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povik |
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/** |
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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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#include "string.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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u8_t uip_urglen, uip_surglen; |
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#endif /* UIP_URGDATA > 0 */ |
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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 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 * 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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347 |
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#define IP_HLEN 20 |
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#define IP_MF 0x20 |
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350 |
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static u8_t |
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uip_reass(void) |
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353 |
{ |
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u16_t offset, len; |
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355 |
u16_t i; |
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356 |
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357 |
/* If ip_reasstmr is zero, no packet is present in the buffer, so we |
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358 |
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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360 |
if(uip_reasstmr == 0) { |
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361 |
memcpy(uip_reassbuf, &BUF->vhl, IP_HLEN); |
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362 |
uip_reasstmr = UIP_REASS_MAXAGE; |
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363 |
uip_reassflags = 0; |
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364 |
/* Clear the bitmap. */ |
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365 |
memset(uip_reassbitmap, sizeof(uip_reassbitmap), 0); |
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366 |
} |
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367 |
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368 |
/* Check if the incoming fragment matches the one currently present |
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369 |
in the reasembly buffer. If so, we proceed with copying the |
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370 |
fragment into the buffer. */ |
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371 |
if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] && |
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372 |
BUF->srcipaddr[1] == FBUF->srcipaddr[1] && |
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373 |
BUF->destipaddr[0] == FBUF->destipaddr[0] && |
|
|
374 |
BUF->destipaddr[1] == FBUF->destipaddr[1] && |
|
|
375 |
BUF->ipid[0] == FBUF->ipid[0] && |
|
|
376 |
BUF->ipid[1] == FBUF->ipid[1]) { |
|
|
377 |
|
|
|
378 |
len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4; |
|
|
379 |
offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8; |
|
|
380 |
|
|
|
381 |
/* If the offset or the offset + fragment length overflows the |
|
|
382 |
reassembly buffer, we discard the entire packet. */ |
|
|
383 |
if(offset > UIP_REASS_BUFSIZE || |
|
|
384 |
offset + len > UIP_REASS_BUFSIZE) { |
|
|
385 |
uip_reasstmr = 0; |
|
|
386 |
goto nullreturn; |
|
|
387 |
} |
|
|
388 |
|
|
|
389 |
/* Copy the fragment into the reassembly buffer, at the right |
|
|
390 |
offset. */ |
|
|
391 |
memcpy(&uip_reassbuf[IP_HLEN + offset], |
|
|
392 |
(char *)BUF + (int)((BUF->vhl & 0x0f) * 4), |
|
|
393 |
len); |
|
|
394 |
|
|
|
395 |
/* Update the bitmap. */ |
|
|
396 |
if(offset / (8 * 8) == (offset + len) / (8 * 8)) { |
|
|
397 |
/* If the two endpoints are in the same byte, we only update |
|
|
398 |
that byte. */ |
|
|
399 |
|
|
|
400 |
uip_reassbitmap[offset / (8 * 8)] |= |
|
|
401 |
bitmap_bits[(offset / 8 ) & 7] & |
|
|
402 |
~bitmap_bits[((offset + len) / 8 ) & 7]; |
|
|
403 |
} else { |
|
|
404 |
/* If the two endpoints are in different bytes, we update the |
|
|
405 |
bytes in the endpoints and fill the stuff inbetween with |
|
|
406 |
0xff. */ |
|
|
407 |
uip_reassbitmap[offset / (8 * 8)] |= |
|
|
408 |
bitmap_bits[(offset / 8 ) & 7]; |
|
|
409 |
for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) { |
|
|
410 |
uip_reassbitmap[i] = 0xff; |
|
|
411 |
} |
|
|
412 |
uip_reassbitmap[(offset + len) / (8 * 8)] |= |
|
|
413 |
~bitmap_bits[((offset + len) / 8 ) & 7]; |
|
|
414 |
} |
|
|
415 |
|
|
|
416 |
/* If this fragment has the More Fragments flag set to zero, we |
|
|
417 |
know that this is the last fragment, so we can calculate the |
|
|
418 |
size of the entire packet. We also set the |
|
|
419 |
IP_REASS_FLAG_LASTFRAG flag to indicate that we have received |
|
|
420 |
the final fragment. */ |
|
|
421 |
|
|
|
422 |
if((BUF->ipoffset[0] & IP_MF) == 0) { |
|
|
423 |
uip_reassflags |= UIP_REASS_FLAG_LASTFRAG; |
|
|
424 |
uip_reasslen = offset + len; |
|
|
425 |
} |
|
|
426 |
|
|
|
427 |
/* Finally, we check if we have a full packet in the buffer. We do |
|
|
428 |
this by checking if we have the last fragment and if all bits |
|
|
429 |
in the bitmap are set. */ |
|
|
430 |
if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) { |
|
|
431 |
/* Check all bytes up to and including all but the last byte in |
|
|
432 |
the bitmap. */ |
|
|
433 |
for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) { |
|
|
434 |
if(uip_reassbitmap[i] != 0xff) { |
|
|
435 |
goto nullreturn; |
|
|
436 |
} |
|
|
437 |
} |
|
|
438 |
/* Check the last byte in the bitmap. It should contain just the |
|
|
439 |
right amount of bits. */ |
|
|
440 |
if(uip_reassbitmap[uip_reasslen / (8 * 8)] != |
|
|
441 |
(u8_t)~bitmap_bits[uip_reasslen / 8 & 7]) { |
