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freebsd-nq/lib/libc/net/name6.c
Yoshinobu Inoue e6f35403c1 Change getaddrinfo() resolve order 
from
  all AAAA trial, then all A trial
to
  try AAAA and A for each trial

TODO: more fix for the case where IPv4 mapped IPv6 addr is disabled

Reviewed by: ume
2000-04-20 03:31:40 +00:00

1569 lines
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/*
* 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.
*
* $FreeBSD$
*/
/* $Id: name6.c,v 1.9 1999/10/29 03:04:26 itojun Exp $ */
/*
* Atsushi Onoe <onoe@sm.sony.co.jp>
*/
/*
* TODO for thread safe
* use mutex for _hostconf, _hostconf_init.
* rewrite resolvers to be thread safe
*/
#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 <unistd.h>
#ifndef _PATH_HOSTS
#define _PATH_HOSTS "/etc/hosts"
#endif
#ifndef MAXALIASES
#define MAXALIASES 10
#endif
#ifndef MAXADDRS
#define MAXADDRS 20
#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
};
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 struct hostent *_files_ghbyname(const char *name, int af, int *errp);
static struct hostent *_files_ghbyaddr(const void *addr, int addrlen, int af, int *errp);
static void _files_shent(int stayopen);
static void _files_ehent(void);
static struct hostent *_nis_ghbyname(const char *name, int af, int *errp);
static struct hostent *_nis_ghbyaddr(const void *addr, int addrlen, int af, int *errp);
static struct hostent *_dns_ghbyname(const char *name, int af, int *errp);
static struct hostent *_dns_ghbyaddr(const void *addr, int addrlen, int af, int *errp);
static void _dns_shent(int stayopen);
static void _dns_ehent(void);
#ifdef ICMPNL
static struct hostent *_icmp_ghbyaddr(const void *addr, int addrlen, int af, int *errp);
#endif /* ICMPNL */
/*
* Select order host function.
*/
#define MAXHOSTCONF 4
#ifndef HOSTCONF
# define HOSTCONF "/etc/host.conf"
#endif /* !HOSTCONF */
struct _hostconf {
struct hostent *(*byname)(const char *name, int af, int *errp);
struct hostent *(*byaddr)(const void *addr, int addrlen, int af, int *errp);
};
/* default order */
static struct _hostconf _hostconf[MAXHOSTCONF] = {
{ _dns_ghbyname, _dns_ghbyaddr },
{ _files_ghbyname, _files_ghbyaddr },
#ifdef ICMPNL
{ NULL, _icmp_ghbyaddr },
#endif /* ICMPNL */
};
static int _hostconf_init_done;
static void _hostconf_init(void);
/*
* Initialize hostconf structure.
*/
static void
_hostconf_init(void)
{
FILE *fp;
int n;
char *p, *line;
char buf[BUFSIZ];
_hostconf_init_done = 1;
n = 0;
p = HOSTCONF;
if ((fp = fopen(p, "r")) == NULL)
return;
while (n < MAXHOSTCONF && fgets(buf, sizeof(buf), fp)) {
line = buf;
if ((p = _hgetword(&line)) == NULL)
continue;
do {
if (strcmp(p, "hosts") == 0
|| strcmp(p, "local") == 0
|| strcmp(p, "file") == 0
|| strcmp(p, "files") == 0) {
_hostconf[n].byname = _files_ghbyname;
_hostconf[n].byaddr = _files_ghbyaddr;
n++;
}
else if (strcmp(p, "dns") == 0
|| strcmp(p, "bind") == 0) {
_hostconf[n].byname = _dns_ghbyname;
_hostconf[n].byaddr = _dns_ghbyaddr;
n++;
}
else if (strcmp(p, "nis") == 0) {
_hostconf[n].byname = _nis_ghbyname;
