[101] | 1 | #define DEBUG_PRINTF(...) /*printf(__VA_ARGS__)*/
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| 2 |
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| 3 | /**
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| 4 | * \defgroup uip The uIP TCP/IP stack
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| 5 | * @{
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| 6 | *
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| 7 | * uIP is an implementation of the TCP/IP protocol stack intended for
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| 8 | * small 8-bit and 16-bit microcontrollers.
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| 9 | *
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| 10 | * uIP provides the necessary protocols for Internet communication,
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| 11 | * with a very small code footprint and RAM requirements - the uIP
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| 12 | * code size is on the order of a few kilobytes and RAM usage is on
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| 13 | * the order of a few hundred bytes.
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| 14 | */
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| 15 |
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| 16 | /**
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| 17 | * \file
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| 18 | * The uIP TCP/IP stack code.
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| 19 | * \author Adam Dunkels <adam@dunkels.com>
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| 20 | */
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| 21 |
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| 22 | /*
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| 23 | * Copyright (c) 2001-2003, Adam Dunkels.
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| 24 | * All rights reserved.
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| 25 | *
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| 26 | * Redistribution and use in source and binary forms, with or without
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| 27 | * modification, are permitted provided that the following conditions
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| 28 | * are met:
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| 29 | * 1. Redistributions of source code must retain the above copyright
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| 30 | * notice, this list of conditions and the following disclaimer.
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| 31 | * 2. Redistributions in binary form must reproduce the above copyright
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| 32 | * notice, this list of conditions and the following disclaimer in the
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| 33 | * documentation and/or other materials provided with the distribution.
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| 34 | * 3. The name of the author may not be used to endorse or promote
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| 35 | * products derived from this software without specific prior
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| 36 | * written permission.
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| 37 | *
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| 38 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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| 39 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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| 40 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 41 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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| 42 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 43 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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| 44 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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| 45 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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| 46 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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| 47 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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| 48 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 49 | *
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| 50 | * This file is part of the uIP TCP/IP stack.
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| 51 | *
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| 52 | * $Id: uip.c 262 2016-11-18 05:58:30Z coas-nagasima $
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| 53 | *
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| 54 | */
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| 55 |
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| 56 | /*
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| 57 | * uIP is a small implementation of the IP, UDP and TCP protocols (as
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| 58 | * well as some basic ICMP stuff). The implementation couples the IP,
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| 59 | * UDP, TCP and the application layers very tightly. To keep the size
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| 60 | * of the compiled code down, this code frequently uses the goto
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| 61 | * statement. While it would be possible to break the uip_process()
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| 62 | * function into many smaller functions, this would increase the code
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| 63 | * size because of the overhead of parameter passing and the fact that
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| 64 | * the optimier would not be as efficient.
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| 65 | *
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| 66 | * The principle is that we have a small buffer, called the uip_buf,
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| 67 | * in which the device driver puts an incoming packet. The TCP/IP
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| 68 | * stack parses the headers in the packet, and calls the
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| 69 | * application. If the remote host has sent data to the application,
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| 70 | * this data is present in the uip_buf and the application read the
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| 71 | * data from there. It is up to the application to put this data into
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| 72 | * a byte stream if needed. The application will not be fed with data
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| 73 | * that is out of sequence.
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| 74 | *
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| 75 | * If the application whishes to send data to the peer, it should put
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| 76 | * its data into the uip_buf. The uip_appdata pointer points to the
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| 77 | * first available byte. The TCP/IP stack will calculate the
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| 78 | * checksums, and fill in the necessary header fields and finally send
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| 79 | * the packet back to the peer.
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| 80 | */
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| 81 |
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[158] | 82 | #include "net/ip/uip.h"
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| 83 | #include "net/ip/uipopt.h"
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| 84 | #include "net/ip/uip_arch.h"
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[101] | 85 |
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| 86 | #if UIP_CONF_IPV6
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[158] | 87 | #include "net/ipv4/uip-neighbor.h"
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[101] | 88 | #endif /* UIP_CONF_IPV6 */
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| 89 |
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| 90 | #include <string.h>
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| 91 |
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| 92 | /*---------------------------------------------------------------------------*/
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| 93 | /* Variable definitions. */
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| 94 |
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| 95 |
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| 96 | /* The IP address of this host. If it is defined to be fixed (by
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| 97 | setting UIP_FIXEDADDR to 1 in uipopt.h), the address is set
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| 98 | here. Otherwise, the address */
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| 99 | #if UIP_FIXEDADDR > 0
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| 100 | const uip_ipaddr_t uip_hostaddr =
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[262] | 101 | { UIP_IPADDR0, UIP_IPADDR1, UIP_IPADDR2, UIP_IPADDR3 };
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[101] | 102 | const uip_ipaddr_t uip_draddr =
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[262] | 103 | { UIP_DRIPADDR0, UIP_DRIPADDR1, UIP_DRIPADDR2, UIP_DRIPADDR3 };
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[101] | 104 | const uip_ipaddr_t uip_netmask =
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[262] | 105 | { UIP_NETMASK0, UIP_NETMASK1, UIP_NETMASK2, UIP_NETMASK3 };
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[101] | 106 | #else
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| 107 | uip_ipaddr_t uip_hostaddr, uip_draddr, uip_netmask;
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| 108 | #endif /* UIP_FIXEDADDR */
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| 109 |
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[262] | 110 | const uip_ipaddr_t uip_broadcast_addr =
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[101] | 111 | #if UIP_CONF_IPV6
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[262] | 112 | { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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| 113 | 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff } };
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[101] | 114 | #else /* UIP_CONF_IPV6 */
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[262] | 115 | { { 0xff, 0xff, 0xff, 0xff } };
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[101] | 116 | #endif /* UIP_CONF_IPV6 */
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[262] | 117 | const uip_ipaddr_t uip_all_zeroes_addr = { { 0x0, /* rest is 0 */ } };
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[101] | 118 |
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| 119 | #if UIP_FIXEDETHADDR
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[262] | 120 | const struct uip_eth_addr uip_lladdr = {{UIP_ETHADDR0,
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[101] | 121 | UIP_ETHADDR1,
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| 122 | UIP_ETHADDR2,
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| 123 | UIP_ETHADDR3,
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| 124 | UIP_ETHADDR4,
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| 125 | UIP_ETHADDR5}};
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| 126 | #else
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[262] | 127 | struct uip_eth_addr uip_lladdr = {{0,0,0,0,0,0}};
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[101] | 128 | #endif
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| 129 |
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| 130 | #ifndef UIP_CONF_EXTERNAL_BUFFER
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[158] | 131 | uint8_t uip_buf[UIP_BUFSIZE + 2]; /* The packet buffer that contains
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[101] | 132 | incoming packets. */
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| 133 | #endif /* UIP_CONF_EXTERNAL_BUFFER */
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| 134 |
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| 135 | void *uip_appdata; /* The uip_appdata pointer points to
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| 136 | application data. */
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| 137 | void *uip_sappdata; /* The uip_appdata pointer points to
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| 138 | the application data which is to
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| 139 | be sent. */
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| 140 | #if UIP_URGDATA > 0
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| 141 | void *uip_urgdata; /* The uip_urgdata pointer points to
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| 142 | urgent data (out-of-band data), if
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| 143 | present. */
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[158] | 144 | uint16_t uip_urglen, uip_surglen;
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[101] | 145 | #endif /* UIP_URGDATA > 0 */
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| 146 |
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[158] | 147 | uint16_t uip_len, uip_slen;
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[101] | 148 | /* The uip_len is either 8 or 16 bits,
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| 149 | depending on the maximum packet
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| 150 | size. */
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| 151 |
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[158] | 152 | uint8_t uip_flags; /* The uip_flags variable is used for
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[101] | 153 | communication between the TCP/IP stack
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| 154 | and the application program. */
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| 155 | struct uip_conn *uip_conn; /* uip_conn always points to the current
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| 156 | connection. */
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| 157 |
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| 158 | struct uip_conn uip_conns[UIP_CONNS];
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| 159 | /* The uip_conns array holds all TCP
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| 160 | connections. */
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[158] | 161 | uint16_t uip_listenports[UIP_LISTENPORTS];
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[101] | 162 | /* The uip_listenports list all currently
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| 163 | listning ports. */
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| 164 | #if UIP_UDP
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| 165 | struct uip_udp_conn *uip_udp_conn;
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| 166 | struct uip_udp_conn uip_udp_conns[UIP_UDP_CONNS];
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| 167 | #endif /* UIP_UDP */
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| 168 |
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[158] | 169 | static uint16_t ipid; /* Ths ipid variable is an increasing
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[101] | 170 | number that is used for the IP ID
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| 171 | field. */
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| 172 |
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[158] | 173 | void uip_setipid(uint16_t id) { ipid = id; }
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[101] | 174 |
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[158] | 175 | static uint8_t iss[4]; /* The iss variable is used for the TCP
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[101] | 176 | initial sequence number. */