|
|
442 |
goto nullreturn; |
|
|
443 |
} |
|
|
444 |
|
|
|
445 |
/* If we have come this far, we have a full packet in the |
|
|
446 |
buffer, so we allocate a pbuf and copy the packet into it. We |
|
|
447 |
also reset the timer. */ |
|
|
448 |
uip_reasstmr = 0; |
|
|
449 |
memcpy(BUF, FBUF, uip_reasslen); |
|
|
450 |
|
|
|
451 |
/* Pretend to be a "normal" (i.e., not fragmented) IP packet |
|
|
452 |
from now on. */ |
|
|
453 |
BUF->ipoffset[0] = BUF->ipoffset[1] = 0; |
|
|
454 |
BUF->len[0] = uip_reasslen >> 8; |
|
|
455 |
BUF->len[1] = uip_reasslen & 0xff; |
|
|
456 |
BUF->ipchksum = 0; |
|
|
457 |
BUF->ipchksum = ~(uip_ipchksum()); |
|
|
458 |
|
|
|
459 |
return uip_reasslen; |
|
|
460 |
} |
|
|
461 |
} |
|
|
462 |
|
|
|
463 |
nullreturn: |
|
|
464 |
return 0; |
|
|
465 |
} |
|
|
466 |
#endif /* UIP_REASSEMBL */ |
|
|
467 |
/*-----------------------------------------------------------------------------------*/ |
|
|
468 |
static void |
|
|
469 |
uip_add_rcv_nxt(u16_t n) |
|
|
470 |
{ |
|
|
471 |
uip_add32(uip_conn->rcv_nxt, n); |
|
|
472 |
uip_conn->rcv_nxt[0] = uip_acc32[0]; |
|
|
473 |
uip_conn->rcv_nxt[1] = uip_acc32[1]; |
|
|
474 |
uip_conn->rcv_nxt[2] = uip_acc32[2]; |
|
|
475 |
uip_conn->rcv_nxt[3] = uip_acc32[3]; |
|
|
476 |
} |
|
|
477 |
/*-----------------------------------------------------------------------------------*/ |
|
|
478 |
void |
|
|
479 |
uip_process(u8_t flag) |
|
|
480 |
{ |
|
|
481 |
register struct uip_conn *uip_connr = uip_conn; |
|
|
482 |
|
|
|
483 |
uip_appdata = &uip_buf[40 + UIP_LLH_LEN]; |
|
|
484 |
|
|
|
485 |
|
|
|
486 |
/* Check if we were invoked because of the perodic timer fireing. */ |
|
|
487 |
if(flag == UIP_TIMER) { |
|
|
488 |
#if UIP_REASSEMBLY |
|
|
489 |
if(uip_reasstmr != 0) { |
|
|
490 |
--uip_reasstmr; |
|
|
491 |
} |
|
|
492 |
#endif /* UIP_REASSEMBLY */ |
|
|
493 |
/* Increase the initial sequence number. */ |
|
|
494 |
if(++iss[3] == 0) { |
|
|
495 |
if(++iss[2] == 0) { |
|
|
496 |
if(++iss[1] == 0) { |
|
|
497 |
++iss[0]; |
|
|
498 |
} |
|
|
499 |
} |
|
|
500 |
} |
|
|
501 |
uip_len = 0; |
|
|
502 |
if(uip_connr->tcpstateflags == TIME_WAIT || |
|
|
503 |
uip_connr->tcpstateflags == FIN_WAIT_2) { |
|
|
504 |
++(uip_connr->timer); |
|
|
505 |
if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) { |
|
|
506 |
uip_connr->tcpstateflags = CLOSED; |
|
|
507 |
} |
|
|
508 |
} else if(uip_connr->tcpstateflags != CLOSED) { |
|
|
509 |
/* If the connection has outstanding data, we increase the |
|
|
510 |
connection's timer and see if it has reached the RTO value |
|
|
511 |
in which case we retransmit. */ |
|
|
512 |
if(uip_outstanding(uip_connr)) { |
|
|
513 |
if(uip_connr->timer-- == 0) { |
|
|
514 |
if(uip_connr->nrtx == UIP_MAXRTX || |
|
|
515 |
((uip_connr->tcpstateflags == SYN_SENT || |
|
|
516 |
uip_connr->tcpstateflags == SYN_RCVD) && |
|
|
517 |
uip_connr->nrtx == UIP_MAXSYNRTX)) { |
|
|
518 |
uip_connr->tcpstateflags = CLOSED; |
|
|
519 |
|
|
|
520 |
/* We call UIP_APPCALL() with uip_flags set to |
|
|
521 |
UIP_TIMEDOUT to inform the application that the |
|
|
522 |
connection has timed out. */ |
|
|
523 |
uip_flags = UIP_TIMEDOUT; |
|
|
524 |
UIP_APPCALL(); |
|
|
525 |
|
|
|
526 |
/* We also send a reset packet to the remote host. */ |
|
|
527 |
BUF->flags = TCP_RST | TCP_ACK; |
|
|
528 |
goto tcp_send_nodata; |
|
|
529 |
} |
|
|
530 |
|
|
|
531 |
/* Exponential backoff. */ |
|
|
532 |
uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4? |
|
|
533 |
4: |
|
|
534 |
uip_connr->nrtx); |
|
|
535 |
++(uip_connr->nrtx); |
|
|
536 |
|
|
|
537 |
/* Ok, so we need to retransmit. We do this differently |
|
|
538 |
depending on which state we are in. In ESTABLISHED, we |
|
|
539 |
call upon the application so that it may prepare the |
|
|
540 |
data for the retransmit. In SYN_RCVD, we resend the |
|
|
541 |
SYNACK that we sent earlier and in LAST_ACK we have to |
|
|
542 |
retransmit our FINACK. */ |
|
|
543 |
UIP_STAT(++uip_stat.tcp.rexmit); |
|
|
544 |
switch(uip_connr->tcpstateflags & TS_MASK) { |
|
|
545 |
case SYN_RCVD: |
|
|
546 |
/* In the SYN_RCVD state, we should retransmit our |
|
|
547 |
SYNACK. */ |
|
|
548 |
goto tcp_send_synack; |
|
|
549 |
|
|
|
550 |
#if UIP_ACTIVE_OPEN |
|
|
551 |
case SYN_SENT: |
|
|
552 |
/* In the SYN_SENT state, we retransmit out SYN. */ |
|
|
553 |
BUF->flags = 0; |
|
|
554 |
goto tcp_send_syn; |
|
|
555 |
#endif /* UIP_ACTIVE_OPEN */ |
|
|
556 |
|
|
|
557 |
case ESTABLISHED: |
|
|
558 |
/* In the ESTABLISHED state, we call upon the application |
|
|
559 |
to do the actual retransmit after which we jump into |
|
|
560 |
the code for sending out the packet (the apprexmit |
|
|
561 |
label). */ |
|
|
562 |
uip_len = 0; |
|
|
563 |
uip_slen = 0; |
|
|
564 |
uip_flags = UIP_REXMIT; |
|
|
565 |
UIP_APPCALL(); |
|
|
566 |
goto apprexmit; |
|
|
567 |
|
|
|
568 |
case FIN_WAIT_1: |
|
|
569 |
case CLOSING: |
|
|
570 |
case LAST_ACK: |
|
|
571 |
/* In all these states we should retransmit a FINACK. */ |
|
|
572 |
goto tcp_send_finack; |
|
|
573 |
|
|
|
574 |
} |
|
|
575 |
} |
|
|
576 |
} else if((uip_connr->tcpstateflags & TS_MASK) == ESTABLISHED) { |
|
|
577 |
/* If there was no need for a retransmission, we poll the |
|
|
578 |
application for new data. */ |
|
|
579 |
uip_len = 0; |
|
|
580 |
uip_slen = 0; |
|
|
581 |
uip_flags = UIP_POLL; |
|
|
582 |
UIP_APPCALL(); |
|
|
583 |
goto appsend; |
|
|
584 |
} |
|
|
585 |
} |
|
|
586 |
goto drop; |
|
|
587 |
} |
|
|
588 |
#if UIP_UDP |
|
|
589 |
if(flag == UIP_UDP_TIMER) { |
|
|
590 |
if(uip_udp_conn->lport != 0) { |
|
|
591 |
uip_appdata = &uip_buf[UIP_LLH_LEN + 28]; |
|
|
592 |
uip_len = uip_slen = 0; |
|
|
593 |
uip_flags = UIP_POLL; |
|
|
594 |
UIP_UDP_APPCALL(); |
|
|
595 |
goto udp_send; |
|
|
596 |
} else { |
|
|
597 |
goto drop; |
|
|
598 |
} |
|
|
599 |
} |
|
|
600 |
#endif |
|
|
601 |
|
|
|
602 |
/* This is where the input processing starts. */ |
|
|
603 |
UIP_STAT(++uip_stat.ip.recv); |
|
|
604 |
|
|
|
605 |
|
|
|
606 |
/* Start of IPv4 input header processing code. */ |
