1 /* $NetBSD: ifconf.c,v 1.1 2014/12/08 04:23:03 ozaki-r Exp $ */
2 /*
3 * Copyright (c) 2014 The NetBSD Foundation, Inc.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __RCSID("$NetBSD: ifconf.c,v 1.1 2014/12/08 04:23:03 ozaki-r Exp $");
29 #include <sys/types.h>
30 #include <sys/socket.h>
31 #include <sys/sockio.h>
32 #include <sys/ioctl.h>
33
34 #include <net/if.h>
35
36 #include <stdio.h>
37 #include <err.h>
38 #include <stdlib.h>
39 #include <unistd.h>
40 #include <string.h>
41
42 static void
help(void)43 help(void)
44 {
45 fprintf(stderr, "usage:\n\t%s total\n\t%s list [<nifreqs>]\n",
46 getprogname(), getprogname());
47 exit(EXIT_FAILURE);
48 }
49
50 static int
get_number_of_entries(void)51 get_number_of_entries(void)
52 {
53 int fd, r;
54 struct ifconf ifc;
55
56 fd = socket(AF_INET, SOCK_DGRAM, 0);
57 if (fd == -1)
58 err(EXIT_FAILURE, "socket");
59
60 ifc.ifc_len = 0;
61 ifc.ifc_buf = NULL;
62
63 r = ioctl(fd, SIOCGIFCONF, &ifc);
64 if (r == -1)
65 err(EXIT_FAILURE, "ioctl");
66
67 close(fd);
68
69 return ifc.ifc_len / sizeof(struct ifreq);
70 }
71
72 static void
show_number_of_entries(void)73 show_number_of_entries(void)
74 {
75 printf("%d\n", get_number_of_entries());
76 }
77
78 static void
show_interfaces(int nifreqs)79 show_interfaces(int nifreqs)
80 {
81 int i, fd, r;
82 struct ifconf ifc;
83 struct ifreq *ifreqs;
84
85 if (nifreqs == 0)
86 nifreqs = get_number_of_entries();
87
88 if (nifreqs <= 0)
89 errx(EXIT_FAILURE, "nifreqs=%d", nifreqs);
90
91 ifreqs = malloc(sizeof(struct ifreq) * nifreqs);
92 if (ifreqs == NULL)
93 err(EXIT_FAILURE, "malloc(sizeof(ifreq) * %d)", nifreqs);
94
95 fd = socket(AF_INET, SOCK_DGRAM, 0);
96 if (fd == -1)
97 err(EXIT_FAILURE, "socket");
98
99 ifc.ifc_len = sizeof(struct ifreq) * nifreqs;
100 ifc.ifc_req = ifreqs;
101
102 r = ioctl(fd, SIOCGIFCONF, &ifc);
103 if (r == -1)
104 err(EXIT_FAILURE, "ioctl");
105 close(fd);
106
107 for (i=0; i < (int)(ifc.ifc_len / sizeof(struct ifreq)); i++) {
108 printf("%s: af=%hhu socklen=%hhu\n", ifreqs[i].ifr_name,
109 ifreqs[i].ifr_addr.sa_family, ifreqs[i].ifr_addr.sa_len);
110 }
111
112 free(ifreqs);
113 }
114
115 int
main(int argc,char * argv[])116 main(int argc, char *argv[])
117 {
118 if (argc < 2)
119 help();
120
121 if (strcmp(argv[1], "total") == 0) {
122 show_number_of_entries();
123 } else if (strcmp(argv[1], "list") == 0) {
124 if (argc == 2)
125 show_interfaces(0);
126 else if (argc == 3)
127 show_interfaces(atoi(argv[2]));
128 else
129 help();
130 } else
131 help();
132
133 return EXIT_SUCCESS;
134 }
135