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 tarball for details.
13 */
14
15#include <getopt.h>
16#include <sys/socket.h>
17#include <arpa/inet.h>
18
19#include "libbb.h"
20
21#define CLASS_A_NETMASK	ntohl(0xFF000000)
22#define CLASS_B_NETMASK	ntohl(0xFFFF0000)
23#define CLASS_C_NETMASK	ntohl(0xFFFFFF00)
24
25static unsigned long get_netmask(unsigned long ipaddr)
26{
27	ipaddr = htonl(ipaddr);
28
29	if ((ipaddr & 0xC0000000) == 0xC0000000)
30		return CLASS_C_NETMASK;
31	else if ((ipaddr & 0x80000000) == 0x80000000)
32		return CLASS_B_NETMASK;
33	else if ((ipaddr & 0x80000000) == 0)
34		return CLASS_A_NETMASK;
35	else
36		return 0;
37}
38
39#if ENABLE_FEATURE_IPCALC_FANCY
40static int get_prefix(unsigned long netmask)
41{
42	unsigned long msk = 0x80000000;
43	int ret = 0;
44
45	netmask = htonl(netmask);
46	while (msk) {
47		if (netmask & msk)
48			ret++;
49		msk >>= 1;
50	}
51	return ret;
52}
53#else
54int get_prefix(unsigned long netmask);
55#endif
56
57
58#define NETMASK   0x01
59#define BROADCAST 0x02
60#define NETWORK   0x04
61#define NETPREFIX 0x08
62#define HOSTNAME  0x10
63#define SILENT    0x20
64
65#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
66	static const char ipcalc_longopts[] ALIGN1 =
67		"netmask\0"   No_argument "m"
68		"broadcast\0" No_argument "b"
69		"network\0"   No_argument "n"
70# if ENABLE_FEATURE_IPCALC_FANCY
71		"prefix\0"    No_argument "p"
72		"hostname\0"  No_argument "h"
73		"silent\0"    No_argument "s"
74# endif
75		;
76#endif
77
78int ipcalc_main(int argc, char **argv);
79int ipcalc_main(int argc, char **argv)
80{
81	unsigned opt;
82	int have_netmask = 0;
83	in_addr_t netmask, broadcast, network, ipaddr;
84	struct in_addr a;
85	char *ipstr;
86
87#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
88	applet_long_options = ipcalc_longopts;
89#endif
90	opt = getopt32(argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
91	argc -= optind;
92	argv += optind;
93	if (opt & (BROADCAST | NETWORK | NETPREFIX)) {
94		if (argc > 2 || argc <= 0)
95			bb_show_usage();
96	} else {
97		if (argc != 1)
98			bb_show_usage();
99	}
100	if (opt & SILENT)
101		logmode = LOGMODE_NONE; /* Suppress error_msg() output */
102
103	ipstr = argv[0];
104	if (ENABLE_FEATURE_IPCALC_FANCY) {
105		unsigned long netprefix = 0;
106		char *prefixstr;
107
108		prefixstr = ipstr;
109
110		while (*prefixstr) {
111			if (*prefixstr == '/') {
112				*prefixstr = (char)0;
113				prefixstr++;
114				if (*prefixstr) {
115					unsigned msk;
116					netprefix = xatoul_range(prefixstr, 0, 32);
117					netmask = 0;
118					msk = 0x80000000;
119					while (netprefix > 0) {
120						netmask |= msk;
121						msk >>= 1;
122						netprefix--;
123					}
124					netmask = htonl(netmask);
125					/* Even if it was 0, we will signify that we have a netmask. This allows */
126					/* for specification of default routes, etc which have a 0 netmask/prefix */
127					have_netmask = 1;
128				}
129				break;
130			}
131			prefixstr++;
132		}
133	}
134	ipaddr = inet_aton(ipstr, &a);
135
136	if (ipaddr == 0) {
137		bb_error_msg_and_die("bad IP address: %s", argv[0]);
138	}
139	ipaddr = a.s_addr;
140
141	if (argc == 2) {
142		if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
143			bb_error_msg_and_die("use prefix or netmask, not both");
144		}
145
146		netmask = inet_aton(argv[1], &a);
147		if (netmask == 0) {
148			bb_error_msg_and_die("bad netmask: %s", argv[1]);
149		}
150		netmask = a.s_addr;
151	} else {
152
153		/* JHC - If the netmask wasn't provided then calculate it */
154		if (!ENABLE_FEATURE_IPCALC_FANCY || !have_netmask)
155			netmask = get_netmask(ipaddr);
156	}
157
158	if (opt & NETMASK) {
159		printf("NETMASK=%s\n", inet_ntoa((*(struct in_addr *) &netmask)));
160	}
161
162	if (opt & BROADCAST) {
163		broadcast = (ipaddr & netmask) | ~netmask;
164		printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
165	}
166
167	if (opt & NETWORK) {
168		network = ipaddr & netmask;
169		printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
170	}
171
172	if (ENABLE_FEATURE_IPCALC_FANCY) {
173		if (opt & NETPREFIX) {
174			printf("PREFIX=%i\n", get_prefix(netmask));
175		}
176
177		if (opt & HOSTNAME) {
178			struct hostent *hostinfo;
179			int x;
180
181			hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
182			if (!hostinfo) {
183				bb_herror_msg_and_die("cannot find hostname for %s", argv[0]);
184			}
185			for (x = 0; hostinfo->h_name[x]; x++) {
186				hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
187			}
188
189			printf("HOSTNAME=%s\n", hostinfo->h_name);
190		}
191	}
192
193	return EXIT_SUCCESS;
194}
195