|
|
607 |
|
|
|
608 |
/* Check validity of the IP header. */ |
|
|
609 |
if(BUF->vhl != 0x45) { /* IP version and header length. */ |
|
|
610 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
611 |
UIP_STAT(++uip_stat.ip.vhlerr); |
|
|
612 |
UIP_LOG("ip: invalid version or header length."); |
|
|
613 |
goto drop; |
|
|
614 |
} |
|
|
615 |
|
|
|
616 |
/* Check the size of the packet. If the size reported to us in |
|
|
617 |
uip_len doesn't match the size reported in the IP header, there |
|
|
618 |
has been a transmission error and we drop the packet. */ |
|
|
619 |
|
|
|
620 |
if(BUF->len[0] != (uip_len >> 8)) { /* IP length, high byte. */ |
|
|
621 |
uip_len = (uip_len & 0xff) | (BUF->len[0] << 8); |
|
|
622 |
} |
|
|
623 |
if(BUF->len[1] != (uip_len & 0xff)) { /* IP length, low byte. */ |
|
|
624 |
uip_len = (uip_len & 0xff00) | BUF->len[1]; |
|
|
625 |
} |
|
|
626 |
|
|
|
627 |
/* Check the fragment flag. */ |
|
|
628 |
if((BUF->ipoffset[0] & 0x3f) != 0 || |
|
|
629 |
BUF->ipoffset[1] != 0) { |
|
|
630 |
#if UIP_REASSEMBLY |
|
|
631 |
uip_len = uip_reass(); |
|
|
632 |
if(uip_len == 0) { |
|
|
633 |
goto drop; |
|
|
634 |
} |
|
|
635 |
#else |
|
|
636 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
637 |
UIP_STAT(++uip_stat.ip.fragerr); |
|
|
638 |
UIP_LOG("ip: fragment dropped."); |
|
|
639 |
goto drop; |
|
|
640 |
#endif /* UIP_REASSEMBLY */ |
|
|
641 |
} |
|
|
642 |
|
|
|
643 |
/* If we are configured to use ping IP address configuration and |
|
|
644 |
hasn't been assigned an IP address yet, we accept all ICMP |
|
|
645 |
packets. */ |
|
|
646 |
#if UIP_PINGADDRCONF |
|
|
647 |
if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) { |
|
|
648 |
if(BUF->proto == UIP_PROTO_ICMP) { |
|
|
649 |
UIP_LOG("ip: possible ping config packet received."); |
|
|
650 |
goto icmp_input; |
|
|
651 |
} else { |
|
|
652 |
UIP_LOG("ip: packet dropped since no address assigned."); |
|
|
653 |
goto drop; |
|
|
654 |
} |
|
|
655 |
} |
|
|
656 |
#endif /* UIP_PINGADDRCONF */ |
|
|
657 |
|
|
|
658 |
/* Check if the packet is destined for our IP address. */ |
|
|
659 |
if(BUF->destipaddr[0] != uip_hostaddr[0]) { |
|
|
660 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
661 |
UIP_LOG("ip: packet not for us."); |
|
|
662 |
goto drop; |
|
|
663 |
} |
|
|
664 |
if(BUF->destipaddr[1] != uip_hostaddr[1]) { |
|
|
665 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
666 |
UIP_LOG("ip: packet not for us."); |
|
|
667 |
goto drop; |
|
|
668 |
} |
|
|
669 |
|
|
|
670 |
#if 0 |
|
|
671 |
// IP checksum is wrong through Netgear DSL router |
|
|
672 |
if (uip_ipchksum() != 0xffff) { /* Compute and check the IP header |
|
|
673 |
checksum. */ |
|
|
674 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
675 |
UIP_STAT(++uip_stat.ip.chkerr); |
|
|
676 |
UIP_LOG("ip: bad checksum."); |
|
|
677 |
goto drop; |
|
|
678 |
} |
|
|
679 |
#endif |
|
|
680 |
|
|
|
681 |
if(BUF->proto == UIP_PROTO_TCP) /* Check for TCP packet. If so, jump |
|
|
682 |
to the tcp_input label. */ |
|
|
683 |
goto tcp_input; |
|
|
684 |
|
|
|
685 |
#if UIP_UDP |
|
|
686 |
if(BUF->proto == UIP_PROTO_UDP) |
|
|
687 |
goto udp_input; |
|
|
688 |
#endif /* UIP_UDP */ |
|
|
689 |
|
|
|
690 |
if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from |
|
|
691 |
here. */ |
|
|
692 |
UIP_STAT(++uip_stat.ip.drop); |
|
|
693 |
UIP_STAT(++uip_stat.ip.protoerr); |
|
|
694 |
UIP_LOG("ip: neither tcp nor icmp."); |
|
|
695 |
goto drop; |
|
|
696 |
} |
|
|
697 |
|
|
|
698 |
#if UIP_PINGADDRCONF |
|
|
699 |
icmp_input: |
|
|
700 |
#endif |
|
|
701 |
UIP_STAT(++uip_stat.icmp.recv); |
|
|
702 |
|
|
|
703 |
/* ICMP echo (i.e., ping) processing. This is simple, we only change |
|
|
704 |
the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP |
|
|
705 |
checksum before we return the packet. */ |
|
|
706 |
if(ICMPBUF->type != ICMP_ECHO) { |
|
|
707 |
UIP_STAT(++uip_stat.icmp.drop); |
|
|
708 |
UIP_STAT(++uip_stat.icmp.typeerr); |
|
|
709 |
UIP_LOG("icmp: not icmp echo."); |
|
|
710 |
goto drop; |
|
|
711 |
} |
|
|
712 |
|
|
|
713 |
/* If we are configured to use ping IP address assignment, we use |
|
|
714 |
the destination IP address of this ping packet and assign it to |
|
|
715 |
ourself. */ |
|
|
716 |
#if UIP_PINGADDRCONF |
|
|
717 |
if((uip_hostaddr[0] | uip_hostaddr[1]) == 0) { |
|
|
718 |
uip_hostaddr[0] = BUF->destipaddr[0]; |
|
|
719 |
uip_hostaddr[1] = BUF->destipaddr[1]; |
|
|
720 |
} |
|
|
721 |
#endif /* UIP_PINGADDRCONF */ |
|
|
722 |
|
|
|
723 |
ICMPBUF->type = ICMP_ECHO_REPLY; |
|
|
724 |
|
|
|
725 |
if(ICMPBUF->icmpchksum >= HTONS(0xffff - (ICMP_ECHO << 8))) { |
|
|
726 |
ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8) + 1; |
|
|
727 |
} else { |
|
|
728 |
ICMPBUF->icmpchksum += HTONS(ICMP_ECHO << 8); |
|
|
729 |
} |
|
|
730 |
|
|
|
731 |
/* Swap IP addresses. */ |
|
|
732 |
tmp16 = BUF->destipaddr[0]; |
|
|
733 |
BUF->destipaddr[0] = BUF->srcipaddr[0]; |
|
|
734 |
BUF->srcipaddr[0] = tmp16; |
|
|
735 |
tmp16 = BUF->destipaddr[1]; |
|
|
736 |
BUF->destipaddr[1] = BUF->srcipaddr[1]; |
|
|
737 |
BUF->srcipaddr[1] = tmp16; |
|
|
738 |
|
|
|
739 |
UIP_STAT(++uip_stat.icmp.sent); |
|
|
740 |
goto send; |
|
|
741 |
|
|
|
742 |
/* End of IPv4 input header processing code. */ |
|
|
743 |
|
|
|
744 |
|
|
|
745 |
#if UIP_UDP |
|
|
746 |
/* UDP input processing. */ |
|
|
747 |
udp_input: |
|
|
748 |
/* UDP processing is really just a hack. We don't do anything to the |
|
|
749 |
UDP/IP headers, but let the UDP application do all the hard |
|
|
750 |
work. If the application sets uip_slen, it has a packet to |
|
|
751 |
send. */ |
|
|
752 |
#if UIP_UDP_CHECKSUMS |
|
|
753 |
if(uip_udpchksum() != 0xffff) { |
|
|
754 |
UIP_STAT(++uip_stat.udp.drop); |
|
|
755 |
UIP_STAT(++uip_stat.udp.chkerr); |
|
|
756 |
UIP_LOG("udp: bad checksum."); |
|
|
757 |
goto drop; |
|
|
758 |
} |
|
|
759 |
#endif /* UIP_UDP_CHECKSUMS */ |
|
|
760 |
|
|
|
761 |
/* Demultiplex this UDP packet between the UDP "connections". */ |
|
|
762 |
for(uip_udp_conn = &uip_udp_conns[0]; |
