1 /** 2 * @file 3 * API functions for name resolving 4 * 5 */ 6 7 /* 8 * Redistribution and use in source and binary forms, with or without modification, 9 * are permitted provided that the following conditions are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright notice, 12 * this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright notice, 14 * this list of conditions and the following disclaimer in the documentation 15 * and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 22 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 24 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 27 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 28 * OF SUCH DAMAGE. 29 * 30 * This file is part of the lwIP TCP/IP stack. 31 * 32 * Author: Simon Goldschmidt 33 * 34 */ 35 36 #include "lwip/netdb.h" 37 38 #if LWIP_DNS && LWIP_SOCKET 39 40 #include "lwip/err.h" 41 #include "lwip/mem.h" 42 #include "lwip/memp.h" 43 #include "lwip/ip_addr.h" 44 #include "lwip/api.h" 45 #include "lwip/dns.h" 46 47 #include <string.h> 48 #include <stdlib.h> 49 50 /** helper struct for gethostbyname_r to access the char* buffer */ 51 struct gethostbyname_r_helper { 52 ip_addr_t *addrs; 53 ip_addr_t addr; 54 char *aliases; 55 }; 56 57 /** h_errno is exported in netdb.h for access by applications. */ 58 #if LWIP_DNS_API_DECLARE_H_ERRNO 59 int h_errno; 60 #endif /* LWIP_DNS_API_DECLARE_H_ERRNO */ 61 62 /** define "hostent" variables storage: 0 if we use a static (but unprotected) 63 * set of variables for lwip_gethostbyname, 1 if we use a local storage */ 64 #ifndef LWIP_DNS_API_HOSTENT_STORAGE 65 #define LWIP_DNS_API_HOSTENT_STORAGE 0 66 #endif 67 68 /** define "hostent" variables storage */ 69 #if LWIP_DNS_API_HOSTENT_STORAGE 70 #define HOSTENT_STORAGE 71 #else 72 #define HOSTENT_STORAGE static 73 #endif /* LWIP_DNS_API_STATIC_HOSTENT */ 74 75 /** 76 * Returns an entry containing addresses of address family AF_INET 77 * for the host with name name. 78 * Due to dns_gethostbyname limitations, only one address is returned. 79 * 80 * @param name the hostname to resolve 81 * @return an entry containing addresses of address family AF_INET 82 * for the host with name name 83 */ 84 struct hostent* 85 lwip_gethostbyname(const char *name) 86 { 87 err_t err; 88 ip_addr_t addr; 89 90 /* buffer variables for lwip_gethostbyname() */ 91 HOSTENT_STORAGE struct hostent s_hostent; 92 HOSTENT_STORAGE char *s_aliases; 93 HOSTENT_STORAGE ip_addr_t s_hostent_addr; 94 HOSTENT_STORAGE ip_addr_t *s_phostent_addr[2]; 95 96 /* query host IP address */ 97 err = netconn_gethostbyname(name, &addr); 98 if (err != ERR_OK) { 99 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err)); 100 h_errno = HOST_NOT_FOUND; 101 return NULL; 102 } 103 104 /* fill hostent */ 105 s_hostent_addr = addr; 106 s_phostent_addr[0] = &s_hostent_addr; 107 s_phostent_addr[1] = NULL; 108 s_hostent.h_name = (char*)name; 109 s_hostent.h_aliases = &s_aliases; 110 s_hostent.h_addrtype = AF_INET; 111 s_hostent.h_length = sizeof(ip_addr_t); 112 s_hostent.h_addr_list = (char**)&s_phostent_addr; 113 114 #if DNS_DEBUG 115 /* dump hostent */ 116 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name)); 117 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == %p\n", s_hostent.h_aliases)); 118 if (s_hostent.h_aliases != NULL) { 119 u8_t idx; 120 for ( idx=0; s_hostent.h_aliases[idx]; idx++) { 121 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %p\n", idx, s_hostent.h_aliases[idx])); 122 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %s\n", idx, s_hostent.h_aliases[idx])); 123 } 124 } 125 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %d\n", s_hostent.h_addrtype)); 