lwip/core/tcp.c

   1 /**
   2  * @file
   3  *
   4  * Transmission Control Protocol for IP
   5  *
   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.
   9  *
  10  */
  11
  12 /*
  13  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
  14  * All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without modification,
  17  * are permitted provided that the following conditions are met:
  18  *
  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.
  26  *
  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
  36  * OF SUCH DAMAGE.
  37  *
  38  * This file is part of the lwIP TCP/IP stack.
  39  *
  40  * Author: Adam Dunkels <adam@sics.se>
  41  *
  42  */
  43
  44 #include <string.h>
  45
  46 #include "lwip/opt.h"
  47 #include "lwip/def.h"
  48 #include "lwip/mem.h"
  49 #include "lwip/memp.h"
  50
  51 #include "lwip/tcp.h"
  52 #if LWIP_TCP
  53
  54 /* Incremented every coarse grained timer shot
  55    (typically every 500 ms, determined by TCP_COARSE_TIMEOUT). */
  56 u32_t tcp_ticks;
  57 const u8_t tcp_backoff[13] =
  58     { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
  59
  60 /* The TCP PCB lists. */
  61
  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;
  69
  70 struct tcp_pcb *tcp_tmp_pcb;
  71
  72 static u8_t tcp_timer;
  73 static u16_t tcp_new_port(void);
  74
  75 /**
  76  * Initializes the TCP layer.
  77  */
  78 void
  79 tcp_init(void)
  80 {
  81   /* Clear globals. */
  82   tcp_listen_pcbs.listen_pcbs = NULL;
  83   tcp_active_pcbs = NULL;
  84   tcp_tw_pcbs = NULL;
  85   tcp_tmp_pcb = NULL;
  86
  87   /* initialize timer */
  88   tcp_ticks = 0;
  89   tcp_timer = 0;
  90
  91 }
  92
  93 /**
  94  * Called periodically to dispatch TCP timers.
  95  *
  96  */
  97 void
  98 tcp_tmr(void)
  99 {
 100   /* Call tcp_fasttmr() every 250 ms */
 101   tcp_fasttmr();
 102
 103   if (++tcp_timer & 1) {
 104     /* Call tcp_tmr() every 500 ms, i.e., every other timer
 105        tcp_tmr() is called. */
 106     tcp_slowtmr();
 107   }
 108 }
 109
 110 /**
 111  * Closes the connection held by the PCB.
 112  *
 113  */
 114 err_t
 115 tcp_close(struct tcp_pcb *pcb)
 116 {
 117   err_t err;
 118
 119 #if TCP_DEBUG
 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) {
 125   case CLOSED:
 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. */
 133     err = ERR_OK;
 134     memp_free(MEMP_TCP_PCB, pcb);
 135     pcb = NULL;
 136     break;
 137   case LISTEN:
 138     err = ERR_OK;
 139     tcp_pcb_remove((struct tcp_pcb **)&tcp_listen_pcbs.pcbs, pcb);
 140     memp_free(MEMP_TCP_PCB_LISTEN, pcb);
 141     pcb = NULL;
 142     break;
 143   case SYN_SENT:
 144     err = ERR_OK;
 145     tcp_pcb_remove(&tcp_active_pcbs, pcb);
 146     memp_free(MEMP_TCP_PCB, pcb);
 147     pcb = NULL;
 148     break;
 149   case SYN_RCVD:
 150   case ESTABLISHED:
 151     err = tcp_send_ctrl(pcb, TCP_FIN);
 152     if (err == ERR_OK) {
 153       pcb->state = FIN_WAIT_1;
 154     }
 155     break;
 156   case CLOSE_WAIT:
 157     err = tcp_send_ctrl(pcb, TCP_FIN);
 158     if (err == ERR_OK) {
 159       pcb->state = LAST_ACK;
 160     }
 161     break;
 162   default:
 163     /* Has already been closed, do nothing. */
 164     err = ERR_OK;
 165     pcb = NULL;
 166     break;
 167   }
 168
 169   if (pcb != NULL && err == ERR_OK) {
 170     err = tcp_output(pcb);
 171   }
 172   return err;
 173 }
 174
 175 /**
 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.
