/* $NetBSD: gethnamaddr.c,v 1.70 2006/03/22 00:03:51 christos Exp $ */
/*
* ++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. 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--
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "arpa_nameser.h"
#include "resolv_private.h"
#include "resolv_cache.h"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <stdio.h>
#include <strings.h>
#include <syslog.h>
#include <unistd.h>
#ifndef LOG_AUTH
# define LOG_AUTH 0
#endif
#define MULTI_PTRS_ARE_ALIASES 1 /* XXX - experimental */
#include "nsswitch.h"
#include <stdlib.h>
#include <string.h>
// This should be synchronized to ResponseCode.h
static const int DnsProxyQueryResult = 222;
static const char const AskedForGot[] =
"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
#define MAXPACKET (64*1024)
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
typedef union {
int32_t al;
char ac;
} align;
#ifdef DEBUG
static void dprintf(const char *, res_state, ...)
__attribute__((__format__(__printf__, 1, 3)));
#endif
static struct hostent *getanswer(const querybuf *, int, const char *, int,
res_state);
static void map_v4v6_address(const char *, char *);
static void map_v4v6_hostent(struct hostent *, char **, char *);
static void addrsort(char **, int, res_state);
static void _sethtent(int);
static void _endhtent(void);
static struct hostent *_gethtent(void);
void ht_sethostent(int);
void ht_endhostent(void);
struct hostent *ht_gethostbyname(char *);
struct hostent *ht_gethostbyaddr(const char *, int, int);
void dns_service(void);
#undef dn_skipname
int dn_skipname(const u_char *, const u_char *);
static int _gethtbyaddr(void *, void *, va_list);
static int _gethtbyname(void *, void *, va_list);
static struct hostent *_gethtbyname2(const char *, int);
static int _dns_gethtbyaddr(void *, void *, va_list);
static int _dns_gethtbyname(void *, void *, va_list);
static struct hostent *gethostbyname_internal(const char *, int, res_state, const char *, int);
static const ns_src default_dns_files[] = {
{ NSSRC_FILES, NS_SUCCESS },
{ NSSRC_DNS, NS_SUCCESS },
{ 0, 0 }
};
#ifdef DEBUG
static void
dprintf(const char *msg, res_state res, ...)
{
assert(msg != NULL);
if (res->options & RES_DEBUG) {
int save = errno;
va_list ap;
va_start (ap, res);
vprintf(msg, ap);
va_end (ap);
errno = save;
}
}
#else
# define dprintf(msg, res, num) ((void)0) /*nada*/
#endif
#define BOUNDED_INCR(x) \
do { \
cp += (x); \
if (cp > eom) { \
h_errno = NO_RECOVERY; \
return NULL; \
} \
} while (/*CONSTCOND*/0)
#define BOUNDS_CHECK(ptr, count) \
do { \
if ((ptr) + (count) > eom) { \
h_errno = NO_RECOVERY; \
return NULL; \
} \
} while (/*CONSTCOND*/0)
static struct hostent *
getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
res_state res)
{
const HEADER *hp;
const u_char *cp;
int n;
const u_char *eom, *erdata;
char *bp, **ap, **hap, *ep;
int type, class, ancount, qdcount;
int haveanswer, had_error;
int toobig = 0;
char tbuf[MAXDNAME];
const char *tname;
int (*name_ok)(const char *);
res_static rs = __res_get_static();
assert(answer != NULL);
assert(qname != NULL);
tname = qname;
rs->host.h_name = NULL;
eom = answer->buf + anslen;
switch (qtype) {
case T_A:
case T_AAAA:
name_ok = res_hnok;
break;
case T_PTR:
name_ok = res_dnok;
break;
default:
return NULL; /* XXX should be abort(); */
}
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
bp = rs->hostbuf;
ep = rs->hostbuf + sizeof rs->hostbuf;
cp = answer->buf;
BOUNDED_INCR(HFIXEDSZ);
if (qdcount != 1) {
h_errno = NO_RECOVERY;
return NULL;
}
n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
if ((n < 0) || !(*name_ok)(bp)) {
h_errno = NO_RECOVERY;
return NULL;
}
BOUNDED_INCR(n + QFIXEDSZ);
if (qtype == T_A || qtype == T_AAAA) {
/* res_send() has already verified that the query name is the
* same as the one we sent; this just gets the expanded name
* (i.e., with the succeeding search-domain tacked on).