|
|
763 |
uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS]; |
|
|
764 |
++uip_udp_conn) { |
|
|
765 |
if(uip_udp_conn->lport != 0 && |
|
|
766 |
UDPBUF->destport == uip_udp_conn->lport && |
|
|
767 |
(uip_udp_conn->rport == 0 || |
|
|
768 |
UDPBUF->srcport == uip_udp_conn->rport) && |
|
|
769 |
BUF->srcipaddr[0] == uip_udp_conn->ripaddr[0] && |
|
|
770 |
BUF->srcipaddr[1] == uip_udp_conn->ripaddr[1]) { |
|
|
771 |
goto udp_found; |
|
|
772 |
} |
|
|
773 |
} |
|
|
774 |
goto drop; |
|
|
775 |
|
|
|
776 |
udp_found: |
|
|
777 |
uip_len = uip_len - 28; |
|
|
778 |
uip_appdata = &uip_buf[UIP_LLH_LEN + 28]; |
|
|
779 |
uip_flags = UIP_NEWDATA; |
|
|
780 |
uip_slen = 0; |
|
|
781 |
UIP_UDP_APPCALL(); |
|
|
782 |
udp_send: |
|
|
783 |
if(uip_slen == 0) { |
|
|
784 |
goto drop; |
|
|
785 |
} |
|
|
786 |
uip_len = uip_slen + 28; |
|
|
787 |
|
|
|
788 |
BUF->len[0] = (uip_len >> 8); |
|
|
789 |
BUF->len[1] = (uip_len & 0xff); |
|
|
790 |
|
|
|
791 |
BUF->proto = UIP_PROTO_UDP; |
|
|
792 |
|
|
|
793 |
UDPBUF->udplen = HTONS(uip_slen + 8); |
|
|
794 |
UDPBUF->udpchksum = 0; |
|
|
795 |
#if UIP_UDP_CHECKSUMS |
|
|
796 |
/* Calculate UDP checksum. */ |
|
|
797 |
UDPBUF->udpchksum = ~(uip_udpchksum()); |
|
|
798 |
if(UDPBUF->udpchksum == 0) { |
|
|
799 |
UDPBUF->udpchksum = 0xffff; |
|
|
800 |
} |
|
|
801 |
#endif /* UIP_UDP_CHECKSUMS */ |
|
|
802 |
|
|
|
803 |
BUF->srcport = uip_udp_conn->lport; |
|
|
804 |
BUF->destport = uip_udp_conn->rport; |
|
|
805 |
|
|
|
806 |
BUF->srcipaddr[0] = uip_hostaddr[0]; |
|
|
807 |
BUF->srcipaddr[1] = uip_hostaddr[1]; |
|
|
808 |
BUF->destipaddr[0] = uip_udp_conn->ripaddr[0]; |
|
|
809 |
BUF->destipaddr[1] = uip_udp_conn->ripaddr[1]; |
|
|
810 |
|
|
|
811 |
uip_appdata = &uip_buf[UIP_LLH_LEN + 40]; |
|
|
812 |
goto ip_send_nolen; |
|
|
813 |
#endif /* UIP_UDP */ |
|
|
814 |
|
|
|
815 |
/* TCP input processing. */ |
|
|
816 |
tcp_input: |
|
|
817 |
UIP_STAT(++uip_stat.tcp.recv); |
|
|
818 |
|
|
|
819 |
/* Start of TCP input header processing code. */ |
|
|
820 |
|
|
|
821 |
#if 1 // FIXME |
|
|
822 |
if(uip_tcpchksum() != 0xffff) { /* Compute and check the TCP |
|
|
823 |
checksum. */ |
|
|
824 |
UIP_STAT(++uip_stat.tcp.drop); |
|
|
825 |
UIP_STAT(++uip_stat.tcp.chkerr); |
|
|
826 |
UIP_LOG("tcp: bad checksum."); |
|
|
827 |
goto drop; |
|
|
828 |
} |
|
|
829 |
#endif |
|
|
830 |
|
|
|
831 |
/* Demultiplex this segment. */ |
|
|
832 |
/* First check any active connections. */ |
|
|
833 |
for(uip_connr = &uip_conns[0]; uip_connr < &uip_conns[UIP_CONNS]; ++uip_connr) { |
|
|
834 |
if(uip_connr->tcpstateflags != CLOSED && |
|
|
835 |
BUF->destport == uip_connr->lport && |
|
|
836 |
BUF->srcport == uip_connr->rport && |
|
|
837 |
BUF->srcipaddr[0] == uip_connr->ripaddr[0] && |
|
|
838 |
BUF->srcipaddr[1] == uip_connr->ripaddr[1]) { |
|
|
839 |
goto found; |
|
|
840 |
} |
|
|
841 |
} |
|
|
842 |
|
|
|
843 |
/* If we didn't find and active connection that expected the packet, |
|
|
844 |
either this packet is an old duplicate, or this is a SYN packet |
|
|
845 |
destined for a connection in LISTEN. If the SYN flag isn't set, |
|
|
846 |
it is an old packet and we send a RST. */ |
|
|
847 |
if((BUF->flags & TCP_CTL) != TCP_SYN) |
|
|
848 |
goto reset; |
|
|
849 |
|
|
|
850 |
tmp16 = BUF->destport; |
|
|
851 |
/* Next, check listening connections. */ |
|
|
852 |
for(c = 0; c < UIP_LISTENPORTS; ++c) { |
|
|
853 |
if(tmp16 == uip_listenports[c]) |
|
|
854 |
goto found_listen; |
|
|
855 |
} |
|
|
856 |
|
|
|
857 |
/* No matching connection found, so we send a RST packet. */ |
|
|
858 |
UIP_STAT(++uip_stat.tcp.synrst); |
|
|
859 |
reset: |
|
|
860 |
|
|
|
861 |
/* We do not send resets in response to resets. */ |
|
|
862 |
if(BUF->flags & TCP_RST) |
|
|
863 |
goto drop; |
|
|
864 |
|
|
|
865 |
UIP_STAT(++uip_stat.tcp.rst); |
|
|
866 |
|
|
|
867 |
BUF->flags = TCP_RST | TCP_ACK; |
|
|
868 |
uip_len = 40; |
|
|
869 |
BUF->tcpoffset = 5 << 4; |
|
|
870 |
|
|
|
871 |
/* Flip the seqno and ackno fields in the TCP header. */ |
|
|
872 |
c = BUF->seqno[3]; |
|
|
873 |
BUF->seqno[3] = BUF->ackno[3]; |
|
|
874 |
BUF->ackno[3] = c; |
|
|
875 |
|
|
|
876 |
c = BUF->seqno[2]; |
|
|
877 |
BUF->seqno[2] = BUF->ackno[2]; |
|
|
878 |
BUF->ackno[2] = c; |
|
|
879 |
|
|
|
880 |
c = BUF->seqno[1]; |
|
|
881 |
BUF->seqno[1] = BUF->ackno[1]; |
|
|
882 |
BUF->ackno[1] = c; |
|
|
883 |
|
|
|
884 |
c = BUF->seqno[0]; |
|
|
885 |
BUF->seqno[0] = BUF->ackno[0]; |
|
|
886 |
BUF->ackno[0] = c; |
|
|
887 |
|
|
|
888 |
/* We also have to increase the sequence number we are |
|
|
889 |
acknowledging. If the least significant byte overflowed, we need |
|
|
890 |
to propagate the carry to the other bytes as well. */ |
|
|
891 |
if(++BUF->ackno[3] == 0) { |
|
|
892 |
if(++BUF->ackno[2] == 0) { |
|
|
893 |
if(++BUF->ackno[1] == 0) { |
|
|
894 |
++BUF->ackno[0]; |
|
|
895 |
} |
|
|
896 |
} |
|
|
897 |
} |
|
|
898 |
|
|
|
899 |
/* Swap port numbers. */ |
|
|
900 |
tmp16 = BUF->srcport; |
|
|
901 |
BUF->srcport = BUF->destport; |
|
|
902 |
BUF->destport = tmp16; |
|
|
903 |
|
|
|
904 |
/* Swap IP addresses. */ |
|
|
905 |
tmp16 = BUF->destipaddr[0]; |
|
|
906 |
BUF->destipaddr[0] = BUF->srcipaddr[0]; |
|
|
907 |
BUF->srcipaddr[0] = tmp16; |
|
|
908 |
tmp16 = BUF->destipaddr[1]; |
|
|
909 |
BUF->destipaddr[1] = BUF->srcipaddr[1]; |
|
|
910 |
BUF->srcipaddr[1] = tmp16; |
|
|
911 |
|
|
|
912 |
|
|
|
913 |
/* And send out the RST packet! */ |
|
|
914 |
goto tcp_send_noconn; |
|
|
915 |
|
|
|
916 |
/* This label will be jumped to if we matched the incoming packet |
|
|
917 |
with a connection in LISTEN. In that case, we should create a new |
|
|
918 |
connection and send a SYNACK in return. */ |
|
|
919 |
found_listen: |
|
|
920 |
/* First we check if there are any connections avaliable. Unused |
|
|
921 |
connections are kept in the same table as used connections, but |
|
|
922 |
unused ones have the tcpstate set to CLOSED. Also, connections in |
|
|
923 |
TIME_WAIT are kept track of and we'll use the oldest one if no |
|
|
924 |
