1619 lines
61 KiB
C
1619 lines
61 KiB
C
/**
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* @file
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* Transmission Control Protocol, incoming traffic
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*
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* The input processing functions of the TCP layer.
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*
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* These functions are generally called in the order (ip_input() ->)
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* tcp_input() -> * tcp_process() -> tcp_receive() (-> application).
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*
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*/
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/*
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* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* This file is part of the lwIP TCP/IP stack.
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*
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* Author: Adam Dunkels <adam@sics.se>
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*
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*/
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#include "lwip/opt.h"
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#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
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#include "lwip/tcp_impl.h"
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#include "lwip/def.h"
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#include "lwip/ip_addr.h"
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#include "lwip/netif.h"
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#include "lwip/mem.h"
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#include "lwip/memp.h"
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#include "lwip/inet_chksum.h"
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#include "lwip/stats.h"
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#include "lwip/snmp.h"
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#include "arch/perf.h"
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/* These variables are global to all functions involved in the input
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processing of TCP segments. They are set by the tcp_input()
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function. */
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static struct tcp_seg inseg; //tcp_seg<65>ṹ<EFBFBD><E1B9B9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1>Ķ<EFBFBD>
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static struct tcp_hdr *tcphdr; //<2F><><EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD>TCP<43>ײ<EFBFBD>
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static struct ip_hdr *iphdr; //IP<49><50><EFBFBD>ݰ<EFBFBD><DDB0>ײ<EFBFBD>
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static u32_t seqno, ackno; //TCP<43>ײ<EFBFBD><D7B2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֶ<EFBFBD><D6B6><EFBFBD>ȷ<EFBFBD>Ϻ<EFBFBD><CFBA>ֶ<EFBFBD>
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static u8_t flags; //<2F>ײ<EFBFBD><D7B2><EFBFBD>־<EFBFBD>ֶ<EFBFBD>
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static u16_t tcplen; //TCP<43><50><EFBFBD>ij<EFBFBD><C4B3><EFBFBD>
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static u8_t recv_flags; //<2F><>ǰ<EFBFBD><C7B0><EFBFBD>Ĵ<EFBFBD><C4B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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static struct pbuf *recv_data; //<2F><><EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD><EFBFBD>pbuf
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struct tcp_pcb *tcp_input_pcb; //<2F><>ǰ<EFBFBD><C7B0><EFBFBD>Ŀ<EFBFBD><C4BF>ƿ<EFBFBD>
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/* Forward declarations. */
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static err_t tcp_process(struct tcp_pcb *pcb)ICACHE_FLASH_ATTR;
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static void tcp_receive(struct tcp_pcb *pcb)ICACHE_FLASH_ATTR;
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static void tcp_parseopt(struct tcp_pcb *pcb)ICACHE_FLASH_ATTR;
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static err_t tcp_listen_input(struct tcp_pcb_listen *pcb)ICACHE_FLASH_ATTR;
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static err_t tcp_timewait_input(struct tcp_pcb *pcb)ICACHE_FLASH_ATTR;
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/**
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* The initial input processing of TCP. It verifies the TCP header, demultiplexes
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* the segment between the PCBs and passes it on to tcp_process(), which implements
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* the TCP finite state machine. This function is called by the IP layer (in
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* ip_input()).
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*
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* @param p received TCP segment to process (p->payload pointing to the IP header)
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* @param inp network interface on which this segment was received
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*/
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/**
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* TCP<43><50>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD>봦<EFBFBD><EBB4A6><EFBFBD><EFBFBD><EFBFBD><EFBFBD>֤<EFBFBD><D6A4>TCPͷ<50><CDB7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>IP<49><50><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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* @<40><><EFBFBD><EFBFBD>p:<3A><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>յ<EFBFBD>TCP<43><50>(ָ<><D6B8>IPͷ<50>ĸ<EFBFBD><C4B8><EFBFBD>)
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* @<40><><EFBFBD><EFBFBD>inp:<3A><><EFBFBD>նε<D5B6><CEB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӿ<EFBFBD>
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*/
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void
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tcp_input(struct pbuf *p, struct netif *inp)
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{
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struct tcp_pcb *pcb, *prev;
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struct tcp_pcb_listen *lpcb;
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#if SO_REUSE
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struct tcp_pcb *lpcb_prev = NULL;
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struct tcp_pcb_listen *lpcb_any = NULL;
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#endif /* SO_REUSE */
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u8_t hdrlen;
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err_t err;
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PERF_START;
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TCP_STATS_INC(tcp.recv); //״̬<D7B4><CCAC>1
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snmp_inc_tcpinsegs(); //tcp<63><70><EFBFBD><EFBFBD><EFBFBD>μ<EFBFBD>1
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iphdr = (struct ip_hdr *)p->payload;// pointer to the actual data in the buffer
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/*
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*<2A><>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD>(IHL)<29><>4λ<34><CEBB>IPЭ<50><D0AD><EFBFBD><EFBFBD>ͷ<EFBFBD>ij<EFBFBD><C4B3>ȣ<EFBFBD>ָ<EFBFBD><D6B8>IPv4Э<34><D0AD><EFBFBD><EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD>ȵ<EFBFBD><C8B5>ֽ<EFBFBD><D6BD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ٸ<EFBFBD>32λ<32><CEBB>
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*<2A><><EFBFBD><EFBFBD>IPv4<76>İ<EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD>ܰ<EFBFBD><DCB0><EFBFBD><EFBFBD>ɱ<EFBFBD><C9B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ<EFBFBD>ѡ <20><EFBFBD><EEA3AC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֶο<D6B6><CEBF><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȷ<EFBFBD><C8B7>IPv4<76><34><EFBFBD>ݱ<EFBFBD><DDB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݲ<EFBFBD><DDB2>ֵ<EFBFBD>ƫ<EFBFBD><C6AB><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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*IPv4<76><34>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD>С<EFBFBD><D0A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>20<32><30><EFBFBD>ֽڣ<D6BD><DAA3><EFBFBD><EFBFBD><EFBFBD>IHL<48><4C><EFBFBD><EFBFBD><EFBFBD>ֶε<D6B6><CEB5><EFBFBD>Сֵ<D0A1><D6B5>ʮ<EFBFBD><CAAE><EFBFBD>Ʊ<EFBFBD>ʾ<EFBFBD><CABE><EFBFBD><EFBFBD>5 (5x4 = 20<32>ֽ<EFBFBD>)<29><>
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*<2A><><EFBFBD><EFBFBD>˵<EFBFBD><CBB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʾ<EFBFBD>İ<EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD><EFBFBD>ֽ<EFBFBD><D6BD><EFBFBD><EFBFBD><EFBFBD>4<EFBFBD>ֽڵı<DAB5><C4B1><EFBFBD>
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*/
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tcphdr = (struct tcp_hdr *)((u8_t *)p->payload + IPH_HL(iphdr) * 4);
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#if TCP_INPUT_DEBUG
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tcp_debug_print(tcphdr);
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#endif
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/* remove header from payload */
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if (pbuf_header(p, -((s16_t)(IPH_HL(iphdr) * 4))) || (p->tot_len < sizeof(struct tcp_hdr))) {
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/* drop short packets */
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LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet (%"U16_F" bytes) discarded\n", p->tot_len));
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TCP_STATS_INC(tcp.lenerr);//<2F><><EFBFBD>ȼ<F3B3A4B6><C8BC><EFBFBD>
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TCP_STATS_INC(tcp.drop);//<2F><>ֹ<EFBFBD><D6B9><EFBFBD><EFBFBD>
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snmp_inc_tcpinerrs();
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pbuf_free(p);//<2F>ͷ<EFBFBD>buffer
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return;
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}
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/* Don't even process incoming broadcasts/multicasts. */
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if (ip_addr_isbroadcast(¤t_iphdr_dest, inp) ||
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ip_addr_ismulticast(¤t_iphdr_dest)) {
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TCP_STATS_INC(tcp.proterr);//Э<><D0AD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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TCP_STATS_INC(tcp.drop);
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snmp_inc_tcpinerrs();
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pbuf_free(p);
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return;
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}
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#if CHECKSUM_CHECK_TCP
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/* Verify TCP checksum. */
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if (inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
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IP_PROTO_TCP, p->tot_len) != 0) {
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LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packet discarded due to failing checksum 0x%04"X16_F"\n",
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inet_chksum_pseudo(p, ip_current_src_addr(), ip_current_dest_addr(),
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IP_PROTO_TCP, p->tot_len)));
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#if TCP_DEBUG
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tcp_debug_print(tcphdr);
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#endif /* TCP_DEBUG */
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TCP_STATS_INC(tcp.chkerr);//У<><D0A3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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TCP_STATS_INC(tcp.drop);
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snmp_inc_tcpinerrs();
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pbuf_free(p);
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return;
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}
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#endif
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/* Move the payload pointer in the pbuf so that it points to the
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TCP data instead of the TCP header. */
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hdrlen = TCPH_HDRLEN(tcphdr);//<2F><><EFBFBD><EFBFBD>ͷ<EFBFBD>ij<EFBFBD><C4B3><EFBFBD>
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if(pbuf_header(p, -(hdrlen * 4))){//<2F><><EFBFBD><EFBFBD>TCPͷ<50><CDB7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>0Ϊ<30>ɹ<EFBFBD><C9B9><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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/* drop short packets */
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LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: short packet\n"));
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TCP_STATS_INC(tcp.lenerr);//tcp<63><70><EFBFBD>ȴ<EFBFBD><C8B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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TCP_STATS_INC(tcp.drop);