*/
n = strlen(bp) + 1; /* for the \0 */
if (n >= MAXHOSTNAMELEN) {
h_errno = NO_RECOVERY;
return NULL;
}
rs->host.h_name = bp;
bp += n;
/* The qname can be abbreviated, but h_name is now absolute. */
qname = rs->host.h_name;
}
ap = rs->host_aliases;
*ap = NULL;
rs->host.h_aliases = rs->host_aliases;
hap = rs->h_addr_ptrs;
*hap = NULL;
rs->host.h_addr_list = rs->h_addr_ptrs;
haveanswer = 0;
had_error = 0;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
if ((n < 0) || !(*name_ok)(bp)) {
had_error++;
continue;
}
cp += n; /* name */
BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
type = _getshort(cp);
cp += INT16SZ; /* type */
class = _getshort(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = _getshort(cp);
cp += INT16SZ; /* len */
BOUNDS_CHECK(cp, n);
erdata = cp + n;
if (class != C_IN) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) {
if (ap >= &rs->host_aliases[MAXALIASES-1])
continue;
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if ((n < 0) || !(*name_ok)(tbuf)) {
had_error++;
continue;
}
cp += n;
if (cp != erdata) {
h_errno = NO_RECOVERY;
return NULL;
}
/* Store alias. */
*ap++ = bp;
n = strlen(bp) + 1; /* for the \0 */
if (n >= MAXHOSTNAMELEN) {
had_error++;
continue;
}
bp += n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > ep - bp || n >= MAXHOSTNAMELEN) {
had_error++;
continue;
}
strlcpy(bp, tbuf, (size_t)(ep - bp));
rs->host.h_name = bp;
bp += n;
continue;
}
if (qtype == T_PTR && type == T_CNAME) {
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if (n < 0 || !res_dnok(tbuf)) {
had_error++;
continue;
}
cp += n;
if (cp != erdata) {
h_errno = NO_RECOVERY;
return NULL;
}
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > ep - bp || n >= MAXHOSTNAMELEN) {
had_error++;
continue;
}
strlcpy(bp, tbuf, (size_t)(ep - bp));
tname = bp;
bp += n;
continue;
}
if (type != qtype) {
if (type != T_KEY && type != T_SIG)
syslog(LOG_NOTICE|LOG_AUTH,
"gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"",
qname, p_class(C_IN), p_type(qtype),
p_type(type));
cp += n;
continue; /* XXX - had_error++ ? */
}
switch (type) {
case T_PTR:
if (strcasecmp(tname, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, qname, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
n = dn_expand(answer->buf, eom, cp, bp, ep - bp);
if ((n < 0) || !res_hnok(bp)) {
had_error++;
break;
}
#if MULTI_PTRS_ARE_ALIASES
cp += n;
if (cp != erdata) {
h_errno = NO_RECOVERY;
return NULL;
}
if (!haveanswer)
rs->host.h_name = bp;
else if (ap < &rs->host_aliases[MAXALIASES-1])
*ap++ = bp;
else
n = -1;
if (n != -1) {
n = strlen(bp) + 1; /* for the \0 */
if (n >= MAXHOSTNAMELEN) {
had_error++;
break;
}
bp += n;
}
break;
#else
rs->host.h_name = bp;
if (res->options & RES_USE_INET6) {
n = strlen(bp) + 1; /* for the \0 */
if (n >= MAXHOSTNAMELEN) {
had_error++;
break;
}
bp += n;
map_v4v6_hostent(&rs->host, &bp, ep);
}
h_errno = NETDB_SUCCESS;
return &rs->host;
#endif
case T_A:
case T_AAAA:
if (strcasecmp(rs->host.h_name, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, rs->host.h_name, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
if (n != rs->host.h_length) {
cp += n;
continue;
}
if (type == T_AAAA) {
struct in6_addr in6;
memcpy(&in6, cp, IN6ADDRSZ);
if (IN6_IS_ADDR_V4MAPPED(&in6)) {
cp += n;
continue;
}
}
if (!haveanswer) {
int nn;
rs->host.h_name = bp;
nn = strlen(bp) + 1; /* for the \0 */
bp += nn;
}
bp += sizeof(align) -
(size_t)((u_long)bp % sizeof(align));
if (bp + n >= &rs->hostbuf[sizeof rs->hostbuf]) {
dprintf("size (%d) too big\n", res, n);
had_error++;
continue;
}
if (hap >= &rs->h_addr_ptrs[MAXADDRS-1]) {
if (!toobig++)
dprintf("Too many addresses (%d)\n",
res, MAXADDRS);
cp += n;
continue;
}
(void)memcpy(*hap++ = bp, cp, (size_t)n);
bp += n;
cp += n;
if (cp != erdata) {
h_errno = NO_RECOVERY;
return NULL;
}
break;
default:
abort();
}
if (!had_error)
haveanswer++;
}
if (haveanswer) {
*ap = NULL;
*hap = NULL;
/*
* Note: we sort even if host can take only one address
* in its return structures - should give it the "best"
* address in that case, not some random one
*/
if (res->nsort && haveanswer > 1 && qtype == T_A)
addrsort(rs->h_addr_ptrs, haveanswer, res);