 179  *
 180  */
 181 void
 182 tcp_abort(struct tcp_pcb *pcb)
 183 {
 184   u32_t seqno, ackno;
 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 */
 190   void *errf_arg;
 191
 192
 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);
 199   } else {
 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
 207     errf = pcb->errf;
 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);
 213     }
 214     if (pcb->unsent != NULL) {
 215       tcp_segs_free(pcb->unsent);
 216     }
 217 #if TCP_QUEUE_OOSEQ
 218     if (pcb->ooseq != NULL) {
 219       tcp_segs_free(pcb->ooseq);
 220     }
 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);
 226   }
 227 }
 228
 229 /**
 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.
 233  *
 234  */
 235
 236 err_t
 237 tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
 238 {
 239   struct tcp_pcb *cpcb;
 240
 241   if (port == 0) {
 242     port = tcp_new_port();
 243   }
 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)) {
 251           return ERR_USE;
 252       }
 253     }
 254   }
 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)) {
 261   return ERR_USE;
 262       }
 263     }
 264   }
 265
 266   if (!ip_addr_isany(ipaddr)) {
 267     pcb->local_ip = *ipaddr;
 268   }
 269   pcb->local_port = port;
 270   LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port));
 271   return ERR_OK;
 272 }
 273 #if LWIP_CALLBACK_API
 274 static err_t
 275 tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err)
 276 {
 277   (void)arg;
 278   (void)pcb;
 279   (void)err;
 280
 281   return ERR_ABRT;
 282 }
 283 #endif /* LWIP_CALLBACK_API */
 284
 285 /**
 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.
 290  *
 291  */
 292 struct tcp_pcb *
 293 tcp_listen(struct tcp_pcb *pcb)
 294 {
 295   struct tcp_pcb_listen *lpcb;
 296
 297   /* already listening? */
 298   if (pcb->state == LISTEN) {
 299     return pcb;
 300   }
 301   lpcb = memp_malloc(MEMP_TCP_PCB_LISTEN);
 302   if (lpcb == NULL) {
 303     return NULL;
 304   }
 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;
 319 }
 320
 321 /**
 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.
 325  *
 326  */
 327 void
 328 tcp_recved(struct tcp_pcb *pcb, u16_t len)
 329 {
 330   if ((u32_t)pcb->rcv_wnd + len > TCP_WND) {
 331     pcb->rcv_wnd = TCP_WND;
 332   } else {
 333     pcb->rcv_wnd += len;
 334   }
 335   if (!(pcb->flags & TF_ACK_DELAY) &&
 336      !(pcb->flags & TF_ACK_NOW)) {
 337     /*
 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.
 346      */
 347     tcp_ack(pcb);
 348   }
 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
 356      * aggressive  */
 357     tcp_ack_now(pcb);
 358   }
 359
 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));
 362 }
 363
 364 /**
 365  * A nastly hack featuring 'goto' statements that allocates a
 366  * new TCP local port.
 367  */
 368 static u16_t
 369 tcp_new_port(void)
 370 {
 371   struct tcp_pcb *pcb;
 372 #ifndef TCP_LOCAL_PORT_RANGE_START
 373 #define TCP_LOCAL_PORT_RANGE_START 4096
 374 #define TCP_LOCAL_PORT_RANGE_END   0x7fff
 375 #endif
 376   static u16_t port = TCP_LOCAL_PORT_RANGE_START;
 377
 378  again:
 379   if (++port > TCP_LOCAL_PORT_RANGE_END) {
 380     port = TCP_LOCAL_PORT_RANGE_START;
 381   }
 382
 383   for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
 384     if (pcb->local_port == port) {
 385       goto again;
 386     }
 387   }
 388   for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
 389     if (pcb->local_port == port) {
 390       goto again;
 391     }
 392   }
 393   for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) {
 394     if (pcb->local_port == port) {
 395       goto again;
 396     }
 397   }
 398   return port;
 399 }
 400
 401 /**
 402  * Connects to another host. The function given as the "connected"
 403  * argument will be called when the connection has been established.
