hostip4.c 10 KB

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  1. /***************************************************************************
  2. * _ _ ____ _
  3. * Project ___| | | | _ \| |
  4. * / __| | | | |_) | |
  5. * | (__| |_| | _ <| |___
  6. * \___|\___/|_| \_\_____|
  7. *
  8. * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
  9. *
  10. * This software is licensed as described in the file COPYING, which
  11. * you should have received as part of this distribution. The terms
  12. * are also available at https://curl.haxx.se/docs/copyright.html.
  13. *
  14. * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15. * copies of the Software, and permit persons to whom the Software is
  16. * furnished to do so, under the terms of the COPYING file.
  17. *
  18. * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19. * KIND, either express or implied.
  20. *
  21. ***************************************************************************/
  22. #include "curl_setup.h"
  23. /***********************************************************************
  24. * Only for plain IPv4 builds
  25. **********************************************************************/
  26. #ifdef CURLRES_IPV4 /* plain IPv4 code coming up */
  27. #ifdef HAVE_NETINET_IN_H
  28. #include <netinet/in.h>
  29. #endif
  30. #ifdef HAVE_NETDB_H
  31. #include <netdb.h>
  32. #endif
  33. #ifdef HAVE_ARPA_INET_H
  34. #include <arpa/inet.h>
  35. #endif
  36. #ifdef __VMS
  37. #include <in.h>
  38. #include <inet.h>
  39. #endif
  40. #ifdef HAVE_PROCESS_H
  41. #include <process.h>
  42. #endif
  43. #include "urldata.h"
  44. #include "sendf.h"
  45. #include "hostip.h"
  46. #include "hash.h"
  47. #include "share.h"
  48. #include "strerror.h"
  49. #include "url.h"
  50. #include "inet_pton.h"
  51. /* The last 3 #include files should be in this order */
  52. #include "curl_printf.h"
  53. #include "curl_memory.h"
  54. #include "memdebug.h"
  55. /*
  56. * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've
  57. * been set and returns TRUE if they are OK.
  58. */
  59. bool Curl_ipvalid(struct connectdata *conn)
  60. {
  61. if(conn->ip_version == CURL_IPRESOLVE_V6)
  62. /* An IPv6 address was requested and we can't get/use one */
  63. return FALSE;
  64. return TRUE; /* OK, proceed */
  65. }
  66. #ifdef CURLRES_SYNCH
  67. /*
  68. * Curl_getaddrinfo() - the IPv4 synchronous version.
  69. *
  70. * The original code to this function was from the Dancer source code, written
  71. * by Bjorn Reese, it has since been patched and modified considerably.
  72. *
  73. * gethostbyname_r() is the thread-safe version of the gethostbyname()
  74. * function. When we build for plain IPv4, we attempt to use this
  75. * function. There are _three_ different gethostbyname_r() versions, and we
  76. * detect which one this platform supports in the configure script and set up
  77. * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or
  78. * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME
  79. * has the corresponding rules. This is primarily on *nix. Note that some unix
  80. * flavours have thread-safe versions of the plain gethostbyname() etc.
  81. *
  82. */
  83. Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
  84. const char *hostname,
  85. int port,
  86. int *waitp)
  87. {
  88. Curl_addrinfo *ai = NULL;
  89. #ifdef CURL_DISABLE_VERBOSE_STRINGS
  90. (void)conn;
  91. #endif
  92. *waitp = 0; /* synchronous response only */
  93. ai = Curl_ipv4_resolve_r(hostname, port);
  94. if(!ai)
  95. infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname);
  96. return ai;
  97. }
  98. #endif /* CURLRES_SYNCH */
  99. #endif /* CURLRES_IPV4 */
  100. #if defined(CURLRES_IPV4) && !defined(CURLRES_ARES)
  101. /*
  102. * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function.
  103. *
  104. * This is used for both synchronous and asynchronous resolver builds,
  105. * implying that only threadsafe code and function calls may be used.
  106. *
  107. */
  108. Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname,
  109. int port)
  110. {
  111. #if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3)
  112. int res;
  113. #endif
  114. Curl_addrinfo *ai = NULL;
  115. struct hostent *h = NULL;
  116. struct in_addr in;
  117. struct hostent *buf = NULL;
  118. if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
  119. /* This is a dotted IP address 123.123.123.123-style */
  120. return Curl_ip2addr(AF_INET, &in, hostname, port);
  121. #if defined(HAVE_GETADDRINFO_THREADSAFE)
  122. else {
  123. struct addrinfo hints;
  124. char sbuf[12];
  125. char *sbufptr = NULL;
  126. memset(&hints, 0, sizeof(hints));
  127. hints.ai_family = PF_INET;
  128. hints.ai_socktype = SOCK_STREAM;
  129. if(port) {
  130. msnprintf(sbuf, sizeof(sbuf), "%d", port);
  131. sbufptr = sbuf;
  132. }
  133. (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai);
  134. #elif defined(HAVE_GETHOSTBYNAME_R)
  135. /*
  136. * gethostbyname_r() is the preferred resolve function for many platforms.
  137. * Since there are three different versions of it, the following code is
  138. * somewhat #ifdef-ridden.