if (!rs->host.h_name) {
n = strlen(qname) + 1; /* for the \0 */
if (n > ep - bp || n >= MAXHOSTNAMELEN)
goto no_recovery;
strlcpy(bp, qname, (size_t)(ep - bp));
rs->host.h_name = bp;
bp += n;
}
if (res->options & RES_USE_INET6)
map_v4v6_hostent(&rs->host, &bp, ep);
h_errno = NETDB_SUCCESS;
return &rs->host;
}
no_recovery:
h_errno = NO_RECOVERY;
return NULL;
}
int
gethostbyname_r(const char *name, struct hostent *hp, char *buf, size_t buflen,
struct hostent**result, int *errorp)
{
struct hostent *res;
res = gethostbyname(name);
*errorp = h_errno;
if (res == NULL) {
*result = NULL;
return -1;
}
memcpy(hp, res, sizeof *hp);
*result = hp;
return 0;
}
struct hostent *
gethostbyname(const char *name)
{
struct hostent *hp;
res_state res = __res_get_state();
if (res == NULL)
return NULL;
assert(name != NULL);
/* try IPv6 first - if that fails do IPv4 */
if (res->options & RES_USE_INET6) {
hp = gethostbyname_internal(name, AF_INET6, res, NULL, 0);
if (hp) {
__res_put_state(res);
return hp;
}
}
hp = gethostbyname_internal(name, AF_INET, res, NULL, 0);
__res_put_state(res);
return hp;
}
struct hostent *
gethostbyname2(const char *name, int af)
{
return android_gethostbynameforiface(name, af, NULL, 0);
}
struct hostent *
android_gethostbynameforiface(const char *name, int af, const char *iface, int mark)
{
struct hostent *hp;
res_state res = __res_get_state();
if (res == NULL)
return NULL;
hp = gethostbyname_internal(name, af, res, iface, mark);
__res_put_state(res);
return hp;
}
static FILE* android_open_proxy()
{
int sock;
const int one = 1;
struct sockaddr_un proxy_addr;
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
return NULL;
}
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
memset(&proxy_addr, 0, sizeof(proxy_addr));
proxy_addr.sun_family = AF_UNIX;
strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path));
if (TEMP_FAILURE_RETRY(connect(sock,
(const struct sockaddr*) &proxy_addr,
sizeof(proxy_addr))) != 0) {
close(sock);
return NULL;
}
return fdopen(sock, "r+");
}
static struct hostent *
android_read_hostent(FILE* proxy)
{
uint32_t size;
char buf[4];
if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) return NULL;
/* This is reading serialized data from system/netd/DnsProxyListener.cpp
* and changes here need to be matched there */
int result_code = strtol(buf, NULL, 10);
if (result_code != DnsProxyQueryResult) {
fread(&size, 1, sizeof(size), proxy);
return NULL;
}
if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
size = ntohl(size);
res_static rs = __res_get_static();
memset(&rs->host, 0, sizeof(rs->host));
char *ptr = rs->hostbuf;
if (fread(ptr, 1, size, proxy) != size) return NULL;
ptr += size;
rs->host.h_name = rs->hostbuf;
char **aliases = rs->host_aliases;
rs->host.h_aliases = rs->host_aliases;
while (1) {
if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
size = ntohl(size);
if (size == 0) {
*aliases = NULL;
break;
}
if (fread(ptr, 1, size, proxy) != size) return NULL;
*aliases++ = ptr;
ptr += size;
}
if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
rs->host.h_addrtype = ntohl(size);
if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
rs->host.h_length = ntohl(size);
char **addrs = rs->h_addr_ptrs;
rs->host.h_addr_list = rs->h_addr_ptrs;
while (1) {
if (fread(&size, 1, sizeof(size), proxy) != sizeof(size)) return NULL;
size = ntohl(size);
if (size == 0) {
*addrs = NULL;
break;
}
if (fread(ptr, 1, size, proxy) != size) return NULL;
*addrs++ = ptr;
ptr += size;
}
return &rs->host;
}
static struct hostent *
gethostbyname_internal_real(const char *name, int af, res_state res)
{
const char *cp;
char *bp, *ep;
int size;
struct hostent *hp;
res_static rs = __res_get_static();
static const ns_dtab dtab[] = {
NS_FILES_CB(_gethtbyname, NULL)
{ NSSRC_DNS, _dns_gethtbyname, NULL }, /* force -DHESIOD */
{ 0, 0, 0 }
};
assert(name != NULL);
switch (af) {
case AF_INET:
size = INADDRSZ;
break;
case AF_INET6:
size = IN6ADDRSZ;
break;
default:
h_errno = NETDB_INTERNAL;
errno = EAFNOSUPPORT;
return NULL;
}
rs->host.h_addrtype = af;
rs->host.h_length = size;
/*
* if there aren't any dots, it could be a user-level alias.
