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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/ip_addr.h"
43#include "lwip/api.h"
44
45/** helper struct for gethostbyname_r to access the char* buffer */
46struct gethostbyname_r_helper {
47 struct ip_addr *addrs;
48 struct ip_addr addr;
49 char *aliases;
50};
51
52/** h_errno is exported in netdb.h for access by applications. */
53#if LWIP_DNS_API_DECLARE_H_ERRNO
54int h_errno;
55#endif /* LWIP_DNS_API_DECLARE_H_ERRNO */
56
57/** define "hostent" variables storage: 0 if we use a static (but unprotected)
58 * set of variables for lwip_gethostbyname, 1 if we use a local storage */
59#ifndef LWIP_DNS_API_HOSTENT_STORAGE
60#define LWIP_DNS_API_HOSTENT_STORAGE 0
61#endif
62
63/** define "hostent" variables storage */
64#if LWIP_DNS_API_HOSTENT_STORAGE
65#define HOSTENT_STORAGE
66#else
67#define HOSTENT_STORAGE static
68#endif /* LWIP_DNS_API_STATIC_HOSTENT */
69
70/**
71 * Returns an entry containing addresses of address family AF_INET
72 * for the host with name name.
73 * Due to dns_gethostbyname limitations, only one address is returned.
74 *
75 * @param name the hostname to resolve
76 * @return an entry containing addresses of address family AF_INET
77 * for the host with name name
78 */
79struct hostent*
80lwip_gethostbyname(const char *name)
81{
82 err_t err;
83 struct ip_addr addr;
84
85 /* buffer variables for lwip_gethostbyname() */
86 HOSTENT_STORAGE struct hostent s_hostent;
87 HOSTENT_STORAGE char *s_aliases;
88 HOSTENT_STORAGE struct ip_addr s_hostent_addr;
89 HOSTENT_STORAGE struct ip_addr *s_phostent_addr;
90
91 /* query host IP address */
92 err = netconn_gethostbyname(name, &addr);
93 if (err != ERR_OK) {
94 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
95 h_errno = HOST_NOT_FOUND;
96 return NULL;
97 }
98
99 /* fill hostent */
100 s_hostent_addr = addr;
101 s_phostent_addr = &s_hostent_addr;
102 s_hostent.h_name = (char*)name;
103 s_hostent.h_aliases = &s_aliases;
104 s_hostent.h_addrtype = AF_INET;
105 s_hostent.h_length = sizeof(struct ip_addr);
106 s_hostent.h_addr_list = (char**)&s_phostent_addr;
107
108#if DNS_DEBUG
109 /* dump hostent */
110 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_name == %s\n", s_hostent.h_name));
111 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases == 0x%08lX\n",(u32_t)(s_hostent.h_aliases)));
112 if (s_hostent.h_aliases != NULL) {
113 u8_t idx;
114 for ( idx=0; s_hostent.h_aliases[idx]; idx++) {
115 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == 0x%08lX\n", idx, s_hostent.h_aliases[idx]));
116 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_aliases[%i]-> == %s\n", idx, s_hostent.h_aliases[idx]));
117 }
118 }
119 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addrtype == %lu\n", (u32_t)(s_hostent.h_addrtype)));
120 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_length == %lu\n", (u32_t)(s_hostent.h_length)));
121 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list == 0x%08lX\n", s_hostent.h_addr_list));
122 if (s_hostent.h_addr_list != NULL) {
123 u8_t idx;
124 for ( idx=0; s_hostent.h_addr_list[idx]; idx++) {
125 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i] == 0x%08lX\n", idx, s_hostent.h_addr_list[idx]));
126 LWIP_DEBUGF(DNS_DEBUG, ("hostent.h_addr_list[%i]-> == %s\n", idx, inet_ntoa(*((struct in_addr*)(s_hostent.h_addr_list[idx])))));
127 }
128 }
129#endif /* DNS_DEBUG */
130
131#if LWIP_DNS_API_HOSTENT_STORAGE
132 /* this function should return the "per-thread" hostent after copy from s_hostent */
133 return sys_thread_hostent(&s_hostent);
134#else
135 return &s_hostent;
136#endif /* LWIP_DNS_API_HOSTENT_STORAGE */
137}
138
139/**
140 * Thread-safe variant of lwip_gethostbyname: instead of using a static
141 * buffer, this function takes buffer and errno pointers as arguments
142 * and uses these for the result.