 404  *
 405  */
 406 err_t
 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))
 409 {
 410   u32_t optdata;
 411   err_t ret;
 412   u32_t iss;
 413
 414   LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port));
 415   if (ipaddr != NULL) {
 416     pcb->remote_ip = *ipaddr;
 417   } else {
 418     return ERR_VAL;
 419   }
 420   pcb->remote_port = port;
 421   if (pcb->local_port == 0) {
 422     pcb->local_port = tcp_new_port();
 423   }
 424   iss = tcp_next_iss();
 425   pcb->rcv_nxt = 0;
 426   pcb->snd_nxt = iss;
 427   pcb->lastack = iss - 1;
 428   pcb->snd_lbb = iss - 1;
 429   pcb->rcv_wnd = TCP_WND;
 430   pcb->snd_wnd = TCP_WND;
 431   pcb->mss = TCP_MSS;
 432   pcb->cwnd = 1;
 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);
 439
 440   /* Build an MSS option */
 441   optdata = htonl(((u32_t)2 << 24) |
 442       ((u32_t)4 << 16) |
 443       (((u32_t)pcb->mss / 256) << 8) |
 444       (pcb->mss & 255));
 445
 446   ret = tcp_enqueue(pcb, NULL, 0, TCP_SYN, 0, (u8_t *)&optdata, 4);
 447   if (ret == ERR_OK) {
 448     tcp_output(pcb);
 449   }
 450   return ret;
 451 }
 452
 453 /**
 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.
 457  */
 458 void
 459 tcp_slowtmr(void)
 460 {
 461   struct tcp_pcb *pcb, *pcb2, *prev;
 462   u32_t eff_wnd;
 463   u8_t pcb_remove;      /* flag if a PCB should be removed */
 464   err_t err;
 465
 466   err = ERR_OK;
 467
 468   ++tcp_ticks;
 469
 470   /* Steps through all of the active PCBs. */
 471   prev = NULL;
 472   pcb = tcp_active_pcbs;
 473   if (pcb == NULL) {
 474     LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n"));
 475   }
 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);
 481
 482     pcb_remove = 0;
 483
 484     if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) {
 485       ++pcb_remove;
 486       LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n"));
 487     }
 488     else if (pcb->nrtx == TCP_MAXRTX) {
 489       ++pcb_remove;
 490       LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n"));
 491     } else {
 492       ++pcb->rtime;
 493       if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) {
 494
 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));
 498
 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];
 503         }
 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;
 509         }
 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));
 513
 514         /* The following needs to be called AFTER cwnd is set to one mss - STJ */
 515         tcp_rexmit_rto(pcb);
 516      }
 517     }
 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) {
 522         ++pcb_remove;
 523         LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n"));
 524       }
 525     }
 526
 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)));
 533
 534          tcp_abort(pcb);
 535       }
 536       else if((u32_t)(tcp_ticks - pcb->tmr) > (pcb->keepalive + pcb->keep_cnt * TCP_KEEPINTVL) / TCP_SLOW_INTERVAL) {
 537          tcp_keepalive(pcb);
 538          pcb->keep_cnt++;
 539       }
 540    }
 541
 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). */
 545 #if TCP_QUEUE_OOSEQ
 546     if (pcb->ooseq != NULL &&
 547        (u32_t)tcp_ticks - pcb->tmr >=
 548        pcb->rto * TCP_OOSEQ_TIMEOUT) {
 549       tcp_segs_free(pcb->ooseq);
 550       pcb->ooseq = NULL;
 551       LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n"));
 552     }
 553 #endif /* TCP_QUEUE_OOSEQ */
 554
 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) {
 559         ++pcb_remove;