  139. */
  140. else {
  141. int h_errnop;
  142. buf = calloc(1, CURL_HOSTENT_SIZE);
  143. if(!buf)
  144. return NULL; /* major failure */
  145. /*
  146. * The clearing of the buffer is a workaround for a gethostbyname_r bug in
  147. * qnx nto and it is also _required_ for some of these functions on some
  148. * platforms.
  149. */
  150. #if defined(HAVE_GETHOSTBYNAME_R_5)
  151. /* Solaris, IRIX and more */
  152. h = gethostbyname_r(hostname,
  153. (struct hostent *)buf,
  154. (char *)buf + sizeof(struct hostent),
  155. CURL_HOSTENT_SIZE - sizeof(struct hostent),
  156. &h_errnop);
  157. /* If the buffer is too small, it returns NULL and sets errno to
  158. * ERANGE. The errno is thread safe if this is compiled with
  159. * -D_REENTRANT as then the 'errno' variable is a macro defined to get
  160. * used properly for threads.
  161. */
  162. if(h) {
  163. ;
  164. }
  165. else
  166. #elif defined(HAVE_GETHOSTBYNAME_R_6)
  167. /* Linux */
  168. (void)gethostbyname_r(hostname,
  169. (struct hostent *)buf,
  170. (char *)buf + sizeof(struct hostent),
  171. CURL_HOSTENT_SIZE - sizeof(struct hostent),
  172. &h, /* DIFFERENCE */
  173. &h_errnop);
  174. /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a
  175. * sudden this function returns EAGAIN if the given buffer size is too
  176. * small. Previous versions are known to return ERANGE for the same
  177. * problem.
  178. *
  179. * This wouldn't be such a big problem if older versions wouldn't
  180. * sometimes return EAGAIN on a common failure case. Alas, we can't
  181. * assume that EAGAIN *or* ERANGE means ERANGE for any given version of
  182. * glibc.
  183. *
  184. * For now, we do that and thus we may call the function repeatedly and
  185. * fail for older glibc versions that return EAGAIN, until we run out of
  186. * buffer size (step_size grows beyond CURL_HOSTENT_SIZE).
  187. *
  188. * If anyone has a better fix, please tell us!
  189. *
  190. * -------------------------------------------------------------------
  191. *
  192. * On October 23rd 2003, Dan C dug up more details on the mysteries of
  193. * gethostbyname_r() in glibc:
  194. *
  195. * In glibc 2.2.5 the interface is different (this has also been
  196. * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't
  197. * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32
  198. * (shipped/upgraded by Redhat 7.2) don't show this behavior!
  199. *
  200. * In this "buggy" version, the return code is -1 on error and 'errno'
  201. * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a
  202. * thread-safe variable.
  203. */
  204. if(!h) /* failure */
  205. #elif defined(HAVE_GETHOSTBYNAME_R_3)
  206. /* AIX, Digital Unix/Tru64, HPUX 10, more? */
  207. /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of
  208. * the plain fact that it does not return unique full buffers on each
  209. * call, but instead several of the pointers in the hostent structs will
  210. * point to the same actual data! This have the unfortunate down-side that
  211. * our caching system breaks down horribly. Luckily for us though, AIX 4.3
  212. * and more recent versions have a "completely thread-safe"[*] libc where
  213. * all the data is stored in thread-specific memory areas making calls to
  214. * the plain old gethostbyname() work fine even for multi-threaded
  215. * programs.
  216. *
  217. * This AIX 4.3 or later detection is all made in the configure script.
  218. *
  219. * Troels Walsted Hansen helped us work this out on March 3rd, 2003.
  220. *
  221. * [*] = much later we've found out that it isn't at all "completely
  222. * thread-safe", but at least the gethostbyname() function is.
  223. */
  224. if(CURL_HOSTENT_SIZE >=
  225. (sizeof(struct hostent) + sizeof(struct hostent_data))) {
  226. /* August 22nd, 2000: Albert Chin-A-Young brought an updated version
  227. * that should work! September 20: Richard Prescott worked on the buffer
  228. * size dilemma.
  229. */
  230. res = gethostbyname_r(hostname,
  231. (struct hostent *)buf,
  232. (struct hostent_data *)((char *)buf +
  233. sizeof(struct hostent)));
  234. h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */
  235. }
  236. else
  237. res = -1; /* failure, too smallish buffer size */
  238. if(!res) { /* success */
  239. h = buf; /* result expected in h */
  240. /* This is the worst kind of the different gethostbyname_r() interfaces.
  241. * Since we don't know how big buffer this particular lookup required,
  242. * we can't realloc down the huge alloc without doing closer analysis of
  243. * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every
  244. * name lookup. Fixing this would require an extra malloc() and then
  245. * calling Curl_addrinfo_copy() that subsequent realloc()s down the new
  246. * memory area to the actually used amount.
  247. */
  248. }
  249. else
  250. #endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */
  251. {
  252. h = NULL; /* set return code to NULL */
  253. free(buf);
  254. }
  255. #else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
  256. /*
  257. * Here is code for platforms that don't have a thread safe
  258. * getaddrinfo() nor gethostbyname_r() function or for which
  259. * gethostbyname() is the preferred one.
  260. */
  261. else {
  262. h = gethostbyname((void *)hostname);
  263. #endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
  264. }
  265. if(h) {
  266. ai = Curl_he2ai(h, port);
  267. if(buf) /* used a *_r() function */
  268. free(buf);
  269. }
  270. return ai;
  271. }
  272. #endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */