Pascal Nysten / lwip

Adapted to Lora Semtech + Nucleo

Dependencies:   DebugLib

Dependents:   LoRaWAN-lmic-app LoRaWAN-lmic-app LoRaWAN-test-10secs LoRaPersonalizedDeviceForEverynet ... more

Fork of lwip_ppp_ethernet by Donatien Garnier

src/core/tcp_in.c@3:a9e6ba815945, 2015-11-20 (annotated)

Committer:
pnysten
Date:
Fri Nov 20 12:30:58 2015 +0000
Revision:
3:a9e6ba815945
Parent:
0:8e01dca41002 
Adapted to Nucleo, LoRa Semtech

Who changed what in which revision?

UserRevisionLine numberNew contents of line
donatien 0:8e01dca41002 1 /**
donatien 0:8e01dca41002 2 * @file
donatien 0:8e01dca41002 3 * Transmission Control Protocol, incoming traffic
donatien 0:8e01dca41002 4 *
donatien 0:8e01dca41002 5 * The input processing functions of the TCP layer.
donatien 0:8e01dca41002 6 *
donatien 0:8e01dca41002 7 * These functions are generally called in the order (ip_input() ->)
donatien 0:8e01dca41002 8 * tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
donatien 0:8e01dca41002 9 *
donatien 0:8e01dca41002 10 */
donatien 0:8e01dca41002 11
donatien 0:8e01dca41002 12 /*
donatien 0:8e01dca41002 13 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
donatien 0:8e01dca41002 14 * All rights reserved.
donatien 0:8e01dca41002 15 *
donatien 0:8e01dca41002 16 * Redistribution and use in source and binary forms, with or without modification,
donatien 0:8e01dca41002 17 * are permitted provided that the following conditions are met:
donatien 0:8e01dca41002 18 *
donatien 0:8e01dca41002 19 * 1. Redistributions of source code must retain the above copyright notice,
donatien 0:8e01dca41002 20 * this list of conditions and the following disclaimer.
donatien 0:8e01dca41002 21 * 2. Redistributions in binary form must reproduce the above copyright notice,
donatien 0:8e01dca41002 22 * this list of conditions and the following disclaimer in the documentation
donatien 0:8e01dca41002 23 * and/or other materials provided with the distribution.
donatien 0:8e01dca41002 24 * 3. The name of the author may not be used to endorse or promote products
donatien 0:8e01dca41002 25 * derived from this software without specific prior written permission.
donatien 0:8e01dca41002 26 *
donatien 0:8e01dca41002 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
donatien 0:8e01dca41002 28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
donatien 0:8e01dca41002 29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
donatien 0:8e01dca41002 30 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
donatien 0:8e01dca41002 31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
donatien 0:8e01dca41002 32 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
donatien 0:8e01dca41002 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
donatien 0:8e01dca41002 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
donatien 0:8e01dca41002 35 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
donatien 0:8e01dca41002 36 * OF SUCH DAMAGE.
donatien 0:8e01dca41002 37 *
donatien 0:8e01dca41002 38 * This file is part of the lwIP TCP/IP stack.
donatien 0:8e01dca41002 39 *
donatien 0:8e01dca41002 40 * Author: Adam Dunkels <adam@sics.se>
donatien 0:8e01dca41002 41 *
donatien 0:8e01dca41002 42 */
donatien 0:8e01dca41002 43
donatien 0:8e01dca41002 44 #include "lwip/opt.h"
donatien 0:8e01dca41002 45
donatien 0:8e01dca41002 46 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
donatien 0:8e01dca41002 47
donatien 0:8e01dca41002 48 #include "lwip/tcp_impl.h"
donatien 0:8e01dca41002 49 #include "lwip/def.h"
donatien 0:8e01dca41002 50 #include "lwip/ip_addr.h"
donatien 0:8e01dca41002 51 #include "lwip/netif.h"
donatien 0:8e01dca41002 52 #include "lwip/mem.h"
donatien 0:8e01dca41002 53 #include "lwip/memp.h"
donatien 0:8e01dca41002 54 #include "lwip/inet_chksum.h"
donatien 0:8e01dca41002 55 #include "lwip/stats.h"
donatien 0:8e01dca41002 56 #include "lwip/snmp.h"
donatien 0:8e01dca41002 57 #include "arch/perf.h"
donatien 0:8e01dca41002 58
donatien 0:8e01dca41002 59 /* These variables are global to all functions involved in the input
donatien 0:8e01dca41002 60 processing of TCP segments. They are set by the tcp_input()
donatien 0:8e01dca41002 61 function. */
donatien 0:8e01dca41002 62 static struct tcp_seg inseg;
donatien 0:8e01dca41002 63 static struct tcp_hdr *tcphdr;
donatien 0:8e01dca41002 64 static struct ip_hdr *iphdr;
donatien 0:8e01dca41002 65 static u32_t seqno, ackno;
donatien 0:8e01dca41002 66 static u8_t flags;
donatien 0:8e01dca41002 67 static u16_t tcplen;
donatien 0:8e01dca41002 68
donatien 0:8e01dca41002 69 static u8_t recv_flags;
donatien 0:8e01dca41002 70 static struct pbuf *recv_data;
donatien 0:8e01dca41002 71
donatien 0:8e01dca41002 72 struct tcp_pcb *tcp_input_pcb;
donatien 0:8e01dca41002 73
donatien 0:8e01dca41002 74 /* Forward declarations. */
donatien 0:8e01dca41002 75 static err_t tcp_process(struct tcp_pcb *pcb);
donatien 0:8e01dca41002 76 static void tcp_receive(struct tcp_pcb *pcb);
donatien 0:8e01dca41002 77 static void tcp_parseopt(struct tcp_pcb *pcb);
donatien 0:8e01dca41002 78
donatien 0:8e01dca41002 79 static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
donatien 0:8e01dca41002 80 static err_t tcp_timewait_input(struct tcp_pcb *pcb);
donatien 0:8e01dca41002 81
donatien 0:8e01dca41002 82 /**
donatien 0:8e01dca41002 83 * The initial input processing of TCP. It verifies the TCP header, demultiplexes
donatien 0:8e01dca41002 84 * the segment between the PCBs and passes it on to tcp_process(), which implements
donatien 0:8e01dca41002 85 * the TCP finite state machine. This function is called by the IP layer (in
donatien 0:8e01dca41002 86 * ip_input()).
donatien 0:8e01dca41002 87 *
donatien 0:8e01dca41002 88 * @param p received TCP segment to process (p->payload pointing to the IP header)
donatien 0:8e01dca41002 89 * @param inp network interface on which this segment was received
donatien 0:8e01dca41002 90 */
donatien 0:8e01dca41002 91 void
donatien 0:8e01dca41002 92 tcp_input(struct pbuf *p, struct netif *inp)
donatien 0:8e01dca41002 93 {
donatien 0:8e01dca41002 94 struct tcp_pcb *pcb, *prev;
donatien 0:8e01dca41002 95 struct tcp_pcb_listen *lpcb;
donatien 0:8e01dca41002 96 #if SO_REUSE
donatien 0:8e01dca41002 97 struct tcp_pcb *lpcb_prev = NULL;
donatien 0:8e01dca41002 98 struct tcp_pcb_listen *lpcb_any = NULL;
donatien 0:8e01dca41002 99 #endif /* SO_REUSE */
donatien 0:8e01dca41002 100 u8_t hdrlen;
donatien 0:8e01dca41002 101 err_t err;
donatien 0:8e01dca41002 102
donatien 0:8e01dca41002 103 PERF_START;
donatien 0:8e01dca41002 104
donatien 0:8e01dca41002 105 TCP_STATS_INC(tcp.recv);
donatien 0:8e01dca41002 106 snmp_inc_tcpinsegs();
donatien 0:8e01dca41002 107
donatien 0:8e01dca41002 108 iphdr = (struct ip_hdr *)p->payload;
donatien 0:8e01dca41002 109 tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
donatien 0:8e01dca41002 110
donatien 0:8e01dca41002 111 #if TCP_INPUT_DEBUG
donatien 0:8e01dca41002 112 tcp_debug_print(tcphdr);
donatien 0:8e01dca41002 113 #endif
donatien 0:8e01dca41002 114
donatien 0:8e01dca41002 115 /* remove header from payload */
donatien 0:8e01dca41002 116 if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) {
donatien 0:8e01dca41002 117 /* drop short packets */
donatien 0:8e01dca41002 118 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
donatien 0:8e01dca41002 119 TCP_STATS_INC(tcp.lenerr);
donatien 0:8e01dca41002 120 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 121 snmp_inc_tcpinerrs();
donatien 0:8e01dca41002 122 pbuf_free(p);
donatien 0:8e01dca41002 123 return;
donatien 0:8e01dca41002 124 }
donatien 0:8e01dca41002 125
donatien 0:8e01dca41002 126 /* Don't even process incoming broadcasts/multicasts. */
donatien 0:8e01dca41002 127 if (ip_addr_isbroadcast(&current_iphdr_dest, inp) ||
donatien 0:8e01dca41002 128 ip_addr_ismulticast(&current_iphdr_dest)) {
donatien 0:8e01dca41002 129 TCP_STATS_INC(tcp.proterr);
donatien 0:8e01dca41002 130 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 131 snmp_inc_tcpinerrs();
donatien 0:8e01dca41002 132 pbuf_free(p);
donatien 0:8e01dca41002 133 return;
donatien 0:8e01dca41002 134 }
donatien 0:8e01dca41002 135
donatien 0:8e01dca41002 136 #if CHECKSUM_CHECK_TCP
donatien 0:8e01dca41002 137 /* Verify TCP checksum. */
donatien 0:8e01dca41002 138 if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
donatien 0:8e01dca41002 139 IP_PROTO_TCP, p->tot_len) != 0) {
donatien 0:8e01dca41002 140 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
donatien 0:8e01dca41002 141 inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
donatien 0:8e01dca41002 142 IP_PROTO_TCP, p->tot_len)));
donatien 0:8e01dca41002 143 #if TCP_DEBUG
donatien 0:8e01dca41002 144 tcp_debug_print(tcphdr);
donatien 0:8e01dca41002 145 #endif /* TCP_DEBUG */
donatien 0:8e01dca41002 146 TCP_STATS_INC(tcp.chkerr);
donatien 0:8e01dca41002 147 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 148 snmp_inc_tcpinerrs();
donatien 0:8e01dca41002 149 pbuf_free(p);
donatien 0:8e01dca41002 150 return;
donatien 0:8e01dca41002 151 }
donatien 0:8e01dca41002 152 #endif
donatien 0:8e01dca41002 153
donatien 0:8e01dca41002 154 /* Move the payload pointer in the pbuf so that it points to the
donatien 0:8e01dca41002 155 TCP data instead of the TCP header. */
donatien 0:8e01dca41002 156 hdrlen = TCPH_HDRLEN(tcphdr);
donatien 0:8e01dca41002 157 if(pbuf_header(p, -(hdrlen * 4))){
donatien 0:8e01dca41002 158 /* drop short packets */
donatien 0:8e01dca41002 159 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
donatien 0:8e01dca41002 160 TCP_STATS_INC(tcp.lenerr);
donatien 0:8e01dca41002 161 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 162 snmp_inc_tcpinerrs();
donatien 0:8e01dca41002 163 pbuf_free(p);
donatien 0:8e01dca41002 164 return;
donatien 0:8e01dca41002 165 }
donatien 0:8e01dca41002 166
donatien 0:8e01dca41002 167 /* Convert fields in TCP header to host byte order. */
donatien 0:8e01dca41002 168 tcphdr->src = ntohs(tcphdr->src);
donatien 0:8e01dca41002 169 tcphdr->dest = ntohs(tcphdr->dest);
donatien 0:8e01dca41002 170 seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
donatien 0:8e01dca41002 171 ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
donatien 0:8e01dca41002 172 tcphdr->wnd = ntohs(tcphdr->wnd);
donatien 0:8e01dca41002 173
donatien 0:8e01dca41002 174 flags = TCPH_FLAGS(tcphdr);
donatien 0:8e01dca41002 175 tcplen = p->tot_len + ((flags & (TCP_FIN | TCP_SYN)) ? 1 : 0);
donatien 0:8e01dca41002 176
donatien 0:8e01dca41002 177 /* Demultiplex an incoming segment. First, we check if it is destined
donatien 0:8e01dca41002 178 for an active connection. */
donatien 0:8e01dca41002 179 prev = NULL;
donatien 0:8e01dca41002 180
donatien 0:8e01dca41002 181
donatien 0:8e01dca41002 182 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
donatien 0:8e01dca41002 183 LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
donatien 0:8e01dca41002 184 LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
donatien 0:8e01dca41002 185 LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
donatien 0:8e01dca41002 186 if (pcb->remote_port == tcphdr->src &&
donatien 0:8e01dca41002 187 pcb->local_port == tcphdr->dest &&
donatien 0:8e01dca41002 188 ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
donatien 0:8e01dca41002 189 ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
donatien 0:8e01dca41002 190
donatien 0:8e01dca41002 191 /* Move this PCB to the front of the list so that subsequent
donatien 0:8e01dca41002 192 lookups will be faster (we exploit locality in TCP segment
donatien 0:8e01dca41002 193 arrivals). */
donatien 0:8e01dca41002 194 LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
donatien 0:8e01dca41002 195 if (prev != NULL) {
donatien 0:8e01dca41002 196 prev->next = pcb->next;
donatien 0:8e01dca41002 197 pcb->next = tcp_active_pcbs;
donatien 0:8e01dca41002 198 tcp_active_pcbs = pcb;
donatien 0:8e01dca41002 199 }
donatien 0:8e01dca41002 200 LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
donatien 0:8e01dca41002 201 break;
donatien 0:8e01dca41002 202 }
donatien 0:8e01dca41002 203 prev = pcb;
donatien 0:8e01dca41002 204 }
donatien 0:8e01dca41002 205
donatien 0:8e01dca41002 206 if (pcb == NULL) {
donatien 0:8e01dca41002 207 /* If it did not go to an active connection, we check the connections
donatien 0:8e01dca41002 208 in the TIME-WAIT state. */
