3 * API functions for name resolving
5 * @defgroup netdbapi NETDB API
10 * Redistribution and use in source and binary forms, with or without modification,
11 * are permitted provided that the following conditions are met:
13 * 1. Redistributions of source code must retain the above copyright notice,
14 * this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
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18 * 3. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32 * This file is part of the lwIP TCP/IP stack.
34 * Author: Simon Goldschmidt
38 #include "lwip/netdb.h"
40 #if LWIP_DNS && LWIP_SOCKET
44 #include "lwip/memp.h"
45 #include "lwip/ip_addr.h"
49 #include <string.h> /* memset */
50 #include <stdlib.h> /* atoi */
52 /** helper struct for gethostbyname_r to access the char* buffer */
53 struct gethostbyname_r_helper {
54 ip_addr_t *addr_list[2];
59 /** h_errno is exported in netdb.h for access by applications. */
60 #if LWIP_DNS_API_DECLARE_H_ERRNO
62 #endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
64 /** define "hostent" variables storage: 0 if we use a static (but unprotected)
65 * set of variables for lwip_gethostbyname, 1 if we use a local storage */
66 #ifndef LWIP_DNS_API_HOSTENT_STORAGE
67 #define LWIP_DNS_API_HOSTENT_STORAGE 0
70 /** define "hostent" variables storage */
71 #if LWIP_DNS_API_HOSTENT_STORAGE
72 #define HOSTENT_STORAGE
74 #define HOSTENT_STORAGE static
75 #endif /* LWIP_DNS_API_STATIC_HOSTENT */
78 * Returns an entry containing addresses of address family AF_INET
79 * for the host with name name.
80 * Due to dns_gethostbyname limitations, only one address is returned.
82 * @param name the hostname to resolve
83 * @return an entry containing addresses of address family AF_INET
84 * for the host with name name
87 lwip_gethostbyname(const char *name)
92 /* buffer variables for lwip_gethostbyname() */
93 HOSTENT_STORAGE struct hostent s_hostent;
94 HOSTENT_STORAGE char *s_aliases;
95 HOSTENT_STORAGE ip_addr_t s_hostent_addr;
96 HOSTENT_STORAGE ip_addr_t *s_phostent_addr[2];
97 HOSTENT_STORAGE char s_hostname[DNS_MAX_NAME_LENGTH + 1];
99 /* query host IP address */
100 err = netconn_gethostbyname(name, &addr);
102 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
103 h_errno = HOST_NOT_FOUND;
108 s_hostent_addr = addr;
109 s_phostent_addr[0] = &s_hostent_addr;
110 s_phostent_addr[1] = NULL;
111 strncpy(s_hostname, name, DNS_MAX_NAME_LENGTH);
112 s_hostname[DNS_MAX_NAME_LENGTH] = 0;
113 s_hostent.h_name = s_hostname;
115 s_hostent.h_aliases = &s_aliases;
116 s_hostent.h_addrtype = AF_INET;
117 s_hostent.h_length = sizeof(ip_addr_t);
118 s_hostent.h_addr_list = (char**)&s_phostent_addr;
122 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
123 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == %p\n", (void*)s_hostent.h_aliases));
124 /* h_aliases are always empty */
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", (void*)s_hostent.h_addr_list));
128 if (s_hostent.h_addr_list != NULL) {
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, ipaddr_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx])));
135 #endif /* DNS_DEBUG */
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);
142 #endif /* LWIP_DNS_API_HOSTENT_STORAGE */
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.
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
162 lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
163 size_t buflen, struct hostent **result, int *h_errnop)
166 struct gethostbyname_r_helper *h;
171 if (h_errnop == NULL) {
172 /* ensure h_errnop is never NULL */
173 h_errnop = &lh_errno;
176 if (result == NULL) {
177 /* not all arguments given */
181 /* first thing to do: set *result to nothing */
183 if ((name == NULL) || (ret == NULL) || (buf == NULL)) {
184 /* not all arguments given */
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 */
196 h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
197 hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
199 /* query host IP address */
200 err = netconn_gethostbyname(name, &h->addr);
202 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
203 *h_errnop = HOST_NOT_FOUND;
207 /* copy the hostname into buf */
208 MEMCPY(hostname, name, namelen);
209 hostname[namelen] = 0;
212 h->addr_list[0] = &h->addr;
213 h->addr_list[1] = NULL;
215 ret->h_name = hostname;
216 ret->h_aliases = &h->aliases;
217 ret->h_addrtype = AF_INET;
218 ret->h_length = sizeof(ip_addr_t);
219 ret->h_addr_list = (char**)&h->addr_list;
221 /* set result != NULL */
229 * Frees one or more addrinfo structures returned by getaddrinfo(), along with
230 * any additional storage associated with those structures. If the ai_next field
231 * of the structure is not null, the entire list of structures is freed.
233 * @param ai struct addrinfo to free
236 lwip_freeaddrinfo(struct addrinfo *ai)
238 struct addrinfo *next;
242 memp_free(MEMP_NETDB, ai);
248 * Translates the name of a service location (for example, a host name) and/or
249 * a service name and returns a set of socket addresses and associated
250 * information to be used in creating a socket with which to address the
252 * Memory for the result is allocated internally and must be freed by calling
253 * lwip_freeaddrinfo()!
