FreeRTOS/Common/ethernet/lwIP_132/src/include/lwip/tcp.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_H__
  33 #define __LWIP_TCP_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/sys.h"
  40 #include "lwip/mem.h"
  41 #include "lwip/pbuf.h"
  42 #include "lwip/ip.h"
  43 #include "lwip/icmp.h"
  44 #include "lwip/err.h"
  45
  46 #ifdef __cplusplus
  47 extern "C" {
  48 #endif
  49
  50 struct tcp_pcb;
  51
  52 /* Functions for interfacing with TCP: */
  53
  54 /* Lower layer interface to TCP: */
  55 #define tcp_init() /* Compatibility define, not init needed. */
  56 void             tcp_tmr     (void);  /* Must be called every
  57                                          TCP_TMR_INTERVAL
  58                                          ms. (Typically 250 ms). */
  59 /* Application program's interface: */
  60 struct tcp_pcb * tcp_new     (void);
  61 struct tcp_pcb * tcp_alloc   (u8_t prio);
  62
  63 void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
  64 void             tcp_accept  (struct tcp_pcb *pcb,
  65                               err_t (* accept)(void *arg, struct tcp_pcb *newpcb,
  66                  err_t err));
  67 void             tcp_recv    (struct tcp_pcb *pcb,
  68                               err_t (* recv)(void *arg, struct tcp_pcb *tpcb,
  69                               struct pbuf *p, err_t err));
  70 void             tcp_sent    (struct tcp_pcb *pcb,
  71                               err_t (* sent)(void *arg, struct tcp_pcb *tpcb,
  72                               u16_t len));
  73 void             tcp_poll    (struct tcp_pcb *pcb,
  74                               err_t (* poll)(void *arg, struct tcp_pcb *tpcb),
  75                               u8_t interval);
  76 void             tcp_err     (struct tcp_pcb *pcb,
  77                               void (* err)(void *arg, err_t err));
  78
  79 #define          tcp_mss(pcb)      ((pcb)->mss)
  80 #define          tcp_sndbuf(pcb)   ((pcb)->snd_buf)
  81 #define          tcp_nagle_disable(pcb)  ((pcb)->flags |= TF_NODELAY)
  82 #define          tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY)
  83 #define          tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0)
  84
  85 #if TCP_LISTEN_BACKLOG
  86 #define          tcp_accepted(pcb) (((struct tcp_pcb_listen *)(pcb))->accepts_pending--)
  87 #else  /* TCP_LISTEN_BACKLOG */
  88 #define          tcp_accepted(pcb)
  89 #endif /* TCP_LISTEN_BACKLOG */
  90
  91 void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
  92 err_t            tcp_bind    (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
  93                               u16_t port);
  94 err_t            tcp_connect (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
  95                               u16_t port, err_t (* connected)(void *arg,
  96                               struct tcp_pcb *tpcb,
  97                               err_t err));
  98
  99 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
 100 #define          tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
 101
 102 void             tcp_abandon (struct tcp_pcb *pcb, int reset);
 103 #define          tcp_abort(pcb) tcp_abandon((pcb), 1)
 104 err_t            tcp_close   (struct tcp_pcb *pcb);
 105
 106 /* Flags for "apiflags" parameter in tcp_write and tcp_enqueue */
 107 #define TCP_WRITE_FLAG_COPY 0x01
 108 #define TCP_WRITE_FLAG_MORE 0x02
 109
 110 err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
 111                               u8_t apiflags);
 112
 113 void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
 114
 115 #define TCP_PRIO_MIN    1
 116 #define TCP_PRIO_NORMAL 64
 117 #define TCP_PRIO_MAX    127
 118
 119 /* It is also possible to call these two functions at the right
 120    intervals (instead of calling tcp_tmr()). */
