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/mem.h" 40 #include "lwip/pbuf.h" 41 #include "lwip/ip.h" 42 #include "lwip/icmp.h" 43 #include "lwip/err.h" 44 45 #ifdef __cplusplus 46 extern "C" { 47 #endif 48 49 struct tcp_pcb; 50 51 /** Function prototype for tcp accept callback functions. Called when a new 52 * connection can be accepted on a listening pcb. 53 * 54 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 55 * @param newpcb The new connection pcb 56 * @param err An error code if there has been an error accepting. 57 * Only return ERR_ABRT if you have called tcp_abort from within the 58 * callback function! 59 */ 60 typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err); 61 62 /** Function prototype for tcp receive callback functions. Called when data has 63 * been received. 64 * 65 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 66 * @param tpcb The connection pcb which received data 67 * @param p The received data (or NULL when the connection has been closed!) 68 * @param err An error code if there has been an error receiving 69 * Only return ERR_ABRT if you have called tcp_abort from within the 70 * callback function! 71 */ 72 typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb, 73 struct pbuf *p, err_t err); 74 75 /** Function prototype for tcp sent callback functions. Called when sent data has 76 * been acknowledged by the remote side. Use it to free corresponding resources. 77 * This also means that the pcb has now space available to send new data. 78 * 79 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 80 * @param tpcb The connection pcb for which data has been acknowledged 81 * @param len The amount of bytes acknowledged 82 * @return ERR_OK: try to send some data by calling tcp_output 83 * Only return ERR_ABRT if you have called tcp_abort from within the 84 * callback function! 85 */ 86 typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb, 87 u16_t len); 88 89 /** Function prototype for tcp poll callback functions. Called periodically as 90 * specified by @see tcp_poll. 91 * 92 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 93 * @param tpcb tcp pcb 94 * @return ERR_OK: try to send some data by calling tcp_output 95 * Only return ERR_ABRT if you have called tcp_abort from within the 96 * callback function! 97 */ 98 typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb); 99 100 /** Function prototype for tcp error callback functions. Called when the pcb 101 * receives a RST or is unexpectedly closed for any other reason. 102 * 103 * @note The corresponding pcb is already freed when this callback is called! 104 * 105 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 106 * @param err Error code to indicate why the pcb has been closed 107 * ERR_ABRT: aborted through tcp_abort or by a TCP timer 108 * ERR_RST: the connection was reset by the remote host 109 */ 110 typedef void (*tcp_err_fn)(void *arg, err_t err); 111 112 /** Function prototype for tcp connected callback functions. Called when a pcb 113 * is connected to the remote side after initiating a connection attempt by 114 * calling tcp_connect(). 115 * 116 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 117 * @param tpcb The connection pcb which is connected 118 * @param err An unused error code, always ERR_OK currently ;-) TODO! 119 * Only return ERR_ABRT if you have called tcp_abort from within the 120 * callback function! 121 * 122 * @note When a connection attempt fails, the error callback is currently called! 123 */ 124 typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err); 125 126 enum tcp_state { 127 CLOSED = 0, 128 LISTEN = 1, 129 SYN_SENT = 2, 130 SYN_RCVD = 3, 131 ESTABLISHED = 4, 132 FIN_WAIT_1 = 5, 133 FIN_WAIT_2 = 6, 134 CLOSE_WAIT = 7, 135 CLOSING = 8, 136 LAST_ACK = 9, 137 TIME_WAIT = 10 138 }; 139 140 #if LWIP_CALLBACK_API 141 /* Function to call when a listener has been connected. 