donatien 0:8e01dca41002 209 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
donatien 0:8e01dca41002 210 LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
donatien 0:8e01dca41002 211 if (pcb->remote_port == tcphdr->src &&
donatien 0:8e01dca41002 212 pcb->local_port == tcphdr->dest &&
donatien 0:8e01dca41002 213 ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
donatien 0:8e01dca41002 214 ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
donatien 0:8e01dca41002 215 /* We don't really care enough to move this PCB to the front
donatien 0:8e01dca41002 216 of the list since we are not very likely to receive that
donatien 0:8e01dca41002 217 many segments for connections in TIME-WAIT. */
donatien 0:8e01dca41002 218 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
donatien 0:8e01dca41002 219 tcp_timewait_input(pcb);
donatien 0:8e01dca41002 220 pbuf_free(p);
donatien 0:8e01dca41002 221 return;
donatien 0:8e01dca41002 222 }
donatien 0:8e01dca41002 223 }
donatien 0:8e01dca41002 224
donatien 0:8e01dca41002 225 /* Finally, if we still did not get a match, we check all PCBs that
donatien 0:8e01dca41002 226 are LISTENing for incoming connections. */
donatien 0:8e01dca41002 227 prev = NULL;
donatien 0:8e01dca41002 228 for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
donatien 0:8e01dca41002 229 if (lpcb->local_port == tcphdr->dest) {
donatien 0:8e01dca41002 230 #if SO_REUSE
donatien 0:8e01dca41002 231 if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
donatien 0:8e01dca41002 232 /* found an exact match */
donatien 0:8e01dca41002 233 break;
donatien 0:8e01dca41002 234 } else if(ip_addr_isany(&(lpcb->local_ip))) {
donatien 0:8e01dca41002 235 /* found an ANY-match */
donatien 0:8e01dca41002 236 lpcb_any = lpcb;
donatien 0:8e01dca41002 237 lpcb_prev = prev;
donatien 0:8e01dca41002 238 }
donatien 0:8e01dca41002 239 #else /* SO_REUSE */
donatien 0:8e01dca41002 240 if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) ||
donatien 0:8e01dca41002 241 ip_addr_isany(&(lpcb->local_ip))) {
donatien 0:8e01dca41002 242 /* found a match */
donatien 0:8e01dca41002 243 break;
donatien 0:8e01dca41002 244 }
donatien 0:8e01dca41002 245 #endif /* SO_REUSE */
donatien 0:8e01dca41002 246 }
donatien 0:8e01dca41002 247 prev = (struct tcp_pcb *)lpcb;
donatien 0:8e01dca41002 248 }
donatien 0:8e01dca41002 249 #if SO_REUSE
donatien 0:8e01dca41002 250 /* first try specific local IP */
donatien 0:8e01dca41002 251 if (lpcb == NULL) {
donatien 0:8e01dca41002 252 /* only pass to ANY if no specific local IP has been found */
donatien 0:8e01dca41002 253 lpcb = lpcb_any;
donatien 0:8e01dca41002 254 prev = lpcb_prev;
donatien 0:8e01dca41002 255 }
donatien 0:8e01dca41002 256 #endif /* SO_REUSE */
donatien 0:8e01dca41002 257 if (lpcb != NULL) {
donatien 0:8e01dca41002 258 /* Move this PCB to the front of the list so that subsequent
donatien 0:8e01dca41002 259 lookups will be faster (we exploit locality in TCP segment
donatien 0:8e01dca41002 260 arrivals). */
donatien 0:8e01dca41002 261 if (prev != NULL) {
donatien 0:8e01dca41002 262 ((struct tcp_pcb_listen *)prev)->next = lpcb->next;
donatien 0:8e01dca41002 263 /* our successor is the remainder of the listening list */
donatien 0:8e01dca41002 264 lpcb->next = tcp_listen_pcbs.listen_pcbs;
donatien 0:8e01dca41002 265 /* put this listening pcb at the head of the listening list */
donatien 0:8e01dca41002 266 tcp_listen_pcbs.listen_pcbs = lpcb;
donatien 0:8e01dca41002 267 }
donatien 0:8e01dca41002 268
donatien 0:8e01dca41002 269 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
donatien 0:8e01dca41002 270 tcp_listen_input(lpcb);
donatien 0:8e01dca41002 271 pbuf_free(p);
donatien 0:8e01dca41002 272 return;
donatien 0:8e01dca41002 273 }
donatien 0:8e01dca41002 274 }
donatien 0:8e01dca41002 275
donatien 0:8e01dca41002 276 #if TCP_INPUT_DEBUG
donatien 0:8e01dca41002 277 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
donatien 0:8e01dca41002 278 tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
donatien 0:8e01dca41002 279 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
donatien 0:8e01dca41002 280 #endif /* TCP_INPUT_DEBUG */
donatien 0:8e01dca41002 281
donatien 0:8e01dca41002 282
donatien 0:8e01dca41002 283 if (pcb != NULL) {
donatien 0:8e01dca41002 284 /* The incoming segment belongs to a connection. */
donatien 0:8e01dca41002 285 #if TCP_INPUT_DEBUG
donatien 0:8e01dca41002 286 #if TCP_DEBUG
donatien 0:8e01dca41002 287 tcp_debug_print_state(pcb->state);
donatien 0:8e01dca41002 288 #endif /* TCP_DEBUG */
donatien 0:8e01dca41002 289 #endif /* TCP_INPUT_DEBUG */
donatien 0:8e01dca41002 290
donatien 0:8e01dca41002 291 /* Set up a tcp_seg structure. */
donatien 0:8e01dca41002 292 inseg.next = NULL;
donatien 0:8e01dca41002 293 inseg.len = p->tot_len;
donatien 0:8e01dca41002 294 inseg.p = p;
donatien 0:8e01dca41002 295 inseg.tcphdr = tcphdr;
donatien 0:8e01dca41002 296
donatien 0:8e01dca41002 297 recv_data = NULL;
donatien 0:8e01dca41002 298 recv_flags = 0;
donatien 0:8e01dca41002 299
donatien 0:8e01dca41002 300 /* If there is data which was previously "refused" by upper layer */
donatien 0:8e01dca41002 301 if (pcb->refused_data != NULL) {
donatien 0:8e01dca41002 302 /* Notify again application with data previously received. */
donatien 0:8e01dca41002 303 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
donatien 0:8e01dca41002 304 TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
donatien 0:8e01dca41002 305 if (err == ERR_OK) {
donatien 0:8e01dca41002 306 pcb->refused_data = NULL;
donatien 0:8e01dca41002 307 } else if ((err == ERR_ABRT) || (tcplen > 0)) {
donatien 0:8e01dca41002 308 /* if err == ERR_ABRT, 'pcb' is already deallocated */
donatien 0:8e01dca41002 309 /* Drop incoming packets because pcb is "full" (only if the incoming
donatien 0:8e01dca41002 310 segment contains data). */
donatien 0:8e01dca41002 311 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
donatien 0:8e01dca41002 312 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 313 snmp_inc_tcpinerrs();
donatien 0:8e01dca41002 314 pbuf_free(p);
donatien 0:8e01dca41002 315 return;
donatien 0:8e01dca41002 316 }
donatien 0:8e01dca41002 317 }
donatien 0:8e01dca41002 318 tcp_input_pcb = pcb;
donatien 0:8e01dca41002 319 err = tcp_process(pcb);
donatien 0:8e01dca41002 320 /* A return value of ERR_ABRT means that tcp_abort() was called
donatien 0:8e01dca41002 321 and that the pcb has been freed. If so, we don't do anything. */
donatien 0:8e01dca41002 322 if (err != ERR_ABRT) {
donatien 0:8e01dca41002 323 if (recv_flags & TF_RESET) {
donatien 0:8e01dca41002 324 /* TF_RESET means that the connection was reset by the other
donatien 0:8e01dca41002 325 end. We then call the error callback to inform the
donatien 0:8e01dca41002 326 application that the connection is dead before we
donatien 0:8e01dca41002 327 deallocate the PCB. */
donatien 0:8e01dca41002 328 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
donatien 0:8e01dca41002 329 tcp_pcb_remove(&tcp_active_pcbs, pcb);
donatien 0:8e01dca41002 330 memp_free(MEMP_TCP_PCB, pcb);
donatien 0:8e01dca41002 331 } else if (recv_flags & TF_CLOSED) {
donatien 0:8e01dca41002 332 /* The connection has been closed and we will deallocate the
donatien 0:8e01dca41002 333 PCB. */
donatien 0:8e01dca41002 334 tcp_pcb_remove(&tcp_active_pcbs, pcb);
donatien 0:8e01dca41002 335 memp_free(MEMP_TCP_PCB, pcb);
donatien 0:8e01dca41002 336 } else {
donatien 0:8e01dca41002 337 err = ERR_OK;
donatien 0:8e01dca41002 338 /* If the application has registered a "sent" function to be
donatien 0:8e01dca41002 339 called when new send buffer space is available, we call it
donatien 0:8e01dca41002 340 now. */
donatien 0:8e01dca41002 341 if (pcb->acked > 0) {
donatien 0:8e01dca41002 342 TCP_EVENT_SENT(pcb, pcb->acked, err);
donatien 0:8e01dca41002 343 if (err == ERR_ABRT) {
donatien 0:8e01dca41002 344 goto aborted;
donatien 0:8e01dca41002 345 }
donatien 0:8e01dca41002 346 }
donatien 0:8e01dca41002 347
donatien 0:8e01dca41002 348 if (recv_data != NULL) {
donatien 0:8e01dca41002 349 LWIP_ASSERT("pcb->refused_data == NULL", pcb->refused_data == NULL);
donatien 0:8e01dca41002 350 if (pcb->flags & TF_RXCLOSED) {
donatien 0:8e01dca41002 351 /* received data although already closed -> abort (send RST) to
donatien 0:8e01dca41002 352 notify the remote host that not all data has been processed */
donatien 0:8e01dca41002 353 pbuf_free(recv_data);
donatien 0:8e01dca41002 354 tcp_abort(pcb);
donatien 0:8e01dca41002 355 goto aborted;
donatien 0:8e01dca41002 356 }
donatien 0:8e01dca41002 357 if (flags & TCP_PSH) {
donatien 0:8e01dca41002 358 recv_data->flags |= PBUF_FLAG_PUSH;
donatien 0:8e01dca41002 359 }
donatien 0:8e01dca41002 360
donatien 0:8e01dca41002 361 /* Notify application that data has been received. */
donatien 0:8e01dca41002 362 TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
donatien 0:8e01dca41002 363 if (err == ERR_ABRT) {
donatien 0:8e01dca41002 364 goto aborted;
donatien 0:8e01dca41002 365 }
donatien 0:8e01dca41002 366
donatien 0:8e01dca41002 367 /* If the upper layer can't receive this data, store it */
donatien 0:8e01dca41002 368 if (err != ERR_OK) {
donatien 0:8e01dca41002 369 pcb->refused_data = recv_data;
donatien 0:8e01dca41002 370 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
donatien 0:8e01dca41002 371 }
donatien 0:8e01dca41002 372 }
donatien 0:8e01dca41002 373
donatien 0:8e01dca41002 374 /* If a FIN segment was received, we call the callback
donatien 0:8e01dca41002 375 function with a NULL buffer to indicate EOF. */
donatien 0:8e01dca41002 376 if (recv_flags & TF_GOT_FIN) {
donatien 0:8e01dca41002 377 /* correct rcv_wnd as the application won't call tcp_recved()
donatien 0:8e01dca41002 378 for the FIN's seqno */
donatien 0:8e01dca41002 379 if (pcb->rcv_wnd != TCP_WND) {
donatien 0:8e01dca41002 380 pcb->rcv_wnd++;
donatien 0:8e01dca41002 381 }
donatien 0:8e01dca41002 382 TCP_EVENT_CLOSED(pcb, err);
donatien 0:8e01dca41002 383 if (err == ERR_ABRT) {
donatien 0:8e01dca41002 384 goto aborted;
donatien 0:8e01dca41002 385 }
donatien 0:8e01dca41002 386 }
donatien 0:8e01dca41002 387
donatien 0:8e01dca41002 388 tcp_input_pcb = NULL;
donatien 0:8e01dca41002 389 /* Try to send something out. */
donatien 0:8e01dca41002 390 tcp_output(pcb);
donatien 0:8e01dca41002 391 #if TCP_INPUT_DEBUG
donatien 0:8e01dca41002 392 #if TCP_DEBUG
donatien 0:8e01dca41002 393 tcp_debug_print_state(pcb->state);
donatien 0:8e01dca41002 394 #endif /* TCP_DEBUG */
donatien 0:8e01dca41002 395 #endif /* TCP_INPUT_DEBUG */
donatien 0:8e01dca41002 396 }
donatien 0:8e01dca41002 397 }
donatien 0:8e01dca41002 398 /* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
donatien 0:8e01dca41002 399 Below this line, 'pcb' may not be dereferenced! */
donatien 0:8e01dca41002 400 aborted:
donatien 0:8e01dca41002 401 tcp_input_pcb = NULL;
donatien 0:8e01dca41002 402 recv_data = NULL;
donatien 0:8e01dca41002 403
donatien 0:8e01dca41002 404 /* give up our reference to inseg.p */
donatien 0:8e01dca41002 405 if (inseg.p != NULL)
donatien 0:8e01dca41002 406 {
donatien 0:8e01dca41002 407 pbuf_free(inseg.p);
donatien 0:8e01dca41002 408 inseg.p = NULL;
donatien 0:8e01dca41002 409 }
donatien 0:8e01dca41002 410 } else {
donatien 0:8e01dca41002 411
donatien 0:8e01dca41002 412 /* If no matching PCB was found, send a TCP RST (reset) to the
donatien 0:8e01dca41002 413 sender. */
donatien 0:8e01dca41002 414 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
donatien 0:8e01dca41002 415 if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
donatien 0:8e01dca41002 416 TCP_STATS_INC(tcp.proterr);
donatien 0:8e01dca41002 417 TCP_STATS_INC(tcp.drop);
donatien 0:8e01dca41002 418 tcp_rst(ackno, seqno + tcplen,
donatien 0:8e01dca41002 419 ip_current_dest_addr(), ip_current_src_addr(),
donatien 0:8e01dca41002 420 tcphdr->dest, tcphdr->src);
donatien 0:8e01dca41002 421 }
donatien 0:8e01dca41002 422 pbuf_free(p);
donatien 0:8e01dca41002 423 }
donatien 0:8e01dca41002 424
donatien 0:8e01dca41002 425 LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
donatien 0:8e01dca41002 426 PERF_STOP("tcp_input");
donatien 0:8e01dca41002 427 }
donatien 0:8e01dca41002 428
donatien 0:8e01dca41002 429 /**
donatien 0:8e01dca41002 430 * Called by tcp_input() when a segment arrives for a listening
donatien 0:8e01dca41002 431 * connection (from tcp_input()).
