summaryrefslogtreecommitdiffstats
path: root/src/port/getaddrinfo.c
blob: 3284c6eb52ab1ada00759888fb00d25feef13dcc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
/*-------------------------------------------------------------------------
 *
 * getaddrinfo.c
 *	  Support getaddrinfo() on platforms that don't have it.
 *
 * We also supply getnameinfo() here, assuming that the platform will have
 * it if and only if it has getaddrinfo().  If this proves false on some
 * platform, we'll need to split this file and provide a separate configure
 * test for getnameinfo().
 *
 * Windows may or may not have these routines, so we handle Windows specially
 * by dynamically checking for their existence.  If they already exist, we
 * use the Windows native routines, but if not, we use our own.
 *
 *
 * Copyright (c) 2003-2022, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *	  src/port/getaddrinfo.c
 *
 *-------------------------------------------------------------------------
 */

/* This is intended to be used in both frontend and backend, so use c.h */
#include "c.h"

#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "getaddrinfo.h"
#include "libpq/pqcomm.h"		/* needed for struct sockaddr_storage */
#include "port/pg_bswap.h"


#ifdef FRONTEND
static int	pqGethostbyname(const char *name,
							struct hostent *resultbuf,
							char *buffer, size_t buflen,
							struct hostent **result,
							int *herrno);
#endif

#ifdef WIN32
/*
 * The native routines may or may not exist on the Windows platform we are on,
 * so we dynamically look up the routines, and call them via function pointers.
 * Here we need to declare what the function pointers look like
 */
typedef int (__stdcall * getaddrinfo_ptr_t) (const char *nodename,
											 const char *servname,
											 const struct addrinfo *hints,
											 struct addrinfo **res);

typedef void (__stdcall * freeaddrinfo_ptr_t) (struct addrinfo *ai);

typedef int (__stdcall * getnameinfo_ptr_t) (const struct sockaddr *sa,
											 int salen,
											 char *node, int nodelen,
											 char *service, int servicelen,
											 int flags);

/* static pointers to the native routines, so we only do the lookup once. */
static getaddrinfo_ptr_t getaddrinfo_ptr = NULL;
static freeaddrinfo_ptr_t freeaddrinfo_ptr = NULL;
static getnameinfo_ptr_t getnameinfo_ptr = NULL;


static bool
haveNativeWindowsIPv6routines(void)
{
	void	   *hLibrary = NULL;
	static bool alreadyLookedForIpv6routines = false;

	if (alreadyLookedForIpv6routines)
		return (getaddrinfo_ptr != NULL);

	/*
	 * For Windows XP and later versions, the IPv6 routines are present in the
	 * WinSock 2 library (ws2_32.dll).
	 */
	hLibrary = LoadLibraryA("ws2_32");

	/* If hLibrary is null, we couldn't find a dll with functions */
	if (hLibrary != NULL)
	{
		/* We found a dll, so now get the addresses of the routines */

		getaddrinfo_ptr = (getaddrinfo_ptr_t) (pg_funcptr_t) GetProcAddress(hLibrary,
																			"getaddrinfo");
		freeaddrinfo_ptr = (freeaddrinfo_ptr_t) (pg_funcptr_t) GetProcAddress(hLibrary,
																			  "freeaddrinfo");
		getnameinfo_ptr = (getnameinfo_ptr_t) (pg_funcptr_t) GetProcAddress(hLibrary,
																			"getnameinfo");

		/*
		 * If any one of the routines is missing, let's play it safe and
		 * ignore them all
		 */
		if (getaddrinfo_ptr == NULL ||
			freeaddrinfo_ptr == NULL ||
			getnameinfo_ptr == NULL)
		{
			FreeLibrary(hLibrary);
			hLibrary = NULL;
			getaddrinfo_ptr = NULL;
			freeaddrinfo_ptr = NULL;
			getnameinfo_ptr = NULL;
		}
	}

	alreadyLookedForIpv6routines = true;
	return (getaddrinfo_ptr != NULL);
}
#endif


/*
 * get address info for ipv4 sockets.
 *
 *	Bugs:	- only one addrinfo is set even though hintp is NULL or
 *		  ai_socktype is 0
 *		- AI_CANONNAME is not supported.
 *		- servname can only be a number, not text.
 */
int
getaddrinfo(const char *node, const char *service,
			const struct addrinfo *hintp,
			struct addrinfo **res)
{
	struct addrinfo *ai;
	struct sockaddr_in sin,
			   *psin;
	struct addrinfo hints;

