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1515 lines
46 KiB
C
1515 lines
46 KiB
C
/**
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* \addtogroup uip
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* @{
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*/
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/**
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* \file
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* The uIP TCP/IP stack code.
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* \author Adam Dunkels <adam@dunkels.com>
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*/
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/*
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* Copyright (c) 2001-2003, Adam Dunkels.
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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
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation 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
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* This file is part of the uIP TCP/IP stack.
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*
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* $Id: uip.c,v 1.62.2.10 2003/10/07 13:23:01 adam Exp $
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*
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*/
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/*
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This is a small implementation of the IP and TCP protocols (as well as
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some basic ICMP stuff). The implementation couples the IP, TCP and the
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application layers very tightly. To keep the size of the compiled code
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down, this code also features heavy usage of the goto statement.
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The principle is that we have a small buffer, called the uip_buf, in
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which the device driver puts an incoming packet. The TCP/IP stack
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parses the headers in the packet, and calls upon the application. If
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the remote host has sent data to the application, this data is present
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in the uip_buf and the application read the data from there. It is up
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to the application to put this data into a byte stream if needed. The
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application will not be fed with data that is out of sequence.
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If the application whishes to send data to the peer, it should put its
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data into the uip_buf, 40 bytes from the start of the buffer. The
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TCP/IP stack will calculate the checksums, and fill in the necessary
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header fields and finally send the packet back to the peer.
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*/
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#include "uip.h"
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#include "uipopt.h"
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#include "uip_arch.h"
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/*-----------------------------------------------------------------------------------*/
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/* Variable definitions. */
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/* The IP address of this host. If it is defined to be fixed (by setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set here. Otherwise, the address */
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#if UIP_FIXEDADDR > 0
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const u16_t uip_hostaddr[2] =
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{HTONS((UIP_IPADDR0 << 8) | UIP_IPADDR1),
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HTONS((UIP_IPADDR2 << 8) | UIP_IPADDR3)};
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const u16_t uip_arp_draddr[2] =
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{HTONS((UIP_DRIPADDR0 << 8) | UIP_DRIPADDR1),
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HTONS((UIP_DRIPADDR2 << 8) | UIP_DRIPADDR3)};
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const u16_t uip_arp_netmask[2] =
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{HTONS((UIP_NETMASK0 << 8) | UIP_NETMASK1),
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HTONS((UIP_NETMASK2 << 8) | UIP_NETMASK3)};
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#else
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u16_t uip_hostaddr[2];
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u16_t uip_arp_draddr[2], uip_arp_netmask[2];
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#endif /* UIP_FIXEDADDR */
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u8_t uip_buf[UIP_BUFSIZE+2]; /* The packet buffer that contains
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incoming packets. */
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volatile u8_t *uip_appdata; /* The uip_appdata pointer points to
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application data. */
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volatile u8_t *uip_sappdata; /* The uip_appdata pointer points to the
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application data which is to be sent. */
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#if UIP_URGDATA > 0
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volatile u8_t *uip_urgdata; /* The uip_urgdata pointer points to
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urgent data (out-of-band data), if
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present. */
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volatile u8_t uip_urglen, uip_surglen;
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#endif /* UIP_URGDATA > 0 */
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volatile u16_t uip_len, uip_slen;
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/* The uip_len is either 8 or 16 bits,
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depending on the maximum packet
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size. */
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volatile u8_t uip_flags; /* The uip_flags variable is used for
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communication between the TCP/IP stack
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and the application program. */
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struct uip_conn *uip_conn; /* uip_conn always points to the current
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connection. */
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struct uip_conn uip_conns[UIP_CONNS];
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/* The uip_conns array holds all TCP
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connections. */
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u16_t uip_listenports[UIP_LISTENPORTS];
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/* The uip_listenports list all currently
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listning ports. */
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#if UIP_UDP
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struct uip_udp_conn *uip_udp_conn;
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struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
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#endif /* UIP_UDP */
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static u16_t ipid; /* Ths ipid variable is an increasing
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number that is used for the IP ID
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field. */
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static u8_t iss[4]; /* The iss variable is used for the TCP
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initial sequence number. */
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#if UIP_ACTIVE_OPEN
