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tcp.h
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00001 /** 00002 * @file 00003 * TCP API (to be used from TCPIP thread)\n 00004 * See also @ref tcp_raw 00005 */ 00006 00007 /* 00008 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00009 * All rights reserved. 00010 * 00011 * Redistribution and use in source and binary forms, with or without modification, 00012 * are permitted provided that the following conditions are met: 00013 * 00014 * 1. Redistributions of source code must retain the above copyright notice, 00015 * this list of conditions and the following disclaimer. 00016 * 2. Redistributions in binary form must reproduce the above copyright notice, 00017 * this list of conditions and the following disclaimer in the documentation 00018 * and/or other materials provided with the distribution. 00019 * 3. The name of the author may not be used to endorse or promote products 00020 * derived from this software without specific prior written permission. 00021 * 00022 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00023 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00024 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00025 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00026 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00027 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00028 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00029 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00030 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00031 * OF SUCH DAMAGE. 00032 * 00033 * This file is part of the lwIP TCP/IP stack. 00034 * 00035 * Author: Adam Dunkels <adam@sics.se> 00036 * 00037 */ 00038 #ifndef LWIP_HDR_TCP_H 00039 #define LWIP_HDR_TCP_H 00040 00041 #include "lwip/opt.h" 00042 00043 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ 00044 00045 #include "lwip/mem.h" 00046 #include "lwip/pbuf.h" 00047 #include "lwip/ip.h" 00048 #include "lwip/icmp.h" 00049 #include "lwip/err.h" 00050 #include "lwip/ip6.h" 00051 #include "lwip/ip6_addr.h" 00052 00053 #ifdef __cplusplus 00054 extern "C" { 00055 #endif 00056 00057 struct tcp_pcb; 00058 00059 /** Function prototype for tcp accept callback functions. Called when a new 00060 * connection can be accepted on a listening pcb. 00061 * 00062 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00063 * @param newpcb The new connection pcb 00064 * @param err An error code if there has been an error accepting. 00065 * Only return ERR_ABRT if you have called tcp_abort from within the 00066 * callback function! 00067 */ 00068 typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err); 00069 00070 /** Function prototype for tcp receive callback functions. Called when data has 00071 * been received. 00072 * 00073 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00074 * @param tpcb The connection pcb which received data 00075 * @param p The received data (or NULL when the connection has been closed!) 00076 * @param err An error code if there has been an error receiving 00077 * Only return ERR_ABRT if you have called tcp_abort from within the 00078 * callback function! 00079 */ 00080 typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb, 00081 struct pbuf *p, err_t err); 00082 00083 /** Function prototype for tcp sent callback functions. Called when sent data has 00084 * been acknowledged by the remote side. Use it to free corresponding resources. 00085 * This also means that the pcb has now space available to send new data. 00086 * 00087 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00088 * @param tpcb The connection pcb for which data has been acknowledged 00089 * @param len The amount of bytes acknowledged 00090 * @return ERR_OK: try to send some data by calling tcp_output 00091 * Only return ERR_ABRT if you have called tcp_abort from within the 00092 * callback function! 