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|
- /* vi: set sw=4 ts=4: */
- /* 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()
- *
- * 2008, 2009 Denys Vlasenko <vda.linux@googlemail.com>
- * Cleanups, fixes, readability, more cleanups and more fixes.
- *
- * March 2010 Bernhard Reutner-Fischer
- * Switch to common config parser
- */
- /* Nota bene:
- * The whole resolver code has several (severe) problems:
- * - it doesn't even build without IPv4, i.e. !UCLIBC_HAS_IPV4 but only IPv6
- * - it is way too big
- *
- * Both points above are considered bugs, patches/reimplementations welcome.
- */
- /* RFC 1035
- ...
- Whenever an octet represents a numeric quantity, the left most bit
- in the diagram is the high order or most significant bit.
- That is, the bit labeled 0 is the most significant bit.
- ...
- 4.1.1. Header section format
- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | ID |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- |QR| OPCODE |AA|TC|RD|RA| 0 0 0| RCODE |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | QDCOUNT |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | ANCOUNT |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | NSCOUNT |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | ARCOUNT |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- ID 16 bit random identifier assigned by querying peer.
- Used to match query/response.
- QR message is a query (0), or a response (1).
- OPCODE 0 standard query (QUERY)
- 1 inverse query (IQUERY)
- 2 server status request (STATUS)
- AA Authoritative Answer - this bit is valid in responses.
- Responding name server is an authority for the domain name
- in question section. Answer section may have multiple owner names
- because of aliases. The AA bit corresponds to the name which matches
- the query name, or the first owner name in the answer section.
- TC TrunCation - this message was truncated.
- RD Recursion Desired - this bit may be set in a query and
- is copied into the response. If RD is set, it directs
- the name server to pursue the query recursively.
- Recursive query support is optional.
- RA Recursion Available - this be is set or cleared in a
- response, and denotes whether recursive query support is
- available in the name server.
- RCODE Response code.
- 0 No error condition
- 1 Format error
- 2 Server failure - server was unable to process the query
- due to a problem with the name server.
- 3 Name Error - meaningful only for responses from
- an authoritative name server. The referenced domain name
- does not exist.
- 4 Not Implemented.
- 5 Refused.
- QDCOUNT number of entries in the question section.
- ANCOUNT number of records in the answer section.
- NSCOUNT number of records in the authority records section.
- ARCOUNT number of records in the additional records section.
- 4.1.2. Question section format
- The section contains QDCOUNT (usually 1) entries, each of this format:
- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- / QNAME /
- / /
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | QTYPE |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | QCLASS |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- QNAME a domain name represented as a sequence of labels, where
- each label consists of a length octet followed by that
- number of octets. The domain name terminates with the
- zero length octet for the null label of the root. Note
- that this field may be an odd number of octets; no
- padding is used.
- QTYPE a two octet type of the query.
- 1 a host address [REQ_A const]
- 2 an authoritative name server
- 3 a mail destination (Obsolete - use MX)
- 4 a mail forwarder (Obsolete - use MX)
- 5 the canonical name for an alias
- 6 marks the start of a zone of authority
- 7 a mailbox domain name (EXPERIMENTAL)
- 8 a mail group member (EXPERIMENTAL)
- 9 a mail rename domain name (EXPERIMENTAL)
- 10 a null RR (EXPERIMENTAL)
- 11 a well known service description
- 12 a domain name pointer [REQ_PTR const]
- 13 host information
- 14 mailbox or mail list information
- 15 mail exchange
- 16 text strings
- 0x1c IPv6?
- 252 a request for a transfer of an entire zone
- 253 a request for mailbox-related records (MB, MG or MR)
- 254 a request for mail agent RRs (Obsolete - see MX)
- 255 a request for all records
- QCLASS a two octet code that specifies the class of the query.
- 1 the Internet
- (others are historic only)
- 255 any class
- 4.1.3. Resource record format
- The answer, authority, and additional sections all share the same format:
- a variable number of resource records, where the number of records
- is specified in the corresponding count field in the header.
- Each resource record has this format:
- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- / /
- / NAME /
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | TYPE |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | CLASS |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | TTL |
- | |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | RDLENGTH |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
- / RDATA /
- / /
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- NAME a domain name to which this resource record pertains.
