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|
/* resolv.c: DNS Resolver
*
* Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com>,
* The Silver Hammer Group, Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*/
/*
* Portions Copyright (c) 1985, 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.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/*
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* 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.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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.
*/
/*
*
* 5-Oct-2000 W. Greathouse wgreathouse@smva.com
* Fix memory leak and memory corruption.
* -- Every name resolution resulted in
* a new parse of resolv.conf and new
* copy of nameservers allocated by
* strdup.
* -- Every name resolution resulted in
* a new read of resolv.conf without
* resetting index from prior read...
* resulting in exceeding array bounds.
*
* Limit nameservers read from resolv.conf
*
* Add "search" domains from resolv.conf
*
* Some systems will return a security
* signature along with query answer for
* dynamic DNS entries.
* -- skip/ignore this answer
*
* Include arpa/nameser.h for defines.
*
* General cleanup
*
* 20-Jun-2001 Michal Moskal <malekith@pld.org.pl>
* partial IPv6 support (i.e. gethostbyname2() and resolve_address2()
* functions added), IPv6 nameservers are also supported.
*
* 6-Oct-2001 Jari Korva <jari.korva@iki.fi>
* more IPv6 support (IPv6 support for gethostbyaddr();
* address family parameter and improved IPv6 support for get_hosts_byname
* and read_etc_hosts; getnameinfo() port from glibc; defined
* defined ip6addr_any and in6addr_loopback)
*
* 2-Feb-2002 Erik Andersen <andersen@codepoet.org>
* Added gethostent(), sethostent(), and endhostent()
*
* 17-Aug-2002 Manuel Novoa III <mjn3@codepoet.org>
* Fixed __read_etc_hosts_r to return alias list, and modified buffer
* allocation accordingly. See MAX_ALIASES and ALIAS_DIM below.
* This fixes the segfault in the Python 2.2.1 socket test.
*
* 04-Jan-2003 Jay Kulpinski <jskulpin@berkshire.rr.com>
* Fixed __decode_dotted to count the terminating null character
* in a host name.
*
* 02-Oct-2003 Tony J. White <tjw@tjw.org>
* Lifted dn_expand() and dependent ns_name_uncompress(), ns_name_unpack(),
* and ns_name_ntop() from glibc 2.3.2 for compatibility with ipsec-tools
* and openldap.
*
* 7-Sep-2004 Erik Andersen <andersen@codepoet.org>
* Added gethostent_r()
*
*/
#define __FORCE_GLIBC
#include <features.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <resolv.h>
#include <netdb.h>
#include <ctype.h>
#include <stdbool.h>
#include <time.h>
#include <arpa/nameser.h>
#include <sys/utsname.h>
#include <sys/un.h>
#include <bits/uClibc_mutex.h>
/* poll() is not supported in kernel <= 2.0, therefore if __NR_poll is
* not available, we assume an old Linux kernel is in use and we will
* use select() instead. */
#include <sys/syscall.h>
#ifndef __NR_poll
# define USE_SELECT
#endif
/* Experimentally off - libc_hidden_proto(memcpy) */
/* Experimentally off - libc_hidden_proto(memset) */
/* Experimentally off - libc_hidden_proto(memmove) */
/* Experimentally off - libc_hidden_proto(strchr) */
/* Experimentally off - libc_hidden_proto(strcmp) */
/* Experimentally off - libc_hidden_proto(strcpy) */
/* Experimentally off - libc_hidden_proto(strdup) */
/* Experimentally off - libc_hidden_proto(strlen) */
/* Experimentally off - libc_hidden_proto(strncat) */
/* Experimentally off - libc_hidden_proto(strncpy) */
/* libc_hidden_proto(strnlen) */
/* Experimentally off - libc_hidden_proto(strstr) */
/* Experimentally off - libc_hidden_proto(strcasecmp) */
/* libc_hidden_proto(socket) */
/* libc_hidden_proto(close) */
/* libc_hidden_proto(fopen) */
/* libc_hidden_proto(fclose) */
/* libc_hidden_proto(random) */
/* libc_hidden_proto(getservbyport) */
/* libc_hidden_proto(gethostname) */
/* libc_hidden_proto(uname) */
/* libc_hidden_proto(inet_addr) */
/* libc_hidden_proto(inet_aton) */
/* libc_hidden_proto(inet_pton) */
/* libc_hidden_proto(inet_ntop) */
/* libc_hidden_proto(connect) */
/* libc_hidden_proto(poll) */
/* libc_hidden_proto(select) */
/* libc_hidden_proto(recv) */
/* libc_hidden_proto(send) */
/* libc_hidden_proto(printf) */
/* libc_hidden_proto(sprintf) */
/* libc_hidden_proto(snprintf) */
/* libc_hidden_proto(fgets) */
/* libc_hidden_proto(getnameinfo) */
/* libc_hidden_proto(gethostbyname) */
/* libc_hidden_proto(gethostbyname_r) */
/* libc_hidden_proto(gethostbyname2_r) */
/* libc_hidden_proto(gethostbyaddr) */
/* libc_hidden_proto(gethostbyaddr_r) */
/* libc_hidden_proto(ns_name_uncompress) */
/* libc_hidden_proto(ns_name_unpack) */
/* libc_hidden_proto(ns_name_ntop) */
/* libc_hidden_proto(res_init) */
/* libc_hidden_proto(res_query) */
/* libc_hidden_proto(res_querydomain) */
/* libc_hidden_proto(gethostent_r) */
/* libc_hidden_proto(fprintf) */
/* libc_hidden_proto(__h_errno_location) */
#ifdef __UCLIBC_HAS_XLOCALE__
/* libc_hidden_proto(__ctype_b_loc) */
#elif defined __UCLIBC_HAS_CTYPE_TABLES__
/* libc_hidden_proto(__ctype_b) */
#endif
#if defined __UCLIBC_HAS_IPV4__ && defined __UCLIBC_HAS_IPV6__
#define IF_HAS_BOTH(...) __VA_ARGS__
#else
#define IF_HAS_BOTH(...)
#endif
#define MAX_RECURSE 5
#define MAX_ALIASES 5
/* 1:ip + 1:full + MAX_ALIASES:aliases + 1:NULL */
#define ALIAS_DIM (2 + MAX_ALIASES + 1)
#undef DEBUG
/* #define DEBUG */
#ifdef DEBUG
#define DPRINTF(X,args...) fprintf(stderr, X, ##args)
#else
#define DPRINTF(X,args...)
#endif
#undef ARRAY_SIZE
#define ARRAY_SIZE(v) (sizeof(v) / sizeof((v)[0]))
/* Make sure the incoming char * buffer is aligned enough to handle our random
* structures. This define is the same as we use for malloc alignment (which
* has same requirements). The offset is the number of bytes we need to adjust
* in order to attain desired alignment.
*/
#define ALIGN_ATTR __alignof__(double __attribute_aligned__ (sizeof(size_t)))
#define ALIGN_BUFFER_OFFSET(buf) ((ALIGN_ATTR - ((size_t)buf % ALIGN_ATTR)) % ALIGN_ATTR)
/* Structs */
struct resolv_header {
int id;
int qr,opcode,aa,tc,rd,ra,rcode;
int qdcount;
int ancount;
int nscount;
int arcount;
};
struct resolv_question {
char * dotted;
int qtype;
int qclass;
};
struct resolv_answer {
char * dotted;
int atype;
int aclass;
int ttl;
int rdlength;
const unsigned char * rdata;
int rdoffset;
char* buf;
size_t buflen;
size_t add_count;
};
enum etc_hosts_action {
GET_HOSTS_BYNAME = 0,
GETHOSTENT,
GET_HOSTS_BYADDR,
};
typedef union sockaddr46_t {
struct sockaddr sa;
#ifdef __UCLIBC_HAS_IPV4__
struct sockaddr_in sa4;
#endif
#ifdef __UCLIBC_HAS_IPV6__
struct sockaddr_in6 sa6;
#endif
} sockaddr46_t;
__UCLIBC_MUTEX_EXTERN(__resolv_lock);
/* Protected by __resolv_lock */
extern void (*__res_sync)(void) attribute_hidden;
//extern uint32_t __resolv_opts attribute_hidden;
extern unsigned __nameservers attribute_hidden;
extern unsigned __searchdomains attribute_hidden;
extern sockaddr46_t *__nameserver attribute_hidden;
extern char **__searchdomain attribute_hidden;
#ifdef __UCLIBC_HAS_IPV4__
extern const struct sockaddr_in __local_nameserver attribute_hidden;
#else
extern const struct sockaddr_in6 __local_nameserver attribute_hidden;
#endif
/* Arbitrary */
#define MAXLEN_searchdomain 128
/* function prototypes */
extern int __get_hosts_byname_r(const char * name, int type,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop) attribute_hidden;
extern int __get_hosts_byaddr_r(const char * addr, int len, int type,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop) attribute_hidden;
extern FILE * __open_etc_hosts(void) attribute_hidden;
extern int __read_etc_hosts_r(FILE *fp, const char * name, int type,
enum etc_hosts_action action,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop) attribute_hidden;
extern int __dns_lookup(const char * name, int type,
unsigned char ** outpacket,
struct resolv_answer * a) attribute_hidden;
extern int __encode_dotted(const char * dotted, unsigned char * dest, int maxlen) attribute_hidden;
extern int __decode_dotted(const unsigned char * const message, int offset,
char * dest, int maxlen) attribute_hidden;
extern int __length_dotted(const unsigned char * const message, int offset) attribute_hidden;
extern int __encode_header(struct resolv_header * h, unsigned char * dest, int maxlen) attribute_hidden;
extern void __decode_header(unsigned char * data, struct resolv_header * h) attribute_hidden;
extern int __encode_question(const struct resolv_question * const q,
unsigned char * dest, int maxlen) attribute_hidden;
extern int __decode_question(const unsigned char * const message, int offset,
struct resolv_question * q) attribute_hidden;
extern int __encode_answer(struct resolv_answer * a,
unsigned char * dest, int maxlen) attribute_hidden;
extern int __decode_answer(const unsigned char * message, int offset,
int len, struct resolv_answer * a) attribute_hidden;
extern int __length_question(const unsigned char * const message, int offset) attribute_hidden;
extern void __open_nameservers(void) attribute_hidden;
extern void __close_nameservers(void) attribute_hidden;
extern int __dn_expand(const u_char *, const u_char *, const u_char *,
char *, int);
/*
* Theory of operation.
*
* gethostbyname, getaddrinfo and friends end up here, and they sometimes
* need to talk to DNS servers. In order to do this, we need to read /etc/resolv.conf
* and determine servers' addresses and the like. resolv.conf format:
*
* nameserver <IP[v6]>
* Address of DNS server. Cumulative.
