My fork of the HTTPServer (working)
Core/lwIP/core/tcp_in.c@1:284f2df30cf9, 2012-11-20 (annotated)
- Committer:
- screamer
- Date:
- Tue Nov 20 12:18:53 2012 +0000
- Revision:
- 1:284f2df30cf9
- Parent:
- 0:7a64fbb4069d
local changes
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
screamer | 0:7a64fbb4069d | 1 | /** |
screamer | 0:7a64fbb4069d | 2 | * @file |
screamer | 0:7a64fbb4069d | 3 | * Transmission Control Protocol, incoming traffic |
screamer | 0:7a64fbb4069d | 4 | * |
screamer | 0:7a64fbb4069d | 5 | * The input processing functions of the TCP layer. |
screamer | 0:7a64fbb4069d | 6 | * |
screamer | 0:7a64fbb4069d | 7 | * These functions are generally called in the order (ip_input() ->) |
screamer | 0:7a64fbb4069d | 8 | * tcp_input() -> * tcp_process() -> tcp_receive() (-> application). |
screamer | 0:7a64fbb4069d | 9 | * |
screamer | 0:7a64fbb4069d | 10 | */ |
screamer | 0:7a64fbb4069d | 11 | |
screamer | 0:7a64fbb4069d | 12 | /* |
screamer | 0:7a64fbb4069d | 13 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
screamer | 0:7a64fbb4069d | 14 | * All rights reserved. |
screamer | 0:7a64fbb4069d | 15 | * |
screamer | 0:7a64fbb4069d | 16 | * Redistribution and use in source and binary forms, with or without modification, |
screamer | 0:7a64fbb4069d | 17 | * are permitted provided that the following conditions are met: |
screamer | 0:7a64fbb4069d | 18 | * |
screamer | 0:7a64fbb4069d | 19 | * 1. Redistributions of source code must retain the above copyright notice, |
screamer | 0:7a64fbb4069d | 20 | * this list of conditions and the following disclaimer. |
screamer | 0:7a64fbb4069d | 21 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
screamer | 0:7a64fbb4069d | 22 | * this list of conditions and the following disclaimer in the documentation |
screamer | 0:7a64fbb4069d | 23 | * and/or other materials provided with the distribution. |
screamer | 0:7a64fbb4069d | 24 | * 3. The name of the author may not be used to endorse or promote products |
screamer | 0:7a64fbb4069d | 25 | * derived from this software without specific prior written permission. |
screamer | 0:7a64fbb4069d | 26 | * |
screamer | 0:7a64fbb4069d | 27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
screamer | 0:7a64fbb4069d | 28 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
screamer | 0:7a64fbb4069d | 29 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
screamer | 0:7a64fbb4069d | 30 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
screamer | 0:7a64fbb4069d | 31 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
screamer | 0:7a64fbb4069d | 32 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
screamer | 0:7a64fbb4069d | 33 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
screamer | 0:7a64fbb4069d | 34 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
screamer | 0:7a64fbb4069d | 35 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
screamer | 0:7a64fbb4069d | 36 | * OF SUCH DAMAGE. |
screamer | 0:7a64fbb4069d | 37 | * |
screamer | 0:7a64fbb4069d | 38 | * This file is part of the lwIP TCP/IP stack. |
screamer | 0:7a64fbb4069d | 39 | * |
screamer | 0:7a64fbb4069d | 40 | * Author: Adam Dunkels <adam@sics.se> |
screamer | 0:7a64fbb4069d | 41 | * |
screamer | 0:7a64fbb4069d | 42 | */ |
screamer | 0:7a64fbb4069d | 43 | |
screamer | 0:7a64fbb4069d | 44 | #include "lwip/opt.h" |
screamer | 0:7a64fbb4069d | 45 | |
screamer | 0:7a64fbb4069d | 46 | #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ |
screamer | 0:7a64fbb4069d | 47 | |
screamer | 0:7a64fbb4069d | 48 | #include "lwip/tcp.h" |
screamer | 0:7a64fbb4069d | 49 | #include "lwip/def.h" |
screamer | 0:7a64fbb4069d | 50 | #include "lwip/ip_addr.h" |
screamer | 0:7a64fbb4069d | 51 | #include "lwip/netif.h" |
screamer | 0:7a64fbb4069d | 52 | #include "lwip/mem.h" |
screamer | 0:7a64fbb4069d | 53 | #include "lwip/memp.h" |
screamer | 0:7a64fbb4069d | 54 | #include "lwip/inet.h" |
screamer | 0:7a64fbb4069d | 55 | #include "lwip/inet_chksum.h" |
screamer | 0:7a64fbb4069d | 56 | #include "lwip/stats.h" |
screamer | 0:7a64fbb4069d | 57 | #include "lwip/snmp.h" |
screamer | 0:7a64fbb4069d | 58 | #include "arch/perf.h" |
screamer | 0:7a64fbb4069d | 59 | |
screamer | 0:7a64fbb4069d | 60 | /* These variables are global to all functions involved in the input |
screamer | 0:7a64fbb4069d | 61 | processing of TCP segments. They are set by the tcp_input() |
screamer | 0:7a64fbb4069d | 62 | function. */ |
screamer | 0:7a64fbb4069d | 63 | static struct tcp_seg inseg; |
screamer | 0:7a64fbb4069d | 64 | static struct tcp_hdr *tcphdr; |
screamer | 0:7a64fbb4069d | 65 | static struct ip_hdr *iphdr; |
screamer | 0:7a64fbb4069d | 66 | static u32_t seqno, ackno; |
screamer | 0:7a64fbb4069d | 67 | static u8_t flags; |
screamer | 0:7a64fbb4069d | 68 | static u16_t tcplen; |
screamer | 0:7a64fbb4069d | 69 | |
screamer | 0:7a64fbb4069d | 70 | static u8_t recv_flags; |
screamer | 0:7a64fbb4069d | 71 | static struct pbuf *recv_data; |
screamer | 0:7a64fbb4069d | 72 | |
screamer | 0:7a64fbb4069d | 73 | struct tcp_pcb *tcp_input_pcb; |
screamer | 0:7a64fbb4069d | 74 | |
screamer | 0:7a64fbb4069d | 75 | /* Forward declarations. */ |
screamer | 0:7a64fbb4069d | 76 | static err_t tcp_process(struct tcp_pcb *pcb); |
screamer | 0:7a64fbb4069d | 77 | static u8_t tcp_receive(struct tcp_pcb *pcb); |
screamer | 0:7a64fbb4069d | 78 | static void tcp_parseopt(struct tcp_pcb *pcb); |
screamer | 0:7a64fbb4069d | 79 | |
screamer | 0:7a64fbb4069d | 80 | static err_t tcp_listen_input(struct tcp_pcb_listen *pcb); |
screamer | 0:7a64fbb4069d | 81 | static err_t tcp_timewait_input(struct tcp_pcb *pcb); |
screamer | 0:7a64fbb4069d | 82 | |
screamer | 0:7a64fbb4069d | 83 | /** |
screamer | 0:7a64fbb4069d | 84 | * The initial input processing of TCP. It verifies the TCP header, demultiplexes |
screamer | 0:7a64fbb4069d | 85 | * the segment between the PCBs and passes it on to tcp_process(), which implements |
screamer | 0:7a64fbb4069d | 86 | * the TCP finite state machine. This function is called by the IP layer (in |
screamer | 0:7a64fbb4069d | 87 | * ip_input()). |
screamer | 0:7a64fbb4069d | 88 | * |
screamer | 0:7a64fbb4069d | 89 | * @param p received TCP segment to process (p->payload pointing to the IP header) |
screamer | 0:7a64fbb4069d | 90 | * @param inp network interface on which this segment was received |
screamer | 0:7a64fbb4069d | 91 | */ |
screamer | 0:7a64fbb4069d | 92 | void |
screamer | 0:7a64fbb4069d | 93 | tcp_input(struct pbuf *p, struct netif *inp) |
screamer | 0:7a64fbb4069d | 94 | { |
screamer | 0:7a64fbb4069d | 95 | struct tcp_pcb *pcb, *prev; |
screamer | 0:7a64fbb4069d | 96 | struct tcp_pcb_listen *lpcb; |
screamer | 0:7a64fbb4069d | 97 | u8_t hdrlen; |
screamer | 0:7a64fbb4069d | 98 | err_t err; |
screamer | 0:7a64fbb4069d | 99 | |
screamer | 0:7a64fbb4069d | 100 | PERF_START; |
screamer | 0:7a64fbb4069d | 101 | |
screamer | 0:7a64fbb4069d | 102 | TCP_STATS_INC(tcp.recv); |
screamer | 0:7a64fbb4069d | 103 | snmp_inc_tcpinsegs(); |
screamer | 0:7a64fbb4069d | 104 | |
screamer | 0:7a64fbb4069d | 105 | iphdr = (struct ip_hdr *)(p->payload); |
screamer | 0:7a64fbb4069d | 106 | tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4); |
screamer | 0:7a64fbb4069d | 107 | |
screamer | 0:7a64fbb4069d | 108 | #if TCP_INPUT_DEBUG |
screamer | 0:7a64fbb4069d | 109 | tcp_debug_print(tcphdr); |
screamer | 0:7a64fbb4069d | 110 | #endif |
screamer | 0:7a64fbb4069d | 111 | |
screamer | 0:7a64fbb4069d | 112 | /* remove header from payload */ |
screamer | 0:7a64fbb4069d | 113 | if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) { |
screamer | 0:7a64fbb4069d | 114 | /* drop short packets */ |
screamer | 0:7a64fbb4069d | 115 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len)); |
screamer | 0:7a64fbb4069d | 116 | TCP_STATS_INC(tcp.lenerr); |
screamer | 0:7a64fbb4069d | 117 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 118 | snmp_inc_tcpinerrs(); |
screamer | 0:7a64fbb4069d | 119 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 120 | return; |
screamer | 0:7a64fbb4069d | 121 | } |
screamer | 0:7a64fbb4069d | 122 | |
screamer | 0:7a64fbb4069d | 123 | /* Don't even process incoming broadcasts/multicasts. */ |
screamer | 0:7a64fbb4069d | 124 | if (ip_addr_isbroadcast(&(iphdr->dest), inp) || |
screamer | 0:7a64fbb4069d | 125 | ip_addr_ismulticast(&(iphdr->dest))) { |
screamer | 0:7a64fbb4069d | 126 | TCP_STATS_INC(tcp.proterr); |
screamer | 0:7a64fbb4069d | 127 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 128 | snmp_inc_tcpinerrs(); |
screamer | 0:7a64fbb4069d | 129 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 130 | return; |
screamer | 0:7a64fbb4069d | 131 | } |
screamer | 0:7a64fbb4069d | 132 | |
screamer | 0:7a64fbb4069d | 133 | #if CHECKSUM_CHECK_TCP |
screamer | 0:7a64fbb4069d | 134 | /* Verify TCP checksum. */ |
screamer | 0:7a64fbb4069d | 135 | if (inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src), |
screamer | 0:7a64fbb4069d | 136 | (struct ip_addr *)&(iphdr->dest), |
screamer | 0:7a64fbb4069d | 137 | IP_PROTO_TCP, p->tot_len) != 0) { |
screamer | 0:7a64fbb4069d | 138 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n", |
screamer | 0:7a64fbb4069d | 139 | inet_chksum_pseudo(p, (struct ip_addr *)&(iphdr->src), (struct ip_addr *)&(iphdr->dest), |
screamer | 0:7a64fbb4069d | 140 | IP_PROTO_TCP, p->tot_len))); |
screamer | 0:7a64fbb4069d | 141 | #if TCP_DEBUG |
screamer | 0:7a64fbb4069d | 142 | tcp_debug_print(tcphdr); |
screamer | 0:7a64fbb4069d | 143 | #endif /* TCP_DEBUG */ |
screamer | 0:7a64fbb4069d | 144 | TCP_STATS_INC(tcp.chkerr); |
screamer | 0:7a64fbb4069d | 145 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 146 | snmp_inc_tcpinerrs(); |
screamer | 0:7a64fbb4069d | 147 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 148 | return; |
screamer | 0:7a64fbb4069d | 149 | } |
screamer | 0:7a64fbb4069d | 150 | #endif |
screamer | 0:7a64fbb4069d | 151 | |
screamer | 0:7a64fbb4069d | 152 | /* Move the payload pointer in the pbuf so that it points to the |
screamer | 0:7a64fbb4069d | 153 | TCP data instead of the TCP header. */ |
screamer | 0:7a64fbb4069d | 154 | hdrlen = TCPH_HDRLEN(tcphdr); |
screamer | 0:7a64fbb4069d | 155 | if(pbuf_header(p, -(hdrlen * 4))){ |
screamer | 0:7a64fbb4069d | 156 | /* drop short packets */ |
screamer | 0:7a64fbb4069d | 157 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n")); |
screamer | 0:7a64fbb4069d | 158 | TCP_STATS_INC(tcp.lenerr); |
screamer | 0:7a64fbb4069d | 159 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 160 | snmp_inc_tcpinerrs(); |
screamer | 0:7a64fbb4069d | 161 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 162 | return; |
screamer | 0:7a64fbb4069d | 163 | } |
screamer | 0:7a64fbb4069d | 164 | |
screamer | 0:7a64fbb4069d | 165 | /* Convert fields in TCP header to host byte order. */ |
screamer | 0:7a64fbb4069d | 166 | tcphdr->src = ntohs(tcphdr->src); |
screamer | 0:7a64fbb4069d | 167 | tcphdr->dest = ntohs(tcphdr->dest); |
screamer | 0:7a64fbb4069d | 168 | seqno = tcphdr->seqno = ntohl(tcphdr->seqno); |
screamer | 0:7a64fbb4069d | 169 | ackno = tcphdr->ackno = ntohl(tcphdr->ackno); |
screamer | 0:7a64fbb4069d | 170 | tcphdr->wnd = ntohs(tcphdr->wnd); |
screamer | 0:7a64fbb4069d | 171 | |
screamer | 0:7a64fbb4069d | 172 | flags = TCPH_FLAGS(tcphdr) & TCP_FLAGS; |
screamer | 0:7a64fbb4069d | 173 | tcplen = p->tot_len + ((flags & TCP_FIN || flags & TCP_SYN)? 1: 0); |
screamer | 0:7a64fbb4069d | 174 | |
screamer | 0:7a64fbb4069d | 175 | /* Demultiplex an incoming segment. First, we check if it is destined |