126 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %d\n", s_hostent.h_length)); 127 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == %p\n", s_hostent.h_addr_list)); 128 if (s_hostent.h_addr_list != NULL) { 129 u8_t idx; 130 for ( idx=0; s_hostent.h_addr_list[idx]; idx++) { 131 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == %p\n", idx, s_hostent.h_addr_list[idx])); 132 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, ip_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx]))); 133 } 134 } 135 #endif /* DNS_DEBUG */ 136 137 #if LWIP_DNS_API_HOSTENT_STORAGE 138 /* this function should return the "per-thread" hostent after copy from s_hostent */ 139 return sys_thread_hostent(&s_hostent); 140 #else 141 return &s_hostent; 142 #endif /* LWIP_DNS_API_HOSTENT_STORAGE */ 143 } 144 145 /** 146 * Thread-safe variant of lwip_gethostbyname: instead of using a static 147 * buffer, this function takes buffer and errno pointers as arguments 148 * and uses these for the result. 149 * 150 * @param name the hostname to resolve 151 * @param ret pre-allocated struct where to store the result 152 * @param buf pre-allocated buffer where to store additional data 153 * @param buflen the size of buf 154 * @param result pointer to a hostent pointer that is set to ret on success 155 * and set to zero on error 156 * @param h_errnop pointer to an int where to store errors (instead of modifying 157 * the global h_errno) 158 * @return 0 on success, non-zero on error, additional error information 159 * is stored in *h_errnop instead of h_errno to be thread-safe 160 */ 161 int 162 lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf, 163 size_t buflen, struct hostent **result, int *h_errnop) 164 { 165 err_t err; 166 struct gethostbyname_r_helper *h; 167 char *hostname; 168 size_t namelen; 169 int lh_errno; 170 171 if (h_errnop == NULL) { 172 /* ensure h_errnop is never NULL */ 173 h_errnop = &lh_errno; 174 } 175 176 if (result == NULL) { 177 /* not all arguments given */ 178 *h_errnop = EINVAL; 179 return -1; 180 } 181 /* first thing to do: set *result to nothing */ 182 *result = NULL; 183 if ((name == NULL) || (ret == NULL) || (buf == 0)) { 184 /* not all arguments given */ 185 *h_errnop = EINVAL; 186 return -1; 187 } 188 189 namelen = strlen(name); 190 if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) { 191 /* buf can't hold the data needed + a copy of name */ 192 *h_errnop = ERANGE; 193 return -1; 194 } 195 196 h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf); 197 hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper); 198 199 /* query host IP address */ 200 err = netconn_gethostbyname(name, &(h->addr)); 201 if (err != ERR_OK) { 202 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err)); 203 *h_errnop = ENSRNOTFOUND; 204 return -1; 205 } 206 207 /* copy the hostname into buf */ 208 MEMCPY(hostname, name, namelen); 209 hostname[namelen] = 0; 210 211 /* fill hostent */ 212 h->addrs = &(h->addr); 213 h->aliases = NULL; 214 ret->h_name = (char*)hostname; 215 ret->h_aliases = &(h->aliases); 216 ret->h_addrtype = AF_INET; 217 ret->h_length = sizeof(ip_addr_t); 218 ret->h_addr_list = (char**)&(h->addrs); 219 220 /* set result != NULL */ 221 *result = ret; 222 223 /* return success */ 224 return 0; 225 } 226 227 /** 228 * Frees one or more addrinfo structures returned by getaddrinfo(), along with 229 * any additional storage associated with those structures. If the ai_next field 230 * of the structure is not null, the entire list of structures is freed. 