I messed up the merge, so pushing it over to another repo so I don't lose it. Will tidy up and remove later
Dependencies: BufferedSerial FatFileSystemCpp mbed
tcp.c
00001 /** 00002 * @file 00003 * Transmission Control Protocol for IP 00004 * 00005 * This file contains common functions for the TCP implementation, such as functinos 00006 * for manipulating the data structures and the TCP timer functions. TCP functions 00007 * related to input and output is found in tcp_in.c and tcp_out.c respectively. 00008 * 00009 */ 00010 00011 /* 00012 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 00013 * All rights reserved. 00014 * 00015 * Redistribution and use in source and binary forms, with or without modification, 00016 * are permitted provided that the following conditions are met: 00017 * 00018 * 1. Redistributions of source code must retain the above copyright notice, 00019 * this list of conditions and the following disclaimer. 00020 * 2. Redistributions in binary form must reproduce the above copyright notice, 00021 * this list of conditions and the following disclaimer in the documentation 00022 * and/or other materials provided with the distribution. 00023 * 3. The name of the author may not be used to endorse or promote products 00024 * derived from this software without specific prior written permission. 00025 * 00026 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 00027 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 00028 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 00029 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 00030 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 00031 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 00032 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 00033 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 00034 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 00035 * OF SUCH DAMAGE. 00036 * 00037 * This file is part of the lwIP TCP/IP stack. 00038 * 00039 * Author: Adam Dunkels <adam@sics.se> 00040 * 00041 */ 00042 00043 #include "lwip/opt.h" 00044 00045 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ 00046 00047 #include "lwip/def.h" 00048 #include "lwip/mem.h" 00049 #include "lwip/memp.h" 00050 #include "lwip/snmp.h" 00051 #include "lwip/tcp.h" 00052 #include "lwip/tcp_impl.h" 00053 #include "lwip/debug.h" 00054 #include "lwip/stats.h" 00055 00056 #include <string.h> 00057 00058 const char * const tcp_state_str[] = { 00059 "CLOSED", 00060 "LISTEN", 00061 "SYN_SENT", 00062 "SYN_RCVD", 00063 "ESTABLISHED", 00064 "FIN_WAIT_1", 00065 "FIN_WAIT_2", 00066 "CLOSE_WAIT", 00067 "CLOSING", 00068 "LAST_ACK", 00069 "TIME_WAIT" 00070 }; 00071 00072 /* Incremented every coarse grained timer shot (typically every 500 ms). */ 00073 u32_t tcp_ticks; 00074 const u8_t tcp_backoff[13] = 00075 { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7}; 00076 /* Times per slowtmr hits */ 00077 const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 }; 00078 00079 /* The TCP PCB lists. */ 00080 00081 /** List of all TCP PCBs bound but not yet (connected || listening) */ 00082 struct tcp_pcb *tcp_bound_pcbs; 00083 /** List of all TCP PCBs in LISTEN state */ 00084 union tcp_listen_pcbs_t tcp_listen_pcbs; 00085 /** List of all TCP PCBs that are in a state in which 00086 * they accept or send data. */ 00087 struct tcp_pcb *tcp_active_pcbs; 00088 /** List of all TCP PCBs in TIME-WAIT state */ 00089 struct tcp_pcb *tcp_tw_pcbs; 00090 00091 #define NUM_TCP_PCB_LISTS 4 00092 #define NUM_TCP_PCB_LISTS_NO_TIME_WAIT 3 00093 /** An array with all (non-temporary) PCB lists, mainly used for smaller code size */ 00094 struct tcp_pcb ** const tcp_pcb_lists[] = {&tcp_listen_pcbs.pcbs, &tcp_bound_pcbs, 00095 &tcp_active_pcbs, &tcp_tw_pcbs}; 00096 00097 /** Only used for temporary storage. */ 00098 struct tcp_pcb *tcp_tmp_pcb; 00099 00100 /** Timer counter to handle calling slow-timer from tcp_tmr() */ 00101 static u8_t tcp_timer; 00102 static u16_t tcp_new_port(void); 00103 00104 /** 00105 * Called periodically to dispatch TCP timers. 00106 * 00107 */ 00108 void 00109 tcp_tmr(void) 00110 { 00111 /* Call tcp_fasttmr() every 250 ms */ 00112 tcp_fasttmr(); 00113 00114 if (++tcp_timer & 1) { 00115 /* Call tcp_tmr() every 500 ms, i.e., every other timer 00116 tcp_tmr() is called. */ 00117 tcp_slowtmr(); 00118 } 00119 } 00120 00121 /** 00122 * Closes the TX side of a connection held by the PCB. 00123 * For tcp_close(), a RST is sent if the application didn't receive all data 00124 * (tcp_recved() not called for all data passed to recv callback). 00125 * 00126 * Listening pcbs are freed and may not be referenced any more. 00127 * Connection pcbs are freed if not yet connected and may not be referenced 00128 * any more. If a connection is established (at least SYN received or in 00129 * a closing state), the connection is closed, and put in a closing state. 00130 * The pcb is then automatically freed in tcp_slowtmr(). It is therefore 00131 * unsafe to reference it. 00132 * 00133 * @param pcb the tcp_pcb to close 00134 * @return ERR_OK if connection has been closed 00135 * another err_t if closing failed and pcb is not freed 00136 */ 00137 static err_t 00138 tcp_close_shutdown(struct tcp_pcb *pcb, u8_t rst_on_unacked_data) 00139 { 00140 err_t err; 00141 00142 if (rst_on_unacked_data && (pcb->state != LISTEN)) { 00143 if ((pcb->refused_data != NULL) || (pcb->rcv_wnd != TCP_WND)) { 00144 /* Not all data received by application, send RST to tell the remote 00145 side about this. */ 00146 LWIP_ASSERT("pcb->flags & TF_RXCLOSED", pcb->flags & TF_RXCLOSED); 00147 00148 /* don't call tcp_abort here: we must not deallocate the pcb since 00149 that might not be expected when calling tcp_close */ 00150 tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip, 00151 pcb->local_port, pcb->remote_port); 00152 00153 tcp_pcb_purge(pcb); 00154 00155 /* TODO: to which state do we move now? */ 00156 00157 /* move to TIME_WAIT since we close actively */ 00158 TCP_RMV(&tcp_active_pcbs, pcb); 00159 pcb->state = TIME_WAIT; 00160 TCP_REG(&tcp_tw_pcbs, pcb); 00161 00162 return ERR_OK; 00163 } 00164 } 00165 00166 switch (pcb->state) { 00167 case CLOSED: 00168 /* Closing a pcb in the CLOSED state might seem erroneous, 00169 * however, it is in this state once allocated and as yet unused 00170 * and the user needs some way to free it should the need arise. 