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bionic/libc/dns/net/getaddrinfo.c
Nick Kralevich 1781ed7774 add CLOEXEC to various DNS related code 
Occasionally file descriptors seem to be leaking across execs
from DNS related calls. Set close-on-execute for the various
sockets / file to prevent file descriptor leakage.

Change-Id: I4724b47bc7236f40c29518a6075598a9bba48b0a
2014-06-29 20:46:17 -07:00

2439 lines
59 KiB
C
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/* $NetBSD: getaddrinfo.c,v 1.82 2006/03/25 12:09:40 rpaulo Exp $ */
/* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 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.
*/
/*
* Issues to be discussed:
* - Thread safe-ness must be checked.
* - Return values. There are nonstandard return values defined and used
* in the source code. This is because RFC2553 is silent about which error
* code must be returned for which situation.
* - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2
* says to use inet_aton() to convert IPv4 numeric to binary (alows
* classful form as a result).
* current code - disallow classful form for IPv4 (due to use of inet_pton).
* - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is
* invalid.
* current code - SEGV on freeaddrinfo(NULL)
* Note:
* - We use getipnodebyname() just for thread-safeness. There's no intent
* to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to
* getipnodebyname().
* - The code filters out AFs that are not supported by the kernel,
* when globbing NULL hostname (to loopback, or wildcard). Is it the right
* thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG
* in ai_flags?
* - (post-2553) semantics of AI_ADDRCONFIG itself is too vague.
* (1) what should we do against numeric hostname (2) what should we do
* against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready?
* non-loopback address configured? global address configured?
* - To avoid search order issue, we have a big amount of code duplicate
* from gethnamaddr.c and some other places. The issues that there's no
* lower layer function to lookup "IPv4 or IPv6" record. Calling
* gethostbyname2 from getaddrinfo will end up in wrong search order, as
* follows:
* - The code makes use of following calls when asked to resolver with
* ai_family = PF_UNSPEC:
* getipnodebyname(host, AF_INET6);
* getipnodebyname(host, AF_INET);
* This will result in the following queries if the node is configure to
* prefer /etc/hosts than DNS:
* lookup /etc/hosts for IPv6 address
* lookup DNS for IPv6 address
* lookup /etc/hosts for IPv4 address
* lookup DNS for IPv4 address
* which may not meet people's requirement.
* The right thing to happen is to have underlying layer which does
* PF_UNSPEC lookup (lookup both) and return chain of addrinfos.
* This would result in a bit of code duplicate with _dns_ghbyname() and
* friends.
*/
#include <fcntl.h>
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include "NetdClientDispatch.h"
#include "resolv_cache.h"
#include "resolv_netid.h"
#include "resolv_private.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <syslog.h>
#include <stdarg.h>
#include "nsswitch.h"
#ifdef ANDROID_CHANGES
#include <sys/system_properties.h>
#endif /* ANDROID_CHANGES */
typedef union sockaddr_union {
struct sockaddr generic;
struct sockaddr_in in;
struct sockaddr_in6 in6;
} sockaddr_union;
#define SUCCESS 0
#define ANY 0
#define YES 1
#define NO 0
static const char in_addrany[] = { 0, 0, 0, 0 };
static const char in_loopback[] = { 127, 0, 0, 1 };
#ifdef INET6
static const char in6_addrany[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const char in6_loopback[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
};
#endif
// This should be synchronized to ResponseCode.h
static const int DnsProxyQueryResult = 222;
static const struct afd {
int a_af;
int a_addrlen;
int a_socklen;
int a_off;
const char *a_addrany;
const char *a_loopback;
int a_scoped;
} afdl [] = {
#ifdef INET6
{PF_INET6, sizeof(struct in6_addr),
sizeof(struct sockaddr_in6),
offsetof(struct sockaddr_in6, sin6_addr),
in6_addrany, in6_loopback, 1},
#endif
{PF_INET, sizeof(struct in_addr),
sizeof(struct sockaddr_in),
offsetof(struct sockaddr_in, sin_addr),
in_addrany, in_loopback, 0},
{0, 0, 0, 0, NULL, NULL, 0},
};
struct explore {
int e_af;
int e_socktype;
int e_protocol;
const char *e_protostr;
int e_wild;
#define WILD_AF(ex) ((ex)->e_wild & 0x01)
#define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02)
#define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04)
};
static const struct explore explore[] = {
#if 0
{ PF_LOCAL, 0, ANY, ANY, NULL, 0x01 },
#endif
#ifdef INET6
{ PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_INET6, SOCK_RAW, ANY, NULL, 0x05 },
#endif
{ PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_INET, SOCK_RAW, ANY, NULL, 0x05 },
{ PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 },
{ PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 },
{ PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 },
{ -1, 0, 0, NULL, 0 },
};
#ifdef INET6
#define PTON_MAX 16
#else
#define PTON_MAX 4
#endif
static const ns_src default_dns_files[] = {
{ NSSRC_FILES, NS_SUCCESS },
{ NSSRC_DNS, NS_SUCCESS },
{ 0, 0 }
};
#define MAXPACKET (64*1024)
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
struct res_target {
struct res_target *next;
const char *name; /* domain name */
int qclass, qtype; /* class and type of query */
u_char *answer; /* buffer to put answer */
int anslen; /* size of answer buffer */
int n; /* result length */
};
static int str2number(const char *);
static int explore_fqdn(const struct addrinfo *, const char *,
const char *, struct addrinfo **, unsigned netid, unsigned mark);
static int explore_null(const struct addrinfo *,
const char *, struct addrinfo **);
static int explore_numeric(const struct addrinfo *, const char *,
const char *, struct addrinfo **, const char *);
static int explore_numeric_scope(const struct addrinfo *, const char *,
const char *, struct addrinfo **);
static int get_canonname(const struct addrinfo *,
struct addrinfo *, const char *);
static struct addrinfo *get_ai(const struct addrinfo *,
const struct afd *, const char *);
static int get_portmatch(const struct addrinfo *, const char *);
static int get_port(const struct addrinfo *, const char *, int);
static const struct afd *find_afd(int);
#ifdef INET6
static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *);
#endif
static struct addrinfo *getanswer(const querybuf *, int, const char *, int,
const struct addrinfo *);
static int _dns_getaddrinfo(void *, void *, va_list);
static void _sethtent(FILE **);
static void _endhtent(FILE **);
static struct addrinfo *_gethtent(FILE **, const char *,
const struct addrinfo *);
static int _files_getaddrinfo(void *, void *, va_list);
static int res_queryN(const char *, struct res_target *, res_state);