donatien 0:8e01dca41002 432 *
donatien 0:8e01dca41002 433 * @param pcb the tcp_pcb_listen for which a segment arrived
donatien 0:8e01dca41002 434 * @return ERR_OK if the segment was processed
donatien 0:8e01dca41002 435 * another err_t on error
donatien 0:8e01dca41002 436 *
donatien 0:8e01dca41002 437 * @note the return value is not (yet?) used in tcp_input()
donatien 0:8e01dca41002 438 * @note the segment which arrived is saved in global variables, therefore only the pcb
donatien 0:8e01dca41002 439 * involved is passed as a parameter to this function
donatien 0:8e01dca41002 440 */
donatien 0:8e01dca41002 441 static err_t
donatien 0:8e01dca41002 442 tcp_listen_input(struct tcp_pcb_listen *pcb)
donatien 0:8e01dca41002 443 {
donatien 0:8e01dca41002 444 struct tcp_pcb *npcb;
donatien 0:8e01dca41002 445 err_t rc;
donatien 0:8e01dca41002 446
donatien 0:8e01dca41002 447 /* In the LISTEN state, we check for incoming SYN segments,
donatien 0:8e01dca41002 448 creates a new PCB, and responds with a SYN|ACK. */
donatien 0:8e01dca41002 449 if (flags & TCP_ACK) {
donatien 0:8e01dca41002 450 /* For incoming segments with the ACK flag set, respond with a
donatien 0:8e01dca41002 451 RST. */
donatien 0:8e01dca41002 452 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
donatien 0:8e01dca41002 453 tcp_rst(ackno + 1, seqno + tcplen,
donatien 0:8e01dca41002 454 ip_current_dest_addr(), ip_current_src_addr(),
donatien 0:8e01dca41002 455 tcphdr->dest, tcphdr->src);
donatien 0:8e01dca41002 456 } else if (flags & TCP_SYN) {
donatien 0:8e01dca41002 457 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
donatien 0:8e01dca41002 458 #if TCP_LISTEN_BACKLOG
donatien 0:8e01dca41002 459 if (pcb->accepts_pending >= pcb->backlog) {
donatien 0:8e01dca41002 460 LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
donatien 0:8e01dca41002 461 return ERR_ABRT;
donatien 0:8e01dca41002 462 }
donatien 0:8e01dca41002 463 #endif /* TCP_LISTEN_BACKLOG */
donatien 0:8e01dca41002 464 npcb = tcp_alloc(pcb->prio);
donatien 0:8e01dca41002 465 /* If a new PCB could not be created (probably due to lack of memory),
donatien 0:8e01dca41002 466 we don't do anything, but rely on the sender will retransmit the
donatien 0:8e01dca41002 467 SYN at a time when we have more memory available. */
donatien 0:8e01dca41002 468 if (npcb == NULL) {
donatien 0:8e01dca41002 469 LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
donatien 0:8e01dca41002 470 TCP_STATS_INC(tcp.memerr);
donatien 0:8e01dca41002 471 return ERR_MEM;
donatien 0:8e01dca41002 472 }
donatien 0:8e01dca41002 473 #if TCP_LISTEN_BACKLOG
donatien 0:8e01dca41002 474 pcb->accepts_pending++;
donatien 0:8e01dca41002 475 #endif /* TCP_LISTEN_BACKLOG */
donatien 0:8e01dca41002 476 /* Set up the new PCB. */
donatien 0:8e01dca41002 477 ip_addr_copy(npcb->local_ip, current_iphdr_dest);
donatien 0:8e01dca41002 478 npcb->local_port = pcb->local_port;
donatien 0:8e01dca41002 479 ip_addr_copy(npcb->remote_ip, current_iphdr_src);
donatien 0:8e01dca41002 480 npcb->remote_port = tcphdr->src;
donatien 0:8e01dca41002 481 npcb->state = SYN_RCVD;
donatien 0:8e01dca41002 482 npcb->rcv_nxt = seqno + 1;
donatien 0:8e01dca41002 483 npcb->rcv_ann_right_edge = npcb->rcv_nxt;
donatien 0:8e01dca41002 484 npcb->snd_wnd = tcphdr->wnd;
donatien 0:8e01dca41002 485 npcb->ssthresh = npcb->snd_wnd;
donatien 0:8e01dca41002 486 npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
donatien 0:8e01dca41002 487 npcb->callback_arg = pcb->callback_arg;
donatien 0:8e01dca41002 488 #if LWIP_CALLBACK_API
donatien 0:8e01dca41002 489 npcb->accept = pcb->accept;
donatien 0:8e01dca41002 490 #endif /* LWIP_CALLBACK_API */
donatien 0:8e01dca41002 491 /* inherit socket options */
donatien 0:8e01dca41002 492 npcb->so_options = pcb->so_options & SOF_INHERITED;
donatien 0:8e01dca41002 493 /* Register the new PCB so that we can begin receiving segments
donatien 0:8e01dca41002 494 for it. */
donatien 0:8e01dca41002 495 TCP_REG(&tcp_active_pcbs, npcb);
donatien 0:8e01dca41002 496
donatien 0:8e01dca41002 497 /* Parse any options in the SYN. */
donatien 0:8e01dca41002 498 tcp_parseopt(npcb);
donatien 0:8e01dca41002 499 #if TCP_CALCULATE_EFF_SEND_MSS
donatien 0:8e01dca41002 500 npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
donatien 0:8e01dca41002 501 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
donatien 0:8e01dca41002 502
donatien 0:8e01dca41002 503 snmp_inc_tcppassiveopens();
donatien 0:8e01dca41002 504
donatien 0:8e01dca41002 505 /* Send a SYN|ACK together with the MSS option. */
donatien 0:8e01dca41002 506 rc = tcp_enqueue_flags(npcb, TCP_SYN | TCP_ACK);
donatien 0:8e01dca41002 507 if (rc != ERR_OK) {
donatien 0:8e01dca41002 508 tcp_abandon(npcb, 0);
donatien 0:8e01dca41002 509 return rc;
donatien 0:8e01dca41002 510 }
donatien 0:8e01dca41002 511 return tcp_output(npcb);
donatien 0:8e01dca41002 512 }
donatien 0:8e01dca41002 513 return ERR_OK;
donatien 0:8e01dca41002 514 }
donatien 0:8e01dca41002 515
donatien 0:8e01dca41002 516 /**
donatien 0:8e01dca41002 517 * Called by tcp_input() when a segment arrives for a connection in
donatien 0:8e01dca41002 518 * TIME_WAIT.
donatien 0:8e01dca41002 519 *
donatien 0:8e01dca41002 520 * @param pcb the tcp_pcb for which a segment arrived
donatien 0:8e01dca41002 521 *
donatien 0:8e01dca41002 522 * @note the segment which arrived is saved in global variables, therefore only the pcb
donatien 0:8e01dca41002 523 * involved is passed as a parameter to this function
donatien 0:8e01dca41002 524 */
donatien 0:8e01dca41002 525 static err_t
donatien 0:8e01dca41002 526 tcp_timewait_input(struct tcp_pcb *pcb)
donatien 0:8e01dca41002 527 {
donatien 0:8e01dca41002 528 /* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
donatien 0:8e01dca41002 529 /* RFC 793 3.9 Event Processing - Segment Arrives:
donatien 0:8e01dca41002 530 * - first check sequence number - we skip that one in TIME_WAIT (always
donatien 0:8e01dca41002 531 * acceptable since we only send ACKs)
donatien 0:8e01dca41002 532 * - second check the RST bit (... return) */
donatien 0:8e01dca41002 533 if (flags & TCP_RST) {
donatien 0:8e01dca41002 534 return ERR_OK;
donatien 0:8e01dca41002 535 }
donatien 0:8e01dca41002 536 /* - fourth, check the SYN bit, */
donatien 0:8e01dca41002 537 if (flags & TCP_SYN) {
donatien 0:8e01dca41002 538 /* If an incoming segment is not acceptable, an acknowledgment
donatien 0:8e01dca41002 539 should be sent in reply */
donatien 0:8e01dca41002 540 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
donatien 0:8e01dca41002 541 /* If the SYN is in the window it is an error, send a reset */
donatien 0:8e01dca41002 542 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
donatien 0:8e01dca41002 543 tcphdr->dest, tcphdr->src);
donatien 0:8e01dca41002 544 return ERR_OK;
donatien 0:8e01dca41002 545 }
donatien 0:8e01dca41002 546 } else if (flags & TCP_FIN) {
donatien 0:8e01dca41002 547 /* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
donatien 0:8e01dca41002 548 Restart the 2 MSL time-wait timeout.*/
donatien 0:8e01dca41002 549 pcb->tmr = tcp_ticks;
donatien 0:8e01dca41002 550 }
donatien 0:8e01dca41002 551
donatien 0:8e01dca41002 552 if ((tcplen > 0)) {
donatien 0:8e01dca41002 553 /* Acknowledge data, FIN or out-of-window SYN */
donatien 0:8e01dca41002 554 pcb->flags |= TF_ACK_NOW;
donatien 0:8e01dca41002 555 return tcp_output(pcb);
donatien 0:8e01dca41002 556 }
donatien 0:8e01dca41002 557 return ERR_OK;
donatien 0:8e01dca41002 558 }
donatien 0:8e01dca41002 559
donatien 0:8e01dca41002 560 /**
donatien 0:8e01dca41002 561 * Implements the TCP state machine. Called by tcp_input. In some
donatien 0:8e01dca41002 562 * states tcp_receive() is called to receive data. The tcp_seg
donatien 0:8e01dca41002 563 * argument will be freed by the caller (tcp_input()) unless the
donatien 0:8e01dca41002 564 * recv_data pointer in the pcb is set.
