1 /* vi: set sw=4 ts=4: */
2 /*
3 * Mini ipcalc implementation for busybox
4 *
5 * By Jordan Crouse <jordan@cosmicpenguin.net>
6 * Stephan Linz <linz@li-pro.net>
7 *
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
11 *
12 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
13 */
14 //config:config IPCALC
15 //config: bool "ipcalc (4.4 kb)"
16 //config: default y
17 //config: help
18 //config: ipcalc takes an IP address and netmask and calculates the
19 //config: resulting broadcast, network, and host range.
20 //config:
21 //config:config FEATURE_IPCALC_LONG_OPTIONS
22 //config: bool "Enable long options"
23 //config: default y
24 //config: depends on IPCALC && LONG_OPTS
25 //config:
26 //config:config FEATURE_IPCALC_FANCY
27 //config: bool "Fancy IPCALC, more options, adds 1 kbyte"
28 //config: default y
29 //config: depends on IPCALC
30 //config: help
31 //config: Adds the options hostname, prefix and silent to the output of
32 //config: "ipcalc".
33
34 //applet:IF_IPCALC(APPLET_NOEXEC(ipcalc, ipcalc, BB_DIR_BIN, BB_SUID_DROP, ipcalc))
35
36 //kbuild:lib-$(CONFIG_IPCALC) += ipcalc.o
37
38 //usage:#define ipcalc_trivial_usage
39 //usage: "[-bnm"IF_FEATURE_IPCALC_FANCY("phs")"] ADDRESS"
40 //usage: IF_FEATURE_IPCALC_FANCY("[/PREFIX]") " [NETMASK]"
41 //usage:#define ipcalc_full_usage "\n\n"
42 //usage: "Calculate and display network settings from IP address\n"
43 //usage: "\n -b Broadcast address"
44 //usage: "\n -n Network address"
45 //usage: "\n -m Default netmask for IP"
46 //usage: IF_FEATURE_IPCALC_FANCY(
47 //usage: "\n -p Prefix for IP/NETMASK"
48 //usage: "\n -h Resolved host name"
49 //usage: "\n -s No error messages"
50 //usage: )
51
52 #include "libbb.h"
53 /* After libbb.h, because on some systems it needs other includes */
54 #include <arpa/inet.h>
55
56 #define CLASS_A_NETMASK ntohl(0xFF000000)
57 #define CLASS_B_NETMASK ntohl(0xFFFF0000)
58 #define CLASS_C_NETMASK ntohl(0xFFFFFF00)
59
get_netmask(unsigned long ipaddr)60 static unsigned long get_netmask(unsigned long ipaddr)
61 {
62 ipaddr = htonl(ipaddr);
63
64 if ((ipaddr & 0xC0000000) == 0xC0000000)
65 return CLASS_C_NETMASK;
66 else if ((ipaddr & 0x80000000) == 0x80000000)
67 return CLASS_B_NETMASK;
68 else if ((ipaddr & 0x80000000) == 0)
69 return CLASS_A_NETMASK;
70 else
71 return 0;
72 }
73
74 #if ENABLE_FEATURE_IPCALC_FANCY
get_prefix(unsigned long netmask)75 static int get_prefix(unsigned long netmask)
76 {
77 unsigned long msk = 0x80000000;
78 int ret = 0;
79
80 netmask = htonl(netmask);
81 while (msk) {
82 if (netmask & msk)
83 ret++;
84 msk >>= 1;
85 }
86 return ret;
87 }
88 #else
89 int get_prefix(unsigned long netmask);
90 #endif
91
92
93 #define NETMASK 0x01
94 #define BROADCAST 0x02
95 #define NETWORK 0x04
96 #define NETPREFIX 0x08
97 #define HOSTNAME 0x10
98 #define SILENT 0x20
99
100 #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
101 static const char ipcalc_longopts[] ALIGN1 =
102 "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network)
103 "broadcast\0" No_argument "b" // broadcast from IP [netmask]
104 "network\0" No_argument "n" // network from IP [netmask]
105 # if ENABLE_FEATURE_IPCALC_FANCY
106 "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask]
107 "hostname\0" No_argument "h" // hostname from IP
108 "silent\0" No_argument "s" // don’t ever display error messages