* If not specified, assumed to be on localhost.
* search <domain1>[ <domain2>]...
* Append these domains to unqualified names.
* See ndots:n option.
* $LOCALDOMAIN (space-separated list) overrides this.
* domain <domain>
* Effectively same as "search" with one domain.
* If no "domain" line is present, the domain is determined
* from the local host name returned by gethostname();
* the domain part is taken to be everything after the first dot.
* If there are no dots, there will be no "domain".
* The domain and search keywords are mutually exclusive.
* If more than one instance of these keywords is present,
* the last instance wins.
* sortlist 130.155.160.0[/255.255.240.0] 130.155.0.0
* Allows addresses returned by gethostbyname to be sorted.
* Not supported.
* options option[ option]...
* (so far we support none)
* $RES_OPTIONS (space-separated list) is to be added to "options"
* debug sets RES_DEBUG in _res.options
* ndots:n how many dots there should be so that name will be tried
* first as an absolute name before any search list elements
* are appended to it. Default 1
* timeout:n how long to wait for response. Default 5
* (sun seems to have retrans:n synonym)
* attempts:n number of rounds to do before giving up and returning
* an error. Default 2
* (sun seems to have retry:n synonym)
* rotate sets RES_ROTATE in _res.options, round robin
* selection of nameservers. Otherwise try
* the first listed server first every time
* no-check-names
* sets RES_NOCHECKNAME in _res.options, which disables
* checking of incoming host names for invalid characters
* such as underscore (_), non-ASCII, or control characters
* inet6 sets RES_USE_INET6 in _res.options. Try a AAAA query
* before an A query inside the gethostbyname(), and map
* IPv4 responses in IPv6 "tunnelled form" if no AAAA records
* are found but an A record set exists
* no_tld_query (FreeBSDism?)
* do not attempt to resolve names without dots
*
* We will read and analyze /etc/resolv.conf as needed before
* we do a DNS request. This happens in __dns_lookup.
* (TODO: also re-parse it after a timeout, to catch updates).
*
* BSD has res_init routine which is used to initialize resolver state
* which is held in global structure _res.
* Generally, programs call res_init, then fiddle with _res.XXX
* (_res.options and _res.nscount, _res.nsaddr_list[N]
* are popular targets of fiddling) and expect subsequent calls
* to gethostbyname, getaddrinfo, etc to use modified information.
*
* However, historical _res structure is quite awkward.
* Using it for storing /etc/resolv.conf info is not desirable,
* and __dns_lookup does not use it.
*
* We would like to avoid using it unless absolutely necessary.
* If user doesn't use res_init, we should arrange it so that
* _res structure doesn't even *get linked in* into user's application
* (imagine static uclibc build here).
*
* The solution is a __res_sync function pointer, which is normally NULL.
* But if res_init is called, it gets set and any subsequent gethostbyname
* et al "syncronizes" our internal structures with potentially
* modified _res.XXX stuff by calling __res_sync.
* The trick here is that if res_init is not used and not linked in,
* gethostbyname itself won't reference _res and _res won't be linked in
* either. Other possible methods like
* if (__res_sync_just_an_int_flag)
* __sync_me_with_res()
* would pull in __sync_me_with_res, which pulls in _res. Bad.
*/
#ifdef L_encodeh
int attribute_hidden __encode_header(struct resolv_header *h, unsigned char *dest, int maxlen)
{
if (maxlen < HFIXEDSZ)
return -1;
dest[0] = (h->id & 0xff00) >> 8;
dest[1] = (h->id & 0x00ff) >> 0;
dest[2] = (h->qr ? 0x80 : 0) |
((h->opcode & 0x0f) << 3) |
(h->aa ? 0x04 : 0) |
(h->tc ? 0x02 : 0) |
(h->rd ? 0x01 : 0);
dest[3] = (h->ra ? 0x80 : 0) | (h->rcode & 0x0f);
dest[4] = (h->qdcount & 0xff00) >> 8;
dest[5] = (h->qdcount & 0x00ff) >> 0;
dest[6] = (h->ancount & 0xff00) >> 8;
dest[7] = (h->ancount & 0x00ff) >> 0;
dest[8] = (h->nscount & 0xff00) >> 8;
dest[9] = (h->nscount & 0x00ff) >> 0;
dest[10] = (h->arcount & 0xff00) >> 8;
dest[11] = (h->arcount & 0x00ff) >> 0;
return HFIXEDSZ;
}
#endif
#ifdef L_decodeh
void attribute_hidden __decode_header(unsigned char *data, struct resolv_header *h)
{
h->id = (data[0] << 8) | data[1];
h->qr = (data[2] & 0x80) ? 1 : 0;
h->opcode = (data[2] >> 3) & 0x0f;
h->aa = (data[2] & 0x04) ? 1 : 0;
h->tc = (data[2] & 0x02) ? 1 : 0;
h->rd = (data[2] & 0x01) ? 1 : 0;
h->ra = (data[3] & 0x80) ? 1 : 0;
h->rcode = data[3] & 0x0f;
h->qdcount = (data[4] << 8) | data[5];
h->ancount = (data[6] << 8) | data[7];
h->nscount = (data[8] << 8) | data[9];
h->arcount = (data[10] << 8) | data[11];
}
#endif
#ifdef L_encoded
/* Encode a dotted string into nameserver transport-level encoding.
This routine is fairly dumb, and doesn't attempt to compress
the data */
int attribute_hidden __encode_dotted(const char *dotted, unsigned char *dest, int maxlen)
{
unsigned used = 0;
while (dotted && *dotted) {
char *c = strchr(dotted, '.');
int l = c ? c - dotted : strlen(dotted);
/* two consecutive dots are not valid */
if (l == 0)
return -1;
if (l >= (maxlen - used - 1))
return -1;
dest[used++] = l;
memcpy(dest + used, dotted, l);
used += l;
if (!c)
break;
dotted = c + 1;
}
if (maxlen < 1)
return -1;
dest[used++] = 0;
return used;
}
#endif
#ifdef L_decoded
/* Decode a dotted string from nameserver transport-level encoding.
This routine understands compressed data. */
int attribute_hidden __decode_dotted(const unsigned char * const data, int offset,
char *dest, int maxlen)
{
int l;
bool measure = 1;
unsigned total = 0;
unsigned used = 0;
if (!data)
return -1;
while ((l = data[offset++])) {
if (measure)
total++;
if ((l & 0xc0) == (0xc0)) {
if (measure)
total++;
/* compressed item, redirect */
offset = ((l & 0x3f) << 8) | data[offset];
measure = 0;
continue;
}
if ((used + l + 1) >= maxlen)
return -1;
memcpy(dest + used, data + offset, l);
offset += l;
used += l;
if (measure)
total += l;
if (data[offset] != 0)
dest[used++] = '.';
else
dest[used++] = '\0';
}
/* The null byte must be counted too */
if (measure)
total++;
DPRINTF("Total decode len = %d\n", total);
return total;
}
#endif
#ifdef L_lengthd
/* Returns -1 only if data == NULL */
int attribute_hidden __length_dotted(const unsigned char * const data, int offset)
{
int orig_offset = offset;
int l;
if (!data)
return -1;
while ((l = data[offset++])) {
if ((l & 0xc0) == (0xc0)) {
offset++;
break;
}
offset += l;
}
return offset - orig_offset;
}
#endif
#ifdef L_encodeq
int attribute_hidden __encode_question(const struct resolv_question * const q,
unsigned char *dest, int maxlen)
{
int i;
i = __encode_dotted(q->dotted, dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
if (maxlen < 4)
return -1;
dest[0] = (q->qtype & 0xff00) >> 8;
dest[1] = (q->qtype & 0x00ff) >> 0;
dest[2] = (q->qclass & 0xff00) >> 8;
dest[3] = (q->qclass & 0x00ff) >> 0;
return i + 4;
}
#endif
#ifdef L_decodeq
int attribute_hidden __decode_question(const unsigned char * const message, int offset,
struct resolv_question *q)
{
char temp[256];
int i;
i = __decode_dotted(message, offset, temp, sizeof(temp));
if (i < 0)
return i;
offset += i;
//TODO: what if strdup fails?
q->dotted = strdup(temp);
q->qtype = (message[offset + 0] << 8) | message[offset + 1];
q->qclass = (message[offset + 2] << 8) | message[offset + 3];
return i + 4;
}
#endif
#ifdef L_lengthq
/* Returns -1 only if message == NULL */
int attribute_hidden __length_question(const unsigned char * const message, int offset)
{
int i;
/* returns -1 only if message == NULL */
i = __length_dotted(message, offset);
if (i < 0)
return i;
return i + 4;
}
#endif
#ifdef L_encodea
int attribute_hidden __encode_answer(struct resolv_answer *a, unsigned char *dest, int maxlen)
{
int i;
i = __encode_dotted(a->dotted, dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
if (maxlen < (RRFIXEDSZ + a->rdlength))
return -1;
*dest++ = (a->atype & 0xff00) >> 8;
*dest++ = (a->atype & 0x00ff) >> 0;
*dest++ = (a->aclass & 0xff00) >> 8;
*dest++ = (a->aclass & 0x00ff) >> 0;
*dest++ = (a->ttl & 0xff000000) >> 24;
*dest++ = (a->ttl & 0x00ff0000) >> 16;
*dest++ = (a->ttl & 0x0000ff00) >> 8;
*dest++ = (a->ttl & 0x000000ff) >> 0;
*dest++ = (a->rdlength & 0xff00) >> 8;
*dest++ = (a->rdlength & 0x00ff) >> 0;
memcpy(dest, a->rdata, a->rdlength);
return i + RRFIXEDSZ + a->rdlength;
}
#endif
#ifdef L_decodea
int attribute_hidden __decode_answer(const unsigned char *message, int offset,
int len, struct resolv_answer *a)
{
char temp[256];
int i;
DPRINTF("decode_answer(start): off %d, len %d\n", offset, len);
i = __decode_dotted(message, offset, temp, sizeof(temp));
if (i < 0)
return i;
message += offset + i;
len -= i + RRFIXEDSZ + offset;
if (len < 0) {
DPRINTF("decode_answer: off %d, len %d, i %d\n", offset, len, i);
return len;
}
// TODO: what if strdup fails?
