238 lines
6.7 KiB
C
238 lines
6.7 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini ipcalc implementation for busybox
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*
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* By Jordan Crouse <jordan@cosmicpenguin.net>
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* Stephan Linz <linz@li-pro.net>
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*
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* This is a complete reimplementation of the ipcalc program
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* from Red Hat. I didn't look at their source code, but there
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* is no denying that this is a loving reimplementation
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config IPCALC
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//config: bool "ipcalc (4.3 kb)"
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//config: default y
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//config: help
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//config: ipcalc takes an IP address and netmask and calculates the
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//config: resulting broadcast, network, and host range.
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//config:
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//config:config FEATURE_IPCALC_LONG_OPTIONS
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//config: bool "Enable long options"
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//config: default y
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//config: depends on IPCALC && LONG_OPTS
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//config:
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//config:config FEATURE_IPCALC_FANCY
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//config: bool "Fancy IPCALC, more options, adds 1 kbyte"
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//config: default y
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//config: depends on IPCALC
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//config: help
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//config: Adds the options hostname, prefix and silent to the output of
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//config: "ipcalc".
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//applet:IF_IPCALC(APPLET(ipcalc, BB_DIR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_IPCALC) += ipcalc.o
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//usage:#define ipcalc_trivial_usage
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//usage: "[OPTIONS] ADDRESS"
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//usage: IF_FEATURE_IPCALC_FANCY("[/PREFIX]") " [NETMASK]"
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//usage:#define ipcalc_full_usage "\n\n"
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//usage: "Calculate IP network settings from a IP address\n"
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//usage: IF_FEATURE_IPCALC_LONG_OPTIONS(
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//usage: "\n -b,--broadcast Display calculated broadcast address"
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//usage: "\n -n,--network Display calculated network address"
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//usage: "\n -m,--netmask Display default netmask for IP"
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//usage: IF_FEATURE_IPCALC_FANCY(
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//usage: "\n -p,--prefix Display the prefix for IP/NETMASK"
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//usage: "\n -h,--hostname Display first resolved host name"
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//usage: "\n -s,--silent Don't ever display error messages"
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//usage: )
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//usage: )
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//usage: IF_NOT_FEATURE_IPCALC_LONG_OPTIONS(
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//usage: "\n -b Display calculated broadcast address"
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//usage: "\n -n Display calculated network address"
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//usage: "\n -m Display default netmask for IP"
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//usage: IF_FEATURE_IPCALC_FANCY(
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//usage: "\n -p Display the prefix for IP/NETMASK"
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//usage: "\n -h Display first resolved host name"
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//usage: "\n -s Don't ever display error messages"
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//usage: )
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//usage: )
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#include "libbb.h"
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/* After libbb.h, because on some systems it needs other includes */
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#include <arpa/inet.h>
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#define CLASS_A_NETMASK ntohl(0xFF000000)
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#define CLASS_B_NETMASK ntohl(0xFFFF0000)
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#define CLASS_C_NETMASK ntohl(0xFFFFFF00)
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static unsigned long get_netmask(unsigned long ipaddr)
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{
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ipaddr = htonl(ipaddr);
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if ((ipaddr & 0xC0000000) == 0xC0000000)
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return CLASS_C_NETMASK;
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else if ((ipaddr & 0x80000000) == 0x80000000)
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return CLASS_B_NETMASK;
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else if ((ipaddr & 0x80000000) == 0)
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return CLASS_A_NETMASK;
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else
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return 0;
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}
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#if ENABLE_FEATURE_IPCALC_FANCY
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static int get_prefix(unsigned long netmask)
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{
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unsigned long msk = 0x80000000;
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int ret = 0;
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netmask = htonl(netmask);
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while (msk) {
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if (netmask & msk)
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ret++;
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msk >>= 1;
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}
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return ret;
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}
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#else
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int get_prefix(unsigned long netmask);
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#endif
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#define NETMASK 0x01
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#define BROADCAST 0x02
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#define NETWORK 0x04
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#define NETPREFIX 0x08
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#define HOSTNAME 0x10
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#define SILENT 0x20
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#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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static const char ipcalc_longopts[] ALIGN1 =
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"netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
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"broadcast\0" No_argument "b" // broadcast from IP [netmask]
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"network\0" No_argument "n" // network from IP [netmask]
