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 <[email protected]> 30 * 31 */ 32 #ifndef __LWIP_TCP_IMPL_H__ 33 #define __LWIP_TCP_IMPL_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/tcp.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 /* Functions for interfacing with TCP: */ 51 52 /* Lower layer interface to TCP: */ 53 void tcp_init (void); /* Initialize this module. */ 54 void tcp_tmr (void); /* Must be called every 55 TCP_TMR_INTERVAL 56 ms. (Typically 250 ms). */ 57 /* It is also possible to call these two functions at the right 58 intervals (instead of calling tcp_tmr()). */ 59 void tcp_slowtmr (void); 60 void tcp_fasttmr (void); 61 62 63 /* Only used by IP to pass a TCP segment to TCP: */ 64 void tcp_input (struct pbuf *p, struct netif *inp); 65 /* Used within the TCP code only: */ 66 struct tcp_pcb * tcp_alloc (u8_t prio); 67 void tcp_abandon (struct tcp_pcb *pcb, int reset); 68 err_t tcp_send_empty_ack(struct tcp_pcb *pcb); 69 void tcp_rexmit (struct tcp_pcb *pcb); 70 void tcp_rexmit_rto (struct tcp_pcb *pcb); 71 void tcp_rexmit_fast (struct tcp_pcb *pcb); 72 u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb); 73 err_t tcp_process_refused_data(struct tcp_pcb *pcb); 74 75 /** 76 * This is the Nagle algorithm: try to combine user data to send as few TCP 77 * segments as possible. Only send if 78 * - no previously transmitted data on the connection remains unacknowledged or 79 * - the TF_NODELAY flag is set (nagle algorithm turned off for this pcb) or 80 * - the only unsent segment is at least pcb->mss bytes long (or there is more 81 * than one unsent segment - with lwIP, this can happen although unsent->len < mss) 82 * - or if we are in fast-retransmit (TF_INFR) 83 */ 84 #define tcp_do_output_nagle(tpcb) ((((tpcb)->unacked == NULL) || \ 85 ((tpcb)->flags & (TF_NODELAY | TF_INFR)) || \ 86 (((tpcb)->unsent != NULL) && (((tpcb)->unsent->next != NULL) || \ 87 ((tpcb)->unsent->len >= (tpcb)->mss))) || \ 88 ((tcp_sndbuf(tpcb) == 0) || (tcp_sndqueuelen(tpcb) >= TCP_SND_QUEUELEN)) \ 89 ) ? 1 : 0) 90 #define tcp_output_nagle(tpcb) (tcp_do_output_nagle(tpcb) ? tcp_output(tpcb) : ERR_OK) 91 92 93 #define TCP_SEQ_LT(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) < 0) 94 #define TCP_SEQ_LEQ(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) <= 0) 95 #define TCP_SEQ_GT(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) > 0) 96 #define TCP_SEQ_GEQ(a,b) ((s32_t)((u32_t)(a) - (u32_t)(b)) >= 0) 97 /* is b<=a<=c? */ 98 #if 0 /* see bug #10548 */ 99 #define TCP_SEQ_BETWEEN(a,b,c) ((c)-(b) >= (a)-(b)) 100 #endif 101 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c)) 102 #define TCP_FIN 0x01U 103 #define TCP_SYN 0x02U 104 #define TCP_RST 0x04U 105 #define TCP_PSH 0x08U 106 #define TCP_ACK 0x10U 107 #define TCP_URG 0x20U 108 #define TCP_ECE 0x40U 109 #define TCP_CWR 0x80U 110 111 #define TCP_FLAGS 0x3fU 112 113 /* Length of the TCP header, excluding options. */ 114 #define TCP_HLEN 20 115 116 #ifndef TCP_TMR_INTERVAL 117 #define TCP_TMR_INTERVAL 250 /* The TCP timer interval in milliseconds. */ 118 #endif /* TCP_TMR_INTERVAL */ 119 120 #ifndef TCP_FAST_INTERVAL 121 #define