_hostconf[n].byaddr = _nis_ghbyaddr;
n++;
}
#ifdef ICMPNL
else if (strcmp(p, "icmp") == 0) {
_hostconf[n].byname = NULL;
_hostconf[n].byaddr = _icmp_ghbyaddr;
n++;
}
#endif /* ICMPNL */
} while ((p = _hgetword(&line)) != NULL);
}
fclose(fp);
if (n < 0) {
/* no keyword found. do not change default configuration */
return;
}
for (; n < MAXHOSTCONF; n++) {
_hostconf[n].byname = NULL;
_hostconf[n].byaddr = NULL;
}
}
/*
* 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, getipnodebyadr, freehostent
*/
static struct hostent *
_ghbyname(const char *name, int af, int flags, int *errp)
{
struct hostent *hp;
int i;
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);
}
}
for (i = 0; i < MAXHOSTCONF; i++) {
if (_hostconf[i].byname
&& (hp = (*_hostconf[i].byname)(name, af, errp))
!= NULL)
return hp;
}
return 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);
}
if (!_hostconf_init_done)
_hostconf_init();
*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 i;
#ifdef INET6
struct in6_addr addrbuf;
#else
struct in_addr addrbuf;
#endif
*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;
}
if (!_hostconf_init_done)
_hostconf_init();
for (i = 0; i < MAXHOSTCONF; i++) {
if (_hostconf[i].byaddr
&& (hp = (*_hostconf[i].byaddr)(src, len, af, errp)) != NULL)
return hp;
}
return 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 && *hp->h_name != '\0')
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 */
size = ALIGN(size);
al_off = size;
size += sizeof(char *) * (nalias + 1);
addrsize = ALIGN(hp->h_length);
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 && *hp->h_name != '\0') {
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);
hp->h_aliases = aliases;
nalias = 0;
for (i = 1; i <= 2; i++) {
if ((pp = HP(i)->h_aliases) == NULL)
continue;
for (; nalias < MAXALIASES && *pp != NULL; pp++) {
/* check duplicates */
for (j = 0; j < nalias; j++)
if (strcasecmp(*pp, aliases[j]) == 0)
break;
if (j == nalias)
aliases[nalias++] = *pp;
}
}
aliases[nalias] = NULL;
#ifdef INET6
if (hp1->h_length != hp2->h_length) {
hp->h_addrtype = AF_INET6;
hp->h_length = sizeof(struct in6_addr);
} else {
#endif
hp->h_addrtype = hp1->h_addrtype;
hp->h_length = hp1->h_length;
#ifdef INET6
}
#endif
hp->h_addr_list = addrs;
naddr = 0;
for (i = 1; i <= 2; i++) {
if ((pp = HP(i)->h_addr_list) == NULL)
continue;
if (HP(i)->h_length == hp->h_length) {
while (naddr < MAXADDRS && *pp != NULL)
addrs[naddr++] = *pp++;
} else {
/* copy IPv4 addr as mapped IPv6 addr */
while (naddr < MAXADDRS && *pp != NULL) {
MAPADDR(&addrbuf[naddr], *pp++);
addrs[naddr] = (char *)&addrbuf[naddr];
naddr++;
}
}
}
addrs[naddr] = NULL;
hp = _hpcopy(hp, errp);
freehostent(hp1);
freehostent(hp2);
return hp;
}
/*
* _hpmapv6: convert IPv4 hostent into IPv4-mapped IPv6 addresses
*/
#ifdef INET6
static struct hostent *
_hpmapv6(struct hostent *hp, int *errp)
{
struct hostent *hp6;
if (hp == NULL)
return NULL;
if (hp->h_addrtype == AF_INET6)
return hp;
/* make dummy hostent to convert IPv6 address */
if ((hp6 = (struct hostent *)malloc(sizeof(struct hostent))) == NULL) {
*errp = TRY_AGAIN;
return NULL;
