1 /* vi: set sw=4 ts=4: */
3 * Mini ipcalc implementation for busybox
5 * By Jordan Crouse <jordan@cosmicpenguin.net>
6 * Stephan Linz <linz@li-pro.net>
8 * This is a complete reimplementation of the ipcalc program
9 * from Red Hat. I didn't look at their source code, but there
10 * is no denying that this is a loving reimplementation
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
15 //usage:#define ipcalc_trivial_usage
16 //usage: "[OPTIONS] ADDRESS"
17 //usage: IF_FEATURE_IPCALC_FANCY("[/PREFIX]") " [NETMASK]"
18 //usage:#define ipcalc_full_usage "\n\n"
19 //usage: "Calculate IP network settings from a IP address\n"
20 //usage: IF_FEATURE_IPCALC_LONG_OPTIONS(
21 //usage: "\n -b,--broadcast Display calculated broadcast address"
22 //usage: "\n -n,--network Display calculated network address"
23 //usage: "\n -m,--netmask Display default netmask for IP"
24 //usage: IF_FEATURE_IPCALC_FANCY(
25 //usage: "\n -p,--prefix Display the prefix for IP/NETMASK"
26 //usage: "\n -h,--hostname Display first resolved host name"
27 //usage: "\n -s,--silent Don't ever display error messages"
30 //usage: IF_NOT_FEATURE_IPCALC_LONG_OPTIONS(
31 //usage: "\n -b Display calculated broadcast address"
32 //usage: "\n -n Display calculated network address"
33 //usage: "\n -m Display default netmask for IP"
34 //usage: IF_FEATURE_IPCALC_FANCY(
35 //usage: "\n -p Display the prefix for IP/NETMASK"
36 //usage: "\n -h Display first resolved host name"
37 //usage: "\n -s Don't ever display error messages"
42 /* After libbb.h, because on some systems it needs other includes */
43 #include <arpa/inet.h>
45 #define CLASS_A_NETMASK ntohl(0xFF000000)
46 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
47 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
49 static unsigned long get_netmask(unsigned long ipaddr)
51 ipaddr = htonl(ipaddr);
53 if ((ipaddr & 0xC0000000) == 0xC0000000)
54 return CLASS_C_NETMASK;
55 else if ((ipaddr & 0x80000000) == 0x80000000)
56 return CLASS_B_NETMASK;
57 else if ((ipaddr & 0x80000000) == 0)
58 return CLASS_A_NETMASK;
63 #if ENABLE_FEATURE_IPCALC_FANCY
64 static int get_prefix(unsigned long netmask)
66 unsigned long msk = 0x80000000;
69 netmask = htonl(netmask);
78 int get_prefix(unsigned long netmask);
83 #define BROADCAST 0x02
85 #define NETPREFIX 0x08
89 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
90 static const char ipcalc_longopts[] ALIGN1 =
91 "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
92 "broadcast\0" No_argument "b" // broadcast from IP [netmask]
93 "network\0" No_argument "n" // network from IP [netmask]
94 # if ENABLE_FEATURE_IPCALC_FANCY
95 "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask]
96 "hostname\0" No_argument "h" // hostname from IP
97 "silent\0" No_argument "s" // don’t ever display error messages
102 int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
103 int ipcalc_main(int argc UNUSED_PARAM, char **argv)
106 bool have_netmask = 0;
107 struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
108 /* struct in_addr { in_addr_t s_addr; } and in_addr_t
109 * (which in turn is just a typedef to uint32_t)
110 * are essentially the same type. A few macros for less verbosity: */
111 #define netmask (s_netmask.s_addr)
112 #define broadcast (s_broadcast.s_addr)
113 #define network (s_network.s_addr)
114 #define ipaddr (s_ipaddr.s_addr)
117 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
118 applet_long_options = ipcalc_longopts;
120 opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */
121 opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs"));
124 logmode = LOGMODE_NONE; /* suppress error_msg() output */
126 if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
127 /* if no options at all or
128 * (no broadcast,network,prefix) and (two args)... */
134 if (ENABLE_FEATURE_IPCALC_FANCY) {
135 unsigned long netprefix = 0;
141 if (*prefixstr == '/') {
145 netprefix = xatoul_range(prefixstr, 0, 32);
148 while (netprefix > 0) {
153 netmask = htonl(netmask);
154 /* Even if it was 0, we will signify that we have a netmask. This allows */
155 /* for specification of default routes, etc which have a 0 netmask/prefix */
164 if (inet_aton(ipstr, &s_ipaddr) == 0) {
165 bb_error_msg_and_die("bad IP address: %s", argv[0]);
169 if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
170 bb_error_msg_and_die("use prefix or netmask, not both");
172 if (inet_aton(argv[1], &s_netmask) == 0) {
173 bb_error_msg_and_die("bad netmask: %s", argv[1]);
176 /* JHC - If the netmask wasn't provided then calculate it */
177 if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
178 netmask = get_netmask(ipaddr);
182 printf("NETMASK=%s\n", inet_ntoa(s_netmask));
185 if (opt & BROADCAST) {
186 broadcast = (ipaddr & netmask) | ~netmask;
187 printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
191 network = ipaddr & netmask;
192 printf("NETWORK=%s\n", inet_ntoa(s_network));
195 if (ENABLE_FEATURE_IPCALC_FANCY) {
196 if (opt & NETPREFIX) {
197 printf("PREFIX=%i\n", get_prefix(netmask));
200 if (opt & HOSTNAME) {
201 struct hostent *hostinfo;
203 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
205 bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
207 str_tolower(hostinfo->h_name);
209 printf("HOSTNAME=%s\n", hostinfo->h_name);