/* vi: set sw=4 ts=4: */ /* * Mini ipcalc implementation for busybox * * By Jordan Crouse * Stephan Linz * * This is a complete reimplementation of the ipcalc program * from Red Hat. I didn't look at their source code, but there * is no denying that this is a loving reimplementation * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ //config:config IPCALC //config: bool "ipcalc (4.4 kb)" //config: default y //config: help //config: ipcalc takes an IP address and netmask and calculates the //config: resulting broadcast, network, and host range. //config: //config:config FEATURE_IPCALC_LONG_OPTIONS //config: bool "Enable long options" //config: default y //config: depends on IPCALC && LONG_OPTS //config: //config:config FEATURE_IPCALC_FANCY //config: bool "Fancy IPCALC, more options, adds 1 kbyte" //config: default y //config: depends on IPCALC //config: help //config: Adds the options hostname, prefix and silent to the output of //config: "ipcalc". //applet:IF_IPCALC(APPLET_NOEXEC(ipcalc, ipcalc, BB_DIR_BIN, BB_SUID_DROP, ipcalc)) //kbuild:lib-$(CONFIG_IPCALC) += ipcalc.o //usage:#define ipcalc_trivial_usage //usage: "[-bnm"IF_FEATURE_IPCALC_FANCY("phs")"] ADDRESS" //usage: IF_FEATURE_IPCALC_FANCY("[/PREFIX]") " [NETMASK]" //usage:#define ipcalc_full_usage "\n\n" //usage: "Calculate and display network settings from IP address\n" //usage: "\n -b Broadcast address" //usage: "\n -n Network address" //usage: "\n -m Default netmask for IP" //usage: IF_FEATURE_IPCALC_FANCY( //usage: "\n -p Prefix for IP/NETMASK" //usage: "\n -h Resolved host name" //usage: "\n -s No error messages" //usage: ) #include "libbb.h" /* After libbb.h, because on some systems it needs other includes */ #include #define CLASS_A_NETMASK ntohl(0xFF000000) #define CLASS_B_NETMASK ntohl(0xFFFF0000) #define CLASS_C_NETMASK ntohl(0xFFFFFF00) static unsigned long get_netmask(unsigned long ipaddr) { ipaddr = htonl(ipaddr); if ((ipaddr & 0xC0000000) == 0xC0000000) return CLASS_C_NETMASK; else if ((ipaddr & 0x80000000) == 0x80000000) return CLASS_B_NETMASK; else if ((ipaddr & 0x80000000) == 0) return CLASS_A_NETMASK; else return 0; } #if ENABLE_FEATURE_IPCALC_FANCY static int get_prefix(unsigned long netmask) { unsigned long msk = 0x80000000; int ret = 0; netmask = htonl(netmask); while (msk) { if (netmask & msk) ret++; msk >>= 1; } return ret; } #else int get_prefix(unsigned long netmask); #endif #define NETMASK 0x01 #define BROADCAST 0x02 #define NETWORK 0x04 #define NETPREFIX 0x08 #define HOSTNAME 0x10 #define SILENT 0x20 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS static const char ipcalc_longopts[] ALIGN1 = "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network) "broadcast\0" No_argument "b" // broadcast from IP [netmask] "network\0" No_argument "n" // network from IP [netmask] # if ENABLE_FEATURE_IPCALC_FANCY "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask] "hostname\0" No_argument "h" // hostname from IP "silent\0" No_argument "s" // don’t ever display error messages # endif ; # define GETOPT32 getopt32long # define LONGOPTS ,ipcalc_longopts #else # define GETOPT32 getopt32 # define LONGOPTS #endif int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int ipcalc_main(int argc UNUSED_PARAM, char **argv) { unsigned opt; bool have_netmask = 0; struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr; /* struct in_addr { in_addr_t s_addr; } and in_addr_t * (which in turn is just a typedef to uint32_t) * are essentially the same type. A few macros for less verbosity: */ #define netmask (s_netmask.s_addr) #define broadcast (s_broadcast.s_addr) #define network (s_network.s_addr) #define ipaddr (s_ipaddr.s_addr) char *ipstr; opt = GETOPT32(argv, "^" "mbn" IF_FEATURE_IPCALC_FANCY("phs") "\0" "-1:?2"/*min 1, max 2 args*/ LONGOPTS ); argv += optind; if (opt & SILENT) logmode = LOGMODE_NONE; /* suppress error_msg() output */ opt &= ~SILENT; if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) { /* if no options at all or * (no broadcast,network,prefix) and (two args)... */ if (!opt || argv[1]) bb_show_usage(); } ipstr = argv[0]; if (ENABLE_FEATURE_IPCALC_FANCY) { unsigned long netprefix = 0; char *prefixstr; prefixstr = ipstr; while (*prefixstr) { if (*prefixstr == '/') { *prefixstr++ = '\0'; if (*prefixstr) { unsigned msk; netprefix = xatoul_range(prefixstr, 0, 32); netmask = 0; msk = 0x80000000; while (netprefix > 0) { netmask |= msk; msk >>= 1; netprefix--; } netmask = htonl(netmask); /* Even if it was 0, we will signify that we have a netmask. This allows */ /* for specification of default routes, etc which have a 0 netmask/prefix */ have_netmask = 1; } break; } prefixstr++; } } if (inet_aton(ipstr, &s_ipaddr) == 0) { bb_error_msg_and_die("bad IP address: %s", argv[0]); } if (argv[1]) { if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) { bb_simple_error_msg_and_die("use prefix or netmask, not both"); } if (inet_aton(argv[1], &s_netmask) == 0) { bb_error_msg_and_die("bad netmask: %s", argv[1]); } } else { /* JHC - If the netmask wasn't provided then calculate it */ if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask) netmask = get_netmask(ipaddr); } if (opt & NETMASK) { printf("NETMASK=%s\n", inet_ntoa(s_netmask)); } if (opt & BROADCAST) { broadcast = (ipaddr & netmask) | ~netmask; printf("BROADCAST=%s\n", inet_ntoa(s_broadcast)); } if (opt & NETWORK) { network = ipaddr & netmask; printf("NETWORK=%s\n", inet_ntoa(s_network)); } if (ENABLE_FEATURE_IPCALC_FANCY) { if (opt & NETPREFIX) { printf("PREFIX=%i\n", get_prefix(netmask)); } if (opt & HOSTNAME) { struct hostent *hostinfo; hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET); if (!hostinfo) { bb_herror_msg_and_die("can't find hostname for %s", argv[0]); } str_tolower(hostinfo->h_name); printf("HOSTNAME=%s\n", hostinfo->h_name); } } return EXIT_SUCCESS; }