00093 */ 00094 typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb, 00095 u16_t len); 00096 00097 /** Function prototype for tcp poll callback functions. Called periodically as 00098 * specified by @see tcp_poll. 00099 * 00100 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00101 * @param tpcb tcp pcb 00102 * @return ERR_OK: try to send some data by calling tcp_output 00103 * Only return ERR_ABRT if you have called tcp_abort from within the 00104 * callback function! 00105 */ 00106 typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb); 00107 00108 /** Function prototype for tcp error callback functions. Called when the pcb 00109 * receives a RST or is unexpectedly closed for any other reason. 00110 * 00111 * @note The corresponding pcb is already freed when this callback is called! 00112 * 00113 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00114 * @param err Error code to indicate why the pcb has been closed 00115 * ERR_ABRT: aborted through tcp_abort or by a TCP timer 00116 * ERR_RST: the connection was reset by the remote host 00117 */ 00118 typedef void (*tcp_err_fn)(void *arg, err_t err); 00119 00120 /** Function prototype for tcp connected callback functions. Called when a pcb 00121 * is connected to the remote side after initiating a connection attempt by 00122 * calling tcp_connect(). 00123 * 00124 * @param arg Additional argument to pass to the callback function (@see tcp_arg()) 00125 * @param tpcb The connection pcb which is connected 00126 * @param err An unused error code, always ERR_OK currently ;-) @todo! 00127 * Only return ERR_ABRT if you have called tcp_abort from within the 00128 * callback function! 00129 * 00130 * @note When a connection attempt fails, the error callback is currently called! 00131 */ 00132 typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err); 00133 00134 #if LWIP_WND_SCALE 00135 #define RCV_WND_SCALE(pcb, wnd) (((wnd) >> (pcb)->rcv_scale)) 00136 #define SND_WND_SCALE(pcb, wnd) (((wnd) << (pcb)->snd_scale)) 00137 #define TCPWND16(x) ((u16_t)LWIP_MIN((x), 0xFFFF)) 00138 #define TCP_WND_MAX(pcb) ((tcpwnd_size_t)(((pcb)->flags & TF_WND_SCALE) ? TCP_WND : TCPWND16(TCP_WND))) 00139 typedef u32_t tcpwnd_size_t; 00140 #else 00141 #define RCV_WND_SCALE(pcb, wnd) (wnd) 00142 #define SND_WND_SCALE(pcb, wnd) (wnd) 00143 #define TCPWND16(x) (x) 00144 #define TCP_WND_MAX(pcb) TCP_WND 00145 typedef u16_t tcpwnd_size_t; 00146 #endif 00147 00148 #if LWIP_WND_SCALE || TCP_LISTEN_BACKLOG || LWIP_TCP_TIMESTAMPS 00149 typedef u16_t tcpflags_t; 00150 #else 00151 typedef u8_t tcpflags_t; 00152 #endif 00153 00154 enum tcp_state { 00155 CLOSED = 0, 00156 LISTEN = 1, 00157 SYN_SENT = 2, 00158 SYN_RCVD = 3, 00159 ESTABLISHED = 4, 00160 FIN_WAIT_1 = 5, 00161 FIN_WAIT_2 = 6, 00162 CLOSE_WAIT = 7, 00163 CLOSING = 8, 00164 LAST_ACK = 9, 00165 TIME_WAIT = 10 00166 }; 00167 00168 /** 00169 * members common to struct tcp_pcb and struct tcp_listen_pcb 00170 */ 00171 #define TCP_PCB_COMMON(type) \ 00172 type *next; /* for the linked list */ \ 00173 void *callback_arg; \ 00174 enum tcp_state state; /* TCP state */ \ 00175 u8_t prio; \ 00176 /* ports are in host byte order */ \ 00177 u16_t local_port 00178 00179 00180 /** the TCP protocol control block for listening pcbs */ 00181 struct tcp_pcb_listen { 00182 /** Common members of all PCB types */ 00183 IP_PCB; 00184 /** Protocol specific PCB members */ 00185 TCP_PCB_COMMON(struct tcp_pcb_listen); 00186 00187 #if LWIP_CALLBACK_API 00188 /* Function to call when a listener has been connected. */ 00189 tcp_accept_fn accept; 00190 #endif /* LWIP_CALLBACK_API */ 00191 00192 #if TCP_LISTEN_BACKLOG 00193 u8_t backlog; 00194 u8_t accepts_pending; 00195 #endif /* TCP_LISTEN_BACKLOG */ 00196 }; 00197 00198 00199 /** the TCP protocol control block */ 00200 struct tcp_pcb { 00201 /** common PCB members */ 00202 IP_PCB; 00203 /** protocol specific PCB members */ 00204 TCP_PCB_COMMON(struct tcp_pcb); 00205 00206 /* ports are in host byte order */ 00207 u16_t remote_port; 00208 00209 tcpflags_t flags; 00210 #define TF_ACK_DELAY 0x01U /* Delayed ACK. */ 00211 #define TF_ACK_NOW 0x02U /* Immediate ACK. */ 00212 #define TF_INFR 0x04U /* In fast recovery. */ 00213 #define TF_CLOSEPEND 0x08U /* If this is set, tcp_close failed to enqueue the FIN (retried in tcp_tmr) */ 00214 #define TF_RXCLOSED 0x10U /* rx closed by tcp_shutdown */ 00215 #define TF_FIN 0x20U /* Connection was closed locally (FIN segment enqueued). */ 00216 #define TF_NODELAY 0x40U /* Disable Nagle algorithm */ 00217 #define TF_NAGLEMEMERR 0x80U /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */ 00218 #if LWIP_WND_SCALE 00219 #define TF_WND_SCALE 0x0100U /* Window Scale option enabled */ 00220 #endif 00221 #if TCP_LISTEN_BACKLOG 00222 #define TF_BACKLOGPEND 0x0200U /* If this is set, a connection pcb has increased the backlog on its listener */ 00223 #endif 00224 #if LWIP_TCP_TIMESTAMPS 00225 #define TF_TIMESTAMP 0x0400U /* Timestamp option enabled */ 00226 #endif 00227 00228 /* the rest of the fields are in host byte order 00229 as we have to do some math with them */ 00230 00231 /* Timers */ 00232 u8_t polltmr, pollinterval; 00233 u8_t last_timer; 00234 u32_t tmr; 00235 00236 /* receiver variables */ 00237 u32_t rcv_nxt; /* next seqno expected */ 00238 tcpwnd_size_t rcv_wnd; /* receiver window available */ 00239 tcpwnd_size_t rcv_ann_wnd; /* receiver window to announce */ 00240 u32_t rcv_ann_right_edge; /* announced right edge of window */ 00241 00242 /* Retransmission timer. */ 00243 s16_t rtime; 00244 00245 u16_t mss; /* maximum segment size */ 00246 00247 /* RTT (round trip time) estimation variables */ 00248 u32_t rttest; /* RTT estimate in 500ms ticks */ 00249 u32_t rtseq; /* sequence number being timed */ 00250 s16_t sa, sv; /* @todo document this */ 00251 00252 s16_t rto; /* retransmission time-out */ 00253 u8_t nrtx; /* number of retransmissions */ 00254 00255 /* fast retransmit/recovery */ 00256 u8_t dupacks; 00257 u32_t lastack; /* Highest acknowledged seqno. */ 00258 00259 /* congestion avoidance/control variables */ 00260 tcpwnd_size_t cwnd; 00261 tcpwnd_size_t ssthresh; 00262 00263 /* sender variables */ 00264 u32_t snd_nxt; /* next new seqno to be sent */ 00265 u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last 00266 window update. */ 00267 u32_t snd_lbb; /* Sequence number of next byte to be buffered. */ 00268 tcpwnd_size_t snd_wnd; /* sender window */ 00269 tcpwnd_size_t snd_wnd_max; /* the maximum sender window announced by the remote host */ 00270 00271 tcpwnd_size_t snd_buf; /* Available buffer space for sending (in bytes). */ 00272 #define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3) 00273 u16_t snd_queuelen; /* Number of pbufs currently in the send buffer. */ 00274 00275 #if TCP_OVERSIZE 00276 /* Extra bytes available at the end of the last pbuf in unsent. */ 00277 u16_t unsent_oversize; 00278 #endif /* TCP_OVERSIZE */ 00279 00280 /* These are ordered by sequence number: */ 00281 struct tcp_seg *unsent; /* Unsent (queued) segments. */ 00282 struct tcp_seg *unacked; /* Sent but unacknowledged segments. */ 00283 #if TCP_QUEUE_OOSEQ 00284 struct tcp_seg *ooseq; /* Received out of sequence segments. */ 00285 #endif /* TCP_QUEUE_OOSEQ */ 00286 00287 struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */ 00288 00289 #if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG 00290 struct tcp_pcb_listen* listener; 00291 #endif /* LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG */ 00292 00293 #if LWIP_CALLBACK_API 00294 /* Function to be called when more send buffer space is available. */ 00295 tcp_sent_fn sent; 00296 /* Function to be called when (in-sequence) data has arrived. */ 00297 tcp_recv_fn recv; 00298 /* Function to be called when a connection has been set up. */ 00299 tcp_connected_fn connected; 00300 /* Function which is called periodically. */ 00301 tcp_poll_fn poll; 00302 /* Function to be called whenever a fatal error occurs. */ 00303 tcp_err_fn errf; 00304 #endif /* LWIP_CALLBACK_API */ 00305 00306 #if LWIP_TCP_TIMESTAMPS 00307 u32_t ts_lastacksent; 00308 u32_t ts_recent; 00309 #endif /* LWIP_TCP_TIMESTAMPS */ 00310 00311 /* idle time before KEEPALIVE is sent */ 00312 u32_t keep_idle; 00313 #if LWIP_TCP_KEEPALIVE 00314 u32_t keep_intvl; 00315 u32_t keep_cnt; 00316 #endif /* LWIP_TCP_KEEPALIVE */ 00317 00318 /* Persist timer counter */ 00319 u8_t persist_cnt; 00320 /* Persist