 560         LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n"));
 561       }
 562     }
 563
 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) {
 567         ++pcb_remove;
 568         LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n"));
 569       }
 570     }
 571
 572     /* If the PCB should be removed, do it. */
 573     if (pcb_remove) {
 574       tcp_pcb_purge(pcb);
 575       /* Remove PCB from tcp_active_pcbs list. */
 576       if (prev != NULL) {
 577   LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs);
 578         prev->next = pcb->next;
 579       } else {
 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;
 583       }
 584
 585       TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT);
 586
 587       pcb2 = pcb->next;
 588       memp_free(MEMP_TCP_PCB, pcb);
 589       pcb = pcb2;
 590     } else {
 591
 592       /* We check if we should poll the connection. */
 593       ++pcb->polltmr;
 594       if (pcb->polltmr >= pcb->pollinterval) {
 595         pcb->polltmr = 0;
 596         LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n"));
 597         TCP_EVENT_POLL(pcb, err);
 598         if (err == ERR_OK) {
 599           tcp_output(pcb);
 600         }
 601       }
 602
 603       prev = pcb;
 604       pcb = pcb->next;
 605     }
 606   }
 607
 608
 609   /* Steps through all of the TIME-WAIT PCBs. */
 610   prev = NULL;
 611   pcb = tcp_tw_pcbs;
 612   while (pcb != NULL) {
 613     LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
 614     pcb_remove = 0;
 615
 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) {
 618       ++pcb_remove;
 619     }
 620
 621
 622
 623     /* If the PCB should be removed, do it. */
 624     if (pcb_remove) {
 625       tcp_pcb_purge(pcb);
 626       /* Remove PCB from tcp_tw_pcbs list. */
 627       if (prev != NULL) {
 628   LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs);
 629         prev->next = pcb->next;
 630       } else {
 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;
 634       }
 635       pcb2 = pcb->next;
 636       memp_free(MEMP_TCP_PCB, pcb);
 637       pcb = pcb2;
 638     } else {
 639       prev = pcb;
 640       pcb = pcb->next;
 641     }
 642   }
 643 }
 644
 645 /**
 646  * Is called every TCP_FAST_INTERVAL (250 ms) and sends delayed ACKs.
 647  */
 648 void
 649 tcp_fasttmr(void)
 650 {
 651   struct tcp_pcb *pcb;
 652
 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"));
 657       tcp_ack_now(pcb);
 658       pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW);
 659     }
 660   }
 661 }
 662
 663 /**
 664  * Deallocates a list of TCP segments (tcp_seg structures).
 665  *
 666  */
 667 u8_t
 668 tcp_segs_free(struct tcp_seg *seg)
 669 {
 670   u8_t count = 0;
 671   struct tcp_seg *next;
 672   while (seg != NULL) {
 673     next = seg->next;
 674     count += tcp_seg_free(seg);
 675     seg = next;
 676   }
 677   return count;
 678 }
 679
 680 /**
 681  * Frees a TCP segment.
 682  *
 683  */
 684 u8_t
 685 tcp_seg_free(struct tcp_seg *seg)
 686 {
 687   u8_t count = 0;
 688
 689   if (seg != NULL) {
 690     if (seg->p != NULL) {
 691       count = pbuf_free(seg->p);
 692 #if TCP_DEBUG
 693       seg->p = NULL;
 694 #endif /* TCP_DEBUG */
 695     }
 696     memp_free(MEMP_TCP_SEG, seg);
 697   }
 698   return count;
 699 }
 700
 701 /**
 702  * Sets the priority of a connection.
 703  *
 704  */
 705 void
 706 tcp_setprio(struct tcp_pcb *pcb, u8_t prio)
 707 {
 708   pcb->prio = prio;
 709 }
 710 #if TCP_QUEUE_OOSEQ
 711
 712 /**
 713  * Returns a copy of the given TCP segment.