143 *
144 * @param name the hostname to resolve
145 * @param ret pre-allocated struct where to store the result
146 * @param buf pre-allocated buffer where to store additional data
147 * @param buflen the size of buf
148 * @param result pointer to a hostent pointer that is set to ret on success
149 * and set to zero on error
150 * @param h_errnop pointer to an int where to store errors (instead of modifying
151 * the global h_errno)
152 * @return 0 on success, non-zero on error, additional error information
153 * is stored in *h_errnop instead of h_errno to be thread-safe
154 */
155int
156lwip_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
157 size_t buflen, struct hostent **result, int *h_errnop)
158{
159 err_t err;
160 struct gethostbyname_r_helper *h;
161 char *hostname;
162 size_t namelen;
163 int lh_errno;
164
165 if (h_errnop == NULL) {
166 /* ensure h_errnop is never NULL */
167 h_errnop = &lh_errno;
168 }
169
170 if (result == NULL) {
171 /* not all arguments given */
172 *h_errnop = EINVAL;
173 return -1;
174 }
175 /* first thing to do: set *result to nothing */
176 *result = NULL;
177 if ((name == NULL) || (ret == NULL) || (buf == 0)) {
178 /* not all arguments given */
179 *h_errnop = EINVAL;
180 return -1;
181 }
182
183 namelen = strlen(name);
184 if (buflen < (sizeof(struct gethostbyname_r_helper) + namelen + 1 + (MEM_ALIGNMENT - 1))) {
185 /* buf can't hold the data needed + a copy of name */
186 *h_errnop = ERANGE;
187 return -1;
188 }
189
190 h = (struct gethostbyname_r_helper*)LWIP_MEM_ALIGN(buf);
191 hostname = ((char*)h) + sizeof(struct gethostbyname_r_helper);
192
193 /* query host IP address */
194 err = netconn_gethostbyname(name, &(h->addr));
195 if (err != ERR_OK) {
196 LWIP_DEBUGF(DNS_DEBUG, ("lwip_gethostbyname(%s) failed, err=%d\n", name, err));
197 *h_errnop = ENSRNOTFOUND;
198 return -1;
199 }
200
201 /* copy the hostname into buf */
202 MEMCPY(hostname, name, namelen);
203 hostname[namelen] = 0;
204
205 /* fill hostent */
206 h->addrs = &(h->addr);
207 h->aliases = NULL;
208 ret->h_name = (char*)hostname;
209 ret->h_aliases = &(h->aliases);
210 ret->h_addrtype = AF_INET;
211 ret->h_length = sizeof(struct ip_addr);
212 ret->h_addr_list = (char**)&(h->addrs);
213
214 /* set result != NULL */
215 *result = ret;
216
217 /* return success */
218 return 0;
219}
220
221/**
222 * Frees one or more addrinfo structures returned by getaddrinfo(), along with
223 * any additional storage associated with those structures. If the ai_next field
224 * of the structure is not null, the entire list of structures is freed.
225 *
226 * @param ai struct addrinfo to free
227 */
228void
229lwip_freeaddrinfo(struct addrinfo *ai)
230{
231 struct addrinfo *next;
232
233 while (ai != NULL) {
234 if (ai->ai_addr != NULL) {
235 mem_free(ai->ai_addr);
236 }
237 if (ai->ai_canonname != NULL) {
238 mem_free(ai->ai_canonname);
239 }
240 next = ai->ai_next;
241 mem_free(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 */
265int
266lwip_getaddrinfo(const char *nodename, const char *servname,
267 const struct addrinfo *hints, struct addrinfo **res)
268{
269 err_t err;
270 struct ip_addr addr;
271 struct addrinfo *ai;
272 struct sockaddr_in *sa = NULL;
273 int port_nr = 0;
274
275 if (res == NULL) {
276 return EAI_FAIL;
277 }
278 *res = NULL;
279 if ((nodename == NULL) && (servname == NULL)) {
280 return EAI_NONAME;
281 }
282
283 if (servname != NULL) {
284 /* service name specified: convert to port number
285 * @todo?: currently, only ASCII integers (port numbers) are supported! */
286 port_nr = atoi(servname);
287 if ((port_nr <= 0) || (port_nr > 0xffff)) {
288 return EAI_SERVICE;
289 }
290 }
291
292 if (nodename != NULL) {
293 /* service location specified, try to resolve */
294 err = netconn_gethostbyname(nodename, &addr);
295 if (err != ERR_OK) {
296 return EAI_FAIL;
297 }
298 } else {
299 /* service location specified, use loopback address */
300 addr.addr = INADDR_LOOPBACK;
301 }
302
303 ai = mem_malloc(sizeof(struct addrinfo));
304 if (ai == NULL) {
305 goto memerr;
306 }
307 memset(ai, 0, sizeof(struct addrinfo));
308 sa = mem_malloc(sizeof(struct sockaddr_in));
309 if (sa == NULL) {
310 goto memerr;
311 }
312 memset(sa, 0, sizeof(struct sockaddr_in));
313 /* set up sockaddr */
314 sa->sin_addr.s_addr = addr.addr;
315 sa->sin_family = AF_INET;
316 sa->sin_len = sizeof(struct sockaddr_in);
317 sa->sin_port = htons(port_nr);
318
319 /* set up addrinfo */
320 ai->ai_family = AF_INET;
321 if (hints != NULL) {
322 /* copy socktype & protocol from hints if specified */
323 ai->ai_socktype = hints->ai_socktype;
324 ai->ai_protocol = hints->ai_protocol;
325 }
326 if (nodename != NULL) {
327 /* copy nodename to canonname if specified */
328 size_t namelen = strlen(nodename);
329 ai->ai_canonname = mem_malloc(namelen + 1);
330 if (ai->ai_canonname == NULL) {
331 goto memerr;
332 }
333 MEMCPY(ai->ai_canonname, nodename, namelen);
334 ai->ai_canonname[namelen] = 0;
335 }
336 ai->ai_addrlen = sizeof(struct sockaddr_in);
337 ai->ai_addr = (struct sockaddr*)sa;
338
339 *res = ai;
340
341 return 0;
342memerr:
343 if (ai != NULL) {
344 mem_free(ai);
345 }
346 if (sa != NULL) {
347 mem_free(sa);
348 }
349 return EAI_MEMORY;
350}
351
352#endif /* LWIP_DNS && LWIP_SOCKET */
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