lib/drivers/lwip/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 /** Function prototype for tcp accept callback functions. Called when a new
  53  * connection can be accepted on a listening pcb.
  54  *
  55  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
  56  * @param newpcb The new connection pcb
  57  * @param err An error code if there has been an error accepting.
  58  *            Only return ERR_ABRT if you have called tcp_abort from within the
  59  *            callback function!
  60  */
  61 typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err);
  62
  63 /** Function prototype for tcp receive callback functions. Called when data has
  64  * been received.
  65  *
  66  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
  67  * @param tpcb The connection pcb which received data
  68  * @param p The received data (or NULL when the connection has been closed!)
  69  * @param err An error code if there has been an error receiving
  70  *            Only return ERR_ABRT if you have called tcp_abort from within the
  71  *            callback function!
  72  */
  73 typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb,
  74                              struct pbuf *p, err_t err);
  75
  76 /** Function prototype for tcp sent callback functions. Called when sent data has
  77  * been acknowledged by the remote side. Use it to free corresponding resources.
  78  * This also means that the pcb has now space available to send new data.
  79  *
  80  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
  81  * @param tpcb The connection pcb for which data has been acknowledged
  82  * @param len The amount of bytes acknowledged
  83  * @return ERR_OK: try to send some data by calling tcp_output
  84  *            Only return ERR_ABRT if you have called tcp_abort from within the
  85  *            callback function!
  86  */
  87 typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb,
  88                               u16_t len);
  89
  90 /** Function prototype for tcp poll callback functions. Called periodically as
  91  * specified by @see tcp_poll.
  92  *
  93  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
  94  * @param tpcb tcp pcb
  95  * @return ERR_OK: try to send some data by calling tcp_output
  96  *            Only return ERR_ABRT if you have called tcp_abort from within the
  97  *            callback function!
  98  */
  99 typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb);
 100
 101 /** Function prototype for tcp error callback functions. Called when the pcb
 102  * receives a RST or is unexpectedly closed for any other reason.
 103  *
 104  * @note The corresponding pcb is already freed when this callback is called!
 105  *
 106  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
 107  * @param err Error code to indicate why the pcb has been closed
 108  *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
 109  *            ERR_RST: the connection was reset by the remote host
 110  */
 111 typedef void  (*tcp_err_fn)(void *arg, err_t err);
 112
 113 /** Function prototype for tcp connected callback functions. Called when a pcb
 114  * is connected to the remote side after initiating a connection attempt by
 115  * calling tcp_connect().
 116  *
 117  * @param arg Additional argument to pass to the callback function (@see tcp_arg())
 118  * @param tpcb The connection pcb which is connected
 119  * @param err An unused error code, always ERR_OK currently ;-) TODO!
 120  *            Only return ERR_ABRT if you have called tcp_abort from within the
 121  *            callback function!
 122  *
 123  * @note When a connection attempt fails, the error callback is currently called!
 124  */
 125 typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err);
 126
 127 enum tcp_state {
 128   CLOSED      = 0,
 129   LISTEN      = 1,
 130   SYN_SENT    = 2,
 131   SYN_RCVD    = 3,
 132   ESTABLISHED = 4,
 133   FIN_WAIT_1  = 5,
 134   FIN_WAIT_2  = 6,
 135   CLOSE_WAIT  = 7,
 136   CLOSING     = 8,
 137   LAST_ACK    = 9,
 138   TIME_WAIT   = 10
 139 };
 140
 141 #if LWIP_CALLBACK_API
 142   /* Function to call when a listener has been connected.
 143    * @param arg user-supplied argument (tcp_pcb.callback_arg)
 144    * @param pcb a new tcp_pcb that now is connected
 145    * @param err an error argument (TODO: that is current always ERR_OK?)
