1/** 2 * @file 3 * TCP API (to be used from TCPIP thread)\n 4 * See also @ref tcp_raw 5 */ 6 7/* 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without modification, 12 * are permitted provided that the following conditions are met: 13 * 14 * 1. Redistributions of source code must retain the above copyright notice, 15 * this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright notice, 17 * this list of conditions and the following disclaimer in the documentation 18 * and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 25 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 27 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 30 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 31 * OF SUCH DAMAGE. 32 * 33 * This file is part of the lwIP TCP/IP stack. 34 * 35 * Author: Adam Dunkels <adam@sics.se> 36 * 37 */ 38#ifndef LWIP_HDR_TCP_H 39#define LWIP_HDR_TCP_H 40 41#include "lwip/opt.h" 42 43#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ 44 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 53#ifdef __cplusplus 54extern "C" { 55#endif 56 57struct tcp_pcb; 58 59/** Function prototype for tcp accept callback functions. Called when a new 60 * connection can be accepted on a listening pcb. 61 * 62 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 63 * @param newpcb The new connection pcb 64 * @param err An error code if there has been an error accepting. 65 * Only return ERR_ABRT if you have called tcp_abort from within the 66 * callback function! 67 */ 68typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err); 69 70/** Function prototype for tcp receive callback functions. Called when data has 71 * been received. 72 * 73 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 74 * @param tpcb The connection pcb which received data 75 * @param p The received data (or NULL when the connection has been closed!) 76 * @param err An error code if there has been an error receiving 77 * Only return ERR_ABRT if you have called tcp_abort from within the 78 * callback function! 79 */ 80typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb, 81 struct pbuf *p, err_t err); 82 83/** Function prototype for tcp sent callback functions. Called when sent data has 84 * been acknowledged by the remote side. Use it to free corresponding resources. 85 * This also means that the pcb has now space available to send new data. 86 * 87 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 88 * @param tpcb The connection pcb for which data has been acknowledged 89 * @param len The amount of bytes acknowledged 90 * @return ERR_OK: try to send some data by calling tcp_output 91 * Only return ERR_ABRT if you have called tcp_abort from within the 92 * callback function! 93 */ 94typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb, 95 u16_t len); 96 97/** Function prototype for tcp poll callback functions. Called periodically as 98 * specified by @see tcp_poll. 99 * 100 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 101 * @param tpcb tcp pcb 102 * @return ERR_OK: try to send some data by calling tcp_output 103 * Only return ERR_ABRT if you have called tcp_abort from within the 104 * callback function! 105 */ 106typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb); 107 108/** Function prototype for tcp error callback functions. Called when the pcb 109 * receives a RST or is unexpectedly closed for any other reason. 110 * 111 * @note The corresponding pcb is already freed when this callback is called! 