255 * Due to a limitation in dns_gethostbyname, only the first address of a
257 * Also, service names are not supported (only port numbers)!
259 * @param nodename descriptive name or address string of the host
260 * (may be NULL -> local address)
261 * @param servname port number as string of NULL
262 * @param hints structure containing input values that set socktype and protocol
263 * @param res pointer to a pointer where to store the result (set to NULL on failure)
264 * @return 0 on success, non-zero on failure
266 * @todo: implement AI_V4MAPPED, AI_ADDRCONFIG
269 lwip_getaddrinfo(const char *nodename, const char *servname,
270 const struct addrinfo *hints, struct addrinfo **res)
275 struct sockaddr_storage *sa = NULL;
285 if ((nodename == NULL) && (servname == NULL)) {
290 ai_family = hints->ai_family;
291 if ((ai_family != AF_UNSPEC)
293 && (ai_family != AF_INET)
294 #endif /* LWIP_IPV4 */
296 && (ai_family != AF_INET6)
297 #endif /* LWIP_IPV6 */
302 ai_family = AF_UNSPEC;
305 if (servname != NULL) {
306 /* service name specified: convert to port number
307 * @todo?: currently, only ASCII integers (port numbers) are supported (AI_NUMERICSERV)! */
308 port_nr = atoi(servname);
309 if ((port_nr <= 0) || (port_nr > 0xffff)) {
314 if (nodename != NULL) {
315 /* service location specified, try to resolve */
316 if ((hints != NULL) && (hints->ai_flags & AI_NUMERICHOST)) {
317 /* no DNS lookup, just parse for an address string */
318 if (!ipaddr_aton(nodename, &addr)) {
321 #if LWIP_IPV4 && LWIP_IPV6
322 if ((IP_IS_V6_VAL(addr) && ai_family == AF_INET) ||
323 (IP_IS_V4_VAL(addr) && ai_family == AF_INET6)) {
326 #endif /* LWIP_IPV4 && LWIP_IPV6 */
328 #if LWIP_IPV4 && LWIP_IPV6
329 /* AF_UNSPEC: prefer IPv4 */
330 u8_t type = NETCONN_DNS_IPV4_IPV6;
331 if (ai_family == AF_INET) {
332 type = NETCONN_DNS_IPV4;
333 } else if (ai_family == AF_INET6) {
334 type = NETCONN_DNS_IPV6;
336 #endif /* LWIP_IPV4 && LWIP_IPV6 */
337 err = netconn_gethostbyname_addrtype(nodename, &addr, type);
343 /* service location specified, use loopback address */
344 if ((hints != NULL) && (hints->ai_flags & AI_PASSIVE)) {
345 ip_addr_set_any(ai_family == AF_INET6, &addr);
347 ip_addr_set_loopback(ai_family == AF_INET6, &addr);
351 total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_storage);
352 if (nodename != NULL) {
353 namelen = strlen(nodename);
354 if (namelen > DNS_MAX_NAME_LENGTH) {
355 /* invalid name length */
358 LWIP_ASSERT("namelen is too long", total_size + namelen + 1 > total_size);
359 total_size += namelen + 1;
361 /* If this fails, please report to lwip-devel! :-) */
362 LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
363 total_size <= NETDB_ELEM_SIZE);
364 ai = (struct addrinfo *)memp_malloc(MEMP_NETDB);
368 memset(ai, 0, total_size);
369 /* cast through void* to get rid of alignment warnings */
370 sa = (struct sockaddr_storage *)(void*)((u8_t*)ai + sizeof(struct addrinfo));
371 if (IP_IS_V6_VAL(addr)) {
373 struct sockaddr_in6 *sa6 = (struct sockaddr_in6*)sa;
374 /* set up sockaddr */
375 inet6_addr_from_ip6addr(&sa6->sin6_addr, ip_2_ip6(&addr));
376 sa6->sin6_family = AF_INET6;
377 sa6->sin6_len = sizeof(struct sockaddr_in6);
378 sa6->sin6_port = lwip_htons((u16_t)port_nr);
379 ai->ai_family = AF_INET6;
380 #endif /* LWIP_IPV6 */
383 struct sockaddr_in *sa4 = (struct sockaddr_in*)sa;
384 /* set up sockaddr */
385 inet_addr_from_ip4addr(&sa4->sin_addr, ip_2_ip4(&addr));
386 sa4->sin_family = AF_INET;
387 sa4->sin_len = sizeof(struct sockaddr_in);
388 sa4->sin_port = lwip_htons((u16_t)port_nr);
389 ai->ai_family = AF_INET;
390 #endif /* LWIP_IPV4 */
393 /* set up addrinfo */
395 /* copy socktype & protocol from hints if specified */
396 ai->ai_socktype = hints->ai_socktype;
397 ai->ai_protocol = hints->ai_protocol;
399 if (nodename != NULL) {
400 /* copy nodename to canonname if specified */
401 ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_storage));
402 MEMCPY(ai->ai_canonname, nodename, namelen);
403 ai->ai_canonname[namelen] = 0;
405 ai->ai_addrlen = sizeof(struct sockaddr_storage);
406 ai->ai_addr = (struct sockaddr*)sa;
413 #endif /* LWIP_DNS && LWIP_SOCKET */