 146    * @return ERR_OK: accept the new connection,
 147    *                 any other err_t abortsthe new connection
 148    */
 149 #define DEF_ACCEPT_CALLBACK  tcp_accept_fn accept;
 150 #else /* LWIP_CALLBACK_API */
 151 #define DEF_ACCEPT_CALLBACK
 152 #endif /* LWIP_CALLBACK_API */
 153
 154 /**
 155  * members common to struct tcp_pcb and struct tcp_listen_pcb
 156  */
 157 #define TCP_PCB_COMMON(type) \
 158   type *next; /* for the linked list */ \
 159   enum tcp_state state; /* TCP state */ \
 160   u8_t prio; \
 161   void *callback_arg; \
 162   /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
 163   DEF_ACCEPT_CALLBACK \
 164   /* ports are in host byte order */ \
 165   u16_t local_port
 166
 167
 168 /* the TCP protocol control block */
 169 struct tcp_pcb {
 170 /** common PCB members */
 171   IP_PCB;
 172 /** protocol specific PCB members */
 173   TCP_PCB_COMMON(struct tcp_pcb);
 174
 175   /* ports are in host byte order */
 176   u16_t remote_port;
 177
 178   u8_t flags;
 179 #define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
 180 #define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
 181 #define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
 182 #define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
 183 #define TF_RXCLOSED    ((u8_t)0x10U)   /* rx closed by tcp_shutdown */
 184 #define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
 185 #define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
 186 #define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
 187
 188   /* the rest of the fields are in host byte order
 189      as we have to do some math with them */
 190   /* receiver variables */
 191   u32_t rcv_nxt;   /* next seqno expected */
 192   u16_t rcv_wnd;   /* receiver window available */
 193   u16_t rcv_ann_wnd; /* receiver window to announce */
 194   u32_t rcv_ann_right_edge; /* announced right edge of window */
 195
 196   /* Timers */
 197   u32_t tmr;
 198   u8_t polltmr, pollinterval;
 199
 200   /* Retransmission timer. */
 201   s16_t rtime;
 202
 203   u16_t mss;   /* maximum segment size */
 204
 205   /* RTT (round trip time) estimation variables */
 206   u32_t rttest; /* RTT estimate in 500ms ticks */
 207   u32_t rtseq;  /* sequence number being timed */
 208   s16_t sa, sv; /* @todo document this */
 209
 210   s16_t rto;    /* retransmission time-out */
 211   u8_t nrtx;    /* number of retransmissions */
 212
 213   /* fast retransmit/recovery */
 214   u32_t lastack; /* Highest acknowledged seqno. */
 215   u8_t dupacks;
 216
 217   /* congestion avoidance/control variables */
 218   u16_t cwnd;
 219   u16_t ssthresh;
 220
 221   /* sender variables */
 222   u32_t snd_nxt;   /* next new seqno to be sent */
 223   u16_t snd_wnd;   /* sender window */
 224   u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
 225                              window update. */
 226   u32_t snd_lbb;       /* Sequence number of next byte to be buffered. */
 227
 228   u16_t acked;
 229
 230   u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
 231 #define TCP_SNDQUEUELEN_OVERFLOW (0xffff-3)
 232   u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
 233
 234 #if TCP_OVERSIZE
 235   /* Extra bytes available at the end of the last pbuf in unsent. */
 236   u16_t unsent_oversize;
 237 #endif /* TCP_OVERSIZE */
 238
 239   /* These are ordered by sequence number: */
 240   struct tcp_seg *unsent;   /* Unsent (queued) segments. */
 241   struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
 242 #if TCP_QUEUE_OOSEQ
 243   struct tcp_seg *ooseq;    /* Received out of sequence segments. */
 244 #endif /* TCP_QUEUE_OOSEQ */
 245
 246   struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
 247
 248 #if LWIP_CALLBACK_API
 249   /* Function to be called when more send buffer space is available. */
 250   tcp_sent_fn sent;
 251   /* Function to be called when (in-sequence) data has arrived. */
 252   tcp_recv_fn recv;
 253   /* Function to be called when a connection has been set up. */
 254   tcp_connected_fn connected;
 255   /* Function which is called periodically. */
 256   tcp_poll_fn poll;
 257   /* Function to be called whenever a fatal error occurs. */
