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lwip/core/tcp_in.c@0:ac1725ba162c, 2010-11-09 (annotated)
- Committer:
- segundo
- Date:
- Tue Nov 09 20:54:15 2010 +0000
- Revision:
- 0:ac1725ba162c
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
segundo | 0:ac1725ba162c | 1 | /** |
segundo | 0:ac1725ba162c | 2 | * @file |
segundo | 0:ac1725ba162c | 3 | * Transmission Control Protocol, incoming traffic |
segundo | 0:ac1725ba162c | 4 | * |
segundo | 0:ac1725ba162c | 5 | * The input processing functions of the TCP layer. |
segundo | 0:ac1725ba162c | 6 | * |
segundo | 0:ac1725ba162c | 7 | * These functions are generally called in the order (ip_input() ->) |
segundo | 0:ac1725ba162c | 8 | * tcp_input() -> * tcp_process() -> tcp_receive() (-> application). |
segundo | 0:ac1725ba162c | 9 | * |
segundo | 0:ac1725ba162c | 10 | */ |
segundo | 0:ac1725ba162c | 11 | |
segundo | 0:ac1725ba162c | 12 | /* |
segundo | 0:ac1725ba162c | 13 | * Copyright (c) 2001-2004 Swedish Institute of Computer Science. |
segundo | 0:ac1725ba162c | 14 | * All rights reserved. |
segundo | 0:ac1725ba162c | 15 | * |
segundo | 0:ac1725ba162c | 16 | * Redistribution and use in source and binary forms, with or without modification, |
segundo | 0:ac1725ba162c | 17 | * are permitted provided that the following conditions are met: |
segundo | 0:ac1725ba162c | 18 | * |
segundo | 0:ac1725ba162c | 19 | * 1. Redistributions of source code must retain the above copyright notice, |
segundo | 0:ac1725ba162c | 20 | * this list of conditions and the following disclaimer. |
segundo | 0:ac1725ba162c | 21 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
segundo | 0:ac1725ba162c | 22 | * this list of conditions and the following disclaimer in the documentation |
segundo | 0:ac1725ba162c | 23 | * and/or other materials provided with the distribution. |
segundo | 0:ac1725ba162c | 24 | * 3. The name of the author may not be used to endorse or promote products |
segundo | 0:ac1725ba162c | 25 | * derived from this software without specific prior written permission. |
segundo | 0:ac1725ba162c | 26 | * |
segundo | 0:ac1725ba162c | 27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
segundo | 0:ac1725ba162c | 28 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
segundo | 0:ac1725ba162c | 29 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT |
segundo | 0:ac1725ba162c | 30 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
segundo | 0:ac1725ba162c | 31 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT |
segundo | 0:ac1725ba162c | 32 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
segundo | 0:ac1725ba162c | 33 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
segundo | 0:ac1725ba162c | 34 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
segundo | 0:ac1725ba162c | 35 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY |
segundo | 0:ac1725ba162c | 36 | * OF SUCH DAMAGE. |
segundo | 0:ac1725ba162c | 37 | * |
segundo | 0:ac1725ba162c | 38 | * This file is part of the lwIP TCP/IP stack. |
segundo | 0:ac1725ba162c | 39 | * |
segundo | 0:ac1725ba162c | 40 | * Author: Adam Dunkels <adam@sics.se> |
segundo | 0:ac1725ba162c | 41 | * |
segundo | 0:ac1725ba162c | 42 | */ |
segundo | 0:ac1725ba162c | 43 | |
segundo | 0:ac1725ba162c | 44 | #include "lwip/opt.h" |
segundo | 0:ac1725ba162c | 45 | |
segundo | 0:ac1725ba162c | 46 | #if LWIP_TCP /* don't build if not configured for use in lwipopts.h */ |
segundo | 0:ac1725ba162c | 47 | |
segundo | 0:ac1725ba162c | 48 | #include "lwip/tcp_impl.h" |
segundo | 0:ac1725ba162c | 49 | #include "lwip/def.h" |
segundo | 0:ac1725ba162c | 50 | #include "lwip/ip_addr.h" |
segundo | 0:ac1725ba162c | 51 | #include "lwip/netif.h" |
segundo | 0:ac1725ba162c | 52 | #include "lwip/mem.h" |
segundo | 0:ac1725ba162c | 53 | #include "lwip/memp.h" |
segundo | 0:ac1725ba162c | 54 | #include "lwip/inet_chksum.h" |
segundo | 0:ac1725ba162c | 55 | #include "lwip/stats.h" |
segundo | 0:ac1725ba162c | 56 | #include "lwip/snmp.h" |
segundo | 0:ac1725ba162c | 57 | #include "arch/perf.h" |
segundo | 0:ac1725ba162c | 58 | |
segundo | 0:ac1725ba162c | 59 | /* These variables are global to all functions involved in the input |
segundo | 0:ac1725ba162c | 60 | processing of TCP segments. They are set by the tcp_input() |
segundo | 0:ac1725ba162c | 61 | function. */ |
segundo | 0:ac1725ba162c | 62 | static struct tcp_seg inseg; |
segundo | 0:ac1725ba162c | 63 | static struct tcp_hdr *tcphdr; |
segundo | 0:ac1725ba162c | 64 | static struct ip_hdr *iphdr; |
segundo | 0:ac1725ba162c | 65 | static u32_t seqno, ackno; |
segundo | 0:ac1725ba162c | 66 | static u8_t flags; |
segundo | 0:ac1725ba162c | 67 | static u16_t tcplen; |
segundo | 0:ac1725ba162c | 68 | |
segundo | 0:ac1725ba162c | 69 | static u8_t recv_flags; |
segundo | 0:ac1725ba162c | 70 | static struct pbuf *recv_data; |
segundo | 0:ac1725ba162c | 71 | |
segundo | 0:ac1725ba162c | 72 | struct tcp_pcb *tcp_input_pcb; |
segundo | 0:ac1725ba162c | 73 | |
segundo | 0:ac1725ba162c | 74 | /* Forward declarations. */ |
segundo | 0:ac1725ba162c | 75 | static err_t tcp_process(struct tcp_pcb *pcb); |
segundo | 0:ac1725ba162c | 76 | static void tcp_receive(struct tcp_pcb *pcb); |
segundo | 0:ac1725ba162c | 77 | static void tcp_parseopt(struct tcp_pcb *pcb); |
segundo | 0:ac1725ba162c | 78 | |
segundo | 0:ac1725ba162c | 79 | static err_t tcp_listen_input(struct tcp_pcb_listen *pcb); |
segundo | 0:ac1725ba162c | 80 | static err_t tcp_timewait_input(struct tcp_pcb *pcb); |
segundo | 0:ac1725ba162c | 81 | |
segundo | 0:ac1725ba162c | 82 | /** |
segundo | 0:ac1725ba162c | 83 | * The initial input processing of TCP. It verifies the TCP header, demultiplexes |
segundo | 0:ac1725ba162c | 84 | * the segment between the PCBs and passes it on to tcp_process(), which implements |
segundo | 0:ac1725ba162c | 85 | * the TCP finite state machine. This function is called by the IP layer (in |
segundo | 0:ac1725ba162c | 86 | * ip_input()). |
segundo | 0:ac1725ba162c | 87 | * |
segundo | 0:ac1725ba162c | 88 | * @param p received TCP segment to process (p->payload pointing to the IP header) |
segundo | 0:ac1725ba162c | 89 | * @param inp network interface on which this segment was received |
segundo | 0:ac1725ba162c | 90 | */ |
segundo | 0:ac1725ba162c | 91 | void |
segundo | 0:ac1725ba162c | 92 | tcp_input(struct pbuf *p, struct netif *inp) |
segundo | 0:ac1725ba162c | 93 | { |
segundo | 0:ac1725ba162c | 94 | struct tcp_pcb *pcb, *prev; |
segundo | 0:ac1725ba162c | 95 | struct tcp_pcb_listen *lpcb; |
segundo | 0:ac1725ba162c | 96 | #if SO_REUSE |
segundo | 0:ac1725ba162c | 97 | struct tcp_pcb *lpcb_prev = NULL; |
segundo | 0:ac1725ba162c | 98 | struct tcp_pcb_listen *lpcb_any = NULL; |
segundo | 0:ac1725ba162c | 99 | #endif /* SO_REUSE */ |
segundo | 0:ac1725ba162c | 100 | u8_t hdrlen; |
segundo | 0:ac1725ba162c | 101 | err_t err; |
segundo | 0:ac1725ba162c | 102 | |
segundo | 0:ac1725ba162c | 103 | PERF_START; |
segundo | 0:ac1725ba162c | 104 | |
segundo | 0:ac1725ba162c | 105 | TCP_STATS_INC(tcp.recv); |
segundo | 0:ac1725ba162c | 106 | snmp_inc_tcpinsegs(); |
segundo | 0:ac1725ba162c | 107 | |
segundo | 0:ac1725ba162c | 108 | iphdr = (struct ip_hdr *)p->payload; |
segundo | 0:ac1725ba162c | 109 | tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4); |
segundo | 0:ac1725ba162c | 110 | |
segundo | 0:ac1725ba162c | 111 | #if TCP_INPUT_DEBUG |
segundo | 0:ac1725ba162c | 112 | tcp_debug_print(tcphdr); |
segundo | 0:ac1725ba162c | 113 | #endif |
segundo | 0:ac1725ba162c | 114 | |
segundo | 0:ac1725ba162c | 115 | /* remove header from payload */ |
segundo | 0:ac1725ba162c | 116 | if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) { |
segundo | 0:ac1725ba162c | 117 | /* drop short packets */ |
segundo | 0:ac1725ba162c | 118 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len)); |
segundo | 0:ac1725ba162c | 119 | TCP_STATS_INC(tcp.lenerr); |
segundo | 0:ac1725ba162c | 120 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 121 | snmp_inc_tcpinerrs(); |
segundo | 0:ac1725ba162c | 122 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 123 | return; |
segundo | 0:ac1725ba162c | 124 | } |
segundo | 0:ac1725ba162c | 125 | |
segundo | 0:ac1725ba162c | 126 | /* Don't even process incoming broadcasts/multicasts. */ |
segundo | 0:ac1725ba162c | 127 | if (ip_addr_isbroadcast(¤t_iphdr_dest, inp) || |
segundo | 0:ac1725ba162c | 128 | ip_addr_ismulticast(¤t_iphdr_dest)) { |
segundo | 0:ac1725ba162c | 129 | TCP_STATS_INC(tcp.proterr); |
segundo | 0:ac1725ba162c | 130 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 131 | snmp_inc_tcpinerrs(); |
segundo | 0:ac1725ba162c | 132 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 133 | return; |
segundo | 0:ac1725ba162c | 134 | } |
segundo | 0:ac1725ba162c | 135 | |
segundo | 0:ac1725ba162c | 136 | #if CHECKSUM_CHECK_TCP |
segundo | 0:ac1725ba162c | 137 | /* Verify TCP checksum. */ |
segundo | 0:ac1725ba162c | 138 | if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(), |
segundo | 0:ac1725ba162c | 139 | IP_PROTO_TCP, p->tot_len) != 0) { |
segundo | 0:ac1725ba162c | 140 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n", |
segundo | 0:ac1725ba162c | 141 | inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(), |
segundo | 0:ac1725ba162c | 142 | IP_PROTO_TCP, p->tot_len))); |
segundo | 0:ac1725ba162c | 143 | #if TCP_DEBUG |
segundo | 0:ac1725ba162c | 144 | tcp_debug_print(tcphdr); |
segundo | 0:ac1725ba162c | 145 | #endif /* TCP_DEBUG */ |
segundo | 0:ac1725ba162c | 146 | TCP_STATS_INC(tcp.chkerr); |
segundo | 0:ac1725ba162c | 147 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 148 | snmp_inc_tcpinerrs(); |
segundo | 0:ac1725ba162c | 149 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 150 | return; |
segundo | 0:ac1725ba162c | 151 | } |
segundo | 0:ac1725ba162c | 152 | #endif |
segundo | 0:ac1725ba162c | 153 | |
segundo | 0:ac1725ba162c | 154 | /* Move the payload pointer in the pbuf so that it points to the |
segundo | 0:ac1725ba162c | 155 | TCP data instead of the TCP header. */ |
segundo | 0:ac1725ba162c | 156 | hdrlen = TCPH_HDRLEN(tcphdr); |
segundo | 0:ac1725ba162c | 157 | if(pbuf_header(p, -(hdrlen * 4))){ |
segundo | 0:ac1725ba162c | 158 | /* drop short packets */ |
segundo | 0:ac1725ba162c | 159 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n")); |
segundo | 0:ac1725ba162c | 160 | TCP_STATS_INC(tcp.lenerr); |
segundo | 0:ac1725ba162c | 161 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 162 | snmp_inc_tcpinerrs(); |
segundo | 0:ac1725ba162c | 163 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 164 | return; |
segundo | 0:ac1725ba162c | 165 | } |
segundo | 0:ac1725ba162c | 166 | |
segundo | 0:ac1725ba162c | 167 | /* Convert fields in TCP header to host byte order. */ |
segundo | 0:ac1725ba162c | 168 | tcphdr->src = ntohs(tcphdr->src); |
segundo | 0:ac1725ba162c | 169 | tcphdr->dest = ntohs(tcphdr->dest); |
segundo | 0:ac1725ba162c | 170 | seqno = tcphdr->seqno = ntohl(tcphdr->seqno); |
segundo | 0:ac1725ba162c | 171 | ackno = tcphdr->ackno = ntohl(tcphdr->ackno); |
segundo | 0:ac1725ba162c | 172 | tcphdr->wnd = ntohs(tcphdr->wnd); |
segundo | 0:ac1725ba162c | 173 | |
segundo | 0:ac1725ba162c | 174 | flags = TCPH_FLAGS(tcphdr); |
segundo | 0:ac1725ba162c | 175 | tcplen = p->tot_len + ((flags & (TCP_FIN | TCP_SYN)) ? 1 : 0); |
segundo | 0:ac1725ba162c | 176 | |
segundo | 0:ac1725ba162c | 177 | /* Demultiplex an incoming segment. First, we check if it is destined |
segundo | 0:ac1725ba162c | 178 | for an active connection. */ |
segundo | 0:ac1725ba162c | 179 | prev = NULL; |
segundo | 0:ac1725ba162c | 180 | |
segundo | 0:ac1725ba162c | 181 | |
segundo | 0:ac1725ba162c | 182 | for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) { |
segundo | 0:ac1725ba162c | 183 | LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED); |
segundo | 0:ac1725ba162c | 184 | LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT); |
segundo | 0:ac1725ba162c | 185 | LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN); |
segundo | 0:ac1725ba162c | 186 | if (pcb->remote_port == tcphdr->src && |
segundo | 0:ac1725ba162c | 187 | pcb->local_port == tcphdr->dest && |
segundo | 0:ac1725ba162c | 188 | ip_addr_cmp(&(pcb->remote_ip), ¤t_iphdr_src) && |
segundo | 0:ac1725ba162c | 189 | ip_addr_cmp(&(pcb->local_ip), ¤t_iphdr_dest)) { |
segundo | 0:ac1725ba162c | 190 | |
segundo | 0:ac1725ba162c | 191 | /* Move this PCB to the front of the list so that subsequent |
segundo | 0:ac1725ba162c | 192 | lookups will be faster (we exploit locality in TCP segment |
segundo | 0:ac1725ba162c | 193 | arrivals). */ |
