1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * arping.c - Ping hosts by ARP requests/replies
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4 | *
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5 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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6 | *
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7 | * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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8 | * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
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9 | */
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10 |
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11 | #include <sys/ioctl.h>
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12 | #include <signal.h>
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13 |
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14 | #include <errno.h>
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15 | #include <stdlib.h>
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16 | #include <string.h>
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17 | #include <unistd.h>
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18 |
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19 | #include <arpa/inet.h>
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20 | #include <net/if.h>
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21 | #include <netinet/ether.h>
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22 | #include <netpacket/packet.h>
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23 |
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24 | #include "busybox.h"
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25 |
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26 | static struct in_addr src;
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27 | static struct in_addr dst;
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28 | static struct sockaddr_ll me;
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29 | static struct sockaddr_ll he;
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30 | static struct timeval last;
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31 |
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32 | enum cfg_e {
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33 | dad = 1,
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34 | unsolicited = 2,
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35 | advert = 4,
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36 | quiet = 8,
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37 | quit_on_reply = 16,
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38 | broadcast_only = 32,
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39 | unicasting = 64
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40 | };
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41 | static int cfg;
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42 |
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43 | static int s;
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44 | static int count = -1;
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45 | static int timeout;
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46 | static int sent;
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47 | static int brd_sent;
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48 | static int received;
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49 | static int brd_recv;
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50 | static int req_recv;
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51 |
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52 |
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53 | #define MS_TDIFF(tv1,tv2) ( ((tv1).tv_sec-(tv2).tv_sec)*1000 + \
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54 | ((tv1).tv_usec-(tv2).tv_usec)/1000 )
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55 | #if 0
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56 | static void set_signal(int signo, void (*handler) (void))
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57 | {
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58 | struct sigaction sa;
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59 |
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60 | memset(&sa, 0, sizeof(sa));
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61 | sa.sa_handler = (void (*)(int)) handler;
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62 | sa.sa_flags = SA_RESTART;
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63 | sigaction(signo, &sa, NULL);
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64 | }
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65 | #endif
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66 |
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67 | static int send_pack(int sock, struct in_addr *src_addr,
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68 | struct in_addr *dst_addr, struct sockaddr_ll *ME,
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69 | struct sockaddr_ll *HE)
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70 | {
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71 | int err;
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72 | struct timeval now;
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73 | RESERVE_CONFIG_UBUFFER(buf, 256);
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74 | struct arphdr *ah = (struct arphdr *) buf;
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75 | unsigned char *p = (unsigned char *) (ah + 1);
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76 |
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77 | ah->ar_hrd = htons(ME->sll_hatype);
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78 | ah->ar_hrd = htons(ARPHRD_ETHER);
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79 | ah->ar_pro = htons(ETH_P_IP);
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80 | ah->ar_hln = ME->sll_halen;
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81 | ah->ar_pln = 4;
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82 | ah->ar_op = cfg&advert ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
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83 |
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84 | memcpy(p, &ME->sll_addr, ah->ar_hln);
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85 | p += ME->sll_halen;
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86 |
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87 | memcpy(p, src_addr, 4);
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88 | p += 4;
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89 |
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90 | if (cfg&advert)
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91 | memcpy(p, &ME->sll_addr, ah->ar_hln);
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92 | else
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93 | memcpy(p, &HE->sll_addr, ah->ar_hln);
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94 | p += ah->ar_hln;
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95 |
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96 | memcpy(p, dst_addr, 4);
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97 | p += 4;
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98 |
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99 | gettimeofday(&now, NULL);
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100 | err = sendto(sock, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
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101 | if (err == p - buf) {
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102 | last = now;
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103 | sent++;
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104 | if (!(cfg&unicasting))
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105 | brd_sent++;
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106 | }
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107 | RELEASE_CONFIG_BUFFER(buf);
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108 | return err;