00171 * Calling tcp_close() with a pcb that has already been closed, (i.e. twice) 00172 * or for a pcb that has been used and then entered the CLOSED state 00173 * is erroneous, but this should never happen as the pcb has in those cases 00174 * been freed, and so any remaining handles are bogus. */ 00175 err = ERR_OK; 00176 if (pcb->local_port != 0) { 00177 TCP_RMV(&tcp_bound_pcbs, pcb); 00178 } 00179 memp_free(MEMP_TCP_PCB, pcb); 00180 pcb = NULL; 00181 break; 00182 case LISTEN: 00183 err = ERR_OK; 00184 tcp_pcb_remove(&tcp_listen_pcbs.pcbs, pcb); 00185 memp_free(MEMP_TCP_PCB_LISTEN, pcb); 00186 pcb = NULL; 00187 break; 00188 case SYN_SENT: 00189 err = ERR_OK; 00190 tcp_pcb_remove(&tcp_active_pcbs, pcb); 00191 memp_free(MEMP_TCP_PCB, pcb); 00192 pcb = NULL; 00193 snmp_inc_tcpattemptfails(); 00194 break; 00195 case SYN_RCVD: 00196 err = tcp_send_fin(pcb); 00197 if (err == ERR_OK) { 00198 snmp_inc_tcpattemptfails(); 00199 pcb->state = FIN_WAIT_1; 00200 } 00201 break; 00202 case ESTABLISHED: 00203 err = tcp_send_fin(pcb); 00204 if (err == ERR_OK) { 00205 snmp_inc_tcpestabresets(); 00206 pcb->state = FIN_WAIT_1; 00207 } 00208 break; 00209 case CLOSE_WAIT: 00210 err = tcp_send_fin(pcb); 00211 if (err == ERR_OK) { 00212 snmp_inc_tcpestabresets(); 00213 pcb->state = LAST_ACK; 00214 } 00215 break; 00216 default: 00217 /* Has already been closed, do nothing. */ 00218 err = ERR_OK; 00219 pcb = NULL; 00220 break; 00221 } 00222 00223 if (pcb != NULL && err == ERR_OK) { 00224 /* To ensure all data has been sent when tcp_close returns, we have 00225 to make sure tcp_output doesn't fail. 00226 Since we don't really have to ensure all data has been sent when tcp_close 00227 returns (unsent data is sent from tcp timer functions, also), we don't care 00228 for the return value of tcp_output for now. */ 00229 /* @todo: When implementing SO_LINGER, this must be changed somehow: 00230 If SOF_LINGER is set, the data should be sent and acked before close returns. 00231 This can only be valid for sequential APIs, not for the raw API. */ 00232 tcp_output(pcb); 00233 } 00234 return err; 00235 } 00236 00237 /** 00238 * Closes the connection held by the PCB. 00239 * 00240 * Listening pcbs are freed and may not be referenced any more. 00241 * Connection pcbs are freed if not yet connected and may not be referenced 00242 * any more. If a connection is established (at least SYN received or in 00243 * a closing state), the connection is closed, and put in a closing state. 00244 * The pcb is then automatically freed in tcp_slowtmr(). It is therefore 00245 * unsafe to reference it (unless an error is returned). 00246 * 00247 * @param pcb the tcp_pcb to close 00248 * @return ERR_OK if connection has been closed 00249 * another err_t if closing failed and pcb is not freed 00250 */ 00251 err_t 00252 tcp_close(struct tcp_pcb *pcb) 00253 { 00254 #if TCP_DEBUG 00255 LWIP_DEBUGF(TCP_DEBUG, ("tcp_close: closing in ")); 00256 tcp_debug_print_state(pcb->state); 00257 #endif /* TCP_DEBUG */ 00258 00259 if (pcb->state != LISTEN) { 00260 /* Set a flag not to receive any more data... */ 00261 pcb->flags |= TF_RXCLOSED; 00262 } 00263 /* ... and close */ 00264 return tcp_close_shutdown(pcb, 1); 00265 } 00266 00267 /** 00268 * Causes all or part of a full-duplex connection of this PCB to be shut down. 00269 * This doesn't deallocate the PCB! 00270 * 00271 * @param pcb PCB to shutdown 00272 * @param shut_rx shut down receive side if this is != 0 00273 * @param shut_tx shut down send side if this is != 0 00274 * @return ERR_OK if shutdown succeeded (or the PCB has already been shut down) 00275 * another err_t on error. 00276 */ 00277 err_t 00278 tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx) 00279 { 00280 if (pcb->state == LISTEN) { 00281 return ERR_CONN; 00282 } 00283 if (shut_rx) { 00284 /* shut down the receive side: free buffered data... */ 00285 if (pcb->refused_data != NULL) { 00286 pbuf_free(pcb->refused_data); 00287 pcb->refused_data = NULL; 00288 } 00289 /* ... and set a flag not to receive any more data */ 00290 pcb->flags |= TF_RXCLOSED; 00291 } 00292 if (shut_tx) { 00293 /* This can't happen twice since if it succeeds, the pcb's state is changed. 00294 Only close in these states as the others directly deallocate the PCB */ 00295 switch (pcb->state) { 00296 case SYN_RCVD: 00297 case ESTABLISHED: 00298 case CLOSE_WAIT: 00299 return tcp_close_shutdown(pcb, 0); 00300 default: 00301 /* don't shut down other states */ 00302 break; 00303 } 00304 } 00305 /* @todo: return another err_t if not in correct state or already shut? */ 00306 return ERR_OK; 00307 } 00308 00309 /** 00310 * Abandons a connection and optionally sends a RST to the remote 00311 * host. Deletes the local protocol control block. This is done when 00312 * a connection is killed because of shortage of memory. 00313 * 00314 * @param pcb the tcp_pcb to abort 00315 * @param reset boolean to indicate whether a reset should be sent 00316 */ 00317 void 00318 tcp_abandon(struct tcp_pcb *pcb, int reset) 00319 { 00320 u32_t seqno, ackno; 00321 u16_t remote_port, local_port; 00322 ip_addr_t remote_ip, local_ip; 00323 #if LWIP_CALLBACK_API 00324 tcp_err_fn errf; 00325 #endif /* LWIP_CALLBACK_API */ 00326 void *errf_arg; 00327 00328 /* pcb->state LISTEN not allowed here */ 00329 LWIP_ASSERT("don't call tcp_abort/tcp_abandon for listen-pcbs", 00330 pcb->state != LISTEN); 00331 /* Figure out on which TCP PCB list we are, and remove us. If we 00332 are in an active state, call the receive function associated with 00333 the PCB with a NULL argument, and send an RST to the remote end. */ 00334 if (pcb->state == TIME_WAIT) { 00335 tcp_pcb_remove(&tcp_tw_pcbs, pcb); 00336 memp_free(MEMP_TCP_PCB, pcb); 00337 } else { 00338 seqno = pcb->snd_nxt; 00339 ackno = pcb->rcv_nxt; 00340 ip_addr_copy(local_ip, pcb->local_ip); 00341 ip_addr_copy(remote_ip, pcb->remote_ip); 00342 local_port = pcb->local_port; 00343 remote_port = pcb->remote_port; 00344 #if LWIP_CALLBACK_API 00345 errf = pcb->errf; 00346 #endif /* LWIP_CALLBACK_API */ 00347 errf_arg = pcb->callback_arg; 00348 tcp_pcb_remove(&tcp_active_pcbs, pcb); 00349 if (pcb->unacked != NULL) { 00350 tcp_segs_free(pcb->unacked); 00351 } 00352 if (pcb->unsent != NULL) { 00353 tcp_segs_free(pcb->unsent); 00354 } 00355 #if TCP_QUEUE_OOSEQ 00356 if (pcb->ooseq != NULL) { 00357 tcp_segs_free(pcb->ooseq); 00358 } 00359 #endif /* TCP_QUEUE_OOSEQ */ 00360 memp_free(MEMP_TCP_PCB, pcb); 00361 TCP_EVENT_ERR(errf, errf_arg, ERR_ABRT); 00362 if (reset) { 00363 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_abandon: sending RST\n")); 00364 tcp_rst(seqno, ackno, &local_ip, &remote_ip, local_port, remote_port); 00365 } 00366 } 00367 } 00368 00369 /** 00370 * Aborts the connection by sending a RST (reset) segment to the remote 00371 * host. The pcb is deallocated. This function never fails. 00372 * 00373 * ATTENTION: When calling this from one of the TCP callbacks, make 00374 * sure you always return ERR_ABRT (and never return ERR_ABRT otherwise 00375 * or you will risk accessing deallocated memory or memory leaks! 00376 * 00377 * @param pcb the tcp pcb to abort 00378 */ 00379 void 00380 tcp_abort(struct tcp_pcb *pcb) 00381 { 00382 tcp_abandon(pcb, 1); 00383 } 00384 00385 /** 00386 * Binds the connection to a local portnumber and IP address. If the 00387 * IP address is not given (i.e., ipaddr == NULL), the IP address of 00388 * the outgoing network interface is used instead. 