a->dotted = strdup(temp);
a->atype = (message[0] << 8) | message[1];
message += 2;
a->aclass = (message[0] << 8) | message[1];
message += 2;
a->ttl = (message[0] << 24) |
(message[1] << 16) | (message[2] << 8) | (message[3] << 0);
message += 4;
a->rdlength = (message[0] << 8) | message[1];
message += 2;
a->rdata = message;
a->rdoffset = offset + i + RRFIXEDSZ;
DPRINTF("i=%d,rdlength=%d\n", i, a->rdlength);
if (len < a->rdlength)
return -1;
return i + RRFIXEDSZ + a->rdlength;
}
#endif
#ifdef CURRENTLY_UNUSED
#ifdef L_encodep
int __encode_packet(struct resolv_header *h,
struct resolv_question **q,
struct resolv_answer **an,
struct resolv_answer **ns,
struct resolv_answer **ar,
unsigned char *dest, int maxlen) attribute_hidden;
int __encode_packet(struct resolv_header *h,
struct resolv_question **q,
struct resolv_answer **an,
struct resolv_answer **ns,
struct resolv_answer **ar,
unsigned char *dest, int maxlen)
{
int i, total = 0;
unsigned j;
i = __encode_header(h, dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
total += i;
for (j = 0; j < h->qdcount; j++) {
i = __encode_question(q[j], dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
total += i;
}
for (j = 0; j < h->ancount; j++) {
i = __encode_answer(an[j], dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
total += i;
}
for (j = 0; j < h->nscount; j++) {
i = __encode_answer(ns[j], dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
total += i;
}
for (j = 0; j < h->arcount; j++) {
i = __encode_answer(ar[j], dest, maxlen);
if (i < 0)
return i;
dest += i;
maxlen -= i;
total += i;
}
return total;
}
#endif
#ifdef L_decodep
int __decode_packet(unsigned char *data, struct resolv_header *h) attribute_hidden;
int __decode_packet(unsigned char *data, struct resolv_header *h)
{
__decode_header(data, h);
return HFIXEDSZ;
}
#endif
#ifdef L_formquery
int __form_query(int id, const char *name, int type, unsigned char *packet, int maxlen);
int __form_query(int id, const char *name, int type, unsigned char *packet,
int maxlen)
{
struct resolv_header h;
struct resolv_question q;
int i, j;
memset(&h, 0, sizeof(h));
h.id = id;
h.qdcount = 1;
q.dotted = (char *) name;
q.qtype = type;
q.qclass = C_IN; /* CLASS_IN */
i = __encode_header(&h, packet, maxlen);
if (i < 0)
return i;
j = __encode_question(&q, packet + i, maxlen - i);
if (j < 0)
return j;
return i + j;
}
#endif
#endif /* CURRENTLY_UNUSED */
#ifdef L_opennameservers
# if __BYTE_ORDER == __LITTLE_ENDIAN
#define NAMESERVER_PORT_N (__bswap_constant_16(NAMESERVER_PORT))
#else
#define NAMESERVER_PORT_N NAMESERVER_PORT
#endif
__UCLIBC_MUTEX_INIT(__resolv_lock, PTHREAD_MUTEX_INITIALIZER);
/* Protected by __resolv_lock */
void (*__res_sync)(void);
//uint32_t __resolv_opts;
unsigned __nameservers;
unsigned __searchdomains;
sockaddr46_t *__nameserver;
char **__searchdomain;
#ifdef __UCLIBC_HAS_IPV4__
const struct sockaddr_in __local_nameserver = {
.sin_family = AF_INET,
.sin_port = NAMESERVER_PORT_N,
};
#else
const struct sockaddr_in6 __local_nameserver = {
.sin6_family = AF_INET6,
.sin6_port = NAMESERVER_PORT_N,
};
#endif
/* Helpers. Both stop on EOL, if it's '\n', it is converted to NUL first */
static char *skip_nospace(char *p)
{
while (*p != '\0' && !isspace(*p)) {
if (*p == '\n') {
*p = '\0';
break;
}
p++;
}
return p;
}
static char *skip_and_NUL_space(char *p)
{
/* NB: '\n' is not isspace! */
while (1) {
char c = *p;
if (c == '\0' || !isspace(c))
break;
*p = '\0';
if (c == '\n' || c == '#')
break;
p++;
}
return p;
}
/* Must be called under __resolv_lock. */
void attribute_hidden __open_nameservers(void)
{
static uint8_t last_time;
char szBuffer[MAXLEN_searchdomain];
FILE *fp;
int i;
sockaddr46_t sa;
if (!__res_sync) {
/* Provide for periodic reread of /etc/resolv.conf */
/* cur_time "ticks" every 256 seconds */
uint8_t cur_time = ((unsigned)time(NULL)) >> 8;
if (last_time != cur_time) {
last_time = cur_time;
__close_nameservers(); /* force config reread */
}
}
if (__nameservers)
goto sync;
fp = fopen("/etc/resolv.conf", "r");
if (!fp) {
// TODO: why? google says nothing about this...
fp = fopen("/etc/config/resolv.conf", "r");
}
if (fp) {
while (fgets(szBuffer, sizeof(szBuffer), fp) != NULL) {
void *ptr;
char *keyword, *p;
keyword = p = skip_and_NUL_space(szBuffer);
/* skip keyword */
p = skip_nospace(p);
/* find next word */
p = skip_and_NUL_space(p);
if (strcmp(keyword, "nameserver") == 0) {
/* terminate IP addr */
*skip_nospace(p) = '\0';
memset(&sa, 0, sizeof(sa));
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV6__
else if (inet_pton(AF_INET6, p, &sa.sa6.sin6_addr) > 0) {
sa.sa6.sin6_family = AF_INET6;
sa.sa6.sin6_port = htons(NAMESERVER_PORT);
}
#endif
#ifdef __UCLIBC_HAS_IPV4__
else if (inet_pton(AF_INET, p, &sa.sa4.sin_addr) > 0) {
sa.sa4.sin_family = AF_INET;
sa.sa4.sin_port = htons(NAMESERVER_PORT);
}
#endif
else
continue; /* garbage on this line */
ptr = realloc(__nameserver, (__nameservers + 1) * sizeof(__nameserver[0]));
if (!ptr)
continue;
__nameserver = ptr;
__nameserver[__nameservers++] = sa; /* struct copy */
continue;
}
if (strcmp(keyword, "domain") == 0 || strcmp(keyword, "search") == 0) {
char *p1;
/* free old domains ("last 'domain' or 'search' wins" rule) */
while (__searchdomains)
free(__searchdomain[--__searchdomains]);
/*free(__searchdomain);*/
/*__searchdomain = NULL; - not necessary */
next_word:
/* terminate current word */
p1 = skip_nospace(p);
/* find next word (maybe) */
p1 = skip_and_NUL_space(p1);
/* add it */
ptr = realloc(__searchdomain, (__searchdomains + 1) * sizeof(__searchdomain[0]));
if (!ptr)
continue;
__searchdomain = ptr;
/* NB: strlen(p) <= MAXLEN_searchdomain) because szBuffer[] is smaller */
ptr = strdup(p);
if (!ptr)
continue;
DPRINTF("adding search %s\n", (char*)ptr);
__searchdomain[__searchdomains++] = (char*)ptr;
p = p1;
if (*p)
goto next_word;
continue;
}
/* if (strcmp(keyword, "sortlist") == 0)... */
/* if (strcmp(keyword, "options") == 0)... */
}
fclose(fp);
}
if (__nameservers == 0) {
/* Have to handle malloc failure! What a mess...
* And it's not only here, we need to be careful
* to never write into __nameserver[0] if it points
* to constant __local_nameserver, or free it. */
__nameserver = malloc(sizeof(__nameserver[0]));
if (__nameserver)
memcpy(__nameserver, &__local_nameserver, sizeof(__local_nameserver));
else
__nameserver = (void*) &__local_nameserver;
__nameservers++;
}
if (__searchdomains == 0) {
char buf[256];
char *p;
i = gethostname(buf, sizeof(buf) - 1);
buf[sizeof(buf) - 1] = '\0';
if (i == 0 && (p = strchr(buf, '.')) != NULL && p[1]) {
p = strdup(p + 1);
if (!p)
goto err;
__searchdomain = malloc(sizeof(__searchdomain[0]));
if (!__searchdomain) {
free(p);
goto err;
}
__searchdomain[0] = p;
__searchdomains++;
err: ;
}
}
DPRINTF("nameservers = %d\n", __nameservers);
sync:
if (__res_sync)
__res_sync();
}
#endif
#ifdef L_closenameservers
/* Must be called under __resolv_lock. */
void attribute_hidden __close_nameservers(void)
{
if (__nameserver != (void*) &__local_nameserver)
free(__nameserver);
__nameserver = NULL;
__nameservers = 0;
while (__searchdomains)
free(__searchdomain[--__searchdomains]);
free(__searchdomain);
__searchdomain = NULL;
/*__searchdomains = 0; - already is */
}
#endif
#ifdef L_dnslookup
/* On entry:
* a.buf(len) = auxiliary buffer for IP addresses after first one
* a.add_count = how many additional addresses are there already
* outpacket = where to save ptr to raw packet? can be NULL
* On exit:
* ret < 0: error, all other data is not valid
* a.add_count & a.buf: updated
* a.rdlength: length of addresses (4 bytes for IPv4)
* *outpacket: updated (packet is malloced, you need to free it)
* a.rdata: points into *outpacket to 1st IP addr
* NB: don't pass outpacket == NULL if you need to use a.rdata!
* a.atype: type of query?
* a.dotted: which name we _actually_ used. May contain search domains
* appended. (why the filed is called "dotted" I have no idea)
* This is a malloced string. May be NULL because strdup failed.
