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
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
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
79struct if_nameindex *
80if_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			    LLINDEX((struct sockaddr_dl*)ifa->ifa_addr);
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;
138out:
139	freeifaddrs(ifaddrs);
140	return(ifni);
141}
142
143void
144if_freenameindex(struct if_nameindex *ptr)
145{
146	free(ptr);
147}
148