 121 void             tcp_slowtmr (void);
 122 void             tcp_fasttmr (void);
 123
 124
 125 /* Only used by IP to pass a TCP segment to TCP: */
 126 void             tcp_input   (struct pbuf *p, struct netif *inp);
 127 /* Used within the TCP code only: */
 128 err_t            tcp_send_empty_ack(struct tcp_pcb *pcb);
 129 err_t            tcp_output  (struct tcp_pcb *pcb);
 130 void             tcp_rexmit  (struct tcp_pcb *pcb);
 131 void             tcp_rexmit_rto  (struct tcp_pcb *pcb);
 132 void             tcp_rexmit_fast (struct tcp_pcb *pcb);
 133 u32_t            tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb);
 134
 135 /**
 136  * This is the Nagle algorithm: try to combine user data to send as few TCP
 137  * segments as possible. Only send if
 138  * - no previously transmitted data on the connection remains unacknowledged or
 139  * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or
 140  * - the only unsent segment is at least pcb->mss bytes long (or there is more
 141  *   than one unsent segment - with lwIP, this can happen although unsent->len < mss)
 142  * - or if we are in fast-retransmit (TF_INFR)
 143  */
 144 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \
 145                             ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \
 146                             (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \
 147                               ((tpcb)->unsent->len >= (tpcb)->mss))) \
 148                             ) ? 1 : 0)
 149 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK)
 150
 151
 152 #define TCP_SEQ_LT(a,b)     ((s32_t)((a)-(b)) < 0)
 153 #define TCP_SEQ_LEQ(a,b)    ((s32_t)((a)-(b)) <= 0)
 154 #define TCP_SEQ_GT(a,b)     ((s32_t)((a)-(b)) > 0)
 155 #define TCP_SEQ_GEQ(a,b)    ((s32_t)((a)-(b)) >= 0)
 156 /* is b<=a<=c? */
 157 #if 0 /* see bug #10548 */
 158 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b))
 159 #endif
 160 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
 161 #define TCP_FIN 0x01U
 162 #define TCP_SYN 0x02U
 163 #define TCP_RST 0x04U
 164 #define TCP_PSH 0x08U
 165 #define TCP_ACK 0x10U
 166 #define TCP_URG 0x20U
 167 #define TCP_ECE 0x40U
 168 #define TCP_CWR 0x80U
 169
 170 #define TCP_FLAGS 0x3fU
 171
 172 /* Length of the TCP header, excluding options. */
 173 #define TCP_HLEN 20
 174
 175 #ifndef TCP_TMR_INTERVAL
 176 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
 177 #endif /* TCP_TMR_INTERVAL */
 178
 179 #ifndef TCP_FAST_INTERVAL
 180 #define TCP_FAST_INTERVAL      TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */
 181 #endif /* TCP_FAST_INTERVAL */
 182
 183 #ifndef TCP_SLOW_INTERVAL
 184 #define TCP_SLOW_INTERVAL      (2*TCP_TMR_INTERVAL)  /* the coarse grained timeout in milliseconds */
 185 #endif /* TCP_SLOW_INTERVAL */
 186
 187 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */
 188 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */
 189
 190 #define TCP_OOSEQ_TIMEOUT        6U /* x RTO */
 191
 192 #ifndef TCP_MSL
 193 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */
 194 #endif
 195
 196 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */
 197 #ifndef  TCP_KEEPIDLE_DEFAULT
 198 #define  TCP_KEEPIDLE_DEFAULT     7200000UL /* Default KEEPALIVE timer in milliseconds */
 199 #endif
 200
 201 #ifndef  TCP_KEEPINTVL_DEFAULT
 202 #define  TCP_KEEPINTVL_DEFAULT    75000UL   /* Default Time between KEEPALIVE probes in milliseconds */
 203 #endif
 204
 205 #ifndef  TCP_KEEPCNT_DEFAULT
 206 #define  TCP_KEEPCNT_DEFAULT      9U        /* Default Counter for KEEPALIVE probes */
 207 #endif
 208
 209 #define  TCP_MAXIDLE              TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT  /* Maximum KEEPALIVE probe time */
 210
 211 /* Fields are (of course) in network byte order.
 212  * Some fields are converted to host byte order in tcp_input().