* this is also done in res_nquery() since we are not the only
* function that looks up host names.
*/
if (!strchr(name, '.') && (cp = __hostalias(name)))
name = cp;
/*
* disallow names consisting only of digits/dots, unless
* they end in a dot.
*/
if (isdigit((u_char) name[0]))
for (cp = name;; ++cp) {
if (!*cp) {
if (*--cp == '.')
break;
/*
* All-numeric, no dot at the end.
* Fake up a hostent as if we'd actually
* done a lookup.
*/
if (inet_pton(af, name,
(char *)(void *)rs->host_addr) <= 0) {
h_errno = HOST_NOT_FOUND;
return NULL;
}
strncpy(rs->hostbuf, name, MAXDNAME);
rs->hostbuf[MAXDNAME] = '\0';
bp = rs->hostbuf + MAXDNAME;
ep = rs->hostbuf + sizeof rs->hostbuf;
rs->host.h_name = rs->hostbuf;
rs->host.h_aliases = rs->host_aliases;
rs->host_aliases[0] = NULL;
rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
rs->h_addr_ptrs[1] = NULL;
rs->host.h_addr_list = rs->h_addr_ptrs;
if (res->options & RES_USE_INET6)
map_v4v6_hostent(&rs->host, &bp, ep);
h_errno = NETDB_SUCCESS;
return &rs->host;
}
if (!isdigit((u_char) *cp) && *cp != '.')
break;
}
if ((isxdigit((u_char) name[0]) && strchr(name, ':') != NULL) ||
name[0] == ':')
for (cp = name;; ++cp) {
if (!*cp) {
if (*--cp == '.')
break;
/*
* All-IPv6-legal, no dot at the end.
* Fake up a hostent as if we'd actually
* done a lookup.
*/
if (inet_pton(af, name,
(char *)(void *)rs->host_addr) <= 0) {
h_errno = HOST_NOT_FOUND;
return NULL;
}
strncpy(rs->hostbuf, name, MAXDNAME);
rs->hostbuf[MAXDNAME] = '\0';
bp = rs->hostbuf + MAXDNAME;
ep = rs->hostbuf + sizeof rs->hostbuf;
rs->host.h_name = rs->hostbuf;
rs->host.h_aliases = rs->host_aliases;
rs->host_aliases[0] = NULL;
rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
rs->h_addr_ptrs[1] = NULL;
rs->host.h_addr_list = rs->h_addr_ptrs;
h_errno = NETDB_SUCCESS;
return &rs->host;
}
if (!isxdigit((u_char) *cp) && *cp != ':' && *cp != '.')
