minix/lib/liblwip/dist/src/include/lwip/priv/tcp_priv.h

   1 /**
   2  * @file
   3  * TCP internal implementations (do not use in application code)
   4  */
   5
   6 /*
   7  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without modification,
  11  * are permitted provided that the following conditions are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright notice,
  14  *    this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright notice,
  16  *    this list of conditions and the following disclaimer in the documentation
  17  *    and/or other materials provided with the distribution.
  18  * 3. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  24  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  26  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  29  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  30  * OF SUCH DAMAGE.
  31  *
  32  * This file is part of the lwIP TCP/IP stack.
  33  *
  34  * Author: Adam Dunkels <adam@sics.se>
  35  *
  36  */
  37 #ifndef LWIP_HDR_TCP_PRIV_H
  38 #define LWIP_HDR_TCP_PRIV_H
  39
  40 #include "lwip/opt.h"
  41
  42 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
  43
  44 #include "lwip/tcp.h"
  45 #include "lwip/mem.h"
  46 #include "lwip/pbuf.h"
  47 #include "lwip/ip.h"
  48 #include "lwip/icmp.h"
  49 #include "lwip/err.h"
  50 #include "lwip/ip6.h"
  51 #include "lwip/ip6_addr.h"
  52 #include "lwip/prot/tcp.h"
  53
  54 #ifdef __cplusplus
  55 extern "C" {
  56 #endif
  57
  58 /* Functions for interfacing with TCP: */
  59
  60 /* Lower layer interface to TCP: */
  61 void             tcp_init    (void);  /* Initialize this module. */
  62 void             tcp_tmr     (void);  /* Must be called every
  63                                          TCP_TMR_INTERVAL
  64                                          ms. (Typically 250 ms). */
  65 /* It is also possible to call these two functions at the right
  66    intervals (instead of calling tcp_tmr()). */
  67 void             tcp_slowtmr (void);
  68 void             tcp_fasttmr (void);
  69
  70 /* Call this from a netif driver (watch out for threading issues!) that has
  71    returned a memory error on transmit and now has free buffers to send more.
  72    This iterates all active pcbs that had an error and tries to call
  73    tcp_output, so use this with care as it might slow down the system. */
  74 void             tcp_txnow   (void);
  75
  76 /* Only used by IP to pass a TCP segment to TCP: */
  77 void             tcp_input   (struct pbuf *p, struct netif *inp);
  78 /* Used within the TCP code only: */
  79 struct tcp_pcb * tcp_alloc   (u8_t prio);
  80 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
  81 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
  82 void             tcp_rexmit  (struct tcp_pcb *pcb);
  83 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
  84 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
  85 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
  86 err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
  87
  88 /**
  89  * This is the Nagle algorithm: try to combine user data to send as few TCP
  90  * segments as possible. Only send if
  91  * - no previously transmitted data on the connection remains unacknowledged or
  92  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
  93  * - the only unsent segment is at least pcb->mss bytes long (or there is more
  94  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
  95  * - or if we are in fast-retransmit (TF_INFR)
  96  */
  97 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
  98                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
  99                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
 100                               ((tpcb)->unsent->len >= (tpcb)->mss))) || \
 101                             ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \
 102                             ) ? 1 : 0)
 103 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
 104
 105
 106 #define TCP_SEQ_LT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0)
 107 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0)
 108 #define TCP_SEQ_GT(a,b)     ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0)
 109 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0)
 110 /* is b<=a<=c? */
 111 #if 0 /* see bug #10548 */
 112 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
 113 #endif
 114 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
 115
 116 #ifndef TCP_TMR_INTERVAL
 117 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
 118 #endif /* TCP_TMR_INTERVAL */
 119
 120 #ifndef TCP_FAST_INTERVAL
 121 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
 122 #endif /* TCP_FAST_INTERVAL */
 123
 124 #ifndef TCP_SLOW_INTERVAL
 125 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
 126 #endif /* TCP_SLOW_INTERVAL */
 127
 128 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
 129 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
 130
 131 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
 132
 133 #ifndef TCP_MSL
 134 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
 135 #endif
 136
 137 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
 138 #ifndef  TCP_KEEPIDLE_DEFAULT
 139 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
 140 #endif
 141
 142 #ifndef  TCP_KEEPINTVL_DEFAULT
 143 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
 144 #endif
 145
 146 #ifndef  TCP_KEEPCNT_DEFAULT