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| 177 |
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| 178 | #if UIP_ACTIVE_OPEN
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[158] | 179 | static uint16_t lastport; /* Keeps track of the last port used for
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[101] | 180 | a new connection. */
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| 181 | #endif /* UIP_ACTIVE_OPEN */
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| 182 |
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| 183 | /* Temporary variables. */
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[158] | 184 | uint8_t uip_acc32[4];
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| 185 | static uint8_t c, opt;
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| 186 | static uint16_t tmp16;
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[101] | 187 |
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| 188 | /* Structures and definitions. */
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| 189 | #define TCP_FIN 0x01
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| 190 | #define TCP_SYN 0x02
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| 191 | #define TCP_RST 0x04
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| 192 | #define TCP_PSH 0x08
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| 193 | #define TCP_ACK 0x10
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| 194 | #define TCP_URG 0x20
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| 195 | #define TCP_CTL 0x3f
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| 196 |
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| 197 | #define TCP_OPT_END 0 /* End of TCP options list */
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| 198 | #define TCP_OPT_NOOP 1 /* "No-operation" TCP option */
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| 199 | #define TCP_OPT_MSS 2 /* Maximum segment size TCP option */
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| 200 |
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| 201 | #define TCP_OPT_MSS_LEN 4 /* Length of TCP MSS option. */
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| 202 |
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| 203 | #define ICMP_ECHO_REPLY 0
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| 204 | #define ICMP_ECHO 8
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| 205 |
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| 206 | #define ICMP6_ECHO_REPLY 129
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| 207 | #define ICMP6_ECHO 128
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| 208 | #define ICMP6_NEIGHBOR_SOLICITATION 135
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| 209 | #define ICMP6_NEIGHBOR_ADVERTISEMENT 136
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| 210 |
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| 211 | #define ICMP6_FLAG_S (1 << 6)
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| 212 |
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| 213 | #define ICMP6_OPTION_SOURCE_LINK_ADDRESS 1
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| 214 | #define ICMP6_OPTION_TARGET_LINK_ADDRESS 2
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| 215 |
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| 216 |
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| 217 | /* Macros. */
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| 218 | #define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
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| 219 | #define FBUF ((struct uip_tcpip_hdr *)&uip_reassbuf[0])
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| 220 | #define ICMPBUF ((struct uip_icmpip_hdr *)&uip_buf[UIP_LLH_LEN])
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| 221 | #define UDPBUF ((struct uip_udpip_hdr *)&uip_buf[UIP_LLH_LEN])
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| 222 |
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| 223 |
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| 224 | #if UIP_STATISTICS == 1
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| 225 | struct uip_stats uip_stat;
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| 226 | #define UIP_STAT(s) s
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| 227 | #else
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| 228 | #define UIP_STAT(s)
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| 229 | #endif /* UIP_STATISTICS == 1 */
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| 230 |
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| 231 | #if UIP_LOGGING == 1
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| 232 | #include <stdio.h>
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| 233 | void uip_log(char *msg);
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| 234 | #define UIP_LOG(m) uip_log(m)
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| 235 | #else
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| 236 | #define UIP_LOG(m)
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| 237 | #endif /* UIP_LOGGING == 1 */
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| 238 |
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| 239 | #if ! UIP_ARCH_ADD32
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| 240 | void
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[158] | 241 | uip_add32(uint8_t *op32, uint16_t op16)
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[101] | 242 | {
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| 243 | uip_acc32[3] = op32[3] + (op16 & 0xff);
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| 244 | uip_acc32[2] = op32[2] + (op16 >> 8);
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| 245 | uip_acc32[1] = op32[1];
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| 246 | uip_acc32[0] = op32[0];
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| 247 |
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| 248 | if(uip_acc32[2] < (op16 >> 8)) {
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| 249 | ++uip_acc32[1];
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| 250 | if(uip_acc32[1] == 0) {
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| 251 | ++uip_acc32[0];
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| 252 | }
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| 253 | }
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| 254 |
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| 255 |
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| 256 | if(uip_acc32[3] < (op16 & 0xff)) {
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| 257 | ++uip_acc32[2];
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| 258 | if(uip_acc32[2] == 0) {
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| 259 | ++uip_acc32[1];
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| 260 | if(uip_acc32[1] == 0) {
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| 261 | ++uip_acc32[0];
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| 262 | }
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| 263 | }
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| 264 | }
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| 265 | }
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| 266 |
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| 267 | #endif /* UIP_ARCH_ADD32 */
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| 268 |
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| 269 | #if ! UIP_ARCH_CHKSUM
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| 270 | /*---------------------------------------------------------------------------*/
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[158] | 271 | static uint16_t
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| 272 | chksum(uint16_t sum, const uint8_t *data, uint16_t len)
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[101] | 273 | {
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[158] | 274 | uint16_t t;
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| 275 | const uint8_t *dataptr;
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| 276 | const uint8_t *last_byte;
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[101] | 277 |
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| 278 | dataptr = data;
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| 279 | last_byte = data + len - 1;
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| 280 |
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| 281 | while(dataptr < last_byte) { /* At least two more bytes */
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| 282 | t = (dataptr[0] << 8) + dataptr[1];
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| 283 | sum += t;
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| 284 | if(sum < t) {
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| 285 | sum++; /* carry */
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| 286 | }
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| 287 | dataptr += 2;
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| 288 | }
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| 289 |
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| 290 | if(dataptr == last_byte) {
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| 291 | t = (dataptr[0] << 8) + 0;
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| 292 | sum += t;
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| 293 | if(sum < t) {
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| 294 | sum++; /* carry */
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| 295 | }
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| 296 | }
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| 297 |
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| 298 | /* Return sum in host byte order. */
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| 299 | return sum;
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| 300 | }
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| 301 | /*---------------------------------------------------------------------------*/
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[158] | 302 | uint16_t
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| 303 | uip_chksum(uint16_t *data, uint16_t len)
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[101] | 304 | {
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[262] | 305 | return uip_htons(chksum(0, (uint8_t *)data, len));
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[101] | 306 | }
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| 307 | /*---------------------------------------------------------------------------*/
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| 308 | #ifndef UIP_ARCH_IPCHKSUM
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[158] | 309 | uint16_t
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[101] | 310 | uip_ipchksum(void)
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| 311 | {
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[158] | 312 | uint16_t sum;
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[101] | 313 |
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| 314 | sum = chksum(0, &uip_buf[UIP_LLH_LEN], UIP_IPH_LEN);
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| 315 | DEBUG_PRINTF("uip_ipchksum: sum 0x%04x\n", sum);
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[262] | 316 | return (sum == 0) ? 0xffff : uip_htons(sum);
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[101] | 317 | }
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| 318 | #endif
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| 319 | /*---------------------------------------------------------------------------*/
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[158] | 320 | static uint16_t
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| 321 | upper_layer_chksum(uint8_t proto)
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[101] | 322 | {
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[158] | 323 | uint16_t upper_layer_len;
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| 324 | uint16_t sum;
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[101] | 325 |
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| 326 | #if UIP_CONF_IPV6
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[158] | 327 | upper_layer_len = (((uint16_t)(BUF->len[0]) << 8) + BUF->len[1]);
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[101] | 328 | #else /* UIP_CONF_IPV6 */
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[158] | 329 | upper_layer_len = (((uint16_t)(BUF->len[0]) << 8) + BUF->len[1]) - UIP_IPH_LEN;
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[101] | 330 | #endif /* UIP_CONF_IPV6 */
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| 331 |
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| 332 | /* First sum pseudoheader. */
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| 333 |
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| 334 | /* IP protocol and length fields. This addition cannot carry. */
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| 335 | sum = upper_layer_len + proto;
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| 336 | /* Sum IP source and destination addresses. */
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[262] | 337 | sum = chksum(sum, (uint8_t *)&BUF->srcipaddr, 2 * sizeof(uip_ipaddr_t));
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[101] | 338 |
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| 339 | /* Sum TCP header and data. */
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| 340 | sum = chksum(sum, &uip_buf[UIP_IPH_LEN + UIP_LLH_LEN],
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| 341 | upper_layer_len);
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| 342 |
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[262] | 343 | return (sum == 0) ? 0xffff : uip_htons(sum);
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[101] | 344 | }
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| 345 | /*---------------------------------------------------------------------------*/
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| 346 | #if UIP_CONF_IPV6
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[158] | 347 | uint16_t
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[101] | 348 | uip_icmp6chksum(void)
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| 349 | {
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| 350 | return upper_layer_chksum(UIP_PROTO_ICMP6);
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| 351 |
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| 352 | }
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| 353 | #endif /* UIP_CONF_IPV6 */
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| 354 | /*---------------------------------------------------------------------------*/
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[158] | 355 | uint16_t
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[101] | 356 | uip_tcpchksum(void)
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| 357 | {
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| 358 | return upper_layer_chksum(UIP_PROTO_TCP);
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| 359 | }
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| 360 | /*---------------------------------------------------------------------------*/
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| 361 | #if UIP_UDP_CHECKSUMS
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[158] | 362 | uint16_t
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[101] | 363 | uip_udpchksum(void)
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| 364 | {
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| 365 | return upper_layer_chksum(UIP_PROTO_UDP);
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| 366 | }
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| 367 | #endif /* UIP_UDP_CHECKSUMS */
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| 368 | #endif /* UIP_ARCH_CHKSUM */
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| 369 | /*---------------------------------------------------------------------------*/
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| 370 | void
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| 371 | uip_init(void)
