3 * API functions for name resolving
8 * Redistribution and use in source and binary forms, with or without modification,
9 * are permitted provided that the following conditions are met:
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.
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
30 * This file is part of the lwIP TCP/IP stack.
32 * Author: Simon Goldschmidt
36 #include "lwip/netdb.h"
38 #if LWIP_DNS && LWIP_SOCKET
42 #include "lwip/memp.h"
43 #include "lwip/ip_addr.h"
50 /** helper struct for gethostbyname_r to access the char* buffer */
51 struct gethostbyname_r_helper {
57 /** h_errno is exported in netdb.h for access by applications. */
58 #if LWIP_DNS_API_DECLARE_H_ERRNO
60 #endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
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
68 /** define "hostent" variables storage */
69 #if LWIP_DNS_API_HOSTENT_STORAGE
70 #define HOSTENT_STORAGE
72 #define HOSTENT_STORAGE static
73 #endif /* LWIP_DNS_API_STATIC_HOSTENT */
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.
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
85 lwip_gethostbyname(const char *name)
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] = { 0 };
96 /* query host IP address */
97 err = netconn_gethostbyname(name, &addr);
99 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
100 h_errno = HOST_NOT_FOUND;
105 s_hostent_addr = addr;
106 s_phostent_addr[0] = &s_hostent_addr;
107 s_hostent.h_name = (char*)name;
108 s_hostent.h_aliases = &s_aliases;
109 s_hostent.h_addrtype = AF_INET;
110 s_hostent.h_length = sizeof(ip_addr_t);
111 s_hostent.h_addr_list = (char**)&s_phostent_addr;
115 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
116 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == %p\n", s_hostent.h_aliases));
117 if (s_hostent.h_aliases != NULL) {
119 for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
120 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %p\n", idx, s_hostent.h_aliases[idx]));
121 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %s\n", idx, s_hostent.h_aliases[idx]));
124 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %d\n", s_hostent.h_addrtype));
125 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %d\n", s_hostent.h_length));
126 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == %p\n", s_hostent.h_addr_list));
127 if (s_hostent.h_addr_list != NULL) {
129 for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
130 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == %p\n", idx, s_hostent.h_addr_list[idx]));
131 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, ip_ntoa((ip_addr_t*)s_hostent.h_addr_list[idx])));
134 #endif /* DNS_DEBUG */
136 #if LWIP_DNS_API_HOSTENT_STORAGE
137 /* this function should return the "per-thread" hostent after copy from s_hostent */
138 return sys_thread_hostent(&s_hostent);
141 #endif /* LWIP_DNS_API_HOSTENT_STORAGE */
145 * Thread-safe variant of lwip_gethostbyname: instead of using a static
146 * buffer, this function takes buffer and errno pointers as arguments
147 * and uses these for the result.
149 * @param name the hostname to resolve
150 * @param ret pre-allocated struct where to store the result
151 * @param buf pre-allocated buffer where to store additional data
152 * @param buflen the size of buf
153 * @param result pointer to a hostent pointer that is set to ret on success
154 * and set to zero on error
155 * @param h_errnop pointer to an int where to store errors (instead of modifying
156 * the global h_errno)
157 * @return 0 on success, non-zero on error, additional error information
158 * is stored in *h_errnop instead of h_errno to be thread-safe
161 lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
162 size_t buflen, struct hostent **result, int *h_errnop)
165 struct gethostbyname_r_helper *h;
170 if (h_errnop == NULL) {
171 /* ensure h_errnop is never NULL */
172 h_errnop = &lh_errno;
175 if (result == NULL) {
176 /* not all arguments given */
180 /* first thing to do: set *result to nothing */
182 if ((name == NULL) || (ret == NULL) || (buf == 0)) {
183 /* not all arguments given */
188 namelen = strlen(name);
189 if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
190 /* buf can't hold the data needed + a copy of name */
195 h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
196 hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
198 /* query host IP address */
199 err = netconn_gethostbyname(name, &(h->addr));
201 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
202 *h_errnop = ENSRNOTFOUND;
206 /* copy the hostname into buf */
207 MEMCPY(hostname, name, namelen);
208 hostname[namelen] = 0;
211 h->addrs = &(h->addr);
213 ret->h_name = (char*)hostname;
214 ret->h_aliases = &(h->aliases);
215 ret->h_addrtype = AF_INET;
216 ret->h_length = sizeof(ip_addr_t);
217 ret->h_addr_list = (char**)&(h->addrs);
219 /* set result != NULL */
227 * Frees one or more addrinfo structures returned by getaddrinfo(), along with
228 * any additional storage associated with those structures. If the ai_next field
229 * of the structure is not null, the entire list of structures is freed.