donatien 0:8e01dca41002 565 *
donatien 0:8e01dca41002 566 * @param pcb the tcp_pcb for which a segment arrived
donatien 0:8e01dca41002 567 *
donatien 0:8e01dca41002 568 * @note the segment which arrived is saved in global variables, therefore only the pcb
donatien 0:8e01dca41002 569 * involved is passed as a parameter to this function
donatien 0:8e01dca41002 570 */
donatien 0:8e01dca41002 571 static err_t
donatien 0:8e01dca41002 572 tcp_process(struct tcp_pcb *pcb)
donatien 0:8e01dca41002 573 {
donatien 0:8e01dca41002 574 struct tcp_seg *rseg;
donatien 0:8e01dca41002 575 u8_t acceptable = 0;
donatien 0:8e01dca41002 576 err_t err;
donatien 0:8e01dca41002 577
donatien 0:8e01dca41002 578 err = ERR_OK;
donatien 0:8e01dca41002 579
donatien 0:8e01dca41002 580 /* Process incoming RST segments. */
donatien 0:8e01dca41002 581 if (flags & TCP_RST) {
donatien 0:8e01dca41002 582 /* First, determine if the reset is acceptable. */
donatien 0:8e01dca41002 583 if (pcb->state == SYN_SENT) {
donatien 0:8e01dca41002 584 if (ackno == pcb->snd_nxt) {
donatien 0:8e01dca41002 585 acceptable = 1;
donatien 0:8e01dca41002 586 }
donatien 0:8e01dca41002 587 } else {
donatien 0:8e01dca41002 588 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
donatien 0:8e01dca41002 589 pcb->rcv_nxt+pcb->rcv_wnd)) {
donatien 0:8e01dca41002 590 acceptable = 1;
donatien 0:8e01dca41002 591 }
donatien 0:8e01dca41002 592 }
donatien 0:8e01dca41002 593
donatien 0:8e01dca41002 594 if (acceptable) {
donatien 0:8e01dca41002 595 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
donatien 0:8e01dca41002 596 LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
donatien 0:8e01dca41002 597 recv_flags |= TF_RESET;
donatien 0:8e01dca41002 598 pcb->flags &= ~TF_ACK_DELAY;
donatien 0:8e01dca41002 599 return ERR_RST;
donatien 0:8e01dca41002 600 } else {
donatien 0:8e01dca41002 601 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
donatien 0:8e01dca41002 602 seqno, pcb->rcv_nxt));
donatien 0:8e01dca41002 603 LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
donatien 0:8e01dca41002 604 seqno, pcb->rcv_nxt));
donatien 0:8e01dca41002 605 return ERR_OK;
donatien 0:8e01dca41002 606 }
donatien 0:8e01dca41002 607 }
donatien 0:8e01dca41002 608
donatien 0:8e01dca41002 609 if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
donatien 0:8e01dca41002 610 /* Cope with new connection attempt after remote end crashed */
donatien 0:8e01dca41002 611 tcp_ack_now(pcb);
donatien 0:8e01dca41002 612 return ERR_OK;
donatien 0:8e01dca41002 613 }
donatien 0:8e01dca41002 614
donatien 0:8e01dca41002 615 if ((pcb->flags & TF_RXCLOSED) == 0) {
donatien 0:8e01dca41002 616 /* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
donatien 0:8e01dca41002 617 pcb->tmr = tcp_ticks;
donatien 0:8e01dca41002 618 }
donatien 0:8e01dca41002 619 pcb->keep_cnt_sent = 0;
donatien 0:8e01dca41002 620
donatien 0:8e01dca41002 621 tcp_parseopt(pcb);
donatien 0:8e01dca41002 622
donatien 0:8e01dca41002 623 /* Do different things depending on the TCP state. */
donatien 0:8e01dca41002 624 switch (pcb->state) {
donatien 0:8e01dca41002 625 case SYN_SENT:
donatien 0:8e01dca41002 626 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
donatien 0:8e01dca41002 627 pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
donatien 0:8e01dca41002 628 /* received SYN ACK with expected sequence number? */
donatien 0:8e01dca41002 629 if ((flags & TCP_ACK) && (flags & TCP_SYN)
donatien 0:8e01dca41002 630 && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
donatien 0:8e01dca41002 631 pcb->snd_buf++;
donatien 0:8e01dca41002 632 pcb->rcv_nxt = seqno + 1;
donatien 0:8e01dca41002 633 pcb->rcv_ann_right_edge = pcb->rcv_nxt;
donatien 0:8e01dca41002 634 pcb->lastack = ackno;
donatien 0:8e01dca41002 635 pcb->snd_wnd = tcphdr->wnd;
donatien 0:8e01dca41002 636 pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
donatien 0:8e01dca41002 637 pcb->state = ESTABLISHED;
donatien 0:8e01dca41002 638
donatien 0:8e01dca41002 639 #if TCP_CALCULATE_EFF_SEND_MSS
donatien 0:8e01dca41002 640 pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
donatien 0:8e01dca41002 641 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
donatien 0:8e01dca41002 642
donatien 0:8e01dca41002 643 /* Set ssthresh again after changing pcb->mss (already set in tcp_connect
donatien 0:8e01dca41002 644 * but for the default value of pcb->mss) */
donatien 0:8e01dca41002 645 pcb->ssthresh = pcb->mss * 10;
donatien 0:8e01dca41002 646
donatien 0:8e01dca41002 647 pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
donatien 0:8e01dca41002 648 LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
donatien 0:8e01dca41002 649 --pcb->snd_queuelen;
donatien 0:8e01dca41002 650 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
donatien 0:8e01dca41002 651 rseg = pcb->unacked;
donatien 0:8e01dca41002 652 pcb->unacked = rseg->next;
donatien 0:8e01dca41002 653
donatien 0:8e01dca41002 654 /* If there's nothing left to acknowledge, stop the retransmit
donatien 0:8e01dca41002 655 timer, otherwise reset it to start again */
donatien 0:8e01dca41002 656 if(pcb->unacked == NULL)
donatien 0:8e01dca41002 657 pcb->rtime = -1;
donatien 0:8e01dca41002 658 else {
donatien 0:8e01dca41002 659 pcb->rtime = 0;
donatien 0:8e01dca41002 660 pcb->nrtx = 0;
donatien 0:8e01dca41002 661 }
donatien 0:8e01dca41002 662
donatien 0:8e01dca41002 663 tcp_seg_free(rseg);
donatien 0:8e01dca41002 664
donatien 0:8e01dca41002 665 /* Call the user specified function to call when sucessfully
donatien 0:8e01dca41002 666 * connected. */
donatien 0:8e01dca41002 667 TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
donatien 0:8e01dca41002 668 if (err == ERR_ABRT) {
donatien 0:8e01dca41002 669 return ERR_ABRT;
donatien 0:8e01dca41002 670 }
donatien 0:8e01dca41002 671 tcp_ack_now(pcb);
donatien 0:8e01dca41002 672 }
donatien 0:8e01dca41002 673 /* received ACK? possibly a half-open connection */
donatien 0:8e01dca41002 674 else if (flags & TCP_ACK) {
donatien 0:8e01dca41002 675 /* send a RST to bring the other side in a non-synchronized state. */
donatien 0:8e01dca41002 676 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
donatien 0:8e01dca41002 677 tcphdr->dest, tcphdr->src);
donatien 0:8e01dca41002 678 }
donatien 0:8e01dca41002 679 break;
donatien 0:8e01dca41002 680 case SYN_RCVD:
donatien 0:8e01dca41002 681 if (flags & TCP_ACK) {
donatien 0:8e01dca41002 682 /* expected ACK number? */
donatien 0:8e01dca41002 683 if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
donatien 0:8e01dca41002 684 u16_t old_cwnd;
donatien 0:8e01dca41002 685 pcb->state = ESTABLISHED;
donatien 0:8e01dca41002 686 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
donatien 0:8e01dca41002 687 #if LWIP_CALLBACK_API
donatien 0:8e01dca41002 688 LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
donatien 0:8e01dca41002 689 #endif
donatien 0:8e01dca41002 690 /* Call the accept function. */
donatien 0:8e01dca41002 691 TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
donatien 0:8e01dca41002 692 if (err != ERR_OK) {
donatien 0:8e01dca41002 693 /* If the accept function returns with an error, we abort
donatien 0:8e01dca41002 694 * the connection. */
donatien 0:8e01dca41002 695 /* Already aborted? */
donatien 0:8e01dca41002 696 if (err != ERR_ABRT) {
donatien 0:8e01dca41002 697 tcp_abort(pcb);
donatien 0:8e01dca41002 698 }
donatien 0:8e01dca41002 699 return ERR_ABRT;
donatien 0:8e01dca41002 700 }
donatien 0:8e01dca41002 701 old_cwnd = pcb->cwnd;
donatien 0:8e01dca41002 702 /* If there was any data contained within this ACK,
donatien 0:8e01dca41002 703 * we'd better pass it on to the application as well. */
donatien 0:8e01dca41002 704 tcp_receive(pcb);
donatien 0:8e01dca41002 705
donatien 0:8e01dca41002 706 /* Prevent ACK for SYN to generate a sent event */
donatien 0:8e01dca41002 707 if (pcb->acked != 0) {
donatien 0:8e01dca41002 708 pcb->acked--;
donatien 0:8e01dca41002 709 }
donatien 0:8e01dca41002 710
donatien 0:8e01dca41002 711 pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
donatien 0:8e01dca41002 712
donatien 0:8e01dca41002 713 if (recv_flags & TF_GOT_FIN) {
donatien 0:8e01dca41002 714 tcp_ack_now(pcb);
donatien 0:8e01dca41002 715 pcb->state = CLOSE_WAIT;
donatien 0:8e01dca41002 716 }
donatien 0:8e01dca41002 717 } else {
donatien 0:8e01dca41002 718 /* incorrect ACK number, send RST */
donatien 0:8e01dca41002 719 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
donatien 0:8e01dca41002 720 tcphdr->dest, tcphdr->src);
donatien 0:8e01dca41002 721 }
donatien 0:8e01dca41002 722 } else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
donatien 0:8e01dca41002 723 /* Looks like another copy of the SYN - retransmit our SYN-ACK */
donatien 0:8e01dca41002 724 tcp_rexmit(pcb);
donatien 0:8e01dca41002 725 }
donatien 0:8e01dca41002 726 break;
donatien 0:8e01dca41002 727 case CLOSE_WAIT:
donatien 0:8e01dca41002 728 /* FALLTHROUGH */
donatien 0:8e01dca41002 729 case ESTABLISHED:
donatien 0:8e01dca41002 730 tcp_receive(pcb);
donatien 0:8e01dca41002 731 if (recv_flags & TF_GOT_FIN) { /* passive close */
donatien 0:8e01dca41002 732 tcp_ack_now(pcb);
donatien 0:8e01dca41002 733 pcb->state = CLOSE_WAIT;
donatien 0:8e01dca41002 734 }
donatien 0:8e01dca41002 735 break;
donatien 0:8e01dca41002 736 case FIN_WAIT_1:
donatien 0:8e01dca41002 737 tcp_receive(pcb);
donatien 0:8e01dca41002 738 if (recv_flags & TF_GOT_FIN) {
donatien 0:8e01dca41002 739 if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
donatien 0:8e01dca41002 740 LWIP_DEBUGF(TCP_DEBUG,
donatien 0:8e01dca41002 741 ("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
donatien 0:8e01dca41002 742 tcp_ack_now(pcb);
donatien 0:8e01dca41002 743 tcp_pcb_purge(pcb);
donatien 0:8e01dca41002 744 TCP_RMV(&tcp_active_pcbs, pcb);
donatien 0:8e01dca41002 745 pcb->state = TIME_WAIT;
donatien 0:8e01dca41002 746 TCP_REG(&tcp_tw_pcbs, pcb);
donatien 0:8e01dca41002 747 } else {
donatien 0:8e01dca41002 748 tcp_ack_now(pcb);
donatien 0:8e01dca41002 749 pcb->state = CLOSING;
donatien 0:8e01dca41002 750 }
donatien 0:8e01dca41002 751 } else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
donatien 0:8e01dca41002 752 pcb->state = FIN_WAIT_2;
donatien 0:8e01dca41002 753 }
donatien 0:8e01dca41002 754 break;
donatien 0:8e01dca41002 755 case FIN_WAIT_2:
donatien 0:8e01dca41002 756 tcp_receive(pcb);
donatien 0:8e01dca41002 757 if (recv_flags & TF_GOT_FIN) {
donatien 0:8e01dca41002 758 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
donatien 0:8e01dca41002 759 tcp_ack_now(pcb);
donatien 0:8e01dca41002 760 tcp_pcb_purge(pcb);
donatien 0:8e01dca41002 761 TCP_RMV(&tcp_active_pcbs, pcb);
donatien 0:8e01dca41002 762 pcb->state = TIME_WAIT;
donatien 0:8e01dca41002 763 TCP_REG(&tcp_tw_pcbs, pcb);
donatien 0:8e01dca41002 764 }
donatien 0:8e01dca41002 765 break;
donatien 0:8e01dca41002 766 case CLOSING:
donatien 0:8e01dca41002 767 tcp_receive(pcb);
donatien 0:8e01dca41002 768 if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
donatien 0:8e01dca41002 769 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
donatien 0:8e01dca41002 770 tcp_pcb_purge(pcb);
donatien 0:8e01dca41002 771 TCP_RMV(&tcp_active_pcbs, pcb);
donatien 0:8e01dca41002 772 pcb->state = TIME_WAIT;
donatien 0:8e01dca41002 773 TCP_REG(&tcp_tw_pcbs, pcb);
donatien 0:8e01dca41002 774 }
donatien 0:8e01dca41002 775 break;
donatien 0:8e01dca41002 776 case LAST_ACK:
donatien 0:8e01dca41002 777 tcp_receive(pcb);
donatien 0:8e01dca41002 778 if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
donatien 0:8e01dca41002 779 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
donatien 0:8e01dca41002 780 /* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
donatien 0:8e01dca41002 781 recv_flags |= TF_CLOSED;
donatien 0:8e01dca41002 782 }
donatien 0:8e01dca41002 783 break;
donatien 0:8e01dca41002 784 default:
donatien 0:8e01dca41002 785 break;
donatien 0:8e01dca41002 786 }
donatien 0:8e01dca41002 787 return ERR_OK;
donatien 0:8e01dca41002 788 }
donatien 0:8e01dca41002 789
donatien 0:8e01dca41002 790 #if TCP_QUEUE_OOSEQ
donatien 0:8e01dca41002 791 /**
donatien 0:8e01dca41002 792 * Insert segment into the list (segments covered with new one will be deleted)
donatien 0:8e01dca41002 793 *
donatien 0:8e01dca41002 794 * Called from tcp_receive()
donatien 0:8e01dca41002 795 */
donatien 0:8e01dca41002 796 static void
donatien 0:8e01dca41002 797 tcp_oos_insert_segment(struct tcp_seg *cseg, struct tcp_seg *next)
donatien 0:8e01dca41002 798 {
donatien 0:8e01dca41002 799 struct tcp_seg *old_seg;
donatien 0:8e01dca41002 800
donatien 0:8e01dca41002 801 if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 802 /* received segment overlaps all following segments */
donatien 0:8e01dca41002 803 tcp_segs_free(next);
donatien 0:8e01dca41002 804 next = NULL;
donatien 0:8e01dca41002 805 }
donatien 0:8e01dca41002 806 else {
donatien 0:8e01dca41002 807 /* delete some following segments
donatien 0:8e01dca41002 808 oos queue may have segments with FIN flag */
donatien 0:8e01dca41002 809 while (next &&
donatien 0:8e01dca41002 810 TCP_SEQ_GEQ((seqno + cseg->len),
donatien 0:8e01dca41002 811 (next->tcphdr->seqno + next->len))) {
donatien 0:8e01dca41002 812 /* cseg with FIN already processed */
donatien 0:8e01dca41002 813 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 814 TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
donatien 0:8e01dca41002 815 }
donatien 0:8e01dca41002 816 old_seg = next;
donatien 0:8e01dca41002 817 next = next->next;
donatien 0:8e01dca41002 818 tcp_seg_free(old_seg);
donatien 0:8e01dca41002 819 }
donatien 0:8e01dca41002 820 if (next &&
donatien 0:8e01dca41002 821 TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
donatien 0:8e01dca41002 822 /* We need to trim the incoming segment. */
donatien 0:8e01dca41002 823 cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
donatien 0:8e01dca41002 824 pbuf_realloc(cseg->p, cseg->len);
donatien 0:8e01dca41002 825 }
donatien 0:8e01dca41002 826 }
donatien 0:8e01dca41002 827 cseg->next = next;
donatien 0:8e01dca41002 828 }
donatien 0:8e01dca41002 829 #endif /* TCP_QUEUE_OOSEQ */
donatien 0:8e01dca41002 830
donatien 0:8e01dca41002 831 /**
donatien 0:8e01dca41002 832 * Called by tcp_process. Checks if the given segment is an ACK for outstanding
donatien 0:8e01dca41002 833 * data, and if so frees the memory of the buffered data. Next, is places the
donatien 0:8e01dca41002 834 * segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
donatien 0:8e01dca41002 835 * is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
donatien 0:8e01dca41002 836 * i it has been removed from the buffer.