109 # endif
110 ;
111 # define GETOPT32 getopt32long
112 # define LONGOPTS ,ipcalc_longopts
113 #else
114 # define GETOPT32 getopt32
115 # define LONGOPTS
116 #endif
117
118 int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
ipcalc_main(int argc UNUSED_PARAM,char ** argv)119 int ipcalc_main(int argc UNUSED_PARAM, char **argv)
120 {
121 unsigned opt;
122 bool have_netmask = 0;
123 struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr;
124 /* struct in_addr { in_addr_t s_addr; } and in_addr_t
125 * (which in turn is just a typedef to uint32_t)
126 * are essentially the same type. A few macros for less verbosity: */
127 #define netmask (s_netmask.s_addr)
128 #define broadcast (s_broadcast.s_addr)
129 #define network (s_network.s_addr)
130 #define ipaddr (s_ipaddr.s_addr)
131 char *ipstr;
132
133 opt = GETOPT32(argv, "^"
134 "mbn" IF_FEATURE_IPCALC_FANCY("phs")
135 "\0" "-1:?2"/*min 1, max 2 args*/
136 LONGOPTS
137 );
138 argv += optind;
139 if (opt & SILENT)
140 logmode = LOGMODE_NONE; /* suppress error_msg() output */
141 opt &= ~SILENT;
142 if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) {
143 /* if no options at all or
144 * (no broadcast,network,prefix) and (two args)... */
145 if (!opt || argv[1])
146 bb_show_usage();
147 }
148
149 ipstr = argv[0];
150 if (ENABLE_FEATURE_IPCALC_FANCY) {
151 unsigned long netprefix = 0;
152 char *prefixstr;
153
154 prefixstr = ipstr;
155
156 while (*prefixstr) {
157 if (*prefixstr == '/') {
158 *prefixstr++ = '\0';
159 if (*prefixstr) {
160 unsigned msk;
161 netprefix = xatoul_range(prefixstr, 0, 32);
162 netmask = 0;
163 msk = 0x80000000;
164 while (netprefix > 0) {
165 netmask |= msk;
166 msk >>= 1;
167 netprefix--;
168 }
169 netmask = htonl(netmask);
170 /* Even if it was 0, we will signify that we have a netmask. This allows */
171 /* for specification of default routes, etc which have a 0 netmask/prefix */
172 have_netmask = 1;
173 }
174 break;
175 }
176 prefixstr++;
177 }
178 }
179
180 if (inet_aton(ipstr, &s_ipaddr) == 0) {
181 bb_error_msg_and_die("bad IP address: %s", argv[0]);
182 }
183
184 if (argv[1]) {
185 if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
186 bb_simple_error_msg_and_die("use prefix or netmask, not both");
187 }
188 if (inet_aton(argv[1], &s_netmask) == 0) {
189 bb_error_msg_and_die("bad netmask: %s", argv[1]);
190 }
191 } else {
192 /* JHC - If the netmask wasn't provided then calculate it */
193 if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
194 netmask = get_netmask(ipaddr);
195 }
196
197 if (opt & NETMASK) {
198 printf("NETMASK=%s\n", inet_ntoa(s_netmask));
199 }
200
201 if (opt & BROADCAST) {
202 broadcast = (ipaddr & netmask) | ~netmask;
203 printf("BROADCAST=%s\n", inet_ntoa(s_broadcast));
204 }
205
206 if (opt & NETWORK) {
207 network = ipaddr & netmask;
208 printf("NETWORK=%s\n", inet_ntoa(s_network));
209 }
210
211 if (ENABLE_FEATURE_IPCALC_FANCY) {
212 if (opt & NETPREFIX) {
213 printf("PREFIX=%i\n", get_prefix(netmask));
214 }
215
216 if (opt & HOSTNAME) {
217 struct hostent *hostinfo;
218
219 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
220 if (!hostinfo) {
221 bb_herror_msg_and_die("can't find hostname for %s", argv[0]);
222 }
223 str_tolower(hostinfo->h_name);
224
225 printf("HOSTNAME=%s\n", hostinfo->h_name);
226 }
227 }
228
229 return EXIT_SUCCESS;
230 }
231