CK Sin / Mbed 2 deprecated Ethernetwebsocket

Ethernetwebsoc

Dependencies:   C12832_lcd LM75B WebSocketClient mbed-rtos mbed Socket lwip-eth lwip-sys lwip

EthernetInterface/lwip/core/tcp_in.c@0:0ed2a7c7190c, 2013-05-31 (annotated)

Committer:
GordonSin
Date:
Fri May 31 04:09:54 2013 +0000
Revision:
0:0ed2a7c7190c
31/5/2013;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
GordonSin 0:0ed2a7c7190c 1 /**
GordonSin 0:0ed2a7c7190c 2 * @file
GordonSin 0:0ed2a7c7190c 3 * Transmission Control Protocol, incoming traffic
GordonSin 0:0ed2a7c7190c 4 *
GordonSin 0:0ed2a7c7190c 5 * The input processing functions of the TCP layer.
GordonSin 0:0ed2a7c7190c 6 *
GordonSin 0:0ed2a7c7190c 7 * These functions are generally called in the order (ip_input() ->)
GordonSin 0:0ed2a7c7190c 8 * tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
GordonSin 0:0ed2a7c7190c 9 *
GordonSin 0:0ed2a7c7190c 10 */
GordonSin 0:0ed2a7c7190c 11
GordonSin 0:0ed2a7c7190c 12 /*
GordonSin 0:0ed2a7c7190c 13 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
GordonSin 0:0ed2a7c7190c 14 * All rights reserved.
GordonSin 0:0ed2a7c7190c 15 *
GordonSin 0:0ed2a7c7190c 16 * Redistribution and use in source and binary forms, with or without modification,
GordonSin 0:0ed2a7c7190c 17 * are permitted provided that the following conditions are met:
GordonSin 0:0ed2a7c7190c 18 *
GordonSin 0:0ed2a7c7190c 19 * 1. Redistributions of source code must retain the above copyright notice,
GordonSin 0:0ed2a7c7190c 20 * this list of conditions and the following disclaimer.
GordonSin 0:0ed2a7c7190c 21 * 2. Redistributions in binary form must reproduce the above copyright notice,
GordonSin 0:0ed2a7c7190c 22 * this list of conditions and the following disclaimer in the documentation
GordonSin 0:0ed2a7c7190c 23 * and/or other materials provided with the distribution.
GordonSin 0:0ed2a7c7190c 24 * 3. The name of the author may not be used to endorse or promote products
GordonSin 0:0ed2a7c7190c 25 * derived from this software without specific prior written permission.
GordonSin 0:0ed2a7c7190c 26 *
GordonSin 0:0ed2a7c7190c 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
GordonSin 0:0ed2a7c7190c 28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
GordonSin 0:0ed2a7c7190c 29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
GordonSin 0:0ed2a7c7190c 30 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
GordonSin 0:0ed2a7c7190c 31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
GordonSin 0:0ed2a7c7190c 32 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
GordonSin 0:0ed2a7c7190c 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
GordonSin 0:0ed2a7c7190c 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
GordonSin 0:0ed2a7c7190c 35 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
GordonSin 0:0ed2a7c7190c 36 * OF SUCH DAMAGE.
GordonSin 0:0ed2a7c7190c 37 *
GordonSin 0:0ed2a7c7190c 38 * This file is part of the lwIP TCP/IP stack.
GordonSin 0:0ed2a7c7190c 39 *
GordonSin 0:0ed2a7c7190c 40 * Author: Adam Dunkels <adam@sics.se>
GordonSin 0:0ed2a7c7190c 41 *
GordonSin 0:0ed2a7c7190c 42 */
GordonSin 0:0ed2a7c7190c 43
GordonSin 0:0ed2a7c7190c 44 #include "lwip/opt.h"
GordonSin 0:0ed2a7c7190c 45
GordonSin 0:0ed2a7c7190c 46 #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
GordonSin 0:0ed2a7c7190c 47
GordonSin 0:0ed2a7c7190c 48 #include "lwip/tcp_impl.h"
GordonSin 0:0ed2a7c7190c 49 #include "lwip/def.h"
GordonSin 0:0ed2a7c7190c 50 #include "lwip/ip_addr.h"
GordonSin 0:0ed2a7c7190c 51 #include "lwip/netif.h"
GordonSin 0:0ed2a7c7190c 52 #include "lwip/mem.h"
GordonSin 0:0ed2a7c7190c 53 #include "lwip/memp.h"
GordonSin 0:0ed2a7c7190c 54 #include "lwip/inet_chksum.h"
GordonSin 0:0ed2a7c7190c 55 #include "lwip/stats.h"
GordonSin 0:0ed2a7c7190c 56 #include "lwip/snmp.h"
GordonSin 0:0ed2a7c7190c 57 #include "arch/perf.h"
GordonSin 0:0ed2a7c7190c 58
GordonSin 0:0ed2a7c7190c 59 /* These variables are global to all functions involved in the input
GordonSin 0:0ed2a7c7190c 60 processing of TCP segments. They are set by the tcp_input()
GordonSin 0:0ed2a7c7190c 61 function. */
GordonSin 0:0ed2a7c7190c 62 static struct tcp_seg inseg;
GordonSin 0:0ed2a7c7190c 63 static struct tcp_hdr *tcphdr;
GordonSin 0:0ed2a7c7190c 64 static struct ip_hdr *iphdr;
GordonSin 0:0ed2a7c7190c 65 static u32_t seqno, ackno;
GordonSin 0:0ed2a7c7190c 66 static u8_t flags;
GordonSin 0:0ed2a7c7190c 67 static u16_t tcplen;
GordonSin 0:0ed2a7c7190c 68
GordonSin 0:0ed2a7c7190c 69 static u8_t recv_flags;
GordonSin 0:0ed2a7c7190c 70 static struct pbuf *recv_data;
GordonSin 0:0ed2a7c7190c 71
GordonSin 0:0ed2a7c7190c 72 struct tcp_pcb *tcp_input_pcb;
GordonSin 0:0ed2a7c7190c 73
GordonSin 0:0ed2a7c7190c 74 /* Forward declarations. */
GordonSin 0:0ed2a7c7190c 75 static err_t tcp_process(struct tcp_pcb *pcb);
GordonSin 0:0ed2a7c7190c 76 static void tcp_receive(struct tcp_pcb *pcb);
GordonSin 0:0ed2a7c7190c 77 static void tcp_parseopt(struct tcp_pcb *pcb);
GordonSin 0:0ed2a7c7190c 78
GordonSin 0:0ed2a7c7190c 79 static err_t tcp_listen_input(struct tcp_pcb_listen *pcb);
GordonSin 0:0ed2a7c7190c 80 static err_t tcp_timewait_input(struct tcp_pcb *pcb);
GordonSin 0:0ed2a7c7190c 81
GordonSin 0:0ed2a7c7190c 82 /**
GordonSin 0:0ed2a7c7190c 83 * The initial input processing of TCP. It verifies the TCP header, demultiplexes
GordonSin 0:0ed2a7c7190c 84 * the segment between the PCBs and passes it on to tcp_process(), which implements
GordonSin 0:0ed2a7c7190c 85 * the TCP finite state machine. This function is called by the IP layer (in
GordonSin 0:0ed2a7c7190c 86 * ip_input()).
GordonSin 0:0ed2a7c7190c 87 *
GordonSin 0:0ed2a7c7190c 88 * @param p received TCP segment to process (p->payload pointing to the IP header)
GordonSin 0:0ed2a7c7190c 89 * @param inp network interface on which this segment was received
GordonSin 0:0ed2a7c7190c 90 */
GordonSin 0:0ed2a7c7190c 91 void
GordonSin 0:0ed2a7c7190c 92 tcp_input(struct pbuf *p, struct netif *inp)
GordonSin 0:0ed2a7c7190c 93 {
GordonSin 0:0ed2a7c7190c 94 struct tcp_pcb *pcb, *prev;
GordonSin 0:0ed2a7c7190c 95 struct tcp_pcb_listen *lpcb;
GordonSin 0:0ed2a7c7190c 96 #if SO_REUSE
GordonSin 0:0ed2a7c7190c 97 struct tcp_pcb *lpcb_prev = NULL;
GordonSin 0:0ed2a7c7190c 98 struct tcp_pcb_listen *lpcb_any = NULL;
GordonSin 0:0ed2a7c7190c 99 #endif /* SO_REUSE */
GordonSin 0:0ed2a7c7190c 100 u8_t hdrlen;
GordonSin 0:0ed2a7c7190c 101 err_t err;
GordonSin 0:0ed2a7c7190c 102
GordonSin 0:0ed2a7c7190c 103 PERF_START;
GordonSin 0:0ed2a7c7190c 104
GordonSin 0:0ed2a7c7190c 105 TCP_STATS_INC(tcp.recv);
GordonSin 0:0ed2a7c7190c 106 snmp_inc_tcpinsegs();
GordonSin 0:0ed2a7c7190c 107
GordonSin 0:0ed2a7c7190c 108 iphdr = (struct ip_hdr *)p->payload;
GordonSin 0:0ed2a7c7190c 109 tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
GordonSin 0:0ed2a7c7190c 110
GordonSin 0:0ed2a7c7190c 111 #if TCP_INPUT_DEBUG
GordonSin 0:0ed2a7c7190c 112 tcp_debug_print(tcphdr);
GordonSin 0:0ed2a7c7190c 113 #endif
GordonSin 0:0ed2a7c7190c 114
GordonSin 0:0ed2a7c7190c 115 /* remove header from payload */
GordonSin 0:0ed2a7c7190c 116 if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) {
GordonSin 0:0ed2a7c7190c 117 /* drop short packets */
GordonSin 0:0ed2a7c7190c 118 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
GordonSin 0:0ed2a7c7190c 119 TCP_STATS_INC(tcp.lenerr);
GordonSin 0:0ed2a7c7190c 120 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 121 snmp_inc_tcpinerrs();
GordonSin 0:0ed2a7c7190c 122 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 123 return;
GordonSin 0:0ed2a7c7190c 124 }
GordonSin 0:0ed2a7c7190c 125
GordonSin 0:0ed2a7c7190c 126 /* Don't even process incoming broadcasts/multicasts. */
GordonSin 0:0ed2a7c7190c 127 if (ip_addr_isbroadcast(&current_iphdr_dest, inp) ||
GordonSin 0:0ed2a7c7190c 128 ip_addr_ismulticast(&current_iphdr_dest)) {
GordonSin 0:0ed2a7c7190c 129 TCP_STATS_INC(tcp.proterr);
GordonSin 0:0ed2a7c7190c 130 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 131 snmp_inc_tcpinerrs();
GordonSin 0:0ed2a7c7190c 132 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 133 return;
GordonSin 0:0ed2a7c7190c 134 }
GordonSin 0:0ed2a7c7190c 135
GordonSin 0:0ed2a7c7190c 136 #if CHECKSUM_CHECK_TCP
GordonSin 0:0ed2a7c7190c 137 /* Verify TCP checksum. */
GordonSin 0:0ed2a7c7190c 138 if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
GordonSin 0:0ed2a7c7190c 139 IP_PROTO_TCP, p->tot_len) != 0) {
GordonSin 0:0ed2a7c7190c 140 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
GordonSin 0:0ed2a7c7190c 141 inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
GordonSin 0:0ed2a7c7190c 142 IP_PROTO_TCP, p->tot_len)));
GordonSin 0:0ed2a7c7190c 143 #if TCP_DEBUG
GordonSin 0:0ed2a7c7190c 144 tcp_debug_print(tcphdr);
GordonSin 0:0ed2a7c7190c 145 #endif /* TCP_DEBUG */
GordonSin 0:0ed2a7c7190c 146 TCP_STATS_INC(tcp.chkerr);
GordonSin 0:0ed2a7c7190c 147 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 148 snmp_inc_tcpinerrs();
GordonSin 0:0ed2a7c7190c 149 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 150 return;
GordonSin 0:0ed2a7c7190c 151 }
GordonSin 0:0ed2a7c7190c 152 #endif
GordonSin 0:0ed2a7c7190c 153
GordonSin 0:0ed2a7c7190c 154 /* Move the payload pointer in the pbuf so that it points to the
GordonSin 0:0ed2a7c7190c 155 TCP data instead of the TCP header. */
GordonSin 0:0ed2a7c7190c 156 hdrlen = TCPH_HDRLEN(tcphdr);
GordonSin 0:0ed2a7c7190c 157 if(pbuf_header(p, -(hdrlen * 4))){
GordonSin 0:0ed2a7c7190c 158 /* drop short packets */
GordonSin 0:0ed2a7c7190c 159 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
GordonSin 0:0ed2a7c7190c 160 TCP_STATS_INC(tcp.lenerr);
GordonSin 0:0ed2a7c7190c 161 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 162 snmp_inc_tcpinerrs();
GordonSin 0:0ed2a7c7190c 163 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 164 return;
GordonSin 0:0ed2a7c7190c 165 }
GordonSin 0:0ed2a7c7190c 166
GordonSin 0:0ed2a7c7190c 167 /* Convert fields in TCP header to host byte order. */
GordonSin 0:0ed2a7c7190c 168 tcphdr->src = ntohs(tcphdr->src);
GordonSin 0:0ed2a7c7190c 169 tcphdr->dest = ntohs(tcphdr->dest);
GordonSin 0:0ed2a7c7190c 170 seqno = tcphdr->seqno = ntohl(tcphdr->seqno);
GordonSin 0:0ed2a7c7190c 171 ackno = tcphdr->ackno = ntohl(tcphdr->ackno);
GordonSin 0:0ed2a7c7190c 172 tcphdr->wnd = ntohs(tcphdr->wnd);
GordonSin 0:0ed2a7c7190c 173
GordonSin 0:0ed2a7c7190c 174 flags = TCPH_FLAGS(tcphdr);
GordonSin 0:0ed2a7c7190c 175 tcplen = p->tot_len + ((flags & (TCP_FIN | TCP_SYN)) ? 1 : 0);
GordonSin 0:0ed2a7c7190c 176
GordonSin 0:0ed2a7c7190c 177 /* Demultiplex an incoming segment. First, we check if it is destined
GordonSin 0:0ed2a7c7190c 178 for an active connection. */
GordonSin 0:0ed2a7c7190c 179 prev = NULL;
GordonSin 0:0ed2a7c7190c 180
GordonSin 0:0ed2a7c7190c 181
GordonSin 0:0ed2a7c7190c 182 for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {
GordonSin 0:0ed2a7c7190c 183 LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
GordonSin 0:0ed2a7c7190c 184 LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
GordonSin 0:0ed2a7c7190c 185 LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
GordonSin 0:0ed2a7c7190c 186 if (pcb->remote_port == tcphdr->src &&
GordonSin 0:0ed2a7c7190c 187 pcb->local_port == tcphdr->dest &&
GordonSin 0:0ed2a7c7190c 188 ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
GordonSin 0:0ed2a7c7190c 189 ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
GordonSin 0:0ed2a7c7190c 190
GordonSin 0:0ed2a7c7190c 191 /* Move this PCB to the front of the list so that subsequent
GordonSin 0:0ed2a7c7190c 192 lookups will be faster (we exploit locality in TCP segment
GordonSin 0:0ed2a7c7190c 193 arrivals). */
GordonSin 0:0ed2a7c7190c 194 LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
GordonSin 0:0ed2a7c7190c 195 if (prev != NULL) {
GordonSin 0:0ed2a7c7190c 196 prev->next = pcb->next;
GordonSin 0:0ed2a7c7190c 197 pcb->next = tcp_active_pcbs;
GordonSin 0:0ed2a7c7190c 198 tcp_active_pcbs = pcb;
GordonSin 0:0ed2a7c7190c 199 }
GordonSin 0:0ed2a7c7190c 200 LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
GordonSin 0:0ed2a7c7190c 201 break;
GordonSin 0:0ed2a7c7190c 202 }
GordonSin 0:0ed2a7c7190c 203 prev = pcb;
GordonSin 0:0ed2a7c7190c 204 }
GordonSin 0:0ed2a7c7190c 205
GordonSin 0:0ed2a7c7190c 206 if (pcb == NULL) {
GordonSin 0:0ed2a7c7190c 207 /* If it did not go to an active connection, we check the connections
GordonSin 0:0ed2a7c7190c 208 in the TIME-WAIT state. */
GordonSin 0:0ed2a7c7190c 209 for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {
GordonSin 0:0ed2a7c7190c 210 LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
