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 79 struct if_nameindex * 80 if_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; 138 out: 139 freeifaddrs(ifaddrs); 140 return(ifni); 141 } 142 143 void 144 if_freenameindex(struct if_nameindex *ptr) 145 { 146 free(ptr); 147 } 148