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snmp_inc_tcpinerrs();
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pbuf_free(p);
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return;
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}
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/* Convert fields in TCP header to host byte order. */
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tcphdr->src = ntohs(tcphdr->src); //ת<><D7AA>Դ<EFBFBD><D4B4>ַ
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tcphdr->dest = ntohs(tcphdr->dest); //ת<><D7AA>Ŀ<EFBFBD>ĵ<EFBFBD>ַ
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seqno = tcphdr->seqno = ntohl(tcphdr->seqno); //ת<><D7AA><EFBFBD><EFBFBD><EFBFBD>к<EFBFBD>
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ackno = tcphdr->ackno = ntohl(tcphdr->ackno); //ת<><D7AA>Ӧ<EFBFBD><D3A6><EFBFBD><EFBFBD>
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tcphdr->wnd = ntohs(tcphdr->wnd); //ת<><D7AA>tcp<63><70><EFBFBD><EFBFBD>
|
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flags = TCPH_FLAGS(tcphdr);//<2F>õ<EFBFBD>tcp header<65>ı<EFBFBD>־
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/*
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*<2A><>־<EFBFBD><D6BE>3λ<33><CEBB><EFBFBD><EFBFBD><EFBFBD>ֶΣ<D6B6><CEA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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* <20><><EFBFBD><EFBFBD>λ<EFBFBD><CEBB>1λ
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* <20><><EFBFBD>ֶ<EFBFBD>λ<EFBFBD><CEBB>1λ<31><CEBB>ȡֵ<C8A1><D6B5>0<EFBFBD><30><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1>ֶΣ<D6B6><CEA3><EFBFBD>1<EFBFBD><31><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1><EFBFBD><EFBFBD>ֶܷΣ<D6B6>
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* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>λ<EFBFBD><CEBB>1λ<31><CEBB>ȡֵ<C8A1><D6B5>0<EFBFBD><30><EFBFBD><EFBFBD><EFBFBD>ݰ<EFBFBD><DDB0><EFBFBD><EFBFBD><EFBFBD>û<EFBFBD>а<EFBFBD><D0B0><EFBFBD><EFBFBD><EFBFBD>1<EFBFBD><31><EFBFBD><EFBFBD><EFBFBD>ݰ<EFBFBD><DDB0><EFBFBD><EFBFBD><EFBFBD><EFBFBD>и<EFBFBD><D0B8><EFBFBD><EFBFBD>İ<EFBFBD><C4B0><EFBFBD>
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*/
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tcplen = p->tot_len + ((flags & (TCP_FIN | TCP_SYN)) ? 1 : 0);//TCP_FIN <20><> TCP_SYN <20><>λ<EFBFBD><CEBB>1<EFBFBD><31><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>0
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/* Demultiplex an incoming segment. First, we check if it is destined
|
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for an active connection. <20><><EFBFBD>ȣ<EFBFBD><C8A3><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD>һ<EFBFBD><D2BB>Ҫ<EFBFBD><D2AA><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD>*/
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////////////////////////////////////////////////////////////////////////////////////////
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prev = NULL;
|
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for(pcb = tcp_active_pcbs; pcb != NULL; pcb = pcb->next) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>б<EFBFBD>
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LWIP_ASSERT("tcp_input: active pcb->state != CLOSED", pcb->state != CLOSED);
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LWIP_ASSERT("tcp_input: active pcb->state != TIME-WAIT", pcb->state != TIME_WAIT);
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LWIP_ASSERT("tcp_input: active pcb->state != LISTEN", pcb->state != LISTEN);
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if (pcb->remote_port == tcphdr->src &&
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pcb->local_port == tcphdr->dest &&
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ip_addr_cmp(&(pcb->remote_ip), ¤t_iphdr_src) &&
|
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ip_addr_cmp(&(pcb->local_ip), ¤t_iphdr_dest)) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>صĵ<D8B5>ַ
|
||
|
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/* Move this PCB to the front of the list so that subsequent
|
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lookups will be faster (we exploit locality in TCP segment
|
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arrivals). */
|
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LWIP_ASSERT("tcp_input: pcb->next != pcb (before cache)", pcb->next != pcb);
|
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if (prev != NULL) {//<2F><><EFBFBD><EFBFBD>ǰһ<C7B0><D2BB><EFBFBD>ڵ㲻Ϊ<E3B2BB><CEAA>
|
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prev->next = pcb->next;
|
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pcb->next = tcp_active_pcbs;
|
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tcp_active_pcbs = pcb;//pcb<63><62><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0>
|
||
}
|
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LWIP_ASSERT("tcp_input: pcb->next != pcb (after cache)", pcb->next != pcb);
|
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break;
|
||
}
|
||
prev = pcb;//prevָ<76><D6B8>pcb
|
||
}
|
||
|
||
if (pcb == NULL) {
|
||
/* If it did not go to an active connection, we check the connections
|
||
in the TIME-WAIT state. */
|
||
for(pcb = tcp_tw_pcbs; pcb != NULL; pcb = pcb->next) {//<2F><><EFBFBD><EFBFBD><EFBFBD>ȴ<EFBFBD>״̬<D7B4>µ<EFBFBD>pcb
|
||
LWIP_ASSERT("tcp_input: TIME-WAIT pcb->state == TIME-WAIT", pcb->state == TIME_WAIT);
|
||
if (pcb->remote_port == tcphdr->src &&
|
||
pcb->local_port == tcphdr->dest &&
|
||
ip_addr_cmp(&(pcb->remote_ip), ¤t_iphdr_src) &&
|
||
ip_addr_cmp(&(pcb->local_ip), ¤t_iphdr_dest)) {
|
||
/* We don't really care enough to move this PCB to the front
|
||
of the list since we are not very likely to receive that
|
||
many segments for connections in TIME-WAIT. */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for TIME_WAITing connection.\n"));
|
||
tcp_timewait_input(pcb);//<2F><><EFBFBD><EFBFBD>tcp timewait <20>İ<EFBFBD>
|
||
pbuf_free(p);
|
||
return;
|
||
}
|
||
}
|
||
|
||
/* Finally, if we still did not get a match, we check all PCBs that
|
||
are LISTENing for incoming connections. */
|
||
prev = NULL;
|
||
for(lpcb = tcp_listen_pcbs.listen_pcbs; lpcb != NULL; lpcb = lpcb->next) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>״̬<D7B4><CCAC><EFBFBD><EFBFBD><EFBFBD>е<EFBFBD>pcb
|
||
if (lpcb->local_port == tcphdr->dest) {
|
||
#if SO_REUSE
|
||
if (ip_addr_cmp(&(lpcb->local_ip), ¤t_iphdr_dest)) {
|
||
/* found an exact match */
|
||
break;
|
||
} else if(ip_addr_isany(&(lpcb->local_ip))) {
|
||
/* found an ANY-match */
|
||
lpcb_any = lpcb;
|
||
lpcb_prev = prev;
|
||
}
|
||
#else /* SO_REUSE */
|
||
if (ip_addr_cmp(&(lpcb->local_ip), ¤t_iphdr_dest) ||
|
||
ip_addr_isany(&(lpcb->local_ip))) {
|
||
/* found a match */
|
||
break;
|
||
}
|
||
#endif /* SO_REUSE */
|
||
}
|
||
prev = (struct tcp_pcb *)lpcb;
|
||
}
|
||
#if SO_REUSE
|
||
/* first try specific local IP */
|
||
if (lpcb == NULL) {
|
||
/* only pass to ANY if no specific local IP has been found */
|
||
lpcb = lpcb_any;
|
||
prev = lpcb_prev;
|
||
}
|
||
#endif /* SO_REUSE */
|
||
if (lpcb != NULL) {
|
||
/* Move this PCB to the front of the list so that subsequent
|
||
lookups will be faster (we exploit locality in TCP segment
|
||
arrivals). */
|
||
if (prev != NULL) {
|
||
((struct tcp_pcb_listen *)prev)->next = lpcb->next;
|
||
/* our successor is the remainder of the listening list */
|
||
lpcb->next = tcp_listen_pcbs.listen_pcbs;
|
||
/* put this listening pcb at the head of the listening list */
|
||
tcp_listen_pcbs.listen_pcbs = lpcb;
|
||
}
|
||
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: packed for LISTENing connection.\n"));
|
||
tcp_listen_input(lpcb);//<2F><><EFBFBD><EFBFBD>tcp<63><70><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݰ<EFBFBD>
|
||
pbuf_free(p);
|
||
return;
|
||
}
|
||
}
|
||
|
||
#if TCP_INPUT_DEBUG
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("+-+-+-+-+-+-+-+-+-+-+-+-+-+- tcp_input: flags "));
|
||
tcp_debug_print_flags(TCPH_FLAGS(tcphdr));
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("-+-+-+-+-+-+-+-+-+-+-+-+-+-+\n"));
|
||
#endif /* TCP_INPUT_DEBUG */
|
||
|
||
|
||
if (pcb != NULL) {
|
||
/* The incoming segment belongs to a connection. */
|
||
#if TCP_INPUT_DEBUG
|
||
#if TCP_DEBUG
|
||
tcp_debug_print_state(pcb->state);
|
||
#endif /* TCP_DEBUG */
|
||
#endif /* TCP_INPUT_DEBUG */
|
||
|
||
/* Set up a tcp_seg structure. */
|
||
inseg.next = NULL;
|
||
inseg.len = p->tot_len;
|
||
inseg.p = p;
|
||
inseg.tcphdr = tcphdr;
|
||
|
||
recv_data = NULL;
|
||
recv_flags = 0;
|
||
|
||
/* If there is data which was previously "refused" by upper layer */
|
||
if (pcb->refused_data != NULL) {
|
||
/* Notify again application with data previously received. */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: notify kept packet\n"));
|
||
TCP_EVENT_RECV(pcb, pcb->refused_data, ERR_OK, err);//pcb<63><62><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
if (err == ERR_OK) {
|
||
pcb->refused_data = NULL;
|
||
} else if ((err == ERR_ABRT) || (tcplen > 0)) {
|
||
/* if err == ERR_ABRT, 'pcb' is already deallocated */
|
||
/* Drop incoming packets because pcb is "full" (only if the incoming
|
||
segment contains data). */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: drop incoming packets, because pcb is \"full\"\n"));
|
||
TCP_STATS_INC(tcp.drop);//tcp<63><70><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
snmp_inc_tcpinerrs();
|
||
pbuf_free(p);
|
||
return;
|
||
}
|
||
}
|
||
tcp_input_pcb = pcb;//<2F><>¼<EFBFBD><C2BC>ǰ<EFBFBD><C7B0><EFBFBD>Ĵ<EFBFBD><C4B4><EFBFBD><EFBFBD>Ŀ<EFBFBD><C4BF>ƿ<EFBFBD>
|
||
err = tcp_process(pcb);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
/* A return value of ERR_ABRT means that tcp_abort() was called
|
||
and that the pcb has been freed. If so, we don't do anything. */
|
||
if (err != ERR_ABRT) {
|
||
if (recv_flags & TF_RESET) {
|
||
/* TF_RESET means that the connection was reset by the other
|
||
end. We then call the error callback to inform the
|
||
application that the connection is dead before we
|
||
deallocate the PCB. */
|
||
TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_RST);
|
||
tcp_pcb_remove(&tcp_active_pcbs, pcb);//ɾ<><C9BE><EFBFBD><EFBFBD><EFBFBD><EFBFBD>pcb<63>б<EFBFBD><D0B1>е<EFBFBD>pcb
|
||
memp_free(MEMP_TCP_PCB, pcb);
|
||
} else if (recv_flags & TF_CLOSED) {
|
||
/* The connection has been closed and we will deallocate the
|
||
PCB. */
|
||
if (!(pcb->flags & TF_RXCLOSED)) {
|
||
/* Connection closed although the application has only shut down the
|
||
tx side: call the PCB's err callback and indicate the closure to
|
||
ensure the application doesn't continue using the PCB. */
|
||
TCP_EVENT_ERR(pcb->errf, pcb->callback_arg, ERR_CLSD);
|
||
}
|
||
tcp_pcb_remove(&tcp_active_pcbs, pcb);
|
||
memp_free(MEMP_TCP_PCB, pcb);
|
||
} else {
|
||
err = ERR_OK;
|
||
/* If the application has registered a "sent" function to be
|
||
called when new send buffer space is available, we call it
|
||
now. */
|
||
if (pcb->acked > 0) {
|
||
TCP_EVENT_SENT(pcb, pcb->acked, err);//<2F><><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD>ȷ<EFBFBD>ϣ<EFBFBD><CFA3>ص<EFBFBD><D8B5>û<EFBFBD><C3BB><EFBFBD>send<6E><64><EFBFBD><EFBFBD>
|
||
if (err == ERR_ABRT) {
|
||
goto aborted;
|
||
}
|
||
}
|
||
|
||
if (recv_data != NULL) {//<2F><><EFBFBD><EFBFBD><EFBFBD>ݽ<EFBFBD><DDBD>յ<EFBFBD>
|
||
LWIP_ASSERT("pcb->refused_data == NULL", pcb->refused_data == NULL);
|
||
if (pcb->flags & TF_RXCLOSED) {
|
||
/* received data although already closed -> abort (send RST) to
|
||
notify the remote host that not all data has been processed */
|
||
pbuf_free(recv_data);
|
||
tcp_abort(pcb);
|
||
goto aborted;
|
||
}
|
||
|
||
//PSH<53><48>־ PSH <20><><EFBFBD><EFBFBD>λ<EFBFBD><CEBB>
|
||
//<2F><>PSH=1ʱ<31><CAB1>Ҫ<EFBFBD><D2AA><EFBFBD><EFBFBD><EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD>Ϸ<EFBFBD><CFB7>÷ֶΣ<D6B6>
|
||
//<2F><><EFBFBD><EFBFBD><EFBFBD>շ<EFBFBD><D5B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ľ<EFBFBD><C4BD><EFBFBD><EFBFBD>Ľ<EFBFBD><C4BD><EFBFBD>Ӧ<EFBFBD>ò㣬<C3B2><E3A3AC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>д<EFBFBD><D0B4><EFBFBD><EFBFBD><EFBFBD>
|
||
|
||
if (flags & TCP_PSH) {
|
||
recv_data->flags |= PBUF_FLAG_PUSH;//<2F><><EFBFBD><EFBFBD>bufferӦ<72><D3A6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
}
|
||
|
||
/* Notify application that data has been received. */
|
||
TCP_EVENT_RECV(pcb, recv_data, ERR_OK, err);
|
||
if (err == ERR_ABRT) {
|
||
goto aborted;
|
||
}
|
||
|
||
/* If the upper layer can't receive this data, store it */
|
||
if (err != ERR_OK) {
|
||
pcb->refused_data = recv_data;
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_input: keep incoming packet, because pcb is \"full\"\n"));
|
||
}
|
||
}
|
||
|
||
/* If a FIN segment was received, we call the callback
|
||
function with a NULL buffer to indicate EOF. */
|
||
if (recv_flags & TF_GOT_FIN) {
|
||
/* correct rcv_wnd as the application won't call tcp_recved()
|
||
for the FIN's seqno */
|
||
if (pcb->rcv_wnd != TCP_WND) {
|
||
pcb->rcv_wnd++;
|
||
}
|
||
|
||
TCP_EVENT_CLOSED(pcb, err);
|
||
if (err == ERR_ABRT) {
|
||
goto aborted;
|
||
}
|
||
}
|
||
|
||
tcp_input_pcb = NULL;//<2F><><EFBFBD><EFBFBD>ȫ<EFBFBD>ֱ<EFBFBD><D6B1><EFBFBD>
|
||
/* Try to send something out. */
|
||
tcp_output(pcb);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
#if TCP_INPUT_DEBUG
|
||
#if TCP_DEBUG
|
||
tcp_debug_print_state(pcb->state);
|
||
#endif /* TCP_DEBUG */
|
||
#endif /* TCP_INPUT_DEBUG */
|
||
}
|
||
}
|
||
/* Jump target if pcb has been aborted in a callback (by calling tcp_abort()).