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static u16_t lastport; /* Keeps track of the last port used for
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a new connection. */
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#endif /* UIP_ACTIVE_OPEN */
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/* Temporary variables. */
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volatile u8_t uip_acc32[4];
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static u8_t c, opt;
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static u16_t tmp16;
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/* Structures and definitions. */
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#define TCP_FIN 0x01
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#define TCP_SYN 0x02
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#define TCP_RST 0x04
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#define TCP_PSH 0x08
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#define TCP_ACK 0x10
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#define TCP_URG 0x20
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#define TCP_CTL 0x3f
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#define ICMP_ECHO_REPLY 0
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#define ICMP_ECHO 8
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/* Macros. */
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#define BUF ((uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#define FBUF ((uip_tcpip_hdr *)&uip_reassbuf[0])
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#define ICMPBUF ((uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#define UDPBUF ((uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#if UIP_STATISTICS == 1
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struct uip_stats uip_stat;
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#define UIP_STAT(s) s
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#else
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#define UIP_STAT(s)
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#endif /* UIP_STATISTICS == 1 */
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#if UIP_LOGGING == 1
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#include <stdio.h>
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void uip_log(char *msg);
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#define UIP_LOG(m) uip_log(m)
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#else
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#define UIP_LOG(m)
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#endif /* UIP_LOGGING == 1 */
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/*-----------------------------------------------------------------------------------*/
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void
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uip_init(void)
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{
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for(c = 0; c < UIP_LISTENPORTS; ++c) {
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uip_listenports[c] = 0;
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}
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for(c = 0; c < UIP_CONNS; ++c) {
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uip_conns[c].tcpstateflags = CLOSED;
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}
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#if UIP_ACTIVE_OPEN
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lastport = 1024;
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#endif /* UIP_ACTIVE_OPEN */
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#if UIP_UDP
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for(c = 0; c < UIP_UDP_CONNS; ++c) {
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uip_udp_conns[c].lport = 0;
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}
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#endif /* UIP_UDP */
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/* IPv4 initialization. */
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#if UIP_FIXEDADDR == 0
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uip_hostaddr[0] = uip_hostaddr[1] = 0;
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#endif /* UIP_FIXEDADDR */
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}
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/*-----------------------------------------------------------------------------------*/
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#if UIP_ACTIVE_OPEN
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struct uip_conn *
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uip_connect(u16_t *ripaddr, u16_t rport)
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{
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register struct uip_conn *conn, *cconn;
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/* Find an unused local port. */
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again:
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++lastport;
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if(lastport >= 32000) {
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lastport = 4096;
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}
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/* Check if this port is already in use, and if so try to find
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another one. */
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for(c = 0; c < UIP_CONNS; ++c) {
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conn = &uip_conns[c];
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if(conn->tcpstateflags != CLOSED &&
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conn->lport == htons(lastport)) {
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goto again;
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}
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}
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conn = 0;
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for(c = 0; c < UIP_CONNS; ++c) {
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cconn = &uip_conns[c];
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if(cconn->tcpstateflags == CLOSED) {
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conn = cconn;
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break;
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}
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if(cconn->tcpstateflags == TIME_WAIT) {
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if(conn == 0 ||
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cconn->timer > uip_conn->timer) {
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conn = cconn;
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}
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}
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}
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if(conn == 0) {
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return 0;
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}
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conn->tcpstateflags = SYN_SENT;
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conn->snd_nxt[0] = iss[0];
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conn->snd_nxt[1] = iss[1];
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conn->snd_nxt[2] = iss[2];
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conn->snd_nxt[3] = iss[3];
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conn->initialmss = conn->mss = UIP_TCP_MSS;
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conn->len = 1; /* TCP length of the SYN is one. */
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conn->nrtx = 0;
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conn->timer = 1; /* Send the SYN next time around. */
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conn->rto = UIP_RTO;
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conn->sa = 0;
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conn->sv = 16;
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conn->lport = htons(lastport);
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conn->rport = rport;
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conn->ripaddr[0] = ripaddr[0];