screamer | 0:7a64fbb4069d | 176 | for an active connection. */ |
screamer | 0:7a64fbb4069d | 177 | prev = (struct tcp_pcb *)(NULL); |
screamer | 0:7a64fbb4069d | 178 | |
screamer | 0:7a64fbb4069d | 179 | |
screamer | 0:7a64fbb4069d | 180 | for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { |
screamer | 0:7a64fbb4069d | 181 | LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED); |
screamer | 0:7a64fbb4069d | 182 | LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT); |
screamer | 0:7a64fbb4069d | 183 | LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN); |
screamer | 0:7a64fbb4069d | 184 | if (pcb->remote_port == tcphdr->src && |
screamer | 0:7a64fbb4069d | 185 | pcb->local_port == tcphdr->dest && |
screamer | 0:7a64fbb4069d | 186 | ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) && |
screamer | 0:7a64fbb4069d | 187 | ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) { |
screamer | 0:7a64fbb4069d | 188 | |
screamer | 0:7a64fbb4069d | 189 | /* Move this PCB to the front of the list so that subsequent |
screamer | 0:7a64fbb4069d | 190 | lookups will be faster (we exploit locality in TCP segment |
screamer | 0:7a64fbb4069d | 191 | arrivals). */ |
screamer | 0:7a64fbb4069d | 192 | LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb); |
screamer | 0:7a64fbb4069d | 193 | if (prev != NULL) { |
screamer | 0:7a64fbb4069d | 194 | prev->next = pcb->next; |
screamer | 0:7a64fbb4069d | 195 | pcb->next = tcp_active_pcbs; |
screamer | 0:7a64fbb4069d | 196 | tcp_active_pcbs = pcb; |
screamer | 0:7a64fbb4069d | 197 | } |
screamer | 0:7a64fbb4069d | 198 | LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb); |
screamer | 0:7a64fbb4069d | 199 | break; |
screamer | 0:7a64fbb4069d | 200 | } |
screamer | 0:7a64fbb4069d | 201 | prev = pcb; |
screamer | 0:7a64fbb4069d | 202 | } |
screamer | 0:7a64fbb4069d | 203 | |
screamer | 0:7a64fbb4069d | 204 | if (pcb == NULL) { |
screamer | 0:7a64fbb4069d | 205 | /* If it did not go to an active connection, we check the connections |
screamer | 0:7a64fbb4069d | 206 | in the TIME-WAIT state. */ |
screamer | 0:7a64fbb4069d | 207 | for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) { |
screamer | 0:7a64fbb4069d | 208 | LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT); |
screamer | 0:7a64fbb4069d | 209 | if (pcb->remote_port == tcphdr->src && |
screamer | 0:7a64fbb4069d | 210 | pcb->local_port == tcphdr->dest && |
screamer | 0:7a64fbb4069d | 211 | ip_addr_cmp(&(pcb->remote_ip), &(iphdr->src)) && |
screamer | 0:7a64fbb4069d | 212 | ip_addr_cmp(&(pcb->local_ip), &(iphdr->dest))) { |
screamer | 0:7a64fbb4069d | 213 | /* We don't really care enough to move this PCB to the front |
screamer | 0:7a64fbb4069d | 214 | of the list since we are not very likely to receive that |
screamer | 0:7a64fbb4069d | 215 | many segments for connections in TIME-WAIT. */ |
screamer | 0:7a64fbb4069d | 216 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n")); |
screamer | 0:7a64fbb4069d | 217 | tcp_timewait_input(pcb); |
screamer | 0:7a64fbb4069d | 218 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 219 | return; |
screamer | 0:7a64fbb4069d | 220 | } |
screamer | 0:7a64fbb4069d | 221 | } |
screamer | 0:7a64fbb4069d | 222 | |
screamer | 0:7a64fbb4069d | 223 | /* Finally, if we still did not get a match, we check all PCBs that |
screamer | 0:7a64fbb4069d | 224 | are LISTENing for incoming connections. */ |
screamer | 0:7a64fbb4069d | 225 | prev = (struct tcp_pcb *)(NULL); |
screamer | 0:7a64fbb4069d | 226 | for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) { |
screamer | 0:7a64fbb4069d | 227 | if ((ip_addr_isany(&(lpcb->local_ip)) || |
screamer | 0:7a64fbb4069d | 228 | ip_addr_cmp(&(lpcb->local_ip), &(iphdr->dest))) && |
screamer | 0:7a64fbb4069d | 229 | lpcb->local_port == tcphdr->dest) { |
screamer | 0:7a64fbb4069d | 230 | /* Move this PCB to the front of the list so that subsequent |
screamer | 0:7a64fbb4069d | 231 | lookups will be faster (we exploit locality in TCP segment |
screamer | 0:7a64fbb4069d | 232 | arrivals). */ |
screamer | 0:7a64fbb4069d | 233 | if (prev != NULL) { |
screamer | 0:7a64fbb4069d | 234 | ((struct tcp_pcb_listen *)prev)->next = lpcb->next; |
screamer | 0:7a64fbb4069d | 235 | /* our successor is the remainder of the listening list */ |
screamer | 0:7a64fbb4069d | 236 | lpcb->next = tcp_listen_pcbs.listen_pcbs; |
screamer | 0:7a64fbb4069d | 237 | /* put this listening pcb at the head of the listening list */ |
screamer | 0:7a64fbb4069d | 238 | tcp_listen_pcbs.listen_pcbs = lpcb; |
screamer | 0:7a64fbb4069d | 239 | } |
screamer | 0:7a64fbb4069d | 240 | |
screamer | 0:7a64fbb4069d | 241 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n")); |
screamer | 0:7a64fbb4069d | 242 | tcp_listen_input(lpcb); |
screamer | 0:7a64fbb4069d | 243 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 244 | return; |
screamer | 0:7a64fbb4069d | 245 | } |
screamer | 0:7a64fbb4069d | 246 | prev = (struct tcp_pcb *)lpcb; |
screamer | 0:7a64fbb4069d | 247 | } |
screamer | 0:7a64fbb4069d | 248 | } |
screamer | 0:7a64fbb4069d | 249 | |
screamer | 0:7a64fbb4069d | 250 | #if TCP_INPUT_DEBUG |
screamer | 0:7a64fbb4069d | 251 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags ")); |
screamer | 0:7a64fbb4069d | 252 | tcp_debug_print_flags(TCPH_FLAGS(tcphdr)); |
screamer | 0:7a64fbb4069d | 253 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n")); |
screamer | 0:7a64fbb4069d | 254 | #endif /* TCP_INPUT_DEBUG */ |
screamer | 0:7a64fbb4069d | 255 | |
screamer | 0:7a64fbb4069d | 256 | |
screamer | 0:7a64fbb4069d | 257 | if (pcb != NULL) { |
screamer | 0:7a64fbb4069d | 258 | /* The incoming segment belongs to a connection. */ |
screamer | 0:7a64fbb4069d | 259 | #if TCP_INPUT_DEBUG |
screamer | 0:7a64fbb4069d | 260 | #if TCP_DEBUG |
screamer | 0:7a64fbb4069d | 261 | tcp_debug_print_state(pcb->state); |
screamer | 0:7a64fbb4069d | 262 | #endif /* TCP_DEBUG */ |
screamer | 0:7a64fbb4069d | 263 | #endif /* TCP_INPUT_DEBUG */ |
screamer | 0:7a64fbb4069d | 264 | |
screamer | 0:7a64fbb4069d | 265 | /* Set up a tcp_seg structure. */ |
screamer | 0:7a64fbb4069d | 266 | inseg.next = (struct tcp_seg *)(NULL); |
screamer | 0:7a64fbb4069d | 267 | inseg.len = p->tot_len; |
screamer | 0:7a64fbb4069d | 268 | inseg.dataptr = p->payload; |
screamer | 0:7a64fbb4069d | 269 | inseg.p = p; |
screamer | 0:7a64fbb4069d | 270 | inseg.tcphdr = tcphdr; |
screamer | 0:7a64fbb4069d | 271 | |
screamer | 0:7a64fbb4069d | 272 | recv_data = (struct pbuf *)(NULL); |
screamer | 0:7a64fbb4069d | 273 | recv_flags = 0; |
screamer | 0:7a64fbb4069d | 274 | |
screamer | 0:7a64fbb4069d | 275 | /* If there is data which was previously "refused" by upper layer */ |
screamer | 0:7a64fbb4069d | 276 | if (pcb->refused_data != NULL) { |
screamer | 0:7a64fbb4069d | 277 | /* Notify again application with data previously received. */ |
screamer | 0:7a64fbb4069d | 278 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n")); |
screamer | 0:7a64fbb4069d | 279 | TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err); |
screamer | 0:7a64fbb4069d | 280 | if (err == ERR_OK) { |
screamer | 0:7a64fbb4069d | 281 | pcb->refused_data = (struct pbuf *)(NULL); |
screamer | 0:7a64fbb4069d | 282 | } else { |
screamer | 0:7a64fbb4069d | 283 | /* drop incoming packets, because pcb is "full" */ |
screamer | 0:7a64fbb4069d | 284 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n")); |
screamer | 0:7a64fbb4069d | 285 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 286 | snmp_inc_tcpinerrs(); |
screamer | 0:7a64fbb4069d | 287 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 288 | return; |
screamer | 0:7a64fbb4069d | 289 | } |
screamer | 0:7a64fbb4069d | 290 | } |
screamer | 0:7a64fbb4069d | 291 | |
screamer | 0:7a64fbb4069d | 292 | tcp_input_pcb = pcb; |
screamer | 0:7a64fbb4069d | 293 | err = tcp_process(pcb); |
screamer | 0:7a64fbb4069d | 294 | tcp_input_pcb = (struct tcp_pcb *)(NULL); |
screamer | 0:7a64fbb4069d | 295 | /* A return value of ERR_ABRT means that tcp_abort() was called |
screamer | 0:7a64fbb4069d | 296 | and that the pcb has been freed. If so, we don't do anything. */ |
screamer | 0:7a64fbb4069d | 297 | if (err != ERR_ABRT) { |
screamer | 0:7a64fbb4069d | 298 | if (recv_flags & TF_RESET) { |
screamer | 0:7a64fbb4069d | 299 | /* TF_RESET means that the connection was reset by the other |
screamer | 0:7a64fbb4069d | 300 | end. We then call the error callback to inform the |
screamer | 0:7a64fbb4069d | 301 | application that the connection is dead before we |
screamer | 0:7a64fbb4069d | 302 | deallocate the PCB. */ |
screamer | 0:7a64fbb4069d | 303 | TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST); |
screamer | 0:7a64fbb4069d | 304 | tcp_pcb_remove(&tcp_active_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 305 | memp_free(MEMP_TCP_PCB, pcb); |
screamer | 0:7a64fbb4069d | 306 | } else if (recv_flags & TF_CLOSED) { |
screamer | 0:7a64fbb4069d | 307 | /* The connection has been closed and we will deallocate the |
screamer | 0:7a64fbb4069d | 308 | PCB. */ |
screamer | 0:7a64fbb4069d | 309 | tcp_pcb_remove(&tcp_active_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 310 | memp_free(MEMP_TCP_PCB, pcb); |
screamer | 0:7a64fbb4069d | 311 | } else { |
screamer | 0:7a64fbb4069d | 312 | err = ERR_OK; |
screamer | 0:7a64fbb4069d | 313 | /* If the application has registered a "sent" function to be |
screamer | 0:7a64fbb4069d | 314 | called when new send buffer space is available, we call it |
screamer | 0:7a64fbb4069d | 315 | now. */ |
screamer | 0:7a64fbb4069d | 316 | if (pcb->acked > 0) { |
screamer | 0:7a64fbb4069d | 317 | TCP_EVENT_SENT(pcb, pcb->acked, err); |
screamer | 0:7a64fbb4069d | 318 | } |
screamer | 0:7a64fbb4069d | 319 | |
screamer | 0:7a64fbb4069d | 320 | if (recv_data != NULL) { |
screamer | 0:7a64fbb4069d | 321 | if(flags & TCP_PSH) { |
screamer | 0:7a64fbb4069d | 322 | recv_data->flags |= PBUF_FLAG_PUSH; |
screamer | 0:7a64fbb4069d | 323 | } |
screamer | 0:7a64fbb4069d | 324 | |
screamer | 0:7a64fbb4069d | 325 | /* Notify application that data has been received. */ |
screamer | 0:7a64fbb4069d | 326 | TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err); |
screamer | 0:7a64fbb4069d | 327 | |
screamer | 0:7a64fbb4069d | 328 | /* If the upper layer can't receive this data, store it */ |
screamer | 0:7a64fbb4069d | 329 | if (err != ERR_OK) { |
screamer | 0:7a64fbb4069d | 330 | pcb->refused_data = recv_data; |
screamer | 0:7a64fbb4069d | 331 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n")); |
screamer | 0:7a64fbb4069d | 332 | } |
screamer | 0:7a64fbb4069d | 333 | } |
screamer | 0:7a64fbb4069d | 334 | |
screamer | 0:7a64fbb4069d | 335 | /* If a FIN segment was received, we call the callback |
screamer | 0:7a64fbb4069d | 336 | function with a NULL buffer to indicate EOF. */ |
screamer | 0:7a64fbb4069d | 337 | if (recv_flags & TF_GOT_FIN) { |
screamer | 0:7a64fbb4069d | 338 | TCP_EVENT_RECV(pcb, (NULL), ERR_OK, err); |
screamer | 0:7a64fbb4069d | 339 | } |
screamer | 0:7a64fbb4069d | 340 | |
screamer | 0:7a64fbb4069d | 341 | /* If there were no errors, we try to send something out. */ |
screamer | 0:7a64fbb4069d | 342 | if (err == ERR_OK) { |
screamer | 0:7a64fbb4069d | 343 | tcp_output(pcb); |
screamer | 0:7a64fbb4069d | 344 | } |
screamer | 0:7a64fbb4069d | 345 | } |
screamer | 0:7a64fbb4069d | 346 | } |
screamer | 0:7a64fbb4069d | 347 | |
screamer | 0:7a64fbb4069d | 348 | |
screamer | 0:7a64fbb4069d | 349 | /* give up our reference to inseg.p */ |