break;
}
hp = NULL;
h_errno = NETDB_INTERNAL;
if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyname",
default_dns_files, name, strlen(name), af) != NS_SUCCESS) {
return NULL;
}
h_errno = NETDB_SUCCESS;
return hp;
}
// very similar in proxy-ness to android_getaddrinfo_proxy
static struct hostent *
gethostbyname_internal(const char *name, int af, res_state res, const char *iface, int mark)
{
const char *cache_mode = getenv("ANDROID_DNS_MODE");
FILE* proxy = NULL;
struct hostent *result = NULL;
if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) {
res_setiface(res, iface);
res_setmark(res, mark);
return gethostbyname_internal_real(name, af, res);
}
proxy = android_open_proxy();
if (proxy == NULL) goto exit;
/* This is writing to system/netd/DnsProxyListener.cpp and changes
* here need to be matched there */
if (fprintf(proxy, "gethostbyname %s %s %d",
iface == NULL ? "^" : iface,
name == NULL ? "^" : name,
af) < 0) {
goto exit;
}
if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
goto exit;
}
result = android_read_hostent(proxy);
exit:
if (proxy != NULL) {
fclose(proxy);
}
return result;
}
struct hostent *
android_gethostbyaddrforiface_proxy(const void *addr,
socklen_t len, int af, const char* iface, int mark)
{
struct hostent *result = NULL;
FILE* proxy = android_open_proxy();
if (proxy == NULL) goto exit;
char buf[INET6_ADDRSTRLEN]; //big enough for IPv4 and IPv6
const char * addrStr = inet_ntop(af, addr, buf, sizeof(buf));
if (addrStr == NULL) goto exit;
if (fprintf(proxy, "gethostbyaddr %s %d %d %s",
addrStr, len, af, iface == NULL ? "^" : iface) < 0) {
goto exit;
}
if (fputc(0, proxy) == EOF || fflush(proxy) != 0) {
goto exit;
}
result = android_read_hostent(proxy);
exit:
if (proxy != NULL) {
fclose(proxy);
}
return result;
}
struct hostent *
android_gethostbyaddrforiface_real(const void *addr,
socklen_t len, int af, const char* iface, int mark)
{
const u_char *uaddr = (const u_char *)addr;
socklen_t size;
struct hostent *hp;
static const ns_dtab dtab[] = {
NS_FILES_CB(_gethtbyaddr, NULL)
{ NSSRC_DNS, _dns_gethtbyaddr, NULL }, /* force -DHESIOD */
{ 0, 0, 0 }
};
assert(addr != NULL);
if (af == AF_INET6 && len == IN6ADDRSZ &&
(IN6_IS_ADDR_LINKLOCAL((const struct in6_addr *)(const void *)uaddr) ||
IN6_IS_ADDR_SITELOCAL((const struct in6_addr *)(const void *)uaddr))) {
h_errno = HOST_NOT_FOUND;
return NULL;
}
if (af == AF_INET6 && len == IN6ADDRSZ &&
(IN6_IS_ADDR_V4MAPPED((const struct in6_addr *)(const void *)uaddr) ||
IN6_IS_ADDR_V4COMPAT((const struct in6_addr *)(const void *)uaddr))) {
/* Unmap. */
addr += IN6ADDRSZ - INADDRSZ;
uaddr += IN6ADDRSZ - INADDRSZ;
af = AF_INET;
len = INADDRSZ;
}
switch (af) {
case AF_INET:
size = INADDRSZ;
break;
case AF_INET6:
size = IN6ADDRSZ;
break;
default:
errno = EAFNOSUPPORT;
h_errno = NETDB_INTERNAL;
return NULL;
}
if (size != len) {
errno = EINVAL;
h_errno = NETDB_INTERNAL;
return NULL;
}
hp = NULL;
h_errno = NETDB_INTERNAL;
if (nsdispatch(&hp, dtab, NSDB_HOSTS, "gethostbyaddr",
default_dns_files, uaddr, len, af, iface, mark) != NS_SUCCESS)
return NULL;
h_errno = NETDB_SUCCESS;
return hp;
}
struct hostent *
android_gethostbyaddrforiface(const void *addr, socklen_t len, int af, const char* iface, int mark)
{
const char *cache_mode = getenv("ANDROID_DNS_MODE");
if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