}
hp6->h_name = NULL;
hp6->h_aliases = NULL;
hp6->h_addrtype = AF_INET6;
hp6->h_length = sizeof(struct in6_addr);
hp6->h_addr_list = NULL;
return _hpmerge(hp6, hp, errp);
}
#endif
/*
* _hpsort: sort address by sortlist
*/
static struct hostent *
_hpsort(struct hostent *hp)
{
int i, j, n;
u_char *ap, *sp, *mp, **pp;
char t;
char order[MAXADDRS];
int nsort = _res.nsort;
if (hp == NULL || hp->h_addr_list[1] == NULL || nsort == 0)
return hp;
for (i = 0; (ap = (u_char *)hp->h_addr_list[i]); i++) {
for (j = 0; j < nsort; j++) {
#ifdef INET6
if (_res_ext.sort_list[j].af != hp->h_addrtype)
continue;
sp = (u_char *)&_res_ext.sort_list[j].addr;
mp = (u_char *)&_res_ext.sort_list[j].mask;
#else
sp = (u_char *)&_res.sort_list[j].addr;
mp = (u_char *)&_res.sort_list[j].mask;
#endif
for (n = 0; n < hp->h_length; n++) {
if ((ap[n] & mp[n]) != sp[n])
break;
}
if (n == hp->h_length)
break;
}
order[i] = j;
}
n = i;
pp = (u_char **)hp->h_addr_list;
for (i = 0; i < n - 1; i++) {
for (j = i + 1; j < n; j++) {
if (order[i] > order[j]) {
ap = pp[i];
pp[i] = pp[j];
pp[j] = ap;
t = order[i];
order[i] = order[j];
order[j] = t;
}
}
}
return hp;
}
static char *
_hgetword(char **pp)
{
char c, *p, *ret;
const char *sp;
static const char sep[] = "# \t\n";
ret = NULL;
for (p = *pp; (c = *p) != '\0'; p++) {
for (sp = sep; *sp != '\0'; sp++) {
if (c == *sp)
break;
}
if (c == '#')
p[1] = '\0'; /* ignore rest of line */
if (ret == NULL) {
if (*sp == '\0')
ret = p;
} else {
if (*sp != '\0') {
*p++ = '\0';
break;
}
}
}
*pp = p;
if (ret == NULL || *ret == '\0')
return NULL;
return ret;
}
/*
* FILES (/etc/hosts)
*/
static FILE *
_files_open(int *errp)
{
FILE *fp;
fp = fopen(_PATH_HOSTS, "r");
if (fp == NULL)
*errp = NO_RECOVERY;
return fp;
}
static struct hostent *
_files_ghbyname(const char *name, int af, int *errp)
{
int match, nalias;
char *p, *line, *addrstr, *cname;
FILE *fp;
struct hostent *rethp, *hp, hpbuf;
char *aliases[MAXALIASES + 1], *addrs[2];
union inx_addr addrbuf;
char buf[BUFSIZ];
int af0 = af;
if ((fp = _files_open(errp)) == NULL)
return NULL;
rethp = hp = NULL;
while (fgets(buf, sizeof(buf), fp)) {
line = buf;
if ((addrstr = _hgetword(&line)) == NULL
|| (cname = _hgetword(&line)) == NULL)
continue;
match = (strcasecmp(cname, name) == 0);
nalias = 0;
while ((p = _hgetword(&line)) != NULL) {
if (!match)
match = (strcasecmp(p, name) == 0);
if (nalias < MAXALIASES)
aliases[nalias++] = p;
}
if (!match)
continue;
switch (af0) {
case AF_INET:
if (inet_aton(addrstr, (struct in_addr *)&addrbuf)
!= 1) {
*errp = NO_DATA; /* name found */
continue;
}
af = af0;
break;
#ifdef INET6
case AF_INET6:
if (inet_pton(af, addrstr, &addrbuf) != 1) {
*errp = NO_DATA; /* name found */
continue;
}
af = af0;
break;
#endif
case AF_UNSPEC:
if (inet_aton(addrstr, (struct in_addr *)&addrbuf)
== 1) {
af = AF_INET;
break;
}
#ifdef INET6
if (inet_pton(AF_INET6, addrstr, &addrbuf) == 1) {
af = AF_INET6;
break;
}
#endif
*errp = NO_DATA; /* name found */
continue;
/* NOTREACHED */
}
hp = &hpbuf;
hp->h_name = cname;
hp->h_aliases = aliases;
aliases[nalias] = NULL;
hp->h_addrtype = af;