- TYPE two octets containing one of the RR type codes. This
- field specifies the meaning of the data in the RDATA field.
- CLASS two octets which specify the class of the data in the RDATA field.
- TTL a 32 bit unsigned integer that specifies the time interval
- (in seconds) that the record may be cached.
- RDLENGTH a 16 bit integer, length in octets of the RDATA field.
- RDATA a variable length string of octets that describes the resource.
- The format of this information varies according to the TYPE
- and CLASS of the resource record.
- If the TYPE is A and the CLASS is IN, it's a 4 octet IP address.
- 4.1.4. Message compression
- In order to reduce the size of messages, domain names can be compressed.
- An entire domain name or a list of labels at the end of a domain name
- is replaced with a pointer to a prior occurance of the same name.
- The pointer takes the form of a two octet sequence:
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- | 1 1| OFFSET |
- +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
- The first two bits are ones. This allows a pointer to be distinguished
- from a label, since the label must begin with two zero bits because
- labels are restricted to 63 octets or less. The OFFSET field specifies
- an offset from the start of the message (i.e., the first octet
- of the ID field in the domain header).
- A zero offset specifies the first byte of the ID field, etc.
- Domain name in a message can be represented as either:
- - a sequence of labels ending in a zero octet
- - a pointer
- - a sequence of labels ending with a pointer
- */
- #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 <sys/stat.h>
- #include <bits/uClibc_mutex.h>
- #include "internal/parse_config.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
- #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 MAXALIASES (4)
- #define BUFSZ (80) /* one line */
- #define SBUFSIZE (BUFSZ + 1 + (sizeof(char *) * MAXALIASES))
- #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 uint8_t __resolv_timeout attribute_hidden;
- extern uint8_t __resolv_attempts 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
- /* prototypes for internal functions */
- extern void endhostent_unlocked(void) attribute_hidden;
- 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 parser_t *__open_etc_hosts(void) attribute_hidden;
- extern int __read_etc_hosts_r(parser_t *parser,
- 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 *packet,
- int offset,
- int packet_len,
- char *dest,
- int dest_len) 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 *q,
- unsigned char *dest,
- int maxlen) attribute_hidden;
- extern int __encode_answer(struct resolv_answer *a,
- unsigned char *dest,
- int maxlen) attribute_hidden;
- extern void __open_nameservers(void) attribute_hidden;
- extern void __close_nameservers(void) attribute_hidden;
- /*
- * 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 timeout:n and attempts:n)
- * $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.
- * It is reread if its mtime is changed.
- *
- * 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 *packet,
- int offset,
- int packet_len,
- char *dest,
- int dest_len)
- {
- unsigned b;
- bool measure = 1;
- unsigned total = 0;
- unsigned used = 0;
- if (!packet)
- return -1;
- while (1) {
- if (offset >= packet_len)
- return -1;
- b = packet[offset++];
- if (b == 0)
- break;
- if (measure)
- total++;
- if ((b & 0xc0) == 0xc0) {
- if (offset >= packet_len)
- return -1;
- if (measure)
- total++;
- /* compressed item, redirect */
- offset = ((b & 0x3f) << 8) | packet[offset];
- measure = 0;
- continue;
- }
- if (used + b + 1 >= dest_len)
- return -1;
- if (offset + b >= packet_len)
- return -1;
- memcpy(dest + used, packet + offset, b);
- offset += b;
- used += b;
- if (measure)
- total += b;
- if (packet[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_encodeq
- int attribute_hidden __encode_question(const struct resolv_question *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_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 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; */
