactive != NULL) {
769 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
770 (void *)inactive, inactivity));
777 tcp_kill_timewait(void)
779 struct tcp_pcb *pcb, *inactive;
784 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
785 if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) {
786 inactivity = tcp_ticks - pcb->tmr;
790 if (inactive != NULL) {
791 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n",
792 (void *)inactive, inactivity));
805 pcb = memp_malloc(MEMP_TCP_PCB);
807 /* Try killing oldest connection in TIME-WAIT. */
808 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
810 pcb = memp_malloc(MEMP_TCP_PCB);
813 pcb = memp_malloc(MEMP_TCP_PCB);
817 memset(pcb, 0, sizeof(struct tcp_pcb));
818 pcb->prio = TCP_PRIO_NORMAL;
819 pcb->snd_buf = TCP_SND_BUF;
820 pcb->snd_queuelen = 0;
821 pcb->rcv_wnd = TCP_WND;
825 pcb->rto = 3000 / TCP_SLOW_INTERVAL;
827 pcb->sv = 3000 / TCP_SLOW_INTERVAL;
830 iss = tcp_next_iss();
836 pcb->tmr = tcp_ticks;
840 #if LWIP_CALLBACK_API
841 pcb->recv = tcp_recv_null;
842 #endif /* LWIP_CALLBACK_API */
844 /* Init KEEPALIVE timer */
845 pcb->keepalive = TCP_KEEPDEFAULT;
852 * Creates a new TCP protocol control block but doesn't place it on
853 * any of the TCP PCB lists.
855 * @internal: Maybe there should be a idle TCP PCB list where these
856 * PCBs are put on. We can then implement port reservation using
857 * tcp_bind(). Currently, we lack this (BSD socket type of) feature.
863 return tcp_alloc(TCP_PRIO_NORMAL);
869 * Used to specify the argument that should be passed callback
875 tcp_arg(struct tcp_pcb *pcb, void *arg)
877 pcb->callback_arg = arg;
879 #if LWIP_CALLBACK_API
882 * Used to specify the function that should be called when a TCP
883 * connection receives data.
887 tcp_recv(struct tcp_pcb *pcb,
888 err_t (* recv)(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err))
894 * Used to specify the function that should be called when TCP data
895 * has been successfully delivered to the remote host.
900 tcp_sent(struct tcp_pcb *pcb,
901 err_t (* sent)(void *arg, struct tcp_pcb *tpcb, u16_t len))
907 * Used to specify the function that should be called when a fatal error
908 * has occured on the connection.
912 tcp_err(struct tcp_pcb *pcb,
913 void (* errf)(void *arg, err_t err))
919 * Used for specifying the function that should be called when a
920 * LISTENing connection has been connected to another host.
924 tcp_accept(struct tcp_pcb *pcb,
925 err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err))
927 ((struct tcp_pcb_listen *)pcb)->accept = accept;
929 #endif /* LWIP_CALLBACK_API */
933 * Used to specify the function that should be called periodically
934 * from TCP. The interval is specified in terms of the TCP coarse
935 * timer interval, which is called twice a second.
939 tcp_poll(struct tcp_pcb *pcb,
940 err_t (* poll)(void *arg, struct tcp_pcb *tpcb), u8_t interval)
942 #if LWIP_CALLBACK_API
944 #endif /* LWIP_CALLBACK_API */
945 pcb->pollinterval = interval;
949 * Purges a TCP PCB. Removes any buffered data and frees the buffer memory.
953 tcp_pcb_purge(struct tcp_pcb *pcb)
955 if (pcb->state != CLOSED &&
956 pcb->state != TIME_WAIT &&
957 pcb->state != LISTEN) {
959 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
961 if (pcb->unsent != NULL) {
962 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
964 if (pcb->unacked != NULL) {
965 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
967 #if TCP_QUEUE_OOSEQ /* LW */
968 if (pcb->ooseq != NULL) {
969 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
972 tcp_segs_free(pcb->ooseq);
974 #endif /* TCP_QUEUE_OOSEQ */
975 tcp_segs_free(pcb->unsent);
976 tcp_segs_free(pcb->unacked);
977 pcb->unacked = pcb->unsent = NULL;
982 * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
986 tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
988 TCP_RMV(pcblist, pcb);
992 /* if there is an outstanding delayed ACKs, send it */
993 if (pcb->state != TIME_WAIT &&
994 pcb->state != LISTEN &&
995 pcb->flags & TF_ACK_DELAY) {
996 pcb->flags |= TF_ACK_NOW;
1001 LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
1005 * Calculates a new initial sequence number for new connections.
