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 | #define ARP_OPT_A (0x1) |
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31 | #define ARP_OPT_p (0x2) |
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32 | #define ARP_OPT_H (0x4) |
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33 | #define ARP_OPT_t (0x8) |
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34 | #define ARP_OPT_i (0x10) |
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35 | #define ARP_OPT_a (0x20) |
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36 | #define ARP_OPT_d (0x40) |
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37 | #define ARP_OPT_n (0x80) /* do not resolve addresses */ |
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38 | #define ARP_OPT_D (0x100) /* HW-address is devicename */ |
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39 | #define ARP_OPT_s (0x200) |
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40 | #define ARP_OPT_v (0x400 * DEBUG) /* debugging output flag */ |
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41 | |
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42 | |
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43 | static const struct aftype *ap; /* current address family */ |
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44 | static const struct hwtype *hw; /* current hardware type */ |
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45 | static int sockfd; /* active socket descriptor */ |
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46 | static smallint hw_set; /* flag if hw-type was set (-H) */ |
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47 | static const char *device = ""; /* current device */ |
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48 | |
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49 | static const char options[] ALIGN1 = |
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50 | "pub\0" |
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51 | "priv\0" |
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52 | "temp\0" |
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53 | "trail\0" |
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54 | "dontpub\0" |
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55 | "auto\0" |
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56 | "dev\0" |
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57 | "netmask\0"; |
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58 | |
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59 | /* Delete an entry from the ARP cache. */ |
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60 | /* Called only from main, once */ |
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61 | static int arp_del(char **args) |
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62 | { |
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63 | char *host; |
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64 | struct arpreq req; |
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65 | struct sockaddr sa; |
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66 | int flags = 0; |
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67 | int err; |
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68 | |
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69 | memset(&req, 0, sizeof(req)); |
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70 | |
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71 | /* Resolve the host name. */ |
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72 | host = *args; |
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73 | if (ap->input(host, &sa) < 0) { |
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74 | bb_herror_msg_and_die("%s", host); |
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75 | } |
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76 | |
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77 | /* If a host has more than one address, use the correct one! */ |
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78 | memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); |
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79 | |
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80 | if (hw_set) |
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81 | req.arp_ha.sa_family = hw->type; |
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82 | |
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83 | req.arp_flags = ATF_PERM; |
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84 | args++; |
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85 | while (*args != NULL) { |
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86 | switch (index_in_strings(options, *args)) { |
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87 | case 0: /* "pub" */ |
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88 | flags |= 1; |
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89 | args++; |
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90 | break; |
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91 | case 1: /* "priv" */ |
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92 | flags |= 2; |
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93 | args++; |
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94 | break; |
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95 | case 2: /* "temp" */ |
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96 | req.arp_flags &= ~ATF_PERM; |
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97 | args++; |
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98 | break; |
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99 | case 3: /* "trail" */ |
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100 | req.arp_flags |= ATF_USETRAILERS; |
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101 | args++; |
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102 | break; |
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103 | case 4: /* "dontpub" */ |
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104 | #ifdef HAVE_ATF_DONTPUB |
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105 | req.arp_flags |= ATF_DONTPUB; |
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106 | #else |
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107 | bb_error_msg("feature ATF_DONTPUB is not supported"); |
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108 | #endif |
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109 | args++; |
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110 | break; |
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111 | case 5: /* "auto" */ |
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112 | #ifdef HAVE_ATF_MAGIC |
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113 | req.arp_flags |= ATF_MAGIC; |
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114 | #else |
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115 | bb_error_msg("feature ATF_MAGIC is not supported"); |
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116 | #endif |
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117 | args++; |
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118 | break; |
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119 | case 6: /* "dev" */ |
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120 | if (*++args == NULL) |
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121 | bb_show_usage(); |
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122 | device = *args; |
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123 | args++; |
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124 | break; |
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125 | case 7: /* "netmask" */ |
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126 | if (*++args == NULL) |
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127 | bb_show_usage(); |
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128 | if (strcmp(*args, "255.255.255.255") != 0) { |
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129 | host = *args; |
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130 | if (ap->input(host, &sa) < 0) { |
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131 | bb_herror_msg_and_die("%s", host); |
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132 | } |
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133 | memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); |
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134 | req.arp_flags |= ATF_NETMASK; |
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135 | } |
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136 | args++; |
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137 | break; |
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138 | default: |
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139 | bb_show_usage(); |
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140 | break; |
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141 | } |
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142 | } |
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143 | if (flags == 0) |
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144 | flags = 3; |
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145 | |
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146 | strncpy(req.arp_dev, device, sizeof(req.arp_dev)); |