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conn->ripaddr[1] = ripaddr[1];
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return conn;
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}
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#endif /* UIP_ACTIVE_OPEN */
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/*-----------------------------------------------------------------------------------*/
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#if UIP_UDP
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struct uip_udp_conn *
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uip_udp_new(u16_t *ripaddr, u16_t rport)
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{
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register struct uip_udp_conn *conn;
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/* Find an unused local port. */
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again:
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++lastport;
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if(lastport >= 32000) {
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lastport = 4096;
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}
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for(c = 0; c < UIP_UDP_CONNS; ++c) {
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if(uip_udp_conns[c].lport == lastport) {
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goto again;
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}
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}
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conn = 0;
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for(c = 0; c < UIP_UDP_CONNS; ++c) {
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if(uip_udp_conns[c].lport == 0) {
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conn = &uip_udp_conns[c];
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break;
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}
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}
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if(conn == 0) {
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return 0;
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}
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conn->lport = HTONS(lastport);
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conn->rport = HTONS(rport);
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conn->ripaddr[0] = ripaddr[0];
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conn->ripaddr[1] = ripaddr[1];
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return conn;
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}
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#endif /* UIP_UDP */
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/*-----------------------------------------------------------------------------------*/
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void
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uip_unlisten(u16_t port)
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{
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for(c = 0; c < UIP_LISTENPORTS; ++c) {
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if(uip_listenports[c] == port) {
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uip_listenports[c] = 0;
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return;
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}
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}
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}
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/*-----------------------------------------------------------------------------------*/
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void
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uip_listen(u16_t port)
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{
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for(c = 0; c < UIP_LISTENPORTS; ++c) {
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if(uip_listenports[c] == 0) {
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uip_listenports[c] = port;
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return;
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}
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}
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}
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/*-----------------------------------------------------------------------------------*/
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/* XXX: IP fragment reassembly: not well-tested. */
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#if UIP_REASSEMBLY
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#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
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static u8_t uip_reassbuf[UIP_REASS_BUFSIZE];
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static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
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static const u8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f,
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0x0f, 0x07, 0x03, 0x01};
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static u16_t uip_reasslen;
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static u8_t uip_reassflags;
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#define UIP_REASS_FLAG_LASTFRAG 0x01
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static u8_t uip_reasstmr;
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#define IP_HLEN 20
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#define IP_MF 0x20
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static u8_t
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uip_reass(void)
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{
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u16_t offset, len;
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u16_t i;
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|
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/* If ip_reasstmr is zero, no packet is present in the buffer, so we
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write the IP header of the fragment into the reassembly
|
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buffer. The timer is updated with the maximum age. */
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if(uip_reasstmr == 0) {
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memcpy(uip_reassbuf, &BUF->vhl, IP_HLEN);
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uip_reasstmr = UIP_REASS_MAXAGE;
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uip_reassflags = 0;
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/* Clear the bitmap. */
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memset(uip_reassbitmap, sizeof(uip_reassbitmap), 0);
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}
|
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|
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/* Check if the incoming fragment matches the one currently present
|
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in the reasembly buffer. If so, we proceed with copying the
|
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fragment into the buffer. */
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if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] &&
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BUF->srcipaddr[1] == FBUF->srcipaddr[1] &&
|
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BUF->destipaddr[0] == FBUF->destipaddr[0] &&
|
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BUF->destipaddr[1] == FBUF->destipaddr[1] &&
|
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BUF->ipid[0] == FBUF->ipid[0] &&
|
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BUF->ipid[1] == FBUF->ipid[1]) {
|
|
|
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len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
|
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offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
|
|
|
|
/* If the offset or the offset + fragment length overflows the
|
|
reassembly buffer, we discard the entire packet. */
|
|
if(offset > UIP_REASS_BUFSIZE ||
|
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offset + len > UIP_REASS_BUFSIZE) {