segundo | 0:ac1725ba162c | 194 | LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb); |
segundo | 0:ac1725ba162c | 195 | if (prev != NULL) { |
segundo | 0:ac1725ba162c | 196 | prev->next = pcb->next; |
segundo | 0:ac1725ba162c | 197 | pcb->next = tcp_active_pcbs; |
segundo | 0:ac1725ba162c | 198 | tcp_active_pcbs = pcb; |
segundo | 0:ac1725ba162c | 199 | } |
segundo | 0:ac1725ba162c | 200 | LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb); |
segundo | 0:ac1725ba162c | 201 | break; |
segundo | 0:ac1725ba162c | 202 | } |
segundo | 0:ac1725ba162c | 203 | prev = pcb; |
segundo | 0:ac1725ba162c | 204 | } |
segundo | 0:ac1725ba162c | 205 | |
segundo | 0:ac1725ba162c | 206 | if (pcb == NULL) { |
segundo | 0:ac1725ba162c | 207 | /* If it did not go to an active connection, we check the connections |
segundo | 0:ac1725ba162c | 208 | in the TIME-WAIT state. */ |
segundo | 0:ac1725ba162c | 209 | for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) { |
segundo | 0:ac1725ba162c | 210 | LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT); |
segundo | 0:ac1725ba162c | 211 | if (pcb->remote_port == tcphdr->src && |
segundo | 0:ac1725ba162c | 212 | pcb->local_port == tcphdr->dest && |
segundo | 0:ac1725ba162c | 213 | ip_addr_cmp(&(pcb->remote_ip), ¤t_iphdr_src) && |
segundo | 0:ac1725ba162c | 214 | ip_addr_cmp(&(pcb->local_ip), ¤t_iphdr_dest)) { |
segundo | 0:ac1725ba162c | 215 | /* We don't really care enough to move this PCB to the front |
segundo | 0:ac1725ba162c | 216 | of the list since we are not very likely to receive that |
segundo | 0:ac1725ba162c | 217 | many segments for connections in TIME-WAIT. */ |
segundo | 0:ac1725ba162c | 218 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n")); |
segundo | 0:ac1725ba162c | 219 | tcp_timewait_input(pcb); |
segundo | 0:ac1725ba162c | 220 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 221 | return; |
segundo | 0:ac1725ba162c | 222 | } |
segundo | 0:ac1725ba162c | 223 | } |
segundo | 0:ac1725ba162c | 224 | |
segundo | 0:ac1725ba162c | 225 | /* Finally, if we still did not get a match, we check all PCBs that |
segundo | 0:ac1725ba162c | 226 | are LISTENing for incoming connections. */ |
segundo | 0:ac1725ba162c | 227 | prev = NULL; |
segundo | 0:ac1725ba162c | 228 | for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) { |
segundo | 0:ac1725ba162c | 229 | if (lpcb->local_port == tcphdr->dest) { |
segundo | 0:ac1725ba162c | 230 | #if SO_REUSE |
segundo | 0:ac1725ba162c | 231 | if (ip_addr_cmp(&(lpcb->local_ip), ¤t_iphdr_dest)) { |
segundo | 0:ac1725ba162c | 232 | /* found an exact match */ |
segundo | 0:ac1725ba162c | 233 | break; |
segundo | 0:ac1725ba162c | 234 | } else if(ip_addr_isany(&(lpcb->local_ip))) { |
segundo | 0:ac1725ba162c | 235 | /* found an ANY-match */ |
segundo | 0:ac1725ba162c | 236 | lpcb_any = lpcb; |
segundo | 0:ac1725ba162c | 237 | lpcb_prev = prev; |
segundo | 0:ac1725ba162c | 238 | } |
segundo | 0:ac1725ba162c | 239 | #else /* SO_REUSE */ |
segundo | 0:ac1725ba162c | 240 | if (ip_addr_cmp(&(lpcb->local_ip), ¤t_iphdr_dest) || |
segundo | 0:ac1725ba162c | 241 | ip_addr_isany(&(lpcb->local_ip))) { |
segundo | 0:ac1725ba162c | 242 | /* found a match */ |
segundo | 0:ac1725ba162c | 243 | break; |
segundo | 0:ac1725ba162c | 244 | } |
segundo | 0:ac1725ba162c | 245 | #endif /* SO_REUSE */ |
segundo | 0:ac1725ba162c | 246 | } |
segundo | 0:ac1725ba162c | 247 | prev = (struct tcp_pcb *)lpcb; |
segundo | 0:ac1725ba162c | 248 | } |
segundo | 0:ac1725ba162c | 249 | #if SO_REUSE |
segundo | 0:ac1725ba162c | 250 | /* first try specific local IP */ |
segundo | 0:ac1725ba162c | 251 | if (lpcb == NULL) { |
segundo | 0:ac1725ba162c | 252 | /* only pass to ANY if no specific local IP has been found */ |
segundo | 0:ac1725ba162c | 253 | lpcb = lpcb_any; |
segundo | 0:ac1725ba162c | 254 | prev = lpcb_prev; |
segundo | 0:ac1725ba162c | 255 | } |
segundo | 0:ac1725ba162c | 256 | #endif /* SO_REUSE */ |
segundo | 0:ac1725ba162c | 257 | if (lpcb != NULL) { |
segundo | 0:ac1725ba162c | 258 | /* Move this PCB to the front of the list so that subsequent |
segundo | 0:ac1725ba162c | 259 | lookups will be faster (we exploit locality in TCP segment |
segundo | 0:ac1725ba162c | 260 | arrivals). */ |
segundo | 0:ac1725ba162c | 261 | if (prev != NULL) { |
segundo | 0:ac1725ba162c | 262 | ((struct tcp_pcb_listen *)prev)->next = lpcb->next; |
segundo | 0:ac1725ba162c | 263 | /* our successor is the remainder of the listening list */ |
segundo | 0:ac1725ba162c | 264 | lpcb->next = tcp_listen_pcbs.listen_pcbs; |
segundo | 0:ac1725ba162c | 265 | /* put this listening pcb at the head of the listening list */ |
segundo | 0:ac1725ba162c | 266 | tcp_listen_pcbs.listen_pcbs = lpcb; |
segundo | 0:ac1725ba162c | 267 | } |
segundo | 0:ac1725ba162c | 268 | |
segundo | 0:ac1725ba162c | 269 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n")); |
segundo | 0:ac1725ba162c | 270 | tcp_listen_input(lpcb); |
segundo | 0:ac1725ba162c | 271 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 272 | return; |
segundo | 0:ac1725ba162c | 273 | } |
segundo | 0:ac1725ba162c | 274 | } |
segundo | 0:ac1725ba162c | 275 | |
segundo | 0:ac1725ba162c | 276 | #if TCP_INPUT_DEBUG |
segundo | 0:ac1725ba162c | 277 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags ")); |
segundo | 0:ac1725ba162c | 278 | tcp_debug_print_flags(TCPH_FLAGS(tcphdr)); |
segundo | 0:ac1725ba162c | 279 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n")); |
segundo | 0:ac1725ba162c | 280 | #endif /* TCP_INPUT_DEBUG */ |
segundo | 0:ac1725ba162c | 281 | |
segundo | 0:ac1725ba162c | 282 | |
segundo | 0:ac1725ba162c | 283 | if (pcb != NULL) { |
segundo | 0:ac1725ba162c | 284 | /* The incoming segment belongs to a connection. */ |
segundo | 0:ac1725ba162c | 285 | #if TCP_INPUT_DEBUG |
segundo | 0:ac1725ba162c | 286 | #if TCP_DEBUG |
segundo | 0:ac1725ba162c | 287 | tcp_debug_print_state(pcb->state); |
segundo | 0:ac1725ba162c | 288 | #endif /* TCP_DEBUG */ |
segundo | 0:ac1725ba162c | 289 | #endif /* TCP_INPUT_DEBUG */ |
segundo | 0:ac1725ba162c | 290 | |
segundo | 0:ac1725ba162c | 291 | /* Set up a tcp_seg structure. */ |
segundo | 0:ac1725ba162c | 292 | inseg.next = NULL; |
segundo | 0:ac1725ba162c | 293 | inseg.len = p->tot_len; |
segundo | 0:ac1725ba162c | 294 | inseg.dataptr = p->payload; |
segundo | 0:ac1725ba162c | 295 | inseg.p = p; |
segundo | 0:ac1725ba162c | 296 | inseg.tcphdr = tcphdr; |
segundo | 0:ac1725ba162c | 297 | |
segundo | 0:ac1725ba162c | 298 | recv_data = NULL; |
segundo | 0:ac1725ba162c | 299 | recv_flags = 0; |
segundo | 0:ac1725ba162c | 300 | |
segundo | 0:ac1725ba162c | 301 | /* If there is data which was previously "refused" by upper layer */ |
segundo | 0:ac1725ba162c | 302 | if (pcb->refused_data != NULL) { |
segundo | 0:ac1725ba162c | 303 | /* Notify again application with data previously received. */ |
segundo | 0:ac1725ba162c | 304 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n")); |
segundo | 0:ac1725ba162c | 305 | TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err); |
segundo | 0:ac1725ba162c | 306 | if (err == ERR_OK) { |
segundo | 0:ac1725ba162c | 307 | pcb->refused_data = NULL; |
segundo | 0:ac1725ba162c | 308 | } else { |
segundo | 0:ac1725ba162c | 309 | /* if err == ERR_ABRT, 'pcb' is already deallocated */ |
segundo | 0:ac1725ba162c | 310 | /* drop incoming packets, because pcb is "full" */ |
segundo | 0:ac1725ba162c | 311 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n")); |
segundo | 0:ac1725ba162c | 312 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 313 | snmp_inc_tcpinerrs(); |
segundo | 0:ac1725ba162c | 314 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 315 | return; |
segundo | 0:ac1725ba162c | 316 | } |
segundo | 0:ac1725ba162c | 317 | } |
segundo | 0:ac1725ba162c | 318 | tcp_input_pcb = pcb; |
segundo | 0:ac1725ba162c | 319 | err = tcp_process(pcb); |
segundo | 0:ac1725ba162c | 320 | /* A return value of ERR_ABRT means that tcp_abort() was called |
segundo | 0:ac1725ba162c | 321 | and that the pcb has been freed. If so, we don't do anything. */ |
segundo | 0:ac1725ba162c | 322 | if (err != ERR_ABRT) { |
segundo | 0:ac1725ba162c | 323 | if (recv_flags & TF_RESET) { |
segundo | 0:ac1725ba162c | 324 | /* TF_RESET means that the connection was reset by the other |
segundo | 0:ac1725ba162c | 325 | end. We then call the error callback to inform the |
segundo | 0:ac1725ba162c | 326 | application that the connection is dead before we |
segundo | 0:ac1725ba162c | 327 | deallocate the PCB. */ |
segundo | 0:ac1725ba162c | 328 | TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST); |
segundo | 0:ac1725ba162c | 329 | tcp_pcb_remove(&tcp_active_pcbs, pcb); |
segundo | 0:ac1725ba162c | 330 | memp_free(MEMP_TCP_PCB, pcb); |
segundo | 0:ac1725ba162c | 331 | } else if (recv_flags & TF_CLOSED) { |
segundo | 0:ac1725ba162c | 332 | /* The connection has been closed and we will deallocate the |
segundo | 0:ac1725ba162c | 333 | PCB. */ |
segundo | 0:ac1725ba162c | 334 | tcp_pcb_remove(&tcp_active_pcbs, pcb); |
segundo | 0:ac1725ba162c | 335 | memp_free(MEMP_TCP_PCB, pcb); |
segundo | 0:ac1725ba162c | 336 | } else { |
segundo | 0:ac1725ba162c | 337 | err = ERR_OK; |
segundo | 0:ac1725ba162c | 338 | /* If the application has registered a "sent" function to be |
segundo | 0:ac1725ba162c | 339 | called when new send buffer space is available, we call it |
segundo | 0:ac1725ba162c | 340 | now. */ |
segundo | 0:ac1725ba162c | 341 | if (pcb->acked > 0) { |
segundo | 0:ac1725ba162c | 342 | TCP_EVENT_SENT(pcb, pcb->acked, err); |
segundo | 0:ac1725ba162c | 343 | if (err == ERR_ABRT) { |
segundo | 0:ac1725ba162c | 344 | goto aborted; |
segundo | 0:ac1725ba162c | 345 | } |
segundo | 0:ac1725ba162c | 346 | } |
segundo | 0:ac1725ba162c | 347 | |
segundo | 0:ac1725ba162c | 348 | if (recv_data != NULL) { |
segundo | 0:ac1725ba162c | 349 | if (pcb->flags & TF_RXCLOSED) { |
segundo | 0:ac1725ba162c | 350 | /* received data although already closed -> abort (send RST) to |
segundo | 0:ac1725ba162c | 351 | notify the remote host that not all data has been processed */ |
segundo | 0:ac1725ba162c | 352 | pbuf_free(recv_data); |
segundo | 0:ac1725ba162c | 353 | tcp_abort(pcb); |
segundo | 0:ac1725ba162c | 354 | goto aborted; |
segundo | 0:ac1725ba162c | 355 | } |
segundo | 0:ac1725ba162c | 356 | if (flags & TCP_PSH) { |
segundo | 0:ac1725ba162c | 357 | recv_data->flags |= PBUF_FLAG_PUSH; |
segundo | 0:ac1725ba162c | 358 | } |
segundo | 0:ac1725ba162c | 359 | |
segundo | 0:ac1725ba162c | 360 | /* Notify application that data has been received. */ |
segundo | 0:ac1725ba162c | 361 | TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err); |
segundo | 0:ac1725ba162c | 362 | if (err == ERR_ABRT) { |
segundo | 0:ac1725ba162c | 363 | goto aborted; |
segundo | 0:ac1725ba162c | 364 | } |
segundo | 0:ac1725ba162c | 365 | |
segundo | 0:ac1725ba162c | 366 | /* If the upper layer can't receive this data, store it */ |
segundo | 0:ac1725ba162c | 367 | if (err != ERR_OK) { |
segundo | 0:ac1725ba162c | 368 | pcb->refused_data = recv_data; |
segundo | 0:ac1725ba162c | 369 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n")); |
segundo | 0:ac1725ba162c | 370 | } |
segundo | 0:ac1725ba162c | 371 | } |
segundo | 0:ac1725ba162c | 372 | |
segundo | 0:ac1725ba162c | 373 | /* If a FIN segment was received, we call the callback |
segundo | 0:ac1725ba162c | 374 | function with a NULL buffer to indicate EOF. */ |
segundo | 0:ac1725ba162c | 375 | if (recv_flags & TF_GOT_FIN) { |
segundo | 0:ac1725ba162c | 376 | /* correct rcv_wnd as the application won't call tcp_recved() |
segundo | 0:ac1725ba162c | 377 | for the FIN's seqno */ |
segundo | 0:ac1725ba162c | 378 | if (pcb->rcv_wnd != TCP_WND) { |
segundo | 0:ac1725ba162c | 379 | pcb->rcv_wnd++; |
segundo | 0:ac1725ba162c | 380 | } |
segundo | 0:ac1725ba162c | 381 | TCP_EVENT_CLOSED(pcb, err); |
segundo | 0:ac1725ba162c | 382 | if (err == ERR_ABRT) { |
segundo | 0:ac1725ba162c | 383 | goto aborted; |
segundo | 0:ac1725ba162c | 384 | } |
segundo | 0:ac1725ba162c | 385 | } |
segundo | 0:ac1725ba162c | 386 | |
segundo | 0:ac1725ba162c | 387 | tcp_input_pcb = NULL; |
segundo | 0:ac1725ba162c | 388 | /* Try to send something out. */ |
segundo | 0:ac1725ba162c | 389 | tcp_output(pcb); |
segundo | 0:ac1725ba162c | 390 | #if TCP_INPUT_DEBUG |
segundo | 0:ac1725ba162c | 391 | #if TCP_DEBUG |
segundo | 0:ac1725ba162c | 392 | tcp_debug_print_state(pcb->state); |
segundo | 0:ac1725ba162c | 393 | #endif /* TCP_DEBUG */ |
segundo | 0:ac1725ba162c | 394 | #endif /* TCP_INPUT_DEBUG */ |
segundo | 0:ac1725ba162c | 395 | } |
segundo | 0:ac1725ba162c | 396 | } |