CLOSED connections are found. Thanks to Eddie C. Dost for a very |
|
|
925 |
nice algorithm for the TIME_WAIT search. */ |
|
|
926 |
uip_connr = 0; |
|
|
927 |
for(c = 0; c < UIP_CONNS; ++c) { |
|
|
928 |
if(uip_conns[c].tcpstateflags == CLOSED) { |
|
|
929 |
uip_connr = &uip_conns[c]; |
|
|
930 |
break; |
|
|
931 |
} |
|
|
932 |
if(uip_conns[c].tcpstateflags == TIME_WAIT) { |
|
|
933 |
if(uip_connr == 0 || |
|
|
934 |
uip_conns[c].timer > uip_connr->timer) { |
|
|
935 |
uip_connr = &uip_conns[c]; |
|
|
936 |
} |
|
|
937 |
} |
|
|
938 |
} |
|
|
939 |
|
|
|
940 |
if(uip_connr == 0) { |
|
|
941 |
/* All connections are used already, we drop packet and hope that |
|
|
942 |
the remote end will retransmit the packet at a time when we |
|
|
943 |
have more spare connections. */ |
|
|
944 |
UIP_STAT(++uip_stat.tcp.syndrop); |
|
|
945 |
UIP_LOG("tcp: found no unused connections."); |
|
|
946 |
goto drop; |
|
|
947 |
} |
|
|
948 |
uip_conn = uip_connr; |
|
|
949 |
|
|
|
950 |
/* Fill in the necessary fields for the new connection. */ |
|
|
951 |
uip_connr->rto = uip_connr->timer = UIP_RTO; |
|
|
952 |
uip_connr->sa = 0; |
|
|
953 |
uip_connr->sv = 4; |
|
|
954 |
uip_connr->nrtx = 0; |
|
|
955 |
uip_connr->lport = BUF->destport; |
|
|
956 |
uip_connr->rport = BUF->srcport; |
|
|
957 |
uip_connr->ripaddr[0] = BUF->srcipaddr[0]; |
|
|
958 |
uip_connr->ripaddr[1] = BUF->srcipaddr[1]; |
|
|
959 |
uip_connr->tcpstateflags = SYN_RCVD; |
|
|
960 |
|
|
|
961 |
uip_connr->snd_nxt[0] = iss[0]; |
|
|
962 |
uip_connr->snd_nxt[1] = iss[1]; |
|
|
963 |
uip_connr->snd_nxt[2] = iss[2]; |
|
|
964 |
uip_connr->snd_nxt[3] = iss[3]; |
|
|
965 |
uip_connr->len = 1; |
|
|
966 |
|
|
|
967 |
/* rcv_nxt should be the seqno from the incoming packet + 1. */ |
|
|
968 |
uip_connr->rcv_nxt[3] = BUF->seqno[3]; |
|
|
969 |
uip_connr->rcv_nxt[2] = BUF->seqno[2]; |
|
|
970 |
uip_connr->rcv_nxt[1] = BUF->seqno[1]; |
|
|
971 |
uip_connr->rcv_nxt[0] = BUF->seqno[0]; |
|
|
972 |
uip_add_rcv_nxt(1); |
|
|
973 |
|
|
|
974 |
/* Parse the TCP MSS option, if present. */ |
|
|
975 |
if((BUF->tcpoffset & 0xf0) > 0x50) { |
|
|
976 |
for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) { |
|
|
977 |
opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c]; |
|
|
978 |
if(opt == 0x00) { |
|
|
979 |
/* End of options. */ |
|
|
980 |
break; |
|
|
981 |
} else if(opt == 0x01) { |
|
|
982 |
++c; |
|
|
983 |
/* NOP option. */ |
|
|
984 |
} else if(opt == 0x02 && |
|
|
985 |
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) { |
|
|
986 |
/* An MSS option with the right option length. */ |
|
|
987 |
tmp16 = ((u16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | |
|
|
988 |
(u16_t)uip_buf[40 + UIP_LLH_LEN + 3 + c]; |
|
|
989 |
uip_connr->initialmss = uip_connr->mss = |
|
|
990 |
tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; |
|
|
991 |
|
|
|
992 |
/* And we are done processing options. */ |
|
|
993 |
break; |
|
|
994 |
} else { |
|
|
995 |
/* All other options have a length field, so that we easily |
|
|
996 |
can skip past them. */ |
|
|
997 |
if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) { |
|
|
998 |
/* If the length field is zero, the options are malformed |
|
|
999 |
and we don't process them further. */ |
|
|
1000 |
break; |
|
|
1001 |
} |
|
|
1002 |
c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c]; |
|
|
1003 |
} |
|
|
1004 |
} |
|
|
1005 |
} |
|
|
1006 |
|
|
|
1007 |
/* Our response will be a SYNACK. */ |
|
|
1008 |
#if UIP_ACTIVE_OPEN |
|
|
1009 |
tcp_send_synack: |
|
|
1010 |
BUF->flags = TCP_ACK; |
|
|
1011 |
|
|
|
1012 |
tcp_send_syn: |
|
|
1013 |
BUF->flags |= TCP_SYN; |
|
|
1014 |
#else /* UIP_ACTIVE_OPEN */ |
|
|
1015 |
tcp_send_synack: |
|
|
1016 |
BUF->flags = TCP_SYN | TCP_ACK; |
|
|
1017 |
#endif /* UIP_ACTIVE_OPEN */ |
|
|
1018 |
|
|
|
1019 |
/* We send out the TCP Maximum Segment Size option with our |
|
|
1020 |
SYNACK. */ |
|
|
1021 |
BUF->optdata[0] = 2; |
|
|
1022 |
BUF->optdata[1] = 4; |
|
|
1023 |
BUF->optdata[2] = (UIP_TCP_MSS) / 256; |
|
|
1024 |
BUF->optdata[3] = (UIP_TCP_MSS) & 255; |
|
|
1025 |
uip_len = 44; |
|
|
1026 |
BUF->tcpoffset = 6 << 4; |
|
|
1027 |
goto tcp_send; |
|
|
1028 |
|
|
|
1029 |
/* This label will be jumped to if we found an active connection. */ |
|
|
1030 |
found: |
|
|
1031 |
uip_conn = uip_connr; |
|
|
1032 |
uip_flags = 0; |
|
|
1033 |
|
|
|
1034 |
/* We do a very naive form of TCP reset processing; we just accept |
|
|
1035 |
any RST and kill our connection. We should in fact check if the |
|
|
1036 |
sequence number of this reset is wihtin our advertised window |
|
|
1037 |
before we accept the reset. */ |
|
|
1038 |
if(BUF->flags & TCP_RST) { |
|
|
1039 |
uip_connr->tcpstateflags = CLOSED; |
|
|
1040 |
UIP_LOG("tcp: got reset, aborting connection."); |
|
|
1041 |
uip_flags = UIP_ABORT; |
|
|
1042 |
UIP_APPCALL(); |
|
|
1043 |
goto drop; |
|
|
1044 |
} |
|
|
1045 |
/* Calculated the length of the data, if the application has sent |
|
|
1046 |
any data to us. */ |
|
|
1047 |
c = (BUF->tcpoffset >> 4) << 2; |
|
|
1048 |
/* uip_len will contain the length of the actual TCP data. This is |
|
|
1049 |
calculated by subtracing the length of the TCP header (in |
|
|
1050 |
c) and the length of the IP header (20 bytes). */ |
|
|
1051 |
uip_len = uip_len - c - 20; |
|
|
1052 |
|
|
|
1053 |
/* First, check if the sequence number of the incoming packet is |
|
|
1054 |
what we're expecting next. If not, we send out an ACK with the |
|
|
1055 |
correct numbers in. */ |
|
|
1056 |
if(uip_len > 0 && |
|
|
1057 |
(BUF->seqno[0] != uip_connr->rcv_nxt[0] || |
|
|
1058 |
BUF->seqno[1] != uip_connr->rcv_nxt[1] || |
|
|
1059 |
BUF->seqno[2] != uip_connr->rcv_nxt[2] || |
|
|
1060 |
BUF->seqno[3] != uip_connr->rcv_nxt[3])) { |
|
|
1061 |
goto tcp_send_ack; |
|
|
1062 |
} |
|
|
1063 |
|
|
|
1064 |
/* Next, check if the incoming segment acknowledges any outstanding |
|
|
1065 |
data. If so, we update the sequence number, reset the length of |
|
|
1066 |
the outstanding data, calculate RTT estimations, and reset the |
