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getaddrinfo.c
2469 lines (2209 loc) · 60 KB
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getaddrinfo.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"
#include "private/bionic_defs.h"
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
#if defined(__ANDROID__)
// This should be synchronized to ResponseCode.h
static const int DnsProxyQueryResult = 222;
#endif
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 (8*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 **, const struct android_net_context *);
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 _find_src_addr(const struct sockaddr *, struct sockaddr *, unsigned , uid_t);
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)))
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
const char *
gai_strerror(int ecode)
{
if (ecode < 0 || ecode > EAI_MAX)
ecode = EAI_MAX;
return ai_errlist[ecode];
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
void
freeaddrinfo(struct addrinfo *ai)
{
struct addrinfo *next;
#if defined(__BIONIC__)
if (ai == NULL) return;
#else
_DIAGASSERT(ai != NULL);
#endif
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;
}
/*
* 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, uid_t uid) {
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 _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
}
static int
_have_ipv4(unsigned mark, uid_t uid) {
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 _find_src_addr(&addr.generic, NULL, mark, uid) == 1;
}
bool readBE32(FILE* fp, int32_t* result) {
int32_t tmp;
if (fread(&tmp, sizeof(tmp), 1, fp) != 1) {
return false;
}
*result = ntohl(tmp);
return true;
}
#if defined(__ANDROID__)
// 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 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;
}
FILE* proxy = fdopen(__netdClientDispatch.dnsOpenProxy(), "r+");
if (proxy == NULL) {
return EAI_SYSTEM;
}
netid = __netdClientDispatch.netIdForResolv(netid);
// Send the request.
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) {
int32_t have_more;
if (!readBE32(proxy, &have_more)) {
break;
}
if (have_more == 0) {
success = 1;
break;
}
struct addrinfo* ai = calloc(1, sizeof(struct addrinfo) + sizeof(struct sockaddr_storage));
if (ai == NULL) {
break;
}
ai->ai_addr = (struct sockaddr*)(ai + 1);
// struct addrinfo {
// int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */
// int ai_family; /* PF_xxx */
// int ai_socktype; /* SOCK_xxx */
// int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
// socklen_t ai_addrlen; /* length of ai_addr */
// char *ai_canonname; /* canonical name for hostname */
// struct sockaddr *ai_addr; /* binary address */
// struct addrinfo *ai_next; /* next structure in linked list */
// };
// Read the struct piece by piece because we might be a 32-bit process
// talking to a 64-bit netd.
int32_t addr_len;
bool success =
readBE32(proxy, &ai->ai_flags) &&
readBE32(proxy, &ai->ai_family) &&
readBE32(proxy, &ai->ai_socktype) &&
readBE32(proxy, &ai->ai_protocol) &&
readBE32(proxy, &addr_len);
if (!success) {
break;
}
// Set ai_addrlen and read the ai_addr data.
ai->ai_addrlen = addr_len;
if (addr_len != 0) {
if ((size_t) addr_len > sizeof(struct sockaddr_storage)) {
// Bogus; too big.
break;
}
if (fread(ai->ai_addr, addr_len, 1, proxy) != 1) {
break;
}
}
// The string for ai_cannonname.
int32_t name_len;
if (!readBE32(proxy, &name_len)) {
break;
}
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;
}
#endif
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
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);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int
android_getaddrinfofornet(const char *hostname, const char *servname,
const struct addrinfo *hints, unsigned netid, unsigned mark, struct addrinfo **res)
{
struct android_net_context netcontext = {
.app_netid = netid,
.app_mark = mark,
.dns_netid = netid,
.dns_mark = mark,
.uid = NET_CONTEXT_INVALID_UID,
};
return android_getaddrinfofornetcontext(hostname, servname, hints, &netcontext, res);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int
android_getaddrinfofornetcontext(const char *hostname, const char *servname,
const struct addrinfo *hints, const struct android_net_context *netcontext,
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;
/* hostname is allowed to be NULL */
/* servname is allowed to be NULL */
/* hints is allowed to be NULL */
assert(res != NULL);
assert(netcontext != 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);
#if defined(__ANDROID__)
int gai_error = android_getaddrinfo_proxy(
hostname, servname, hints, res, netcontext->app_netid);
if (gai_error != EAI_SYSTEM) {
return gai_error;
}
#endif
/*
* 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, netcontext);
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,
const struct android_net_context *netcontext)
{
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, netcontext)) {
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;
}