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# if ENABLE_FEATURE_IPCALC_FANCY
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"prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask]
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"hostname\0" No_argument "h" // hostname from IP
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"silent\0" No_argument "s" // don’t ever display error messages
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# endif
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;
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#endif
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int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int ipcalc_main(int argc UNUSED_PARAM, char **argv)
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{
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unsigned opt;
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bool have_netmask = 0;
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struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
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/* struct in_addr { in_addr_t s_addr; } and in_addr_t
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* (which in turn is just a typedef to uint32_t)
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* are essentially the same type. A few macros for less verbosity: */
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#define netmask (s_netmask.s_addr)
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#define broadcast (s_broadcast.s_addr)
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#define network (s_network.s_addr)
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#define ipaddr (s_ipaddr.s_addr)
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char *ipstr;
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#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
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applet_long_options = ipcalc_longopts;
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#endif
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opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */
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opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
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argv += optind;
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if (opt & SILENT)
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logmode = LOGMODE_NONE; /* suppress error_msg() output */
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opt &= ~SILENT;
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if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
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/* if no options at all or
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* (no broadcast,network,prefix) and (two args)... */
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if (!opt || argv[1])
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bb_show_usage();
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}
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ipstr = argv[0];
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if (ENABLE_FEATURE_IPCALC_FANCY) {
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unsigned long netprefix = 0;
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char *prefixstr;
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prefixstr = ipstr;
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while (*prefixstr) {
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if (*prefixstr == '/') {
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*prefixstr++ = '\0';
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if (*prefixstr) {
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unsigned msk;
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netprefix = xatoul_range(prefixstr, 0, 32);
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netmask = 0;
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msk = 0x80000000;
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while (netprefix > 0) {
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netmask |= msk;
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msk >>= 1;
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netprefix--;
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}
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netmask = htonl(netmask);
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/* Even if it was 0, we will signify that we have a netmask. This allows */
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/* for specification of default routes, etc which have a 0 netmask/prefix */
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have_netmask = 1;
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}
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break;
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}
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prefixstr++;
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}
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}
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if (inet_aton(ipstr, &s_ipaddr) == 0) {
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bb_error_msg_and_die("bad IP address: %s", argv[0]);
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}
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if (argv[1]) {
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if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
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bb_error_msg_and_die("use prefix or netmask, not both");
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}
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if (inet_aton(argv[1], &s_netmask) == 0) {
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bb_error_msg_and_die("bad netmask: %s", argv[1]);
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}
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} else {
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/* JHC - If the netmask wasn't provided then calculate it */
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if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
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netmask = get_netmask(ipaddr);
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}
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if (opt & NETMASK) {
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printf("NETMASK=%s\n", inet_ntoa(s_netmask));
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}
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if (opt & BROADCAST) {
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broadcast = (ipaddr & netmask) | ~netmask;
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printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
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}
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if (opt & NETWORK) {
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network = ipaddr & netmask;
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printf("NETWORK=%s\n", inet_ntoa(s_network));
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}
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if (ENABLE_FEATURE_IPCALC_FANCY) {
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if (opt & NETPREFIX) {
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printf("PREFIX=%i\n", get_prefix(netmask));
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}
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if (opt & HOSTNAME) {
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struct hostent *hostinfo;
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hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
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if (!hostinfo) {
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bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
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}
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str_tolower(hostinfo->h_name);
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printf("HOSTNAME=%s\n", hostinfo->h_name);
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}
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}
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return EXIT_SUCCESS;
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}
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