screamer | 0:7a64fbb4069d | 350 | if (inseg.p != NULL) |
screamer | 0:7a64fbb4069d | 351 | { |
screamer | 0:7a64fbb4069d | 352 | pbuf_free(inseg.p); |
screamer | 0:7a64fbb4069d | 353 | inseg.p = (struct pbuf *)(NULL); |
screamer | 0:7a64fbb4069d | 354 | } |
screamer | 0:7a64fbb4069d | 355 | #if TCP_INPUT_DEBUG |
screamer | 0:7a64fbb4069d | 356 | #if TCP_DEBUG |
screamer | 0:7a64fbb4069d | 357 | tcp_debug_print_state(pcb->state); |
screamer | 0:7a64fbb4069d | 358 | #endif /* TCP_DEBUG */ |
screamer | 0:7a64fbb4069d | 359 | #endif /* TCP_INPUT_DEBUG */ |
screamer | 0:7a64fbb4069d | 360 | |
screamer | 0:7a64fbb4069d | 361 | } else { |
screamer | 0:7a64fbb4069d | 362 | |
screamer | 0:7a64fbb4069d | 363 | /* If no matching PCB was found, send a TCP RST (reset) to the |
screamer | 0:7a64fbb4069d | 364 | sender. */ |
screamer | 0:7a64fbb4069d | 365 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n")); |
screamer | 0:7a64fbb4069d | 366 | if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) { |
screamer | 0:7a64fbb4069d | 367 | TCP_STATS_INC(tcp.proterr); |
screamer | 0:7a64fbb4069d | 368 | TCP_STATS_INC(tcp.drop); |
screamer | 0:7a64fbb4069d | 369 | struct ip_addr iphdrdest; |
screamer | 0:7a64fbb4069d | 370 | iphdrdest.addr = iphdr->dest.addr; |
screamer | 0:7a64fbb4069d | 371 | struct ip_addr iphdrsrc; |
screamer | 0:7a64fbb4069d | 372 | iphdrsrc.addr = iphdr->src.addr; |
screamer | 0:7a64fbb4069d | 373 | tcp_rst(ackno, seqno + tcplen, |
screamer | 0:7a64fbb4069d | 374 | &(iphdrdest), &(iphdrsrc), |
screamer | 0:7a64fbb4069d | 375 | tcphdr->dest, tcphdr->src); |
screamer | 0:7a64fbb4069d | 376 | } |
screamer | 0:7a64fbb4069d | 377 | pbuf_free(p); |
screamer | 0:7a64fbb4069d | 378 | } |
screamer | 0:7a64fbb4069d | 379 | |
screamer | 0:7a64fbb4069d | 380 | LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane()); |
screamer | 0:7a64fbb4069d | 381 | PERF_STOP("tcp_input"); |
screamer | 0:7a64fbb4069d | 382 | } |
screamer | 0:7a64fbb4069d | 383 | |
screamer | 0:7a64fbb4069d | 384 | /** |
screamer | 0:7a64fbb4069d | 385 | * Called by tcp_input() when a segment arrives for a listening |
screamer | 0:7a64fbb4069d | 386 | * connection (from tcp_input()). |
screamer | 0:7a64fbb4069d | 387 | * |
screamer | 0:7a64fbb4069d | 388 | * @param pcb the tcp_pcb_listen for which a segment arrived |
screamer | 0:7a64fbb4069d | 389 | * @return ERR_OK if the segment was processed |
screamer | 0:7a64fbb4069d | 390 | * another err_t on error |
screamer | 0:7a64fbb4069d | 391 | * |
screamer | 0:7a64fbb4069d | 392 | * @note the return value is not (yet?) used in tcp_input() |
screamer | 0:7a64fbb4069d | 393 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
screamer | 0:7a64fbb4069d | 394 | * involved is passed as a parameter to this function |
screamer | 0:7a64fbb4069d | 395 | */ |
screamer | 0:7a64fbb4069d | 396 | static err_t |
screamer | 0:7a64fbb4069d | 397 | tcp_listen_input(struct tcp_pcb_listen *pcb) |
screamer | 0:7a64fbb4069d | 398 | { |
screamer | 0:7a64fbb4069d | 399 | struct tcp_pcb *npcb; |
screamer | 0:7a64fbb4069d | 400 | err_t rc; |
screamer | 0:7a64fbb4069d | 401 | |
screamer | 0:7a64fbb4069d | 402 | /* In the LISTEN state, we check for incoming SYN segments, |
screamer | 0:7a64fbb4069d | 403 | creates a new PCB, and responds with a SYN|ACK. */ |
screamer | 0:7a64fbb4069d | 404 | if (flags & TCP_ACK) { |
screamer | 0:7a64fbb4069d | 405 | /* For incoming segments with the ACK flag set, respond with a |
screamer | 0:7a64fbb4069d | 406 | RST. */ |
screamer | 0:7a64fbb4069d | 407 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n")); |
screamer | 0:7a64fbb4069d | 408 | struct ip_addr iphdrdest; |
screamer | 0:7a64fbb4069d | 409 | iphdrdest.addr = iphdr->dest.addr; |
screamer | 0:7a64fbb4069d | 410 | struct ip_addr iphdrsrc; |
screamer | 0:7a64fbb4069d | 411 | iphdrsrc.addr = iphdr->src.addr; |
screamer | 0:7a64fbb4069d | 412 | tcp_rst(ackno + 1, seqno + tcplen, |
screamer | 0:7a64fbb4069d | 413 | &(iphdrdest), &(iphdrsrc), |
screamer | 0:7a64fbb4069d | 414 | tcphdr->dest, tcphdr->src); |
screamer | 0:7a64fbb4069d | 415 | } else if (flags & TCP_SYN) { |
screamer | 0:7a64fbb4069d | 416 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 417 | #if TCP_LISTEN_BACKLOG |
screamer | 0:7a64fbb4069d | 418 | if (pcb->accepts_pending >= pcb->backlog) { |
screamer | 0:7a64fbb4069d | 419 | return ERR_ABRT; |
screamer | 0:7a64fbb4069d | 420 | } |
screamer | 0:7a64fbb4069d | 421 | #endif /* TCP_LISTEN_BACKLOG */ |
screamer | 0:7a64fbb4069d | 422 | npcb = tcp_alloc(pcb->prio); |
screamer | 0:7a64fbb4069d | 423 | /* If a new PCB could not be created (probably due to lack of memory), |
screamer | 0:7a64fbb4069d | 424 | we don't do anything, but rely on the sender will retransmit the |
screamer | 0:7a64fbb4069d | 425 | SYN at a time when we have more memory available. */ |
screamer | 0:7a64fbb4069d | 426 | if (npcb == NULL) { |
screamer | 0:7a64fbb4069d | 427 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n")); |
screamer | 0:7a64fbb4069d | 428 | TCP_STATS_INC(tcp.memerr); |
screamer | 0:7a64fbb4069d | 429 | return ERR_MEM; |
screamer | 0:7a64fbb4069d | 430 | } |
screamer | 0:7a64fbb4069d | 431 | #if TCP_LISTEN_BACKLOG |
screamer | 0:7a64fbb4069d | 432 | pcb->accepts_pending++; |
screamer | 0:7a64fbb4069d | 433 | #endif /* TCP_LISTEN_BACKLOG */ |
screamer | 0:7a64fbb4069d | 434 | /* Set up the new PCB. */ |
screamer | 0:7a64fbb4069d | 435 | ip_addr_set(&(npcb->local_ip), &(iphdr->dest)); |
screamer | 0:7a64fbb4069d | 436 | npcb->local_port = pcb->local_port; |
screamer | 0:7a64fbb4069d | 437 | ip_addr_set(&(npcb->remote_ip), &(iphdr->src)); |
screamer | 0:7a64fbb4069d | 438 | npcb->remote_port = tcphdr->src; |
screamer | 0:7a64fbb4069d | 439 | npcb->state = SYN_RCVD; |
screamer | 0:7a64fbb4069d | 440 | npcb->rcv_nxt = seqno + 1; |
screamer | 0:7a64fbb4069d | 441 | npcb->rcv_ann_right_edge = npcb->rcv_nxt; |
screamer | 0:7a64fbb4069d | 442 | npcb->snd_wnd = tcphdr->wnd; |
screamer | 0:7a64fbb4069d | 443 | npcb->ssthresh = npcb->snd_wnd; |
screamer | 0:7a64fbb4069d | 444 | npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */ |
screamer | 0:7a64fbb4069d | 445 | npcb->callback_arg = pcb->callback_arg; |
screamer | 0:7a64fbb4069d | 446 | #if LWIP_CALLBACK_API |
screamer | 0:7a64fbb4069d | 447 | npcb->accept = pcb->accept; |
screamer | 0:7a64fbb4069d | 448 | #endif /* LWIP_CALLBACK_API */ |
screamer | 0:7a64fbb4069d | 449 | /* inherit socket options */ |
screamer | 0:7a64fbb4069d | 450 | npcb->so_options = pcb->so_options & (SOF_DEBUG|SOF_DONTROUTE|SOF_KEEPALIVE|SOF_OOBINLINE|SOF_LINGER); |
screamer | 0:7a64fbb4069d | 451 | /* Register the new PCB so that we can begin receiving segments |
screamer | 0:7a64fbb4069d | 452 | for it. */ |
screamer | 0:7a64fbb4069d | 453 | TCP_REG(&tcp_active_pcbs, npcb); |
screamer | 0:7a64fbb4069d | 454 | |
screamer | 0:7a64fbb4069d | 455 | /* Parse any options in the SYN. */ |
screamer | 0:7a64fbb4069d | 456 | tcp_parseopt(npcb); |
screamer | 0:7a64fbb4069d | 457 | #if TCP_CALCULATE_EFF_SEND_MSS |
screamer | 0:7a64fbb4069d | 458 | npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip)); |
screamer | 0:7a64fbb4069d | 459 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */ |
screamer | 0:7a64fbb4069d | 460 | |
screamer | 0:7a64fbb4069d | 461 | snmp_inc_tcppassiveopens(); |
screamer | 0:7a64fbb4069d | 462 | |
screamer | 0:7a64fbb4069d | 463 | /* Send a SYN|ACK together with the MSS option. */ |
screamer | 0:7a64fbb4069d | 464 | rc = tcp_enqueue(npcb, NULL, 0, TCP_SYN | TCP_ACK, 0, TF_SEG_OPTS_MSS |
screamer | 0:7a64fbb4069d | 465 | #if LWIP_TCP_TIMESTAMPS |
screamer | 0:7a64fbb4069d | 466 | /* and maybe include the TIMESTAMP option */ |
screamer | 0:7a64fbb4069d | 467 | | (npcb->flags & TF_TIMESTAMP ? TF_SEG_OPTS_TS : 0) |
screamer | 0:7a64fbb4069d | 468 | #endif |
screamer | 0:7a64fbb4069d | 469 | ); |
screamer | 0:7a64fbb4069d | 470 | if (rc != ERR_OK) { |
screamer | 0:7a64fbb4069d | 471 | tcp_abandon(npcb, 0); |
screamer | 0:7a64fbb4069d | 472 | return rc; |
screamer | 0:7a64fbb4069d | 473 | } |
screamer | 0:7a64fbb4069d | 474 | return tcp_output(npcb); |
screamer | 0:7a64fbb4069d | 475 | } |
screamer | 0:7a64fbb4069d | 476 | return ERR_OK; |
screamer | 0:7a64fbb4069d | 477 | } |
screamer | 0:7a64fbb4069d | 478 | |
screamer | 0:7a64fbb4069d | 479 | /** |
screamer | 0:7a64fbb4069d | 480 | * Called by tcp_input() when a segment arrives for a connection in |
screamer | 0:7a64fbb4069d | 481 | * TIME_WAIT. |
screamer | 0:7a64fbb4069d | 482 | * |
screamer | 0:7a64fbb4069d | 483 | * @param pcb the tcp_pcb for which a segment arrived |
screamer | 0:7a64fbb4069d | 484 | * |
screamer | 0:7a64fbb4069d | 485 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
screamer | 0:7a64fbb4069d | 486 | * involved is passed as a parameter to this function |
screamer | 0:7a64fbb4069d | 487 | */ |
screamer | 0:7a64fbb4069d | 488 | static err_t |
screamer | 0:7a64fbb4069d | 489 | tcp_timewait_input(struct tcp_pcb *pcb) |
screamer | 0:7a64fbb4069d | 490 | { |
screamer | 0:7a64fbb4069d | 491 | if (TCP_SEQ_GT(seqno + tcplen, pcb->rcv_nxt)) { |
screamer | 0:7a64fbb4069d | 492 | pcb->rcv_nxt = seqno + tcplen; |
screamer | 0:7a64fbb4069d | 493 | } |
screamer | 0:7a64fbb4069d | 494 | if (tcplen > 0) { |
screamer | 0:7a64fbb4069d | 495 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 496 | } |
screamer | 0:7a64fbb4069d | 497 | return tcp_output(pcb); |
screamer | 0:7a64fbb4069d | 498 | } |
screamer | 0:7a64fbb4069d | 499 | |
screamer | 0:7a64fbb4069d | 500 | /** |
screamer | 0:7a64fbb4069d | 501 | * Implements the TCP state machine. Called by tcp_input. In some |
screamer | 0:7a64fbb4069d | 502 | * states tcp_receive() is called to receive data. The tcp_seg |
screamer | 0:7a64fbb4069d | 503 | * argument will be freed by the caller (tcp_input()) unless the |
screamer | 0:7a64fbb4069d | 504 | * recv_data pointer in the pcb is set. |
screamer | 0:7a64fbb4069d | 505 | * |
screamer | 0:7a64fbb4069d | 506 | * @param pcb the tcp_pcb for which a segment arrived |
screamer | 0:7a64fbb4069d | 507 | * |
screamer | 0:7a64fbb4069d | 508 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
screamer | 0:7a64fbb4069d | 509 | * involved is passed as a parameter to this function |
screamer | 0:7a64fbb4069d | 510 | */ |
screamer | 0:7a64fbb4069d | 511 | static err_t |
screamer | 0:7a64fbb4069d | 512 | tcp_process(struct tcp_pcb *pcb) |
screamer | 0:7a64fbb4069d | 513 | { |
screamer | 0:7a64fbb4069d | 514 | struct tcp_seg *rseg; |
screamer | 0:7a64fbb4069d | 515 | u8_t acceptable = 0; |
screamer | 0:7a64fbb4069d | 516 | err_t err; |
screamer | 0:7a64fbb4069d | 517 | u8_t accepted_inseq; |
screamer | 0:7a64fbb4069d | 518 | |
screamer | 0:7a64fbb4069d | 519 | err = ERR_OK; |
screamer | 0:7a64fbb4069d | 520 | |
screamer | 0:7a64fbb4069d | 521 | /* Process incoming RST segments. */ |
screamer | 0:7a64fbb4069d | 522 | if (flags & TCP_RST) { |
screamer | 0:7a64fbb4069d | 523 | /* First, determine if the reset is acceptable. */ |
screamer | 0:7a64fbb4069d | 524 | if (pcb->state == SYN_SENT) { |
screamer | 0:7a64fbb4069d | 525 | if (ackno == pcb->snd_nxt) { |
screamer | 0:7a64fbb4069d | 526 | acceptable = 1; |
screamer | 0:7a64fbb4069d | 527 | } |
screamer | 0:7a64fbb4069d | 528 | } else { |
screamer | 0:7a64fbb4069d | 529 | if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, |
screamer | 0:7a64fbb4069d | 530 | pcb->rcv_nxt+pcb->rcv_wnd)) { |
screamer | 0:7a64fbb4069d | 531 | acceptable = 1; |
screamer | 0:7a64fbb4069d | 532 | } |
