1 | /**
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2 | * @file
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3 | *
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4 | * IPv6 version of ICMP, as per RFC 4443.
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5 | */
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6 |
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7 | /*
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8 | * Copyright (c) 2010 Inico Technologies Ltd.
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9 | * All rights reserved.
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10 | *
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11 | * Redistribution and use in source and binary forms, with or without modification,
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12 | * are permitted provided that the following conditions are met:
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13 | *
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14 | * 1. Redistributions of source code must retain the above copyright notice,
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15 | * this list of conditions and the following disclaimer.
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16 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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17 | * this list of conditions and the following disclaimer in the documentation
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18 | * and/or other materials provided with the distribution.
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19 | * 3. The name of the author may not be used to endorse or promote products
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20 | * derived from this software without specific prior written permission.
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21 | *
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22 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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23 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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24 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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25 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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26 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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27 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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30 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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31 | * OF SUCH DAMAGE.
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32 | *
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33 | * This file is part of the lwIP TCP/IP stack.
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34 | *
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35 | * Author: Ivan Delamer <delamer@inicotech.com>
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36 | *
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37 | *
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38 | * Please coordinate changes and requests with Ivan Delamer
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39 | * <delamer@inicotech.com>
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40 | */
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41 |
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42 | #include "lwip/opt.h"
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43 |
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44 | #if LWIP_ICMP6 && LWIP_IPV6 /* don't build if not configured for use in lwipopts.h */
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45 |
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46 | #include "lwip/icmp6.h"
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47 | #include "lwip/prot/icmp6.h"
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48 | #include "lwip/ip6.h"
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49 | #include "lwip/ip6_addr.h"
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50 | #include "lwip/inet_chksum.h"
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51 | #include "lwip/pbuf.h"
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52 | #include "lwip/netif.h"
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53 | #include "lwip/nd6.h"
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54 | #include "lwip/mld6.h"
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55 | #include "lwip/ip.h"
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56 | #include "lwip/stats.h"
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57 |
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58 | #include <string.h>
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59 |
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60 | #if LWIP_ICMP6_DATASIZE == 0
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61 | #undef LWIP_ICMP6_DATASIZE
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62 | #define LWIP_ICMP6_DATASIZE 8
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63 | #endif
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64 |
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65 | /* Forward declarations */
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66 | static void icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type);
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67 | static void icmp6_send_response_with_addrs(struct pbuf *p, u8_t code, u32_t data,
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68 | u8_t type, const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr);
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69 | static void icmp6_send_response_with_addrs_and_netif(struct pbuf *p, u8_t code, u32_t data,
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70 | u8_t type, const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr, struct netif *netif);
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71 |
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72 |
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73 | /**
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74 | * Process an input ICMPv6 message. Called by ip6_input.
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75 | *
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76 | * Will generate a reply for echo requests. Other messages are forwarded
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77 | * to nd6_input, or mld6_input.
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78 | *
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79 | * @param p the mld packet, p->payload pointing to the icmpv6 header
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80 | * @param inp the netif on which this packet was received
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81 | */
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82 | void
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83 | icmp6_input(struct pbuf *p, struct netif *inp)
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84 | {
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85 | struct icmp6_hdr *icmp6hdr;
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86 | struct pbuf *r;
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87 | const ip6_addr_t *reply_src;
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88 |
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89 | ICMP6_STATS_INC(icmp6.recv);
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90 |
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91 | /* Check that ICMPv6 header fits in payload */
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92 | if (p->len < sizeof(struct icmp6_hdr)) {
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93 | /* drop short packets */
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94 | pbuf_free(p);
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95 | ICMP6_STATS_INC(icmp6.lenerr);
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96 | ICMP6_STATS_INC(icmp6.drop);
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97 | return;
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98 | }
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99 |
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100 | icmp6hdr = (struct icmp6_hdr *)p->payload;
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101 |
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102 | #if CHECKSUM_CHECK_ICMP6
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103 | IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_CHECK_ICMP6) {
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104 | if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len, ip6_current_src_addr(),
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105 | ip6_current_dest_addr()) != 0) {
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106 | /* Checksum failed */
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107 | pbuf_free(p);
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108 | ICMP6_STATS_INC(icmp6.chkerr);
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109 | ICMP6_STATS_INC(icmp6.drop);
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110 | return;
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111 | }
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112 | }