00389 * 00390 * @param pcb the tcp_pcb to bind (no check is done whether this pcb is 00391 * already bound!) 00392 * @param ipaddr the local ip address to bind to (use IP_ADDR_ANY to bind 00393 * to any local address 00394 * @param port the local port to bind to 00395 * @return ERR_USE if the port is already in use 00396 * ERR_VAL if bind failed because the PCB is not in a valid state 00397 * ERR_OK if bound 00398 */ 00399 err_t 00400 tcp_bind(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port) 00401 { 00402 int i; 00403 int max_pcb_list = NUM_TCP_PCB_LISTS; 00404 struct tcp_pcb *cpcb; 00405 00406 LWIP_ERROR("tcp_bind: can only bind in state CLOSED", pcb->state == CLOSED, return ERR_VAL); 00407 00408 #if SO_REUSE 00409 /* Unless the REUSEADDR flag is set, 00410 we have to check the pcbs in TIME-WAIT state, also. 00411 We do not dump TIME_WAIT pcb's; they can still be matched by incoming 00412 packets using both local and remote IP addresses and ports to distinguish. 00413 */ 00414 if ((pcb->so_options & SOF_REUSEADDR) != 0) { 00415 max_pcb_list = NUM_TCP_PCB_LISTS_NO_TIME_WAIT; 00416 } 00417 #endif /* SO_REUSE */ 00418 00419 if (port == 0) { 00420 port = tcp_new_port(); 00421 } 00422 00423 /* Check if the address already is in use (on all lists) */ 00424 for (i = 0; i < max_pcb_list; i++) { 00425 for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) { 00426 if (cpcb->local_port == port) { 00427 #if SO_REUSE 00428 /* Omit checking for the same port if both pcbs have REUSEADDR set. 00429 For SO_REUSEADDR, the duplicate-check for a 5-tuple is done in 00430 tcp_connect. */ 00431 if (((pcb->so_options & SOF_REUSEADDR) == 0) || 00432 ((cpcb->so_options & SOF_REUSEADDR) == 0)) 00433 #endif /* SO_REUSE */ 00434 { 00435 if (ip_addr_isany(&(cpcb->local_ip)) || 00436 ip_addr_isany(ipaddr) || 00437 ip_addr_cmp(&(cpcb->local_ip), ipaddr)) { 00438 return ERR_USE; 00439 } 00440 } 00441 } 00442 } 00443 } 00444 00445 if (!ip_addr_isany(ipaddr)) { 00446 pcb->local_ip = *ipaddr; 00447 } 00448 pcb->local_port = port; 00449 TCP_REG(&tcp_bound_pcbs, pcb); 00450 LWIP_DEBUGF(TCP_DEBUG, ("tcp_bind: bind to port %"U16_F"\n", port)); 00451 return ERR_OK; 00452 } 00453 #if LWIP_CALLBACK_API 00454 /** 00455 * Default accept callback if no accept callback is specified by the user. 00456 */ 00457 static err_t 00458 tcp_accept_null(void *arg, struct tcp_pcb *pcb, err_t err) 00459 { 00460 LWIP_UNUSED_ARG(arg); 00461 LWIP_UNUSED_ARG(pcb); 00462 LWIP_UNUSED_ARG(err); 00463 00464 return ERR_ABRT; 00465 } 00466 #endif /* LWIP_CALLBACK_API */ 00467 00468 /** 00469 * Set the state of the connection to be LISTEN, which means that it 00470 * is able to accept incoming connections. The protocol control block 00471 * is reallocated in order to consume less memory. Setting the 00472 * connection to LISTEN is an irreversible process. 00473 * 00474 * @param pcb the original tcp_pcb 00475 * @param backlog the incoming connections queue limit 00476 * @return tcp_pcb used for listening, consumes less memory. 00477 * 00478 * @note The original tcp_pcb is freed. This function therefore has to be 00479 * called like this: 00480 * tpcb = tcp_listen(tpcb); 00481 */ 00482 struct tcp_pcb * 00483 tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog) 00484 { 00485 struct tcp_pcb_listen *lpcb; 00486 00487 LWIP_UNUSED_ARG(backlog); 00488 LWIP_ERROR("tcp_listen: pcb already connected", pcb->state == CLOSED, return NULL); 00489 00490 /* already listening? */ 00491 if (pcb->state == LISTEN) { 00492 return pcb; 00493 } 00494 #if SO_REUSE 00495 if ((pcb->so_options & SOF_REUSEADDR) != 0) { 00496 /* Since SOF_REUSEADDR allows reusing a local address before the pcb's usage 00497 is declared (listen-/connection-pcb), we have to make sure now that 00498 this port is only used once for every local IP. */ 00499 for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) { 00500 if (lpcb->local_port == pcb->local_port) { 00501 if (ip_addr_cmp(&lpcb->local_ip, &pcb->local_ip)) { 00502 /* this address/port is already used */ 00503 return NULL; 00504 } 00505 } 00506 } 00507 } 00508 #endif /* SO_REUSE */ 00509 lpcb = (struct tcp_pcb_listen *)memp_malloc(MEMP_TCP_PCB_LISTEN); 00510 if (lpcb == NULL) { 00511 return NULL; 00512 } 00513 lpcb->callback_arg = pcb->callback_arg; 00514 lpcb->local_port = pcb->local_port; 00515 lpcb->state = LISTEN; 00516 lpcb->prio = pcb->prio; 00517 lpcb->so_options = pcb->so_options; 00518 lpcb->so_options |= SOF_ACCEPTCONN; 00519 lpcb->ttl = pcb->ttl; 00520 lpcb->tos = pcb->tos; 00521 ip_addr_copy(lpcb->local_ip, pcb->local_ip); 00522 if (pcb->local_port != 0) { 00523 TCP_RMV(&tcp_bound_pcbs, pcb); 00524 } 00525 memp_free(MEMP_TCP_PCB, pcb); 00526 #if LWIP_CALLBACK_API 00527 lpcb->accept = tcp_accept_null; 00528 #endif /* LWIP_CALLBACK_API */ 00529 #if TCP_LISTEN_BACKLOG 00530 lpcb->accepts_pending = 0; 00531 lpcb->backlog = (backlog ? backlog : 1); 00532 #endif /* TCP_LISTEN_BACKLOG */ 00533 TCP_REG(&tcp_listen_pcbs.pcbs, (struct tcp_pcb *)lpcb); 00534 return (struct tcp_pcb *)lpcb; 00535 } 00536 00537 /** 00538 * Update the state that tracks the available window space to advertise. 00539 * 00540 * Returns how much extra window would be advertised if we sent an 00541 * update now. 00542 */ 00543 u32_t tcp_update_rcv_ann_wnd(struct tcp_pcb *pcb) 00544 { 00545 u32_t new_right_edge = pcb->rcv_nxt + pcb->rcv_wnd; 00546 00547 if (TCP_SEQ_GEQ(new_right_edge, pcb->rcv_ann_right_edge + LWIP_MIN((TCP_WND / 2), pcb->mss))) { 00548 /* we can advertise more window */ 00549 pcb->rcv_ann_wnd = pcb->rcv_wnd; 00550 return new_right_edge - pcb->rcv_ann_right_edge; 00551 } else { 00552 if (TCP_SEQ_GT(pcb->rcv_nxt, pcb->rcv_ann_right_edge)) { 00553 /* Can happen due to other end sending out of advertised window, 00554 * but within actual available (but not yet advertised) window */ 00555 pcb->rcv_ann_wnd = 0; 00556 } else { 00557 /* keep the right edge of window constant */ 00558 u32_t new_rcv_ann_wnd = pcb->rcv_ann_right_edge - pcb->rcv_nxt; 00559 LWIP_ASSERT("new_rcv_ann_wnd <= 0xffff", new_rcv_ann_wnd <= 0xffff); 00560 pcb->rcv_ann_wnd = (u16_t)new_rcv_ann_wnd; 00561 } 00562 return 0; 00563 } 00564 } 00565 00566 /** 00567 * This function should be called by the application when it has 00568 * processed the data. The purpose is to advertise a larger window 00569 * when the data has been processed. 