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147 | |
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148 | err = -1; |
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149 | |
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150 | /* Call the kernel. */ |
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151 | if (flags & 2) { |
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152 | if (option_mask32 & ARP_OPT_v) |
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153 | bb_error_msg("SIOCDARP(nopub)"); |
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154 | err = ioctl(sockfd, SIOCDARP, &req); |
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155 | if (err < 0) { |
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156 | if (errno == ENXIO) { |
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157 | if (flags & 1) |
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158 | goto nopub; |
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159 | printf("No ARP entry for %s\n", host); |
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160 | return -1; |
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161 | } |
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162 | bb_perror_msg_and_die("SIOCDARP(priv)"); |
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163 | } |
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164 | } |
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165 | if ((flags & 1) && err) { |
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166 | nopub: |
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167 | req.arp_flags |= ATF_PUBL; |
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168 | if (option_mask32 & ARP_OPT_v) |
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169 | bb_error_msg("SIOCDARP(pub)"); |
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170 | if (ioctl(sockfd, SIOCDARP, &req) < 0) { |
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171 | if (errno == ENXIO) { |
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172 | printf("No ARP entry for %s\n", host); |
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173 | return -1; |
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174 | } |
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175 | bb_perror_msg_and_die("SIOCDARP(pub)"); |
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176 | } |
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177 | } |
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178 | return 0; |
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179 | } |
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180 | |
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181 | /* Get the hardware address to a specified interface name */ |
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182 | static void arp_getdevhw(char *ifname, struct sockaddr *sa, |
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183 | const struct hwtype *hwt) |
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184 | { |
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185 | struct ifreq ifr; |
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186 | const struct hwtype *xhw; |
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187 | |
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188 | strcpy(ifr.ifr_name, ifname); |
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189 | ioctl_or_perror_and_die(sockfd, SIOCGIFHWADDR, &ifr, |
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190 | "cant get HW-Address for '%s'", ifname); |
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191 | if (hwt && (ifr.ifr_hwaddr.sa_family != hw->type)) { |
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192 | bb_error_msg_and_die("protocol type mismatch"); |
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193 | } |
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194 | memcpy(sa, &(ifr.ifr_hwaddr), sizeof(struct sockaddr)); |
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195 | |
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196 | if (option_mask32 & ARP_OPT_v) { |
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197 | xhw = get_hwntype(ifr.ifr_hwaddr.sa_family); |
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198 | if (!xhw || !xhw->print) { |
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199 | xhw = get_hwntype(-1); |
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200 | } |
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201 | bb_error_msg("device '%s' has HW address %s '%s'", |
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202 | ifname, xhw->name, |
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203 | xhw->print((char *) &ifr.ifr_hwaddr.sa_data)); |
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204 | } |
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205 | } |
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206 | |
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207 | /* Set an entry in the ARP cache. */ |
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208 | /* Called only from main, once */ |
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209 | static int arp_set(char **args) |
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210 | { |
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211 | char *host; |
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212 | struct arpreq req; |
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213 | struct sockaddr sa; |
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214 | int flags; |
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215 | |
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216 | memset(&req, 0, sizeof(req)); |
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217 | |
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218 | host = *args++; |
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219 | if (ap->input(host, &sa) < 0) { |
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220 | bb_herror_msg_and_die("%s", host); |
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221 | } |
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222 | /* If a host has more than one address, use the correct one! */ |
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223 | memcpy(&req.arp_pa, &sa, sizeof(struct sockaddr)); |
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224 | |
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225 | /* Fetch the hardware address. */ |
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226 | if (*args == NULL) { |
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227 | bb_error_msg_and_die("need hardware address"); |
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228 | } |
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229 | if (option_mask32 & ARP_OPT_D) { |
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230 | arp_getdevhw(*args++, &req.arp_ha, hw_set ? hw : NULL); |
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231 | } else { |
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232 | if (hw->input(*args++, &req.arp_ha) < 0) { |
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233 | bb_error_msg_and_die("invalid hardware address"); |
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234 | } |
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235 | } |
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236 | |
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237 | /* Check out any modifiers. */ |
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238 | flags = ATF_PERM | ATF_COM; |
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239 | while (*args != NULL) { |
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240 | switch (index_in_strings(options, *args)) { |
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241 | case 0: /* "pub" */ |
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242 | flags |= ATF_PUBL; |
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243 | args++; |
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244 | break; |
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245 | case 1: /* "priv" */ |
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246 | flags &= ~ATF_PUBL; |
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247 | args++; |
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248 | break; |
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249 | case 2: /* "temp" */ |
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250 | flags &= ~ATF_PERM; |
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251 | args++; |
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252 | break; |
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253 | case 3: /* "trail" */ |
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254 | flags |= ATF_USETRAILERS; |
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255 | args++; |
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256 | break; |
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257 | case 4: /* "dontpub" */ |
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258 | #ifdef HAVE_ATF_DONTPUB |
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259 | flags |= ATF_DONTPUB; |
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260 | #else |
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261 | bb_error_msg("feature ATF_DONTPUB is not supported"); |
