blob: 3c8b8bfc910026c270161fd829178d61f7c623f6
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 | |
15 | //usage:#define ipcalc_trivial_usage |
16 | //usage: "[OPTIONS] ADDRESS[[/]NETMASK] [NETMASK]" |
17 | //usage:#define ipcalc_full_usage "\n\n" |
18 | //usage: "Calculate IP network settings from a IP address\n" |
19 | //usage: IF_FEATURE_IPCALC_LONG_OPTIONS( |
20 | //usage: "\n -b,--broadcast Display calculated broadcast address" |
21 | //usage: "\n -n,--network Display calculated network address" |
22 | //usage: "\n -m,--netmask Display default netmask for IP" |
23 | //usage: IF_FEATURE_IPCALC_FANCY( |
24 | //usage: "\n -p,--prefix Display the prefix for IP/NETMASK" |
25 | //usage: "\n -h,--hostname Display first resolved host name" |
26 | //usage: "\n -s,--silent Don't ever display error messages" |
27 | //usage: ) |
28 | //usage: ) |
29 | //usage: IF_NOT_FEATURE_IPCALC_LONG_OPTIONS( |
30 | //usage: "\n -b Display calculated broadcast address" |
31 | //usage: "\n -n Display calculated network address" |
32 | //usage: "\n -m Display default netmask for IP" |
33 | //usage: IF_FEATURE_IPCALC_FANCY( |
34 | //usage: "\n -p Display the prefix for IP/NETMASK" |
35 | //usage: "\n -h Display first resolved host name" |
36 | //usage: "\n -s Don't ever display error messages" |
37 | //usage: ) |
38 | //usage: ) |
39 | |
40 | #include "libbb.h" |
41 | /* After libbb.h, because on some systems it needs other includes */ |
42 | #include <arpa/inet.h> |
43 | |
44 | #define CLASS_A_NETMASK ntohl(0xFF000000) |
45 | #define CLASS_B_NETMASK ntohl(0xFFFF0000) |
46 | #define CLASS_C_NETMASK ntohl(0xFFFFFF00) |
47 | |
48 | static unsigned long get_netmask(unsigned long ipaddr) |
49 | { |
50 | ipaddr = htonl(ipaddr); |
51 | |
52 | if ((ipaddr & 0xC0000000) == 0xC0000000) |
53 | return CLASS_C_NETMASK; |
54 | else if ((ipaddr & 0x80000000) == 0x80000000) |
55 | return CLASS_B_NETMASK; |
56 | else if ((ipaddr & 0x80000000) == 0) |
57 | return CLASS_A_NETMASK; |
58 | else |
59 | return 0; |
60 | } |
61 | |
62 | #if ENABLE_FEATURE_IPCALC_FANCY |
63 | static int get_prefix(unsigned long netmask) |
64 | { |
65 | unsigned long msk = 0x80000000; |
66 | int ret = 0; |
67 | |
68 | netmask = htonl(netmask); |
69 | while (msk) { |
70 | if (netmask & msk) |
71 | ret++; |
72 | msk >>= 1; |
73 | } |
74 | return ret; |
75 | } |
76 | #else |
77 | int get_prefix(unsigned long netmask); |
78 | #endif |
79 | |
80 | |
81 | #define NETMASK 0x01 |
82 | #define BROADCAST 0x02 |
83 | #define NETWORK 0x04 |
84 | #define NETPREFIX 0x08 |
85 | #define HOSTNAME 0x10 |
86 | #define SILENT 0x20 |
87 | |
88 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS |
89 | static const char ipcalc_longopts[] ALIGN1 = |
90 | "netmask\0" No_argument "m" // netmask from IP (assuming complete class A, B, or C network) |
91 | "broadcast\0" No_argument "b" // broadcast from IP [netmask] |
92 | "network\0" No_argument "n" // network from IP [netmask] |
93 | # if ENABLE_FEATURE_IPCALC_FANCY |
94 | "prefix\0" No_argument "p" // prefix from IP[/prefix] [netmask] |
95 | "hostname\0" No_argument "h" // hostname from IP |
96 | "silent\0" No_argument "s" // don’t ever display error messages |
97 | # endif |
98 | ; |
99 | #endif |
100 | |
101 | int ipcalc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
102 | int ipcalc_main(int argc UNUSED_PARAM, char **argv) |
103 | { |
104 | unsigned opt; |
105 | bool have_netmask = 0; |