00570 * 00571 * @param pcb the tcp_pcb for which data is read 00572 * @param len the amount of bytes that have been read by the application 00573 */ 00574 void 00575 tcp_recved(struct tcp_pcb *pcb, u16_t len) 00576 { 00577 int wnd_inflation; 00578 00579 LWIP_ASSERT("tcp_recved: len would wrap rcv_wnd\n", 00580 len <= 0xffff - pcb->rcv_wnd ); 00581 00582 pcb->rcv_wnd += len; 00583 if (pcb->rcv_wnd > TCP_WND) { 00584 pcb->rcv_wnd = TCP_WND; 00585 } 00586 00587 wnd_inflation = tcp_update_rcv_ann_wnd(pcb); 00588 00589 /* If the change in the right edge of window is significant (default 00590 * watermark is TCP_WND/4), then send an explicit update now. 00591 * Otherwise wait for a packet to be sent in the normal course of 00592 * events (or more window to be available later) */ 00593 if (wnd_inflation >= TCP_WND_UPDATE_THRESHOLD) { 00594 tcp_ack_now(pcb); 00595 tcp_output(pcb); 00596 } 00597 00598 LWIP_DEBUGF(TCP_DEBUG, ("tcp_recved: recveived %"U16_F" bytes, wnd %"U16_F" (%"U16_F").\n", 00599 len, pcb->rcv_wnd, TCP_WND - pcb->rcv_wnd)); 00600 } 00601 00602 /** 00603 * A nastly hack featuring 'goto' statements that allocates a 00604 * new TCP local port. 00605 * 00606 * @return a new (free) local TCP port number 00607 */ 00608 static u16_t 00609 tcp_new_port(void) 00610 { 00611 int i; 00612 struct tcp_pcb *pcb; 00613 #ifndef TCP_LOCAL_PORT_RANGE_START 00614 /* From http://www.iana.org/assignments/port-numbers: 00615 "The Dynamic and/or Private Ports are those from 49152 through 65535" */ 00616 #define TCP_LOCAL_PORT_RANGE_START 0xc000 00617 #define TCP_LOCAL_PORT_RANGE_END 0xffff 00618 #endif 00619 static u16_t port = TCP_LOCAL_PORT_RANGE_START; 00620 00621 again: 00622 if (port++ >= TCP_LOCAL_PORT_RANGE_END) { 00623 port = TCP_LOCAL_PORT_RANGE_START; 00624 } 00625 /* Check all PCB lists. */ 00626 for (i = 0; i < NUM_TCP_PCB_LISTS; i++) { 00627 for(pcb = *tcp_pcb_lists[i]; pcb != NULL; pcb = pcb->next) { 00628 if (pcb->local_port == port) { 00629 goto again; 00630 } 00631 } 00632 } 00633 return port; 00634 } 00635 00636 /** 00637 * Connects to another host. The function given as the "connected" 00638 * argument will be called when the connection has been established. 00639 * 00640 * @param pcb the tcp_pcb used to establish the connection 00641 * @param ipaddr the remote ip address to connect to 00642 * @param port the remote tcp port to connect to 00643 * @param connected callback function to call when connected (or on error) 00644 * @return ERR_VAL if invalid arguments are given 00645 * ERR_OK if connect request has been sent 00646 * other err_t values if connect request couldn't be sent 00647 */ 00648 err_t 00649 tcp_connect(struct tcp_pcb *pcb, ip_addr_t *ipaddr, u16_t port, 00650 tcp_connected_fn connected) 00651 { 00652 err_t ret; 00653 u32_t iss; 00654 u16_t old_local_port; 00655 00656 LWIP_ERROR("tcp_connect: can only connect from state CLOSED", pcb->state == CLOSED, return ERR_ISCONN); 00657 00658 LWIP_DEBUGF(TCP_DEBUG, ("tcp_connect to port %"U16_F"\n", port)); 00659 if (ipaddr != NULL) { 00660 pcb->remote_ip = *ipaddr; 00661 } else { 00662 return ERR_VAL; 00663 } 00664 pcb->remote_port = port; 00665 00666 /* check if we have a route to the remote host */ 00667 if (ip_addr_isany(&(pcb->local_ip))) { 00668 /* no local IP address set, yet. */ 00669 struct netif *netif = ip_route(&(pcb->remote_ip)); 00670 if (netif == NULL) { 00671 /* Don't even try to send a SYN packet if we have no route 00672 since that will fail. */ 00673 return ERR_RTE; 00674 } 00675 /* Use the netif's IP address as local address. */ 00676 ip_addr_copy(pcb->local_ip, netif->ip_addr); 00677 } 00678 00679 old_local_port = pcb->local_port; 00680 if (pcb->local_port == 0) { 00681 pcb->local_port = tcp_new_port(); 00682 } 00683 #if SO_REUSE 00684 if ((pcb->so_options & SOF_REUSEADDR) != 0) { 00685 /* Since SOF_REUSEADDR allows reusing a local address, we have to make sure 00686 now that the 5-tuple is unique. */ 00687 struct tcp_pcb *cpcb; 00688 int i; 00689 /* Don't check listen- and bound-PCBs, check active- and TIME-WAIT PCBs. */ 00690 for (i = 2; i < NUM_TCP_PCB_LISTS; i++) { 00691 for(cpcb = *tcp_pcb_lists[i]; cpcb != NULL; cpcb = cpcb->next) { 00692 if ((cpcb->local_port == pcb->local_port) && 00693 (cpcb->remote_port == port) && 00694 ip_addr_cmp(&cpcb->local_ip, &pcb->local_ip) && 00695 ip_addr_cmp(&cpcb->remote_ip, ipaddr)) { 00696 /* linux returns EISCONN here, but ERR_USE should be OK for us */ 00697 return ERR_USE; 00698 } 00699 } 00700 } 00701 } 00702 #endif /* SO_REUSE */ 00703 iss = tcp_next_iss(); 00704 pcb->rcv_nxt = 0; 00705 pcb->snd_nxt = iss; 00706 pcb->lastack = iss - 1; 00707 pcb->snd_lbb = iss - 1; 00708 pcb->rcv_wnd = TCP_WND; 00709 pcb->rcv_ann_wnd = TCP_WND; 00710 pcb->rcv_ann_right_edge = pcb->rcv_nxt; 00711 pcb->snd_wnd = TCP_WND; 00712 /* As initial send MSS, we use TCP_MSS but limit it to 536. 00713 The send MSS is updated when an MSS option is received. */ 00714 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS; 00715 #if TCP_CALCULATE_EFF_SEND_MSS 00716 pcb->mss = tcp_eff_send_mss(pcb->mss, ipaddr); 00717 #endif /* TCP_CALCULATE_EFF_SEND_MSS */ 00718 pcb->cwnd = 1; 00719 pcb->ssthresh = pcb->mss * 10; 00720 #if LWIP_CALLBACK_API 00721 pcb->connected = connected; 00722 #else /* LWIP_CALLBACK_API */ 00723 LWIP_UNUSED_ARG(connected); 00724 #endif /* LWIP_CALLBACK_API */ 00725 00726 /* Send a SYN together with the MSS option. */ 00727 ret = tcp_enqueue_flags(pcb, TCP_SYN); 00728 if (ret == ERR_OK) { 00729 /* SYN segment was enqueued, changed the pcbs state now */ 00730 pcb->state = SYN_SENT; 00731 if (old_local_port != 0) { 00732 TCP_RMV(&tcp_bound_pcbs, pcb); 00733 } 00734 TCP_REG(&tcp_active_pcbs, pcb); 00735 snmp_inc_tcpactiveopens(); 00736 00737 tcp_output(pcb); 00738 } 00739 return ret; 00740 } 00741 00742 /** 00743 * Called every 500 ms and implements the retransmission timer and the timer that 00744 * removes PCBs that have been in TIME-WAIT for enough time. It also increments 00745 * various timers such as the inactivity timer in each PCB. 00746 * 00747 * Automatically called from tcp_tmr(). 00748 */ 00749 void 00750 tcp_slowtmr(void) 00751 { 00752 struct tcp_pcb *pcb, *prev; 00753 u16_t eff_wnd; 00754 u8_t pcb_remove; /* flag if a PCB should be removed */ 00755 u8_t pcb_reset; /* flag if a RST should be sent when removing */ 00756 err_t err; 00757 00758 err = ERR_OK; 00759 00760 ++tcp_ticks; 00761 00762 /* Steps through all of the active PCBs. */ 00763 prev = NULL; 00764 pcb = tcp_active_pcbs; 00765 if (pcb == NULL) { 00766 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: no active pcbs\n")); 00767 } 00768 while (pcb != NULL) { 00769 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: processing active pcb\n")); 00770 LWIP_ASSERT("tcp_slowtmr: active pcb->state != CLOSED\n", pcb->state != CLOSED); 00771 LWIP_ASSERT("tcp_slowtmr: active pcb->state != LISTEN\n", pcb->state != LISTEN); 00772 LWIP_ASSERT("tcp_slowtmr: active pcb->state != TIME-WAIT\n", pcb->state != TIME_WAIT); 00773 00774 pcb_remove = 0; 00775 pcb_reset = 0; 00776 00777 if (pcb->state == SYN_SENT && pcb->nrtx == TCP_SYNMAXRTX) { 