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https://github.com/oliverschmidt/contiki.git
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1931 lines
58 KiB
C
1931 lines
58 KiB
C
#define DEBUG_PRINTF(...) /*printf(__VA_ARGS__)*/
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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 1.14 2008/02/28 23:59:05 oliverschmidt Exp $
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*
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*/
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/*
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* uIP is a small implementation of the IP, UDP and TCP protocols (as
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* well as some basic ICMP stuff). The implementation couples the IP,
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* UDP, TCP and the application layers very tightly. To keep the size
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* of the compiled code down, this code frequently uses the goto
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* statement. While it would be possible to break the uip_process()
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* function into many smaller functions, this would increase the code
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* size because of the overhead of parameter passing and the fact that
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* the optimier would not be as efficient.
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*
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* The principle is that we have a small buffer, called the uip_buf,
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* in which the device driver puts an incoming packet. The TCP/IP
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* stack parses the headers in the packet, and calls the
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* application. If the remote host has sent data to the application,
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* this data is present in the uip_buf and the application read the
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* data from there. It is up to the application to put this data into
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* a byte stream if needed. The application will not be fed with data
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* that is out of sequence.
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*
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* If the application whishes to send data to the peer, it should put
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* its data into the uip_buf. The uip_appdata pointer points to the
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* first available byte. The TCP/IP stack will calculate the
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* checksums, and fill in the necessary header fields and finally send
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* the packet back to the peer.
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*/
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#include "net/uip.h"
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#include "net/uipopt.h"
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#include "net/uip_arp.h"
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#include "net/uip_arch.h"
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#if UIP_CONF_IPV6
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#include "net/uip-neighbor.h"
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#endif /* UIP_CONF_IPV6 */
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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
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setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set
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here. Otherwise, the address */
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#if UIP_FIXEDADDR > 0
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const uip_ipaddr_t uip_hostaddr =
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{ UIP_IPADDR0, UIP_IPADDR1, UIP_IPADDR2, UIP_IPADDR3 };
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const uip_ipaddr_t uip_draddr =
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{ UIP_DRIPADDR0, UIP_DRIPADDR1, UIP_DRIPADDR2, UIP_DRIPADDR3 };
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const uip_ipaddr_t uip_netmask =
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{ UIP_NETMASK0, UIP_NETMASK1, UIP_NETMASK2, UIP_NETMASK3 };
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#else
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uip_ipaddr_t uip_hostaddr, uip_draddr, uip_netmask;
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#endif /* UIP_FIXEDADDR */
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const uip_ipaddr_t uip_broadcast_addr =
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#if UIP_CONF_IPV6
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{ { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } };
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#else /* UIP_CONF_IPV6 */
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{ { 0xff, 0xff, 0xff, 0xff } };
