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 (at) 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 (0xffffU-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 }; 281 282 struct tcp_pcb_listen { 283 /* Common members of all PCB types */ 284 IP_PCB; 285 /* Protocol specific PCB members */ 286 TCP_PCB_COMMON(struct tcp_pcb_listen); 287 288 #if TCP_LISTEN_BACKLOG 289 u8_t backlog; 290 u8_t accepts_pending; 291 #endif /* TCP_LISTEN_BACKLOG */ 292 }; 293 294 #if LWIP_EVENT_API 295 296 enum lwip_event { 297 LWIP_EVENT_ACCEPT, 298 LWIP_EVENT_SENT, 299 LWIP_EVENT_RECV, 300 LWIP_EVENT_CONNECTED, 301 LWIP_EVENT_POLL, 302 LWIP_EVENT_ERR 303 }; 304 305 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb, 306 enum lwip_event, 307 struct pbuf *p, 308 u16_t size, 309 err_t err); 310 311 #endif /* LWIP_EVENT_API */ 312 313 /* Application program's interface: */ 314 struct tcp_pcb * tcp_new (void); 315 316 void tcp_arg (struct tcp_pcb *pcb, void *arg); 317 void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept); 318 void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv); 319 void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent); 320 void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval); 321 void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err); 322 323 #define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss) 324 #define tcp_sndbuf(pcb) ((pcb)->snd_buf) 325 #define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen) 326 #define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY) 327 #define tcp_nagle_enable(pcb) ((pcb)->flags &= ~TF_NODELAY) 328 #define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0) 329 330 #if TCP_LISTEN_BACKLOG 331 #define tcp_accepted(pcb) do { \ 332 LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \ 333 (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0) 334 #else /* TCP_LISTEN_BACKLOG */ 335 #define tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \ 336 pcb->state == LISTEN) 337 #endif /* TCP_LISTEN_BACKLOG */ 338 339 void tcp_recved (struct tcp_pcb *pcb, u16_t len); 340 err_t tcp_bind (struct tcp_pcb *pcb, ip_addr_t *ipaddr, 341 u16_t port); 342 err_t tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr, 343 u16_t port, tcp_connected_fn connected); 344 345 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog); 346 #define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG) 347 348 void tcp_abort (struct tcp_pcb *pcb); 349 err_t tcp_close (struct tcp_pcb *pcb); 350 err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx); 351 352 /* Flags for "apiflags" parameter in tcp_write */ 353 #define TCP_WRITE_FLAG_COPY 0x01 354 #define TCP_WRITE_FLAG_MORE 0x02 355 356 err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len, 357 u8_t apiflags); 358 359 void tcp_setprio (struct tcp_pcb *pcb, u8_t prio); 360 361 #define TCP_PRIO_MIN 1 362 #define TCP_PRIO_NORMAL 64 363 #define TCP_PRIO_MAX 127 364 365 err_t tcp_output (struct tcp_pcb *pcb); 366 367 368 const char* tcp_debug_state_str(enum tcp_state s); 369 370 371 #ifdef __cplusplus 372 } 373 #endif 374 375 #endif /* LWIP_TCP */ 376 377 #endif /* __LWIP_TCP_H__ */ 378