return android_gethostbyaddrforiface_proxy(addr, len, af, iface, mark);
} else {
return android_gethostbyaddrforiface_real(addr,len, af, iface, mark);
}
}
struct hostent *
gethostbyaddr(const void *addr, socklen_t len, int af)
{
return android_gethostbyaddrforiface(addr, len, af, NULL, 0);
}
static void
_sethtent(int f)
{
res_static rs = __res_get_static();
if (rs == NULL) return;
if (!rs->hostf)
rs->hostf = fopen(_PATH_HOSTS, "r" );
else
rewind(rs->hostf);
rs->stayopen = f;
}
static void
_endhtent(void)
{
res_static rs = __res_get_static();
if (rs == NULL) return;
if (rs->hostf && !rs->stayopen) {
(void) fclose(rs->hostf);
rs->hostf = NULL;
}
}
static struct hostent *
_gethtent(void)
{
char *p;
char *cp, **q;
int af, len;
res_static rs = __res_get_static();
if (!rs->hostf && !(rs->hostf = fopen(_PATH_HOSTS, "r" ))) {
h_errno = NETDB_INTERNAL;
return NULL;
}
again:
if (!(p = fgets(rs->hostbuf, sizeof rs->hostbuf, rs->hostf))) {
h_errno = HOST_NOT_FOUND;
return NULL;
}
if (*p == '#')
goto again;
if (!(cp = strpbrk(p, "#\n")))
goto again;
*cp = '\0';
if (!(cp = strpbrk(p, " \t")))
goto again;
*cp++ = '\0';
if (inet_pton(AF_INET6, p, (char *)(void *)rs->host_addr) > 0) {
af = AF_INET6;
len = IN6ADDRSZ;
} else if (inet_pton(AF_INET, p, (char *)(void *)rs->host_addr) > 0) {
res_state res = __res_get_state();
if (res == NULL)
return NULL;
if (res->options & RES_USE_INET6) {
map_v4v6_address((char *)(void *)rs->host_addr,
(char *)(void *)rs->host_addr);
af = AF_INET6;
len = IN6ADDRSZ;
} else {
af = AF_INET;
len = INADDRSZ;
}
__res_put_state(res);
} else {
goto again;
}
/* if this is not something we're looking for, skip it. */
if (rs->host.h_addrtype != 0 && rs->host.h_addrtype != af)
goto again;
if (rs->host.h_length != 0 && rs->host.h_length != len)
goto again;
rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
rs->h_addr_ptrs[1] = NULL;
rs->host.h_addr_list = rs->h_addr_ptrs;
rs->host.h_length = len;
rs->host.h_addrtype = af;
while (*cp == ' ' || *cp == '\t')
cp++;
rs->host.h_name = cp;
q = rs->host.h_aliases = rs->host_aliases;
if ((cp = strpbrk(cp, " \t")) != NULL)
*cp++ = '\0';
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (q < &rs->host_aliases[MAXALIASES - 1])
*q++ = cp;
if ((cp = strpbrk(cp, " \t")) != NULL)
*cp++ = '\0';
}
*q = NULL;
h_errno = NETDB_SUCCESS;
return &rs->host;
}
/*ARGSUSED*/
int
_gethtbyname(void *rv, void *cb_data, va_list ap)
{
struct hostent *hp;
const char *name;
int af;
assert(rv != NULL);
name = va_arg(ap, char *);
/* NOSTRICT skip len */(void)va_arg(ap, int);
af = va_arg(ap, int);
hp = NULL;
#if 0
{
res_state res = __res_get_state();
if (res == NULL)
return NS_NOTFOUND;
if (res->options & RES_USE_INET6)
hp = _gethtbyname2(name, AF_INET6);
if (hp==NULL)
hp = _gethtbyname2(name, AF_INET);
__res_put_state(res);
}
#else
hp = _gethtbyname2(name, af);
#endif
*((struct hostent **)rv) = hp;
if (hp == NULL) {
h_errno = HOST_NOT_FOUND;
return NS_NOTFOUND;
}
return NS_SUCCESS;
}
static struct hostent *
_gethtbyname2(const char *name, int af)
{
struct hostent *p;
char *tmpbuf, *ptr, **cp;
int num;
size_t len;
res_static rs = __res_get_static();
assert(name != NULL);
_sethtent(rs->stayopen);
ptr = tmpbuf = NULL;
num = 0;
while ((p = _gethtent()) != NULL && num < MAXADDRS) {
if (p->h_addrtype != af)
continue;
if (strcasecmp(p->h_name, name) != 0) {
for (cp = p->h_aliases; *cp != NULL; cp++)