GordonSin 0:0ed2a7c7190c 211 if (pcb->remote_port == tcphdr->src &&
GordonSin 0:0ed2a7c7190c 212 pcb->local_port == tcphdr->dest &&
GordonSin 0:0ed2a7c7190c 213 ip_addr_cmp(&(pcb->remote_ip), &current_iphdr_src) &&
GordonSin 0:0ed2a7c7190c 214 ip_addr_cmp(&(pcb->local_ip), &current_iphdr_dest)) {
GordonSin 0:0ed2a7c7190c 215 /* We don't really care enough to move this PCB to the front
GordonSin 0:0ed2a7c7190c 216 of the list since we are not very likely to receive that
GordonSin 0:0ed2a7c7190c 217 many segments for connections in TIME-WAIT. */
GordonSin 0:0ed2a7c7190c 218 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
GordonSin 0:0ed2a7c7190c 219 tcp_timewait_input(pcb);
GordonSin 0:0ed2a7c7190c 220 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 221 return;
GordonSin 0:0ed2a7c7190c 222 }
GordonSin 0:0ed2a7c7190c 223 }
GordonSin 0:0ed2a7c7190c 224
GordonSin 0:0ed2a7c7190c 225 /* Finally, if we still did not get a match, we check all PCBs that
GordonSin 0:0ed2a7c7190c 226 are LISTENing for incoming connections. */
GordonSin 0:0ed2a7c7190c 227 prev = NULL;
GordonSin 0:0ed2a7c7190c 228 for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {
GordonSin 0:0ed2a7c7190c 229 if (lpcb->local_port == tcphdr->dest) {
GordonSin 0:0ed2a7c7190c 230 #if SO_REUSE
GordonSin 0:0ed2a7c7190c 231 if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest)) {
GordonSin 0:0ed2a7c7190c 232 /* found an exact match */
GordonSin 0:0ed2a7c7190c 233 break;
GordonSin 0:0ed2a7c7190c 234 } else if(ip_addr_isany(&(lpcb->local_ip))) {
GordonSin 0:0ed2a7c7190c 235 /* found an ANY-match */
GordonSin 0:0ed2a7c7190c 236 lpcb_any = lpcb;
GordonSin 0:0ed2a7c7190c 237 lpcb_prev = prev;
GordonSin 0:0ed2a7c7190c 238 }
GordonSin 0:0ed2a7c7190c 239 #else /* SO_REUSE */
GordonSin 0:0ed2a7c7190c 240 if (ip_addr_cmp(&(lpcb->local_ip), &current_iphdr_dest) ||
GordonSin 0:0ed2a7c7190c 241 ip_addr_isany(&(lpcb->local_ip))) {
GordonSin 0:0ed2a7c7190c 242 /* found a match */
GordonSin 0:0ed2a7c7190c 243 break;
GordonSin 0:0ed2a7c7190c 244 }
GordonSin 0:0ed2a7c7190c 245 #endif /* SO_REUSE */
GordonSin 0:0ed2a7c7190c 246 }
GordonSin 0:0ed2a7c7190c 247 prev = (struct tcp_pcb *)lpcb;
GordonSin 0:0ed2a7c7190c 248 }
GordonSin 0:0ed2a7c7190c 249 #if SO_REUSE
GordonSin 0:0ed2a7c7190c 250 /* first try specific local IP */
GordonSin 0:0ed2a7c7190c 251 if (lpcb == NULL) {
GordonSin 0:0ed2a7c7190c 252 /* only pass to ANY if no specific local IP has been found */
GordonSin 0:0ed2a7c7190c 253 lpcb = lpcb_any;
GordonSin 0:0ed2a7c7190c 254 prev = lpcb_prev;
GordonSin 0:0ed2a7c7190c 255 }
GordonSin 0:0ed2a7c7190c 256 #endif /* SO_REUSE */
GordonSin 0:0ed2a7c7190c 257 if (lpcb != NULL) {
GordonSin 0:0ed2a7c7190c 258 /* Move this PCB to the front of the list so that subsequent
GordonSin 0:0ed2a7c7190c 259 lookups will be faster (we exploit locality in TCP segment
GordonSin 0:0ed2a7c7190c 260 arrivals). */
GordonSin 0:0ed2a7c7190c 261 if (prev != NULL) {
GordonSin 0:0ed2a7c7190c 262 ((struct tcp_pcb_listen *)prev)->next = lpcb->next;
GordonSin 0:0ed2a7c7190c 263 /* our successor is the remainder of the listening list */
GordonSin 0:0ed2a7c7190c 264 lpcb->next = tcp_listen_pcbs.listen_pcbs;
GordonSin 0:0ed2a7c7190c 265 /* put this listening pcb at the head of the listening list */
GordonSin 0:0ed2a7c7190c 266 tcp_listen_pcbs.listen_pcbs = lpcb;
GordonSin 0:0ed2a7c7190c 267 }
GordonSin 0:0ed2a7c7190c 268
GordonSin 0:0ed2a7c7190c 269 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
GordonSin 0:0ed2a7c7190c 270 tcp_listen_input(lpcb);
GordonSin 0:0ed2a7c7190c 271 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 272 return;
GordonSin 0:0ed2a7c7190c 273 }
GordonSin 0:0ed2a7c7190c 274 }
GordonSin 0:0ed2a7c7190c 275
GordonSin 0:0ed2a7c7190c 276 #if TCP_INPUT_DEBUG
GordonSin 0:0ed2a7c7190c 277 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
GordonSin 0:0ed2a7c7190c 278 tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
GordonSin 0:0ed2a7c7190c 279 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
GordonSin 0:0ed2a7c7190c 280 #endif /* TCP_INPUT_DEBUG */
GordonSin 0:0ed2a7c7190c 281
GordonSin 0:0ed2a7c7190c 282
GordonSin 0:0ed2a7c7190c 283 if (pcb != NULL) {
GordonSin 0:0ed2a7c7190c 284 /* The incoming segment belongs to a connection. */
GordonSin 0:0ed2a7c7190c 285 #if TCP_INPUT_DEBUG
GordonSin 0:0ed2a7c7190c 286 #if TCP_DEBUG
GordonSin 0:0ed2a7c7190c 287 tcp_debug_print_state(pcb->state);
GordonSin 0:0ed2a7c7190c 288 #endif /* TCP_DEBUG */
GordonSin 0:0ed2a7c7190c 289 #endif /* TCP_INPUT_DEBUG */
GordonSin 0:0ed2a7c7190c 290
GordonSin 0:0ed2a7c7190c 291 /* Set up a tcp_seg structure. */
GordonSin 0:0ed2a7c7190c 292 inseg.next = NULL;
GordonSin 0:0ed2a7c7190c 293 inseg.len = p->tot_len;
GordonSin 0:0ed2a7c7190c 294 inseg.p = p;
GordonSin 0:0ed2a7c7190c 295 inseg.tcphdr = tcphdr;
GordonSin 0:0ed2a7c7190c 296
GordonSin 0:0ed2a7c7190c 297 recv_data = NULL;
GordonSin 0:0ed2a7c7190c 298 recv_flags = 0;
GordonSin 0:0ed2a7c7190c 299
GordonSin 0:0ed2a7c7190c 300 /* If there is data which was previously "refused" by upper layer */
GordonSin 0:0ed2a7c7190c 301 if (pcb->refused_data != NULL) {
GordonSin 0:0ed2a7c7190c 302 /* Notify again application with data previously received. */
GordonSin 0:0ed2a7c7190c 303 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
GordonSin 0:0ed2a7c7190c 304 TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);
GordonSin 0:0ed2a7c7190c 305 if (err == ERR_OK) {
GordonSin 0:0ed2a7c7190c 306 pcb->refused_data = NULL;
GordonSin 0:0ed2a7c7190c 307 } else if ((err == ERR_ABRT) || (tcplen > 0)) {
GordonSin 0:0ed2a7c7190c 308 /* if err == ERR_ABRT, 'pcb' is already deallocated */
GordonSin 0:0ed2a7c7190c 309 /* Drop incoming packets because pcb is "full" (only if the incoming
GordonSin 0:0ed2a7c7190c 310 segment contains data). */
GordonSin 0:0ed2a7c7190c 311 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
GordonSin 0:0ed2a7c7190c 312 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 313 snmp_inc_tcpinerrs();
GordonSin 0:0ed2a7c7190c 314 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 315 return;
GordonSin 0:0ed2a7c7190c 316 }
GordonSin 0:0ed2a7c7190c 317 }
GordonSin 0:0ed2a7c7190c 318 tcp_input_pcb = pcb;
GordonSin 0:0ed2a7c7190c 319 err = tcp_process(pcb);
GordonSin 0:0ed2a7c7190c 320 /* A return value of ERR_ABRT means that tcp_abort() was called
GordonSin 0:0ed2a7c7190c 321 and that the pcb has been freed. If so, we don't do anything. */
GordonSin 0:0ed2a7c7190c 322 if (err != ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 323 if (recv_flags & TF_RESET) {
GordonSin 0:0ed2a7c7190c 324 /* TF_RESET means that the connection was reset by the other
GordonSin 0:0ed2a7c7190c 325 end. We then call the error callback to inform the
GordonSin 0:0ed2a7c7190c 326 application that the connection is dead before we
GordonSin 0:0ed2a7c7190c 327 deallocate the PCB. */
GordonSin 0:0ed2a7c7190c 328 TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
GordonSin 0:0ed2a7c7190c 329 tcp_pcb_remove(&tcp_active_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 330 memp_free(MEMP_TCP_PCB, pcb);
GordonSin 0:0ed2a7c7190c 331 } else if (recv_flags & TF_CLOSED) {
GordonSin 0:0ed2a7c7190c 332 /* The connection has been closed and we will deallocate the
GordonSin 0:0ed2a7c7190c 333 PCB. */
GordonSin 0:0ed2a7c7190c 334 tcp_pcb_remove(&tcp_active_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 335 memp_free(MEMP_TCP_PCB, pcb);
GordonSin 0:0ed2a7c7190c 336 } else {
GordonSin 0:0ed2a7c7190c 337 err = ERR_OK;
GordonSin 0:0ed2a7c7190c 338 /* If the application has registered a "sent" function to be
GordonSin 0:0ed2a7c7190c 339 called when new send buffer space is available, we call it
GordonSin 0:0ed2a7c7190c 340 now. */
GordonSin 0:0ed2a7c7190c 341 if (pcb->acked > 0) {
GordonSin 0:0ed2a7c7190c 342 TCP_EVENT_SENT(pcb, pcb->acked, err);
GordonSin 0:0ed2a7c7190c 343 if (err == ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 344 goto aborted;
GordonSin 0:0ed2a7c7190c 345 }
GordonSin 0:0ed2a7c7190c 346 }
GordonSin 0:0ed2a7c7190c 347
GordonSin 0:0ed2a7c7190c 348 if (recv_data != NULL) {
GordonSin 0:0ed2a7c7190c 349 LWIP_ASSERT("pcb->refused_data == NULL", pcb->refused_data == NULL);
GordonSin 0:0ed2a7c7190c 350 if (pcb->flags & TF_RXCLOSED) {
GordonSin 0:0ed2a7c7190c 351 /* received data although already closed -> abort (send RST) to
GordonSin 0:0ed2a7c7190c 352 notify the remote host that not all data has been processed */
GordonSin 0:0ed2a7c7190c 353 pbuf_free(recv_data);
GordonSin 0:0ed2a7c7190c 354 tcp_abort(pcb);
GordonSin 0:0ed2a7c7190c 355 goto aborted;
GordonSin 0:0ed2a7c7190c 356 }
GordonSin 0:0ed2a7c7190c 357 if (flags & TCP_PSH) {
GordonSin 0:0ed2a7c7190c 358 recv_data->flags |= PBUF_FLAG_PUSH;
GordonSin 0:0ed2a7c7190c 359 }
GordonSin 0:0ed2a7c7190c 360
GordonSin 0:0ed2a7c7190c 361 /* Notify application that data has been received. */
GordonSin 0:0ed2a7c7190c 362 TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
GordonSin 0:0ed2a7c7190c 363 if (err == ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 364 goto aborted;
GordonSin 0:0ed2a7c7190c 365 }
GordonSin 0:0ed2a7c7190c 366
GordonSin 0:0ed2a7c7190c 367 /* If the upper layer can't receive this data, store it */
GordonSin 0:0ed2a7c7190c 368 if (err != ERR_OK) {
GordonSin 0:0ed2a7c7190c 369 pcb->refused_data = recv_data;
GordonSin 0:0ed2a7c7190c 370 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
GordonSin 0:0ed2a7c7190c 371 }
GordonSin 0:0ed2a7c7190c 372 }
GordonSin 0:0ed2a7c7190c 373
GordonSin 0:0ed2a7c7190c 374 /* If a FIN segment was received, we call the callback
GordonSin 0:0ed2a7c7190c 375 function with a NULL buffer to indicate EOF. */
GordonSin 0:0ed2a7c7190c 376 if (recv_flags & TF_GOT_FIN) {
GordonSin 0:0ed2a7c7190c 377 /* correct rcv_wnd as the application won't call tcp_recved()
GordonSin 0:0ed2a7c7190c 378 for the FIN's seqno */
GordonSin 0:0ed2a7c7190c 379 if (pcb->rcv_wnd != TCP_WND) {
GordonSin 0:0ed2a7c7190c 380 pcb->rcv_wnd++;
GordonSin 0:0ed2a7c7190c 381 }
GordonSin 0:0ed2a7c7190c 382 TCP_EVENT_CLOSED(pcb, err);
GordonSin 0:0ed2a7c7190c 383 if (err == ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 384 goto aborted;
GordonSin 0:0ed2a7c7190c 385 }
GordonSin 0:0ed2a7c7190c 386 }
GordonSin 0:0ed2a7c7190c 387
GordonSin 0:0ed2a7c7190c 388 tcp_input_pcb = NULL;
GordonSin 0:0ed2a7c7190c 389 /* Try to send something out. */
GordonSin 0:0ed2a7c7190c 390 tcp_output(pcb);
GordonSin 0:0ed2a7c7190c 391 #if TCP_INPUT_DEBUG
GordonSin 0:0ed2a7c7190c 392 #if TCP_DEBUG
GordonSin 0:0ed2a7c7190c 393 tcp_debug_print_state(pcb->state);
GordonSin 0:0ed2a7c7190c 394 #endif /* TCP_DEBUG */
GordonSin 0:0ed2a7c7190c 395 #endif /* TCP_INPUT_DEBUG */
GordonSin 0:0ed2a7c7190c 396 }
GordonSin 0:0ed2a7c7190c 397 }
GordonSin 0:0ed2a7c7190c 398 /* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
GordonSin 0:0ed2a7c7190c 399 Below this line, 'pcb' may not be dereferenced! */
GordonSin 0:0ed2a7c7190c 400 aborted:
GordonSin 0:0ed2a7c7190c 401 tcp_input_pcb = NULL;
GordonSin 0:0ed2a7c7190c 402 recv_data = NULL;
GordonSin 0:0ed2a7c7190c 403
GordonSin 0:0ed2a7c7190c 404 /* give up our reference to inseg.p */
GordonSin 0:0ed2a7c7190c 405 if (inseg.p != NULL)
GordonSin 0:0ed2a7c7190c 406 {
GordonSin 0:0ed2a7c7190c 407 pbuf_free(inseg.p);
GordonSin 0:0ed2a7c7190c 408 inseg.p = NULL;
GordonSin 0:0ed2a7c7190c 409 }
GordonSin 0:0ed2a7c7190c 410 } else {
GordonSin 0:0ed2a7c7190c 411
GordonSin 0:0ed2a7c7190c 412 /* If no matching PCB was found, send a TCP RST (reset) to the
GordonSin 0:0ed2a7c7190c 413 sender. */
GordonSin 0:0ed2a7c7190c 414 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
GordonSin 0:0ed2a7c7190c 415 if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
GordonSin 0:0ed2a7c7190c 416 TCP_STATS_INC(tcp.proterr);
GordonSin 0:0ed2a7c7190c 417 TCP_STATS_INC(tcp.drop);
GordonSin 0:0ed2a7c7190c 418 tcp_rst(ackno, seqno + tcplen,
GordonSin 0:0ed2a7c7190c 419 ip_current_dest_addr(), ip_current_src_addr(),
GordonSin 0:0ed2a7c7190c 420 tcphdr->dest, tcphdr->src);
GordonSin 0:0ed2a7c7190c 421 }
GordonSin 0:0ed2a7c7190c 422 pbuf_free(p);
GordonSin 0:0ed2a7c7190c 423 }
GordonSin 0:0ed2a7c7190c 424
GordonSin 0:0ed2a7c7190c 425 LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
GordonSin 0:0ed2a7c7190c 426 PERF_STOP("tcp_input");
GordonSin 0:0ed2a7c7190c 427 }
GordonSin 0:0ed2a7c7190c 428
GordonSin 0:0ed2a7c7190c 429 /**
GordonSin 0:0ed2a7c7190c 430 * Called by tcp_input() when a segment arrives for a listening
GordonSin 0:0ed2a7c7190c 431 * connection (from tcp_input()).