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| 372 | {
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| 373 | for(c = 0; c < UIP_LISTENPORTS; ++c) {
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| 374 | uip_listenports[c] = 0;
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| 375 | }
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| 376 | for(c = 0; c < UIP_CONNS; ++c) {
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| 377 | uip_conns[c].tcpstateflags = UIP_CLOSED;
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| 378 | }
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| 379 | #if UIP_ACTIVE_OPEN
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| 380 | lastport = 1024;
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| 381 | #endif /* UIP_ACTIVE_OPEN */
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| 382 |
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| 383 | #if UIP_UDP
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| 384 | for(c = 0; c < UIP_UDP_CONNS; ++c) {
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| 385 | uip_udp_conns[c].lport = 0;
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| 386 | }
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| 387 | #endif /* UIP_UDP */
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| 388 |
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| 389 |
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| 390 | /* IPv4 initialization. */
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| 391 | #if UIP_FIXEDADDR == 0
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| 392 | /* uip_hostaddr[0] = uip_hostaddr[1] = 0;*/
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| 393 | #endif /* UIP_FIXEDADDR */
|
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| 394 |
|
---|
| 395 | }
|
---|
| 396 | /*---------------------------------------------------------------------------*/
|
---|
| 397 | #if UIP_ACTIVE_OPEN
|
---|
| 398 | struct uip_conn *
|
---|
[158] | 399 | uip_connect(uip_ipaddr_t *ripaddr, uint16_t rport)
|
---|
[101] | 400 | {
|
---|
| 401 | register struct uip_conn *conn, *cconn;
|
---|
| 402 |
|
---|
| 403 | /* Find an unused local port. */
|
---|
| 404 | again:
|
---|
| 405 | ++lastport;
|
---|
| 406 |
|
---|
| 407 | if(lastport >= 32000) {
|
---|
| 408 | lastport = 4096;
|
---|
| 409 | }
|
---|
| 410 |
|
---|
| 411 | /* Check if this port is already in use, and if so try to find
|
---|
| 412 | another one. */
|
---|
| 413 | for(c = 0; c < UIP_CONNS; ++c) {
|
---|
| 414 | conn = &uip_conns[c];
|
---|
| 415 | if(conn->tcpstateflags != UIP_CLOSED &&
|
---|
[262] | 416 | conn->lport == uip_htons(lastport)) {
|
---|
[101] | 417 | goto again;
|
---|
| 418 | }
|
---|
| 419 | }
|
---|
| 420 |
|
---|
| 421 | conn = 0;
|
---|
| 422 | for(c = 0; c < UIP_CONNS; ++c) {
|
---|
| 423 | cconn = &uip_conns[c];
|
---|
| 424 | if(cconn->tcpstateflags == UIP_CLOSED) {
|
---|
| 425 | conn = cconn;
|
---|
| 426 | break;
|
---|
| 427 | }
|
---|
| 428 | if(cconn->tcpstateflags == UIP_TIME_WAIT) {
|
---|
| 429 | if(conn == 0 ||
|
---|
| 430 | cconn->timer > conn->timer) {
|
---|
| 431 | conn = cconn;
|
---|
| 432 | }
|
---|
| 433 | }
|
---|
| 434 | }
|
---|
| 435 |
|
---|
| 436 | if(conn == 0) {
|
---|
| 437 | return 0;
|
---|
| 438 | }
|
---|
| 439 |
|
---|
| 440 | conn->tcpstateflags = UIP_SYN_SENT;
|
---|
| 441 |
|
---|
| 442 | conn->snd_nxt[0] = iss[0];
|
---|
| 443 | conn->snd_nxt[1] = iss[1];
|
---|
| 444 | conn->snd_nxt[2] = iss[2];
|
---|
| 445 | conn->snd_nxt[3] = iss[3];
|
---|
| 446 |
|
---|
| 447 | conn->initialmss = conn->mss = UIP_TCP_MSS;
|
---|
| 448 |
|
---|
| 449 | conn->len = 1; /* TCP length of the SYN is one. */
|
---|
| 450 | conn->nrtx = 0;
|
---|
| 451 | conn->timer = 1; /* Send the SYN next time around. */
|
---|
| 452 | conn->rto = UIP_RTO;
|
---|
| 453 | conn->sa = 0;
|
---|
| 454 | conn->sv = 16; /* Initial value of the RTT variance. */
|
---|
[262] | 455 | conn->lport = uip_htons(lastport);
|
---|
[101] | 456 | conn->rport = rport;
|
---|
| 457 | uip_ipaddr_copy(&conn->ripaddr, ripaddr);
|
---|
| 458 |
|
---|
| 459 | return conn;
|
---|
| 460 | }
|
---|
| 461 | #endif /* UIP_ACTIVE_OPEN */
|
---|
| 462 | /*---------------------------------------------------------------------------*/
|
---|
| 463 | #if UIP_UDP
|
---|
| 464 | struct uip_udp_conn *
|
---|
[262] | 465 | uip_udp_new(const uip_ipaddr_t *ripaddr, uint16_t rport)
|
---|
[101] | 466 | {
|
---|
| 467 | register struct uip_udp_conn *conn;
|
---|
| 468 |
|
---|
| 469 | /* Find an unused local port. */
|
---|
| 470 | again:
|
---|
| 471 | ++lastport;
|
---|
| 472 |
|
---|
| 473 | if(lastport >= 32000) {
|
---|
| 474 | lastport = 4096;
|
---|
| 475 | }
|
---|
| 476 |
|
---|
| 477 | for(c = 0; c < UIP_UDP_CONNS; ++c) {
|
---|
[262] | 478 | if(uip_udp_conns[c].lport == uip_htons(lastport)) {
|
---|
[101] | 479 | goto again;
|
---|
| 480 | }
|
---|
| 481 | }
|
---|
| 482 |
|
---|
| 483 |
|
---|
| 484 | conn = 0;
|
---|
| 485 | for(c = 0; c < UIP_UDP_CONNS; ++c) {
|
---|
| 486 | if(uip_udp_conns[c].lport == 0) {
|
---|
| 487 | conn = &uip_udp_conns[c];
|
---|
| 488 | break;
|
---|
| 489 | }
|
---|
| 490 | }
|
---|
| 491 |
|
---|
| 492 | if(conn == 0) {
|
---|
| 493 | return 0;
|
---|
| 494 | }
|
---|
| 495 |
|
---|
[262] | 496 | conn->lport = UIP_HTONS(lastport);
|
---|
[101] | 497 | conn->rport = rport;
|
---|
| 498 | if(ripaddr == NULL) {
|
---|
[262] | 499 | memset(&conn->ripaddr, 0, sizeof(uip_ipaddr_t));
|
---|
[101] | 500 | } else {
|
---|
| 501 | uip_ipaddr_copy(&conn->ripaddr, ripaddr);
|
---|
| 502 | }
|
---|
| 503 | conn->ttl = UIP_TTL;
|
---|
| 504 |
|
---|
| 505 | return conn;
|
---|
| 506 | }
|
---|
| 507 | #endif /* UIP_UDP */
|
---|
| 508 | /*---------------------------------------------------------------------------*/
|
---|
| 509 | void
|
---|
[158] | 510 | uip_unlisten(uint16_t port)
|
---|
[101] | 511 | {
|
---|
| 512 | for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
---|
| 513 | if(uip_listenports[c] == port) {
|
---|
| 514 | uip_listenports[c] = 0;
|
---|
| 515 | return;
|
---|
| 516 | }
|
---|
| 517 | }
|
---|
| 518 | }
|
---|
| 519 | /*---------------------------------------------------------------------------*/
|
---|
| 520 | void
|
---|
[158] | 521 | uip_listen(uint16_t port)
|
---|
[101] | 522 | {
|
---|
| 523 | for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
---|
| 524 | if(uip_listenports[c] == 0) {
|
---|
| 525 | uip_listenports[c] = port;
|
---|
| 526 | return;
|
---|
| 527 | }
|
---|
| 528 | }
|
---|
| 529 | }
|
---|
| 530 | /*---------------------------------------------------------------------------*/
|
---|
| 531 | /* XXX: IP fragment reassembly: not well-tested. */
|
---|
| 532 |
|
---|
| 533 | #if UIP_REASSEMBLY && !UIP_CONF_IPV6
|
---|
| 534 | #define UIP_REASS_BUFSIZE (UIP_BUFSIZE - UIP_LLH_LEN)
|
---|
[158] | 535 | static uint8_t uip_reassbuf[UIP_REASS_BUFSIZE];
|
---|
| 536 | static uint8_t uip_reassbitmap[UIP_REASS_BUFSIZE / (8 * 8)];
|
---|
| 537 | static const uint8_t bitmap_bits[8] = {0xff, 0x7f, 0x3f, 0x1f,
|
---|
[101] | 538 | 0x0f, 0x07, 0x03, 0x01};
|
---|
[158] | 539 | static uint16_t uip_reasslen;
|
---|
| 540 | static uint8_t uip_reassflags;
|
---|
[101] | 541 | #define UIP_REASS_FLAG_LASTFRAG 0x01
|
---|
[158] | 542 | static uint8_t uip_reasstmr;
|
---|
[101] | 543 |
|
---|
| 544 | #define IP_MF 0x20
|
---|
| 545 |
|
---|
[158] | 546 | static uint8_t
|
---|
[101] | 547 | uip_reass(void)
|
---|
| 548 | {
|
---|
[158] | 549 | uint16_t offset, len;
|
---|
| 550 | uint16_t i;
|
---|
[101] | 551 |
|
---|
| 552 | /* If ip_reasstmr is zero, no packet is present in the buffer, so we
|
---|
| 553 | write the IP header of the fragment into the reassembly
|
---|
| 554 | buffer. The timer is updated with the maximum age. */
|
---|
| 555 | if(uip_reasstmr == 0) {
|
---|
| 556 | memcpy(uip_reassbuf, &BUF->vhl, UIP_IPH_LEN);
|
---|
| 557 | uip_reasstmr = UIP_REASS_MAXAGE;
|
---|
| 558 | uip_reassflags = 0;
|
---|
| 559 | /* Clear the bitmap. */
|
---|
| 560 | memset(uip_reassbitmap, 0, sizeof(uip_reassbitmap));
|
---|
| 561 | }
|
---|
| 562 |
|
---|
| 563 | /* Check if the incoming fragment matches the one currently present
|
---|
| 564 | in the reasembly buffer. If so, we proceed with copying the
|
---|
| 565 | fragment into the buffer. */
|
---|
| 566 | if(BUF->srcipaddr[0] == FBUF->srcipaddr[0] &&
|
---|
| 567 | BUF->srcipaddr[1] == FBUF->srcipaddr[1] &&
|
---|
| 568 | BUF->destipaddr[0] == FBUF->destipaddr[0] &&
|
---|
| 569 | BUF->destipaddr[1] == FBUF->destipaddr[1] &&
|
---|
| 570 | BUF->ipid[0] == FBUF->ipid[0] &&
|
---|
| 571 | BUF->ipid[1] == FBUF->ipid[1]) {
|
---|
| 572 |
|
---|
| 573 | len = (BUF->len[0] << 8) + BUF->len[1] - (BUF->vhl & 0x0f) * 4;
|
---|
| 574 | offset = (((BUF->ipoffset[0] & 0x3f) << 8) + BUF->ipoffset[1]) * 8;
|
---|
| 575 |
|
---|
| 576 | /* If the offset or the offset + fragment length overflows the
|
---|
| 577 | reassembly buffer, we discard the entire packet. */
|
---|
| 578 | if(offset > UIP_REASS_BUFSIZE ||
|
---|
| 579 | offset + len > UIP_REASS_BUFSIZE) {
|
---|
| 580 | uip_reasstmr = 0;
|
---|
| 581 | goto nullreturn;
|
---|
| 582 | }
|
---|
| 583 |
|
---|
| 584 | /* Copy the fragment into the reassembly buffer, at the right
|
---|
| 585 | offset. */
|
---|
| 586 | memcpy(&uip_reassbuf[UIP_IPH_LEN + offset],
|
---|
| 587 | (char *)BUF + (int)((BUF->vhl & 0x0f) * 4),
|
---|
| 588 | len);
|
---|
| 589 |
|
---|
| 590 | /* Update the bitmap. */
|
---|
| 591 | if(offset / (8 * 8) == (offset + len) / (8 * 8)) {
|
---|
| 592 | /* If the two endpoints are in the same byte, we only update
|
---|
| 593 | that byte. */
|
---|
| 594 |
|
---|
| 595 | uip_reassbitmap[offset / (8 * 8)] |=
|
---|
| 596 | bitmap_bits[(offset / 8 ) & 7] &
|
---|
| 597 | ~bitmap_bits[((offset + len) / 8 ) & 7];
|
---|
| 598 | } else {
|
---|
| 599 | /* If the two endpoints are in different bytes, we update the
|
---|
| 600 | bytes in the endpoints and fill the stuff inbetween with
|
---|
| 601 | 0xff. */
|
---|
| 602 | uip_reassbitmap[offset / (8 * 8)] |=
|
---|
| 603 | bitmap_bits[(offset / 8 ) & 7];
|
---|
| 604 | for(i = 1 + offset / (8 * 8); i < (offset + len) / (8 * 8); ++i) {
|
---|
| 605 | uip_reassbitmap[i] = 0xff;
|
---|
| 606 | }
|
---|
| 607 | uip_reassbitmap[(offset + len) / (8 * 8)] |=
|
---|
| 608 | ~bitmap_bits[((offset + len) / 8 ) & 7];
|
---|
| 609 | }
|
---|
| 610 |
|
---|
| 611 | /* If this fragment has the More Fragments flag set to zero, we
|
---|
| 612 | know that this is the last fragment, so we can calculate the
|
---|
| 613 | size of the entire packet. We also set the
|
---|
| 614 | IP_REASS_FLAG_LASTFRAG flag to indicate that we have received
|
---|
| 615 | the final fragment. */
|
---|
| 616 |
|
---|
| 617 | if((BUF->ipoffset[0] & IP_MF) == 0) {
|
---|
| 618 | uip_reassflags |= UIP_REASS_FLAG_LASTFRAG;
|
---|
| 619 | uip_reasslen = offset + len;
|
---|
| 620 | }
|
---|
| 621 |
|
---|
| 622 | /* Finally, we check if we have a full packet in the buffer. We do
|
---|
| 623 | this by checking if we have the last fragment and if all bits
|
---|
| 624 | in the bitmap are set. */
|
---|
| 625 | if(uip_reassflags & UIP_REASS_FLAG_LASTFRAG) {
|
---|
| 626 | /* Check all bytes up to and including all but the last byte in
|
---|
| 627 | the bitmap. */
|
---|
| 628 | for(i = 0; i < uip_reasslen / (8 * 8) - 1; ++i) {
|
---|
| 629 | if(uip_reassbitmap[i] != 0xff) {
|
---|
| 630 | goto nullreturn;
|
---|
| 631 | }
|
---|
| 632 | }
|
---|
| 633 | /* Check the last byte in the bitmap. It should contain just the
|
---|
| 634 | right amount of bits. */
|
---|
| 635 | if(uip_reassbitmap[uip_reasslen / (8 * 8)] !=
|
---|
[158] | 636 | (uint8_t)~bitmap_bits[uip_reasslen / 8 & 7]) {
|
---|
[101] | 637 | goto nullreturn;
|
---|
| 638 | }
|
---|
| 639 |
|
---|
| 640 | /* If we have come this far, we have a full packet in the
|
---|
| 641 | buffer, so we allocate a pbuf and copy the packet into it. We
|
---|
| 642 | also reset the timer. */
|
---|
| 643 | uip_reasstmr = 0;
|
---|
| 644 | memcpy(BUF, FBUF, uip_reasslen);
|
---|
| 645 |
|
---|
| 646 | /* Pretend to be a "normal" (i.e., not fragmented) IP packet
|
---|
| 647 | from now on. */
|
---|
| 648 | BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
|
---|
| 649 | BUF->len[0] = uip_reasslen >> 8;
|
---|
| 650 | BUF->len[1] = uip_reasslen & 0xff;
|
---|
| 651 | BUF->ipchksum = 0;
|
---|
| 652 | BUF->ipchksum = ~(uip_ipchksum());
|
---|
| 653 |
|
---|
| 654 | return uip_reasslen;
|
---|
| 655 | }
|
---|
| 656 | }
|
---|
| 657 |
|
---|
| 658 | nullreturn:
|
---|
| 659 | return 0;
|
---|
| 660 | }
|
---|
| 661 | #endif /* UIP_REASSEMBLY */
|
---|
| 662 | /*---------------------------------------------------------------------------*/
|
---|
| 663 | static void
|
---|
[158] | 664 | uip_add_rcv_nxt(uint16_t n)
|
---|
[101] | 665 | {
|
---|
| 666 | uip_add32(uip_conn->rcv_nxt, n);
|
---|
| 667 | uip_conn->rcv_nxt[0] = uip_acc32[0];
|
---|
| 668 | uip_conn->rcv_nxt[1] = uip_acc32[1];
|
---|
| 669 | uip_conn->rcv_nxt[2] = uip_acc32[2];
|
---|
| 670 | uip_conn->rcv_nxt[3] = uip_acc32[3];
|
---|
| 671 | }
|
---|
| 672 | /*---------------------------------------------------------------------------*/
|
---|
| 673 | void
|
---|
[158] | 674 | uip_process(uint8_t flag)
|
---|
[101] | 675 | {
|
---|
| 676 | register struct uip_conn *uip_connr = uip_conn;
|
---|
| 677 |
|
---|
| 678 | #if UIP_UDP
|
---|
| 679 | if(flag == UIP_UDP_SEND_CONN) {
|
---|
| 680 | goto udp_send;
|
---|
| 681 | }
|
---|
| 682 | #endif /* UIP_UDP */
|
---|
| 683 |
|
---|
| 684 | uip_sappdata = uip_appdata = &uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN];
|
---|
| 685 |
|
---|
| 686 | /* Check if we were invoked because of a poll request for a
|
---|
| 687 | particular connection. */
|
---|
| 688 | if(flag == UIP_POLL_REQUEST) {
|
---|
| 689 | if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED &&
|
---|
| 690 | !uip_outstanding(uip_connr)) {
|
---|
| 691 | uip_flags = UIP_POLL;
|
---|
| 692 | UIP_APPCALL();
|
---|
| 693 | goto appsend;
|
---|
| 694 | }
|
---|
| 695 | goto drop;
|
---|
| 696 |
|
---|
| 697 | /* Check if we were invoked because of the perodic timer fireing. */
|
---|
| 698 | } else if(flag == UIP_TIMER) {
|
---|
| 699 | #if UIP_REASSEMBLY
|
---|
| 700 | if(uip_reasstmr != 0) {
|
---|
| 701 | --uip_reasstmr;
|
---|
| 702 | }
|
---|
| 703 | #endif /* UIP_REASSEMBLY */
|
---|
| 704 | /* Increase the initial sequence number. */
|
---|
| 705 | if(++iss[3] == 0) {
|
---|
| 706 | if(++iss[2] == 0) {
|
---|
| 707 | if(++iss[1] == 0) {
|
---|
| 708 | ++iss[0];
|
---|
| 709 | }
|
---|
| 710 | }
|
---|
| 711 | }
|
---|
| 712 |
|
---|
| 713 | /* Reset the length variables. */
|
---|
| 714 | uip_len = 0;
|
---|
| 715 | uip_slen = 0;
|
---|
| 716 |
|
---|
| 717 | /* Check if the connection is in a state in which we simply wait
|
---|
| 718 | for the connection to time out. If so, we increase the
|
---|
| 719 | connection's timer and remove the connection if it times
|
---|
| 720 | out. */
|
---|
| 721 | if(uip_connr->tcpstateflags == UIP_TIME_WAIT ||
|
---|
| 722 | uip_connr->tcpstateflags == UIP_FIN_WAIT_2) {
|
---|
| 723 | ++(uip_connr->timer);
|
---|
| 724 | if(uip_connr->timer == UIP_TIME_WAIT_TIMEOUT) {
|
---|
| 725 | uip_connr->tcpstateflags = UIP_CLOSED;
|
---|
| 726 | }
|
---|
| 727 | } else if(uip_connr->tcpstateflags != UIP_CLOSED) {
|
---|
| 728 | /* If the connection has outstanding data, we increase the
|
---|
| 729 | connection's timer and see if it has reached the RTO value
|
---|
| 730 | in which case we retransmit. */
|
---|
[262] | 731 |
|
---|
[101] | 732 | if(uip_outstanding(uip_connr)) {
|
---|
| 733 | if(uip_connr->timer-- == 0) {
|
---|
| 734 | if(uip_connr->nrtx == UIP_MAXRTX ||
|
---|
| 735 | ((uip_connr->tcpstateflags == UIP_SYN_SENT ||
|
---|
| 736 | uip_connr->tcpstateflags == UIP_SYN_RCVD) &&
|
---|
| 737 | uip_connr->nrtx == UIP_MAXSYNRTX)) {
|
---|
| 738 | uip_connr->tcpstateflags = UIP_CLOSED;
|
---|
| 739 |
|
---|
| 740 | /* We call UIP_APPCALL() with uip_flags set to
|
---|
| 741 | UIP_TIMEDOUT to inform the application that the
|
---|
| 742 | connection has timed out. */
|
---|
| 743 | uip_flags = UIP_TIMEDOUT;
|
---|
| 744 | UIP_APPCALL();
|
---|
| 745 |
|
---|
| 746 | /* We also send a reset packet to the remote host. */
|
---|
| 747 | BUF->flags = TCP_RST | TCP_ACK;
|
---|
| 748 | goto tcp_send_nodata;
|
---|
| 749 | }
|
---|
| 750 |
|
---|
| 751 | /* Exponential backoff. */
|
---|
| 752 | uip_connr->timer = UIP_RTO << (uip_connr->nrtx > 4?