TCP_FAST_INTERVAL TCP_TMR_INTERVAL /* the fine grained timeout in milliseconds */ 122 #endif /* TCP_FAST_INTERVAL */ 123 124 #ifndef TCP_SLOW_INTERVAL 125 #define TCP_SLOW_INTERVAL (2*TCP_TMR_INTERVAL) /* the coarse grained timeout in milliseconds */ 126 #endif /* TCP_SLOW_INTERVAL */ 127 128 #define TCP_FIN_WAIT_TIMEOUT 20000 /* milliseconds */ 129 #define TCP_SYN_RCVD_TIMEOUT 20000 /* milliseconds */ 130 131 #define TCP_OOSEQ_TIMEOUT 6U /* x RTO */ 132 133 #ifndef TCP_MSL 134 #define TCP_MSL 60000UL /* The maximum segment lifetime in milliseconds */ 135 #endif 136 137 /* Keepalive values, compliant with RFC 1122. Don't change this unless you know what you're doing */ 138 #ifndef TCP_KEEPIDLE_DEFAULT 139 #define TCP_KEEPIDLE_DEFAULT 7200000UL /* Default KEEPALIVE timer in milliseconds */ 140 #endif 141 142 #ifndef TCP_KEEPINTVL_DEFAULT 143 #define TCP_KEEPINTVL_DEFAULT 75000UL /* Default Time between KEEPALIVE probes in milliseconds */ 144 #endif 145 146 #ifndef TCP_KEEPCNT_DEFAULT 147 #define TCP_KEEPCNT_DEFAULT 9U /* Default Counter for KEEPALIVE probes */ 148 #endif 149 150 #define TCP_MAXIDLE TCP_KEEPCNT_DEFAULT * TCP_KEEPINTVL_DEFAULT /* Maximum KEEPALIVE probe time */ 151 152 /* Fields are (of course) in network byte order. 153 * Some fields are converted to host byte order in tcp_input(). 154 */ 155 #ifdef PACK_STRUCT_USE_INCLUDES 156 # include "arch/bpstruct.h" 157 #endif 158 PACK_STRUCT_BEGIN 159 struct tcp_hdr { 160 PACK_STRUCT_FIELD(u16_t src); 161 PACK_STRUCT_FIELD(u16_t dest); 162 PACK_STRUCT_FIELD(u32_t seqno); 163 PACK_STRUCT_FIELD(u32_t ackno); 164 PACK_STRUCT_FIELD(u16_t _hdrlen_rsvd_flags); 165 PACK_STRUCT_FIELD(u16_t wnd); 166 PACK_STRUCT_FIELD(u16_t chksum); 167 PACK_STRUCT_FIELD(u16_t urgp); 168 } PACK_STRUCT_STRUCT; 169 PACK_STRUCT_END 170 #ifdef PACK_STRUCT_USE_INCLUDES 171 # include "arch/epstruct.h" 172 #endif 173 174 #define TCPH_HDRLEN(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) >> 12) 175 #define TCPH_FLAGS(phdr) (ntohs((phdr)->_hdrlen_rsvd_flags) & TCP_FLAGS) 176 177 #define TCPH_HDRLEN_SET(phdr, len) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | TCPH_FLAGS(phdr)) 178 #define TCPH_FLAGS_SET(phdr, flags) (phdr)->_hdrlen_rsvd_flags = (((phdr)->_hdrlen_rsvd_flags & PP_HTONS((u16_t)(~(u16_t)(TCP_FLAGS)))) | htons(flags)) 179 #define TCPH_HDRLEN_FLAGS_SET(phdr, len, flags) (phdr)->_hdrlen_rsvd_flags = htons(((len) << 12) | (flags)) 180 181 #define TCPH_SET_FLAG(phdr, flags ) (phdr)->_hdrlen_rsvd_flags = ((phdr)->_hdrlen_rsvd_flags | htons(flags)) 182 #define TCPH_UNSET_FLAG(phdr, flags) (phdr)->_hdrlen_rsvd_flags = htons(ntohs((phdr)->_hdrlen_rsvd_flags) | (TCPH_FLAGS(phdr) & ~(flags)) ) 183 184 #define TCP_TCPLEN(seg) ((seg)->len + ((TCPH_FLAGS((seg)->tcphdr) & (TCP_FIN | TCP_SYN)) != 0)) 185 186 /** Flags used on input processing, not on pcb->flags 187 */ 188 #define TF_RESET (u8_t)0x08U /* Connection was reset. */ 189 #define TF_CLOSED (u8_t)0x10U /* Connection was sucessfully closed. */ 190 #define TF_GOT_FIN (u8_t)0x20U /* Connection was closed by the remote end. */ 191 192 193 #if LWIP_EVENT_API 194 195 #define TCP_EVENT_ACCEPT(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 