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113 | #endif /* CHECKSUM_CHECK_ICMP6 */
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114 |
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115 | switch (icmp6hdr->type) {
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116 | case ICMP6_TYPE_NA: /* Neighbor advertisement */
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117 | case ICMP6_TYPE_NS: /* Neighbor solicitation */
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118 | case ICMP6_TYPE_RA: /* Router advertisement */
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119 | case ICMP6_TYPE_RD: /* Redirect */
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120 | case ICMP6_TYPE_PTB: /* Packet too big */
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121 | nd6_input(p, inp);
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122 | return;
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123 | case ICMP6_TYPE_RS:
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124 | #if LWIP_IPV6_FORWARD
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125 | /* @todo implement router functionality */
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126 | #endif
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127 | break;
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128 | #if LWIP_IPV6_MLD
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129 | case ICMP6_TYPE_MLQ:
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130 | case ICMP6_TYPE_MLR:
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131 | case ICMP6_TYPE_MLD:
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132 | mld6_input(p, inp);
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133 | return;
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134 | #endif
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135 | case ICMP6_TYPE_EREQ:
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136 | #if !LWIP_MULTICAST_PING
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137 | /* multicast destination address? */
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138 | if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
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139 | /* drop */
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140 | pbuf_free(p);
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141 | ICMP6_STATS_INC(icmp6.drop);
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142 | return;
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143 | }
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144 | #endif /* LWIP_MULTICAST_PING */
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145 |
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146 | /* Allocate reply. */
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147 | r = pbuf_alloc(PBUF_IP, p->tot_len, PBUF_RAM);
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148 | if (r == NULL) {
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149 | /* drop */
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150 | pbuf_free(p);
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151 | ICMP6_STATS_INC(icmp6.memerr);
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152 | return;
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153 | }
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154 |
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155 | /* Copy echo request. */
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156 | if (pbuf_copy(r, p) != ERR_OK) {
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157 | /* drop */
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158 | pbuf_free(p);
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159 | pbuf_free(r);
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160 | ICMP6_STATS_INC(icmp6.err);
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161 | return;
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162 | }
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163 |
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164 | /* Determine reply source IPv6 address. */
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165 | #if LWIP_MULTICAST_PING
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166 | if (ip6_addr_ismulticast(ip6_current_dest_addr())) {
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167 | reply_src = ip_2_ip6(ip6_select_source_address(inp, ip6_current_src_addr()));
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168 | if (reply_src == NULL) {
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169 | /* drop */
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170 | pbuf_free(p);
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171 | pbuf_free(r);
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172 | ICMP6_STATS_INC(icmp6.rterr);
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173 | return;
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174 | }
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175 | }
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176 | else
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177 | #endif /* LWIP_MULTICAST_PING */
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178 | {
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179 | reply_src = ip6_current_dest_addr();
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180 | }
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181 |
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182 | /* Set fields in reply. */
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183 | ((struct icmp6_echo_hdr *)(r->payload))->type = ICMP6_TYPE_EREP;
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184 | ((struct icmp6_echo_hdr *)(r->payload))->chksum = 0;
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185 | #if CHECKSUM_GEN_ICMP6
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186 | IF__NETIF_CHECKSUM_ENABLED(inp, NETIF_CHECKSUM_GEN_ICMP6) {
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187 | ((struct icmp6_echo_hdr *)(r->payload))->chksum = ip6_chksum_pseudo(r,
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188 | IP6_NEXTH_ICMP6, r->tot_len, reply_src, ip6_current_src_addr());
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189 | }
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190 | #endif /* CHECKSUM_GEN_ICMP6 */
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191 |
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192 | /* Send reply. */
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193 | ICMP6_STATS_INC(icmp6.xmit);
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194 | ip6_output_if(r, reply_src, ip6_current_src_addr(),
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195 | LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, inp);
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196 | pbuf_free(r);
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197 |
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198 | break;
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199 | default:
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200 | ICMP6_STATS_INC(icmp6.proterr);
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201 | ICMP6_STATS_INC(icmp6.drop);
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202 | break;
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203 | }
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204 |
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205 | pbuf_free(p);
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206 | }
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207 |
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208 |
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209 | /**
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210 | * Send an icmpv6 'destination unreachable' packet.
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211 | *
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212 | * This function must be used only in direct response to a packet that is being
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213 | * received right now. Otherwise, address zones would be lost.
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214 | *
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215 | * @param p the input packet for which the 'unreachable' should be sent,
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216 | * p->payload pointing to the IPv6 header
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217 | * @param c ICMPv6 code for the unreachable type
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218 | */
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219 | void
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220 | icmp6_dest_unreach(struct pbuf *p, enum icmp6_dur_code c)
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221 | {
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222 | icmp6_send_response(p, c, 0, ICMP6_TYPE_DUR);
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223 | }
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224 |
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225 | /**
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226 | * Send an icmpv6 'packet too big' packet.
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227 | *
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228 | * This function must be used only in direct response to a packet that is being
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229 | * received right now. Otherwise, address zones would be lost.