 147 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
 148 #endif
 149
 150 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
 151
 152 #define TCP_TCPLEN(seg) ((seg)->len + (((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0) ? 1U : 0U))
 153
 154 /** Flags used on input processing, not on pcb->flags
 155 */
 156 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
 157 #define TF_CLOSED    (u8_t)0x10U   /* Connection was successfully closed. */
 158 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
 159
 160
 161 #if LWIP_EVENT_API
 162
 163 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret) ret = lwip_tcp_event(arg, (pcb),\
 164                 LWIP_EVENT_ACCEPT, NULL, 0, err)
 165 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 166                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
 167 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 168                 LWIP_EVENT_RECV, (p), 0, (err))
 169 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 170                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
 171 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 172                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
 173 #define TCP_EVENT_POLL(pcb,ret)       do { if ((pcb)->state != SYN_RCVD) {                          \
 174                 ret = lwip_tcp_event((pcb)->callback_arg, (pcb), LWIP_EVENT_POLL, NULL, 0, ERR_OK); \
 175                 } else {                                                                            \
 176                 ret = ERR_ARG; } } while(0)
 177 #define TCP_EVENT_ERR(last_state,errf,arg,err)  do { if (last_state != SYN_RCVD) {                \
 178                 lwip_tcp_event((arg), NULL, LWIP_EVENT_ERR, NULL, 0, (err)); } } while(0)
 179
 180 #else /* LWIP_EVENT_API */
 181
 182 #define TCP_EVENT_ACCEPT(lpcb,pcb,arg,err,ret)                 \
 183   do {                                                         \
 184     if((lpcb)->accept != NULL)                                 \
 185       (ret) = (lpcb)->accept((arg),(pcb),(err));               \
 186     else (ret) = ERR_ARG;                                      \
 187   } while (0)
 188
 189 #define TCP_EVENT_SENT(pcb,space,ret)                          \
 190   do {                                                         \
 191     if((pcb)->sent != NULL)                                    \
 192       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
 193     else (ret) = ERR_OK;                                       \
 194   } while (0)
 195
 196 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
 197   do {                                                         \
 198     if((pcb)->recv != NULL) {                                  \
 199       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
 200     } else {                                                   \
 201       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
 202     }                                                          \
 203   } while (0)
 204
 205 #define TCP_EVENT_CLOSED(pcb,ret)                                \
 206   do {                                                           \
 207     if(((pcb)->recv != NULL)) {                                  \
 208       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
 209     } else {                                                     \
 210       (ret) = ERR_OK;                                            \
 211     }                                                            \
 212   } while (0)
 213
 214 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
 215   do {                                                           \
 216     if((pcb)->connected != NULL)                                 \
 217       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
 218     else (ret) = ERR_OK;                                         \
 219   } while (0)
 220
 221 #define TCP_EVENT_POLL(pcb,ret)                                \
 222   do {                                                         \
 223     if((pcb)->poll != NULL)                                    \
 224       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
 225     else (ret) = ERR_OK;                                       \
 226   } while (0)
 227
 228 #define TCP_EVENT_ERR(last_state,errf,arg,err)                 \
 229   do {                                                         \
 230     LWIP_UNUSED_ARG(last_state);                               \
 231     if((errf) != NULL)                                         \
 232       (errf)((arg),(err));                                     \
 233   } while (0)
 234
 235 #endif /* LWIP_EVENT_API */
 236
 237 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
 238 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
 239 #define TCP_OVERSIZE_DBGCHECK 1
 240 #else
 241 #define TCP_OVERSIZE_DBGCHECK 0
 242 #endif
 243
 244 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
 245 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
 246
 247 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
 248 struct tcp_seg {
 249   struct tcp_seg *next;    /* used when putting segments on a queue */
 250   struct pbuf *p;          /* buffer containing data + TCP header */
 251   u16_t len;               /* the TCP length of this segment */
 252 #if TCP_OVERSIZE_DBGCHECK
 253   u16_t oversize_left;     /* Extra bytes available at the end of the last
 254                               pbuf in unsent (used for asserting vs.