screamer | 0:7a64fbb4069d | 533 | } |
screamer | 0:7a64fbb4069d | 534 | |
screamer | 0:7a64fbb4069d | 535 | if (acceptable) { |
screamer | 0:7a64fbb4069d | 536 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n")); |
screamer | 0:7a64fbb4069d | 537 | LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED); |
screamer | 0:7a64fbb4069d | 538 | recv_flags = TF_RESET; |
screamer | 0:7a64fbb4069d | 539 | pcb->flags &= ~TF_ACK_DELAY; |
screamer | 0:7a64fbb4069d | 540 | return ERR_RST; |
screamer | 0:7a64fbb4069d | 541 | } else { |
screamer | 0:7a64fbb4069d | 542 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 543 | seqno, pcb->rcv_nxt)); |
screamer | 0:7a64fbb4069d | 544 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 545 | seqno, pcb->rcv_nxt)); |
screamer | 0:7a64fbb4069d | 546 | return ERR_OK; |
screamer | 0:7a64fbb4069d | 547 | } |
screamer | 0:7a64fbb4069d | 548 | } |
screamer | 0:7a64fbb4069d | 549 | |
screamer | 0:7a64fbb4069d | 550 | if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) { |
screamer | 0:7a64fbb4069d | 551 | /* Cope with new connection attempt after remote end crashed */ |
screamer | 0:7a64fbb4069d | 552 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 553 | return ERR_OK; |
screamer | 0:7a64fbb4069d | 554 | } |
screamer | 0:7a64fbb4069d | 555 | |
screamer | 0:7a64fbb4069d | 556 | /* Update the PCB (in)activity timer. */ |
screamer | 0:7a64fbb4069d | 557 | pcb->tmr = tcp_ticks; |
screamer | 0:7a64fbb4069d | 558 | pcb->keep_cnt_sent = 0; |
screamer | 0:7a64fbb4069d | 559 | |
screamer | 0:7a64fbb4069d | 560 | tcp_parseopt(pcb); |
screamer | 0:7a64fbb4069d | 561 | |
screamer | 0:7a64fbb4069d | 562 | /* Do different things depending on the TCP state. */ |
screamer | 0:7a64fbb4069d | 563 | switch (pcb->state) { |
screamer | 0:7a64fbb4069d | 564 | case SYN_SENT: |
screamer | 0:7a64fbb4069d | 565 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno, |
screamer | 0:7a64fbb4069d | 566 | pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno))); |
screamer | 0:7a64fbb4069d | 567 | /* received SYN ACK with expected sequence number? */ |
screamer | 0:7a64fbb4069d | 568 | if ((flags & TCP_ACK) && (flags & TCP_SYN) |
screamer | 0:7a64fbb4069d | 569 | && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) { |
screamer | 0:7a64fbb4069d | 570 | pcb->snd_buf++; |
screamer | 0:7a64fbb4069d | 571 | pcb->rcv_nxt = seqno + 1; |
screamer | 0:7a64fbb4069d | 572 | pcb->rcv_ann_right_edge = pcb->rcv_nxt; |
screamer | 0:7a64fbb4069d | 573 | pcb->lastack = ackno; |
screamer | 0:7a64fbb4069d | 574 | pcb->snd_wnd = tcphdr->wnd; |
screamer | 0:7a64fbb4069d | 575 | pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */ |
screamer | 0:7a64fbb4069d | 576 | pcb->state = ESTABLISHED; |
screamer | 0:7a64fbb4069d | 577 | |
screamer | 0:7a64fbb4069d | 578 | #if TCP_CALCULATE_EFF_SEND_MSS |
screamer | 0:7a64fbb4069d | 579 | pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip)); |
screamer | 0:7a64fbb4069d | 580 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */ |
screamer | 0:7a64fbb4069d | 581 | |
screamer | 0:7a64fbb4069d | 582 | /* Set ssthresh again after changing pcb->mss (already set in tcp_connect |
screamer | 0:7a64fbb4069d | 583 | * but for the default value of pcb->mss) */ |
screamer | 0:7a64fbb4069d | 584 | pcb->ssthresh = pcb->mss * 10; |
screamer | 0:7a64fbb4069d | 585 | |
screamer | 0:7a64fbb4069d | 586 | pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss); |
screamer | 0:7a64fbb4069d | 587 | LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0)); |
screamer | 0:7a64fbb4069d | 588 | --pcb->snd_queuelen; |
screamer | 0:7a64fbb4069d | 589 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen)); |
screamer | 0:7a64fbb4069d | 590 | rseg = pcb->unacked; |
screamer | 0:7a64fbb4069d | 591 | pcb->unacked = rseg->next; |
screamer | 0:7a64fbb4069d | 592 | |
screamer | 0:7a64fbb4069d | 593 | /* If there's nothing left to acknowledge, stop the retransmit |
screamer | 0:7a64fbb4069d | 594 | timer, otherwise reset it to start again */ |
screamer | 0:7a64fbb4069d | 595 | if(pcb->unacked == NULL) |
screamer | 0:7a64fbb4069d | 596 | pcb->rtime = -1; |
screamer | 0:7a64fbb4069d | 597 | else { |
screamer | 0:7a64fbb4069d | 598 | pcb->rtime = 0; |
screamer | 0:7a64fbb4069d | 599 | pcb->nrtx = 0; |
screamer | 0:7a64fbb4069d | 600 | } |
screamer | 0:7a64fbb4069d | 601 | |
screamer | 0:7a64fbb4069d | 602 | tcp_seg_free(rseg); |
screamer | 0:7a64fbb4069d | 603 | |
screamer | 0:7a64fbb4069d | 604 | /* Call the user specified function to call when sucessfully |
screamer | 0:7a64fbb4069d | 605 | * connected. */ |
screamer | 0:7a64fbb4069d | 606 | TCP_EVENT_CONNECTED(pcb, ERR_OK, err); |
screamer | 0:7a64fbb4069d | 607 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 608 | } |
screamer | 0:7a64fbb4069d | 609 | /* received ACK? possibly a half-open connection */ |
screamer | 0:7a64fbb4069d | 610 | else if (flags & TCP_ACK) { |
screamer | 0:7a64fbb4069d | 611 | /* send a RST to bring the other side in a non-synchronized state. */ |
screamer | 0:7a64fbb4069d | 612 | struct ip_addr iphdrdest; |
screamer | 0:7a64fbb4069d | 613 | iphdrdest.addr = iphdr->dest.addr; |
screamer | 0:7a64fbb4069d | 614 | struct ip_addr iphdrsrc; |
screamer | 0:7a64fbb4069d | 615 | iphdrsrc.addr = iphdr->src.addr; |
screamer | 0:7a64fbb4069d | 616 | tcp_rst(ackno, seqno + tcplen, &(iphdrdest), &(iphdrsrc), |
screamer | 0:7a64fbb4069d | 617 | tcphdr->dest, tcphdr->src); |
screamer | 0:7a64fbb4069d | 618 | } |
screamer | 0:7a64fbb4069d | 619 | break; |
screamer | 0:7a64fbb4069d | 620 | case SYN_RCVD: |
screamer | 0:7a64fbb4069d | 621 | if (flags & TCP_ACK) { |
screamer | 0:7a64fbb4069d | 622 | /* expected ACK number? */ |
screamer | 0:7a64fbb4069d | 623 | if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) { |
screamer | 0:7a64fbb4069d | 624 | u16_t old_cwnd; |
screamer | 0:7a64fbb4069d | 625 | pcb->state = ESTABLISHED; |
screamer | 0:7a64fbb4069d | 626 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 627 | #if LWIP_CALLBACK_API |
screamer | 0:7a64fbb4069d | 628 | LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL); |
screamer | 0:7a64fbb4069d | 629 | #endif |
screamer | 0:7a64fbb4069d | 630 | /* Call the accept function. */ |
screamer | 0:7a64fbb4069d | 631 | TCP_EVENT_ACCEPT(pcb, ERR_OK, err); |
screamer | 0:7a64fbb4069d | 632 | if (err != ERR_OK) { |
screamer | 0:7a64fbb4069d | 633 | /* If the accept function returns with an error, we abort |
screamer | 0:7a64fbb4069d | 634 | * the connection. */ |
screamer | 0:7a64fbb4069d | 635 | tcp_abort(pcb); |
screamer | 0:7a64fbb4069d | 636 | return ERR_ABRT; |
screamer | 0:7a64fbb4069d | 637 | } |
screamer | 0:7a64fbb4069d | 638 | old_cwnd = pcb->cwnd; |
screamer | 0:7a64fbb4069d | 639 | /* If there was any data contained within this ACK, |
screamer | 0:7a64fbb4069d | 640 | * we'd better pass it on to the application as well. */ |
screamer | 0:7a64fbb4069d | 641 | accepted_inseq = tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 642 | |
screamer | 0:7a64fbb4069d | 643 | pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss); |
screamer | 0:7a64fbb4069d | 644 | |
screamer | 0:7a64fbb4069d | 645 | if ((flags & TCP_FIN) && accepted_inseq) { |
screamer | 0:7a64fbb4069d | 646 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 647 | pcb->state = CLOSE_WAIT; |
screamer | 0:7a64fbb4069d | 648 | } |
screamer | 0:7a64fbb4069d | 649 | } |
screamer | 0:7a64fbb4069d | 650 | /* incorrect ACK number */ |
screamer | 0:7a64fbb4069d | 651 | else { |
screamer | 0:7a64fbb4069d | 652 | /* send RST */ |
screamer | 0:7a64fbb4069d | 653 | struct ip_addr iphdrdest; |
screamer | 0:7a64fbb4069d | 654 | iphdrdest.addr = iphdr->dest.addr; |
screamer | 0:7a64fbb4069d | 655 | struct ip_addr iphdrsrc; |
screamer | 0:7a64fbb4069d | 656 | iphdrsrc.addr = iphdr->src.addr; |
screamer | 0:7a64fbb4069d | 657 | tcp_rst(ackno, seqno + tcplen, &(iphdrdest), &(iphdrsrc), |
screamer | 0:7a64fbb4069d | 658 | tcphdr->dest, tcphdr->src); |
screamer | 0:7a64fbb4069d | 659 | } |
screamer | 0:7a64fbb4069d | 660 | } else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) { |
screamer | 0:7a64fbb4069d | 661 | /* Looks like another copy of the SYN - retransmit our SYN-ACK */ |
screamer | 0:7a64fbb4069d | 662 | tcp_rexmit(pcb); |
screamer | 0:7a64fbb4069d | 663 | } |
screamer | 0:7a64fbb4069d | 664 | break; |
screamer | 0:7a64fbb4069d | 665 | case CLOSE_WAIT: |
screamer | 0:7a64fbb4069d | 666 | /* FALLTHROUGH */ |
screamer | 0:7a64fbb4069d | 667 | case ESTABLISHED: |
screamer | 0:7a64fbb4069d | 668 | accepted_inseq = tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 669 | if ((flags & TCP_FIN) && accepted_inseq) { /* passive close */ |
screamer | 0:7a64fbb4069d | 670 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 671 | pcb->state = CLOSE_WAIT; |
screamer | 0:7a64fbb4069d | 672 | } |
screamer | 0:7a64fbb4069d | 673 | break; |
screamer | 0:7a64fbb4069d | 674 | case FIN_WAIT_1: |
screamer | 0:7a64fbb4069d | 675 | tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 676 | if (flags & TCP_FIN) { |
screamer | 0:7a64fbb4069d | 677 | if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
screamer | 0:7a64fbb4069d | 678 | LWIP_DEBUGF(TCP_DEBUG, |
screamer | 0:7a64fbb4069d | 679 | ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 680 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 681 | tcp_pcb_purge(pcb); |
screamer | 0:7a64fbb4069d | 682 | TCP_RMV(&tcp_active_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 683 | pcb->state = TIME_WAIT; |
screamer | 0:7a64fbb4069d | 684 | TCP_REG(&tcp_tw_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 685 | } else { |
screamer | 0:7a64fbb4069d | 686 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 687 | pcb->state = CLOSING; |
screamer | 0:7a64fbb4069d | 688 | } |
screamer | 0:7a64fbb4069d | 689 | } else if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
screamer | 0:7a64fbb4069d | 690 | pcb->state = FIN_WAIT_2; |
screamer | 0:7a64fbb4069d | 691 | } |
screamer | 0:7a64fbb4069d | 692 | break; |
screamer | 0:7a64fbb4069d | 693 | case FIN_WAIT_2: |
screamer | 0:7a64fbb4069d | 694 | tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 695 | if (flags & TCP_FIN) { |
screamer | 0:7a64fbb4069d | 696 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 697 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 698 | tcp_pcb_purge(pcb); |
screamer | 0:7a64fbb4069d | 699 | TCP_RMV(&tcp_active_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 700 | pcb->state = TIME_WAIT; |
screamer | 0:7a64fbb4069d | 701 | TCP_REG(&tcp_tw_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 702 | } |
screamer | 0:7a64fbb4069d | 703 | break; |
screamer | 0:7a64fbb4069d | 704 | case CLOSING: |
screamer | 0:7a64fbb4069d | 705 | tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 706 | if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
screamer | 0:7a64fbb4069d | 707 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 708 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 709 | tcp_pcb_purge(pcb); |
screamer | 0:7a64fbb4069d | 710 | TCP_RMV(&tcp_active_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 711 | pcb->state = TIME_WAIT; |
screamer | 0:7a64fbb4069d | 712 | TCP_REG(&tcp_tw_pcbs, pcb); |
screamer | 0:7a64fbb4069d | 713 | } |
screamer | 0:7a64fbb4069d | 714 | break; |
screamer | 0:7a64fbb4069d | 715 | case LAST_ACK: |
screamer | 0:7a64fbb4069d | 716 | tcp_receive(pcb); |
screamer | 0:7a64fbb4069d | 717 | if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