 714  *
 715  */
 716 struct tcp_seg *
 717 tcp_seg_copy(struct tcp_seg *seg)
 718 {
 719   struct tcp_seg *cseg;
 720
 721   cseg = memp_malloc(MEMP_TCP_SEG);
 722   if (cseg == NULL) {
 723     return NULL;
 724   }
 725   memcpy((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg));
 726   pbuf_ref(cseg->p);
 727   return cseg;
 728 }
 729 #endif
 730
 731 #if LWIP_CALLBACK_API
 732 static err_t
 733 tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
 734 {
 735   arg = arg;
 736   if (p != NULL) {
 737     pbuf_free(p);
 738   } else if (err == ERR_OK) {
 739     return tcp_close(pcb);
 740   }
 741   return ERR_OK;
 742 }
 743 #endif /* LWIP_CALLBACK_API */
 744
 745 static void
 746 tcp_kill_prio(u8_t prio)
 747 {
 748   struct tcp_pcb *pcb, *inactive;
 749   u32_t inactivity;
 750   u8_t mprio;
 751
 752
 753   mprio = TCP_PRIO_MAX;
 754
 755   /* We kill the oldest active connection that has lower priority than
 756      prio. */
 757   inactivity = 0;
 758   inactive = NULL;
 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;
 764       inactive = pcb;
 765       mprio = pcb->prio;
 766     }
 767   }
 768   if (inactive != NULL) {
 769     LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n",
 770            (void *)inactive, inactivity));
 771     tcp_abort(inactive);
 772   }
 773 }
 774
 775
 776 static void
 777 tcp_kill_timewait(void)
 778 {
 779   struct tcp_pcb *pcb, *inactive;
 780   u32_t inactivity;
 781
 782   inactivity = 0;
 783   inactive = NULL;
 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;
 787       inactive = pcb;
 788     }
 789   }
 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));
 793     tcp_abort(inactive);
 794   }
 795 }
 796
 797
 798
 799 struct tcp_pcb *
 800 tcp_alloc(u8_t prio)
 801 {
 802   struct tcp_pcb *pcb;
 803   u32_t iss;
 804
 805   pcb = memp_malloc(MEMP_TCP_PCB);
 806   if (pcb == NULL) {
 807     /* Try killing oldest connection in TIME-WAIT. */
 808     LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n"));
 809     tcp_kill_timewait();
 810     pcb = memp_malloc(MEMP_TCP_PCB);
 811     if (pcb == NULL) {
 812       tcp_kill_prio(prio);
 813       pcb = memp_malloc(MEMP_TCP_PCB);
 814     }
 815   }
 816   if (pcb != NULL) {
 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;
 822     pcb->tos = 0;
 823     pcb->ttl = TCP_TTL;
 824     pcb->mss = TCP_MSS;
 825     pcb->rto = 3000 / TCP_SLOW_INTERVAL;
 826     pcb->sa = 0;
 827     pcb->sv = 3000 / TCP_SLOW_INTERVAL;
 828     pcb->rtime = 0;
 829     pcb->cwnd = 1;
 830     iss = tcp_next_iss();
 831     pcb->snd_wl2 = iss;
 832     pcb->snd_nxt = iss;
 833     pcb->snd_max = iss;
 834     pcb->lastack = iss;
 835     pcb->snd_lbb = iss;
 836     pcb->tmr = tcp_ticks;
 837
 838     pcb->polltmr = 0;
 839
 840 #if LWIP_CALLBACK_API
 841     pcb->recv = tcp_recv_null;
 842 #endif /* LWIP_CALLBACK_API */
 843
 844     /* Init KEEPALIVE timer */
 845     pcb->keepalive = TCP_KEEPDEFAULT;
 846     pcb->keep_cnt = 0;
 847   }
 848   return pcb;
 849 }
 850
 851 /**
 852  * Creates a new TCP protocol control block but doesn't place it on
 853  * any of the TCP PCB lists.
