1 /* $NetBSD: if_nameindex.c,v 1.7 2012/03/13 21:13:41 christos Exp $ */
2 /* $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $ */
3
4 /*-
5 * Copyright (c) 1997, 2000
6 * Berkeley Software Design, Inc. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
27 */
28
29 #include <sys/cdefs.h>
30 #if defined(LIBC_SCCS) && !defined(lint)
31 __RCSID("$NetBSD: if_nameindex.c,v 1.7 2012/03/13 21:13:41 christos Exp $");
32 #endif /* LIBC_SCCS and not lint */
33
34 #include "namespace.h"
35 #include <sys/types.h>
36 #include <sys/socket.h>
37 #include <net/if_dl.h>
38 #include <net/if.h>
39 #include <ifaddrs.h>
40 #include <stdlib.h>
41 #include <string.h>
42
43 #ifdef __weak_alias
__weak_alias(if_nameindex,_if_nameindex)44 __weak_alias(if_nameindex,_if_nameindex)
45 __weak_alias(if_freenameindex,_if_freenameindex)
46 #endif
47 /*
48 * From RFC 2553:
49 *
50 * 4.3 Return All Interface Names and Indexes
51 *
52 * The if_nameindex structure holds the information about a single
53 * interface and is defined as a result of including the <net/if.h>
54 * header.
55 *
56 * struct if_nameindex {
57 * unsigned int if_index;
58 * char *if_name;
59 * };
60 *
61 * The final function returns an array of if_nameindex structures, one
62 * structure per interface.
63 *
64 * struct if_nameindex *if_nameindex(void);
65 *
66 * The end of the array of structures is indicated by a structure with
67 * an if_index of 0 and an if_name of NULL. The function returns a NULL
68 * pointer upon an error, and would set errno to the appropriate value.
69 *
70 * The memory used for this array of structures along with the interface
71 * names pointed to by the if_name members is obtained dynamically.
72 * This memory is freed by the next function.
73 *
74 * 4.4. Free Memory
75 *
76 * The following function frees the dynamic memory that was allocated by
77 * if_nameindex().
78 *
79 * #include <net/if.h>
80 *
81 * void if_freenameindex(struct if_nameindex *ptr);
82 *
83 * The argument to this function must be a pointer that was returned by
84 * if_nameindex().
85 */
86
87 struct if_nameindex *
88 if_nameindex(void)
89 {
90 struct ifaddrs *ifaddrs, *ifa;
91 size_t nbytes, ni;
92 struct if_nameindex *ifni, *ifni2;
93 char *cp;
94
95 if (getifaddrs(&ifaddrs) < 0)
96 return(NULL);
97
98 /*
99 * First, find out how many interfaces there are, and how
100 * much space we need for the string names.
101 */
102 ni = 0;
103 nbytes = 0;
104 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
105 if (ifa->ifa_addr &&
106 ifa->ifa_addr->sa_family == AF_LINK) {
107 nbytes += strlen(ifa->ifa_name) + 1;
108 ni++;
109 }
110 }
111
112 /*
113 * Next, allocate a chunk of memory, use the first part
114 * for the array of structures, and the last part for
115 * the strings.
116 */
117 cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes);
118 ifni = (struct if_nameindex *)(void *)cp;
119 if (ifni == NULL)
120 goto out;
121 cp += (ni + 1) * sizeof(struct if_nameindex);
122
123 /*
124 * Now just loop through the list of interfaces again,
125 * filling in the if_nameindex array and making copies
126 * of all the strings.
127 */
128 ifni2 = ifni;
129 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
130 if (ifa->ifa_addr &&
131 ifa->ifa_addr->sa_family == AF_LINK) {
132 ifni2->if_index =
133 ((struct sockaddr_dl*)
134 (void *)ifa->ifa_addr)->sdl_index;
135 ifni2->if_name = cp;
136 strcpy(cp, ifa->ifa_name);
137 ifni2++;
138 cp += strlen(cp) + 1;
139 }
140 }
141 /*
142 * Finally, don't forget to terminate the array.
143 */
144 ifni2->if_index = 0;
145 ifni2->if_name = NULL;
146 out:
147 freeifaddrs(ifaddrs);
148 return(ifni);
149 }
150
151 void
if_freenameindex(struct if_nameindex * ptr)152 if_freenameindex(struct if_nameindex *ptr)
153 {
154 free(ptr);
155 }
156