hp->h_length = ADDRLEN(af);
hp->h_addr_list = addrs;
addrs[0] = (char *)&addrbuf;
addrs[1] = NULL;
hp = _hpcopy(hp, errp);
rethp = _hpmerge(rethp, hp, errp);
}
fclose(fp);
return rethp;
}
static struct hostent *
_files_ghbyaddr(const void *addr, int addrlen, int af, int *errp)
{
int nalias;
char *p, *line;
FILE *fp;
struct hostent *hp, hpbuf;
char *aliases[MAXALIASES + 1], *addrs[2];
union inx_addr addrbuf;
char buf[BUFSIZ];
if ((fp = _files_open(errp)) == NULL)
return NULL;
hp = NULL;
while (fgets(buf, sizeof(buf), fp)) {
line = buf;
if ((p = _hgetword(&line)) == NULL
|| (af == AF_INET
? inet_aton(p, (struct in_addr *)&addrbuf)
: inet_pton(af, p, &addrbuf)) != 1
|| memcmp(addr, &addrbuf, addrlen) != 0
|| (p = _hgetword(&line)) == NULL)
continue;
hp = &hpbuf;
hp->h_name = p;
hp->h_aliases = aliases;
nalias = 0;
while ((p = _hgetword(&line)) != NULL) {
if (nalias < MAXALIASES)
aliases[nalias++] = p;
}
aliases[nalias] = NULL;
hp->h_addrtype = af;
hp->h_length = addrlen;
hp->h_addr_list = addrs;
addrs[0] = (char *)&addrbuf;
addrs[1] = NULL;
hp = _hpcopy(hp, errp);
break;
}
fclose(fp);
return hp;
}
/*
* NIS
*
* XXX actually a hack, these are INET4 specific.
*/
static struct hostent *
_nis_ghbyname(const char *name, int af, int *errp)
{
struct hostent *hp = NULL;
if (af == AF_UNSPEC)
af = AF_INET;
if (af == AF_INET) {
hp = _gethostbynisname(name, af);
if (hp != NULL)
hp = _hpcopy(hp, errp);
}
return (hp);
}
static struct hostent *
_nis_ghbyaddr(const void *addr, int addrlen, int af, int *errp)
{
struct hostent *hp = NULL;
if (af == AF_INET) {
hp = _gethostbynisaddr(addr, addrlen, af);
if (hp != NULL)
hp = _hpcopy(hp, errp);
}
return (hp);
}
#ifdef DEBUG
#define DNS_ASSERT(X) if (!(X)) { fprintf(stderr, "ASSFAIL: %s %d: %s\n", __FILE__, __LINE__, #X); goto badanswer; }
#else
#define DNS_ASSERT(X) if (!(X)) { goto badanswer; }
#endif
struct __res_type_list {
SLIST_ENTRY(__res_type_list) rtl_entry;
int rtl_type;
};
static struct hostent *
_gethpbyanswer(answer, anslen, qtype, errp)
const u_char *answer;
int anslen;
int qtype;
int *errp;
{
int n;
char tbuf[MAXDNAME+1];
HEADER *hp;
const u_char *cp, *eom;
int type, class, ancount, qdcount;
u_long ttl;
char hostbuf[BUFSIZ];
char *bp;
char *alist[MAXALIASES];
char *hlist[MAXADDRS];
struct hostent hbuf;
int buflen;
int na, nh;
hbuf.h_aliases = alist;
hbuf.h_addrtype =
#ifdef INET6
(qtype == T_AAAA) ? AF_INET6 :
#endif
AF_INET;
hbuf.h_length = ADDRLEN(hbuf.h_addrtype);
hbuf.h_addr_list = hlist;
na = nh = 0;
hp = (HEADER *)answer;
eom = answer + anslen;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
DNS_ASSERT(qdcount == 1);
cp = answer + sizeof(HEADER);
bp = hostbuf;
buflen = sizeof(hostbuf);
n = dn_expand(answer, eom, cp, bp, buflen);
DNS_ASSERT(n >= 0);
cp += n + QFIXEDSZ;
hbuf.h_name = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
while (ancount-- > 0 && cp < eom) {
n = dn_expand(answer, eom, cp, bp, buflen);
DNS_ASSERT(n >= 0);
cp += n; /* name */
type = _getshort(cp);
cp += 2; /* type */
class = _getshort(cp);
cp += 2; /* class */
ttl = _getlong(cp);
cp += 4; /* ttl */