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109 | }
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110 |
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111 | static void finish(void)
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112 | {
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113 | if (!(cfg&quiet)) {
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114 | printf("Sent %d probes (%d broadcast(s))\n"
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115 | "Received %d repl%s",
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116 | sent, brd_sent,
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117 | received, (received > 1) ? "ies" : "y");
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118 | if (brd_recv || req_recv) {
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119 | printf(" (");
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120 | if (req_recv)
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121 | printf("%d request(s)", req_recv);
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122 | if (brd_recv)
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123 | printf("%s%d broadcast(s)", req_recv ? ", " : "", brd_recv);
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124 | putchar(')');
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125 | }
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126 | putchar('\n');
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127 | fflush(stdout);
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128 | }
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129 | if (cfg&dad)
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130 | exit(!!received);
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131 | if (cfg&unsolicited)
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132 | exit(0);
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133 | exit(!received);
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134 | }
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135 |
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136 | static void catcher(void)
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137 | {
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138 | struct timeval tv;
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139 | static struct timeval start;
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140 |
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141 | gettimeofday(&tv, NULL);
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142 |
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143 | if (start.tv_sec == 0)
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144 | start = tv;
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145 |
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146 | if (count-- == 0
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147 | || (timeout && MS_TDIFF(tv, start) > timeout * 1000 + 500))
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148 | finish();
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149 |
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150 | if (last.tv_sec == 0 || MS_TDIFF(tv, last) > 500) {
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151 | send_pack(s, &src, &dst, &me, &he);
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152 | if (count == 0 && cfg&unsolicited)
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153 | finish();
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154 | }
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155 | alarm(1);
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156 | }
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157 |
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158 | static int recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
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159 | {
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160 | struct arphdr *ah = (struct arphdr *) buf;
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161 | unsigned char *p = (unsigned char *) (ah + 1);
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162 | struct in_addr src_ip, dst_ip;
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163 |
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164 | /* Filter out wild packets */
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165 | if (FROM->sll_pkttype != PACKET_HOST &&
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166 | FROM->sll_pkttype != PACKET_BROADCAST &&
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167 | FROM->sll_pkttype != PACKET_MULTICAST)
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168 | return 0;
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169 |
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170 | /* Only these types are recognised */
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171 | if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
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172 | return 0;
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173 |
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174 | /* ARPHRD check and this darned FDDI hack here :-( */
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175 | if (ah->ar_hrd != htons(FROM->sll_hatype) &&
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176 | (FROM->sll_hatype != ARPHRD_FDDI
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177 | || ah->ar_hrd != htons(ARPHRD_ETHER)))
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178 | return 0;
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179 |
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180 | /* Protocol must be IP. */
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181 | if (ah->ar_pro != htons(ETH_P_IP))
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182 | return 0;
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183 | if (ah->ar_pln != 4)
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184 | return 0;
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185 | if (ah->ar_hln != me.sll_halen)
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186 | return 0;
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187 | if (len < sizeof(*ah) + 2 * (4 + ah->ar_hln))
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188 | return 0;
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189 | memcpy(&src_ip, p + ah->ar_hln, 4);
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190 | memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
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191 | if (!(cfg&dad)) {
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192 | if (src_ip.s_addr != dst.s_addr)
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193 | return 0;
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194 | if (src.s_addr != dst_ip.s_addr)
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195 | return 0;
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196 | if (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln))
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197 | return 0;
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198 | } else {
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199 | /* DAD packet was:
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200 | src_ip = 0 (or some src)
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201 | src_hw = ME
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202 | dst_ip = tested address
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203 | dst_hw = <unspec>
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204 |
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205 | We fail, if receive request/reply with:
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206 | src_ip = tested_address
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207 | src_hw != ME
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208 | if src_ip in request was not zero, check
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209 | also that it matches to dst_ip, otherwise
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210 | dst_ip/dst_hw do not matter.
