1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * arp.c - Manipulate the system ARP cache
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4 | *
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5 | * This program is free software; you can redistribute it and/or
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6 | * modify it under the terms of the GNU General Public License
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7 | * as published by the Free Software Foundation; either version
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8 | * 2 of the License, or (at your option) any later version.
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9 | *
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10 | * Author: Fred N. van Kempen, <waltje at uwalt.nl.mugnet.org>
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11 | * Busybox port: Paul van Gool <pvangool at mimotech.com>
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12 | *
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13 | * modified for getopt32 by Arne Bernin <arne [at] alamut.de>
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14 | */
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15 |
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16 | #include "libbb.h"
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17 | #include "inet_common.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 <net/if_arp.h>
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22 | #include <netinet/ether.h>
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23 | #include <netpacket/packet.h>
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24 |
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25 | #define DEBUG 0
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26 |
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27 | #define DFLT_AF "inet"
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28 | #define DFLT_HW "ether"
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29 |
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30 | enum {
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31 | ARP_OPT_A = (1 << 0),
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32 | ARP_OPT_p = (1 << 1),
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33 | ARP_OPT_H = (1 << 2),
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34 | ARP_OPT_t = (1 << 3),
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35 | ARP_OPT_i = (1 << 4),
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36 | ARP_OPT_a = (1 << 5),
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37 | ARP_OPT_d = (1 << 6),
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38 | ARP_OPT_n = (1 << 7), /* do not resolve addresses */
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39 | ARP_OPT_D = (1 << 8), /* HW-address is devicename */
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40 | ARP_OPT_s = (1 << 9),
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41 | ARP_OPT_v = (1 << 10) * DEBUG, /* debugging output flag */
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42 | };
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43 |
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44 | enum {
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45 | sockfd = 3, /* active socket descriptor */
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46 | };
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47 |
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48 | struct globals {
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49 | const struct aftype *ap; /* current address family */
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50 | const struct hwtype *hw; /* current hardware type */
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51 | const char *device; /* current device */
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52 | smallint hw_set; /* flag if hw-type was set (-H) */
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53 |
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54 | } FIX_ALIASING;
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55 | #define G (*(struct globals*)&bb_common_bufsiz1)
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56 | #define ap (G.ap )
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57 | #define hw (G.hw )
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58 | #define device (G.device )
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59 | #define hw_set (G.hw_set )
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60 | #define INIT_G() do { \
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61 | device = ""; \
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62 | } while (0)
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63 |
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64 |
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65 | static const char options[] ALIGN1 =
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66 | "pub\0"
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67 | "priv\0"
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68 | "temp\0"
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69 | "trail\0"
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70 | "dontpub\0"
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71 | "auto\0"
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72 | "dev\0"
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73 | "netmask\0";
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74 |
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75 | /* Delete an entry from the ARP cache. */
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76 | /* Called only from main, once */
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77 | static int arp_del(char **args)
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78 | {
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79 | char *host;
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80 | struct arpreq req;
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81 | struct sockaddr sa;
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82 | int flags = 0;
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83 | int err;
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84 |
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85 | memset(&req, 0, sizeof(req));
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86 |
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87 | /* Resolve the host name. */
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88 | host = *args;
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89 | if (ap->input(host, &sa) < 0) {
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90 | bb_herror_msg_and_die("%s", host);
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91 | }
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92 |
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93 | /* If a host has more than one address, use the correct one! */
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94 | memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
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95 |
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96 | if (hw_set)
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97 | req.arp_ha.sa_family = hw->type;
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98 |
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99 | req.arp_flags = ATF_PERM;
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100 | args++;
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101 | while (*args != NULL) {
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102 | switch (index_in_strings(options, *args)) {
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103 | case 0: /* "pub" */
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104 | flags |= 1;
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105 | args++;
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106 | break;
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107 | case 1: /* "priv" */
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108 | flags |= 2;
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109 | args++;
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110 | break;
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111 | case 2: /* "temp" */
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112 | req.arp_flags &= ~ATF_PERM;
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113 | args++;
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114 | break;
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115 | case 3: /* "trail" */
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116 | req.arp_flags |= ATF_USETRAILERS;
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117 | args++;
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118 | break;
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119 | case 4: /* "dontpub" */
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120 | #ifdef HAVE_ATF_DONTPUB
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121 | req.arp_flags |= ATF_DONTPUB;
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122 | #else
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123 | bb_error_msg("feature ATF_DONTPUB is not supported");
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124 | #endif
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125 | args++;
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126 | break;
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127 | case 5: /* "auto" */
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128 | #ifdef HAVE_ATF_MAGIC
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129 | req.arp_flags |= ATF_MAGIC;