segundo | 0:ac1725ba162c | 397 | /* Jump target if pcb has been aborted in a callback (by calling tcp_abort()). |
segundo | 0:ac1725ba162c | 398 | Below this line, 'pcb' may not be dereferenced! */ |
segundo | 0:ac1725ba162c | 399 | aborted: |
segundo | 0:ac1725ba162c | 400 | tcp_input_pcb = NULL; |
segundo | 0:ac1725ba162c | 401 | recv_data = NULL; |
segundo | 0:ac1725ba162c | 402 | |
segundo | 0:ac1725ba162c | 403 | /* give up our reference to inseg.p */ |
segundo | 0:ac1725ba162c | 404 | if (inseg.p != NULL) |
segundo | 0:ac1725ba162c | 405 | { |
segundo | 0:ac1725ba162c | 406 | pbuf_free(inseg.p); |
segundo | 0:ac1725ba162c | 407 | inseg.p = NULL; |
segundo | 0:ac1725ba162c | 408 | } |
segundo | 0:ac1725ba162c | 409 | } else { |
segundo | 0:ac1725ba162c | 410 | |
segundo | 0:ac1725ba162c | 411 | /* If no matching PCB was found, send a TCP RST (reset) to the |
segundo | 0:ac1725ba162c | 412 | sender. */ |
segundo | 0:ac1725ba162c | 413 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n")); |
segundo | 0:ac1725ba162c | 414 | if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) { |
segundo | 0:ac1725ba162c | 415 | TCP_STATS_INC(tcp.proterr); |
segundo | 0:ac1725ba162c | 416 | TCP_STATS_INC(tcp.drop); |
segundo | 0:ac1725ba162c | 417 | tcp_rst(ackno, seqno + tcplen, |
segundo | 0:ac1725ba162c | 418 | ip_current_dest_addr(), ip_current_src_addr(), |
segundo | 0:ac1725ba162c | 419 | tcphdr->dest, tcphdr->src); |
segundo | 0:ac1725ba162c | 420 | } |
segundo | 0:ac1725ba162c | 421 | pbuf_free(p); |
segundo | 0:ac1725ba162c | 422 | } |
segundo | 0:ac1725ba162c | 423 | |
segundo | 0:ac1725ba162c | 424 | LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane()); |
segundo | 0:ac1725ba162c | 425 | PERF_STOP("tcp_input"); |
segundo | 0:ac1725ba162c | 426 | } |
segundo | 0:ac1725ba162c | 427 | |
segundo | 0:ac1725ba162c | 428 | /** |
segundo | 0:ac1725ba162c | 429 | * Called by tcp_input() when a segment arrives for a listening |
segundo | 0:ac1725ba162c | 430 | * connection (from tcp_input()). |
segundo | 0:ac1725ba162c | 431 | * |
segundo | 0:ac1725ba162c | 432 | * @param pcb the tcp_pcb_listen for which a segment arrived |
segundo | 0:ac1725ba162c | 433 | * @return ERR_OK if the segment was processed |
segundo | 0:ac1725ba162c | 434 | * another err_t on error |
segundo | 0:ac1725ba162c | 435 | * |
segundo | 0:ac1725ba162c | 436 | * @note the return value is not (yet?) used in tcp_input() |
segundo | 0:ac1725ba162c | 437 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
segundo | 0:ac1725ba162c | 438 | * involved is passed as a parameter to this function |
segundo | 0:ac1725ba162c | 439 | */ |
segundo | 0:ac1725ba162c | 440 | static err_t |
segundo | 0:ac1725ba162c | 441 | tcp_listen_input(struct tcp_pcb_listen *pcb) |
segundo | 0:ac1725ba162c | 442 | { |
segundo | 0:ac1725ba162c | 443 | struct tcp_pcb *npcb; |
segundo | 0:ac1725ba162c | 444 | err_t rc; |
segundo | 0:ac1725ba162c | 445 | |
segundo | 0:ac1725ba162c | 446 | /* In the LISTEN state, we check for incoming SYN segments, |
segundo | 0:ac1725ba162c | 447 | creates a new PCB, and responds with a SYN|ACK. */ |
segundo | 0:ac1725ba162c | 448 | if (flags & TCP_ACK) { |
segundo | 0:ac1725ba162c | 449 | /* For incoming segments with the ACK flag set, respond with a |
segundo | 0:ac1725ba162c | 450 | RST. */ |
segundo | 0:ac1725ba162c | 451 | LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n")); |
segundo | 0:ac1725ba162c | 452 | tcp_rst(ackno + 1, seqno + tcplen, |
segundo | 0:ac1725ba162c | 453 | ip_current_dest_addr(), ip_current_src_addr(), |
segundo | 0:ac1725ba162c | 454 | tcphdr->dest, tcphdr->src); |
segundo | 0:ac1725ba162c | 455 | } else if (flags & TCP_SYN) { |
segundo | 0:ac1725ba162c | 456 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest)); |
segundo | 0:ac1725ba162c | 457 | #if TCP_LISTEN_BACKLOG |
segundo | 0:ac1725ba162c | 458 | if (pcb->accepts_pending >= pcb->backlog) { |
segundo | 0:ac1725ba162c | 459 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest)); |
segundo | 0:ac1725ba162c | 460 | return ERR_ABRT; |
segundo | 0:ac1725ba162c | 461 | } |
segundo | 0:ac1725ba162c | 462 | #endif /* TCP_LISTEN_BACKLOG */ |
segundo | 0:ac1725ba162c | 463 | npcb = tcp_alloc(pcb->prio); |
segundo | 0:ac1725ba162c | 464 | /* If a new PCB could not be created (probably due to lack of memory), |
segundo | 0:ac1725ba162c | 465 | we don't do anything, but rely on the sender will retransmit the |
segundo | 0:ac1725ba162c | 466 | SYN at a time when we have more memory available. */ |
segundo | 0:ac1725ba162c | 467 | if (npcb == NULL) { |
segundo | 0:ac1725ba162c | 468 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n")); |
segundo | 0:ac1725ba162c | 469 | TCP_STATS_INC(tcp.memerr); |
segundo | 0:ac1725ba162c | 470 | return ERR_MEM; |
segundo | 0:ac1725ba162c | 471 | } |
segundo | 0:ac1725ba162c | 472 | #if TCP_LISTEN_BACKLOG |
segundo | 0:ac1725ba162c | 473 | pcb->accepts_pending++; |
segundo | 0:ac1725ba162c | 474 | #endif /* TCP_LISTEN_BACKLOG */ |
segundo | 0:ac1725ba162c | 475 | /* Set up the new PCB. */ |
segundo | 0:ac1725ba162c | 476 | ip_addr_copy(npcb->local_ip, current_iphdr_dest); |
segundo | 0:ac1725ba162c | 477 | npcb->local_port = pcb->local_port; |
segundo | 0:ac1725ba162c | 478 | ip_addr_copy(npcb->remote_ip, current_iphdr_src); |
segundo | 0:ac1725ba162c | 479 | npcb->remote_port = tcphdr->src; |
segundo | 0:ac1725ba162c | 480 | npcb->state = SYN_RCVD; |
segundo | 0:ac1725ba162c | 481 | npcb->rcv_nxt = seqno + 1; |
segundo | 0:ac1725ba162c | 482 | npcb->rcv_ann_right_edge = npcb->rcv_nxt; |
segundo | 0:ac1725ba162c | 483 | npcb->snd_wnd = tcphdr->wnd; |
segundo | 0:ac1725ba162c | 484 | npcb->ssthresh = npcb->snd_wnd; |
segundo | 0:ac1725ba162c | 485 | npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */ |
segundo | 0:ac1725ba162c | 486 | npcb->callback_arg = pcb->callback_arg; |
segundo | 0:ac1725ba162c | 487 | #if LWIP_CALLBACK_API |
segundo | 0:ac1725ba162c | 488 | npcb->accept = pcb->accept; |
segundo | 0:ac1725ba162c | 489 | #endif /* LWIP_CALLBACK_API */ |
segundo | 0:ac1725ba162c | 490 | /* inherit socket options */ |
segundo | 0:ac1725ba162c | 491 | npcb->so_options = pcb->so_options & SOF_INHERITED; |
segundo | 0:ac1725ba162c | 492 | /* Register the new PCB so that we can begin receiving segments |
segundo | 0:ac1725ba162c | 493 | for it. */ |
segundo | 0:ac1725ba162c | 494 | TCP_REG(&tcp_active_pcbs, npcb); |
segundo | 0:ac1725ba162c | 495 | |
segundo | 0:ac1725ba162c | 496 | /* Parse any options in the SYN. */ |
segundo | 0:ac1725ba162c | 497 | tcp_parseopt(npcb); |
segundo | 0:ac1725ba162c | 498 | #if TCP_CALCULATE_EFF_SEND_MSS |
segundo | 0:ac1725ba162c | 499 | npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip)); |
segundo | 0:ac1725ba162c | 500 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */ |
segundo | 0:ac1725ba162c | 501 | |
segundo | 0:ac1725ba162c | 502 | snmp_inc_tcppassiveopens(); |
segundo | 0:ac1725ba162c | 503 | |
segundo | 0:ac1725ba162c | 504 | /* Send a SYN|ACK together with the MSS option. */ |
segundo | 0:ac1725ba162c | 505 | rc = tcp_enqueue_flags(npcb, TCP_SYN | TCP_ACK); |
segundo | 0:ac1725ba162c | 506 | if (rc != ERR_OK) { |
segundo | 0:ac1725ba162c | 507 | tcp_abandon(npcb, 0); |
segundo | 0:ac1725ba162c | 508 | return rc; |
segundo | 0:ac1725ba162c | 509 | } |
segundo | 0:ac1725ba162c | 510 | return tcp_output(npcb); |
segundo | 0:ac1725ba162c | 511 | } |
segundo | 0:ac1725ba162c | 512 | return ERR_OK; |
segundo | 0:ac1725ba162c | 513 | } |
segundo | 0:ac1725ba162c | 514 | |
segundo | 0:ac1725ba162c | 515 | /** |
segundo | 0:ac1725ba162c | 516 | * Called by tcp_input() when a segment arrives for a connection in |
segundo | 0:ac1725ba162c | 517 | * TIME_WAIT. |
segundo | 0:ac1725ba162c | 518 | * |
segundo | 0:ac1725ba162c | 519 | * @param pcb the tcp_pcb for which a segment arrived |
segundo | 0:ac1725ba162c | 520 | * |
segundo | 0:ac1725ba162c | 521 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
segundo | 0:ac1725ba162c | 522 | * involved is passed as a parameter to this function |
segundo | 0:ac1725ba162c | 523 | */ |
segundo | 0:ac1725ba162c | 524 | static err_t |
segundo | 0:ac1725ba162c | 525 | tcp_timewait_input(struct tcp_pcb *pcb) |
segundo | 0:ac1725ba162c | 526 | { |
segundo | 0:ac1725ba162c | 527 | /* RFC 1337: in TIME_WAIT, ignore RST and ACK FINs + any 'acceptable' segments */ |
segundo | 0:ac1725ba162c | 528 | /* RFC 793 3.9 Event Processing - Segment Arrives: |
segundo | 0:ac1725ba162c | 529 | * - first check sequence number - we skip that one in TIME_WAIT (always |
segundo | 0:ac1725ba162c | 530 | * acceptable since we only send ACKs) |
segundo | 0:ac1725ba162c | 531 | * - second check the RST bit (... return) */ |
segundo | 0:ac1725ba162c | 532 | if (flags & TCP_RST) { |
segundo | 0:ac1725ba162c | 533 | return ERR_OK; |
segundo | 0:ac1725ba162c | 534 | } |
segundo | 0:ac1725ba162c | 535 | /* - fourth, check the SYN bit, */ |
segundo | 0:ac1725ba162c | 536 | if (flags & TCP_SYN) { |
segundo | 0:ac1725ba162c | 537 | /* If an incoming segment is not acceptable, an acknowledgment |
segundo | 0:ac1725ba162c | 538 | should be sent in reply */ |
segundo | 0:ac1725ba162c | 539 | if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) { |
segundo | 0:ac1725ba162c | 540 | /* If the SYN is in the window it is an error, send a reset */ |
segundo | 0:ac1725ba162c | 541 | tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(), |
segundo | 0:ac1725ba162c | 542 | tcphdr->dest, tcphdr->src); |
segundo | 0:ac1725ba162c | 543 | return ERR_OK; |
segundo | 0:ac1725ba162c | 544 | } |
segundo | 0:ac1725ba162c | 545 | } else if (flags & TCP_FIN) { |
segundo | 0:ac1725ba162c | 546 | /* - eighth, check the FIN bit: Remain in the TIME-WAIT state. |
segundo | 0:ac1725ba162c | 547 | Restart the 2 MSL time-wait timeout.*/ |
segundo | 0:ac1725ba162c | 548 | pcb->tmr = tcp_ticks; |
segundo | 0:ac1725ba162c | 549 | } |
segundo | 0:ac1725ba162c | 550 | |
segundo | 0:ac1725ba162c | 551 | if ((tcplen > 0)) { |
segundo | 0:ac1725ba162c | 552 | /* Acknowledge data, FIN or out-of-window SYN */ |
segundo | 0:ac1725ba162c | 553 | pcb->flags |= TF_ACK_NOW; |
segundo | 0:ac1725ba162c | 554 | return tcp_output(pcb); |
segundo | 0:ac1725ba162c | 555 | } |
segundo | 0:ac1725ba162c | 556 | return ERR_OK; |
segundo | 0:ac1725ba162c | 557 | } |
segundo | 0:ac1725ba162c | 558 | |
segundo | 0:ac1725ba162c | 559 | /** |
segundo | 0:ac1725ba162c | 560 | * Implements the TCP state machine. Called by tcp_input. In some |
segundo | 0:ac1725ba162c | 561 | * states tcp_receive() is called to receive data. The tcp_seg |
segundo | 0:ac1725ba162c | 562 | * argument will be freed by the caller (tcp_input()) unless the |
segundo | 0:ac1725ba162c | 563 | * recv_data pointer in the pcb is set. |
segundo | 0:ac1725ba162c | 564 | * |
segundo | 0:ac1725ba162c | 565 | * @param pcb the tcp_pcb for which a segment arrived |
segundo | 0:ac1725ba162c | 566 | * |
segundo | 0:ac1725ba162c | 567 | * @note the segment which arrived is saved in global variables, therefore only the pcb |
segundo | 0:ac1725ba162c | 568 | * involved is passed as a parameter to this function |
segundo | 0:ac1725ba162c | 569 | */ |
segundo | 0:ac1725ba162c | 570 | static err_t |
segundo | 0:ac1725ba162c | 571 | tcp_process(struct tcp_pcb *pcb) |
segundo | 0:ac1725ba162c | 572 | { |
segundo | 0:ac1725ba162c | 573 | struct tcp_seg *rseg; |
segundo | 0:ac1725ba162c | 574 | u8_t acceptable = 0; |
segundo | 0:ac1725ba162c | 575 | err_t err; |
segundo | 0:ac1725ba162c | 576 | |
segundo | 0:ac1725ba162c | 577 | err = ERR_OK; |
segundo | 0:ac1725ba162c | 578 | |
segundo | 0:ac1725ba162c | 579 | /* Process incoming RST segments. */ |
segundo | 0:ac1725ba162c | 580 | if (flags & TCP_RST) { |
segundo | 0:ac1725ba162c | 581 | /* First, determine if the reset is acceptable. */ |
segundo | 0:ac1725ba162c | 582 | if (pcb->state == SYN_SENT) { |
segundo | 0:ac1725ba162c | 583 | if (ackno == pcb->snd_nxt) { |
segundo | 0:ac1725ba162c | 584 | acceptable = 1; |
segundo | 0:ac1725ba162c | 585 | } |
segundo | 0:ac1725ba162c | 586 | } else { |
segundo | 0:ac1725ba162c | 587 | if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, |
segundo | 0:ac1725ba162c | 588 | pcb->rcv_nxt+pcb->rcv_wnd)) { |
segundo | 0:ac1725ba162c | 589 | acceptable = 1; |
segundo | 0:ac1725ba162c | 590 | } |
segundo | 0:ac1725ba162c | 591 | } |
segundo | 0:ac1725ba162c | 592 | |
segundo | 0:ac1725ba162c | 593 | if (acceptable) { |
segundo | 0:ac1725ba162c | 594 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n")); |