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230 | *
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231 | * @param p the input packet for which the 'packet too big' should be sent,
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232 | * p->payload pointing to the IPv6 header
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233 | * @param mtu the maximum mtu that we can accept
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234 | */
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235 | void
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236 | icmp6_packet_too_big(struct pbuf *p, u32_t mtu)
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237 | {
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238 | icmp6_send_response(p, 0, mtu, ICMP6_TYPE_PTB);
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239 | }
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240 |
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241 | /**
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242 | * Send an icmpv6 'time exceeded' packet.
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243 | *
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244 | * This function must be used only in direct response to a packet that is being
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245 | * received right now. Otherwise, address zones would be lost.
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246 | *
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247 | * @param p the input packet for which the 'time exceeded' should be sent,
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248 | * p->payload pointing to the IPv6 header
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249 | * @param c ICMPv6 code for the time exceeded type
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250 | */
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251 | void
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252 | icmp6_time_exceeded(struct pbuf *p, enum icmp6_te_code c)
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253 | {
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254 | icmp6_send_response(p, c, 0, ICMP6_TYPE_TE);
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255 | }
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256 |
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257 | /**
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258 | * Send an icmpv6 'time exceeded' packet, with explicit source and destination
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259 | * addresses.
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260 | *
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261 | * This function may be used to send a response sometime after receiving the
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262 | * packet for which this response is meant. The provided source and destination
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263 | * addresses are used primarily to retain their zone information.
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264 | *
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265 | * @param p the input packet for which the 'time exceeded' should be sent,
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266 | * p->payload pointing to the IPv6 header
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267 | * @param c ICMPv6 code for the time exceeded type
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268 | * @param src_addr source address of the original packet, with zone information
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269 | * @param dest_addr destination address of the original packet, with zone
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270 | * information
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271 | */
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272 | void
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273 | icmp6_time_exceeded_with_addrs(struct pbuf *p, enum icmp6_te_code c,
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274 | const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr)
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275 | {
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276 | icmp6_send_response_with_addrs(p, c, 0, ICMP6_TYPE_TE, src_addr, dest_addr);
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277 | }
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278 |
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279 | /**
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280 | * Send an icmpv6 'parameter problem' packet.
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281 | *
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282 | * This function must be used only in direct response to a packet that is being
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283 | * received right now. Otherwise, address zones would be lost and the calculated
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284 | * offset would be wrong (calculated against ip6_current_header()).
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285 | *
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286 | * @param p the input packet for which the 'param problem' should be sent,
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287 | * p->payload pointing to the IP header
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288 | * @param c ICMPv6 code for the param problem type
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289 | * @param pointer the pointer to the byte where the parameter is found
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290 | */
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291 | void
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292 | icmp6_param_problem(struct pbuf *p, enum icmp6_pp_code c, const void *pointer)
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293 | {
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294 | u32_t pointer_u32 = (u32_t)((const u8_t *)pointer - (const u8_t *)ip6_current_header());
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295 | icmp6_send_response(p, c, pointer_u32, ICMP6_TYPE_PP);
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296 | }
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297 |
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298 | /**
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299 | * Send an ICMPv6 packet in response to an incoming packet.
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300 | * The packet is sent *to* ip_current_src_addr() on ip_current_netif().
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301 | *
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302 | * @param p the input packet for which the response should be sent,
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303 | * p->payload pointing to the IPv6 header
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304 | * @param code Code of the ICMPv6 header
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305 | * @param data Additional 32-bit parameter in the ICMPv6 header
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306 | * @param type Type of the ICMPv6 header
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307 | */
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308 | static void
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309 | icmp6_send_response(struct pbuf *p, u8_t code, u32_t data, u8_t type)
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310 | {
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311 | const struct ip6_addr *reply_src, *reply_dest;
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312 | struct netif *netif = ip_current_netif();
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313 |
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314 | LWIP_ASSERT("icmpv6 packet not a direct response", netif != NULL);
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315 | reply_dest = ip6_current_src_addr();
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316 |
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317 | /* Select an address to use as source. */
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318 | reply_src = ip_2_ip6(ip6_select_source_address(netif, reply_dest));
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319 | if (reply_src == NULL) {
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320 | ICMP6_STATS_INC(icmp6.rterr);
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321 | return;
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322 | }
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323 | icmp6_send_response_with_addrs_and_netif(p, code, data, type, reply_src, reply_dest, netif);
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324 | }
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325 |
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326 | /**
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327 | * Send an ICMPv6 packet in response to an incoming packet.
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328 | *
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329 | * Call this function if the packet is NOT sent as a direct response to an
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330 | * incoming packet, but rather sometime later (e.g. for a fragment reassembly
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331 | * timeout). The caller must provide the zoned source and destination addresses
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332 | * from the original packet with the src_addr and dest_addr parameters. The
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333 | * reason for this approach is that while the addresses themselves are part of
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334 | * the original packet, their zone information is not, thus possibly resulting
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335 | * in a link-local response being sent over the wrong link.