|
---|
| 753 | 4:
|
---|
| 754 | uip_connr->nrtx);
|
---|
| 755 | ++(uip_connr->nrtx);
|
---|
| 756 |
|
---|
| 757 | /* Ok, so we need to retransmit. We do this differently
|
---|
| 758 | depending on which state we are in. In ESTABLISHED, we
|
---|
| 759 | call upon the application so that it may prepare the
|
---|
| 760 | data for the retransmit. In SYN_RCVD, we resend the
|
---|
| 761 | SYNACK that we sent earlier and in LAST_ACK we have to
|
---|
| 762 | retransmit our FINACK. */
|
---|
| 763 | UIP_STAT(++uip_stat.tcp.rexmit);
|
---|
| 764 | switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
|
---|
| 765 | case UIP_SYN_RCVD:
|
---|
| 766 | /* In the SYN_RCVD state, we should retransmit our
|
---|
| 767 | SYNACK. */
|
---|
| 768 | goto tcp_send_synack;
|
---|
| 769 |
|
---|
| 770 | #if UIP_ACTIVE_OPEN
|
---|
| 771 | case UIP_SYN_SENT:
|
---|
| 772 | /* In the SYN_SENT state, we retransmit out SYN. */
|
---|
| 773 | BUF->flags = 0;
|
---|
| 774 | goto tcp_send_syn;
|
---|
| 775 | #endif /* UIP_ACTIVE_OPEN */
|
---|
| 776 |
|
---|
| 777 | case UIP_ESTABLISHED:
|
---|
| 778 | /* In the ESTABLISHED state, we call upon the application
|
---|
| 779 | to do the actual retransmit after which we jump into
|
---|
| 780 | the code for sending out the packet (the apprexmit
|
---|
| 781 | label). */
|
---|
| 782 | uip_flags = UIP_REXMIT;
|
---|
| 783 | UIP_APPCALL();
|
---|
| 784 | goto apprexmit;
|
---|
| 785 |
|
---|
| 786 | case UIP_FIN_WAIT_1:
|
---|
| 787 | case UIP_CLOSING:
|
---|
| 788 | case UIP_LAST_ACK:
|
---|
| 789 | /* In all these states we should retransmit a FINACK. */
|
---|
| 790 | goto tcp_send_finack;
|
---|
| 791 |
|
---|
| 792 | }
|
---|
| 793 | }
|
---|
| 794 | } else if((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_ESTABLISHED) {
|
---|
| 795 | /* If there was no need for a retransmission, we poll the
|
---|
| 796 | application for new data. */
|
---|
| 797 | uip_flags = UIP_POLL;
|
---|
| 798 | UIP_APPCALL();
|
---|
| 799 | goto appsend;
|
---|
| 800 | }
|
---|
| 801 | }
|
---|
| 802 | goto drop;
|
---|
| 803 | }
|
---|
| 804 | #if UIP_UDP
|
---|
| 805 | if(flag == UIP_UDP_TIMER) {
|
---|
| 806 | if(uip_udp_conn->lport != 0) {
|
---|
| 807 | uip_conn = NULL;
|
---|
| 808 | uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
---|
| 809 | uip_len = uip_slen = 0;
|
---|
| 810 | uip_flags = UIP_POLL;
|
---|
| 811 | UIP_UDP_APPCALL();
|
---|
| 812 | goto udp_send;
|
---|
| 813 | } else {
|
---|
| 814 | goto drop;
|
---|
| 815 | }
|
---|
| 816 | }
|
---|
| 817 | #endif
|
---|
| 818 |
|
---|
| 819 | /* This is where the input processing starts. */
|
---|
| 820 | UIP_STAT(++uip_stat.ip.recv);
|
---|
| 821 |
|
---|
| 822 | /* Start of IP input header processing code. */
|
---|
| 823 |
|
---|
| 824 | #if UIP_CONF_IPV6
|
---|
| 825 | /* Check validity of the IP header. */
|
---|
| 826 | if((BUF->vtc & 0xf0) != 0x60) { /* IP version and header length. */
|
---|
| 827 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 828 | UIP_STAT(++uip_stat.ip.vhlerr);
|
---|
| 829 | UIP_LOG("ipv6: invalid version.");
|
---|
| 830 | goto drop;
|
---|
| 831 | }
|
---|
| 832 | #else /* UIP_CONF_IPV6 */
|
---|
| 833 | /* Check validity of the IP header. */
|
---|
| 834 | if(BUF->vhl != 0x45) { /* IP version and header length. */
|
---|
| 835 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 836 | UIP_STAT(++uip_stat.ip.vhlerr);
|
---|
| 837 | UIP_LOG("ip: invalid version or header length.");
|
---|
| 838 | goto drop;
|
---|
| 839 | }
|
---|
| 840 | #endif /* UIP_CONF_IPV6 */
|
---|
| 841 |
|
---|
| 842 | /* Check the size of the packet. If the size reported to us in
|
---|
| 843 | uip_len is smaller the size reported in the IP header, we assume
|
---|
| 844 | that the packet has been corrupted in transit. If the size of
|
---|
| 845 | uip_len is larger than the size reported in the IP packet header,
|
---|
| 846 | the packet has been padded and we set uip_len to the correct
|
---|
| 847 | value.. */
|
---|
| 848 |
|
---|
| 849 | if((BUF->len[0] << 8) + BUF->len[1] <= uip_len) {
|
---|
| 850 | uip_len = (BUF->len[0] << 8) + BUF->len[1];
|
---|
| 851 | #if UIP_CONF_IPV6
|
---|
| 852 | uip_len += 40; /* The length reported in the IPv6 header is the
|
---|
| 853 | length of the payload that follows the
|
---|
| 854 | header. However, uIP uses the uip_len variable
|
---|
| 855 | for holding the size of the entire packet,
|
---|
| 856 | including the IP header. For IPv4 this is not a
|
---|
| 857 | problem as the length field in the IPv4 header
|
---|
| 858 | contains the length of the entire packet. But
|
---|
| 859 | for IPv6 we need to add the size of the IPv6
|
---|
| 860 | header (40 bytes). */
|
---|
| 861 | #endif /* UIP_CONF_IPV6 */
|
---|
| 862 | } else {
|
---|
| 863 | UIP_LOG("ip: packet shorter than reported in IP header.");
|
---|
| 864 | goto drop;
|
---|
| 865 | }
|
---|
| 866 |
|
---|
| 867 | #if !UIP_CONF_IPV6
|
---|
| 868 | /* Check the fragment flag. */
|
---|
| 869 | if((BUF->ipoffset[0] & 0x3f) != 0 ||
|
---|
| 870 | BUF->ipoffset[1] != 0) {
|
---|
| 871 | #if UIP_REASSEMBLY
|
---|
| 872 | uip_len = uip_reass();
|
---|
| 873 | if(uip_len == 0) {
|
---|
| 874 | goto drop;
|
---|
| 875 | }
|
---|
| 876 | #else /* UIP_REASSEMBLY */
|
---|
| 877 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 878 | UIP_STAT(++uip_stat.ip.fragerr);
|
---|
| 879 | UIP_LOG("ip: fragment dropped.");
|
---|
| 880 | goto drop;
|
---|
| 881 | #endif /* UIP_REASSEMBLY */
|
---|
| 882 | }
|
---|
| 883 | #endif /* UIP_CONF_IPV6 */
|
---|
| 884 |
|
---|
[262] | 885 | if(uip_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) {
|
---|
[101] | 886 | /* If we are configured to use ping IP address configuration and
|
---|
| 887 | hasn't been assigned an IP address yet, we accept all ICMP
|
---|
| 888 | packets. */
|
---|
| 889 | #if UIP_PINGADDRCONF && !UIP_CONF_IPV6
|
---|
| 890 | if(BUF->proto == UIP_PROTO_ICMP) {
|
---|
| 891 | UIP_LOG("ip: possible ping config packet received.");
|
---|
| 892 | goto icmp_input;
|
---|
| 893 | } else {
|
---|
| 894 | UIP_LOG("ip: packet dropped since no address assigned.");
|
---|
| 895 | goto drop;
|
---|
| 896 | }
|
---|
| 897 | #endif /* UIP_PINGADDRCONF */
|
---|
| 898 |
|
---|
| 899 | } else {
|
---|
| 900 | /* If IP broadcast support is configured, we check for a broadcast
|
---|
| 901 | UDP packet, which may be destined to us. */
|
---|
| 902 | #if UIP_BROADCAST
|
---|
| 903 | DEBUG_PRINTF("UDP IP checksum 0x%04x\n", uip_ipchksum());
|
---|
| 904 | if(BUF->proto == UIP_PROTO_UDP &&
|
---|
[262] | 905 | (uip_ipaddr_cmp(&BUF->destipaddr, &uip_broadcast_addr) ||
|
---|
| 906 | (BUF->destipaddr.u8[0] & 224) == 224)) { /* XXX this is a
|
---|
| 907 | hack to be able
|
---|
| 908 | to receive UDP
|
---|
| 909 | multicast
|
---|
| 910 | packets. We check
|
---|
| 911 | for the bit
|
---|
| 912 | pattern of the
|
---|
| 913 | multicast
|
---|
| 914 | prefix. */
|
---|
[101] | 915 | goto udp_input;
|
---|
| 916 | }
|
---|
| 917 | #endif /* UIP_BROADCAST */
|
---|
| 918 |
|
---|
| 919 | /* Check if the packet is destined for our IP address. */
|
---|
| 920 | #if !UIP_CONF_IPV6
|
---|
[262] | 921 | if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr)) {
|
---|
[101] | 922 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 923 | goto drop;
|
---|
| 924 | }
|
---|
| 925 | #else /* UIP_CONF_IPV6 */
|
---|
| 926 | /* For IPv6, packet reception is a little trickier as we need to
|
---|
| 927 | make sure that we listen to certain multicast addresses (all
|
---|
| 928 | hosts multicast address, and the solicited-node multicast
|
---|
| 929 | address) as well. However, we will cheat here and accept all
|
---|
| 930 | multicast packets that are sent to the ff02::/16 addresses. */
|
---|
[262] | 931 | if(!uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr) &&
|
---|
| 932 | BUF->destipaddr.u16[0] != UIP_HTONS(0xff02)) {
|
---|
[101] | 933 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 934 | goto drop;
|
---|
| 935 | }
|
---|
| 936 | #endif /* UIP_CONF_IPV6 */
|
---|
| 937 | }
|
---|
| 938 |
|
---|
| 939 | #if !UIP_CONF_IPV6
|
---|
| 940 | if(uip_ipchksum() != 0xffff) { /* Compute and check the IP header
|
---|
| 941 | checksum. */
|
---|
| 942 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 943 | UIP_STAT(++uip_stat.ip.chkerr);
|
---|
| 944 | UIP_LOG("ip: bad checksum.");
|
---|
| 945 | goto drop;
|
---|
| 946 | }
|
---|
| 947 | #endif /* UIP_CONF_IPV6 */
|
---|
| 948 |
|
---|
| 949 | if(BUF->proto == UIP_PROTO_TCP) { /* Check for TCP packet. If so,
|
---|
| 950 | proceed with TCP input
|
---|
| 951 | processing. */
|
---|
| 952 | goto tcp_input;
|
---|
| 953 | }
|
---|
| 954 |
|
---|
| 955 | #if UIP_UDP
|
---|
| 956 | if(BUF->proto == UIP_PROTO_UDP) {
|
---|
| 957 | goto udp_input;
|
---|
| 958 | }
|
---|
| 959 | #endif /* UIP_UDP */
|
---|
| 960 |
|
---|
| 961 | #if !UIP_CONF_IPV6
|
---|
| 962 | /* ICMPv4 processing code follows. */
|
---|
| 963 | if(BUF->proto != UIP_PROTO_ICMP) { /* We only allow ICMP packets from
|
---|
| 964 | here. */
|
---|
| 965 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 966 | UIP_STAT(++uip_stat.ip.protoerr);
|
---|
| 967 | UIP_LOG("ip: neither tcp nor icmp.");
|
---|
| 968 | goto drop;
|
---|
| 969 | }
|
---|
| 970 |
|
---|
| 971 | #if UIP_PINGADDRCONF
|
---|
| 972 | icmp_input:
|
---|
| 973 | #endif /* UIP_PINGADDRCONF */
|
---|
| 974 | UIP_STAT(++uip_stat.icmp.recv);
|
---|
| 975 |
|
---|
| 976 | /* ICMP echo (i.e., ping) processing. This is simple, we only change
|
---|
| 977 | the ICMP type from ECHO to ECHO_REPLY and adjust the ICMP
|
---|
| 978 | checksum before we return the packet. */
|
---|
| 979 | if(ICMPBUF->type != ICMP_ECHO) {
|
---|
| 980 | UIP_STAT(++uip_stat.icmp.drop);
|
---|
| 981 | UIP_STAT(++uip_stat.icmp.typeerr);
|
---|
| 982 | UIP_LOG("icmp: not icmp echo.");
|
---|
| 983 | goto drop;
|
---|
| 984 | }
|
---|
| 985 |
|
---|
| 986 | /* If we are configured to use ping IP address assignment, we use
|
---|
| 987 | the destination IP address of this ping packet and assign it to
|
---|
| 988 | ourself. */
|
---|
| 989 | #if UIP_PINGADDRCONF
|
---|
[262] | 990 | if(uip_ipaddr_cmp(&uip_hostaddr, &uip_all_zeroes_addr)) {
|
---|
| 991 | uip_hostaddr = BUF->destipaddr;
|
---|
[101] | 992 | }
|
---|
| 993 | #endif /* UIP_PINGADDRCONF */
|
---|
| 994 |
|
---|
| 995 | ICMPBUF->type = ICMP_ECHO_REPLY;
|
---|
| 996 |
|
---|