|
||
Below this line, 'pcb' may not be dereferenced! */
|
||
aborted:
|
||
tcp_input_pcb = NULL;
|
||
recv_data = NULL;
|
||
|
||
/* give up our reference to inseg.p */
|
||
if (inseg.p != NULL)
|
||
{
|
||
pbuf_free(inseg.p);//<2F>ͷ<EFBFBD>buffer
|
||
inseg.p = NULL;
|
||
}
|
||
} else {
|
||
|
||
/* If no matching PCB was found, send a TCP RST (reset) to the
|
||
sender. */
|
||
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_input: no PCB match found, resetting.\n"));
|
||
if (!(TCPH_FLAGS(tcphdr) & TCP_RST)) {
|
||
TCP_STATS_INC(tcp.proterr);//Э<><D0AD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
TCP_STATS_INC(tcp.drop);//tcp<63><70><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
tcp_rst(ackno, seqno + tcplen,
|
||
ip_current_dest_addr(), ip_current_src_addr(),
|
||
tcphdr->dest, tcphdr->src);//<2F><><EFBFBD><EFBFBD>TCP<43><50>λ
|
||
}
|
||
pbuf_free(p);
|
||
}
|
||
|
||
LWIP_ASSERT("tcp_input: tcp_pcbs_sane()", tcp_pcbs_sane());
|
||
PERF_STOP("tcp_input");
|
||
}
|
||
|
||
/**
|
||
* Called by tcp_input() when a segment arrives for a listening
|
||
* connection (from tcp_input()).
|
||
*
|
||
* @param pcb the tcp_pcb_listen for which a segment arrived
|
||
* @return ERR_OK if the segment was processed
|
||
* another err_t on error
|
||
*
|
||
* @note the return value is not (yet?) used in tcp_input()
|
||
* @note the segment which arrived is saved in global variables, therefore only the pcb
|
||
* involved is passed as a parameter to this function
|
||
*/
|
||
/*
|
||
*<2A><><EFBFBD><EFBFBD>LISTEN״̬<D7B4>Ŀ<EFBFBD><C4BF>ƿ<EFBFBD><C6BF><EFBFBD><EFBFBD>øú<C3B8><C3BA><EFBFBD><EFBFBD><EFBFBD>
|
||
*ͨ<><CDA8><EFBFBD>Ƿ<EFBFBD><C7B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD>˿ڲ<CBBF><DAB2><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͻ<EFBFBD><CDBB><EFBFBD>SYN<59><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
*
|
||
*/
|
||
static err_t
|
||
tcp_listen_input(struct tcp_pcb_listen *pcb)
|
||
{
|
||
struct tcp_pcb *npcb;
|
||
struct tcp_pcb *pactive_pcb;
|
||
u8_t active_pcb_num = 0;
|
||
err_t rc;
|
||
|
||
/* In the LISTEN state, we check for incoming SYN segments,
|
||
creates a new PCB, and responds with a SYN|ACK. */
|
||
if (flags & TCP_ACK) {
|
||
/* For incoming segments with the ACK flag set, respond with a
|
||
RST. */
|
||
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_listen_input: ACK in LISTEN, sending reset\n"));
|
||
tcp_rst(ackno + 1, seqno + tcplen,
|
||
ip_current_dest_addr(), ip_current_src_addr(),
|
||
tcphdr->dest, tcphdr->src);
|
||
} else if (flags & TCP_SYN) {//<2F>յ<EFBFBD>SYN<59><4E><EFBFBD><EFBFBD>
|
||
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection request %"U16_F" -> %"U16_F".\n", tcphdr->src, tcphdr->dest));
|
||
#if TCP_LISTEN_BACKLOG
|
||
if (pcb->accepts_pending >= pcb->backlog) {
|
||
LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: listen backlog exceeded for port %"U16_F"\n", tcphdr->dest));
|
||
return ERR_ABRT;
|
||
}
|
||
#endif /* TCP_LISTEN_BACKLOG */
|
||
for(pactive_pcb = tcp_active_pcbs; pactive_pcb != NULL; pactive_pcb = pactive_pcb->next)
|
||
active_pcb_num ++;
|
||
if (active_pcb_num == MEMP_NUM_TCP_PCB){
|
||
LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: exceed the number of active TCP connections\n"));
|
||
TCP_STATS_INC(tcp.memerr);
|
||
return ERR_MEM;
|
||
}
|
||
npcb = tcp_alloc(pcb->prio);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ƿ<EFBFBD>
|
||
/* If a new PCB could not be created (probably due to lack of memory),
|
||
we don't do anything, but rely on the sender will retransmit the
|
||
SYN at a time when we have more memory available. */
|
||
if (npcb == NULL) {
|
||
LWIP_DEBUGF(TCP_DEBUG, ("tcp_listen_input: could not allocate PCB\n"));
|
||
TCP_STATS_INC(tcp.memerr);//TCP<43>ڴ<EFBFBD><DAB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
return ERR_MEM;
|
||
}
|
||
#if TCP_LISTEN_BACKLOG
|
||
pcb->accepts_pending++;
|
||
#endif /* TCP_LISTEN_BACKLOG */
|
||
/* Set up the new PCB. */
|
||
//<2F><><EFBFBD>ƿ<EFBFBD><C6BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ص<EFBFBD>4<EFBFBD><34><EFBFBD>ֶ<EFBFBD>
|
||
ip_addr_copy(npcb->local_ip, current_iphdr_dest);
|
||
npcb->local_port = pcb->local_port;
|
||
ip_addr_copy(npcb->remote_ip, current_iphdr_src);
|
||
npcb->remote_port = tcphdr->src;
|
||
|
||
//<2F><><EFBFBD>ƿ<EFBFBD><C6BF><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֶ<EFBFBD>
|
||
npcb->state = SYN_RCVD;//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>״̬
|
||
npcb->rcv_nxt = seqno + 1;//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
npcb->rcv_ann_right_edge = npcb->rcv_nxt;
|
||
npcb->snd_wnd = tcphdr->wnd;//<2F><><EFBFBD>÷<EFBFBD><C3B7>ʹ<EFBFBD><CDB4><EFBFBD>
|
||
npcb->ssthresh = npcb->snd_wnd;
|
||
npcb->snd_wl1 = seqno - 1;/* initialise to seqno-1 to force window update */
|
||
npcb->callback_arg = pcb->callback_arg;
|
||
#if LWIP_CALLBACK_API
|
||
npcb->accept = pcb->accept;
|
||
#endif /* LWIP_CALLBACK_API */
|
||
/* inherit socket options */
|
||
npcb->so_options = pcb->so_options & SOF_INHERITED;
|
||
/* Register the new PCB so that we can begin receiving segments
|
||
for it. */
|
||
TCP_REG(&tcp_active_pcbs, npcb);
|
||
|
||
/* Parse any options in the SYN. */
|
||
tcp_parseopt(npcb);
|
||
#if TCP_CALCULATE_EFF_SEND_MSS
|
||
npcb->mss = tcp_eff_send_mss(npcb->mss, &(npcb->remote_ip));
|
||
#endif /* TCP_CALCULATE_EFF_SEND_MSS */
|
||
|
||
snmp_inc_tcppassiveopens();
|
||
|
||
/* Send a SYN|ACK together with the MSS option. */
|
||
rc = tcp_enqueue_flags(npcb, TCP_SYN | TCP_ACK);
|
||
if (rc != ERR_OK) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͷ<EFBFBD><CDB7>¿<EFBFBD><C2BF>ƿ<EFBFBD>
|
||
tcp_abandon(npcb, 0);
|
||
return rc;
|
||
}
|
||
return tcp_output(npcb);//<2F><><EFBFBD>ͱ<EFBFBD><CDB1><EFBFBD>
|
||
}
|
||
return ERR_OK;
|
||
}
|
||
|
||
/**
|
||
* Called by tcp_input() when a segment arrives for a connection in
|
||
* TIME_WAIT.