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336 | *
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337 | * @param p the input packet for which the response should be sent,
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338 | * p->payload pointing to the IPv6 header
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339 | * @param code Code of the ICMPv6 header
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340 | * @param data Additional 32-bit parameter in the ICMPv6 header
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341 | * @param type Type of the ICMPv6 header
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342 | * @param src_addr original source address
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343 | * @param dest_addr original destination address
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344 | */
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345 | static void
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346 | icmp6_send_response_with_addrs(struct pbuf *p, u8_t code, u32_t data, u8_t type,
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347 | const ip6_addr_t *src_addr, const ip6_addr_t *dest_addr)
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348 | {
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349 | const struct ip6_addr *reply_src, *reply_dest;
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350 | struct netif *netif;
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351 |
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352 | /* Get the destination address and netif for this ICMP message. */
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353 | LWIP_ASSERT("must provide both source and destination", src_addr != NULL);
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354 | LWIP_ASSERT("must provide both source and destination", dest_addr != NULL);
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355 |
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356 | /* Special case, as ip6_current_xxx is either NULL, or points
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357 | to a different packet than the one that expired. */
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358 | IP6_ADDR_ZONECHECK(src_addr);
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359 | IP6_ADDR_ZONECHECK(dest_addr);
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360 | /* Swap source and destination for the reply. */
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361 | reply_dest = src_addr;
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362 | reply_src = dest_addr;
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363 | netif = ip6_route(reply_src, reply_dest);
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364 | if (netif == NULL) {
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365 | ICMP6_STATS_INC(icmp6.rterr);
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366 | return;
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367 | }
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368 | icmp6_send_response_with_addrs_and_netif(p, code, data, type, reply_src,
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369 | reply_dest, netif);
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370 | }
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371 |
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372 | /**
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373 | * Send an ICMPv6 packet (with srd/dst address and netif given).
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374 | *
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375 | * @param p the input packet for which the response should be sent,
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376 | * p->payload pointing to the IPv6 header
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377 | * @param code Code of the ICMPv6 header
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378 | * @param data Additional 32-bit parameter in the ICMPv6 header
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379 | * @param type Type of the ICMPv6 header
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380 | * @param reply_src source address of the packet to send
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381 | * @param reply_dest destination address of the packet to send
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382 | * @param netif netif to send the packet
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383 | */
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384 | static void
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385 | icmp6_send_response_with_addrs_and_netif(struct pbuf *p, u8_t code, u32_t data, u8_t type,
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386 | const ip6_addr_t *reply_src, const ip6_addr_t *reply_dest, struct netif *netif)
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387 | {
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388 | struct pbuf *q;
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389 | struct icmp6_hdr *icmp6hdr;
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390 |
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391 | /* ICMPv6 header + IPv6 header + data */
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392 | q = pbuf_alloc(PBUF_IP, sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE,
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393 | PBUF_RAM);
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394 | if (q == NULL) {
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395 | LWIP_DEBUGF(ICMP_DEBUG, ("icmp_time_exceeded: failed to allocate pbuf for ICMPv6 packet.\n"));
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396 | ICMP6_STATS_INC(icmp6.memerr);
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397 | return;
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398 | }
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399 | LWIP_ASSERT("check that first pbuf can hold icmp 6message",
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400 | (q->len >= (sizeof(struct icmp6_hdr) + IP6_HLEN + LWIP_ICMP6_DATASIZE)));
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401 |
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402 | icmp6hdr = (struct icmp6_hdr *)q->payload;
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403 | icmp6hdr->type = type;
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404 | icmp6hdr->code = code;
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405 | icmp6hdr->data = lwip_htonl(data);
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406 |
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407 | /* copy fields from original packet */
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408 | SMEMCPY((u8_t *)q->payload + sizeof(struct icmp6_hdr), (u8_t *)p->payload,
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409 | IP6_HLEN + LWIP_ICMP6_DATASIZE);
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410 |
|
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411 | /* calculate checksum */
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412 | icmp6hdr->chksum = 0;
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413 | #if CHECKSUM_GEN_ICMP6
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414 | IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_ICMP6) {
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415 | icmp6hdr->chksum = ip6_chksum_pseudo(q, IP6_NEXTH_ICMP6, q->tot_len,
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416 | reply_src, reply_dest);
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417 | }
|
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418 | #endif /* CHECKSUM_GEN_ICMP6 */
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419 |
|
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420 | ICMP6_STATS_INC(icmp6.xmit);
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421 | ip6_output_if(q, reply_src, reply_dest, LWIP_ICMP6_HL, 0, IP6_NEXTH_ICMP6, netif);
|
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422 | pbuf_free(q);
|
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423 | }
|
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424 |
|
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425 | #endif /* LWIP_ICMP6 && LWIP_IPV6 */
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