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#endif /* UIP_CONF_IPV6 */
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const uip_ipaddr_t uip_all_zeroes_addr = { { 0x0, /* rest is 0 */ } };
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#if UIP_FIXEDETHADDR
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const struct uip_eth_addr uip_ethaddr = {{UIP_ETHADDR0,
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UIP_ETHADDR1,
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UIP_ETHADDR2,
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UIP_ETHADDR3,
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UIP_ETHADDR4,
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UIP_ETHADDR5}};
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#else
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struct uip_eth_addr uip_ethaddr = {{0,0,0,0,0,0}};
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#endif
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#ifndef UIP_CONF_EXTERNAL_BUFFER
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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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#endif /* UIP_CONF_EXTERNAL_BUFFER */
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void *uip_appdata; /* The uip_appdata pointer points to
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application data. */
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void *uip_sappdata; /* The uip_appdata pointer points to
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the application data which is to
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be sent. */
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#if UIP_URGDATA > 0
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void *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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u16_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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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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void uip_setipid(u16_t id) { ipid = id; }
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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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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 TCP_OPT_END 0 /* End of TCP options list */
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#define TCP_OPT_NOOP 1 /* "No-operation" TCP option */
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#define TCP_OPT_MSS 2 /* Maximum segment size TCP option */
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#define TCP_OPT_MSS_LEN 4 /* Length of TCP MSS option. */
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#define ICMP_ECHO_REPLY 0
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#define ICMP_ECHO 8
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#define ICMP_DEST_UNREACHABLE 3
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#define ICMP_PORT_UNREACHABLE 3
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#define ICMP6_ECHO_REPLY 129
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#define ICMP6_ECHO 128
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#define ICMP6_NEIGHBOR_SOLICITATION 135
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#define ICMP6_NEIGHBOR_ADVERTISEMENT 136
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#define ICMP6_FLAG_S (1 << 6)
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#define ICMP6_OPTION_SOURCE_LINK_ADDRESS 1
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#define ICMP6_OPTION_TARGET_LINK_ADDRESS 2
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/* Macros. */
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#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#define FBUF ((struct uip_tcpip_hdr *)&uip_reassbuf[0])
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#define ICMPBUF ((struct uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN])
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#define UDPBUF ((struct 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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#if ! UIP_ARCH_ADD32
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void
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uip_add32(u8_t *op32, u16_t op16)
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{
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uip_acc32[3] = op32[3] + (op16 & 0xff);
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uip_acc32[2] = op32[2] + (op16 >> 8);
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uip_acc32[1] = op32[1];
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uip_acc32[0] = op32[0];
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if(uip_acc32[2] < (op16 >> 8)) {
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++uip_acc32[1];
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if(uip_acc32[1] == 0) {
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++uip_acc32[0];
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}
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}
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if(uip_acc32[3] < (op16 & 0xff)) {
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++uip_acc32[2];
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if(uip_acc32[2] == 0) {