 255                               tcp_pcb.unsent_oversize only) */
 256 #endif /* TCP_OVERSIZE_DBGCHECK */
 257 #if TCP_CHECKSUM_ON_COPY
 258   u16_t chksum;
 259   u8_t  chksum_swapped;
 260 #endif /* TCP_CHECKSUM_ON_COPY */
 261   u8_t  flags;
 262 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
 263 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
 264 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
 265                                                checksummed into 'chksum' */
 266 #define TF_SEG_OPTS_WND_SCALE   (u8_t)0x08U /* Include WND SCALE option */
 267   struct tcp_hdr *tcphdr;  /* the TCP header */
 268 };
 269
 270 #define LWIP_TCP_OPT_EOL        0
 271 #define LWIP_TCP_OPT_NOP        1
 272 #define LWIP_TCP_OPT_MSS        2
 273 #define LWIP_TCP_OPT_WS         3
 274 #define LWIP_TCP_OPT_TS         8
 275
 276 #define LWIP_TCP_OPT_LEN_MSS    4
 277 #if LWIP_TCP_TIMESTAMPS
 278 #define LWIP_TCP_OPT_LEN_TS     10
 279 #define LWIP_TCP_OPT_LEN_TS_OUT 12 /* aligned for output (includes NOP padding) */
 280 #else
 281 #define LWIP_TCP_OPT_LEN_TS_OUT 0
 282 #endif
 283 #if LWIP_WND_SCALE
 284 #define LWIP_TCP_OPT_LEN_WS     3
 285 #define LWIP_TCP_OPT_LEN_WS_OUT 4 /* aligned for output (includes NOP padding) */
 286 #else
 287 #define LWIP_TCP_OPT_LEN_WS_OUT 0
 288 #endif
 289
 290 #define LWIP_TCP_OPT_LENGTH(flags) \
 291   (flags & TF_SEG_OPTS_MSS       ? LWIP_TCP_OPT_LEN_MSS    : 0) + \
 292   (flags & TF_SEG_OPTS_TS        ? LWIP_TCP_OPT_LEN_TS_OUT : 0) + \
 293   (flags & TF_SEG_OPTS_WND_SCALE ? LWIP_TCP_OPT_LEN_WS_OUT : 0)
 294
 295 /** This returns a TCP header option for MSS in an u32_t */
 296 #define TCP_BUILD_MSS_OPTION(mss) lwip_htonl(0x02040000 | ((mss) & 0xFFFF))
 297
 298 #if LWIP_WND_SCALE
 299 #define TCPWNDSIZE_F       U32_F
 300 #define TCPWND_MAX         0xFFFFFFFFU
 301 #define TCPWND_CHECK16(x)  LWIP_ASSERT("window size > 0xFFFF", (x) <= 0xFFFF)
 302 #define TCPWND_MIN16(x)    ((u16_t)LWIP_MIN((x), 0xFFFF))
 303 #else /* LWIP_WND_SCALE */
 304 #define TCPWNDSIZE_F       U16_F
 305 #define TCPWND_MAX         0xFFFFU
 306 #define TCPWND_CHECK16(x)
 307 #define TCPWND_MIN16(x)    x
 308 #endif /* LWIP_WND_SCALE */
 309
 310 /* Global variables: */
 311 extern struct tcp_pcb *tcp_input_pcb;
 312 extern u32_t tcp_ticks;
 313 extern u8_t tcp_active_pcbs_changed;
 314
 315 /* The TCP PCB lists. */
 316 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
 317   struct tcp_pcb_listen *listen_pcbs;
 318   struct tcp_pcb *pcbs;
 319 };
 320 extern struct tcp_pcb *tcp_bound_pcbs;
 321 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
 322 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
 323               state in which they accept or send
 324               data. */
 325 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
 326
 327 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT  3
 328 #define NUM_TCP_PCB_LISTS               4
 329 extern struct tcp_pcb ** const tcp_pcb_lists[NUM_TCP_PCB_LISTS];
 330
 331 /* Axioms about the above lists:
 332    1) Every TCP PCB that is not CLOSED is in one of the lists.
 333    2) A PCB is only in one of the lists.
 334    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
 335    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
 336 */
 337 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
 338    with a PCB list or removes a PCB from a list, respectively. */
 339 #ifndef TCP_DEBUG_PCB_LISTS
 340 #define TCP_DEBUG_PCB_LISTS 0
 341 #endif
 342 #if TCP_DEBUG_PCB_LISTS
 343 #define TCP_REG(pcbs, npcb) do {\
 344                             struct tcp_pcb *tcp_tmp_pcb; \
 345                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
 346                             for (tcp_tmp_pcb = *(pcbs); \
 347           tcp_tmp_pcb != NULL; \
 348         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 349                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
 350                             } \
 351                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
 352                             (npcb)->next = *(pcbs); \
 353                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
 354                             *(pcbs) = (npcb); \
 355                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 356               tcp_timer_needed(); \
 357                             } while(0)
 358 #define TCP_RMV(pcbs, npcb) do { \
 359                             struct tcp_pcb *tcp_tmp_pcb; \
 360                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
 361                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
 362                             if(*(pcbs) == (npcb)) { \
 363                                *(pcbs) = (*pcbs)->next; \
 364                             } else for (tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 365                                if(tcp_tmp_pcb->next == (npcb)) { \
 366                                   tcp_tmp_pcb->next = (npcb)->next; \
 367                                   break; \
 368                                } \
 369                             } \
 370                             (npcb)->next = NULL; \
 371                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 372                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