|
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uip_reasstmr = 0;
|
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goto nullreturn;
|
|
}
|
|
|
|
/* Copy the fragment into the reassembly buffer, at the right
|
|
offset. */
|
|
memcpy(&uip_reassbuf[IP_HLEN + offset],
|
|
(char *)BUF + (int)((BUF->vhl & 0x0f) * 4),
|
|
len);
|
|
|
|
/* Update the bitmap. */
|
|
if(offset / (8 * 8) == (offset + len) / (8 * 8)) {
|
|
/* If the two endpoints are in the same byte, we only update
|
|
that byte. */
|
|
|
|
uip_reassbitmap[offset / (8 * 8)] |=
|
|
bitmap_bits[(offset / 8 ) & 7] &
|
|
~bitmap_bits[((offset + len) / 8 ) & 7];
|
|
} else {
|
|
/* If the two endpoints are in different bytes, we update the
|
|
bytes in the endpoints and fill the stuff inbetween with
|
|
0xff. */
|
|
uip_reassbitmap[offset / (8 * 8)] |=
|
|
bitmap_bits[(offset / 8 ) & 7];
|
|
for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
|
|
uip_reassbitmap[i] = 0xff;
|
|
}
|
|
uip_reassbitmap[(offset + len) / (8 * 8)] |=
|
|
~bitmap_bits[((offset + len) / 8 ) & 7];
|
|
}
|
|
|
|
/* If this fragment has the More Fragments flag set to zero, we
|
|
know that this is the last fragment, so we can calculate the
|
|
size of the entire packet. We also set the
|
|
IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
|
|
the final fragment. */
|
|
|
|
if((BUF->ipoffset[0] & IP_MF) == 0) {
|
|
uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
|
|
uip_reasslen = offset + len;
|
|
}
|
|
|
|
/* Finally, we check if we have a full packet in the buffer. We do
|
|
this by checking if we have the last fragment and if all bits
|
|
in the bitmap are set. */
|
|
if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) {
|
|
/* Check all bytes up to and including all but the last byte in
|
|
the bitmap. */
|
|
for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) {
|
|
if(uip_reassbitmap[i] != 0xff) {
|
|
goto nullreturn;
|
|
}
|
|
}
|
|
/* Check the last byte in the bitmap. It should contain just the
|
|
right amount of bits. */
|
|
if(uip_reassbitmap[uip_reasslen / (8 * 8)] !=
|
|
(u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) {
|
|
goto nullreturn;
|
|
}
|
|
|
|
/* If we have come this far, we have a full packet in the
|
|
buffer, so we allocate a pbuf and copy the packet into it. We
|
|
also reset the timer. */
|
|
uip_reasstmr = 0;
|
|
memcpy(BUF, FBUF, uip_reasslen);
|
|
|
|
/* Pretend to be a "normal" (i.e., not fragmented) IP packet
|
|
from now on. */
|
|
BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
|
|
BUF->len[0] = uip_reasslen >> 8;
|
|
BUF->len[1] = uip_reasslen & 0xff;
|
|
BUF->ipchksum = 0;
|
|
BUF->ipchksum = ~(uip_ipchksum());
|
|
|
|
return uip_reasslen;
|
|
}
|
|
}
|
|
|
|
nullreturn:
|
|
return 0;
|
|
}
|
|
#endif /* UIP_REASSEMBL */
|
|
/*-----------------------------------------------------------------------------------*/
|
|
static void
|
|
uip_add_rcv_nxt(u16_t n)
|
|
{
|
|
uip_add32(uip_conn->rcv_nxt, n);
|
|
uip_conn->rcv_nxt[0] = uip_acc32[0];
|
|
uip_conn->rcv_nxt[1] = uip_acc32[1];
|
|
uip_conn->rcv_nxt[2] = uip_acc32[2];
|
|
uip_conn->rcv_nxt[3] = uip_acc32[3];
|
|
}
|
|
/*-----------------------------------------------------------------------------------*/
|
|
void
|
|
uip_process(u8_t flag)
|
|
{
|
|
register struct uip_conn *uip_connr = uip_conn;
|
|
|
|
uip_appdata = &uip_buf[40 + UIP_LLH_LEN];
|
|
|
|
|
|
/* Check if we were invoked because of the perodic timer fireing. */
|
|
if(flag == UIP_TIMER) {
|
|
#if UIP_REASSEMBLY
|
|
if(uip_reasstmr != 0) {
|
|
--uip_reasstmr;
|
|
}
|
|
#endif /* UIP_REASSEMBLY */
|
|
/* Increase the initial sequence number. */
|
|
if(++iss[3] == 0) {
|
|
if(++iss[2] == 0) {
|
|
if(++iss[1] == 0) {
|
|
++iss[0];
|
|
}
|
|
}
|
|
}
|
|
uip_len = 0;
|
|
if(uip_connr->tcpstateflags == TIME_WAIT ||
|
|
uip_connr->tcpstateflags == FIN_WAIT_2) {
|
|
++(uip_connr->timer);
|
|
if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
|
|
uip_connr->tcpstateflags = CLOSED;
|
|
}
|
|
} else if(uip_connr->tcpstateflags != CLOSED) {
|
|
/* If the connection has outstanding data, we increase the
|
|
connection's timer and see if it has reached the RTO value
|
|
in which case we retransmit. */
|
|
if(uip_outstanding(uip_connr)) {
|
|
if(uip_connr->timer-- == 0) {
|
|
if(uip_connr->nrtx == UIP_MAXRTX ||
|
|
((uip_connr->tcpstateflags == SYN_SENT ||
|
|
uip_connr->tcpstateflags == SYN_RCVD) &&
|
|
uip_connr->nrtx == UIP_MAXSYNRTX)) {
|
|
uip_connr->tcpstateflags = CLOSED;
|
|
|
|
/* We call UIP_APPCALL() with uip_flags set to
|
|
UIP_TIMEDOUT to inform the application that the
|
|
connection has timed out. */
|
|
uip_flags = UIP_TIMEDOUT;
|
|
UIP_APPCALL();
|
|
|
|
/* We also send a reset packet to the remote host. */
|
|
BUF->flags = TCP_RST | TCP_ACK;
|
|
goto tcp_send_nodata;
|
|
}
|
|
|
|
/* Exponential backoff. */
|
|
uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4?
|
|
4:
|
|
uip_connr->nrtx);
|
|
++(uip_connr->nrtx);
|
|
|
|
/* Ok, so we need to retransmit. We do this differently
|
|
depending on which state we are in. In ESTABLISHED, we
|
|
call upon the application so that it may prepare the
|
|
data for the retransmit. In SYN_RCVD, we resend the
|
|
SYNACK that we sent earlier and in LAST_ACK we have to
|
|
retransmit our FINACK. */
|
|
UIP_STAT(++uip_stat.tcp.rexmit);
|
|
switch(uip_connr->tcpstateflags & TS_MASK) {
|
|
case SYN_RCVD:
|
|
/* In the SYN_RCVD state, we should retransmit our
|
|
SYNACK. */
|
|
goto tcp_send_synack;
|
|
|
|
#if UIP_ACTIVE_OPEN
|
|
case SYN_SENT:
|
|
/* In the SYN_SENT state, we retransmit out SYN. */
|
|
BUF->flags = 0;
|
|
goto tcp_send_syn;
|
|
#endif /* UIP_ACTIVE_OPEN */
|
|
|
|
case ESTABLISHED:
|
|
/* In the ESTABLISHED state, we call upon the application
|
|
to do the actual retransmit after which we jump into
|
|
the code for sending out the packet (the apprexmit
|
|
label). */
|
|
uip_len = 0;
|
|
uip_slen = 0;
|
|
uip_flags = UIP_REXMIT;
|
|
UIP_APPCALL();
|
|
goto apprexmit;
|
|
|
|
case FIN_WAIT_1:
|
|
case CLOSING:
|
|
case LAST_ACK:
|
|
/* In all these states we should retransmit a FINACK. */
|
|
goto tcp_send_finack;
|
|
|
|
}
|
|
}
|
|
} else if((uip_connr->tcpstateflags & TS_MASK) == ESTABLISHED) {
|
|
/* If there was no need for a retransmission, we poll the
|
|
application for new data. */
|
|
uip_len = 0;
|
|
uip_slen = 0;
|
|
uip_flags = UIP_POLL;
|
|
UIP_APPCALL();
|
|
goto appsend;
|
|
}
|
|
}
|
|
goto drop;
|
|
}
|
|
#if UIP_UDP
|
|
if(flag == UIP_UDP_TIMER) {
|
|
if(uip_udp_conn->lport != 0) {
|
|
uip_appdata = &uip_buf[UIP_LLH_LEN + 28];
|
|
uip_len = uip_slen = 0;
|
|
uip_flags = UIP_POLL;
|
|
UIP_UDP_APPCALL();
|
|
goto udp_send;
|
|
} else {
|
|
goto drop;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* This is where the input processing starts. */
|
|
UIP_STAT(++uip_stat.ip.recv);
|
|
|
|
|
|
/* Start of IPv4 input header processing code. */
|
|
|
|
/* Check validity of the IP header. */
|
|
if(BUF->vhl != 0x45) { /* IP version and header length. */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.vhlerr);
|
|
UIP_LOG("ip: invalid version or header length.");
|
|
goto drop;
|
|
}
|
|
|
|
/* Check the size of the packet. If the size reported to us in
|
|
uip_len doesn't match the size reported in the IP header, there
|
|
has been a transmission error and we drop the packet. */
|
|
|
|
if(BUF->len[0] != (uip_len >> 8)) { /* IP length, high byte. */
|
|
uip_len = (uip_len & 0xff) | (BUF->len[0] << 8);
|
|
}
|
|
if(BUF->len[1] != (uip_len & 0xff)) { /* IP length, low byte. */
|
|
uip_len = (uip_len & 0xff00) | BUF->len[1];
|
|
}
|
|
|
|
/* Check the fragment flag. */
|
|
if((BUF->ipoffset[0] & 0x3f) != 0 ||
|
|
BUF->ipoffset[1] != 0) {
|
|
#if UIP_REASSEMBLY
|
|
uip_len = uip_reass();
|
|
if(uip_len == 0) {
|
|
goto drop;
|
|
}
|
|
#else
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.fragerr);
|
|
UIP_LOG("ip: fragment dropped.");
|
|
goto drop;
|
|
#endif /* UIP_REASSEMBLY */
|
|
}
|
|
|
|
/* If we are configured to use ping IP address configuration and
|
|
hasn't been assigned an IP address yet, we accept all ICMP
|
|
packets. */
|
|
#if UIP_PINGADDRCONF
|
|
if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
|
|
if(BUF->proto == UIP_PROTO_ICMP) {
|
|
UIP_LOG("ip: possible ping config packet received.");
|
|
goto icmp_input;
|
|
} else {
|
|
UIP_LOG("ip: packet dropped since no address assigned.");
|
|
goto drop;
|
|
}
|
|
}
|
|