donatien 0:8e01dca41002 837 *
donatien 0:8e01dca41002 838 * If the incoming segment constitutes an ACK for a segment that was used for RTT
donatien 0:8e01dca41002 839 * estimation, the RTT is estimated here as well.
donatien 0:8e01dca41002 840 *
donatien 0:8e01dca41002 841 * Called from tcp_process().
donatien 0:8e01dca41002 842 */
donatien 0:8e01dca41002 843 static void
donatien 0:8e01dca41002 844 tcp_receive(struct tcp_pcb *pcb)
donatien 0:8e01dca41002 845 {
donatien 0:8e01dca41002 846 struct tcp_seg *next;
donatien 0:8e01dca41002 847 #if TCP_QUEUE_OOSEQ
donatien 0:8e01dca41002 848 struct tcp_seg *prev, *cseg;
donatien 0:8e01dca41002 849 #endif /* TCP_QUEUE_OOSEQ */
donatien 0:8e01dca41002 850 struct pbuf *p;
donatien 0:8e01dca41002 851 s32_t off;
donatien 0:8e01dca41002 852 s16_t m;
donatien 0:8e01dca41002 853 u32_t right_wnd_edge;
donatien 0:8e01dca41002 854 u16_t new_tot_len;
donatien 0:8e01dca41002 855 int found_dupack = 0;
donatien 0:8e01dca41002 856
donatien 0:8e01dca41002 857 if (flags & TCP_ACK) {
donatien 0:8e01dca41002 858 right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
donatien 0:8e01dca41002 859
donatien 0:8e01dca41002 860 /* Update window. */
donatien 0:8e01dca41002 861 if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
donatien 0:8e01dca41002 862 (pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
donatien 0:8e01dca41002 863 (pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
donatien 0:8e01dca41002 864 pcb->snd_wnd = tcphdr->wnd;
donatien 0:8e01dca41002 865 pcb->snd_wl1 = seqno;
donatien 0:8e01dca41002 866 pcb->snd_wl2 = ackno;
donatien 0:8e01dca41002 867 if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
donatien 0:8e01dca41002 868 pcb->persist_backoff = 0;
donatien 0:8e01dca41002 869 }
donatien 0:8e01dca41002 870 LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
donatien 0:8e01dca41002 871 #if TCP_WND_DEBUG
donatien 0:8e01dca41002 872 } else {
donatien 0:8e01dca41002 873 if (pcb->snd_wnd != tcphdr->wnd) {
donatien 0:8e01dca41002 874 LWIP_DEBUGF(TCP_WND_DEBUG,
donatien 0:8e01dca41002 875 ("tcp_receive: no window update lastack %"U32_F" ackno %"
donatien 0:8e01dca41002 876 U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
donatien 0:8e01dca41002 877 pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
donatien 0:8e01dca41002 878 }
donatien 0:8e01dca41002 879 #endif /* TCP_WND_DEBUG */
donatien 0:8e01dca41002 880 }
donatien 0:8e01dca41002 881
donatien 0:8e01dca41002 882 /* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
donatien 0:8e01dca41002 883 * duplicate ack if:
donatien 0:8e01dca41002 884 * 1) It doesn't ACK new data
donatien 0:8e01dca41002 885 * 2) length of received packet is zero (i.e. no payload)
donatien 0:8e01dca41002 886 * 3) the advertised window hasn't changed
donatien 0:8e01dca41002 887 * 4) There is outstanding unacknowledged data (retransmission timer running)
donatien 0:8e01dca41002 888 * 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
donatien 0:8e01dca41002 889 *
donatien 0:8e01dca41002 890 * If it passes all five, should process as a dupack:
donatien 0:8e01dca41002 891 * a) dupacks < 3: do nothing
donatien 0:8e01dca41002 892 * b) dupacks == 3: fast retransmit
donatien 0:8e01dca41002 893 * c) dupacks > 3: increase cwnd
donatien 0:8e01dca41002 894 *
donatien 0:8e01dca41002 895 * If it only passes 1-3, should reset dupack counter (and add to
donatien 0:8e01dca41002 896 * stats, which we don't do in lwIP)
donatien 0:8e01dca41002 897 *
donatien 0:8e01dca41002 898 * If it only passes 1, should reset dupack counter
donatien 0:8e01dca41002 899 *
donatien 0:8e01dca41002 900 */
donatien 0:8e01dca41002 901
donatien 0:8e01dca41002 902 /* Clause 1 */
donatien 0:8e01dca41002 903 if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
donatien 0:8e01dca41002 904 pcb->acked = 0;
donatien 0:8e01dca41002 905 /* Clause 2 */
donatien 0:8e01dca41002 906 if (tcplen == 0) {
donatien 0:8e01dca41002 907 /* Clause 3 */
donatien 0:8e01dca41002 908 if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
donatien 0:8e01dca41002 909 /* Clause 4 */
donatien 0:8e01dca41002 910 if (pcb->rtime >= 0) {
donatien 0:8e01dca41002 911 /* Clause 5 */
donatien 0:8e01dca41002 912 if (pcb->lastack == ackno) {
donatien 0:8e01dca41002 913 found_dupack = 1;
donatien 0:8e01dca41002 914 if (pcb->dupacks + 1 > pcb->dupacks)
donatien 0:8e01dca41002 915 ++pcb->dupacks;
donatien 0:8e01dca41002 916 if (pcb->dupacks > 3) {
donatien 0:8e01dca41002 917 /* Inflate the congestion window, but not if it means that
donatien 0:8e01dca41002 918 the value overflows. */
donatien 0:8e01dca41002 919 if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
donatien 0:8e01dca41002 920 pcb->cwnd += pcb->mss;
donatien 0:8e01dca41002 921 }
donatien 0:8e01dca41002 922 } else if (pcb->dupacks == 3) {
donatien 0:8e01dca41002 923 /* Do fast retransmit */
donatien 0:8e01dca41002 924 tcp_rexmit_fast(pcb);
donatien 0:8e01dca41002 925 }
donatien 0:8e01dca41002 926 }
donatien 0:8e01dca41002 927 }
donatien 0:8e01dca41002 928 }
donatien 0:8e01dca41002 929 }
donatien 0:8e01dca41002 930 /* If Clause (1) or more is true, but not a duplicate ack, reset
donatien 0:8e01dca41002 931 * count of consecutive duplicate acks */
donatien 0:8e01dca41002 932 if (!found_dupack) {
donatien 0:8e01dca41002 933 pcb->dupacks = 0;
donatien 0:8e01dca41002 934 }
donatien 0:8e01dca41002 935 } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
donatien 0:8e01dca41002 936 /* We come here when the ACK acknowledges new data. */
donatien 0:8e01dca41002 937
donatien 0:8e01dca41002 938 /* Reset the "IN Fast Retransmit" flag, since we are no longer
donatien 0:8e01dca41002 939 in fast retransmit. Also reset the congestion window to the
donatien 0:8e01dca41002 940 slow start threshold. */
donatien 0:8e01dca41002 941 if (pcb->flags & TF_INFR) {
donatien 0:8e01dca41002 942 pcb->flags &= ~TF_INFR;
donatien 0:8e01dca41002 943 pcb->cwnd = pcb->ssthresh;
donatien 0:8e01dca41002 944 }
donatien 0:8e01dca41002 945
donatien 0:8e01dca41002 946 /* Reset the number of retransmissions. */
donatien 0:8e01dca41002 947 pcb->nrtx = 0;
donatien 0:8e01dca41002 948
donatien 0:8e01dca41002 949 /* Reset the retransmission time-out. */
donatien 0:8e01dca41002 950 pcb->rto = (pcb->sa >> 3) + pcb->sv;
donatien 0:8e01dca41002 951
donatien 0:8e01dca41002 952 /* Update the send buffer space. Diff between the two can never exceed 64K? */
donatien 0:8e01dca41002 953 pcb->acked = (u16_t)(ackno - pcb->lastack);
donatien 0:8e01dca41002 954
donatien 0:8e01dca41002 955 pcb->snd_buf += pcb->acked;
donatien 0:8e01dca41002 956
donatien 0:8e01dca41002 957 /* Reset the fast retransmit variables. */
donatien 0:8e01dca41002 958 pcb->dupacks = 0;
donatien 0:8e01dca41002 959 pcb->lastack = ackno;
donatien 0:8e01dca41002 960
donatien 0:8e01dca41002 961 /* Update the congestion control variables (cwnd and
donatien 0:8e01dca41002 962 ssthresh). */
donatien 0:8e01dca41002 963 if (pcb->state >= ESTABLISHED) {
donatien 0:8e01dca41002 964 if (pcb->cwnd < pcb->ssthresh) {
donatien 0:8e01dca41002 965 if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
donatien 0:8e01dca41002 966 pcb->cwnd += pcb->mss;
donatien 0:8e01dca41002 967 }
donatien 0:8e01dca41002 968 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
donatien 0:8e01dca41002 969 } else {
donatien 0:8e01dca41002 970 u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
donatien 0:8e01dca41002 971 if (new_cwnd > pcb->cwnd) {
donatien 0:8e01dca41002 972 pcb->cwnd = new_cwnd;
donatien 0:8e01dca41002 973 }
donatien 0:8e01dca41002 974 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
donatien 0:8e01dca41002 975 }
donatien 0:8e01dca41002 976 }
donatien 0:8e01dca41002 977 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
donatien 0:8e01dca41002 978 ackno,
donatien 0:8e01dca41002 979 pcb->unacked != NULL?
donatien 0:8e01dca41002 980 ntohl(pcb->unacked->tcphdr->seqno): 0,
donatien 0:8e01dca41002 981 pcb->unacked != NULL?
