1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2013, 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 http://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 23#include "curl_setup.h" 24 25#ifdef HAVE_NETINET_IN_H 26#include <netinet/in.h> 27#endif 28#ifdef HAVE_NETDB_H 29#include <netdb.h> 30#endif 31#ifdef HAVE_ARPA_INET_H 32#include <arpa/inet.h> 33#endif 34#ifdef __VMS 35#include <in.h> 36#include <inet.h> 37#endif 38 39#ifdef HAVE_PROCESS_H 40#include <process.h> 41#endif 42 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 52#define _MPRINTF_REPLACE /* use our functions only */ 53#include <curl/mprintf.h> 54 55#include "curl_memory.h" 56/* The last #include file should be: */ 57#include "memdebug.h" 58 59/*********************************************************************** 60 * Only for plain-ipv4 builds 61 **********************************************************************/ 62#ifdef CURLRES_IPV4 /* plain ipv4 code coming up */ 63/* 64 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've 65 * been set and returns TRUE if they are OK. 66 */ 67bool Curl_ipvalid(struct connectdata *conn) 68{ 69 if(conn->ip_version == CURL_IPRESOLVE_V6) 70 /* an ipv6 address was requested and we can't get/use one */ 71 return FALSE; 72 73 return TRUE; /* OK, proceed */ 74} 75 76#ifdef CURLRES_SYNCH 77 78/* 79 * Curl_getaddrinfo() - the ipv4 synchronous version. 80 * 81 * The original code to this function was from the Dancer source code, written 82 * by Bjorn Reese, it has since been patched and modified considerably. 83 * 84 * gethostbyname_r() is the thread-safe version of the gethostbyname() 85 * function. When we build for plain IPv4, we attempt to use this 86 * function. There are _three_ different gethostbyname_r() versions, and we 87 * detect which one this platform supports in the configure script and set up 88 * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or 89 * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME 90 * has the corresponding rules. This is primarily on *nix. Note that some unix 91 * flavours have thread-safe versions of the plain gethostbyname() etc. 92 * 93 */ 94Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, 95 const char *hostname, 96 int port, 97 int *waitp) 98{ 99 Curl_addrinfo *ai = NULL; 100 101#ifdef CURL_DISABLE_VERBOSE_STRINGS 102 (void)conn; 103#endif 104 105 *waitp = 0; /* synchronous response only */ 106 107 ai = Curl_ipv4_resolve_r(hostname, port); 108 if(!ai) 109 infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname); 110 111 return ai; 112} 113#endif /* CURLRES_SYNCH */ 114#endif /* CURLRES_IPV4 */ 115 116#if defined(CURLRES_IPV4) && !defined(CURLRES_ARES) 117 118/* 119 * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. 120 * 121 * This is used for both synchronous and asynchronous resolver builds, 122 * implying that only threadsafe code and function calls may be used. 123 * 124 */ 125Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, 126 int port) 127{ 128#if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3) 129 int res; 130#endif 131 Curl_addrinfo *ai = NULL; 132 struct hostent *h = NULL; 133 struct in_addr in; 134 struct hostent *buf = NULL; 135 136 if(Curl_inet_pton(AF_INET, hostname, &in) > 0) 137 /* This is a dotted IP address 123.123.123.123-style */ 138 return Curl_ip2addr(AF_INET, &in, hostname, port); 139 140#if defined(HAVE_GETADDRINFO_THREADSAFE) 141 else { 142 struct addrinfo hints; 143 char sbuf[12]; 144 char *sbufptr = NULL; 145 146 memset(&hints, 0, sizeof(hints)); 147 hints.ai_family = PF_INET; 148 hints.ai_socktype = SOCK_STREAM; 149 if(port) { 150 snprintf(sbuf, sizeof(sbuf), "%d", port); 151 sbufptr = sbuf; 152 } 153 154 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); 155 156#elif defined(HAVE_GETHOSTBYNAME_R) 157 /* 158 * gethostbyname_r() is the preferred resolve function for many platforms. 159 * Since there are three different versions of it, the following code is 160 * somewhat #ifdef-ridden. 161 */ 162 else { 163 int h_errnop; 164 165 buf = calloc(1, CURL_HOSTENT_SIZE); 166 if(!buf) 167 return NULL; /* major failure */ 168 /* 169 * The clearing of the buffer is a workaround for a gethostbyname_r bug in 170 * qnx nto and it is also _required_ for some of these functions on some 171 * platforms. 172 */ 173 174#if defined(HAVE_GETHOSTBYNAME_R_5) 175 /* Solaris, IRIX and more */ 176 h = gethostbyname_r(hostname, 177 (struct hostent *)buf, 178 (char *)buf + sizeof(struct hostent), 179 CURL_HOSTENT_SIZE - sizeof(struct hostent), 180 &h_errnop); 181 182 /* If the buffer is too small, it returns NULL and sets errno to 183 * ERANGE. The errno is thread safe if this is compiled with 184 * -D_REENTRANT as then the 'errno' variable is a macro defined to get 185 * used properly for threads. 