n = _getshort(cp);
cp += 2; /* len */
DNS_ASSERT(class == C_IN);
switch (type) {
case T_CNAME:
if (na >= MAXALIASES-1) {
cp += n;
break;
}
n = dn_expand(answer, eom, cp, tbuf, sizeof(tbuf));
DNS_ASSERT(n >= 0);
cp += n;
/* alias */
alist[na++] = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
/* canon */
n = strlen(tbuf) + 1;
DNS_ASSERT(n < buflen);
strcpy(bp, tbuf);
hbuf.h_name = bp;
bp += n;
buflen -= n;
break;
case T_A:
#ifdef INET6
case T_AAAA:
#endif
DNS_ASSERT(type == qtype);
bp = (char *)ALIGN(bp);
DNS_ASSERT(n == hbuf.h_length);
DNS_ASSERT(n < buflen);
if (nh < MAXADDRS-1) {
hlist[nh++] = bp;
memcpy(bp, cp, n);
bp += n;
buflen -= n;
}
cp += n;
break;
default:
DNS_ASSERT(0);
cp += n;
break;
}
}
if (nh == 0) {
badanswer:
*errp = NO_RECOVERY;
return NULL;
}
alist[na] = NULL;
hlist[nh] = NULL;
return _hpcopy(&hbuf, errp);
}
/* res_search() variant with multiple query support. */
static struct hostent *
_res_search_multi(name, rtl, errp)
const char *name; /* domain name */
struct __res_type_list *rtl; /* list of query types */
int *errp;
{
u_char answer[BUFSIZ]; /* buffer to put answer */
const char *cp, * const *domain;
struct hostent *hp0 = NULL, *hp;
u_int dots;
int trailing_dot, ret, saved_herrno;
int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
struct __res_type_list *rtl0 = rtl;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
*errp = NETDB_INTERNAL;
return (NULL);
}
dots = 0;
for (cp = name; *cp; cp++)
dots += (*cp == '.');
trailing_dot = 0;
if (cp > name && *--cp == '.')
trailing_dot++;
/* If there aren't any dots, it could be a user-level alias */
if (!dots && (cp = hostalias(name)) != NULL) {
for(rtl = rtl0; rtl != NULL;
rtl = SLIST_NEXT(rtl, rtl_entry)) {
ret = res_query(cp, C_IN, rtl->rtl_type, answer,
sizeof(answer));
if (ret > 0) {
hp = _gethpbyanswer(answer, ret, rtl->rtl_type,
errp);
hp0 = _hpmerge(hp0, hp, errp);
}
}
return (hp0);
}
/*
* If there are dots in the name already, let's just give it a try
* 'as is'. The threshold can be set with the "ndots" option.
*/
saved_herrno = -1;
if (dots >= _res.ndots) {
for(rtl = rtl0; rtl != NULL;
rtl = SLIST_NEXT(rtl, rtl_entry)) {
ret = res_querydomain(name, NULL, C_IN, rtl->rtl_type,
answer, sizeof(answer));
if (ret > 0) {
hp = _gethpbyanswer(answer, ret, rtl->rtl_type,
errp);
hp0 = _hpmerge(hp0, hp, errp);
}
}
if (hp0 != NULL)
return (hp0);
saved_herrno = *errp;
tried_as_is++;
}
/*
* We do at least one level of search if
* - there is no dot and RES_DEFNAME is set, or
* - there is at least one dot, there is no trailing dot,
* and RES_DNSRCH is set.
*/
if ((!dots && (_res.options & RES_DEFNAMES)) ||
(dots && !trailing_dot && (_res.options & RES_DNSRCH))) {
int done = 0;
for (domain = (const char * const *)_res.dnsrch;
*domain && !done;
domain++) {
for(rtl = rtl0; rtl != NULL;
rtl = SLIST_NEXT(rtl, rtl_entry)) {
ret = res_querydomain(name, *domain, C_IN,
rtl->rtl_type,
answer, sizeof(answer));
if (ret > 0) {
hp = _gethpbyanswer(answer, ret,
rtl->rtl_type,
errp);
hp0 = _hpmerge(hp0, hp, errp);
}
}
if (hp0 != NULL)
return (hp0);
/*
* If no server present, give up.