196 LWIP_EVENT_ACCEPT, NULL, 0, err) 197 #define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 198 LWIP_EVENT_SENT, NULL, space, ERR_OK) 199 #define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 200 LWIP_EVENT_RECV, (p), 0, (err)) 201 #define TCP_EVENT_CLOSED(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 202 LWIP_EVENT_RECV, NULL, 0, ERR_OK) 203 #define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 204 LWIP_EVENT_CONNECTED, NULL, 0, (err)) 205 #define TCP_EVENT_POLL(pcb,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\ 206 LWIP_EVENT_POLL, NULL, 0, ERR_OK) 207 #define TCP_EVENT_ERR(errf,arg,err) lwip_tcp_event((arg), NULL, \ 208 LWIP_EVENT_ERR, NULL, 0, (err)) 209 210 #else /* LWIP_EVENT_API */ 211 212 #define TCP_EVENT_ACCEPT(pcb,err,ret) \ 213 do { \ 214 if((pcb)->accept != NULL) \ 215 (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err)); \ 216 else (ret) = ERR_ARG; \ 217 } while (0) 218 219 #define TCP_EVENT_SENT(pcb,space,ret) \ 220 do { \ 221 if((pcb)->sent != NULL) \ 222 (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space)); \ 223 else (ret) = ERR_OK; \ 224 } while (0) 225 226 #define TCP_EVENT_RECV(pcb,p,err,ret) \ 227 do { \ 228 if((pcb)->recv != NULL) { \ 229 (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err));\ 230 } else { \ 231 (ret) = tcp_recv_null(NULL, (pcb), (p), (err)); \ 232 } \ 233 } while (0) 234 235 #define TCP_EVENT_CLOSED(pcb,ret) \ 236 do { \ 237 if(((pcb)->recv != NULL)) { \ 238 (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\ 239 } else { \ 240 (ret) = ERR_OK; \ 241 } \ 242 } while (0) 243 244 #define TCP_EVENT_CONNECTED(pcb,err,ret) \ 245 do { \ 246 if((pcb)->connected != NULL) \ 247 (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \ 248 else (ret) = ERR_OK; \ 249 } while (0) 250 251 #define TCP_EVENT_POLL(pcb,ret) \ 252 do { \ 253 if((pcb)->poll != NULL) \ 254 (ret) = (pcb)->poll((pcb)->callback_arg,(pcb)); \ 255 else (ret) = ERR_OK; \ 256 } while (0) 257 258 #define TCP_EVENT_ERR(errf,arg,err) \ 259 do { \ 260 if((errf) != NULL) \ 261 (errf)((arg),(err)); \ 262 } while (0) 263 264 #endif /* LWIP_EVENT_API */ 265 266 /** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */ 267 #if TCP_OVERSIZE && defined(LWIP_DEBUG) 268 #define TCP_OVERSIZE_DBGCHECK 1 269 #else 270 #define TCP_OVERSIZE_DBGCHECK 0 271 #endif 272 273 /** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */ 274 #define TCP_CHECKSUM_ON_COPY (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP) 275 276 /* This structure represents a TCP segment on the unsent, unacked and ooseq queues */ 277 struct tcp_seg { 278 struct tcp_seg *next; /* used when putting segements on a queue */ 279 struct pbuf *p; /* buffer containing data + TCP header */ 280 u16_t len; /* the TCP length of this segment */ 281 #if TCP_OVERSIZE_DBGCHECK 282 u16_t oversize_left; /* Extra bytes available at the end of the last 283 pbuf in unsent (used for asserting vs. 284 tcp_pcb.unsent_oversized only) */ 285 #endif /* TCP_OVERSIZE_DBGCHECK */ 286 #if TCP_CHECKSUM_ON_COPY 287 u16_t chksum; 288 u8_t chksum_swapped; 289 #endif /* TCP_CHECKSUM_ON_COPY */ 290 u8_t flags; 291 #define TF_SEG_OPTS_MSS (u8_t)0x01U /* Include MSS option. */ 292 #define TF_SEG_OPTS_TS (u8_t)0x02U /* Include timestamp option. */ 293 #define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is 294 checksummed into 'chksum' */ 295 struct tcp_hdr *tcphdr; /* the TCP header */ 296 }; 297 298 #define LWIP_TCP_OPT_LENGTH(flags) \ 299 (flags & TF_SEG_OPTS_MSS ? 