 854  *
 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.
 858  */
 859
 860 struct tcp_pcb *
 861 tcp_new(void)
 862 {
 863   return tcp_alloc(TCP_PRIO_NORMAL);
 864 }
 865
 866 /*
 867  * tcp_arg():
 868  *
 869  * Used to specify the argument that should be passed callback
 870  * functions.
 871  *
 872  */
 873
 874 void
 875 tcp_arg(struct tcp_pcb *pcb, void *arg)
 876 {
 877   pcb->callback_arg = arg;
 878 }
 879 #if LWIP_CALLBACK_API
 880
 881 /**
 882  * Used to specify the function that should be called when a TCP
 883  * connection receives data.
 884  *
 885  */
 886 void
 887 tcp_recv(struct tcp_pcb *pcb,
 888    err_t (* recv)(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err))
 889 {
 890   pcb->recv = recv;
 891 }
 892
 893 /**
 894  * Used to specify the function that should be called when TCP data
 895  * has been successfully delivered to the remote host.
 896  *
 897  */
 898
 899 void
 900 tcp_sent(struct tcp_pcb *pcb,
 901    err_t (* sent)(void *arg, struct tcp_pcb *tpcb, u16_t len))
 902 {
 903   pcb->sent = sent;
 904 }
 905
 906 /**
 907  * Used to specify the function that should be called when a fatal error
 908  * has occured on the connection.
 909  *
 910  */
 911 void
 912 tcp_err(struct tcp_pcb *pcb,
 913    void (* errf)(void *arg, err_t err))
 914 {
 915   pcb->errf = errf;
 916 }
 917
 918 /**
 919  * Used for specifying the function that should be called when a
 920  * LISTENing connection has been connected to another host.
 921  *
 922  */
 923 void
 924 tcp_accept(struct tcp_pcb *pcb,
 925      err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err))
 926 {
 927   ((struct tcp_pcb_listen *)pcb)->accept = accept;
 928 }
 929 #endif /* LWIP_CALLBACK_API */
 930
 931
 932 /**
 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.
 936  *
 937  */
 938 void
 939 tcp_poll(struct tcp_pcb *pcb,
 940    err_t (* poll)(void *arg, struct tcp_pcb *tpcb), u8_t interval)
 941 {
 942 #if LWIP_CALLBACK_API
 943   pcb->poll = poll;
 944 #endif /* LWIP_CALLBACK_API */
 945   pcb->pollinterval = interval;
 946 }
 947
 948 /**
 949  * Purges a TCP PCB. Removes any buffered data and frees the buffer memory.
 950  *
 951  */
 952 void
 953 tcp_pcb_purge(struct tcp_pcb *pcb)
 954 {
 955   if (pcb->state != CLOSED &&
 956      pcb->state != TIME_WAIT &&
 957      pcb->state != LISTEN) {
 958
 959     LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n"));
 960
 961     if (pcb->unsent != NULL) {
 962       LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n"));
 963     }
 964     if (pcb->unacked != NULL) {
 965       LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n"));
 966     }
 967 #if TCP_QUEUE_OOSEQ /* LW */
 968     if (pcb->ooseq != NULL) {
 969       LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n"));
 970     }
 971
 972     tcp_segs_free(pcb->ooseq);
 973     pcb->ooseq = NULL;
 974 #endif /* TCP_QUEUE_OOSEQ */
 975     tcp_segs_free(pcb->unsent);
 976     tcp_segs_free(pcb->unacked);
 977     pcb->unacked = pcb->unsent = NULL;
 978   }
 979 }
 980
 981 /**
 982  * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.
 983  *
 984  */
 985 void
 986 tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
 987 {
 988   TCP_RMV(pcblist, pcb);
 989
 990   tcp_pcb_purge(pcb);
 991
 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;
 997     tcp_output(pcb);
 998   }
 999   pcb->state = CLOSED;
1000
1001   LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane());
1002 }
1003
1004 /**
1005  * Calculates a new initial sequence number for new connections.