106 | struct in_addr s_netmask, s_broadcast, s_network, s_ipaddr; |
107 | /* struct in_addr { in_addr_t s_addr; } and in_addr_t |
108 | * (which in turn is just a typedef to uint32_t) |
109 | * are essentially the same type. A few macros for less verbosity: */ |
110 | #define netmask (s_netmask.s_addr) |
111 | #define broadcast (s_broadcast.s_addr) |
112 | #define network (s_network.s_addr) |
113 | #define ipaddr (s_ipaddr.s_addr) |
114 | char *ipstr; |
115 | |
116 | #if ENABLE_FEATURE_IPCALC_LONG_OPTIONS |
117 | applet_long_options = ipcalc_longopts; |
118 | #endif |
119 | opt_complementary = "-1:?2"; /* minimum 1 arg, maximum 2 args */ |
120 | opt = getopt32(argv, "mbn" IF_FEATURE_IPCALC_FANCY("phs")); |
121 | argv += optind; |
122 | if (opt & SILENT) |
123 | logmode = LOGMODE_NONE; /* suppress error_msg() output */ |
124 | opt &= ~SILENT; |
125 | if (!(opt & (BROADCAST | NETWORK | NETPREFIX))) { |
126 | /* if no options at all or |
127 | * (no broadcast,network,prefix) and (two args)... */ |
128 | if (!opt || argv[1]) |
129 | bb_show_usage(); |
130 | } |
131 | |
132 | ipstr = argv[0]; |
133 | if (ENABLE_FEATURE_IPCALC_FANCY) { |
134 | unsigned long netprefix = 0; |
135 | char *prefixstr; |
136 | |
137 | prefixstr = ipstr; |
138 | |
139 | while (*prefixstr) { |
140 | if (*prefixstr == '/') { |
141 | *prefixstr++ = '\0'; |
142 | if (*prefixstr) { |
143 | unsigned msk; |
144 | netprefix = xatoul_range(prefixstr, 0, 32); |
145 | netmask = 0; |
146 | msk = 0x80000000; |
147 | while (netprefix > 0) { |
148 | netmask |= msk; |
149 | msk >>= 1; |
150 | netprefix--; |
151 | } |
152 | netmask = htonl(netmask); |
153 | /* Even if it was 0, we will signify that we have a netmask. This allows */ |
154 | /* for specification of default routes, etc which have a 0 netmask/prefix */ |
155 | have_netmask = 1; |
156 | } |
157 | break; |
158 | } |
159 | prefixstr++; |
160 | } |
161 | } |
162 | |
163 | if (inet_aton(ipstr, &s_ipaddr) == 0) { |
164 | bb_error_msg_and_die("bad IP address: %s", argv[0]); |
165 | } |
166 | |
167 | if (argv[1]) { |
168 | if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) { |
169 | bb_error_msg_and_die("use prefix or netmask, not both"); |
170 | } |
171 | if (inet_aton(argv[1], &s_netmask) == 0) { |
172 | bb_error_msg_and_die("bad netmask: %s", argv[1]); |
173 | } |
174 | } else { |
175 | /* JHC - If the netmask wasn't provided then calculate it */ |
176 | if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask) |
177 | netmask = get_netmask(ipaddr); |
178 | } |
179 | |
180 | if (opt & NETMASK) { |
181 | printf("NETMASK=%s\n", inet_ntoa(s_netmask)); |
182 | } |
183 | |
184 | if (opt & BROADCAST) { |
185 | broadcast = (ipaddr & netmask) | ~netmask; |
186 | printf("BROADCAST=%s\n", inet_ntoa(s_broadcast)); |
187 | } |
188 | |
189 | if (opt & NETWORK) { |
190 | network = ipaddr & netmask; |
191 | printf("NETWORK=%s\n", inet_ntoa(s_network)); |
192 | } |
193 | |
194 | if (ENABLE_FEATURE_IPCALC_FANCY) { |
195 | if (opt & NETPREFIX) { |
196 | printf("PREFIX=%i\n", get_prefix(netmask)); |
197 | } |
198 | |
199 | if (opt & HOSTNAME) { |
200 | struct hostent *hostinfo; |
201 | |
202 | hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET); |
203 | if (!hostinfo) { |
204 | bb_herror_msg_and_die("can't find hostname for %s", argv[0]); |
205 | } |
206 | str_tolower(hostinfo->h_name); |
207 | |
208 | printf("HOSTNAME=%s\n", hostinfo->h_name); |
209 | } |
210 | } |
211 | |
212 | return EXIT_SUCCESS; |
213 | } |
214 |