GordonSin 0:0ed2a7c7190c 432 *
GordonSin 0:0ed2a7c7190c 433 * @param pcb the tcp_pcb_listen for which a segment arrived
GordonSin 0:0ed2a7c7190c 434 * @return ERR_OK if the segment was processed
GordonSin 0:0ed2a7c7190c 435 * another err_t on error
GordonSin 0:0ed2a7c7190c 436 *
GordonSin 0:0ed2a7c7190c 437 * @note the return value is not (yet?) used in tcp_input()
GordonSin 0:0ed2a7c7190c 438 * @note the segment which arrived is saved in global variables, therefore only the pcb
GordonSin 0:0ed2a7c7190c 439 * involved is passed as a parameter to this function
GordonSin 0:0ed2a7c7190c 440 */
GordonSin 0:0ed2a7c7190c 441 static err_t
GordonSin 0:0ed2a7c7190c 442 tcp_listen_input(struct tcp_pcb_listen *pcb)
GordonSin 0:0ed2a7c7190c 443 {
GordonSin 0:0ed2a7c7190c 444 struct tcp_pcb *npcb;
GordonSin 0:0ed2a7c7190c 445 err_t rc;
GordonSin 0:0ed2a7c7190c 446
GordonSin 0:0ed2a7c7190c 447 /* In the LISTEN state, we check for incoming SYN segments,
GordonSin 0:0ed2a7c7190c 448 creates a new PCB, and responds with a SYN|ACK. */
GordonSin 0:0ed2a7c7190c 449 if (flags & TCP_ACK) {
GordonSin 0:0ed2a7c7190c 450 /* For incoming segments with the ACK flag set, respond with a
GordonSin 0:0ed2a7c7190c 451 RST. */
GordonSin 0:0ed2a7c7190c 452 LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
GordonSin 0:0ed2a7c7190c 453 tcp_rst(ackno + 1, seqno + tcplen,
GordonSin 0:0ed2a7c7190c 454 ip_current_dest_addr(), ip_current_src_addr(),
GordonSin 0:0ed2a7c7190c 455 tcphdr->dest, tcphdr->src);
GordonSin 0:0ed2a7c7190c 456 } else if (flags & TCP_SYN) {
GordonSin 0:0ed2a7c7190c 457 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
GordonSin 0:0ed2a7c7190c 458 #if TCP_LISTEN_BACKLOG
GordonSin 0:0ed2a7c7190c 459 if (pcb->accepts_pending >= pcb->backlog) {
GordonSin 0:0ed2a7c7190c 460 LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
GordonSin 0:0ed2a7c7190c 461 return ERR_ABRT;
GordonSin 0:0ed2a7c7190c 462 }
GordonSin 0:0ed2a7c7190c 463 #endif /* TCP_LISTEN_BACKLOG */
GordonSin 0:0ed2a7c7190c 464 npcb = tcp_alloc(pcb->prio);
GordonSin 0:0ed2a7c7190c 465 /* If a new PCB could not be created (probably due to lack of memory),
GordonSin 0:0ed2a7c7190c 466 we don't do anything, but rely on the sender will retransmit the
GordonSin 0:0ed2a7c7190c 467 SYN at a time when we have more memory available. */
GordonSin 0:0ed2a7c7190c 468 if (npcb == NULL) {
GordonSin 0:0ed2a7c7190c 469 LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
GordonSin 0:0ed2a7c7190c 470 TCP_STATS_INC(tcp.memerr);
GordonSin 0:0ed2a7c7190c 471 return ERR_MEM;
GordonSin 0:0ed2a7c7190c 472 }
GordonSin 0:0ed2a7c7190c 473 #if TCP_LISTEN_BACKLOG
GordonSin 0:0ed2a7c7190c 474 pcb->accepts_pending++;
GordonSin 0:0ed2a7c7190c 475 #endif /* TCP_LISTEN_BACKLOG */
GordonSin 0:0ed2a7c7190c 476 /* Set up the new PCB. */
GordonSin 0:0ed2a7c7190c 477 ip_addr_copy(npcb->local_ip, current_iphdr_dest);
GordonSin 0:0ed2a7c7190c 478 npcb->local_port = pcb->local_port;
GordonSin 0:0ed2a7c7190c 479 ip_addr_copy(npcb->remote_ip, current_iphdr_src);
GordonSin 0:0ed2a7c7190c 480 npcb->remote_port = tcphdr->src;
GordonSin 0:0ed2a7c7190c 481 npcb->state = SYN_RCVD;
GordonSin 0:0ed2a7c7190c 482 npcb->rcv_nxt = seqno + 1;
GordonSin 0:0ed2a7c7190c 483 npcb->rcv_ann_right_edge = npcb->rcv_nxt;
GordonSin 0:0ed2a7c7190c 484 npcb->snd_wnd = tcphdr->wnd;
GordonSin 0:0ed2a7c7190c 485 npcb->ssthresh = npcb->snd_wnd;
GordonSin 0:0ed2a7c7190c 486 npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
GordonSin 0:0ed2a7c7190c 487 npcb->callback_arg = pcb->callback_arg;
GordonSin 0:0ed2a7c7190c 488 #if LWIP_CALLBACK_API
GordonSin 0:0ed2a7c7190c 489 npcb->accept = pcb->accept;
GordonSin 0:0ed2a7c7190c 490 #endif /* LWIP_CALLBACK_API */
GordonSin 0:0ed2a7c7190c 491 /* inherit socket options */
GordonSin 0:0ed2a7c7190c 492 npcb->so_options = pcb->so_options & SOF_INHERITED;
GordonSin 0:0ed2a7c7190c 493 /* Register the new PCB so that we can begin receiving segments
GordonSin 0:0ed2a7c7190c 494 for it. */
GordonSin 0:0ed2a7c7190c 495 TCP_REG(&tcp_active_pcbs, npcb);
GordonSin 0:0ed2a7c7190c 496
GordonSin 0:0ed2a7c7190c 497 /* Parse any options in the SYN. */
GordonSin 0:0ed2a7c7190c 498 tcp_parseopt(npcb);
GordonSin 0:0ed2a7c7190c 499 #if TCP_CALCULATE_EFF_SEND_MSS
GordonSin 0:0ed2a7c7190c 500 npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
GordonSin 0:0ed2a7c7190c 501 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
GordonSin 0:0ed2a7c7190c 502
GordonSin 0:0ed2a7c7190c 503 snmp_inc_tcppassiveopens();
GordonSin 0:0ed2a7c7190c 504
GordonSin 0:0ed2a7c7190c 505 /* Send a SYN|ACK together with the MSS option. */
GordonSin 0:0ed2a7c7190c 506 rc = tcp_enqueue_flags(npcb, TCP_SYN | TCP_ACK);
GordonSin 0:0ed2a7c7190c 507 if (rc != ERR_OK) {
GordonSin 0:0ed2a7c7190c 508 tcp_abandon(npcb, 0);
GordonSin 0:0ed2a7c7190c 509 return rc;
GordonSin 0:0ed2a7c7190c 510 }
GordonSin 0:0ed2a7c7190c 511 return tcp_output(npcb);
GordonSin 0:0ed2a7c7190c 512 }
GordonSin 0:0ed2a7c7190c 513 return ERR_OK;
GordonSin 0:0ed2a7c7190c 514 }
GordonSin 0:0ed2a7c7190c 515
GordonSin 0:0ed2a7c7190c 516 /**
GordonSin 0:0ed2a7c7190c 517 * Called by tcp_input() when a segment arrives for a connection in
GordonSin 0:0ed2a7c7190c 518 * TIME_WAIT.
GordonSin 0:0ed2a7c7190c 519 *
GordonSin 0:0ed2a7c7190c 520 * @param pcb the tcp_pcb for which a segment arrived
GordonSin 0:0ed2a7c7190c 521 *
GordonSin 0:0ed2a7c7190c 522 * @note the segment which arrived is saved in global variables, therefore only the pcb
GordonSin 0:0ed2a7c7190c 523 * involved is passed as a parameter to this function
GordonSin 0:0ed2a7c7190c 524 */
GordonSin 0:0ed2a7c7190c 525 static err_t
GordonSin 0:0ed2a7c7190c 526 tcp_timewait_input(struct tcp_pcb *pcb)
GordonSin 0:0ed2a7c7190c 527 {
GordonSin 0:0ed2a7c7190c 528 /* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */
GordonSin 0:0ed2a7c7190c 529 /* RFC 793 3.9 Event Processing - Segment Arrives:
GordonSin 0:0ed2a7c7190c 530 * - first check sequence number - we skip that one in TIME_WAIT (always
GordonSin 0:0ed2a7c7190c 531 * acceptable since we only send ACKs)
GordonSin 0:0ed2a7c7190c 532 * - second check the RST bit (... return) */
GordonSin 0:0ed2a7c7190c 533 if (flags & TCP_RST) {
GordonSin 0:0ed2a7c7190c 534 return ERR_OK;
GordonSin 0:0ed2a7c7190c 535 }
GordonSin 0:0ed2a7c7190c 536 /* - fourth, check the SYN bit, */
GordonSin 0:0ed2a7c7190c 537 if (flags & TCP_SYN) {
GordonSin 0:0ed2a7c7190c 538 /* If an incoming segment is not acceptable, an acknowledgment
GordonSin 0:0ed2a7c7190c 539 should be sent in reply */
GordonSin 0:0ed2a7c7190c 540 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
GordonSin 0:0ed2a7c7190c 541 /* If the SYN is in the window it is an error, send a reset */
GordonSin 0:0ed2a7c7190c 542 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
GordonSin 0:0ed2a7c7190c 543 tcphdr->dest, tcphdr->src);
GordonSin 0:0ed2a7c7190c 544 return ERR_OK;
GordonSin 0:0ed2a7c7190c 545 }
GordonSin 0:0ed2a7c7190c 546 } else if (flags & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 547 /* - eighth, check the FIN bit: Remain in the TIME-WAIT state.
GordonSin 0:0ed2a7c7190c 548 Restart the 2 MSL time-wait timeout.*/
GordonSin 0:0ed2a7c7190c 549 pcb->tmr = tcp_ticks;
GordonSin 0:0ed2a7c7190c 550 }
GordonSin 0:0ed2a7c7190c 551
GordonSin 0:0ed2a7c7190c 552 if ((tcplen > 0)) {
GordonSin 0:0ed2a7c7190c 553 /* Acknowledge data, FIN or out-of-window SYN */
GordonSin 0:0ed2a7c7190c 554 pcb->flags |= TF_ACK_NOW;
GordonSin 0:0ed2a7c7190c 555 return tcp_output(pcb);
GordonSin 0:0ed2a7c7190c 556 }
GordonSin 0:0ed2a7c7190c 557 return ERR_OK;
GordonSin 0:0ed2a7c7190c 558 }
GordonSin 0:0ed2a7c7190c 559
GordonSin 0:0ed2a7c7190c 560 /**
GordonSin 0:0ed2a7c7190c 561 * Implements the TCP state machine. Called by tcp_input. In some
GordonSin 0:0ed2a7c7190c 562 * states tcp_receive() is called to receive data. The tcp_seg
GordonSin 0:0ed2a7c7190c 563 * argument will be freed by the caller (tcp_input()) unless the
GordonSin 0:0ed2a7c7190c 564 * recv_data pointer in the pcb is set.