screamer | 0:7a64fbb4069d | 718 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
screamer | 0:7a64fbb4069d | 719 | /* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */ |
screamer | 0:7a64fbb4069d | 720 | recv_flags = TF_CLOSED; |
screamer | 0:7a64fbb4069d | 721 | } |
screamer | 0:7a64fbb4069d | 722 | break; |
screamer | 0:7a64fbb4069d | 723 | default: |
screamer | 0:7a64fbb4069d | 724 | break; |
screamer | 0:7a64fbb4069d | 725 | } |
screamer | 0:7a64fbb4069d | 726 | return ERR_OK; |
screamer | 0:7a64fbb4069d | 727 | } |
screamer | 0:7a64fbb4069d | 728 | |
screamer | 0:7a64fbb4069d | 729 | /** |
screamer | 0:7a64fbb4069d | 730 | * Called by tcp_process. Checks if the given segment is an ACK for outstanding |
screamer | 0:7a64fbb4069d | 731 | * data, and if so frees the memory of the buffered data. Next, is places the |
screamer | 0:7a64fbb4069d | 732 | * segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment |
screamer | 0:7a64fbb4069d | 733 | * is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until |
screamer | 0:7a64fbb4069d | 734 | * i it has been removed from the buffer. |
screamer | 0:7a64fbb4069d | 735 | * |
screamer | 0:7a64fbb4069d | 736 | * If the incoming segment constitutes an ACK for a segment that was used for RTT |
screamer | 0:7a64fbb4069d | 737 | * estimation, the RTT is estimated here as well. |
screamer | 0:7a64fbb4069d | 738 | * |
screamer | 0:7a64fbb4069d | 739 | * Called from tcp_process(). |
screamer | 0:7a64fbb4069d | 740 | * |
screamer | 0:7a64fbb4069d | 741 | * @return 1 if the incoming segment is the next in sequence, 0 if not |
screamer | 0:7a64fbb4069d | 742 | */ |
screamer | 0:7a64fbb4069d | 743 | static u8_t |
screamer | 0:7a64fbb4069d | 744 | tcp_receive(struct tcp_pcb *pcb) |
screamer | 0:7a64fbb4069d | 745 | { |
screamer | 0:7a64fbb4069d | 746 | struct tcp_seg *next; |
screamer | 0:7a64fbb4069d | 747 | #if TCP_QUEUE_OOSEQ |
screamer | 0:7a64fbb4069d | 748 | struct tcp_seg *prev, *cseg; |
screamer | 0:7a64fbb4069d | 749 | #endif |
screamer | 0:7a64fbb4069d | 750 | struct pbuf *p; |
screamer | 0:7a64fbb4069d | 751 | s32_t off; |
screamer | 0:7a64fbb4069d | 752 | s16_t m; |
screamer | 0:7a64fbb4069d | 753 | u32_t right_wnd_edge; |
screamer | 0:7a64fbb4069d | 754 | u16_t new_tot_len; |
screamer | 0:7a64fbb4069d | 755 | u8_t accepted_inseq = 0; |
screamer | 0:7a64fbb4069d | 756 | |
screamer | 0:7a64fbb4069d | 757 | if (flags & TCP_ACK) { |
screamer | 0:7a64fbb4069d | 758 | right_wnd_edge = pcb->snd_wnd + pcb->snd_wl1; |
screamer | 0:7a64fbb4069d | 759 | |
screamer | 0:7a64fbb4069d | 760 | /* Update window. */ |
screamer | 0:7a64fbb4069d | 761 | if (TCP_SEQ_LT(pcb->snd_wl1, seqno) || |
screamer | 0:7a64fbb4069d | 762 | (pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) || |
screamer | 0:7a64fbb4069d | 763 | (pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) { |
screamer | 0:7a64fbb4069d | 764 | pcb->snd_wnd = tcphdr->wnd; |
screamer | 0:7a64fbb4069d | 765 | pcb->snd_wl1 = seqno; |
screamer | 0:7a64fbb4069d | 766 | pcb->snd_wl2 = ackno; |
screamer | 0:7a64fbb4069d | 767 | if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) { |
screamer | 0:7a64fbb4069d | 768 | pcb->persist_backoff = 0; |
screamer | 0:7a64fbb4069d | 769 | } |
screamer | 0:7a64fbb4069d | 770 | LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd)); |
screamer | 0:7a64fbb4069d | 771 | #if TCP_WND_DEBUG |
screamer | 0:7a64fbb4069d | 772 | } else { |
screamer | 0:7a64fbb4069d | 773 | if (pcb->snd_wnd != tcphdr->wnd) { |
screamer | 0:7a64fbb4069d | 774 | LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: no window update lastack %"U32_F" snd_max %"U32_F" ackno %"U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 775 | pcb->lastack, pcb->snd_max, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2)); |
screamer | 0:7a64fbb4069d | 776 | } |
screamer | 0:7a64fbb4069d | 777 | #endif /* TCP_WND_DEBUG */ |
screamer | 0:7a64fbb4069d | 778 | } |
screamer | 0:7a64fbb4069d | 779 | |
screamer | 0:7a64fbb4069d | 780 | if (pcb->lastack == ackno) { |
screamer | 0:7a64fbb4069d | 781 | pcb->acked = 0; |
screamer | 0:7a64fbb4069d | 782 | |
screamer | 0:7a64fbb4069d | 783 | if (pcb->snd_wl1 + pcb->snd_wnd == right_wnd_edge){ |
screamer | 0:7a64fbb4069d | 784 | ++pcb->dupacks; |
screamer | 0:7a64fbb4069d | 785 | if (pcb->dupacks >= 3 && pcb->unacked != NULL) { |
screamer | 0:7a64fbb4069d | 786 | if (!(pcb->flags & TF_INFR)) { |
screamer | 0:7a64fbb4069d | 787 | /* This is fast retransmit. Retransmit the first unacked segment. */ |
screamer | 0:7a64fbb4069d | 788 | LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupacks %"U16_F" (%"U32_F"), fast retransmit %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 789 | (u16_t)pcb->dupacks, pcb->lastack, |
screamer | 0:7a64fbb4069d | 790 | ntohl(pcb->unacked->tcphdr->seqno))); |
screamer | 0:7a64fbb4069d | 791 | tcp_rexmit(pcb); |
screamer | 0:7a64fbb4069d | 792 | /* Set ssthresh to max (FlightSize / 2, 2*SMSS) */ |
screamer | 0:7a64fbb4069d | 793 | /*pcb->ssthresh = LWIP_MAX((pcb->snd_max - |
screamer | 0:7a64fbb4069d | 794 | pcb->lastack) / 2, |
screamer | 0:7a64fbb4069d | 795 | 2 * pcb->mss);*/ |
screamer | 0:7a64fbb4069d | 796 | /* Set ssthresh to half of the minimum of the current cwnd and the advertised window */ |
screamer | 0:7a64fbb4069d | 797 | if (pcb->cwnd > pcb->snd_wnd) |
screamer | 0:7a64fbb4069d | 798 | pcb->ssthresh = pcb->snd_wnd / 2; |
screamer | 0:7a64fbb4069d | 799 | else |
screamer | 0:7a64fbb4069d | 800 | pcb->ssthresh = pcb->cwnd / 2; |
screamer | 0:7a64fbb4069d | 801 | |
screamer | 0:7a64fbb4069d | 802 | /* The minimum value for ssthresh should be 2 MSS */ |
screamer | 0:7a64fbb4069d | 803 | if (pcb->ssthresh < 2*pcb->mss) { |
screamer | 0:7a64fbb4069d | 804 | LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: The minimum value for ssthresh %"U16_F" should be min 2 mss %"U16_F"...\n", pcb->ssthresh, 2*pcb->mss)); |
screamer | 0:7a64fbb4069d | 805 | pcb->ssthresh = 2*pcb->mss; |
screamer | 0:7a64fbb4069d | 806 | } |
screamer | 0:7a64fbb4069d | 807 | |
screamer | 0:7a64fbb4069d | 808 | pcb->cwnd = pcb->ssthresh + 3 * pcb->mss; |
screamer | 0:7a64fbb4069d | 809 | pcb->flags |= TF_INFR; |
screamer | 0:7a64fbb4069d | 810 | } else { |
screamer | 0:7a64fbb4069d | 811 | /* Inflate the congestion window, but not if it means that |
screamer | 0:7a64fbb4069d | 812 | the value overflows. */ |
screamer | 0:7a64fbb4069d | 813 | if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { |
screamer | 0:7a64fbb4069d | 814 | pcb->cwnd += pcb->mss; |
screamer | 0:7a64fbb4069d | 815 | } |
screamer | 0:7a64fbb4069d | 816 | } |
screamer | 0:7a64fbb4069d | 817 | } |
screamer | 0:7a64fbb4069d | 818 | } else { |
screamer | 0:7a64fbb4069d | 819 | LWIP_DEBUGF(TCP_FR_DEBUG, ("tcp_receive: dupack averted %"U32_F" %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 820 | pcb->snd_wl1 + pcb->snd_wnd, right_wnd_edge)); |
screamer | 0:7a64fbb4069d | 821 | } |
screamer | 0:7a64fbb4069d | 822 | } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_max)){ |
screamer | 0:7a64fbb4069d | 823 | /* We come here when the ACK acknowledges new data. */ |
screamer | 0:7a64fbb4069d | 824 | |
screamer | 0:7a64fbb4069d | 825 | /* Reset the "IN Fast Retransmit" flag, since we are no longer |
screamer | 0:7a64fbb4069d | 826 | in fast retransmit. Also reset the congestion window to the |
screamer | 0:7a64fbb4069d | 827 | slow start threshold. */ |
screamer | 0:7a64fbb4069d | 828 | if (pcb->flags & TF_INFR) { |
screamer | 0:7a64fbb4069d | 829 | pcb->flags &= ~TF_INFR; |
screamer | 0:7a64fbb4069d | 830 | pcb->cwnd = pcb->ssthresh; |
screamer | 0:7a64fbb4069d | 831 | } |
screamer | 0:7a64fbb4069d | 832 | |
screamer | 0:7a64fbb4069d | 833 | /* Reset the number of retransmissions. */ |
screamer | 0:7a64fbb4069d | 834 | pcb->nrtx = 0; |
screamer | 0:7a64fbb4069d | 835 | |
screamer | 0:7a64fbb4069d | 836 | /* Reset the retransmission time-out. */ |
screamer | 0:7a64fbb4069d | 837 | pcb->rto = (pcb->sa >> 3) + pcb->sv; |
screamer | 0:7a64fbb4069d | 838 | |
screamer | 0:7a64fbb4069d | 839 | /* Update the send buffer space. Diff between the two can never exceed 64K? */ |
screamer | 0:7a64fbb4069d | 840 | pcb->acked = (u16_t)(ackno - pcb->lastack); |
screamer | 0:7a64fbb4069d | 841 | |
screamer | 0:7a64fbb4069d | 842 | pcb->snd_buf += pcb->acked; |
screamer | 0:7a64fbb4069d | 843 | |
screamer | 0:7a64fbb4069d | 844 | /* Reset the fast retransmit variables. */ |
screamer | 0:7a64fbb4069d | 845 | pcb->dupacks = 0; |
screamer | 0:7a64fbb4069d | 846 | pcb->lastack = ackno; |
screamer | 0:7a64fbb4069d | 847 | |
screamer | 0:7a64fbb4069d | 848 | /* Update the congestion control variables (cwnd and |
screamer | 0:7a64fbb4069d | 849 | ssthresh). */ |
screamer | 0:7a64fbb4069d | 850 | if (pcb->state >= ESTABLISHED) { |
screamer | 0:7a64fbb4069d | 851 | if (pcb->cwnd < pcb->ssthresh) { |
screamer | 0:7a64fbb4069d | 852 | if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { |
screamer | 0:7a64fbb4069d | 853 | pcb->cwnd += pcb->mss; |
screamer | 0:7a64fbb4069d | 854 | } |
screamer | 0:7a64fbb4069d | 855 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd)); |
screamer | 0:7a64fbb4069d | 856 | } else { |
screamer | 0:7a64fbb4069d | 857 | u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd); |
screamer | 0:7a64fbb4069d | 858 | if (new_cwnd > pcb->cwnd) { |
screamer | 0:7a64fbb4069d | 859 | pcb->cwnd = new_cwnd; |
screamer | 0:7a64fbb4069d | 860 | } |
screamer | 0:7a64fbb4069d | 861 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd)); |
screamer | 0:7a64fbb4069d | 862 | } |
screamer | 0:7a64fbb4069d | 863 | } |
screamer | 0:7a64fbb4069d | 864 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n", |
screamer | 0:7a64fbb4069d | 865 | ackno, |
screamer | 0:7a64fbb4069d | 866 | pcb->unacked != NULL? |
screamer | 0:7a64fbb4069d | 867 | ntohl(pcb->unacked->tcphdr->seqno): 0, |
screamer | 0:7a64fbb4069d | 868 | pcb->unacked != NULL? |
screamer | 0:7a64fbb4069d | 869 | ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0)); |
screamer | 0:7a64fbb4069d | 870 | |
screamer | 0:7a64fbb4069d | 871 | /* Remove segment from the unacknowledged list if the incoming |
screamer | 0:7a64fbb4069d | 872 | ACK acknowlegdes them. */ |
screamer | 0:7a64fbb4069d | 873 | while (pcb->unacked != NULL && |
screamer | 0:7a64fbb4069d | 874 | TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) + |
screamer | 0:7a64fbb4069d | 875 | TCP_TCPLEN(pcb->unacked), ackno)) { |
screamer | 0:7a64fbb4069d | 876 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n", |
screamer | 0:7a64fbb4069d | 877 | ntohl(pcb->unacked->tcphdr->seqno), |
screamer | 0:7a64fbb4069d | 878 | ntohl(pcb->unacked->tcphdr->seqno) + |
screamer | 0:7a64fbb4069d | 879 | TCP_TCPLEN(pcb->unacked))); |
screamer | 0:7a64fbb4069d | 880 | |
screamer | 0:7a64fbb4069d | 881 | next = pcb->unacked; |
screamer | 0:7a64fbb4069d | 882 | pcb->unacked = pcb->unacked->next; |
screamer | 0:7a64fbb4069d | 883 | |
screamer | 0:7a64fbb4069d | 884 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen)); |
screamer | 0:7a64fbb4069d | 885 | LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p))); |
screamer | 0:7a64fbb4069d | 886 | pcb->snd_queuelen -= pbuf_clen(next->p); |
screamer | 0:7a64fbb4069d | 887 | tcp_seg_free(next); |
screamer | 0:7a64fbb4069d | 888 | |
screamer | 0:7a64fbb4069d | 889 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen)); |
screamer | 0:7a64fbb4069d | 890 | if (pcb->snd_queuelen != 0) { |