segundo | 0:ac1725ba162c | 595 | LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED); |
segundo | 0:ac1725ba162c | 596 | recv_flags |= TF_RESET; |
segundo | 0:ac1725ba162c | 597 | pcb->flags &= ~TF_ACK_DELAY; |
segundo | 0:ac1725ba162c | 598 | return ERR_RST; |
segundo | 0:ac1725ba162c | 599 | } else { |
segundo | 0:ac1725ba162c | 600 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n", |
segundo | 0:ac1725ba162c | 601 | seqno, pcb->rcv_nxt)); |
segundo | 0:ac1725ba162c | 602 | LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n", |
segundo | 0:ac1725ba162c | 603 | seqno, pcb->rcv_nxt)); |
segundo | 0:ac1725ba162c | 604 | return ERR_OK; |
segundo | 0:ac1725ba162c | 605 | } |
segundo | 0:ac1725ba162c | 606 | } |
segundo | 0:ac1725ba162c | 607 | |
segundo | 0:ac1725ba162c | 608 | if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) { |
segundo | 0:ac1725ba162c | 609 | /* Cope with new connection attempt after remote end crashed */ |
segundo | 0:ac1725ba162c | 610 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 611 | return ERR_OK; |
segundo | 0:ac1725ba162c | 612 | } |
segundo | 0:ac1725ba162c | 613 | |
segundo | 0:ac1725ba162c | 614 | if ((pcb->flags & TF_RXCLOSED) == 0) { |
segundo | 0:ac1725ba162c | 615 | /* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */ |
segundo | 0:ac1725ba162c | 616 | pcb->tmr = tcp_ticks; |
segundo | 0:ac1725ba162c | 617 | } |
segundo | 0:ac1725ba162c | 618 | pcb->keep_cnt_sent = 0; |
segundo | 0:ac1725ba162c | 619 | |
segundo | 0:ac1725ba162c | 620 | tcp_parseopt(pcb); |
segundo | 0:ac1725ba162c | 621 | |
segundo | 0:ac1725ba162c | 622 | /* Do different things depending on the TCP state. */ |
segundo | 0:ac1725ba162c | 623 | switch (pcb->state) { |
segundo | 0:ac1725ba162c | 624 | case SYN_SENT: |
segundo | 0:ac1725ba162c | 625 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno, |
segundo | 0:ac1725ba162c | 626 | pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno))); |
segundo | 0:ac1725ba162c | 627 | /* received SYN ACK with expected sequence number? */ |
segundo | 0:ac1725ba162c | 628 | if ((flags & TCP_ACK) && (flags & TCP_SYN) |
segundo | 0:ac1725ba162c | 629 | && ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) { |
segundo | 0:ac1725ba162c | 630 | pcb->snd_buf++; |
segundo | 0:ac1725ba162c | 631 | pcb->rcv_nxt = seqno + 1; |
segundo | 0:ac1725ba162c | 632 | pcb->rcv_ann_right_edge = pcb->rcv_nxt; |
segundo | 0:ac1725ba162c | 633 | pcb->lastack = ackno; |
segundo | 0:ac1725ba162c | 634 | pcb->snd_wnd = tcphdr->wnd; |
segundo | 0:ac1725ba162c | 635 | pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */ |
segundo | 0:ac1725ba162c | 636 | pcb->state = ESTABLISHED; |
segundo | 0:ac1725ba162c | 637 | |
segundo | 0:ac1725ba162c | 638 | #if TCP_CALCULATE_EFF_SEND_MSS |
segundo | 0:ac1725ba162c | 639 | pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip)); |
segundo | 0:ac1725ba162c | 640 | #endif /* TCP_CALCULATE_EFF_SEND_MSS */ |
segundo | 0:ac1725ba162c | 641 | |
segundo | 0:ac1725ba162c | 642 | /* Set ssthresh again after changing pcb->mss (already set in tcp_connect |
segundo | 0:ac1725ba162c | 643 | * but for the default value of pcb->mss) */ |
segundo | 0:ac1725ba162c | 644 | pcb->ssthresh = pcb->mss * 10; |
segundo | 0:ac1725ba162c | 645 | |
segundo | 0:ac1725ba162c | 646 | pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss); |
segundo | 0:ac1725ba162c | 647 | LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0)); |
segundo | 0:ac1725ba162c | 648 | --pcb->snd_queuelen; |
segundo | 0:ac1725ba162c | 649 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen)); |
segundo | 0:ac1725ba162c | 650 | rseg = pcb->unacked; |
segundo | 0:ac1725ba162c | 651 | pcb->unacked = rseg->next; |
segundo | 0:ac1725ba162c | 652 | |
segundo | 0:ac1725ba162c | 653 | /* If there's nothing left to acknowledge, stop the retransmit |
segundo | 0:ac1725ba162c | 654 | timer, otherwise reset it to start again */ |
segundo | 0:ac1725ba162c | 655 | if(pcb->unacked == NULL) |
segundo | 0:ac1725ba162c | 656 | pcb->rtime = -1; |
segundo | 0:ac1725ba162c | 657 | else { |
segundo | 0:ac1725ba162c | 658 | pcb->rtime = 0; |
segundo | 0:ac1725ba162c | 659 | pcb->nrtx = 0; |
segundo | 0:ac1725ba162c | 660 | } |
segundo | 0:ac1725ba162c | 661 | |
segundo | 0:ac1725ba162c | 662 | tcp_seg_free(rseg); |
segundo | 0:ac1725ba162c | 663 | |
segundo | 0:ac1725ba162c | 664 | /* Call the user specified function to call when sucessfully |
segundo | 0:ac1725ba162c | 665 | * connected. */ |
segundo | 0:ac1725ba162c | 666 | TCP_EVENT_CONNECTED(pcb, ERR_OK, err); |
segundo | 0:ac1725ba162c | 667 | if (err == ERR_ABRT) { |
segundo | 0:ac1725ba162c | 668 | return ERR_ABRT; |
segundo | 0:ac1725ba162c | 669 | } |
segundo | 0:ac1725ba162c | 670 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 671 | } |
segundo | 0:ac1725ba162c | 672 | /* received ACK? possibly a half-open connection */ |
segundo | 0:ac1725ba162c | 673 | else if (flags & TCP_ACK) { |
segundo | 0:ac1725ba162c | 674 | /* send a RST to bring the other side in a non-synchronized state. */ |
segundo | 0:ac1725ba162c | 675 | tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(), |
segundo | 0:ac1725ba162c | 676 | tcphdr->dest, tcphdr->src); |
segundo | 0:ac1725ba162c | 677 | } |
segundo | 0:ac1725ba162c | 678 | break; |
segundo | 0:ac1725ba162c | 679 | case SYN_RCVD: |
segundo | 0:ac1725ba162c | 680 | if (flags & TCP_ACK) { |
segundo | 0:ac1725ba162c | 681 | /* expected ACK number? */ |
segundo | 0:ac1725ba162c | 682 | if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) { |
segundo | 0:ac1725ba162c | 683 | u16_t old_cwnd; |
segundo | 0:ac1725ba162c | 684 | pcb->state = ESTABLISHED; |
segundo | 0:ac1725ba162c | 685 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
segundo | 0:ac1725ba162c | 686 | #if LWIP_CALLBACK_API |
segundo | 0:ac1725ba162c | 687 | LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL); |
segundo | 0:ac1725ba162c | 688 | #endif |
segundo | 0:ac1725ba162c | 689 | /* Call the accept function. */ |
segundo | 0:ac1725ba162c | 690 | TCP_EVENT_ACCEPT(pcb, ERR_OK, err); |
segundo | 0:ac1725ba162c | 691 | if (err != ERR_OK) { |
segundo | 0:ac1725ba162c | 692 | /* If the accept function returns with an error, we abort |
segundo | 0:ac1725ba162c | 693 | * the connection. */ |
segundo | 0:ac1725ba162c | 694 | /* Already aborted? */ |
segundo | 0:ac1725ba162c | 695 | if (err != ERR_ABRT) { |
segundo | 0:ac1725ba162c | 696 | tcp_abort(pcb); |
segundo | 0:ac1725ba162c | 697 | } |
segundo | 0:ac1725ba162c | 698 | return ERR_ABRT; |
segundo | 0:ac1725ba162c | 699 | } |
segundo | 0:ac1725ba162c | 700 | old_cwnd = pcb->cwnd; |
segundo | 0:ac1725ba162c | 701 | /* If there was any data contained within this ACK, |
segundo | 0:ac1725ba162c | 702 | * we'd better pass it on to the application as well. */ |
segundo | 0:ac1725ba162c | 703 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 704 | |
segundo | 0:ac1725ba162c | 705 | /* Prevent ACK for SYN to generate a sent event */ |
segundo | 0:ac1725ba162c | 706 | if (pcb->acked != 0) { |
segundo | 0:ac1725ba162c | 707 | pcb->acked--; |
segundo | 0:ac1725ba162c | 708 | } |
segundo | 0:ac1725ba162c | 709 | |
segundo | 0:ac1725ba162c | 710 | pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss); |
segundo | 0:ac1725ba162c | 711 | |
segundo | 0:ac1725ba162c | 712 | if (recv_flags & TF_GOT_FIN) { |
segundo | 0:ac1725ba162c | 713 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 714 | pcb->state = CLOSE_WAIT; |
segundo | 0:ac1725ba162c | 715 | } |
segundo | 0:ac1725ba162c | 716 | } else { |
segundo | 0:ac1725ba162c | 717 | /* incorrect ACK number, send RST */ |
segundo | 0:ac1725ba162c | 718 | tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(), |
segundo | 0:ac1725ba162c | 719 | tcphdr->dest, tcphdr->src); |
segundo | 0:ac1725ba162c | 720 | } |
segundo | 0:ac1725ba162c | 721 | } else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) { |
segundo | 0:ac1725ba162c | 722 | /* Looks like another copy of the SYN - retransmit our SYN-ACK */ |
segundo | 0:ac1725ba162c | 723 | tcp_rexmit(pcb); |
segundo | 0:ac1725ba162c | 724 | } |
segundo | 0:ac1725ba162c | 725 | break; |
segundo | 0:ac1725ba162c | 726 | case CLOSE_WAIT: |
segundo | 0:ac1725ba162c | 727 | /* FALLTHROUGH */ |
segundo | 0:ac1725ba162c | 728 | case ESTABLISHED: |
segundo | 0:ac1725ba162c | 729 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 730 | if (recv_flags & TF_GOT_FIN) { /* passive close */ |
segundo | 0:ac1725ba162c | 731 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 732 | pcb->state = CLOSE_WAIT; |
segundo | 0:ac1725ba162c | 733 | } |
segundo | 0:ac1725ba162c | 734 | break; |
segundo | 0:ac1725ba162c | 735 | case FIN_WAIT_1: |
segundo | 0:ac1725ba162c | 736 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 737 | if (recv_flags & TF_GOT_FIN) { |
segundo | 0:ac1725ba162c | 738 | if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) { |
segundo | 0:ac1725ba162c | 739 | LWIP_DEBUGF(TCP_DEBUG, |
segundo | 0:ac1725ba162c | 740 | ("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
segundo | 0:ac1725ba162c | 741 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 742 | tcp_pcb_purge(pcb); |
segundo | 0:ac1725ba162c | 743 | TCP_RMV(&tcp_active_pcbs, pcb); |
segundo | 0:ac1725ba162c | 744 | pcb->state = TIME_WAIT; |
segundo | 0:ac1725ba162c | 745 | TCP_REG(&tcp_tw_pcbs, pcb); |
segundo | 0:ac1725ba162c | 746 | } else { |
segundo | 0:ac1725ba162c | 747 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 748 | pcb->state = CLOSING; |
segundo | 0:ac1725ba162c | 749 | } |
segundo | 0:ac1725ba162c | 750 | } else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) { |
segundo | 0:ac1725ba162c | 751 | pcb->state = FIN_WAIT_2; |
segundo | 0:ac1725ba162c | 752 | } |
segundo | 0:ac1725ba162c | 753 | break; |
segundo | 0:ac1725ba162c | 754 | case FIN_WAIT_2: |
segundo | 0:ac1725ba162c | 755 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 756 | if (recv_flags & TF_GOT_FIN) { |
segundo | 0:ac1725ba162c | 757 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
segundo | 0:ac1725ba162c | 758 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 759 | tcp_pcb_purge(pcb); |
segundo | 0:ac1725ba162c | 760 | TCP_RMV(&tcp_active_pcbs, pcb); |
segundo | 0:ac1725ba162c | 761 | pcb->state = TIME_WAIT; |
segundo | 0:ac1725ba162c | 762 | TCP_REG(&tcp_tw_pcbs, pcb); |
segundo | 0:ac1725ba162c | 763 | } |
segundo | 0:ac1725ba162c | 764 | break; |
segundo | 0:ac1725ba162c | 765 | case CLOSING: |
segundo | 0:ac1725ba162c | 766 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 767 | if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
segundo | 0:ac1725ba162c | 768 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
segundo | 0:ac1725ba162c | 769 | tcp_pcb_purge(pcb); |
segundo | 0:ac1725ba162c | 770 | TCP_RMV(&tcp_active_pcbs, pcb); |
segundo | 0:ac1725ba162c | 771 | pcb->state = TIME_WAIT; |
segundo | 0:ac1725ba162c | 772 | TCP_REG(&tcp_tw_pcbs, pcb); |
segundo | 0:ac1725ba162c | 773 | } |
segundo | 0:ac1725ba162c | 774 | break; |
segundo | 0:ac1725ba162c | 775 | case LAST_ACK: |
segundo | 0:ac1725ba162c | 776 | tcp_receive(pcb); |
segundo | 0:ac1725ba162c | 777 | if (flags & TCP_ACK && ackno == pcb->snd_nxt) { |
segundo | 0:ac1725ba162c | 778 | LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest)); |
segundo | 0:ac1725ba162c | 779 | /* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */ |
segundo | 0:ac1725ba162c | 780 | recv_flags |= TF_CLOSED; |
segundo | 0:ac1725ba162c | 781 | } |
segundo | 0:ac1725ba162c | 782 | break; |
segundo | 0:ac1725ba162c | 783 | default: |
segundo | 0:ac1725ba162c | 784 | break; |
segundo | 0:ac1725ba162c | 785 | } |
segundo | 0:ac1725ba162c | 786 | return ERR_OK; |
segundo | 0:ac1725ba162c | 787 | } |
segundo | 0:ac1725ba162c | 788 | |
segundo | 0:ac1725ba162c | 789 | #if TCP_QUEUE_OOSEQ |
segundo | 0:ac1725ba162c | 790 | /** |
segundo | 0:ac1725ba162c | 791 | * Insert segment into the list (segments covered with new one will be deleted) |
segundo | 0:ac1725ba162c | 792 | * |
segundo | 0:ac1725ba162c | 793 | * Called from tcp_receive() |
segundo | 0:ac1725ba162c | 794 | */ |
segundo | 0:ac1725ba162c | 795 | static void |
segundo | 0:ac1725ba162c | 796 | tcp_oos_insert_segment(struct tcp_seg *cseg, struct tcp_seg *next) |
segundo | 0:ac1725ba162c | 797 | { |
segundo | 0:ac1725ba162c | 798 | struct tcp_seg *old_seg; |
segundo | 0:ac1725ba162c | 799 | |
segundo | 0:ac1725ba162c | 800 | if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 801 | /* received segment overlaps all following segments */ |
segundo | 0:ac1725ba162c | 802 | tcp_segs_free(next); |