|
||
*
|
||
* @param pcb the tcp_pcb for which a segment arrived
|
||
*
|
||
* @note the segment which arrived is saved in global variables, therefore only the pcb
|
||
* involved is passed as a parameter to this function
|
||
*/
|
||
/*
|
||
*<2A><><EFBFBD><EFBFBD>TIME_WAIT״̬<D7B4>Ŀ<EFBFBD><C4BF>ƿ<EFBFBD><C6BF><EFBFBD><EFBFBD>øú<C3B8><C3BA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>յ<EFBFBD><D5B5>ı<EFBFBD><C4B1>ĶΣ<C4B6>
|
||
*<2A><>״̬<D7B4>£<EFBFBD><C2A3>ر<EFBFBD><D8B1><EFBFBD><EFBFBD>ӵ<EFBFBD><D3B5><EFBFBD><EFBFBD>ֹ<EFBFBD><D6B9><EFBFBD><EFBFBD>Ѿ<EFBFBD><D1BE><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڵȴ<DAB5>2MSL<53><4C>ʱ<EFBFBD><CAB1>
|
||
*<2A><>״̬<D7B4>µı<C2B5><C4B1>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>еľ<D0B5><C4BE><EFBFBD><EFBFBD>ݣ<EFBFBD>ֱ<EFBFBD><D6B1>ɾ<EFBFBD><C9BE><EFBFBD><EFBFBD><EFBFBD>ɡ<EFBFBD>
|
||
*<2A><><EFBFBD><EFBFBD>Ҫ<EFBFBD><D2AA><EFBFBD><EFBFBD><EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD><EFBFBD>ACK<43><4B><EFBFBD><EFBFBD>
|
||
*/
|
||
static err_t
|
||
tcp_timewait_input(struct tcp_pcb *pcb)
|
||
{
|
||
|
||
if (flags & TCP_RST) { //RST<53><54>λ<EFBFBD><CEBB>ֱ<EFBFBD>ӷ<EFBFBD><D3B7><EFBFBD>
|
||
return ERR_OK;
|
||
}
|
||
|
||
if (flags & TCP_SYN) { //<2F><><EFBFBD><EFBFBD>SYN<59><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϣ<EFBFBD><CFA2><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1><EFBFBD><EFBFBD>ڽ<EFBFBD><DABD>մ<EFBFBD><D5B4><EFBFBD><EFBFBD>ڣ<EFBFBD><DAA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͷ<EFBFBD><CDB7><EFBFBD><EFBFBD><EFBFBD>RST<53><54><EFBFBD><EFBFBD>
|
||
|
||
if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt+pcb->rcv_wnd)) {
|
||
|
||
tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
|
||
tcphdr->dest, tcphdr->src);
|
||
return ERR_OK;
|
||
}
|
||
} else if (flags & TCP_FIN) { //<2F><><EFBFBD>İ<EFBFBD><C4B0><EFBFBD>FIN<49><4E><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϣ
|
||
|
||
pcb->tmr = tcp_ticks; //<2F><>λ<EFBFBD>ȴ<EFBFBD>2MSLʱ<4C>䣬<EFBFBD><E4A3AC><EFBFBD>ƿ<EFBFBD><C6BF><EFBFBD><EFBFBD>µȴ<C2B5>2MSL
|
||
}
|
||
|
||
if ((tcplen > 0)) { //<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݵı<DDB5><C4B1>Ļ<EFBFBD><C4BB><EFBFBD><EFBFBD>ڽ<EFBFBD><DABD>մ<EFBFBD><D5B4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>SYN<59><4E><EFBFBD><EFBFBD>
|
||
pcb->flags |= TF_ACK_NOW;//<2F><><EFBFBD><EFBFBD>һ<EFBFBD><D2BB>ACK<43><4B><EFBFBD><EFBFBD>
|
||
return tcp_output(pcb);
|
||
}
|
||
return ERR_OK;
|
||
}
|
||
|
||
/**
|
||
* Implements the TCP state machine. Called by tcp_input. In some
|
||
* states tcp_receive() is called to receive data. The tcp_seg
|
||
* argument will be freed by the caller (tcp_input()) unless the
|
||
* recv_data pointer in the pcb is set.
|
||
*
|
||
* @param pcb the tcp_pcb for which a segment arrived
|
||
*
|
||
* @note the segment which arrived is saved in global variables, therefore only the pcb
|
||
* involved is passed as a parameter to this function
|
||
*/
|
||
static err_t
|
||
tcp_process(struct tcp_pcb *pcb)
|
||
{
|
||
struct tcp_seg *rseg;
|
||
u8_t acceptable = 0;
|
||
err_t err;
|
||
|
||
err = ERR_OK;
|
||
|
||
/* Process incoming RST segments. */
|
||
if (flags & TCP_RST) {
|
||
/* First, determine if the reset is acceptable. */
|
||
if (pcb->state == SYN_SENT) {
|
||
if (ackno == pcb->snd_nxt) {
|
||
acceptable = 1;
|
||
}
|
||
} else {
|
||
if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
|
||
pcb->rcv_nxt+pcb->rcv_wnd)) {
|
||
acceptable = 1;
|
||
}
|
||
}
|
||
|
||
if (acceptable) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: Connection RESET\n"));
|
||
LWIP_ASSERT("tcp_input: pcb->state != CLOSED", pcb->state != CLOSED);
|
||
recv_flags |= TF_RESET;
|
||
pcb->flags &= ~TF_ACK_DELAY;
|
||
return ERR_RST;
|
||
} else {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
|
||
seqno, pcb->rcv_nxt));
|
||
LWIP_DEBUGF(TCP_DEBUG, ("tcp_process: unacceptable reset seqno %"U32_F" rcv_nxt %"U32_F"\n",
|
||
seqno, pcb->rcv_nxt));
|
||
return ERR_OK;
|
||
}
|
||
}
|
||
|
||
if ((flags & TCP_SYN) && (pcb->state != SYN_SENT && pcb->state != SYN_RCVD)) {
|
||
/* Cope with new connection attempt after remote end crashed */
|
||
tcp_ack_now(pcb);
|
||
return ERR_OK;
|
||
}
|
||
|
||
if ((pcb->flags & TF_RXCLOSED) == 0) {
|
||
/* Update the PCB (in)activity timer unless rx is closed (see tcp_shutdown) */
|
||
pcb->tmr = tcp_ticks;
|
||
}
|
||
pcb->keep_cnt_sent = 0;
|
||
|
||
tcp_parseopt(pcb);
|
||
|
||
/* Do different things depending on the TCP state. */
|
||
switch (pcb->state) {
|
||
case SYN_SENT:
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("SYN-SENT: ackno %"U32_F" pcb->snd_nxt %"U32_F" unacked %"U32_F"\n", ackno,
|
||
pcb->snd_nxt, ntohl(pcb->unacked->tcphdr->seqno)));
|
||
/* received SYN ACK with expected sequence number? */
|
||
if ((flags & TCP_ACK) && (flags & TCP_SYN)
|
||
&& ackno == ntohl(pcb->unacked->tcphdr->seqno) + 1) {
|
||
pcb->snd_buf++;
|
||
pcb->rcv_nxt = seqno + 1;
|
||
pcb->rcv_ann_right_edge = pcb->rcv_nxt;
|
||
pcb->lastack = ackno;
|
||
pcb->snd_wnd = tcphdr->wnd;
|
||
pcb->snd_wl1 = seqno - 1; /* initialise to seqno - 1 to force window update */
|
||
pcb->state = ESTABLISHED;
|
||
|
||
#if TCP_CALCULATE_EFF_SEND_MSS
|
||
pcb->mss = tcp_eff_send_mss(pcb->mss, &(pcb->remote_ip));
|
||
#endif /* TCP_CALCULATE_EFF_SEND_MSS */
|
||
|
||
/* Set ssthresh again after changing pcb->mss (already set in tcp_connect
|
||
* but for the default value of pcb->mss) */
|
||
pcb->ssthresh = pcb->mss * 10;
|
||
|
||
pcb->cwnd = ((pcb->cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
|
||
LWIP_ASSERT("pcb->snd_queuelen > 0", (pcb->snd_queuelen > 0));
|
||
--pcb->snd_queuelen;
|
||
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_process: SYN-SENT --queuelen %"U16_F"\n", (u16_t)pcb->snd_queuelen));
|
||
rseg = pcb->unacked;
|
||
pcb->unacked = rseg->next;
|
||
|
||
/* If there's nothing left to acknowledge, stop the retransmit
|
||
timer, otherwise reset it to start again */
|
||
if(pcb->unacked == NULL)
|
||
pcb->rtime = -1;
|
||
else {
|
||
pcb->rtime = 0;
|
||
pcb->nrtx = 0;
|
||
}
|
||
|
||
tcp_seg_free(rseg);
|
||
|
||
/* Call the user specified function to call when sucessfully
|
||
* connected. */
|
||
TCP_EVENT_CONNECTED(pcb, ERR_OK, err);
|
||
if (err == ERR_ABRT) {
|
||
return ERR_ABRT;
|
||
}
|
||
tcp_ack_now(pcb);
|
||
}
|
||
/* received ACK? possibly a half-open connection */
|
||
else if (flags & TCP_ACK) {
|
||
/* send a RST to bring the other side in a non-synchronized state. */
|
||
tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
|
||
tcphdr->dest, tcphdr->src);
|
||
}
|
||
break;
|
||
case SYN_RCVD:
|
||
if (flags & TCP_ACK) {
|
||
/* expected ACK number? */
|
||
if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)) {
|
||
u16_t old_cwnd;
|
||
pcb->state = ESTABLISHED;
|
||
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection established %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
|
||
#if LWIP_CALLBACK_API
|
||
LWIP_ASSERT("pcb->accept != NULL", pcb->accept != NULL);
|
||
#endif
|
||
/* Call the accept function. */
|
||
TCP_EVENT_ACCEPT(pcb, ERR_OK, err);
|
||
if (err != ERR_OK) {
|
||
/* If the accept function returns with an error, we abort
|
||
* the connection. */
|
||
/* Already aborted? */
|
||
if (err != ERR_ABRT) {
|
||
tcp_abort(pcb);
|
||
}
|
||
return ERR_ABRT;
|
||
}
|
||
old_cwnd = pcb->cwnd;
|
||
/* If there was any data contained within this ACK,
|
||
* we'd better pass it on to the application as well. */
|
||
tcp_receive(pcb);
|
||
|
||
/* Prevent ACK for SYN to generate a sent event */
|
||
if (pcb->acked != 0) {
|
||
pcb->acked--;
|
||
}
|
||
|
||
pcb->cwnd = ((old_cwnd == 1) ? (pcb->mss * 2) : pcb->mss);
|
||
|
||
if (recv_flags & TF_GOT_FIN) {
|
||
tcp_ack_now(pcb);
|
||
pcb->state = CLOSE_WAIT;
|
||
}
|
||
} else {
|
||
/* incorrect ACK number, send RST */
|
||
tcp_rst(ackno, seqno + tcplen, ip_current_dest_addr(), ip_current_src_addr(),
|
||
tcphdr->dest, tcphdr->src);
|
||
}
|
||
} else if ((flags & TCP_SYN) && (seqno == pcb->rcv_nxt - 1)) {
|
||
/* Looks like another copy of the SYN - retransmit our SYN-ACK */
|
||
tcp_rexmit(pcb);
|
||
}
|
||
break;
|
||
case CLOSE_WAIT:
|
||
/* FALLTHROUGH */
|
||
case ESTABLISHED:
|
||
tcp_receive(pcb);
|
||
if (recv_flags & TF_GOT_FIN) { /* passive close */
|
||