- uint8_t __resolv_timeout = RES_TIMEOUT;
- uint8_t __resolv_attempts = RES_DFLRETRY;
- 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 uint32_t resolv_conf_mtime;
- char szBuffer[MAXLEN_searchdomain];
- FILE *fp;
- int i;
- sockaddr46_t sa;
- if (!__res_sync) {
- /* Reread /etc/resolv.conf if it was modified. */
- struct stat sb;
- if (stat("/etc/resolv.conf", &sb) != 0)
- sb.st_mtime = 0;
- if (resolv_conf_mtime != (uint32_t)sb.st_mtime) {
- resolv_conf_mtime = sb.st_mtime;
- __close_nameservers(); /* force config reread */
- }
- }
- if (__nameservers)
- goto sync;
- __resolv_timeout = RES_TIMEOUT;
- __resolv_attempts = RES_DFLRETRY;
- fp = fopen("/etc/resolv.conf", "r");
- #ifdef FALLBACK_TO_CONFIG_RESOLVCONF
- if (!fp) {
- /* If we do not have a pre-populated /etc/resolv.conf then
- try to use the one from /etc/config which exists on numerous
- systems ranging from some uClinux to IRIX installations and
- may be the only /etc dir that was mounted rw. */
- fp = fopen("/etc/config/resolv.conf", "r");
- }
- #endif
- 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) {
- char *p1;
- uint8_t *what;
- if (p == NULL || (p1 = strchr(p, ':')) == NULL)
- continue;
- *p1++ = '\0';
- if (strcmp(p, "timeout") == 0)
- what = &__resolv_timeout;
- else if (strcmp(p, "attempts") == 0)
- what = &__resolv_attempts;
- else
- continue;
- *what = atoi(p1);
- DPRINTF("option %s:%d\n", p, *what);
- }
- }
- 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
- /* Helpers */
- static int __length_question(const unsigned char *data, int maxlen)
- {
- const unsigned char *start;
- unsigned b;
- if (!data)
- return -1;
- start = data;
- while (1) {
- if (maxlen <= 0)
- return -1;
- b = *data++;
- if (b == 0)
- break;
- if ((b & 0xc0) == 0xc0) {
- /* It's a "compressed" name. */
- data++; /* skip lsb of redirected offset */
- maxlen -= 2;
- break;
- }
- data += b;
- maxlen -= (b + 1); /* account for data++ above */
- }
- /* Up to here we were skipping encoded name */
- /* Account for QTYPE and QCLASS fields */
- if (maxlen < 4)
- return -1;
- return data - start + 2 + 2;
- }
- static int __decode_answer(const unsigned char *message, /* packet */
- int offset,
- int len, /* total packet 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, len, 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;
- }
- /* 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
- * ret >= 0: length of reply packet
- * 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, fd, rc;
- int packet_len;
- 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 {
- int pos;
- 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;
- retries_left = __nameservers * __resolv_attempts;
- }
- 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;
- packet_len = i + j;
- /* send packet */
- #ifdef DEBUG
- {
- const socklen_t plen = sa.sa.sa_family == AF_INET ? INET_ADDRSTRLEN : INET6_ADDRSTRLEN;
- char *pbuf = malloc(plen);
- if (pbuf == NULL) ;/* nothing */
- #ifdef __UCLIBC_HAS_IPV6__
- else if (sa.sa.sa_family == AF_INET6)
- pbuf = (char*)inet_ntop(AF_INET6, &sa.sa6.sin6_addr, pbuf, plen);
- #endif
- #ifdef __UCLIBC_HAS_IPV4__
- else if (sa.sa.sa_family == AF_INET)
- pbuf = (char*)inet_ntop(AF_INET, &sa.sa4.sin_addr, pbuf, plen);
- #endif
- DPRINTF("On try %d, sending query to %s, port %d\n",
- retries_left, pbuf, NAMESERVER_PORT);
- free(pbuf);
- }
- #endif
- 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", packet_len, h.id, h.qr);
- /* no error check - if it fails, we time out on recv */
- send(fd, packet, packet_len, 0);
- #ifdef USE_SELECT
- reply_timeout = __resolv_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 = __resolv_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
- /* vda: a bogus response seen in real world (caused SEGV in uclibc):
- * "ping www.google.com" sending AAAA query and getting
- * response with one answer... with answer part missing!
- * Fixed by thorough checks for not going past the packet's end.