segundo | 0:ac1725ba162c | 803 | next = NULL; |
segundo | 0:ac1725ba162c | 804 | } |
segundo | 0:ac1725ba162c | 805 | else { |
segundo | 0:ac1725ba162c | 806 | /* delete some following segments |
segundo | 0:ac1725ba162c | 807 | oos queue may have segments with FIN flag */ |
segundo | 0:ac1725ba162c | 808 | while (next && |
segundo | 0:ac1725ba162c | 809 | TCP_SEQ_GEQ((seqno + cseg->len), |
segundo | 0:ac1725ba162c | 810 | (next->tcphdr->seqno + next->len))) { |
segundo | 0:ac1725ba162c | 811 | /* cseg with FIN already processed */ |
segundo | 0:ac1725ba162c | 812 | if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 813 | TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN); |
segundo | 0:ac1725ba162c | 814 | } |
segundo | 0:ac1725ba162c | 815 | old_seg = next; |
segundo | 0:ac1725ba162c | 816 | next = next->next; |
segundo | 0:ac1725ba162c | 817 | tcp_seg_free(old_seg); |
segundo | 0:ac1725ba162c | 818 | } |
segundo | 0:ac1725ba162c | 819 | if (next && |
segundo | 0:ac1725ba162c | 820 | TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) { |
segundo | 0:ac1725ba162c | 821 | /* We need to trim the incoming segment. */ |
segundo | 0:ac1725ba162c | 822 | cseg->len = (u16_t)(next->tcphdr->seqno - seqno); |
segundo | 0:ac1725ba162c | 823 | pbuf_realloc(cseg->p, cseg->len); |
segundo | 0:ac1725ba162c | 824 | } |
segundo | 0:ac1725ba162c | 825 | } |
segundo | 0:ac1725ba162c | 826 | cseg->next = next; |
segundo | 0:ac1725ba162c | 827 | } |
segundo | 0:ac1725ba162c | 828 | #endif /* TCP_QUEUE_OOSEQ */ |
segundo | 0:ac1725ba162c | 829 | |
segundo | 0:ac1725ba162c | 830 | /** |
segundo | 0:ac1725ba162c | 831 | * Called by tcp_process. Checks if the given segment is an ACK for outstanding |
segundo | 0:ac1725ba162c | 832 | * data, and if so frees the memory of the buffered data. Next, is places the |
segundo | 0:ac1725ba162c | 833 | * segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment |
segundo | 0:ac1725ba162c | 834 | * is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until |
segundo | 0:ac1725ba162c | 835 | * i it has been removed from the buffer. |
segundo | 0:ac1725ba162c | 836 | * |
segundo | 0:ac1725ba162c | 837 | * If the incoming segment constitutes an ACK for a segment that was used for RTT |
segundo | 0:ac1725ba162c | 838 | * estimation, the RTT is estimated here as well. |
segundo | 0:ac1725ba162c | 839 | * |
segundo | 0:ac1725ba162c | 840 | * Called from tcp_process(). |
segundo | 0:ac1725ba162c | 841 | */ |
segundo | 0:ac1725ba162c | 842 | static void |
segundo | 0:ac1725ba162c | 843 | tcp_receive(struct tcp_pcb *pcb) |
segundo | 0:ac1725ba162c | 844 | { |
segundo | 0:ac1725ba162c | 845 | struct tcp_seg *next; |
segundo | 0:ac1725ba162c | 846 | #if TCP_QUEUE_OOSEQ |
segundo | 0:ac1725ba162c | 847 | struct tcp_seg *prev, *cseg; |
segundo | 0:ac1725ba162c | 848 | #endif /* TCP_QUEUE_OOSEQ */ |
segundo | 0:ac1725ba162c | 849 | struct pbuf *p; |
segundo | 0:ac1725ba162c | 850 | s32_t off; |
segundo | 0:ac1725ba162c | 851 | s16_t m; |
segundo | 0:ac1725ba162c | 852 | u32_t right_wnd_edge; |
segundo | 0:ac1725ba162c | 853 | u16_t new_tot_len; |
segundo | 0:ac1725ba162c | 854 | int found_dupack = 0; |
segundo | 0:ac1725ba162c | 855 | |
segundo | 0:ac1725ba162c | 856 | if (flags & TCP_ACK) { |
segundo | 0:ac1725ba162c | 857 | right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2; |
segundo | 0:ac1725ba162c | 858 | |
segundo | 0:ac1725ba162c | 859 | /* Update window. */ |
segundo | 0:ac1725ba162c | 860 | if (TCP_SEQ_LT(pcb->snd_wl1, seqno) || |
segundo | 0:ac1725ba162c | 861 | (pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) || |
segundo | 0:ac1725ba162c | 862 | (pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) { |
segundo | 0:ac1725ba162c | 863 | pcb->snd_wnd = tcphdr->wnd; |
segundo | 0:ac1725ba162c | 864 | pcb->snd_wl1 = seqno; |
segundo | 0:ac1725ba162c | 865 | pcb->snd_wl2 = ackno; |
segundo | 0:ac1725ba162c | 866 | if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) { |
segundo | 0:ac1725ba162c | 867 | pcb->persist_backoff = 0; |
segundo | 0:ac1725ba162c | 868 | } |
segundo | 0:ac1725ba162c | 869 | LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd)); |
segundo | 0:ac1725ba162c | 870 | #if TCP_WND_DEBUG |
segundo | 0:ac1725ba162c | 871 | } else { |
segundo | 0:ac1725ba162c | 872 | if (pcb->snd_wnd != tcphdr->wnd) { |
segundo | 0:ac1725ba162c | 873 | LWIP_DEBUGF(TCP_WND_DEBUG, |
segundo | 0:ac1725ba162c | 874 | ("tcp_receive: no window update lastack %"U32_F" ackno %" |
segundo | 0:ac1725ba162c | 875 | U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n", |
segundo | 0:ac1725ba162c | 876 | pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2)); |
segundo | 0:ac1725ba162c | 877 | } |
segundo | 0:ac1725ba162c | 878 | #endif /* TCP_WND_DEBUG */ |
segundo | 0:ac1725ba162c | 879 | } |
segundo | 0:ac1725ba162c | 880 | |
segundo | 0:ac1725ba162c | 881 | /* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a |
segundo | 0:ac1725ba162c | 882 | * duplicate ack if: |
segundo | 0:ac1725ba162c | 883 | * 1) It doesn't ACK new data |
segundo | 0:ac1725ba162c | 884 | * 2) length of received packet is zero (i.e. no payload) |
segundo | 0:ac1725ba162c | 885 | * 3) the advertised window hasn't changed |
segundo | 0:ac1725ba162c | 886 | * 4) There is outstanding unacknowledged data (retransmission timer running) |
segundo | 0:ac1725ba162c | 887 | * 5) The ACK is == biggest ACK sequence number so far seen (snd_una) |
segundo | 0:ac1725ba162c | 888 | * |
segundo | 0:ac1725ba162c | 889 | * If it passes all five, should process as a dupack: |
segundo | 0:ac1725ba162c | 890 | * a) dupacks < 3: do nothing |
segundo | 0:ac1725ba162c | 891 | * b) dupacks == 3: fast retransmit |
segundo | 0:ac1725ba162c | 892 | * c) dupacks > 3: increase cwnd |
segundo | 0:ac1725ba162c | 893 | * |
segundo | 0:ac1725ba162c | 894 | * If it only passes 1-3, should reset dupack counter (and add to |
segundo | 0:ac1725ba162c | 895 | * stats, which we don't do in lwIP) |
segundo | 0:ac1725ba162c | 896 | * |
segundo | 0:ac1725ba162c | 897 | * If it only passes 1, should reset dupack counter |
segundo | 0:ac1725ba162c | 898 | * |
segundo | 0:ac1725ba162c | 899 | */ |
segundo | 0:ac1725ba162c | 900 | |
segundo | 0:ac1725ba162c | 901 | /* Clause 1 */ |
segundo | 0:ac1725ba162c | 902 | if (TCP_SEQ_LEQ(ackno, pcb->lastack)) { |
segundo | 0:ac1725ba162c | 903 | pcb->acked = 0; |
segundo | 0:ac1725ba162c | 904 | /* Clause 2 */ |
segundo | 0:ac1725ba162c | 905 | if (tcplen == 0) { |
segundo | 0:ac1725ba162c | 906 | /* Clause 3 */ |
segundo | 0:ac1725ba162c | 907 | if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){ |
segundo | 0:ac1725ba162c | 908 | /* Clause 4 */ |
segundo | 0:ac1725ba162c | 909 | if (pcb->rtime >= 0) { |
segundo | 0:ac1725ba162c | 910 | /* Clause 5 */ |
segundo | 0:ac1725ba162c | 911 | if (pcb->lastack == ackno) { |
segundo | 0:ac1725ba162c | 912 | found_dupack = 1; |
segundo | 0:ac1725ba162c | 913 | if (pcb->dupacks + 1 > pcb->dupacks) |
segundo | 0:ac1725ba162c | 914 | ++pcb->dupacks; |
segundo | 0:ac1725ba162c | 915 | if (pcb->dupacks > 3) { |
segundo | 0:ac1725ba162c | 916 | /* Inflate the congestion window, but not if it means that |
segundo | 0:ac1725ba162c | 917 | the value overflows. */ |
segundo | 0:ac1725ba162c | 918 | if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { |
segundo | 0:ac1725ba162c | 919 | pcb->cwnd += pcb->mss; |
segundo | 0:ac1725ba162c | 920 | } |
segundo | 0:ac1725ba162c | 921 | } else if (pcb->dupacks == 3) { |
segundo | 0:ac1725ba162c | 922 | /* Do fast retransmit */ |
segundo | 0:ac1725ba162c | 923 | tcp_rexmit_fast(pcb); |
segundo | 0:ac1725ba162c | 924 | } |
segundo | 0:ac1725ba162c | 925 | } |
segundo | 0:ac1725ba162c | 926 | } |
segundo | 0:ac1725ba162c | 927 | } |
segundo | 0:ac1725ba162c | 928 | } |
segundo | 0:ac1725ba162c | 929 | /* If Clause (1) or more is true, but not a duplicate ack, reset |
segundo | 0:ac1725ba162c | 930 | * count of consecutive duplicate acks */ |
segundo | 0:ac1725ba162c | 931 | if (!found_dupack) { |
segundo | 0:ac1725ba162c | 932 | pcb->dupacks = 0; |
segundo | 0:ac1725ba162c | 933 | } |
segundo | 0:ac1725ba162c | 934 | } else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){ |
segundo | 0:ac1725ba162c | 935 | /* We come here when the ACK acknowledges new data. */ |
segundo | 0:ac1725ba162c | 936 | |
segundo | 0:ac1725ba162c | 937 | /* Reset the "IN Fast Retransmit" flag, since we are no longer |
segundo | 0:ac1725ba162c | 938 | in fast retransmit. Also reset the congestion window to the |
segundo | 0:ac1725ba162c | 939 | slow start threshold. */ |
segundo | 0:ac1725ba162c | 940 | if (pcb->flags & TF_INFR) { |
segundo | 0:ac1725ba162c | 941 | pcb->flags &= ~TF_INFR; |
segundo | 0:ac1725ba162c | 942 | pcb->cwnd = pcb->ssthresh; |
segundo | 0:ac1725ba162c | 943 | } |
segundo | 0:ac1725ba162c | 944 | |
segundo | 0:ac1725ba162c | 945 | /* Reset the number of retransmissions. */ |
segundo | 0:ac1725ba162c | 946 | pcb->nrtx = 0; |
segundo | 0:ac1725ba162c | 947 | |
segundo | 0:ac1725ba162c | 948 | /* Reset the retransmission time-out. */ |
segundo | 0:ac1725ba162c | 949 | pcb->rto = (pcb->sa >> 3) + pcb->sv; |
segundo | 0:ac1725ba162c | 950 | |
segundo | 0:ac1725ba162c | 951 | /* Update the send buffer space. Diff between the two can never exceed 64K? */ |
segundo | 0:ac1725ba162c | 952 | pcb->acked = (u16_t)(ackno - pcb->lastack); |
segundo | 0:ac1725ba162c | 953 | |
segundo | 0:ac1725ba162c | 954 | pcb->snd_buf += pcb->acked; |
segundo | 0:ac1725ba162c | 955 | |
segundo | 0:ac1725ba162c | 956 | /* Reset the fast retransmit variables. */ |
segundo | 0:ac1725ba162c | 957 | pcb->dupacks = 0; |
segundo | 0:ac1725ba162c | 958 | pcb->lastack = ackno; |
segundo | 0:ac1725ba162c | 959 | |
segundo | 0:ac1725ba162c | 960 | /* Update the congestion control variables (cwnd and |
segundo | 0:ac1725ba162c | 961 | ssthresh). */ |
segundo | 0:ac1725ba162c | 962 | if (pcb->state >= ESTABLISHED) { |
segundo | 0:ac1725ba162c | 963 | if (pcb->cwnd < pcb->ssthresh) { |
segundo | 0:ac1725ba162c | 964 | if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) { |
segundo | 0:ac1725ba162c | 965 | pcb->cwnd += pcb->mss; |
segundo | 0:ac1725ba162c | 966 | } |
segundo | 0:ac1725ba162c | 967 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd)); |
segundo | 0:ac1725ba162c | 968 | } else { |
segundo | 0:ac1725ba162c | 969 | u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd); |
segundo | 0:ac1725ba162c | 970 | if (new_cwnd > pcb->cwnd) { |
segundo | 0:ac1725ba162c | 971 | pcb->cwnd = new_cwnd; |
segundo | 0:ac1725ba162c | 972 | } |
segundo | 0:ac1725ba162c | 973 | LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd)); |
segundo | 0:ac1725ba162c | 974 | } |
segundo | 0:ac1725ba162c | 975 | } |
segundo | 0:ac1725ba162c | 976 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n", |
segundo | 0:ac1725ba162c | 977 | ackno, |
segundo | 0:ac1725ba162c | 978 | pcb->unacked != NULL? |
segundo | 0:ac1725ba162c | 979 | ntohl(pcb->unacked->tcphdr->seqno): 0, |
segundo | 0:ac1725ba162c | 980 | pcb->unacked != NULL? |
segundo | 0:ac1725ba162c | 981 | ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0)); |
segundo | 0:ac1725ba162c | 982 | |
segundo | 0:ac1725ba162c | 983 | /* Remove segment from the unacknowledged list if the incoming |
segundo | 0:ac1725ba162c | 984 | ACK acknowlegdes them. */ |
segundo | 0:ac1725ba162c | 985 | while (pcb->unacked != NULL && |
segundo | 0:ac1725ba162c | 986 | TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) + |
segundo | 0:ac1725ba162c | 987 | TCP_TCPLEN(pcb->unacked), ackno)) { |
segundo | 0:ac1725ba162c | 988 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n", |
segundo | 0:ac1725ba162c | 989 | ntohl(pcb->unacked->tcphdr->seqno), |
segundo | 0:ac1725ba162c | 990 | ntohl(pcb->unacked->tcphdr->seqno) + |
segundo | 0:ac1725ba162c | 991 | TCP_TCPLEN(pcb->unacked))); |
segundo | 0:ac1725ba162c | 992 | |
segundo | 0:ac1725ba162c | 993 | next = pcb->unacked; |
segundo | 0:ac1725ba162c | 994 | pcb->unacked = pcb->unacked->next; |
segundo | 0:ac1725ba162c | 995 | |
segundo | 0:ac1725ba162c | 996 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen)); |
segundo | 0:ac1725ba162c | 997 | LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p))); |
segundo | 0:ac1725ba162c | 998 | /* Prevent ACK for FIN to generate a sent event */ |
segundo | 0:ac1725ba162c | 999 | if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) { |
segundo | 0:ac1725ba162c | 1000 | pcb->acked--; |
segundo | 0:ac1725ba162c | 1001 | } |
segundo | 0:ac1725ba162c | 1002 | |
