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