name6.c

Newlib 嵌入式 C库 标准实现代码

/*	$KAME: name6.c,v 1.25 2000/06/26 16:44:40 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * ++Copyright++ 1985, 1988, 1993
 * -
 * Copyright (c) 1985, 1988, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */

/*
 *	Atsushi Onoe <[e-mail]>
 */

/*
 * TODO for thread safe
 *	use mutex for _hostconf, _hostconf_init.
 *	rewrite resolvers to be thread safe
 */

#include <sys/cdefs.h>
#include <sys/types.h>
#include <machine/endian.h>
#include <sys/types.h>
#include <unistd.h>

#include "namespace.h"
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <netinet/in.h>

#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <nsswitch.h>
#include <unistd.h>
#include "un-namespace.h"

#ifndef _PATH_HOSTS
#define	_PATH_HOSTS	"/etc/hosts"
#endif

#ifndef MAXALIASES
#define	MAXALIASES	35
#endif
#ifndef	MAXADDRS
#define	MAXADDRS	2
#endif
#ifndef MAXDNAME
#define	MAXDNAME	1025
#endif

#ifdef INET6
#define	ADDRLEN(af)	((af) == AF_INET6 ? sizeof(struct in6_addr) : \
					    sizeof(struct in_addr))
#else
#define	ADDRLEN(af)	sizeof(struct in_addr)
#endif

#define	MAPADDR(ab, ina) \
do {									\
	memcpy(&(ab)->map_inaddr, ina, sizeof(struct in_addr));		\
	memset((ab)->map_zero, 0, sizeof((ab)->map_zero));		\
	memset((ab)->map_one, 0xff, sizeof((ab)->map_one));		\
} while (0)
#define	MAPADDRENABLED(flags) \
	(((flags) & AI_V4MAPPED) || \
	 (((flags) & AI_V4MAPPED_CFG) && _mapped_addr_enabled()))

union inx_addr {
	struct in_addr	in_addr;
#ifdef INET6
	struct in6_addr	in6_addr;
#endif
	struct {
		u_char	mau_zero[10];
		u_char	mau_one[2];
		struct in_addr mau_inaddr;
	}		map_addr_un;
#define	map_zero	map_addr_un.mau_zero
#define	map_one		map_addr_un.mau_one
#define	map_inaddr	map_addr_un.mau_inaddr
};

u_int16_t _getshort(const u_char *src);

static struct	 hostent *_hpcopy(struct hostent *hp, int *errp);
static struct	 hostent *_hpaddr(int af, const char *name, void *addr, int *errp);
static struct	 hostent *_hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp);
#ifdef INET6
static struct	 hostent *_hpmapv6(struct hostent *hp, int *errp);
#endif
static struct	 hostent *_hpsort(struct hostent *hp);
static struct	 hostent *_ghbyname(const char *name, int af, int flags, int *errp);
static char	*_hgetword(char **pp);
static int	 _mapped_addr_enabled(void);

static FILE	*_files_open(int *errp);
static int	 _files_ghbyname(void *, void *, va_list);
static int	 _files_ghbyaddr(void *, void *, va_list);
#if 0 // keep gcc happy
static void	 _files_shent(int stayopen);
static void	 _files_ehent(void);
#endif
#ifdef YP
static int	 _nis_ghbyname(void *, void *, va_list);
static int	 _nis_ghbyaddr(void *, void *, va_list);
#endif
static int	 _dns_ghbyname(void *, void *, va_list);
static int	 _dns_ghbyaddr(void *, void *, va_list);
#if 0 // keep gcc happy
static void	 _dns_shent(int stayopen);
static void	 _dns_ehent(void);
#endif

#ifdef ICMPNL
static int	 _icmp_ghbyaddr(void *, void *, va_list);
#endif /* ICMPNL */