 213  */
 214 #ifdef PACK_STRUCT_USE_INCLUDES
 215 #  include "arch/bpstruct.h"
 216 #endif
 217 PACK_STRUCT_BEGIN
 218 struct tcp_hdr {
 219   PACK_STRUCT_FIELD(u16_t src);
 220   PACK_STRUCT_FIELD(u16_t dest);
 221   PACK_STRUCT_FIELD(u32_t seqno);
 222   PACK_STRUCT_FIELD(u32_t ackno);
 223   PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags);
 224   PACK_STRUCT_FIELD(u16_t wnd);
 225   PACK_STRUCT_FIELD(u16_t chksum);
 226   PACK_STRUCT_FIELD(u16_t urgp);
 227 } PACK_STRUCT_STRUCT;
 228 PACK_STRUCT_END
 229 #ifdef PACK_STRUCT_USE_INCLUDES
 230 #  include "arch/epstruct.h"
 231 #endif
 232
 233 #define TCPH_OFFSET(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 8)
 234 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12)
 235 #define TCPH_FLAGS(phdr)  (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS)
 236
 237 #define TCPH_OFFSET_SET(phdr, offset) (phdr)->_hdrlen_rsvd_flags = htons(((offset) << 8) | TCPH_FLAGS(phdr))
 238 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr))
 239 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & htons((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags))
 240 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags))
 241 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) )
 242
 243 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0))
 244
 245 enum tcp_state {
 246   CLOSED      = 0,
 247   LISTEN      = 1,
 248   SYN_SENT    = 2,
 249   SYN_RCVD    = 3,
 250   ESTABLISHED = 4,
 251   FIN_WAIT_1  = 5,
 252   FIN_WAIT_2  = 6,
 253   CLOSE_WAIT  = 7,
 254   CLOSING     = 8,
 255   LAST_ACK    = 9,
 256   TIME_WAIT   = 10
 257 };
 258
 259 /** Flags used on input processing, not on pcb->flags
 260 */
 261 #define TF_RESET     (u8_t)0x08U   /* Connection was reset. */
 262 #define TF_CLOSED    (u8_t)0x10U   /* Connection was sucessfully closed. */
 263 #define TF_GOT_FIN   (u8_t)0x20U   /* Connection was closed by the remote end. */
 264
 265
 266 #if LWIP_CALLBACK_API
 267   /* Function to call when a listener has been connected.
 268    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 269    * @param pcb a new tcp_pcb that now is connected
 270    * @param err an error argument (TODO: that is current always ERR_OK?)
 271    * @return ERR_OK: accept the new connection,
 272    *                 any other err_t abortsthe new connection
 273    */
 274 #define DEF_ACCEPT_CALLBACK  err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err)
 275 #else /* LWIP_CALLBACK_API */
 276 #define DEF_ACCEPT_CALLBACK
 277 #endif /* LWIP_CALLBACK_API */
 278
 279 /**
 280  * members common to struct tcp_pcb and struct tcp_listen_pcb
 281  */
 282 #define TCP_PCB_COMMON(type) \
 283   type *next; /* for the linked list */ \
 284   enum tcp_state state; /* TCP state */ \
 285   u8_t prio; \
 286   void *callback_arg; \
 287   /* ports are in host byte order */ \
 288   u16_t local_port; \
 289   /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
 290   DEF_ACCEPT_CALLBACK
 291
 292
 293 /* the TCP protocol control block */
 294 struct tcp_pcb {
 295 /** common PCB members */
 296   IP_PCB;
 297 /** protocol specific PCB members */
 298   TCP_PCB_COMMON(struct tcp_pcb);
 299
 300   /* ports are in host byte order */
 301   u16_t remote_port;
 302
 303   u8_t flags;
 304 #define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
 305 #define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
 306 #define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
 307 #define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
 308 #define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
 309 #define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
 310 #define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
 311
 312   /* the rest of the fields are in host byte order
 313      as we have to do some math with them */
 314   /* receiver variables */
 315   u32_t rcv_nxt;   /* next seqno expected */
 316   u16_t rcv_wnd;   /* receiver window available */
 317   u16_t rcv_ann_wnd; /* receiver window to announce */
 318   u32_t rcv_ann_right_edge; /* announced right edge of window */
 319
 320   /* Timers */
 321   u32_t tmr;
 322   u8_t polltmr, pollinterval;
 323
 324   /* Retransmission timer. */
 325   s16_t rtime;
 326
 327   u16_t mss;   /* maximum segment size */
 328
 329   /* RTT (round trip time) estimation variables */
 330   u32_t rttest; /* RTT estimate in 500ms ticks */
 331   u32_t rtseq;  /* sequence number being timed */
 332   s16_t sa, sv; /* @todo document this */
 333
 334   s16_t rto;    /* retransmission time-out */
 335   u8_t nrtx;    /* number of retransmissions */
 336
 337   /* fast retransmit/recovery */
 338   u32_t lastack; /* Highest acknowledged seqno. */
 339   u8_t dupacks;
 340
 341   /* congestion avoidance/control variables */
 342   u16_t cwnd;
 343   u16_t ssthresh;
 344
 345   /* sender variables */
 346   u32_t snd_nxt;   /* next new seqno to be sent */
 347   u16_t snd_wnd;   /* sender window */
 348   u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
 349                              window update. */
 350   u32_t snd_lbb;       /* Sequence number of next byte to be buffered. */
 351
 352   u16_t acked;
 353
 354   u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
 355 #define TCP_SNDQUEUELEN_OVERFLOW (0xffff-3)
 356   u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
 357
 358
 359   /* These are ordered by sequence number: */
 360   struct tcp_seg *unsent;   /* Unsent (queued) segments. */
 361   struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
 362 #if TCP_QUEUE_OOSEQ
 363   struct tcp_seg *ooseq;    /* Received out of sequence segments. */
 364 #endif /* TCP_QUEUE_OOSEQ */
 365
 366   struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
 367
 368 #if LWIP_CALLBACK_API
 369   /* Function to be called when more send buffer space is available.