static int res_searchN(const char *, struct res_target *, res_state);
static int res_querydomainN(const char *, const char *,
struct res_target *, res_state);
static const char * const ai_errlist[] = {
"Success",
"Address family for hostname not supported", /* EAI_ADDRFAMILY */
"Temporary failure in name resolution", /* EAI_AGAIN */
"Invalid value for ai_flags", /* EAI_BADFLAGS */
"Non-recoverable failure in name resolution", /* EAI_FAIL */
"ai_family not supported", /* EAI_FAMILY */
"Memory allocation failure", /* EAI_MEMORY */
"No address associated with hostname", /* EAI_NODATA */
"hostname nor servname provided, or not known", /* EAI_NONAME */
"servname not supported for ai_socktype", /* EAI_SERVICE */
"ai_socktype not supported", /* EAI_SOCKTYPE */
"System error returned in errno", /* EAI_SYSTEM */
"Invalid value for hints", /* EAI_BADHINTS */
"Resolved protocol is unknown", /* EAI_PROTOCOL */
"Argument buffer overflow", /* EAI_OVERFLOW */
"Unknown error", /* EAI_MAX */
};
/* XXX macros that make external reference is BAD. */
#define GET_AI(ai, afd, addr) \
do { \
/* external reference: pai, error, and label free */ \
(ai) = get_ai(pai, (afd), (addr)); \
if ((ai) == NULL) { \
error = EAI_MEMORY; \
goto free; \
} \
} while (/*CONSTCOND*/0)
#define GET_PORT(ai, serv) \
do { \
/* external reference: error and label free */ \
error = get_port((ai), (serv), 0); \
if (error != 0) \
goto free; \
} while (/*CONSTCOND*/0)
#define GET_CANONNAME(ai, str) \
do { \
/* external reference: pai, error and label free */ \
error = get_canonname(pai, (ai), (str)); \
if (error != 0) \
goto free; \
} while (/*CONSTCOND*/0)
#define ERR(err) \
do { \
/* external reference: error, and label bad */ \
error = (err); \
goto bad; \
/*NOTREACHED*/ \
} while (/*CONSTCOND*/0)
#define MATCH_FAMILY(x, y, w) \
((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \
(y) == PF_UNSPEC)))
#define MATCH(x, y, w) \
((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY)))
const char *
gai_strerror(int ecode)
{
if (ecode < 0 || ecode > EAI_MAX)
ecode = EAI_MAX;
return ai_errlist[ecode];
}
void
freeaddrinfo(struct addrinfo *ai)
{
struct addrinfo *next;
assert(ai != NULL);
do {
next = ai->ai_next;
if (ai->ai_canonname)
free(ai->ai_canonname);
/* no need to free(ai->ai_addr) */
free(ai);
ai = next;
} while (ai);
}
static int
str2number(const char *p)
{
char *ep;
unsigned long v;
assert(p != NULL);
if (*p == '\0')
return -1;
ep = NULL;
errno = 0;
v = strtoul(p, &ep, 10);
if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
return v;
else
return -1;
}
/*
* Connect a UDP socket to a given unicast address. This will cause no network
* traffic, but will fail fast if the system has no or limited reachability to
* the destination (e.g., no IPv4 address, no IPv6 default route, ...).
*/
static int
_test_connect(int pf, struct sockaddr *addr, size_t addrlen, unsigned mark) {
int s = socket(pf, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
if (s < 0)
return 0;
if (mark != MARK_UNSET && setsockopt(s, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
return 0;
int ret;
do {
ret = connect(s, addr, addrlen);
} while (ret < 0 && errno == EINTR);
int success = (ret == 0);
do {
ret = close(s);
} while (ret < 0 && errno == EINTR);
return success;
}
/*
* The following functions determine whether IPv4 or IPv6 connectivity is
* available in order to implement AI_ADDRCONFIG.
*
* Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
* available, but whether addresses of the specified family are "configured
* on the local system". However, bionic doesn't currently support getifaddrs,
* so checking for connectivity is the next best thing.
*/
static int
_have_ipv6(unsigned mark) {
static const struct sockaddr_in6 sin6_test = {
.sin6_family = AF_INET6,
.sin6_addr.s6_addr = { // 2000::
0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
};
sockaddr_union addr = { .in6 = sin6_test };
return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6), mark);
}
static int
_have_ipv4(unsigned mark) {
static const struct sockaddr_in sin_test = {
.sin_family = AF_INET,
.sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
};
sockaddr_union addr = { .in = sin_test };
return _test_connect(PF_INET, &addr.generic, sizeof(addr.in), mark);
}
// Returns 0 on success, else returns on error.
static int
android_getaddrinfo_proxy(
const char *hostname, const char *servname,
const struct addrinfo *hints, struct addrinfo **res, unsigned netid)
{
int sock;
const int one = 1;
struct sockaddr_un proxy_addr;
FILE* proxy = NULL;
int success = 0;
// Clear this at start, as we use its non-NULLness later (in the
// error path) to decide if we have to free up any memory we
// allocated in the process (before failing).
*res = NULL;
// Bogus things we can't serialize. Don't use the proxy. These will fail - let them.
if ((hostname != NULL &&
strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) ||
(servname != NULL &&
strcspn(servname, " \n\r\t^'\"") != strlen(servname))) {
return EAI_NODATA;
}
sock = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (sock < 0) {
return EAI_NODATA;
}
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 EAI_NODATA;
}
netid = __netdClientDispatch.netIdForResolv(netid);
// Send the request.
proxy = fdopen(sock, "r+");
if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d %u",
hostname == NULL ? "^" : hostname,
servname == NULL ? "^" : servname,
hints == NULL ? -1 : hints->ai_flags,
hints == NULL ? -1 : hints->ai_family,
hints == NULL ? -1 : hints->ai_socktype,
hints == NULL ? -1 : hints->ai_protocol,
netid) < 0) {
goto exit;
}
// literal NULL byte at end, required by FrameworkListener
if (fputc(0, proxy) == EOF ||
fflush(proxy) != 0) {
goto exit;
}
char buf[4];
// read result code for gethostbyaddr
if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) {
goto exit;
}
int result_code = (int)strtol(buf, NULL, 10);
// verify the code itself
if (result_code != DnsProxyQueryResult ) {
fread(buf, 1, sizeof(buf), proxy);
goto exit;
}
struct addrinfo* ai = NULL;
struct addrinfo** nextres = res;
while (1) {
uint32_t addrinfo_len;
if (fread(&addrinfo_len, sizeof(addrinfo_len),
1, proxy) != 1) {
break;
}
addrinfo_len = ntohl(addrinfo_len);
if (addrinfo_len == 0) {
success = 1;
break;
}
if (addrinfo_len < sizeof(struct addrinfo)) {
break;
}
struct addrinfo* ai = calloc(1, addrinfo_len +
sizeof(struct sockaddr_storage));
if (ai == NULL) {
break;
}
if (fread(ai, addrinfo_len, 1, proxy) != 1) {
// Error; fall through.
break;
}
// Zero out the pointer fields we copied which aren't
// valid in this address space.
ai->ai_addr = NULL;
ai->ai_canonname = NULL;
ai->ai_next = NULL;
// struct sockaddr
uint32_t addr_len;
if (fread(&addr_len, sizeof(addr_len), 1, proxy) != 1) {
break;
}
addr_len = ntohl(addr_len);
if (addr_len != 0) {
if (addr_len > sizeof(struct sockaddr_storage)) {
// Bogus; too big.