[262] | 997 | if(ICMPBUF->icmpchksum >= UIP_HTONS(0xffff - (ICMP_ECHO << 8))) {
|
---|
| 998 | ICMPBUF->icmpchksum += UIP_HTONS(ICMP_ECHO << 8) + 1;
|
---|
[101] | 999 | } else {
|
---|
[262] | 1000 | ICMPBUF->icmpchksum += UIP_HTONS(ICMP_ECHO << 8);
|
---|
[101] | 1001 | }
|
---|
| 1002 |
|
---|
| 1003 | /* Swap IP addresses. */
|
---|
[262] | 1004 | uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
---|
| 1005 | uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
---|
[101] | 1006 |
|
---|
| 1007 | UIP_STAT(++uip_stat.icmp.sent);
|
---|
[262] | 1008 | BUF->ttl = UIP_TTL;
|
---|
| 1009 | goto ip_send_nolen;
|
---|
[101] | 1010 |
|
---|
| 1011 | /* End of IPv4 input header processing code. */
|
---|
| 1012 | #else /* !UIP_CONF_IPV6 */
|
---|
| 1013 |
|
---|
| 1014 | /* This is IPv6 ICMPv6 processing code. */
|
---|
| 1015 | DEBUG_PRINTF("icmp6_input: length %d\n", uip_len);
|
---|
| 1016 |
|
---|
| 1017 | if(BUF->proto != UIP_PROTO_ICMP6) { /* We only allow ICMPv6 packets from
|
---|
| 1018 | here. */
|
---|
| 1019 | UIP_STAT(++uip_stat.ip.drop);
|
---|
| 1020 | UIP_STAT(++uip_stat.ip.protoerr);
|
---|
| 1021 | UIP_LOG("ip: neither tcp nor icmp6.");
|
---|
| 1022 | goto drop;
|
---|
| 1023 | }
|
---|
| 1024 |
|
---|
| 1025 | UIP_STAT(++uip_stat.icmp.recv);
|
---|
| 1026 |
|
---|
| 1027 | /* If we get a neighbor solicitation for our address we should send
|
---|
| 1028 | a neighbor advertisement message back. */
|
---|
| 1029 | if(ICMPBUF->type == ICMP6_NEIGHBOR_SOLICITATION) {
|
---|
[262] | 1030 | if(uip_ipaddr_cmp(&ICMPBUF->icmp6data, &uip_hostaddr)) {
|
---|
[101] | 1031 |
|
---|
| 1032 | if(ICMPBUF->options[0] == ICMP6_OPTION_SOURCE_LINK_ADDRESS) {
|
---|
| 1033 | /* Save the sender's address in our neighbor list. */
|
---|
[262] | 1034 | uip_neighbor_add(&ICMPBUF->srcipaddr, &(ICMPBUF->options[2]));
|
---|
[101] | 1035 | }
|
---|
| 1036 |
|
---|
| 1037 | /* We should now send a neighbor advertisement back to where the
|
---|
| 1038 | neighbor solicication came from. */
|
---|
| 1039 | ICMPBUF->type = ICMP6_NEIGHBOR_ADVERTISEMENT;
|
---|
| 1040 | ICMPBUF->flags = ICMP6_FLAG_S; /* Solicited flag. */
|
---|
| 1041 |
|
---|
| 1042 | ICMPBUF->reserved1 = ICMPBUF->reserved2 = ICMPBUF->reserved3 = 0;
|
---|
| 1043 |
|
---|
[262] | 1044 | uip_ipaddr_copy(&ICMPBUF->destipaddr, &ICMPBUF->srcipaddr);
|
---|
| 1045 | uip_ipaddr_copy(&ICMPBUF->srcipaddr, &uip_hostaddr);
|
---|
[101] | 1046 | ICMPBUF->options[0] = ICMP6_OPTION_TARGET_LINK_ADDRESS;
|
---|
| 1047 | ICMPBUF->options[1] = 1; /* Options length, 1 = 8 bytes. */
|
---|
[262] | 1048 | memcpy(&(ICMPBUF->options[2]), &uip_lladdr, sizeof(uip_lladdr));
|
---|
[101] | 1049 | ICMPBUF->icmpchksum = 0;
|
---|
| 1050 | ICMPBUF->icmpchksum = ~uip_icmp6chksum();
|
---|
[262] | 1051 |
|
---|
[101] | 1052 | goto send;
|
---|
| 1053 |
|
---|
| 1054 | }
|
---|
| 1055 | goto drop;
|
---|
| 1056 | } else if(ICMPBUF->type == ICMP6_ECHO) {
|
---|
| 1057 | /* ICMP echo (i.e., ping) processing. This is simple, we only
|
---|
| 1058 | change the ICMP type from ECHO to ECHO_REPLY and update the
|
---|
| 1059 | ICMP checksum before we return the packet. */
|
---|
| 1060 |
|
---|
| 1061 | ICMPBUF->type = ICMP6_ECHO_REPLY;
|
---|
| 1062 |
|
---|
[262] | 1063 | uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
---|
| 1064 | uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
---|
[101] | 1065 | ICMPBUF->icmpchksum = 0;
|
---|
| 1066 | ICMPBUF->icmpchksum = ~uip_icmp6chksum();
|
---|
| 1067 |
|
---|
| 1068 | UIP_STAT(++uip_stat.icmp.sent);
|
---|
| 1069 | goto send;
|
---|
| 1070 | } else {
|
---|
| 1071 | DEBUG_PRINTF("Unknown icmp6 message type %d\n", ICMPBUF->type);
|
---|
| 1072 | UIP_STAT(++uip_stat.icmp.drop);
|
---|
| 1073 | UIP_STAT(++uip_stat.icmp.typeerr);
|
---|
| 1074 | UIP_LOG("icmp: unknown ICMP message.");
|
---|
| 1075 | goto drop;
|
---|
| 1076 | }
|
---|
| 1077 |
|
---|
| 1078 | /* End of IPv6 ICMP processing. */
|
---|
| 1079 |
|
---|
| 1080 | #endif /* !UIP_CONF_IPV6 */
|
---|
| 1081 |
|
---|
| 1082 | #if UIP_UDP
|
---|
| 1083 | /* UDP input processing. */
|
---|
| 1084 | udp_input:
|
---|
| 1085 | /* UDP processing is really just a hack. We don't do anything to the
|
---|
| 1086 | UDP/IP headers, but let the UDP application do all the hard
|
---|
| 1087 | work. If the application sets uip_slen, it has a packet to
|
---|
| 1088 | send. */
|
---|
| 1089 | #if UIP_UDP_CHECKSUMS
|
---|
| 1090 | uip_len = uip_len - UIP_IPUDPH_LEN;
|
---|
| 1091 | uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
---|
| 1092 | if(UDPBUF->udpchksum != 0 && uip_udpchksum() != 0xffff) {
|
---|
| 1093 | UIP_STAT(++uip_stat.udp.drop);
|
---|
| 1094 | UIP_STAT(++uip_stat.udp.chkerr);
|
---|
| 1095 | UIP_LOG("udp: bad checksum.");
|
---|
| 1096 | goto drop;
|
---|
| 1097 | }
|
---|
| 1098 | #else /* UIP_UDP_CHECKSUMS */
|
---|
| 1099 | uip_len = uip_len - UIP_IPUDPH_LEN;
|
---|
| 1100 | #endif /* UIP_UDP_CHECKSUMS */
|
---|
| 1101 |
|
---|
[262] | 1102 | /* Make sure that the UDP destination port number is not zero. */
|
---|
| 1103 | if(UDPBUF->destport == 0) {
|
---|
| 1104 | UIP_LOG("udp: zero port.");
|
---|
| 1105 | goto drop;
|
---|
| 1106 | }
|
---|
| 1107 |
|
---|
[101] | 1108 | /* Demultiplex this UDP packet between the UDP "connections". */
|
---|
| 1109 | for(uip_udp_conn = &uip_udp_conns[0];
|
---|
| 1110 | uip_udp_conn < &uip_udp_conns[UIP_UDP_CONNS];
|
---|
| 1111 | ++uip_udp_conn) {
|
---|
| 1112 | /* If the local UDP port is non-zero, the connection is considered
|
---|
| 1113 | to be used. If so, the local port number is checked against the
|
---|
| 1114 | destination port number in the received packet. If the two port
|
---|
| 1115 | numbers match, the remote port number is checked if the
|
---|
| 1116 | connection is bound to a remote port. Finally, if the
|
---|
| 1117 | connection is bound to a remote IP address, the source IP
|
---|
| 1118 | address of the packet is checked. */
|
---|
| 1119 | if(uip_udp_conn->lport != 0 &&
|
---|
| 1120 | UDPBUF->destport == uip_udp_conn->lport &&
|
---|
| 1121 | (uip_udp_conn->rport == 0 ||
|
---|
| 1122 | UDPBUF->srcport == uip_udp_conn->rport) &&
|
---|
[262] | 1123 | (uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_all_zeroes_addr) ||
|
---|
| 1124 | uip_ipaddr_cmp(&uip_udp_conn->ripaddr, &uip_broadcast_addr) ||
|
---|
| 1125 | uip_ipaddr_cmp(&BUF->srcipaddr, &uip_udp_conn->ripaddr))) {
|
---|
[101] | 1126 | goto udp_found;
|
---|
| 1127 | }
|
---|
| 1128 | }
|
---|
| 1129 | UIP_LOG("udp: no matching connection found");
|
---|
| 1130 | goto drop;
|
---|
| 1131 |
|
---|
| 1132 | udp_found:
|
---|
| 1133 | uip_conn = NULL;
|
---|
| 1134 | uip_flags = UIP_NEWDATA;
|
---|
| 1135 | uip_sappdata = uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPUDPH_LEN];
|
---|
| 1136 | uip_slen = 0;
|
---|
| 1137 | UIP_UDP_APPCALL();
|
---|
[262] | 1138 |
|
---|
[101] | 1139 | udp_send:
|
---|
| 1140 | if(uip_slen == 0) {
|
---|
| 1141 | goto drop;
|
---|
| 1142 | }
|
---|
| 1143 | uip_len = uip_slen + UIP_IPUDPH_LEN;
|
---|
| 1144 |
|
---|
| 1145 | #if UIP_CONF_IPV6
|
---|
| 1146 | /* For IPv6, the IP length field does not include the IPv6 IP header
|
---|
| 1147 | length. */
|
---|
| 1148 | BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
|
---|
| 1149 | BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
|
---|
| 1150 | #else /* UIP_CONF_IPV6 */
|
---|
| 1151 | BUF->len[0] = (uip_len >> 8);
|
---|
| 1152 | BUF->len[1] = (uip_len & 0xff);
|
---|
| 1153 | #endif /* UIP_CONF_IPV6 */
|
---|
| 1154 |
|
---|
| 1155 | BUF->ttl = uip_udp_conn->ttl;
|
---|
| 1156 | BUF->proto = UIP_PROTO_UDP;
|
---|
| 1157 |
|
---|
[262] | 1158 | UDPBUF->udplen = UIP_HTONS(uip_slen + UIP_UDPH_LEN);
|
---|
[101] | 1159 | UDPBUF->udpchksum = 0;
|
---|
| 1160 |
|
---|
| 1161 | BUF->srcport = uip_udp_conn->lport;
|
---|
| 1162 | BUF->destport = uip_udp_conn->rport;
|
---|
| 1163 |
|
---|
[262] | 1164 | uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
---|
| 1165 | uip_ipaddr_copy(&BUF->destipaddr, &uip_udp_conn->ripaddr);
|
---|
[101] | 1166 |
|
---|
| 1167 | uip_appdata = &uip_buf[UIP_LLH_LEN + UIP_IPTCPH_LEN];
|
---|
| 1168 |
|
---|
| 1169 | #if UIP_UDP_CHECKSUMS
|
---|
| 1170 | /* Calculate UDP checksum. */
|
---|
| 1171 | UDPBUF->udpchksum = ~(uip_udpchksum());
|
---|
| 1172 | if(UDPBUF->udpchksum == 0) {
|
---|
| 1173 | UDPBUF->udpchksum = 0xffff;
|
---|
| 1174 | }
|
---|
| 1175 | #endif /* UIP_UDP_CHECKSUMS */
|
---|
| 1176 |
|
---|
| 1177 | goto ip_send_nolen;
|
---|
| 1178 | #endif /* UIP_UDP */
|
---|
| 1179 |
|
---|
| 1180 | /* TCP input processing. */
|
---|
| 1181 | tcp_input:
|
---|
| 1182 | UIP_STAT(++uip_stat.tcp.recv);
|
---|
| 1183 |
|
---|
| 1184 | /* Start of TCP input header processing code. */
|
---|
| 1185 |
|
---|
| 1186 | if(uip_tcpchksum() != 0xffff) { /* Compute and check the TCP
|
---|
| 1187 | checksum. */
|
---|
| 1188 | UIP_STAT(++uip_stat.tcp.drop);
|
---|
| 1189 | UIP_STAT(++uip_stat.tcp.chkerr);
|
---|
| 1190 | UIP_LOG("tcp: bad checksum.");
|
---|
| 1191 | goto drop;
|
---|
| 1192 | }
|
---|
| 1193 |
|
---|
[262] | 1194 | /* Make sure that the TCP port number is not zero. */
|
---|
| 1195 | if(BUF->destport == 0 || BUF->srcport == 0) {
|
---|
| 1196 | UIP_LOG("tcp: zero port.");
|
---|
| 1197 | goto drop;
|
---|
| 1198 | }
|
---|
[101] | 1199 |
|
---|
| 1200 | /* Demultiplex this segment. */
|
---|
| 1201 | /* First check any active connections. */
|
---|
| 1202 | for(uip_connr = &uip_conns[0]; uip_connr <= &uip_conns[UIP_CONNS - 1];
|
---|
| 1203 | ++uip_connr) {
|
---|
| 1204 | if(uip_connr->tcpstateflags != UIP_CLOSED &&
|
---|
| 1205 | BUF->destport == uip_connr->lport &&
|
---|
| 1206 | BUF->srcport == uip_connr->rport &&
|
---|
[262] | 1207 | uip_ipaddr_cmp(&BUF->srcipaddr, &uip_connr->ripaddr)) {
|
---|
[101] | 1208 | goto found;
|
---|
| 1209 | }
|
---|
| 1210 | }
|
---|
| 1211 |
|
---|
| 1212 | /* If we didn't find and active connection that expected the packet,
|
---|
| 1213 | either this packet is an old duplicate, or this is a SYN packet
|
---|
| 1214 | destined for a connection in LISTEN. If the SYN flag isn't set,
|
---|
| 1215 | it is an old packet and we send a RST. */
|
---|
| 1216 | if((BUF->flags & TCP_CTL) != TCP_SYN) {
|
---|
| 1217 | goto reset;
|
---|
| 1218 | }
|
---|
| 1219 |
|
---|
| 1220 | tmp16 = BUF->destport;
|
---|
| 1221 | /* Next, check listening connections. */
|
---|
| 1222 | for(c = 0; c < UIP_LISTENPORTS; ++c) {