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262 | #endif |
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263 | args++; |
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264 | break; |
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265 | case 5: /* "auto" */ |
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266 | #ifdef HAVE_ATF_MAGIC |
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267 | flags |= ATF_MAGIC; |
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268 | #else |
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269 | bb_error_msg("feature ATF_MAGIC is not supported"); |
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270 | #endif |
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271 | args++; |
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272 | break; |
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273 | case 6: /* "dev" */ |
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274 | if (*++args == NULL) |
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275 | bb_show_usage(); |
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276 | device = *args; |
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277 | args++; |
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278 | break; |
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279 | case 7: /* "netmask" */ |
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280 | if (*++args == NULL) |
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281 | bb_show_usage(); |
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282 | if (strcmp(*args, "255.255.255.255") != 0) { |
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283 | host = *args; |
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284 | if (ap->input(host, &sa) < 0) { |
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285 | bb_herror_msg_and_die("%s", host); |
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286 | } |
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287 | memcpy(&req.arp_netmask, &sa, sizeof(struct sockaddr)); |
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288 | flags |= ATF_NETMASK; |
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289 | } |
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290 | args++; |
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291 | break; |
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292 | default: |
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293 | bb_show_usage(); |
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294 | break; |
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295 | } |
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296 | } |
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297 | |
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298 | /* Fill in the remainder of the request. */ |
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299 | req.arp_flags = flags; |
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300 | |
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301 | strncpy(req.arp_dev, device, sizeof(req.arp_dev)); |
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302 | |
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303 | /* Call the kernel. */ |
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304 | if (option_mask32 & ARP_OPT_v) |
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305 | bb_error_msg("SIOCSARP()"); |
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306 | xioctl(sockfd, SIOCSARP, &req); |
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307 | return 0; |
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308 | } |
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309 | |
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310 | |
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311 | /* Print the contents of an ARP request block. */ |
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312 | static void |
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313 | arp_disp(const char *name, char *ip, int type, int arp_flags, |
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314 | char *hwa, char *mask, char *dev) |
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315 | { |
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316 | const struct hwtype *xhw; |
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317 | |
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318 | xhw = get_hwntype(type); |
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319 | if (xhw == NULL) |
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320 | xhw = get_hwtype(DFLT_HW); |
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321 | |
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322 | printf("%s (%s) at ", name, ip); |
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323 | |
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324 | if (!(arp_flags & ATF_COM)) { |
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325 | if (arp_flags & ATF_PUBL) |
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326 | printf("* "); |
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327 | else |
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328 | printf("<incomplete> "); |
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329 | } else { |
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330 | printf("%s [%s] ", hwa, xhw->name); |
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331 | } |
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332 | |
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333 | if (arp_flags & ATF_NETMASK) |
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334 | printf("netmask %s ", mask); |
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335 | |
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336 | if (arp_flags & ATF_PERM) |
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337 | printf("PERM "); |
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338 | if (arp_flags & ATF_PUBL) |
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339 | printf("PUP "); |
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340 | #ifdef HAVE_ATF_MAGIC |
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341 | if (arp_flags & ATF_MAGIC) |
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342 | printf("AUTO "); |
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343 | #endif |
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344 | #ifdef HAVE_ATF_DONTPUB |
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345 | if (arp_flags & ATF_DONTPUB) |
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346 | printf("DONTPUB "); |
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347 | #endif |
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348 | if (arp_flags & ATF_USETRAILERS) |
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349 | printf("TRAIL "); |
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350 | |
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351 | printf("on %s\n", dev); |
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352 | } |
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353 | |
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354 | /* Display the contents of the ARP cache in the kernel. */ |
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355 | /* Called only from main, once */ |
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356 | static int arp_show(char *name) |
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357 | { |
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358 | const char *host; |
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359 | const char *hostname; |
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360 | FILE *fp; |
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361 | struct sockaddr sa; |
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362 | int type, flags; |
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363 | int num; |
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364 | unsigned entries = 0, shown = 0; |
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365 | char ip[128]; |
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366 | char hwa[128]; |
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367 | char mask[128]; |
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368 | char line[128]; |
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369 | char dev[128]; |
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370 | |
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371 | host = NULL; |
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372 | if (name != NULL) { |
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373 | /* Resolve the host name. */ |
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374 | if (ap->input(name, &sa) < 0) { |
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375 | bb_herror_msg_and_die("%s", name); |
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376 | } |
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377 | host = xstrdup(ap->sprint(&sa, 1)); |
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378 | } |
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379 | fp = xfopen("/proc/net/arp", "r"); |
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380 | /* Bypass header -- read one line */ |