* If name isn't found in this domain,
* keep trying higher domains in the search list
* (if that's enabled).
* On a NO_DATA error, keep trying, otherwise
* a wildcard entry of another type could keep us
* from finding this entry higher in the domain.
* If we get some other error (negative answer or
* server failure), then stop searching up,
* but try the input name below in case it's
* fully-qualified.
*/
if (errno == ECONNREFUSED) {
*errp = TRY_AGAIN;
return (NULL);
}
switch (*errp) {
case NO_DATA:
got_nodata++;
/* FALLTHROUGH */
case HOST_NOT_FOUND:
/* keep trying */
break;
case TRY_AGAIN:
if (((HEADER *)answer)->rcode == SERVFAIL) {
/* try next search element, if any */
got_servfail++;
break;
}
/* FALLTHROUGH */
default:
/* anything else implies that we're done */
done++;
}
/* if we got here for some reason other than DNSRCH,
* we only wanted one iteration of the loop, so stop.
*/
if (!(_res.options & RES_DNSRCH))
done++;
}
}
/*
* If we have not already tried the name "as is", do that now.
* note that we do this regardless of how many dots were in the
* name or whether it ends with a dot unless NOTLDQUERY is set.
*/
if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
for(rtl = rtl0; rtl != NULL;
rtl = SLIST_NEXT(rtl, rtl_entry)) {
ret = res_querydomain(name, NULL, C_IN, rtl->rtl_type,
answer, sizeof(answer));
if (ret > 0) {
hp = _gethpbyanswer(answer, ret, rtl->rtl_type,
errp);
hp0 = _hpmerge(hp0, hp, errp);
}
}
if (hp0 != NULL)
return (hp0);
}
/* if we got here, we didn't satisfy the search.
* if we did an initial full query, return that query's h_errno
* (note that we wouldn't be here if that query had succeeded).
* else if we ever got a nodata, send that back as the reason.
* else send back meaningless h_errno, that being the one from
* the last DNSRCH we did.
*/
if (saved_herrno != -1)
*errp = saved_herrno;
else if (got_nodata)
*errp = NO_DATA;
else if (got_servfail)
*errp = TRY_AGAIN;
return (NULL);
}
static struct hostent *
_dns_ghbyname(const char *name, int af, int *errp)
{
struct __res_type_list *rtl, rtl4;
#ifdef INET6
struct __res_type_list rtl6;
#endif
#ifdef INET6
switch (af) {
case AF_UNSPEC:
SLIST_NEXT(&rtl4, rtl_entry) = NULL; rtl4.rtl_type = T_A;
SLIST_NEXT(&rtl6, rtl_entry) = &rtl4; rtl6.rtl_type = T_AAAA;
rtl = &rtl6;
break;
case AF_INET6:
SLIST_NEXT(&rtl6, rtl_entry) = NULL; rtl6.rtl_type = T_AAAA;
rtl = &rtl6;
break;
case AF_INET:
SLIST_NEXT(&rtl4, rtl_entry) = NULL; rtl4.rtl_type = T_A;
rtl = &rtl4;
break;
}
#else
SLIST_NEXT(&rtl4, rtl_entry) = NULL; rtl4.rtl_type = T_A;