#ifdef WIN32

	/*
	 * If Windows has native IPv6 support, use the native Windows routine.
	 * Otherwise, fall through and use our own code.
	 */
	if (haveNativeWindowsIPv6routines())
		return (*getaddrinfo_ptr) (node, service, hintp, res);
#endif

	if (hintp == NULL)
	{
		memset(&hints, 0, sizeof(hints));
		hints.ai_family = AF_INET;
		hints.ai_socktype = SOCK_STREAM;
	}
	else
		memcpy(&hints, hintp, sizeof(hints));

	if (hints.ai_family != AF_INET && hints.ai_family != AF_UNSPEC)
		return EAI_FAMILY;

	if (hints.ai_socktype == 0)
		hints.ai_socktype = SOCK_STREAM;

	if (!node && !service)
		return EAI_NONAME;

	memset(&sin, 0, sizeof(sin));

	sin.sin_family = AF_INET;

	if (node)
	{
		if (node[0] == '\0')
			sin.sin_addr.s_addr = pg_hton32(INADDR_ANY);
		else if (hints.ai_flags & AI_NUMERICHOST)
		{
			if (!inet_aton(node, &sin.sin_addr))
				return EAI_NONAME;
		}
		else
		{
			struct hostent *hp;

#ifdef FRONTEND
			struct hostent hpstr;
			char		buf[BUFSIZ];
			int			herrno = 0;

			pqGethostbyname(node, &hpstr, buf, sizeof(buf),
							&hp, &herrno);
#else
			hp = gethostbyname(node);
#endif
			if (hp == NULL)
			{
				switch (h_errno)
				{
					case HOST_NOT_FOUND:
					case NO_DATA:
						return EAI_NONAME;
					case TRY_AGAIN:
						return EAI_AGAIN;
					case NO_RECOVERY:
					default:
						return EAI_FAIL;
				}
			}
			if (hp->h_addrtype != AF_INET)
				return EAI_FAIL;

			memcpy(&(sin.sin_addr), hp->h_addr, hp->h_length);
		}
	}
	else
	{
		if (hints.ai_flags & AI_PASSIVE)
			sin.sin_addr.s_addr = pg_hton32(INADDR_ANY);
		else
			sin.sin_addr.s_addr = pg_hton32(INADDR_LOOPBACK);
	}

	if (service)
		sin.sin_port = pg_hton16((unsigned short) atoi(service));

#ifdef HAVE_STRUCT_SOCKADDR_STORAGE_SS_LEN
	sin.sin_len = sizeof(sin);
#endif

	ai = malloc(sizeof(*ai));
	if (!ai)
		return EAI_MEMORY;

	psin = malloc(sizeof(*psin));
	if (!psin)
	{
		free(ai);
		return EAI_MEMORY;
	}

	memcpy(psin, &sin, sizeof(*psin));

	ai->ai_flags = 0;
	ai->ai_family = AF_INET;
	ai->ai_socktype = hints.ai_socktype;
	ai->ai_protocol = hints.ai_protocol;
	ai->ai_addrlen = sizeof(*psin);
	ai->ai_addr = (struct sockaddr *) psin;
	ai->ai_canonname = NULL;
	ai->ai_next = NULL;

	*res = ai;

	return 0;
}


void
freeaddrinfo(struct addrinfo *res)
{
	if (res)
	{
#ifdef WIN32

		/*
		 * If Windows has native IPv6 support, use the native Windows routine.
		 * Otherwise, fall through and use our own code.
		 */
		if (haveNativeWindowsIPv6routines())
		{
			(*freeaddrinfo_ptr) (res);
			return;
		}
#endif

		if (res->ai_addr)
			free(res->ai_addr);
		free(res);
	}
}


const char *
gai_strerror(int errcode)
{
#ifdef HAVE_HSTRERROR
	int			hcode;