GordonSin 0:0ed2a7c7190c 565 *
GordonSin 0:0ed2a7c7190c 566 * @param pcb the tcp_pcb for which a segment arrived
GordonSin 0:0ed2a7c7190c 567 *
GordonSin 0:0ed2a7c7190c 568 * @note the segment which arrived is saved in global variables, therefore only the pcb
GordonSin 0:0ed2a7c7190c 569 * involved is passed as a parameter to this function
GordonSin 0:0ed2a7c7190c 570 */
GordonSin 0:0ed2a7c7190c 571 static err_t
GordonSin 0:0ed2a7c7190c 572 tcp_process(struct tcp_pcb *pcb)
GordonSin 0:0ed2a7c7190c 573 {
GordonSin 0:0ed2a7c7190c 574 struct tcp_seg *rseg;
GordonSin 0:0ed2a7c7190c 575 u8_t acceptable = 0;
GordonSin 0:0ed2a7c7190c 576 err_t err;
GordonSin 0:0ed2a7c7190c 577
GordonSin 0:0ed2a7c7190c 578 err = ERR_OK;
GordonSin 0:0ed2a7c7190c 579
GordonSin 0:0ed2a7c7190c 580 /* Process incoming RST segments. */
GordonSin 0:0ed2a7c7190c 581 if (flags & TCP_RST) {
GordonSin 0:0ed2a7c7190c 582 /* First, determine if the reset is acceptable. */
GordonSin 0:0ed2a7c7190c 583 if (pcb->state == SYN_SENT) {
GordonSin 0:0ed2a7c7190c 584 if (ackno == pcb->snd_nxt) {
GordonSin 0:0ed2a7c7190c 585 acceptable = 1;
GordonSin 0:0ed2a7c7190c 586 }
GordonSin 0:0ed2a7c7190c 587 } else {
GordonSin 0:0ed2a7c7190c 588 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
GordonSin 0:0ed2a7c7190c 589 pcb->rcv_nxt+pcb->rcv_wnd)) {
GordonSin 0:0ed2a7c7190c 590 acceptable = 1;
GordonSin 0:0ed2a7c7190c 591 }
GordonSin 0:0ed2a7c7190c 592 }
GordonSin 0:0ed2a7c7190c 593
GordonSin 0:0ed2a7c7190c 594 if (acceptable) {
GordonSin 0:0ed2a7c7190c 595 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
GordonSin 0:0ed2a7c7190c 596 LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
GordonSin 0:0ed2a7c7190c 597 recv_flags |= TF_RESET;
GordonSin 0:0ed2a7c7190c 598 pcb->flags &= ~TF_ACK_DELAY;
GordonSin 0:0ed2a7c7190c 599 return ERR_RST;
GordonSin 0:0ed2a7c7190c 600 } else {
GordonSin 0:0ed2a7c7190c 601 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 602 seqno, pcb->rcv_nxt));
GordonSin 0:0ed2a7c7190c 603 LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 604 seqno, pcb->rcv_nxt));
GordonSin 0:0ed2a7c7190c 605 return ERR_OK;
GordonSin 0:0ed2a7c7190c 606 }
GordonSin 0:0ed2a7c7190c 607 }
GordonSin 0:0ed2a7c7190c 608
GordonSin 0:0ed2a7c7190c 609 if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
GordonSin 0:0ed2a7c7190c 610 /* Cope with new connection attempt after remote end crashed */
GordonSin 0:0ed2a7c7190c 611 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 612 return ERR_OK;
GordonSin 0:0ed2a7c7190c 613 }
GordonSin 0:0ed2a7c7190c 614
GordonSin 0:0ed2a7c7190c 615 if ((pcb->flags & TF_RXCLOSED) == 0) {
GordonSin 0:0ed2a7c7190c 616 /* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
GordonSin 0:0ed2a7c7190c 617 pcb->tmr = tcp_ticks;
GordonSin 0:0ed2a7c7190c 618 }
GordonSin 0:0ed2a7c7190c 619 pcb->keep_cnt_sent = 0;
GordonSin 0:0ed2a7c7190c 620
GordonSin 0:0ed2a7c7190c 621 tcp_parseopt(pcb);
GordonSin 0:0ed2a7c7190c 622
GordonSin 0:0ed2a7c7190c 623 /* Do different things depending on the TCP state. */
GordonSin 0:0ed2a7c7190c 624 switch (pcb->state) {
GordonSin 0:0ed2a7c7190c 625 case SYN_SENT:
GordonSin 0:0ed2a7c7190c 626 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
GordonSin 0:0ed2a7c7190c 627 pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
GordonSin 0:0ed2a7c7190c 628 /* received SYN ACK with expected sequence number? */
GordonSin 0:0ed2a7c7190c 629 if ((flags & TCP_ACK) && (flags & TCP_SYN)
GordonSin 0:0ed2a7c7190c 630 && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
GordonSin 0:0ed2a7c7190c 631 pcb->snd_buf++;
GordonSin 0:0ed2a7c7190c 632 pcb->rcv_nxt = seqno + 1;
GordonSin 0:0ed2a7c7190c 633 pcb->rcv_ann_right_edge = pcb->rcv_nxt;
GordonSin 0:0ed2a7c7190c 634 pcb->lastack = ackno;
GordonSin 0:0ed2a7c7190c 635 pcb->snd_wnd = tcphdr->wnd;
GordonSin 0:0ed2a7c7190c 636 pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
GordonSin 0:0ed2a7c7190c 637 pcb->state = ESTABLISHED;
GordonSin 0:0ed2a7c7190c 638
GordonSin 0:0ed2a7c7190c 639 #if TCP_CALCULATE_EFF_SEND_MSS
GordonSin 0:0ed2a7c7190c 640 pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
GordonSin 0:0ed2a7c7190c 641 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
GordonSin 0:0ed2a7c7190c 642
GordonSin 0:0ed2a7c7190c 643 /* Set ssthresh again after changing pcb->mss (already set in tcp_connect
GordonSin 0:0ed2a7c7190c 644 * but for the default value of pcb->mss) */
GordonSin 0:0ed2a7c7190c 645 pcb->ssthresh = pcb->mss * 10;
GordonSin 0:0ed2a7c7190c 646
GordonSin 0:0ed2a7c7190c 647 pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
GordonSin 0:0ed2a7c7190c 648 LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
GordonSin 0:0ed2a7c7190c 649 --pcb->snd_queuelen;
GordonSin 0:0ed2a7c7190c 650 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
GordonSin 0:0ed2a7c7190c 651 rseg = pcb->unacked;
GordonSin 0:0ed2a7c7190c 652 pcb->unacked = rseg->next;
GordonSin 0:0ed2a7c7190c 653
GordonSin 0:0ed2a7c7190c 654 /* If there's nothing left to acknowledge, stop the retransmit
GordonSin 0:0ed2a7c7190c 655 timer, otherwise reset it to start again */
GordonSin 0:0ed2a7c7190c 656 if(pcb->unacked == NULL)
GordonSin 0:0ed2a7c7190c 657 pcb->rtime = -1;
GordonSin 0:0ed2a7c7190c 658 else {
GordonSin 0:0ed2a7c7190c 659 pcb->rtime = 0;
GordonSin 0:0ed2a7c7190c 660 pcb->nrtx = 0;
GordonSin 0:0ed2a7c7190c 661 }
GordonSin 0:0ed2a7c7190c 662
GordonSin 0:0ed2a7c7190c 663 tcp_seg_free(rseg);
GordonSin 0:0ed2a7c7190c 664
GordonSin 0:0ed2a7c7190c 665 /* Call the user specified function to call when sucessfully
GordonSin 0:0ed2a7c7190c 666 * connected. */
GordonSin 0:0ed2a7c7190c 667 TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
GordonSin 0:0ed2a7c7190c 668 if (err == ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 669 return ERR_ABRT;
GordonSin 0:0ed2a7c7190c 670 }
GordonSin 0:0ed2a7c7190c 671 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 672 }
GordonSin 0:0ed2a7c7190c 673 /* received ACK? possibly a half-open connection */
GordonSin 0:0ed2a7c7190c 674 else if (flags & TCP_ACK) {
GordonSin 0:0ed2a7c7190c 675 /* send a RST to bring the other side in a non-synchronized state. */
GordonSin 0:0ed2a7c7190c 676 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
GordonSin 0:0ed2a7c7190c 677 tcphdr->dest, tcphdr->src);
GordonSin 0:0ed2a7c7190c 678 }
GordonSin 0:0ed2a7c7190c 679 break;
GordonSin 0:0ed2a7c7190c 680 case SYN_RCVD:
GordonSin 0:0ed2a7c7190c 681 if (flags & TCP_ACK) {
GordonSin 0:0ed2a7c7190c 682 /* expected ACK number? */
GordonSin 0:0ed2a7c7190c 683 if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
GordonSin 0:0ed2a7c7190c 684 u16_t old_cwnd;
GordonSin 0:0ed2a7c7190c 685 pcb->state = ESTABLISHED;
GordonSin 0:0ed2a7c7190c 686 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
GordonSin 0:0ed2a7c7190c 687 #if LWIP_CALLBACK_API
GordonSin 0:0ed2a7c7190c 688 LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
GordonSin 0:0ed2a7c7190c 689 #endif
GordonSin 0:0ed2a7c7190c 690 /* Call the accept function. */
GordonSin 0:0ed2a7c7190c 691 TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
GordonSin 0:0ed2a7c7190c 692 if (err != ERR_OK) {
GordonSin 0:0ed2a7c7190c 693 /* If the accept function returns with an error, we abort
GordonSin 0:0ed2a7c7190c 694 * the connection. */
GordonSin 0:0ed2a7c7190c 695 /* Already aborted? */
GordonSin 0:0ed2a7c7190c 696 if (err != ERR_ABRT) {
GordonSin 0:0ed2a7c7190c 697 tcp_abort(pcb);
GordonSin 0:0ed2a7c7190c 698 }
GordonSin 0:0ed2a7c7190c 699 return ERR_ABRT;
GordonSin 0:0ed2a7c7190c 700 }
GordonSin 0:0ed2a7c7190c 701 old_cwnd = pcb->cwnd;
GordonSin 0:0ed2a7c7190c 702 /* If there was any data contained within this ACK,
GordonSin 0:0ed2a7c7190c 703 * we'd better pass it on to the application as well. */
GordonSin 0:0ed2a7c7190c 704 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 705
GordonSin 0:0ed2a7c7190c 706 /* Prevent ACK for SYN to generate a sent event */
GordonSin 0:0ed2a7c7190c 707 if (pcb->acked != 0) {
GordonSin 0:0ed2a7c7190c 708 pcb->acked--;
GordonSin 0:0ed2a7c7190c 709 }
GordonSin 0:0ed2a7c7190c 710
GordonSin 0:0ed2a7c7190c 711 pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
GordonSin 0:0ed2a7c7190c 712
GordonSin 0:0ed2a7c7190c 713 if (recv_flags & TF_GOT_FIN) {
GordonSin 0:0ed2a7c7190c 714 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 715 pcb->state = CLOSE_WAIT;
GordonSin 0:0ed2a7c7190c 716 }
GordonSin 0:0ed2a7c7190c 717 } else {
GordonSin 0:0ed2a7c7190c 718 /* incorrect ACK number, send RST */
GordonSin 0:0ed2a7c7190c 719 tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
GordonSin 0:0ed2a7c7190c 720 tcphdr->dest, tcphdr->src);
GordonSin 0:0ed2a7c7190c 721 }
GordonSin 0:0ed2a7c7190c 722 } else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
GordonSin 0:0ed2a7c7190c 723 /* Looks like another copy of the SYN - retransmit our SYN-ACK */
GordonSin 0:0ed2a7c7190c 724 tcp_rexmit(pcb);
GordonSin 0:0ed2a7c7190c 725 }
GordonSin 0:0ed2a7c7190c 726 break;
GordonSin 0:0ed2a7c7190c 727 case CLOSE_WAIT:
GordonSin 0:0ed2a7c7190c 728 /* FALLTHROUGH */
GordonSin 0:0ed2a7c7190c 729 case ESTABLISHED:
GordonSin 0:0ed2a7c7190c 730 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 731 if (recv_flags & TF_GOT_FIN) { /* passive close */
GordonSin 0:0ed2a7c7190c 732 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 733 pcb->state = CLOSE_WAIT;
GordonSin 0:0ed2a7c7190c 734 }
GordonSin 0:0ed2a7c7190c 735 break;
GordonSin 0:0ed2a7c7190c 736 case FIN_WAIT_1:
GordonSin 0:0ed2a7c7190c 737 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 738 if (recv_flags & TF_GOT_FIN) {
GordonSin 0:0ed2a7c7190c 739 if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
GordonSin 0:0ed2a7c7190c 740 LWIP_DEBUGF(TCP_DEBUG,
GordonSin 0:0ed2a7c7190c 741 ("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
GordonSin 0:0ed2a7c7190c 742 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 743 tcp_pcb_purge(pcb);
GordonSin 0:0ed2a7c7190c 744 TCP_RMV(&tcp_active_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 745 pcb->state = TIME_WAIT;
GordonSin 0:0ed2a7c7190c 746 TCP_REG(&tcp_tw_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 747 } else {
GordonSin 0:0ed2a7c7190c 748 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 749 pcb->state = CLOSING;
GordonSin 0:0ed2a7c7190c 750 }
GordonSin 0:0ed2a7c7190c 751 } else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
GordonSin 0:0ed2a7c7190c 752 pcb->state = FIN_WAIT_2;
GordonSin 0:0ed2a7c7190c 753 }
GordonSin 0:0ed2a7c7190c 754 break;
GordonSin 0:0ed2a7c7190c 755 case FIN_WAIT_2:
GordonSin 0:0ed2a7c7190c 756 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 757 if (recv_flags & TF_GOT_FIN) {
GordonSin 0:0ed2a7c7190c 758 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
GordonSin 0:0ed2a7c7190c 759 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 760 tcp_pcb_purge(pcb);
GordonSin 0:0ed2a7c7190c 761 TCP_RMV(&tcp_active_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 762 pcb->state = TIME_WAIT;
GordonSin 0:0ed2a7c7190c 763 TCP_REG(&tcp_tw_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 764 }
GordonSin 0:0ed2a7c7190c 765 break;
GordonSin 0:0ed2a7c7190c 766 case CLOSING:
GordonSin 0:0ed2a7c7190c 767 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 768 if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
GordonSin 0:0ed2a7c7190c 769 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
GordonSin 0:0ed2a7c7190c 770 tcp_pcb_purge(pcb);
GordonSin 0:0ed2a7c7190c 771 TCP_RMV(&tcp_active_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 772 pcb->state = TIME_WAIT;
GordonSin 0:0ed2a7c7190c 773 TCP_REG(&tcp_tw_pcbs, pcb);
GordonSin 0:0ed2a7c7190c 774 }
GordonSin 0:0ed2a7c7190c 775 break;
GordonSin 0:0ed2a7c7190c 776 case LAST_ACK:
GordonSin 0:0ed2a7c7190c 777 tcp_receive(pcb);
GordonSin 0:0ed2a7c7190c 778 if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
GordonSin 0:0ed2a7c7190c 779 LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
GordonSin 0:0ed2a7c7190c 780 /* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
GordonSin 0:0ed2a7c7190c 781 recv_flags |= TF_CLOSED;
GordonSin 0:0ed2a7c7190c 782 }
GordonSin 0:0ed2a7c7190c 783 break;
GordonSin 0:0ed2a7c7190c 784 default:
GordonSin 0:0ed2a7c7190c 785 break;
GordonSin 0:0ed2a7c7190c 786 }
GordonSin 0:0ed2a7c7190c 787 return ERR_OK;
GordonSin 0:0ed2a7c7190c 788 }
GordonSin 0:0ed2a7c7190c 789
GordonSin 0:0ed2a7c7190c 790 #if TCP_QUEUE_OOSEQ
GordonSin 0:0ed2a7c7190c 791 /**
GordonSin 0:0ed2a7c7190c 792 * Insert segment into the list (segments covered with new one will be deleted)
GordonSin 0:0ed2a7c7190c 793 *
GordonSin 0:0ed2a7c7190c 794 * Called from tcp_receive()
GordonSin 0:0ed2a7c7190c 795 */
GordonSin 0:0ed2a7c7190c 796 static void
GordonSin 0:0ed2a7c7190c 797 tcp_oos_insert_segment(struct tcp_seg *cseg, struct tcp_seg *next)
GordonSin 0:0ed2a7c7190c 798 {
GordonSin 0:0ed2a7c7190c 799 struct tcp_seg *old_seg;
GordonSin 0:0ed2a7c7190c 800
GordonSin 0:0ed2a7c7190c 801 if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 802 /* received segment overlaps all following segments */
GordonSin 0:0ed2a7c7190c 803 tcp_segs_free(next);
GordonSin 0:0ed2a7c7190c 804 next = NULL;
GordonSin 0:0ed2a7c7190c 805 }
GordonSin 0:0ed2a7c7190c 806 else {
GordonSin 0:0ed2a7c7190c 807 /* delete some following segments
GordonSin 0:0ed2a7c7190c 808 oos queue may have segments with FIN flag */
GordonSin 0:0ed2a7c7190c 809 while (next &&
GordonSin 0:0ed2a7c7190c 810 TCP_SEQ_GEQ((seqno + cseg->len),
GordonSin 0:0ed2a7c7190c 811 (next->tcphdr->seqno + next->len))) {
GordonSin 0:0ed2a7c7190c 812 /* cseg with FIN already processed */
GordonSin 0:0ed2a7c7190c 813 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 814 TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
GordonSin 0:0ed2a7c7190c 815 }
GordonSin 0:0ed2a7c7190c 816 old_seg = next;
GordonSin 0:0ed2a7c7190c 817 next = next->next;
GordonSin 0:0ed2a7c7190c 818 tcp_seg_free(old_seg);
GordonSin 0:0ed2a7c7190c 819 }
GordonSin 0:0ed2a7c7190c 820 if (next &&
GordonSin 0:0ed2a7c7190c 821 TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
GordonSin 0:0ed2a7c7190c 822 /* We need to trim the incoming segment. */
GordonSin 0:0ed2a7c7190c 823 cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
GordonSin 0:0ed2a7c7190c 824 pbuf_realloc(cseg->p, cseg->len);
GordonSin 0:0ed2a7c7190c 825 }
GordonSin 0:0ed2a7c7190c 826 }
GordonSin 0:0ed2a7c7190c 827 cseg->next = next;
GordonSin 0:0ed2a7c7190c 828 }
GordonSin 0:0ed2a7c7190c 829 #endif /* TCP_QUEUE_OOSEQ */
GordonSin 0:0ed2a7c7190c 830
GordonSin 0:0ed2a7c7190c 831 /**
GordonSin 0:0ed2a7c7190c 832 * Called by tcp_process. Checks if the given segment is an ACK for outstanding
GordonSin 0:0ed2a7c7190c 833 * data, and if so frees the memory of the buffered data. Next, is places the
GordonSin 0:0ed2a7c7190c 834 * segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
GordonSin 0:0ed2a7c7190c 835 * is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
GordonSin 0:0ed2a7c7190c 836 * i it has been removed from the buffer.