#endif /* UIP_PINGADDRCONF */
|
|
|
|
/* Check if the packet is destined for our IP address. */
|
|
if(BUF->destipaddr[0] != uip_hostaddr[0]) {
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_LOG("ip: packet not for us.");
|
|
goto drop;
|
|
}
|
|
if(BUF->destipaddr[1] != uip_hostaddr[1]) {
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_LOG("ip: packet not for us.");
|
|
goto drop;
|
|
}
|
|
|
|
#if 0
|
|
// IP checksum is wrong through Netgear DSL router
|
|
if (uip_ipchksum() != 0xffff) { /* Compute and check the IP header
|
|
checksum. */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.chkerr);
|
|
UIP_LOG("ip: bad checksum.");
|
|
goto drop;
|
|
}
|
|
#endif
|
|
|
|
if(BUF->proto == UIP_PROTO_TCP) /* Check for TCP packet. If so, jump
|
|
to the tcp_input label. */
|
|
goto tcp_input;
|
|
|
|
#if UIP_UDP
|
|
if(BUF->proto == UIP_PROTO_UDP)
|
|
goto udp_input;
|
|
#endif /* UIP_UDP */
|
|
|
|
if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from
|
|
here. */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.protoerr);
|
|
UIP_LOG("ip: neither tcp nor icmp.");
|
|
goto drop;
|
|
}
|
|
|
|
#if UIP_PINGADDRCONF
|
|
icmp_input:
|
|
#endif
|
|
UIP_STAT(++uip_stat.icmp.recv);
|
|
|
|
/* ICMP echo (i.e., ping) processing. This is simple, we only change
|
|
the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP
|
|
checksum before we return the packet. */
|
|
if(ICMPBUF->type != ICMP_ECHO) {
|
|
UIP_STAT(++uip_stat.icmp.drop);
|
|
UIP_STAT(++uip_stat.icmp.typeerr);
|
|
UIP_LOG("icmp: not icmp echo.");
|
|
goto drop;
|
|
}
|
|
|
|
/* If we are configured to use ping IP address assignment, we use
|
|
the destination IP address of this ping packet and assign it to
|
|
ourself. */
|
|
#if UIP_PINGADDRCONF
|
|
if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) {
|
|
uip_hostaddr[0] = BUF->destipaddr[0];
|
|
uip_hostaddr[1] = BUF->destipaddr[1];
|
|
}
|
|
#endif /* UIP_PINGADDRCONF */
|
|
|
|
ICMPBUF->type = ICMP_ECHO_REPLY;
|
|
|
|
if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) {
|
|
ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1;
|
|
} else {
|
|
ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8);
|
|
}
|
|
|
|
/* Swap IP addresses. */
|
|
tmp16 = BUF->destipaddr[0];
|
|
BUF->destipaddr[0] = BUF->srcipaddr[0];
|
|
BUF->srcipaddr[0] = tmp16;
|
|
tmp16 = BUF->destipaddr[1];
|
|
BUF->destipaddr[1] = BUF->srcipaddr[1];
|
|
BUF->srcipaddr[1] = tmp16;
|
|
|
|
UIP_STAT(++uip_stat.icmp.sent);
|
|
goto send;
|
|
|
|
/* End of IPv4 input header processing code. */
|
|
|
|
|
|
#if UIP_UDP
|
|
/* UDP input processing. */
|
|
udp_input:
|
|
/* UDP processing is really just a hack. We don't do anything to the
|
|
UDP/IP headers, but let the UDP application do all the hard
|
|
work. If the application sets uip_slen, it has a packet to
|
|
send. */
|
|
#if UIP_UDP_CHECKSUMS
|
|
if(uip_udpchksum() != 0xffff) {
|
|
UIP_STAT(++uip_stat.udp.drop);
|
|
UIP_STAT(++uip_stat.udp.chkerr);
|
|
UIP_LOG("udp: bad checksum.");
|
|
goto drop;
|
|
}
|
|
#endif /* UIP_UDP_CHECKSUMS */
|
|
|
|
/* Demultiplex this UDP packet between the UDP "connections". */
|
|
for(uip_udp_conn = &uip_udp_conns[0];
|
|
uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS];
|
|
++uip_udp_conn) {
|
|
if(uip_udp_conn->lport != 0 &&
|
|
UDPBUF->destport == uip_udp_conn->lport &&
|
|
(uip_udp_conn->rport == 0 ||
|
|
UDPBUF->srcport == uip_udp_conn->rport) &&
|
|
BUF->srcipaddr[0] == uip_udp_conn->ripaddr[0] &&
|
|
BUF->srcipaddr[1] == uip_udp_conn->ripaddr[1]) {
|
|
goto udp_found;
|
|
}
|
|
}
|
|
goto drop;
|
|
|
|
udp_found:
|
|
uip_len = uip_len - 28;
|
|
uip_appdata = &uip_buf[UIP_LLH_LEN + 28];
|
|
uip_flags = UIP_NEWDATA;
|
|
uip_slen = 0;
|
|
UIP_UDP_APPCALL();
|
|
udp_send:
|
|
if(uip_slen == 0) {
|
|
goto drop;
|
|
}
|
|
uip_len = uip_slen + 28;
|
|
|
|
BUF->len[0] = (uip_len >> 8);
|
|
BUF->len[1] = (uip_len & 0xff);
|
|
|
|
BUF->proto = UIP_PROTO_UDP;
|
|
|
|
UDPBUF->udplen = HTONS(uip_slen + 8);
|
|
UDPBUF->udpchksum = 0;
|
|
#if UIP_UDP_CHECKSUMS
|
|
/* Calculate UDP checksum. */
|
|
UDPBUF->udpchksum = ~(uip_udpchksum());
|
|
if(UDPBUF->udpchksum == 0) {
|
|
UDPBUF->udpchksum = 0xffff;
|
|
}
|
|
#endif /* UIP_UDP_CHECKSUMS */
|
|
|
|
BUF->srcport = uip_udp_conn->lport;
|
|
BUF->destport = uip_udp_conn->rport;
|
|
|
|
BUF->srcipaddr[0] = uip_hostaddr[0];
|
|
BUF->srcipaddr[1] = uip_hostaddr[1];
|
|
BUF->destipaddr[0] = uip_udp_conn->ripaddr[0];
|
|
BUF->destipaddr[1] = uip_udp_conn->ripaddr[1];
|
|
|
|
uip_appdata = &uip_buf[UIP_LLH_LEN + 40];
|
|
goto ip_send_nolen;
|
|
#endif /* UIP_UDP */
|
|
|
|
/* TCP input processing. */
|
|
tcp_input:
|
|
UIP_STAT(++uip_stat.tcp.recv);
|
|
|
|
/* Start of TCP input header processing code. */
|
|
|
|
#if 1 // FIXME
|
|
if(uip_tcpchksum() != 0xffff) { /* Compute and check the TCP
|
|
checksum. */
|
|
UIP_STAT(++uip_stat.tcp.drop);
|
|
UIP_STAT(++uip_stat.tcp.chkerr);
|
|
UIP_LOG("tcp: bad checksum.");
|
|
goto drop;
|
|
}
|
|
#endif
|
|
|
|
/* Demultiplex this segment. */
|
|
/* First check any active connections. */
|
|
for(uip_connr = &uip_conns[0]; uip_connr < &uip_conns[UIP_CONNS]; ++uip_connr) {
|
|
if(uip_connr->tcpstateflags != CLOSED &&
|
|
BUF->destport == uip_connr->lport &&
|
|
BUF->srcport == uip_connr->rport &&
|
|
BUF->srcipaddr[0] == uip_connr->ripaddr[0] &&
|
|
BUF->srcipaddr[1] == uip_connr->ripaddr[1]) {
|
|
goto found;
|
|
}
|
|
}
|
|
|
|
/* If we didn't find and active connection that expected the packet,
|
|
either this packet is an old duplicate, or this is a SYN packet
|
|
destined for a connection in LISTEN. If the SYN flag isn't set,
|
|
it is an old packet and we send a RST. */
|
|
if((BUF->flags & TCP_CTL) != TCP_SYN)
|
|
goto reset;
|
|
|
|
tmp16 = BUF->destport;
|
|
/* Next, check listening connections. */
|
|
for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
|
if(tmp16 == uip_listenports[c])
|
|
goto found_listen;
|
|
}
|
|
|
|
/* No matching connection found, so we send a RST packet. */
|
|
UIP_STAT(++uip_stat.tcp.synrst);
|
|
reset:
|
|
|
|
/* We do not send resets in response to resets. */
|
|
if(BUF->flags & TCP_RST)
|
|
goto drop;
|
|
|
|
UIP_STAT(++uip_stat.tcp.rst);
|
|
|
|
BUF->flags = TCP_RST | TCP_ACK;
|
|
uip_len = 40;
|
|
BUF->tcpoffset = 5 << 4;
|
|
|
|
/* Flip the seqno and ackno fields in the TCP header. */
|
|
c = BUF->seqno[3];
|
|
BUF->seqno[3] = BUF->ackno[3];
|
|
BUF->ackno[3] = c;
|
|
|
|
c = BUF->seqno[2];
|
|
BUF->seqno[2] = BUF->ackno[2];
|
|
BUF->ackno[2] = c;
|
|
|
|
c = BUF->seqno[1];
|
|
BUF->seqno[1] = BUF->ackno[1];
|
|
BUF->ackno[1] = c;
|
|
|
|
c = BUF->seqno[0];
|
|
BUF->seqno[0] = BUF->ackno[0];
|
|
BUF->ackno[0] = c;
|
|
|
|
/* We also have to increase the sequence number we are
|
|
acknowledging. If the least significant byte overflowed, we need
|
|
to propagate the carry to the other bytes as well. */
|
|
if(++BUF->ackno[3] == 0) {
|
|
if(++BUF->ackno[2] == 0) {
|
|
if(++BUF->ackno[1] == 0) {
|
|
++BUF->ackno[0];
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Swap port numbers. */
|
|
tmp16 = BUF->srcport;
|
|
BUF->srcport = BUF->destport;
|
|
BUF->destport = tmp16;
|
|
|
|
/* Swap IP addresses. */
|
|
tmp16 = BUF->destipaddr[0];
|
|
BUF->destipaddr[0] = BUF->srcipaddr[0];
|
|
BUF->srcipaddr[0] = tmp16;
|
|
tmp16 = BUF->destipaddr[1];
|
|
BUF->destipaddr[1] = BUF->srcipaddr[1];
|
|
BUF->srcipaddr[1] = tmp16;
|
|
|
|
|
|
/* And send out the RST packet! */
|
|
goto tcp_send_noconn;
|
|
|
|
/* This label will be jumped to if we matched the incoming packet
|
|
with a connection in LISTEN. In that case, we should create a new
|
|
connection and send a SYNACK in return. */
|
|
found_listen:
|
|
/* First we check if there are any connections avaliable. Unused
|
|
connections are kept in the same table as used connections, but
|
|
unused ones have the tcpstate set to CLOSED. Also, connections in
|
|
TIME_WAIT are kept track of and we'll use the oldest one if no
|
|
CLOSED connections are found. Thanks to Eddie C. Dost for a very
|
|
nice algorithm for the TIME_WAIT search. */
|
|
uip_connr = 0;
|
|
for(c = 0; c < UIP_CONNS; ++c) {
|
|
if(uip_conns[c].tcpstateflags == CLOSED) {
|
|
uip_connr = &uip_conns[c];
|
|
break;
|
|
}
|
|
if(uip_conns[c].tcpstateflags == TIME_WAIT) {
|
|
if(uip_connr == 0 ||
|
|
uip_conns[c].timer > uip_connr->timer) {
|
|
uip_connr = &uip_conns[c];
|
|
}
|
|
}
|
|
}
|
|
|
|
if(uip_connr == 0) {
|
|
/* All connections are used already, we drop packet and hope that
|
|