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++uip_acc32[1];
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if(uip_acc32[1] == 0) {
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++uip_acc32[0];
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}
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}
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}
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}
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#endif /* UIP_ARCH_ADD32 */
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#if ! UIP_ARCH_CHKSUM
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/*---------------------------------------------------------------------------*/
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static u16_t
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chksum(u16_t sum, const u8_t *data, u16_t len)
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{
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u16_t t;
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const u8_t *dataptr;
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const u8_t *last_byte;
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dataptr = data;
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last_byte = data + len - 1;
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while(dataptr < last_byte) { /* At least two more bytes */
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t = (dataptr[0] << 8) + dataptr[1];
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sum += t;
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if(sum < t) {
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sum++; /* carry */
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}
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dataptr += 2;
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}
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if(dataptr == last_byte) {
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t = (dataptr[0] << 8) + 0;
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sum += t;
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if(sum < t) {
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sum++; /* carry */
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}
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}
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/* Return sum in host byte order. */
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return sum;
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}
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/*---------------------------------------------------------------------------*/
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u16_t
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uip_chksum(u16_t *data, u16_t len)
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{
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return htons(chksum(0, (u8_t *)data, len));
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}
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/*---------------------------------------------------------------------------*/
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#ifndef UIP_ARCH_IPCHKSUM
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u16_t
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uip_ipchksum(void)
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{
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u16_t sum;
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sum = chksum(0, &uip_buf[UIP_LLH_LEN], UIP_IPH_LEN);
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DEBUG_PRINTF("uip_ipchksum: sum 0x%04x\n", sum);
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return (sum == 0) ? 0xffff : htons(sum);
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}
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#endif
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/*---------------------------------------------------------------------------*/
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static u16_t
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upper_layer_chksum(u8_t proto)
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{
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u16_t upper_layer_len;
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u16_t sum;
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#if UIP_CONF_IPV6
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upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]);
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#else /* UIP_CONF_IPV6 */
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upper_layer_len = (((u16_t)(BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN;
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#endif /* UIP_CONF_IPV6 */
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/* First sum pseudoheader. */
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/* IP protocol and length fields. This addition cannot carry. */
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sum = upper_layer_len + proto;
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/* Sum IP source and destination addresses. */
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sum = chksum(sum, (u8_t *)&BUF->srcipaddr, 2 * sizeof(uip_ipaddr_t));