donatien 0:8e01dca41002 982 ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
donatien 0:8e01dca41002 983
donatien 0:8e01dca41002 984 /* Remove segment from the unacknowledged list if the incoming
donatien 0:8e01dca41002 985 ACK acknowlegdes them. */
donatien 0:8e01dca41002 986 while (pcb->unacked != NULL &&
donatien 0:8e01dca41002 987 TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
donatien 0:8e01dca41002 988 TCP_TCPLEN(pcb->unacked), ackno)) {
donatien 0:8e01dca41002 989 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
donatien 0:8e01dca41002 990 ntohl(pcb->unacked->tcphdr->seqno),
donatien 0:8e01dca41002 991 ntohl(pcb->unacked->tcphdr->seqno) +
donatien 0:8e01dca41002 992 TCP_TCPLEN(pcb->unacked)));
donatien 0:8e01dca41002 993
donatien 0:8e01dca41002 994 next = pcb->unacked;
donatien 0:8e01dca41002 995 pcb->unacked = pcb->unacked->next;
donatien 0:8e01dca41002 996
donatien 0:8e01dca41002 997 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
donatien 0:8e01dca41002 998 LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
donatien 0:8e01dca41002 999 /* Prevent ACK for FIN to generate a sent event */
donatien 0:8e01dca41002 1000 if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
donatien 0:8e01dca41002 1001 pcb->acked--;
donatien 0:8e01dca41002 1002 }
donatien 0:8e01dca41002 1003
donatien 0:8e01dca41002 1004 pcb->snd_queuelen -= pbuf_clen(next->p);
donatien 0:8e01dca41002 1005 tcp_seg_free(next);
donatien 0:8e01dca41002 1006
donatien 0:8e01dca41002 1007 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
donatien 0:8e01dca41002 1008 if (pcb->snd_queuelen != 0) {
donatien 0:8e01dca41002 1009 LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
donatien 0:8e01dca41002 1010 pcb->unsent != NULL);
donatien 0:8e01dca41002 1011 }
donatien 0:8e01dca41002 1012 }
donatien 0:8e01dca41002 1013
donatien 0:8e01dca41002 1014 /* If there's nothing left to acknowledge, stop the retransmit
donatien 0:8e01dca41002 1015 timer, otherwise reset it to start again */
donatien 0:8e01dca41002 1016 if(pcb->unacked == NULL)
donatien 0:8e01dca41002 1017 pcb->rtime = -1;
donatien 0:8e01dca41002 1018 else
donatien 0:8e01dca41002 1019 pcb->rtime = 0;
donatien 0:8e01dca41002 1020
donatien 0:8e01dca41002 1021 pcb->polltmr = 0;
donatien 0:8e01dca41002 1022 } else {
donatien 0:8e01dca41002 1023 /* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
donatien 0:8e01dca41002 1024 pcb->acked = 0;
donatien 0:8e01dca41002 1025 }
donatien 0:8e01dca41002 1026
donatien 0:8e01dca41002 1027 /* We go through the ->unsent list to see if any of the segments
donatien 0:8e01dca41002 1028 on the list are acknowledged by the ACK. This may seem
donatien 0:8e01dca41002 1029 strange since an "unsent" segment shouldn't be acked. The
donatien 0:8e01dca41002 1030 rationale is that lwIP puts all outstanding segments on the
donatien 0:8e01dca41002 1031 ->unsent list after a retransmission, so these segments may
donatien 0:8e01dca41002 1032 in fact have been sent once. */
donatien 0:8e01dca41002 1033 while (pcb->unsent != NULL &&
donatien 0:8e01dca41002 1034 TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
donatien 0:8e01dca41002 1035 TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
donatien 0:8e01dca41002 1036 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
donatien 0:8e01dca41002 1037 ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
donatien 0:8e01dca41002 1038 TCP_TCPLEN(pcb->unsent)));
donatien 0:8e01dca41002 1039
donatien 0:8e01dca41002 1040 next = pcb->unsent;
donatien 0:8e01dca41002 1041 pcb->unsent = pcb->unsent->next;
donatien 0:8e01dca41002 1042 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
donatien 0:8e01dca41002 1043 LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
donatien 0:8e01dca41002 1044 /* Prevent ACK for FIN to generate a sent event */
donatien 0:8e01dca41002 1045 if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
donatien 0:8e01dca41002 1046 pcb->acked--;
donatien 0:8e01dca41002 1047 }
donatien 0:8e01dca41002 1048 pcb->snd_queuelen -= pbuf_clen(next->p);
donatien 0:8e01dca41002 1049 tcp_seg_free(next);
donatien 0:8e01dca41002 1050 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
donatien 0:8e01dca41002 1051 if (pcb->snd_queuelen != 0) {
donatien 0:8e01dca41002 1052 LWIP_ASSERT("tcp_receive: valid queue length",
donatien 0:8e01dca41002 1053 pcb->unacked != NULL || pcb->unsent != NULL);
donatien 0:8e01dca41002 1054 }
donatien 0:8e01dca41002 1055 }
donatien 0:8e01dca41002 1056 /* End of ACK for new data processing. */
donatien 0:8e01dca41002 1057
donatien 0:8e01dca41002 1058 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
donatien 0:8e01dca41002 1059 pcb->rttest, pcb->rtseq, ackno));
donatien 0:8e01dca41002 1060
donatien 0:8e01dca41002 1061 /* RTT estimation calculations. This is done by checking if the
donatien 0:8e01dca41002 1062 incoming segment acknowledges the segment we use to take a
donatien 0:8e01dca41002 1063 round-trip time measurement. */
donatien 0:8e01dca41002 1064 if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
donatien 0:8e01dca41002 1065 /* diff between this shouldn't exceed 32K since this are tcp timer ticks
donatien 0:8e01dca41002 1066 and a round-trip shouldn't be that long... */
donatien 0:8e01dca41002 1067 m = (s16_t)(tcp_ticks - pcb->rttest);
donatien 0:8e01dca41002 1068
donatien 0:8e01dca41002 1069 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
donatien 0:8e01dca41002 1070 m, m * TCP_SLOW_INTERVAL));
donatien 0:8e01dca41002 1071
donatien 0:8e01dca41002 1072 /* This is taken directly from VJs original code in his paper */
donatien 0:8e01dca41002 1073 m = m - (pcb->sa >> 3);
donatien 0:8e01dca41002 1074 pcb->sa += m;
donatien 0:8e01dca41002 1075 if (m < 0) {
donatien 0:8e01dca41002 1076 m = -m;
donatien 0:8e01dca41002 1077 }
donatien 0:8e01dca41002 1078 m = m - (pcb->sv >> 2);
donatien 0:8e01dca41002 1079 pcb->sv += m;
donatien 0:8e01dca41002 1080 pcb->rto = (pcb->sa >> 3) + pcb->sv;
donatien 0:8e01dca41002 1081
donatien 0:8e01dca41002 1082 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
donatien 0:8e01dca41002 1083 pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
donatien 0:8e01dca41002 1084
donatien 0:8e01dca41002 1085 pcb->rttest = 0;
donatien 0:8e01dca41002 1086 }
donatien 0:8e01dca41002 1087 }
donatien 0:8e01dca41002 1088
donatien 0:8e01dca41002 1089 /* If the incoming segment contains data, we must process it
donatien 0:8e01dca41002 1090 further. */
donatien 0:8e01dca41002 1091 if (tcplen > 0) {
donatien 0:8e01dca41002 1092 /* This code basically does three things:
donatien 0:8e01dca41002 1093
donatien 0:8e01dca41002 1094 +) If the incoming segment contains data that is the next
donatien 0:8e01dca41002 1095 in-sequence data, this data is passed to the application. This
donatien 0:8e01dca41002 1096 might involve trimming the first edge of the data. The rcv_nxt
donatien 0:8e01dca41002 1097 variable and the advertised window are adjusted.
donatien 0:8e01dca41002 1098
donatien 0:8e01dca41002 1099 +) If the incoming segment has data that is above the next
donatien 0:8e01dca41002 1100 sequence number expected (->rcv_nxt), the segment is placed on
donatien 0:8e01dca41002 1101 the ->ooseq queue. This is done by finding the appropriate
donatien 0:8e01dca41002 1102 place in the ->ooseq queue (which is ordered by sequence
donatien 0:8e01dca41002 1103 number) and trim the segment in both ends if needed. An
donatien 0:8e01dca41002 1104 immediate ACK is sent to indicate that we received an
donatien 0:8e01dca41002 1105 out-of-sequence segment.
donatien 0:8e01dca41002 1106
donatien 0:8e01dca41002 1107 +) Finally, we check if the first segment on the ->ooseq queue
donatien 0:8e01dca41002 1108 now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
donatien 0:8e01dca41002 1109 rcv_nxt > ooseq->seqno, we must trim the first edge of the
donatien 0:8e01dca41002 1110 segment on ->ooseq before we adjust rcv_nxt. The data in the
donatien 0:8e01dca41002 1111 segments that are now on sequence are chained onto the
donatien 0:8e01dca41002 1112 incoming segment so that we only need to call the application
donatien 0:8e01dca41002 1113 once.
donatien 0:8e01dca41002 1114 */
donatien 0:8e01dca41002 1115
donatien 0:8e01dca41002 1116 /* First, we check if we must trim the first edge. We have to do
donatien 0:8e01dca41002 1117 this if the sequence number of the incoming segment is less
donatien 0:8e01dca41002 1118 than rcv_nxt, and the sequence number plus the length of the
donatien 0:8e01dca41002 1119 segment is larger than rcv_nxt. */
donatien 0:8e01dca41002 1120 /* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
donatien 0:8e01dca41002 1121 if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
donatien 0:8e01dca41002 1122 if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
donatien 0:8e01dca41002 1123 /* Trimming the first edge is done by pushing the payload
donatien 0:8e01dca41002 1124 pointer in the pbuf downwards. This is somewhat tricky since
donatien 0:8e01dca41002 1125 we do not want to discard the full contents of the pbuf up to
donatien 0:8e01dca41002 1126 the new starting point of the data since we have to keep the
donatien 0:8e01dca41002 1127 TCP header which is present in the first pbuf in the chain.
donatien 0:8e01dca41002 1128
donatien 0:8e01dca41002 1129 What is done is really quite a nasty hack: the first pbuf in
donatien 0:8e01dca41002 1130 the pbuf chain is pointed to by inseg.p. Since we need to be
donatien 0:8e01dca41002 1131 able to deallocate the whole pbuf, we cannot change this
donatien 0:8e01dca41002 1132 inseg.p pointer to point to any of the later pbufs in the
donatien 0:8e01dca41002 1133 chain. Instead, we point the ->payload pointer in the first
donatien 0:8e01dca41002 1134 pbuf to data in one of the later pbufs. We also set the
donatien 0:8e01dca41002 1135 inseg.data pointer to point to the right place. This way, the
donatien 0:8e01dca41002 1136 ->p pointer will still point to the first pbuf, but the
donatien 0:8e01dca41002 1137 ->p->payload pointer will point to data in another pbuf.
