aboutsummaryrefslogtreecommitdiff
path: root/networking/ipcalc.c
blob: 2a099eff012b4b636dfd4ca61c42efca0089f8f7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/* vi: set sw=4 ts=4: */
/*
 * Mini ipcalc implementation for busybox
 *
 * By Jordan Crouse <jordan@cosmicpenguin.net>
 *    Stephan Linz  <linz@li-pro.net>
 *
 * 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 tarball for details.
 */

#include <getopt.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include "libbb.h"

#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;
}

#ifdef CONFIG_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"
		"broadcast\0" No_argument "b"
		"network\0"   No_argument "n"
# if ENABLE_FEATURE_IPCALC_FANCY
		"prefix\0"    No_argument "p"
		"hostname\0"  No_argument "h"
		"silent\0"    No_argument "s"
# endif
		;
#endif

int ipcalc_main(int argc, char **argv);
int ipcalc_main(int argc, char **argv)
{
	unsigned opt;
	int have_netmask = 0;
	in_addr_t netmask, broadcast, network, ipaddr;
	struct in_addr a;
	char *ipstr;

#if ENABLE_FEATURE_IPCALC_LONG_OPTIONS
	applet_long_options = ipcalc_longopts;
#endif
	opt = getopt32(argc, argv, "mbn" USE_FEATURE_IPCALC_FANCY("phs"));
	argc -= optind;
	argv += optind;
	if (opt & (BROADCAST | NETWORK | NETPREFIX)) {
		if (argc > 2 || argc <= 0)
			bb_show_usage();
	} else {
		if (argc != 1)
			bb_show_usage();
	}
	if (opt & SILENT)
		logmode = LOGMODE_NONE; /* Suppress error_msg() output */

	ipstr = argv[0];
	if (ENABLE_FEATURE_IPCALC_FANCY) {
		unsigned long netprefix = 0;
		char *prefixstr;

		prefixstr = ipstr;

		while (*prefixstr) {
			if (*prefixstr == '/') {
				*prefixstr = (char)0;
				prefixstr++;
				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++;
		}
	}
	ipaddr = inet_aton(ipstr, &a);

	if (ipaddr == 0) {
		bb_error_msg_and_die("bad IP address: %s", argv[0]);
	}
	ipaddr = a.s_addr;

	if (argc == 2) {
		if (ENABLE_FEATURE_IPCALC_FANCY && have_netmask) {
			bb_error_msg_and_die("use prefix or netmask, not both");
		}

		netmask = inet_aton(argv[1], &a);
		if (netmask == 0) {
			bb_error_msg_and_die("bad netmask: %s", argv[1]);
		}
		netmask = a.s_addr;
	} 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((*(struct in_addr *) &netmask)));
	}

	if (opt & BROADCAST) {
		broadcast = (ipaddr & netmask) | ~netmask;
		printf("BROADCAST=%s\n", inet_ntoa((*(struct in_addr *) &broadcast)));
	}

	if (opt & NETWORK) {
		network = ipaddr & netmask;
		printf("NETWORK=%s\n", inet_ntoa((*(struct in_addr *) &network)));
	}

	if (ENABLE_FEATURE_IPCALC_FANCY) {
		if (opt & NETPREFIX) {
			printf("PREFIX=%i\n", get_prefix(netmask));
		}

		if (opt & HOSTNAME) {
			struct hostent *hostinfo;
			int x;

			hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
			if (!hostinfo) {
				bb_herror_msg_and_die("cannot find hostname for %s", argv[0]);
			}
			for (x = 0; hostinfo->h_name[x]; x++) {
				hostinfo->h_name[x] = tolower(hostinfo->h_name[x]);
			}

			printf("HOSTNAME=%s\n", hostinfo->h_name);
		}
	}

	return EXIT_SUCCESS;
}