segundo | 0:ac1725ba162c | 1003 | pcb->snd_queuelen -= pbuf_clen(next->p); |
segundo | 0:ac1725ba162c | 1004 | tcp_seg_free(next); |
segundo | 0:ac1725ba162c | 1005 | |
segundo | 0:ac1725ba162c | 1006 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen)); |
segundo | 0:ac1725ba162c | 1007 | if (pcb->snd_queuelen != 0) { |
segundo | 0:ac1725ba162c | 1008 | LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL || |
segundo | 0:ac1725ba162c | 1009 | pcb->unsent != NULL); |
segundo | 0:ac1725ba162c | 1010 | } |
segundo | 0:ac1725ba162c | 1011 | } |
segundo | 0:ac1725ba162c | 1012 | |
segundo | 0:ac1725ba162c | 1013 | /* If there's nothing left to acknowledge, stop the retransmit |
segundo | 0:ac1725ba162c | 1014 | timer, otherwise reset it to start again */ |
segundo | 0:ac1725ba162c | 1015 | if(pcb->unacked == NULL) |
segundo | 0:ac1725ba162c | 1016 | pcb->rtime = -1; |
segundo | 0:ac1725ba162c | 1017 | else |
segundo | 0:ac1725ba162c | 1018 | pcb->rtime = 0; |
segundo | 0:ac1725ba162c | 1019 | |
segundo | 0:ac1725ba162c | 1020 | pcb->polltmr = 0; |
segundo | 0:ac1725ba162c | 1021 | } else { |
segundo | 0:ac1725ba162c | 1022 | /* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */ |
segundo | 0:ac1725ba162c | 1023 | pcb->acked = 0; |
segundo | 0:ac1725ba162c | 1024 | } |
segundo | 0:ac1725ba162c | 1025 | |
segundo | 0:ac1725ba162c | 1026 | /* We go through the ->unsent list to see if any of the segments |
segundo | 0:ac1725ba162c | 1027 | on the list are acknowledged by the ACK. This may seem |
segundo | 0:ac1725ba162c | 1028 | strange since an "unsent" segment shouldn't be acked. The |
segundo | 0:ac1725ba162c | 1029 | rationale is that lwIP puts all outstanding segments on the |
segundo | 0:ac1725ba162c | 1030 | ->unsent list after a retransmission, so these segments may |
segundo | 0:ac1725ba162c | 1031 | in fact have been sent once. */ |
segundo | 0:ac1725ba162c | 1032 | while (pcb->unsent != NULL && |
segundo | 0:ac1725ba162c | 1033 | TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) + |
segundo | 0:ac1725ba162c | 1034 | TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) { |
segundo | 0:ac1725ba162c | 1035 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n", |
segundo | 0:ac1725ba162c | 1036 | ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) + |
segundo | 0:ac1725ba162c | 1037 | TCP_TCPLEN(pcb->unsent))); |
segundo | 0:ac1725ba162c | 1038 | |
segundo | 0:ac1725ba162c | 1039 | next = pcb->unsent; |
segundo | 0:ac1725ba162c | 1040 | pcb->unsent = pcb->unsent->next; |
segundo | 0:ac1725ba162c | 1041 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen)); |
segundo | 0:ac1725ba162c | 1042 | LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p))); |
segundo | 0:ac1725ba162c | 1043 | /* Prevent ACK for FIN to generate a sent event */ |
segundo | 0:ac1725ba162c | 1044 | if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) { |
segundo | 0:ac1725ba162c | 1045 | pcb->acked--; |
segundo | 0:ac1725ba162c | 1046 | } |
segundo | 0:ac1725ba162c | 1047 | pcb->snd_queuelen -= pbuf_clen(next->p); |
segundo | 0:ac1725ba162c | 1048 | tcp_seg_free(next); |
segundo | 0:ac1725ba162c | 1049 | LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen)); |
segundo | 0:ac1725ba162c | 1050 | if (pcb->snd_queuelen != 0) { |
segundo | 0:ac1725ba162c | 1051 | LWIP_ASSERT("tcp_receive: valid queue length", |
segundo | 0:ac1725ba162c | 1052 | pcb->unacked != NULL || pcb->unsent != NULL); |
segundo | 0:ac1725ba162c | 1053 | } |
segundo | 0:ac1725ba162c | 1054 | } |
segundo | 0:ac1725ba162c | 1055 | /* End of ACK for new data processing. */ |
segundo | 0:ac1725ba162c | 1056 | |
segundo | 0:ac1725ba162c | 1057 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n", |
segundo | 0:ac1725ba162c | 1058 | pcb->rttest, pcb->rtseq, ackno)); |
segundo | 0:ac1725ba162c | 1059 | |
segundo | 0:ac1725ba162c | 1060 | /* RTT estimation calculations. This is done by checking if the |
segundo | 0:ac1725ba162c | 1061 | incoming segment acknowledges the segment we use to take a |
segundo | 0:ac1725ba162c | 1062 | round-trip time measurement. */ |
segundo | 0:ac1725ba162c | 1063 | if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) { |
segundo | 0:ac1725ba162c | 1064 | /* diff between this shouldn't exceed 32K since this are tcp timer ticks |
segundo | 0:ac1725ba162c | 1065 | and a round-trip shouldn't be that long... */ |
segundo | 0:ac1725ba162c | 1066 | m = (s16_t)(tcp_ticks - pcb->rttest); |
segundo | 0:ac1725ba162c | 1067 | |
segundo | 0:ac1725ba162c | 1068 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n", |
segundo | 0:ac1725ba162c | 1069 | m, m * TCP_SLOW_INTERVAL)); |
segundo | 0:ac1725ba162c | 1070 | |
segundo | 0:ac1725ba162c | 1071 | /* This is taken directly from VJs original code in his paper */ |
segundo | 0:ac1725ba162c | 1072 | m = m - (pcb->sa >> 3); |
segundo | 0:ac1725ba162c | 1073 | pcb->sa += m; |
segundo | 0:ac1725ba162c | 1074 | if (m < 0) { |
segundo | 0:ac1725ba162c | 1075 | m = -m; |
segundo | 0:ac1725ba162c | 1076 | } |
segundo | 0:ac1725ba162c | 1077 | m = m - (pcb->sv >> 2); |
segundo | 0:ac1725ba162c | 1078 | pcb->sv += m; |
segundo | 0:ac1725ba162c | 1079 | pcb->rto = (pcb->sa >> 3) + pcb->sv; |
segundo | 0:ac1725ba162c | 1080 | |
segundo | 0:ac1725ba162c | 1081 | LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n", |
segundo | 0:ac1725ba162c | 1082 | pcb->rto, pcb->rto * TCP_SLOW_INTERVAL)); |
segundo | 0:ac1725ba162c | 1083 | |
segundo | 0:ac1725ba162c | 1084 | pcb->rttest = 0; |
segundo | 0:ac1725ba162c | 1085 | } |
segundo | 0:ac1725ba162c | 1086 | } |
segundo | 0:ac1725ba162c | 1087 | |
segundo | 0:ac1725ba162c | 1088 | /* If the incoming segment contains data, we must process it |
segundo | 0:ac1725ba162c | 1089 | further. */ |
segundo | 0:ac1725ba162c | 1090 | if (tcplen > 0) { |
segundo | 0:ac1725ba162c | 1091 | /* This code basically does three things: |
segundo | 0:ac1725ba162c | 1092 | |
segundo | 0:ac1725ba162c | 1093 | +) If the incoming segment contains data that is the next |
segundo | 0:ac1725ba162c | 1094 | in-sequence data, this data is passed to the application. This |
segundo | 0:ac1725ba162c | 1095 | might involve trimming the first edge of the data. The rcv_nxt |
segundo | 0:ac1725ba162c | 1096 | variable and the advertised window are adjusted. |
segundo | 0:ac1725ba162c | 1097 | |
segundo | 0:ac1725ba162c | 1098 | +) If the incoming segment has data that is above the next |
segundo | 0:ac1725ba162c | 1099 | sequence number expected (->rcv_nxt), the segment is placed on |
segundo | 0:ac1725ba162c | 1100 | the ->ooseq queue. This is done by finding the appropriate |
segundo | 0:ac1725ba162c | 1101 | place in the ->ooseq queue (which is ordered by sequence |
segundo | 0:ac1725ba162c | 1102 | number) and trim the segment in both ends if needed. An |
segundo | 0:ac1725ba162c | 1103 | immediate ACK is sent to indicate that we received an |
segundo | 0:ac1725ba162c | 1104 | out-of-sequence segment. |
segundo | 0:ac1725ba162c | 1105 | |
segundo | 0:ac1725ba162c | 1106 | +) Finally, we check if the first segment on the ->ooseq queue |
segundo | 0:ac1725ba162c | 1107 | now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If |
segundo | 0:ac1725ba162c | 1108 | rcv_nxt > ooseq->seqno, we must trim the first edge of the |
segundo | 0:ac1725ba162c | 1109 | segment on ->ooseq before we adjust rcv_nxt. The data in the |
segundo | 0:ac1725ba162c | 1110 | segments that are now on sequence are chained onto the |
segundo | 0:ac1725ba162c | 1111 | incoming segment so that we only need to call the application |
segundo | 0:ac1725ba162c | 1112 | once. |
segundo | 0:ac1725ba162c | 1113 | */ |
segundo | 0:ac1725ba162c | 1114 | |
segundo | 0:ac1725ba162c | 1115 | /* First, we check if we must trim the first edge. We have to do |
segundo | 0:ac1725ba162c | 1116 | this if the sequence number of the incoming segment is less |
segundo | 0:ac1725ba162c | 1117 | than rcv_nxt, and the sequence number plus the length of the |
segundo | 0:ac1725ba162c | 1118 | segment is larger than rcv_nxt. */ |
segundo | 0:ac1725ba162c | 1119 | /* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){ |
segundo | 0:ac1725ba162c | 1120 | if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/ |
segundo | 0:ac1725ba162c | 1121 | if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){ |
segundo | 0:ac1725ba162c | 1122 | /* Trimming the first edge is done by pushing the payload |
segundo | 0:ac1725ba162c | 1123 | pointer in the pbuf downwards. This is somewhat tricky since |
segundo | 0:ac1725ba162c | 1124 | we do not want to discard the full contents of the pbuf up to |
segundo | 0:ac1725ba162c | 1125 | the new starting point of the data since we have to keep the |
segundo | 0:ac1725ba162c | 1126 | TCP header which is present in the first pbuf in the chain. |
segundo | 0:ac1725ba162c | 1127 | |
segundo | 0:ac1725ba162c | 1128 | What is done is really quite a nasty hack: the first pbuf in |
segundo | 0:ac1725ba162c | 1129 | the pbuf chain is pointed to by inseg.p. Since we need to be |
segundo | 0:ac1725ba162c | 1130 | able to deallocate the whole pbuf, we cannot change this |
segundo | 0:ac1725ba162c | 1131 | inseg.p pointer to point to any of the later pbufs in the |
segundo | 0:ac1725ba162c | 1132 | chain. Instead, we point the ->payload pointer in the first |
segundo | 0:ac1725ba162c | 1133 | pbuf to data in one of the later pbufs. We also set the |
segundo | 0:ac1725ba162c | 1134 | inseg.data pointer to point to the right place. This way, the |
segundo | 0:ac1725ba162c | 1135 | ->p pointer will still point to the first pbuf, but the |
segundo | 0:ac1725ba162c | 1136 | ->p->payload pointer will point to data in another pbuf. |
segundo | 0:ac1725ba162c | 1137 | |
segundo | 0:ac1725ba162c | 1138 | After we are done with adjusting the pbuf pointers we must |
segundo | 0:ac1725ba162c | 1139 | adjust the ->data pointer in the seg and the segment |
segundo | 0:ac1725ba162c | 1140 | length.*/ |
segundo | 0:ac1725ba162c | 1141 | |
segundo | 0:ac1725ba162c | 1142 | off = pcb->rcv_nxt - seqno; |
segundo | 0:ac1725ba162c | 1143 | p = inseg.p; |
segundo | 0:ac1725ba162c | 1144 | LWIP_ASSERT("inseg.p != NULL", inseg.p); |
segundo | 0:ac1725ba162c | 1145 | LWIP_ASSERT("insane offset!", (off < 0x7fff)); |
segundo | 0:ac1725ba162c | 1146 | if (inseg.p->len < off) { |
segundo | 0:ac1725ba162c | 1147 | LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off)); |
segundo | 0:ac1725ba162c | 1148 | new_tot_len = (u16_t)(inseg.p->tot_len - off); |
segundo | 0:ac1725ba162c | 1149 | while (p->len < off) { |
segundo | 0:ac1725ba162c | 1150 | off -= p->len; |
segundo | 0:ac1725ba162c | 1151 | /* KJM following line changed (with addition of new_tot_len var) |
segundo | 0:ac1725ba162c | 1152 | to fix bug #9076 |
segundo | 0:ac1725ba162c | 1153 | inseg.p->tot_len -= p->len; */ |
segundo | 0:ac1725ba162c | 1154 | p->tot_len = new_tot_len; |
segundo | 0:ac1725ba162c | 1155 | p->len = 0; |
segundo | 0:ac1725ba162c | 1156 | p = p->next; |
segundo | 0:ac1725ba162c | 1157 | } |
segundo | 0:ac1725ba162c | 1158 | if(pbuf_header(p, (s16_t)-off)) { |
segundo | 0:ac1725ba162c | 1159 | /* Do we need to cope with this failing? Assert for now */ |
segundo | 0:ac1725ba162c | 1160 | LWIP_ASSERT("pbuf_header failed", 0); |
segundo | 0:ac1725ba162c | 1161 | } |
segundo | 0:ac1725ba162c | 1162 | } else { |
segundo | 0:ac1725ba162c | 1163 | if(pbuf_header(inseg.p, (s16_t)-off)) { |
segundo | 0:ac1725ba162c | 1164 | /* Do we need to cope with this failing? Assert for now */ |
segundo | 0:ac1725ba162c | 1165 | LWIP_ASSERT("pbuf_header failed", 0); |
segundo | 0:ac1725ba162c | 1166 | } |
segundo | 0:ac1725ba162c | 1167 | } |
segundo | 0:ac1725ba162c | 1168 | /* KJM following line changed to use p->payload rather than inseg->p->payload |
segundo | 0:ac1725ba162c | 1169 | to fix bug #9076 */ |
segundo | 0:ac1725ba162c | 1170 | inseg.dataptr = p->payload; |
segundo | 0:ac1725ba162c | 1171 | inseg.len -= (u16_t)(pcb->rcv_nxt - seqno); |
segundo | 0:ac1725ba162c | 1172 | inseg.tcphdr->seqno = seqno = pcb->rcv_nxt; |
segundo | 0:ac1725ba162c | 1173 | } |
segundo | 0:ac1725ba162c | 1174 | else { |
segundo | 0:ac1725ba162c | 1175 | if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){ |
segundo | 0:ac1725ba162c | 1176 | /* the whole segment is < rcv_nxt */ |
segundo | 0:ac1725ba162c | 1177 | /* must be a duplicate of a packet that has already been correctly handled */ |
segundo | 0:ac1725ba162c | 1178 | |
segundo | 0:ac1725ba162c | 1179 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno)); |
segundo | 0:ac1725ba162c | 1180 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 1181 | } |
