1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 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.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 * SPDX-License-Identifier: curl 22 * 23 ***************************************************************************/ 24 25#include "curl_setup.h" 26 27/*********************************************************************** 28 * Only for plain IPv4 builds 29 **********************************************************************/ 30#ifdef CURLRES_IPV4 /* plain IPv4 code coming up */ 31 32#ifdef HAVE_NETINET_IN_H 33#include <netinet/in.h> 34#endif 35#ifdef HAVE_NETDB_H 36#include <netdb.h> 37#endif 38#ifdef HAVE_ARPA_INET_H 39#include <arpa/inet.h> 40#endif 41#ifdef __VMS 42#include <in.h> 43#include <inet.h> 44#endif 45 46#include "urldata.h" 47#include "sendf.h" 48#include "hostip.h" 49#include "hash.h" 50#include "share.h" 51#include "url.h" 52/* The last 3 #include files should be in this order */ 53#include "curl_printf.h" 54#include "curl_memory.h" 55#include "memdebug.h" 56 57/* 58 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've 59 * been set and returns TRUE if they are OK. 60 */ 61bool Curl_ipvalid(struct Curl_easy *data, struct connectdata *conn) 62{ 63 (void)data; 64 if(conn->ip_version == CURL_IPRESOLVE_V6) 65 /* An IPv6 address was requested and we can't get/use one */ 66 return FALSE; 67 68 return TRUE; /* OK, proceed */ 69} 70 71#ifdef CURLRES_SYNCH 72 73/* 74 * Curl_getaddrinfo() - the IPv4 synchronous version. 75 * 76 * The original code to this function was from the Dancer source code, written 77 * by Bjorn Reese, it has since been patched and modified considerably. 78 * 79 * gethostbyname_r() is the thread-safe version of the gethostbyname() 80 * function. When we build for plain IPv4, we attempt to use this 81 * function. There are _three_ different gethostbyname_r() versions, and we 82 * detect which one this platform supports in the configure script and set up 83 * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or 84 * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME 85 * has the corresponding rules. This is primarily on *nix. Note that some unix 86 * flavours have thread-safe versions of the plain gethostbyname() etc. 87 * 88 */ 89struct Curl_addrinfo *Curl_getaddrinfo(struct Curl_easy *data, 90 const char *hostname, 91 int port, 92 int *waitp) 93{ 94 struct Curl_addrinfo *ai = NULL; 95 96#ifdef CURL_DISABLE_VERBOSE_STRINGS 97 (void)data; 98#endif 99 100 *waitp = 0; /* synchronous response only */ 101 102 ai = Curl_ipv4_resolve_r(hostname, port); 103 if(!ai) 104 infof(data, "Curl_ipv4_resolve_r failed for %s", hostname); 105 106 return ai; 107} 108#endif /* CURLRES_SYNCH */ 109#endif /* CURLRES_IPV4 */ 110 111#if defined(CURLRES_IPV4) && \ 112 !defined(CURLRES_ARES) && !defined(CURLRES_AMIGA) 113 114/* 115 * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. 116 * 117 * This is used for both synchronous and asynchronous resolver builds, 118 * implying that only threadsafe code and function calls may be used. 119 * 120 */ 121struct Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, 122 int port) 123{ 124#if !(defined(HAVE_GETADDRINFO) && defined(HAVE_GETADDRINFO_THREADSAFE)) && \ 125 defined(HAVE_GETHOSTBYNAME_R_3) 126 int res; 127#endif 128 struct Curl_addrinfo *ai = NULL; 129 struct hostent *h = NULL; 130 struct hostent *buf = NULL; 131 132#if defined(HAVE_GETADDRINFO) && defined(HAVE_GETADDRINFO_THREADSAFE) 133 struct addrinfo hints; 134 char sbuf[12]; 135 char *sbufptr = NULL; 136 137 memset(&hints, 0, sizeof(hints)); 138 hints.ai_family = PF_INET; 139 hints.ai_socktype = SOCK_STREAM; 140 if(port) { 141 msnprintf(sbuf, sizeof(sbuf), "%d", port); 142 sbufptr = sbuf; 143 } 144 145 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); 146 147#elif defined(HAVE_GETHOSTBYNAME_R) 148 /* 149 * gethostbyname_r() is the preferred resolve function for many platforms. 150 * Since there are three different versions of it, the following code is 151 * somewhat #ifdef-ridden. 152 */ 153 int h_errnop; 154 155 buf = calloc(1, CURL_HOSTENT_SIZE); 156 if(!buf) 157 return NULL; /* major failure */ 158 /* 159 * The clearing of the buffer is a workaround for a gethostbyname_r bug in 160 * qnx nto and it is also _required_ for some of these functions on some 161 * platforms. 162 */ 163 164#if defined(HAVE_GETHOSTBYNAME_R_5) 165 /* Solaris, IRIX and more */ 166 h = gethostbyname_r(hostname, 167 (struct hostent *)buf, 168 (char *)buf + sizeof(struct hostent), 169 CURL_HOSTENT_SIZE - sizeof(struct hostent), 170 &h_errnop); 171 172 /* If the buffer is too small, it returns NULL and sets errno to 173 * ERANGE. The errno is thread safe if this is compiled with 174 * -D_REENTRANT as then the 'errno' variable is a macro defined to get 175 * used properly for threads. 