tcp_ack_now(pcb);
|
||
pcb->state = CLOSE_WAIT;
|
||
}
|
||
break;
|
||
case FIN_WAIT_1:
|
||
tcp_receive(pcb);
|
||
if (recv_flags & TF_GOT_FIN) {
|
||
if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
|
||
LWIP_DEBUGF(TCP_DEBUG,
|
||
("TCP connection closed: FIN_WAIT_1 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
|
||
tcp_ack_now(pcb);
|
||
tcp_pcb_purge(pcb);
|
||
TCP_RMV(&tcp_active_pcbs, pcb);
|
||
pcb->state = TIME_WAIT;
|
||
TCP_REG(&tcp_tw_pcbs, pcb);
|
||
} else {
|
||
tcp_ack_now(pcb);
|
||
pcb->state = CLOSING;
|
||
}
|
||
} else if ((flags & TCP_ACK) && (ackno == pcb->snd_nxt)) {
|
||
pcb->state = FIN_WAIT_2;
|
||
}
|
||
break;
|
||
case FIN_WAIT_2:
|
||
tcp_receive(pcb);
|
||
if (recv_flags & TF_GOT_FIN) {
|
||
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: FIN_WAIT_2 %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
|
||
tcp_ack_now(pcb);
|
||
tcp_pcb_purge(pcb);
|
||
TCP_RMV(&tcp_active_pcbs, pcb);
|
||
pcb->state = TIME_WAIT;
|
||
TCP_REG(&tcp_tw_pcbs, pcb);
|
||
}
|
||
break;
|
||
case CLOSING:
|
||
tcp_receive(pcb);
|
||
if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
|
||
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: CLOSING %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
|
||
tcp_pcb_purge(pcb);
|
||
TCP_RMV(&tcp_active_pcbs, pcb);
|
||
pcb->state = TIME_WAIT;
|
||
TCP_REG(&tcp_tw_pcbs, pcb);
|
||
}
|
||
break;
|
||
case LAST_ACK:
|
||
tcp_receive(pcb);
|
||
if (flags & TCP_ACK && ackno == pcb->snd_nxt) {
|
||
LWIP_DEBUGF(TCP_DEBUG, ("TCP connection closed: LAST_ACK %"U16_F" -> %"U16_F".\n", inseg.tcphdr->src, inseg.tcphdr->dest));
|
||
/* bugfix #21699: don't set pcb->state to CLOSED here or we risk leaking segments */
|
||
recv_flags |= TF_CLOSED;
|
||
}
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
return ERR_OK;
|
||
}
|
||
|
||
#if TCP_QUEUE_OOSEQ
|
||
/**
|
||
* Insert segment into the list (segments covered with new one will be deleted)
|
||
*
|
||
* Called from tcp_receive()
|
||
*/
|
||
static void ICACHE_FLASH_ATTR
|
||
tcp_oos_insert_segment(struct tcp_seg *cseg, struct tcp_seg *next)
|
||
{
|
||
struct tcp_seg *old_seg;
|
||
|
||
if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
|
||
/* received segment overlaps all following segments */
|
||
tcp_segs_free(next);
|
||
next = NULL;
|
||
}
|
||
else {
|
||
/* delete some following segments
|
||
oos queue may have segments with FIN flag */
|
||
while (next &&
|
||
TCP_SEQ_GEQ((seqno + cseg->len),
|
||
(next->tcphdr->seqno + next->len))) {
|
||
/* cseg with FIN already processed */
|
||
if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
|
||
TCPH_SET_FLAG(cseg->tcphdr, TCP_FIN);
|
||
}
|
||
old_seg = next;
|
||
next = next->next;
|
||
tcp_seg_free(old_seg);
|
||
}
|
||
if (next &&
|
||
TCP_SEQ_GT(seqno + cseg->len, next->tcphdr->seqno)) {
|
||
/* We need to trim the incoming segment. */
|
||
cseg->len = (u16_t)(next->tcphdr->seqno - seqno);
|
||
pbuf_realloc(cseg->p, cseg->len);
|
||
}
|
||
}
|
||
cseg->next = next;
|
||
}
|
||
#endif /* TCP_QUEUE_OOSEQ */
|
||
|
||
/**
|
||
* Called by tcp_process. Checks if the given segment is an ACK for outstanding
|
||
* data, and if so frees the memory of the buffered data. Next, is places the
|
||
* segment on any of the receive queues (pcb->recved or pcb->ooseq). If the segment
|
||
* is buffered, the pbuf is referenced by pbuf_ref so that it will not be freed until
|
||
* i it has been removed from the buffer.
|
||
*
|
||
* If the incoming segment constitutes an ACK for a segment that was used for RTT
|
||
* estimation, the RTT is estimated here as well.
|
||
*
|
||
* Called from tcp_process().
|
||
*/
|
||
static void
|
||
tcp_receive(struct tcp_pcb *pcb)
|
||
{
|
||
struct tcp_seg *next;
|
||
#if TCP_QUEUE_OOSEQ
|
||
struct tcp_seg *prev, *cseg;
|
||
#endif /* TCP_QUEUE_OOSEQ */
|
||
struct pbuf *p;
|
||
s32_t off;
|
||
s16_t m;
|
||
u32_t right_wnd_edge;
|
||
u16_t new_tot_len;
|
||
int found_dupack = 0;
|
||
|
||
if (flags & TCP_ACK) {//<2F><><EFBFBD>İ<EFBFBD><C4B0><EFBFBD>ACK
|
||
right_wnd_edge = pcb->snd_wnd + pcb->snd_wl2;//<2F><><EFBFBD>ʹ<EFBFBD><CDB4><EFBFBD> + <20><><EFBFBD><EFBFBD>Ӧ<EFBFBD><D3A6><EFBFBD><EFBFBD><EFBFBD>ڸ<F3B4B0BF><DAB8><EFBFBD>
|
||
|
||
// first /* Update window. */
|
||
/*seqno > snd_wl1<6C><31><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֹ<EFBFBD><D6B9>̲<EFBFBD><CCB2>ô<EFBFBD><C3B4>ָ<EFBFBD><D6B8><EFBFBD>;
|
||
*seqno = snd_wl1<6C><31><EFBFBD><EFBFBD>ackno > snd_wl2;<3B><>ʱ<EFBFBD><CAB1><EFBFBD>Է<EFBFBD>û<EFBFBD>з<EFBFBD><D0B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݣ<EFBFBD>ֻ<EFBFBD><D6BB><EFBFBD>յ<EFBFBD><D5B5><EFBFBD><EFBFBD>ݵ<EFBFBD>ȷ<EFBFBD><C8B7>;
|
||
*ackno = snd_wl2<6C>ұ<EFBFBD><D2B1><EFBFBD><EFBFBD>ײ<EFBFBD><D7B2>б<EFBFBD>snd_wnd<6E><64><EFBFBD><EFBFBD><EFBFBD>Ĵ<EFBFBD><C4B4><EFBFBD>.<2E><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ӧֵ
|
||
*/
|
||
if (TCP_SEQ_LT(pcb->snd_wl1, seqno) ||
|
||
(pcb->snd_wl1 == seqno && TCP_SEQ_LT(pcb->snd_wl2, ackno)) ||
|
||
(pcb->snd_wl2 == ackno && tcphdr->wnd > pcb->snd_wnd)) {
|
||
pcb->snd_wnd = tcphdr->wnd;
|
||
pcb->snd_wl1 = seqno;
|
||
pcb->snd_wl2 = ackno;
|
||
if (pcb->snd_wnd > 0 && pcb->persist_backoff > 0) {
|
||
pcb->persist_backoff = 0;//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʱ<EFBFBD><CAB1><EFBFBD>˳<EFBFBD>
|
||
}
|
||
LWIP_DEBUGF(TCP_WND_DEBUG, ("tcp_receive: window update %"U16_F"\n", pcb->snd_wnd));
|
||
#if TCP_WND_DEBUG
|
||
} else {
|
||
if (pcb->snd_wnd != tcphdr->wnd) {
|
||
LWIP_DEBUGF(TCP_WND_DEBUG,
|
||
("tcp_receive: no window update lastack %"U32_F" ackno %"
|
||
U32_F" wl1 %"U32_F" seqno %"U32_F" wl2 %"U32_F"\n",
|
||
pcb->lastack, ackno, pcb->snd_wl1, seqno, pcb->snd_wl2));
|
||
}
|
||
#endif /* TCP_WND_DEBUG */
|
||
}
|
||
|
||
/* (From Stevens TCP/IP Illustrated Vol II, p970.) Its only a
|
||
* duplicate ack if:
|
||
* 1) It doesn't ACK new data û<><C3BB>ȷ<EFBFBD><C8B7><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
* 2) length of received packet is zero (i.e. no payload) <20><><EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD>κ<EFBFBD><CEBA><EFBFBD><EFBFBD><EFBFBD>
|
||
* 3) the advertised window hasn't changed <20><><EFBFBD>ش<EFBFBD><D8B4><EFBFBD>û<EFBFBD>и<EFBFBD><D0B8><EFBFBD>
|
||
* 4) There is outstanding unacknowledged data (retransmission timer running)<29><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݵȴ<DDB5>ȷ<EFBFBD><C8B7>
|
||
* 5) The ACK is == biggest ACK sequence number so far seen (snd_una) ackno = lastack
|
||
*
|
||
* If it passes all five, should process as a dupack:
|
||
* a) dupacks < 3: do nothing
|
||
* b) dupacks == 3: fast retransmit
|
||
* c) dupacks > 3: increase cwnd
|
||
*
|
||
* If it only passes 1-3, should reset dupack counter (and add to
|
||
* stats, which we don't do in lwIP)
|
||
*
|
||
* If it only passes 1, should reset dupack counter
|
||
*
|
||
*/
|
||
|
||
/* Clause 1 */
|
||
if (TCP_SEQ_LEQ(ackno, pcb->lastack)) {//<2F><><EFBFBD>ظ<EFBFBD>ACK?
|
||
pcb->acked = 0;
|
||
/* Clause 2 */
|
||
if (tcplen == 0) {
|
||
/* Clause 3 */
|
||
if (pcb->snd_wl2 + pcb->snd_wnd == right_wnd_edge){
|
||
/* Clause 4 */
|
||
if (pcb->rtime >= 0) {
|
||
/* Clause 5 */
|
||
if (pcb->lastack == ackno) {
|
||
found_dupack = 1;
|
||
if (pcb->dupacks + 1 > pcb->dupacks)
|
||
++pcb->dupacks;
|
||
if (pcb->dupacks > 3) {
|
||
/* Inflate the congestion window, but not if it means that
|
||
the value overflows. */
|
||
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
|
||
pcb->cwnd += pcb->mss;
|
||
}
|
||
} else if (pcb->dupacks == 3) {//<2F><><EFBFBD>ظ<EFBFBD>ACK
|
||
/* Do fast retransmit */
|
||
tcp_rexmit_fast(pcb);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
/* If Clause (1) or more is true, but not a duplicate ack, reset
|
||
* count of consecutive duplicate acks */
|
||
if (!found_dupack) {
|
||
pcb->dupacks = 0;
|
||
}
|
||
} else if (TCP_SEQ_BETWEEN(ackno, pcb->lastack+1, pcb->snd_nxt)){//ackno<6E><6F>lastack+1<><31>snd_nxt֮<74>䣬<EFBFBD>жϷ<D0B6><CFB7>ʹ<EFBFBD><CDB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
/* We come here when the ACK acknowledges new data. */
|
||
|
||
if (pcb->flags & TF_INFR) {
|
||
pcb->flags &= ~TF_INFR;// Reset the "IN Fast Retransmit" flag,since we are no longer in fast retransmit
|
||
pcb->cwnd = pcb->ssthresh;//Reset the congestion window to the "slow start threshold".