GordonSin 0:0ed2a7c7190c 837 *
GordonSin 0:0ed2a7c7190c 838 * If the incoming segment constitutes an ACK for a segment that was used for RTT
GordonSin 0:0ed2a7c7190c 839 * estimation, the RTT is estimated here as well.
GordonSin 0:0ed2a7c7190c 840 *
GordonSin 0:0ed2a7c7190c 841 * Called from tcp_process().
GordonSin 0:0ed2a7c7190c 842 */
GordonSin 0:0ed2a7c7190c 843 static void
GordonSin 0:0ed2a7c7190c 844 tcp_receive(struct tcp_pcb *pcb)
GordonSin 0:0ed2a7c7190c 845 {
GordonSin 0:0ed2a7c7190c 846 struct tcp_seg *next;
GordonSin 0:0ed2a7c7190c 847 #if TCP_QUEUE_OOSEQ
GordonSin 0:0ed2a7c7190c 848 struct tcp_seg *prev, *cseg;
GordonSin 0:0ed2a7c7190c 849 #endif /* TCP_QUEUE_OOSEQ */
GordonSin 0:0ed2a7c7190c 850 struct pbuf *p;
GordonSin 0:0ed2a7c7190c 851 s32_t off;
GordonSin 0:0ed2a7c7190c 852 s16_t m;
GordonSin 0:0ed2a7c7190c 853 u32_t right_wnd_edge;
GordonSin 0:0ed2a7c7190c 854 u16_t new_tot_len;
GordonSin 0:0ed2a7c7190c 855 int found_dupack = 0;
GordonSin 0:0ed2a7c7190c 856
GordonSin 0:0ed2a7c7190c 857 if (flags & TCP_ACK) {
GordonSin 0:0ed2a7c7190c 858 right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;
GordonSin 0:0ed2a7c7190c 859
GordonSin 0:0ed2a7c7190c 860 /* Update window. */
GordonSin 0:0ed2a7c7190c 861 if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
GordonSin 0:0ed2a7c7190c 862 (pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
GordonSin 0:0ed2a7c7190c 863 (pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
GordonSin 0:0ed2a7c7190c 864 pcb->snd_wnd = tcphdr->wnd;
GordonSin 0:0ed2a7c7190c 865 pcb->snd_wl1 = seqno;
GordonSin 0:0ed2a7c7190c 866 pcb->snd_wl2 = ackno;
GordonSin 0:0ed2a7c7190c 867 if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
GordonSin 0:0ed2a7c7190c 868 pcb->persist_backoff = 0;
GordonSin 0:0ed2a7c7190c 869 }
GordonSin 0:0ed2a7c7190c 870 LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
GordonSin 0:0ed2a7c7190c 871 #if TCP_WND_DEBUG
GordonSin 0:0ed2a7c7190c 872 } else {
GordonSin 0:0ed2a7c7190c 873 if (pcb->snd_wnd != tcphdr->wnd) {
GordonSin 0:0ed2a7c7190c 874 LWIP_DEBUGF(TCP_WND_DEBUG,
GordonSin 0:0ed2a7c7190c 875 ("tcp_receive: no window update lastack %"U32_F" ackno %"
GordonSin 0:0ed2a7c7190c 876 U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 877 pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
GordonSin 0:0ed2a7c7190c 878 }
GordonSin 0:0ed2a7c7190c 879 #endif /* TCP_WND_DEBUG */
GordonSin 0:0ed2a7c7190c 880 }
GordonSin 0:0ed2a7c7190c 881
GordonSin 0:0ed2a7c7190c 882 /* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
GordonSin 0:0ed2a7c7190c 883 * duplicate ack if:
GordonSin 0:0ed2a7c7190c 884 * 1) It doesn't ACK new data
GordonSin 0:0ed2a7c7190c 885 * 2) length of received packet is zero (i.e. no payload)
GordonSin 0:0ed2a7c7190c 886 * 3) the advertised window hasn't changed
GordonSin 0:0ed2a7c7190c 887 * 4) There is outstanding unacknowledged data (retransmission timer running)
GordonSin 0:0ed2a7c7190c 888 * 5) The ACK is == biggest ACK sequence number so far seen (snd_una)
GordonSin 0:0ed2a7c7190c 889 *
GordonSin 0:0ed2a7c7190c 890 * If it passes all five, should process as a dupack:
GordonSin 0:0ed2a7c7190c 891 * a) dupacks < 3: do nothing
GordonSin 0:0ed2a7c7190c 892 * b) dupacks == 3: fast retransmit
GordonSin 0:0ed2a7c7190c 893 * c) dupacks > 3: increase cwnd
GordonSin 0:0ed2a7c7190c 894 *
GordonSin 0:0ed2a7c7190c 895 * If it only passes 1-3, should reset dupack counter (and add to
GordonSin 0:0ed2a7c7190c 896 * stats, which we don't do in lwIP)
GordonSin 0:0ed2a7c7190c 897 *
GordonSin 0:0ed2a7c7190c 898 * If it only passes 1, should reset dupack counter
GordonSin 0:0ed2a7c7190c 899 *
GordonSin 0:0ed2a7c7190c 900 */
GordonSin 0:0ed2a7c7190c 901
GordonSin 0:0ed2a7c7190c 902 /* Clause 1 */
GordonSin 0:0ed2a7c7190c 903 if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {
GordonSin 0:0ed2a7c7190c 904 pcb->acked = 0;
GordonSin 0:0ed2a7c7190c 905 /* Clause 2 */
GordonSin 0:0ed2a7c7190c 906 if (tcplen == 0) {
GordonSin 0:0ed2a7c7190c 907 /* Clause 3 */
GordonSin 0:0ed2a7c7190c 908 if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
GordonSin 0:0ed2a7c7190c 909 /* Clause 4 */
GordonSin 0:0ed2a7c7190c 910 if (pcb->rtime >= 0) {
GordonSin 0:0ed2a7c7190c 911 /* Clause 5 */
GordonSin 0:0ed2a7c7190c 912 if (pcb->lastack == ackno) {
GordonSin 0:0ed2a7c7190c 913 found_dupack = 1;
GordonSin 0:0ed2a7c7190c 914 if (pcb->dupacks + 1 > pcb->dupacks)
GordonSin 0:0ed2a7c7190c 915 ++pcb->dupacks;
GordonSin 0:0ed2a7c7190c 916 if (pcb->dupacks > 3) {
GordonSin 0:0ed2a7c7190c 917 /* Inflate the congestion window, but not if it means that
GordonSin 0:0ed2a7c7190c 918 the value overflows. */
GordonSin 0:0ed2a7c7190c 919 if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
GordonSin 0:0ed2a7c7190c 920 pcb->cwnd += pcb->mss;
GordonSin 0:0ed2a7c7190c 921 }
GordonSin 0:0ed2a7c7190c 922 } else if (pcb->dupacks == 3) {
GordonSin 0:0ed2a7c7190c 923 /* Do fast retransmit */
GordonSin 0:0ed2a7c7190c 924 tcp_rexmit_fast(pcb);
GordonSin 0:0ed2a7c7190c 925 }
GordonSin 0:0ed2a7c7190c 926 }
GordonSin 0:0ed2a7c7190c 927 }
GordonSin 0:0ed2a7c7190c 928 }
GordonSin 0:0ed2a7c7190c 929 }
GordonSin 0:0ed2a7c7190c 930 /* If Clause (1) or more is true, but not a duplicate ack, reset
GordonSin 0:0ed2a7c7190c 931 * count of consecutive duplicate acks */
GordonSin 0:0ed2a7c7190c 932 if (!found_dupack) {
GordonSin 0:0ed2a7c7190c 933 pcb->dupacks = 0;
GordonSin 0:0ed2a7c7190c 934 }
GordonSin 0:0ed2a7c7190c 935 } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){
GordonSin 0:0ed2a7c7190c 936 /* We come here when the ACK acknowledges new data. */
GordonSin 0:0ed2a7c7190c 937
GordonSin 0:0ed2a7c7190c 938 /* Reset the "IN Fast Retransmit" flag, since we are no longer
GordonSin 0:0ed2a7c7190c 939 in fast retransmit. Also reset the congestion window to the
GordonSin 0:0ed2a7c7190c 940 slow start threshold. */
GordonSin 0:0ed2a7c7190c 941 if (pcb->flags & TF_INFR) {
GordonSin 0:0ed2a7c7190c 942 pcb->flags &= ~TF_INFR;
GordonSin 0:0ed2a7c7190c 943 pcb->cwnd = pcb->ssthresh;
GordonSin 0:0ed2a7c7190c 944 }
GordonSin 0:0ed2a7c7190c 945
GordonSin 0:0ed2a7c7190c 946 /* Reset the number of retransmissions. */
GordonSin 0:0ed2a7c7190c 947 pcb->nrtx = 0;
GordonSin 0:0ed2a7c7190c 948
GordonSin 0:0ed2a7c7190c 949 /* Reset the retransmission time-out. */
GordonSin 0:0ed2a7c7190c 950 pcb->rto = (pcb->sa >> 3) + pcb->sv;
GordonSin 0:0ed2a7c7190c 951
GordonSin 0:0ed2a7c7190c 952 /* Update the send buffer space. Diff between the two can never exceed 64K? */
GordonSin 0:0ed2a7c7190c 953 pcb->acked = (u16_t)(ackno - pcb->lastack);
GordonSin 0:0ed2a7c7190c 954
GordonSin 0:0ed2a7c7190c 955 pcb->snd_buf += pcb->acked;
GordonSin 0:0ed2a7c7190c 956
GordonSin 0:0ed2a7c7190c 957 /* Reset the fast retransmit variables. */
GordonSin 0:0ed2a7c7190c 958 pcb->dupacks = 0;
GordonSin 0:0ed2a7c7190c 959 pcb->lastack = ackno;
GordonSin 0:0ed2a7c7190c 960
GordonSin 0:0ed2a7c7190c 961 /* Update the congestion control variables (cwnd and
GordonSin 0:0ed2a7c7190c 962 ssthresh). */
GordonSin 0:0ed2a7c7190c 963 if (pcb->state >= ESTABLISHED) {
GordonSin 0:0ed2a7c7190c 964 if (pcb->cwnd < pcb->ssthresh) {
GordonSin 0:0ed2a7c7190c 965 if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
GordonSin 0:0ed2a7c7190c 966 pcb->cwnd += pcb->mss;
GordonSin 0:0ed2a7c7190c 967 }
GordonSin 0:0ed2a7c7190c 968 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
GordonSin 0:0ed2a7c7190c 969 } else {
GordonSin 0:0ed2a7c7190c 970 u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
GordonSin 0:0ed2a7c7190c 971 if (new_cwnd > pcb->cwnd) {
GordonSin 0:0ed2a7c7190c 972 pcb->cwnd = new_cwnd;
GordonSin 0:0ed2a7c7190c 973 }
GordonSin 0:0ed2a7c7190c 974 LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
GordonSin 0:0ed2a7c7190c 975 }
GordonSin 0:0ed2a7c7190c 976 }
GordonSin 0:0ed2a7c7190c 977 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
GordonSin 0:0ed2a7c7190c 978 ackno,
GordonSin 0:0ed2a7c7190c 979 pcb->unacked != NULL?
GordonSin 0:0ed2a7c7190c 980 ntohl(pcb->unacked->tcphdr->seqno): 0,
GordonSin 0:0ed2a7c7190c 981 pcb->unacked != NULL?