/* Host lookup order if nsswitch.conf is broken or nonexistant */
static const ns_src default_src[] = { 
	{ NSSRC_FILES, NS_SUCCESS },
	{ NSSRC_DNS, NS_SUCCESS },
#ifdef ICMPNL
#define NSSRC_ICMP "icmp"
	{ NSSRC_ICMP, NS_SUCCESS },
#endif
	{ 0 }
};

/*
 * Check if kernel supports mapped address.
 *	implementation dependent
 */
#ifdef __KAME__
#include <sys/sysctl.h>
#endif /* __KAME__ */

static int
_mapped_addr_enabled(void)
{
	/* implementation dependent check */
#if defined(__KAME__) && defined(IPV6CTL_MAPPED_ADDR)
	int mib[4];
	size_t len;
	int val;

	mib[0] = CTL_NET;
	mib[1] = PF_INET6;
	mib[2] = IPPROTO_IPV6;
	mib[3] = IPV6CTL_MAPPED_ADDR;
	len = sizeof(val);
	if (__sysctl(mib, 4, &val, &len, 0, 0) == 0 && val != 0)
		return 1;
#endif /* __KAME__ && IPV6CTL_MAPPED_ADDR */
	return 0;
}

/*
 * Functions defined in RFC2553
 *	getipnodebyname, getipnodebyaddr, freehostent
 */

static struct hostent *
_ghbyname(const char *name, int af, int flags, int *errp)
{
	struct hostent *hp;
	int rval;
	
	static const ns_dtab dtab[] = {
		NS_FILES_CB(_files_ghbyname, NULL)
		{ NSSRC_DNS, _dns_ghbyname, NULL },
		NS_NIS_CB(_nis_ghbyname, NULL)
		{ 0 }
	};

	if (flags & AI_ADDRCONFIG) {
		int s;

		/*
		 * TODO:
		 * Note that implementation dependent test for address
		 * configuration should be done everytime called
		 * (or apropriate interval),
		 * because addresses will be dynamically assigned or deleted.
		 */
		if (af == AF_UNSPEC) {
			if ((s = socket(AF_INET6, SOCK_DGRAM, 0)) < 0)
				af = AF_INET;
			else {
				close(s);
				if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
					af = AF_INET6;
				else
				close(s);
			}

		}
		if (af != AF_UNSPEC) {
			if ((s = socket(af, SOCK_DGRAM, 0)) < 0)
				return NULL;
			close(s);
		}
	}

	rval = nsdispatch(&hp, dtab, NSDB_HOSTS, "ghbyname", default_src,
			  name, af, errp);
	return (rval == NS_SUCCESS) ? hp : NULL;
}

/* getipnodebyname() internal routine for multiple query(PF_UNSPEC) support. */
struct hostent *
_getipnodebyname_multi(const char *name, int af, int flags, int *errp)
{
	struct hostent *hp;
	union inx_addr addrbuf;

	/* XXX: PF_UNSPEC is only supposed to be passed from getaddrinfo() */
	if (af != AF_INET
#ifdef INET6
	    && af != AF_INET6
#endif
	    && af != PF_UNSPEC
		)
	{
		*errp = NO_RECOVERY;
		return NULL;
	}

#ifdef INET6
	/* special case for literal address */
	if (inet_pton(AF_INET6, name, &addrbuf) == 1) {
		if (af != AF_INET6) {
			*errp = HOST_NOT_FOUND;
			return NULL;
		}
		return _hpaddr(af, name, &addrbuf, errp);
	}
#endif
	if (inet_aton(name, (struct in_addr *)&addrbuf) == 1) {
		if (af != AF_INET) {
			if (MAPADDRENABLED(flags)) {
				MAPADDR(&addrbuf, &addrbuf.in_addr);
			} else {
				*errp = HOST_NOT_FOUND;
				return NULL;
			}
		}
		return _hpaddr(af, name, &addrbuf, errp);
	}

	*errp = HOST_NOT_FOUND;
	hp = _ghbyname(name, af, flags, errp);

