1 /* $KAME: if_nameindex.c,v 1.8 2000/11/24 08:20:01 itojun Exp $ */
2
3 /*-
4 * Copyright (c) 1997, 2000
5 * Berkeley Software Design, Inc. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
26 *
27 * $FreeBSD: src/lib/libc/net/if_nameindex.c,v 1.1.2.1 2002/07/29 18:33:18 ume Exp $
28 * $DragonFly: src/lib/libc/net/if_nameindex.c,v 1.2 2003/06/17 04:26:44 dillon Exp $
29 */
30
31 #include <sys/types.h>
32 #include <sys/socket.h>
33 #include <net/if_dl.h>
34 #include <net/if.h>
35 #include <ifaddrs.h>
36 #include <stdlib.h>
37 #include <string.h>
38
39 /*
40 * From RFC 2553:
41 *
42 * 4.3 Return All Interface Names and Indexes
43 *
44 * The if_nameindex structure holds the information about a single
45 * interface and is defined as a result of including the <net/if.h>
46 * header.
47 *
48 * struct if_nameindex {
49 * unsigned int if_index;
50 * char *if_name;
51 * };
52 *
53 * The final function returns an array of if_nameindex structures, one
54 * structure per interface.
55 *
56 * struct if_nameindex *if_nameindex(void);
57 *
58 * The end of the array of structures is indicated by a structure with
59 * an if_index of 0 and an if_name of NULL. The function returns a NULL
60 * pointer upon an error, and would set errno to the appropriate value.
61 *
62 * The memory used for this array of structures along with the interface
63 * names pointed to by the if_name members is obtained dynamically.
64 * This memory is freed by the next function.
65 *
66 * 4.4. Free Memory
67 *
68 * The following function frees the dynamic memory that was allocated by
69 * if_nameindex().
70 *
71 * #include <net/if.h>
72 *
73 * void if_freenameindex(struct if_nameindex *ptr);
74 *
75 * The argument to this function must be a pointer that was returned by
76 * if_nameindex().
77 */
78
79 struct if_nameindex *
if_nameindex(void)80 if_nameindex(void)
81 {
82 struct ifaddrs *ifaddrs, *ifa;
83 unsigned int ni;
84 int nbytes;
85 struct if_nameindex *ifni, *ifni2;
86 char *cp;
87
88 if (getifaddrs(&ifaddrs) < 0)
89 return(NULL);
90
91 /*
92 * First, find out how many interfaces there are, and how
93 * much space we need for the string names.
94 */
95 ni = 0;
96 nbytes = 0;
97 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
98 if (ifa->ifa_addr &&
99 ifa->ifa_addr->sa_family == AF_LINK) {
100 nbytes += strlen(ifa->ifa_name) + 1;
101 ni++;
102 }
103 }
104
105 /*
106 * Next, allocate a chunk of memory, use the first part
107 * for the array of structures, and the last part for
108 * the strings.
109 */
110 cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes);
111 ifni = (struct if_nameindex *)cp;
112 if (ifni == NULL)
113 goto out;
114 cp += (ni + 1) * sizeof(struct if_nameindex);
115
116 /*
117 * Now just loop through the list of interfaces again,
118 * filling in the if_nameindex array and making copies
119 * of all the strings.
120 */
121 ifni2 = ifni;
122 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
123 if (ifa->ifa_addr &&
124 ifa->ifa_addr->sa_family == AF_LINK) {
125 ifni2->if_index =
126 ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
127 ifni2->if_name = cp;
128 strcpy(cp, ifa->ifa_name);
129 ifni2++;
130 cp += strlen(cp) + 1;
131 }
132 }
133 /*
134 * Finally, don't forget to terminate the array.
135 */
136 ifni2->if_index = 0;
137 ifni2->if_name = NULL;
138 out:
139 freeifaddrs(ifaddrs);
140 return(ifni);
141 }
142
143 void
if_freenameindex(struct if_nameindex * ptr)144 if_freenameindex(struct if_nameindex *ptr)
145 {
146 free(ptr);
147 }
148