if (strcasecmp(*cp, name) == 0)
break;
if (*cp == NULL) continue;
}
if (num == 0) {
size_t bufsize;
char *src;
bufsize = strlen(p->h_name) + 2 +
MAXADDRS * p->h_length +
ALIGNBYTES;
for (cp = p->h_aliases; *cp != NULL; cp++)
bufsize += strlen(*cp) + 1;
if ((tmpbuf = malloc(bufsize)) == NULL) {
h_errno = NETDB_INTERNAL;
return NULL;
}
ptr = tmpbuf;
src = p->h_name;
while ((*ptr++ = *src++) != '\0');
for (cp = p->h_aliases; *cp != NULL; cp++) {
src = *cp;
while ((*ptr++ = *src++) != '\0');
}
*ptr++ = '\0';
ptr = (char *)(void *)ALIGN(ptr);
}
(void)memcpy(ptr, p->h_addr_list[0], (size_t)p->h_length);
ptr += p->h_length;
num++;
}
_endhtent();
if (num == 0) return NULL;
len = ptr - tmpbuf;
if (len > (sizeof(rs->hostbuf) - ALIGNBYTES)) {
free(tmpbuf);
errno = ENOSPC;
h_errno = NETDB_INTERNAL;
return NULL;
}
ptr = memcpy((void *)ALIGN(rs->hostbuf), tmpbuf, len);
free(tmpbuf);
rs->host.h_name = ptr;
while (*ptr++);
cp = rs->host_aliases;
while (*ptr) {
*cp++ = ptr;
while (*ptr++);
}
ptr++;
*cp = NULL;
ptr = (char *)(void *)ALIGN(ptr);
cp = rs->h_addr_ptrs;
while (num--) {
*cp++ = ptr;
ptr += rs->host.h_length;
}
*cp = NULL;
return &rs->host;
}
/*ARGSUSED*/
static int
_gethtbyaddr(void *rv, void *cb_data, va_list ap)
{
struct hostent *p;
const unsigned char *addr;
int len, af;
res_static rs = __res_get_static();
assert(rv != NULL);
addr = va_arg(ap, unsigned char *);
len = va_arg(ap, int);
af = va_arg(ap, int);
rs->host.h_length = len;
rs->host.h_addrtype = af;
_sethtent(rs->stayopen);
while ((p = _gethtent()) != NULL)
if (p->h_addrtype == af && !memcmp(p->h_addr, addr,
(size_t)len))
break;
_endhtent();
*((struct hostent **)rv) = p;
if (p==NULL) {
h_errno = HOST_NOT_FOUND;
return NS_NOTFOUND;
}
return NS_SUCCESS;
}
static void
map_v4v6_address(const char *src, char *dst)
{
u_char *p = (u_char *)dst;
char tmp[INADDRSZ];
int i;
assert(src != NULL);
assert(dst != NULL);
/* Stash a temporary copy so our caller can update in place. */
(void)memcpy(tmp, src, INADDRSZ);
/* Mark this ipv6 addr as a mapped ipv4. */
for (i = 0; i < 10; i++)
*p++ = 0x00;
*p++ = 0xff;
*p++ = 0xff;
/* Retrieve the saved copy and we're done. */
(void)memcpy((void *)p, tmp, INADDRSZ);
}
static void
map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep)
{
char **ap;
assert(hp != NULL);
assert(bpp != NULL);
assert(ep != NULL);
if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
return;
hp->h_addrtype = AF_INET6;
hp->h_length = IN6ADDRSZ;
for (ap = hp->h_addr_list; *ap; ap++) {
int i = sizeof(align) - (size_t)((u_long)*bpp % sizeof(align));
if (ep - *bpp < (i + IN6ADDRSZ)) {
/* Out of memory. Truncate address list here. XXX */
*ap = NULL;
return;
}
*bpp += i;
map_v4v6_address(*ap, *bpp);
*ap = *bpp;
*bpp += IN6ADDRSZ;
}
}
static void
addrsort(char **ap, int num, res_state res)
{
int i, j;
char **p;
short aval[MAXADDRS];
int needsort = 0;
assert(ap != NULL);
p = ap;
for (i = 0; i < num; i++, p++) {
for (j = 0 ; (unsigned)j < res->nsort; j++)
if (res->sort_list[j].addr.s_addr ==
(((struct in_addr *)(void *)(*p))->s_addr &
res->sort_list[j].mask))
break;
aval[i] = j;
if (needsort == 0 && i > 0 && j < aval[i-1])
needsort = i;
}
if (!needsort)
return;
while (needsort < num) {
for (j = needsort - 1; j >= 0; j--) {
if (aval[j] > aval[j+1]) {
char *hp;
i = aval[j];
aval[j] = aval[j+1];
aval[j+1] = i;
hp = ap[j];
ap[j] = ap[j+1];
ap[j+1] = hp;