|
---|
[262] | 1223 | if(tmp16 == uip_listenports[c]) {
|
---|
[101] | 1224 | goto found_listen;
|
---|
[262] | 1225 | }
|
---|
[101] | 1226 | }
|
---|
| 1227 |
|
---|
| 1228 | /* No matching connection found, so we send a RST packet. */
|
---|
| 1229 | UIP_STAT(++uip_stat.tcp.synrst);
|
---|
[262] | 1230 |
|
---|
[101] | 1231 | reset:
|
---|
| 1232 | /* We do not send resets in response to resets. */
|
---|
| 1233 | if(BUF->flags & TCP_RST) {
|
---|
| 1234 | goto drop;
|
---|
| 1235 | }
|
---|
| 1236 |
|
---|
| 1237 | UIP_STAT(++uip_stat.tcp.rst);
|
---|
| 1238 |
|
---|
| 1239 | BUF->flags = TCP_RST | TCP_ACK;
|
---|
| 1240 | uip_len = UIP_IPTCPH_LEN;
|
---|
| 1241 | BUF->tcpoffset = 5 << 4;
|
---|
| 1242 |
|
---|
| 1243 | /* Flip the seqno and ackno fields in the TCP header. */
|
---|
| 1244 | c = BUF->seqno[3];
|
---|
| 1245 | BUF->seqno[3] = BUF->ackno[3];
|
---|
| 1246 | BUF->ackno[3] = c;
|
---|
| 1247 |
|
---|
| 1248 | c = BUF->seqno[2];
|
---|
| 1249 | BUF->seqno[2] = BUF->ackno[2];
|
---|
| 1250 | BUF->ackno[2] = c;
|
---|
| 1251 |
|
---|
| 1252 | c = BUF->seqno[1];
|
---|
| 1253 | BUF->seqno[1] = BUF->ackno[1];
|
---|
| 1254 | BUF->ackno[1] = c;
|
---|
| 1255 |
|
---|
| 1256 | c = BUF->seqno[0];
|
---|
| 1257 | BUF->seqno[0] = BUF->ackno[0];
|
---|
| 1258 | BUF->ackno[0] = c;
|
---|
| 1259 |
|
---|
| 1260 | /* We also have to increase the sequence number we are
|
---|
| 1261 | acknowledging. If the least significant byte overflowed, we need
|
---|
| 1262 | to propagate the carry to the other bytes as well. */
|
---|
| 1263 | if(++BUF->ackno[3] == 0) {
|
---|
| 1264 | if(++BUF->ackno[2] == 0) {
|
---|
| 1265 | if(++BUF->ackno[1] == 0) {
|
---|
| 1266 | ++BUF->ackno[0];
|
---|
| 1267 | }
|
---|
| 1268 | }
|
---|
| 1269 | }
|
---|
| 1270 |
|
---|
| 1271 | /* Swap port numbers. */
|
---|
| 1272 | tmp16 = BUF->srcport;
|
---|
| 1273 | BUF->srcport = BUF->destport;
|
---|
| 1274 | BUF->destport = tmp16;
|
---|
| 1275 |
|
---|
| 1276 | /* Swap IP addresses. */
|
---|
[262] | 1277 | uip_ipaddr_copy(&BUF->destipaddr, &BUF->srcipaddr);
|
---|
| 1278 | uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
---|
[101] | 1279 |
|
---|
| 1280 | /* And send out the RST packet! */
|
---|
| 1281 | goto tcp_send_noconn;
|
---|
| 1282 |
|
---|
| 1283 | /* This label will be jumped to if we matched the incoming packet
|
---|
| 1284 | with a connection in LISTEN. In that case, we should create a new
|
---|
| 1285 | connection and send a SYNACK in return. */
|
---|
| 1286 | found_listen:
|
---|
[262] | 1287 | /* First we check if there are any connections available. Unused
|
---|
[101] | 1288 | connections are kept in the same table as used connections, but
|
---|
| 1289 | unused ones have the tcpstate set to CLOSED. Also, connections in
|
---|
| 1290 | TIME_WAIT are kept track of and we'll use the oldest one if no
|
---|
| 1291 | CLOSED connections are found. Thanks to Eddie C. Dost for a very
|
---|
| 1292 | nice algorithm for the TIME_WAIT search. */
|
---|
| 1293 | uip_connr = 0;
|
---|
| 1294 | for(c = 0; c < UIP_CONNS; ++c) {
|
---|
| 1295 | if(uip_conns[c].tcpstateflags == UIP_CLOSED) {
|
---|
| 1296 | uip_connr = &uip_conns[c];
|
---|
| 1297 | break;
|
---|
| 1298 | }
|
---|
| 1299 | if(uip_conns[c].tcpstateflags == UIP_TIME_WAIT) {
|
---|
| 1300 | if(uip_connr == 0 ||
|
---|
| 1301 | uip_conns[c].timer > uip_connr->timer) {
|
---|
| 1302 | uip_connr = &uip_conns[c];
|
---|
| 1303 | }
|
---|
| 1304 | }
|
---|
| 1305 | }
|
---|
| 1306 |
|
---|
| 1307 | if(uip_connr == 0) {
|
---|
| 1308 | /* All connections are used already, we drop packet and hope that
|
---|
| 1309 | the remote end will retransmit the packet at a time when we
|
---|
| 1310 | have more spare connections. */
|
---|
| 1311 | UIP_STAT(++uip_stat.tcp.syndrop);
|
---|
| 1312 | UIP_LOG("tcp: found no unused connections.");
|
---|
| 1313 | goto drop;
|
---|
| 1314 | }
|
---|
| 1315 | uip_conn = uip_connr;
|
---|
| 1316 |
|
---|
| 1317 | /* Fill in the necessary fields for the new connection. */
|
---|
| 1318 | uip_connr->rto = uip_connr->timer = UIP_RTO;
|
---|
| 1319 | uip_connr->sa = 0;
|
---|
| 1320 | uip_connr->sv = 4;
|
---|
| 1321 | uip_connr->nrtx = 0;
|
---|
| 1322 | uip_connr->lport = BUF->destport;
|
---|
| 1323 | uip_connr->rport = BUF->srcport;
|
---|
[262] | 1324 | uip_ipaddr_copy(&uip_connr->ripaddr, &BUF->srcipaddr);
|
---|
[101] | 1325 | uip_connr->tcpstateflags = UIP_SYN_RCVD;
|
---|
| 1326 |
|
---|
| 1327 | uip_connr->snd_nxt[0] = iss[0];
|
---|
| 1328 | uip_connr->snd_nxt[1] = iss[1];
|
---|
| 1329 | uip_connr->snd_nxt[2] = iss[2];
|
---|
| 1330 | uip_connr->snd_nxt[3] = iss[3];
|
---|
| 1331 | uip_connr->len = 1;
|
---|
| 1332 |
|
---|
| 1333 | /* rcv_nxt should be the seqno from the incoming packet + 1. */
|
---|
| 1334 | uip_connr->rcv_nxt[3] = BUF->seqno[3];
|
---|
| 1335 | uip_connr->rcv_nxt[2] = BUF->seqno[2];
|
---|
| 1336 | uip_connr->rcv_nxt[1] = BUF->seqno[1];
|
---|
| 1337 | uip_connr->rcv_nxt[0] = BUF->seqno[0];
|
---|
| 1338 | uip_add_rcv_nxt(1);
|
---|
| 1339 |
|
---|
| 1340 | /* Parse the TCP MSS option, if present. */
|
---|
| 1341 | if((BUF->tcpoffset & 0xf0) > 0x50) {
|
---|
| 1342 | for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
|
---|
| 1343 | opt = uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + c];
|
---|
| 1344 | if(opt == TCP_OPT_END) {
|
---|
| 1345 | /* End of options. */
|
---|
| 1346 | break;
|
---|
| 1347 | } else if(opt == TCP_OPT_NOOP) {
|
---|
| 1348 | ++c;
|
---|
| 1349 | /* NOP option. */
|
---|
| 1350 | } else if(opt == TCP_OPT_MSS &&
|
---|
| 1351 | uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
|
---|
| 1352 | /* An MSS option with the right option length. */
|
---|
[158] | 1353 | tmp16 = ((uint16_t)uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
|
---|
| 1354 | (uint16_t)uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + c];
|
---|
[101] | 1355 | uip_connr->initialmss = uip_connr->mss =
|
---|
| 1356 | tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
|
---|
| 1357 |
|
---|
| 1358 | /* And we are done processing options. */
|
---|
| 1359 | break;
|
---|
| 1360 | } else {
|
---|
| 1361 | /* All other options have a length field, so that we easily
|
---|
| 1362 | can skip past them. */
|
---|
| 1363 | if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
|
---|
| 1364 | /* If the length field is zero, the options are malformed
|
---|
| 1365 | and we don't process them further. */
|
---|
| 1366 | break;
|
---|
| 1367 | }
|
---|
| 1368 | c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
|
---|
| 1369 | }
|
---|
| 1370 | }
|
---|
| 1371 | }
|
---|
| 1372 |
|
---|
| 1373 | /* Our response will be a SYNACK. */
|
---|
| 1374 | #if UIP_ACTIVE_OPEN
|
---|
| 1375 | tcp_send_synack:
|
---|
| 1376 | BUF->flags = TCP_ACK;
|
---|
| 1377 |
|
---|
| 1378 | tcp_send_syn:
|
---|
| 1379 | BUF->flags |= TCP_SYN;
|
---|
| 1380 | #else /* UIP_ACTIVE_OPEN */
|
---|
| 1381 | tcp_send_synack:
|
---|
| 1382 | BUF->flags = TCP_SYN | TCP_ACK;
|
---|
| 1383 | #endif /* UIP_ACTIVE_OPEN */
|
---|
| 1384 |
|
---|
| 1385 | /* We send out the TCP Maximum Segment Size option with our
|
---|
| 1386 | SYNACK. */
|
---|
| 1387 | BUF->optdata[0] = TCP_OPT_MSS;
|
---|
| 1388 | BUF->optdata[1] = TCP_OPT_MSS_LEN;
|
---|
| 1389 | BUF->optdata[2] = (UIP_TCP_MSS) / 256;
|
---|
| 1390 | BUF->optdata[3] = (UIP_TCP_MSS) & 255;
|
---|
| 1391 | uip_len = UIP_IPTCPH_LEN + TCP_OPT_MSS_LEN;
|
---|
| 1392 | BUF->tcpoffset = ((UIP_TCPH_LEN + TCP_OPT_MSS_LEN) / 4) << 4;
|
---|
| 1393 | goto tcp_send;
|
---|
| 1394 |
|
---|
| 1395 | /* This label will be jumped to if we found an active connection. */
|
---|
| 1396 | found:
|
---|
| 1397 | uip_conn = uip_connr;
|
---|
| 1398 | uip_flags = 0;
|
---|
| 1399 | /* We do a very naive form of TCP reset processing; we just accept
|
---|
| 1400 | any RST and kill our connection. We should in fact check if the
|
---|
| 1401 | sequence number of this reset is wihtin our advertised window
|
---|
| 1402 | before we accept the reset. */
|
---|
| 1403 | if(BUF->flags & TCP_RST) {
|
---|
| 1404 | uip_connr->tcpstateflags = UIP_CLOSED;
|
---|
| 1405 | UIP_LOG("tcp: got reset, aborting connection.");
|
---|
| 1406 | uip_flags = UIP_ABORT;
|
---|
| 1407 | UIP_APPCALL();
|
---|
| 1408 | goto drop;
|
---|
| 1409 | }
|
---|
[262] | 1410 | /* Calculate the length of the data, if the application has sent
|
---|
[101] | 1411 | any data to us. */
|
---|
| 1412 | c = (BUF->tcpoffset >> 4) << 2;
|
---|
| 1413 | /* uip_len will contain the length of the actual TCP data. This is
|
---|
| 1414 | calculated by subtracing the length of the TCP header (in
|
---|
| 1415 | c) and the length of the IP header (20 bytes). */
|
---|
| 1416 | uip_len = uip_len - c - UIP_IPH_LEN;
|
---|
| 1417 |
|
---|
| 1418 | /* First, check if the sequence number of the incoming packet is
|
---|
| 1419 | what we're expecting next. If not, we send out an ACK with the
|
---|
[262] | 1420 | correct numbers in, unless we are in the SYN_RCVD state and
|
---|
| 1421 | receive a SYN, in which case we should retransmit our SYNACK
|
---|
| 1422 | (which is done futher down). */
|
---|
| 1423 | if(!((((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_SENT) &&
|
---|
| 1424 | ((BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK))) ||
|
---|
| 1425 | (((uip_connr->tcpstateflags & UIP_TS_MASK) == UIP_SYN_RCVD) &&
|
---|
| 1426 | ((BUF->flags & TCP_CTL) == TCP_SYN)))) {
|
---|
[101] | 1427 | if((uip_len > 0 || ((BUF->flags & (TCP_SYN | TCP_FIN)) != 0)) &&
|
---|
| 1428 | (BUF->seqno[0] != uip_connr->rcv_nxt[0] ||
|
---|
| 1429 | BUF->seqno[1] != uip_connr->rcv_nxt[1] ||
|
---|
| 1430 | BUF->seqno[2] != uip_connr->rcv_nxt[2] ||
|
---|
| 1431 | BUF->seqno[3] != uip_connr->rcv_nxt[3])) {
|
---|
| 1432 | goto tcp_send_ack;
|
---|
| 1433 | }
|
---|
| 1434 | }
|
---|
| 1435 |
|
---|
| 1436 | /* Next, check if the incoming segment acknowledges any outstanding
|
---|
| 1437 | data. If so, we update the sequence number, reset the length of
|
---|
| 1438 | the outstanding data, calculate RTT estimations, and reset the
|
---|
| 1439 | retransmission timer. */
|
---|
| 1440 | if((BUF->flags & TCP_ACK) && uip_outstanding(uip_connr)) {
|
---|
| 1441 | uip_add32(uip_connr->snd_nxt, uip_connr->len);
|
---|
| 1442 |
|
---|
| 1443 | if(BUF->ackno[0] == uip_acc32[0] &&
|
---|
| 1444 | BUF->ackno[1] == uip_acc32[1] &&
|
---|