*/
int attribute_hidden __dns_lookup(const char *name, int type,
unsigned char **outpacket,
struct resolv_answer *a)
{
/* Protected by __resolv_lock: */
static int last_ns_num = 0;
static uint16_t last_id = 1;
int i, j, len, fd, pos, rc;
int name_len;
#ifdef USE_SELECT
struct timeval tv;
fd_set fds;
#else
struct pollfd fds;
#endif
struct resolv_header h;
struct resolv_question q;
struct resolv_answer ma;
bool first_answer = 1;
int retries_left;
unsigned char *packet = malloc(PACKETSZ);
char *lookup;
int variant = -1; /* search domain to append, -1: none */
int local_ns_num = -1; /* Nth server to use */
int local_id = local_id; /* for compiler */
int sdomains;
bool ends_with_dot;
sockaddr46_t sa;
fd = -1;
lookup = NULL;
name_len = strlen(name);
if ((unsigned)name_len >= MAXDNAME - MAXLEN_searchdomain - 2)
goto fail; /* paranoia */
lookup = malloc(name_len + 1/*for '.'*/ + MAXLEN_searchdomain + 1);
if (!packet || !lookup || !name[0])
goto fail;
ends_with_dot = (name[name_len - 1] == '.');
/* no strcpy! paranoia, user might change name[] under us */
memcpy(lookup, name, name_len);
DPRINTF("Looking up type %d answer for '%s'\n", type, name);
retries_left = 0; /* for compiler */
do {
unsigned reply_timeout;
if (fd != -1) {
close(fd);
fd = -1;
}
/* Mess with globals while under lock */
/* NB: even data *pointed to* by globals may vanish
* outside the locks. We should assume any and all
* globals can completely change between locked
* code regions. OTOH, this is rare, so we don't need
* to handle it "nicely" (do not skip servers,
* search domains, etc), we only need to ensure
* we do not SEGV, use freed+overwritten data
* or do other Really Bad Things. */
__UCLIBC_MUTEX_LOCK(__resolv_lock);
__open_nameservers();
sdomains = __searchdomains;
lookup[name_len] = '\0';
if ((unsigned)variant < sdomains) {
/* lookup is name_len + 1 + MAXLEN_searchdomain + 1 long */
/* __searchdomain[] is not bigger than MAXLEN_searchdomain */
lookup[name_len] = '.';
strcpy(&lookup[name_len + 1], __searchdomain[variant]);
}
/* first time? pick starting server etc */
if (local_ns_num < 0) {
local_id = last_id;
//TODO: implement /etc/resolv.conf's "options rotate"
// (a.k.a. RES_ROTATE bit in _res.options)
// local_ns_num = 0;
// if (_res.options & RES_ROTATE)
local_ns_num = last_ns_num;
//TODO: use _res.retry
retries_left = __nameservers * RES_DFLRETRY;
}
retries_left--;
if (local_ns_num >= __nameservers)
local_ns_num = 0;
local_id++;
local_id &= 0xffff;
/* write new values back while still under lock */
last_id = local_id;
last_ns_num = local_ns_num;
/* struct copy */
/* can't just take a pointer, __nameserver[x]
* is not safe to use outside of locks */
sa = __nameserver[local_ns_num];
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
memset(packet, 0, PACKETSZ);
memset(&h, 0, sizeof(h));
/* encode header */
h.id = local_id;
h.qdcount = 1;
h.rd = 1;
DPRINTF("encoding header\n", h.rd);
i = __encode_header(&h, packet, PACKETSZ);
if (i < 0)
goto fail;
/* encode question */
DPRINTF("lookup name: %s\n", lookup);
q.dotted = lookup;
q.qtype = type;
q.qclass = C_IN; /* CLASS_IN */
j = __encode_question(&q, packet+i, PACKETSZ-i);
if (j < 0)
goto fail;
len = i + j;
/* send packet */
DPRINTF("On try %d, sending query to port %d\n",
retries_left, NAMESERVER_PORT);
fd = socket(sa.sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) /* paranoia */
goto try_next_server;
rc = connect(fd, &sa.sa, sizeof(sa));
if (rc < 0) {
//if (errno == ENETUNREACH) {
/* routing error, presume not transient */
goto try_next_server;
//}
//For example, what transient error this can be? Can't think of any
///* retry */
//continue;
}
DPRINTF("Xmit packet len:%d id:%d qr:%d\n", len, h.id, h.qr);
/* no error check - if it fails, we time out on recv */
send(fd, packet, len, 0);
#ifdef USE_SELECT
//TODO: use _res.retrans
reply_timeout = RES_TIMEOUT;
wait_again:
FD_ZERO(&fds);
FD_SET(fd, &fds);
tv.tv_sec = reply_timeout;
tv.tv_usec = 0;
if (select(fd + 1, &fds, NULL, NULL, &tv) <= 0) {
DPRINTF("Timeout\n");
/* timed out, so retry send and receive
* to next nameserver */
goto try_next_server;
}
reply_timeout--;
#else
reply_timeout = RES_TIMEOUT * 1000;
wait_again:
fds.fd = fd;
fds.events = POLLIN;
if (poll(&fds, 1, reply_timeout) <= 0) {
DPRINTF("Timeout\n");
/* timed out, so retry send and receive
* to next nameserver */
goto try_next_server;
}
//TODO: better timeout accounting?
reply_timeout -= 1000;
#endif
len = recv(fd, packet, PACKETSZ, MSG_DONTWAIT);
if (len < HFIXEDSZ) {
/* too short!
* it's just a bogus packet from somewhere */
bogus_packet:
if (reply_timeout)
goto wait_again;
goto try_next_server;
}
__decode_header(packet, &h);
DPRINTF("id = %d, qr = %d\n", h.id, h.qr);
if (h.id != local_id || !h.qr) {
/* unsolicited */
goto bogus_packet;
}
DPRINTF("Got response (i think)!\n");
DPRINTF("qrcount=%d,ancount=%d,nscount=%d,arcount=%d\n",
h.qdcount, h.ancount, h.nscount, h.arcount);
DPRINTF("opcode=%d,aa=%d,tc=%d,rd=%d,ra=%d,rcode=%d\n",
h.opcode, h.aa, h.tc, h.rd, h.ra, h.rcode);
/* bug 660 says we treat negative response as an error
* and retry, which is, eh, an error. :)
* We were incurring long delays because of this. */
if (h.rcode == NXDOMAIN) {
/* if possible, try next search domain */
if (!ends_with_dot) {
DPRINTF("variant:%d sdomains:%d\n", variant, sdomains);
if (variant < sdomains - 1) {
/* next search domain */
variant++;
continue;
}
/* no more search domains to try */
}
/* dont loop, this is "no such host" situation */
h_errno = HOST_NOT_FOUND;
goto fail1;
}
/* Insert other non-fatal errors here, which do not warrant
* switching to next nameserver */
/* Strange error, assuming this nameserver is feeling bad */
if (h.rcode != 0)
goto try_next_server;
/* Code below won't work correctly with h.ancount == 0, so... */
if (h.ancount <= 0) {
h_errno = NO_DATA; /* is this correct code? */
goto fail1;
}
pos = HFIXEDSZ;
for (j = 0; j < h.qdcount; j++) {
DPRINTF("Skipping question %d at %d\n", j, pos);
/* returns -1 only if packet == NULL (can't happen) */
i = __length_question(packet, pos);
DPRINTF("Length of question %d is %d\n", j, i);
pos += i;
}
DPRINTF("Decoding answer at pos %d\n", pos);
first_answer = 1;
for (j = 0; j < h.ancount && pos < len; j++) {
i = __decode_answer(packet, pos, len, &ma);
if (i < 0) {
DPRINTF("failed decode %d\n", i);
/* If the message was truncated but we have
* decoded some answers, pretend it's OK */
if (j && h.tc)
break;
goto try_next_server;
}
pos += i;
if (first_answer) {
ma.buf = a->buf;
ma.buflen = a->buflen;
ma.add_count = a->add_count;
memcpy(a, &ma, sizeof(ma));
if (a->atype != T_SIG && (NULL == a->buf || (type != T_A && type != T_AAAA)))
break;
if (a->atype != type) {
free(a->dotted);
continue;
}
a->add_count = h.ancount - j - 1;
if ((a->rdlength + sizeof(struct in_addr*)) * a->add_count > a->buflen)
break;
a->add_count = 0;
first_answer = 0;
} else {
free(ma.dotted);
if (ma.atype != type)
continue;
if (a->rdlength != ma.rdlength) {
free(a->dotted);
DPRINTF("Answer address len(%u) differs from original(%u)\n",
ma.rdlength, a->rdlength);
goto try_next_server;
}
memcpy(a->buf + (a->add_count * ma.rdlength), ma.rdata, ma.rdlength);
++a->add_count;
}
}
/* Success! */
DPRINTF("Answer name = |%s|\n", a->dotted);
DPRINTF("Answer type = |%d|\n", a->atype);
if (fd != -1)
close(fd);
if (outpacket)
*outpacket = packet;
else
free(packet);
free(lookup);
return len;
try_next_server:
/* Try next nameserver */
local_ns_num++;
variant = -1;
} while (retries_left > 0);
fail:
h_errno = NETDB_INTERNAL;
fail1:
if (fd != -1)
close(fd);
free(lookup);
free(packet);
return -1;
}
#endif
#ifdef L_read_etc_hosts_r
FILE * __open_etc_hosts(void)
{
FILE * fp;
if ((fp = fopen("/etc/hosts", "r")) == NULL) {
fp = fopen("/etc/config/hosts", "r");
}
return fp;
}
int attribute_hidden __read_etc_hosts_r(
FILE * fp,
const char * name,
int type,
enum etc_hosts_action action,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop)
{
struct in_addr **addr_list = NULL;
struct in_addr *in = NULL;
char *cp, **alias;
int aliases, i, ret = HOST_NOT_FOUND;
*h_errnop = NETDB_INTERNAL;
/* make sure pointer is aligned */
i = ALIGN_BUFFER_OFFSET(buf);
buf += i;
buflen -= i;
/* Layout in buf:
* char *alias[ALIAS_DIM];
* struct in[6]_addr* addr_list[2];
* struct in[6]_addr* in;
* char line_buffer[80+];
*/
#define in6 ((struct in6_addr *)in)
alias = (char **)buf;
buf += sizeof(char **) * ALIAS_DIM;
buflen -= sizeof(char **) * ALIAS_DIM;