00778 ++pcb_remove; 00779 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max SYN retries reached\n")); 00780 } 00781 else if (pcb->nrtx == TCP_MAXRTX) { 00782 ++pcb_remove; 00783 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: max DATA retries reached\n")); 00784 } else { 00785 if (pcb->persist_backoff > 0) { 00786 /* If snd_wnd is zero, use persist timer to send 1 byte probes 00787 * instead of using the standard retransmission mechanism. */ 00788 pcb->persist_cnt++; 00789 if (pcb->persist_cnt >= tcp_persist_backoff[pcb->persist_backoff-1]) { 00790 pcb->persist_cnt = 0; 00791 if (pcb->persist_backoff < sizeof(tcp_persist_backoff)) { 00792 pcb->persist_backoff++; 00793 } 00794 tcp_zero_window_probe(pcb); 00795 } 00796 } else { 00797 /* Increase the retransmission timer if it is running */ 00798 if(pcb->rtime >= 0) 00799 ++pcb->rtime; 00800 00801 if (pcb->unacked != NULL && pcb->rtime >= pcb->rto) { 00802 /* Time for a retransmission. */ 00803 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_slowtmr: rtime %"S16_F 00804 " pcb->rto %"S16_F"\n", 00805 pcb->rtime, pcb->rto)); 00806 00807 /* Double retransmission time-out unless we are trying to 00808 * connect to somebody (i.e., we are in SYN_SENT). */ 00809 if (pcb->state != SYN_SENT) { 00810 pcb->rto = ((pcb->sa >> 3) + pcb->sv) << tcp_backoff[pcb->nrtx]; 00811 } 00812 00813 /* Reset the retransmission timer. */ 00814 pcb->rtime = 0; 00815 00816 /* Reduce congestion window and ssthresh. */ 00817 eff_wnd = LWIP_MIN(pcb->cwnd, pcb->snd_wnd); 00818 pcb->ssthresh = eff_wnd >> 1; 00819 if (pcb->ssthresh < (pcb->mss << 1)) { 00820 pcb->ssthresh = (pcb->mss << 1); 00821 } 00822 pcb->cwnd = pcb->mss; 00823 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: cwnd %"U16_F 00824 " ssthresh %"U16_F"\n", 00825 pcb->cwnd, pcb->ssthresh)); 00826 00827 /* The following needs to be called AFTER cwnd is set to one 00828 mss - STJ */ 00829 tcp_rexmit_rto(pcb); 00830 } 00831 } 00832 } 00833 /* Check if this PCB has stayed too long in FIN-WAIT-2 */ 00834 if (pcb->state == FIN_WAIT_2) { 00835 if ((u32_t)(tcp_ticks - pcb->tmr) > 00836 TCP_FIN_WAIT_TIMEOUT / TCP_SLOW_INTERVAL) { 00837 ++pcb_remove; 00838 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in FIN-WAIT-2\n")); 00839 } 00840 } 00841 00842 /* Check if KEEPALIVE should be sent */ 00843 if((pcb->so_options & SOF_KEEPALIVE) && 00844 ((pcb->state == ESTABLISHED) || 00845 (pcb->state == CLOSE_WAIT))) { 00846 #if LWIP_TCP_KEEPALIVE 00847 if((u32_t)(tcp_ticks - pcb->tmr) > 00848 (pcb->keep_idle + (pcb->keep_cnt*pcb->keep_intvl)) 00849 / TCP_SLOW_INTERVAL) 00850 #else 00851 if((u32_t)(tcp_ticks - pcb->tmr) > 00852 (pcb->keep_idle + TCP_MAXIDLE) / TCP_SLOW_INTERVAL) 00853 #endif /* LWIP_TCP_KEEPALIVE */ 00854 { 00855 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: KEEPALIVE timeout. Aborting connection to %"U16_F".%"U16_F".%"U16_F".%"U16_F".\n", 00856 ip4_addr1_16(&pcb->remote_ip), ip4_addr2_16(&pcb->remote_ip), 00857 ip4_addr3_16(&pcb->remote_ip), ip4_addr4_16(&pcb->remote_ip))); 00858 00859 ++pcb_remove; 00860 ++pcb_reset; 00861 } 00862 #if LWIP_TCP_KEEPALIVE 00863 else if((u32_t)(tcp_ticks - pcb->tmr) > 00864 (pcb->keep_idle + pcb->keep_cnt_sent * pcb->keep_intvl) 00865 / TCP_SLOW_INTERVAL) 00866 #else 00867 else if((u32_t)(tcp_ticks - pcb->tmr) > 00868 (pcb->keep_idle + pcb->keep_cnt_sent * TCP_KEEPINTVL_DEFAULT) 00869 / TCP_SLOW_INTERVAL) 00870 #endif /* LWIP_TCP_KEEPALIVE */ 00871 { 00872 tcp_keepalive(pcb); 00873 pcb->keep_cnt_sent++; 00874 } 00875 } 00876 00877 /* If this PCB has queued out of sequence data, but has been 00878 inactive for too long, will drop the data (it will eventually 00879 be retransmitted). */ 00880 #if TCP_QUEUE_OOSEQ 00881 if (pcb->ooseq != NULL && 00882 (u32_t)tcp_ticks - pcb->tmr >= pcb->rto * TCP_OOSEQ_TIMEOUT) { 00883 tcp_segs_free(pcb->ooseq); 00884 pcb->ooseq = NULL; 00885 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_slowtmr: dropping OOSEQ queued data\n")); 00886 } 00887 #endif /* TCP_QUEUE_OOSEQ */ 00888 00889 /* Check if this PCB has stayed too long in SYN-RCVD */ 00890 if (pcb->state == SYN_RCVD) { 00891 if ((u32_t)(tcp_ticks - pcb->tmr) > 00892 TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) { 00893 ++pcb_remove; 00894 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in SYN-RCVD\n")); 00895 } 00896 } 00897 00898 /* Check if this PCB has stayed too long in LAST-ACK */ 00899 if (pcb->state == LAST_ACK) { 00900 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) { 00901 ++pcb_remove; 00902 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: removing pcb stuck in LAST-ACK\n")); 00903 } 00904 } 00905 00906 /* If the PCB should be removed, do it. */ 00907 if (pcb_remove) { 00908 struct tcp_pcb *pcb2; 00909 tcp_pcb_purge(pcb); 00910 /* Remove PCB from tcp_active_pcbs list. */ 00911 if (prev != NULL) { 00912 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_active_pcbs", pcb != tcp_active_pcbs); 00913 prev->next = pcb->next; 00914 } else { 00915 /* This PCB was the first. */ 00916 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_active_pcbs", tcp_active_pcbs == pcb); 00917 tcp_active_pcbs = pcb->next; 00918 } 00919 00920 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_ABRT); 00921 if (pcb_reset) { 00922 tcp_rst(pcb->snd_nxt, pcb->rcv_nxt, &pcb->local_ip, &pcb->remote_ip, 00923 pcb->local_port, pcb->remote_port); 00924 } 00925 00926 pcb2 = pcb; 00927 pcb = pcb->next; 00928 memp_free(MEMP_TCP_PCB, pcb2); 00929 } else { 00930 /* get the 'next' element now and work with 'prev' below (in case of abort) */ 00931 prev = pcb; 00932 pcb = pcb->next; 00933 00934 /* We check if we should poll the connection. */ 00935 ++prev->polltmr; 00936 if (prev->polltmr >= prev->pollinterval) { 00937 prev->polltmr = 0; 00938 LWIP_DEBUGF(TCP_DEBUG, ("tcp_slowtmr: polling application\n")); 00939 TCP_EVENT_POLL(prev, err); 00940 /* if err == ERR_ABRT, 'prev' is already deallocated */ 00941 if (err == ERR_OK) { 00942 tcp_output(prev); 00943 } 00944 } 00945 } 00946 } 00947 00948 00949 /* Steps through all of the TIME-WAIT PCBs. */ 00950 prev = NULL; 00951 pcb = tcp_tw_pcbs; 00952 while (pcb != NULL) { 00953 LWIP_ASSERT("tcp_slowtmr: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT); 00954 pcb_remove = 0; 00955 00956 /* Check if this PCB has stayed long enough in TIME-WAIT */ 00957 if ((u32_t)(tcp_ticks - pcb->tmr) > 2 * TCP_MSL / TCP_SLOW_INTERVAL) { 00958 ++pcb_remove; 00959 } 00960 00961 00962 00963 /* If the PCB should be removed, do it. */ 00964 if (pcb_remove) { 00965 struct tcp_pcb *pcb2; 00966 tcp_pcb_purge(pcb); 00967 /* Remove PCB from tcp_tw_pcbs list. */ 00968 if (prev != NULL) { 00969 LWIP_ASSERT("tcp_slowtmr: middle tcp != tcp_tw_pcbs", pcb != tcp_tw_pcbs); 00970 prev->next = pcb->next; 00971 } else { 00972 /* This PCB was the first. */ 00973 LWIP_ASSERT("tcp_slowtmr: first pcb == tcp_tw_pcbs", tcp_tw_pcbs == pcb); 00974 tcp_tw_pcbs = pcb->next; 00975 } 00976 pcb2 = pcb; 00977 pcb = pcb->next; 00978 memp_free(MEMP_TCP_PCB, pcb2); 00979 } else { 00980 prev = pcb; 00981 pcb = pcb->next; 00982 } 00983 } 00984 } 00985 00986 /** 00987 * Is called every TCP_FAST_INTERVAL (250 ms) and process data previously 00988 * "refused" by upper layer (application) and sends delayed ACKs. 00989 * 00990 * Automatically called from tcp_tmr(). 