tmk_core/tool/mbed/mbed-sdk/libraries/net/lwip/lwip/include/lwip/tcp_impl.h

   1 /*
   2  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without modification,
   6  * are permitted provided that the following conditions are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright notice,
   9  *    this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright notice,
  11  *    this list of conditions and the following disclaimer in the documentation
  12  *    and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  19  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  25  * OF SUCH DAMAGE.
  26  *
  27  * This file is part of the lwIP TCP/IP stack.
  28  *
  29  * Author: Adam Dunkels <adam@sics.se>
  30  *
  31  */
  32 #ifndef __LWIP_TCP_IMPL_H__
  33 #define __LWIP_TCP_IMPL_H__
  34
  35 #include "lwip/opt.h"
  36
  37 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
  38
  39 #include "lwip/tcp.h"
  40 #include "lwip/sys.h"
  41 #include "lwip/mem.h"
  42 #include "lwip/pbuf.h"
  43 #include "lwip/ip.h"
  44 #include "lwip/icmp.h"
  45 #include "lwip/err.h"
  46
  47 #ifdef __cplusplus
  48 extern "C" {
  49 #endif
  50
  51 /* Functions for interfacing with TCP: */
  52
  53 /* Lower layer interface to TCP: */
  54 #define tcp_init() /* Compatibility define, no init needed. */
  55 void             tcp_tmr     (void);  /* Must be called every
  56                                          TCP_TMR_INTERVAL
  57                                          ms. (Typically 250 ms). */
  58 /* It is also possible to call these two functions at the right
  59    intervals (instead of calling tcp_tmr()). */
  60 void             tcp_slowtmr (void);
  61 void             tcp_fasttmr (void);
  62
  63
  64 /* Only used by IP to pass a TCP segment to TCP: */
  65 void             tcp_input   (struct pbuf *p, struct netif *inp);
  66 /* Used within the TCP code only: */
  67 struct tcp_pcb * tcp_alloc   (u8_t prio);
  68 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
  69 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
  70 void             tcp_rexmit  (struct tcp_pcb *pcb);
  71 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
  72 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
  73 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
  74
  75 /**
  76  * This is the Nagle algorithm: try to combine user data to send as few TCP
  77  * segments as possible. Only send if
  78  * - no previously transmitted data on the connection remains unacknowledged or
  79  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
  80  * - the only unsent segment is at least pcb->mss bytes long (or there is more
  81  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
  82  * - or if we are in fast-retransmit (TF_INFR)
  83  */
  84 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
  85                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
  86                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
  87                               ((tpcb)->unsent->len >= (tpcb)->mss))) \
  88                             ) ? 1 : 0)
  89 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
  90
  91
  92 #define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
  93 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
  94 #define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
  95 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
  96 /* is b<=a<=c? */
  97 #if 0 /* see bug #10548 */
  98 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
  99 #endif
 100 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
 101 #define TCP_FIN 0x01U
 102 #define TCP_SYN 0x02U
 103 #define TCP_RST 0x04U
 104 #define TCP_PSH 0x08U
 105 #define TCP_ACK 0x10U
 106 #define TCP_URG 0x20U
 107 #define TCP_ECE 0x40U
 108 #define TCP_CWR 0x80U
 109
 110 #define TCP_FLAGS 0x3fU
 111
 112 /* Length of the TCP header, excluding options. */
 113 #define TCP_HLEN 20
 114
 115 #ifndef TCP_TMR_INTERVAL
 116 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
 117 #endif /* TCP_TMR_INTERVAL */
 118
 119 #ifndef TCP_FAST_INTERVAL
 120 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
 121 #endif /* TCP_FAST_INTERVAL */
 122
 123 #ifndef TCP_SLOW_INTERVAL
 124 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
 125 #endif /* TCP_SLOW_INTERVAL */
 126
 127 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
 128 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
 129
 130 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
 131
 132 #ifndef TCP_MSL
 133 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
 134 #endif
 135
 136 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
 137 #ifndef  TCP_KEEPIDLE_DEFAULT
 138 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
 139 #endif
 140
 141 #ifndef  TCP_KEEPINTVL_DEFAULT
 142 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
 143 #endif
 144
 145 #ifndef  TCP_KEEPCNT_DEFAULT
 146 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
 147 #endif
 148
 149 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
 150
 151 /* Fields are (of course) in network byte order.