rtl = &rtl4;
#endif
return(_res_search_multi(name, rtl, errp));
}
static struct hostent *
_dns_ghbyaddr(const void *addr, int addrlen, int af, int *errp)
{
int n;
u_char answer[BUFSIZ];
HEADER *hp;
u_char c, *cp, *eom;
int type, class, ancount, qdcount;
u_long ttl;
char hostbuf[BUFSIZ];
char *bp;
char *alist[MAXALIASES];
char *hlist[2];
struct hostent hbuf;
int buflen;
int na;
#ifdef INET6
static const char hex[] = "0123456789abcdef";
#endif
#ifdef INET6
/* XXX */
if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL((struct in6_addr *)addr))
return NULL;
#endif
if ((_res.options & RES_INIT) == 0) {
if (res_init() < 0) {
*errp = h_errno;
return NULL;
}
}
hbuf.h_name = NULL;
hbuf.h_aliases = alist;
hbuf.h_addrtype = af;
hbuf.h_length = addrlen;
hbuf.h_addr_list = hlist;
hlist[0] = (char *)addr;
hlist[1] = NULL;
na = 0;
n = 0;
bp = hostbuf;
cp = (u_char *)addr+addrlen-1;
switch (af) {
#ifdef INET6
case AF_INET6:
for (; n < addrlen; n++, cp--) {
c = *cp;
*bp++ = hex[c & 0xf];
*bp++ = '.';
*bp++ = hex[c >> 4];
*bp++ = '.';
}
strcpy(bp, "ip6.int");
break;
#endif
default:
for (; n < addrlen; n++, cp--) {
c = *cp;
if (c >= 100)
*bp++ = '0' + c / 100;
if (c >= 10)
*bp++ = '0' + (c % 100) / 10;
*bp++ = '0' + c % 10;
*bp++ = '.';
}
strcpy(bp, "in-addr.arpa");
break;
}
n = res_query(hostbuf, C_IN, T_PTR, answer, sizeof(answer));
if (n < 0) {
*errp = h_errno;
return NULL;
}
hp = (HEADER *)answer;
eom = answer + n;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
DNS_ASSERT(qdcount == 1);
cp = answer + sizeof(HEADER);
bp = hostbuf;
buflen = sizeof(hostbuf);
n = dn_expand(answer, eom, cp, bp, buflen);
DNS_ASSERT(n >= 0);
cp += n + QFIXEDSZ;
while (ancount-- > 0 && cp < eom) {
n = dn_expand(answer, eom, cp, bp, buflen);
DNS_ASSERT(n >= 0);
cp += n; /* name */
type = _getshort(cp);
cp += 2; /* type */
class = _getshort(cp);
cp += 2; /* class */
ttl = _getlong(cp);
cp += 4; /* ttl */
n = _getshort(cp);
cp += 2; /* len */
DNS_ASSERT(class == C_IN);
switch (type) {
case T_PTR:
n = dn_expand(answer, eom, cp, bp, buflen);
DNS_ASSERT(n >= 0);
cp += n;
if (na >= MAXALIASES-1)
break;
if (hbuf.h_name == NULL)
hbuf.h_name = bp;
else
alist[na++] = bp;
n = strlen(bp) + 1;
bp += n;
buflen -= n;
break;
case T_CNAME:
cp += n;
break;
default:
badanswer:
*errp = NO_RECOVERY;
return NULL;
}
}
if (hbuf.h_name == NULL) {
*errp = h_errno;
return NULL;
}
alist[na] = NULL;
return _hpcopy(&hbuf, errp);
}
#ifdef ICMPNL
/*
* experimental:
* draft-ietf-ipngwg-icmp-namelookups-02.txt
* ifindex is assumed to be encoded in addr.