the remote end will retransmit the packet at a time when we
|
|
have more spare connections. */
|
|
UIP_STAT(++uip_stat.tcp.syndrop);
|
|
UIP_LOG("tcp: found no unused connections.");
|
|
goto drop;
|
|
}
|
|
uip_conn = uip_connr;
|
|
|
|
/* Fill in the necessary fields for the new connection. */
|
|
uip_connr->rto = uip_connr->timer = UIP_RTO;
|
|
uip_connr->sa = 0;
|
|
uip_connr->sv = 4;
|
|
uip_connr->nrtx = 0;
|
|
uip_connr->lport = BUF->destport;
|
|
uip_connr->rport = BUF->srcport;
|
|
uip_connr->ripaddr[0] = BUF->srcipaddr[0];
|
|
uip_connr->ripaddr[1] = BUF->srcipaddr[1];
|
|
uip_connr->tcpstateflags = SYN_RCVD;
|
|
|
|
uip_connr->snd_nxt[0] = iss[0];
|
|
uip_connr->snd_nxt[1] = iss[1];
|
|
uip_connr->snd_nxt[2] = iss[2];
|
|
uip_connr->snd_nxt[3] = iss[3];
|
|
uip_connr->len = 1;
|
|
|
|
/* rcv_nxt should be the seqno from the incoming packet + 1. */
|
|
uip_connr->rcv_nxt[3] = BUF->seqno[3];
|
|
uip_connr->rcv_nxt[2] = BUF->seqno[2];
|
|
uip_connr->rcv_nxt[1] = BUF->seqno[1];
|
|
uip_connr->rcv_nxt[0] = BUF->seqno[0];
|
|
uip_add_rcv_nxt(1);
|
|
|
|
/* Parse the TCP MSS option, if present. */
|
|
if((BUF->tcpoffset & 0xf0) > 0x50) {
|
|
for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
|
|
opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c];
|
|
if(opt == 0x00) {
|
|
/* End of options. */
|
|
break;
|
|
} else if(opt == 0x01) {
|
|
++c;
|
|
/* NOP option. */
|
|
} else if(opt == 0x02 &&
|
|
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) {
|
|
/* An MSS option with the right option length. */
|
|
tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
|
|
(u16_t)uip_buf[40 + UIP_LLH_LEN + 3 + c];
|
|
uip_connr->initialmss = uip_connr->mss =
|
|
tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
|
|
|
|
/* And we are done processing options. */
|
|
break;
|
|
} else {
|
|
/* All other options have a length field, so that we easily
|
|
can skip past them. */
|
|
if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
|
|
/* If the length field is zero, the options are malformed
|
|
and we don't process them further. */
|
|
break;
|
|
}
|
|
c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Our response will be a SYNACK. */
|
|
#if UIP_ACTIVE_OPEN
|
|
tcp_send_synack:
|
|
BUF->flags = TCP_ACK;
|
|
|
|
tcp_send_syn:
|
|
BUF->flags |= TCP_SYN;
|
|
#else /* UIP_ACTIVE_OPEN */
|
|
tcp_send_synack:
|
|
BUF->flags = TCP_SYN | TCP_ACK;
|
|
#endif /* UIP_ACTIVE_OPEN */
|
|
|
|
/* We send out the TCP Maximum Segment Size option with our
|
|
SYNACK. */
|
|
BUF->optdata[0] = 2;
|
|
BUF->optdata[1] = 4;
|
|
BUF->optdata[2] = (UIP_TCP_MSS) / 256;
|
|
BUF->optdata[3] = (UIP_TCP_MSS) & 255;
|
|
uip_len = 44;
|
|
BUF->tcpoffset = 6 << 4;
|
|
goto tcp_send;
|
|
|
|
/* This label will be jumped to if we found an active connection. */
|
|
found:
|
|
uip_conn = uip_connr;
|
|
uip_flags = 0;
|
|
|
|
/* We do a very naive form of TCP reset processing; we just accept
|
|
any RST and kill our connection. We should in fact check if the
|
|
sequence number of this reset is wihtin our advertised window
|
|
before we accept the reset. */
|
|
if(BUF->flags & TCP_RST) {
|
|
uip_connr->tcpstateflags = CLOSED;
|
|
UIP_LOG("tcp: got reset, aborting connection.");
|
|
uip_flags = UIP_ABORT;
|
|
UIP_APPCALL();
|
|
goto drop;
|
|
}
|
|
/* Calculated the length of the data, if the application has sent
|
|
any data to us. */
|
|
c = (BUF->tcpoffset >> 4) << 2;
|
|
/* uip_len will contain the length of the actual TCP data. This is
|
|
calculated by subtracing the length of the TCP header (in
|
|
c) and the length of the IP header (20 bytes). */
|
|
uip_len = uip_len - c - 20;
|
|
|
|
/* First, check if the sequence number of the incoming packet is
|
|
what we're expecting next. If not, we send out an ACK with the
|
|
correct numbers in. */
|
|
if(uip_len > 0 &&
|
|
(BUF->seqno[0] != uip_connr->rcv_nxt[0] ||
|
|
BUF->seqno[1] != uip_connr->rcv_nxt[1] ||
|
|
BUF->seqno[2] != uip_connr->rcv_nxt[2] ||
|
|
BUF->seqno[3] != uip_connr->rcv_nxt[3])) {
|
|
goto tcp_send_ack;
|
|
}
|
|
|
|
/* Next, check if the incoming segment acknowledges any outstanding
|
|
data. If so, we update the sequence number, reset the length of
|
|
the outstanding data, calculate RTT estimations, and reset the
|
|
retransmission timer. */
|
|
if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) {
|
|
uip_add32(uip_connr->snd_nxt, uip_connr->len);
|
|
if(BUF->ackno[0] == uip_acc32[0] &&
|
|
BUF->ackno[1] == uip_acc32[1] &&
|
|
BUF->ackno[2] == uip_acc32[2] &&
|
|
BUF->ackno[3] == uip_acc32[3]) {
|
|
/* Update sequence number. */
|
|
uip_connr->snd_nxt[0] = uip_acc32[0];
|
|
uip_connr->snd_nxt[1] = uip_acc32[1];
|
|
uip_connr->snd_nxt[2] = uip_acc32[2];
|
|
uip_connr->snd_nxt[3] = uip_acc32[3];
|
|
|
|
|
|
/* Do RTT estimation, unless we have done retransmissions. */
|
|
if(uip_connr->nrtx == 0) {
|
|
signed char m;
|
|
m = uip_connr->rto - uip_connr->timer;
|
|
/* This is taken directly from VJs original code in his paper */
|
|
m = m - (uip_connr->sa >> 3);
|
|
uip_connr->sa += m;
|
|
if(m < 0) {
|
|
m = -m;
|
|
}
|
|
m = m - (uip_connr->sv >> 2);
|
|
uip_connr->sv += m;
|
|
uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv;
|
|
|
|
}
|
|
/* Set the acknowledged flag. */
|
|
uip_flags = UIP_ACKDATA;
|
|
/* Reset the retransmission timer. */
|
|
uip_connr->timer = uip_connr->rto;
|
|
}
|
|
|
|
}
|
|
|
|
/* Do different things depending on in what state the connection is. */
|
|
switch(uip_connr->tcpstateflags & TS_MASK) {
|
|
/* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
|
|
implemented, since we force the application to close when the
|
|
peer sends a FIN (hence the application goes directly from
|
|
ESTABLISHED to LAST_ACK). */
|
|
case SYN_RCVD:
|
|
/* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
|
|
we are waiting for an ACK that acknowledges the data we sent
|
|
out the last time. Therefore, we want to have the UIP_ACKDATA
|
|
flag set. If so, we enter the ESTABLISHED state. */
|
|
if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = ESTABLISHED;
|
|
uip_flags = UIP_CONNECTED;
|
|
uip_connr->len = 0;
|
|
if(uip_len > 0) {
|
|
uip_flags |= UIP_NEWDATA;
|
|
uip_add_rcv_nxt(uip_len);
|
|
}
|
|
uip_slen = 0;
|
|
UIP_APPCALL();
|
|
goto appsend;
|
|
}
|
|
goto drop;
|
|
#if UIP_ACTIVE_OPEN
|
|
case SYN_SENT:
|
|
/* In SYN_SENT, we wait for a SYNACK that is sent in response to
|
|
our SYN. The rcv_nxt is set to sequence number in the SYNACK
|
|
plus one, and we send an ACK. We move into the ESTABLISHED
|
|
state. */
|
|
if((uip_flags & UIP_ACKDATA) &&
|
|
BUF->flags == (TCP_SYN | TCP_ACK)) {
|
|
|
|
/* Parse the TCP MSS option, if present. */
|
|
if((BUF->tcpoffset & 0xf0) > 0x50) {
|
|
for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
|
|
opt = uip_buf[40 + UIP_LLH_LEN + c];
|
|
if(opt == 0x00) {
|
|
/* End of options. */
|
|
break;
|
|
} else if(opt == 0x01) {
|
|
++c;
|
|
/* NOP option. */
|
|
} else if(opt == 0x02 &&
|
|
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) {
|
|
/* An MSS option with the right option length. */
|
|
tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
|
|
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c];
|
|
uip_connr->initialmss =
|
|
uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
|
|
|
|
/* And we are done processing options. */
|
|
break;
|
|
} else {
|
|
/* All other options have a length field, so that we easily
|
|
can skip past them. */
|
|
if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
|
|
/* If the length field is zero, the options are malformed
|
|
and we don't process them further. */
|
|
break;
|
|
}
|
|
c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
|
|
}
|
|
}
|
|
}
|
|
uip_connr->tcpstateflags = ESTABLISHED;
|
|
uip_connr->rcv_nxt[0] = BUF->seqno[0];
|
|
uip_connr->rcv_nxt[1] = BUF->seqno[1];
|
|
uip_connr->rcv_nxt[2] = BUF->seqno[2];
|
|
uip_connr->rcv_nxt[3] = BUF->seqno[3];
|
|
uip_add_rcv_nxt(1);
|
|
uip_flags = UIP_CONNECTED | UIP_NEWDATA;
|
|
uip_connr->len = 0;
|
|
uip_len = 0;
|
|
uip_slen = 0;
|
|
UIP_APPCALL();
|
|
goto appsend;
|
|
}
|
|
goto reset;
|
|
#endif /* UIP_ACTIVE_OPEN */
|
|
|
|
case ESTABLISHED:
|
|
/* In the ESTABLISHED state, we call upon the application to feed
|
|
data into the uip_buf. If the UIP_ACKDATA flag is set, the
|
|
application should put new data into the buffer, otherwise we are
|
|
retransmitting an old segment, and the application should put that
|
|
data into the buffer.