186 */ 187 188 if(h) { 189 ; 190 } 191 else 192#elif defined(HAVE_GETHOSTBYNAME_R_6) 193 /* Linux */ 194 195 (void)gethostbyname_r(hostname, 196 (struct hostent *)buf, 197 (char *)buf + sizeof(struct hostent), 198 CURL_HOSTENT_SIZE - sizeof(struct hostent), 199 &h, /* DIFFERENCE */ 200 &h_errnop); 201 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a 202 * sudden this function returns EAGAIN if the given buffer size is too 203 * small. Previous versions are known to return ERANGE for the same 204 * problem. 205 * 206 * This wouldn't be such a big problem if older versions wouldn't 207 * sometimes return EAGAIN on a common failure case. Alas, we can't 208 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of 209 * glibc. 210 * 211 * For now, we do that and thus we may call the function repeatedly and 212 * fail for older glibc versions that return EAGAIN, until we run out of 213 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). 214 * 215 * If anyone has a better fix, please tell us! 216 * 217 * ------------------------------------------------------------------- 218 * 219 * On October 23rd 2003, Dan C dug up more details on the mysteries of 220 * gethostbyname_r() in glibc: 221 * 222 * In glibc 2.2.5 the interface is different (this has also been 223 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't 224 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 225 * (shipped/upgraded by Redhat 7.2) don't show this behavior! 226 * 227 * In this "buggy" version, the return code is -1 on error and 'errno' 228 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a 229 * thread-safe variable. 230 */ 231 232 if(!h) /* failure */ 233#elif defined(HAVE_GETHOSTBYNAME_R_3) 234 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ 235 236 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of 237 * the plain fact that it does not return unique full buffers on each 238 * call, but instead several of the pointers in the hostent structs will 239 * point to the same actual data! This have the unfortunate down-side that 240 * our caching system breaks down horribly. Luckily for us though, AIX 4.3 241 * and more recent versions have a "completely thread-safe"[*] libc where 242 * all the data is stored in thread-specific memory areas making calls to 243 * the plain old gethostbyname() work fine even for multi-threaded 244 * programs. 245 * 246 * This AIX 4.3 or later detection is all made in the configure script. 247 * 248 * Troels Walsted Hansen helped us work this out on March 3rd, 2003. 249 * 250 * [*] = much later we've found out that it isn't at all "completely 251 * thread-safe", but at least the gethostbyname() function is. 252 */ 253 254 if(CURL_HOSTENT_SIZE >= 255 (sizeof(struct hostent)+sizeof(struct hostent_data))) { 256 257 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version 258 * that should work! September 20: Richard Prescott worked on the buffer 259 * size dilemma. 260 */ 261 262 res = gethostbyname_r(hostname, 263 (struct hostent *)buf, 264 (struct hostent_data *)((char *)buf + 265 sizeof(struct hostent))); 266 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ 267 } 268 else 269 res = -1; /* failure, too smallish buffer size */ 270 271 if(!res) { /* success */ 272 273 h = buf; /* result expected in h */ 274 275 /* This is the worst kind of the different gethostbyname_r() interfaces. 276 * Since we don't know how big buffer this particular lookup required, 277 * we can't realloc down the huge alloc without doing closer analysis of 278 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every 279 * name lookup. Fixing this would require an extra malloc() and then 280 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new 281 * memory area to the actually used amount. 282 */ 283 } 284 else 285#endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ 286 { 287 h = NULL; /* set return code to NULL */ 288 free(buf); 289 } 290#else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 291 /* 292 * Here is code for platforms that don't have a thread safe 293 * getaddrinfo() nor gethostbyname_r() function or for which 294 * gethostbyname() is the preferred one. 295 */ 296 else { 297 h = gethostbyname((void*)hostname); 298#endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 299 } 300 301 if(h) { 302 ai = Curl_he2ai(h, port); 303 304 if(buf) /* used a *_r() function */ 305 free(buf); 306 } 307 308 return ai; 309} 310#endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */ 311