if ((ssize_t)buflen < 0)
return ERANGE;
if (action != GETHOSTENT) {
addr_list = (struct in_addr**)buf;
buf += sizeof(*addr_list) * 2;
buflen -= sizeof(*addr_list) * 2;
in = (struct in_addr*)buf;
#ifndef __UCLIBC_HAS_IPV6__
buf += sizeof(*in);
buflen -= sizeof(*in);
#else
buf += sizeof(*in6);
buflen -= sizeof(*in6);
#endif
if ((ssize_t)buflen < 80)
return ERANGE;
fp = __open_etc_hosts();
if (fp == NULL) {
*result = NULL;
return errno;
}
}
addr_list[0] = in;
addr_list[1] = NULL;
*h_errnop = HOST_NOT_FOUND;
while (fgets(buf, buflen, fp)) {
*strchrnul(buf, '#') = '\0';
DPRINTF("Looking at: %s\n", buf);
aliases = 0;
cp = buf;
while (*cp) {
while (*cp && isspace(*cp))
*cp++ = '\0';
if (!*cp)
break;
if (aliases < (2 + MAX_ALIASES))
alias[aliases++] = cp;
while (*cp && !isspace(*cp))
cp++;
}
alias[aliases] = NULL;
if (aliases < 2)
continue; /* syntax error really */
if (action == GETHOSTENT) {
/* Return whatever the next entry happens to be. */
break;
}
if (action == GET_HOSTS_BYADDR) {
if (strcmp(name, alias[0]) != 0)
continue;
} else {
/* GET_HOSTS_BYNAME */
for (i = 1; i < aliases; i++)
if (strcasecmp(name, alias[i]) == 0)
goto found;
continue;
found: ;
}
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV4__
else if (type == AF_INET && inet_pton(AF_INET, alias[0], in) > 0) {
DPRINTF("Found INET\n");
result_buf->h_addrtype = AF_INET;
result_buf->h_length = sizeof(*in);
result_buf->h_name = alias[1];
result_buf->h_addr_list = (char**) addr_list;
result_buf->h_aliases = alias + 2;
*result = result_buf;
ret = NETDB_SUCCESS;
}
#endif
#ifdef __UCLIBC_HAS_IPV6__
else if (type == AF_INET6 && inet_pton(AF_INET6, alias[0], in6) > 0) {
DPRINTF("Found INET6\n");
result_buf->h_addrtype = AF_INET6;
result_buf->h_length = sizeof(*in6);
result_buf->h_name = alias[1];
result_buf->h_addr_list = (char**) addr_list;
result_buf->h_aliases = alias + 2;
*result = result_buf;
ret = NETDB_SUCCESS;
}
#endif
else {
/* continue parsing in the hope the user has multiple
* host types listed in the database like so:
* <ipv4 addr> host
* <ipv6 addr> host
* If looking for an IPv6 addr, don't bail when we got the IPv4
*/
DPRINTF("Error: Found host but diff network type\n");
/* NB: gethostbyname2_r depends on this feature
* to avoid looking for IPv6 addr of "localhost" etc */
ret = TRY_AGAIN;
continue;
}
break;
}
if (action != GETHOSTENT)
fclose(fp);
return ret;
#undef in6
}
#endif
#ifdef L_get_hosts_byname_r
int attribute_hidden __get_hosts_byname_r(const char * name, int type,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop)
{
return __read_etc_hosts_r(NULL, name, type, GET_HOSTS_BYNAME,
result_buf, buf, buflen, result, h_errnop);
}
#endif
#ifdef L_get_hosts_byaddr_r
int attribute_hidden __get_hosts_byaddr_r(const char * addr, int len, int type,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop)
{
#ifndef __UCLIBC_HAS_IPV6__
char ipaddr[INET_ADDRSTRLEN];
#else
char ipaddr[INET6_ADDRSTRLEN];
#endif
switch (type) {
#ifdef __UCLIBC_HAS_IPV4__
case AF_INET:
if (len != sizeof(struct in_addr))
return 0;
break;
#endif
#ifdef __UCLIBC_HAS_IPV6__
case AF_INET6:
if (len != sizeof(struct in6_addr))
return 0;
break;
#endif
default:
return 0;
}
inet_ntop(type, addr, ipaddr, sizeof(ipaddr));
return __read_etc_hosts_r(NULL, ipaddr, type, GET_HOSTS_BYADDR,
result_buf, buf, buflen, result, h_errnop);
}
#endif
#ifdef L_getnameinfo
int getnameinfo(const struct sockaddr *sa, socklen_t addrlen, char *host,
socklen_t hostlen, char *serv, socklen_t servlen,
unsigned int flags)
{
int serrno = errno;
unsigned ok;
struct hostent *h = NULL;
char domain[256];
if (flags & ~(NI_NUMERICHOST|NI_NUMERICSERV|NI_NOFQDN|NI_NAMEREQD|NI_DGRAM))
return EAI_BADFLAGS;
if (sa == NULL || addrlen < sizeof(sa_family_t))
return EAI_FAMILY;
ok = sa->sa_family;
if (ok == AF_LOCAL) /* valid */;
#ifdef __UCLIBC_HAS_IPV4__
else if (ok == AF_INET) {
if (addrlen < sizeof(struct sockaddr_in))
return EAI_FAMILY;
}
#endif
#ifdef __UCLIBC_HAS_IPV6__
else if (ok == AF_INET6) {
if (addrlen < sizeof(struct sockaddr_in6))
return EAI_FAMILY;
}
#endif
else
return EAI_FAMILY;
ok = 0;
if (host != NULL && hostlen > 0)
switch (sa->sa_family) {
case AF_INET:
#ifdef __UCLIBC_HAS_IPV6__
case AF_INET6:
#endif
if (!(flags & NI_NUMERICHOST)) {
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV6__
else if (sa->sa_family == AF_INET6)
h = gethostbyaddr((const void *)
&(((const struct sockaddr_in6 *) sa)->sin6_addr),
sizeof(struct in6_addr), AF_INET6);
#endif
#ifdef __UCLIBC_HAS_IPV4__
else
h = gethostbyaddr((const void *)
&(((const struct sockaddr_in *)sa)->sin_addr),
sizeof(struct in_addr), AF_INET);
#endif
if (h) {
char *c;
#undef min
#define min(x,y) (((x) > (y)) ? (y) : (x))
if ((flags & NI_NOFQDN)
&& (getdomainname(domain, sizeof(domain)) == 0)
&& (c = strstr(h->h_name, domain)) != NULL
&& (c != h->h_name) && (*(--c) == '.')
) {
strncpy(host, h->h_name,
min(hostlen, (size_t) (c - h->h_name)));
host[min(hostlen - 1, (size_t) (c - h->h_name))] = '\0';
} else {
strncpy(host, h->h_name, hostlen);
}
ok = 1;
#undef min
}
}
if (!ok) {
const char *c = NULL;
if (flags & NI_NAMEREQD) {
errno = serrno;
return EAI_NONAME;
}
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV6__
else if (sa->sa_family == AF_INET6) {
const struct sockaddr_in6 *sin6p;
sin6p = (const struct sockaddr_in6 *) sa;
c = inet_ntop(AF_INET6,
(const void *) &sin6p->sin6_addr,
host, hostlen);
#if 0
/* Does scope id need to be supported? */
uint32_t scopeid;
scopeid = sin6p->sin6_scope_id;
if (scopeid != 0) {
/* Buffer is >= IFNAMSIZ+1. */
char scopebuf[IFNAMSIZ + 1];
char *scopeptr;
int ni_numericscope = 0;
size_t real_hostlen = strnlen(host, hostlen);
size_t scopelen = 0;
scopebuf[0] = SCOPE_DELIMITER;
scopebuf[1] = '\0';
scopeptr = &scopebuf[1];
if (IN6_IS_ADDR_LINKLOCAL(&sin6p->sin6_addr)
|| IN6_IS_ADDR_MC_LINKLOCAL(&sin6p->sin6_addr)) {
if (if_indextoname(scopeid, scopeptr) == NULL)
++ni_numericscope;
else
scopelen = strlen(scopebuf);
} else {
++ni_numericscope;
}
if (ni_numericscope)
scopelen = 1 + snprintf(scopeptr,
(scopebuf
+ sizeof scopebuf
- scopeptr),
"%u", scopeid);
if (real_hostlen + scopelen + 1 > hostlen)
return EAI_SYSTEM;
memcpy(host + real_hostlen, scopebuf, scopelen + 1);
}
#endif
}
#endif /* __UCLIBC_HAS_IPV6__ */
#if defined __UCLIBC_HAS_IPV4__
else {
c = inet_ntop(AF_INET, (const void *)
&(((const struct sockaddr_in *) sa)->sin_addr),
host, hostlen);
}
#endif
if (c == NULL) {
errno = serrno;
return EAI_SYSTEM;
}
ok = 1;
}
break;
case AF_LOCAL:
if (!(flags & NI_NUMERICHOST)) {
struct utsname utsname;
if (!uname(&utsname)) {
strncpy(host, utsname.nodename, hostlen);
break;
};
};
if (flags & NI_NAMEREQD) {
errno = serrno;
return EAI_NONAME;
}
strncpy(host, "localhost", hostlen);
break;
/* Already checked above
default:
return EAI_FAMILY;
*/
}
if (serv && (servlen > 0)) {
if (sa->sa_family == AF_LOCAL) {
strncpy(serv, ((const struct sockaddr_un *) sa)->sun_path, servlen);
} else { /* AF_INET || AF_INET6 */
if (!(flags & NI_NUMERICSERV)) {
struct servent *s;
s = getservbyport(((const struct sockaddr_in *) sa)->sin_port,
((flags & NI_DGRAM) ? "udp" : "tcp"));
if (s) {
strncpy(serv, s->s_name, servlen);
goto DONE;
}
}
snprintf(serv, servlen, "%d",
ntohs(((const struct sockaddr_in *) sa)->sin_port));
}
}
DONE:
if (host && (hostlen > 0))
host[hostlen-1] = 0;
if (serv && (servlen > 0))
serv[servlen-1] = 0;
errno = serrno;
return 0;
}
libc_hidden_def(getnameinfo)
#endif
#ifdef L_gethostbyname_r
//Does this function assume IPv4? If yes,
//what happens in IPv6-only build?
/* Bug 671 says:
* "uClibc resolver's gethostbyname does not return the requested name
* as an alias, but instead returns the canonical name. glibc's
* gethostbyname has a similar bug where it returns the requested name
* with the search domain name appended (to make a FQDN) as an alias,
* but not the original name itself. Both contradict POSIX, which says
* that the name argument passed to gethostbyname must be in the alias list"
* This is fixed now, and we differ from glibc:
*
* $ ./gethostbyname_uclibc wer.google.com
* h_name:'c13-ss-2-lb.cnet.com'
* h_length:4
* h_addrtype:2 AF_INET
* alias:'wer.google.com' <===
* addr: 0x4174efd8 '216.239.116.65'
*
* $ ./gethostbyname_glibc wer.google.com
* h_name:'c13-ss-2-lb.cnet.com'
* h_length:4
* h_addrtype:2 AF_INET
* alias:'wer.google.com.com' <===
* addr:'216.239.116.65'
*
* When examples were run, /etc/resolv.conf contained "search com" line.