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130 | #else
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131 | bb_error_msg("feature ATF_MAGIC is not supported");
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132 | #endif
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133 | args++;
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134 | break;
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135 | case 6: /* "dev" */
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136 | if (*++args == NULL)
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137 | bb_show_usage();
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138 | device = *args;
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139 | args++;
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140 | break;
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141 | case 7: /* "netmask" */
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142 | if (*++args == NULL)
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143 | bb_show_usage();
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144 | if (strcmp(*args, "255.255.255.255") != 0) {
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145 | host = *args;
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146 | if (ap->input(host, &sa) < 0) {
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147 | bb_herror_msg_and_die("%s", host);
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148 | }
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149 | memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
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150 | req.arp_flags |= ATF_NETMASK;
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151 | }
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152 | args++;
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153 | break;
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154 | default:
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155 | bb_show_usage();
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156 | break;
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157 | }
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158 | }
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159 | if (flags == 0)
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160 | flags = 3;
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161 |
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162 | strncpy(req.arp_dev, device, sizeof(req.arp_dev));
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163 |
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164 | err = -1;
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165 |
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166 | /* Call the kernel. */
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167 | if (flags & 2) {
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168 | if (option_mask32 & ARP_OPT_v)
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169 | bb_error_msg("SIOCDARP(nopub)");
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170 | err = ioctl(sockfd, SIOCDARP, &req);
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171 | if (err < 0) {
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172 | if (errno == ENXIO) {
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173 | if (flags & 1)
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174 | goto nopub;
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175 | printf("No ARP entry for %s\n", host);
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176 | return -1;
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177 | }
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178 | bb_perror_msg_and_die("SIOCDARP(priv)");
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179 | }
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180 | }
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181 | if ((flags & 1) && err) {
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182 | nopub:
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183 | req.arp_flags |= ATF_PUBL;
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184 | if (option_mask32 & ARP_OPT_v)
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185 | bb_error_msg("SIOCDARP(pub)");
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186 | if (ioctl(sockfd, SIOCDARP, &req) < 0) {
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187 | if (errno == ENXIO) {
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188 | printf("No ARP entry for %s\n", host);
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189 | return -1;
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190 | }
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191 | bb_perror_msg_and_die("SIOCDARP(pub)");
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192 | }
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193 | }
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194 | return 0;
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195 | }
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196 |
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197 | /* Get the hardware address to a specified interface name */
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198 | static void arp_getdevhw(char *ifname, struct sockaddr *sa,
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199 | const struct hwtype *hwt)
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200 | {
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201 | struct ifreq ifr;
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202 | const struct hwtype *xhw;
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203 |
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204 | strcpy(ifr.ifr_name, ifname);
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205 | ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr,
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206 | "cant get HW-Address for '%s'", ifname);
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207 | if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) {
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208 | bb_error_msg_and_die("protocol type mismatch");
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209 | }
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210 | memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr));
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211 |
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212 | if (option_mask32 & ARP_OPT_v) {
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213 | xhw = get_hwntype(ifr.ifr_hwaddr.sa_family);
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214 | if (!xhw || !xhw->print) {
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215 | xhw = get_hwntype(-1);
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216 | }
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217 | bb_error_msg("device '%s' has HW address %s '%s'",
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218 | ifname, xhw->name,
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219 | xhw->print((unsigned char *) &ifr.ifr_hwaddr.sa_data));
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220 | }
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221 | }
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222 |
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223 | /* Set an entry in the ARP cache. */
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224 | /* Called only from main, once */
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225 | static int arp_set(char **args)
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226 | {
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227 | char *host;
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228 | struct arpreq req;
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229 | struct sockaddr sa;
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230 | int flags;
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231 |
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232 | memset(&req, 0, sizeof(req));
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233 |
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234 | host = *args++;
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235 | if (ap->input(host, &sa) < 0) {
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236 | bb_herror_msg_and_die("%s", host);
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237 | }
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238 | /* If a host has more than one address, use the correct one! */
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239 | memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr));
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240 |
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241 | /* Fetch the hardware address. */
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242 | if (*args == NULL) {
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243 | bb_error_msg_and_die("need hardware address");
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244 | }
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245 | if (option_mask32 & ARP_OPT_D) {
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246 | arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL);
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247 | } else {
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248 | if (hw->input(*args++, &req.arp_ha) < 0) {
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249 | bb_error_msg_and_die("invalid hardware address");
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250 | }