#ifdef INET6
	if (af == AF_INET6
	&&  ((flags & AI_ALL) || hp == NULL)
	&&  (MAPADDRENABLED(flags))) {
		struct hostent *hp2 = _ghbyname(name, AF_INET, flags, errp);
		if (hp == NULL)
			hp = _hpmapv6(hp2, errp);
		else {
			if (hp2 && strcmp(hp->h_name, hp2->h_name) != 0) {
				freehostent(hp2);
				hp2 = NULL;
			}
			hp = _hpmerge(hp, hp2, errp);
		}
	}
#endif
	return _hpsort(hp);
}

struct hostent *
getipnodebyname(const char *name, int af, int flags, int *errp)
{
	if (af != AF_INET
#ifdef INET6
	    && af != AF_INET6
#endif
		)
	{
		*errp = NO_RECOVERY;
		return NULL;
	}
	return(_getipnodebyname_multi(name, af ,flags, errp));
}

struct hostent *
getipnodebyaddr(const void *src, size_t len, int af, int *errp)
{
	struct hostent *hp;
	int rval;
#ifdef INET6
	struct in6_addr addrbuf;
#else
	struct in_addr addrbuf;
#endif

	static const ns_dtab dtab[] = {
		NS_FILES_CB(_files_ghbyaddr, NULL)
		{ NSSRC_DNS, _dns_ghbyaddr, NULL },
		NS_NIS_CB(_nis_ghbyaddr, NULL)
#ifdef ICMPNL
		{ NSSRC_ICMP, _icmp_ghbyaddr, NULL },
#endif
		{ 0 }
	};

	*errp = HOST_NOT_FOUND;

	switch (af) {
	case AF_INET:
		if (len != sizeof(struct in_addr)) {
			*errp = NO_RECOVERY;
			return NULL;
		}
		if ((long)src & ~(sizeof(struct in_addr) - 1)) {
			memcpy(&addrbuf, src, len);
			src = &addrbuf;
		}
		if (((struct in_addr *)src)->s_addr == 0)
			return NULL;
		break;
#ifdef INET6
	case AF_INET6:
		if (len != sizeof(struct in6_addr)) {
			*errp = NO_RECOVERY;
			return NULL;
		}
		if ((long)src & ~(sizeof(struct in6_addr) / 2 - 1)) {	/*XXX*/
			memcpy(&addrbuf, src, len);
			src = &addrbuf;
		}
		if (IN6_IS_ADDR_UNSPECIFIED((struct in6_addr *)src))
			return NULL;
		if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)src)
		||  IN6_IS_ADDR_V4COMPAT((struct in6_addr *)src)) {
			src = (char *)src +
			    (sizeof(struct in6_addr) - sizeof(struct in_addr));
			af = AF_INET;
			len = sizeof(struct in_addr);
		}
		break;
#endif
	default:
		*errp = NO_RECOVERY;
		return NULL;
	}

	rval = nsdispatch(&hp, dtab, NSDB_HOSTS, "ghbyaddr", default_src,
			  src, len, af, errp);
	return (rval == NS_SUCCESS) ? hp : NULL;
}

void
freehostent(struct hostent *ptr)
{
	free(ptr);
}

#if 0

/* XXX: should be deprecated */
struct hostent *
getnodebyname(const char *name, int af, int flags)
{
	return getipnodebyname(name, af, flags, &h_errno);
}

#ifdef __warn_references
__warn_references(getnodebyname,
	"warning: getnodebyname() deprecated, "
	"should use getaddrinfo() or getipnodebyname()");
#endif

struct hostent *
getnodebyaddr(const void *src, size_t len, int af)
{
	return getipnodebyaddr(src, len, af, &h_errno);
}

#ifdef __warn_references
__warn_references(getnodebyaddr,
	"warning: getnodebyaddr() deprecated, "
	"should use getnameinfo() or getipnodebyaddr()");
#endif