 152  * Some fields are converted to host byte order in tcp_input().
 153  */
 154 #ifdef PACK_STRUCT_USE_INCLUDES
 155 #  include "arch/bpstruct.h"
 156 #endif
 157 PACK_STRUCT_BEGIN
 158 struct tcp_hdr {
 159   PACK_STRUCT_FIELD(u16_t src);
 160   PACK_STRUCT_FIELD(u16_t dest);
 161   PACK_STRUCT_FIELD(u32_t seqno);
 162   PACK_STRUCT_FIELD(u32_t ackno);
 163   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
 164   PACK_STRUCT_FIELD(u16_t wnd);
 165   PACK_STRUCT_FIELD(u16_t chksum);
 166   PACK_STRUCT_FIELD(u16_t urgp);
 167 } PACK_STRUCT_STRUCT;
 168 PACK_STRUCT_END
 169 #ifdef PACK_STRUCT_USE_INCLUDES
 170 #  include "arch/epstruct.h"
 171 #endif
 172
 173 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
 174 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
 175 #define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
 176
 177 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
 178 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
 179 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
 180 #define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags))
 181
 182 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
 183 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
 184
 185 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
 186
 187 /** Flags used on input processing, not on pcb->flags
 188 */
 189 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
 190 #define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
 191 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
 192
 193
 194 #if LWIP_EVENT_API
 195
 196 #define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 197                 LWIP_EVENT_ACCEPT, NULL, 0, err)
 198 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 199                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
 200 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 201                 LWIP_EVENT_RECV, (p), 0, (err))
 202 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 203                 LWIP_EVENT_RECV, NULL, 0, ERR_OK)
 204 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 205                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
 206 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 207                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
 208 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
 209                 LWIP_EVENT_ERR, NULL, 0, (err))
 210
 211 #else /* LWIP_EVENT_API */
 212
 213 #define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
 214   do {                                                         \
 215     if((pcb)->accept != NULL)                                  \
 216       (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
 217     else (ret) = ERR_ARG;                                      \
 218   } while (0)
 219
 220 #define TCP_EVENT_SENT(pcb,space,ret)                          \
 221   do {                                                         \
 222     if((pcb)->sent != NULL)                                    \
 223       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
 224     else (ret) = ERR_OK;                                       \
 225   } while (0)
 226
 227 #define TCP_EVENT_RECV(pcb,p,err,ret)                          \
 228   do {                                                         \
 229     if((pcb)->recv != NULL) {                                  \
 230       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\
 231     } else {                                                   \
 232       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));          \
 233     }                                                          \
 234   } while (0)
 235
 236 #define TCP_EVENT_CLOSED(pcb,ret)                                \
 237   do {                                                           \
 238     if(((pcb)->recv != NULL)) {                                  \
 239       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
 240     } else {                                                     \
 241       (ret) = ERR_OK;                                            \
 242     }                                                            \
 243   } while (0)
 244
 245 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
 246   do {                                                           \
 247     if((pcb)->connected != NULL)                                 \
 248       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
 249     else (ret) = ERR_OK;                                         \
 250   } while (0)
 251
 252 #define TCP_EVENT_POLL(pcb,ret)                                \
 253   do {                                                         \
 254     if((pcb)->poll != NULL)                                    \
 255       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
 256     else (ret) = ERR_OK;                                       \
 257   } while (0)
 258
 259 #define TCP_EVENT_ERR(errf,arg,err)                            \
 260   do {                                                         \
 261     if((errf) != NULL)                                         \
 262       (errf)((arg),(err));                                     \
 263   } while (0)
 264
 265 #endif /* LWIP_EVENT_API */
 266
 267 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
 268 #if TCP_OVERSIZE && defined(LWIP_DEBUG)
 269 #define TCP_OVERSIZE_DBGCHECK 1
 270 #else
 271 #define TCP_OVERSIZE_DBGCHECK 0
 272 #endif
 273
 274 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
 275 #define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)
 276
 277 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
 278 struct tcp_seg {
 279   struct tcp_seg *next;    /* used when putting segements on a queue */
 280   struct pbuf *p;          /* buffer containing data + TCP header */
 281   u16_t len;               /* the TCP length of this segment */
 282 #if TCP_OVERSIZE_DBGCHECK
 283   u16_t oversize_left;     /* Extra bytes available at the end of the last
 284                               pbuf in unsent (used for asserting vs.