*/
int gethostbyname_r(const char * name,
struct hostent * result_buf,
char * buf,
size_t buflen,
struct hostent ** result,
int * h_errnop)
{
struct in_addr **addr_list;
char **alias;
char *alias0;
unsigned char *packet;
struct resolv_answer a;
int i;
int wrong_af = 0;
*result = NULL;
if (!name)
return EINVAL;
/* do /etc/hosts first */
{
int old_errno = errno; /* save the old errno and reset errno */
__set_errno(0); /* to check for missing /etc/hosts. */
i = __get_hosts_byname_r(name, AF_INET, result_buf,
buf, buflen, result, h_errnop);
if (i == NETDB_SUCCESS) {
__set_errno(old_errno);
return i;
}
switch (*h_errnop) {
case HOST_NOT_FOUND:
wrong_af = (i == TRY_AGAIN);
case NO_ADDRESS:
break;
case NETDB_INTERNAL:
if (errno == ENOENT) {
break;
}
/* else fall through */
default:
return i;
}
__set_errno(old_errno);
}
DPRINTF("Nothing found in /etc/hosts\n");
*h_errnop = NETDB_INTERNAL;
/* prepare future h_aliases[0] */
i = strlen(name) + 1;
if ((ssize_t)buflen <= i)
return ERANGE;
memcpy(buf, name, i); /* paranoia: name might change */
alias0 = buf;
buf += i;
buflen -= i;
/* make sure pointer is aligned */
i = ALIGN_BUFFER_OFFSET(buf);
buf += i;
buflen -= i;
/* Layout in buf:
* char *alias[2];
* struct in_addr* addr_list[NN+1];
* struct in_addr* in[NN];
*/
alias = (char **)buf;
buf += sizeof(alias[0]) * 2;
buflen -= sizeof(alias[0]) * 2;
addr_list = (struct in_addr **)buf;
/* buflen may be < 0, must do signed compare */
if ((ssize_t)buflen < 256)
return ERANGE;
/* we store only one "alias" - the name itself */
#ifdef __UCLIBC_MJN3_ONLY__
#warning TODO -- generate the full list
#endif
alias[0] = alias0;
alias[1] = NULL;
/* maybe it is already an address? */
{
struct in_addr *in = (struct in_addr *)(buf + sizeof(addr_list[0]) * 2);
if (inet_aton(name, in)) {
addr_list[0] = in;
addr_list[1] = NULL;
result_buf->h_name = alias0;
result_buf->h_aliases = alias;
result_buf->h_addrtype = AF_INET;
result_buf->h_length = sizeof(struct in_addr);
result_buf->h_addr_list = (char **) addr_list;
*result = result_buf;
*h_errnop = NETDB_SUCCESS;
return NETDB_SUCCESS;
}
}
/* what if /etc/hosts has it but it's not IPv4?
* F.e. "::1 localhost6". We don't do DNS query for such hosts -
* "ping localhost6" should be fast even if DNS server is down! */
if (wrong_af) {
*h_errnop = HOST_NOT_FOUND;
return TRY_AGAIN;
}
/* talk to DNS servers */
a.buf = buf;
/* take into account that at least one address will be there,
* we'll need space of one in_addr + two addr_list[] elems */
a.buflen = buflen - ((sizeof(addr_list[0]) * 2 + sizeof(struct in_addr)));
a.add_count = 0;
i = __dns_lookup(name, T_A, &packet, &a);
if (i < 0) {
*h_errnop = HOST_NOT_FOUND;
DPRINTF("__dns_lookup returned < 0\n");
return TRY_AGAIN;
}
if (a.atype == T_A) { /* ADDRESS */
/* we need space for addr_list[] and one IPv4 address */
/* + 1 accounting for 1st addr (it's in a.rdata),
* another + 1 for NULL in last addr_list[]: */
int need_bytes = sizeof(addr_list[0]) * (a.add_count + 1 + 1)
/* for 1st addr (it's in a.rdata): */
+ sizeof(struct in_addr);
/* how many bytes will 2nd and following addresses take? */
int ips_len = a.add_count * a.rdlength;
buflen -= (need_bytes + ips_len);
if ((ssize_t)buflen < 0) {
DPRINTF("buffer too small for all addresses\n");
/* *h_errnop = NETDB_INTERNAL; - already is */
i = ERANGE;
goto free_and_ret;
}
/* if there are additional addresses in buf,
* move them forward so that they are not destroyed */
DPRINTF("a.add_count:%d a.rdlength:%d a.rdata:%p\n", a.add_count, a.rdlength, a.rdata);
memmove(buf + need_bytes, buf, ips_len);
/* 1st address is in a.rdata, insert it */
buf += need_bytes - sizeof(struct in_addr);
memcpy(buf, a.rdata, sizeof(struct in_addr));
/* fill addr_list[] */
for (i = 0; i <= a.add_count; i++) {
addr_list[i] = (struct in_addr*)buf;
buf += sizeof(struct in_addr);
}
addr_list[i] = NULL;
/* if we have enough space, we can report "better" name
* (it may contain search domains attached by __dns_lookup,
* or CNAME of the host if it is different from the name
* we used to find it) */
if (a.dotted && buflen > strlen(a.dotted)) {
strcpy(buf, a.dotted);
alias0 = buf;
}
result_buf->h_name = alias0;
result_buf->h_aliases = alias;
result_buf->h_addrtype = AF_INET;
result_buf->h_length = sizeof(struct in_addr);
result_buf->h_addr_list = (char **) addr_list;
*result = result_buf;
*h_errnop = NETDB_SUCCESS;
i = NETDB_SUCCESS;
goto free_and_ret;
}
*h_errnop = HOST_NOT_FOUND;
i = TRY_AGAIN;
free_and_ret:
free(a.dotted);
free(packet);
return i;
}
libc_hidden_def(gethostbyname_r)
#endif
#ifdef L_gethostbyname2_r
int gethostbyname2_r(const char *name,
int family,
struct hostent * result_buf,
char * buf,
size_t buflen,
struct hostent ** result,
int * h_errnop)
{
#ifndef __UCLIBC_HAS_IPV6__
return family == (AF_INET)
? gethostbyname_r(name, result_buf, buf, buflen, result, h_errnop)
: HOST_NOT_FOUND;
#else
struct in6_addr *in;
struct in6_addr **addr_list;
unsigned char *packet;
struct resolv_answer a;
int i;
int nest = 0;
int wrong_af = 0;
if (family == AF_INET)
return gethostbyname_r(name, result_buf, buf, buflen, result, h_errnop);
*result = NULL;
if (family != AF_INET6)
return EINVAL;
if (!name)
return EINVAL;
/* do /etc/hosts first */
{
int old_errno = errno; /* Save the old errno and reset errno */
__set_errno(0); /* to check for missing /etc/hosts. */
i = __get_hosts_byname_r(name, AF_INET6 /*family*/, result_buf,
buf, buflen, result, h_errnop);
if (i == NETDB_SUCCESS) {
__set_errno(old_errno);
return i;
}
switch (*h_errnop) {
case HOST_NOT_FOUND:
wrong_af = (i == TRY_AGAIN);
case NO_ADDRESS:
break;
case NETDB_INTERNAL:
if (errno == ENOENT) {
break;
}
/* else fall through */
default:
return i;
}
__set_errno(old_errno);
}
DPRINTF("Nothing found in /etc/hosts\n");
*h_errnop = NETDB_INTERNAL;
/* make sure pointer is aligned */
i = ALIGN_BUFFER_OFFSET(buf);
buf += i;
buflen -= i;
/* Layout in buf:
* struct in6_addr* in;
* struct in6_addr* addr_list[2];
* char scratch_buf[256];
*/
in = (struct in6_addr*)buf;
buf += sizeof(*in);
buflen -= sizeof(*in);
addr_list = (struct in6_addr**)buf;
buf += sizeof(*addr_list) * 2;
buflen -= sizeof(*addr_list) * 2;
if ((ssize_t)buflen < 256)
return ERANGE;
addr_list[0] = in;
addr_list[1] = NULL;
strncpy(buf, name, buflen);
buf[buflen] = '\0';
/* maybe it is already an address? */
if (inet_pton(AF_INET6, name, in)) {
result_buf->h_name = buf;
result_buf->h_addrtype = AF_INET6;
result_buf->h_length = sizeof(*in);
result_buf->h_addr_list = (char **) addr_list;
//result_buf->h_aliases = ???
*result = result_buf;
*h_errnop = NETDB_SUCCESS;
return NETDB_SUCCESS;
}
/* what if /etc/hosts has it but it's not IPv6?
* F.e. "127.0.0.1 localhost". We don't do DNS query for such hosts -
* "ping localhost" should be fast even if DNS server is down! */
if (wrong_af) {
*h_errnop = HOST_NOT_FOUND;
return TRY_AGAIN;
}
/* talk to DNS servers */
// TODO: why it's so different from gethostbyname_r (IPv4 case)?
memset(&a, '\0', sizeof(a));
for (;;) {
// Hmm why we memset(a) to zeros only once?
i = __dns_lookup(buf, T_AAAA, &packet, &a);
if (i < 0) {
*h_errnop = HOST_NOT_FOUND;
return TRY_AGAIN;
}
strncpy(buf, a.dotted, buflen);
free(a.dotted);
if (a.atype != T_CNAME)
break;
DPRINTF("Got a CNAME in gethostbyname()\n");
if (++nest > MAX_RECURSE) {
*h_errnop = NO_RECOVERY;
return -1;
}
i = __decode_dotted(packet, a.rdoffset, buf, buflen);
free(packet);
if (i < 0) {
*h_errnop = NO_RECOVERY;
return -1;
}
}
if (a.atype == T_AAAA) { /* ADDRESS */
memcpy(in, a.rdata, sizeof(*in));
result_buf->h_name = buf;
result_buf->h_addrtype = AF_INET6;
result_buf->h_length = sizeof(*in);
result_buf->h_addr_list = (char **) addr_list;
//result_buf->h_aliases = ???