break;
}
struct sockaddr* addr = (struct sockaddr*)(ai + 1);
if (fread(addr, addr_len, 1, proxy) != 1) {
break;
}
ai->ai_addr = addr;
}
// cannonname
uint32_t name_len;
if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) {
break;
}
name_len = ntohl(name_len);
if (name_len != 0) {
ai->ai_canonname = (char*) malloc(name_len);
if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) {
break;
}
if (ai->ai_canonname[name_len - 1] != '\0') {
// The proxy should be returning this
// NULL-terminated.
break;
}
}
*nextres = ai;
nextres = &ai->ai_next;
ai = NULL;
}
if (ai != NULL) {
// Clean up partially-built addrinfo that we never ended up
// attaching to the response.
freeaddrinfo(ai);
}
exit:
if (proxy != NULL) {
fclose(proxy);
}
if (success) {
return 0;
}
// Proxy failed;
// clean up memory we might've allocated.
if (*res) {
freeaddrinfo(*res);
*res = NULL;
}
return EAI_NODATA;
}
int
getaddrinfo(const char *hostname, const char *servname,
const struct addrinfo *hints, struct addrinfo **res)
{
return android_getaddrinfofornet(hostname, servname, hints, NETID_UNSET, MARK_UNSET, res);
}
int
android_getaddrinfofornet(const char *hostname, const char *servname,
const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
{
struct addrinfo sentinel;
struct addrinfo *cur;
int error = 0;
struct addrinfo ai;
struct addrinfo ai0;
struct addrinfo *pai;
const struct explore *ex;
const char* cache_mode = getenv("ANDROID_DNS_MODE");
/* hostname is allowed to be NULL */
/* servname is allowed to be NULL */
/* hints is allowed to be NULL */
assert(res != NULL);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
pai = &ai;
pai->ai_flags = 0;
pai->ai_family = PF_UNSPEC;
pai->ai_socktype = ANY;
pai->ai_protocol = ANY;
pai->ai_addrlen = 0;
pai->ai_canonname = NULL;
pai->ai_addr = NULL;
pai->ai_next = NULL;
if (hostname == NULL && servname == NULL)
return EAI_NONAME;
if (hints) {
/* error check for hints */
if (hints->ai_addrlen || hints->ai_canonname ||
hints->ai_addr || hints->ai_next)
ERR(EAI_BADHINTS); /* xxx */
if (hints->ai_flags & ~AI_MASK)
ERR(EAI_BADFLAGS);
switch (hints->ai_family) {
case PF_UNSPEC:
case PF_INET:
#ifdef INET6
case PF_INET6:
#endif
break;
default:
ERR(EAI_FAMILY);
}
memcpy(pai, hints, sizeof(*pai));
/*
* if both socktype/protocol are specified, check if they
* are meaningful combination.
*/
if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) {
for (ex = explore; ex->e_af >= 0; ex++) {
if (pai->ai_family != ex->e_af)
continue;
if (ex->e_socktype == ANY)
continue;
if (ex->e_protocol == ANY)
continue;
if (pai->ai_socktype == ex->e_socktype
&& pai->ai_protocol != ex->e_protocol) {
ERR(EAI_BADHINTS);
}
}
}
}
/*
* check for special cases. (1) numeric servname is disallowed if
* socktype/protocol are left unspecified. (2) servname is disallowed
* for raw and other inet{,6} sockets.
*/
if (MATCH_FAMILY(pai->ai_family, PF_INET, 1)
#ifdef PF_INET6
|| MATCH_FAMILY(pai->ai_family, PF_INET6, 1)
#endif
) {
ai0 = *pai; /* backup *pai */
if (pai->ai_family == PF_UNSPEC) {
#ifdef PF_INET6
pai->ai_family = PF_INET6;
#else
pai->ai_family = PF_INET;
#endif
}
error = get_portmatch(pai, servname);
if (error)
ERR(error);
*pai = ai0;
}
ai0 = *pai;
/* NULL hostname, or numeric hostname */
for (ex = explore; ex->e_af >= 0; ex++) {
*pai = ai0;
/* PF_UNSPEC entries are prepared for DNS queries only */
if (ex->e_af == PF_UNSPEC)
continue;
if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex)))
continue;
if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex)))
continue;
if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex)))
continue;
if (pai->ai_family == PF_UNSPEC)
pai->ai_family = ex->e_af;
if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
pai->ai_socktype = ex->e_socktype;
if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
pai->ai_protocol = ex->e_protocol;
if (hostname == NULL)
error = explore_null(pai, servname, &cur->ai_next);
else
error = explore_numeric_scope(pai, hostname, servname,
&cur->ai_next);
if (error)
goto free;
while (cur->ai_next)
cur = cur->ai_next;
}
/*
* XXX
* If numeric representation of AF1 can be interpreted as FQDN
* representation of AF2, we need to think again about the code below.
*/
if (sentinel.ai_next)
goto good;
if (hostname == NULL)
ERR(EAI_NODATA);
if (pai->ai_flags & AI_NUMERICHOST)
ERR(EAI_NONAME);
/*
* BEGIN ANDROID CHANGES; proxying to the cache
*/
if (cache_mode == NULL || strcmp(cache_mode, "local") != 0) {
// we're not the proxy - pass the request to them
return android_getaddrinfo_proxy(hostname, servname, hints, res, netid);
}
/*
* hostname as alphabetical name.
* we would like to prefer AF_INET6 than AF_INET, so we'll make a
* outer loop by AFs.
*/
for (ex = explore; ex->e_af >= 0; ex++) {
*pai = ai0;
/* require exact match for family field */
if (pai->ai_family != ex->e_af)
continue;
if (!MATCH(pai->ai_socktype, ex->e_socktype,
WILD_SOCKTYPE(ex))) {
continue;
}
if (!MATCH(pai->ai_protocol, ex->e_protocol,
WILD_PROTOCOL(ex))) {
continue;
}
if (pai->ai_socktype == ANY && ex->e_socktype != ANY)
pai->ai_socktype = ex->e_socktype;
if (pai->ai_protocol == ANY && ex->e_protocol != ANY)
pai->ai_protocol = ex->e_protocol;
error = explore_fqdn(pai, hostname, servname,
&cur->ai_next, netid, mark);
while (cur && cur->ai_next)
cur = cur->ai_next;
}
/* XXX */
if (sentinel.ai_next)
error = 0;
if (error)
goto free;
if (error == 0) {
if (sentinel.ai_next) {
good:
*res = sentinel.ai_next;
return SUCCESS;
} else
error = EAI_FAIL;
}
free:
bad:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
*res = NULL;
return error;
}
/*
* FQDN hostname, DNS lookup
*/
static int
explore_fqdn(const struct addrinfo *pai, const char *hostname,
const char *servname, struct addrinfo **res, unsigned netid, unsigned mark)
{
struct addrinfo *result;
struct addrinfo *cur;
int error = 0;
static const ns_dtab dtab[] = {
NS_FILES_CB(_files_getaddrinfo, NULL)
{ NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */
NS_NIS_CB(_yp_getaddrinfo, NULL)
{ 0, 0, 0 }
};
assert(pai != NULL);
/* hostname may be NULL */
/* servname may be NULL */
assert(res != NULL);
result = NULL;
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo",
default_dns_files, hostname, pai, netid, mark)) {
case NS_TRYAGAIN:
error = EAI_AGAIN;
goto free;
case NS_UNAVAIL:
error = EAI_FAIL;
goto free;
case NS_NOTFOUND:
error = EAI_NODATA;
goto free;
case NS_SUCCESS:
error = 0;
for (cur = result; cur; cur = cur->ai_next) {
GET_PORT(cur, servname);
/* canonname should be filled already */
}
break;
}
*res = result;
return 0;
free:
if (result)
freeaddrinfo(result);
return error;
}
/*
* hostname == NULL.