donatien 0:8e01dca41002 1138
donatien 0:8e01dca41002 1139 After we are done with adjusting the pbuf pointers we must
donatien 0:8e01dca41002 1140 adjust the ->data pointer in the seg and the segment
donatien 0:8e01dca41002 1141 length.*/
donatien 0:8e01dca41002 1142
donatien 0:8e01dca41002 1143 off = pcb->rcv_nxt - seqno;
donatien 0:8e01dca41002 1144 p = inseg.p;
donatien 0:8e01dca41002 1145 LWIP_ASSERT("inseg.p != NULL", inseg.p);
donatien 0:8e01dca41002 1146 LWIP_ASSERT("insane offset!", (off < 0x7fff));
donatien 0:8e01dca41002 1147 if (inseg.p->len < off) {
donatien 0:8e01dca41002 1148 LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
donatien 0:8e01dca41002 1149 new_tot_len = (u16_t)(inseg.p->tot_len - off);
donatien 0:8e01dca41002 1150 while (p->len < off) {
donatien 0:8e01dca41002 1151 off -= p->len;
donatien 0:8e01dca41002 1152 /* KJM following line changed (with addition of new_tot_len var)
donatien 0:8e01dca41002 1153 to fix bug #9076
donatien 0:8e01dca41002 1154 inseg.p->tot_len -= p->len; */
donatien 0:8e01dca41002 1155 p->tot_len = new_tot_len;
donatien 0:8e01dca41002 1156 p->len = 0;
donatien 0:8e01dca41002 1157 p = p->next;
donatien 0:8e01dca41002 1158 }
donatien 0:8e01dca41002 1159 if(pbuf_header(p, (s16_t)-off)) {
donatien 0:8e01dca41002 1160 /* Do we need to cope with this failing? Assert for now */
donatien 0:8e01dca41002 1161 LWIP_ASSERT("pbuf_header failed", 0);
donatien 0:8e01dca41002 1162 }
donatien 0:8e01dca41002 1163 } else {
donatien 0:8e01dca41002 1164 if(pbuf_header(inseg.p, (s16_t)-off)) {
donatien 0:8e01dca41002 1165 /* Do we need to cope with this failing? Assert for now */
donatien 0:8e01dca41002 1166 LWIP_ASSERT("pbuf_header failed", 0);
donatien 0:8e01dca41002 1167 }
donatien 0:8e01dca41002 1168 }
donatien 0:8e01dca41002 1169 inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
donatien 0:8e01dca41002 1170 inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
donatien 0:8e01dca41002 1171 }
donatien 0:8e01dca41002 1172 else {
donatien 0:8e01dca41002 1173 if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
donatien 0:8e01dca41002 1174 /* the whole segment is < rcv_nxt */
donatien 0:8e01dca41002 1175 /* must be a duplicate of a packet that has already been correctly handled */
donatien 0:8e01dca41002 1176
donatien 0:8e01dca41002 1177 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
donatien 0:8e01dca41002 1178 tcp_ack_now(pcb);
donatien 0:8e01dca41002 1179 }
donatien 0:8e01dca41002 1180 }
donatien 0:8e01dca41002 1181
donatien 0:8e01dca41002 1182 /* The sequence number must be within the window (above rcv_nxt
donatien 0:8e01dca41002 1183 and below rcv_nxt + rcv_wnd) in order to be further
donatien 0:8e01dca41002 1184 processed. */
donatien 0:8e01dca41002 1185 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
donatien 0:8e01dca41002 1186 pcb->rcv_nxt + pcb->rcv_wnd - 1)){
donatien 0:8e01dca41002 1187 if (pcb->rcv_nxt == seqno) {
donatien 0:8e01dca41002 1188 /* The incoming segment is the next in sequence. We check if
donatien 0:8e01dca41002 1189 we have to trim the end of the segment and update rcv_nxt
donatien 0:8e01dca41002 1190 and pass the data to the application. */
donatien 0:8e01dca41002 1191 tcplen = TCP_TCPLEN(&inseg);
donatien 0:8e01dca41002 1192
donatien 0:8e01dca41002 1193 if (tcplen > pcb->rcv_wnd) {
donatien 0:8e01dca41002 1194 LWIP_DEBUGF(TCP_INPUT_DEBUG,
donatien 0:8e01dca41002 1195 ("tcp_receive: other end overran receive window"
donatien 0:8e01dca41002 1196 "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
donatien 0:8e01dca41002 1197 seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
donatien 0:8e01dca41002 1198 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1199 /* Must remove the FIN from the header as we're trimming
donatien 0:8e01dca41002 1200 * that byte of sequence-space from the packet */
donatien 0:8e01dca41002 1201 TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
donatien 0:8e01dca41002 1202 }
donatien 0:8e01dca41002 1203 /* Adjust length of segment to fit in the window. */
donatien 0:8e01dca41002 1204 inseg.len = pcb->rcv_wnd;
donatien 0:8e01dca41002 1205 if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
donatien 0:8e01dca41002 1206 inseg.len -= 1;
donatien 0:8e01dca41002 1207 }
donatien 0:8e01dca41002 1208 pbuf_realloc(inseg.p, inseg.len);
donatien 0:8e01dca41002 1209 tcplen = TCP_TCPLEN(&inseg);
donatien 0:8e01dca41002 1210 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
donatien 0:8e01dca41002 1211 (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
donatien 0:8e01dca41002 1212 }
donatien 0:8e01dca41002 1213 #if TCP_QUEUE_OOSEQ
donatien 0:8e01dca41002 1214 /* Received in-sequence data, adjust ooseq data if:
donatien 0:8e01dca41002 1215 - FIN has been received or
donatien 0:8e01dca41002 1216 - inseq overlaps with ooseq */
donatien 0:8e01dca41002 1217 if (pcb->ooseq != NULL) {
donatien 0:8e01dca41002 1218 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1219 LWIP_DEBUGF(TCP_INPUT_DEBUG,
donatien 0:8e01dca41002 1220 ("tcp_receive: received in-order FIN, binning ooseq queue\n"));
donatien 0:8e01dca41002 1221 /* Received in-order FIN means anything that was received
donatien 0:8e01dca41002 1222 * out of order must now have been received in-order, so
donatien 0:8e01dca41002 1223 * bin the ooseq queue */
donatien 0:8e01dca41002 1224 while (pcb->ooseq != NULL) {
donatien 0:8e01dca41002 1225 struct tcp_seg *old_ooseq = pcb->ooseq;
donatien 0:8e01dca41002 1226 pcb->ooseq = pcb->ooseq->next;
donatien 0:8e01dca41002 1227 tcp_seg_free(old_ooseq);
donatien 0:8e01dca41002 1228 }
donatien 0:8e01dca41002 1229 }
donatien 0:8e01dca41002 1230 else {
donatien 0:8e01dca41002 1231 next = pcb->ooseq;
donatien 0:8e01dca41002 1232 /* Remove all segments on ooseq that are covered by inseg already.
donatien 0:8e01dca41002 1233 * FIN is copied from ooseq to inseg if present. */
donatien 0:8e01dca41002 1234 while (next &&
donatien 0:8e01dca41002 1235 TCP_SEQ_GEQ(seqno + tcplen,
donatien 0:8e01dca41002 1236 next->tcphdr->seqno + next->len)) {
donatien 0:8e01dca41002 1237 /* inseg cannot have FIN here (already processed above) */
donatien 0:8e01dca41002 1238 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
donatien 0:8e01dca41002 1239 (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
donatien 0:8e01dca41002 1240 TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
donatien 0:8e01dca41002 1241 tcplen = TCP_TCPLEN(&inseg);
donatien 0:8e01dca41002 1242 }
donatien 0:8e01dca41002 1243 prev = next;
donatien 0:8e01dca41002 1244 next = next->next;
donatien 0:8e01dca41002 1245 tcp_seg_free(prev);
donatien 0:8e01dca41002 1246 }
donatien 0:8e01dca41002 1247 /* Now trim right side of inseg if it overlaps with the first
donatien 0:8e01dca41002 1248 * segment on ooseq */
donatien 0:8e01dca41002 1249 if (next &&
donatien 0:8e01dca41002 1250 TCP_SEQ_GT(seqno + tcplen,
donatien 0:8e01dca41002 1251 next->tcphdr->seqno)) {
donatien 0:8e01dca41002 1252 /* inseg cannot have FIN here (already processed above) */
donatien 0:8e01dca41002 1253 inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
donatien 0:8e01dca41002 1254 if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
donatien 0:8e01dca41002 1255 inseg.len -= 1;
donatien 0:8e01dca41002 1256 }
donatien 0:8e01dca41002 1257 pbuf_realloc(inseg.p, inseg.len);
donatien 0:8e01dca41002 1258 tcplen = TCP_TCPLEN(&inseg);
donatien 0:8e01dca41002 1259 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
donatien 0:8e01dca41002 1260 (seqno + tcplen) == next->tcphdr->seqno);
donatien 0:8e01dca41002 1261 }
donatien 0:8e01dca41002 1262 pcb->ooseq = next;
donatien 0:8e01dca41002 1263 }
donatien 0:8e01dca41002 1264 }
donatien 0:8e01dca41002 1265 #endif /* TCP_QUEUE_OOSEQ */
donatien 0:8e01dca41002 1266
donatien 0:8e01dca41002 1267 pcb->rcv_nxt = seqno + tcplen;
donatien 0:8e01dca41002 1268
donatien 0:8e01dca41002 1269 /* Update the receiver's (our) window. */
donatien 0:8e01dca41002 1270 LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
donatien 0:8e01dca41002 1271 pcb->rcv_wnd -= tcplen;
donatien 0:8e01dca41002 1272
donatien 0:8e01dca41002 1273 tcp_update_rcv_ann_wnd(pcb);
donatien 0:8e01dca41002 1274
donatien 0:8e01dca41002 1275 /* If there is data in the segment, we make preparations to
donatien 0:8e01dca41002 1276 pass this up to the application. The ->recv_data variable
donatien 0:8e01dca41002 1277 is used for holding the pbuf that goes to the
donatien 0:8e01dca41002 1278 application. The code for reassembling out-of-sequence data
donatien 0:8e01dca41002 1279 chains its data on this pbuf as well.
donatien 0:8e01dca41002 1280
donatien 0:8e01dca41002 1281 If the segment was a FIN, we set the TF_GOT_FIN flag that will
donatien 0:8e01dca41002 1282 be used to indicate to the application that the remote side has
donatien 0:8e01dca41002 1283 closed its end of the connection. */
donatien 0:8e01dca41002 1284 if (inseg.p->tot_len > 0) {
donatien 0:8e01dca41002 1285 recv_data = inseg.p;
donatien 0:8e01dca41002 1286 /* Since this pbuf now is the responsibility of the
donatien 0:8e01dca41002 1287 application, we delete our reference to it so that we won't
donatien 0:8e01dca41002 1288 (mistakingly) deallocate it. */
donatien 0:8e01dca41002 1289 inseg.p = NULL;
donatien 0:8e01dca41002 1290 }
donatien 0:8e01dca41002 1291 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1292 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
donatien 0:8e01dca41002 1293 recv_flags |= TF_GOT_FIN;
donatien 0:8e01dca41002 1294 }
donatien 0:8e01dca41002 1295
donatien 0:8e01dca41002 1296 #if TCP_QUEUE_OOSEQ
donatien 0:8e01dca41002 1297 /* We now check if we have segments on the ->ooseq queue that
donatien 0:8e01dca41002 1298 are now in sequence. */
donatien 0:8e01dca41002 1299 while (pcb->ooseq != NULL &&
donatien 0:8e01dca41002 1300 pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
donatien 0:8e01dca41002 1301
donatien 0:8e01dca41002 1302 cseg = pcb->ooseq;
donatien 0:8e01dca41002 1303 seqno = pcb->ooseq->tcphdr->seqno;
donatien 0:8e01dca41002 1304
donatien 0:8e01dca41002 1305 pcb->rcv_nxt += TCP_TCPLEN(cseg);
donatien 0:8e01dca41002 1306 LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
donatien 0:8e01dca41002 1307 pcb->rcv_wnd >= TCP_TCPLEN(cseg));
donatien 0:8e01dca41002 1308 pcb->rcv_wnd -= TCP_TCPLEN(cseg);
donatien 0:8e01dca41002 1309
donatien 0:8e01dca41002 1310 tcp_update_rcv_ann_wnd(pcb);
donatien 0:8e01dca41002 1311
donatien 0:8e01dca41002 1312 if (cseg->p->tot_len > 0) {
donatien 0:8e01dca41002 1313 /* Chain this pbuf onto the pbuf that we will pass to
donatien 0:8e01dca41002 1314 the application. */
donatien 0:8e01dca41002 1315 if (recv_data) {
donatien 0:8e01dca41002 1316 pbuf_cat(recv_data, cseg->p);
donatien 0:8e01dca41002 1317 } else {
donatien 0:8e01dca41002 1318 recv_data = cseg->p;
donatien 0:8e01dca41002 1319 }
donatien 0:8e01dca41002 1320 cseg->p = NULL;
donatien 0:8e01dca41002 1321 }
donatien 0:8e01dca41002 1322 if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1323 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
donatien 0:8e01dca41002 1324 recv_flags |= TF_GOT_FIN;
donatien 0:8e01dca41002 1325 if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
donatien 0:8e01dca41002 1326 pcb->state = CLOSE_WAIT;
donatien 0:8e01dca41002 1327 }
donatien 0:8e01dca41002 1328 }
donatien 0:8e01dca41002 1329
donatien 0:8e01dca41002 1330 pcb->ooseq = cseg->next;
donatien 0:8e01dca41002 1331 tcp_seg_free(cseg);
donatien 0:8e01dca41002 1332 }
donatien 0:8e01dca41002 1333 #endif /* TCP_QUEUE_OOSEQ */
donatien 0:8e01dca41002 1334
donatien 0:8e01dca41002 1335
donatien 0:8e01dca41002 1336 /* Acknowledge the segment(s). */
donatien 0:8e01dca41002 1337 tcp_ack(pcb);
donatien 0:8e01dca41002 1338
donatien 0:8e01dca41002 1339 } else {
donatien 0:8e01dca41002 1340 /* We get here if the incoming segment is out-of-sequence. */
donatien 0:8e01dca41002 1341 tcp_send_empty_ack(pcb);
donatien 0:8e01dca41002 1342 #if TCP_QUEUE_OOSEQ
donatien 0:8e01dca41002 1343 /* We queue the segment on the ->ooseq queue. */
donatien 0:8e01dca41002 1344 if (pcb->ooseq == NULL) {
donatien 0:8e01dca41002 1345 pcb->ooseq = tcp_seg_copy(&inseg);
donatien 0:8e01dca41002 1346 } else {
donatien 0:8e01dca41002 1347 /* If the queue is not empty, we walk through the queue and
donatien 0:8e01dca41002 1348 try to find a place where the sequence number of the
donatien 0:8e01dca41002 1349 incoming segment is between the sequence numbers of the
donatien 0:8e01dca41002 1350 previous and the next segment on the ->ooseq queue. That is
donatien 0:8e01dca41002 1351 the place where we put the incoming segment. If needed, we
donatien 0:8e01dca41002 1352 trim the second edges of the previous and the incoming
donatien 0:8e01dca41002 1353 segment so that it will fit into the sequence.