screamer | 0:7a64fbb4069d | 891 | LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL || |
screamer | 0:7a64fbb4069d | 892 | pcb->unsent != NULL); |
screamer | 0:7a64fbb4069d | 893 | } |
screamer | 0:7a64fbb4069d | 894 | } |
screamer | 0:7a64fbb4069d | 895 | |
screamer | 0:7a64fbb4069d | 896 | /* If there's nothing left to acknowledge, stop the retransmit |
screamer | 0:7a64fbb4069d | 897 | timer, otherwise reset it to start again */ |
screamer | 0:7a64fbb4069d | 898 | if(pcb->unacked == NULL) |
screamer | 0:7a64fbb4069d | 899 | pcb->rtime = -1; |
screamer | 0:7a64fbb4069d | 900 | else |
screamer | 0:7a64fbb4069d | 901 | pcb->rtime = 0; |
screamer | 0:7a64fbb4069d | 902 | |
screamer | 0:7a64fbb4069d | 903 | pcb->polltmr = 0; |
screamer | 0:7a64fbb4069d | 904 | } else { |
screamer | 0:7a64fbb4069d | 905 | /* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */ |
screamer | 0:7a64fbb4069d | 906 | pcb->acked = 0; |
screamer | 0:7a64fbb4069d | 907 | } |
screamer | 0:7a64fbb4069d | 908 | |
screamer | 0:7a64fbb4069d | 909 | /* We go through the ->unsent list to see if any of the segments |
screamer | 0:7a64fbb4069d | 910 | on the list are acknowledged by the ACK. This may seem |
screamer | 0:7a64fbb4069d | 911 | strange since an "unsent" segment shouldn't be acked. The |
screamer | 0:7a64fbb4069d | 912 | rationale is that lwIP puts all outstanding segments on the |
screamer | 0:7a64fbb4069d | 913 | ->unsent list after a retransmission, so these segments may |
screamer | 0:7a64fbb4069d | 914 | in fact have been sent once. */ |
screamer | 0:7a64fbb4069d | 915 | while (pcb->unsent != NULL && |
screamer | 0:7a64fbb4069d | 916 | /*TCP_SEQ_LEQ(ntohl(pcb->unsent->tcphdr->seqno) + TCP_TCPLEN(pcb->unsent), ackno) && |
screamer | 0:7a64fbb4069d | 917 | TCP_SEQ_LEQ(ackno, pcb->snd_max)*/ |
screamer | 0:7a64fbb4069d | 918 | TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) + TCP_TCPLEN(pcb->unsent), pcb->snd_max) |
screamer | 0:7a64fbb4069d | 919 | ) { |
screamer | 0:7a64fbb4069d | 920 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n", |
screamer | 0:7a64fbb4069d | 921 | ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) + |
screamer | 0:7a64fbb4069d | 922 | TCP_TCPLEN(pcb->unsent))); |
screamer | 0:7a64fbb4069d | 923 | |
screamer | 0:7a64fbb4069d | 924 | next = pcb->unsent; |
screamer | 0:7a64fbb4069d | 925 | pcb->unsent = pcb->unsent->next; |
screamer | 0:7a64fbb4069d | 926 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen)); |
screamer | 0:7a64fbb4069d | 927 | LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p))); |
screamer | 0:7a64fbb4069d | 928 | pcb->snd_queuelen -= pbuf_clen(next->p); |
screamer | 0:7a64fbb4069d | 929 | tcp_seg_free(next); |
screamer | 0:7a64fbb4069d | 930 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen)); |
screamer | 0:7a64fbb4069d | 931 | if (pcb->snd_queuelen != 0) { |
screamer | 0:7a64fbb4069d | 932 | LWIP_ASSERT("tcp_receive: valid queue length", |
screamer | 0:7a64fbb4069d | 933 | pcb->unacked != NULL || pcb->unsent != NULL); |
screamer | 0:7a64fbb4069d | 934 | } |
screamer | 0:7a64fbb4069d | 935 | |
screamer | 0:7a64fbb4069d | 936 | if (pcb->unsent != NULL) { |
screamer | 0:7a64fbb4069d | 937 | pcb->snd_nxt = htonl(pcb->unsent->tcphdr->seqno); |
screamer | 0:7a64fbb4069d | 938 | } |
screamer | 0:7a64fbb4069d | 939 | } |
screamer | 0:7a64fbb4069d | 940 | /* End of ACK for new data processing. */ |
screamer | 0:7a64fbb4069d | 941 | |
screamer | 0:7a64fbb4069d | 942 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n", |
screamer | 0:7a64fbb4069d | 943 | pcb->rttest, pcb->rtseq, ackno)); |
screamer | 0:7a64fbb4069d | 944 | |
screamer | 0:7a64fbb4069d | 945 | /* RTT estimation calculations. This is done by checking if the |
screamer | 0:7a64fbb4069d | 946 | incoming segment acknowledges the segment we use to take a |
screamer | 0:7a64fbb4069d | 947 | round-trip time measurement. */ |
screamer | 0:7a64fbb4069d | 948 | if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) { |
screamer | 0:7a64fbb4069d | 949 | /* diff between this shouldn't exceed 32K since this are tcp timer ticks |
screamer | 0:7a64fbb4069d | 950 | and a round-trip shouldn't be that long... */ |
screamer | 0:7a64fbb4069d | 951 | m = (s16_t)(tcp_ticks - pcb->rttest); |
screamer | 0:7a64fbb4069d | 952 | |
screamer | 0:7a64fbb4069d | 953 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n", |
screamer | 0:7a64fbb4069d | 954 | m, m * TCP_SLOW_INTERVAL)); |
screamer | 0:7a64fbb4069d | 955 | |
screamer | 0:7a64fbb4069d | 956 | /* This is taken directly from VJs original code in his paper */ |
screamer | 0:7a64fbb4069d | 957 | m = m - (pcb->sa >> 3); |
screamer | 0:7a64fbb4069d | 958 | pcb->sa += m; |
screamer | 0:7a64fbb4069d | 959 | if (m < 0) { |
screamer | 0:7a64fbb4069d | 960 | m = -m; |
screamer | 0:7a64fbb4069d | 961 | } |
screamer | 0:7a64fbb4069d | 962 | m = m - (pcb->sv >> 2); |
screamer | 0:7a64fbb4069d | 963 | pcb->sv += m; |
screamer | 0:7a64fbb4069d | 964 | pcb->rto = (pcb->sa >> 3) + pcb->sv; |
screamer | 0:7a64fbb4069d | 965 | |
screamer | 0:7a64fbb4069d | 966 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n", |
screamer | 0:7a64fbb4069d | 967 | pcb->rto, pcb->rto * TCP_SLOW_INTERVAL)); |
screamer | 0:7a64fbb4069d | 968 | |
screamer | 0:7a64fbb4069d | 969 | pcb->rttest = 0; |
screamer | 0:7a64fbb4069d | 970 | } |
screamer | 0:7a64fbb4069d | 971 | } |
screamer | 0:7a64fbb4069d | 972 | |
screamer | 0:7a64fbb4069d | 973 | /* If the incoming segment contains data, we must process it |
screamer | 0:7a64fbb4069d | 974 | further. */ |
screamer | 0:7a64fbb4069d | 975 | if (tcplen > 0) { |
screamer | 0:7a64fbb4069d | 976 | /* This code basically does three things: |
screamer | 0:7a64fbb4069d | 977 | |
screamer | 0:7a64fbb4069d | 978 | +) If the incoming segment contains data that is the next |
screamer | 0:7a64fbb4069d | 979 | in-sequence data, this data is passed to the application. This |
screamer | 0:7a64fbb4069d | 980 | might involve trimming the first edge of the data. The rcv_nxt |
screamer | 0:7a64fbb4069d | 981 | variable and the advertised window are adjusted. |
screamer | 0:7a64fbb4069d | 982 | |
screamer | 0:7a64fbb4069d | 983 | +) If the incoming segment has data that is above the next |
screamer | 0:7a64fbb4069d | 984 | sequence number expected (->rcv_nxt), the segment is placed on |
screamer | 0:7a64fbb4069d | 985 | the ->ooseq queue. This is done by finding the appropriate |
screamer | 0:7a64fbb4069d | 986 | place in the ->ooseq queue (which is ordered by sequence |
screamer | 0:7a64fbb4069d | 987 | number) and trim the segment in both ends if needed. An |
screamer | 0:7a64fbb4069d | 988 | immediate ACK is sent to indicate that we received an |
screamer | 0:7a64fbb4069d | 989 | out-of-sequence segment. |
screamer | 0:7a64fbb4069d | 990 | |
screamer | 0:7a64fbb4069d | 991 | +) Finally, we check if the first segment on the ->ooseq queue |
screamer | 0:7a64fbb4069d | 992 | now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If |
screamer | 0:7a64fbb4069d | 993 | rcv_nxt > ooseq->seqno, we must trim the first edge of the |
screamer | 0:7a64fbb4069d | 994 | segment on ->ooseq before we adjust rcv_nxt. The data in the |
screamer | 0:7a64fbb4069d | 995 | segments that are now on sequence are chained onto the |
screamer | 0:7a64fbb4069d | 996 | incoming segment so that we only need to call the application |
screamer | 0:7a64fbb4069d | 997 | once. |
screamer | 0:7a64fbb4069d | 998 | */ |
screamer | 0:7a64fbb4069d | 999 | |
screamer | 0:7a64fbb4069d | 1000 | /* First, we check if we must trim the first edge. We have to do |
screamer | 0:7a64fbb4069d | 1001 | this if the sequence number of the incoming segment is less |
screamer | 0:7a64fbb4069d | 1002 | than rcv_nxt, and the sequence number plus the length of the |
screamer | 0:7a64fbb4069d | 1003 | segment is larger than rcv_nxt. */ |
screamer | 0:7a64fbb4069d | 1004 | /* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){ |
screamer | 0:7a64fbb4069d | 1005 | if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/ |
screamer | 0:7a64fbb4069d | 1006 | if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){ |
screamer | 0:7a64fbb4069d | 1007 | /* Trimming the first edge is done by pushing the payload |
screamer | 0:7a64fbb4069d | 1008 | pointer in the pbuf downwards. This is somewhat tricky since |
screamer | 0:7a64fbb4069d | 1009 | we do not want to discard the full contents of the pbuf up to |
screamer | 0:7a64fbb4069d | 1010 | the new starting point of the data since we have to keep the |
screamer | 0:7a64fbb4069d | 1011 | TCP header which is present in the first pbuf in the chain. |
screamer | 0:7a64fbb4069d | 1012 | |
screamer | 0:7a64fbb4069d | 1013 | What is done is really quite a nasty hack: the first pbuf in |
screamer | 0:7a64fbb4069d | 1014 | the pbuf chain is pointed to by inseg.p. Since we need to be |
screamer | 0:7a64fbb4069d | 1015 | able to deallocate the whole pbuf, we cannot change this |
screamer | 0:7a64fbb4069d | 1016 | inseg.p pointer to point to any of the later pbufs in the |
screamer | 0:7a64fbb4069d | 1017 | chain. Instead, we point the ->payload pointer in the first |
screamer | 0:7a64fbb4069d | 1018 | pbuf to data in one of the later pbufs. We also set the |
screamer | 0:7a64fbb4069d | 1019 | inseg.data pointer to point to the right place. This way, the |
screamer | 0:7a64fbb4069d | 1020 | ->p pointer will still point to the first pbuf, but the |
screamer | 0:7a64fbb4069d | 1021 | ->p->payload pointer will point to data in another pbuf. |
screamer | 0:7a64fbb4069d | 1022 | |
screamer | 0:7a64fbb4069d | 1023 | After we are done with adjusting the pbuf pointers we must |
screamer | 0:7a64fbb4069d | 1024 | adjust the ->data pointer in the seg and the segment |
screamer | 0:7a64fbb4069d | 1025 | length.*/ |
screamer | 0:7a64fbb4069d | 1026 | |
screamer | 0:7a64fbb4069d | 1027 | off = pcb->rcv_nxt - seqno; |
screamer | 0:7a64fbb4069d | 1028 | p = inseg.p; |
screamer | 0:7a64fbb4069d | 1029 | LWIP_ASSERT("inseg.p != NULL", inseg.p); |
screamer | 0:7a64fbb4069d | 1030 | LWIP_ASSERT("insane offset!", (off < 0x7fff)); |
screamer | 0:7a64fbb4069d | 1031 | if (inseg.p->len < off) { |
screamer | 0:7a64fbb4069d | 1032 | LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off)); |
screamer | 0:7a64fbb4069d | 1033 | new_tot_len = (u16_t)(inseg.p->tot_len - off); |
screamer | 0:7a64fbb4069d | 1034 | while (p->len < off) { |
screamer | 0:7a64fbb4069d | 1035 | off -= p->len; |
screamer | 0:7a64fbb4069d | 1036 | /* KJM following line changed (with addition of new_tot_len var) |
screamer | 0:7a64fbb4069d | 1037 | to fix bug #9076 |
screamer | 0:7a64fbb4069d | 1038 | inseg.p->tot_len -= p->len; */ |
screamer | 0:7a64fbb4069d | 1039 | p->tot_len = new_tot_len; |
screamer | 0:7a64fbb4069d | 1040 | p->len = 0; |
screamer | 0:7a64fbb4069d | 1041 | p = p->next; |
screamer | 0:7a64fbb4069d | 1042 | } |
screamer | 0:7a64fbb4069d | 1043 | if(pbuf_header(p, (s16_t)-off)) { |
screamer | 0:7a64fbb4069d | 1044 | /* Do we need to cope with this failing? Assert for now */ |
screamer | 0:7a64fbb4069d | 1045 | LWIP_ASSERT("pbuf_header failed", 0); |
screamer | 0:7a64fbb4069d | 1046 | } |
screamer | 0:7a64fbb4069d | 1047 | } else { |
screamer | 0:7a64fbb4069d | 1048 | if(pbuf_header(inseg.p, (s16_t)-off)) { |
screamer | 0:7a64fbb4069d | 1049 | /* Do we need to cope with this failing? Assert for now */ |
screamer | 0:7a64fbb4069d | 1050 | LWIP_ASSERT("pbuf_header failed", 0); |
screamer | 0:7a64fbb4069d | 1051 | } |
screamer | 0:7a64fbb4069d | 1052 | } |