segundo | 0:ac1725ba162c | 1182 | } |
segundo | 0:ac1725ba162c | 1183 | |
segundo | 0:ac1725ba162c | 1184 | /* The sequence number must be within the window (above rcv_nxt |
segundo | 0:ac1725ba162c | 1185 | and below rcv_nxt + rcv_wnd) in order to be further |
segundo | 0:ac1725ba162c | 1186 | processed. */ |
segundo | 0:ac1725ba162c | 1187 | if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, |
segundo | 0:ac1725ba162c | 1188 | pcb->rcv_nxt + pcb->rcv_wnd - 1)){ |
segundo | 0:ac1725ba162c | 1189 | if (pcb->rcv_nxt == seqno) { |
segundo | 0:ac1725ba162c | 1190 | /* The incoming segment is the next in sequence. We check if |
segundo | 0:ac1725ba162c | 1191 | we have to trim the end of the segment and update rcv_nxt |
segundo | 0:ac1725ba162c | 1192 | and pass the data to the application. */ |
segundo | 0:ac1725ba162c | 1193 | tcplen = TCP_TCPLEN(&inseg); |
segundo | 0:ac1725ba162c | 1194 | |
segundo | 0:ac1725ba162c | 1195 | if (tcplen > pcb->rcv_wnd) { |
segundo | 0:ac1725ba162c | 1196 | LWIP_DEBUGF(TCP_INPUT_DEBUG, |
segundo | 0:ac1725ba162c | 1197 | ("tcp_receive: other end overran receive window" |
segundo | 0:ac1725ba162c | 1198 | "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n", |
segundo | 0:ac1725ba162c | 1199 | seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd)); |
segundo | 0:ac1725ba162c | 1200 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1201 | /* Must remove the FIN from the header as we're trimming |
segundo | 0:ac1725ba162c | 1202 | * that byte of sequence-space from the packet */ |
segundo | 0:ac1725ba162c | 1203 | TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN); |
segundo | 0:ac1725ba162c | 1204 | } |
segundo | 0:ac1725ba162c | 1205 | /* Adjust length of segment to fit in the window. */ |
segundo | 0:ac1725ba162c | 1206 | inseg.len = pcb->rcv_wnd; |
segundo | 0:ac1725ba162c | 1207 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) { |
segundo | 0:ac1725ba162c | 1208 | inseg.len -= 1; |
segundo | 0:ac1725ba162c | 1209 | } |
segundo | 0:ac1725ba162c | 1210 | pbuf_realloc(inseg.p, inseg.len); |
segundo | 0:ac1725ba162c | 1211 | tcplen = TCP_TCPLEN(&inseg); |
segundo | 0:ac1725ba162c | 1212 | LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n", |
segundo | 0:ac1725ba162c | 1213 | (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd)); |
segundo | 0:ac1725ba162c | 1214 | } |
segundo | 0:ac1725ba162c | 1215 | #if TCP_QUEUE_OOSEQ |
segundo | 0:ac1725ba162c | 1216 | /* Received in-sequence data, adjust ooseq data if: |
segundo | 0:ac1725ba162c | 1217 | - FIN has been received or |
segundo | 0:ac1725ba162c | 1218 | - inseq overlaps with ooseq */ |
segundo | 0:ac1725ba162c | 1219 | if (pcb->ooseq != NULL) { |
segundo | 0:ac1725ba162c | 1220 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1221 | LWIP_DEBUGF(TCP_INPUT_DEBUG, |
segundo | 0:ac1725ba162c | 1222 | ("tcp_receive: received in-order FIN, binning ooseq queue\n")); |
segundo | 0:ac1725ba162c | 1223 | /* Received in-order FIN means anything that was received |
segundo | 0:ac1725ba162c | 1224 | * out of order must now have been received in-order, so |
segundo | 0:ac1725ba162c | 1225 | * bin the ooseq queue */ |
segundo | 0:ac1725ba162c | 1226 | while (pcb->ooseq != NULL) { |
segundo | 0:ac1725ba162c | 1227 | struct tcp_seg *old_ooseq = pcb->ooseq; |
segundo | 0:ac1725ba162c | 1228 | pcb->ooseq = pcb->ooseq->next; |
segundo | 0:ac1725ba162c | 1229 | tcp_seg_free(old_ooseq); |
segundo | 0:ac1725ba162c | 1230 | } |
segundo | 0:ac1725ba162c | 1231 | } |
segundo | 0:ac1725ba162c | 1232 | else { |
segundo | 0:ac1725ba162c | 1233 | next = pcb->ooseq; |
segundo | 0:ac1725ba162c | 1234 | /* Remove all segments on ooseq that are covered by inseg already. |
segundo | 0:ac1725ba162c | 1235 | * FIN is copied from ooseq to inseg if present. */ |
segundo | 0:ac1725ba162c | 1236 | while (next && |
segundo | 0:ac1725ba162c | 1237 | TCP_SEQ_GEQ(seqno + tcplen, |
segundo | 0:ac1725ba162c | 1238 | next->tcphdr->seqno + next->len)) { |
segundo | 0:ac1725ba162c | 1239 | /* inseg cannot have FIN here (already processed above) */ |
segundo | 0:ac1725ba162c | 1240 | if (TCPH_FLAGS(next->tcphdr) & TCP_FIN && |
segundo | 0:ac1725ba162c | 1241 | (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) { |
segundo | 0:ac1725ba162c | 1242 | TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN); |
segundo | 0:ac1725ba162c | 1243 | tcplen = TCP_TCPLEN(&inseg); |
segundo | 0:ac1725ba162c | 1244 | } |
segundo | 0:ac1725ba162c | 1245 | prev = next; |
segundo | 0:ac1725ba162c | 1246 | next = next->next; |
segundo | 0:ac1725ba162c | 1247 | tcp_seg_free(prev); |
segundo | 0:ac1725ba162c | 1248 | } |
segundo | 0:ac1725ba162c | 1249 | /* Now trim right side of inseg if it overlaps with the first |
segundo | 0:ac1725ba162c | 1250 | * segment on ooseq */ |
segundo | 0:ac1725ba162c | 1251 | if (next && |
segundo | 0:ac1725ba162c | 1252 | TCP_SEQ_GT(seqno + tcplen, |
segundo | 0:ac1725ba162c | 1253 | next->tcphdr->seqno)) { |
segundo | 0:ac1725ba162c | 1254 | /* inseg cannot have FIN here (already processed above) */ |
segundo | 0:ac1725ba162c | 1255 | inseg.len = (u16_t)(next->tcphdr->seqno - seqno); |
segundo | 0:ac1725ba162c | 1256 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) { |
segundo | 0:ac1725ba162c | 1257 | inseg.len -= 1; |
segundo | 0:ac1725ba162c | 1258 | } |
segundo | 0:ac1725ba162c | 1259 | pbuf_realloc(inseg.p, inseg.len); |
segundo | 0:ac1725ba162c | 1260 | tcplen = TCP_TCPLEN(&inseg); |
segundo | 0:ac1725ba162c | 1261 | LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n", |
segundo | 0:ac1725ba162c | 1262 | (seqno + tcplen) == next->tcphdr->seqno); |
segundo | 0:ac1725ba162c | 1263 | } |
segundo | 0:ac1725ba162c | 1264 | pcb->ooseq = next; |
segundo | 0:ac1725ba162c | 1265 | } |
segundo | 0:ac1725ba162c | 1266 | } |
segundo | 0:ac1725ba162c | 1267 | #endif /* TCP_QUEUE_OOSEQ */ |
segundo | 0:ac1725ba162c | 1268 | |
segundo | 0:ac1725ba162c | 1269 | pcb->rcv_nxt = seqno + tcplen; |
segundo | 0:ac1725ba162c | 1270 | |
segundo | 0:ac1725ba162c | 1271 | /* Update the receiver's (our) window. */ |
segundo | 0:ac1725ba162c | 1272 | LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen); |
segundo | 0:ac1725ba162c | 1273 | pcb->rcv_wnd -= tcplen; |
segundo | 0:ac1725ba162c | 1274 | |
segundo | 0:ac1725ba162c | 1275 | tcp_update_rcv_ann_wnd(pcb); |
segundo | 0:ac1725ba162c | 1276 | |
segundo | 0:ac1725ba162c | 1277 | /* If there is data in the segment, we make preparations to |
segundo | 0:ac1725ba162c | 1278 | pass this up to the application. The ->recv_data variable |
segundo | 0:ac1725ba162c | 1279 | is used for holding the pbuf that goes to the |
segundo | 0:ac1725ba162c | 1280 | application. The code for reassembling out-of-sequence data |
segundo | 0:ac1725ba162c | 1281 | chains its data on this pbuf as well. |
segundo | 0:ac1725ba162c | 1282 | |
segundo | 0:ac1725ba162c | 1283 | If the segment was a FIN, we set the TF_GOT_FIN flag that will |
segundo | 0:ac1725ba162c | 1284 | be used to indicate to the application that the remote side has |
segundo | 0:ac1725ba162c | 1285 | closed its end of the connection. */ |
segundo | 0:ac1725ba162c | 1286 | if (inseg.p->tot_len > 0) { |
segundo | 0:ac1725ba162c | 1287 | recv_data = inseg.p; |
segundo | 0:ac1725ba162c | 1288 | /* Since this pbuf now is the responsibility of the |
segundo | 0:ac1725ba162c | 1289 | application, we delete our reference to it so that we won't |
segundo | 0:ac1725ba162c | 1290 | (mistakingly) deallocate it. */ |
segundo | 0:ac1725ba162c | 1291 | inseg.p = NULL; |
segundo | 0:ac1725ba162c | 1292 | } |
segundo | 0:ac1725ba162c | 1293 | if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1294 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n")); |
segundo | 0:ac1725ba162c | 1295 | recv_flags |= TF_GOT_FIN; |
segundo | 0:ac1725ba162c | 1296 | } |
segundo | 0:ac1725ba162c | 1297 | |
segundo | 0:ac1725ba162c | 1298 | #if TCP_QUEUE_OOSEQ |
segundo | 0:ac1725ba162c | 1299 | /* We now check if we have segments on the ->ooseq queue that |
segundo | 0:ac1725ba162c | 1300 | are now in sequence. */ |
segundo | 0:ac1725ba162c | 1301 | while (pcb->ooseq != NULL && |
segundo | 0:ac1725ba162c | 1302 | pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) { |
segundo | 0:ac1725ba162c | 1303 | |
segundo | 0:ac1725ba162c | 1304 | cseg = pcb->ooseq; |
segundo | 0:ac1725ba162c | 1305 | seqno = pcb->ooseq->tcphdr->seqno; |
segundo | 0:ac1725ba162c | 1306 | |
segundo | 0:ac1725ba162c | 1307 | pcb->rcv_nxt += TCP_TCPLEN(cseg); |
segundo | 0:ac1725ba162c | 1308 | LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n", |
segundo | 0:ac1725ba162c | 1309 | pcb->rcv_wnd >= TCP_TCPLEN(cseg)); |
segundo | 0:ac1725ba162c | 1310 | pcb->rcv_wnd -= TCP_TCPLEN(cseg); |
segundo | 0:ac1725ba162c | 1311 | |
segundo | 0:ac1725ba162c | 1312 | tcp_update_rcv_ann_wnd(pcb); |
segundo | 0:ac1725ba162c | 1313 | |
segundo | 0:ac1725ba162c | 1314 | if (cseg->p->tot_len > 0) { |
segundo | 0:ac1725ba162c | 1315 | /* Chain this pbuf onto the pbuf that we will pass to |
segundo | 0:ac1725ba162c | 1316 | the application. */ |
segundo | 0:ac1725ba162c | 1317 | if (recv_data) { |
segundo | 0:ac1725ba162c | 1318 | pbuf_cat(recv_data, cseg->p); |
segundo | 0:ac1725ba162c | 1319 | } else { |
segundo | 0:ac1725ba162c | 1320 | recv_data = cseg->p; |
segundo | 0:ac1725ba162c | 1321 | } |
segundo | 0:ac1725ba162c | 1322 | cseg->p = NULL; |
segundo | 0:ac1725ba162c | 1323 | } |
segundo | 0:ac1725ba162c | 1324 | if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1325 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n")); |
segundo | 0:ac1725ba162c | 1326 | recv_flags |= TF_GOT_FIN; |
segundo | 0:ac1725ba162c | 1327 | if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */ |
segundo | 0:ac1725ba162c | 1328 | pcb->state = CLOSE_WAIT; |
segundo | 0:ac1725ba162c | 1329 | } |
segundo | 0:ac1725ba162c | 1330 | } |
segundo | 0:ac1725ba162c | 1331 | |
segundo | 0:ac1725ba162c | 1332 | pcb->ooseq = cseg->next; |
segundo | 0:ac1725ba162c | 1333 | tcp_seg_free(cseg); |
segundo | 0:ac1725ba162c | 1334 | } |
segundo | 0:ac1725ba162c | 1335 | #endif /* TCP_QUEUE_OOSEQ */ |
segundo | 0:ac1725ba162c | 1336 | |
segundo | 0:ac1725ba162c | 1337 | |
segundo | 0:ac1725ba162c | 1338 | /* Acknowledge the segment(s). */ |
segundo | 0:ac1725ba162c | 1339 | tcp_ack(pcb); |
segundo | 0:ac1725ba162c | 1340 | |
segundo | 0:ac1725ba162c | 1341 | } else { |
segundo | 0:ac1725ba162c | 1342 | /* We get here if the incoming segment is out-of-sequence. */ |
segundo | 0:ac1725ba162c | 1343 | tcp_send_empty_ack(pcb); |
segundo | 0:ac1725ba162c | 1344 | #if TCP_QUEUE_OOSEQ |
segundo | 0:ac1725ba162c | 1345 | /* We queue the segment on the ->ooseq queue. */ |
segundo | 0:ac1725ba162c | 1346 | if (pcb->ooseq == NULL) { |
segundo | 0:ac1725ba162c | 1347 | pcb->ooseq = tcp_seg_copy(&inseg); |
segundo | 0:ac1725ba162c | 1348 | } else { |
segundo | 0:ac1725ba162c | 1349 | /* If the queue is not empty, we walk through the queue and |
segundo | 0:ac1725ba162c | 1350 | try to find a place where the sequence number of the |
segundo | 0:ac1725ba162c | 1351 | incoming segment is between the sequence numbers of the |
segundo | 0:ac1725ba162c | 1352 | previous and the next segment on the ->ooseq queue. That is |
segundo | 0:ac1725ba162c | 1353 | the place where we put the incoming segment. If needed, we |
segundo | 0:ac1725ba162c | 1354 | trim the second edges of the previous and the incoming |
segundo | 0:ac1725ba162c | 1355 | segment so that it will fit into the sequence. |
segundo | 0:ac1725ba162c | 1356 | |
segundo | 0:ac1725ba162c | 1357 | If the incoming segment has the same sequence number as a |
segundo | 0:ac1725ba162c | 1358 | segment on the ->ooseq queue, we discard the segment that |
segundo | 0:ac1725ba162c | 1359 | contains less data. */ |
segundo | 0:ac1725ba162c | 1360 | |
segundo | 0:ac1725ba162c | 1361 | prev = NULL; |
segundo | 0:ac1725ba162c | 1362 | for(next = pcb->ooseq; next != NULL; next = next->next) { |
segundo | 0:ac1725ba162c | 1363 | if (seqno == next->tcphdr->seqno) { |
segundo | 0:ac1725ba162c | 1364 | /* The sequence number of the incoming segment is the |
segundo | 0:ac1725ba162c | 1365 | same as the sequence number of the segment on |
segundo | 0:ac1725ba162c | 1366 | ->ooseq. We check the lengths to see which one to |
segundo | 0:ac1725ba162c | 1367 | discard. */ |
segundo | 0:ac1725ba162c | 1368 | if (inseg.len > next->len) { |
segundo | 0:ac1725ba162c | 1369 | /* The incoming segment is larger than the old |
segundo | 0:ac1725ba162c | 1370 | segment. We replace some segments with the new |
