1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel (at) 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 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 /* 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 /*********************************************************************** 57 * Only for plain IPv4 builds 58 **********************************************************************/ 59 #ifdef CURLRES_IPV4 /* plain IPv4 code coming up */ 60 /* 61 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've 62 * been set and returns TRUE if they are OK. 63 */ 64 bool Curl_ipvalid(struct connectdata *conn) 65 { 66 if(conn->ip_version == CURL_IPRESOLVE_V6) 67 /* An IPv6 address was requested and we can't get/use one */ 68 return FALSE; 69 70 return TRUE; /* OK, proceed */ 71 } 72 73 #ifdef CURLRES_SYNCH 74 75 /* 76 * Curl_getaddrinfo() - the IPv4 synchronous version. 77 * 78 * The original code to this function was from the Dancer source code, written 79 * by Bjorn Reese, it has since been patched and modified considerably. 80 * 81 * gethostbyname_r() is the thread-safe version of the gethostbyname() 82 * function. When we build for plain IPv4, we attempt to use this 83 * function. There are _three_ different gethostbyname_r() versions, and we 84 * detect which one this platform supports in the configure script and set up 85 * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or 86 * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME 87 * has the corresponding rules. This is primarily on *nix. Note that some unix 88 * flavours have thread-safe versions of the plain gethostbyname() etc. 89 * 90 */ 91 Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, 92 const char *hostname, 93 int port, 94 int *waitp) 95 { 96 Curl_addrinfo *ai = NULL; 97 98 #ifdef CURL_DISABLE_VERBOSE_STRINGS 99 (void)conn; 100 #endif 101 102 *waitp = 0; /* synchronous response only */ 103 104 ai = Curl_ipv4_resolve_r(hostname, port); 105 if(!ai) 106 infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname); 107 108 return ai; 109 } 110 #endif /* CURLRES_SYNCH */ 111 #endif /* CURLRES_IPV4 */ 112 113 #if defined(CURLRES_IPV4) && !defined(CURLRES_ARES) 114 115 /* 116 * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. 117 * 118 * This is used for both synchronous and asynchronous resolver builds, 119 * implying that only threadsafe code and function calls may be used. 120 * 121 */ 122 Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, 123 int port) 124 { 125 #if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3) 126 int res; 127 #endif 128 Curl_addrinfo *ai = NULL; 129 struct hostent *h = NULL; 130 struct in_addr in; 131 struct hostent *buf = NULL; 132 133 if(Curl_inet_pton(AF_INET, hostname, &in) > 0) 134 /* This is a dotted IP address 123.123.123.123-style */ 135 return Curl_ip2addr(AF_INET, &in, hostname, port); 136 137 #if defined(HAVE_GETADDRINFO_THREADSAFE) 138 else { 139 struct addrinfo hints; 140 char sbuf[12]; 141 char *sbufptr = NULL; 142 143 memset(&hints, 0, sizeof(hints)); 144 hints.ai_family = PF_INET; 145 hints.ai_socktype = SOCK_STREAM; 146 if(port) { 147 snprintf(sbuf, sizeof(sbuf), "%d", port); 148 sbufptr = sbuf; 149 } 150 151 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); 152 153 #elif defined(HAVE_GETHOSTBYNAME_R) 154 /* 155 * gethostbyname_r() is the preferred resolve function for many platforms. 156 * Since there are three different versions of it, the following code is 157 * somewhat #ifdef-ridden. 158 */ 159 else { 160 int h_errnop; 161 162 buf = calloc(1, CURL_HOSTENT_SIZE); 163 if(!buf) 164 return NULL; /* major failure */ 165 /* 166 * The clearing of the buffer is a workaround for a gethostbyname_r bug in 167 * qnx nto and it is also _required_ for some of these functions on some 168 * platforms. 169 */ 170 171 #if defined(HAVE_GETHOSTBYNAME_R_5) 172 /* Solaris, IRIX and more */ 173 h = gethostbyname_r(hostname, 174 (struct hostent *)buf, 175 (char *)buf + sizeof(struct hostent), 176 CURL_HOSTENT_SIZE - sizeof(struct hostent), 177 &h_errnop); 178 179 /* If the buffer is too small, it returns NULL and sets errno to 180 * ERANGE. The errno is thread safe if this is compiled with 181 * -D_REENTRANT as then the 'errno' variable is a macro defined to get 182 * used properly for threads. 