* passive socket -> anyaddr (0.0.0.0 or ::)
* non-passive socket -> localhost (127.0.0.1 or ::1)
*/
static int
explore_null(const struct addrinfo *pai, const char *servname,
struct addrinfo **res)
{
int s;
const struct afd *afd;
struct addrinfo *cur;
struct addrinfo sentinel;
int error;
assert(pai != NULL);
/* servname may be NULL */
assert(res != NULL);
*res = NULL;
sentinel.ai_next = NULL;
cur = &sentinel;
/*
* filter out AFs that are not supported by the kernel
* XXX errno?
*/
s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (s < 0) {
if (errno != EMFILE)
return 0;
} else
close(s);
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
if (pai->ai_flags & AI_PASSIVE) {
GET_AI(cur->ai_next, afd, afd->a_addrany);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "anyaddr");
*/
GET_PORT(cur->ai_next, servname);
} else {
GET_AI(cur->ai_next, afd, afd->a_loopback);
/* xxx meaningless?
* GET_CANONNAME(cur->ai_next, "localhost");
*/
GET_PORT(cur->ai_next, servname);
}
cur = cur->ai_next;
*res = sentinel.ai_next;
return 0;
free:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
return error;
}
/*
* numeric hostname
*/
static int
explore_numeric(const struct addrinfo *pai, const char *hostname,
const char *servname, struct addrinfo **res, const char *canonname)
{
const struct afd *afd;
struct addrinfo *cur;
struct addrinfo sentinel;
int error;
char pton[PTON_MAX];
assert(pai != NULL);
/* hostname may be NULL */
/* servname may be NULL */
assert(res != NULL);
*res = NULL;
sentinel.ai_next = NULL;
cur = &sentinel;
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
switch (afd->a_af) {
#if 0 /*X/Open spec*/
case AF_INET:
if (inet_aton(hostname, (struct in_addr *)pton) == 1) {
if (pai->ai_family == afd->a_af ||
pai->ai_family == PF_UNSPEC /*?*/) {
GET_AI(cur->ai_next, afd, pton);
GET_PORT(cur->ai_next, servname);
if ((pai->ai_flags & AI_CANONNAME)) {
/*
* Set the numeric address itself as
* the canonical name, based on a
* clarification in rfc2553bis-03.
*/
GET_CANONNAME(cur->ai_next, canonname);
}
while (cur && cur->ai_next)
cur = cur->ai_next;
} else
ERR(EAI_FAMILY); /*xxx*/
}
break;
#endif
default:
if (inet_pton(afd->a_af, hostname, pton) == 1) {
if (pai->ai_family == afd->a_af ||
pai->ai_family == PF_UNSPEC /*?*/) {
GET_AI(cur->ai_next, afd, pton);
GET_PORT(cur->ai_next, servname);
if ((pai->ai_flags & AI_CANONNAME)) {
/*
* Set the numeric address itself as
* the canonical name, based on a
* clarification in rfc2553bis-03.
*/
GET_CANONNAME(cur->ai_next, canonname);
}
while (cur->ai_next)
cur = cur->ai_next;
} else
ERR(EAI_FAMILY); /*xxx*/
}
break;
}
*res = sentinel.ai_next;
return 0;
free:
bad:
if (sentinel.ai_next)
freeaddrinfo(sentinel.ai_next);
return error;
}
/*
* numeric hostname with scope
*/
static int
explore_numeric_scope(const struct addrinfo *pai, const char *hostname,
const char *servname, struct addrinfo **res)
{
#if !defined(SCOPE_DELIMITER) || !defined(INET6)
return explore_numeric(pai, hostname, servname, res, hostname);
#else
const struct afd *afd;
struct addrinfo *cur;
int error;
char *cp, *hostname2 = NULL, *scope, *addr;
struct sockaddr_in6 *sin6;
assert(pai != NULL);
/* hostname may be NULL */
/* servname may be NULL */
assert(res != NULL);
/*
* if the servname does not match socktype/protocol, ignore it.
*/
if (get_portmatch(pai, servname) != 0)
return 0;
afd = find_afd(pai->ai_family);
if (afd == NULL)
return 0;
if (!afd->a_scoped)
return explore_numeric(pai, hostname, servname, res, hostname);
cp = strchr(hostname, SCOPE_DELIMITER);
if (cp == NULL)
return explore_numeric(pai, hostname, servname, res, hostname);
/*
* Handle special case of <scoped_address><delimiter><scope id>
*/
hostname2 = strdup(hostname);
if (hostname2 == NULL)
return EAI_MEMORY;
/* terminate at the delimiter */
hostname2[cp - hostname] = '\0';
addr = hostname2;
scope = cp + 1;
error = explore_numeric(pai, addr, servname, res, hostname);
if (error == 0) {
u_int32_t scopeid;
for (cur = *res; cur; cur = cur->ai_next) {
if (cur->ai_family != AF_INET6)
continue;
sin6 = (struct sockaddr_in6 *)(void *)cur->ai_addr;
if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
free(hostname2);
return(EAI_NODATA); /* XXX: is return OK? */
}
sin6->sin6_scope_id = scopeid;
}
}
free(hostname2);
return error;
#endif
}
static int
get_canonname(const struct addrinfo *pai, struct addrinfo *ai, const char *str)
{
assert(pai != NULL);
assert(ai != NULL);
assert(str != NULL);
if ((pai->ai_flags & AI_CANONNAME) != 0) {
ai->ai_canonname = strdup(str);
if (ai->ai_canonname == NULL)
return EAI_MEMORY;
}
return 0;
}
static struct addrinfo *
get_ai(const struct addrinfo *pai, const struct afd *afd, const char *addr)
{
char *p;
struct addrinfo *ai;
assert(pai != NULL);
assert(afd != NULL);
assert(addr != NULL);
ai = (struct addrinfo *)malloc(sizeof(struct addrinfo)
+ (afd->a_socklen));
if (ai == NULL)
return NULL;
memcpy(ai, pai, sizeof(struct addrinfo));
ai->ai_addr = (struct sockaddr *)(void *)(ai + 1);
memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
#ifdef HAVE_SA_LEN
ai->ai_addr->sa_len = afd->a_socklen;
#endif
ai->ai_addrlen = afd->a_socklen;
#if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__)
ai->__ai_pad0 = 0;
#endif
ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
p = (char *)(void *)(ai->ai_addr);
memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
return ai;
}
static int
get_portmatch(const struct addrinfo *ai, const char *servname)
{
assert(ai != NULL);
/* servname may be NULL */
return get_port(ai, servname, 1);
}
static int
get_port(const struct addrinfo *ai, const char *servname, int matchonly)
{
const char *proto;
struct servent *sp;
int port;
int allownumeric;
assert(ai != NULL);
/* servname may be NULL */
if (servname == NULL)
return 0;
switch (ai->ai_family) {
case AF_INET:
#ifdef AF_INET6
case AF_INET6:
#endif
break;