 370    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 371    * @param pcb the tcp_pcb which has send buffer space available
 372    * @param space the amount of bytes available
 373    * @return ERR_OK: try to send some data by calling tcp_output
 374    */
 375   err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);
 376
 377   /* Function to be called when (in-sequence) data has arrived.
 378    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 379    * @param pcb the tcp_pcb for which data has arrived
 380    * @param p the packet buffer which arrived
 381    * @param err an error argument (TODO: that is current always ERR_OK?)
 382    * @return ERR_OK: try to send some data by calling tcp_output
 383    */
 384   err_t (* recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
 385
 386   /* Function to be called when a connection has been set up.
 387    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 388    * @param pcb the tcp_pcb that now is connected
 389    * @param err an error argument (TODO: that is current always ERR_OK?)
 390    * @return value is currently ignored
 391    */
 392   err_t (* connected)(void *arg, struct tcp_pcb *pcb, err_t err);
 393
 394   /* Function which is called periodically.
 395    * The period can be adjusted in multiples of the TCP slow timer interval
 396    * by changing tcp_pcb.polltmr.
 397    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 398    * @param pcb the tcp_pcb to poll for
 399    * @return ERR_OK: try to send some data by calling tcp_output
 400    */
 401   err_t (* poll)(void *arg, struct tcp_pcb *pcb);
 402
 403   /* Function to be called whenever a fatal error occurs.
 404    * There is no pcb parameter since most of the times, the pcb is
 405    * already deallocated (or there is no pcb) when this function is called.
 406    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 407    * @param err an indication why the error callback is called:
 408    *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
 409    *            ERR_RST: the connection was reset by the remote host
 410    */
 411   void (* errf)(void *arg, err_t err);
 412 #endif /* LWIP_CALLBACK_API */
 413
 414 #if LWIP_TCP_TIMESTAMPS
 415   u32_t ts_lastacksent;
 416   u32_t ts_recent;
 417 #endif /* LWIP_TCP_TIMESTAMPS */
 418
 419   /* idle time before KEEPALIVE is sent */
 420   u32_t keep_idle;
 421 #if LWIP_TCP_KEEPALIVE
 422   u32_t keep_intvl;
 423   u32_t keep_cnt;
 424 #endif /* LWIP_TCP_KEEPALIVE */
 425
 426   /* Persist timer counter */
 427   u32_t persist_cnt;
 428   /* Persist timer back-off */
 429   u8_t persist_backoff;
 430
 431   /* KEEPALIVE counter */
 432   u8_t keep_cnt_sent;
 433 };
 434
 435 struct tcp_pcb_listen {
 436 /* Common members of all PCB types */
 437   IP_PCB;
 438 /* Protocol specific PCB members */
 439   TCP_PCB_COMMON(struct tcp_pcb_listen);
 440
 441 #if TCP_LISTEN_BACKLOG
 442   u8_t backlog;
 443   u8_t accepts_pending;
 444 #endif /* TCP_LISTEN_BACKLOG */
 445 };
 446
 447 #if LWIP_EVENT_API
 448
 449 enum lwip_event {
 450   LWIP_EVENT_ACCEPT,
 451   LWIP_EVENT_SENT,
 452   LWIP_EVENT_RECV,
 453   LWIP_EVENT_CONNECTED,
 454   LWIP_EVENT_POLL,
 455   LWIP_EVENT_ERR
 456 };
 457
 458 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
 459          enum lwip_event,
 460          struct pbuf *p,
 461          u16_t size,
 462          err_t err);
 463
 464 #define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 465                 LWIP_EVENT_ACCEPT, NULL, 0, err)
 466 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 467                    LWIP_EVENT_SENT, NULL, space, ERR_OK)
 468 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 469                 LWIP_EVENT_RECV, (p), 0, (err))
 470 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 471                 LWIP_EVENT_CONNECTED, NULL, 0, (err))
 472 #define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
 473                 LWIP_EVENT_POLL, NULL, 0, ERR_OK)
 474 #define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
 475                 LWIP_EVENT_ERR, NULL, 0, (err))
 476 #else /* LWIP_EVENT_API */
 477
 478 #define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
 479   do {                                                         \
 480     if((pcb)->accept != NULL)                                  \
 481       (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
 482     else (ret) = ERR_OK;                                       \
 483   } while (0)
 484
 485 #define TCP_EVENT_SENT(pcb,space,ret)                          \
 486   do {                                                         \
 487     if((pcb)->sent != NULL)                                    \
 488       (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
 489     else (ret) = ERR_OK;                                       \
 490   } while (0)
 491