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/* Sum TCP header and data. */
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sum = chksum(sum, &uip_buf[UIP_IPH_LEN + UIP_LLH_LEN],
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upper_layer_len);
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return (sum == 0) ? 0xffff : htons(sum);
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}
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/*---------------------------------------------------------------------------*/
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#if UIP_CONF_IPV6
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u16_t
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uip_icmp6chksum(void)
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{
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return upper_layer_chksum(UIP_PROTO_ICMP6);
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}
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#endif /* UIP_CONF_IPV6 */
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/*---------------------------------------------------------------------------*/
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u16_t
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uip_tcpchksum(void)
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{
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return upper_layer_chksum(UIP_PROTO_TCP);
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}
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/*---------------------------------------------------------------------------*/
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#if UIP_UDP_CHECKSUMS
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u16_t
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uip_udpchksum(void)
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{
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return upper_layer_chksum(UIP_PROTO_UDP);
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}
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#endif /* UIP_UDP_CHECKSUMS */
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#endif /* UIP_ARCH_CHKSUM */
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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 = UIP_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(uip_ipaddr_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 != UIP_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 == UIP_CLOSED) {
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conn = cconn;
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break;
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}
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if(cconn->tcpstateflags == UIP_TIME_WAIT) {
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if(conn == 0 ||
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cconn->timer > 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 = UIP_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; /* Initial value of the RTT variance. */
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conn->lport = htons(lastport);
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conn->rport = rport;
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uip_ipaddr_copy(&conn->ripaddr, ripaddr);
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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(const uip_ipaddr_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 == 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_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 = rport;
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if(ripaddr == NULL) {
|
|
memset(&conn->ripaddr, 0, sizeof(uip_ipaddr_t));
|
|
} else {
|
|
uip_ipaddr_copy(&conn->ripaddr, ripaddr);
|
|
}
|
|
conn->ttl = UIP_TTL;
|
|
|
|
return conn;
|
|
}
|
|
#endif /* UIP_UDP */
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
uip_unlisten(u16_t port)
|
|
{
|
|
for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
|
if(uip_listenports[c] == port) {
|
|
uip_listenports[c] = 0;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
uip_listen(u16_t port)
|
|
{
|
|
for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
|
if(uip_listenports[c] == 0) {
|
|
uip_listenports[c] = port;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/* XXX: IP fragment reassembly: not well-tested. */
|
|
|
|
#if UIP_REASSEMBLY && !UIP_CONF_IPV6
|
|
#define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
|
|
static u8_t uip_reassbuf[UIP_REASS_BUFSIZE];
|
|
static u8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
|
|
static const u8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f,
|
|
0x0f, 0x07, 0x03, 0x01};
|
|
static u16_t uip_reasslen;
|
|
static u8_t uip_reassflags;
|
|
#define UIP_REASS_FLAG_LASTFRAG 0x01
|
|
static u8_t uip_reasstmr;
|
|
|
|
#define IP_MF 0x20
|
|
|
|
static u8_t
|
|
uip_reass(void)
|
|
{
|
|
u16_t offset, len;
|
|
u16_t i;
|
|
|
|
/* If ip_reasstmr is zero, no packet is present in the buffer, so we
|
|
write the IP header of the fragment into the reassembly
|
|
buffer. The timer is updated with the maximum age. */
|
|
if(uip_reasstmr == 0) {
|
|
memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN);
|
|
uip_reasstmr = UIP_REASS_MAXAGE;
