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