free(packet);
*result = result_buf;
*h_errnop = NETDB_SUCCESS;
return NETDB_SUCCESS;
}
free(packet);
*h_errnop = HOST_NOT_FOUND;
return TRY_AGAIN;
#endif /* __UCLIBC_HAS_IPV6__ */
}
libc_hidden_def(gethostbyname2_r)
#endif
#ifdef L_gethostbyaddr_r
int gethostbyaddr_r(const void *addr, socklen_t addrlen, int type,
struct hostent * result_buf,
char * buf, size_t buflen,
struct hostent ** result,
int * h_errnop)
{
struct in_addr *in;
struct in_addr **addr_list;
char **alias;
unsigned char *packet;
struct resolv_answer a;
int i;
int nest = 0;
*result = NULL;
if (!addr)
return EINVAL;
switch (type) {
#ifdef __UCLIBC_HAS_IPV4__
case AF_INET:
if (addrlen != sizeof(struct in_addr))
return EINVAL;
break;
#endif
#ifdef __UCLIBC_HAS_IPV6__
case AF_INET6:
if (addrlen != sizeof(struct in6_addr))
return EINVAL;
break;
#endif
default:
return EINVAL;
}
/* do /etc/hosts first */
i = __get_hosts_byaddr_r(addr, addrlen, type, result_buf,
buf, buflen, result, h_errnop);
if (i == 0)
return i;
switch (*h_errnop) {
case HOST_NOT_FOUND:
case NO_ADDRESS:
break;
default:
return i;
}
*h_errnop = NETDB_INTERNAL;
/* make sure pointer is aligned */
i = ALIGN_BUFFER_OFFSET(buf);
buf += i;
buflen -= i;
/* Layout in buf:
* char *alias[ALIAS_DIM];
* struct in[6]_addr* addr_list[2];
* struct in[6]_addr* in;
* char scratch_buffer[256+];
*/
#define in6 ((struct in6_addr *)in)
alias = (char **)buf;
buf += sizeof(*alias) * ALIAS_DIM;
buflen -= sizeof(*alias) * ALIAS_DIM;
addr_list = (struct in_addr**)buf;
buf += sizeof(*addr_list) * 2;
buflen -= sizeof(*addr_list) * 2;
in = (struct in_addr*)buf;
#ifndef __UCLIBC_HAS_IPV6__
buf += sizeof(*in);
buflen -= sizeof(*in);
#else
buf += sizeof(*in6);
buflen -= sizeof(*in6);
#endif
if ((ssize_t)buflen < 256)
return ERANGE;
alias[0] = buf;
alias[1] = NULL;
addr_list[0] = in;
addr_list[1] = NULL;
memcpy(&in, addr, addrlen);
if (0) /* nothing */;
#ifdef __UCLIBC_HAS_IPV4__
else IF_HAS_BOTH(if (type == AF_INET)) {
unsigned char *tp = (unsigned char *)addr;
sprintf(buf, "%u.%u.%u.%u.in-addr.arpa",
tp[3], tp[2], tp[1], tp[0]);
}
#endif
#ifdef __UCLIBC_HAS_IPV6__
else {
char *dst = buf;
unsigned char *tp = (unsigned char *)addr + addrlen - 1;
do {
dst += sprintf(dst, "%x.%x.", tp[i] & 0xf, tp[i] >> 4);
tp--;
} while (tp >= (unsigned char *)addr);
strcpy(dst, "ip6.arpa");
}
#endif
memset(&a, '\0', sizeof(a));
for (;;) {
// Hmm why we memset(a) to zeros only once?
i = __dns_lookup(buf, T_PTR, &packet, &a);
if (i < 0) {
*h_errnop = HOST_NOT_FOUND;
return TRY_AGAIN;
}
strncpy(buf, a.dotted, buflen);
free(a.dotted);
if (a.atype != T_CNAME)
break;
DPRINTF("Got a CNAME in gethostbyaddr()\n");
if (++nest > MAX_RECURSE) {
*h_errnop = NO_RECOVERY;
return -1;
}
/* Decode CNAME into buf, feed it to __dns_lookup() again */
i = __decode_dotted(packet, a.rdoffset, buf, buflen);
free(packet);
if (i < 0) {
*h_errnop = NO_RECOVERY;
return -1;
}
}
if (a.atype == T_PTR) { /* ADDRESS */
i = __decode_dotted(packet, a.rdoffset, buf, buflen);
free(packet);
result_buf->h_name = buf;
result_buf->h_addrtype = type;
result_buf->h_length = addrlen;
result_buf->h_addr_list = (char **) addr_list;
result_buf->h_aliases = alias;
*result = result_buf;
*h_errnop = NETDB_SUCCESS;
return NETDB_SUCCESS;
}
free(packet);
*h_errnop = NO_ADDRESS;
return TRY_AGAIN;
#undef in6
}
libc_hidden_def(gethostbyaddr_r)
#endif
#ifdef L_gethostent_r
__UCLIBC_MUTEX_STATIC(mylock, PTHREAD_MUTEX_INITIALIZER);
static smallint __stay_open;
static FILE * __gethostent_fp;
void endhostent(void)
{
__UCLIBC_MUTEX_LOCK(mylock);
__stay_open = 0;
if (__gethostent_fp) {
fclose(__gethostent_fp);
__gethostent_fp = NULL;
}
__UCLIBC_MUTEX_UNLOCK(mylock);
}
void sethostent(int stay_open)
{
__UCLIBC_MUTEX_LOCK(mylock);
__stay_open = (stay_open != 0);
__UCLIBC_MUTEX_UNLOCK(mylock);
}
int gethostent_r(struct hostent *result_buf, char *buf, size_t buflen,
struct hostent **result, int *h_errnop)
{
int ret;
__UCLIBC_MUTEX_LOCK(mylock);
if (__gethostent_fp == NULL) {
__gethostent_fp = __open_etc_hosts();
if (__gethostent_fp == NULL) {
*result = NULL;
ret = TRY_AGAIN;
goto DONE;
}
}
ret = __read_etc_hosts_r(__gethostent_fp, NULL, AF_INET, GETHOSTENT,
result_buf, buf, buflen, result, h_errnop);
if (__stay_open == 0) {
fclose(__gethostent_fp);
__gethostent_fp = NULL;
}
DONE:
__UCLIBC_MUTEX_UNLOCK(mylock);
return ret;
}
libc_hidden_def(gethostent_r)
#endif
#ifdef L_gethostent
struct hostent *gethostent(void)
{
static struct hostent h;
static char buf[
#ifndef __UCLIBC_HAS_IPV6__
sizeof(struct in_addr) + sizeof(struct in_addr *) * 2 +
#else
sizeof(struct in6_addr) + sizeof(struct in6_addr *) * 2 +
#endif /* __UCLIBC_HAS_IPV6__ */
sizeof(char *) * ALIAS_DIM +
80 /*namebuffer*/ + 2 /* margin */];
struct hostent *host;
gethostent_r(&h, buf, sizeof(buf), &host, &h_errno);
return host;
}
#endif
#ifdef L_gethostbyname2
struct hostent *gethostbyname2(const char *name, int family)
{
#ifndef __UCLIBC_HAS_IPV6__
return family == AF_INET ? gethostbyname(name) : (struct hostent*)NULL;
#else
static struct hostent h;
static char buf[sizeof(struct in6_addr) +
sizeof(struct in6_addr *) * 2 +
sizeof(char *)*ALIAS_DIM + 384/*namebuffer*/ + 32/* margin */];
struct hostent *hp;
gethostbyname2_r(name, family, &h, buf, sizeof(buf), &hp, &h_errno);
return hp;
#endif
}
libc_hidden_def(gethostbyname2)
#endif
#ifdef L_gethostbyname
struct hostent *gethostbyname(const char *name)
{
#ifndef __UCLIBC_HAS_IPV6__
static struct hostent h;
static char buf[sizeof(struct in_addr) +
sizeof(struct in_addr *) * 2 +
sizeof(char *)*ALIAS_DIM + 384/*namebuffer*/ + 32/* margin */];
struct hostent *hp;
gethostbyname_r(name, &h, buf, sizeof(buf), &hp, &h_errno);
return hp;
#else
return gethostbyname2(name, AF_INET);
#endif
}
libc_hidden_def(gethostbyname)
#endif
#ifdef L_gethostbyaddr
struct hostent *gethostbyaddr(const void *addr, socklen_t len, int type)
{
static struct hostent h;
static char buf[
#ifndef __UCLIBC_HAS_IPV6__
sizeof(struct in_addr) + sizeof(struct in_addr *)*2 +
#else
sizeof(struct in6_addr) + sizeof(struct in6_addr *)*2 +
#endif /* __UCLIBC_HAS_IPV6__ */
sizeof(char *)*ALIAS_DIM + 384 /*namebuffer*/ + 32 /* margin */];
struct hostent *hp;
gethostbyaddr_r(addr, len, type, &h, buf, sizeof(buf), &hp, &h_errno);
return hp;
}
libc_hidden_def(gethostbyaddr)
#endif
#ifdef L_res_comp
/*
* Expand compressed domain name 'comp_dn' to full domain name.
* 'msg' is a pointer to the begining of the message,
* 'eomorig' points to the first location after the message,
* 'exp_dn' is a pointer to a buffer of size 'length' for the result.
* Return size of compressed name or -1 if there was an error.
*/
int __dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
char *dst, int dstsiz)
{
int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
if (n > 0 && dst[0] == '.')
dst[0] = '\0';
return n;
}
#endif /* L_res_comp */
#ifdef L_ns_name
/* Thinking in noninternationalized USASCII (per the DNS spec),
* is this character visible and not a space when printed ?
*/
static int printable(int ch)
{
return (ch > 0x20 && ch < 0x7f);
}
/* Thinking in noninternationalized USASCII (per the DNS spec),
* is this characted special ("in need of quoting") ?
*/
static int special(int ch)
{
switch (ch) {
case 0x22: /* '"' */
case 0x2E: /* '.' */
case 0x3B: /* ';' */
case 0x5C: /* '\\' */
/* Special modifiers in zone files. */
case 0x40: /* '@' */
case 0x24: /* '$' */
return 1;
default:
return 0;
}
}
/*
* ns_name_uncompress(msg, eom, src, dst, dstsiz)
* Expand compressed domain name to presentation format.
* return:
* Number of bytes read out of `src', or -1 (with errno set).
* note:
* Root domain returns as "." not "".
*/
int ns_name_uncompress(const u_char *msg, const u_char *eom,
const u_char *src, char *dst, size_t dstsiz)
{
u_char tmp[NS_MAXCDNAME];
int n;
n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp);
if (n == -1)
return -1;
if (ns_name_ntop(tmp, dst, dstsiz) == -1)
return -1;
return n;
}
libc_hidden_def(ns_name_uncompress)
/*
* ns_name_ntop(src, dst, dstsiz)
* Convert an encoded domain name to printable ascii as per RFC1035.
* return:
* Number of bytes written to buffer, or -1 (with errno set)
* notes:
* The root is returned as "."
* All other domains are returned in non absolute form
*/
int ns_name_ntop(const u_char *src, char *dst, size_t dstsiz)
{
static const char digits[] = "0123456789";
const u_char *cp;
char *dn, *eom;
u_char c;
u_int n;
cp = src;
dn = dst;
eom = dst + dstsiz;
while ((n = *cp++) != 0) {
if ((n & NS_CMPRSFLGS) != 0) {
/* Some kind of compression pointer. */
__set_errno(EMSGSIZE);
return -1;
}
if (dn != dst) {
if (dn >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = '.';
}
if (dn + n >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
for (; n > 0; n--) {
c = *cp++;
if (special(c)) {
if (dn + 1 >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = '\\';
*dn++ = (char)c;
} else if (!printable(c)) {
if (dn + 3 >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = '\\';
*dn++ = digits[c / 100];
*dn++ = digits[(c % 100) / 10];
*dn++ = digits[c % 10];
} else {
if (dn >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = (char)c;
}
}
}
if (dn == dst) {
if (dn >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = '.';
}
if (dn >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
*dn++ = '\0';
return (dn - dst);
}
libc_hidden_def(ns_name_ntop)
/*
* ns_name_unpack(msg, eom, src, dst, dstsiz)
* Unpack a domain name from a message, source may be compressed.