 258   tcp_err_fn errf;
 259 #endif /* LWIP_CALLBACK_API */
 260
 261 #if LWIP_TCP_TIMESTAMPS
 262   u32_t ts_lastacksent;
 263   u32_t ts_recent;
 264 #endif /* LWIP_TCP_TIMESTAMPS */
 265
 266   /* idle time before KEEPALIVE is sent */
 267   u32_t keep_idle;
 268 #if LWIP_TCP_KEEPALIVE
 269   u32_t keep_intvl;
 270   u32_t keep_cnt;
 271 #endif /* LWIP_TCP_KEEPALIVE */
 272
 273   /* Persist timer counter */
 274   u32_t persist_cnt;
 275   /* Persist timer back-off */
 276   u8_t persist_backoff;
 277
 278   /* KEEPALIVE counter */
 279   u8_t keep_cnt_sent;
 280   u16_t identifier;
 281 };
 282
 283 struct tcp_pcb_listen {
 284 /* Common members of all PCB types */
 285   IP_PCB;
 286 /* Protocol specific PCB members */
 287   TCP_PCB_COMMON(struct tcp_pcb_listen);
 288
 289 #if TCP_LISTEN_BACKLOG
 290   u8_t backlog;
 291   u8_t accepts_pending;
 292 #endif /* TCP_LISTEN_BACKLOG */
 293 };
 294
 295 #if LWIP_EVENT_API
 296
 297 enum lwip_event {
 298   LWIP_EVENT_ACCEPT,
 299   LWIP_EVENT_SENT,
 300   LWIP_EVENT_RECV,
 301   LWIP_EVENT_CONNECTED,
 302   LWIP_EVENT_POLL,
 303   LWIP_EVENT_ERR
 304 };
 305
 306 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
 307          enum lwip_event,
 308          struct pbuf *p,
 309          u16_t size,
 310          err_t err);
 311
 312 #endif /* LWIP_EVENT_API */
 313
 314 /* Application program's interface: */
 315 struct tcp_pcb * tcp_new     (void);
 316
 317 void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
 318 void             tcp_accept  (struct tcp_pcb *pcb, tcp_accept_fn accept);
 319 void             tcp_recv    (struct tcp_pcb *pcb, tcp_recv_fn recv);
 320 void             tcp_sent    (struct tcp_pcb *pcb, tcp_sent_fn sent);
 321 void             tcp_poll    (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval);
 322 void             tcp_err     (struct tcp_pcb *pcb, tcp_err_fn err);
 323
 324 #define          tcp_mss(pcb)             (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12)  : (pcb)->mss)
 325 #define          tcp_sndbuf(pcb)          ((pcb)->snd_buf)
 326 #define          tcp_sndqueuelen(pcb)     ((pcb)->snd_queuelen)
 327 #define          tcp_nagle_disable(pcb)   ((pcb)->flags |= TF_NODELAY)
 328 #define          tcp_nagle_enable(pcb)    ((pcb)->flags &= ~TF_NODELAY)
 329 #define          tcp_nagle_disabled(pcb)  (((pcb)->flags & TF_NODELAY) != 0)
 330
 331 #if TCP_LISTEN_BACKLOG
 332 #define          tcp_accepted(pcb) do { \
 333   LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
 334   (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0)
 335 #else  /* TCP_LISTEN_BACKLOG */
 336 #define          tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \
 337                                                pcb->state == LISTEN)
 338 #endif /* TCP_LISTEN_BACKLOG */
 339
 340 void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
 341 err_t            tcp_bind    (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
 342                               u16_t port);
 343 err_t            tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
 344                               u16_t port, tcp_connected_fn connected);
 345
 346 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
 347 #define          tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
 348
 349 void             tcp_abort (struct tcp_pcb *pcb);
 350 err_t            tcp_close   (struct tcp_pcb *pcb);
 351 err_t            tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx);
 352
 353 /* Flags for "apiflags" parameter in tcp_write */
 354 #define TCP_WRITE_FLAG_COPY 0x01
 355 #define TCP_WRITE_FLAG_MORE 0x02
 356
 357 err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
 358                               u8_t apiflags);
 359
 360 void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
 361
 362 #define TCP_PRIO_MIN    1
 363 #define TCP_PRIO_NORMAL 64
 364 #define TCP_PRIO_MAX    127
 365
 366 err_t            tcp_output  (struct tcp_pcb *pcb);
 367
 368
 369 const char* tcp_debug_state_str(enum tcp_state s);
 370
 371
 372 #ifdef __cplusplus
 373 }
 374 #endif
 375
 376 #endif /* LWIP_TCP */
 377
 378 #endif /* __LWIP_TCP_H__ */