|
|
uip_reassflags = 0;
|
|
/* Clear the bitmap. */
|
|
memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap));
|
|
}
|
|
|
|
/* Check if the incoming fragment matches the one currently present
|
|
in the reasembly buffer. If so, we proceed with copying the
|
|
fragment into the buffer. */
|
|
if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] &&
|
|
BUF->srcipaddr[1] == FBUF->srcipaddr[1] &&
|
|
BUF->destipaddr[0] == FBUF->destipaddr[0] &&
|
|
BUF->destipaddr[1] == FBUF->destipaddr[1] &&
|
|
BUF->ipid[0] == FBUF->ipid[0] &&
|
|
BUF->ipid[1] == FBUF->ipid[1]) {
|
|
|
|
len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
|
|
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 ||
|
|
offset + len > UIP_REASS_BUFSIZE) {
|
|
uip_reasstmr = 0;
|
|
goto nullreturn;
|
|
}
|
|
|
|
/* Copy the fragment into the reassembly buffer, at the right
|
|
offset. */
|
|
memcpy(&uip_reassbuf[UIP_IPH_LEN + 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_REASSEMBLY */
|
|
/*---------------------------------------------------------------------------*/
|
|
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;
|
|
|
|
#if UIP_UDP
|
|
if(flag == UIP_UDP_SEND_CONN) {
|
|
goto udp_send;
|
|
}
|
|
#endif /* UIP_UDP */
|
|
|
|
uip_sappdata = uip_appdata = &uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
|
|
|
|
/* Check if we were invoked because of a poll request for a
|
|
particular connection. */
|
|
if(flag == UIP_POLL_REQUEST) {
|
|
if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED &&
|
|
!uip_outstanding(uip_connr)) {
|
|
uip_flags = UIP_POLL;
|
|
UIP_APPCALL();
|
|
goto appsend;
|
|
}
|
|
goto drop;
|
|
|
|
/* Check if we were invoked because of the perodic timer fireing. */
|
|
} else 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];
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Reset the length variables. */
|
|
uip_len = 0;
|
|
uip_slen = 0;
|
|
|
|
/* Check if the connection is in a state in which we simply wait
|
|
for the connection to time out. If so, we increase the
|
|
connection's timer and remove the connection if it times
|
|
out. */
|
|
if(uip_connr->tcpstateflags == UIP_TIME_WAIT ||
|
|
uip_connr->tcpstateflags == UIP_FIN_WAIT_2) {
|
|
++(uip_connr->timer);
|
|
if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
|
|
uip_connr->tcpstateflags = UIP_CLOSED;
|
|
}
|
|
} else if(uip_connr->tcpstateflags != UIP_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 == UIP_SYN_SENT ||
|
|
uip_connr->tcpstateflags == UIP_SYN_RCVD) &&
|
|
uip_connr->nrtx == UIP_MAXSYNRTX)) {
|
|
uip_connr->tcpstateflags = UIP_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 & UIP_TS_MASK) {
|
|
case UIP_SYN_RCVD:
|
|
/* In the SYN_RCVD state, we should retransmit our
|
|
SYNACK. */
|
|
goto tcp_send_synack;
|
|
|
|
#if UIP_ACTIVE_OPEN
|
|
case UIP_SYN_SENT:
|
|
/* In the SYN_SENT state, we retransmit out SYN. */
|
|
BUF->flags = 0;
|
|
goto tcp_send_syn;
|
|
#endif /* UIP_ACTIVE_OPEN */
|
|
|
|
case UIP_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_flags = UIP_REXMIT;
|
|
UIP_APPCALL();
|
|
goto apprexmit;
|
|
|
|
case UIP_FIN_WAIT_1:
|
|
case UIP_CLOSING:
|
|
case UIP_LAST_ACK:
|
|
/* In all these states we should retransmit a FINACK. */
|
|
goto tcp_send_finack;
|
|
|
|
}
|
|
}
|
|
} else if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) {
|
|
/* If there was no need for a retransmission, we poll the
|
|
application for new data. */
|
|
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_conn = NULL;
|
|
uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
|
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 IP input header processing code. */
|
|
|
|
#if UIP_CONF_IPV6
|
|
/* Check validity of the IP header. */
|
|
if((BUF->vtc & 0xf0) != 0x60) { /* IP version and header length. */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.vhlerr);
|
|
UIP_LOG("ipv6: invalid version.");
|
|
goto drop;
|
|
}
|
|
#else /* UIP_CONF_IPV6 */
|
|
/* 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;
|
|
}
|
|
#endif /* UIP_CONF_IPV6 */
|
|
|
|
/* Check the size of the packet. If the size reported to us in
|
|
uip_len is smaller the size reported in the IP header, we assume
|
|
that the packet has been corrupted in transit. If the size of
|
|
uip_len is larger than the size reported in the IP packet header,
|
|
the packet has been padded and we set uip_len to the correct
|
|
value.. */
|
|
|
|
if((BUF->len[0] << 8) + BUF->len[1] <= uip_len) {
|
|
uip_len = (BUF->len[0] << 8) + BUF->len[1];
|
|
#if UIP_CONF_IPV6
|
|
uip_len += 40; /* The length reported in the IPv6 header is the
|
|
length of the payload that follows the
|
|
header. However, uIP uses the uip_len variable
|
|
for holding the size of the entire packet,
|
|
including the IP header. For IPv4 this is not a
|
|
problem as the length field in the IPv4 header
|
|
contains the length of the entire packet. But
|
|
for IPv6 we need to add the size of the IPv6
|
|
header (40 bytes). */
|
|
#endif /* UIP_CONF_IPV6 */
|
|
} else {
|
|
UIP_LOG("ip: packet shorter than reported in IP header.");
|
|
goto drop;
|
|
}
|
|
|
|
#if !UIP_CONF_IPV6
|
|
/* 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_REASSEMBLY */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.fragerr);
|
|
UIP_LOG("ip: fragment dropped.");
|
|
goto drop;
|
|
#endif /* UIP_REASSEMBLY */
|
|
}
|
|
#endif /* UIP_CONF_IPV6 */