231 * 232 * @param ai struct addrinfo to free 233 */ 234 void 235 lwip_freeaddrinfo(struct addrinfo *ai) 236 { 237 struct addrinfo *next; 238 239 while (ai != NULL) { 240 next = ai->ai_next; 241 memp_free(MEMP_NETDB, ai); 242 ai = next; 243 } 244 } 245 246 /** 247 * Translates the name of a service location (for example, a host name) and/or 248 * a service name and returns a set of socket addresses and associated 249 * information to be used in creating a socket with which to address the 250 * specified service. 251 * Memory for the result is allocated internally and must be freed by calling 252 * lwip_freeaddrinfo()! 253 * 254 * Due to a limitation in dns_gethostbyname, only the first address of a 255 * host is returned. 256 * Also, service names are not supported (only port numbers)! 257 * 258 * @param nodename descriptive name or address string of the host 259 * (may be NULL -> local address) 260 * @param servname port number as string of NULL 261 * @param hints structure containing input values that set socktype and protocol 262 * @param res pointer to a pointer where to store the result (set to NULL on failure) 263 * @return 0 on success, non-zero on failure 264 */ 265 int 266 lwip_getaddrinfo(const char *nodename, const char *servname, 267 const struct addrinfo *hints, struct addrinfo **res) 268 { 269 err_t err; 270 ip_addr_t addr; 271 struct addrinfo *ai; 272 struct sockaddr_in *sa = NULL; 273 int port_nr = 0; 274 size_t total_size; 275 size_t namelen = 0; 276 277 if (res == NULL) { 278 return EAI_FAIL; 279 } 280 *res = NULL; 281 if ((nodename == NULL) && (servname == NULL)) { 282 return EAI_NONAME; 283 } 284 285 if (servname != NULL) { 286 /* service name specified: convert to port number 287 * @todo?: currently, only ASCII integers (port numbers) are supported! */ 288 port_nr = atoi(servname); 289 if ((port_nr <= 0) || (port_nr > 0xffff)) { 290 return EAI_SERVICE; 291 } 292 } 293 294 if (nodename != NULL) { 295 /* service location specified, try to resolve */ 296 err = netconn_gethostbyname(nodename, &addr); 297 if (err != ERR_OK) { 298 return EAI_FAIL; 299 } 300 } else { 301 /* service location specified, use loopback address */ 302 ip_addr_set_loopback(&addr); 303 } 304 305 total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_in); 306 if (nodename != NULL) { 307 namelen = strlen(nodename); 308 LWIP_ASSERT("namelen is too long", (namelen + 1) <= (mem_size_t)-1); 309 total_size += namelen + 1; 310 } 311 /* If this fails, please report to lwip-devel! :-) */ 312 LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!", 313 total_size <= NETDB_ELEM_SIZE); 314 ai = (struct addrinfo *)memp_malloc(MEMP_NETDB); 315 if (ai == NULL) { 316 goto memerr; 317 } 318 memset(ai, 0, total_size); 319 sa = (struct sockaddr_in*)((u8_t*)ai + sizeof(struct addrinfo)); 320 /* set up sockaddr */ 321 inet_addr_from_ipaddr(&sa->sin_addr, &addr); 322 sa->sin_family = AF_INET; 323 sa->sin_len = sizeof(struct sockaddr_in); 324 sa->sin_port = htons((u16_t)port_nr); 325 326 /* set up addrinfo */ 327 ai->ai_family = AF_INET; 328 if (hints != NULL) { 329 /* copy socktype & protocol from hints if specified */ 330 ai->ai_socktype = hints->ai_socktype; 331 ai->ai_protocol = hints->ai_protocol; 332 } 333 if (nodename != NULL) { 334 /* copy nodename to canonname if specified */ 335 ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_in)); 336 MEMCPY(ai->ai_canonname, nodename, namelen); 337 ai->ai_canonname[namelen] = 0; 338 } 339 ai->ai_addrlen = sizeof(struct sockaddr_in); 340 ai->ai_addr = (struct sockaddr*)sa; 341 342 *res = ai; 343 344 return 0; 345 memerr: 346 if (ai != NULL) { 347 memp_free(MEMP_NETDB, ai); 348 } 349 return EAI_MEMORY; 350 } 351 352 #endif /* LWIP_DNS && LWIP_SOCKET */ 353