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251 | }
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252 |
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253 | /* Check out any modifiers. */
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254 | flags = ATF_PERM | ATF_COM;
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255 | while (*args != NULL) {
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256 | switch (index_in_strings(options, *args)) {
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257 | case 0: /* "pub" */
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258 | flags |= ATF_PUBL;
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259 | args++;
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260 | break;
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261 | case 1: /* "priv" */
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262 | flags &= ~ATF_PUBL;
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263 | args++;
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264 | break;
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265 | case 2: /* "temp" */
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266 | flags &= ~ATF_PERM;
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267 | args++;
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268 | break;
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269 | case 3: /* "trail" */
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270 | flags |= ATF_USETRAILERS;
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271 | args++;
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272 | break;
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273 | case 4: /* "dontpub" */
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274 | #ifdef HAVE_ATF_DONTPUB
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275 | flags |= ATF_DONTPUB;
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276 | #else
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277 | bb_error_msg("feature ATF_DONTPUB is not supported");
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278 | #endif
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279 | args++;
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280 | break;
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281 | case 5: /* "auto" */
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282 | #ifdef HAVE_ATF_MAGIC
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283 | flags |= ATF_MAGIC;
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284 | #else
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285 | bb_error_msg("feature ATF_MAGIC is not supported");
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286 | #endif
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287 | args++;
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288 | break;
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289 | case 6: /* "dev" */
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290 | if (*++args == NULL)
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291 | bb_show_usage();
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292 | device = *args;
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293 | args++;
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294 | break;
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295 | case 7: /* "netmask" */
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296 | if (*++args == NULL)
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297 | bb_show_usage();
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298 | if (strcmp(*args, "255.255.255.255") != 0) {
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299 | host = *args;
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300 | if (ap->input(host, &sa) < 0) {
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301 | bb_herror_msg_and_die("%s", host);
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302 | }
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303 | memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr));
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304 | flags |= ATF_NETMASK;
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305 | }
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306 | args++;
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307 | break;
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308 | default:
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309 | bb_show_usage();
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310 | break;
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311 | }
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312 | }
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313 |
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314 | /* Fill in the remainder of the request. */
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315 | req.arp_flags = flags;
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316 |
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317 | strncpy(req.arp_dev, device, sizeof(req.arp_dev));
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318 |
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319 | /* Call the kernel. */
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320 | if (option_mask32 & ARP_OPT_v)
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321 | bb_error_msg("SIOCSARP()");
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322 | xioctl(sockfd, SIOCSARP, &req);
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323 | return 0;
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324 | }
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325 |
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326 |
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327 | /* Print the contents of an ARP request block. */
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328 | static void
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329 | arp_disp(const char *name, char *ip, int type, int arp_flags,
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330 | char *hwa, char *mask, char *dev)
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331 | {
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332 | static const int arp_masks[] = {
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333 | ATF_PERM, ATF_PUBL,
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334 | #ifdef HAVE_ATF_MAGIC
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335 | ATF_MAGIC,
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336 | #endif
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337 | #ifdef HAVE_ATF_DONTPUB
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338 | ATF_DONTPUB,
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339 | #endif
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340 | ATF_USETRAILERS,
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341 | };
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342 | static const char arp_labels[] ALIGN1 = "PERM\0""PUP\0"
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343 | #ifdef HAVE_ATF_MAGIC
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344 | "AUTO\0"
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345 | #endif
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346 | #ifdef HAVE_ATF_DONTPUB
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347 | "DONTPUB\0"
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348 | #endif
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349 | "TRAIL\0"
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350 | ;
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351 |
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352 | const struct hwtype *xhw;
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353 |
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354 | xhw = get_hwntype(type);
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355 | if (xhw == NULL)
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356 | xhw = get_hwtype(DFLT_HW);
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357 |
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358 | printf("%s (%s) at ", name, ip);
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359 |
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360 | if (!(arp_flags & ATF_COM)) {
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361 | if (arp_flags & ATF_PUBL)
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362 | printf("* ");
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363 | else
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364 | printf("<incomplete> ");
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365 | } else {
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366 | printf("%s [%s] ", hwa, xhw->name);
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367 | }
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368 |
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369 | if (arp_flags & ATF_NETMASK)
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370 | printf("netmask %s ", mask);
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371 |
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372 | print_flags_separated(arp_masks, arp_labels, arp_flags, " ");
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373 | printf(" on %s\n", dev);
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374 | }
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375 |
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376 | /* Display the contents of the ARP cache in the kernel. */
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377 | /* Called only from main, once */
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378 | static int arp_show(char *name)