142 * @param arg user-supplied argument (tcp_pcb.callback_arg) 143 * @param pcb a new tcp_pcb that now is connected 144 * @param err an error argument (TODO: that is current always ERR_OK?) 145 * @return ERR_OK: accept the new connection, 146 * any other err_t abortsthe new connection 147 */ 148 #define DEF_ACCEPT_CALLBACK tcp_accept_fn accept; 149 #else /* LWIP_CALLBACK_API */ 150 #define DEF_ACCEPT_CALLBACK 151 #endif /* LWIP_CALLBACK_API */ 152 153 /** 154 * members common to struct tcp_pcb and struct tcp_listen_pcb 155 */ 156 #define TCP_PCB_COMMON(type) \ 157 type *next; /* for the linked list */ \ 158 void *callback_arg; \ 159 /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \ 160 DEF_ACCEPT_CALLBACK \ 161 enum tcp_state state; /* TCP state */ \ 162 u8_t prio; \ 163 /* ports are in host byte order */ \ 164 u16_t local_port 165 166 167 /* the TCP protocol control block */ 168 struct tcp_pcb { 169 /** common PCB members */ 170 IP_PCB; 171 /** protocol specific PCB members */ 172 TCP_PCB_COMMON(struct tcp_pcb); 173 174 /* ports are in host byte order */ 175 u16_t remote_port; 176 177 u8_t flags; 178 #define TF_ACK_DELAY ((u8_t)0x01U) /* Delayed ACK. */ 179 #define TF_ACK_NOW ((u8_t)0x02U) /* Immediate ACK. */ 180 #define TF_INFR ((u8_t)0x04U) /* In fast recovery. */ 181 #define TF_TIMESTAMP ((u8_t)0x08U) /* Timestamp option enabled */ 182 #define TF_RXCLOSED ((u8_t)0x10U) /* rx closed by tcp_shutdown */ 183 #define TF_FIN ((u8_t)0x20U) /* Connection was closed locally (FIN segment enqueued). */ 184 #define TF_NODELAY ((u8_t)0x40U) /* Disable Nagle algorithm */ 185 #define TF_NAGLEMEMERR ((u8_t)0x80U) /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */ 186 187 /* the rest of the fields are in host byte order 188 as we have to do some math with them */ 189 190 /* Timers */ 191 u8_t polltmr, pollinterval; 192 u8_t last_timer; 193 u32_t tmr; 194 195 /* receiver variables */ 196 u32_t rcv_nxt; /* next seqno expected */ 197 u16_t rcv_wnd; /* receiver window available */ 198 u16_t rcv_ann_wnd; /* receiver window to announce */ 199 u32_t rcv_ann_right_edge; /* announced right edge of window */ 200 201 /* Retransmission timer. */ 202 s16_t rtime; 203 204 u16_t mss; /* maximum segment size */ 205 206 /* RTT (round trip time) estimation variables */ 207 u32_t rttest; /* RTT estimate in 500ms ticks */ 208 u32_t rtseq; /* sequence number being timed */ 209 s16_t sa, sv; /* @todo document this */ 210 211 s16_t rto; /* retransmission time-out */ 212 u8_t nrtx; /* number of retransmissions */ 213 214 /* fast retransmit/recovery */ 215 u8_t dupacks; 216 u32_t lastack; /* Highest acknowledged seqno. */ 217 218 /* congestion avoidance/control variables */ 219 u16_t cwnd; 220 u16_t ssthresh; 221 222 /* sender variables */ 223 u32_t snd_nxt; /* next new seqno to be sent */ 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 u16_t snd_wnd; /* sender window */ 228 u16_t snd_wnd_max; /* the maximum sender window announced by the remote host */ 229 230 u16_t acked; 231 232 u16_t snd_buf; /* Available buffer space for sending (in bytes). */ 233 #define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3) 234 u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */ 235 236 #if TCP_OVERSIZE 237 /* Extra bytes available at the end of the last pbuf in unsent. */ 238 u16_t unsent_oversize; 239 #endif /* TCP_OVERSIZE */ 240 241 /* These are ordered by sequence number: */ 242 struct tcp_seg *unsent; /* Unsent (queued) segments. */ 243 struct tcp_seg *unacked; /* Sent but unacknowledged segments. */ 244 #if TCP_QUEUE_OOSEQ 245 struct tcp_seg *ooseq; /* Received out of sequence segments. */ 246 #endif /* TCP_QUEUE_OOSEQ */ 247 248 struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */ 249 250 #if LWIP_CALLBACK_API 251 /* Function to be called when more send buffer space is available. */ 