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/types.h> 29#include <sys/socket.h> 30#include <net/if_dl.h> 31#include <net/if.h> 32#include <ifaddrs.h> 33#include <stdlib.h> 34#include <string.h> 35 36/* 37 * From RFC 2553: 38 * 39 * 4.3 Return All Interface Names and Indexes 40 * 41 * The if_nameindex structure holds the information about a single 42 * interface and is defined as a result of including the <net/if.h> 43 * header. 44 * 45 * struct if_nameindex { 46 * unsigned int if_index; 47 * char *if_name; 48 * }; 49 * 50 * The final function returns an array of if_nameindex structures, one 51 * structure per interface. 52 * 53 * struct if_nameindex *if_nameindex(void); 54 * 55 * The end of the array of structures is indicated by a structure with 56 * an if_index of 0 and an if_name of NULL. The function returns a NULL 57 * pointer upon an error, and would set errno to the appropriate value. 58 * 59 * The memory used for this array of structures along with the interface 60 * names pointed to by the if_name members is obtained dynamically. 61 * This memory is freed by the next function. 62 * 63 * 4.4. Free Memory 64 * 65 * The following function frees the dynamic memory that was allocated by 66 * if_nameindex(). 67 * 68 * #include <net/if.h> 69 * 70 * void if_freenameindex(struct if_nameindex *ptr); 71 * 72 * The argument to this function must be a pointer that was returned by 73 * if_nameindex(). 74 */ 75 76struct if_nameindex * 77if_nameindex(void) 78{ 79 struct ifaddrs *ifaddrs, *ifa; 80 unsigned int ni; 81 int nbytes; 82 struct if_nameindex *ifni, *ifni2; 83 char *cp; 84 85 if (getifaddrs(&ifaddrs) < 0) 86 return(NULL); 87 88 /* 89 * First, find out how many interfaces there are, and how 90 * much space we need for the string names. 91 */ 92 ni = 0; 93 nbytes = 0; 94 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 95 if (ifa->ifa_addr && 96 ifa->ifa_addr->sa_family == AF_LINK) { 97 nbytes += strlen(ifa->ifa_name) + 1; 98 ni++; 99 } 100 } 101 102 /* 103 * Next, allocate a chunk of memory, use the first part 104 * for the array of structures, and the last part for 105 * the strings. 106 */ 107 cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes); 108 ifni = (struct if_nameindex *)cp; 109 if (ifni == NULL) 110 goto out; 111 cp += (ni + 1) * sizeof(struct if_nameindex); 112 113 /* 114 * Now just loop through the list of interfaces again, 115 * filling in the if_nameindex array and making copies 116 * of all the strings. 117 */ 118 ifni2 = ifni; 119 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 120 if (ifa->ifa_addr && 121 ifa->ifa_addr->sa_family == AF_LINK) { 122 ifni2->if_index = 123 ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index; 124 ifni2->if_name = cp; 125 strcpy(cp, ifa->ifa_name); 126 ifni2++; 127 cp += strlen(cp) + 1; 128 } 129 } 130 /* 131 * Finally, don't forget to terminate the array. 132 */ 133 ifni2->if_index = 0; 134 ifni2->if_name = NULL; 135out: 136 freeifaddrs(ifaddrs); 137 return(ifni); 138} 139 140#ifndef __OpenBSD__ 141void 142if_freenameindex(struct if_nameindex *ptr) 143{ 144 free(ptr); 145} 146#endif 147