- */
- #ifdef DEBUG
- {
- static const char test_query[32] = "\0\2\1\0\0\1\0\0\0\0\0\0\3www\6google\3com\0\0\34\0\1";
- static const char test_respn[32] = "\0\2\201\200\0\1\0\1\0\0\0\0\3www\6google\3com\0\0\34\0\1";
- pos = memcmp(packet + 2, test_query + 2, 30);
- packet_len = recv(fd, packet, PACKETSZ, MSG_DONTWAIT);
- if (pos == 0) {
- packet_len = 32;
- memcpy(packet + 2, test_respn + 2, 30);
- }
- }
- #else
- packet_len = recv(fd, packet, PACKETSZ, MSG_DONTWAIT);
- #endif
- if (packet_len < HFIXEDSZ) {
- /* too short!
- * If the peer did shutdown then retry later,
- * try next peer on error.
- * it's just a bogus packet from somewhere */
- bogus_packet:
- if (packet_len >= 0 && reply_timeout)
- goto wait_again;
- goto try_next_server;
- }
- __decode_header(packet, &h);
- DPRINTF("len:%d id:%d qr:%d\n", packet_len, 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 to check for?] */
- goto fail1;
- }
- pos = HFIXEDSZ;
- for (j = 0; j < h.qdcount; j++) {
- DPRINTF("Skipping question %d at %d\n", j, pos);
- i = __length_question(packet + pos, packet_len - pos);
- if (i < 0) {
- DPRINTF("Packet'question section "
- "is truncated, trying next server\n");
- goto try_next_server;
- }
- pos += i;
- DPRINTF("Length of question %d is %d\n", j, i);
- }
- DPRINTF("Decoding answer at pos %d\n", pos);
- first_answer = 1;
- for (j = 0; j < h.ancount; j++) {
- i = __decode_answer(packet, pos, packet_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)
- 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 packet_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
- parser_t * __open_etc_hosts(void)
- {
- parser_t * parser;
- if ((parser = config_open("/etc/hosts")) == NULL) {
- #ifdef FALLBACK_TO_CONFIG_RESOLVCONF
- parser = config_open("/etc/config/hosts");
- #endif
- }
- return parser;
- }
- #define MINTOKENS 2 //dotted ip address + canonical name
- #define MAXTOKENS (MINTOKENS + MAXALIASES)
- #define HALISTOFF (sizeof(char*) * MAXTOKENS)
- #define INADDROFF (HALISTOFF + 2 * sizeof(char*))
- int attribute_hidden __read_etc_hosts_r(
- parser_t * parser,
- 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)
- {
- char **alias;
- char **host_aliases;
- char **tok = NULL;
- struct in_addr *h_addr0 = NULL;
- const size_t aliaslen = INADDROFF +
- #ifdef __UCLIBC_HAS_IPV6__
- sizeof(struct in6_addr)
- #else
- sizeof(struct in_addr)
- #endif
- ;
- int ret = HOST_NOT_FOUND;
- *h_errnop = NETDB_INTERNAL;
- if (buflen < aliaslen
- || (buflen - aliaslen) < BUFSZ + 1)
- return ERANGE;
- if (parser == NULL)
- parser = __open_etc_hosts();
- if (parser == NULL) {
- *result = NULL;
- return errno;
- }
- /* Layout in buf:
- * char *alias[MAXTOKENS] = {address, name, aliases...}
- * char **h_addr_list[1] = {*in[6]_addr, NULL}
- * struct in[6]_addr
- * char line_buffer[BUFSZ+];
- */
- parser->data = buf;
- parser->data_len = aliaslen;
- parser->line_len = buflen - aliaslen;
- *h_errnop = HOST_NOT_FOUND;
- /* <ip>[[:space:]][<aliases>] */
- while (config_read(parser, &tok, MAXTOKENS, MINTOKENS, "# \t", PARSE_NORMAL)) {
- result_buf->h_aliases = alias = host_aliases = tok+1;
- if (action == GETHOSTENT) {
- /* Return whatever the next entry happens to be. */
- break;
- }
- if (action == GET_HOSTS_BYADDR) {
- if (strcmp(name, *tok) != 0)
- continue;
- } else { /* GET_HOSTS_BYNAME */
- while (*alias) {
- if (strcasecmp(name, *(alias++)) == 0)
- goto found;
- }
- continue;
- }
- found:
- result_buf->h_name = *(result_buf->h_aliases++);
- result_buf->h_addr_list = (char**)(buf + HALISTOFF);
- *(result_buf->h_addr_list + 1) = '\0';
- h_addr0 = (struct in_addr*)(buf + INADDROFF);
- result_buf->h_addr = (char*)h_addr0;
- if (0) /* nothing */;
- #ifdef __UCLIBC_HAS_IPV4__
- else if (type == AF_INET
- && inet_pton(AF_INET, *tok, h_addr0) > 0) {