00991 */ 00992 void 00993 tcp_fasttmr(void) 00994 { 00995 struct tcp_pcb *pcb = tcp_active_pcbs; 00996 00997 while(pcb != NULL) { 00998 struct tcp_pcb *next = pcb->next; 00999 /* If there is data which was previously "refused" by upper layer */ 01000 if (pcb->refused_data != NULL) { 01001 /* Notify again application with data previously received. */ 01002 err_t err; 01003 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_fasttmr: notify kept packet\n")); 01004 TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err); 01005 if (err == ERR_OK) { 01006 pcb->refused_data = NULL; 01007 } else if (err == ERR_ABRT) { 01008 /* if err == ERR_ABRT, 'pcb' is already deallocated */ 01009 pcb = NULL; 01010 } 01011 } 01012 01013 /* send delayed ACKs */ 01014 if (pcb && (pcb->flags & TF_ACK_DELAY)) { 01015 LWIP_DEBUGF(TCP_DEBUG, ("tcp_fasttmr: delayed ACK\n")); 01016 tcp_ack_now(pcb); 01017 tcp_output(pcb); 01018 pcb->flags &= ~(TF_ACK_DELAY | TF_ACK_NOW); 01019 } 01020 01021 pcb = next; 01022 } 01023 } 01024 01025 /** 01026 * Deallocates a list of TCP segments (tcp_seg structures). 01027 * 01028 * @param seg tcp_seg list of TCP segments to free 01029 */ 01030 void 01031 tcp_segs_free(struct tcp_seg *seg) 01032 { 01033 while (seg != NULL) { 01034 struct tcp_seg *next = seg->next; 01035 tcp_seg_free(seg); 01036 seg = next; 01037 } 01038 } 01039 01040 /** 01041 * Frees a TCP segment (tcp_seg structure). 01042 * 01043 * @param seg single tcp_seg to free 01044 */ 01045 void 01046 tcp_seg_free(struct tcp_seg *seg) 01047 { 01048 if (seg != NULL) { 01049 if (seg->p != NULL) { 01050 pbuf_free(seg->p); 01051 #if TCP_DEBUG 01052 seg->p = NULL; 01053 #endif /* TCP_DEBUG */ 01054 } 01055 memp_free(MEMP_TCP_SEG, seg); 01056 } 01057 } 01058 01059 /** 01060 * Sets the priority of a connection. 01061 * 01062 * @param pcb the tcp_pcb to manipulate 01063 * @param prio new priority 01064 */ 01065 void 01066 tcp_setprio(struct tcp_pcb *pcb, u8_t prio) 01067 { 01068 pcb->prio = prio; 01069 } 01070 01071 #if TCP_QUEUE_OOSEQ 01072 /** 01073 * Returns a copy of the given TCP segment. 01074 * The pbuf and data are not copied, only the pointers 01075 * 01076 * @param seg the old tcp_seg 01077 * @return a copy of seg 01078 */ 01079 struct tcp_seg * 01080 tcp_seg_copy(struct tcp_seg *seg) 01081 { 01082 struct tcp_seg *cseg; 01083 01084 cseg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG); 01085 if (cseg == NULL) { 01086 return NULL; 01087 } 01088 SMEMCPY((u8_t *)cseg, (const u8_t *)seg, sizeof(struct tcp_seg)); 01089 pbuf_ref(cseg->p); 01090 return cseg; 01091 } 01092 #endif /* TCP_QUEUE_OOSEQ */ 01093 01094 #if LWIP_CALLBACK_API 01095 /** 01096 * Default receive callback that is called if the user didn't register 01097 * a recv callback for the pcb. 01098 */ 01099 err_t 01100 tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) 01101 { 01102 LWIP_UNUSED_ARG(arg); 01103 if (p != NULL) { 01104 tcp_recved(pcb, p->tot_len); 01105 pbuf_free(p); 01106 } else if (err == ERR_OK) { 01107 return tcp_close(pcb); 01108 } 01109 return ERR_OK; 01110 } 01111 #endif /* LWIP_CALLBACK_API */ 01112 01113 /** 01114 * Kills the oldest active connection that has lower priority than prio. 01115 * 01116 * @param prio minimum priority 01117 */ 01118 static void 01119 tcp_kill_prio(u8_t prio) 01120 { 01121 struct tcp_pcb *pcb, *inactive; 01122 u32_t inactivity; 01123 u8_t mprio; 01124 01125 01126 mprio = TCP_PRIO_MAX; 01127 01128 /* We kill the oldest active connection that has lower priority than prio. */ 01129 inactivity = 0; 01130 inactive = NULL; 01131 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { 01132 if (pcb->prio <= prio && 01133 pcb->prio <= mprio && 01134 (u32_t)(tcp_ticks - pcb->tmr) >= inactivity) { 01135 inactivity = tcp_ticks - pcb->tmr; 01136 inactive = pcb; 01137 mprio = pcb->prio; 01138 } 01139 } 01140 if (inactive != NULL) { 01141 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_prio: killing oldest PCB %p (%"S32_F")\n", 01142 (void *)inactive, inactivity)); 01143 tcp_abort(inactive); 01144 } 01145 } 01146 01147 /** 01148 * Kills the oldest connection that is in TIME_WAIT state. 01149 * Called from tcp_alloc() if no more connections are available. 01150 */ 01151 static void 01152 tcp_kill_timewait(void) 01153 { 01154 struct tcp_pcb *pcb, *inactive; 01155 u32_t inactivity; 01156 01157 inactivity = 0; 01158 inactive = NULL; 01159 /* Go through the list of TIME_WAIT pcbs and get the oldest pcb. */ 01160 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) { 01161 if ((u32_t)(tcp_ticks - pcb->tmr) >= inactivity) { 01162 inactivity = tcp_ticks - pcb->tmr; 01163 inactive = pcb; 01164 } 01165 } 01166 if (inactive != NULL) { 01167 LWIP_DEBUGF(TCP_DEBUG, ("tcp_kill_timewait: killing oldest TIME-WAIT PCB %p (%"S32_F")\n", 01168 (void *)inactive, inactivity)); 01169 tcp_abort(inactive); 01170 } 01171 } 01172 01173 /** 01174 * Allocate a new tcp_pcb structure. 01175 * 01176 * @param prio priority for the new pcb 01177 * @return a new tcp_pcb that initially is in state CLOSED 01178 */ 01179 struct tcp_pcb * 01180 tcp_alloc(u8_t prio) 01181 { 01182 struct tcp_pcb *pcb; 01183 u32_t iss; 01184 01185 pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); 01186 if (pcb == NULL) { 01187 /* Try killing oldest connection in TIME-WAIT. */ 01188 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest TIME-WAIT connection\n")); 01189 tcp_kill_timewait(); 01190 /* Try to allocate a tcp_pcb again. */ 01191 pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); 01192 if (pcb == NULL) { 01193 /* Try killing active connections with lower priority than the new one. */ 01194 LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing connection with prio lower than %d\n", prio)); 01195 tcp_kill_prio(prio); 01196 /* Try to allocate a tcp_pcb again. */ 01197 pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB); 01198 if (pcb != NULL) { 01199 /* adjust err stats: memp_malloc failed twice before */ 01200 MEMP_STATS_DEC(err, MEMP_TCP_PCB); 01201 } 01202 } 01203 if (pcb != NULL) { 01204 /* adjust err stats: timewait PCB was freed above */ 01205 MEMP_STATS_DEC(err, MEMP_TCP_PCB); 01206 } 01207 } 01208 if (pcb != NULL) { 01209 memset(pcb, 0, sizeof(struct tcp_pcb)); 01210 pcb->prio = prio; 01211 pcb->snd_buf = TCP_SND_BUF; 01212 pcb->snd_queuelen = 0; 01213 pcb->rcv_wnd = TCP_WND; 01214 pcb->rcv_ann_wnd = TCP_WND; 01215 pcb->tos = 0; 01216 pcb->ttl = TCP_TTL; 01217 /* As initial send MSS, we use TCP_MSS but limit it to 536. 