screamer | 0:7a64fbb4069d | 1053 | /* KJM following line changed to use p->payload rather than inseg->p->payload |
screamer | 0:7a64fbb4069d | 1054 | to fix bug #9076 */ |
screamer | 0:7a64fbb4069d | 1055 | inseg.dataptr = p->payload; |
screamer | 0:7a64fbb4069d | 1056 | inseg.len -= (u16_t)(pcb->rcv_nxt - seqno); |
screamer | 0:7a64fbb4069d | 1057 | inseg.tcphdr->seqno = seqno = pcb->rcv_nxt; |
screamer | 0:7a64fbb4069d | 1058 | } |
screamer | 0:7a64fbb4069d | 1059 | else { |
screamer | 0:7a64fbb4069d | 1060 | if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){ |
screamer | 0:7a64fbb4069d | 1061 | /* the whole segment is < rcv_nxt */ |
screamer | 0:7a64fbb4069d | 1062 | /* must be a duplicate of a packet that has already been correctly handled */ |
screamer | 0:7a64fbb4069d | 1063 | |
screamer | 0:7a64fbb4069d | 1064 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno)); |
screamer | 0:7a64fbb4069d | 1065 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 1066 | } |
screamer | 0:7a64fbb4069d | 1067 | } |
screamer | 0:7a64fbb4069d | 1068 | |
screamer | 0:7a64fbb4069d | 1069 | /* The sequence number must be within the window (above rcv_nxt |
screamer | 0:7a64fbb4069d | 1070 | and below rcv_nxt + rcv_wnd) in order to be further |
screamer | 0:7a64fbb4069d | 1071 | processed. */ |
screamer | 0:7a64fbb4069d | 1072 | if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, |
screamer | 0:7a64fbb4069d | 1073 | pcb->rcv_nxt + pcb->rcv_wnd - 1)){ |
screamer | 0:7a64fbb4069d | 1074 | if (pcb->rcv_nxt == seqno) { |
screamer | 0:7a64fbb4069d | 1075 | accepted_inseq = 1; |
screamer | 0:7a64fbb4069d | 1076 | /* The incoming segment is the next in sequence. We check if |
screamer | 0:7a64fbb4069d | 1077 | we have to trim the end of the segment and update rcv_nxt |
screamer | 0:7a64fbb4069d | 1078 | and pass the data to the application. */ |
screamer | 0:7a64fbb4069d | 1079 | #if TCP_QUEUE_OOSEQ |
screamer | 0:7a64fbb4069d | 1080 | if (pcb->ooseq != NULL && |
screamer | 0:7a64fbb4069d | 1081 | TCP_SEQ_LEQ(pcb->ooseq->tcphdr->seqno, seqno + inseg.len)) { |
screamer | 0:7a64fbb4069d | 1082 | if (pcb->ooseq->len > 0) { |
screamer | 0:7a64fbb4069d | 1083 | /* We have to trim the second edge of the incoming |
screamer | 0:7a64fbb4069d | 1084 | segment. */ |
screamer | 0:7a64fbb4069d | 1085 | inseg.len = (u16_t)(pcb->ooseq->tcphdr->seqno - seqno); |
screamer | 0:7a64fbb4069d | 1086 | pbuf_realloc(inseg.p, inseg.len); |
screamer | 0:7a64fbb4069d | 1087 | } else { |
screamer | 0:7a64fbb4069d | 1088 | /* does the ooseq segment contain only flags that are in inseg also? */ |
screamer | 0:7a64fbb4069d | 1089 | if ((TCPH_FLAGS(inseg.tcphdr) & (TCP_FIN|TCP_SYN)) == |
screamer | 0:7a64fbb4069d | 1090 | (TCPH_FLAGS(pcb->ooseq->tcphdr) & (TCP_FIN|TCP_SYN))) { |
screamer | 0:7a64fbb4069d | 1091 | struct tcp_seg *old_ooseq = pcb->ooseq; |
screamer | 0:7a64fbb4069d | 1092 | pcb->ooseq = pcb->ooseq->next; |
screamer | 0:7a64fbb4069d | 1093 | memp_free(MEMP_TCP_SEG, old_ooseq); |
screamer | 0:7a64fbb4069d | 1094 | } |
screamer | 0:7a64fbb4069d | 1095 | } |
screamer | 0:7a64fbb4069d | 1096 | } |
screamer | 0:7a64fbb4069d | 1097 | #endif /* TCP_QUEUE_OOSEQ */ |
screamer | 0:7a64fbb4069d | 1098 | |
screamer | 0:7a64fbb4069d | 1099 | tcplen = TCP_TCPLEN(&inseg); |
screamer | 0:7a64fbb4069d | 1100 | |
screamer | 0:7a64fbb4069d | 1101 | /* First received FIN will be ACKed +1, on any successive (duplicate) |
screamer | 0:7a64fbb4069d | 1102 | * FINs we are already in CLOSE_WAIT and have already done +1. |
screamer | 0:7a64fbb4069d | 1103 | */ |
screamer | 0:7a64fbb4069d | 1104 | if (pcb->state != CLOSE_WAIT) { |
screamer | 0:7a64fbb4069d | 1105 | pcb->rcv_nxt += tcplen; |
screamer | 0:7a64fbb4069d | 1106 | } |
screamer | 0:7a64fbb4069d | 1107 | |
screamer | 0:7a64fbb4069d | 1108 | /* Update the receiver's (our) window. */ |
screamer | 0:7a64fbb4069d | 1109 | if (pcb->rcv_wnd < tcplen) { |
screamer | 0:7a64fbb4069d | 1110 | pcb->rcv_wnd = 0; |
screamer | 0:7a64fbb4069d | 1111 | } else { |
screamer | 0:7a64fbb4069d | 1112 | pcb->rcv_wnd -= tcplen; |
screamer | 0:7a64fbb4069d | 1113 | } |
screamer | 0:7a64fbb4069d | 1114 | |
screamer | 0:7a64fbb4069d | 1115 | tcp_update_rcv_ann_wnd(pcb); |
screamer | 0:7a64fbb4069d | 1116 | |
screamer | 0:7a64fbb4069d | 1117 | /* If there is data in the segment, we make preparations to |
screamer | 0:7a64fbb4069d | 1118 | pass this up to the application. The ->recv_data variable |
screamer | 0:7a64fbb4069d | 1119 | is used for holding the pbuf that goes to the |
screamer | 0:7a64fbb4069d | 1120 | application. The code for reassembling out-of-sequence data |
screamer | 0:7a64fbb4069d | 1121 | chains its data on this pbuf as well. |
screamer | 0:7a64fbb4069d | 1122 | |
screamer | 0:7a64fbb4069d | 1123 | If the segment was a FIN, we set the TF_GOT_FIN flag that will |
screamer | 0:7a64fbb4069d | 1124 | be used to indicate to the application that the remote side has |
screamer | 0:7a64fbb4069d | 1125 | closed its end of the connection. */ |
screamer | 0:7a64fbb4069d | 1126 | if (inseg.p->tot_len > 0) { |
screamer | 0:7a64fbb4069d | 1127 | recv_data = inseg.p; |
screamer | 0:7a64fbb4069d | 1128 | /* Since this pbuf now is the responsibility of the |
screamer | 0:7a64fbb4069d | 1129 | application, we delete our reference to it so that we won't |
screamer | 0:7a64fbb4069d | 1130 | (mistakingly) deallocate it. */ |
screamer | 0:7a64fbb4069d | 1131 | inseg.p = NULL; |
screamer | 0:7a64fbb4069d | 1132 | } |
screamer | 0:7a64fbb4069d | 1133 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) { |
screamer | 0:7a64fbb4069d | 1134 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n")); |
screamer | 0:7a64fbb4069d | 1135 | recv_flags = TF_GOT_FIN; |
screamer | 0:7a64fbb4069d | 1136 | } |
screamer | 0:7a64fbb4069d | 1137 | |
screamer | 0:7a64fbb4069d | 1138 | #if TCP_QUEUE_OOSEQ |
screamer | 0:7a64fbb4069d | 1139 | /* We now check if we have segments on the ->ooseq queue that |
screamer | 0:7a64fbb4069d | 1140 | is now in sequence. */ |
screamer | 0:7a64fbb4069d | 1141 | while (pcb->ooseq != NULL && |
screamer | 0:7a64fbb4069d | 1142 | pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) { |
screamer | 0:7a64fbb4069d | 1143 | |
screamer | 0:7a64fbb4069d | 1144 | cseg = pcb->ooseq; |
screamer | 0:7a64fbb4069d | 1145 | seqno = pcb->ooseq->tcphdr->seqno; |
screamer | 0:7a64fbb4069d | 1146 | |
screamer | 0:7a64fbb4069d | 1147 | pcb->rcv_nxt += TCP_TCPLEN(cseg); |
screamer | 0:7a64fbb4069d | 1148 | if (pcb->rcv_wnd < TCP_TCPLEN(cseg)) { |
screamer | 0:7a64fbb4069d | 1149 | pcb->rcv_wnd = 0; |
screamer | 0:7a64fbb4069d | 1150 | } else { |
screamer | 0:7a64fbb4069d | 1151 | pcb->rcv_wnd -= TCP_TCPLEN(cseg); |
screamer | 0:7a64fbb4069d | 1152 | } |
screamer | 0:7a64fbb4069d | 1153 | |
screamer | 0:7a64fbb4069d | 1154 | tcp_update_rcv_ann_wnd(pcb); |
screamer | 0:7a64fbb4069d | 1155 | |
screamer | 0:7a64fbb4069d | 1156 | if (cseg->p->tot_len > 0) { |
screamer | 0:7a64fbb4069d | 1157 | /* Chain this pbuf onto the pbuf that we will pass to |
screamer | 0:7a64fbb4069d | 1158 | the application. */ |
screamer | 0:7a64fbb4069d | 1159 | if (recv_data) { |
screamer | 0:7a64fbb4069d | 1160 | pbuf_cat(recv_data, cseg->p); |
screamer | 0:7a64fbb4069d | 1161 | } else { |
screamer | 0:7a64fbb4069d | 1162 | recv_data = cseg->p; |
screamer | 0:7a64fbb4069d | 1163 | } |
screamer | 0:7a64fbb4069d | 1164 | cseg->p = NULL; |
screamer | 0:7a64fbb4069d | 1165 | } |
screamer | 0:7a64fbb4069d | 1166 | if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) { |
screamer | 0:7a64fbb4069d | 1167 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n")); |
screamer | 0:7a64fbb4069d | 1168 | recv_flags = TF_GOT_FIN; |
screamer | 0:7a64fbb4069d | 1169 | if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */ |
screamer | 0:7a64fbb4069d | 1170 | pcb->state = CLOSE_WAIT; |
screamer | 0:7a64fbb4069d | 1171 | } |
screamer | 0:7a64fbb4069d | 1172 | } |
screamer | 0:7a64fbb4069d | 1173 | |
screamer | 0:7a64fbb4069d | 1174 | |
screamer | 0:7a64fbb4069d | 1175 | pcb->ooseq = cseg->next; |
screamer | 0:7a64fbb4069d | 1176 | tcp_seg_free(cseg); |
screamer | 0:7a64fbb4069d | 1177 | } |
screamer | 0:7a64fbb4069d | 1178 | #endif /* TCP_QUEUE_OOSEQ */ |
screamer | 0:7a64fbb4069d | 1179 | |
screamer | 0:7a64fbb4069d | 1180 | |
screamer | 0:7a64fbb4069d | 1181 | /* Acknowledge the segment(s). */ |
screamer | 0:7a64fbb4069d | 1182 | tcp_ack(pcb); |
screamer | 0:7a64fbb4069d | 1183 | |
screamer | 0:7a64fbb4069d | 1184 | } else { |
screamer | 0:7a64fbb4069d | 1185 | /* We get here if the incoming segment is out-of-sequence. */ |
screamer | 0:7a64fbb4069d | 1186 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 1187 | #if TCP_QUEUE_OOSEQ |
screamer | 0:7a64fbb4069d | 1188 | /* We queue the segment on the ->ooseq queue. */ |
screamer | 0:7a64fbb4069d | 1189 | if (pcb->ooseq == NULL) { |
screamer | 0:7a64fbb4069d | 1190 | pcb->ooseq = tcp_seg_copy(&inseg); |
screamer | 0:7a64fbb4069d | 1191 | } else { |
screamer | 0:7a64fbb4069d | 1192 | /* If the queue is not empty, we walk through the queue and |
screamer | 0:7a64fbb4069d | 1193 | try to find a place where the sequence number of the |
screamer | 0:7a64fbb4069d | 1194 | incoming segment is between the sequence numbers of the |
screamer | 0:7a64fbb4069d | 1195 | previous and the next segment on the ->ooseq queue. That is |
screamer | 0:7a64fbb4069d | 1196 | the place where we put the incoming segment. If needed, we |
screamer | 0:7a64fbb4069d | 1197 | trim the second edges of the previous and the incoming |
screamer | 0:7a64fbb4069d | 1198 | segment so that it will fit into the sequence. |
screamer | 0:7a64fbb4069d | 1199 | |
screamer | 0:7a64fbb4069d | 1200 | If the incoming segment has the same sequence number as a |
screamer | 0:7a64fbb4069d | 1201 | segment on the ->ooseq queue, we discard the segment that |
screamer | 0:7a64fbb4069d | 1202 | contains less data. */ |
screamer | 0:7a64fbb4069d | 1203 | |
screamer | 0:7a64fbb4069d | 1204 | prev = NULL; |
screamer | 0:7a64fbb4069d | 1205 | for(next = pcb->ooseq; next != NULL; next = next->next) { |
screamer | 0:7a64fbb4069d | 1206 | if (seqno == next->tcphdr->seqno) { |
screamer | 0:7a64fbb4069d | 1207 | /* The sequence number of the incoming segment is the |
screamer | 0:7a64fbb4069d | 1208 | same as the sequence number of the segment on |
screamer | 0:7a64fbb4069d | 1209 | ->ooseq. We check the lengths to see which one to |
screamer | 0:7a64fbb4069d | 1210 | discard. */ |
screamer | 0:7a64fbb4069d | 1211 | if (inseg.len > next->len) { |
screamer | 0:7a64fbb4069d | 1212 | /* The incoming segment is larger than the old |
screamer | 0:7a64fbb4069d | 1213 | segment. We replace the old segment with the new |
screamer | 0:7a64fbb4069d | 1214 | one. */ |
screamer | 0:7a64fbb4069d | 1215 | cseg = tcp_seg_copy(&inseg); |
screamer | 0:7a64fbb4069d | 1216 | if (cseg != NULL) { |
screamer | 0:7a64fbb4069d | 1217 | cseg->next = next->next; |
screamer | 0:7a64fbb4069d | 1218 | if (prev != NULL) { |
screamer | 0:7a64fbb4069d | 1219 | prev->next = cseg; |
screamer | 0:7a64fbb4069d | 1220 | } else { |
screamer | 0:7a64fbb4069d | 1221 | pcb->ooseq = cseg; |
screamer | 0:7a64fbb4069d | 1222 | } |
screamer | 0:7a64fbb4069d | 1223 | tcp_seg_free(next); |
screamer | 0:7a64fbb4069d | 1224 | if (cseg->next != NULL) { |
screamer | 0:7a64fbb4069d | 1225 | next = cseg->next; |
screamer | 0:7a64fbb4069d | 1226 | if (TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) { |