|
|
|
|
If the incoming packet is a FIN, we should close the connection on
|
|
this side as well, and we send out a FIN and enter the LAST_ACK
|
|
state. We require that there is no outstanding data; otherwise the
|
|
sequence numbers will be screwed up. */
|
|
|
|
if(BUF->flags & TCP_FIN) {
|
|
if(uip_outstanding(uip_connr)) {
|
|
goto drop;
|
|
}
|
|
uip_add_rcv_nxt(1 + uip_len);
|
|
uip_flags = UIP_CLOSE;
|
|
if(uip_len > 0) {
|
|
uip_flags |= UIP_NEWDATA;
|
|
}
|
|
UIP_APPCALL();
|
|
uip_connr->len = 1;
|
|
uip_connr->tcpstateflags = LAST_ACK;
|
|
uip_connr->nrtx = 0;
|
|
tcp_send_finack:
|
|
BUF->flags = TCP_FIN | TCP_ACK;
|
|
goto tcp_send_nodata;
|
|
}
|
|
|
|
/* Check the URG flag. If this is set, the segment carries urgent
|
|
data that we must pass to the application. */
|
|
if(BUF->flags & TCP_URG) {
|
|
#if UIP_URGDATA > 0
|
|
uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1];
|
|
if(uip_urglen > uip_len) {
|
|
/* There is more urgent data in the next segment to come. */
|
|
uip_urglen = uip_len;
|
|
}
|
|
uip_add_rcv_nxt(uip_urglen);
|
|
uip_len -= uip_urglen;
|
|
uip_urgdata = uip_appdata;
|
|
uip_appdata += uip_urglen;
|
|
} else {
|
|
uip_urglen = 0;
|
|
#endif /* UIP_URGDATA > 0 */
|
|
uip_appdata += (BUF->urgp[0] << 8) | BUF->urgp[1];
|
|
uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
|
|
}
|
|
|
|
|
|
/* If uip_len > 0 we have TCP data in the packet, and we flag this
|
|
by setting the UIP_NEWDATA flag and update the sequence number
|
|
we acknowledge. If the application has stopped the dataflow
|
|
using uip_stop(), we must not accept any data packets from the
|
|
remote host. */
|
|
if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
|
|
uip_flags |= UIP_NEWDATA;
|
|
uip_add_rcv_nxt(uip_len);
|
|
}
|
|
|
|
/* Check if the available buffer space advertised by the other end
|
|
is smaller than the initial MSS for this connection. If so, we
|
|
set the current MSS to the window size to ensure that the
|
|
application does not send more data than the other end can
|
|
handle.
|
|
|
|
If the remote host advertises a zero window, we set the MSS to
|
|
the initial MSS so that the application will send an entire MSS
|
|
of data. This data will not be acknowledged by the receiver,
|
|
and the application will retransmit it. This is called the
|
|
"persistent timer" and uses the retransmission mechanim.
|
|
*/
|
|
tmp16 = ((u16_t)BUF->wnd[0] << 8) + (u16_t)BUF->wnd[1];
|
|
if(tmp16 > uip_connr->initialmss ||
|
|
tmp16 == 0) {
|
|
tmp16 = uip_connr->initialmss;
|
|
}
|
|
uip_connr->mss = tmp16;
|
|
|
|
/* If this packet constitutes an ACK for outstanding data (flagged
|
|
by the UIP_ACKDATA flag, we should call the application since it
|
|
might want to send more data. If the incoming packet had data
|
|
from the peer (as flagged by the UIP_NEWDATA flag), the
|
|
application must also be notified.
|
|
|
|
When the application is called, the global variable uip_len
|
|
contains the length of the incoming data. The application can
|
|
access the incoming data through the global pointer
|
|
uip_appdata, which usually points 40 bytes into the uip_buf
|
|
array.