01218 The send MSS is updated when an MSS option is received. */ 01219 pcb->mss = (TCP_MSS > 536) ? 536 : TCP_MSS; 01220 pcb->rto = 3000 / TCP_SLOW_INTERVAL; 01221 pcb->sa = 0; 01222 pcb->sv = 3000 / TCP_SLOW_INTERVAL; 01223 pcb->rtime = -1; 01224 pcb->cwnd = 1; 01225 iss = tcp_next_iss(); 01226 pcb->snd_wl2 = iss; 01227 pcb->snd_nxt = iss; 01228 pcb->lastack = iss; 01229 pcb->snd_lbb = iss; 01230 pcb->tmr = tcp_ticks; 01231 01232 pcb->polltmr = 0; 01233 01234 #if LWIP_CALLBACK_API 01235 pcb->recv = tcp_recv_null; 01236 #endif /* LWIP_CALLBACK_API */ 01237 01238 /* Init KEEPALIVE timer */ 01239 pcb->keep_idle = TCP_KEEPIDLE_DEFAULT; 01240 01241 #if LWIP_TCP_KEEPALIVE 01242 pcb->keep_intvl = TCP_KEEPINTVL_DEFAULT; 01243 pcb->keep_cnt = TCP_KEEPCNT_DEFAULT; 01244 #endif /* LWIP_TCP_KEEPALIVE */ 01245 01246 pcb->keep_cnt_sent = 0; 01247 } 01248 return pcb; 01249 } 01250 01251 /** 01252 * Creates a new TCP protocol control block but doesn't place it on 01253 * any of the TCP PCB lists. 01254 * The pcb is not put on any list until binding using tcp_bind(). 01255 * 01256 * @internal: Maybe there should be a idle TCP PCB list where these 01257 * PCBs are put on. Port reservation using tcp_bind() is implemented but 01258 * allocated pcbs that are not bound can't be killed automatically if wanting 01259 * to allocate a pcb with higher prio (@see tcp_kill_prio()) 01260 * 01261 * @return a new tcp_pcb that initially is in state CLOSED 01262 */ 01263 struct tcp_pcb * 01264 tcp_new(void) 01265 { 01266 return tcp_alloc(TCP_PRIO_NORMAL); 01267 } 01268 01269 /** 01270 * Used to specify the argument that should be passed callback 01271 * functions. 01272 * 01273 * @param pcb tcp_pcb to set the callback argument 01274 * @param arg void pointer argument to pass to callback functions 01275 */ 01276 void 01277 tcp_arg(struct tcp_pcb *pcb, void *arg) 01278 { 01279 pcb->callback_arg = arg; 01280 } 01281 #if LWIP_CALLBACK_API 01282 01283 /** 01284 * Used to specify the function that should be called when a TCP 01285 * connection receives data. 01286 * 01287 * @param pcb tcp_pcb to set the recv callback 01288 * @param recv callback function to call for this pcb when data is received 01289 */ 01290 void 01291 tcp_recv(struct tcp_pcb *pcb, tcp_recv_fn recv) 01292 { 01293 pcb->recv = recv; 01294 } 01295 01296 /** 01297 * Used to specify the function that should be called when TCP data 01298 * has been successfully delivered to the remote host. 01299 * 01300 * @param pcb tcp_pcb to set the sent callback 01301 * @param sent callback function to call for this pcb when data is successfully sent 01302 */ 01303 void 01304 tcp_sent(struct tcp_pcb *pcb, tcp_sent_fn sent) 01305 { 01306 pcb->sent = sent; 01307 } 01308 01309 /** 01310 * Used to specify the function that should be called when a fatal error 01311 * has occured on the connection. 01312 * 01313 * @param pcb tcp_pcb to set the err callback 01314 * @param err callback function to call for this pcb when a fatal error 01315 * has occured on the connection 01316 */ 01317 void 01318 tcp_err(struct tcp_pcb *pcb, tcp_err_fn err) 01319 { 01320 pcb->errf = err; 01321 } 01322 01323 /** 01324 * Used for specifying the function that should be called when a 01325 * LISTENing connection has been connected to another host. 01326 * 01327 * @param pcb tcp_pcb to set the accept callback 01328 * @param accept callback function to call for this pcb when LISTENing 01329 * connection has been connected to another host 01330 */ 01331 void 01332 tcp_accept(struct tcp_pcb *pcb, tcp_accept_fn accept) 01333 { 01334 pcb->accept = accept; 01335 } 01336 #endif /* LWIP_CALLBACK_API */ 01337 01338 01339 /** 01340 * Used to specify the function that should be called periodically 01341 * from TCP. The interval is specified in terms of the TCP coarse 01342 * timer interval, which is called twice a second. 01343 * 01344 */ 01345 void 01346 tcp_poll(struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval) 01347 { 01348 #if LWIP_CALLBACK_API 01349 pcb->poll = poll; 01350 #else /* LWIP_CALLBACK_API */ 01351 LWIP_UNUSED_ARG(poll); 01352 #endif /* LWIP_CALLBACK_API */ 01353 pcb->pollinterval = interval; 01354 } 01355 01356 /** 01357 * Purges a TCP PCB. Removes any buffered data and frees the buffer memory 01358 * (pcb->ooseq, pcb->unsent and pcb->unacked are freed). 01359 * 01360 * @param pcb tcp_pcb to purge. The pcb itself is not deallocated! 01361 */ 01362 void 01363 tcp_pcb_purge(struct tcp_pcb *pcb) 01364 { 01365 if (pcb->state != CLOSED && 01366 pcb->state != TIME_WAIT && 01367 pcb->state != LISTEN) { 01368 01369 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge\n")); 01370 01371 #if TCP_LISTEN_BACKLOG 01372 if (pcb->state == SYN_RCVD) { 01373 /* Need to find the corresponding listen_pcb and decrease its accepts_pending */ 01374 struct tcp_pcb_listen *lpcb; 01375 LWIP_ASSERT("tcp_pcb_purge: pcb->state == SYN_RCVD but tcp_listen_pcbs is NULL", 01376 tcp_listen_pcbs.listen_pcbs != NULL); 01377 for (lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) { 01378 if ((lpcb->local_port == pcb->local_port) && 01379 (ip_addr_isany(&lpcb->local_ip) || 01380 ip_addr_cmp(&pcb->local_ip, &lpcb->local_ip))) { 01381 /* port and address of the listen pcb match the timed-out pcb */ 01382 LWIP_ASSERT("tcp_pcb_purge: listen pcb does not have accepts pending", 01383 lpcb->accepts_pending > 0); 01384 lpcb->accepts_pending--; 01385 break; 01386 } 01387 } 01388 } 01389 #endif /* TCP_LISTEN_BACKLOG */ 01390 01391 01392 if (pcb->refused_data != NULL) { 01393 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->refused_data\n")); 01394 pbuf_free(pcb->refused_data); 01395 pcb->refused_data = NULL; 01396 } 01397 if (pcb->unsent != NULL) { 01398 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: not all data sent\n")); 01399 } 01400 if (pcb->unacked != NULL) { 01401 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->unacked\n")); 01402 } 01403 #if TCP_QUEUE_OOSEQ 01404 if (pcb->ooseq != NULL) { 01405 LWIP_DEBUGF(TCP_DEBUG, ("tcp_pcb_purge: data left on ->ooseq\n")); 01406 } 01407 tcp_segs_free(pcb->ooseq); 01408 pcb->ooseq = NULL; 01409 #endif /* TCP_QUEUE_OOSEQ */ 01410 01411 /* Stop the retransmission timer as it will expect data on unacked 01412 queue if it fires */ 01413 pcb->rtime = -1; 01414 01415 tcp_segs_free(pcb->unsent); 01416 tcp_segs_free(pcb->unacked); 01417 pcb->unacked = pcb->unsent = NULL; 01418 #if TCP_OVERSIZE 01419 pcb->unsent_oversize = 0; 01420 #endif /* TCP_OVERSIZE */ 01421 } 01422 } 01423 01424 /** 01425 * Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first. 01426 * 01427 * @param pcblist PCB list to purge. 01428 * @param pcb tcp_pcb to purge. The pcb itself is NOT deallocated! 