	switch (errcode)
	{
		case EAI_NONAME:
			hcode = HOST_NOT_FOUND;
			break;
		case EAI_AGAIN:
			hcode = TRY_AGAIN;
			break;
		case EAI_FAIL:
		default:
			hcode = NO_RECOVERY;
			break;
	}

	return hstrerror(hcode);
#else							/* !HAVE_HSTRERROR */

	switch (errcode)
	{
		case EAI_NONAME:
			return "Unknown host";
		case EAI_AGAIN:
			return "Host name lookup failure";
			/* Errors below are probably WIN32 only */
#ifdef EAI_BADFLAGS
		case EAI_BADFLAGS:
			return "Invalid argument";
#endif
#ifdef EAI_FAMILY
		case EAI_FAMILY:
			return "Address family not supported";
#endif
#ifdef EAI_MEMORY
		case EAI_MEMORY:
			return "Not enough memory";
#endif
#if defined(EAI_NODATA) && EAI_NODATA != EAI_NONAME /* MSVC/WIN64 duplicate */
		case EAI_NODATA:
			return "No host data of that type was found";
#endif
#ifdef EAI_SERVICE
		case EAI_SERVICE:
			return "Class type not found";
#endif
#ifdef EAI_SOCKTYPE
		case EAI_SOCKTYPE:
			return "Socket type not supported";
#endif
		default:
			return "Unknown server error";
	}
#endif							/* HAVE_HSTRERROR */
}

/*
 * Convert an ipv4 address to a hostname.
 *
 * Bugs:	- Only supports NI_NUMERICHOST and NI_NUMERICSERV behavior.
 *		  It will never resolve a hostname.
 *		- No IPv6 support.
 */
int
getnameinfo(const struct sockaddr *sa, int salen,
			char *node, int nodelen,
			char *service, int servicelen, int flags)
{
#ifdef WIN32

	/*
	 * If Windows has native IPv6 support, use the native Windows routine.
	 * Otherwise, fall through and use our own code.
	 */
	if (haveNativeWindowsIPv6routines())
		return (*getnameinfo_ptr) (sa, salen, node, nodelen,
								   service, servicelen, flags);
#endif

	/* Invalid arguments. */
	if (sa == NULL || (node == NULL && service == NULL))
		return EAI_FAIL;

#ifdef	HAVE_IPV6
	if (sa->sa_family == AF_INET6)
		return EAI_FAMILY;
#endif

	/* Unsupported flags. */
	if (flags & NI_NAMEREQD)
		return EAI_AGAIN;

	if (node)
	{
		if (sa->sa_family == AF_INET)
		{
			if (pg_inet_net_ntop(AF_INET,
								 &((struct sockaddr_in *) sa)->sin_addr,
								 sa->sa_family == AF_INET ? 32 : 128,
								 node, nodelen) == NULL)
				return EAI_MEMORY;
		}
		else
			return EAI_MEMORY;
	}

	if (service)
	{
		int			ret = -1;

		if (sa->sa_family == AF_INET)
		{
			ret = snprintf(service, servicelen, "%d",
						   pg_ntoh16(((struct sockaddr_in *) sa)->sin_port));
		}
		if (ret < 0 || ret >= servicelen)
			return EAI_MEMORY;
	}

	return 0;
}

/*
 * Wrapper around gethostbyname() or gethostbyname_r() to mimic
 * POSIX gethostbyname_r() behaviour, if it is not available or required.
 */
#ifdef FRONTEND
static int
pqGethostbyname(const char *name,
				struct hostent *resultbuf,
				char *buffer, size_t buflen,
				struct hostent **result,
				int *herrno)
{
#if defined(ENABLE_THREAD_SAFETY) && defined(HAVE_GETHOSTBYNAME_R)

	/*
	 * broken (well early POSIX draft) gethostbyname_r() which returns 'struct
	 * hostent *'
	 */
	*result = gethostbyname_r(name, resultbuf, buffer, buflen, herrno);
	return (*result == NULL) ? -1 : 0;
#else

	/* no gethostbyname_r(), just use gethostbyname() */
	*result = gethostbyname(name);

	if (*result != NULL)
		*herrno = h_errno;

	if (*result != NULL)
		return 0;
	else
		return -1;
#endif
}
#endif							/* FRONTEND */