GordonSin 0:0ed2a7c7190c 982 ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
GordonSin 0:0ed2a7c7190c 983
GordonSin 0:0ed2a7c7190c 984 /* Remove segment from the unacknowledged list if the incoming
GordonSin 0:0ed2a7c7190c 985 ACK acknowlegdes them. */
GordonSin 0:0ed2a7c7190c 986 while (pcb->unacked != NULL &&
GordonSin 0:0ed2a7c7190c 987 TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
GordonSin 0:0ed2a7c7190c 988 TCP_TCPLEN(pcb->unacked), ackno)) {
GordonSin 0:0ed2a7c7190c 989 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
GordonSin 0:0ed2a7c7190c 990 ntohl(pcb->unacked->tcphdr->seqno),
GordonSin 0:0ed2a7c7190c 991 ntohl(pcb->unacked->tcphdr->seqno) +
GordonSin 0:0ed2a7c7190c 992 TCP_TCPLEN(pcb->unacked)));
GordonSin 0:0ed2a7c7190c 993
GordonSin 0:0ed2a7c7190c 994 next = pcb->unacked;
GordonSin 0:0ed2a7c7190c 995 pcb->unacked = pcb->unacked->next;
GordonSin 0:0ed2a7c7190c 996
GordonSin 0:0ed2a7c7190c 997 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
GordonSin 0:0ed2a7c7190c 998 LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
GordonSin 0:0ed2a7c7190c 999 /* Prevent ACK for FIN to generate a sent event */
GordonSin 0:0ed2a7c7190c 1000 if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
GordonSin 0:0ed2a7c7190c 1001 pcb->acked--;
GordonSin 0:0ed2a7c7190c 1002 }
GordonSin 0:0ed2a7c7190c 1003
GordonSin 0:0ed2a7c7190c 1004 pcb->snd_queuelen -= pbuf_clen(next->p);
GordonSin 0:0ed2a7c7190c 1005 tcp_seg_free(next);
GordonSin 0:0ed2a7c7190c 1006
GordonSin 0:0ed2a7c7190c 1007 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
GordonSin 0:0ed2a7c7190c 1008 if (pcb->snd_queuelen != 0) {
GordonSin 0:0ed2a7c7190c 1009 LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
GordonSin 0:0ed2a7c7190c 1010 pcb->unsent != NULL);
GordonSin 0:0ed2a7c7190c 1011 }
GordonSin 0:0ed2a7c7190c 1012 }
GordonSin 0:0ed2a7c7190c 1013
GordonSin 0:0ed2a7c7190c 1014 /* If there's nothing left to acknowledge, stop the retransmit
GordonSin 0:0ed2a7c7190c 1015 timer, otherwise reset it to start again */
GordonSin 0:0ed2a7c7190c 1016 if(pcb->unacked == NULL)
GordonSin 0:0ed2a7c7190c 1017 pcb->rtime = -1;
GordonSin 0:0ed2a7c7190c 1018 else
GordonSin 0:0ed2a7c7190c 1019 pcb->rtime = 0;
GordonSin 0:0ed2a7c7190c 1020
GordonSin 0:0ed2a7c7190c 1021 pcb->polltmr = 0;
GordonSin 0:0ed2a7c7190c 1022 } else {
GordonSin 0:0ed2a7c7190c 1023 /* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
GordonSin 0:0ed2a7c7190c 1024 pcb->acked = 0;
GordonSin 0:0ed2a7c7190c 1025 }
GordonSin 0:0ed2a7c7190c 1026
GordonSin 0:0ed2a7c7190c 1027 /* We go through the ->unsent list to see if any of the segments
GordonSin 0:0ed2a7c7190c 1028 on the list are acknowledged by the ACK. This may seem
GordonSin 0:0ed2a7c7190c 1029 strange since an "unsent" segment shouldn't be acked. The
GordonSin 0:0ed2a7c7190c 1030 rationale is that lwIP puts all outstanding segments on the
GordonSin 0:0ed2a7c7190c 1031 ->unsent list after a retransmission, so these segments may
GordonSin 0:0ed2a7c7190c 1032 in fact have been sent once. */
GordonSin 0:0ed2a7c7190c 1033 while (pcb->unsent != NULL &&
GordonSin 0:0ed2a7c7190c 1034 TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
GordonSin 0:0ed2a7c7190c 1035 TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
GordonSin 0:0ed2a7c7190c 1036 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
GordonSin 0:0ed2a7c7190c 1037 ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
GordonSin 0:0ed2a7c7190c 1038 TCP_TCPLEN(pcb->unsent)));
GordonSin 0:0ed2a7c7190c 1039
GordonSin 0:0ed2a7c7190c 1040 next = pcb->unsent;
GordonSin 0:0ed2a7c7190c 1041 pcb->unsent = pcb->unsent->next;
GordonSin 0:0ed2a7c7190c 1042 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
GordonSin 0:0ed2a7c7190c 1043 LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
GordonSin 0:0ed2a7c7190c 1044 /* Prevent ACK for FIN to generate a sent event */
GordonSin 0:0ed2a7c7190c 1045 if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
GordonSin 0:0ed2a7c7190c 1046 pcb->acked--;
GordonSin 0:0ed2a7c7190c 1047 }
GordonSin 0:0ed2a7c7190c 1048 pcb->snd_queuelen -= pbuf_clen(next->p);
GordonSin 0:0ed2a7c7190c 1049 tcp_seg_free(next);
GordonSin 0:0ed2a7c7190c 1050 LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
GordonSin 0:0ed2a7c7190c 1051 if (pcb->snd_queuelen != 0) {
GordonSin 0:0ed2a7c7190c 1052 LWIP_ASSERT("tcp_receive: valid queue length",
GordonSin 0:0ed2a7c7190c 1053 pcb->unacked != NULL || pcb->unsent != NULL);
GordonSin 0:0ed2a7c7190c 1054 }
GordonSin 0:0ed2a7c7190c 1055 }
GordonSin 0:0ed2a7c7190c 1056 /* End of ACK for new data processing. */
GordonSin 0:0ed2a7c7190c 1057
GordonSin 0:0ed2a7c7190c 1058 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 1059 pcb->rttest, pcb->rtseq, ackno));
GordonSin 0:0ed2a7c7190c 1060
GordonSin 0:0ed2a7c7190c 1061 /* RTT estimation calculations. This is done by checking if the
GordonSin 0:0ed2a7c7190c 1062 incoming segment acknowledges the segment we use to take a
GordonSin 0:0ed2a7c7190c 1063 round-trip time measurement. */
GordonSin 0:0ed2a7c7190c 1064 if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {
GordonSin 0:0ed2a7c7190c 1065 /* diff between this shouldn't exceed 32K since this are tcp timer ticks
GordonSin 0:0ed2a7c7190c 1066 and a round-trip shouldn't be that long... */
GordonSin 0:0ed2a7c7190c 1067 m = (s16_t)(tcp_ticks - pcb->rttest);
GordonSin 0:0ed2a7c7190c 1068
GordonSin 0:0ed2a7c7190c 1069 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
GordonSin 0:0ed2a7c7190c 1070 m, m * TCP_SLOW_INTERVAL));
GordonSin 0:0ed2a7c7190c 1071
GordonSin 0:0ed2a7c7190c 1072 /* This is taken directly from VJs original code in his paper */
GordonSin 0:0ed2a7c7190c 1073 m = m - (pcb->sa >> 3);
GordonSin 0:0ed2a7c7190c 1074 pcb->sa += m;
GordonSin 0:0ed2a7c7190c 1075 if (m < 0) {
GordonSin 0:0ed2a7c7190c 1076 m = -m;
GordonSin 0:0ed2a7c7190c 1077 }
GordonSin 0:0ed2a7c7190c 1078 m = m - (pcb->sv >> 2);
GordonSin 0:0ed2a7c7190c 1079 pcb->sv += m;
GordonSin 0:0ed2a7c7190c 1080 pcb->rto = (pcb->sa >> 3) + pcb->sv;
GordonSin 0:0ed2a7c7190c 1081
GordonSin 0:0ed2a7c7190c 1082 LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
GordonSin 0:0ed2a7c7190c 1083 pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
GordonSin 0:0ed2a7c7190c 1084
GordonSin 0:0ed2a7c7190c 1085 pcb->rttest = 0;
GordonSin 0:0ed2a7c7190c 1086 }
GordonSin 0:0ed2a7c7190c 1087 }
GordonSin 0:0ed2a7c7190c 1088
GordonSin 0:0ed2a7c7190c 1089 /* If the incoming segment contains data, we must process it
GordonSin 0:0ed2a7c7190c 1090 further. */
GordonSin 0:0ed2a7c7190c 1091 if (tcplen > 0) {
GordonSin 0:0ed2a7c7190c 1092 /* This code basically does three things:
GordonSin 0:0ed2a7c7190c 1093
GordonSin 0:0ed2a7c7190c 1094 +) If the incoming segment contains data that is the next
GordonSin 0:0ed2a7c7190c 1095 in-sequence data, this data is passed to the application. This
GordonSin 0:0ed2a7c7190c 1096 might involve trimming the first edge of the data. The rcv_nxt
GordonSin 0:0ed2a7c7190c 1097 variable and the advertised window are adjusted.
GordonSin 0:0ed2a7c7190c 1098
GordonSin 0:0ed2a7c7190c 1099 +) If the incoming segment has data that is above the next
GordonSin 0:0ed2a7c7190c 1100 sequence number expected (->rcv_nxt), the segment is placed on
GordonSin 0:0ed2a7c7190c 1101 the ->ooseq queue. This is done by finding the appropriate
GordonSin 0:0ed2a7c7190c 1102 place in the ->ooseq queue (which is ordered by sequence
GordonSin 0:0ed2a7c7190c 1103 number) and trim the segment in both ends if needed. An
GordonSin 0:0ed2a7c7190c 1104 immediate ACK is sent to indicate that we received an
GordonSin 0:0ed2a7c7190c 1105 out-of-sequence segment.
GordonSin 0:0ed2a7c7190c 1106
GordonSin 0:0ed2a7c7190c 1107 +) Finally, we check if the first segment on the ->ooseq queue
GordonSin 0:0ed2a7c7190c 1108 now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
GordonSin 0:0ed2a7c7190c 1109 rcv_nxt > ooseq->seqno, we must trim the first edge of the
GordonSin 0:0ed2a7c7190c 1110 segment on ->ooseq before we adjust rcv_nxt. The data in the
GordonSin 0:0ed2a7c7190c 1111 segments that are now on sequence are chained onto the
GordonSin 0:0ed2a7c7190c 1112 incoming segment so that we only need to call the application
GordonSin 0:0ed2a7c7190c 1113 once.
GordonSin 0:0ed2a7c7190c 1114 */
GordonSin 0:0ed2a7c7190c 1115
GordonSin 0:0ed2a7c7190c 1116 /* First, we check if we must trim the first edge. We have to do
GordonSin 0:0ed2a7c7190c 1117 this if the sequence number of the incoming segment is less
GordonSin 0:0ed2a7c7190c 1118 than rcv_nxt, and the sequence number plus the length of the
GordonSin 0:0ed2a7c7190c 1119 segment is larger than rcv_nxt. */
GordonSin 0:0ed2a7c7190c 1120 /* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
GordonSin 0:0ed2a7c7190c 1121 if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
GordonSin 0:0ed2a7c7190c 1122 if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){
GordonSin 0:0ed2a7c7190c 1123 /* Trimming the first edge is done by pushing the payload
GordonSin 0:0ed2a7c7190c 1124 pointer in the pbuf downwards. This is somewhat tricky since
GordonSin 0:0ed2a7c7190c 1125 we do not want to discard the full contents of the pbuf up to
GordonSin 0:0ed2a7c7190c 1126 the new starting point of the data since we have to keep the
GordonSin 0:0ed2a7c7190c 1127 TCP header which is present in the first pbuf in the chain.
GordonSin 0:0ed2a7c7190c 1128
GordonSin 0:0ed2a7c7190c 1129 What is done is really quite a nasty hack: the first pbuf in
GordonSin 0:0ed2a7c7190c 1130 the pbuf chain is pointed to by inseg.p. Since we need to be
GordonSin 0:0ed2a7c7190c 1131 able to deallocate the whole pbuf, we cannot change this
GordonSin 0:0ed2a7c7190c 1132 inseg.p pointer to point to any of the later pbufs in the
GordonSin 0:0ed2a7c7190c 1133 chain. Instead, we point the ->payload pointer in the first
GordonSin 0:0ed2a7c7190c 1134 pbuf to data in one of the later pbufs. We also set the
GordonSin 0:0ed2a7c7190c 1135 inseg.data pointer to point to the right place. This way, the
GordonSin 0:0ed2a7c7190c 1136 ->p pointer will still point to the first pbuf, but the
GordonSin 0:0ed2a7c7190c 1137 ->p->payload pointer will point to data in another pbuf.
