1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2017, 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 /*********************************************************************** 26 * Only for plain IPv4 builds 27 **********************************************************************/ 28 #ifdef CURLRES_IPV4 /* plain IPv4 code coming up */ 29 30 #ifdef HAVE_NETINET_IN_H 31 #include <netinet/in.h> 32 #endif 33 #ifdef HAVE_NETDB_H 34 #include <netdb.h> 35 #endif 36 #ifdef HAVE_ARPA_INET_H 37 #include <arpa/inet.h> 38 #endif 39 #ifdef __VMS 40 #include <in.h> 41 #include <inet.h> 42 #endif 43 44 #ifdef HAVE_PROCESS_H 45 #include <process.h> 46 #endif 47 48 #include "urldata.h" 49 #include "sendf.h" 50 #include "hostip.h" 51 #include "hash.h" 52 #include "share.h" 53 #include "strerror.h" 54 #include "url.h" 55 #include "inet_pton.h" 56 /* The last 3 #include files should be in this order */ 57 #include "curl_printf.h" 58 #include "curl_memory.h" 59 #include "memdebug.h" 60 61 /* 62 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've 63 * been set and returns TRUE if they are OK. 64 */ 65 bool Curl_ipvalid(struct connectdata *conn) 66 { 67 if(conn->ip_version == CURL_IPRESOLVE_V6) 68 /* An IPv6 address was requested and we can't get/use one */ 69 return FALSE; 70 71 return TRUE; /* OK, proceed */ 72 } 73 74 #ifdef CURLRES_SYNCH 75 76 /* 77 * Curl_getaddrinfo() - the IPv4 synchronous version. 78 * 79 * The original code to this function was from the Dancer source code, written 80 * by Bjorn Reese, it has since been patched and modified considerably. 81 * 82 * gethostbyname_r() is the thread-safe version of the gethostbyname() 83 * function. When we build for plain IPv4, we attempt to use this 84 * function. There are _three_ different gethostbyname_r() versions, and we 85 * detect which one this platform supports in the configure script and set up 86 * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or 87 * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME 88 * has the corresponding rules. This is primarily on *nix. Note that some unix 89 * flavours have thread-safe versions of the plain gethostbyname() etc. 90 * 91 */ 92 Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, 93 const char *hostname, 94 int port, 95 int *waitp) 96 { 97 Curl_addrinfo *ai = NULL; 98 99 #ifdef CURL_DISABLE_VERBOSE_STRINGS 100 (void)conn; 101 #endif 102 103 *waitp = 0; /* synchronous response only */ 104 105 ai = Curl_ipv4_resolve_r(hostname, port); 106 if(!ai) 107 infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname); 108 109 return ai; 110 } 111 #endif /* CURLRES_SYNCH */ 112 #endif /* CURLRES_IPV4 */ 113 114 #if defined(CURLRES_IPV4) && !defined(CURLRES_ARES) 115 116 /* 117 * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. 118 * 119 * This is used for both synchronous and asynchronous resolver builds, 120 * implying that only threadsafe code and function calls may be used. 121 * 122 */ 123 Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, 124 int port) 125 { 126 #if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3) 127 int res; 128 #endif 129 Curl_addrinfo *ai = NULL; 130 struct hostent *h = NULL; 131 struct in_addr in; 132 struct hostent *buf = NULL; 133 134 if(Curl_inet_pton(AF_INET, hostname, &in) > 0) 135 /* This is a dotted IP address 123.123.123.123-style */ 136 return Curl_ip2addr(AF_INET, &in, hostname, port); 137 138 #if defined(HAVE_GETADDRINFO_THREADSAFE) 139 else { 140 struct addrinfo hints; 141 char sbuf[12]; 142 char *sbufptr = NULL; 143 144 memset(&hints, 0, sizeof(hints)); 145 hints.ai_family = PF_INET; 146 hints.ai_socktype = SOCK_STREAM; 147 if(port) { 148 snprintf(sbuf, sizeof(sbuf), "%d", port); 149 sbufptr = sbuf; 150 } 151 152 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); 153 154 #elif defined(HAVE_GETHOSTBYNAME_R) 155 /* 156 * gethostbyname_r() is the preferred resolve function for many platforms. 157 * Since there are three different versions of it, the following code is 158 * somewhat #ifdef-ridden. 159 */ 160 else { 161 int h_errnop; 162 163 buf = calloc(1, CURL_HOSTENT_SIZE); 164 if(!buf) 165 return NULL; /* major failure */ 166 /* 167 * The clearing of the buffer is a workaround for a gethostbyname_r bug in 168 * qnx nto and it is also _required_ for some of these functions on some 169 * platforms. 170 */ 171 172 #if defined(HAVE_GETHOSTBYNAME_R_5) 173 /* Solaris, IRIX and more */ 174 h = gethostbyname_r(hostname, 175 (struct hostent *)buf, 176 (char *)buf + sizeof(struct hostent), 177 CURL_HOSTENT_SIZE - sizeof(struct hostent), 178 &h_errnop); 179 180 /* If the buffer is too small, it returns NULL and sets errno to 181 * ERANGE. The errno is thread safe if this is compiled with 182 * -D_REENTRANT as then the 'errno' variable is a macro defined to get 183 * used properly for threads. 