screamer | 0:7a64fbb4069d | 1227 | /* We need to trim the incoming segment. */ |
screamer | 0:7a64fbb4069d | 1228 | cseg->len = (u16_t)(next->tcphdr->seqno - seqno); |
screamer | 0:7a64fbb4069d | 1229 | pbuf_realloc(cseg->p, cseg->len); |
screamer | 0:7a64fbb4069d | 1230 | } |
screamer | 0:7a64fbb4069d | 1231 | } |
screamer | 0:7a64fbb4069d | 1232 | } |
screamer | 0:7a64fbb4069d | 1233 | break; |
screamer | 0:7a64fbb4069d | 1234 | } else { |
screamer | 0:7a64fbb4069d | 1235 | /* Either the lenghts are the same or the incoming |
screamer | 0:7a64fbb4069d | 1236 | segment was smaller than the old one; in either |
screamer | 0:7a64fbb4069d | 1237 | case, we ditch the incoming segment. */ |
screamer | 0:7a64fbb4069d | 1238 | break; |
screamer | 0:7a64fbb4069d | 1239 | } |
screamer | 0:7a64fbb4069d | 1240 | } else { |
screamer | 0:7a64fbb4069d | 1241 | if (prev == NULL) { |
screamer | 0:7a64fbb4069d | 1242 | if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) { |
screamer | 0:7a64fbb4069d | 1243 | /* The sequence number of the incoming segment is lower |
screamer | 0:7a64fbb4069d | 1244 | than the sequence number of the first segment on the |
screamer | 0:7a64fbb4069d | 1245 | queue. We put the incoming segment first on the |
screamer | 0:7a64fbb4069d | 1246 | queue. */ |
screamer | 0:7a64fbb4069d | 1247 | |
screamer | 0:7a64fbb4069d | 1248 | if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) { |
screamer | 0:7a64fbb4069d | 1249 | /* We need to trim the incoming segment. */ |
screamer | 0:7a64fbb4069d | 1250 | inseg.len = (u16_t)(next->tcphdr->seqno - seqno); |
screamer | 0:7a64fbb4069d | 1251 | pbuf_realloc(inseg.p, inseg.len); |
screamer | 0:7a64fbb4069d | 1252 | } |
screamer | 0:7a64fbb4069d | 1253 | cseg = tcp_seg_copy(&inseg); |
screamer | 0:7a64fbb4069d | 1254 | if (cseg != NULL) { |
screamer | 0:7a64fbb4069d | 1255 | cseg->next = next; |
screamer | 0:7a64fbb4069d | 1256 | pcb->ooseq = cseg; |
screamer | 0:7a64fbb4069d | 1257 | } |
screamer | 0:7a64fbb4069d | 1258 | break; |
screamer | 0:7a64fbb4069d | 1259 | } |
screamer | 0:7a64fbb4069d | 1260 | } else |
screamer | 0:7a64fbb4069d | 1261 | /*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) && |
screamer | 0:7a64fbb4069d | 1262 | TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/ |
screamer | 0:7a64fbb4069d | 1263 | if(TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)){ |
screamer | 0:7a64fbb4069d | 1264 | /* The sequence number of the incoming segment is in |
screamer | 0:7a64fbb4069d | 1265 | between the sequence numbers of the previous and |
screamer | 0:7a64fbb4069d | 1266 | the next segment on ->ooseq. We trim and insert the |
screamer | 0:7a64fbb4069d | 1267 | incoming segment and trim the previous segment, if |
screamer | 0:7a64fbb4069d | 1268 | needed. */ |
screamer | 0:7a64fbb4069d | 1269 | if (TCP_SEQ_GT(seqno + inseg.len, next->tcphdr->seqno)) { |
screamer | 0:7a64fbb4069d | 1270 | /* We need to trim the incoming segment. */ |
screamer | 0:7a64fbb4069d | 1271 | inseg.len = (u16_t)(next->tcphdr->seqno - seqno); |
screamer | 0:7a64fbb4069d | 1272 | pbuf_realloc(inseg.p, inseg.len); |
screamer | 0:7a64fbb4069d | 1273 | } |
screamer | 0:7a64fbb4069d | 1274 | |
screamer | 0:7a64fbb4069d | 1275 | cseg = tcp_seg_copy(&inseg); |
screamer | 0:7a64fbb4069d | 1276 | if (cseg != NULL) { |
screamer | 0:7a64fbb4069d | 1277 | cseg->next = next; |
screamer | 0:7a64fbb4069d | 1278 | prev->next = cseg; |
screamer | 0:7a64fbb4069d | 1279 | if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) { |
screamer | 0:7a64fbb4069d | 1280 | /* We need to trim the prev segment. */ |
screamer | 0:7a64fbb4069d | 1281 | prev->len = (u16_t)(seqno - prev->tcphdr->seqno); |
screamer | 0:7a64fbb4069d | 1282 | pbuf_realloc(prev->p, prev->len); |
screamer | 0:7a64fbb4069d | 1283 | } |
screamer | 0:7a64fbb4069d | 1284 | } |
screamer | 0:7a64fbb4069d | 1285 | break; |
screamer | 0:7a64fbb4069d | 1286 | } |
screamer | 0:7a64fbb4069d | 1287 | /* If the "next" segment is the last segment on the |
screamer | 0:7a64fbb4069d | 1288 | ooseq queue, we add the incoming segment to the end |
screamer | 0:7a64fbb4069d | 1289 | of the list. */ |
screamer | 0:7a64fbb4069d | 1290 | if (next->next == NULL && |
screamer | 0:7a64fbb4069d | 1291 | TCP_SEQ_GT(seqno, next->tcphdr->seqno)) { |
screamer | 0:7a64fbb4069d | 1292 | next->next = tcp_seg_copy(&inseg); |
screamer | 0:7a64fbb4069d | 1293 | if (next->next != NULL) { |
screamer | 0:7a64fbb4069d | 1294 | if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) { |
screamer | 0:7a64fbb4069d | 1295 | /* We need to trim the last segment. */ |
screamer | 0:7a64fbb4069d | 1296 | next->len = (u16_t)(seqno - next->tcphdr->seqno); |
screamer | 0:7a64fbb4069d | 1297 | pbuf_realloc(next->p, next->len); |
screamer | 0:7a64fbb4069d | 1298 | } |
screamer | 0:7a64fbb4069d | 1299 | } |
screamer | 0:7a64fbb4069d | 1300 | break; |
screamer | 0:7a64fbb4069d | 1301 | } |
screamer | 0:7a64fbb4069d | 1302 | } |
screamer | 0:7a64fbb4069d | 1303 | prev = next; |
screamer | 0:7a64fbb4069d | 1304 | } |
screamer | 0:7a64fbb4069d | 1305 | } |
screamer | 0:7a64fbb4069d | 1306 | #endif /* TCP_QUEUE_OOSEQ */ |
screamer | 0:7a64fbb4069d | 1307 | |
screamer | 0:7a64fbb4069d | 1308 | } |
screamer | 0:7a64fbb4069d | 1309 | } else { |
screamer | 0:7a64fbb4069d | 1310 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 1311 | } |
screamer | 0:7a64fbb4069d | 1312 | } else { |
screamer | 0:7a64fbb4069d | 1313 | /* Segments with length 0 is taken care of here. Segments that |
screamer | 0:7a64fbb4069d | 1314 | fall out of the window are ACKed. */ |
screamer | 0:7a64fbb4069d | 1315 | /*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) || |
screamer | 0:7a64fbb4069d | 1316 | TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/ |
screamer | 0:7a64fbb4069d | 1317 | if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){ |
screamer | 0:7a64fbb4069d | 1318 | tcp_ack_now(pcb); |
screamer | 0:7a64fbb4069d | 1319 | } |
screamer | 0:7a64fbb4069d | 1320 | } |
screamer | 0:7a64fbb4069d | 1321 | return accepted_inseq; |
screamer | 0:7a64fbb4069d | 1322 | } |
screamer | 0:7a64fbb4069d | 1323 | |
screamer | 0:7a64fbb4069d | 1324 | /** |
screamer | 0:7a64fbb4069d | 1325 | * Parses the options contained in the incoming segment. |
screamer | 0:7a64fbb4069d | 1326 | * |
screamer | 0:7a64fbb4069d | 1327 | * Called from tcp_listen_input() and tcp_process(). |
screamer | 0:7a64fbb4069d | 1328 | * Currently, only the MSS option is supported! |
screamer | 0:7a64fbb4069d | 1329 | * |
screamer | 0:7a64fbb4069d | 1330 | * @param pcb the tcp_pcb for which a segment arrived |
screamer | 0:7a64fbb4069d | 1331 | */ |
screamer | 0:7a64fbb4069d | 1332 | static void |
screamer | 0:7a64fbb4069d | 1333 | tcp_parseopt(struct tcp_pcb *pcb) |
screamer | 0:7a64fbb4069d | 1334 | { |
screamer | 0:7a64fbb4069d | 1335 | u16_t c, max_c; |
screamer | 0:7a64fbb4069d | 1336 | u16_t mss; |
screamer | 0:7a64fbb4069d | 1337 | u8_t *opts, opt; |
screamer | 0:7a64fbb4069d | 1338 | #if LWIP_TCP_TIMESTAMPS |
screamer | 0:7a64fbb4069d | 1339 | u32_t tsval; |
screamer | 0:7a64fbb4069d | 1340 | #endif |
screamer | 0:7a64fbb4069d | 1341 | |
screamer | 0:7a64fbb4069d | 1342 | opts = (u8_t *)tcphdr + TCP_HLEN; |
screamer | 0:7a64fbb4069d | 1343 | |
screamer | 0:7a64fbb4069d | 1344 | /* Parse the TCP MSS option, if present. */ |
screamer | 0:7a64fbb4069d | 1345 | if(TCPH_HDRLEN(tcphdr) > 0x5) { |
screamer | 0:7a64fbb4069d | 1346 | max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2; |
screamer | 0:7a64fbb4069d | 1347 | for (c = 0; c < max_c; ) { |
screamer | 0:7a64fbb4069d | 1348 | opt = opts[c]; |
screamer | 0:7a64fbb4069d | 1349 | switch (opt) { |
screamer | 0:7a64fbb4069d | 1350 | case 0x00: |
screamer | 0:7a64fbb4069d | 1351 | /* End of options. */ |
screamer | 0:7a64fbb4069d | 1352 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n")); |
screamer | 0:7a64fbb4069d | 1353 | return; |
screamer | 0:7a64fbb4069d | 1354 | case 0x01: |
screamer | 0:7a64fbb4069d | 1355 | /* NOP option. */ |
screamer | 0:7a64fbb4069d | 1356 | ++c; |
screamer | 0:7a64fbb4069d | 1357 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n")); |
screamer | 0:7a64fbb4069d | 1358 | break; |
screamer | 0:7a64fbb4069d | 1359 | case 0x02: |
screamer | 0:7a64fbb4069d | 1360 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n")); |
screamer | 0:7a64fbb4069d | 1361 | if (opts[c + 1] != 0x04 || c + 0x04 > max_c) { |
screamer | 0:7a64fbb4069d | 1362 | /* Bad length */ |
screamer | 0:7a64fbb4069d | 1363 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
screamer | 0:7a64fbb4069d | 1364 | return; |
screamer | 0:7a64fbb4069d | 1365 | } |
screamer | 0:7a64fbb4069d | 1366 | /* An MSS option with the right option length. */ |
screamer | 0:7a64fbb4069d | 1367 | mss = (opts[c + 2] << 8) | opts[c + 3]; |
screamer | 0:7a64fbb4069d | 1368 | /* Limit the mss to the configured TCP_MSS and prevent division by zero */ |
screamer | 0:7a64fbb4069d | 1369 | pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss; |
screamer | 0:7a64fbb4069d | 1370 | /* Advance to next option */ |
screamer | 0:7a64fbb4069d | 1371 | c += 0x04; |
screamer | 0:7a64fbb4069d | 1372 | break; |
screamer | 0:7a64fbb4069d | 1373 | #if LWIP_TCP_TIMESTAMPS |
screamer | 0:7a64fbb4069d | 1374 | case 0x08: |
screamer | 0:7a64fbb4069d | 1375 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n")); |
screamer | 0:7a64fbb4069d | 1376 | if (opts[c + 1] != 0x0A || c + 0x0A > max_c) { |
screamer | 0:7a64fbb4069d | 1377 | /* Bad length */ |
screamer | 0:7a64fbb4069d | 1378 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
screamer | 0:7a64fbb4069d | 1379 | return; |
screamer | 0:7a64fbb4069d | 1380 | } |
screamer | 0:7a64fbb4069d | 1381 | /* TCP timestamp option with valid length */ |
screamer | 0:7a64fbb4069d | 1382 | tsval = (opts[c+2]) | (opts[c+3] << 8) | |
screamer | 0:7a64fbb4069d | 1383 | (opts[c+4] << 16) | (opts[c+5] << 24); |
screamer | 0:7a64fbb4069d | 1384 | if (flags & TCP_SYN) { |
screamer | 0:7a64fbb4069d | 1385 | pcb->ts_recent = ntohl(tsval); |
screamer | 0:7a64fbb4069d | 1386 | pcb->flags |= TF_TIMESTAMP; |
screamer | 0:7a64fbb4069d | 1387 | } else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) { |
screamer | 0:7a64fbb4069d | 1388 | pcb->ts_recent = ntohl(tsval); |
screamer | 0:7a64fbb4069d | 1389 | } |
screamer | 0:7a64fbb4069d | 1390 | /* Advance to next option */ |
screamer | 0:7a64fbb4069d | 1391 | c += 0x0A; |
screamer | 0:7a64fbb4069d | 1392 | break; |
screamer | 0:7a64fbb4069d | 1393 | #endif |
screamer | 0:7a64fbb4069d | 1394 | default: |
screamer | 0:7a64fbb4069d | 1395 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n")); |
screamer | 0:7a64fbb4069d | 1396 | if (opts[c + 1] == 0) { |
screamer | 0:7a64fbb4069d | 1397 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
screamer | 0:7a64fbb4069d | 1398 | /* If the length field is zero, the options are malformed |
screamer | 0:7a64fbb4069d | 1399 | and we don't process them further. */ |
screamer | 0:7a64fbb4069d | 1400 | return; |
screamer | 0:7a64fbb4069d | 1401 | } |
screamer | 0:7a64fbb4069d | 1402 | /* All other options have a length field, so that we easily |
screamer | 0:7a64fbb4069d | 1403 | can skip past them. */ |
screamer | 0:7a64fbb4069d | 1404 | c += opts[c + 1]; |
screamer | 0:7a64fbb4069d | 1405 | } |
screamer | 0:7a64fbb4069d | 1406 | } |
screamer | 0:7a64fbb4069d | 1407 | } |
screamer | 0:7a64fbb4069d | 1408 | } |
screamer | 0:7a64fbb4069d | 1409 | |
screamer | 0:7a64fbb4069d | 1410 | #endif /* LWIP_TCP */ |