1 /* 2 * Copyright (c) 1998-1999, Craig Metz, All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. All advertising materials mentioning features or use of this software 13 * must display the following acknowledgement: 14 * This product includes software developed by Craig Metz and 15 * by other contributors. 16 * 4. Neither the name of the author nor the names of contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <stdlib.h> 34 #include <sys/types.h> 35 #include <sys/socket.h> 36 #include <sys/ioctl.h> 37 #include <net/if.h> 38 #include <net/if_dl.h> 39 #include <errno.h> 40 #include <unistd.h> 41 #include <string.h> 42 43 struct if_nameindex * 44 if_nameindex(void) 45 { 46 int i, j, fd = -1, extra, len = 0; 47 struct if_nameindex *nameindex = NULL; 48 struct ifconf ifconf; 49 char lastname[IFNAMSIZ], *c, *inbuf; 50 struct if_nameindex *n; 51 struct sockaddr *sa; 52 void *p; 53 54 ifconf.ifc_buf = NULL; 55 56 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) 57 goto ret; 58 59 /* 60 * Try ifc_len == 0 hack first, to get the actual length. 61 * If that fails, revert to a loop which grows the ifc_buf 62 * until it is sufficiently large. 63 */ 64 extra = sizeof(struct ifreq); 65 while (1) { 66 ifconf.ifc_len = len; 67 if (ioctl(fd, SIOCGIFCONF, (void *) &ifconf) == -1 && 68 ifconf.ifc_buf) 69 goto ret; 70 if (ifconf.ifc_buf && 71 ifconf.ifc_len + extra < len) 72 break; 73 if (ifconf.ifc_buf) { 74 if (len == 0) 75 len = 4096; 76 ifconf.ifc_len = len *= 2; 77 } else { 78 len = ifconf.ifc_len; 79 extra = 0; 80 } 81 inbuf = realloc(ifconf.ifc_buf, ifconf.ifc_len); 82 if (inbuf == NULL) 83 goto ret; 84 ifconf.ifc_buf = inbuf; 85 } 86 87 i = sizeof(struct if_nameindex); 88 j = 0; 89 p = ifconf.ifc_buf; 90 len = ifconf.ifc_len; 91 lastname[0] = 0; 92 lastname[sizeof(lastname)-1] = 0; 93 94 while (len > 0) { 95 if (len < (IFNAMSIZ + sizeof(struct sockaddr))) 96 goto ret; 97 if (strncmp(lastname, p, IFNAMSIZ)) { 98 strlcpy(lastname, p, sizeof(lastname)); 99 i += sizeof(struct if_nameindex); 100 j += strlen(lastname) + 1; 101 } 102 len -= IFNAMSIZ; 103 p += IFNAMSIZ; 104 sa = p; 105 106 if (len < sa->sa_len) 107 goto ret; 108 len -= sa->sa_len; 109 p += sa->sa_len; 110 } 111 112 nameindex = malloc(i + j); 113 if (nameindex == NULL) { 114 errno = ENOMEM; 115 goto ret; 116 } 117 memset(nameindex, 0, i + j); 118 119 n = nameindex; 120 p = ifconf.ifc_buf; 121 c = (void *) nameindex + i; 122 i = 0; 123 len = ifconf.ifc_len; 124 lastname[0] = 0; 125 126 while (len > 0) { 127 if (len < IFNAMSIZ + sizeof(struct sockaddr)) 128 goto ret; 129 if (strncmp(lastname, p, IFNAMSIZ)) { 130 if (i) { 131 if (!n->if_index) 132 n->if_index = i; 133 n++; 134 } 135 i++; 136 memcpy(lastname, p, sizeof(lastname)); 137 strlcpy(c, lastname, sizeof(lastname)); 138 n->if_name = c; 139 c += strlen(c) + 1; 140 } 141 len -= IFNAMSIZ; 142 p += IFNAMSIZ; 143 sa = p; 144 145 if (len < sa->sa_len) 146 goto ret; 147 if (sa->sa_family == AF_LINK) { 148 struct sockaddr_dl *sd = (struct sockaddr_dl *)sa; 149 n->if_index = sd->sdl_index; 150 } 151 len -= sa->sa_len; 152 p += sa->sa_len; 153 } 154 155 if (n->if_index == 0) 156 n->if_index = i; 157 158 ret: 159 if (fd != -1) 160 close(fd); 161 if (ifconf.ifc_buf) 162 free(ifconf.ifc_buf); 163 return (nameindex); 164 } 165