1011 static u32_t iss = 6510;
1013 iss += tcp_ticks; /* XXX */
1017 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
1019 tcp_debug_print(struct tcp_hdr *tcphdr)
1021 LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n"));
1022 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1023 LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n",
1024 ntohs(tcphdr->src), ntohs(tcphdr->dest)));
1025 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1026 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n",
1027 ntohl(tcphdr->seqno)));
1028 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1029 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n",
1030 ntohl(tcphdr->ackno)));
1031 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1032 LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (",
1033 TCPH_HDRLEN(tcphdr),
1034 TCPH_FLAGS(tcphdr) >> 5 & 1,
1035 TCPH_FLAGS(tcphdr) >> 4 & 1,
1036 TCPH_FLAGS(tcphdr) >> 3 & 1,
1037 TCPH_FLAGS(tcphdr) >> 2 & 1,
1038 TCPH_FLAGS(tcphdr) >> 1 & 1,
1039 TCPH_FLAGS(tcphdr) & 1,
1040 ntohs(tcphdr->wnd)));
1041 tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
1042 LWIP_DEBUGF(TCP_DEBUG, ("), win)\n"));
1043 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1044 LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n",
1045 ntohs(tcphdr->chksum), ntohs(tcphdr->urgp)));
1046 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
1050 tcp_debug_print_state(enum tcp_state s)
1052 LWIP_DEBUGF(TCP_DEBUG, ("State: "));
1055 LWIP_DEBUGF(TCP_DEBUG, ("CLOSED\n"));
1058 LWIP_DEBUGF(TCP_DEBUG, ("LISTEN\n"));
1061 LWIP_DEBUGF(TCP_DEBUG, ("SYN_SENT\n"));
1064 LWIP_DEBUGF(TCP_DEBUG, ("SYN_RCVD\n"));
1067 LWIP_DEBUGF(TCP_DEBUG, ("ESTABLISHED\n"));
1070 LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_1\n"));
1073 LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_2\n"));
1076 LWIP_DEBUGF(TCP_DEBUG, ("CLOSE_WAIT\n"));
1079 LWIP_DEBUGF(TCP_DEBUG, ("CLOSING\n"));
1082 LWIP_DEBUGF(TCP_DEBUG, ("LAST_ACK\n"));
1085 LWIP_DEBUGF(TCP_DEBUG, ("TIME_WAIT\n"));
1091 tcp_debug_print_flags(u8_t flags)
1093 if (flags & TCP_FIN) {
1094 LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
1096 if (flags & TCP_SYN) {
1097 LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
1099 if (flags & TCP_RST) {
1100 LWIP_DEBUGF(TCP_DEBUG, ("RST "));
1102 if (flags & TCP_PSH) {
1103 LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
1105 if (flags & TCP_ACK) {
1106 LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
1108 if (flags & TCP_URG) {
1109 LWIP_DEBUGF(TCP_DEBUG, ("URG "));
1111 if (flags & TCP_ECE) {
1112 LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
1114 if (flags & TCP_CWR) {
1115 LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
1120 tcp_debug_print_pcbs(void)
1122 struct tcp_pcb *pcb;
1123 LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n"));
1124 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1125 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1126 pcb->local_port, pcb->remote_port,
1127 pcb->snd_nxt, pcb->rcv_nxt));
1128 tcp_debug_print_state(pcb->state);
1130 LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n"));
1131 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
1132 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1133 pcb->local_port, pcb->remote_port,
1134 pcb->snd_nxt, pcb->rcv_nxt));
1135 tcp_debug_print_state(pcb->state);
1137 LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n"));
1138 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1139 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ",
1140 pcb->local_port, pcb->remote_port,
1141 pcb->snd_nxt, pcb->rcv_nxt));
1142 tcp_debug_print_state(pcb->state);
1149 struct tcp_pcb *pcb;
1150 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
1151 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED);
1152 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN);
1153 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
1155 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
1156 LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
1160 #endif /* TCP_DEBUG */
1161 #endif /* LWIP_TCP */