- DPRINTF("Found INET\n");
- result_buf->h_addrtype = AF_INET;
- result_buf->h_length = sizeof(struct in_addr);
- *result = result_buf;
- ret = NETDB_SUCCESS;
- }
- #endif
- #ifdef __UCLIBC_HAS_IPV6__
- #define in6 ((struct in6_addr *)buf)
- else if (type == AF_INET6
- && inet_pton(AF_INET6, *tok, h_addr0) > 0) {
- DPRINTF("Found INET6\n");
- result_buf->h_addrtype = AF_INET6;
- result_buf->h_length = sizeof(struct in6_addr);
- *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 different address family\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)
- config_close(parser);
- 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 flags)
- {
- int serrno = errno;
- unsigned ok;
- struct hostent *hoste = 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)
- hoste = gethostbyaddr((const void *)
- &(((const struct sockaddr_in6 *) sa)->sin6_addr),
- sizeof(struct in6_addr), AF_INET6);
- #endif
- #ifdef __UCLIBC_HAS_IPV4__
- else
- hoste = gethostbyaddr((const void *)
- &(((const struct sockaddr_in *)sa)->sin_addr),
- sizeof(struct in_addr), AF_INET);
- #endif
- if (hoste) {
- char *c;
- #undef min
- #define min(x,y) (((x) > (y)) ? (y) : (x))
- if ((flags & NI_NOFQDN)
- && (getdomainname(domain, sizeof(domain)) == 0)
- && (c = strstr(hoste->h_name, domain)) != NULL
- && (c != hoste->h_name) && (*(--c) == '.')
- ) {
- strncpy(host, hoste->h_name,
- min(hostlen, (size_t) (c - hoste->h_name)));
- host[min(hostlen - 1, (size_t) (c - hoste->h_name))] = '\0';
- } else {
- strncpy(host, hoste->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
- /* 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 packet_len;
- 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;
- packet_len = __dns_lookup(name, T_A, &packet, &a);
- if (packet_len < 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)
- link_warning(gethostbyname_r, "gethostbyname_r is obsolescent, use getnameinfo() instead.");
- #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 (;;) {
- int packet_len;
- /* Hmm why we memset(a) to zeros only once? */
- packet_len = __dns_lookup(buf, T_AAAA, &packet, &a);
- if (packet_len < 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, packet_len, 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 packet_len;
- 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;
- 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);
- if (addrlen > sizeof(*in))
- return ERANGE;
- #else
- buf += sizeof(*in6);
- buflen -= sizeof(*in6);
- if (addrlen > sizeof(*in6))
- return ERANGE;
- #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[0] & 0xf, tp[0] >> 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? */
- packet_len = __dns_lookup(buf, T_PTR, &packet, &a);
- if (packet_len < 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, packet_len, 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, packet_len, 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)
- link_warning(gethostbyaddr_r, "gethostbyaddr_r is obsolescent, use getaddrinfo() instead.");
- #endif
- #ifdef L_gethostent_r
- __UCLIBC_MUTEX_STATIC(mylock, PTHREAD_MUTEX_INITIALIZER);
- static parser_t *hostp = NULL;
- static smallint host_stayopen;
- void endhostent_unlocked(void)
- {
- if (hostp) {
- config_close(hostp);
- hostp = NULL;
- }
- host_stayopen = 0;
- }
- void endhostent(void)
- {
- __UCLIBC_MUTEX_LOCK(mylock);
- endhostent_unlocked();
- __UCLIBC_MUTEX_UNLOCK(mylock);
- }
- void sethostent(int stay_open)
- {
- __UCLIBC_MUTEX_LOCK(mylock);
- if (stay_open)
- host_stayopen = 1;
- __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 (hostp == NULL) {
- hostp = __open_etc_hosts();
- if (hostp == NULL) {
- *result = NULL;
- ret = TRY_AGAIN;
- goto DONE;
- }
- }
- ret = __read_etc_hosts_r(hostp, NULL, AF_INET, GETHOSTENT,