 373                             } while(0)
 374
 375 #else /* LWIP_DEBUG */
 376
 377 #define TCP_REG(pcbs, npcb)                        \
 378   do {                                             \
 379     (npcb)->next = *pcbs;                          \
 380     *(pcbs) = (npcb);                              \
 381     tcp_timer_needed();                            \
 382   } while (0)
 383
 384 #define TCP_RMV(pcbs, npcb)                        \
 385   do {                                             \
 386     if(*(pcbs) == (npcb)) {                        \
 387       (*(pcbs)) = (*pcbs)->next;                   \
 388     }                                              \
 389     else {                                         \
 390       struct tcp_pcb *tcp_tmp_pcb;                 \
 391       for (tcp_tmp_pcb = *pcbs;                    \
 392           tcp_tmp_pcb != NULL;                     \
 393           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
 394         if(tcp_tmp_pcb->next == (npcb)) {          \
 395           tcp_tmp_pcb->next = (npcb)->next;        \
 396           break;                                   \
 397         }                                          \
 398       }                                            \
 399     }                                              \
 400     (npcb)->next = NULL;                           \
 401   } while(0)
 402
 403 #endif /* LWIP_DEBUG */
 404
 405 #define TCP_REG_ACTIVE(npcb)                       \
 406   do {                                             \
 407     TCP_REG(&tcp_active_pcbs, npcb);               \
 408     tcp_active_pcbs_changed = 1;                   \
 409   } while (0)
 410
 411 #define TCP_RMV_ACTIVE(npcb)                       \
 412   do {                                             \
 413     TCP_RMV(&tcp_active_pcbs, npcb);               \
 414     tcp_active_pcbs_changed = 1;                   \
 415   } while (0)
 416
 417 #define TCP_PCB_REMOVE_ACTIVE(pcb)                 \
 418   do {                                             \
 419     tcp_pcb_remove(&tcp_active_pcbs, pcb);         \
 420     tcp_active_pcbs_changed = 1;                   \
 421   } while (0)
 422
 423
 424 /* Internal functions: */
 425 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
 426 void tcp_pcb_purge(struct tcp_pcb *pcb);
 427 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
 428
 429 void tcp_segs_free(struct tcp_seg *seg);
 430 void tcp_seg_free(struct tcp_seg *seg);
 431 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
 432
 433 #define tcp_ack(pcb)                               \
 434   do {                                             \
 435     if((pcb)->flags & TF_ACK_DELAY) {              \
 436       (pcb)->flags &= ~TF_ACK_DELAY;               \
 437       (pcb)->flags |= TF_ACK_NOW;                  \
 438     }                                              \
 439     else {                                         \
 440       (pcb)->flags |= TF_ACK_DELAY;                \
 441     }                                              \
 442   } while (0)
 443
 444 #define tcp_ack_now(pcb)                           \
 445   do {                                             \
 446     (pcb)->flags |= TF_ACK_NOW;                    \
 447   } while (0)
 448
 449 err_t tcp_send_fin(struct tcp_pcb *pcb);
 450 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
 451
 452 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
 453
 454 void tcp_rst(u32_t seqno, u32_t ackno,
 455        const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
 456        u16_t local_port, u16_t remote_port);
 457
 458 u32_t tcp_next_iss(struct tcp_pcb *pcb);
 459
 460 err_t tcp_keepalive(struct tcp_pcb *pcb);
 461 err_t tcp_zero_window_probe(struct tcp_pcb *pcb);
 462 void  tcp_trigger_input_pcb_close(void);
 463
 464 #if TCP_CALCULATE_EFF_SEND_MSS
 465 u16_t tcp_eff_send_mss_netif(u16_t sendmss, struct netif *outif,
 466                              const ip_addr_t *dest);
 467 #define tcp_eff_send_mss(sendmss, src, dest) \
 468     tcp_eff_send_mss_netif(sendmss, ip_route(src, dest), dest)
 469 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
 470
 471 #if LWIP_CALLBACK_API
 472 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
 473 #endif /* LWIP_CALLBACK_API */
 474
 475 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
 476 void tcp_debug_print(struct tcp_hdr *tcphdr);
 477 void tcp_debug_print_flags(u8_t flags);
 478 void tcp_debug_print_state(enum tcp_state s);
 479 void tcp_debug_print_pcbs(void);
 480 s16_t tcp_pcbs_sane(void);
 481 #else
 482 #  define tcp_debug_print(tcphdr)
 483 #  define tcp_debug_print_flags(flags)
 484 #  define tcp_debug_print_state(s)
 485 #  define tcp_debug_print_pcbs()
 486 #  define tcp_pcbs_sane() 1
 487 #endif /* TCP_DEBUG */
 488
 489 /** External function (implemented in timers.c), called when TCP detects
 490  * that a timer is needed (i.e. active- or time-wait-pcb found). */
 491 void tcp_timer_needed(void);
 492
 493 void tcp_netif_ip_addr_changed(const ip_addr_t* old_addr, const ip_addr_t* new_addr);
 494
 495 #ifdef __cplusplus
 496 }
 497 #endif
 498
 499 #endif /* LWIP_TCP */
 500
 501 #endif /* LWIP_HDR_TCP_PRIV_H */