*/
#include <sys/uio.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
struct _icmp_host_cache {
struct _icmp_host_cache *hc_next;
int hc_ifindex;
struct in6_addr hc_addr;
char *hc_name;
};
static char *
_icmp_fqdn_query(const struct in6_addr *addr, int ifindex)
{
int s;
struct icmp6_filter filter;
struct msghdr msg;
struct cmsghdr *cmsg;
struct in6_pktinfo *pkt;
char cbuf[256];
char buf[1024];
int cc;
struct icmp6_fqdn_query *fq;
struct icmp6_fqdn_reply *fr;
struct _icmp_host_cache *hc;
struct sockaddr_in6 sin6;
struct iovec iov;
fd_set s_fds, fds;
struct timeval tout;
int len;
char *name;
static int pid;
static struct _icmp_host_cache *hc_head;
for (hc = hc_head; hc; hc = hc->hc_next) {
if (hc->hc_ifindex == ifindex
&& IN6_ARE_ADDR_EQUAL(&hc->hc_addr, addr))
return hc->hc_name;
}
if (pid == 0)
pid = getpid();
ICMP6_FILTER_SETBLOCKALL(&filter);
ICMP6_FILTER_SETPASS(ICMP6_FQDN_REPLY, &filter);
FD_ZERO(&s_fds);
tout.tv_sec = 0;
tout.tv_usec = 200000; /*XXX: 200ms*/
fq = (struct icmp6_fqdn_query *)buf;
fq->icmp6_fqdn_type = ICMP6_FQDN_QUERY;
fq->icmp6_fqdn_code = 0;
fq->icmp6_fqdn_cksum = 0;
fq->icmp6_fqdn_id = (u_short)pid;
fq->icmp6_fqdn_unused = 0;
fq->icmp6_fqdn_cookie[0] = 0;
fq->icmp6_fqdn_cookie[1] = 0;
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = *addr;
memset(&msg, 0, sizeof(msg));
msg.msg_name = (caddr_t)&sin6;
msg.msg_namelen = sizeof(sin6);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
iov.iov_base = (caddr_t)buf;
iov.iov_len = sizeof(struct icmp6_fqdn_query);
if (ifindex) {
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
pkt = (struct in6_pktinfo *)&cmsg[1];
memset(&pkt->ipi6_addr, 0, sizeof(struct in6_addr));
pkt->ipi6_ifindex = ifindex;
cmsg = CMSG_NXTHDR(&msg, cmsg);
msg.msg_controllen = (char *)cmsg - cbuf;
}
if ((s = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0)
return NULL;
(void)setsockopt(s, IPPROTO_ICMPV6, ICMP6_FILTER,
(char *)&filter, sizeof(filter));
cc = sendmsg(s, &msg, 0);
if (cc < 0) {
_close(s);
return NULL;
}
FD_SET(s, &s_fds);
for (;;) {
fds = s_fds;
if (select(s + 1, &fds, NULL, NULL, &tout) <= 0) {
_close(s);
return NULL;
}
len = sizeof(sin6);
cc = recvfrom(s, buf, sizeof(buf), 0,
(struct sockaddr *)&sin6, &len);
if (cc <= 0) {
_close(s);
return NULL;
}
if (cc < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr))
continue;
if (!IN6_ARE_ADDR_EQUAL(addr, &sin6.sin6_addr))
continue;
fr = (struct icmp6_fqdn_reply *)(buf + sizeof(struct ip6_hdr));
if (fr->icmp6_fqdn_type == ICMP6_FQDN_REPLY)
break;
}
_close(s);
if (fr->icmp6_fqdn_cookie[1] != 0) {
/* rfc1788 type */
name = buf + sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr) + 4;
len = (buf + cc) - name;
} else {
len = fr->icmp6_fqdn_namelen;
name = fr->icmp6_fqdn_name;
}
if (len <= 0)
return NULL;
name[len] = 0;
if ((hc = (struct _icmp_host_cache *)malloc(sizeof(*hc))) == NULL)
return NULL;
/* XXX: limit number of cached entries */
hc->hc_ifindex = ifindex;
hc->hc_addr = *addr;
hc->hc_name = strdup(name);
hc->hc_next = hc_head;
hc_head = hc;
return hc->hc_name;
}
static struct hostent *
_icmp_ghbyaddr(const void *addr, int addrlen, int af, int *errp)
{
char *hname;
int ifindex;
struct in6_addr addr6;
if (af != AF_INET6) {
/*
* Note: rfc1788 defines Who Are You for IPv4,
* but no one implements it.
*/
return NULL;
}
memcpy(&addr6, addr, addrlen);
ifindex = (addr6.s6_addr[2] << 8) | addr6.s6_addr[3];
addr6.s6_addr[2] = addr6.s6_addr[3] = 0;
if (!IN6_IS_ADDR_LINKLOCAL(&addr6))
return NULL; /*XXX*/
if ((hname = _icmp_fqdn_query(&addr6, ifindex)) == NULL)
return NULL;
return _hpaddr(af, hname, &addr6, errp);
}
#endif /* ICMPNL */
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