112 * 113 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 114 * @param err Error code to indicate why the pcb has been closed 115 * ERR_ABRT: aborted through tcp_abort or by a TCP timer 116 * ERR_RST: the connection was reset by the remote host 117 */ 118typedef void (*tcp_err_fn)(void *arg, err_t err); 119 120/** Function prototype for tcp connected callback functions. Called when a pcb 121 * is connected to the remote side after initiating a connection attempt by 122 * calling tcp_connect(). 123 * 124 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 125 * @param tpcb The connection pcb which is connected 126 * @param err An unused error code, always ERR_OK currently ;-) @todo! 127 * Only return ERR_ABRT if you have called tcp_abort from within the 128 * callback function! 129 * 130 * @note When a connection attempt fails, the error callback is currently called! 131 */ 132typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err); 133 134#if LWIP_WND_SCALE 135#define RCV_WND_SCALE(pcb, wnd) (((wnd) >> (pcb)->rcv_scale)) 136#define SND_WND_SCALE(pcb, wnd) (((wnd) << (pcb)->snd_scale)) 137#define TCPWND16(x) ((u16_t)LWIP_MIN((x), 0xFFFF)) 138#define TCP_WND_MAX(pcb) ((tcpwnd_size_t)(((pcb)->flags & TF_WND_SCALE) ? TCP_WND : TCPWND16(TCP_WND))) 139typedef u32_t tcpwnd_size_t; 140#else 141#define RCV_WND_SCALE(pcb, wnd) (wnd) 142#define SND_WND_SCALE(pcb, wnd) (wnd) 143#define TCPWND16(x) (x) 144#define TCP_WND_MAX(pcb) TCP_WND 145typedef u16_t tcpwnd_size_t; 146#endif 147 148#if LWIP_WND_SCALE || TCP_LISTEN_BACKLOG || LWIP_TCP_TIMESTAMPS 149typedef u16_t tcpflags_t; 150#else 151typedef u8_t tcpflags_t; 152#endif 153 154enum tcp_state { 155 CLOSED = 0, 156 LISTEN = 1, 157 SYN_SENT = 2, 158 SYN_RCVD = 3, 159 ESTABLISHED = 4, 160 FIN_WAIT_1 = 5, 161 FIN_WAIT_2 = 6, 162 CLOSE_WAIT = 7, 163 CLOSING = 8, 164 LAST_ACK = 9, 165 TIME_WAIT = 10 166}; 167 168/** 169 * members common to struct tcp_pcb and struct tcp_listen_pcb 170 */ 171#define TCP_PCB_COMMON(type) \ 172 type *next; /* for the linked list */ \ 173 void *callback_arg; \ 174 enum tcp_state state; /* TCP state */ \ 175 u8_t prio; \ 176 /* ports are in host byte order */ \ 177 u16_t local_port 178 179 180/** the TCP protocol control block for listening pcbs */ 181struct tcp_pcb_listen { 182/** Common members of all PCB types */ 183 IP_PCB; 184/** Protocol specific PCB members */ 185 TCP_PCB_COMMON(struct tcp_pcb_listen); 186 187#if LWIP_CALLBACK_API 188 /* Function to call when a listener has been connected. */ 189 tcp_accept_fn accept; 190#endif /* LWIP_CALLBACK_API */ 191 192#if TCP_LISTEN_BACKLOG 193 u8_t backlog; 194 u8_t accepts_pending; 195#endif /* TCP_LISTEN_BACKLOG */ 196}; 197 198 199/** the TCP protocol control block */ 200struct tcp_pcb { 201/** common PCB members */ 202 IP_PCB; 203/** protocol specific PCB members */ 204 TCP_PCB_COMMON(struct tcp_pcb); 205 206 /* ports are in host byte order */ 207 u16_t remote_port; 208 209 tcpflags_t flags; 210#define TF_ACK_DELAY 0x01U /* Delayed ACK. */ 211#define TF_ACK_NOW 0x02U /* Immediate ACK. */ 212#define TF_INFR 0x04U /* In fast recovery. */ 213#define TF_CLOSEPEND 0x08U /* If this is set, tcp_close failed to enqueue the FIN (retried in tcp_tmr) */ 214#define TF_RXCLOSED 0x10U /* rx closed by tcp_shutdown */ 215#define TF_FIN 0x20U /* Connection was closed locally (FIN segment enqueued). */ 216#define TF_NODELAY 0x40U /* Disable Nagle algorithm */ 217#define TF_NAGLEMEMERR 0x80U /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */ 218#if LWIP_WND_SCALE 219#define TF_WND_SCALE 0x0100U /* Window Scale option enabled */ 220#endif 221#if TCP_LISTEN_BACKLOG 222#define TF_BACKLOGPEND 0x0200U /* If this