183 */ 184 185 if(h) { 186 ; 187 } 188 else 189 #elif defined(HAVE_GETHOSTBYNAME_R_6) 190 /* Linux */ 191 192 (void)gethostbyname_r(hostname, 193 (struct hostent *)buf, 194 (char *)buf + sizeof(struct hostent), 195 CURL_HOSTENT_SIZE - sizeof(struct hostent), 196 &h, /* DIFFERENCE */ 197 &h_errnop); 198 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a 199 * sudden this function returns EAGAIN if the given buffer size is too 200 * small. Previous versions are known to return ERANGE for the same 201 * problem. 202 * 203 * This wouldn't be such a big problem if older versions wouldn't 204 * sometimes return EAGAIN on a common failure case. Alas, we can't 205 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of 206 * glibc. 207 * 208 * For now, we do that and thus we may call the function repeatedly and 209 * fail for older glibc versions that return EAGAIN, until we run out of 210 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). 211 * 212 * If anyone has a better fix, please tell us! 213 * 214 * ------------------------------------------------------------------- 215 * 216 * On October 23rd 2003, Dan C dug up more details on the mysteries of 217 * gethostbyname_r() in glibc: 218 * 219 * In glibc 2.2.5 the interface is different (this has also been 220 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't 221 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 222 * (shipped/upgraded by Redhat 7.2) don't show this behavior! 223 * 224 * In this "buggy" version, the return code is -1 on error and 'errno' 225 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a 226 * thread-safe variable. 227 */ 228 229 if(!h) /* failure */ 230 #elif defined(HAVE_GETHOSTBYNAME_R_3) 231 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ 232 233 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of 234 * the plain fact that it does not return unique full buffers on each 235 * call, but instead several of the pointers in the hostent structs will 236 * point to the same actual data! This have the unfortunate down-side that 237 * our caching system breaks down horribly. Luckily for us though, AIX 4.3 238 * and more recent versions have a "completely thread-safe"[*] libc where 239 * all the data is stored in thread-specific memory areas making calls to 240 * the plain old gethostbyname() work fine even for multi-threaded 241 * programs. 242 * 243 * This AIX 4.3 or later detection is all made in the configure script. 244 * 245 * Troels Walsted Hansen helped us work this out on March 3rd, 2003. 246 * 247 * [*] = much later we've found out that it isn't at all "completely 248 * thread-safe", but at least the gethostbyname() function is. 249 */ 250 251 if(CURL_HOSTENT_SIZE >= 252 (sizeof(struct hostent)+sizeof(struct hostent_data))) { 253 254 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version 255 * that should work! September 20: Richard Prescott worked on the buffer 256 * size dilemma. 257 */ 258 259 res = gethostbyname_r(hostname, 260 (struct hostent *)buf, 261 (struct hostent_data *)((char *)buf + 262 sizeof(struct hostent))); 263 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ 264 } 265 else 266 res = -1; /* failure, too smallish buffer size */ 267 268 if(!res) { /* success */ 269 270 h = buf; /* result expected in h */ 271 272 /* This is the worst kind of the different gethostbyname_r() interfaces. 273 * Since we don't know how big buffer this particular lookup required, 274 * we can't realloc down the huge alloc without doing closer analysis of 275 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every 276 * name lookup. Fixing this would require an extra malloc() and then 277 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new 278 * memory area to the actually used amount. 279 */ 280 } 281 else 282 #endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ 283 { 284 h = NULL; /* set return code to NULL */ 285 free(buf); 286 } 287 #else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 288 /* 289 * Here is code for platforms that don't have a thread safe 290 * getaddrinfo() nor gethostbyname_r() function or for which 291 * gethostbyname() is the preferred one. 292 */ 293 else { 294 h = gethostbyname((void*)hostname); 295 #endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 296 } 297 298 if(h) { 299 ai = Curl_he2ai(h, port); 300 301 if(buf) /* used a *_r() function */ 302 free(buf); 303 } 304 305 return ai; 306 } 307 #endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */ 308