default:
return 0;
}
switch (ai->ai_socktype) {
case SOCK_RAW:
return EAI_SERVICE;
case SOCK_DGRAM:
case SOCK_STREAM:
allownumeric = 1;
break;
case ANY:
#if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */
allownumeric = 1;
#else
allownumeric = 0;
#endif
break;
default:
return EAI_SOCKTYPE;
}
port = str2number(servname);
if (port >= 0) {
if (!allownumeric)
return EAI_SERVICE;
if (port < 0 || port > 65535)
return EAI_SERVICE;
port = htons(port);
} else {
if (ai->ai_flags & AI_NUMERICSERV)
return EAI_NONAME;
switch (ai->ai_socktype) {
case SOCK_DGRAM:
proto = "udp";
break;
case SOCK_STREAM:
proto = "tcp";
break;
default:
proto = NULL;
break;
}
if ((sp = getservbyname(servname, proto)) == NULL)
return EAI_SERVICE;
port = sp->s_port;
}
if (!matchonly) {
switch (ai->ai_family) {
case AF_INET:
((struct sockaddr_in *)(void *)
ai->ai_addr)->sin_port = port;
break;
#ifdef INET6
case AF_INET6:
((struct sockaddr_in6 *)(void *)
ai->ai_addr)->sin6_port = port;
break;
#endif
}
}
return 0;
}
static const struct afd *
find_afd(int af)
{
const struct afd *afd;
if (af == PF_UNSPEC)
return NULL;
for (afd = afdl; afd->a_af; afd++) {
if (afd->a_af == af)
return afd;
}
return NULL;
}
#ifdef INET6
/* convert a string to a scope identifier. XXX: IPv6 specific */
static int
ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid)
{
u_long lscopeid;
struct in6_addr *a6;
char *ep;
assert(scope != NULL);
assert(sin6 != NULL);
assert(scopeid != NULL);
a6 = &sin6->sin6_addr;
/* empty scopeid portion is invalid */
if (*scope == '\0')
return -1;
if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
/*
* We currently assume a one-to-one mapping between links
* and interfaces, so we simply use interface indices for
* like-local scopes.
*/
*scopeid = if_nametoindex(scope);
if (*scopeid == 0)
goto trynumeric;
return 0;
}
/* still unclear about literal, allow numeric only - placeholder */
if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6))
goto trynumeric;
if (IN6_IS_ADDR_MC_ORGLOCAL(a6))
goto trynumeric;
else
goto trynumeric; /* global */
/* try to convert to a numeric id as a last resort */
trynumeric:
errno = 0;
lscopeid = strtoul(scope, &ep, 10);
*scopeid = (u_int32_t)(lscopeid & 0xffffffffUL);
if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
return 0;
else
return -1;
}
#endif
/* code duplicate with gethnamaddr.c */
static const char AskedForGot[] =
"gethostby*.getanswer: asked for \"%s\", got \"%s\"";
static struct addrinfo *
getanswer(const querybuf *answer, int anslen, const char *qname, int qtype,
const struct addrinfo *pai)
{
struct addrinfo sentinel, *cur;
struct addrinfo ai;
const struct afd *afd;
char *canonname;
const HEADER *hp;
const u_char *cp;
int n;
const u_char *eom;
char *bp, *ep;
int type, class, ancount, qdcount;
int haveanswer, had_error;
char tbuf[MAXDNAME];
int (*name_ok) (const char *);
char hostbuf[8*1024];
assert(answer != NULL);
assert(qname != NULL);
assert(pai != NULL);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
canonname = NULL;
eom = answer->buf + anslen;
switch (qtype) {
case T_A:
case T_AAAA:
case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
name_ok = res_hnok;
break;
default:
return NULL; /* XXX should be abort(); */
}
/*
* find first satisfactory answer
*/
hp = &answer->hdr;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
bp = hostbuf;
ep = hostbuf + sizeof hostbuf;
cp = answer->buf + 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);
}
cp += n + QFIXEDSZ;
if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
/* 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);
}
canonname = bp;
bp += n;
/* The qname can be abbreviated, but h_name is now absolute. */
qname = canonname;
}
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 */
type = _getshort(cp);
cp += INT16SZ; /* type */
class = _getshort(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = _getshort(cp);
cp += INT16SZ; /* len */
if (class != C_IN) {
/* XXX - debug? syslog? */
cp += n;
continue; /* XXX - had_error++ ? */
}
if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
type == T_CNAME) {
n = dn_expand(answer->buf, eom, cp, tbuf, sizeof tbuf);
if ((n < 0) || !(*name_ok)(tbuf)) {
had_error++;
continue;
}
cp += 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));
canonname = bp;
bp += n;
continue;
}
if (qtype == T_ANY) {
if (!(type == T_A || type == T_AAAA)) {
cp += n;
continue;
}
} else 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_A:
case T_AAAA:
if (strcasecmp(canonname, bp) != 0) {
syslog(LOG_NOTICE|LOG_AUTH,
AskedForGot, canonname, bp);
cp += n;
continue; /* XXX - had_error++ ? */
}
if (type == T_A && n != INADDRSZ) {
cp += n;
continue;
}
if (type == T_AAAA && n != IN6ADDRSZ) {
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;
canonname = bp;
nn = strlen(bp) + 1; /* for the \0 */
bp += nn;
}
/* don't overwrite pai */
ai = *pai;
ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
afd = find_afd(ai.ai_family);
if (afd == NULL) {
cp += n;
continue;
}
cur->ai_next = get_ai(&ai, afd, (const char *)cp);
if (cur->ai_next == NULL)
had_error++;
while (cur && cur->ai_next)
cur = cur->ai_next;
cp += n;
break;
default:
abort();
}
if (!had_error)
haveanswer++;
}
if (haveanswer) {
if (!canonname)
(void)get_canonname(pai, sentinel.ai_next, qname);
else
(void)get_canonname(pai, sentinel.ai_next, canonname);
h_errno = NETDB_SUCCESS;
return sentinel.ai_next;
}
h_errno = NO_RECOVERY;
return NULL;
}
struct addrinfo_sort_elem {
struct addrinfo *ai;
int has_src_addr;
sockaddr_union src_addr;
int original_order;
};
/*ARGSUSED*/
static int
_get_scope(const struct sockaddr *addr)
{
if (addr->sa_family == AF_INET6) {
const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
} else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
/*
* RFC 4291 section 2.5.3 says loopback is to be treated as having
* link-local scope.
*/
return IPV6_ADDR_SCOPE_LINKLOCAL;
} else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
return IPV6_ADDR_SCOPE_SITELOCAL;
} else {
return IPV6_ADDR_SCOPE_GLOBAL;
}
} else if (addr->sa_family == AF_INET) {
const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr;
unsigned long int na = ntohl(addr4->sin_addr.s_addr);
if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
(na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
return IPV6_ADDR_SCOPE_LINKLOCAL;
} else {
/*
* RFC 6724 section 3.2. Other IPv4 addresses, including private addresses
* and shared addresses (100.64.0.0/10), are assigned global scope.
*/
return IPV6_ADDR_SCOPE_GLOBAL;
}
} else {
/*
* This should never happen.
* Return a scope with low priority as a last resort.
*/
return IPV6_ADDR_SCOPE_NODELOCAL;
}
}
/* These macros are modelled after the ones in <netinet/in6.h>. */
/* RFC 4380, section 2.6 */
#define IN6_IS_ADDR_TEREDO(a) \
((*(const uint32_t *)(const void *)(&(a)->s6_addr[0]) == ntohl(0x20010000)))
/* RFC 3056, section 2. */
#define IN6_IS_ADDR_6TO4(a) \
(((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
/* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
#define IN6_IS_ADDR_6BONE(a) \
(((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
/*
* Get the label for a given IPv4/IPv6 address.
* RFC 6724, section 2.1.
*/
/*ARGSUSED*/
static int
_get_label(const struct sockaddr *addr)
{
if (addr->sa_family == AF_INET) {
return 4;
} else if (addr->sa_family == AF_INET6) {
const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
return 0;
} else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
return 4;
} else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
return 2;
} else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
return 5;
} else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
return 13;
} else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
return 3;
} else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
return 11;
} else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
return 12;
} else {
/* All other IPv6 addresses, including global unicast addresses. */
return 1;
}
} else {
/*
* This should never happen.
* Return a semi-random label as a last resort.
*/
return 1;
}
}
/*
* Get the precedence for a given IPv4/IPv6 address.
* RFC 6724, section 2.1.
*/
/*ARGSUSED*/
static int
_get_precedence(const struct sockaddr *addr)
{
if (addr->sa_family == AF_INET) {
return 35;
} else if (addr->sa_family == AF_INET6) {
const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
return 50;
} else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
return 35;
} else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
return 30;
} else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
return 5;
} else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
return 3;
} else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
return 1;
} else {
/* All other IPv6 addresses, including global unicast addresses. */
return 40;
}
} else {
return 1;
}
}
/*
* Find number of matching initial bits between the two addresses a1 and a2.
*/
/*ARGSUSED*/
static int
_common_prefix_len(const struct in6_addr *a1, const struct in6_addr *a2)
{
const char *p1 = (const char *)a1;
const char *p2 = (const char *)a2;
unsigned i;
for (i = 0; i < sizeof(*a1); ++i) {
int x, j;
if (p1[i] == p2[i]) {
continue;
}
x = p1[i] ^ p2[i];
for (j = 0; j < CHAR_BIT; ++j) {
if (x & (1 << (CHAR_BIT - 1))) {
return i * CHAR_BIT + j;
}
x <<= 1;
}
}
return sizeof(*a1) * CHAR_BIT;
}
/*
* Compare two source/destination address pairs.
* RFC 6724, section 6.
*/
/*ARGSUSED*/
static int
_rfc6724_compare(const void *ptr1, const void* ptr2)
{
const struct addrinfo_sort_elem *a1 = (const struct addrinfo_sort_elem *)ptr1;
const struct addrinfo_sort_elem *a2 = (const struct addrinfo_sort_elem *)ptr2;
int scope_src1, scope_dst1, scope_match1;
int scope_src2, scope_dst2, scope_match2;
int label_src1, label_dst1, label_match1;
int label_src2, label_dst2, label_match2;
int precedence1, precedence2;
int prefixlen1, prefixlen2;
/* Rule 1: Avoid unusable destinations. */
if (a1->has_src_addr != a2->has_src_addr) {
return a2->has_src_addr - a1->has_src_addr;
}
/* Rule 2: Prefer matching scope. */
scope_src1 = _get_scope(&a1->src_addr.generic);
scope_dst1 = _get_scope(a1->ai->ai_addr);
scope_match1 = (scope_src1 == scope_dst1);
scope_src2 = _get_scope(&a2->src_addr.generic);
scope_dst2 = _get_scope(a2->ai->ai_addr);
scope_match2 = (scope_src2 == scope_dst2);
if (scope_match1 != scope_match2) {
return scope_match2 - scope_match1;
}
/*
* Rule 3: Avoid deprecated addresses.
* TODO(sesse): We don't currently have a good way of finding this.
*/
/*
* Rule 4: Prefer home addresses.
* TODO(sesse): We don't currently have a good way of finding this.
*/
/* Rule 5: Prefer matching label. */
label_src1 = _get_label(&a1->src_addr.generic);
label_dst1 = _get_label(a1->ai->ai_addr);
label_match1 = (label_src1 == label_dst1);
label_src2 = _get_label(&a2->src_addr.generic);
label_dst2 = _get_label(a2->ai->ai_addr);
label_match2 = (label_src2 == label_dst2);
if (label_match1 != label_match2) {
return label_match2 - label_match1;
}
/* Rule 6: Prefer higher precedence. */
precedence1 = _get_precedence(a1->ai->ai_addr);
precedence2 = _get_precedence(a2->ai->ai_addr);
if (precedence1 != precedence2) {
return precedence2 - precedence1;
}
/*
* Rule 7: Prefer native transport.
* TODO(sesse): We don't currently have a good way of finding this.
*/
/* Rule 8: Prefer smaller scope. */
if (scope_dst1 != scope_dst2) {
return scope_dst1 - scope_dst2;
}
/*
* Rule 9: Use longest matching prefix.
* We implement this for IPv6 only, as the rules in RFC 6724 don't seem
* to work very well directly applied to IPv4. (glibc uses information from
* the routing table for a custom IPv4 implementation here.)
*/
if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 &&
a2->has_src_addr && a2->ai->ai_addr->sa_family == AF_INET6) {
const struct sockaddr_in6 *a1_src = &a1->src_addr.in6;
const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr;
const struct sockaddr_in6 *a2_src = &a2->src_addr.in6;
const struct sockaddr_in6 *a2_dst = (const struct sockaddr_in6 *)a2->ai->ai_addr;
prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
if (prefixlen1 != prefixlen2) {
return prefixlen2 - prefixlen1;
}
}
/*
* Rule 10: Leave the order unchanged.
* We need this since qsort() is not necessarily stable.