is set, a connection pcb has increased the backlog on its listener */ 223#endif 224#if LWIP_TCP_TIMESTAMPS 225#define TF_TIMESTAMP 0x0400U /* Timestamp option enabled */ 226#endif 227 228 /* the rest of the fields are in host byte order 229 as we have to do some math with them */ 230 231 /* Timers */ 232 u8_t polltmr, pollinterval; 233 u8_t last_timer; 234 u32_t tmr; 235 236 /* receiver variables */ 237 u32_t rcv_nxt; /* next seqno expected */ 238 tcpwnd_size_t rcv_wnd; /* receiver window available */ 239 tcpwnd_size_t rcv_ann_wnd; /* receiver window to announce */ 240 u32_t rcv_ann_right_edge; /* announced right edge of window */ 241 242 /* Retransmission timer. */ 243 s16_t rtime; 244 245 u16_t mss; /* maximum segment size */ 246 247 /* RTT (round trip time) estimation variables */ 248 u32_t rttest; /* RTT estimate in 500ms ticks */ 249 u32_t rtseq; /* sequence number being timed */ 250 s16_t sa, sv; /* @todo document this */ 251 252 s16_t rto; /* retransmission time-out */ 253 u8_t nrtx; /* number of retransmissions */ 254 255 /* fast retransmit/recovery */ 256 u8_t dupacks; 257 u32_t lastack; /* Highest acknowledged seqno. */ 258 259 /* congestion avoidance/control variables */ 260 tcpwnd_size_t cwnd; 261 tcpwnd_size_t ssthresh; 262 263 /* sender variables */ 264 u32_t snd_nxt; /* next new seqno to be sent */ 265 u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last 266 window update. */ 267 u32_t snd_lbb; /* Sequence number of next byte to be buffered. */ 268 tcpwnd_size_t snd_wnd; /* sender window */ 269 tcpwnd_size_t snd_wnd_max; /* the maximum sender window announced by the remote host */ 270 271 tcpwnd_size_t snd_buf; /* Available buffer space for sending (in bytes). */ 272#define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3) 273 u16_t snd_queuelen; /* Number of pbufs currently in the send buffer. */ 274 275#if TCP_OVERSIZE 276 /* Extra bytes available at the end of the last pbuf in unsent. */ 277 u16_t unsent_oversize; 278#endif /* TCP_OVERSIZE */ 279 280 /* These are ordered by sequence number: */ 281 struct tcp_seg *unsent; /* Unsent (queued) segments. */ 282 struct tcp_seg *unacked; /* Sent but unacknowledged segments. */ 283#if TCP_QUEUE_OOSEQ 284 struct tcp_seg *ooseq; /* Received out of sequence segments. */ 285#endif /* TCP_QUEUE_OOSEQ */ 286 287 struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */ 288 289#if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG 290 struct tcp_pcb_listen* listener; 291#endif /* LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG */ 292 293#if LWIP_CALLBACK_API 294 /* Function to be called when more send buffer space is available. */ 295 tcp_sent_fn sent; 296 /* Function to be called when (in-sequence) data has arrived. */ 297 tcp_recv_fn recv; 298 /* Function to be called when a connection has been set up. */ 299 tcp_connected_fn connected; 300 /* Function which is called periodically. */ 301 tcp_poll_fn poll; 302 /* Function to be called whenever a fatal error occurs. */ 303 tcp_err_fn errf; 304#endif /* LWIP_CALLBACK_API */ 305 306#if LWIP_TCP_TIMESTAMPS 307 u32_t ts_lastacksent; 308 u32_t ts_recent; 309#endif /* LWIP_TCP_TIMESTAMPS */ 310 311 /* idle time before KEEPALIVE is sent */ 312 u32_t keep_idle; 313#if LWIP_TCP_KEEPALIVE 314 u32_t keep_intvl; 315 u32_t keep_cnt; 316#endif /* LWIP_TCP_KEEPALIVE */ 317 318 /* Persist timer counter */ 319 u8_t persist_cnt; 320 /* Persist timer back-off */ 321 u8_t persist_backoff; 322 323 /* KEEPALIVE counter */ 324 u8_t keep_cnt_sent; 325 326#if LWIP_WND_SCALE 327 u8_t snd_scale; 328 u8_t rcv_scale; 