1 2 /* Copyright 1998 by the Massachusetts Institute of Technology. 3 * 4 * Permission to use, copy, modify, and distribute this 5 * software and its documentation for any purpose and without 6 * fee is hereby granted, provided that the above copyright 7 * notice appear in all copies and that both that copyright 8 * notice and this permission notice appear in supporting 9 * documentation, and that the name of M.I.T. not be used in 10 * advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. 12 * M.I.T. makes no representations about the suitability of 13 * this software for any purpose. It is provided "as is" 14 * without express or implied warranty. 15 */ 16 #include "ares_setup.h" 17 18 #ifdef HAVE_SYS_SOCKET_H 19 # include <sys/socket.h> 20 #endif 21 #ifdef HAVE_NETINET_IN_H 22 # include <netinet/in.h> 23 #endif 24 #ifdef HAVE_NETDB_H 25 # include <netdb.h> 26 #endif 27 #ifdef HAVE_ARPA_INET_H 28 # include <arpa/inet.h> 29 #endif 30 #ifdef HAVE_ARPA_NAMESER_H 31 # include <arpa/nameser.h> 32 #else 33 # include "nameser.h" 34 #endif 35 #ifdef HAVE_ARPA_NAMESER_COMPAT_H 36 # include <arpa/nameser_compat.h> 37 #endif 38 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 43 #include "ares.h" 44 #include "inet_net_pton.h" 45 #include "ares_platform.h" 46 #include "ares_private.h" 47 48 #ifdef WATT32 49 #undef WIN32 50 #endif 51 52 struct addr_query { 53 /* Arguments passed to ares_gethostbyaddr() */ 54 ares_channel channel; 55 struct ares_addr addr; 56 ares_host_callback callback; 57 void *arg; 58 59 const char *remaining_lookups; 60 int timeouts; 61 }; 62 63 static void next_lookup(struct addr_query *aquery); 64 static void addr_callback(void *arg, int status, int timeouts, 65 unsigned char *abuf, int alen); 66 static void end_aquery(struct addr_query *aquery, int status, 67 struct hostent *host); 68 static int file_lookup(struct ares_addr *addr, struct hostent **host); 69 static void ptr_rr_name(char *name, const struct ares_addr *addr); 70 71 void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen, 72 int family, ares_host_callback callback, void *arg) 73 { 74 struct addr_query *aquery; 75 76 if (family != AF_INET && family != AF_INET6) 77 { 78 callback(arg, ARES_ENOTIMP, 0, NULL); 79 return; 80 } 81 82 if ((family == AF_INET && addrlen != sizeof(aquery->addr.addrV4)) || 83 (family == AF_INET6 && addrlen != sizeof(aquery->addr.addrV6))) 84 { 85 callback(arg, ARES_ENOTIMP, 0, NULL); 86 return; 87 } 88 89 aquery = malloc(sizeof(struct addr_query)); 90 if (!aquery) 91 { 92 callback(arg, ARES_ENOMEM, 0, NULL); 93 return; 94 } 95 aquery->channel = channel; 96 if (family == AF_INET) 97 memcpy(&aquery->addr.addrV4, addr, sizeof(aquery->addr.addrV4)); 98 else 99 memcpy(&aquery->addr.addrV6, addr, sizeof(aquery->addr.addrV6)); 100 aquery->addr.family = family; 101 aquery->callback = callback; 102 aquery->arg = arg; 103 aquery->remaining_lookups = channel->lookups; 104 aquery->timeouts = 0; 105 106 next_lookup(aquery); 107 } 108 109 static void next_lookup(struct addr_query *aquery) 110 { 111 const char *p; 112 char name[128]; 113 int status; 114 struct hostent *host; 115 116 for (p = aquery->remaining_lookups; *p; p++) 117 { 118 switch (*p) 119 { 120 case 'b': 121 ptr_rr_name(name, &aquery->addr); 122 aquery->remaining_lookups = p + 1; 123 ares_query(aquery->channel, name, C_IN, T_PTR, addr_callback, 124 aquery); 125 return; 126 case 'f': 127 status = file_lookup(&aquery->addr, &host); 128 129 /* this status check below previously checked for !ARES_ENOTFOUND, 130 but we should not assume that this single error code is the one 131 that can occur, as that is in fact no longer the case */ 132 if (status == ARES_SUCCESS) 133 { 134 end_aquery(aquery, status, host); 135 return; 136 } 137 break; 138 } 139 } 140 end_aquery(aquery, ARES_ENOTFOUND, NULL); 141 } 142 143 static void addr_callback(void *arg, int status, int timeouts, 144 unsigned char *abuf, int alen) 145 { 146 struct addr_query *aquery = (struct addr_query *) arg; 147 struct hostent *host; 148 size_t addrlen; 149 150 aquery->timeouts += timeouts; 151 if (status == ARES_SUCCESS) 152 { 153 if (aquery->addr.family == AF_INET) 154 { 155 addrlen = sizeof(aquery->addr.addrV4); 156 status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV4, 157 (int)addrlen, AF_INET, &host); 158 } 159 else 160 { 161 addrlen = sizeof(aquery->addr.addrV6); 162 status = ares_parse_ptr_reply(abuf, alen, &aquery->addr.addrV6, 163 (int)addrlen, AF_INET6, &host); 164 } 165 end_aquery(aquery, status, host); 166 } 167 else if (status == ARES_EDESTRUCTION) 168 end_aquery(aquery, status, NULL); 169 else 170 next_lookup(aquery); 171 } 172 173 static void end_aquery(struct addr_query *aquery, int status, 174 struct hostent *host) 175 { 176 aquery->callback(aquery->arg, status, aquery->timeouts, host); 177 if (host) 178 ares_free_hostent(host); 179 free(aquery); 180 } 181 182 static int file_lookup(struct ares_addr *addr, struct hostent **host) 183 { 184 FILE *fp; 185 int status; 186 int error; 187 188 #ifdef WIN32 189 char PATH_HOSTS[MAX_PATH]; 190 win_platform platform; 191 192 PATH_HOSTS[0] = '\0'; 193 194 platform = ares__getplatform(); 195 196 if (platform == WIN_NT) { 197 char tmp[MAX_PATH]; 198 HKEY hkeyHosts; 199 200 if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0, KEY_READ, 201 &hkeyHosts) == ERROR_SUCCESS) 202 { 203 DWORD dwLength = MAX_PATH; 204 RegQueryValueEx(hkeyHosts, DATABASEPATH, NULL, NULL, (LPBYTE)tmp, 205 &dwLength); 206 ExpandEnvironmentStrings(tmp, PATH_HOSTS, MAX_PATH); 207 RegCloseKey(hkeyHosts); 208 } 209 } 210 else if (platform == WIN_9X) 211 GetWindowsDirectory(PATH_HOSTS, MAX_PATH); 212 else 213 return ARES_ENOTFOUND; 214 215 strcat(PATH_HOSTS, WIN_PATH_HOSTS); 216 217 #elif defined(WATT32) 218 extern const char *_w32_GetHostsFile (void); 219 const char *PATH_HOSTS = _w32_GetHostsFile(); 220 221 if (!PATH_HOSTS) 222 return ARES_ENOTFOUND; 223 #endif 224 225 fp = fopen(PATH_HOSTS, "r"); 226 if (!fp) 227 { 228 error = ERRNO; 229 switch(error) 230 { 231 case ENOENT: 232 case ESRCH: 233 return ARES_ENOTFOUND; 234 default: 235 DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n", 236 error, strerror(error))); 237 DEBUGF(fprintf(stderr, "Error opening file: %s\n", 238 PATH_HOSTS)); 239 *host = NULL; 240 return ARES_EFILE; 241 } 242 } 243 while ((status = ares__get_hostent(fp, addr->family, host)) == ARES_SUCCESS) 244 { 245 if (addr->family != (*host)->h_addrtype) 246 { 247 ares_free_hostent(*host); 248 continue; 249 } 250 if (addr->family == AF_INET) 251 { 252 if (memcmp((*host)->h_addr, &addr->addrV4, 253 sizeof(addr->addrV4)) == 0) 254 break; 255 } 256 else if (addr->family == AF_INET6) 257 { 258 if (memcmp((*host)->h_addr, &addr->addrV6, 259 sizeof(addr->addrV6)) == 0) 260 break; 261 } 262 ares_free_hostent(*host); 263 } 264 fclose(fp); 265 if (status == ARES_EOF) 266 status = ARES_ENOTFOUND; 267 if (status != ARES_SUCCESS) 268 *host = NULL; 269 return status; 270 } 271 272 static void ptr_rr_name(char *name, const struct ares_addr *addr) 273 { 274 if (addr->family == AF_INET) 275 { 276 unsigned long laddr = ntohl(addr->addrV4.s_addr); 277 unsigned long a1 = (laddr >> 24UL) & 0xFFUL; 278 unsigned long a2 = (laddr >> 16UL) & 0xFFUL; 279 unsigned long a3 = (laddr >> 8UL) & 0xFFUL; 280 unsigned long a4 = laddr & 0xFFUL; 281 sprintf(name, "%lu.%lu.%lu.%lu.in-addr.arpa", a4, a3, a2, a1); 282 } 283 else 284 { 285 unsigned char *bytes = (unsigned char *)&addr->addrV6; 286 /* There are too many arguments to do this in one line using 287 * minimally C89-compliant compilers */ 288 sprintf(name, 289 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.", 290 bytes[15]&0xf, bytes[15] >> 4, bytes[14]&0xf, bytes[14] >> 4, 291 bytes[13]&0xf, bytes[13] >> 4, bytes[12]&0xf, bytes[12] >> 4, 292 bytes[11]&0xf, bytes[11] >> 4, bytes[10]&0xf, bytes[10] >> 4, 293 bytes[9]&0xf, bytes[9] >> 4, bytes[8]&0xf, bytes[8] >> 4); 294 sprintf(name+strlen(name), 295 "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.arpa", 296 bytes[7]&0xf, bytes[7] >> 4, bytes[6]&0xf, bytes[6] >> 4, 297 bytes[5]&0xf, bytes[5] >> 4, bytes[4]&0xf, bytes[4] >> 4, 298 bytes[3]&0xf, bytes[3] >> 4, bytes[2]&0xf, bytes[2] >> 4, 299 bytes[1]&0xf, bytes[1] >> 4, bytes[0]&0xf, bytes[0] >> 4); 300 } 301 } 302