1/* @(#) interface/address conversion 2 * 3 * Copyright 2008-2011 Pavel V. Cherenkov (pcherenkov@gmail.com) 4 * 5 * This file is part of udpxy. 6 * 7 * udpxy is free software: you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation, either version 3 of the License, or 10 * (at your option) any later version. 11 * 12 * udpxy is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with udpxy. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 22#include <sys/socket.h> 23#include <sys/ioctl.h> 24#include <sys/types.h> 25#include <string.h> 26#include <unistd.h> 27#include <errno.h> 28#include <net/if.h> 29#include <stdlib.h> 30#include <netinet/in.h> 31#include <arpa/inet.h> 32 33#include <assert.h> 34#include <limits.h> 35 36#include "osdef.h" 37#include "ifaddr.h" 38 39 40/* check if ifr contains info on the desired ifname 41 */ 42static int 43chkifr( const struct ifreq* ifr, const char* ifname, 44 const size_t addrlen, size_t* offset ) 45{ 46 size_t sa_len = 0; 47 48 assert(ifr && ifname && offset); 49 50#ifdef NO_SOCKADDR_SA_LEN 51 switch( ifr->ifr_addr.sa_family ) 52 { 53 #ifndef NO_INET6_SUPPORT 54 case AF_INET6: sa_len = sizeof(struct sockaddr_in6); break; 55 #endif 56 case AF_INET: sa_len = sizeof(struct sockaddr); break; 57 default: sa_len = 0; break; 58 } 59#else 60 sa_len = ifr->ifr_addr.sa_len; 61#endif 62 63 if( sa_len > 0 ) { 64 if ( (ifr->ifr_addr.sa_family == AF_INET) && 65 (0 == strncmp(ifname, ifr->ifr_name, sizeof(struct ifreq))) && 66 (addrlen >= sa_len) ) { 67 *offset = sa_len; 68 return 0; 69 } 70 } 71 72#if defined(__linux) 73 *offset = sizeof(*ifr); 74#else 75 *offset = (sa_len + sizeof( ifr->ifr_name )); 76 /* the above is per R. Stevens' book and not working on 64-bit Linux */ 77#endif 78 79 return -1; 80} 81 82 83 84/* retrieve IPv4 address of the given network interface 85 */ 86int 87if2addr( const char* ifname, 88 struct sockaddr *addr, size_t addrlen ) 89{ 90 int rc, sockfd; 91 char *buf, *rec; 92 size_t buflen, offset; 93 int last_len; 94 struct ifconf ifc; 95 struct ifreq ifr; 96 97 static size_t IFC_TABLE_SIZE; 98 99 static const size_t IFC_ENTRIES = 32; 100 static const size_t MAX_IFCBUF_SIZE = (1024 * 256); 101 102 IFC_TABLE_SIZE = sizeof(struct ifreq) * IFC_ENTRIES; 103 104 assert( ifname && addr && addrlen ); 105 rc = 0; 106 107 /* acquire the list of network interfaces */ 108 109 sockfd = socket( AF_INET, SOCK_DGRAM, 0 ); 110 if( -1 == sockfd ) return -1; 111 112 buf = NULL; buflen = IFC_TABLE_SIZE; last_len = 0; 113 for( ; buflen < MAX_IFCBUF_SIZE; buflen += IFC_TABLE_SIZE ) { 114 if( NULL == (buf = malloc( buflen )) ) { 115 rc = -1; 116 break; 117 } 118 119 ifc.ifc_len = buflen; 120 ifc.ifc_buf = buf; 121 if( ioctl( sockfd, SIOCGIFCONF, &ifc ) < 0 ) { 122 if( (EINVAL != errno) || (last_len != 0) ) { 123 rc = errno; 124 break; 125 } 126 } 127 else { 128 if( ifc.ifc_len == last_len ) 129 break; 130 else 131 last_len = ifc.ifc_len; 132 } 133 134 free( buf ); 135 buf = NULL; 136 } /* for */ 137 138 (void) close( sockfd ); 139 if( buflen > MAX_IFCBUF_SIZE ) rc = -1; 140 141 if( 0 != rc ) { 142 if( NULL != buf ) free( buf ); 143 return rc; 144 } 145 146 assert( ifc.ifc_buf ); 147 148 /* look for ifname in the list */ 149 150 for( rec = ifc.ifc_buf; rec < (ifc.ifc_buf + ifc.ifc_len); ) { 151 (void) memcpy( &ifr, rec, sizeof(struct ifreq) ); 152 153 offset = 0; 154 rc = chkifr( &ifr, ifname, addrlen, &offset ); 155 if ( 0 == rc ) { 156 (void) memcpy( addr, &(ifr.ifr_addr), offset ); 157 break; 158 } 159 160 if( 0 == offset ) break; 161 rec += offset; 162 } /* for */ 163 164 if( rec >= (buf + ifc.ifc_len) ) { 165 rc = -1; 166 } 167 168 free( buf ); 169 return rc; 170} 171 172 173/* convert input parameter into an IPv4-address string 174 */ 175int 176get_ipv4_address( const char* s, char* buf, size_t len ) 177{ 178 struct sockaddr_in saddr; 179 int rc = 0; 180 181 assert( s && buf && len ); 182 183 if( 1 == inet_aton(s, &(saddr.sin_addr)) ) { 184 (void) strncpy( buf, s, len ); 185 } 186 else { 187 rc = if2addr( s, (struct sockaddr*)&saddr, sizeof(saddr) ); 188 if( 0 != rc ) return rc; 189 190 (void) strncpy( buf, inet_ntoa(saddr.sin_addr), len ); 191 } 192 193 buf[ len - 1 ] = 0; 194 return rc; 195} 196 197 198/* split input string into IP address and port 199 */ 200int 201get_addrport( const char* s, char* addr, size_t len, int* port ) 202{ 203 struct sockaddr_in saddr; 204 size_t i = 0; 205 int iport = 0; 206 207 static const int ERR_NOPORT = -1; 208 static const int ERR_BADADDR = -2; 209 static const int ERR_BADPORT = -3; 210 static const int ERR_OVERFLOW = -4; 211 212 assert( s && addr && len && port ); 213 214 for( i = 0; (i < len) && s[i] && (':' != s[i]); ++i ) 215 addr[ i ] = s[ i ]; 216 if( i >= len ) 217 return ERR_OVERFLOW; 218 else 219 addr[i] = '\0'; 220 221 /* IP address is not followed by port */ 222 if( ':' != s[ i ] ) return ERR_NOPORT; 223 224 if( 1 != inet_aton( addr, &(saddr.sin_addr)) ) 225 return ERR_BADADDR; 226 227 ++i; 228 if( i >= len || !s[i] ) return ERR_NOPORT; 229 230 errno = 0; 231 iport = atoi( s + i ); 232 if( errno || (iport <= 0) || (iport > (int)USHRT_MAX) ) 233 return ERR_BADPORT; 234 235 *port = iport; 236 return 0; 237} 238 239 240/* __EOF__ */ 241 242