|
||
}
|
||
|
||
/* Reset the number of retransmissions. */
|
||
pcb->nrtx = 0;
|
||
|
||
/* Reset the retransmission time-out. */
|
||
pcb->rto = (pcb->sa >> 3) + pcb->sv;
|
||
|
||
/* Update the send buffer space. Diff between the two can never exceed 64K? */
|
||
pcb->acked = (u16_t)(ackno - pcb->lastack);
|
||
|
||
pcb->snd_buf += pcb->acked;
|
||
|
||
/* Reset the fast retransmit variables. */
|
||
pcb->dupacks = 0;
|
||
pcb->lastack = ackno;
|
||
|
||
/* Update the congestion control variables (cwnd and
|
||
ssthresh). */
|
||
if (pcb->state >= ESTABLISHED) {//״̬Ϊ<CCAC><CEAA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӱ<EFBFBD>־
|
||
if (pcb->cwnd < pcb->ssthresh) {
|
||
if ((u16_t)(pcb->cwnd + pcb->mss) > pcb->cwnd) {
|
||
pcb->cwnd += pcb->mss;
|
||
}
|
||
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: slow start cwnd %"U16_F"\n", pcb->cwnd));
|
||
} else {
|
||
u16_t new_cwnd = (pcb->cwnd + pcb->mss * pcb->mss / pcb->cwnd);
|
||
if (new_cwnd > pcb->cwnd) {
|
||
pcb->cwnd = new_cwnd;
|
||
}
|
||
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_receive: congestion avoidance cwnd %"U16_F"\n", pcb->cwnd));
|
||
}
|
||
}
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: ACK for %"U32_F", unacked->seqno %"U32_F":%"U32_F"\n",
|
||
ackno,
|
||
pcb->unacked != NULL?
|
||
ntohl(pcb->unacked->tcphdr->seqno): 0,
|
||
pcb->unacked != NULL?
|
||
ntohl(pcb->unacked->tcphdr->seqno) + TCP_TCPLEN(pcb->unacked): 0));
|
||
|
||
/* Remove segment from the unacknowledged list if the incoming
|
||
ACK acknowlegdes them.
|
||
*<2A>ͷ<EFBFBD>unacked<65><64><EFBFBD><EFBFBD><EFBFBD>ϱ<EFBFBD>ȷ<EFBFBD>ϵı<CFB5><C4B1>ĶΣ<C4B6>
|
||
*ֱ<><D6B1>unacked<65><64><EFBFBD><EFBFBD>Ϊ<EFBFBD><CEAA>ֹͣ*/
|
||
while (pcb->unacked != NULL &&
|
||
TCP_SEQ_LEQ(ntohl(pcb->unacked->tcphdr->seqno) +
|
||
TCP_TCPLEN(pcb->unacked), ackno)) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unacked\n",
|
||
ntohl(pcb->unacked->tcphdr->seqno),
|
||
ntohl(pcb->unacked->tcphdr->seqno) +
|
||
TCP_TCPLEN(pcb->unacked)));
|
||
|
||
next = pcb->unacked;//pcb unacked<65><64>־
|
||
pcb->unacked = pcb->unacked->next;//pcb unacked <20><>һ<EFBFBD><D2BB><EFBFBD><EFBFBD>־
|
||
|
||
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
|
||
LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
|
||
/* Prevent ACK for FIN to generate a sent event */
|
||
if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
|
||
pcb->acked--;
|
||
}
|
||
|
||
pcb->snd_queuelen -= pbuf_clen(next->p);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>pbufs<66><73><EFBFBD><EFBFBD>
|
||
tcp_seg_free(next);//<2F>ͷ<EFBFBD>tcp<63><70>
|
||
|
||
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unacked)\n", (u16_t)pcb->snd_queuelen));
|
||
if (pcb->snd_queuelen != 0) {
|
||
LWIP_ASSERT("tcp_receive: valid queue length", pcb->unacked != NULL ||
|
||
pcb->unsent != NULL);
|
||
}
|
||
}
|
||
|
||
/* If there's nothing left to acknowledge, stop the retransmit
|
||
timer, otherwise reset it to start again */
|
||
if(pcb->unacked == NULL) //<2F><><EFBFBD><EFBFBD><EFBFBD>ݵȴ<DDB5>ȷ<EFBFBD><C8B7>
|
||
pcb->rtime = -1; //ֹͣ<CDA3>ش<EFBFBD><D8B4><EFBFBD>ʱ<EFBFBD><CAB1>
|
||
else
|
||
pcb->rtime = 0; //<2F><>λ<EFBFBD>ش<EFBFBD><D8B4><EFBFBD>ʱ<EFBFBD><CAB1>
|
||
|
||
pcb->polltmr = 0;
|
||
} else {
|
||
/* Fix bug bug #21582: out of sequence ACK, didn't really ack anything */
|
||
pcb->acked = 0;
|
||
}
|
||
|
||
/* We go through the ->unsent list to see if any of the segments
|
||
on the list are acknowledged by the ACK. This may seem
|
||
strange since an "unsent" segment shouldn't be acked. The
|
||
rationale is that lwIP puts all outstanding segments on the
|
||
->unsent list after a retransmission, so these segments may
|
||
in fact have been sent once. */
|
||
/** unsent<6E><74><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ƿ<EFBFBD><C7B7>ܱ<EFBFBD>acknoȷ<6F>ϵı<CFB5><C4B1>ĶΣ<C4B6><CEA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͷ<EFBFBD>**/
|
||
while (pcb->unsent != NULL &&
|
||
TCP_SEQ_BETWEEN(ackno, ntohl(pcb->unsent->tcphdr->seqno) +
|
||
TCP_TCPLEN(pcb->unsent), pcb->snd_nxt)) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: removing %"U32_F":%"U32_F" from pcb->unsent\n",
|
||
ntohl(pcb->unsent->tcphdr->seqno), ntohl(pcb->unsent->tcphdr->seqno) +
|
||
TCP_TCPLEN(pcb->unsent)));
|
||
|
||
next = pcb->unsent;//pcbδ<62><CEB4><EFBFBD>ͱ<EFBFBD>־
|
||
pcb->unsent = pcb->unsent->next;//δ<><CEB4><EFBFBD>͵<EFBFBD><CDB5><EFBFBD>һ<EFBFBD><D2BB>
|
||
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_receive: queuelen %"U16_F" ... ", (u16_t)pcb->snd_queuelen));
|
||
LWIP_ASSERT("pcb->snd_queuelen >= pbuf_clen(next->p)", (pcb->snd_queuelen >= pbuf_clen(next->p)));
|
||
/* Prevent ACK for FIN to generate a sent event */
|
||
if ((pcb->acked != 0) && ((TCPH_FLAGS(next->tcphdr) & TCP_FIN) != 0)) {
|
||
pcb->acked--;
|
||
}
|
||
pcb->snd_queuelen -= pbuf_clen(next->p);//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>pbuf<75>ĸ<EFBFBD><C4B8><EFBFBD>
|
||
tcp_seg_free(next);//<2F>ͷŶ<CDB7>
|
||
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("%"U16_F" (after freeing unsent)\n", (u16_t)pcb->snd_queuelen));
|
||
if (pcb->snd_queuelen != 0) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>г<EFBFBD><D0B3><EFBFBD>
|
||
LWIP_ASSERT("tcp_receive: valid queue length",
|
||
pcb->unacked != NULL || pcb->unsent != NULL);
|
||
}
|
||
}
|
||
/* End of ACK for new data processing. */
|
||
|
||
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: pcb->rttest %"U32_F" rtseq %"U32_F" ackno %"U32_F"\n",
|
||
pcb->rttest, pcb->rtseq, ackno));
|
||
|
||
/* RTT estimation calculations. This is done by checking if the
|
||
incoming segment acknowledges the segment we use to take a
|
||
round-trip time measurement. */
|
||
if (pcb->rttest && TCP_SEQ_LT(pcb->rtseq, ackno)) {//RTT<54><54><EFBFBD>ڽ<EFBFBD><DABD><EFBFBD><EFBFBD>Ҹñ<D2B8><C3B1>Ķα<C4B6>ȷ<EFBFBD><C8B7>
|
||
/* diff between this shouldn't exceed 32K since this are tcp timer ticks
|
||
and a round-trip shouldn't be that long... */
|
||
m = (s16_t)(tcp_ticks - pcb->rttest);//<2F><><EFBFBD><EFBFBD>Mֵ
|
||
|
||
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: experienced rtt %"U16_F" ticks (%"U16_F" msec).\n",
|
||
m, m * TCP_SLOW_INTERVAL));
|
||
|
||
/* This is taken directly from VJs original code in his paper <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>RTT<54><54><EFBFBD>㹫ʽ*/
|
||
m = m - (pcb->sa >> 3);
|
||
pcb->sa += m;
|
||
if (m < 0) {
|
||
m = -m;
|
||
}
|
||
m = m - (pcb->sv >> 2);
|
||
pcb->sv += m;
|
||
pcb->rto = (pcb->sa >> 3) + pcb->sv;
|
||
|
||
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_receive: RTO %"U16_F" (%"U16_F" milliseconds)\n",
|
||
pcb->rto, pcb->rto * TCP_SLOW_INTERVAL));
|
||
|
||
pcb->rttest = 0;
|
||
}
|
||
}
|
||
|
||
/* If the incoming segment contains data, we must process it
|
||
further. */
|
||
if (tcplen > 0) {
|
||
/* This code basically does three things:
|
||
|
||
+) If the incoming segment contains data that is the next
|
||
in-sequence data, this data is passed to the application. This
|
||
might involve trimming the first edge of the data. The rcv_nxt
|
||
variable and the advertised window are adjusted.
|
||
|
||
+) If the incoming segment has data that is above the next
|
||
sequence number expected (->rcv_nxt), the segment is placed on
|
||
the ->ooseq queue. This is done by finding the appropriate
|
||
place in the ->ooseq queue (which is ordered by sequence
|
||
number) and trim the segment in both ends if needed. An
|
||
immediate ACK is sent to indicate that we received an
|
||
out-of-sequence segment.
|
||
|
||
+) Finally, we check if the first segment on the ->ooseq queue
|
||
now is in sequence (i.e., if rcv_nxt >= ooseq->seqno). If
|
||
rcv_nxt > ooseq->seqno, we must trim the first edge of the
|
||
segment on ->ooseq before we adjust rcv_nxt. The data in the
|
||
segments that are now on sequence are chained onto the
|
||
incoming segment so that we only need to call the application
|
||
once.
