1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2019, 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
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 */
65bool 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 */
92Curl_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 */
123Curl_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#ifdef ENABLE_IPV6
135 {
136 struct in6_addr in6;
137 /* check if this is an IPv6 address string */
138 if(Curl_inet_pton(AF_INET6, hostname, &in6) > 0)
139 /* This is an IPv6 address literal */
140 return Curl_ip2addr(AF_INET6, &in6, hostname, port);
141 }
142#endif /* ENABLE_IPV6 */
143
144 if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
145 /* This is a dotted IP address 123.123.123.123-style */
146 return Curl_ip2addr(AF_INET, &in, hostname, port);
147
148#if defined(HAVE_GETADDRINFO_THREADSAFE)
149 else {
150 struct addrinfo hints;
151 char sbuf[12];
152 char *sbufptr = NULL;
153
154 memset(&hints, 0, sizeof(hints));
155 hints.ai_family = PF_INET;
156 hints.ai_socktype = SOCK_STREAM;
157 if(port) {
158 msnprintf(sbuf, sizeof(sbuf), "%d", port);
159 sbufptr = sbuf;
160 }
161
162 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai);
163
164#elif defined(HAVE_GETHOSTBYNAME_R)
165 /*
166 * gethostbyname_r() is the preferred resolve function for many platforms.
167 * Since there are three different versions of it, the following code is
168 * somewhat #ifdef-ridden.
169 */
170 else {
171 int h_errnop;
172
173 buf = calloc(1, CURL_HOSTENT_SIZE);
174 if(!buf)
175 return NULL; /* major failure */
176 /*
177 * The clearing of the buffer is a workaround for a gethostbyname_r bug in
178 * qnx nto and it is also _required_ for some of these functions on some
179 * platforms.
180 */
181
182#if defined(HAVE_GETHOSTBYNAME_R_5)
183 /* Solaris, IRIX and more */
184 h = gethostbyname_r(hostname,
185 (struct hostent *)buf,
186 (char *)buf + sizeof(struct hostent),
187 CURL_HOSTENT_SIZE - sizeof(struct hostent),
188 &h_errnop);
189
190 /* If the buffer is too small, it returns NULL and sets errno to
191 * ERANGE. The errno is thread safe if this is compiled with
192 * -D_REENTRANT as then the 'errno' variable is a macro defined to get
193 * used properly for threads.
194 */
195
196 if(h) {
197 ;
198 }
199 else
200#elif defined(HAVE_GETHOSTBYNAME_R_6)
201 /* Linux */
202
203 (void)gethostbyname_r(hostname,
204 (struct hostent *)buf,
205 (char *)buf + sizeof(struct hostent),
206 CURL_HOSTENT_SIZE - sizeof(struct hostent),
207 &h, /* DIFFERENCE */
208 &h_errnop);
209 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a
210 * sudden this function returns EAGAIN if the given buffer size is too
211 * small. Previous versions are known to return ERANGE for the same
212 * problem.
213 *
214 * This wouldn't be such a big problem if older versions wouldn't
215 * sometimes return EAGAIN on a common failure case. Alas, we can't
216 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of
217 * glibc.
218 *
219 * For now, we do that and thus we may call the function repeatedly and
220 * fail for older glibc versions that return EAGAIN, until we run out of
221 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE).
222 *
223 * If anyone has a better fix, please tell us!
224 *
225 * -------------------------------------------------------------------
226 *
227 * On October 23rd 2003, Dan C dug up more details on the mysteries of
228 * gethostbyname_r() in glibc:
229 *
230 * In glibc 2.2.5 the interface is different (this has also been
231 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't
232 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32
233 * (shipped/upgraded by Redhat 7.2) don't show this behavior!
234 *
235 * In this "buggy" version, the return code is -1 on error and 'errno'
236 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a
237 * thread-safe variable.
238 */
239
240 if(!h) /* failure */
241#elif defined(HAVE_GETHOSTBYNAME_R_3)
242 /* AIX, Digital Unix/Tru64, HPUX 10, more? */
243
244 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of
245 * the plain fact that it does not return unique full buffers on each
246 * call, but instead several of the pointers in the hostent structs will
247 * point to the same actual data! This have the unfortunate down-side that
248 * our caching system breaks down horribly. Luckily for us though, AIX 4.3
249 * and more recent versions have a "completely thread-safe"[*] libc where
250 * all the data is stored in thread-specific memory areas making calls to
251 * the plain old gethostbyname() work fine even for multi-threaded
252 * programs.
253 *
254 * This AIX 4.3 or later detection is all made in the configure script.
255 *
256 * Troels Walsted Hansen helped us work this out on March 3rd, 2003.
257 *
258 * [*] = much later we've found out that it isn't at all "completely
259 * thread-safe", but at least the gethostbyname() function is.
260 */
261
262 if(CURL_HOSTENT_SIZE >=
263 (sizeof(struct hostent) + sizeof(struct hostent_data))) {
264
265 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version
266 * that should work! September 20: Richard Prescott worked on the buffer
267 * size dilemma.
268 */
269
270 res = gethostbyname_r(hostname,
271 (struct hostent *)buf,
272 (struct hostent_data *)((char *)buf +
273 sizeof(struct hostent)));
274 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */
275 }
276 else
277 res = -1; /* failure, too smallish buffer size */
278
279 if(!res) { /* success */
280
281 h = buf; /* result expected in h */
282
283 /* This is the worst kind of the different gethostbyname_r() interfaces.
284 * Since we don't know how big buffer this particular lookup required,
285 * we can't realloc down the huge alloc without doing closer analysis of
286 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every
287 * name lookup. Fixing this would require an extra malloc() and then
288 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new
289 * memory area to the actually used amount.
290 */
291 }
292 else
293#endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */
294 {
295 h = NULL; /* set return code to NULL */
296 free(buf);
297 }
298#else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
299 /*
300 * Here is code for platforms that don't have a thread safe
301 * getaddrinfo() nor gethostbyname_r() function or for which
302 * gethostbyname() is the preferred one.
303 */
304 else {
305 h = gethostbyname((void *)hostname);
306#endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
307 }
308
309 if(h) {
310 ai = Curl_he2ai(h, port);
311
312 if(buf) /* used a *_r() function */
313 free(buf);
314 }
315
316 return ai;
317}
318#endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */
319