|
|
1067 |
retransmission timer. */ |
|
|
1068 |
if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) { |
|
|
1069 |
uip_add32(uip_connr->snd_nxt, uip_connr->len); |
|
|
1070 |
if(BUF->ackno[0] == uip_acc32[0] && |
|
|
1071 |
BUF->ackno[1] == uip_acc32[1] && |
|
|
1072 |
BUF->ackno[2] == uip_acc32[2] && |
|
|
1073 |
BUF->ackno[3] == uip_acc32[3]) { |
|
|
1074 |
/* Update sequence number. */ |
|
|
1075 |
uip_connr->snd_nxt[0] = uip_acc32[0]; |
|
|
1076 |
uip_connr->snd_nxt[1] = uip_acc32[1]; |
|
|
1077 |
uip_connr->snd_nxt[2] = uip_acc32[2]; |
|
|
1078 |
uip_connr->snd_nxt[3] = uip_acc32[3]; |
|
|
1079 |
|
|
|
1080 |
|
|
|
1081 |
/* Do RTT estimation, unless we have done retransmissions. */ |
|
|
1082 |
if(uip_connr->nrtx == 0) { |
|
|
1083 |
signed char m; |
|
|
1084 |
m = uip_connr->rto - uip_connr->timer; |
|
|
1085 |
/* This is taken directly from VJs original code in his paper */ |
|
|
1086 |
m = m - (uip_connr->sa >> 3); |
|
|
1087 |
uip_connr->sa += m; |
|
|
1088 |
if(m < 0) { |
|
|
1089 |
m = -m; |
|
|
1090 |
} |
|
|
1091 |
m = m - (uip_connr->sv >> 2); |
|
|
1092 |
uip_connr->sv += m; |
|
|
1093 |
uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv; |
|
|
1094 |
|
|
|
1095 |
} |
|
|
1096 |
/* Set the acknowledged flag. */ |
|
|
1097 |
uip_flags = UIP_ACKDATA; |
|
|
1098 |
/* Reset the retransmission timer. */ |
|
|
1099 |
uip_connr->timer = uip_connr->rto; |
|
|
1100 |
} |
|
|
1101 |
|
|
|
1102 |
} |
|
|
1103 |
|
|
|
1104 |
/* Do different things depending on in what state the connection is. */ |
|
|
1105 |
switch(uip_connr->tcpstateflags & TS_MASK) { |
|
|
1106 |
/* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not |
|
|
1107 |
implemented, since we force the application to close when the |
|
|
1108 |
peer sends a FIN (hence the application goes directly from |
|
|
1109 |
ESTABLISHED to LAST_ACK). */ |
|
|
1110 |
case SYN_RCVD: |
|
|
1111 |
/* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and |
|
|
1112 |
we are waiting for an ACK that acknowledges the data we sent |
|
|
1113 |
out the last time. Therefore, we want to have the UIP_ACKDATA |
|
|
1114 |
flag set. If so, we enter the ESTABLISHED state. */ |
|
|
1115 |
if(uip_flags & UIP_ACKDATA) { |
|
|
1116 |
uip_connr->tcpstateflags = ESTABLISHED; |
|
|
1117 |
uip_flags = UIP_CONNECTED; |
|
|
1118 |
uip_connr->len = 0; |
|
|
1119 |
if(uip_len > 0) { |
|
|
1120 |
uip_flags |= UIP_NEWDATA; |
|
|
1121 |
uip_add_rcv_nxt(uip_len); |
|
|
1122 |
} |
|
|
1123 |
uip_slen = 0; |
|
|
1124 |
UIP_APPCALL(); |
|
|
1125 |
goto appsend; |
|
|
1126 |
} |
|
|
1127 |
goto drop; |
|
|
1128 |
#if UIP_ACTIVE_OPEN |
|
|
1129 |
case SYN_SENT: |
|
|
1130 |
/* In SYN_SENT, we wait for a SYNACK that is sent in response to |
|
|
1131 |
our SYN. The rcv_nxt is set to sequence number in the SYNACK |
|
|
1132 |
plus one, and we send an ACK. We move into the ESTABLISHED |
|
|
1133 |
state. */ |
|
|
1134 |
if((uip_flags & UIP_ACKDATA) && |
|
|
1135 |
BUF->flags == (TCP_SYN | TCP_ACK)) { |
|
|
1136 |
|
|
|
1137 |
/* Parse the TCP MSS option, if present. */ |
|
|
1138 |
if((BUF->tcpoffset & 0xf0) > 0x50) { |
|
|
1139 |
for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) { |
|
|
1140 |
opt = uip_buf[40 + UIP_LLH_LEN + c]; |
|
|
1141 |
if(opt == 0x00) { |
|
|
1142 |
/* End of options. */ |
|
|
1143 |
break; |
|
|
1144 |
} else if(opt == 0x01) { |
|
|
1145 |
++c; |
|
|
1146 |
/* NOP option. */ |
|
|
1147 |
} else if(opt == 0x02 && |
|
|
1148 |
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0x04) { |
|
|
1149 |
/* An MSS option with the right option length. */ |
|
|
1150 |
tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) | |
|
|
1151 |
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c]; |
|
|
1152 |
uip_connr->initialmss = |
|
|
1153 |
uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16; |
|
|
1154 |
|
|
|
1155 |
/* And we are done processing options. */ |
|
|
1156 |
break; |
|
|
1157 |
} else { |
|
|
1158 |
/* All other options have a length field, so that we easily |
|
|
1159 |
can skip past them. */ |
|
|
1160 |
if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) { |
|
|
1161 |
/* If the length field is zero, the options are malformed |
|
|
1162 |
and we don't process them further. */ |
|
|
1163 |
break; |
|
|
1164 |
} |
|
|
1165 |
c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c]; |
|
|
1166 |
} |
|
|
1167 |
} |
|
|
1168 |
} |
|
|
1169 |
uip_connr->tcpstateflags = ESTABLISHED; |
|
|
1170 |
uip_connr->rcv_nxt[0] = BUF->seqno[0]; |
|
|
1171 |
uip_connr->rcv_nxt[1] = BUF->seqno[1]; |
|
|
1172 |
uip_connr->rcv_nxt[2] = BUF->seqno[2]; |
|
|
1173 |
uip_connr->rcv_nxt[3] = BUF->seqno[3]; |
|
|
1174 |
uip_add_rcv_nxt(1); |
|
|
1175 |
uip_flags = UIP_CONNECTED | UIP_NEWDATA; |
|
|
1176 |
uip_connr->len = 0; |
|
|
1177 |
uip_len = 0; |
|
|
1178 |
uip_slen = 0; |
|
|
1179 |
UIP_APPCALL(); |
|
|
1180 |
goto appsend; |
|
|
1181 |
} |
|
|
1182 |
goto reset; |
|
|
1183 |
#endif /* UIP_ACTIVE_OPEN */ |
|
|
1184 |
|
|
|
1185 |
case ESTABLISHED: |
|
|
1186 |
/* In the ESTABLISHED state, we call upon the application to feed |
|
|
1187 |
data into the uip_buf. If the UIP_ACKDATA flag is set, the |
|
|
1188 |
application should put new data into the buffer, otherwise we are |
|
|
1189 |
retransmitting an old segment, and the application should put that |
|
|
1190 |
data into the buffer. |
|
|
1191 |
|
|
|
1192 |
If the incoming packet is a FIN, we should close the connection on |
|
|
1193 |
this side as well, and we send out a FIN and enter the LAST_ACK |
|
|
1194 |
state. We require that there is no outstanding data; otherwise the |
|
|
1195 |
sequence numbers will be screwed up. */ |
|
|
1196 |
|
|
|
1197 |
if(BUF->flags & TCP_FIN) { |
|
|
1198 |
if(uip_outstanding(uip_connr)) { |
|
|
1199 |
goto drop; |
|
|
1200 |
} |
|
|
1201 |
uip_add_rcv_nxt(1 + uip_len); |
|
|
1202 |
uip_flags = UIP_CLOSE; |
|
|
1203 |
if(uip_len > 0) { |
|
|
1204 |
uip_flags |= UIP_NEWDATA; |
|
|
1205 |
} |
|
|
1206 |
UIP_APPCALL(); |
|
|
1207 |