|
|
|
|
If the application wishes to send any data, this data should be
|
|
put into the uip_appdata and the length of the data should be
|
|
put into uip_len. If the application don't have any data to
|
|
send, uip_len must be set to 0. */
|
|
if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) {
|
|
uip_slen = 0;
|
|
UIP_APPCALL();
|
|
|
|
appsend:
|
|
|
|
if(uip_flags & UIP_ABORT) {
|
|
uip_slen = 0;
|
|
uip_connr->tcpstateflags = CLOSED;
|
|
BUF->flags = TCP_RST | TCP_ACK;
|
|
goto tcp_send_nodata;
|
|
}
|
|
|
|
if(uip_flags & UIP_CLOSE) {
|
|
uip_slen = 0;
|
|
uip_connr->len = 1;
|
|
uip_connr->tcpstateflags = FIN_WAIT_1;
|
|
uip_connr->nrtx = 0;
|
|
BUF->flags = TCP_FIN | TCP_ACK;
|
|
goto tcp_send_nodata;
|
|
}
|
|
|
|
/* If uip_slen > 0, the application has data to be sent. */
|
|
if(uip_slen > 0) {
|
|
|
|
/* If the connection has acknowledged data, the contents of
|
|
the ->len variable should be discarded. */
|
|
if((uip_flags & UIP_ACKDATA) != 0) {
|
|
uip_connr->len = 0;
|
|
}
|
|
|
|
/* If the ->len variable is non-zero the connection has
|
|
already data in transit and cannot send anymore right
|
|
now. */
|
|
if(uip_connr->len == 0) {
|
|
|
|
/* The application cannot send more than what is allowed by
|
|
the mss (the minumum of the MSS and the available
|
|
window). */
|
|
if(uip_slen > uip_connr->mss) {
|
|
uip_slen = uip_connr->mss;
|
|
}
|
|
|
|
/* Remember how much data we send out now so that we know
|
|
when everything has been acknowledged. */
|
|
uip_connr->len = uip_slen;
|
|
} else {
|
|
|
|
/* If the application already had unacknowledged data, we
|
|
make sure that the application does not send (i.e.,
|
|
retransmit) out more than it previously sent out. */
|
|
uip_slen = uip_connr->len;
|
|
}
|
|
} else {
|
|
uip_connr->len = 0;
|
|
}
|
|
uip_connr->nrtx = 0;
|
|
apprexmit:
|
|
uip_appdata = uip_sappdata;
|
|
|
|
/* If the application has data to be sent, or if the incoming
|
|
packet had new data in it, we must send out a packet. */
|
|
if(uip_slen > 0 && uip_connr->len > 0) {
|
|
/* Add the length of the IP and TCP headers. */
|
|
uip_len = uip_connr->len + UIP_TCPIP_HLEN;
|
|
/* We always set the ACK flag in response packets. */
|
|
BUF->flags = TCP_ACK | TCP_PSH;
|
|
/* Send the packet. */
|
|
goto tcp_send_noopts;
|
|
}
|
|
/* If there is no data to send, just send out a pure ACK if
|
|
there is newdata. */
|
|
if(uip_flags & UIP_NEWDATA) {
|
|
uip_len = UIP_TCPIP_HLEN;
|
|
BUF->flags = TCP_ACK;
|
|
goto tcp_send_noopts;
|
|
}
|
|
}
|
|
goto drop;
|
|
case LAST_ACK:
|
|
/* We can close this connection if the peer has acknowledged our
|
|
FIN. This is indicated by the UIP_ACKDATA flag. */
|
|
if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = CLOSED;
|
|
uip_flags = UIP_CLOSE;
|
|
UIP_APPCALL();
|
|
}
|
|
break;
|
|
|
|
case FIN_WAIT_1:
|
|
/* The application has closed the connection, but the remote host
|
|
hasn't closed its end yet. Thus we do nothing but wait for a
|
|
FIN from the other side. */
|
|
if(uip_len > 0) {
|
|
uip_add_rcv_nxt(uip_len);
|
|
}
|
|
if(BUF->flags & TCP_FIN) {
|
|
if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = TIME_WAIT;
|
|
uip_connr->timer = 0;
|
|
uip_connr->len = 0;
|
|
} else {
|
|
uip_connr->tcpstateflags = CLOSING;
|
|
}
|
|
uip_add_rcv_nxt(1);
|
|
uip_flags = UIP_CLOSE;
|
|
UIP_APPCALL();
|
|
goto tcp_send_ack;
|
|
} else if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = FIN_WAIT_2;
|
|
uip_connr->len = 0;
|
|
goto drop;
|
|
}
|
|
if(uip_len > 0) {
|
|
goto tcp_send_ack;
|
|
}
|
|
goto drop;
|
|
|
|
case FIN_WAIT_2:
|
|
if(uip_len > 0) {
|
|
uip_add_rcv_nxt(uip_len);
|
|
}
|
|
if(BUF->flags & TCP_FIN) {
|
|
uip_connr->tcpstateflags = TIME_WAIT;
|
|
uip_connr->timer = 0;
|
|
uip_add_rcv_nxt(1);
|
|
uip_flags = UIP_CLOSE;
|
|
UIP_APPCALL();
|
|
goto tcp_send_ack;
|
|
}
|
|
if(uip_len > 0) {
|
|
goto tcp_send_ack;
|
|
}
|
|
goto drop;
|
|
|
|
case TIME_WAIT:
|
|
goto tcp_send_ack;
|
|
|
|
case CLOSING:
|
|
if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = TIME_WAIT;
|
|
uip_connr->timer = 0;
|
|
}
|
|
}
|
|
goto drop;
|
|
|
|
|
|
/* We jump here when we are ready to send the packet, and just want
|
|
to set the appropriate TCP sequence numbers in the TCP header. */
|
|
tcp_send_ack:
|
|
BUF->flags = TCP_ACK;
|
|
tcp_send_nodata:
|
|
uip_len = 40;
|
|
tcp_send_noopts:
|
|
BUF->tcpoffset = 5 << 4;
|
|
tcp_send:
|
|
/* We're done with the input processing. We are now ready to send a
|
|
reply. Our job is to fill in all the fields of the TCP and IP
|
|
headers before calculating the checksum and finally send the
|
|
packet. */
|
|
BUF->ackno[0] = uip_connr->rcv_nxt[0];
|
|
BUF->ackno[1] = uip_connr->rcv_nxt[1];
|
|
BUF->ackno[2] = uip_connr->rcv_nxt[2];
|
|
BUF->ackno[3] = uip_connr->rcv_nxt[3];
|
|
|
|
BUF->seqno[0] = uip_connr->snd_nxt[0];
|
|
BUF->seqno[1] = uip_connr->snd_nxt[1];
|
|
BUF->seqno[2] = uip_connr->snd_nxt[2];
|
|
BUF->seqno[3] = uip_connr->snd_nxt[3];
|
|
|
|
BUF->proto = UIP_PROTO_TCP;
|
|
|
|
BUF->srcport = uip_connr->lport;
|
|
BUF->destport = uip_connr->rport;
|
|
|
|
BUF->srcipaddr[0] = uip_hostaddr[0];
|
|
BUF->srcipaddr[1] = uip_hostaddr[1];
|
|
BUF->destipaddr[0] = uip_connr->ripaddr[0];
|
|
BUF->destipaddr[1] = uip_connr->ripaddr[1];
|
|
|
|
|
|
if(uip_connr->tcpstateflags & UIP_STOPPED) {
|
|
/* If the connection has issued uip_stop(), we advertise a zero
|
|
window so that the remote host will stop sending data. */
|
|
BUF->wnd[0] = BUF->wnd[1] = 0;
|
|
} else {
|
|
BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
|
|
BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff);
|
|
}
|
|
|
|
tcp_send_noconn:
|
|
|
|
BUF->len[0] = (uip_len >> 8);
|
|
BUF->len[1] = (uip_len & 0xff);
|
|
|
|
/* Calculate TCP checksum. */
|
|
BUF->tcpchksum = 0;
|
|
BUF->tcpchksum = ~(uip_tcpchksum());
|
|
|
|
|
|
#if UIP_UDP
|
|
ip_send_nolen:
|
|
#endif
|
|
|
|
BUF->vhl = 0x45;
|
|
BUF->tos = 0;
|
|
BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
|
|
BUF->ttl = UIP_TTL;
|
|
++ipid;
|
|
BUF->ipid[0] = ipid >> 8;
|
|
BUF->ipid[1] = ipid & 0xff;
|
|
|
|
/* Calculate IP checksum. */
|
|
BUF->ipchksum = 0;
|
|
BUF->ipchksum = ~(uip_ipchksum());
|
|
|
|
UIP_STAT(++uip_stat.tcp.sent);
|
|
send:
|
|
UIP_STAT(++uip_stat.ip.sent);
|
|
/* Return and let the caller do the actual transmission. */
|
|
return;
|
|
drop:
|
|
uip_len = 0;
|
|
return;
|
|
}
|
|
/*-----------------------------------------------------------------------------------*/
|
|
u16_t
|
|
htons(u16_t val)
|
|
{
|
|
return HTONS(val);
|
|
}
|
|
/*-----------------------------------------------------------------------------------*/
|
|
/** @} */
|