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211 | */
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212 | if (src_ip.s_addr != dst.s_addr)
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213 | return 0;
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214 | if (memcmp(p, &me.sll_addr, me.sll_halen) == 0)
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215 | return 0;
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216 | if (src.s_addr && src.s_addr != dst_ip.s_addr)
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217 | return 0;
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218 | }
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219 | if (!(cfg&quiet)) {
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220 | int s_printed = 0;
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221 | struct timeval tv;
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222 |
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223 | gettimeofday(&tv, NULL);
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224 |
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225 | printf("%s %s from %s [%s]",
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226 | FROM->sll_pkttype == PACKET_HOST ? "Unicast" : "Broadcast",
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227 | ah->ar_op == htons(ARPOP_REPLY) ? "reply" : "request",
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228 | inet_ntoa(src_ip),
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229 | ether_ntoa((struct ether_addr *) p));
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230 | if (dst_ip.s_addr != src.s_addr) {
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231 | printf("for %s ", inet_ntoa(dst_ip));
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232 | s_printed = 1;
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233 | }
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234 | if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
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235 | if (!s_printed)
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236 | printf("for ");
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237 | printf("[%s]",
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238 | ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
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239 | }
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240 |
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241 | if (last.tv_sec) {
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242 | long usecs = (tv.tv_sec - last.tv_sec) * 1000000 +
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243 | tv.tv_usec - last.tv_usec;
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244 | long msecs = (usecs + 500) / 1000;
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245 |
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246 | usecs -= msecs * 1000 - 500;
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247 | printf(" %ld.%03ldms\n", msecs, usecs);
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248 | } else {
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249 | printf(" UNSOLICITED?\n");
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250 | }
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251 | fflush(stdout);
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252 | }
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253 | received++;
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254 | if (FROM->sll_pkttype != PACKET_HOST)
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255 | brd_recv++;
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256 | if (ah->ar_op == htons(ARPOP_REQUEST))
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257 | req_recv++;
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258 | if (cfg&quit_on_reply)
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259 | finish();
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260 | if (!(cfg&broadcast_only)) {
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261 | memcpy(he.sll_addr, p, me.sll_halen);
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262 | cfg |= unicasting;
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263 | }
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264 | return 1;
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265 | }
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266 |
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267 | int arping_main(int argc, char **argv)
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268 | {
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269 | char *device = "eth0";
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270 | int ifindex;
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271 | char *source = NULL;
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272 | char *target;
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273 |
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274 | s = socket(PF_PACKET, SOCK_DGRAM, 0);
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275 | ifindex = errno;
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276 |
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277 | // Drop suid root privileges
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278 | xsetuid(getuid());
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279 |
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280 | {
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281 | unsigned long opt;
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282 | char *_count, *_timeout, *_device;
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283 |
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284 | /* Dad also sets quit_on_reply.
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285 | * Advert also sets unsolicited.
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286 | */
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287 | bb_opt_complementally = "Df:AU";
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288 | opt = bb_getopt_ulflags(argc, argv, "DUAqfbc:w:i:s:",
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289 | &_count, &_timeout, &_device);
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290 | cfg |= opt & 63; /* set respective flags */
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291 | if (opt & 64) /* count */
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292 | count = atoi(_count);
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293 | if (opt & 128) /* timeout */
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294 | timeout = atoi(_timeout);
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295 | if (opt & 256) { /* interface */
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296 | if (strlen(_device) > IF_NAMESIZE) {
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297 | bb_error_msg_and_die("Interface name `%s' must be less than %d",
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298 | _device, IF_NAMESIZE);
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299 | }
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300 | device = _device;
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301 | }
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302 | if (opt & 512) /* source */
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303 | source = optarg;
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304 | }
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305 | argc -= optind;
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306 | argv += optind;
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307 |
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308 | if (argc != 1)
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309 | bb_show_usage();
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310 |
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311 | target = *argv;
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312 |
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313 |
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314 | if (s < 0) {
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315 | bb_default_error_retval = ifindex;
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316 | bb_perror_msg_and_die("socket");
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317 | }
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318 | bb_default_error_retval = 2;
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319 |
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320 | {
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321 | struct ifreq ifr;
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322 |
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323 | memset(&ifr, 0, sizeof(ifr));
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324 | strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
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325 | if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
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326 | bb_error_msg_and_die("Interface %s not found", device);
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327 | }
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328 | ifindex = ifr.ifr_ifindex;
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329 |
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330 | if (ioctl(s, SIOCGIFFLAGS, (char *) &ifr)) {
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331 | bb_error_msg_and_die("SIOCGIFFLAGS");
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332 | }
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333 | if (!(ifr.ifr_flags & IFF_UP)) {
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334 | bb_error_msg_and_die("Interface %s is down", device);
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335 | }