GordonSin 0:0ed2a7c7190c 1138
GordonSin 0:0ed2a7c7190c 1139 After we are done with adjusting the pbuf pointers we must
GordonSin 0:0ed2a7c7190c 1140 adjust the ->data pointer in the seg and the segment
GordonSin 0:0ed2a7c7190c 1141 length.*/
GordonSin 0:0ed2a7c7190c 1142
GordonSin 0:0ed2a7c7190c 1143 off = pcb->rcv_nxt - seqno;
GordonSin 0:0ed2a7c7190c 1144 p = inseg.p;
GordonSin 0:0ed2a7c7190c 1145 LWIP_ASSERT("inseg.p != NULL", inseg.p);
GordonSin 0:0ed2a7c7190c 1146 LWIP_ASSERT("insane offset!", (off < 0x7fff));
GordonSin 0:0ed2a7c7190c 1147 if (inseg.p->len < off) {
GordonSin 0:0ed2a7c7190c 1148 LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
GordonSin 0:0ed2a7c7190c 1149 new_tot_len = (u16_t)(inseg.p->tot_len - off);
GordonSin 0:0ed2a7c7190c 1150 while (p->len < off) {
GordonSin 0:0ed2a7c7190c 1151 off -= p->len;
GordonSin 0:0ed2a7c7190c 1152 /* KJM following line changed (with addition of new_tot_len var)
GordonSin 0:0ed2a7c7190c 1153 to fix bug #9076
GordonSin 0:0ed2a7c7190c 1154 inseg.p->tot_len -= p->len; */
GordonSin 0:0ed2a7c7190c 1155 p->tot_len = new_tot_len;
GordonSin 0:0ed2a7c7190c 1156 p->len = 0;
GordonSin 0:0ed2a7c7190c 1157 p = p->next;
GordonSin 0:0ed2a7c7190c 1158 }
GordonSin 0:0ed2a7c7190c 1159 if(pbuf_header(p, (s16_t)-off)) {
GordonSin 0:0ed2a7c7190c 1160 /* Do we need to cope with this failing? Assert for now */
GordonSin 0:0ed2a7c7190c 1161 LWIP_ASSERT("pbuf_header failed", 0);
GordonSin 0:0ed2a7c7190c 1162 }
GordonSin 0:0ed2a7c7190c 1163 } else {
GordonSin 0:0ed2a7c7190c 1164 if(pbuf_header(inseg.p, (s16_t)-off)) {
GordonSin 0:0ed2a7c7190c 1165 /* Do we need to cope with this failing? Assert for now */
GordonSin 0:0ed2a7c7190c 1166 LWIP_ASSERT("pbuf_header failed", 0);
GordonSin 0:0ed2a7c7190c 1167 }
GordonSin 0:0ed2a7c7190c 1168 }
GordonSin 0:0ed2a7c7190c 1169 inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
GordonSin 0:0ed2a7c7190c 1170 inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
GordonSin 0:0ed2a7c7190c 1171 }
GordonSin 0:0ed2a7c7190c 1172 else {
GordonSin 0:0ed2a7c7190c 1173 if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
GordonSin 0:0ed2a7c7190c 1174 /* the whole segment is < rcv_nxt */
GordonSin 0:0ed2a7c7190c 1175 /* must be a duplicate of a packet that has already been correctly handled */
GordonSin 0:0ed2a7c7190c 1176
GordonSin 0:0ed2a7c7190c 1177 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
GordonSin 0:0ed2a7c7190c 1178 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 1179 }
GordonSin 0:0ed2a7c7190c 1180 }
GordonSin 0:0ed2a7c7190c 1181
GordonSin 0:0ed2a7c7190c 1182 /* The sequence number must be within the window (above rcv_nxt
GordonSin 0:0ed2a7c7190c 1183 and below rcv_nxt + rcv_wnd) in order to be further
GordonSin 0:0ed2a7c7190c 1184 processed. */
GordonSin 0:0ed2a7c7190c 1185 if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
GordonSin 0:0ed2a7c7190c 1186 pcb->rcv_nxt + pcb->rcv_wnd - 1)){
GordonSin 0:0ed2a7c7190c 1187 if (pcb->rcv_nxt == seqno) {
GordonSin 0:0ed2a7c7190c 1188 /* The incoming segment is the next in sequence. We check if
GordonSin 0:0ed2a7c7190c 1189 we have to trim the end of the segment and update rcv_nxt
GordonSin 0:0ed2a7c7190c 1190 and pass the data to the application. */
GordonSin 0:0ed2a7c7190c 1191 tcplen = TCP_TCPLEN(&inseg);
GordonSin 0:0ed2a7c7190c 1192
GordonSin 0:0ed2a7c7190c 1193 if (tcplen > pcb->rcv_wnd) {
GordonSin 0:0ed2a7c7190c 1194 LWIP_DEBUGF(TCP_INPUT_DEBUG,
GordonSin 0:0ed2a7c7190c 1195 ("tcp_receive: other end overran receive window"
GordonSin 0:0ed2a7c7190c 1196 "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 1197 seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
GordonSin 0:0ed2a7c7190c 1198 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1199 /* Must remove the FIN from the header as we're trimming
GordonSin 0:0ed2a7c7190c 1200 * that byte of sequence-space from the packet */
GordonSin 0:0ed2a7c7190c 1201 TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
GordonSin 0:0ed2a7c7190c 1202 }
GordonSin 0:0ed2a7c7190c 1203 /* Adjust length of segment to fit in the window. */
GordonSin 0:0ed2a7c7190c 1204 inseg.len = pcb->rcv_wnd;
GordonSin 0:0ed2a7c7190c 1205 if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
GordonSin 0:0ed2a7c7190c 1206 inseg.len -= 1;
GordonSin 0:0ed2a7c7190c 1207 }
GordonSin 0:0ed2a7c7190c 1208 pbuf_realloc(inseg.p, inseg.len);
GordonSin 0:0ed2a7c7190c 1209 tcplen = TCP_TCPLEN(&inseg);
GordonSin 0:0ed2a7c7190c 1210 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
GordonSin 0:0ed2a7c7190c 1211 (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
GordonSin 0:0ed2a7c7190c 1212 }
GordonSin 0:0ed2a7c7190c 1213 #if TCP_QUEUE_OOSEQ
GordonSin 0:0ed2a7c7190c 1214 /* Received in-sequence data, adjust ooseq data if:
GordonSin 0:0ed2a7c7190c 1215 - FIN has been received or
GordonSin 0:0ed2a7c7190c 1216 - inseq overlaps with ooseq */
GordonSin 0:0ed2a7c7190c 1217 if (pcb->ooseq != NULL) {
GordonSin 0:0ed2a7c7190c 1218 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1219 LWIP_DEBUGF(TCP_INPUT_DEBUG,
GordonSin 0:0ed2a7c7190c 1220 ("tcp_receive: received in-order FIN, binning ooseq queue\n"));
GordonSin 0:0ed2a7c7190c 1221 /* Received in-order FIN means anything that was received
GordonSin 0:0ed2a7c7190c 1222 * out of order must now have been received in-order, so
GordonSin 0:0ed2a7c7190c 1223 * bin the ooseq queue */
GordonSin 0:0ed2a7c7190c 1224 while (pcb->ooseq != NULL) {
GordonSin 0:0ed2a7c7190c 1225 struct tcp_seg *old_ooseq = pcb->ooseq;
GordonSin 0:0ed2a7c7190c 1226 pcb->ooseq = pcb->ooseq->next;
GordonSin 0:0ed2a7c7190c 1227 tcp_seg_free(old_ooseq);
GordonSin 0:0ed2a7c7190c 1228 }
GordonSin 0:0ed2a7c7190c 1229 }
GordonSin 0:0ed2a7c7190c 1230 else {
GordonSin 0:0ed2a7c7190c 1231 next = pcb->ooseq;
GordonSin 0:0ed2a7c7190c 1232 /* Remove all segments on ooseq that are covered by inseg already.
GordonSin 0:0ed2a7c7190c 1233 * FIN is copied from ooseq to inseg if present. */
GordonSin 0:0ed2a7c7190c 1234 while (next &&
GordonSin 0:0ed2a7c7190c 1235 TCP_SEQ_GEQ(seqno + tcplen,
GordonSin 0:0ed2a7c7190c 1236 next->tcphdr->seqno + next->len)) {
GordonSin 0:0ed2a7c7190c 1237 /* inseg cannot have FIN here (already processed above) */
GordonSin 0:0ed2a7c7190c 1238 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
GordonSin 0:0ed2a7c7190c 1239 (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
GordonSin 0:0ed2a7c7190c 1240 TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
GordonSin 0:0ed2a7c7190c 1241 tcplen = TCP_TCPLEN(&inseg);
GordonSin 0:0ed2a7c7190c 1242 }
GordonSin 0:0ed2a7c7190c 1243 prev = next;
GordonSin 0:0ed2a7c7190c 1244 next = next->next;
GordonSin 0:0ed2a7c7190c 1245 tcp_seg_free(prev);
GordonSin 0:0ed2a7c7190c 1246 }
GordonSin 0:0ed2a7c7190c 1247 /* Now trim right side of inseg if it overlaps with the first
GordonSin 0:0ed2a7c7190c 1248 * segment on ooseq */
GordonSin 0:0ed2a7c7190c 1249 if (next &&
GordonSin 0:0ed2a7c7190c 1250 TCP_SEQ_GT(seqno + tcplen,
GordonSin 0:0ed2a7c7190c 1251 next->tcphdr->seqno)) {
GordonSin 0:0ed2a7c7190c 1252 /* inseg cannot have FIN here (already processed above) */
GordonSin 0:0ed2a7c7190c 1253 inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
GordonSin 0:0ed2a7c7190c 1254 if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
GordonSin 0:0ed2a7c7190c 1255 inseg.len -= 1;
GordonSin 0:0ed2a7c7190c 1256 }
GordonSin 0:0ed2a7c7190c 1257 pbuf_realloc(inseg.p, inseg.len);
GordonSin 0:0ed2a7c7190c 1258 tcplen = TCP_TCPLEN(&inseg);
GordonSin 0:0ed2a7c7190c 1259 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
GordonSin 0:0ed2a7c7190c 1260 (seqno + tcplen) == next->tcphdr->seqno);
GordonSin 0:0ed2a7c7190c 1261 }
GordonSin 0:0ed2a7c7190c 1262 pcb->ooseq = next;
GordonSin 0:0ed2a7c7190c 1263 }
GordonSin 0:0ed2a7c7190c 1264 }
GordonSin 0:0ed2a7c7190c 1265 #endif /* TCP_QUEUE_OOSEQ */
GordonSin 0:0ed2a7c7190c 1266
GordonSin 0:0ed2a7c7190c 1267 pcb->rcv_nxt = seqno + tcplen;
GordonSin 0:0ed2a7c7190c 1268
GordonSin 0:0ed2a7c7190c 1269 /* Update the receiver's (our) window. */
GordonSin 0:0ed2a7c7190c 1270 LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
GordonSin 0:0ed2a7c7190c 1271 pcb->rcv_wnd -= tcplen;
GordonSin 0:0ed2a7c7190c 1272
GordonSin 0:0ed2a7c7190c 1273 tcp_update_rcv_ann_wnd(pcb);
GordonSin 0:0ed2a7c7190c 1274
GordonSin 0:0ed2a7c7190c 1275 /* If there is data in the segment, we make preparations to
GordonSin 0:0ed2a7c7190c 1276 pass this up to the application. The ->recv_data variable
GordonSin 0:0ed2a7c7190c 1277 is used for holding the pbuf that goes to the
GordonSin 0:0ed2a7c7190c 1278 application. The code for reassembling out-of-sequence data
GordonSin 0:0ed2a7c7190c 1279 chains its data on this pbuf as well.
GordonSin 0:0ed2a7c7190c 1280
GordonSin 0:0ed2a7c7190c 1281 If the segment was a FIN, we set the TF_GOT_FIN flag that will
GordonSin 0:0ed2a7c7190c 1282 be used to indicate to the application that the remote side has
GordonSin 0:0ed2a7c7190c 1283 closed its end of the connection. */
GordonSin 0:0ed2a7c7190c 1284 if (inseg.p->tot_len > 0) {
GordonSin 0:0ed2a7c7190c 1285 recv_data = inseg.p;
GordonSin 0:0ed2a7c7190c 1286 /* Since this pbuf now is the responsibility of the
GordonSin 0:0ed2a7c7190c 1287 application, we delete our reference to it so that we won't
GordonSin 0:0ed2a7c7190c 1288 (mistakingly) deallocate it. */
GordonSin 0:0ed2a7c7190c 1289 inseg.p = NULL;
GordonSin 0:0ed2a7c7190c 1290 }
GordonSin 0:0ed2a7c7190c 1291 if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1292 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
GordonSin 0:0ed2a7c7190c 1293 recv_flags |= TF_GOT_FIN;
GordonSin 0:0ed2a7c7190c 1294 }
GordonSin 0:0ed2a7c7190c 1295
GordonSin 0:0ed2a7c7190c 1296 #if TCP_QUEUE_OOSEQ
GordonSin 0:0ed2a7c7190c 1297 /* We now check if we have segments on the ->ooseq queue that
GordonSin 0:0ed2a7c7190c 1298 are now in sequence. */
GordonSin 0:0ed2a7c7190c 1299 while (pcb->ooseq != NULL &&
GordonSin 0:0ed2a7c7190c 1300 pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
GordonSin 0:0ed2a7c7190c 1301
GordonSin 0:0ed2a7c7190c 1302 cseg = pcb->ooseq;
GordonSin 0:0ed2a7c7190c 1303 seqno = pcb->ooseq->tcphdr->seqno;
GordonSin 0:0ed2a7c7190c 1304
GordonSin 0:0ed2a7c7190c 1305 pcb->rcv_nxt += TCP_TCPLEN(cseg);
GordonSin 0:0ed2a7c7190c 1306 LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
GordonSin 0:0ed2a7c7190c 1307 pcb->rcv_wnd >= TCP_TCPLEN(cseg));
GordonSin 0:0ed2a7c7190c 1308 pcb->rcv_wnd -= TCP_TCPLEN(cseg);
GordonSin 0:0ed2a7c7190c 1309
GordonSin 0:0ed2a7c7190c 1310 tcp_update_rcv_ann_wnd(pcb);
GordonSin 0:0ed2a7c7190c 1311
GordonSin 0:0ed2a7c7190c 1312 if (cseg->p->tot_len > 0) {
GordonSin 0:0ed2a7c7190c 1313 /* Chain this pbuf onto the pbuf that we will pass to
GordonSin 0:0ed2a7c7190c 1314 the application. */
GordonSin 0:0ed2a7c7190c 1315 if (recv_data) {
GordonSin 0:0ed2a7c7190c 1316 pbuf_cat(recv_data, cseg->p);
GordonSin 0:0ed2a7c7190c 1317 } else {
GordonSin 0:0ed2a7c7190c 1318 recv_data = cseg->p;
GordonSin 0:0ed2a7c7190c 1319 }
GordonSin 0:0ed2a7c7190c 1320 cseg->p = NULL;
GordonSin 0:0ed2a7c7190c 1321 }
GordonSin 0:0ed2a7c7190c 1322 if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1323 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
GordonSin 0:0ed2a7c7190c 1324 recv_flags |= TF_GOT_FIN;
GordonSin 0:0ed2a7c7190c 1325 if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
GordonSin 0:0ed2a7c7190c 1326 pcb->state = CLOSE_WAIT;
GordonSin 0:0ed2a7c7190c 1327 }
GordonSin 0:0ed2a7c7190c 1328 }
GordonSin 0:0ed2a7c7190c 1329
GordonSin 0:0ed2a7c7190c 1330 pcb->ooseq = cseg->next;
GordonSin 0:0ed2a7c7190c 1331 tcp_seg_free(cseg);
GordonSin 0:0ed2a7c7190c 1332 }
GordonSin 0:0ed2a7c7190c 1333 #endif /* TCP_QUEUE_OOSEQ */
GordonSin 0:0ed2a7c7190c 1334
GordonSin 0:0ed2a7c7190c 1335
GordonSin 0:0ed2a7c7190c 1336 /* Acknowledge the segment(s). */
GordonSin 0:0ed2a7c7190c 1337 tcp_ack(pcb);
GordonSin 0:0ed2a7c7190c 1338
GordonSin 0:0ed2a7c7190c 1339 } else {
GordonSin 0:0ed2a7c7190c 1340 /* We get here if the incoming segment is out-of-sequence. */
GordonSin 0:0ed2a7c7190c 1341 tcp_send_empty_ack(pcb);
GordonSin 0:0ed2a7c7190c 1342 #if TCP_QUEUE_OOSEQ
GordonSin 0:0ed2a7c7190c 1343 /* We queue the segment on the ->ooseq queue. */
GordonSin 0:0ed2a7c7190c 1344 if (pcb->ooseq == NULL) {
GordonSin 0:0ed2a7c7190c 1345 pcb->ooseq = tcp_seg_copy(&inseg);
GordonSin 0:0ed2a7c7190c 1346 } else {
GordonSin 0:0ed2a7c7190c 1347 /* If the queue is not empty, we walk through the queue and
GordonSin 0:0ed2a7c7190c 1348 try to find a place where the sequence number of the
GordonSin 0:0ed2a7c7190c 1349 incoming segment is between the sequence numbers of the
GordonSin 0:0ed2a7c7190c 1350 previous and the next segment on the ->ooseq queue. That is
GordonSin 0:0ed2a7c7190c 1351 the place where we put the incoming segment. If needed, we
GordonSin 0:0ed2a7c7190c 1352 trim the second edges of the previous and the incoming
GordonSin 0:0ed2a7c7190c 1353 segment so that it will fit into the sequence.