252 tcp_sent_fn sent; 253 /* Function to be called when (in-sequence) data has arrived. */ 254 tcp_recv_fn recv; 255 /* Function to be called when a connection has been set up. */ 256 tcp_connected_fn connected; 257 /* Function which is called periodically. */ 258 tcp_poll_fn poll; 259 /* Function to be called whenever a fatal error occurs. */ 260 tcp_err_fn errf; 261 #endif /* LWIP_CALLBACK_API */ 262 263 #if LWIP_TCP_TIMESTAMPS 264 u32_t ts_lastacksent; 265 u32_t ts_recent; 266 #endif /* LWIP_TCP_TIMESTAMPS */ 267 268 /* idle time before KEEPALIVE is sent */ 269 u32_t keep_idle; 270 #if LWIP_TCP_KEEPALIVE 271 u32_t keep_intvl; 272 u32_t keep_cnt; 273 #endif /* LWIP_TCP_KEEPALIVE */ 274 275 /* Persist timer counter */ 276 u8_t persist_cnt; 277 /* Persist timer back-off */ 278 u8_t persist_backoff; 279 280 /* KEEPALIVE counter */ 281 u8_t keep_cnt_sent; 282 }; 283 284 struct tcp_pcb_listen { 285 /* Common members of all PCB types */ 286 IP_PCB; 287 /* Protocol specific PCB members */ 288 TCP_PCB_COMMON(struct tcp_pcb_listen); 289 290 #if TCP_LISTEN_BACKLOG 291 u8_t backlog; 292 u8_t accepts_pending; 293 #endif /* TCP_LISTEN_BACKLOG */ 294 }; 295 296 #if LWIP_EVENT_API 297 298 enum lwip_event { 299 LWIP_EVENT_ACCEPT, 300 LWIP_EVENT_SENT, 301 LWIP_EVENT_RECV, 302 LWIP_EVENT_CONNECTED, 303 LWIP_EVENT_POLL, 304 LWIP_EVENT_ERR 305 }; 306 307 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb, 308 enum lwip_event, 309 struct pbuf *p, 310 u16_t size, 311 err_t err); 312 313 #endif /* LWIP_EVENT_API */ 314 315 /* Application program's interface: */ 316 struct tcp_pcb * tcp_new (void); 317 318 void tcp_arg (struct tcp_pcb *pcb, void *arg); 319 void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept); 320 void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv); 321 void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent); 322 void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval); 323 void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err); 324 325 #define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss) 326 #define tcp_sndbuf(pcb) ((pcb)->snd_buf) 327 #define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen) 328 #define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY) 329 #define tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY) 330 #define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0) 331 332 #if TCP_LISTEN_BACKLOG 333 #define tcp_accepted(pcb) do { \ 334 LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \ 335 (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0) 336 #else /* TCP_LISTEN_BACKLOG */ 337 #define tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \ 338 (pcb)->state == LISTEN) 339 #endif /* TCP_LISTEN_BACKLOG */ 340 341 void tcp_recved (struct tcp_pcb *pcb, u16_t len); 342 err_t tcp_bind (struct tcp_pcb *pcb, ip_addr_t *ipaddr, 343 u16_t port); 344 err_t tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr, 345 u16_t port, tcp_connected_fn connected); 346 347 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog); 348 #define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG) 349 350 void tcp_abort (struct tcp_pcb *pcb); 351 err_t tcp_close (struct tcp_pcb *pcb); 352 err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx); 353 354 /* Flags for "apiflags" parameter in tcp_write */ 355 #define TCP_WRITE_FLAG_COPY 0x01 356 #define TCP_WRITE_FLAG_MORE 0x02 357 358 err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len, 359 u8_t apiflags); 360 361 void tcp_setprio (struct tcp_pcb *pcb, u8_t prio); 362 363 #define TCP_PRIO_MIN 1 364 #define TCP_PRIO_NORMAL 64 365 #define TCP_PRIO_MAX 127 366 367 err_t tcp_output (struct tcp_pcb *pcb); 368 369 370 const char* tcp_debug_state_str(enum tcp_state s); 371 372 373 #ifdef __cplusplus 374 } 375 #endif 376 377 #endif /* LWIP_TCP */ 378 379 #endif /* __LWIP_TCP_H__ */ 380