*/
return a1->original_order - a2->original_order;
}
/*
* Find the source address that will be used if trying to connect to the given
* address. src_addr must be large enough to hold a struct sockaddr_in6.
*
* Returns 1 if a source address was found, 0 if the address is unreachable,
* and -1 if a fatal error occurred. If 0 or 1, the contents of src_addr are
* undefined.
*/
/*ARGSUSED*/
static int
_find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr, unsigned mark)
{
int sock;
int ret;
socklen_t len;
switch (addr->sa_family) {
case AF_INET:
len = sizeof(struct sockaddr_in);
break;
case AF_INET6:
len = sizeof(struct sockaddr_in6);
break;
default:
/* No known usable source address for non-INET families. */
return 0;
}
sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
if (sock == -1) {
if (errno == EAFNOSUPPORT) {
return 0;
} else {
return -1;
}
}
if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
return 0;
do {
ret = connect(sock, addr, len);
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
close(sock);
return 0;
}
if (getsockname(sock, src_addr, &len) == -1) {
close(sock);
return -1;
}
close(sock);
return 1;
}
/*
* Sort the linked list starting at sentinel->ai_next in RFC6724 order.
* Will leave the list unchanged if an error occurs.
*/
/*ARGSUSED*/
static void
_rfc6724_sort(struct addrinfo *list_sentinel, unsigned mark)
{
struct addrinfo *cur;
int nelem = 0, i;
struct addrinfo_sort_elem *elems;
cur = list_sentinel->ai_next;
while (cur) {
++nelem;
cur = cur->ai_next;
}
elems = (struct addrinfo_sort_elem *)malloc(nelem * sizeof(struct addrinfo_sort_elem));
if (elems == NULL) {
goto error;
}
/*
* Convert the linked list to an array that also contains the candidate
* source address for each destination address.
*/
for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
int has_src_addr;
assert(cur != NULL);
elems[i].ai = cur;
elems[i].original_order = i;
has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.generic, mark);
if (has_src_addr == -1) {
goto error;
}
elems[i].has_src_addr = has_src_addr;
}
/* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
qsort((void *)elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare);
list_sentinel->ai_next = elems[0].ai;
for (i = 0; i < nelem - 1; ++i) {
elems[i].ai->ai_next = elems[i + 1].ai;
}
elems[nelem - 1].ai->ai_next = NULL;
error:
free(elems);
}
/*ARGSUSED*/
static int
_dns_getaddrinfo(void *rv, void *cb_data, va_list ap)
{
struct addrinfo *ai;
querybuf *buf, *buf2;
const char *name;
const struct addrinfo *pai;
struct addrinfo sentinel, *cur;
struct res_target q, q2;
res_state res;
unsigned netid, mark;
name = va_arg(ap, char *);
pai = va_arg(ap, const struct addrinfo *);
netid = va_arg(ap, unsigned);
mark = va_arg(ap, unsigned);
//fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name);
memset(&q, 0, sizeof(q));
memset(&q2, 0, sizeof(q2));
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
buf = malloc(sizeof(*buf));
if (buf == NULL) {
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
buf2 = malloc(sizeof(*buf2));
if (buf2 == NULL) {
free(buf);
h_errno = NETDB_INTERNAL;
return NS_NOTFOUND;
}
switch (pai->ai_family) {
case AF_UNSPEC:
/* prefer IPv6 */
q.name = name;
q.qclass = C_IN;
q.answer = buf->buf;
q.anslen = sizeof(buf->buf);
int query_ipv6 = 1, query_ipv4 = 1;
if (pai->ai_flags & AI_ADDRCONFIG) {
query_ipv6 = _have_ipv6(mark);
query_ipv4 = _have_ipv4(mark);
}
if (query_ipv6) {
q.qtype = T_AAAA;
if (query_ipv4) {
q.next = &q2;
q2.name = name;
q2.qclass = C_IN;
q2.qtype = T_A;
q2.answer = buf2->buf;
q2.anslen = sizeof(buf2->buf);
}
} else if (query_ipv4) {
q.qtype = T_A;
} else {
free(buf);
free(buf2);
return NS_NOTFOUND;
}
break;
case AF_INET:
q.name = name;
q.qclass = C_IN;
q.qtype = T_A;
q.answer = buf->buf;
q.anslen = sizeof(buf->buf);
break;
case AF_INET6:
q.name = name;
q.qclass = C_IN;
q.qtype = T_AAAA;
q.answer = buf->buf;
q.anslen = sizeof(buf->buf);
break;
default:
free(buf);
free(buf2);
return NS_UNAVAIL;
}
res = __res_get_state();
if (res == NULL) {
free(buf);
free(buf2);
return NS_NOTFOUND;
}
/* this just sets our netid val in the thread private data so we don't have to
* modify the api's all the way down to res_send.c's res_nsend. We could
* fully populate the thread private data here, but if we get down there
* and have a cache hit that would be wasted, so we do the rest there on miss
*/
res_setnetid(res, netid);
res_setmark(res, mark);
if (res_searchN(name, &q, res) < 0) {
__res_put_state(res);
free(buf);
free(buf2);
return NS_NOTFOUND;
}
ai = getanswer(buf, q.n, q.name, q.qtype, pai);
if (ai) {
cur->ai_next = ai;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
if (q.next) {
ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai);
if (ai)
cur->ai_next = ai;
}
free(buf);
free(buf2);
if (sentinel.ai_next == 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;
}
}
_rfc6724_sort(&sentinel, netid);
__res_put_state(res);
*((struct addrinfo **)rv) = sentinel.ai_next;
return NS_SUCCESS;
}
static void
_sethtent(FILE **hostf)
{
if (!*hostf)
*hostf = fopen(_PATH_HOSTS, "r" );
else
rewind(*hostf);
}
static void
_endhtent(FILE **hostf)
{
if (*hostf) {
(void) fclose(*hostf);
*hostf = NULL;
}
}
static struct addrinfo *
_gethtent(FILE **hostf, const char *name, const struct addrinfo *pai)
{
char *p;
char *cp, *tname, *cname;
struct addrinfo hints, *res0, *res;
int error;
const char *addr;
char hostbuf[8*1024];
// fprintf(stderr, "_gethtent() name = '%s'\n", name);
assert(name != NULL);
assert(pai != NULL);
if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "r" )))
return (NULL);
again:
if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf)))
return (NULL);
if (*p == '#')
goto again;
if (!(cp = strpbrk(p, "#\n")))
goto again;
*cp = '\0';
if (!(cp = strpbrk(p, " \t")))
goto again;
*cp++ = '\0';
addr = p;
/* if this is not something we're looking for, skip it. */
cname = NULL;
while (cp && *cp) {
if (*cp == ' ' || *cp == '\t') {
cp++;
continue;
}
if (!cname)
cname = cp;
tname = cp;
if ((cp = strpbrk(cp, " \t")) != NULL)
*cp++ = '\0';
// fprintf(stderr, "\ttname = '%s'", tname);
if (strcasecmp(name, tname) == 0)
goto found;
}
goto again;
found:
hints = *pai;
hints.ai_flags = AI_NUMERICHOST;
error = getaddrinfo(addr, NULL, &hints, &res0);
if (error)
goto again;
for (res = res0; res; res = res->ai_next) {
/* cover it up */
res->ai_flags = pai->ai_flags;
if (pai->ai_flags & AI_CANONNAME) {
if (get_canonname(pai, res, cname) != 0) {
freeaddrinfo(res0);
goto again;
}
}
}
return res0;
}
/*ARGSUSED*/
static int
_files_getaddrinfo(void *rv, void *cb_data, va_list ap)
{
const char *name;
const struct addrinfo *pai;
struct addrinfo sentinel, *cur;
struct addrinfo *p;
FILE *hostf = NULL;
name = va_arg(ap, char *);
pai = va_arg(ap, struct addrinfo *);
// fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
_sethtent(&hostf);
while ((p = _gethtent(&hostf, name, pai)) != NULL) {
cur->ai_next = p;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
_endhtent(&hostf);
*((struct addrinfo **)rv) = sentinel.ai_next;
if (sentinel.ai_next == NULL)
return NS_NOTFOUND;
return NS_SUCCESS;
}
/* resolver logic */
/*
* Formulate a normal query, send, and await answer.
