1/*	$NetBSD: if_nameindex.c,v 1.6 2000/12/20 18:47:11 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 1.6 2000/12/20 18:47:11 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
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
87struct if_nameindex *
88if_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;
146out:
147	freeifaddrs(ifaddrs);
148	return(ifni);
149}
150
151void
152if_freenameindex(struct if_nameindex *ptr)
153{
154	free(ptr);
155}
156