|
|
|
|
if(uip_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) {
|
|
/* 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 && !UIP_CONF_IPV6
|
|
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 */
|
|
|
|
} else {
|
|
/* If IP broadcast support is configured, we check for a broadcast
|
|
UDP packet, which may be destined to us. */
|
|
#if UIP_BROADCAST
|
|
DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum());
|
|
if(BUF->proto == UIP_PROTO_UDP &&
|
|
uip_ipaddr_cmp(&BUF->destipaddr, &uip_broadcast_addr)
|
|
/*&&
|
|
uip_ipchksum() == 0xffff*/) {
|
|
goto udp_input;
|
|
}
|
|
#endif /* UIP_BROADCAST */
|
|
|
|
/* Check if the packet is destined for our IP address. */
|
|
#if !UIP_CONF_IPV6
|
|
if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr)) {
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
goto drop;
|
|
}
|
|
#else /* UIP_CONF_IPV6 */
|
|
/* For IPv6, packet reception is a little trickier as we need to
|
|
make sure that we listen to certain multicast addresses (all
|
|
hosts multicast address, and the solicited-node multicast
|
|
address) as well. However, we will cheat here and accept all
|
|
multicast packets that are sent to the ff02::/16 addresses. */
|
|
if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr) &&
|
|
BUF->destipaddr.u16[0] != HTONS(0xff02)) {
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
goto drop;
|
|
}
|
|
#endif /* UIP_CONF_IPV6 */
|
|
}
|
|
|
|
#if !UIP_CONF_IPV6
|
|
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 /* UIP_CONF_IPV6 */
|
|
|
|
if(BUF->proto == UIP_PROTO_TCP) { /* Check for TCP packet. If so,
|
|
proceed with TCP input
|
|
processing. */
|
|
goto tcp_input;
|
|
}
|
|
|
|
#if UIP_UDP
|
|
if(BUF->proto == UIP_PROTO_UDP) {
|
|
goto udp_input;
|
|
}
|
|
#endif /* UIP_UDP */
|
|
|
|
#if !UIP_CONF_IPV6
|
|
/* ICMPv4 processing code follows. */
|
|
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_PINGADDRCONF */
|
|
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_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) {
|
|
uip_hostaddr = BUF->destipaddr;
|
|
}
|
|
#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. */
|
|
uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
|
|
UIP_STAT(++uip_stat.icmp.sent);
|
|
BUF->ttl = UIP_TTL;
|
|
goto ip_send_nolen;
|
|
|
|
/* End of IPv4 input header processing code. */
|
|
#else /* !UIP_CONF_IPV6 */
|
|
|
|
/* This is IPv6 ICMPv6 processing code. */
|
|
DEBUG_PRINTF("icmp6_input: length %d\n", uip_len);
|
|
|
|
if(BUF->proto != UIP_PROTO_ICMP6) { /* We only allow ICMPv6 packets from
|
|
here. */
|
|
UIP_STAT(++uip_stat.ip.drop);
|
|
UIP_STAT(++uip_stat.ip.protoerr);
|
|
UIP_LOG("ip: neither tcp nor icmp6.");
|
|
goto drop;
|
|
}
|
|
|
|
UIP_STAT(++uip_stat.icmp.recv);
|
|
|
|
/* If we get a neighbor solicitation for our address we should send
|
|
a neighbor advertisement message back. */
|
|
if(ICMPBUF->type == ICMP6_NEIGHBOR_SOLICITATION) {
|
|
if(uip_ipaddr_cmp(&ICMPBUF->icmp6data, &uip_hostaddr)) {
|
|
|
|
if(ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS) {
|
|
/* Save the sender's address in our neighbor list. */
|
|
uip_neighbor_add(&ICMPBUF->srcipaddr, &(ICMPBUF->options[2]));
|
|
}
|
|
|
|
/* We should now send a neighbor advertisement back to where the
|
|
neighbor solicication came from. */
|
|
ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT;
|
|
ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */
|
|
|
|
ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0;
|
|
|
|
uip_ipaddr_copy(&ICMPBUF->destipaddr, &ICMPBUF->srcipaddr);
|
|
uip_ipaddr_copy(&ICMPBUF->srcipaddr, &uip_hostaddr);
|
|
ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS;
|
|
ICMPBUF->options[1] = 1; /* Options length, 1 = 8 bytes. */
|
|
memcpy(&(ICMPBUF->options[2]), &uip_ethaddr, sizeof(uip_ethaddr));
|
|
ICMPBUF->icmpchksum = 0;
|
|
ICMPBUF->icmpchksum = ~uip_icmp6chksum();
|
|
|
|
goto send;
|
|
|
|
}
|
|
goto drop;
|
|
} else if(ICMPBUF->type == ICMP6_ECHO) {
|
|
/* ICMP echo (i.e., ping) processing. This is simple, we only
|
|
change the ICMP type from ECHO to ECHO_REPLY and update the
|
|
ICMP checksum before we return the packet. */
|
|
|
|
ICMPBUF->type = ICMP6_ECHO_REPLY;
|
|
|
|
uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
ICMPBUF->icmpchksum = 0;
|
|
ICMPBUF->icmpchksum = ~uip_icmp6chksum();
|
|
|
|
UIP_STAT(++uip_stat.icmp.sent);
|
|
goto send;
|
|
} else {
|
|
DEBUG_PRINTF("Unknown icmp6 message type %d\n", ICMPBUF->type);
|
|
UIP_STAT(++uip_stat.icmp.drop);
|
|
UIP_STAT(++uip_stat.icmp.typeerr);
|
|
UIP_LOG("icmp: unknown ICMP message.");
|
|
goto drop;
|
|
}
|
|
|
|
/* End of IPv6 ICMP processing. */
|
|
|
|
#endif /* !UIP_CONF_IPV6 */
|
|
|
|
#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
|
|
uip_len = uip_len - UIP_IPUDPH_LEN;
|
|
uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
|
if(UDPBUF->udpchksum != 0 && uip_udpchksum() != 0xffff) {
|
|
UIP_STAT(++uip_stat.udp.drop);
|
|
UIP_STAT(++uip_stat.udp.chkerr);
|
|
UIP_LOG("udp: bad checksum.");
|
|
goto drop;
|
|
}
|
|
#else /* UIP_UDP_CHECKSUMS */
|
|
uip_len = uip_len - UIP_IPUDPH_LEN;
|
|
#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 the local UDP port is non-zero, the connection is considered
|
|
to be used. If so, the local port number is checked against the
|
|
destination port number in the received packet. If the two port
|