* return:
* -1 if it fails, or consumed octets if it succeeds.
*/
int ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
u_char *dst, size_t dstsiz)
{
const u_char *srcp, *dstlim;
u_char *dstp;
int n, len, checked;
len = -1;
checked = 0;
dstp = dst;
srcp = src;
dstlim = dst + dstsiz;
if (srcp < msg || srcp >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
/* Fetch next label in domain name. */
while ((n = *srcp++) != 0) {
/* Check for indirection. */
switch (n & NS_CMPRSFLGS) {
case 0:
/* Limit checks. */
if (dstp + n + 1 >= dstlim || srcp + n >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
checked += n + 1;
*dstp++ = n;
memcpy(dstp, srcp, n);
dstp += n;
srcp += n;
break;
case NS_CMPRSFLGS:
if (srcp >= eom) {
__set_errno(EMSGSIZE);
return -1;
}
if (len < 0)
len = srcp - src + 1;
srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
if (srcp < msg || srcp >= eom) { /* Out of range. */
__set_errno(EMSGSIZE);
return -1;
}
checked += 2;
/*
* Check for loops in the compressed name;
* if we've looked at the whole message,
* there must be a loop.
*/
if (checked >= eom - msg) {
__set_errno(EMSGSIZE);
return -1;
}
break;
default:
__set_errno(EMSGSIZE);
return -1; /* flag error */
}
}
*dstp = '\0';
if (len < 0)
len = srcp - src;
return len;
}
libc_hidden_def(ns_name_unpack)
#endif /* L_ns_name */
#ifdef L_res_init
/* Protected by __resolv_lock */
struct __res_state _res;
/* Will be called under __resolv_lock. */
static void res_sync_func(void)
{
struct __res_state *rp = &(_res);
int n;
/* If we didn't get malloc failure earlier... */
if (__nameserver != (void*) &__local_nameserver) {
/* TODO:
* if (__nameservers < rp->nscount) - try to grow __nameserver[]?
*/
#ifdef __UCLIBC_HAS_IPV6__
if (__nameservers > rp->_u._ext.nscount)
__nameservers = rp->_u._ext.nscount;
n = __nameservers;
while (--n >= 0)
__nameserver[n].sa6 = *rp->_u._ext.nsaddrs[n]; /* struct copy */
#else /* IPv4 only */
if (__nameservers > rp->nscount)
__nameservers = rp->nscount;
n = __nameservers;
while (--n >= 0)
__nameserver[n].sa4 = rp->nsaddr_list[n]; /* struct copy */
#endif
}
/* Extend and comment what program is known
* to use which _res.XXX member(s).
*/
// __resolv_opts = rp->options;
// ...
}
/* Our res_init never fails (always returns 0) */
int res_init(void)
{
struct __res_state *rp = &(_res);
int i;
int n;
#ifdef __UCLIBC_HAS_IPV6__
int m = 0;
#endif
__UCLIBC_MUTEX_LOCK(__resolv_lock);
__close_nameservers();
__open_nameservers();
__res_sync = res_sync_func;
memset(rp, 0, sizeof(*rp));
rp->options = RES_INIT;
#ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
rp->retrans = RES_TIMEOUT;
rp->retry = 4;
//TODO: pulls in largish static buffers... use simpler one?
rp->id = random();
#endif
rp->ndots = 1;
#ifdef __UCLIBC_HAS_EXTRA_COMPAT_RES_STATE__
rp->_vcsock = -1;
#endif
n = __searchdomains;
if (n > ARRAY_SIZE(rp->dnsrch))
n = ARRAY_SIZE(rp->dnsrch);
for (i = 0; i < n; i++)
rp->dnsrch[i] = __searchdomain[i];
/* copy nameservers' addresses */
i = 0;
#ifdef __UCLIBC_HAS_IPV4__
n = 0;
while (n < ARRAY_SIZE(rp->nsaddr_list) && i < __nameservers) {
if (__nameserver[i].sa.sa_family == AF_INET) {
rp->nsaddr_list[n] = __nameserver[i].sa4; /* struct copy */
#ifdef __UCLIBC_HAS_IPV6__
if (m < ARRAY_SIZE(rp->_u._ext.nsaddrs)) {
rp->_u._ext.nsaddrs[m] = (void*) &rp->nsaddr_list[n];
m++;
}
#endif
n++;
}
#ifdef __UCLIBC_HAS_IPV6__
if (__nameserver[i].sa.sa_family == AF_INET6
&& m < ARRAY_SIZE(rp->_u._ext.nsaddrs)
) {
struct sockaddr_in6 *sa6 = malloc(sizeof(sa6));
if (sa6) {
*sa6 = __nameserver[i].sa6; /* struct copy */
rp->_u._ext.nsaddrs[m] = sa6;
m++;
}
}
#endif
i++;
}
rp->nscount = n;
#ifdef __UCLIBC_HAS_IPV6__
rp->_u._ext.nscount = m;
#endif
#else /* IPv6 only */
while (m < ARRAY_SIZE(rp->_u._ext.nsaddrs) && i < __nameservers) {
struct sockaddr_in6 *sa6 = malloc(sizeof(sa6));
if (sa6) {
*sa6 = __nameserver[i].sa6; /* struct copy */
rp->_u._ext.nsaddrs[m] = sa6;
m++;
}
i++;
}
rp->_u._ext.nscount = m;
#endif
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
return 0;
}
libc_hidden_def(res_init)
#ifdef __UCLIBC_HAS_BSD_RES_CLOSE__
void res_close(void)
{
__UCLIBC_MUTEX_LOCK(__resolv_lock);
__close_nameservers();
__res_sync = NULL;
#ifdef __UCLIBC_HAS_IPV6__
{
char *p1 = (char*) &(_res.nsaddr_list[0]);
int m = 0;
/* free nsaddrs[m] if they do not point to nsaddr_list[x] */
while (m < ARRAY_SIZE(_res._u._ext.nsaddrs)) {
char *p2 = (char*)(_res._u._ext.nsaddrs[m]);
if (p2 < p1 || (p2 - p1) > sizeof(_res.nsaddr_list))
free(p2);
}
}
#endif
memset(&_res, 0, sizeof(_res));
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
}
#endif
#endif /* L_res_init */
#ifdef L_res_query
int res_query(const char *dname, int class, int type,
unsigned char *answer, int anslen)
{
int i;
unsigned char * packet = NULL;
struct resolv_answer a;
if (!dname || class != 1 /* CLASS_IN */) {
h_errno = NO_RECOVERY;
return -1;
}
memset(&a, '\0', sizeof(a));
i = __dns_lookup(dname, type, &packet, &a);
if (i < 0) {
h_errno = TRY_AGAIN;
return -1;
}
free(a.dotted);
if (a.atype == type) { /* CNAME */
if (i > anslen)
i = anslen;
memcpy(answer, packet, i);
}
free(packet);
return i;
}
libc_hidden_def(res_query)
/*
* 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.
*/
#define __TRAILING_DOT (1<<0)
#define __GOT_NODATA (1<<1)
#define __GOT_SERVFAIL (1<<2)
#define __TRIED_AS_IS (1<<3)
int res_search(const char *name, int class, int type, u_char *answer,
int anslen)
{
const char *cp, * const *domain;
HEADER *hp = (HEADER *)(void *)answer;
unsigned dots;
unsigned state;
int ret, saved_herrno;
uint32_t _res_options;
unsigned _res_ndots;
char **_res_dnsrch;
if (!name || !answer) {
h_errno = NETDB_INTERNAL;
return -1;
}
again:
__UCLIBC_MUTEX_LOCK(__resolv_lock);
_res_options = _res.options;
_res_ndots = _res.ndots;
_res_dnsrch = _res.dnsrch;
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
if (!(_res_options & RES_INIT)) {
res_init(); /* our res_init never fails */
goto again;
}
state = 0;
errno = 0;
h_errno = HOST_NOT_FOUND; /* default, if we never query */
dots = 0;
for (cp = name; *cp; cp++)
dots += (*cp == '.');
if (cp > name && *--cp == '.')
state |= __TRAILING_DOT;
/*
* 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_querydomain(name, NULL, class, type, answer, anslen);
if (ret > 0)
return ret;
saved_herrno = h_errno;
state |= __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 && !(state & __TRAILING_DOT) && (_res_options & RES_DNSRCH))
) {
bool done = 0;
for (domain = (const char * const *)_res_dnsrch;
*domain && !done;
domain++) {
ret = res_querydomain(name, *domain, class, type,
answer, anslen);
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:
state |= __GOT_NODATA;
/* FALLTHROUGH */
case HOST_NOT_FOUND:
/* keep trying */
break;
case TRY_AGAIN:
if (hp->rcode == SERVFAIL) {
/* try next search element, if any */
state |= __GOT_SERVFAIL;
break;
}
/* FALLTHROUGH */
default:
/* anything else implies that we're done */
done = 1;
}
/*
* 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 = 1;
}
}
/*
* 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 (!(state & __TRIED_AS_IS)) {
ret = res_querydomain(name, NULL, class, type, answer, anslen);
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 (state & __GOT_NODATA)
h_errno = NO_DATA;
else if (state & __GOT_SERVFAIL)
h_errno = TRY_AGAIN;
return -1;
}
#undef __TRAILING_DOT
#undef __GOT_NODATA
#undef __GOT_SERVFAIL
#undef __TRIED_AS_IS
/*
* Perform a call on res_query on the concatenation of name and domain,
* removing a trailing dot from name if domain is NULL.
*/
int res_querydomain(const char *name, const char *domain, int class, int type,
u_char * answer, int anslen)
{
char nbuf[MAXDNAME];
const char *longname = nbuf;
size_t n, d;
#ifdef DEBUG
uint32_t _res_options;
#endif
if (!name || !answer) {
h_errno = NETDB_INTERNAL;
return -1;
}
#ifdef DEBUG
again:
__UCLIBC_MUTEX_LOCK(__resolv_lock);
_res_options = _res.options;
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
if (!(_res_options & RES_INIT)) {
res_init(); /* our res_init never fails */
goto again:
}
if (_res_options & RES_DEBUG)
printf(";; res_querydomain(%s, %s, %d, %d)\n",
name, (domain ? domain : "<Nil>"), class, type);
#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_query(longname, class, type, answer, anslen);
}
libc_hidden_def(res_querydomain)
/* res_mkquery */
/* res_send */
/* dn_comp */
/* dn_expand */
#endif
/* vi: set sw=4 ts=4: */
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