| 1445 | BUF->ackno[2] == uip_acc32[2] &&
|
---|
| 1446 | BUF->ackno[3] == uip_acc32[3]) {
|
---|
| 1447 | /* Update sequence number. */
|
---|
| 1448 | uip_connr->snd_nxt[0] = uip_acc32[0];
|
---|
| 1449 | uip_connr->snd_nxt[1] = uip_acc32[1];
|
---|
| 1450 | uip_connr->snd_nxt[2] = uip_acc32[2];
|
---|
| 1451 | uip_connr->snd_nxt[3] = uip_acc32[3];
|
---|
| 1452 |
|
---|
| 1453 | /* Do RTT estimation, unless we have done retransmissions. */
|
---|
| 1454 | if(uip_connr->nrtx == 0) {
|
---|
| 1455 | signed char m;
|
---|
| 1456 | m = uip_connr->rto - uip_connr->timer;
|
---|
| 1457 | /* This is taken directly from VJs original code in his paper */
|
---|
| 1458 | m = m - (uip_connr->sa >> 3);
|
---|
| 1459 | uip_connr->sa += m;
|
---|
| 1460 | if(m < 0) {
|
---|
| 1461 | m = -m;
|
---|
| 1462 | }
|
---|
| 1463 | m = m - (uip_connr->sv >> 2);
|
---|
| 1464 | uip_connr->sv += m;
|
---|
| 1465 | uip_connr->rto = (uip_connr->sa >> 3) + uip_connr->sv;
|
---|
| 1466 |
|
---|
| 1467 | }
|
---|
| 1468 | /* Set the acknowledged flag. */
|
---|
| 1469 | uip_flags = UIP_ACKDATA;
|
---|
| 1470 | /* Reset the retransmission timer. */
|
---|
| 1471 | uip_connr->timer = uip_connr->rto;
|
---|
| 1472 |
|
---|
| 1473 | /* Reset length of outstanding data. */
|
---|
| 1474 | uip_connr->len = 0;
|
---|
| 1475 | }
|
---|
| 1476 |
|
---|
| 1477 | }
|
---|
| 1478 |
|
---|
| 1479 | /* Do different things depending on in what state the connection is. */
|
---|
| 1480 | switch(uip_connr->tcpstateflags & UIP_TS_MASK) {
|
---|
| 1481 | /* CLOSED and LISTEN are not handled here. CLOSE_WAIT is not
|
---|
| 1482 | implemented, since we force the application to close when the
|
---|
| 1483 | peer sends a FIN (hence the application goes directly from
|
---|
| 1484 | ESTABLISHED to LAST_ACK). */
|
---|
| 1485 | case UIP_SYN_RCVD:
|
---|
| 1486 | /* In SYN_RCVD we have sent out a SYNACK in response to a SYN, and
|
---|
| 1487 | we are waiting for an ACK that acknowledges the data we sent
|
---|
| 1488 | out the last time. Therefore, we want to have the UIP_ACKDATA
|
---|
| 1489 | flag set. If so, we enter the ESTABLISHED state. */
|
---|
| 1490 | if(uip_flags & UIP_ACKDATA) {
|
---|
| 1491 | uip_connr->tcpstateflags = UIP_ESTABLISHED;
|
---|
| 1492 | uip_flags = UIP_CONNECTED;
|
---|
| 1493 | uip_connr->len = 0;
|
---|
| 1494 | if(uip_len > 0) {
|
---|
| 1495 | uip_flags |= UIP_NEWDATA;
|
---|
| 1496 | uip_add_rcv_nxt(uip_len);
|
---|
| 1497 | }
|
---|
| 1498 | uip_slen = 0;
|
---|
| 1499 | UIP_APPCALL();
|
---|
| 1500 | goto appsend;
|
---|
| 1501 | }
|
---|
[262] | 1502 | /* We need to retransmit the SYNACK */
|
---|
| 1503 | if((BUF->flags & TCP_CTL) == TCP_SYN) {
|
---|
| 1504 | goto tcp_send_synack;
|
---|
| 1505 | }
|
---|
[101] | 1506 | goto drop;
|
---|
| 1507 | #if UIP_ACTIVE_OPEN
|
---|
| 1508 | case UIP_SYN_SENT:
|
---|
| 1509 | /* In SYN_SENT, we wait for a SYNACK that is sent in response to
|
---|
| 1510 | our SYN. The rcv_nxt is set to sequence number in the SYNACK
|
---|
| 1511 | plus one, and we send an ACK. We move into the ESTABLISHED
|
---|
| 1512 | state. */
|
---|
| 1513 | if((uip_flags & UIP_ACKDATA) &&
|
---|
| 1514 | (BUF->flags & TCP_CTL) == (TCP_SYN | TCP_ACK)) {
|
---|
| 1515 |
|
---|
| 1516 | /* Parse the TCP MSS option, if present. */
|
---|
| 1517 | if((BUF->tcpoffset & 0xf0) > 0x50) {
|
---|
| 1518 | for(c = 0; c < ((BUF->tcpoffset >> 4) - 5) << 2 ;) {
|
---|
| 1519 | opt = uip_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + c];
|
---|
| 1520 | if(opt == TCP_OPT_END) {
|
---|
| 1521 | /* End of options. */
|
---|
| 1522 | break;
|
---|
| 1523 | } else if(opt == TCP_OPT_NOOP) {
|
---|
| 1524 | ++c;
|
---|
| 1525 | /* NOP option. */
|
---|
| 1526 | } else if(opt == TCP_OPT_MSS &&
|
---|
| 1527 | uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == TCP_OPT_MSS_LEN) {
|
---|
| 1528 | /* An MSS option with the right option length. */
|
---|
| 1529 | tmp16 = (uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + c] << 8) |
|
---|
| 1530 | uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + c];
|
---|
| 1531 | uip_connr->initialmss =
|
---|
| 1532 | uip_connr->mss = tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
|
---|
| 1533 |
|
---|
| 1534 | /* And we are done processing options. */
|
---|
| 1535 | break;
|
---|
| 1536 | } else {
|
---|
| 1537 | /* All other options have a length field, so that we easily
|
---|
| 1538 | can skip past them. */
|
---|
| 1539 | if(uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c] == 0) {
|
---|
| 1540 | /* If the length field is zero, the options are malformed
|
---|
| 1541 | and we don't process them further. */
|
---|
| 1542 | break;
|
---|
| 1543 | }
|
---|
| 1544 | c += uip_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 1 + c];
|
---|
| 1545 | }
|
---|
| 1546 | }
|
---|
| 1547 | }
|
---|
| 1548 | uip_connr->tcpstateflags = UIP_ESTABLISHED;
|
---|
| 1549 | uip_connr->rcv_nxt[0] = BUF->seqno[0];
|
---|
| 1550 | uip_connr->rcv_nxt[1] = BUF->seqno[1];
|
---|
| 1551 | uip_connr->rcv_nxt[2] = BUF->seqno[2];
|
---|
| 1552 | uip_connr->rcv_nxt[3] = BUF->seqno[3];
|
---|
| 1553 | uip_add_rcv_nxt(1);
|
---|
| 1554 | uip_flags = UIP_CONNECTED | UIP_NEWDATA;
|
---|
| 1555 | uip_connr->len = 0;
|
---|
| 1556 | uip_len = 0;
|
---|
| 1557 | uip_slen = 0;
|
---|
| 1558 | UIP_APPCALL();
|
---|
| 1559 | goto appsend;
|
---|
| 1560 | }
|
---|
| 1561 | /* Inform the application that the connection failed */
|
---|
| 1562 | uip_flags = UIP_ABORT;
|
---|
| 1563 | UIP_APPCALL();
|
---|
| 1564 | /* The connection is closed after we send the RST */
|
---|
| 1565 | uip_conn->tcpstateflags = UIP_CLOSED;
|
---|
| 1566 | goto reset;
|
---|
| 1567 | #endif /* UIP_ACTIVE_OPEN */
|
---|
| 1568 |
|
---|
| 1569 | case UIP_ESTABLISHED:
|
---|
| 1570 | /* In the ESTABLISHED state, we call upon the application to feed
|
---|
| 1571 | data into the uip_buf. If the UIP_ACKDATA flag is set, the
|
---|
| 1572 | application should put new data into the buffer, otherwise we are
|
---|
| 1573 | retransmitting an old segment, and the application should put that
|
---|
| 1574 | data into the buffer.
|
---|
| 1575 |
|
---|
| 1576 | If the incoming packet is a FIN, we should close the connection on
|
---|
| 1577 | this side as well, and we send out a FIN and enter the LAST_ACK
|
---|
| 1578 | state. We require that there is no outstanding data; otherwise the
|
---|
| 1579 | sequence numbers will be screwed up. */
|
---|
| 1580 |
|
---|
| 1581 | if(BUF->flags & TCP_FIN && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
|
---|
| 1582 | if(uip_outstanding(uip_connr)) {
|
---|
| 1583 | goto drop;
|
---|
| 1584 | }
|
---|
| 1585 | uip_add_rcv_nxt(1 + uip_len);
|
---|
| 1586 | uip_flags |= UIP_CLOSE;
|
---|
| 1587 | if(uip_len > 0) {
|
---|
| 1588 | uip_flags |= UIP_NEWDATA;
|
---|
| 1589 | }
|
---|
| 1590 | UIP_APPCALL();
|
---|
| 1591 | uip_connr->len = 1;
|
---|
| 1592 | uip_connr->tcpstateflags = UIP_LAST_ACK;
|
---|
| 1593 | uip_connr->nrtx = 0;
|
---|
| 1594 | tcp_send_finack:
|
---|
| 1595 | BUF->flags = TCP_FIN | TCP_ACK;
|
---|
| 1596 | goto tcp_send_nodata;
|
---|
| 1597 | }
|
---|
| 1598 |
|
---|
| 1599 | /* Check the URG flag. If this is set, the segment carries urgent
|
---|
| 1600 | data that we must pass to the application. */
|
---|
| 1601 | if((BUF->flags & TCP_URG) != 0) {
|
---|
| 1602 | #if UIP_URGDATA > 0
|
---|
| 1603 | uip_urglen = (BUF->urgp[0] << 8) | BUF->urgp[1];
|
---|
| 1604 | if(uip_urglen > uip_len) {
|
---|
| 1605 | /* There is more urgent data in the next segment to come. */
|
---|
| 1606 | uip_urglen = uip_len;
|
---|
| 1607 | }
|
---|
| 1608 | uip_add_rcv_nxt(uip_urglen);
|
---|
| 1609 | uip_len -= uip_urglen;
|
---|
| 1610 | uip_urgdata = uip_appdata;
|
---|
| 1611 | uip_appdata += uip_urglen;
|
---|
| 1612 | } else {
|
---|
| 1613 | uip_urglen = 0;
|
---|
| 1614 | #else /* UIP_URGDATA > 0 */
|
---|
| 1615 | uip_appdata = ((char *)uip_appdata) + ((BUF->urgp[0] << 8) | BUF->urgp[1]);
|
---|
| 1616 | uip_len -= (BUF->urgp[0] << 8) | BUF->urgp[1];
|
---|
| 1617 | #endif /* UIP_URGDATA > 0 */
|
---|
| 1618 | }
|
---|
| 1619 |
|
---|
| 1620 | /* If uip_len > 0 we have TCP data in the packet, and we flag this
|
---|
| 1621 | by setting the UIP_NEWDATA flag and update the sequence number
|
---|
| 1622 | we acknowledge. If the application has stopped the dataflow
|
---|
| 1623 | using uip_stop(), we must not accept any data packets from the
|
---|
| 1624 | remote host. */
|
---|
| 1625 | if(uip_len > 0 && !(uip_connr->tcpstateflags & UIP_STOPPED)) {
|
---|
| 1626 | uip_flags |= UIP_NEWDATA;
|
---|
| 1627 | uip_add_rcv_nxt(uip_len);
|
---|
| 1628 | }
|
---|
| 1629 |
|
---|
| 1630 | /* Check if the available buffer space advertised by the other end
|
---|
| 1631 | is smaller than the initial MSS for this connection. If so, we
|
---|
| 1632 | set the current MSS to the window size to ensure that the
|
---|
| 1633 | application does not send more data than the other end can
|
---|
| 1634 | handle.
|
---|
| 1635 |
|
---|
| 1636 | If the remote host advertises a zero window, we set the MSS to
|
---|
| 1637 | the initial MSS so that the application will send an entire MSS
|
---|
| 1638 | of data. This data will not be acknowledged by the receiver,
|
---|
| 1639 | and the application will retransmit it. This is called the
|
---|
| 1640 | "persistent timer" and uses the retransmission mechanim.
|
---|
| 1641 | */
|
---|
[158] | 1642 | tmp16 = ((uint16_t)BUF->wnd[0] << 8) + (uint16_t)BUF->wnd[1];
|
---|
[101] | 1643 | if(tmp16 > uip_connr->initialmss ||
|
---|
| 1644 | tmp16 == 0) {
|
---|
| 1645 | tmp16 = uip_connr->initialmss;
|
---|
| 1646 | }
|
---|
| 1647 | uip_connr->mss = tmp16;
|
---|
| 1648 |
|
---|
| 1649 | /* If this packet constitutes an ACK for outstanding data (flagged
|
---|
| 1650 | by the UIP_ACKDATA flag, we should call the application since it
|
---|
| 1651 | might want to send more data. If the incoming packet had data
|
---|
| 1652 | from the peer (as flagged by the UIP_NEWDATA flag), the
|
---|
| 1653 | application must also be notified.
|
---|
| 1654 |
|
---|
| 1655 | When the application is called, the global variable uip_len
|
---|
| 1656 | contains the length of the incoming data. The application can
|
---|
| 1657 | access the incoming data through the global pointer
|
---|
| 1658 | uip_appdata, which usually points UIP_IPTCPH_LEN + UIP_LLH_LEN
|
---|
| 1659 | bytes into the uip_buf array.
