| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Mini ipcalc implementation for busybox
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| 4 | *
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| 5 | * By Jordan Crouse <jordan@cosmicpenguin.net>
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| 6 | * Stephan Linz <linz@li-pro.net>
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| 7 | *
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| 8 | * This is a complete reimplementation of the ipcalc program
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| 9 | * from Red Hat. I didn't look at their source code, but there
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| 10 | * is no denying that this is a loving reimplementation
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| 11 | *
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| 12 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 13 | */
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| 14 |
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| 15 | //usage:#define ipcalc_trivial_usage
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| 16 | //usage: "[OPTIONS] ADDRESS"
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| 17 | //usage: IF_FEATURE_IPCALC_FANCY("[/PREFIX]") " [NETMASK]"
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| 18 | //usage:#define ipcalc_full_usage "\n\n"
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| 19 | //usage: "Calculate IP network settings from a IP address\n"
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| 20 | //usage: IF_FEATURE_IPCALC_LONG_OPTIONS(
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| 21 | //usage: "\n -b,--broadcast Display calculated broadcast address"
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| 22 | //usage: "\n -n,--network Display calculated network address"
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| 23 | //usage: "\n -m,--netmask Display default netmask for IP"
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| 24 | //usage: IF_FEATURE_IPCALC_FANCY(
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| 25 | //usage: "\n -p,--prefix Display the prefix for IP/NETMASK"
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| 26 | //usage: "\n -h,--hostname Display first resolved host name"
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| 27 | //usage: "\n -s,--silent Don't ever display error messages"
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| 28 | //usage: )
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| 29 | //usage: )
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| 30 | //usage: IF_NOT_FEATURE_IPCALC_LONG_OPTIONS(
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| 31 | //usage: "\n -b Display calculated broadcast address"
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| 32 | //usage: "\n -n Display calculated network address"
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| 33 | //usage: "\n -m Display default netmask for IP"
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| 34 | //usage: IF_FEATURE_IPCALC_FANCY(
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| 35 | //usage: "\n -p Display the prefix for IP/NETMASK"
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| 36 | //usage: "\n -h Display first resolved host name"
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| 37 | //usage: "\n -s Don't ever display error messages"
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| 38 | //usage: )
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| 39 | //usage: )
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| 40 |
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| 41 | #include "libbb.h"
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| 42 | /* After libbb.h, because on some systems it needs other includes */
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| 43 | #include <arpa/inet.h>
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| 44 |
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| 45 | #define CLASS_A_NETMASK ntohl(0xFF000000)
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| 46 | #define CLASS_B_NETMASK ntohl(0xFFFF0000)
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| 47 | #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
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| 48 |
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| 49 | static unsigned long get_netmask(unsigned long ipaddr)
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| 50 | {
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| 51 | ipaddr = htonl(ipaddr);
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| 52 |
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| 53 | if ((ipaddr & 0xC0000000) == 0xC0000000)
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| 54 | return CLASS_C_NETMASK;
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| 55 | else if ((ipaddr & 0x80000000) == 0x80000000)
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| 56 | return CLASS_B_NETMASK;
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| 57 | else if ((ipaddr & 0x80000000) == 0)
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| 58 | return CLASS_A_NETMASK;
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| 59 | else
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| 60 | return 0;
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| 61 | }
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| 62 |
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| 63 | #if ENABLE_FEATURE_IPCALC_FANCY
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| 64 | static int get_prefix(unsigned long netmask)
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| 65 | {
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| 66 | unsigned long msk = 0x80000000;
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| 67 | int ret = 0;
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| 68 |
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| 69 | netmask = htonl(netmask);
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| 70 | while (msk) {
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| 71 | if (netmask & msk)
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| 72 | ret++;
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| 73 | msk >>= 1;
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| 74 | }
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| 75 | return ret;
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| 76 | }
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| 77 | #else
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| 78 | int get_prefix(unsigned long netmask);
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| 79 | #endif
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| 80 |
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| 81 |
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| 82 | #define NETMASK 0x01
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| 83 | #define BROADCAST 0x02
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| 84 | #define NETWORK 0x04
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| 85 | #define NETPREFIX 0x08
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| 86 | #define HOSTNAME 0x10
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| 87 | #define SILENT 0x20
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| 88 |
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| 89 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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| 90 | static const char ipcalc_longopts[] ALIGN1 =
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| 91 | "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
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| 92 | "broadcast\0" No_argument "b" // broadcast from IP [netmask]
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| 93 | "network\0" No_argument "n" // network from IP [netmask]
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| 94 | # if ENABLE_FEATURE_IPCALC_FANCY
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| 95 | "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask]
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| 96 | "hostname\0" No_argument "h" // hostname from IP
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| 97 | "silent\0" No_argument "s" // don’t ever display error messages
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| 98 | # endif
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| 99 | ;
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| 100 | #endif
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| 101 |
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| 102 | int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 103 | int ipcalc_main(int argc UNUSED_PARAM, char **argv)
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| 104 | {
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| 105 | unsigned opt;
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| 106 | bool have_netmask = 0;