01429 */ 01430 void 01431 tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb) 01432 { 01433 TCP_RMV(pcblist, pcb); 01434 01435 tcp_pcb_purge(pcb); 01436 01437 /* if there is an outstanding delayed ACKs, send it */ 01438 if (pcb->state != TIME_WAIT && 01439 pcb->state != LISTEN && 01440 pcb->flags & TF_ACK_DELAY) { 01441 pcb->flags |= TF_ACK_NOW; 01442 tcp_output(pcb); 01443 } 01444 01445 if (pcb->state != LISTEN) { 01446 LWIP_ASSERT("unsent segments leaking", pcb->unsent == NULL); 01447 LWIP_ASSERT("unacked segments leaking", pcb->unacked == NULL); 01448 #if TCP_QUEUE_OOSEQ 01449 LWIP_ASSERT("ooseq segments leaking", pcb->ooseq == NULL); 01450 #endif /* TCP_QUEUE_OOSEQ */ 01451 } 01452 01453 pcb->state = CLOSED; 01454 01455 LWIP_ASSERT("tcp_pcb_remove: tcp_pcbs_sane()", tcp_pcbs_sane()); 01456 } 01457 01458 /** 01459 * Calculates a new initial sequence number for new connections. 01460 * 01461 * @return u32_t pseudo random sequence number 01462 */ 01463 u32_t 01464 tcp_next_iss(void) 01465 { 01466 static u32_t iss = 6510; 01467 01468 iss += tcp_ticks; /* XXX */ 01469 return iss; 01470 } 01471 01472 #if TCP_CALCULATE_EFF_SEND_MSS 01473 /** 01474 * Calcluates the effective send mss that can be used for a specific IP address 01475 * by using ip_route to determin the netif used to send to the address and 01476 * calculating the minimum of TCP_MSS and that netif's mtu (if set). 01477 */ 01478 u16_t 01479 tcp_eff_send_mss(u16_t sendmss, ip_addr_t *addr) 01480 { 01481 u16_t mss_s; 01482 struct netif *outif; 01483 01484 outif = ip_route(addr); 01485 if ((outif != NULL) && (outif->mtu != 0)) { 01486 mss_s = outif->mtu - IP_HLEN - TCP_HLEN; 01487 /* RFC 1122, chap 4.2.2.6: 01488 * Eff.snd.MSS = min(SendMSS+20, MMS_S) - TCPhdrsize - IPoptionsize 01489 * We correct for TCP options in tcp_write(), and don't support IP options. 01490 */ 01491 sendmss = LWIP_MIN(sendmss, mss_s); 01492 } 01493 return sendmss; 01494 } 01495 #endif /* TCP_CALCULATE_EFF_SEND_MSS */ 01496 01497 const char* 01498 tcp_debug_state_str(enum tcp_state s) 01499 { 01500 return tcp_state_str[s]; 01501 } 01502 01503 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG 01504 /** 01505 * Print a tcp header for debugging purposes. 01506 * 01507 * @param tcphdr pointer to a struct tcp_hdr 01508 */ 01509 void 01510 tcp_debug_print(struct tcp_hdr *tcphdr) 01511 { 01512 LWIP_DEBUGF(TCP_DEBUG, ("TCP header:\n")); 01513 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01514 LWIP_DEBUGF(TCP_DEBUG, ("| %5"U16_F" | %5"U16_F" | (src port, dest port)\n", 01515 ntohs(tcphdr->src), ntohs(tcphdr->dest))); 01516 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01517 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (seq no)\n", 01518 ntohl(tcphdr->seqno))); 01519 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01520 LWIP_DEBUGF(TCP_DEBUG, ("| %010"U32_F" | (ack no)\n", 01521 ntohl(tcphdr->ackno))); 01522 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01523 LWIP_DEBUGF(TCP_DEBUG, ("| %2"U16_F" | |%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"%"U16_F"| %5"U16_F" | (hdrlen, flags (", 01524 TCPH_HDRLEN(tcphdr), 01525 TCPH_FLAGS(tcphdr) >> 5 & 1, 01526 TCPH_FLAGS(tcphdr) >> 4 & 1, 01527 TCPH_FLAGS(tcphdr) >> 3 & 1, 01528 TCPH_FLAGS(tcphdr) >> 2 & 1, 01529 TCPH_FLAGS(tcphdr) >> 1 & 1, 01530 TCPH_FLAGS(tcphdr) & 1, 01531 ntohs(tcphdr->wnd))); 01532 tcp_debug_print_flags(TCPH_FLAGS(tcphdr)); 01533 LWIP_DEBUGF(TCP_DEBUG, ("), win)\n")); 01534 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01535 LWIP_DEBUGF(TCP_DEBUG, ("| 0x%04"X16_F" | %5"U16_F" | (chksum, urgp)\n", 01536 ntohs(tcphdr->chksum), ntohs(tcphdr->urgp))); 01537 LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n")); 01538 } 01539 01540 /** 01541 * Print a tcp state for debugging purposes. 01542 * 01543 * @param s enum tcp_state to print 01544 */ 01545 void 01546 tcp_debug_print_state(enum tcp_state s) 01547 { 01548 LWIP_DEBUGF(TCP_DEBUG, ("State: %s\n", tcp_state_str[s])); 01549 } 01550 01551 /** 01552 * Print tcp flags for debugging purposes. 01553 * 01554 * @param flags tcp flags, all active flags are printed 01555 */ 01556 void 01557 tcp_debug_print_flags(u8_t flags) 01558 { 01559 if (flags & TCP_FIN) { 01560 LWIP_DEBUGF(TCP_DEBUG, ("FIN ")); 01561 } 01562 if (flags & TCP_SYN) { 01563 LWIP_DEBUGF(TCP_DEBUG, ("SYN ")); 01564 } 01565 if (flags & TCP_RST) { 01566 LWIP_DEBUGF(TCP_DEBUG, ("RST ")); 01567 } 01568 if (flags & TCP_PSH) { 01569 LWIP_DEBUGF(TCP_DEBUG, ("PSH ")); 01570 } 01571 if (flags & TCP_ACK) { 01572 LWIP_DEBUGF(TCP_DEBUG, ("ACK ")); 01573 } 01574 if (flags & TCP_URG) { 01575 LWIP_DEBUGF(TCP_DEBUG, ("URG ")); 01576 } 01577 if (flags & TCP_ECE) { 01578 LWIP_DEBUGF(TCP_DEBUG, ("ECE ")); 01579 } 01580 if (flags & TCP_CWR) { 01581 LWIP_DEBUGF(TCP_DEBUG, ("CWR ")); 01582 } 01583 LWIP_DEBUGF(TCP_DEBUG, ("\n")); 01584 } 01585 01586 /** 01587 * Print all tcp_pcbs in every list for debugging purposes. 01588 */ 01589 void 01590 tcp_debug_print_pcbs(void) 01591 { 01592 struct tcp_pcb *pcb; 01593 LWIP_DEBUGF(TCP_DEBUG, ("Active PCB states:\n")); 01594 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { 01595 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ", 01596 pcb->local_port, pcb->remote_port, 01597 pcb->snd_nxt, pcb->rcv_nxt)); 01598 tcp_debug_print_state(pcb->state); 01599 } 01600 LWIP_DEBUGF(TCP_DEBUG, ("Listen PCB states:\n")); 01601 for(pcb = (struct tcp_pcb *)tcp_listen_pcbs.pcbs; pcb != NULL; pcb = pcb->next) { 01602 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ", 01603 pcb->local_port, pcb->remote_port, 01604 pcb->snd_nxt, pcb->rcv_nxt)); 01605 tcp_debug_print_state(pcb->state); 01606 } 01607 LWIP_DEBUGF(TCP_DEBUG, ("TIME-WAIT PCB states:\n")); 01608 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) { 01609 LWIP_DEBUGF(TCP_DEBUG, ("Local port %"U16_F", foreign port %"U16_F" snd_nxt %"U32_F" rcv_nxt %"U32_F" ", 01610 pcb->local_port, pcb->remote_port, 01611 pcb->snd_nxt, pcb->rcv_nxt)); 01612 tcp_debug_print_state(pcb->state); 01613 } 01614 } 01615 01616 /** 01617 * Check state consistency of the tcp_pcb lists. 01618 */ 01619 s16_t 01620 tcp_pcbs_sane(void) 01621 { 01622 struct tcp_pcb *pcb; 01623 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { 01624 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != CLOSED", pcb->state != CLOSED); 01625 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != LISTEN", pcb->state != LISTEN); 01626 LWIP_ASSERT("tcp_pcbs_sane: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT); 01627 } 01628 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) { 01629 LWIP_ASSERT("tcp_pcbs_sane: tw pcb->state == TIME-WAIT", pcb->state == TIME_WAIT); 01630 } 01631 return 1; 01632 } 01633 #endif /* TCP_DEBUG */ 01634 01635 #endif /* LWIP_TCP */
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