|
numbers match, the remote port number is checked if the
|
|
connection is bound to a remote port. Finally, if the
|
|
connection is bound to a remote IP address, the source IP
|
|
address of the packet is checked. */
|
|
if(uip_udp_conn->lport != 0 &&
|
|
UDPBUF->destport == uip_udp_conn->lport &&
|
|
(uip_udp_conn->rport == 0 ||
|
|
UDPBUF->srcport == uip_udp_conn->rport) &&
|
|
(uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_all_zeroes_addr) ||
|
|
uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_broadcast_addr) ||
|
|
uip_ipaddr_cmp(&BUF->srcipaddr, &uip_udp_conn->ripaddr))) {
|
|
goto udp_found;
|
|
}
|
|
}
|
|
UIP_LOG("udp: no matching connection found");
|
|
#if UIP_CONF_ICMP_DEST_UNREACH && !UIP_CONF_IPV6
|
|
/* Copy fields from packet header into payload of this ICMP packet. */
|
|
memcpy(&(ICMPBUF->payload[0]), ICMPBUF, UIP_IPH_LEN + 8);
|
|
|
|
/* Set the ICMP type and code. */
|
|
ICMPBUF->type = ICMP_DEST_UNREACHABLE;
|
|
ICMPBUF->icode = ICMP_PORT_UNREACHABLE;
|
|
|
|
/* Calculate the ICMP checksum. */
|
|
ICMPBUF->icmpchksum = 0;
|
|
ICMPBUF->icmpchksum = ~uip_chksum((u16_t *)&(ICMPBUF->type), 36);
|
|
|
|
/* Set the IP destination address to be the source address of the
|
|
original packet. */
|
|
uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
|
|
|
/* Set our IP address as the source address. */
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
|
|
/* The size of the ICMP destination unreachable packet is 36 + the
|
|
size of the IP header (20) = 56. */
|
|
uip_len = 36 + UIP_IPH_LEN;
|
|
ICMPBUF->len[0] = 0;
|
|
ICMPBUF->len[1] = (u8_t)uip_len;
|
|
ICMPBUF->ttl = UIP_TTL;
|
|
ICMPBUF->proto = UIP_PROTO_ICMP;
|
|
|
|
goto ip_send_nolen;
|
|
#else /* UIP_CONF_ICMP_DEST_UNREACH */
|
|
goto drop;
|
|
#endif /* UIP_CONF_ICMP_DEST_UNREACH */
|
|
|
|
udp_found:
|
|
uip_conn = NULL;
|
|
uip_flags = UIP_NEWDATA;
|
|
uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
|
uip_slen = 0;
|
|
UIP_UDP_APPCALL();
|
|
|
|
udp_send:
|
|
if(uip_slen == 0) {
|
|
goto drop;
|
|
}
|
|
uip_len = uip_slen + UIP_IPUDPH_LEN;
|
|
|
|
#if UIP_CONF_IPV6
|
|
/* For IPv6, the IP length field does not include the IPv6 IP header
|
|
length. */
|
|
BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
|
|
BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
|
|
#else /* UIP_CONF_IPV6 */
|
|
BUF->len[0] = (uip_len >> 8);
|
|
BUF->len[1] = (uip_len & 0xff);
|
|
#endif /* UIP_CONF_IPV6 */
|
|
|
|
BUF->ttl = uip_udp_conn->ttl;
|
|
BUF->proto = UIP_PROTO_UDP;
|
|
|
|
UDPBUF->udplen = HTONS(uip_slen + UIP_UDPH_LEN);
|
|
UDPBUF->udpchksum = 0;
|
|
|
|
BUF->srcport = uip_udp_conn->lport;
|
|
BUF->destport = uip_udp_conn->rport;
|
|
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
uip_ipaddr_copy(&BUF->destipaddr, &uip_udp_conn->ripaddr);
|
|
|
|
uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN];
|
|
|
|
#if UIP_UDP_CHECKSUMS
|
|
/* Calculate UDP checksum. */
|
|
UDPBUF->udpchksum = ~(uip_udpchksum());
|
|
if(UDPBUF->udpchksum == 0) {
|
|
UDPBUF->udpchksum = 0xffff;
|
|
}
|
|
#endif /* UIP_UDP_CHECKSUMS */
|
|
|
|
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(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;
|
|
}
|
|
|
|
/* Demultiplex this segment. */
|
|
/* First check any active connections. */
|
|
for(uip_connr = &uip_conns[0]; uip_connr <= &uip_conns[UIP_CONNS - 1];
|
|
++uip_connr) {
|
|
if(uip_connr->tcpstateflags != UIP_CLOSED &&
|
|
BUF->destport == uip_connr->lport &&
|
|
BUF->srcport == uip_connr->rport &&
|
|
uip_ipaddr_cmp(&BUF->srcipaddr, &uip_connr->ripaddr)) {
|
|
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 = UIP_IPTCPH_LEN;
|
|
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. */
|
|
uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
|
|
/* 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 == UIP_CLOSED) {
|
|
uip_connr = &uip_conns[c];
|
|
break;
|
|
}
|
|
if(uip_conns[c].tcpstateflags == UIP_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_ipaddr_copy(&uip_connr->ripaddr, &BUF->srcipaddr);
|
|
uip_connr->tcpstateflags = UIP_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 == TCP_OPT_END) {
|
|
/* End of options. */
|
|
break;
|
|
} else if(opt == TCP_OPT_NOOP) {
|
|
++c;
|
|
/* NOP option. */
|
|
} else if(opt == TCP_OPT_MSS &&
|
|
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
|
|
/* 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[UIP_IPTCPH_LEN + 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] = TCP_OPT_MSS;
|
|
BUF->optdata[1] = TCP_OPT_MSS_LEN;
|
|
BUF->optdata[2] = (UIP_TCP_MSS) / 256;
|
|
BUF->optdata[3] = (UIP_TCP_MSS) & 255;
|
|
uip_len = UIP_IPTCPH_LEN + TCP_OPT_MSS_LEN;
|
|
BUF->tcpoffset = ((UIP_TCPH_LEN + TCP_OPT_MSS_LEN) / 4) << 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 = UIP_CLOSED;
|
|
UIP_LOG("tcp: got reset, aborting connection.");
|
|
uip_flags = UIP_ABORT;
|
|
UIP_APPCALL();
|
|
goto drop;
|
|
}
|
|
/* Calculate 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 - UIP_IPH_LEN;
|
|
|
|
/* 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_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) &&
|
|
((BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)))) {
|
|
if((uip_len > 0 || ((BUF->flags & (TCP_SYN | TCP_FIN)) != 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;
|
|
|
|
/* Reset length of outstanding data. */
|
|
uip_connr->len = 0;