* Returned answer is placed in supplied buffer "answer".
* Perform preliminary check of answer, returning success only
* if no error is indicated and the answer count is nonzero.
* Return the size of the response on success, -1 on error.
* Error number is left in h_errno.
*
* Caller must parse answer and determine whether it answers the question.
*/
static int
res_queryN(const char *name, /* domain name */ struct res_target *target,
res_state res)
{
u_char buf[MAXPACKET];
HEADER *hp;
int n;
struct res_target *t;
int rcode;
int ancount;
assert(name != NULL);
/* XXX: target may be NULL??? */
rcode = NOERROR;
ancount = 0;
for (t = target; t; t = t->next) {
int class, type;
u_char *answer;
int anslen;
hp = (HEADER *)(void *)t->answer;
hp->rcode = NOERROR; /* default */
/* make it easier... */
class = t->qclass;
type = t->qtype;
answer = t->answer;
anslen = t->anslen;
#ifdef DEBUG
if (res->options & RES_DEBUG)
printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
#endif
n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
buf, sizeof(buf));
#ifdef RES_USE_EDNS0
if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
n = res_nopt(res, n, buf, sizeof(buf), anslen);
#endif
if (n <= 0) {
#ifdef DEBUG
if (res->options & RES_DEBUG)
printf(";; res_nquery: mkquery failed\n");
#endif
h_errno = NO_RECOVERY;
return n;
}
n = res_nsend(res, buf, n, answer, anslen);
#if 0
if (n < 0) {
#ifdef DEBUG
if (res->options & RES_DEBUG)
printf(";; res_query: send error\n");
#endif
h_errno = TRY_AGAIN;
return n;
}
#endif
if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
rcode = hp->rcode; /* record most recent error */
#ifdef DEBUG
if (res->options & RES_DEBUG)
printf(";; rcode = %u, ancount=%u\n", hp->rcode,
ntohs(hp->ancount));
#endif
continue;
}
ancount += ntohs(hp->ancount);
t->n = n;
}
if (ancount == 0) {
switch (rcode) {
case NXDOMAIN:
h_errno = HOST_NOT_FOUND;
break;
case SERVFAIL:
h_errno = TRY_AGAIN;
break;
case NOERROR:
h_errno = NO_DATA;
break;
case FORMERR:
case NOTIMP:
case REFUSED:
default:
h_errno = NO_RECOVERY;
break;
}
return -1;
}
return ancount;
}
/*
* Formulate a normal query, send, and retrieve answer in supplied buffer.
* Return the size of the response on success, -1 on error.
* If enabled, implement search rules until answer or unrecoverable failure
* is detected. Error code, if any, is left in h_errno.
*/
static int
res_searchN(const char *name, struct res_target *target, res_state res)
{
const char *cp, * const *domain;
HEADER *hp;
u_int dots;
int trailing_dot, ret, saved_herrno;
int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
assert(name != NULL);
assert(target != NULL);
hp = (HEADER *)(void *)target->answer; /*XXX*/
errno = 0;
h_errno = HOST_NOT_FOUND; /* default, if we never query */
dots = 0;
for (cp = name; *cp; cp++)
dots += (*cp == '.');
trailing_dot = 0;
if (cp > name && *--cp == '.')
trailing_dot++;
//fprintf(stderr, "res_searchN() name = '%s'\n", name);
/*
* if there aren't any dots, it could be a user-level alias
*/
if (!dots && (cp = __hostalias(name)) != NULL) {
ret = res_queryN(cp, target, res);
return ret;
}
/*
* 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) {
ret = res_querydomainN(name, NULL, target, res);
if (ret > 0)
return (ret);
saved_herrno = h_errno;
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;
/* Unfortunately we need to set stuff up before
* the domain stuff is tried. Will have a better
* fix after thread pools are used.
*/
_resolv_populate_res_for_net(res);
for (domain = (const char * const *)res->dnsrch;
*domain && !done;
domain++) {
ret = res_querydomainN(name, *domain, target, res);
if (ret > 0)
return ret;
/*
* 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) {
h_errno = TRY_AGAIN;
return -1;
}
switch (h_errno) {
case NO_DATA:
got_nodata++;
/* FALLTHROUGH */
case HOST_NOT_FOUND:
/* keep trying */
break;
case TRY_AGAIN:
if (hp->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.
*/
if (!tried_as_is) {
ret = res_querydomainN(name, NULL, target, res);
if (ret > 0)
return ret;
}
/*
* 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)
h_errno = saved_herrno;
else if (got_nodata)
h_errno = NO_DATA;
else if (got_servfail)
h_errno = TRY_AGAIN;
return -1;
}
/*
* Perform a call on res_query on the concatenation of name and domain,
* removing a trailing dot from name if domain is NULL.
*/
static int
res_querydomainN(const char *name, const char *domain,
struct res_target *target, res_state res)
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
size_t n, d;
assert(name != NULL);
/* XXX: target may be NULL??? */
#ifdef DEBUG
if (res->options & RES_DEBUG)
printf(";; res_querydomain(%s, %s)\n",
name, domain?domain:"<Nil>");
#endif
if (domain == NULL) {
/*
* Check for trailing '.';
* copy without '.' if present.
*/
n = strlen(name);
if (n + 1 > sizeof(nbuf)) {
h_errno = NO_RECOVERY;
return -1;
}
if (n > 0 && name[--n] == '.') {
strncpy(nbuf, name, n);
nbuf[n] = '\0';
} else
longname = name;
} else {
n = strlen(name);
d = strlen(domain);
if (n + 1 + d + 1 > sizeof(nbuf)) {
h_errno = NO_RECOVERY;
return -1;
}
snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
}
return res_queryN(longname, target, res);
}
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