|
||
*/
|
||
|
||
/* First, we check if we must trim the first edge. We have to do
|
||
this if the sequence number of the incoming segment is less
|
||
than rcv_nxt, and the sequence number plus the length of the
|
||
segment is larger than rcv_nxt. */
|
||
/* if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){
|
||
if (TCP_SEQ_LT(pcb->rcv_nxt, seqno + tcplen)) {*/
|
||
if (TCP_SEQ_BETWEEN(pcb->rcv_nxt, seqno + 1, seqno + tcplen - 1)){// seqno < rcv_nxt < seqno + tcplen
|
||
/* Trimming the first edge is done by pushing the payload
|
||
pointer in the pbuf downwards. This is somewhat tricky since
|
||
we do not want to discard the full contents of the pbuf up to
|
||
the new starting point of the data since we have to keep the
|
||
TCP header which is present in the first pbuf in the chain.
|
||
|
||
What is done is really quite a nasty hack: the first pbuf in
|
||
the pbuf chain is pointed to by inseg.p. Since we need to be
|
||
able to deallocate the whole pbuf, we cannot change this
|
||
inseg.p pointer to point to any of the later pbufs in the
|
||
chain. Instead, we point the ->payload pointer in the first
|
||
pbuf to data in one of the later pbufs. We also set the
|
||
inseg.data pointer to point to the right place. This way, the
|
||
->p pointer will still point to the first pbuf, but the
|
||
->p->payload pointer will point to data in another pbuf.
|
||
|
||
After we are done with adjusting the pbuf pointers we must
|
||
adjust the ->data pointer in the seg and the segment
|
||
length.*/
|
||
//ȥ<><C8A5><EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1>ŵ<EFBFBD><C5B5><EFBFBD>rcv_nxt<78><74><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
|
||
off = pcb->rcv_nxt - seqno;
|
||
p = inseg.p;
|
||
LWIP_ASSERT("inseg.p != NULL", inseg.p);
|
||
LWIP_ASSERT("insane offset!", (off < 0x7fff));
|
||
if (inseg.p->len < off) {
|
||
LWIP_ASSERT("pbuf too short!", (((s32_t)inseg.p->tot_len) >= off));
|
||
new_tot_len = (u16_t)(inseg.p->tot_len - off);
|
||
while (p->len < off) {
|
||
off -= p->len;
|
||
/* KJM following line changed (with addition of new_tot_len var)
|
||
to fix bug #9076
|
||
inseg.p->tot_len -= p->len; */
|
||
p->tot_len = new_tot_len;
|
||
p->len = 0;
|
||
p = p->next;
|
||
}
|
||
if(pbuf_header(p, (s16_t)-off)) {
|
||
/* Do we need to cope with this failing? Assert for now */
|
||
LWIP_ASSERT("pbuf_header failed", 0);
|
||
}
|
||
} else {
|
||
if(pbuf_header(inseg.p, (s16_t)-off)) {
|
||
/* Do we need to cope with this failing? Assert for now */
|
||
LWIP_ASSERT("pbuf_header failed", 0);
|
||
}
|
||
}
|
||
inseg.len -= (u16_t)(pcb->rcv_nxt - seqno);
|
||
inseg.tcphdr->seqno = seqno = pcb->rcv_nxt;
|
||
}
|
||
else {
|
||
if (TCP_SEQ_LT(seqno, pcb->rcv_nxt)){//seqno < rcv_nxt
|
||
/* the whole segment is < rcv_nxt */
|
||
/* must be a duplicate of a packet that has already been correctly handled */
|
||
//<2F><><EFBFBD>Ķ<EFBFBD><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݱ<EFBFBD><DDB1>ž<EFBFBD>С<EFBFBD><D0A1>rcv_nxt<78><74><EFBFBD><EFBFBD><EFBFBD>˱<EFBFBD><CBB1><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ظ<EFBFBD><D8B8><EFBFBD><EFBFBD>ģ<EFBFBD>
|
||
//ֱ<><D6B1><EFBFBD><EFBFBD>Դ<EFBFBD><D4B4><EFBFBD><EFBFBD>ӦACK<43><4B><EFBFBD>Ĵ<EFBFBD><C4B4><EFBFBD>
|
||
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: duplicate seqno %"U32_F"\n", seqno));
|
||
tcp_ack_now(pcb);
|
||
}
|
||
}
|
||
|
||
/* The sequence number must be within the window (above rcv_nxt
|
||
and below rcv_nxt + rcv_wnd) in order to be further
|
||
processed. */
|
||
if (TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt,
|
||
pcb->rcv_nxt + pcb->rcv_wnd - 1)){//rcv_nxt < seqno < rcv_nxt + rcv_wnd - 1,<2C><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ڽ<EFBFBD><DABD>շ<EFBFBD>Χ<EFBFBD><CEA7>
|
||
if (pcb->rcv_nxt == seqno) {
|
||
/* The incoming segment is the next in sequence. We check if
|
||
we have to trim the end of the segment and update rcv_nxt
|
||
and pass the data to the application. */
|
||
tcplen = TCP_TCPLEN(&inseg);//<2F><><EFBFBD>㱨<EFBFBD>Ķγ<C4B6><CEB3><EFBFBD>
|
||
|
||
if (tcplen > pcb->rcv_wnd) {//<2F><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>մ<EFBFBD><D5B4>ڴ<EFBFBD>С<EFBFBD><D0A1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>β<EFBFBD><CEB2><EFBFBD>ض<EFBFBD>
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG,
|
||
("tcp_receive: other end overran receive window"
|
||
"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
|
||
seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
|
||
if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
|
||
/* Must remove the FIN from the header as we're trimming
|
||
* that byte of sequence-space from the packet */
|
||
TCPH_FLAGS_SET(inseg.tcphdr, TCPH_FLAGS(inseg.tcphdr) &~ TCP_FIN);
|
||
}
|
||
/* Adjust length of segment to fit in the window. */
|
||
inseg.len = pcb->rcv_wnd;
|
||
if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
|
||
inseg.len -= 1;
|
||
}
|
||
pbuf_realloc(inseg.p, inseg.len);
|
||
tcplen = TCP_TCPLEN(&inseg);
|
||
LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
|
||
(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
|
||
}
|
||
#if TCP_QUEUE_OOSEQ
|
||
/* Received in-sequence data, adjust ooseq data if:
|
||
- FIN has been received or
|
||
- inseq overlaps with ooseq */
|
||
if (pcb->ooseq != NULL) {
|
||
if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG,
|
||
("tcp_receive: received in-order FIN, binning ooseq queue\n"));
|
||
/* Received in-order FIN means anything that was received
|
||
* out of order must now have been received in-order, so
|
||
* bin the ooseq queue */
|
||
while (pcb->ooseq != NULL) {
|
||
struct tcp_seg *old_ooseq = pcb->ooseq;
|
||
pcb->ooseq = pcb->ooseq->next;
|
||
tcp_seg_free(old_ooseq);
|
||
}
|
||
}
|
||
else {
|
||
next = pcb->ooseq;
|
||
/* Remove all segments on ooseq that are covered by inseg already.
|
||
* FIN is copied from ooseq to inseg if present. */
|
||
while (next &&
|
||
TCP_SEQ_GEQ(seqno + tcplen,
|
||
next->tcphdr->seqno + next->len)) {
|
||
/* inseg cannot have FIN here (already processed above) */
|
||
if (TCPH_FLAGS(next->tcphdr) & TCP_FIN &&
|
||
(TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) == 0) {
|
||
TCPH_SET_FLAG(inseg.tcphdr, TCP_FIN);
|
||
tcplen = TCP_TCPLEN(&inseg);
|
||
}
|
||
prev = next;
|
||
next = next->next;
|
||
tcp_seg_free(prev);
|
||
}
|
||
/* Now trim right side of inseg if it overlaps with the first
|
||
* segment on ooseq */
|
||
if (next &&
|
||
TCP_SEQ_GT(seqno + tcplen,
|
||
next->tcphdr->seqno)) {
|
||
/* inseg cannot have FIN here (already processed above) */
|
||
inseg.len = (u16_t)(next->tcphdr->seqno - seqno);
|
||
if (TCPH_FLAGS(inseg.tcphdr) & TCP_SYN) {
|
||
inseg.len -= 1;
|
||
}
|
||
pbuf_realloc(inseg.p, inseg.len);
|
||
tcplen = TCP_TCPLEN(&inseg);
|
||
LWIP_ASSERT("tcp_receive: segment not trimmed correctly to ooseq queue\n",
|
||
(seqno + tcplen) == next->tcphdr->seqno);
|
||
}
|
||
pcb->ooseq = next;
|
||
}
|
||
}
|
||
#endif /* TCP_QUEUE_OOSEQ */
|
||
|
||
pcb->rcv_nxt = seqno + tcplen;
|
||
|
||
/* Update the receiver's (our) window. */
|
||
LWIP_ASSERT("tcp_receive: tcplen > rcv_wnd\n", pcb->rcv_wnd >= tcplen);
|
||
pcb->rcv_wnd -= tcplen;
|
||
|
||
tcp_update_rcv_ann_wnd(pcb);
|
||
|
||
/* If there is data in the segment, we make preparations to
|
||
pass this up to the application. The ->recv_data variable
|
||
is used for holding the pbuf that goes to the
|
||
application. The code for reassembling out-of-sequence data
|
||
chains its data on this pbuf as well.
|
||
|
||
If the segment was a FIN, we set the TF_GOT_FIN flag that will
|
||
be used to indicate to the application that the remote side has
|
||
closed its end of the connection. */
|
||
if (inseg.p->tot_len > 0) {
|
||
recv_data = inseg.p;
|
||
/* Since this pbuf now is the responsibility of the
|
||
application, we delete our reference to it so that we won't
|
||
(mistakingly) deallocate it. */
|
||
inseg.p = NULL;
|
||
}
|
||
if (TCPH_FLAGS(inseg.tcphdr) & TCP_FIN) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: received FIN.\n"));
|
||
recv_flags |= TF_GOT_FIN;
|
||
}
|
||
|
||
#if TCP_QUEUE_OOSEQ
|
||
/* We now check if we have segments on the ->ooseq queue that
|
||
are now in sequence. */
|
||
while (pcb->ooseq != NULL &&
|
||
pcb->ooseq->tcphdr->seqno == pcb->rcv_nxt) {
|
||
|
||
cseg = pcb->ooseq;
|
||
seqno = pcb->ooseq->tcphdr->seqno;
|
||
|
||
pcb->rcv_nxt += TCP_TCPLEN(cseg);
|
||
LWIP_ASSERT("tcp_receive: ooseq tcplen > rcv_wnd\n",
|
||
pcb->rcv_wnd >= TCP_TCPLEN(cseg));
|
||
pcb->rcv_wnd -= TCP_TCPLEN(cseg);
|
||
|
||
tcp_update_rcv_ann_wnd(pcb);
|
||
|
||
if (cseg->p->tot_len > 0) {
|
||
/* Chain this pbuf onto the pbuf that we will pass to
|
||
the application. */
|
||
if (recv_data) {
|
||
pbuf_cat(recv_data, cseg->p);
|
||
} else {
|
||
recv_data = cseg->p;
|
||
}
|
||
cseg->p = NULL;
|
||
}
|
||
if (TCPH_FLAGS(cseg->tcphdr) & TCP_FIN) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_receive: dequeued FIN.\n"));
|
||
recv_flags |= TF_GOT_FIN;
|
||
if (pcb->state == ESTABLISHED) { /* force passive close or we can move to active close */
|
||
pcb->state = CLOSE_WAIT;
|
||
}
|
||
}
|
||
|
||
pcb->ooseq = cseg->next;
|
||
tcp_seg_free(cseg);
|
||
}
|
||
#endif /* TCP_QUEUE_OOSEQ */
|
||
|
||
|
||
/* Acknowledge the segment(s). */
|
||
tcp_ack(pcb);
|
||
|
||
} else {
|
||
/* We get here if the incoming segment is out-of-sequence. */
|
||
tcp_send_empty_ack(pcb);
|
||
#if TCP_QUEUE_OOSEQ
|
||
/* We queue the segment on the ->ooseq queue. */
|
||
if (pcb->ooseq == NULL) {
|
||
pcb->ooseq = tcp_seg_copy(&inseg);
|
||
} else {
|
||
/* If the queue is not empty, we walk through the queue and
|
||
try to find a place where the sequence number of the
|
||
incoming segment is between the sequence numbers of the
|
||
previous and the next segment on the ->ooseq queue. That is
|
||
the place where we put the incoming segment. If needed, we
|
||
trim the second edges of the previous and the incoming
|
||
segment so that it will fit into the sequence.