uip_connr->len = 1; |
|
|
1208 |
uip_connr->tcpstateflags = LAST_ACK; |
|
|
1209 |
uip_connr->nrtx = 0; |
|
|
1210 |
tcp_send_finack: |
|
|
1211 |
BUF->flags = TCP_FIN | TCP_ACK; |
|
|
1212 |
goto tcp_send_nodata; |
|
|
1213 |
} |
|
|
1214 |
|
|
|
1215 |
/* Check the URG flag. If this is set, the segment carries urgent |
|
|
1216 |
data that we must pass to the application. */ |
|
|
1217 |
if(BUF->flags & TCP_URG) { |
|
|
1218 |
#if UIP_URGDATA > 0 |
|
|
1219 |
uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1]; |
|
|
1220 |
if(uip_urglen > uip_len) { |
|
|
1221 |
/* There is more urgent data in the next segment to come. */ |
|
|
1222 |
uip_urglen = uip_len; |
|
|
1223 |
} |
|
|
1224 |
uip_add_rcv_nxt(uip_urglen); |
|
|
1225 |
uip_len -= uip_urglen; |
|
|
1226 |
uip_urgdata = uip_appdata; |
|
|
1227 |
uip_appdata += uip_urglen; |
|
|
1228 |
} else { |
|
|
1229 |
uip_urglen = 0; |
|
|
1230 |
#endif /* UIP_URGDATA > 0 */ |
|
|
1231 |
uip_appdata += (BUF->urgp[0] << 8) | BUF->urgp[1]; |
|
|
1232 |
uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1]; |
|
|
1233 |
} |
|
|
1234 |
|
|
|
1235 |
|
|
|
1236 |
/* If uip_len > 0 we have TCP data in the packet, and we flag this |
|
|
1237 |
by setting the UIP_NEWDATA flag and update the sequence number |
|
|
1238 |
we acknowledge. If the application has stopped the dataflow |
|
|
1239 |
using uip_stop(), we must not accept any data packets from the |
|
|
1240 |
remote host. */ |
|
|
1241 |
if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) { |
|
|
1242 |
uip_flags |= UIP_NEWDATA; |
|
|
1243 |
uip_add_rcv_nxt(uip_len); |
|
|
1244 |
} |
|
|
1245 |
|
|
|
1246 |
/* Check if the available buffer space advertised by the other end |
|
|
1247 |
is smaller than the initial MSS for this connection. If so, we |
|
|
1248 |
set the current MSS to the window size to ensure that the |
|
|
1249 |
application does not send more data than the other end can |
|
|
1250 |
handle. |
|
|
1251 |
|
|
|
1252 |
If the remote host advertises a zero window, we set the MSS to |
|
|
1253 |
the initial MSS so that the application will send an entire MSS |
|
|
1254 |
of data. This data will not be acknowledged by the receiver, |
|
|
1255 |
and the application will retransmit it. This is called the |
|
|
1256 |
"persistent timer" and uses the retransmission mechanim. |
|
|
1257 |
*/ |
|
|
1258 |
tmp16 = ((u16_t)BUF->wnd[0] << 8) + (u16_t)BUF->wnd[1]; |
|
|
1259 |
if(tmp16 > uip_connr->initialmss || |
|
|
1260 |
tmp16 == 0) { |
|
|
1261 |
tmp16 = uip_connr->initialmss; |
|
|
1262 |
} |
|
|
1263 |
uip_connr->mss = tmp16; |
|
|
1264 |
|
|
|
1265 |
/* If this packet constitutes an ACK for outstanding data (flagged |
|
|
1266 |
by the UIP_ACKDATA flag, we should call the application since it |
|
|
1267 |
might want to send more data. If the incoming packet had data |
|
|
1268 |
from the peer (as flagged by the UIP_NEWDATA flag), the |
|
|
1269 |
application must also be notified. |
|
|
1270 |
|
|
|
1271 |
When the application is called, the global variable uip_len |
|
|
1272 |
contains the length of the incoming data. The application can |
|
|
1273 |
access the incoming data through the global pointer |
|
|
1274 |
uip_appdata, which usually points 40 bytes into the uip_buf |
|
|
1275 |
array. |
|
|
1276 |
|
|
|
1277 |
If the application wishes to send any data, this data should be |
|
|
1278 |
put into the uip_appdata and the length of the data should be |
|
|
1279 |
put into uip_len. If the application don't have any data to |
|
|
1280 |
send, uip_len must be set to 0. */ |
|
|
1281 |
if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) { |
|
|
1282 |
uip_slen = 0; |
|
|
1283 |
UIP_APPCALL(); |
|
|
1284 |
|
|
|
1285 |
appsend: |
|
|
1286 |
|
|
|
1287 |
if(uip_flags & UIP_ABORT) { |
|
|
1288 |
uip_slen = 0; |
|
|
1289 |
uip_connr->tcpstateflags = CLOSED; |
|
|
1290 |
BUF->flags = TCP_RST | TCP_ACK; |
|
|
1291 |
goto tcp_send_nodata; |
|
|
1292 |
} |
|
|
1293 |
|
|
|
1294 |
if(uip_flags & UIP_CLOSE) { |
|
|
1295 |
uip_slen = 0; |
|
|
1296 |
uip_connr->len = 1; |
|
|
1297 |
uip_connr->tcpstateflags = FIN_WAIT_1; |
|
|
1298 |
uip_connr->nrtx = 0; |
|
|
1299 |
BUF->flags = TCP_FIN | TCP_ACK; |
|
|
1300 |
goto tcp_send_nodata; |
|
|
1301 |
} |
|
|
1302 |
|
|
|
1303 |
/* If uip_slen > 0, the application has data to be sent. */ |
|
|
1304 |
if(uip_slen > 0) { |
|
|
1305 |
|
|
|
1306 |
/* If the connection has acknowledged data, the contents of |
|
|
1307 |
the ->len variable should be discarded. */ |
|
|
1308 |
if((uip_flags & UIP_ACKDATA) != 0) { |
|
|
1309 |
uip_connr->len = 0; |
|
|
1310 |
} |
|
|
1311 |
|
|
|
1312 |
/* If the ->len variable is non-zero the connection has |
|
|
1313 |
already data in transit and cannot send anymore right |
|
|
1314 |
now. */ |
|
|
1315 |
if(uip_connr->len == 0) { |
|
|
1316 |
|
|
|
1317 |
/* The application cannot send more than what is allowed by |
|
|
1318 |
the mss (the minumum of the MSS and the available |
|
|
1319 |
window). */ |
|
|
1320 |
if(uip_slen > uip_connr->mss) { |
|
|
1321 |
uip_slen = uip_connr->mss; |
|
|
1322 |
} |
|
|
1323 |
|
|
|
1324 |
/* Remember how much data we send out now so that we know |
|
|
1325 |
when everything has been acknowledged. */ |
|
|
1326 |
uip_connr->len = uip_slen; |
|
|
1327 |
} else { |
|
|
1328 |
|
|
|
1329 |
/* If the application already had unacknowledged data, we |
|
|
1330 |
make sure that the application does not send (i.e., |
|
|
1331 |
retransmit) out more than it previously sent out. */ |
|
|
1332 |
uip_slen = uip_connr->len; |
|
|
1333 |
} |
|
|
1334 |
} else { |
|
|
1335 |
uip_connr->len = 0; |
|
|
1336 |
} |
|
|
1337 |
uip_connr->nrtx = 0; |
|
|
1338 |
apprexmit: |
|
|
1339 |
uip_appdata = uip_sappdata; |
|
|
1340 |
|
|
|
1341 |
/* If the application has data to be sent, or if the incoming |
|
|
1342 |
packet had new data in it, we must send out a packet. */ |
|
|
1343 |
if(uip_slen > 0 && uip_connr->len > 0) { |
|
|
1344 |
/* Add the length of the IP and TCP headers. */ |
|
|
1345 |
uip_len = uip_connr->len + UIP_TCPIP_HLEN; |