donatien 0:8e01dca41002 1354
donatien 0:8e01dca41002 1355 If the incoming segment has the same sequence number as a
donatien 0:8e01dca41002 1356 segment on the ->ooseq queue, we discard the segment that
donatien 0:8e01dca41002 1357 contains less data. */
donatien 0:8e01dca41002 1358
donatien 0:8e01dca41002 1359 prev = NULL;
donatien 0:8e01dca41002 1360 for(next = pcb->ooseq; next != NULL; next = next->next) {
donatien 0:8e01dca41002 1361 if (seqno == next->tcphdr->seqno) {
donatien 0:8e01dca41002 1362 /* The sequence number of the incoming segment is the
donatien 0:8e01dca41002 1363 same as the sequence number of the segment on
donatien 0:8e01dca41002 1364 ->ooseq. We check the lengths to see which one to
donatien 0:8e01dca41002 1365 discard. */
donatien 0:8e01dca41002 1366 if (inseg.len > next->len) {
donatien 0:8e01dca41002 1367 /* The incoming segment is larger than the old
donatien 0:8e01dca41002 1368 segment. We replace some segments with the new
donatien 0:8e01dca41002 1369 one. */
donatien 0:8e01dca41002 1370 cseg = tcp_seg_copy(&inseg);
donatien 0:8e01dca41002 1371 if (cseg != NULL) {
donatien 0:8e01dca41002 1372 if (prev != NULL) {
donatien 0:8e01dca41002 1373 prev->next = cseg;
donatien 0:8e01dca41002 1374 } else {
donatien 0:8e01dca41002 1375 pcb->ooseq = cseg;
donatien 0:8e01dca41002 1376 }
donatien 0:8e01dca41002 1377 tcp_oos_insert_segment(cseg, next);
donatien 0:8e01dca41002 1378 }
donatien 0:8e01dca41002 1379 break;
donatien 0:8e01dca41002 1380 } else {
donatien 0:8e01dca41002 1381 /* Either the lenghts are the same or the incoming
donatien 0:8e01dca41002 1382 segment was smaller than the old one; in either
donatien 0:8e01dca41002 1383 case, we ditch the incoming segment. */
donatien 0:8e01dca41002 1384 break;
donatien 0:8e01dca41002 1385 }
donatien 0:8e01dca41002 1386 } else {
donatien 0:8e01dca41002 1387 if (prev == NULL) {
donatien 0:8e01dca41002 1388 if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
donatien 0:8e01dca41002 1389 /* The sequence number of the incoming segment is lower
donatien 0:8e01dca41002 1390 than the sequence number of the first segment on the
donatien 0:8e01dca41002 1391 queue. We put the incoming segment first on the
donatien 0:8e01dca41002 1392 queue. */
donatien 0:8e01dca41002 1393 cseg = tcp_seg_copy(&inseg);
donatien 0:8e01dca41002 1394 if (cseg != NULL) {
donatien 0:8e01dca41002 1395 pcb->ooseq = cseg;
donatien 0:8e01dca41002 1396 tcp_oos_insert_segment(cseg, next);
donatien 0:8e01dca41002 1397 }
donatien 0:8e01dca41002 1398 break;
donatien 0:8e01dca41002 1399 }
donatien 0:8e01dca41002 1400 } else {
donatien 0:8e01dca41002 1401 /*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
donatien 0:8e01dca41002 1402 TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
donatien 0:8e01dca41002 1403 if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
donatien 0:8e01dca41002 1404 /* The sequence number of the incoming segment is in
donatien 0:8e01dca41002 1405 between the sequence numbers of the previous and
donatien 0:8e01dca41002 1406 the next segment on ->ooseq. We trim trim the previous
donatien 0:8e01dca41002 1407 segment, delete next segments that included in received segment
donatien 0:8e01dca41002 1408 and trim received, if needed. */
donatien 0:8e01dca41002 1409 cseg = tcp_seg_copy(&inseg);
donatien 0:8e01dca41002 1410 if (cseg != NULL) {
donatien 0:8e01dca41002 1411 if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
donatien 0:8e01dca41002 1412 /* We need to trim the prev segment. */
donatien 0:8e01dca41002 1413 prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
donatien 0:8e01dca41002 1414 pbuf_realloc(prev->p, prev->len);
donatien 0:8e01dca41002 1415 }
donatien 0:8e01dca41002 1416 prev->next = cseg;
donatien 0:8e01dca41002 1417 tcp_oos_insert_segment(cseg, next);
donatien 0:8e01dca41002 1418 }
donatien 0:8e01dca41002 1419 break;
donatien 0:8e01dca41002 1420 }
donatien 0:8e01dca41002 1421 }
donatien 0:8e01dca41002 1422 /* If the "next" segment is the last segment on the
donatien 0:8e01dca41002 1423 ooseq queue, we add the incoming segment to the end
donatien 0:8e01dca41002 1424 of the list. */
donatien 0:8e01dca41002 1425 if (next->next == NULL &&
donatien 0:8e01dca41002 1426 TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
donatien 0:8e01dca41002 1427 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1428 /* segment "next" already contains all data */
donatien 0:8e01dca41002 1429 break;
donatien 0:8e01dca41002 1430 }
donatien 0:8e01dca41002 1431 next->next = tcp_seg_copy(&inseg);
donatien 0:8e01dca41002 1432 if (next->next != NULL) {
donatien 0:8e01dca41002 1433 if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
donatien 0:8e01dca41002 1434 /* We need to trim the last segment. */
donatien 0:8e01dca41002 1435 next->len = (u16_t)(seqno - next->tcphdr->seqno);
donatien 0:8e01dca41002 1436 pbuf_realloc(next->p, next->len);
donatien 0:8e01dca41002 1437 }
donatien 0:8e01dca41002 1438 /* check if the remote side overruns our receive window */
donatien 0:8e01dca41002 1439 if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
donatien 0:8e01dca41002 1440 LWIP_DEBUGF(TCP_INPUT_DEBUG,
donatien 0:8e01dca41002 1441 ("tcp_receive: other end overran receive window"
donatien 0:8e01dca41002 1442 "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
donatien 0:8e01dca41002 1443 seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
donatien 0:8e01dca41002 1444 if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
donatien 0:8e01dca41002 1445 /* Must remove the FIN from the header as we're trimming
donatien 0:8e01dca41002 1446 * that byte of sequence-space from the packet */
donatien 0:8e01dca41002 1447 TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
donatien 0:8e01dca41002 1448 }
donatien 0:8e01dca41002 1449 /* Adjust length of segment to fit in the window. */
donatien 0:8e01dca41002 1450 next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
donatien 0:8e01dca41002 1451 pbuf_realloc(next->next->p, next->next->len);
donatien 0:8e01dca41002 1452 tcplen = TCP_TCPLEN(next->next);
donatien 0:8e01dca41002 1453 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
donatien 0:8e01dca41002 1454 (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
donatien 0:8e01dca41002 1455 }
donatien 0:8e01dca41002 1456 }
donatien 0:8e01dca41002 1457 break;
donatien 0:8e01dca41002 1458 }
donatien 0:8e01dca41002 1459 }
donatien 0:8e01dca41002 1460 prev = next;
donatien 0:8e01dca41002 1461 }
donatien 0:8e01dca41002 1462 }
donatien 0:8e01dca41002 1463 #endif /* TCP_QUEUE_OOSEQ */
donatien 0:8e01dca41002 1464
donatien 0:8e01dca41002 1465 }
donatien 0:8e01dca41002 1466 } else {
donatien 0:8e01dca41002 1467 /* The incoming segment is not withing the window. */
donatien 0:8e01dca41002 1468 tcp_send_empty_ack(pcb);
donatien 0:8e01dca41002 1469 }
donatien 0:8e01dca41002 1470 } else {
donatien 0:8e01dca41002 1471 /* Segments with length 0 is taken care of here. Segments that
donatien 0:8e01dca41002 1472 fall out of the window are ACKed. */
donatien 0:8e01dca41002 1473 /*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) ||
donatien 0:8e01dca41002 1474 TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
donatien 0:8e01dca41002 1475 if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
donatien 0:8e01dca41002 1476 tcp_ack_now(pcb);
donatien 0:8e01dca41002 1477 }
donatien 0:8e01dca41002 1478 }
donatien 0:8e01dca41002 1479 }
donatien 0:8e01dca41002 1480
donatien 0:8e01dca41002 1481 /**
donatien 0:8e01dca41002 1482 * Parses the options contained in the incoming segment.
donatien 0:8e01dca41002 1483 *
donatien 0:8e01dca41002 1484 * Called from tcp_listen_input() and tcp_process().
donatien 0:8e01dca41002 1485 * Currently, only the MSS option is supported!
donatien 0:8e01dca41002 1486 *
donatien 0:8e01dca41002 1487 * @param pcb the tcp_pcb for which a segment arrived
donatien 0:8e01dca41002 1488 */
donatien 0:8e01dca41002 1489 static void
donatien 0:8e01dca41002 1490 tcp_parseopt(struct tcp_pcb *pcb)
donatien 0:8e01dca41002 1491 {
donatien 0:8e01dca41002 1492 u16_t c, max_c;
donatien 0:8e01dca41002 1493 u16_t mss;
donatien 0:8e01dca41002 1494 u8_t *opts, opt;
donatien 0:8e01dca41002 1495 #if LWIP_TCP_TIMESTAMPS
donatien 0:8e01dca41002 1496 u32_t tsval;
donatien 0:8e01dca41002 1497 #endif
donatien 0:8e01dca41002 1498
donatien 0:8e01dca41002 1499 opts = (u8_t *)tcphdr + TCP_HLEN;
donatien 0:8e01dca41002 1500
donatien 0:8e01dca41002 1501 /* Parse the TCP MSS option, if present. */
donatien 0:8e01dca41002 1502 if(TCPH_HDRLEN(tcphdr) > 0x5) {
donatien 0:8e01dca41002 1503 max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
donatien 0:8e01dca41002 1504 for (c = 0; c < max_c; ) {
donatien 0:8e01dca41002 1505 opt = opts[c];
donatien 0:8e01dca41002 1506 switch (opt) {
donatien 0:8e01dca41002 1507 case 0x00:
donatien 0:8e01dca41002 1508 /* End of options. */
donatien 0:8e01dca41002 1509 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
donatien 0:8e01dca41002 1510 return;
donatien 0:8e01dca41002 1511 case 0x01:
donatien 0:8e01dca41002 1512 /* NOP option. */
donatien 0:8e01dca41002 1513 ++c;
donatien 0:8e01dca41002 1514 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
donatien 0:8e01dca41002 1515 break;
donatien 0:8e01dca41002 1516 case 0x02:
donatien 0:8e01dca41002 1517 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
donatien 0:8e01dca41002 1518 if (opts[c + 1] != 0x04 || c + 0x04 > max_c) {
donatien 0:8e01dca41002 1519 /* Bad length */
donatien 0:8e01dca41002 1520 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
donatien 0:8e01dca41002 1521 return;
donatien 0:8e01dca41002 1522 }
donatien 0:8e01dca41002 1523 /* An MSS option with the right option length. */
donatien 0:8e01dca41002 1524 mss = (opts[c + 2] << 8) | opts[c + 3];
donatien 0:8e01dca41002 1525 /* Limit the mss to the configured TCP_MSS and prevent division by zero */
donatien 0:8e01dca41002 1526 pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss;
donatien 0:8e01dca41002 1527 /* Advance to next option */
donatien 0:8e01dca41002 1528 c += 0x04;
donatien 0:8e01dca41002 1529 break;
donatien 0:8e01dca41002 1530 #if LWIP_TCP_TIMESTAMPS
donatien 0:8e01dca41002 1531 case 0x08:
donatien 0:8e01dca41002 1532 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
donatien 0:8e01dca41002 1533 if (opts[c + 1] != 0x0A || c + 0x0A > max_c) {
donatien 0:8e01dca41002 1534 /* Bad length */
donatien 0:8e01dca41002 1535 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
donatien 0:8e01dca41002 1536 return;
donatien 0:8e01dca41002 1537 }
donatien 0:8e01dca41002 1538 /* TCP timestamp option with valid length */
donatien 0:8e01dca41002 1539 tsval = (opts[c+2]) | (opts[c+3] << 8) |
donatien 0:8e01dca41002 1540 (opts[c+4] << 16) | (opts[c+5] << 24);
donatien 0:8e01dca41002 1541 if (flags & TCP_SYN) {
donatien 0:8e01dca41002 1542 pcb->ts_recent = ntohl(tsval);
donatien 0:8e01dca41002 1543 pcb->flags |= TF_TIMESTAMP;
donatien 0:8e01dca41002 1544 } else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
donatien 0:8e01dca41002 1545 pcb->ts_recent = ntohl(tsval);
donatien 0:8e01dca41002 1546 }
donatien 0:8e01dca41002 1547 /* Advance to next option */
donatien 0:8e01dca41002 1548 c += 0x0A;
donatien 0:8e01dca41002 1549 break;
donatien 0:8e01dca41002 1550 #endif
donatien 0:8e01dca41002 1551 default:
donatien 0:8e01dca41002 1552 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
donatien 0:8e01dca41002 1553 if (opts[c + 1] == 0) {
donatien 0:8e01dca41002 1554 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
donatien 0:8e01dca41002 1555 /* If the length field is zero, the options are malformed
donatien 0:8e01dca41002 1556 and we don't process them further. */
donatien 0:8e01dca41002 1557 return;
donatien 0:8e01dca41002 1558 }
donatien 0:8e01dca41002 1559 /* All other options have a length field, so that we easily
donatien 0:8e01dca41002 1560 can skip past them. */
donatien 0:8e01dca41002 1561 c += opts[c + 1];
donatien 0:8e01dca41002 1562 }
donatien 0:8e01dca41002 1563 }
donatien 0:8e01dca41002 1564 }
donatien 0:8e01dca41002 1565 }
donatien 0:8e01dca41002 1566
donatien 0:8e01dca41002 1567 #endif /* LWIP_TCP */