segundo | 0:ac1725ba162c | 1371 | one. */ |
segundo | 0:ac1725ba162c | 1372 | cseg = tcp_seg_copy(&inseg); |
segundo | 0:ac1725ba162c | 1373 | if (cseg != NULL) { |
segundo | 0:ac1725ba162c | 1374 | if (prev != NULL) { |
segundo | 0:ac1725ba162c | 1375 | prev->next = cseg; |
segundo | 0:ac1725ba162c | 1376 | } else { |
segundo | 0:ac1725ba162c | 1377 | pcb->ooseq = cseg; |
segundo | 0:ac1725ba162c | 1378 | } |
segundo | 0:ac1725ba162c | 1379 | tcp_oos_insert_segment(cseg, next); |
segundo | 0:ac1725ba162c | 1380 | } |
segundo | 0:ac1725ba162c | 1381 | break; |
segundo | 0:ac1725ba162c | 1382 | } else { |
segundo | 0:ac1725ba162c | 1383 | /* Either the lenghts are the same or the incoming |
segundo | 0:ac1725ba162c | 1384 | segment was smaller than the old one; in either |
segundo | 0:ac1725ba162c | 1385 | case, we ditch the incoming segment. */ |
segundo | 0:ac1725ba162c | 1386 | break; |
segundo | 0:ac1725ba162c | 1387 | } |
segundo | 0:ac1725ba162c | 1388 | } else { |
segundo | 0:ac1725ba162c | 1389 | if (prev == NULL) { |
segundo | 0:ac1725ba162c | 1390 | if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) { |
segundo | 0:ac1725ba162c | 1391 | /* The sequence number of the incoming segment is lower |
segundo | 0:ac1725ba162c | 1392 | than the sequence number of the first segment on the |
segundo | 0:ac1725ba162c | 1393 | queue. We put the incoming segment first on the |
segundo | 0:ac1725ba162c | 1394 | queue. */ |
segundo | 0:ac1725ba162c | 1395 | cseg = tcp_seg_copy(&inseg); |
segundo | 0:ac1725ba162c | 1396 | if (cseg != NULL) { |
segundo | 0:ac1725ba162c | 1397 | pcb->ooseq = cseg; |
segundo | 0:ac1725ba162c | 1398 | tcp_oos_insert_segment(cseg, next); |
segundo | 0:ac1725ba162c | 1399 | } |
segundo | 0:ac1725ba162c | 1400 | break; |
segundo | 0:ac1725ba162c | 1401 | } |
segundo | 0:ac1725ba162c | 1402 | } else { |
segundo | 0:ac1725ba162c | 1403 | /*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) && |
segundo | 0:ac1725ba162c | 1404 | TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/ |
segundo | 0:ac1725ba162c | 1405 | if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) { |
segundo | 0:ac1725ba162c | 1406 | /* The sequence number of the incoming segment is in |
segundo | 0:ac1725ba162c | 1407 | between the sequence numbers of the previous and |
segundo | 0:ac1725ba162c | 1408 | the next segment on ->ooseq. We trim trim the previous |
segundo | 0:ac1725ba162c | 1409 | segment, delete next segments that included in received segment |
segundo | 0:ac1725ba162c | 1410 | and trim received, if needed. */ |
segundo | 0:ac1725ba162c | 1411 | cseg = tcp_seg_copy(&inseg); |
segundo | 0:ac1725ba162c | 1412 | if (cseg != NULL) { |
segundo | 0:ac1725ba162c | 1413 | if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) { |
segundo | 0:ac1725ba162c | 1414 | /* We need to trim the prev segment. */ |
segundo | 0:ac1725ba162c | 1415 | prev->len = (u16_t)(seqno - prev->tcphdr->seqno); |
segundo | 0:ac1725ba162c | 1416 | pbuf_realloc(prev->p, prev->len); |
segundo | 0:ac1725ba162c | 1417 | } |
segundo | 0:ac1725ba162c | 1418 | prev->next = cseg; |
segundo | 0:ac1725ba162c | 1419 | tcp_oos_insert_segment(cseg, next); |
segundo | 0:ac1725ba162c | 1420 | } |
segundo | 0:ac1725ba162c | 1421 | break; |
segundo | 0:ac1725ba162c | 1422 | } |
segundo | 0:ac1725ba162c | 1423 | } |
segundo | 0:ac1725ba162c | 1424 | /* If the "next" segment is the last segment on the |
segundo | 0:ac1725ba162c | 1425 | ooseq queue, we add the incoming segment to the end |
segundo | 0:ac1725ba162c | 1426 | of the list. */ |
segundo | 0:ac1725ba162c | 1427 | if (next->next == NULL && |
segundo | 0:ac1725ba162c | 1428 | TCP_SEQ_GT(seqno, next->tcphdr->seqno)) { |
segundo | 0:ac1725ba162c | 1429 | if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1430 | /* segment "next" already contains all data */ |
segundo | 0:ac1725ba162c | 1431 | break; |
segundo | 0:ac1725ba162c | 1432 | } |
segundo | 0:ac1725ba162c | 1433 | next->next = tcp_seg_copy(&inseg); |
segundo | 0:ac1725ba162c | 1434 | if (next->next != NULL) { |
segundo | 0:ac1725ba162c | 1435 | if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) { |
segundo | 0:ac1725ba162c | 1436 | /* We need to trim the last segment. */ |
segundo | 0:ac1725ba162c | 1437 | next->len = (u16_t)(seqno - next->tcphdr->seqno); |
segundo | 0:ac1725ba162c | 1438 | pbuf_realloc(next->p, next->len); |
segundo | 0:ac1725ba162c | 1439 | } |
segundo | 0:ac1725ba162c | 1440 | /* check if the remote side overruns our receive window */ |
segundo | 0:ac1725ba162c | 1441 | if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) { |
segundo | 0:ac1725ba162c | 1442 | LWIP_DEBUGF(TCP_INPUT_DEBUG, |
segundo | 0:ac1725ba162c | 1443 | ("tcp_receive: other end overran receive window" |
segundo | 0:ac1725ba162c | 1444 | "seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n", |
segundo | 0:ac1725ba162c | 1445 | seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd)); |
segundo | 0:ac1725ba162c | 1446 | if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) { |
segundo | 0:ac1725ba162c | 1447 | /* Must remove the FIN from the header as we're trimming |
segundo | 0:ac1725ba162c | 1448 | * that byte of sequence-space from the packet */ |
segundo | 0:ac1725ba162c | 1449 | TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN); |
segundo | 0:ac1725ba162c | 1450 | } |
segundo | 0:ac1725ba162c | 1451 | /* Adjust length of segment to fit in the window. */ |
segundo | 0:ac1725ba162c | 1452 | next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno; |
segundo | 0:ac1725ba162c | 1453 | pbuf_realloc(next->next->p, next->next->len); |
segundo | 0:ac1725ba162c | 1454 | tcplen = TCP_TCPLEN(next->next); |
segundo | 0:ac1725ba162c | 1455 | LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n", |
segundo | 0:ac1725ba162c | 1456 | (seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd)); |
segundo | 0:ac1725ba162c | 1457 | } |
segundo | 0:ac1725ba162c | 1458 | } |
segundo | 0:ac1725ba162c | 1459 | break; |
segundo | 0:ac1725ba162c | 1460 | } |
segundo | 0:ac1725ba162c | 1461 | } |
segundo | 0:ac1725ba162c | 1462 | prev = next; |
segundo | 0:ac1725ba162c | 1463 | } |
segundo | 0:ac1725ba162c | 1464 | } |
segundo | 0:ac1725ba162c | 1465 | #endif /* TCP_QUEUE_OOSEQ */ |
segundo | 0:ac1725ba162c | 1466 | |
segundo | 0:ac1725ba162c | 1467 | } |
segundo | 0:ac1725ba162c | 1468 | } else { |
segundo | 0:ac1725ba162c | 1469 | /* The incoming segment is not withing the window. */ |
segundo | 0:ac1725ba162c | 1470 | tcp_send_empty_ack(pcb); |
segundo | 0:ac1725ba162c | 1471 | } |
segundo | 0:ac1725ba162c | 1472 | } else { |
segundo | 0:ac1725ba162c | 1473 | /* Segments with length 0 is taken care of here. Segments that |
segundo | 0:ac1725ba162c | 1474 | fall out of the window are ACKed. */ |
segundo | 0:ac1725ba162c | 1475 | /*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) || |
segundo | 0:ac1725ba162c | 1476 | TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/ |
segundo | 0:ac1725ba162c | 1477 | if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){ |
segundo | 0:ac1725ba162c | 1478 | tcp_ack_now(pcb); |
segundo | 0:ac1725ba162c | 1479 | } |
segundo | 0:ac1725ba162c | 1480 | } |
segundo | 0:ac1725ba162c | 1481 | } |
segundo | 0:ac1725ba162c | 1482 | |
segundo | 0:ac1725ba162c | 1483 | /** |
segundo | 0:ac1725ba162c | 1484 | * Parses the options contained in the incoming segment. |
segundo | 0:ac1725ba162c | 1485 | * |
segundo | 0:ac1725ba162c | 1486 | * Called from tcp_listen_input() and tcp_process(). |
segundo | 0:ac1725ba162c | 1487 | * Currently, only the MSS option is supported! |
segundo | 0:ac1725ba162c | 1488 | * |
segundo | 0:ac1725ba162c | 1489 | * @param pcb the tcp_pcb for which a segment arrived |
segundo | 0:ac1725ba162c | 1490 | */ |
segundo | 0:ac1725ba162c | 1491 | static void |
segundo | 0:ac1725ba162c | 1492 | tcp_parseopt(struct tcp_pcb *pcb) |
segundo | 0:ac1725ba162c | 1493 | { |
segundo | 0:ac1725ba162c | 1494 | u16_t c, max_c; |
segundo | 0:ac1725ba162c | 1495 | u16_t mss; |
segundo | 0:ac1725ba162c | 1496 | u8_t *opts, opt; |
segundo | 0:ac1725ba162c | 1497 | #if LWIP_TCP_TIMESTAMPS |
segundo | 0:ac1725ba162c | 1498 | u32_t tsval; |
segundo | 0:ac1725ba162c | 1499 | #endif |
segundo | 0:ac1725ba162c | 1500 | |
segundo | 0:ac1725ba162c | 1501 | opts = (u8_t *)tcphdr + TCP_HLEN; |
segundo | 0:ac1725ba162c | 1502 | |
segundo | 0:ac1725ba162c | 1503 | /* Parse the TCP MSS option, if present. */ |
segundo | 0:ac1725ba162c | 1504 | if(TCPH_HDRLEN(tcphdr) > 0x5) { |
segundo | 0:ac1725ba162c | 1505 | max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2; |
segundo | 0:ac1725ba162c | 1506 | for (c = 0; c < max_c; ) { |
segundo | 0:ac1725ba162c | 1507 | opt = opts[c]; |
segundo | 0:ac1725ba162c | 1508 | switch (opt) { |
segundo | 0:ac1725ba162c | 1509 | case 0x00: |
segundo | 0:ac1725ba162c | 1510 | /* End of options. */ |
segundo | 0:ac1725ba162c | 1511 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n")); |
segundo | 0:ac1725ba162c | 1512 | return; |
segundo | 0:ac1725ba162c | 1513 | case 0x01: |
segundo | 0:ac1725ba162c | 1514 | /* NOP option. */ |
segundo | 0:ac1725ba162c | 1515 | ++c; |
segundo | 0:ac1725ba162c | 1516 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n")); |
segundo | 0:ac1725ba162c | 1517 | break; |
segundo | 0:ac1725ba162c | 1518 | case 0x02: |
segundo | 0:ac1725ba162c | 1519 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n")); |
segundo | 0:ac1725ba162c | 1520 | if (opts[c + 1] != 0x04 || c + 0x04 > max_c) { |
segundo | 0:ac1725ba162c | 1521 | /* Bad length */ |
segundo | 0:ac1725ba162c | 1522 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
segundo | 0:ac1725ba162c | 1523 | return; |
segundo | 0:ac1725ba162c | 1524 | } |
segundo | 0:ac1725ba162c | 1525 | /* An MSS option with the right option length. */ |
segundo | 0:ac1725ba162c | 1526 | mss = (opts[c + 2] << 8) | opts[c + 3]; |
segundo | 0:ac1725ba162c | 1527 | /* Limit the mss to the configured TCP_MSS and prevent division by zero */ |
segundo | 0:ac1725ba162c | 1528 | pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss; |
segundo | 0:ac1725ba162c | 1529 | /* Advance to next option */ |
segundo | 0:ac1725ba162c | 1530 | c += 0x04; |
segundo | 0:ac1725ba162c | 1531 | break; |
segundo | 0:ac1725ba162c | 1532 | #if LWIP_TCP_TIMESTAMPS |
segundo | 0:ac1725ba162c | 1533 | case 0x08: |
segundo | 0:ac1725ba162c | 1534 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n")); |
segundo | 0:ac1725ba162c | 1535 | if (opts[c + 1] != 0x0A || c + 0x0A > max_c) { |
segundo | 0:ac1725ba162c | 1536 | /* Bad length */ |
segundo | 0:ac1725ba162c | 1537 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
segundo | 0:ac1725ba162c | 1538 | return; |
segundo | 0:ac1725ba162c | 1539 | } |
segundo | 0:ac1725ba162c | 1540 | /* TCP timestamp option with valid length */ |
segundo | 0:ac1725ba162c | 1541 | tsval = (opts[c+2]) | (opts[c+3] << 8) | |
segundo | 0:ac1725ba162c | 1542 | (opts[c+4] << 16) | (opts[c+5] << 24); |
segundo | 0:ac1725ba162c | 1543 | if (flags & TCP_SYN) { |
segundo | 0:ac1725ba162c | 1544 | pcb->ts_recent = ntohl(tsval); |
segundo | 0:ac1725ba162c | 1545 | pcb->flags |= TF_TIMESTAMP; |
segundo | 0:ac1725ba162c | 1546 | } else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) { |
segundo | 0:ac1725ba162c | 1547 | pcb->ts_recent = ntohl(tsval); |
segundo | 0:ac1725ba162c | 1548 | } |
segundo | 0:ac1725ba162c | 1549 | /* Advance to next option */ |
segundo | 0:ac1725ba162c | 1550 | c += 0x0A; |
segundo | 0:ac1725ba162c | 1551 | break; |
segundo | 0:ac1725ba162c | 1552 | #endif |
segundo | 0:ac1725ba162c | 1553 | default: |
segundo | 0:ac1725ba162c | 1554 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n")); |
segundo | 0:ac1725ba162c | 1555 | if (opts[c + 1] == 0) { |
segundo | 0:ac1725ba162c | 1556 | LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n")); |
segundo | 0:ac1725ba162c | 1557 | /* If the length field is zero, the options are malformed |
segundo | 0:ac1725ba162c | 1558 | and we don't process them further. */ |
segundo | 0:ac1725ba162c | 1559 | return; |
segundo | 0:ac1725ba162c | 1560 | } |
segundo | 0:ac1725ba162c | 1561 | /* All other options have a length field, so that we easily |
segundo | 0:ac1725ba162c | 1562 | can skip past them. */ |
segundo | 0:ac1725ba162c | 1563 | c += opts[c + 1]; |
segundo | 0:ac1725ba162c | 1564 | } |
segundo | 0:ac1725ba162c | 1565 | } |
segundo | 0:ac1725ba162c | 1566 | } |
segundo | 0:ac1725ba162c | 1567 | } |
segundo | 0:ac1725ba162c | 1568 | |
segundo | 0:ac1725ba162c | 1569 | #endif /* LWIP_TCP */ |