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336 | if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
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337 | bb_error_msg("Interface %s is not ARPable", device);
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338 | exit(cfg&dad ? 0 : 2);
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339 | }
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340 | }
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341 |
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342 | if (!inet_aton(target, &dst)) {
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343 | struct hostent *hp;
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344 |
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345 | hp = gethostbyname2(target, AF_INET);
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346 | if (!hp) {
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347 | bb_error_msg_and_die("invalid or unknown target %s", target);
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348 | }
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349 | memcpy(&dst, hp->h_addr, 4);
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350 | }
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351 |
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352 | if (source && !inet_aton(source, &src)) {
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353 | bb_error_msg_and_die("invalid source address %s", source);
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354 | }
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355 |
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356 | if (!(cfg&dad) && cfg&unsolicited && src.s_addr == 0)
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357 | src = dst;
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358 |
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359 | if (!(cfg&dad) || src.s_addr) {
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360 | struct sockaddr_in saddr;
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361 | int probe_fd = socket(AF_INET, SOCK_DGRAM, 0); /* maybe use bb_xsocket? */
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362 |
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363 | if (probe_fd < 0) {
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364 | bb_error_msg_and_die("socket");
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365 | }
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366 | if (device) {
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367 | if (setsockopt
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368 | (probe_fd, SOL_SOCKET, SO_BINDTODEVICE, device,
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369 | strlen(device) + 1) == -1)
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370 | bb_error_msg("WARNING: interface %s is ignored", device);
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371 | }
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372 | memset(&saddr, 0, sizeof(saddr));
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373 | saddr.sin_family = AF_INET;
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374 | if (src.s_addr) {
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375 | saddr.sin_addr = src;
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376 | if (bind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr)) == -1) {
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377 | bb_error_msg_and_die("bind");
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378 | }
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379 | } else if (!(cfg&dad)) {
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380 | int on = 1;
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381 | socklen_t alen = sizeof(saddr);
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382 |
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383 | saddr.sin_port = htons(1025);
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384 | saddr.sin_addr = dst;
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385 |
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386 | if (setsockopt
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387 | (probe_fd, SOL_SOCKET, SO_DONTROUTE, (char *) &on,
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388 | sizeof(on)) == -1)
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389 | bb_perror_msg("WARNING: setsockopt(SO_DONTROUTE)");
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390 | if (connect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr))
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391 | == -1) {
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392 | bb_error_msg_and_die("connect");
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393 | }
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394 | if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) ==
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395 | -1) {
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396 | bb_error_msg_and_die("getsockname");
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397 | }
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398 | src = saddr.sin_addr;
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399 | }
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400 | close(probe_fd);
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401 | };
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402 |
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403 | me.sll_family = AF_PACKET;
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404 | me.sll_ifindex = ifindex;
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405 | me.sll_protocol = htons(ETH_P_ARP);
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406 | if (bind(s, (struct sockaddr *) &me, sizeof(me)) == -1) {
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407 | bb_error_msg_and_die("bind");
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408 | }
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409 |
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410 | {
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411 | socklen_t alen = sizeof(me);
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412 |
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413 | if (getsockname(s, (struct sockaddr *) &me, &alen) == -1) {
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414 | bb_error_msg_and_die("getsockname");
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415 | }
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416 | }
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417 | if (me.sll_halen == 0) {
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418 | bb_error_msg("Interface \"%s\" is not ARPable (no ll address)", device);
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419 | exit(cfg&dad ? 0 : 2);
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420 | }
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421 | he = me;
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422 | memset(he.sll_addr, -1, he.sll_halen);
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423 |
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424 | if (!(cfg&quiet)) {
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425 | printf("ARPING to %s from %s via %s\n",
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426 | inet_ntoa(dst), inet_ntoa(src),
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427 | device ? device : "unknown");
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428 | }
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429 |
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430 | if (!src.s_addr && !(cfg&dad)) {
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431 | bb_error_msg_and_die("no src address in the non-DAD mode");
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432 | }
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433 |
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434 | {
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435 | struct sigaction sa;
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436 |
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437 | memset(&sa, 0, sizeof(sa));
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438 | sa.sa_flags = SA_RESTART;
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439 |
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440 | sa.sa_handler = (void (*)(int)) finish;
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441 | sigaction(SIGINT, &sa, NULL);
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442 |
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443 | sa.sa_handler = (void (*)(int)) catcher;
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444 | sigaction(SIGALRM, &sa, NULL);
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445 | }
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446 |
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447 | catcher();
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448 |
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449 | while (1) {
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450 | sigset_t sset, osset;
|
---|
451 | RESERVE_CONFIG_UBUFFER(packet, 4096);
|
---|
452 | struct sockaddr_ll from;
|
---|
453 | socklen_t alen = sizeof(from);
|
---|
454 | int cc;
|
---|
455 |
|
---|
456 | if ((cc = recvfrom(s, packet, 4096, 0,
|
---|
457 | (struct sockaddr *) &from, &alen)) < 0) {
|
---|
458 | perror("recvfrom");
|
---|
459 | continue;
|
---|
460 | }
|
---|
461 | sigemptyset(&sset);
|
---|
462 | sigaddset(&sset, SIGALRM);
|
---|
463 | sigaddset(&sset, SIGINT);
|
---|
464 | sigprocmask(SIG_BLOCK, &sset, &osset);
|
---|
465 | recv_pack(packet, cc, &from);
|
---|
466 | sigprocmask(SIG_SETMASK, &osset, NULL);
|
---|
467 | RELEASE_CONFIG_BUFFER(packet);
|
---|
468 | }
|
---|
469 | }
|
---|