} else
break;
}
needsort++;
}
}
struct hostent *
gethostent(void)
{
res_static rs = __res_get_static();
rs->host.h_addrtype = 0;
rs->host.h_length = 0;
return _gethtent();
}
/*ARGSUSED*/
static int
_dns_gethtbyname(void *rv, void *cb_data, va_list ap)
{
querybuf *buf;
int n, type;
struct hostent *hp;
const char *name;
int af;
res_state res;
assert(rv != NULL);
name = va_arg(ap, char *);
/* NOSTRICT skip len */(void)va_arg(ap, int);
af = va_arg(ap, int);
switch (af) {
case AF_INET:
type = T_A;
break;
case AF_INET6:
type = T_AAAA;
break;
default:
return NS_UNAVAIL;
}
buf = malloc(sizeof(*buf));
if (buf == NULL) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
res = __res_get_state();
if (res == NULL) {
free(buf);
return NS_NOTFOUND;
}
n = res_nsearch(res, name, C_IN, type, buf->buf, sizeof(buf->buf));
if (n < 0) {
free(buf);
dprintf("res_nsearch failed (%d)\n", res, n);
__res_put_state(res);
return NS_NOTFOUND;
}
hp = getanswer(buf, n, name, type, res);
free(buf);
__res_put_state(res);
if (hp == NULL)
switch (h_errno) {
case HOST_NOT_FOUND:
return NS_NOTFOUND;
case TRY_AGAIN:
return NS_TRYAGAIN;
default:
return NS_UNAVAIL;
}
*((struct hostent **)rv) = hp;
return NS_SUCCESS;
}
/*ARGSUSED*/
static int
_dns_gethtbyaddr(void *rv, void *cb_data, va_list ap)
{
char qbuf[MAXDNAME + 1], *qp, *ep;
int n;
querybuf *buf;
struct hostent *hp;
const unsigned char *uaddr;
int len, af, advance;
res_state res;
const char* iface;
int mark;
res_static rs = __res_get_static();
assert(rv != NULL);
uaddr = va_arg(ap, unsigned char *);
len = va_arg(ap, int);
af = va_arg(ap, int);
iface = va_arg(ap, char *);
mark = va_arg(ap, int);
switch (af) {
case AF_INET:
(void)snprintf(qbuf, sizeof(qbuf), "%u.%u.%u.%u.in-addr.arpa",
(uaddr[3] & 0xff), (uaddr[2] & 0xff),
(uaddr[1] & 0xff), (uaddr[0] & 0xff));
break;
case AF_INET6:
qp = qbuf;
ep = qbuf + sizeof(qbuf) - 1;
for (n = IN6ADDRSZ - 1; n >= 0; n--) {
advance = snprintf(qp, (size_t)(ep - qp), "%x.%x.",
uaddr[n] & 0xf,
((unsigned int)uaddr[n] >> 4) & 0xf);
if (advance > 0 && qp + advance < ep)
qp += advance;
else {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
}
if (strlcat(qbuf, "ip6.arpa", sizeof(qbuf)) >= sizeof(qbuf)) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
break;
default:
abort();
}
buf = malloc(sizeof(*buf));
if (buf == NULL) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
res = __res_get_state();
if (res == NULL) {
free(buf);
return NS_NOTFOUND;
}
res_setiface(res, iface);
res_setmark(res, mark);
n = res_nquery(res, qbuf, C_IN, T_PTR, buf->buf, sizeof(buf->buf));
if (n < 0) {
free(buf);
dprintf("res_nquery failed (%d)\n", res, n);
__res_put_state(res);
return NS_NOTFOUND;
}
hp = getanswer(buf, n, qbuf, T_PTR, res);
free(buf);
if (hp == NULL) {
__res_put_state(res);
switch (h_errno) {
case HOST_NOT_FOUND:
return NS_NOTFOUND;
case TRY_AGAIN:
return NS_TRYAGAIN;
default:
return NS_UNAVAIL;
}
}
hp->h_addrtype = af;
hp->h_length = len;
(void)memcpy(rs->host_addr, uaddr, (size_t)len);
rs->h_addr_ptrs[0] = (char *)(void *)rs->host_addr;
rs->h_addr_ptrs[1] = NULL;
if (af == AF_INET && (res->options & RES_USE_INET6)) {
map_v4v6_address((char *)(void *)rs->host_addr,
(char *)(void *)rs->host_addr);
hp->h_addrtype = AF_INET6;
hp->h_length = IN6ADDRSZ;
}
__res_put_state(res);
*((struct hostent **)rv) = hp;
h_errno = NETDB_SUCCESS;
return NS_SUCCESS;
}