176 */ 177 178 if(h) { 179 ; 180 } 181 else 182#elif defined(HAVE_GETHOSTBYNAME_R_6) 183 /* Linux */ 184 185 (void)gethostbyname_r(hostname, 186 (struct hostent *)buf, 187 (char *)buf + sizeof(struct hostent), 188 CURL_HOSTENT_SIZE - sizeof(struct hostent), 189 &h, /* DIFFERENCE */ 190 &h_errnop); 191 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a 192 * sudden this function returns EAGAIN if the given buffer size is too 193 * small. Previous versions are known to return ERANGE for the same 194 * problem. 195 * 196 * This wouldn't be such a big problem if older versions wouldn't 197 * sometimes return EAGAIN on a common failure case. Alas, we can't 198 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of 199 * glibc. 200 * 201 * For now, we do that and thus we may call the function repeatedly and 202 * fail for older glibc versions that return EAGAIN, until we run out of 203 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). 204 * 205 * If anyone has a better fix, please tell us! 206 * 207 * ------------------------------------------------------------------- 208 * 209 * On October 23rd 2003, Dan C dug up more details on the mysteries of 210 * gethostbyname_r() in glibc: 211 * 212 * In glibc 2.2.5 the interface is different (this has also been 213 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't 214 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 215 * (shipped/upgraded by Redhat 7.2) don't show this behavior! 216 * 217 * In this "buggy" version, the return code is -1 on error and 'errno' 218 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a 219 * thread-safe variable. 220 */ 221 222 if(!h) /* failure */ 223#elif defined(HAVE_GETHOSTBYNAME_R_3) 224 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ 225 226 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of 227 * the plain fact that it does not return unique full buffers on each 228 * call, but instead several of the pointers in the hostent structs will 229 * point to the same actual data! This have the unfortunate down-side that 230 * our caching system breaks down horribly. Luckily for us though, AIX 4.3 231 * and more recent versions have a "completely thread-safe"[*] libc where 232 * all the data is stored in thread-specific memory areas making calls to 233 * the plain old gethostbyname() work fine even for multi-threaded 234 * programs. 235 * 236 * This AIX 4.3 or later detection is all made in the configure script. 237 * 238 * Troels Walsted Hansen helped us work this out on March 3rd, 2003. 239 * 240 * [*] = much later we've found out that it isn't at all "completely 241 * thread-safe", but at least the gethostbyname() function is. 242 */ 243 244 if(CURL_HOSTENT_SIZE >= 245 (sizeof(struct hostent) + sizeof(struct hostent_data))) { 246 247 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version 248 * that should work! September 20: Richard Prescott worked on the buffer 249 * size dilemma. 250 */ 251 252 res = gethostbyname_r(hostname, 253 (struct hostent *)buf, 254 (struct hostent_data *)((char *)buf + 255 sizeof(struct hostent))); 256 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ 257 } 258 else 259 res = -1; /* failure, too smallish buffer size */ 260 261 if(!res) { /* success */ 262 263 h = buf; /* result expected in h */ 264 265 /* This is the worst kind of the different gethostbyname_r() interfaces. 266 * Since we don't know how big buffer this particular lookup required, 267 * we can't realloc down the huge alloc without doing closer analysis of 268 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every 269 * name lookup. Fixing this would require an extra malloc() and then 270 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new 271 * memory area to the actually used amount. 272 */ 273 } 274 else 275#endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ 276 { 277 h = NULL; /* set return code to NULL */ 278 free(buf); 279 } 280#else /* (HAVE_GETADDRINFO && HAVE_GETADDRINFO_THREADSAFE) || 281 HAVE_GETHOSTBYNAME_R */ 282 /* 283 * Here is code for platforms that don't have a thread safe 284 * getaddrinfo() nor gethostbyname_r() function or for which 285 * gethostbyname() is the preferred one. 286 */ 287 h = gethostbyname((void *)hostname); 288#endif /* (HAVE_GETADDRINFO && HAVE_GETADDRINFO_THREADSAFE) || 289 HAVE_GETHOSTBYNAME_R */ 290 291 if(h) { 292 ai = Curl_he2ai(h, port); 293 294 if(buf) /* used a *_r() function */ 295 free(buf); 296 } 297 298 return ai; 299} 300#endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) && 301 !defined(CURLRES_AMIGA) */ 302