- result_buf, buf, buflen, result, h_errnop);
- if (!host_stayopen)
- endhostent_unlocked();
- DONE:
- __UCLIBC_MUTEX_UNLOCK(mylock);
- return ret;
- }
- libc_hidden_def(gethostent_r)
- #endif
- #ifdef L_gethostent
- struct hostent *gethostent(void)
- {
- static struct hostent hoste;
- 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__ */
- BUFSZ /*namebuffer*/ + 2 /* margin */];
- struct hostent *host;
- gethostent_r(&hoste, 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 hoste;
- 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, &hoste, 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 hoste;
- 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, &hoste, buf, sizeof(buf), &hp, &h_errno);
- return hp;
- #else
- return gethostbyname2(name, AF_INET);
- #endif
- }
- libc_hidden_def(gethostbyname)
- link_warning(gethostbyname, "gethostbyname is obsolescent, use getnameinfo() instead.");
- #endif
- #ifdef L_gethostbyaddr
- struct hostent *gethostbyaddr(const void *addr, socklen_t len, int type)
- {
- static struct hostent hoste;
- 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, &hoste, buf, sizeof(buf), &hp, &h_errno);
- return hp;
- }
- libc_hidden_def(gethostbyaddr)
- link_warning(gethostbyaddr, "gethostbyaddr is obsolescent, use getaddrinfo() instead.");
- #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
- /* 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
- }
- __resolv_timeout = rp->retrans ? : RES_TIMEOUT;
- __resolv_attempts = rp->retry ? : RES_DFLRETRY;
- /* 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;
- rp->retrans = RES_TIMEOUT;
- rp->retry = RES_DFLRETRY;
- rp->ndots = 1;
- #ifdef __UCLIBC_HAS_COMPAT_RES_STATE__
- /* Was: "rp->id = random();" but:
- * - random() pulls in largish static buffers
- * - isn't actually random unless, say, srandom(time(NULL)) was called
- * - is not used by uclibc anyway :)
- */
- /* rp->id = 0; - memset did it */
- #endif
- #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
- /* This needs to be after the use of _res in res_init, above. */
- #undef _res
- #ifndef __UCLIBC_HAS_THREADS__
- /* The resolver state for use by single-threaded programs.
- This differs from plain `struct __res_state _res;' in that it doesn't
- create a common definition, but a plain symbol that resides in .bss,
- which can have an alias. */
- struct __res_state _res __attribute__((section (".bss")));
- struct __res_state *__resp = &_res;
- #else /* __UCLIBC_HAS_THREADS__ */
- struct __res_state _res __attribute__((section (".bss"))) attribute_hidden;
- # if defined __UCLIBC_HAS_TLS__
- # undef __resp
- __thread struct __res_state *__resp = &_res;
- /*
- * FIXME: Add usage of hidden attribute for this when used in the shared
- * library. It currently crashes the linker when doing section
- * relocations.
- */
- extern __thread struct __res_state *__libc_resp
- __attribute__ ((alias ("__resp"))) attribute_hidden;
- # else
- # undef __resp
- struct __res_state *__resp = &_res;
- # endif
- #endif
- #endif /* L_res_init */
- #ifdef L_res_state
- # if defined __UCLIBC_HAS_TLS__
- struct __res_state *
- __res_state (void)
- {
- return __resp;
- }
- # else
- # undef _res
- extern struct __res_state _res;
- /* When threaded, _res may be a per-thread variable. */
- struct __res_state *
- weak_const_function
- __res_state (void)
- {
- return &_res;
- }
- # endif
- #endif
- #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) {
- if (!h_errno) /* TODO: can this ever happen? */
- 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;
- char **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 = _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)
- #endif
- /* Unimplemented: */
- /* res_mkquery */
- /* res_send */
- /* dn_comp */
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