timer back-off */ 00321 u8_t persist_backoff; 00322 00323 /* KEEPALIVE counter */ 00324 u8_t keep_cnt_sent; 00325 00326 #if LWIP_WND_SCALE 00327 u8_t snd_scale; 00328 u8_t rcv_scale; 00329 #endif 00330 }; 00331 00332 #if LWIP_EVENT_API 00333 00334 enum lwip_event { 00335 LWIP_EVENT_ACCEPT, 00336 LWIP_EVENT_SENT, 00337 LWIP_EVENT_RECV, 00338 LWIP_EVENT_CONNECTED, 00339 LWIP_EVENT_POLL, 00340 LWIP_EVENT_ERR 00341 }; 00342 00343 err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb, 00344 enum lwip_event, 00345 struct pbuf *p, 00346 u16_t size, 00347 err_t err); 00348 00349 #endif /* LWIP_EVENT_API */ 00350 00351 /* Application program's interface: */ 00352 struct tcp_pcb * tcp_new (void); 00353 struct tcp_pcb * tcp_new_ip_type (u8_t type); 00354 00355 void tcp_arg (struct tcp_pcb *pcb, void *arg); 00356 #if LWIP_CALLBACK_API 00357 void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv); 00358 void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent); 00359 void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err); 00360 void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept); 00361 #endif /* LWIP_CALLBACK_API */ 00362 void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval); 00363 00364 #if LWIP_TCP_TIMESTAMPS 00365 #define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss) 00366 #else /* LWIP_TCP_TIMESTAMPS */ 00367 #define tcp_mss(pcb) ((pcb)->mss) 00368 #endif /* LWIP_TCP_TIMESTAMPS */ 00369 #define tcp_sndbuf(pcb) (TCPWND16((pcb)->snd_buf)) 00370 #define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen) 00371 /** @ingroup tcp_raw */ 00372 #define tcp_nagle_disable(pcb) ((pcb)->flags |= TF_NODELAY) 00373 /** @ingroup tcp_raw */ 00374 #define tcp_nagle_enable(pcb) ((pcb)->flags = (tcpflags_t)((pcb)->flags & ~TF_NODELAY)) 00375 /** @ingroup tcp_raw */ 00376 #define tcp_nagle_disabled(pcb) (((pcb)->flags & TF_NODELAY) != 0) 00377 00378 #if TCP_LISTEN_BACKLOG 00379 #define tcp_backlog_set(pcb, new_backlog) do { \ 00380 LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", (pcb)->state == LISTEN); \ 00381 ((struct tcp_pcb_listen *)(pcb))->backlog = ((new_backlog) ? (new_backlog) : 1); } while(0) 00382 void tcp_backlog_delayed(struct tcp_pcb* pcb); 00383 void tcp_backlog_accepted(struct tcp_pcb* pcb); 00384 #else /* TCP_LISTEN_BACKLOG */ 00385 #define tcp_backlog_set(pcb, new_backlog) 00386 #define tcp_backlog_delayed(pcb) 00387 #define tcp_backlog_accepted(pcb) 00388 #endif /* TCP_LISTEN_BACKLOG */ 00389 #define tcp_accepted(pcb) /* compatibility define, not needed any more */ 00390 00391 void tcp_recved (struct tcp_pcb *pcb, u16_t len); 00392 err_t tcp_bind (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, 00393 u16_t port); 00394 err_t tcp_connect (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, 00395 u16_t port, tcp_connected_fn connected); 00396 00397 struct tcp_pcb * tcp_listen_with_backlog_and_err(struct tcp_pcb *pcb, u8_t backlog, err_t *err); 00398 struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog); 00399 /** @ingroup tcp_raw */ 00400 #define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG) 00401 00402 void tcp_abort (struct tcp_pcb *pcb); 00403 err_t tcp_close (struct tcp_pcb *pcb); 00404 err_t tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx); 00405 00406 /* Flags for "apiflags" parameter in tcp_write */ 00407 #define TCP_WRITE_FLAG_COPY 0x01 00408 #define TCP_WRITE_FLAG_MORE 0x02 00409 00410 err_t tcp_write (struct tcp_pcb *pcb, const void *dataptr, u16_t len, 00411 u8_t apiflags); 00412 00413 void tcp_setprio (struct tcp_pcb *pcb, u8_t prio); 00414 00415 #define TCP_PRIO_MIN 1 00416 #define TCP_PRIO_NORMAL 64 00417 #define TCP_PRIO_MAX 127 00418 00419 err_t tcp_output (struct tcp_pcb *pcb); 00420 00421 00422 const char* tcp_debug_state_str(enum tcp_state s); 00423 00424 /* for compatibility with older implementation */ 00425 #define tcp_new_ip6() tcp_new_ip_type(IPADDR_TYPE_V6) 00426 00427 #ifdef __cplusplus 00428 } 00429 #endif 00430 00431 #endif /* LWIP_TCP */ 00432 00433 #endif /* LWIP_HDR_TCP_H */
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