231 * @param ai struct addrinfo to free
234 lwip_freeaddrinfo(struct addrinfo *ai)
236 struct addrinfo *next;
240 memp_free(MEMP_NETDB, ai);
246 * Translates the name of a service location (for example, a host name) and/or
247 * a service name and returns a set of socket addresses and associated
248 * information to be used in creating a socket with which to address the
250 * Memory for the result is allocated internally and must be freed by calling
251 * lwip_freeaddrinfo()!
253 * Due to a limitation in dns_gethostbyname, only the first address of a
255 * Also, service names are not supported (only port numbers)!
257 * @param nodename descriptive name or address string of the host
258 * (may be NULL -> local address)
259 * @param servname port number as string of NULL
260 * @param hints structure containing input values that set socktype and protocol
261 * @param res pointer to a pointer where to store the result (set to NULL on failure)
262 * @return 0 on success, non-zero on failure
265 lwip_getaddrinfo(const char *nodename, const char *servname,
266 const struct addrinfo *hints, struct addrinfo **res)
271 struct sockaddr_in *sa = NULL;
280 if ((nodename == NULL) && (servname == NULL)) {
284 if (servname != NULL) {
285 /* service name specified: convert to port number
286 * @todo?: currently, only ASCII integers (port numbers) are supported! */
287 port_nr = atoi(servname);
288 if ((port_nr <= 0) || (port_nr > 0xffff)) {
293 if (nodename != NULL) {
294 /* service location specified, try to resolve */
295 err = netconn_gethostbyname(nodename, &addr);
300 /* service location specified, use loopback address */
301 ip_addr_set_loopback(&addr);
304 total_size = sizeof(struct addrinfo) + sizeof(struct sockaddr_in);
305 if (nodename != NULL) {
306 namelen = strlen(nodename);
307 LWIP_ASSERT("namelen is too long", (namelen + 1) <= (mem_size_t)-1);
308 total_size += namelen + 1;
310 /* If this fails, please report to lwip-devel! :-) */
311 LWIP_ASSERT("total_size <= NETDB_ELEM_SIZE: please report this!",
312 total_size <= NETDB_ELEM_SIZE);
313 ai = (struct addrinfo *)memp_malloc(MEMP_NETDB);
317 memset(ai, 0, total_size);
318 sa = (struct sockaddr_in*)((u8_t*)ai + sizeof(struct addrinfo));
319 /* set up sockaddr */
320 inet_addr_from_ipaddr(&sa->sin_addr, &addr);
321 sa->sin_family = AF_INET;
322 sa->sin_len = sizeof(struct sockaddr_in);
323 sa->sin_port = htons((u16_t)port_nr);
325 /* set up addrinfo */
326 ai->ai_family = AF_INET;
328 /* copy socktype & protocol from hints if specified */
329 ai->ai_socktype = hints->ai_socktype;
330 ai->ai_protocol = hints->ai_protocol;
332 if (nodename != NULL) {
333 /* copy nodename to canonname if specified */
334 ai->ai_canonname = ((char*)ai + sizeof(struct addrinfo) + sizeof(struct sockaddr_in));
335 MEMCPY(ai->ai_canonname, nodename, namelen);
336 ai->ai_canonname[namelen] = 0;
338 ai->ai_addrlen = sizeof(struct sockaddr_in);
339 ai->ai_addr = (struct sockaddr*)sa;
346 memp_free(MEMP_NETDB, ai);
351 #endif /* LWIP_DNS && LWIP_SOCKET */