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379 | {
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380 | const char *host;
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381 | const char *hostname;
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382 | FILE *fp;
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383 | struct sockaddr sa;
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384 | int type, flags;
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385 | int num;
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386 | unsigned entries = 0, shown = 0;
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387 | char ip[128];
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388 | char hwa[128];
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389 | char mask[128];
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390 | char line[128];
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391 | char dev[128];
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392 |
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393 | host = NULL;
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394 | if (name != NULL) {
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395 | /* Resolve the host name. */
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396 | if (ap->input(name, &sa) < 0) {
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397 | bb_herror_msg_and_die("%s", name);
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398 | }
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399 | host = xstrdup(ap->sprint(&sa, 1));
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400 | }
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401 | fp = xfopen_for_read("/proc/net/arp");
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402 | /* Bypass header -- read one line */
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403 | fgets(line, sizeof(line), fp);
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404 |
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405 | /* Read the ARP cache entries. */
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406 | while (fgets(line, sizeof(line), fp)) {
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407 |
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408 | mask[0] = '-'; mask[1] = '\0';
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409 | dev[0] = '-'; dev[1] = '\0';
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410 | /* All these strings can't overflow
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411 | * because fgets above reads limited amount of data */
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412 | num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n",
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413 | ip, &type, &flags, hwa, mask, dev);
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414 | if (num < 4)
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415 | break;
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416 |
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417 | entries++;
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418 | /* if the user specified hw-type differs, skip it */
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419 | if (hw_set && (type != hw->type))
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420 | continue;
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421 |
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422 | /* if the user specified address differs, skip it */
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423 | if (host && strcmp(ip, host) != 0)
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424 | continue;
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425 |
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426 | /* if the user specified device differs, skip it */
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427 | if (device[0] && strcmp(dev, device) != 0)
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428 | continue;
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429 |
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430 | shown++;
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431 | /* This IS ugly but it works -be */
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432 | hostname = "?";
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433 | if (!(option_mask32 & ARP_OPT_n)) {
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434 | if (ap->input(ip, &sa) < 0)
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435 | hostname = ip;
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436 | else
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437 | hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000);
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438 | if (strcmp(hostname, ip) == 0)
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439 | hostname = "?";
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440 | }
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441 |
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442 | arp_disp(hostname, ip, type, flags, hwa, mask, dev);
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443 | }
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444 | if (option_mask32 & ARP_OPT_v)
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445 | printf("Entries: %d\tSkipped: %d\tFound: %d\n",
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446 | entries, entries - shown, shown);
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447 |
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448 | if (!shown) {
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449 | if (hw_set || host || device[0])
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450 | printf("No match found in %d entries\n", entries);
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451 | }
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452 | if (ENABLE_FEATURE_CLEAN_UP) {
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453 | free((char*)host);
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454 | fclose(fp);
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455 | }
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456 | return 0;
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457 | }
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458 |
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459 | int arp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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460 | int arp_main(int argc UNUSED_PARAM, char **argv)
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461 | {
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462 | const char *hw_type = "ether";
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463 | const char *protocol;
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464 | unsigned opts;
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465 |
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466 | INIT_G();
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467 |
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468 | xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), sockfd);
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469 | ap = get_aftype(DFLT_AF);
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470 | if (!ap)
|
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471 | bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family");
|
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472 |
|
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473 | opts = getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol,
|
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474 | &hw_type, &hw_type, &device);
|
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475 | argv += optind;
|
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476 | if (opts & (ARP_OPT_A | ARP_OPT_p)) {
|
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477 | ap = get_aftype(protocol);
|
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478 | if (ap == NULL)
|
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479 | bb_error_msg_and_die("%s: unknown %s", protocol, "address family");
|
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480 | }
|
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481 | if (opts & (ARP_OPT_A | ARP_OPT_p)) {
|
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482 | hw = get_hwtype(hw_type);
|
---|
483 | if (hw == NULL)
|
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484 | bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type");
|
---|
485 | hw_set = 1;
|
---|
486 | }
|
---|
487 | //if (opts & ARP_OPT_i)... -i
|
---|
488 |
|
---|
489 | if (ap->af != AF_INET) {
|
---|
490 | bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name);
|
---|
491 | }
|
---|
492 |
|
---|
493 | /* If no hw type specified get default */
|
---|
494 | if (!hw) {
|
---|
495 | hw = get_hwtype(DFLT_HW);
|
---|
496 | if (!hw)
|
---|
497 | bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type");
|
---|
498 | }
|
---|
499 |
|
---|
500 | if (hw->alen <= 0) {
|
---|
501 | bb_error_msg_and_die("%s: %s without ARP support",
|
---|
502 | hw->name, "hardware type");
|
---|
503 | }
|
---|
504 |
|
---|
505 | /* Now see what we have to do here... */
|
---|
506 | if (opts & (ARP_OPT_d | ARP_OPT_s)) {
|
---|
507 | if (argv[0] == NULL)
|
---|
508 | bb_error_msg_and_die("need host name");
|
---|
509 | if (opts & ARP_OPT_s)
|
---|
510 | return arp_set(argv);
|
---|
511 | return arp_del(argv);
|
---|
512 | }
|
---|
513 | //if (opts & ARP_OPT_a) - default
|
---|
514 | return arp_show(argv[0]);
|
---|
515 | }
|
---|