1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <string.h> 30 #include <unistd.h> 31 #include <linux/sockios.h> 32 #include <net/if.h> 33 #include <sys/socket.h> 34 #include <sys/ioctl.h> 35 36 /* 37 * Map an interface name into its corresponding index. 38 * Returns 0 on error, as 0 is not a valid index. 39 */ 40 unsigned int if_nametoindex(const char *ifname) 41 { 42 int index; 43 int ctl_sock; 44 struct ifreq ifr; 45 46 memset(&ifr, 0, sizeof(struct ifreq)); 47 strncpy(ifr.ifr_name, ifname, IFNAMSIZ); 48 ifr.ifr_name[IFNAMSIZ - 1] = 0; 49 50 index = 0; 51 if ((ctl_sock = socket(AF_INET, SOCK_DGRAM, 0)) >= 0) { 52 if (ioctl(ctl_sock, SIOCGIFINDEX, &ifr) >= 0) { 53 index = ifr.ifr_ifindex; 54 } 55 close(ctl_sock); 56 } 57 return index; 58 } 59