GordonSin 0:0ed2a7c7190c 1354
GordonSin 0:0ed2a7c7190c 1355 If the incoming segment has the same sequence number as a
GordonSin 0:0ed2a7c7190c 1356 segment on the ->ooseq queue, we discard the segment that
GordonSin 0:0ed2a7c7190c 1357 contains less data. */
GordonSin 0:0ed2a7c7190c 1358
GordonSin 0:0ed2a7c7190c 1359 prev = NULL;
GordonSin 0:0ed2a7c7190c 1360 for(next = pcb->ooseq; next != NULL; next = next->next) {
GordonSin 0:0ed2a7c7190c 1361 if (seqno == next->tcphdr->seqno) {
GordonSin 0:0ed2a7c7190c 1362 /* The sequence number of the incoming segment is the
GordonSin 0:0ed2a7c7190c 1363 same as the sequence number of the segment on
GordonSin 0:0ed2a7c7190c 1364 ->ooseq. We check the lengths to see which one to
GordonSin 0:0ed2a7c7190c 1365 discard. */
GordonSin 0:0ed2a7c7190c 1366 if (inseg.len > next->len) {
GordonSin 0:0ed2a7c7190c 1367 /* The incoming segment is larger than the old
GordonSin 0:0ed2a7c7190c 1368 segment. We replace some segments with the new
GordonSin 0:0ed2a7c7190c 1369 one. */
GordonSin 0:0ed2a7c7190c 1370 cseg = tcp_seg_copy(&inseg);
GordonSin 0:0ed2a7c7190c 1371 if (cseg != NULL) {
GordonSin 0:0ed2a7c7190c 1372 if (prev != NULL) {
GordonSin 0:0ed2a7c7190c 1373 prev->next = cseg;
GordonSin 0:0ed2a7c7190c 1374 } else {
GordonSin 0:0ed2a7c7190c 1375 pcb->ooseq = cseg;
GordonSin 0:0ed2a7c7190c 1376 }
GordonSin 0:0ed2a7c7190c 1377 tcp_oos_insert_segment(cseg, next);
GordonSin 0:0ed2a7c7190c 1378 }
GordonSin 0:0ed2a7c7190c 1379 break;
GordonSin 0:0ed2a7c7190c 1380 } else {
GordonSin 0:0ed2a7c7190c 1381 /* Either the lenghts are the same or the incoming
GordonSin 0:0ed2a7c7190c 1382 segment was smaller than the old one; in either
GordonSin 0:0ed2a7c7190c 1383 case, we ditch the incoming segment. */
GordonSin 0:0ed2a7c7190c 1384 break;
GordonSin 0:0ed2a7c7190c 1385 }
GordonSin 0:0ed2a7c7190c 1386 } else {
GordonSin 0:0ed2a7c7190c 1387 if (prev == NULL) {
GordonSin 0:0ed2a7c7190c 1388 if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
GordonSin 0:0ed2a7c7190c 1389 /* The sequence number of the incoming segment is lower
GordonSin 0:0ed2a7c7190c 1390 than the sequence number of the first segment on the
GordonSin 0:0ed2a7c7190c 1391 queue. We put the incoming segment first on the
GordonSin 0:0ed2a7c7190c 1392 queue. */
GordonSin 0:0ed2a7c7190c 1393 cseg = tcp_seg_copy(&inseg);
GordonSin 0:0ed2a7c7190c 1394 if (cseg != NULL) {
GordonSin 0:0ed2a7c7190c 1395 pcb->ooseq = cseg;
GordonSin 0:0ed2a7c7190c 1396 tcp_oos_insert_segment(cseg, next);
GordonSin 0:0ed2a7c7190c 1397 }
GordonSin 0:0ed2a7c7190c 1398 break;
GordonSin 0:0ed2a7c7190c 1399 }
GordonSin 0:0ed2a7c7190c 1400 } else {
GordonSin 0:0ed2a7c7190c 1401 /*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
GordonSin 0:0ed2a7c7190c 1402 TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
GordonSin 0:0ed2a7c7190c 1403 if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
GordonSin 0:0ed2a7c7190c 1404 /* The sequence number of the incoming segment is in
GordonSin 0:0ed2a7c7190c 1405 between the sequence numbers of the previous and
GordonSin 0:0ed2a7c7190c 1406 the next segment on ->ooseq. We trim trim the previous
GordonSin 0:0ed2a7c7190c 1407 segment, delete next segments that included in received segment
GordonSin 0:0ed2a7c7190c 1408 and trim received, if needed. */
GordonSin 0:0ed2a7c7190c 1409 cseg = tcp_seg_copy(&inseg);
GordonSin 0:0ed2a7c7190c 1410 if (cseg != NULL) {
GordonSin 0:0ed2a7c7190c 1411 if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
GordonSin 0:0ed2a7c7190c 1412 /* We need to trim the prev segment. */
GordonSin 0:0ed2a7c7190c 1413 prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
GordonSin 0:0ed2a7c7190c 1414 pbuf_realloc(prev->p, prev->len);
GordonSin 0:0ed2a7c7190c 1415 }
GordonSin 0:0ed2a7c7190c 1416 prev->next = cseg;
GordonSin 0:0ed2a7c7190c 1417 tcp_oos_insert_segment(cseg, next);
GordonSin 0:0ed2a7c7190c 1418 }
GordonSin 0:0ed2a7c7190c 1419 break;
GordonSin 0:0ed2a7c7190c 1420 }
GordonSin 0:0ed2a7c7190c 1421 }
GordonSin 0:0ed2a7c7190c 1422 /* If the "next" segment is the last segment on the
GordonSin 0:0ed2a7c7190c 1423 ooseq queue, we add the incoming segment to the end
GordonSin 0:0ed2a7c7190c 1424 of the list. */
GordonSin 0:0ed2a7c7190c 1425 if (next->next == NULL &&
GordonSin 0:0ed2a7c7190c 1426 TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
GordonSin 0:0ed2a7c7190c 1427 if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1428 /* segment "next" already contains all data */
GordonSin 0:0ed2a7c7190c 1429 break;
GordonSin 0:0ed2a7c7190c 1430 }
GordonSin 0:0ed2a7c7190c 1431 next->next = tcp_seg_copy(&inseg);
GordonSin 0:0ed2a7c7190c 1432 if (next->next != NULL) {
GordonSin 0:0ed2a7c7190c 1433 if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
GordonSin 0:0ed2a7c7190c 1434 /* We need to trim the last segment. */
GordonSin 0:0ed2a7c7190c 1435 next->len = (u16_t)(seqno - next->tcphdr->seqno);
GordonSin 0:0ed2a7c7190c 1436 pbuf_realloc(next->p, next->len);
GordonSin 0:0ed2a7c7190c 1437 }
GordonSin 0:0ed2a7c7190c 1438 /* check if the remote side overruns our receive window */
GordonSin 0:0ed2a7c7190c 1439 if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
GordonSin 0:0ed2a7c7190c 1440 LWIP_DEBUGF(TCP_INPUT_DEBUG,
GordonSin 0:0ed2a7c7190c 1441 ("tcp_receive: other end overran receive window"
GordonSin 0:0ed2a7c7190c 1442 "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
GordonSin 0:0ed2a7c7190c 1443 seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
GordonSin 0:0ed2a7c7190c 1444 if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
GordonSin 0:0ed2a7c7190c 1445 /* Must remove the FIN from the header as we're trimming
GordonSin 0:0ed2a7c7190c 1446 * that byte of sequence-space from the packet */
GordonSin 0:0ed2a7c7190c 1447 TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
GordonSin 0:0ed2a7c7190c 1448 }
GordonSin 0:0ed2a7c7190c 1449 /* Adjust length of segment to fit in the window. */
GordonSin 0:0ed2a7c7190c 1450 next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
GordonSin 0:0ed2a7c7190c 1451 pbuf_realloc(next->next->p, next->next->len);
GordonSin 0:0ed2a7c7190c 1452 tcplen = TCP_TCPLEN(next->next);
GordonSin 0:0ed2a7c7190c 1453 LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
GordonSin 0:0ed2a7c7190c 1454 (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
GordonSin 0:0ed2a7c7190c 1455 }
GordonSin 0:0ed2a7c7190c 1456 }
GordonSin 0:0ed2a7c7190c 1457 break;
GordonSin 0:0ed2a7c7190c 1458 }
GordonSin 0:0ed2a7c7190c 1459 }
GordonSin 0:0ed2a7c7190c 1460 prev = next;
GordonSin 0:0ed2a7c7190c 1461 }
GordonSin 0:0ed2a7c7190c 1462 }
GordonSin 0:0ed2a7c7190c 1463 #endif /* TCP_QUEUE_OOSEQ */
GordonSin 0:0ed2a7c7190c 1464
GordonSin 0:0ed2a7c7190c 1465 }
GordonSin 0:0ed2a7c7190c 1466 } else {
GordonSin 0:0ed2a7c7190c 1467 /* The incoming segment is not withing the window. */
GordonSin 0:0ed2a7c7190c 1468 tcp_send_empty_ack(pcb);
GordonSin 0:0ed2a7c7190c 1469 }
GordonSin 0:0ed2a7c7190c 1470 } else {
GordonSin 0:0ed2a7c7190c 1471 /* Segments with length 0 is taken care of here. Segments that
GordonSin 0:0ed2a7c7190c 1472 fall out of the window are ACKed. */
GordonSin 0:0ed2a7c7190c 1473 /*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) ||
GordonSin 0:0ed2a7c7190c 1474 TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
GordonSin 0:0ed2a7c7190c 1475 if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
GordonSin 0:0ed2a7c7190c 1476 tcp_ack_now(pcb);
GordonSin 0:0ed2a7c7190c 1477 }
GordonSin 0:0ed2a7c7190c 1478 }
GordonSin 0:0ed2a7c7190c 1479 }
GordonSin 0:0ed2a7c7190c 1480
GordonSin 0:0ed2a7c7190c 1481 /**
GordonSin 0:0ed2a7c7190c 1482 * Parses the options contained in the incoming segment.
GordonSin 0:0ed2a7c7190c 1483 *
GordonSin 0:0ed2a7c7190c 1484 * Called from tcp_listen_input() and tcp_process().
GordonSin 0:0ed2a7c7190c 1485 * Currently, only the MSS option is supported!
GordonSin 0:0ed2a7c7190c 1486 *
GordonSin 0:0ed2a7c7190c 1487 * @param pcb the tcp_pcb for which a segment arrived
GordonSin 0:0ed2a7c7190c 1488 */
GordonSin 0:0ed2a7c7190c 1489 static void
GordonSin 0:0ed2a7c7190c 1490 tcp_parseopt(struct tcp_pcb *pcb)
GordonSin 0:0ed2a7c7190c 1491 {
GordonSin 0:0ed2a7c7190c 1492 u16_t c, max_c;
GordonSin 0:0ed2a7c7190c 1493 u16_t mss;
GordonSin 0:0ed2a7c7190c 1494 u8_t *opts, opt;
GordonSin 0:0ed2a7c7190c 1495 #if LWIP_TCP_TIMESTAMPS
GordonSin 0:0ed2a7c7190c 1496 u32_t tsval;
GordonSin 0:0ed2a7c7190c 1497 #endif
GordonSin 0:0ed2a7c7190c 1498
GordonSin 0:0ed2a7c7190c 1499 opts = (u8_t *)tcphdr + TCP_HLEN;
GordonSin 0:0ed2a7c7190c 1500
GordonSin 0:0ed2a7c7190c 1501 /* Parse the TCP MSS option, if present. */
GordonSin 0:0ed2a7c7190c 1502 if(TCPH_HDRLEN(tcphdr) > 0x5) {
GordonSin 0:0ed2a7c7190c 1503 max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
GordonSin 0:0ed2a7c7190c 1504 for (c = 0; c < max_c; ) {
GordonSin 0:0ed2a7c7190c 1505 opt = opts[c];
GordonSin 0:0ed2a7c7190c 1506 switch (opt) {
GordonSin 0:0ed2a7c7190c 1507 case 0x00:
GordonSin 0:0ed2a7c7190c 1508 /* End of options. */
GordonSin 0:0ed2a7c7190c 1509 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
GordonSin 0:0ed2a7c7190c 1510 return;
GordonSin 0:0ed2a7c7190c 1511 case 0x01:
GordonSin 0:0ed2a7c7190c 1512 /* NOP option. */
GordonSin 0:0ed2a7c7190c 1513 ++c;
GordonSin 0:0ed2a7c7190c 1514 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
GordonSin 0:0ed2a7c7190c 1515 break;
GordonSin 0:0ed2a7c7190c 1516 case 0x02:
GordonSin 0:0ed2a7c7190c 1517 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
GordonSin 0:0ed2a7c7190c 1518 if (opts[c + 1] != 0x04 || c + 0x04 > max_c) {
GordonSin 0:0ed2a7c7190c 1519 /* Bad length */
GordonSin 0:0ed2a7c7190c 1520 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
GordonSin 0:0ed2a7c7190c 1521 return;
GordonSin 0:0ed2a7c7190c 1522 }
GordonSin 0:0ed2a7c7190c 1523 /* An MSS option with the right option length. */
GordonSin 0:0ed2a7c7190c 1524 mss = (opts[c + 2] << 8) | opts[c + 3];
GordonSin 0:0ed2a7c7190c 1525 /* Limit the mss to the configured TCP_MSS and prevent division by zero */
GordonSin 0:0ed2a7c7190c 1526 pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss;
GordonSin 0:0ed2a7c7190c 1527 /* Advance to next option */
GordonSin 0:0ed2a7c7190c 1528 c += 0x04;
GordonSin 0:0ed2a7c7190c 1529 break;
GordonSin 0:0ed2a7c7190c 1530 #if LWIP_TCP_TIMESTAMPS
GordonSin 0:0ed2a7c7190c 1531 case 0x08:
GordonSin 0:0ed2a7c7190c 1532 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
GordonSin 0:0ed2a7c7190c 1533 if (opts[c + 1] != 0x0A || c + 0x0A > max_c) {
GordonSin 0:0ed2a7c7190c 1534 /* Bad length */
GordonSin 0:0ed2a7c7190c 1535 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
GordonSin 0:0ed2a7c7190c 1536 return;
GordonSin 0:0ed2a7c7190c 1537 }
GordonSin 0:0ed2a7c7190c 1538 /* TCP timestamp option with valid length */
GordonSin 0:0ed2a7c7190c 1539 tsval = (opts[c+2]) | (opts[c+3] << 8) |
GordonSin 0:0ed2a7c7190c 1540 (opts[c+4] << 16) | (opts[c+5] << 24);
GordonSin 0:0ed2a7c7190c 1541 if (flags & TCP_SYN) {
GordonSin 0:0ed2a7c7190c 1542 pcb->ts_recent = ntohl(tsval);
GordonSin 0:0ed2a7c7190c 1543 pcb->flags |= TF_TIMESTAMP;
GordonSin 0:0ed2a7c7190c 1544 } else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
GordonSin 0:0ed2a7c7190c 1545 pcb->ts_recent = ntohl(tsval);
GordonSin 0:0ed2a7c7190c 1546 }
GordonSin 0:0ed2a7c7190c 1547 /* Advance to next option */
GordonSin 0:0ed2a7c7190c 1548 c += 0x0A;
GordonSin 0:0ed2a7c7190c 1549 break;
GordonSin 0:0ed2a7c7190c 1550 #endif
GordonSin 0:0ed2a7c7190c 1551 default:
GordonSin 0:0ed2a7c7190c 1552 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
GordonSin 0:0ed2a7c7190c 1553 if (opts[c + 1] == 0) {
GordonSin 0:0ed2a7c7190c 1554 LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
GordonSin 0:0ed2a7c7190c 1555 /* If the length field is zero, the options are malformed
GordonSin 0:0ed2a7c7190c 1556 and we don't process them further. */
GordonSin 0:0ed2a7c7190c 1557 return;
GordonSin 0:0ed2a7c7190c 1558 }
GordonSin 0:0ed2a7c7190c 1559 /* All other options have a length field, so that we easily
GordonSin 0:0ed2a7c7190c 1560 can skip past them. */
GordonSin 0:0ed2a7c7190c 1561 c += opts[c + 1];
GordonSin 0:0ed2a7c7190c 1562 }
GordonSin 0:0ed2a7c7190c 1563 }
GordonSin 0:0ed2a7c7190c 1564 }
GordonSin 0:0ed2a7c7190c 1565 }
GordonSin 0:0ed2a7c7190c 1566
GordonSin 0:0ed2a7c7190c 1567 #endif /* LWIP_TCP */