184 */ 185 186 if(h) { 187 ; 188 } 189 else 190 #elif defined(HAVE_GETHOSTBYNAME_R_6) 191 /* Linux */ 192 193 (void)gethostbyname_r(hostname, 194 (struct hostent *)buf, 195 (char *)buf + sizeof(struct hostent), 196 CURL_HOSTENT_SIZE - sizeof(struct hostent), 197 &h, /* DIFFERENCE */ 198 &h_errnop); 199 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a 200 * sudden this function returns EAGAIN if the given buffer size is too 201 * small. Previous versions are known to return ERANGE for the same 202 * problem. 203 * 204 * This wouldn't be such a big problem if older versions wouldn't 205 * sometimes return EAGAIN on a common failure case. Alas, we can't 206 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of 207 * glibc. 208 * 209 * For now, we do that and thus we may call the function repeatedly and 210 * fail for older glibc versions that return EAGAIN, until we run out of 211 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). 212 * 213 * If anyone has a better fix, please tell us! 214 * 215 * ------------------------------------------------------------------- 216 * 217 * On October 23rd 2003, Dan C dug up more details on the mysteries of 218 * gethostbyname_r() in glibc: 219 * 220 * In glibc 2.2.5 the interface is different (this has also been 221 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't 222 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 223 * (shipped/upgraded by Redhat 7.2) don't show this behavior! 224 * 225 * In this "buggy" version, the return code is -1 on error and 'errno' 226 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a 227 * thread-safe variable. 228 */ 229 230 if(!h) /* failure */ 231 #elif defined(HAVE_GETHOSTBYNAME_R_3) 232 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ 233 234 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of 235 * the plain fact that it does not return unique full buffers on each 236 * call, but instead several of the pointers in the hostent structs will 237 * point to the same actual data! This have the unfortunate down-side that 238 * our caching system breaks down horribly. Luckily for us though, AIX 4.3 239 * and more recent versions have a "completely thread-safe"[*] libc where 240 * all the data is stored in thread-specific memory areas making calls to 241 * the plain old gethostbyname() work fine even for multi-threaded 242 * programs. 243 * 244 * This AIX 4.3 or later detection is all made in the configure script. 245 * 246 * Troels Walsted Hansen helped us work this out on March 3rd, 2003. 247 * 248 * [*] = much later we've found out that it isn't at all "completely 249 * thread-safe", but at least the gethostbyname() function is. 250 */ 251 252 if(CURL_HOSTENT_SIZE >= 253 (sizeof(struct hostent) + sizeof(struct hostent_data))) { 254 255 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version 256 * that should work! September 20: Richard Prescott worked on the buffer 257 * size dilemma. 258 */ 259 260 res = gethostbyname_r(hostname, 261 (struct hostent *)buf, 262 (struct hostent_data *)((char *)buf + 263 sizeof(struct hostent))); 264 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ 265 } 266 else 267 res = -1; /* failure, too smallish buffer size */ 268 269 if(!res) { /* success */ 270 271 h = buf; /* result expected in h */ 272 273 /* This is the worst kind of the different gethostbyname_r() interfaces. 274 * Since we don't know how big buffer this particular lookup required, 275 * we can't realloc down the huge alloc without doing closer analysis of 276 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every 277 * name lookup. Fixing this would require an extra malloc() and then 278 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new 279 * memory area to the actually used amount. 280 */ 281 } 282 else 283 #endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ 284 { 285 h = NULL; /* set return code to NULL */ 286 free(buf); 287 } 288 #else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 289 /* 290 * Here is code for platforms that don't have a thread safe 291 * getaddrinfo() nor gethostbyname_r() function or for which 292 * gethostbyname() is the preferred one. 293 */ 294 else { 295 h = gethostbyname((void *)hostname); 296 #endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 297 } 298 299 if(h) { 300 ai = Curl_he2ai(h, port); 301 302 if(buf) /* used a *_r() function */ 303 free(buf); 304 } 305 306 return ai; 307 } 308 #endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */ 309
