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