329#endif 330}; 331 332#if LWIP_EVENT_API 333 334enum lwip_event { 335 LWIP_EVENT_ACCEPT, 336 LWIP_EVENT_SENT, 337 LWIP_EVENT_RECV, 338 LWIP_EVENT_CONNECTED, 339 LWIP_EVENT_POLL, 340 LWIP_EVENT_ERR 341}; 342 343err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb, 344 enum lwip_event, 345 struct pbuf *p, 346 u16_t size, 347 err_t err); 348 349#endif /* LWIP_EVENT_API */ 350 351/* Application program's interface: */ 352struct tcp_pcb * tcp_new (void); 353struct tcp_pcb * tcp_new_ip_type (u8_t type); 354 355void tcp_arg (struct tcp_pcb *pcb, void *arg); 356#if LWIP_CALLBACK_API 357void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv); 358void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent); 359void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err); 360void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept); 361#endif /* LWIP_CALLBACK_API */ 362void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval); 363 364#if LWIP_TCP_TIMESTAMPS 365#define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss) 366#else /* LWIP_TCP_TIMESTAMPS */ 367#define tcp_mss(pcb) ((pcb)->mss) 368#endif /* LWIP_TCP_TIMESTAMPS */ 369#define tcp_sndbuf(pcb) (TCPWND16((pcb)->snd_buf)) 370#define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen) 371/** @ingroup tcp_raw */ 372#define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY) 373/** @ingroup tcp_raw */ 374#define tcp_nagle_enable(pcb) ((pcb)->flags = (tcpflags_t)((pcb)->flags & ~TF_NODELAY)) 375/** @ingroup tcp_raw */ 376#define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0) 377 378#if TCP_LISTEN_BACKLOG 379#define tcp_backlog_set(pcb, new_backlog) do { \ 380 LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", (pcb)->state == LISTEN); \ 381 ((struct tcp_pcb_listen *)(pcb))->backlog = ((new_backlog) ? (new_backlog) : 1); } while(0) 382void tcp_backlog_delayed(struct tcp_pcb* pcb); 383void tcp_backlog_accepted(struct tcp_pcb* pcb); 384#else /* TCP_LISTEN_BACKLOG */ 385#define tcp_backlog_set(pcb, new_backlog) 386#define tcp_backlog_delayed(pcb) 387#define tcp_backlog_accepted(pcb) 388#endif /* TCP_LISTEN_BACKLOG */ 389#define tcp_accepted(pcb) /* compatibility define, not needed any more */ 390 391void tcp_recved (struct tcp_pcb *pcb, u16_t len); 392err_t tcp_bind (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, 393 u16_t port); 394err_t tcp_connect (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, 395 u16_t port, tcp_connected_fn connected); 396 397struct tcp_pcb * tcp_listen_with_backlog_and_err(struct tcp_pcb *pcb, u8_t backlog, err_t *err); 398struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog); 399/** @ingroup tcp_raw */ 400#define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG) 401 402void tcp_abort (struct tcp_pcb *pcb); 403err_t tcp_close (struct tcp_pcb *pcb); 404err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx); 405 406/* Flags for "apiflags" parameter in tcp_write */ 407#define TCP_WRITE_FLAG_COPY 0x01 408#define TCP_WRITE_FLAG_MORE 0x02 409 410err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len, 411 u8_t apiflags); 412 413void tcp_setprio (struct tcp_pcb *pcb, u8_t prio); 414 415#define TCP_PRIO_MIN 1 416#define TCP_PRIO_NORMAL 64 417#define TCP_PRIO_MAX 127 418 419err_t tcp_output (struct tcp_pcb *pcb); 420 421 422const char* tcp_debug_state_str(enum tcp_state s); 423 424/* for compatibility with older implementation */ 425#define tcp_new_ip6() tcp_new_ip_type(IPADDR_TYPE_V6) 426 427#ifdef __cplusplus 428} 429#endif 430 431#endif /* LWIP_TCP */ 432 433#endif /* LWIP_HDR_TCP_H */ 434