|
|
}
|
|
|
|
}
|
|
|
|
/* Do different things depending on in what state the connection is. */
|
|
switch(uip_connr->tcpstateflags & UIP_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 UIP_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 = UIP_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 UIP_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_CTL) == (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[UIP_IPTCPH_LEN + UIP_LLH_LEN + c];
|
|
if(opt == TCP_OPT_END) {
|
|
/* End of options. */
|
|
break;
|
|
} else if(opt == TCP_OPT_NOOP) {
|
|
++c;
|
|
/* NOP option. */
|
|
} else if(opt == TCP_OPT_MSS &&
|
|
uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
|
|
/* 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 = UIP_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;
|
|
}
|
|
/* Inform the application that the connection failed */
|
|
uip_flags = UIP_ABORT;
|
|
UIP_APPCALL();
|
|
/* The connection is closed after we send the RST */
|
|
uip_conn->tcpstateflags = UIP_CLOSED;
|
|
goto reset;
|
|
#endif /* UIP_ACTIVE_OPEN */
|
|
|
|
case UIP_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 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
|
|
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 = UIP_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) != 0) {
|
|
#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;
|
|
#else /* UIP_URGDATA > 0 */
|
|
uip_appdata = ((char *)uip_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]);
|
|
uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
|
|
#endif /* UIP_URGDATA > 0 */
|
|
}
|
|
|
|
/* 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 UIP_IPTCPH_LEN + UIP_LLH_LEN
|
|
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 = UIP_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 = UIP_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;
|
|
}
|
|
}
|
|
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 UIP_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 = UIP_CLOSED;
|
|
uip_flags = UIP_CLOSE;
|
|
UIP_APPCALL();
|
|
}
|
|
break;
|
|
|
|
case UIP_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 = UIP_TIME_WAIT;
|
|
uip_connr->timer = 0;
|
|
uip_connr->len = 0;
|
|
} else {
|
|
uip_connr->tcpstateflags = UIP_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 = UIP_FIN_WAIT_2;
|
|
uip_connr->len = 0;
|
|
goto drop;
|
|
}
|
|
if(uip_len > 0) {
|
|
goto tcp_send_ack;
|
|
}
|
|
goto drop;
|
|
|
|
case UIP_FIN_WAIT_2:
|
|
if(uip_len > 0) {
|
|
uip_add_rcv_nxt(uip_len);
|
|
}
|
|
if(BUF->flags & TCP_FIN) {
|
|
uip_connr->tcpstateflags = UIP_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 UIP_TIME_WAIT:
|
|
goto tcp_send_ack;
|
|
|
|
case UIP_CLOSING:
|
|
if(uip_flags & UIP_ACKDATA) {
|
|
uip_connr->tcpstateflags = UIP_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 = UIP_IPTCPH_LEN;
|
|
|
|
tcp_send_noopts:
|
|
BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 4;
|
|
|
|
/* 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. */
|
|
tcp_send:
|
|
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;
|
|
|
|
uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
|
uip_ipaddr_copy(&BUF->destipaddr, &uip_connr->ripaddr);
|
|
|
|
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->ttl = UIP_TTL;
|
|
#if UIP_CONF_IPV6
|
|
/* For IPv6, the IP length field does not include the IPv6 IP header
|
|
length. */
|
|
BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
|
|
BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
|
|
#else /* UIP_CONF_IPV6 */
|
|
BUF->len[0] = (uip_len >> 8);
|
|
BUF->len[1] = (uip_len & 0xff);
|
|
#endif /* UIP_CONF_IPV6 */
|
|
|
|
BUF->urgp[0] = BUF->urgp[1] = 0;
|
|
|
|
/* Calculate TCP checksum. */
|
|
BUF->tcpchksum = 0;
|
|
BUF->tcpchksum = ~(uip_tcpchksum());
|
|
|
|
ip_send_nolen:
|
|
#if UIP_CONF_IPV6
|
|
BUF->vtc = 0x60;
|
|
BUF->tcflow = 0x00;
|
|
BUF->flow = 0x00;
|
|
#else /* UIP_CONF_IPV6 */
|
|
BUF->vhl = 0x45;
|
|
BUF->tos = 0;
|
|
BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
|
|
++ipid;
|
|
BUF->ipid[0] = ipid >> 8;
|
|
BUF->ipid[1] = ipid & 0xff;
|
|
/* Calculate IP checksum. */
|
|
BUF->ipchksum = 0;
|
|
BUF->ipchksum = ~(uip_ipchksum());
|
|
DEBUG_PRINTF("uip ip_send_nolen: chkecum 0x%04x\n", uip_ipchksum());
|
|
#endif /* UIP_CONF_IPV6 */
|
|
UIP_STAT(++uip_stat.tcp.sent);
|
|
#if UIP_CONF_IPV6
|
|
send:
|
|
#endif /* UIP_CONF_IPV6 */
|
|
DEBUG_PRINTF("Sending packet with length %d (%d)\n", uip_len,
|
|
(BUF->len[0] << 8) | BUF->len[1]);
|
|
|
|
UIP_STAT(++uip_stat.ip.sent);
|
|
/* Return and let the caller do the actual transmission. */
|
|
uip_flags = 0;
|
|
return;
|
|
|
|
drop:
|
|
uip_len = 0;
|
|
uip_flags = 0;
|
|
return;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
u16_t
|
|
htons(u16_t val)
|
|
{
|
|
return HTONS(val);
|
|
}
|
|
|
|
u32_t
|
|
htonl(u32_t val)
|
|
{
|
|
return HTONL(val);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
uip_send(const void *data, int len)
|
|
{
|
|
int copylen;
|
|
#define MIN(a,b) ((a) < (b)? (a): (b))
|
|
copylen = MIN(len, UIP_BUFSIZE - UIP_LLH_LEN - UIP_TCPIP_HLEN -
|
|
(int)((char *)uip_sappdata - (char *)&uip_buf[UIP_LLH_LEN + UIP_TCPIP_HLEN]));
|
|
if(copylen > 0) {
|
|
uip_slen = copylen;
|
|
if(data != uip_sappdata) {
|
|
memcpy(uip_sappdata, (data), uip_slen);
|
|
}
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/** @} */
|