 492 #define TCP_EVENT_RECV(pcb,p,err,ret)                           \
 493   do {                                                          \
 494     if((pcb)->recv != NULL) {                                   \
 495       (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); \
 496     } else {                                                    \
 497       (ret) = tcp_recv_null(NULL, (pcb), (p), (err));           \
 498     }                                                           \
 499   } while (0)
 500
 501 #define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
 502   do {                                                           \
 503     if((pcb)->connected != NULL)                                 \
 504       (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
 505     else (ret) = ERR_OK;                                         \
 506   } while (0)
 507
 508 #define TCP_EVENT_POLL(pcb,ret)                                \
 509   do {                                                         \
 510     if((pcb)->poll != NULL)                                    \
 511       (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
 512     else (ret) = ERR_OK;                                       \
 513   } while (0)
 514
 515 #define TCP_EVENT_ERR(errf,arg,err)                            \
 516   do {                                                         \
 517     if((errf) != NULL)                                         \
 518       (errf)((arg),(err));                                     \
 519   } while (0)
 520
 521 #endif /* LWIP_EVENT_API */
 522
 523 /* This structure represents a TCP segment on the unsent and unacked queues */
 524 struct tcp_seg {
 525   struct tcp_seg *next;    /* used when putting segements on a queue */
 526   struct pbuf *p;          /* buffer containing data + TCP header */
 527   void *dataptr;           /* pointer to the TCP data in the pbuf */
 528   u16_t len;               /* the TCP length of this segment */
 529   u8_t  flags;
 530 #define TF_SEG_OPTS_MSS   (u8_t)0x01U   /* Include MSS option. */
 531 #define TF_SEG_OPTS_TS    (u8_t)0x02U   /* Include timestamp option. */
 532   struct tcp_hdr *tcphdr;  /* the TCP header */
 533 };
 534
 535 #define LWIP_TCP_OPT_LENGTH(flags)              \
 536   (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
 537   (flags & TF_SEG_OPTS_TS  ? 12 : 0)
 538
 539 /** This returns a TCP header option for MSS in an u32_t */
 540 #define TCP_BUILD_MSS_OPTION(x) (x) = htonl(((u32_t)2 << 24) |          \
 541                                             ((u32_t)4 << 16) |          \
 542                                             (((u32_t)TCP_MSS / 256) << 8) | \
 543                                             (TCP_MSS & 255))
 544
 545 /* Internal functions and global variables: */
 546 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
 547 void tcp_pcb_purge(struct tcp_pcb *pcb);
 548 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);
 549
 550 u8_t tcp_segs_free(struct tcp_seg *seg);
 551 u8_t tcp_seg_free(struct tcp_seg *seg);
 552 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);
 553
 554 #define tcp_ack(pcb)                               \
 555   do {                                             \
 556     if((pcb)->flags & TF_ACK_DELAY) {              \
 557       (pcb)->flags &= ~TF_ACK_DELAY;               \
 558       (pcb)->flags |= TF_ACK_NOW;                  \
 559       tcp_output(pcb);                             \
 560     }                                              \
 561     else {                                         \
 562       (pcb)->flags |= TF_ACK_DELAY;                \
 563     }                                              \
 564   } while (0)
 565
 566 #define tcp_ack_now(pcb)                           \
 567   do {                                             \
 568     (pcb)->flags |= TF_ACK_NOW;                    \
 569     tcp_output(pcb);                               \
 570   } while (0)
 571
 572 err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);
 573 err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,
 574                   u8_t flags, u8_t apiflags, u8_t optflags);
 575
 576 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);
 577
 578 void tcp_rst(u32_t seqno, u32_t ackno,
 579        struct ip_addr *local_ip, struct ip_addr *remote_ip,
 580        u16_t local_port, u16_t remote_port);
 581
 582 u32_t tcp_next_iss(void);
 583
 584 void tcp_keepalive(struct tcp_pcb *pcb);
 585 void tcp_zero_window_probe(struct tcp_pcb *pcb);
 586
 587 #if TCP_CALCULATE_EFF_SEND_MSS
 588 u16_t tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr);
 589 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
 590
 591 #if LWIP_CALLBACK_API
 592 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
 593 #endif /* LWIP_CALLBACK_API */
 594
 595 extern struct tcp_pcb *tcp_input_pcb;
 596 extern u32_t tcp_ticks;