#endif

/*
 * Private utility functions
 */

/*
 * _hpcopy: allocate and copy hostent structure
 */
static struct hostent *
_hpcopy(struct hostent *hp, int *errp)
{
	struct hostent *nhp;
	char *cp, **pp;
	int size, addrsize;
	int nalias = 0, naddr = 0;
	int al_off;
	int i;

	if (hp == NULL)
		return hp;

	/* count size to be allocated */
	size = sizeof(struct hostent);
	if (hp->h_name != NULL)
		size += strlen(hp->h_name) + 1;
	if ((pp = hp->h_aliases) != NULL) {
		for (i = 0; *pp != NULL; i++, pp++) {
			if (**pp != '\0') {
				size += strlen(*pp) + 1;
				nalias++;
			}
		}
	}
	/* adjust alignment */
#ifdef	ALIGN
	size = ALIGN(size);
#endif
	al_off = size;
	size += sizeof(char *) * (nalias + 1);
#ifdef ALIGN
	addrsize = ALIGN(hp->h_length);
#else
	addrsize = hp->h_length;
#endif
        
	if ((pp = hp->h_addr_list) != NULL) {
		while (*pp++ != NULL)
			naddr++;
	}
	size += addrsize * naddr;
	size += sizeof(char *) * (naddr + 1);

	/* copy */
	if ((nhp = (struct hostent *)malloc(size)) == NULL) {
		*errp = TRY_AGAIN;
		return NULL;
	}
	cp = (char *)&nhp[1];
	if (hp->h_name != NULL) {
		nhp->h_name = cp;
		strcpy(cp, hp->h_name);
		cp += strlen(cp) + 1;
	} else
		nhp->h_name = NULL;
	nhp->h_aliases = (char **)((char *)nhp + al_off);
	if ((pp = hp->h_aliases) != NULL) {
		for (i = 0; *pp != NULL; pp++) {
			if (**pp != '\0') {
				nhp->h_aliases[i++] = cp;
				strcpy(cp, *pp);
				cp += strlen(cp) + 1;
			}
		}
	}
	nhp->h_aliases[nalias] = NULL;
	cp = (char *)&nhp->h_aliases[nalias + 1];
	nhp->h_addrtype = hp->h_addrtype;
	nhp->h_length = hp->h_length;
	nhp->h_addr_list = (char **)cp;
	if ((pp = hp->h_addr_list) != NULL) {
		cp = (char *)&nhp->h_addr_list[naddr + 1];
		for (i = 0; *pp != NULL; pp++) {
			nhp->h_addr_list[i++] = cp;
			memcpy(cp, *pp, hp->h_length);
			cp += addrsize;
		}
	}
	nhp->h_addr_list[naddr] = NULL;
	return nhp;
}

/*
 * _hpaddr: construct hostent structure with one address
 */
static struct hostent *
_hpaddr(int af, const char *name, void *addr, int *errp)
{
	struct hostent *hp, hpbuf;
	char *addrs[2];

	hp = &hpbuf;
	hp->h_name = (char *)name;
	hp->h_aliases = NULL;
	hp->h_addrtype = af;
	hp->h_length = ADDRLEN(af);
	hp->h_addr_list = addrs;
	addrs[0] = (char *)addr;
	addrs[1] = NULL;
	return _hpcopy(hp, errp);
}

/*
 * _hpmerge: merge 2 hostent structure, arguments will be freed
 */
static struct hostent *
_hpmerge(struct hostent *hp1, struct hostent *hp2, int *errp)
{
	int i, j;
	int naddr, nalias;
	char **pp;
	struct hostent *hp, hpbuf;
	char *aliases[MAXALIASES + 1], *addrs[MAXADDRS + 1];
	union inx_addr addrbuf[MAXADDRS];

	if (hp1 == NULL)
		return hp2;
	if (hp2 == NULL)
		return hp1;

#define	HP(i)	(i == 1 ? hp1 : hp2)
	hp = &hpbuf;
	hp->h_name = (hp1->h_name != NULL ? hp1->h_name : hp2->h_name);