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| 107 | struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
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| 108 | /* struct in_addr { in_addr_t s_addr; } and in_addr_t
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| 109 | * (which in turn is just a typedef to uint32_t)
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| 110 | * are essentially the same type. A few macros for less verbosity: */
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| 111 | #define netmask (s_netmask.s_addr)
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| 112 | #define broadcast (s_broadcast.s_addr)
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| 113 | #define network (s_network.s_addr)
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| 114 | #define ipaddr (s_ipaddr.s_addr)
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| 115 | char *ipstr;
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| 116 |
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| 117 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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| 118 | applet_long_options = ipcalc_longopts;
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| 119 | #endif
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| 120 | opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */
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| 121 | opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
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| 122 | argv += optind;
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| 123 | if (opt & SILENT)
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| 124 | logmode = LOGMODE_NONE; /* suppress error_msg() output */
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| 125 | opt &= ~SILENT;
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| 126 | if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
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| 127 | /* if no options at all or
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| 128 | * (no broadcast,network,prefix) and (two args)... */
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| 129 | if (!opt || argv[1])
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| 130 | bb_show_usage();
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| 131 | }
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| 132 |
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| 133 | ipstr = argv[0];
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| 134 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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| 135 | unsigned long netprefix = 0;
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| 136 | char *prefixstr;
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| 137 |
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| 138 | prefixstr = ipstr;
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| 139 |
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| 140 | while (*prefixstr) {
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| 141 | if (*prefixstr == '/') {
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| 142 | *prefixstr++ = '\0';
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| 143 | if (*prefixstr) {
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| 144 | unsigned msk;
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| 145 | netprefix = xatoul_range(prefixstr, 0, 32);
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| 146 | netmask = 0;
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| 147 | msk = 0x80000000;
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| 148 | while (netprefix > 0) {
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| 149 | netmask |= msk;
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| 150 | msk >>= 1;
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| 151 | netprefix--;
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| 152 | }
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| 153 | netmask = htonl(netmask);
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| 154 | /* Even if it was 0, we will signify that we have a netmask. This allows */
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| 155 | /* for specification of default routes, etc which have a 0 netmask/prefix */
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| 156 | have_netmask = 1;
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| 157 | }
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| 158 | break;
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| 159 | }
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| 160 | prefixstr++;
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| 161 | }
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| 162 | }
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| 163 |
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| 164 | if (inet_aton(ipstr, &s_ipaddr) == 0) {
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| 165 | bb_error_msg_and_die("bad IP address: %s", argv[0]);
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| 166 | }
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| 167 |
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| 168 | if (argv[1]) {
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| 169 | if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
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| 170 | bb_error_msg_and_die("use prefix or netmask, not both");
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| 171 | }
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| 172 | if (inet_aton(argv[1], &s_netmask) == 0) {
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| 173 | bb_error_msg_and_die("bad netmask: %s", argv[1]);
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| 174 | }
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| 175 | } else {
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| 176 | /* JHC - If the netmask wasn't provided then calculate it */
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| 177 | if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
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| 178 | netmask = get_netmask(ipaddr);
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| 179 | }
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| 180 |
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| 181 | if (opt & NETMASK) {
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| 182 | printf("NETMASK=%s\n", inet_ntoa(s_netmask));
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| 183 | }
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| 184 |
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| 185 | if (opt & BROADCAST) {
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| 186 | broadcast = (ipaddr & netmask) | ~netmask;
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| 187 | printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
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| 188 | }
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| 189 |
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| 190 | if (opt & NETWORK) {
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| 191 | network = ipaddr & netmask;
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| 192 | printf("NETWORK=%s\n", inet_ntoa(s_network));
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| 193 | }
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| 194 |
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| 195 | if (ENABLE_FEATURE_IPCALC_FANCY) {
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| 196 | if (opt & NETPREFIX) {
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| 197 | printf("PREFIX=%i\n", get_prefix(netmask));
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| 198 | }
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| 199 |
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| 200 | if (opt & HOSTNAME) {
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| 201 | struct hostent *hostinfo;
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| 202 |
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| 203 | hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
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| 204 | if (!hostinfo) {
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| 205 | bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
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| 206 | }
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| 207 | str_tolower(hostinfo->h_name);
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| 208 |
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| 209 | printf("HOSTNAME=%s\n", hostinfo->h_name);
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| 210 | }
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| 211 | }
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| 212 |
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| 213 | return EXIT_SUCCESS;
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| 214 | }
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