 597
 598 const char* tcp_debug_state_str(enum tcp_state s);
 599 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
 600 void tcp_debug_print(struct tcp_hdr *tcphdr);
 601 void tcp_debug_print_flags(u8_t flags);
 602 void tcp_debug_print_state(enum tcp_state s);
 603 void tcp_debug_print_pcbs(void);
 604 s16_t tcp_pcbs_sane(void);
 605 #else
 606 #  define tcp_debug_print(tcphdr)
 607 #  define tcp_debug_print_flags(flags)
 608 #  define tcp_debug_print_state(s)
 609 #  define tcp_debug_print_pcbs()
 610 #  define tcp_pcbs_sane() 1
 611 #endif /* TCP_DEBUG */
 612
 613 #if NO_SYS
 614 #define tcp_timer_needed()
 615 #else
 616 void tcp_timer_needed(void);
 617 #endif
 618
 619 /* The TCP PCB lists. */
 620 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
 621   struct tcp_pcb_listen *listen_pcbs;
 622   struct tcp_pcb *pcbs;
 623 };
 624 extern union tcp_listen_pcbs_t tcp_listen_pcbs;
 625 extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
 626               state in which they accept or send
 627               data. */
 628 extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */
 629
 630 extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */
 631
 632 /* Axioms about the above lists:
 633    1) Every TCP PCB that is not CLOSED is in one of the lists.
 634    2) A PCB is only in one of the lists.
 635    3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
 636    4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
 637 */
 638
 639 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
 640    with a PCB list or removes a PCB from a list, respectively. */
 641 #if 0
 642 #define TCP_REG(pcbs, npcb) do {\
 643                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
 644                             for(tcp_tmp_pcb = *pcbs; \
 645           tcp_tmp_pcb != NULL; \
 646         tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 647                                 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
 648                             } \
 649                             LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
 650                             npcb->next = *pcbs; \
 651                             LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
 652                             *(pcbs) = npcb; \
 653                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 654               tcp_timer_needed(); \
 655                             } while(0)
 656 #define TCP_RMV(pcbs, npcb) do { \
 657                             LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
 658                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
 659                             if(*pcbs == npcb) { \
 660                                *pcbs = (*pcbs)->next; \
 661                             } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
 662                                if(tcp_tmp_pcb->next == npcb) { \
 663                                   tcp_tmp_pcb->next = npcb->next; \
 664                                   break; \
 665                                } \
 666                             } \
 667                             npcb->next = NULL; \
 668                             LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
 669                             LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
 670                             } while(0)
 671
 672 #else /* LWIP_DEBUG */
 673
 674 #define TCP_REG(pcbs, npcb)                        \
 675   do {                                             \
 676     npcb->next = *pcbs;                            \
 677     *(pcbs) = npcb;                                \
 678     tcp_timer_needed();                            \
 679   } while (0)
 680
 681 #define TCP_RMV(pcbs, npcb)                        \
 682   do {                                             \
 683     if(*(pcbs) == npcb) {                          \
 684       (*(pcbs)) = (*pcbs)->next;                   \
 685     }                                              \
 686     else {                                         \
 687       for(tcp_tmp_pcb = *pcbs;                                         \
 688           tcp_tmp_pcb != NULL;                                         \
 689           tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
 690         if(tcp_tmp_pcb->next == npcb) {   \
 691           tcp_tmp_pcb->next = npcb->next;          \
 692           break;                                   \
 693         }                                          \
 694       }                                            \
 695     }                                              \
 696     npcb->next = NULL;                             \
 697   } while(0)
 698
 699 #endif /* LWIP_DEBUG */
 700
 701 #ifdef __cplusplus
 702 }
 703 #endif
 704
 705 #endif /* LWIP_TCP */
 706
 707 #endif /* __LWIP_TCP_H__ */