|
||
|
||
If the incoming segment has the same sequence number as a
|
||
segment on the ->ooseq queue, we discard the segment that
|
||
contains less data. */
|
||
|
||
prev = NULL;
|
||
for(next = pcb->ooseq; next != NULL; next = next->next) {//<2F><>ooseqȡ<71>µ<EFBFBD>M<EFBFBD><4D><EFBFBD><EFBFBD><EFBFBD>ĶΣ<C4B6><CEA3>ñ<EFBFBD><C3B1>Ķηǿգ<C7BF>M++
|
||
if (seqno == next->tcphdr->seqno) {//<2F>ñ<EFBFBD><C3B1>Ķ<EFBFBD><C4B6><EFBFBD>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD>== Ҫ<><D2AA><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1>Ķα<C4B6><CEB1><EFBFBD>
|
||
/* The sequence number of the incoming segment is the
|
||
same as the sequence number of the segment on
|
||
->ooseq. We check the lengths to see which one to
|
||
discard. */
|
||
if (inseg.len > next->len) {//Ҫ<><D2AA><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1>Ķα<C4B6><CEB1>Ÿ<EFBFBD><C5B8><EFBFBD>
|
||
/* The incoming segment is larger than the old
|
||
segment. We replace some segments with the new
|
||
one. */
|
||
cseg = tcp_seg_copy(&inseg);//Ҫ<><D2AA><EFBFBD><EFBFBD><EFBFBD>ı<EFBFBD><C4B1>Ķδ<C4B6><CEB4><EFBFBD><EFBFBD><EFBFBD>M<EFBFBD><4D><EFBFBD><EFBFBD><EFBFBD>Ķ<EFBFBD>
|
||
if (cseg != NULL) {
|
||
if (prev != NULL) {
|
||
prev->next = cseg;
|
||
} else {
|
||
pcb->ooseq = cseg;
|
||
}
|
||
tcp_oos_insert_segment(cseg, next);
|
||
}
|
||
break;
|
||
} else {
|
||
/* Either the lenghts are the same or the incoming
|
||
segment was smaller than the old one; in either
|
||
case, we ditch the incoming segment. */
|
||
break;
|
||
}
|
||
} else {
|
||
if (prev == NULL) {
|
||
if (TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {
|
||
/* The sequence number of the incoming segment is lower
|
||
than the sequence number of the first segment on the
|
||
queue. We put the incoming segment first on the
|
||
queue. */
|
||
cseg = tcp_seg_copy(&inseg);
|
||
if (cseg != NULL) {
|
||
pcb->ooseq = cseg;
|
||
tcp_oos_insert_segment(cseg, next);
|
||
}
|
||
break;
|
||
}
|
||
} else {
|
||
/*if (TCP_SEQ_LT(prev->tcphdr->seqno, seqno) &&
|
||
TCP_SEQ_LT(seqno, next->tcphdr->seqno)) {*/
|
||
if (TCP_SEQ_BETWEEN(seqno, prev->tcphdr->seqno+1, next->tcphdr->seqno-1)) {
|
||
/* The sequence number of the incoming segment is in
|
||
between the sequence numbers of the previous and
|
||
the next segment on ->ooseq. We trim trim the previous
|
||
segment, delete next segments that included in received segment
|
||
and trim received, if needed. */
|
||
cseg = tcp_seg_copy(&inseg);
|
||
if (cseg != NULL) {
|
||
if (TCP_SEQ_GT(prev->tcphdr->seqno + prev->len, seqno)) {
|
||
/* We need to trim the prev segment. */
|
||
prev->len = (u16_t)(seqno - prev->tcphdr->seqno);
|
||
pbuf_realloc(prev->p, prev->len);
|
||
}
|
||
prev->next = cseg;
|
||
tcp_oos_insert_segment(cseg, next);
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
/* If the "next" segment is the last segment on the
|
||
ooseq queue, we add the incoming segment to the end
|
||
of the list. */
|
||
if (next->next == NULL &&
|
||
TCP_SEQ_GT(seqno, next->tcphdr->seqno)) {
|
||
if (TCPH_FLAGS(next->tcphdr) & TCP_FIN) {
|
||
/* segment "next" already contains all data */
|
||
break;
|
||
}
|
||
next->next = tcp_seg_copy(&inseg);
|
||
if (next->next != NULL) {
|
||
if (TCP_SEQ_GT(next->tcphdr->seqno + next->len, seqno)) {
|
||
/* We need to trim the last segment. */
|
||
next->len = (u16_t)(seqno - next->tcphdr->seqno);
|
||
pbuf_realloc(next->p, next->len);
|
||
}
|
||
/* check if the remote side overruns our receive window */
|
||
if ((u32_t)tcplen + seqno > pcb->rcv_nxt + (u32_t)pcb->rcv_wnd) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG,
|
||
("tcp_receive: other end overran receive window"
|
||
"seqno %"U32_F" len %"U16_F" right edge %"U32_F"\n",
|
||
seqno, tcplen, pcb->rcv_nxt + pcb->rcv_wnd));
|
||
if (TCPH_FLAGS(next->next->tcphdr) & TCP_FIN) {
|
||
/* Must remove the FIN from the header as we're trimming
|
||
* that byte of sequence-space from the packet */
|
||
TCPH_FLAGS_SET(next->next->tcphdr, TCPH_FLAGS(next->next->tcphdr) &~ TCP_FIN);
|
||
}
|
||
/* Adjust length of segment to fit in the window. */
|
||
next->next->len = pcb->rcv_nxt + pcb->rcv_wnd - seqno;
|
||
pbuf_realloc(next->next->p, next->next->len);
|
||
tcplen = TCP_TCPLEN(next->next);
|
||
LWIP_ASSERT("tcp_receive: segment not trimmed correctly to rcv_wnd\n",
|
||
(seqno + tcplen) == (pcb->rcv_nxt + pcb->rcv_wnd));
|
||
}
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
prev = next;
|
||
}
|
||
}
|
||
#endif /* TCP_QUEUE_OOSEQ */
|
||
|
||
}
|
||
} else {
|
||
/* The incoming segment is not withing the window. */
|
||
tcp_send_empty_ack(pcb);
|
||
}
|
||
} else {
|
||
/* Segments with length 0 is taken care of here. Segments that
|
||
fall out of the window are ACKed. */
|
||
/*if (TCP_SEQ_GT(pcb->rcv_nxt, seqno) ||
|
||
TCP_SEQ_GEQ(seqno, pcb->rcv_nxt + pcb->rcv_wnd)) {*/
|
||
if(!TCP_SEQ_BETWEEN(seqno, pcb->rcv_nxt, pcb->rcv_nxt + pcb->rcv_wnd-1)){
|
||
tcp_ack_now(pcb);//<2F><>Դ<EFBFBD>˷<EFBFBD><CBB7><EFBFBD>һ<EFBFBD><D2BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȷ<EFBFBD>ϱ<EFBFBD><CFB1><EFBFBD>
|
||
}
|
||
}
|
||
}
|
||
|
||
/**
|
||
* Parses the options contained in the incoming segment.
|
||
*
|
||
* Called from tcp_listen_input() and tcp_process().
|
||
* Currently, only the MSS option is supported!
|
||
*
|
||
* @param pcb the tcp_pcb for which a segment arrived
|
||
*/
|
||
static void
|
||
tcp_parseopt(struct tcp_pcb *pcb)
|
||
{
|
||
u16_t c, max_c;
|
||
u16_t mss;
|
||
u8_t *opts, opt;
|
||
#if LWIP_TCP_TIMESTAMPS
|
||
u32_t tsval;
|
||
#endif
|
||
|
||
opts = (u8_t *)tcphdr + TCP_HLEN;
|
||
|
||
/* Parse the TCP MSS option, if present. */
|
||
if(TCPH_HDRLEN(tcphdr) > 0x5) {
|
||
max_c = (TCPH_HDRLEN(tcphdr) - 5) << 2;
|
||
for (c = 0; c < max_c; ) {
|
||
opt = opts[c];
|
||
switch (opt) {
|
||
case 0x00:
|
||
/* End of options. */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: EOL\n"));
|
||
return;
|
||
case 0x01:
|
||
/* NOP option. */
|
||
++c;
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: NOP\n"));
|
||
break;
|
||
case 0x02:
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: MSS\n"));
|
||
if (opts[c + 1] != 0x04 || c + 0x04 > max_c) {
|
||
/* Bad length */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
|
||
return;
|
||
}
|
||
/* An MSS option with the right option length. */
|
||
mss = (opts[c + 2] << 8) | opts[c + 3];
|
||
/* Limit the mss to the configured TCP_MSS and prevent division by zero */
|
||
pcb->mss = ((mss > TCP_MSS) || (mss == 0)) ? TCP_MSS : mss;
|
||
/* Advance to next option */
|
||
c += 0x04;
|
||
break;
|
||
#if LWIP_TCP_TIMESTAMPS
|
||
case 0x08:
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: TS\n"));
|
||
if (opts[c + 1] != 0x0A || c + 0x0A > max_c) {
|
||
/* Bad length */
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
|
||
return;
|
||
}
|
||
/* TCP timestamp option with valid length */
|
||
tsval = (opts[c+2]) | (opts[c+3] << 8) |
|
||
(opts[c+4] << 16) | (opts[c+5] << 24);
|
||
if (flags & TCP_SYN) {
|
||
pcb->ts_recent = ntohl(tsval);
|
||
pcb->flags |= TF_TIMESTAMP;
|
||
} else if (TCP_SEQ_BETWEEN(pcb->ts_lastacksent, seqno, seqno+tcplen)) {
|
||
pcb->ts_recent = ntohl(tsval);
|
||
}
|
||
/* Advance to next option */
|
||
c += 0x0A;
|
||
break;
|
||
#endif
|
||
default:
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: other\n"));
|
||
if (opts[c + 1] == 0) {
|
||
LWIP_DEBUGF(TCP_INPUT_DEBUG, ("tcp_parseopt: bad length\n"));
|
||
/* If the length field is zero, the options are malformed
|
||
and we don't process them further. */
|
||
return;
|
||
}
|
||
/* All other options have a length field, so that we easily
|
||
can skip past them. */
|
||
c += opts[c + 1];
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#endif /* LWIP_TCP */
|