 285                               tcp_pcb.unsent_oversized only) */
 286 #endif /* TCP_OVERSIZE_DBGCHECK */
 287 #if TCP_CHECKSUM_ON_COPY
 288   u16_t chksum;
 289   u8_t  chksum_swapped;
 290 #endif /* TCP_CHECKSUM_ON_COPY */
 291   u8_t  flags;
 292 #define TF_SEG_OPTS_MSS         (u8_t)0x01U /* Include MSS option. */
 293 #define TF_SEG_OPTS_TS          (u8_t)0x02U /* Include timestamp option. */
 294 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
 295                                                checksummed into 'chksum' */
 296   struct tcp_hdr *tcphdr;  /* the TCP header */
 297 };
 298
 299 #define LWIP_TCP_OPT_LENGTH(flags)              \
 300   (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
 301   (flags & TF_SEG_OPTS_TS  ? 12 : 0)
 302
 303 /** This returns a TCP header option for MSS in an u32_t */
 304 #define TCP_BUILD_MSS_OPTION(x) (x) = PP_HTONL(((u32_t)2 << 24) |          \
 305                                                ((u32_t)4 << 16) |          \
 306                                                (((u32_t)TCP_MSS / 256) << 8) | \
 307                                                (TCP_MSS & 255))
 308
 309 /* Global variables: */
 310 extern struct tcp_pcb *tcp_input_pcb;
 311 extern u32_t tcp_ticks;
 312
 313 /* The TCP PCB lists. */
 314 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
 315   struct tcp_pcb_listen *listen_pcbs;
 316   struct tcp_pcb *pcbs;
 317 };
 318 extern struct tcp_pcb *tcp_bound_pcbs;
 319 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
 320 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
 321               state in which they accept or send
 322               data. */
 323 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
 324
 325 extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
 326
 327 /* Axioms about the above lists:
 328    1) Every TCP PCB that is not CLOSED is in one of the lists.
 329    2) A PCB is only in one of the lists.
 330    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
 331    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
 332 */
 333 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
 334    with a PCB list or removes a PCB from a list, respectively. */
 335 #ifndef TCP_DEBUG_PCB_LISTS
 336 #define TCP_DEBUG_PCB_LISTS 0
 337 #endif
 338 #if TCP_DEBUG_PCB_LISTS
 339 #define TCP_REG(pcbs, npcb) do {\
 340                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \
 341                             for(tcp_tmp_pcb = *(pcbs); \
 342           tcp_tmp_pcb != NULL; \
 343         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 344                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \
 345                             } \
 346                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \
 347                             (npcb)->next = *(pcbs); \
 348                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \
 349                             *(pcbs) = (npcb); \
 350                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 351               tcp_timer_needed(); \
 352                             } while(0)
 353 #define TCP_RMV(pcbs, npcb) do { \
 354                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \
 355                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \
 356                             if(*(pcbs) == (npcb)) { \
 357                                *(pcbs) = (*pcbs)->next; \
 358                             } else for(tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 359                                if(tcp_tmp_pcb->next == (npcb)) { \
 360                                   tcp_tmp_pcb->next = (npcb)->next; \
 361                                   break; \
 362                                } \
 363                             } \
 364                             (npcb)->next = NULL; \
 365                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 366                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \
 367                             } while(0)
 368
 369 #else /* LWIP_DEBUG */
 370
 371 #define TCP_REG(pcbs, npcb)                        \
 372   do {                                             \
 373     (npcb)->next = *pcbs;                          \
 374     *(pcbs) = (npcb);                              \
 375     tcp_timer_needed();                            \
 376   } while (0)
 377
 378 #define TCP_RMV(pcbs, npcb)                        \
 379   do {                                             \
 380     if(*(pcbs) == (npcb)) {                        \
 381       (*(pcbs)) = (*pcbs)->next;                   \
 382     }                                              \
 383     else {                                         \
 384       for(tcp_tmp_pcb = *pcbs;                     \
 385           tcp_tmp_pcb != NULL;                     \
 386           tcp_tmp_pcb = tcp_tmp_pcb->next) {       \
 387         if(tcp_tmp_pcb->next == (npcb)) {          \
 388           tcp_tmp_pcb->next = (npcb)->next;        \
 389           break;                                   \
 390         }                                          \
 391       }                                            \
 392     }                                              \
 393     (npcb)->next = NULL;                           \
 394   } while(0)
 395
 396 #endif /* LWIP_DEBUG */
 397
 398
 399 /* Internal functions: */
 400 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
 401 void tcp_pcb_purge(struct tcp_pcb *pcb);
 402 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
 403
 404 void tcp_segs_free(struct tcp_seg *seg);
 405 void tcp_seg_free(struct tcp_seg *seg);
 406 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
 407
 408 #define tcp_ack(pcb)                               \
 409   do {                                             \
 410     if((pcb)->flags & TF_ACK_DELAY) {              \
 411       (pcb)->flags &= ~TF_ACK_DELAY;               \
 412       (pcb)->flags |= TF_ACK_NOW;                  \
 413     }                                              \
 414     else {                                         \
 415       (pcb)->flags |= TF_ACK_DELAY;                \
 416     }                                              \
 417   } while (0)
 418
 419 #define tcp_ack_now(pcb)                           \
 420   do {                                             \
 421     (pcb)->flags |= TF_ACK_NOW;                    \
 422   } while (0)
 423
 424 err_t tcp_send_fin(struct tcp_pcb *pcb);
 425 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);
 426
 427 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
 428
 429 void tcp_rst(u32_t seqno, u32_t ackno,
 430        ip_addr_t *local_ip, ip_addr_t *remote_ip,
 431        u16_t local_port, u16_t remote_port);
 432
 433 u32_t tcp_next_iss(void);
 434
 435 void tcp_keepalive(struct tcp_pcb *pcb);
 436 void tcp_zero_window_probe(struct tcp_pcb *pcb);
 437
 438 #if TCP_CALCULATE_EFF_SEND_MSS
 439 u16_t tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr);
 440 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
 441
 442 #if LWIP_CALLBACK_API
 443 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
 444 #endif /* LWIP_CALLBACK_API */
 445
 446 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
 447 void tcp_debug_print(struct tcp_hdr *tcphdr);
 448 void tcp_debug_print_flags(u8_t flags);
 449 void tcp_debug_print_state(enum tcp_state s);
 450 void tcp_debug_print_pcbs(void);
 451 s16_t tcp_pcbs_sane(void);
 452 #else
 453 #  define tcp_debug_print(tcphdr)
 454 #  define tcp_debug_print_flags(flags)
 455 #  define tcp_debug_print_state(s)
 456 #  define tcp_debug_print_pcbs()
 457 #  define tcp_pcbs_sane() 1
 458 #endif /* TCP_DEBUG */
 459
 460 /** External function (implemented in timers.c), called when TCP detects
 461  * that a timer is needed (i.e. active- or time-wait-pcb found). */
 462 void tcp_timer_needed(void);
 463
 464
 465 #ifdef __cplusplus
 466 }
 467 #endif
 468
 469 #endif /* LWIP_TCP */
 470
 471 #endif /* __LWIP_TCP_H__ */