1006  *
1007  */
1008 u32_t
1009 tcp_next_iss(void)
1010 {
1011   static u32_t iss = 6510;
1012
1013   iss += tcp_ticks;       /* XXX */
1014   return iss;
1015 }
1016
1017 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
1018 void
1019 tcp_debug_print(struct tcp_hdr *tcphdr)
1020 {
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"));
1047 }
1048
1049 void
1050 tcp_debug_print_state(enum tcp_state s)
1051 {
1052   LWIP_DEBUGF(TCP_DEBUG, ("State: "));
1053   switch (s) {
1054   case CLOSED:
1055     LWIP_DEBUGF(TCP_DEBUG, ("CLOSED\n"));
1056     break;
1057  case LISTEN:
1058    LWIP_DEBUGF(TCP_DEBUG, ("LISTEN\n"));
1059    break;
1060   case SYN_SENT:
1061     LWIP_DEBUGF(TCP_DEBUG, ("SYN_SENT\n"));
1062     break;
1063   case SYN_RCVD:
1064     LWIP_DEBUGF(TCP_DEBUG, ("SYN_RCVD\n"));
1065     break;
1066   case ESTABLISHED:
1067     LWIP_DEBUGF(TCP_DEBUG, ("ESTABLISHED\n"));
1068     break;
1069   case FIN_WAIT_1:
1070     LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_1\n"));
1071     break;
1072   case FIN_WAIT_2:
1073     LWIP_DEBUGF(TCP_DEBUG, ("FIN_WAIT_2\n"));
1074     break;
1075   case CLOSE_WAIT:
1076     LWIP_DEBUGF(TCP_DEBUG, ("CLOSE_WAIT\n"));
1077     break;
1078   case CLOSING:
1079     LWIP_DEBUGF(TCP_DEBUG, ("CLOSING\n"));
1080     break;
1081   case LAST_ACK:
1082     LWIP_DEBUGF(TCP_DEBUG, ("LAST_ACK\n"));
1083     break;
1084   case TIME_WAIT:
1085     LWIP_DEBUGF(TCP_DEBUG, ("TIME_WAIT\n"));
1086    break;
1087   }
1088 }
1089
1090 void
1091 tcp_debug_print_flags(u8_t flags)
1092 {
1093   if (flags & TCP_FIN) {
1094     LWIP_DEBUGF(TCP_DEBUG, ("FIN "));
1095   }
1096   if (flags & TCP_SYN) {
1097     LWIP_DEBUGF(TCP_DEBUG, ("SYN "));
1098   }
1099   if (flags & TCP_RST) {
1100     LWIP_DEBUGF(TCP_DEBUG, ("RST "));
1101   }
1102   if (flags & TCP_PSH) {
1103     LWIP_DEBUGF(TCP_DEBUG, ("PSH "));
1104   }
1105   if (flags & TCP_ACK) {
1106     LWIP_DEBUGF(TCP_DEBUG, ("ACK "));
1107   }
1108   if (flags & TCP_URG) {
1109     LWIP_DEBUGF(TCP_DEBUG, ("URG "));
1110   }
1111   if (flags & TCP_ECE) {
1112     LWIP_DEBUGF(TCP_DEBUG, ("ECE "));
1113   }
1114   if (flags & TCP_CWR) {
1115     LWIP_DEBUGF(TCP_DEBUG, ("CWR "));
1116   }
1117 }
1118
1119 void
1120 tcp_debug_print_pcbs(void)
1121 {
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);
1129   }
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);
1136   }
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);
1143   }
1144 }
1145
1146 s16_t
1147 tcp_pcbs_sane(void)
1148 {
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);
1154   }
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);
1157   }
1158   return 1;
1159 }
1160 #endif /* TCP_DEBUG */
1161 #endif /* LWIP_TCP */
1162
1163
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