|
|
1346 |
/* We always set the ACK flag in response packets. */ |
|
|
1347 |
BUF->flags = TCP_ACK | TCP_PSH; |
|
|
1348 |
/* Send the packet. */ |
|
|
1349 |
goto tcp_send_noopts; |
|
|
1350 |
} |
|
|
1351 |
/* If there is no data to send, just send out a pure ACK if |
|
|
1352 |
there is newdata. */ |
|
|
1353 |
if(uip_flags & UIP_NEWDATA) { |
|
|
1354 |
uip_len = UIP_TCPIP_HLEN; |
|
|
1355 |
BUF->flags = TCP_ACK; |
|
|
1356 |
goto tcp_send_noopts; |
|
|
1357 |
} |
|
|
1358 |
} |
|
|
1359 |
goto drop; |
|
|
1360 |
case LAST_ACK: |
|
|
1361 |
/* We can close this connection if the peer has acknowledged our |
|
|
1362 |
FIN. This is indicated by the UIP_ACKDATA flag. */ |
|
|
1363 |
if(uip_flags & UIP_ACKDATA) { |
|
|
1364 |
uip_connr->tcpstateflags = CLOSED; |
|
|
1365 |
uip_flags = UIP_CLOSE; |
|
|
1366 |
UIP_APPCALL(); |
|
|
1367 |
} |
|
|
1368 |
break; |
|
|
1369 |
|
|
|
1370 |
case FIN_WAIT_1: |
|
|
1371 |
/* The application has closed the connection, but the remote host |
|
|
1372 |
hasn't closed its end yet. Thus we do nothing but wait for a |
|
|
1373 |
FIN from the other side. */ |
|
|
1374 |
if(uip_len > 0) { |
|
|
1375 |
uip_add_rcv_nxt(uip_len); |
|
|
1376 |
} |
|
|
1377 |
if(BUF->flags & TCP_FIN) { |
|
|
1378 |
if(uip_flags & UIP_ACKDATA) { |
|
|
1379 |
uip_connr->tcpstateflags = TIME_WAIT; |
|
|
1380 |
uip_connr->timer = 0; |
|
|
1381 |
uip_connr->len = 0; |
|
|
1382 |
} else { |
|
|
1383 |
uip_connr->tcpstateflags = CLOSING; |
|
|
1384 |
} |
|
|
1385 |
uip_add_rcv_nxt(1); |
|
|
1386 |
uip_flags = UIP_CLOSE; |
|
|
1387 |
UIP_APPCALL(); |
|
|
1388 |
goto tcp_send_ack; |
|
|
1389 |
} else if(uip_flags & UIP_ACKDATA) { |
|
|
1390 |
uip_connr->tcpstateflags = FIN_WAIT_2; |
|
|
1391 |
uip_connr->len = 0; |
|
|
1392 |
goto drop; |
|
|
1393 |
} |
|
|
1394 |
if(uip_len > 0) { |
|
|
1395 |
goto tcp_send_ack; |
|
|
1396 |
} |
|
|
1397 |
goto drop; |
|
|
1398 |
|
|
|
1399 |
case FIN_WAIT_2: |
|
|
1400 |
if(uip_len > 0) { |
|
|
1401 |
uip_add_rcv_nxt(uip_len); |
|
|
1402 |
} |
|
|
1403 |
if(BUF->flags & TCP_FIN) { |
|
|
1404 |
uip_connr->tcpstateflags = TIME_WAIT; |
|
|
1405 |
uip_connr->timer = 0; |
|
|
1406 |
uip_add_rcv_nxt(1); |
|
|
1407 |
uip_flags = UIP_CLOSE; |
|
|
1408 |
UIP_APPCALL(); |
|
|
1409 |
goto tcp_send_ack; |
|
|
1410 |
} |
|
|
1411 |
if(uip_len > 0) { |
|
|
1412 |
goto tcp_send_ack; |
|
|
1413 |
} |
|
|
1414 |
goto drop; |
|
|
1415 |
|
|
|
1416 |
case TIME_WAIT: |
|
|
1417 |
goto tcp_send_ack; |
|
|
1418 |
|
|
|
1419 |
case CLOSING: |
|
|
1420 |
if(uip_flags & UIP_ACKDATA) { |
|
|
1421 |
uip_connr->tcpstateflags = TIME_WAIT; |
|
|
1422 |
uip_connr->timer = 0; |
|
|
1423 |
} |
|
|
1424 |
} |
|
|
1425 |
goto drop; |
|
|
1426 |
|
|
|
1427 |
|
|
|
1428 |
/* We jump here when we are ready to send the packet, and just want |
|
|
1429 |
to set the appropriate TCP sequence numbers in the TCP header. */ |
|
|
1430 |
tcp_send_ack: |
|
|
1431 |
BUF->flags = TCP_ACK; |
|
|
1432 |
tcp_send_nodata: |
|
|
1433 |
uip_len = 40; |
|
|
1434 |
tcp_send_noopts: |
|
|
1435 |
BUF->tcpoffset = 5 << 4; |
|
|
1436 |
tcp_send: |
|
|
1437 |
/* We're done with the input processing. We are now ready to send a |
|
|
1438 |
reply. Our job is to fill in all the fields of the TCP and IP |
|
|
1439 |
headers before calculating the checksum and finally send the |
|
|
1440 |
packet. */ |
|
|
1441 |
BUF->ackno[0] = uip_connr->rcv_nxt[0]; |
|
|
1442 |
BUF->ackno[1] = uip_connr->rcv_nxt[1]; |
|
|
1443 |
BUF->ackno[2] = uip_connr->rcv_nxt[2]; |
|
|
1444 |
BUF->ackno[3] = uip_connr->rcv_nxt[3]; |
|
|
1445 |
|
|
|
1446 |
BUF->seqno[0] = uip_connr->snd_nxt[0]; |
|
|
1447 |
BUF->seqno[1] = uip_connr->snd_nxt[1]; |
|
|
1448 |
BUF->seqno[2] = uip_connr->snd_nxt[2]; |
|
|
1449 |
BUF->seqno[3] = uip_connr->snd_nxt[3]; |
|
|
1450 |
|
|
|
1451 |
BUF->proto = UIP_PROTO_TCP; |
|
|
1452 |
|
|
|
1453 |
BUF->srcport = uip_connr->lport; |
|
|
1454 |
BUF->destport = uip_connr->rport; |
|
|
1455 |
|
|
|
1456 |
BUF->srcipaddr[0] = uip_hostaddr[0]; |
|
|
1457 |
BUF->srcipaddr[1] = uip_hostaddr[1]; |
|
|
1458 |
BUF->destipaddr[0] = uip_connr->ripaddr[0]; |
|
|
1459 |
BUF->destipaddr[1] = uip_connr->ripaddr[1]; |
|
|
1460 |
|
|
|
1461 |
|
|
|
1462 |
if(uip_connr->tcpstateflags & UIP_STOPPED) { |
|
|
1463 |
/* If the connection has issued uip_stop(), we advertise a zero |
|
|
1464 |
window so that the remote host will stop sending data. */ |
|
|
1465 |
BUF->wnd[0] = BUF->wnd[1] = 0; |
|
|
1466 |
} else { |
|
|
1467 |
BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8); |
|
|
1468 |
BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff); |
|
|
1469 |
} |
|
|
1470 |
|
|
|
1471 |
tcp_send_noconn: |
|
|
1472 |
|
|
|
1473 |
BUF->len[0] = (uip_len >> 8); |
|
|
1474 |
BUF->len[1] = (uip_len & 0xff); |
|
|
1475 |
|
|
|
1476 |
/* Calculate TCP checksum. */ |
|
|
1477 |
BUF->tcpchksum = 0; |
|
|
1478 |
BUF->tcpchksum = ~(uip_tcpchksum()); |
|
|
1479 |
|
|
|
1480 |
|
|
|
1481 |
#if UIP_UDP |
|
|
1482 |
ip_send_nolen: |
|
|
1483 |
#endif |
|
|
1484 |
|
|
|
1485 |
BUF->vhl = 0x45; |
|
|
1486 |
BUF->tos = 0; |
|
|
1487 |
BUF->ipoffset[0] = BUF->ipoffset[1] = 0; |
|
|
1488 |
BUF->ttl = UIP_TTL; |
|
|
1489 |
++ipid; |
|
|
1490 |
BUF->ipid[0] = ipid >> 8; |
|
|
1491 |
BUF->ipid[1] = ipid & 0xff; |
|
|
1492 |
|
|
|
1493 |
/* Calculate IP checksum. */ |
|
|
1494 |
BUF->ipchksum = 0; |
|
|
1495 |
BUF->ipchksum = ~(uip_ipchksum()); |
|
|
1496 |
|
|
|
1497 |
UIP_STAT(++uip_stat.tcp.sent); |
|
|
1498 |
send: |
|
|
1499 |
UIP_STAT(++uip_stat.ip.sent); |
|
|
1500 |
/* Return and let the caller do the actual transmission. */ |
|
|
1501 |
return; |
|
|
1502 |
drop: |
|
|
1503 |
uip_len = 0; |
|
|
1504 |
return; |
|
|
1505 |
} |
|
|
1506 |
/*-----------------------------------------------------------------------------------*/ |
|
|
1507 |
u16_t |
|
|
1508 |
htons(u16_t val) |
|
|
1509 |
{ |
|
|
1510 |
return HTONS(val); |
|
|
1511 |
} |
|
|
1512 |
/*-----------------------------------------------------------------------------------*/ |
|
|
1513 |
/** @} */ |