4 : 0) + \ 300 (flags & TF_SEG_OPTS_TS ? 12 : 0) 301 302 /** This returns a TCP header option for MSS in an u32_t */ 303 #define TCP_BUILD_MSS_OPTION(mss) htonl(0x02040000 | ((mss) & 0xFFFF)) 304 305 /* Global variables: */ 306 extern struct tcp_pcb *tcp_input_pcb; 307 extern u32_t tcp_ticks; 308 extern u8_t tcp_active_pcbs_changed; 309 310 /* The TCP PCB lists. */ 311 union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */ 312 struct tcp_pcb_listen *listen_pcbs; 313 struct tcp_pcb *pcbs; 314 }; 315 extern struct tcp_pcb *tcp_bound_pcbs; 316 extern union tcp_listen_pcbs_t tcp_listen_pcbs; 317 extern struct tcp_pcb *tcp_active_pcbs; /* List of all TCP PCBs that are in a 318 state in which they accept or send 319 data. */ 320 extern struct tcp_pcb *tcp_tw_pcbs; /* List of all TCP PCBs in TIME-WAIT. */ 321 322 extern struct tcp_pcb *tcp_tmp_pcb; /* Only used for temporary storage. */ 323 324 /* Axioms about the above lists: 325 1) Every TCP PCB that is not CLOSED is in one of the lists. 326 2) A PCB is only in one of the lists. 327 3) All PCBs in the tcp_listen_pcbs list is in LISTEN state. 328 4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state. 329 */ 330 /* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB 331 with a PCB list or removes a PCB from a list, respectively. */ 332 #ifndef TCP_DEBUG_PCB_LISTS 333 #define TCP_DEBUG_PCB_LISTS 0 334 #endif 335 #if TCP_DEBUG_PCB_LISTS 336 #define TCP_REG(pcbs, npcb) do {\ 337 LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", (npcb), (npcb)->local_port)); \ 338 for(tcp_tmp_pcb = *(pcbs); \ 339 tcp_tmp_pcb != NULL; \ 340 tcp_tmp_pcb = tcp_tmp_pcb->next) { \ 341 LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != (npcb)); \ 342 } \ 343 LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", ((pcbs) == &tcp_bound_pcbs) || ((npcb)->state != CLOSED)); \ 344 (npcb)->next = *(pcbs); \ 345 LWIP_ASSERT("TCP_REG: npcb->next != npcb", (npcb)->next != (npcb)); \ 346 *(pcbs) = (npcb); \ 347 LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \ 348 tcp_timer_needed(); \ 349 } while(0) 350 #define TCP_RMV(pcbs, npcb) do { \ 351 LWIP_ASSERT("TCP_RMV: pcbs != NULL", *(pcbs) != NULL); \ 352 LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", (npcb), *(pcbs))); \ 353 if(*(pcbs) == (npcb)) { \ 354 *(pcbs) = (*pcbs)->next; \ 355 } else for(tcp_tmp_pcb = *(pcbs); tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \ 356 if(tcp_tmp_pcb->next == (npcb)) { \ 357 tcp_tmp_pcb->next = (npcb)->next; \ 358 break; \ 359 } \ 360 } \ 361 (npcb)->next = NULL; \ 362 LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \ 363 LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", (npcb), *(pcbs))); \ 364 } while(0) 365 366 #else /* LWIP_DEBUG */ 367 368 #define TCP_REG(pcbs, npcb) \ 369 do { \ 370 (npcb)->next = *pcbs; \ 371 *(pcbs) = (npcb); \ 372 tcp_timer_needed(); \ 373 } while (0) 374 375 #define TCP_RMV(pcbs, npcb) \ 376 do { \ 377 if(*(pcbs) == (npcb)) { \ 378 (*(pcbs)) = (*pcbs)->next; \ 379 } \ 380 else { \ 381 for(tcp_tmp_pcb = *pcbs; \ 382 tcp_tmp_pcb != NULL; \ 383 tcp_tmp_pcb = tcp_tmp_pcb->next) { \ 384 if(tcp_tmp_pcb->next == (npcb)) { \ 385 tcp_tmp_pcb->next = (npcb)->next; \ 386 break; \ 387 } \ 388 } \ 389 } \ 390 (npcb)->next = NULL; \ 391 } while(0) 392 393 #endif /* LWIP_DEBUG */ 394 395 #define TCP_REG_ACTIVE(npcb) \ 396 do { \ 397 TCP_REG(&tcp_active_pcbs, npcb); \ 398 tcp_active_pcbs_changed = 1; \ 399 } while (0) 400 401 #define TCP_RMV_ACTIVE(npcb) \ 402 do { \ 403 TCP_RMV(&tcp_active_pcbs, npcb); \ 404 tcp_active_pcbs_changed = 1; \ 405 } while (0) 406 407 #define TCP_PCB_REMOVE_ACTIVE(pcb) \ 408 do { \ 409 tcp_pcb_remove(&tcp_active_pcbs, pcb); \ 410 tcp_active_pcbs_changed = 1; \ 411 } while (0) 412 413 414 /* Internal functions: */ 415 struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb); 416 void tcp_pcb_purge(struct tcp_pcb *pcb); 417 void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb); 418 419 void tcp_segs_free(struct tcp_seg *seg); 420 void tcp_seg_free(struct tcp_seg *seg); 421 struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg); 422 423 #define tcp_ack(pcb) \ 424 do { \ 425 if((pcb)->flags & TF_ACK_DELAY) { \ 426 (pcb)->flags &= ~TF_ACK_DELAY; \ 427 (pcb)->flags |= TF_ACK_NOW; \ 428 } \ 429 else { \ 430 (pcb)->flags |= TF_ACK_DELAY; \ 431 } \ 432 } while (0) 433 434 #define tcp_ack_now(pcb) \ 435 do { \ 436 (pcb)->flags |= TF_ACK_NOW; \ 437 } while (0) 438 439 err_t tcp_send_fin(struct tcp_pcb *pcb); 440 err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags); 441 442 void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg); 443 444 void tcp_rst(u32_t seqno, u32_t ackno, 445 ip_addr_t *local_ip, ip_addr_t *remote_ip, 446 u16_t local_port, u16_t remote_port); 447 448 u32_t tcp_next_iss(void); 449 450 void tcp_keepalive(struct tcp_pcb *pcb); 451 void tcp_zero_window_probe(struct tcp_pcb *pcb); 452 453 #if TCP_CALCULATE_EFF_SEND_MSS 454 u16_t tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr); 455 #endif /* TCP_CALCULATE_EFF_SEND_MSS */ 456 457 #if LWIP_CALLBACK_API 458 err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err); 459 #endif /* LWIP_CALLBACK_API */ 460 461 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG 462 void tcp_debug_print(struct tcp_hdr *tcphdr); 463 void tcp_debug_print_flags(u8_t flags); 464 void tcp_debug_print_state(enum tcp_state s); 465 void tcp_debug_print_pcbs(void); 466 s16_t tcp_pcbs_sane(void); 467 #else 468 # define tcp_debug_print(tcphdr) 469 # define tcp_debug_print_flags(flags) 470 # define tcp_debug_print_state(s) 471 # define tcp_debug_print_pcbs() 472 # define tcp_pcbs_sane() 1 473 #endif /* TCP_DEBUG */ 474 475 /** External function (implemented in timers.c), called when TCP detects 476 * that a timer is needed (i.e. active- or time-wait-pcb found). */ 477 void tcp_timer_needed(void); 478 479 480 #ifdef __cplusplus 481 } 482 #endif 483 484 #endif /* LWIP_TCP */ 485 486 #endif /* __LWIP_TCP_H__ */ 487