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381 | fgets(line, sizeof(line), fp); |
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382 | |
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383 | /* Read the ARP cache entries. */ |
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384 | while (fgets(line, sizeof(line), fp)) { |
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385 | |
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386 | mask[0] = '-'; mask[1] = '\0'; |
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387 | dev[0] = '-'; dev[1] = '\0'; |
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388 | /* All these strings can't overflow |
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389 | * because fgets above reads limited amount of data */ |
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390 | num = sscanf(line, "%s 0x%x 0x%x %s %s %s\n", |
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391 | ip, &type, &flags, hwa, mask, dev); |
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392 | if (num < 4) |
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393 | break; |
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394 | |
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395 | entries++; |
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396 | /* if the user specified hw-type differs, skip it */ |
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397 | if (hw_set && (type != hw->type)) |
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398 | continue; |
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399 | |
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400 | /* if the user specified address differs, skip it */ |
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401 | if (host && strcmp(ip, host) != 0) |
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402 | continue; |
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403 | |
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404 | /* if the user specified device differs, skip it */ |
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405 | if (device[0] && strcmp(dev, device) != 0) |
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406 | continue; |
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407 | |
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408 | shown++; |
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409 | /* This IS ugly but it works -be */ |
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410 | hostname = "?"; |
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411 | if (!(option_mask32 & ARP_OPT_n)) { |
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412 | if (ap->input(ip, &sa) < 0) |
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413 | hostname = ip; |
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414 | else |
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415 | hostname = ap->sprint(&sa, (option_mask32 & ARP_OPT_n) | 0x8000); |
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416 | if (strcmp(hostname, ip) == 0) |
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417 | hostname = "?"; |
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418 | } |
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419 | |
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420 | arp_disp(hostname, ip, type, flags, hwa, mask, dev); |
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421 | } |
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422 | if (option_mask32 & ARP_OPT_v) |
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423 | printf("Entries: %d\tSkipped: %d\tFound: %d\n", |
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424 | entries, entries - shown, shown); |
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425 | |
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426 | if (!shown) { |
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427 | if (hw_set || host || device[0]) |
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428 | printf("No match found in %d entries\n", entries); |
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429 | } |
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430 | if (ENABLE_FEATURE_CLEAN_UP) { |
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431 | free((char*)host); |
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432 | fclose(fp); |
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433 | } |
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434 | return 0; |
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435 | } |
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436 | |
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437 | int arp_main(int argc, char **argv); |
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438 | int arp_main(int argc, char **argv) |
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439 | { |
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440 | char *hw_type; |
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441 | char *protocol; |
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442 | |
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443 | /* Initialize variables... */ |
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444 | ap = get_aftype(DFLT_AF); |
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445 | if (!ap) |
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446 | bb_error_msg_and_die("%s: %s not supported", DFLT_AF, "address family"); |
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447 | |
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448 | getopt32(argv, "A:p:H:t:i:adnDsv", &protocol, &protocol, |
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449 | &hw_type, &hw_type, &device); |
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450 | argv += optind; |
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451 | if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { |
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452 | ap = get_aftype(protocol); |
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453 | if (ap == NULL) |
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454 | bb_error_msg_and_die("%s: unknown %s", protocol, "address family"); |
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455 | } |
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456 | if (option_mask32 & ARP_OPT_A || option_mask32 & ARP_OPT_p) { |
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457 | hw = get_hwtype(hw_type); |
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458 | if (hw == NULL) |
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459 | bb_error_msg_and_die("%s: unknown %s", hw_type, "hardware type"); |
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460 | hw_set = 1; |
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461 | } |
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462 | //if (option_mask32 & ARP_OPT_i)... -i |
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463 | |
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464 | if (ap->af != AF_INET) { |
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465 | bb_error_msg_and_die("%s: kernel only supports 'inet'", ap->name); |
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466 | } |
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467 | |
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468 | /* If no hw type specified get default */ |
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469 | if (!hw) { |
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470 | hw = get_hwtype(DFLT_HW); |
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471 | if (!hw) |
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472 | bb_error_msg_and_die("%s: %s not supported", DFLT_HW, "hardware type"); |
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473 | } |
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474 | |
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475 | if (hw->alen <= 0) { |
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476 | bb_error_msg_and_die("%s: %s without ARP support", |
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477 | hw->name, "hardware type"); |
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478 | } |
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479 | sockfd = xsocket(AF_INET, SOCK_DGRAM, 0); |
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480 | |
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481 | /* Now see what we have to do here... */ |
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482 | if (option_mask32 & (ARP_OPT_d|ARP_OPT_s)) { |
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483 | if (argv[0] == NULL) |
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484 | bb_error_msg_and_die("need host name"); |
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485 | if (option_mask32 & ARP_OPT_s) |
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486 | return arp_set(argv); |
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487 | return arp_del(argv); |
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488 | } |
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489 | //if (option_mask32 & ARP_OPT_a) - default |
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490 | return arp_show(argv[0]); |
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491 | } |
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