|
---|
| 1660 |
|
---|
| 1661 | If the application wishes to send any data, this data should be
|
---|
| 1662 | put into the uip_appdata and the length of the data should be
|
---|
| 1663 | put into uip_len. If the application don't have any data to
|
---|
| 1664 | send, uip_len must be set to 0. */
|
---|
| 1665 | if(uip_flags & (UIP_NEWDATA | UIP_ACKDATA)) {
|
---|
| 1666 | uip_slen = 0;
|
---|
| 1667 | UIP_APPCALL();
|
---|
| 1668 |
|
---|
| 1669 | appsend:
|
---|
| 1670 |
|
---|
| 1671 | if(uip_flags & UIP_ABORT) {
|
---|
| 1672 | uip_slen = 0;
|
---|
| 1673 | uip_connr->tcpstateflags = UIP_CLOSED;
|
---|
| 1674 | BUF->flags = TCP_RST | TCP_ACK;
|
---|
| 1675 | goto tcp_send_nodata;
|
---|
| 1676 | }
|
---|
| 1677 |
|
---|
| 1678 | if(uip_flags & UIP_CLOSE) {
|
---|
| 1679 | uip_slen = 0;
|
---|
| 1680 | uip_connr->len = 1;
|
---|
| 1681 | uip_connr->tcpstateflags = UIP_FIN_WAIT_1;
|
---|
| 1682 | uip_connr->nrtx = 0;
|
---|
| 1683 | BUF->flags = TCP_FIN | TCP_ACK;
|
---|
| 1684 | goto tcp_send_nodata;
|
---|
| 1685 | }
|
---|
| 1686 |
|
---|
| 1687 | /* If uip_slen > 0, the application has data to be sent. */
|
---|
| 1688 | if(uip_slen > 0) {
|
---|
| 1689 |
|
---|
| 1690 | /* If the connection has acknowledged data, the contents of
|
---|
| 1691 | the ->len variable should be discarded. */
|
---|
| 1692 | if((uip_flags & UIP_ACKDATA) != 0) {
|
---|
| 1693 | uip_connr->len = 0;
|
---|
| 1694 | }
|
---|
| 1695 |
|
---|
| 1696 | /* If the ->len variable is non-zero the connection has
|
---|
| 1697 | already data in transit and cannot send anymore right
|
---|
| 1698 | now. */
|
---|
| 1699 | if(uip_connr->len == 0) {
|
---|
| 1700 |
|
---|
| 1701 | /* The application cannot send more than what is allowed by
|
---|
| 1702 | the mss (the minumum of the MSS and the available
|
---|
| 1703 | window). */
|
---|
| 1704 | if(uip_slen > uip_connr->mss) {
|
---|
| 1705 | uip_slen = uip_connr->mss;
|
---|
| 1706 | }
|
---|
| 1707 |
|
---|
| 1708 | /* Remember how much data we send out now so that we know
|
---|
| 1709 | when everything has been acknowledged. */
|
---|
| 1710 | uip_connr->len = uip_slen;
|
---|
| 1711 | } else {
|
---|
| 1712 |
|
---|
| 1713 | /* If the application already had unacknowledged data, we
|
---|
| 1714 | make sure that the application does not send (i.e.,
|
---|
| 1715 | retransmit) out more than it previously sent out. */
|
---|
| 1716 | uip_slen = uip_connr->len;
|
---|
| 1717 | }
|
---|
| 1718 | }
|
---|
| 1719 | uip_connr->nrtx = 0;
|
---|
| 1720 | apprexmit:
|
---|
| 1721 | uip_appdata = uip_sappdata;
|
---|
| 1722 |
|
---|
| 1723 | /* If the application has data to be sent, or if the incoming
|
---|
| 1724 | packet had new data in it, we must send out a packet. */
|
---|
| 1725 | if(uip_slen > 0 && uip_connr->len > 0) {
|
---|
| 1726 | /* Add the length of the IP and TCP headers. */
|
---|
| 1727 | uip_len = uip_connr->len + UIP_TCPIP_HLEN;
|
---|
| 1728 | /* We always set the ACK flag in response packets. */
|
---|
| 1729 | BUF->flags = TCP_ACK | TCP_PSH;
|
---|
| 1730 | /* Send the packet. */
|
---|
| 1731 | goto tcp_send_noopts;
|
---|
| 1732 | }
|
---|
| 1733 | /* If there is no data to send, just send out a pure ACK if
|
---|
| 1734 | there is newdata. */
|
---|
| 1735 | if(uip_flags & UIP_NEWDATA) {
|
---|
| 1736 | uip_len = UIP_TCPIP_HLEN;
|
---|
| 1737 | BUF->flags = TCP_ACK;
|
---|
| 1738 | goto tcp_send_noopts;
|
---|
| 1739 | }
|
---|
| 1740 | }
|
---|
| 1741 | goto drop;
|
---|
| 1742 | case UIP_LAST_ACK:
|
---|
| 1743 | /* We can close this connection if the peer has acknowledged our
|
---|
| 1744 | FIN. This is indicated by the UIP_ACKDATA flag. */
|
---|
| 1745 | if(uip_flags & UIP_ACKDATA) {
|
---|
| 1746 | uip_connr->tcpstateflags = UIP_CLOSED;
|
---|
| 1747 | uip_flags = UIP_CLOSE;
|
---|
| 1748 | UIP_APPCALL();
|
---|
| 1749 | }
|
---|
| 1750 | break;
|
---|
| 1751 |
|
---|
| 1752 | case UIP_FIN_WAIT_1:
|
---|
| 1753 | /* The application has closed the connection, but the remote host
|
---|
| 1754 | hasn't closed its end yet. Thus we do nothing but wait for a
|
---|
| 1755 | FIN from the other side. */
|
---|
| 1756 | if(uip_len > 0) {
|
---|
| 1757 | uip_add_rcv_nxt(uip_len);
|
---|
| 1758 | }
|
---|
| 1759 | if(BUF->flags & TCP_FIN) {
|
---|
| 1760 | if(uip_flags & UIP_ACKDATA) {
|
---|
| 1761 | uip_connr->tcpstateflags = UIP_TIME_WAIT;
|
---|
| 1762 | uip_connr->timer = 0;
|
---|
| 1763 | uip_connr->len = 0;
|
---|
| 1764 | } else {
|
---|
| 1765 | uip_connr->tcpstateflags = UIP_CLOSING;
|
---|
| 1766 | }
|
---|
| 1767 | uip_add_rcv_nxt(1);
|
---|
| 1768 | uip_flags = UIP_CLOSE;
|
---|
| 1769 | UIP_APPCALL();
|
---|
| 1770 | goto tcp_send_ack;
|
---|
| 1771 | } else if(uip_flags & UIP_ACKDATA) {
|
---|
| 1772 | uip_connr->tcpstateflags = UIP_FIN_WAIT_2;
|
---|
| 1773 | uip_connr->len = 0;
|
---|
| 1774 | goto drop;
|
---|
| 1775 | }
|
---|
| 1776 | if(uip_len > 0) {
|
---|
| 1777 | goto tcp_send_ack;
|
---|
| 1778 | }
|
---|
| 1779 | goto drop;
|
---|
| 1780 |
|
---|
| 1781 | case UIP_FIN_WAIT_2:
|
---|
| 1782 | if(uip_len > 0) {
|
---|
| 1783 | uip_add_rcv_nxt(uip_len);
|
---|
| 1784 | }
|
---|
| 1785 | if(BUF->flags & TCP_FIN) {
|
---|
| 1786 | uip_connr->tcpstateflags = UIP_TIME_WAIT;
|
---|
| 1787 | uip_connr->timer = 0;
|
---|
| 1788 | uip_add_rcv_nxt(1);
|
---|
| 1789 | uip_flags = UIP_CLOSE;
|
---|
| 1790 | UIP_APPCALL();
|
---|
| 1791 | goto tcp_send_ack;
|
---|
| 1792 | }
|
---|
| 1793 | if(uip_len > 0) {
|
---|
| 1794 | goto tcp_send_ack;
|
---|
| 1795 | }
|
---|
| 1796 | goto drop;
|
---|
| 1797 |
|
---|
| 1798 | case UIP_TIME_WAIT:
|
---|
| 1799 | goto tcp_send_ack;
|
---|
| 1800 |
|
---|
| 1801 | case UIP_CLOSING:
|
---|
| 1802 | if(uip_flags & UIP_ACKDATA) {
|
---|
| 1803 | uip_connr->tcpstateflags = UIP_TIME_WAIT;
|
---|
| 1804 | uip_connr->timer = 0;
|
---|
| 1805 | }
|
---|
| 1806 | }
|
---|
| 1807 | goto drop;
|
---|
| 1808 |
|
---|
| 1809 | /* We jump here when we are ready to send the packet, and just want
|
---|
| 1810 | to set the appropriate TCP sequence numbers in the TCP header. */
|
---|
| 1811 | tcp_send_ack:
|
---|
| 1812 | BUF->flags = TCP_ACK;
|
---|
[262] | 1813 |
|
---|
[101] | 1814 | tcp_send_nodata:
|
---|
| 1815 | uip_len = UIP_IPTCPH_LEN;
|
---|
[262] | 1816 |
|
---|
[101] | 1817 | tcp_send_noopts:
|
---|
| 1818 | BUF->tcpoffset = (UIP_TCPH_LEN / 4) << 4;
|
---|
[262] | 1819 |
|
---|
[101] | 1820 | /* We're done with the input processing. We are now ready to send a
|
---|
| 1821 | reply. Our job is to fill in all the fields of the TCP and IP
|
---|
| 1822 | headers before calculating the checksum and finally send the
|
---|
| 1823 | packet. */
|
---|
[262] | 1824 | tcp_send:
|
---|
[101] | 1825 | BUF->ackno[0] = uip_connr->rcv_nxt[0];
|
---|
| 1826 | BUF->ackno[1] = uip_connr->rcv_nxt[1];
|
---|
| 1827 | BUF->ackno[2] = uip_connr->rcv_nxt[2];
|
---|
| 1828 | BUF->ackno[3] = uip_connr->rcv_nxt[3];
|
---|
| 1829 |
|
---|
| 1830 | BUF->seqno[0] = uip_connr->snd_nxt[0];
|
---|
| 1831 | BUF->seqno[1] = uip_connr->snd_nxt[1];
|
---|
| 1832 | BUF->seqno[2] = uip_connr->snd_nxt[2];
|
---|
| 1833 | BUF->seqno[3] = uip_connr->snd_nxt[3];
|
---|
| 1834 |
|
---|
| 1835 | BUF->proto = UIP_PROTO_TCP;
|
---|
| 1836 |
|
---|
| 1837 | BUF->srcport = uip_connr->lport;
|
---|
| 1838 | BUF->destport = uip_connr->rport;
|
---|
| 1839 |
|
---|
[262] | 1840 | uip_ipaddr_copy(&BUF->srcipaddr, &uip_hostaddr);
|
---|
| 1841 | uip_ipaddr_copy(&BUF->destipaddr, &uip_connr->ripaddr);
|
---|
[101] | 1842 |
|
---|
| 1843 | if(uip_connr->tcpstateflags & UIP_STOPPED) {
|
---|
| 1844 | /* If the connection has issued uip_stop(), we advertise a zero
|
---|
| 1845 | window so that the remote host will stop sending data. */
|
---|
| 1846 | BUF->wnd[0] = BUF->wnd[1] = 0;
|
---|
| 1847 | } else {
|
---|
| 1848 | BUF->wnd[0] = ((UIP_RECEIVE_WINDOW) >> 8);
|
---|
| 1849 | BUF->wnd[1] = ((UIP_RECEIVE_WINDOW) & 0xff);
|
---|
| 1850 | }
|
---|
| 1851 |
|
---|
| 1852 | tcp_send_noconn:
|
---|
| 1853 | BUF->ttl = UIP_TTL;
|
---|
| 1854 | #if UIP_CONF_IPV6
|
---|
| 1855 | /* For IPv6, the IP length field does not include the IPv6 IP header
|
---|
| 1856 | length. */
|
---|
| 1857 | BUF->len[0] = ((uip_len - UIP_IPH_LEN) >> 8);
|
---|
| 1858 | BUF->len[1] = ((uip_len - UIP_IPH_LEN) & 0xff);
|
---|
| 1859 | #else /* UIP_CONF_IPV6 */
|
---|
| 1860 | BUF->len[0] = (uip_len >> 8);
|
---|
| 1861 | BUF->len[1] = (uip_len & 0xff);
|
---|
| 1862 | #endif /* UIP_CONF_IPV6 */
|
---|
| 1863 |
|
---|
| 1864 | BUF->urgp[0] = BUF->urgp[1] = 0;
|
---|
| 1865 |
|
---|
| 1866 | /* Calculate TCP checksum. */
|
---|
| 1867 | BUF->tcpchksum = 0;
|
---|
| 1868 | BUF->tcpchksum = ~(uip_tcpchksum());
|
---|
| 1869 |
|
---|
| 1870 | ip_send_nolen:
|
---|
| 1871 | #if UIP_CONF_IPV6
|
---|
| 1872 | BUF->vtc = 0x60;
|
---|
| 1873 | BUF->tcflow = 0x00;
|
---|
| 1874 | BUF->flow = 0x00;
|
---|
| 1875 | #else /* UIP_CONF_IPV6 */
|
---|
| 1876 | BUF->vhl = 0x45;
|
---|
| 1877 | BUF->tos = 0;
|
---|
| 1878 | BUF->ipoffset[0] = BUF->ipoffset[1] = 0;
|
---|
| 1879 | ++ipid;
|
---|
| 1880 | BUF->ipid[0] = ipid >> 8;
|
---|
| 1881 | BUF->ipid[1] = ipid & 0xff;
|
---|
| 1882 | /* Calculate IP checksum. */
|
---|
| 1883 | BUF->ipchksum = 0;
|
---|
| 1884 | BUF->ipchksum = ~(uip_ipchksum());
|
---|
| 1885 | DEBUG_PRINTF("uip ip_send_nolen: chkecum 0x%04x\n", uip_ipchksum());
|
---|
| 1886 | #endif /* UIP_CONF_IPV6 */
|
---|
| 1887 | UIP_STAT(++uip_stat.tcp.sent);
|
---|
[262] | 1888 | #if UIP_CONF_IPV6
|
---|
[101] | 1889 | send:
|
---|
[262] | 1890 | #endif /* UIP_CONF_IPV6 */
|
---|
[101] | 1891 | DEBUG_PRINTF("Sending packet with length %d (%d)\n", uip_len,
|
---|
| 1892 | (BUF->len[0] << 8) | BUF->len[1]);
|
---|
| 1893 |
|
---|
| 1894 | UIP_STAT(++uip_stat.ip.sent);
|
---|
| 1895 | /* Return and let the caller do the actual transmission. */
|
---|
| 1896 | uip_flags = 0;
|
---|
| 1897 | return;
|
---|
[262] | 1898 |
|
---|
[101] | 1899 | drop:
|
---|
| 1900 | uip_len = 0;
|
---|
| 1901 | uip_flags = 0;
|
---|
| 1902 | return;
|
---|
| 1903 | }
|
---|
| 1904 | /*---------------------------------------------------------------------------*/
|
---|
[158] | 1905 | uint16_t
|
---|
[262] | 1906 | uip_htons(uint16_t val)
|
---|
[101] | 1907 | {
|
---|
[262] | 1908 | return UIP_HTONS(val);
|
---|
[101] | 1909 | }
|
---|
| 1910 | /*---------------------------------------------------------------------------*/
|
---|
| 1911 | void
|
---|
| 1912 | uip_send(const void *data, int len)
|
---|
| 1913 | {
|
---|
| 1914 | if(len > 0) {
|
---|
| 1915 | uip_slen = len;
|
---|
| 1916 | if(data != uip_sappdata) {
|
---|
| 1917 | memcpy(uip_sappdata, (data), uip_slen);
|
---|
| 1918 | }
|
---|
| 1919 | }
|
---|
| 1920 | }
|
---|
| 1921 | /** @} */
|
---|