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freebsd-nq/include/resolv.h
Brian Feldman 33dee81933 Make the resolver(3) and many associated interfaces much more reentrant. 
The getaddrinfo(3), getipnodebyname(3) and resolver(3) can coincide now
with what should be totally reentrant, and h_errno values will now
be preserved correctly, but this does not affect interfaces such as
gethostbyname(3) which are still mostly non-reentrant.

In all of these relevant functions, the thread-safety has been pushed
down as far as it seems possible right now.  This means that operations
that are selected via nsdispatch(3) (i.e. files, yp, dns) are protected
still under global locks that getaddrinfo(3) defines, but where possible
the locking is greatly reduced.  The most noticeable improvement is
that multiple DNS lookups can now be run at the same time, and this
shows major improvement in performance of DNS-lookup threaded programs,
and solves the "Mozilla tab serialization" problem.

No single-threaded applications need to be recompiled.  Multi-threaded
applications that reference "_res" to change resolver(3) options will
need to be recompiled, and ones which reference "h_errno" will also
if they desire the correct h_errno values.  If the applications already
understood that _res and h_errno were not thread-safe and had their own
locking, they will see no performance improvement but will not
actually break in any way.

Please note that when NSS modules are used, or when nsdispatch(3)
defaults to adding any lookups of its own to the individual libc
_nsdispatch() calls, those MUST be reentrant as well.
2004-02-25 21:03:46 +00:00

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/*-
* Copyright (c) 1983, 1987, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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) 1996 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.
*/
/*
* @(#)resolv.h 8.1 (Berkeley) 6/2/93
* From Id: resolv.h,v 8.12 1998/04/28 19:36:46 halley Exp $
* $FreeBSD$
*/
#ifndef _RESOLV_H_
#define _RESOLV_H_
#include <sys/param.h>
#include <sys/types.h>
#include <sys/cdefs.h>
#include <sys/socket.h>
#include <stdio.h>
/*
* Revision information. This is the release date in YYYYMMDD format.
* It can change every day so the right thing to do with it is use it
* in preprocessor commands such as "#if (__RES > 19931104)". Do not
* compare for equality; rather, use it to determine whether your resolver
* is new enough to contain a certain feature.
*/
#define __RES 19960801
/*
* Resolver configuration file.
* Normally not present, but may contain the address of the
* inital name server(s) to query and the domain search list.
*/
#ifndef _PATH_RESCONF
#define _PATH_RESCONF "/etc/resolv.conf"
#endif
/*
* Global defines and variables for resolver stub.
*/
#define MAXNS 3 /* max # name servers we'll track */
#define MAXDFLSRCH 3 /* # default domain levels to try */
#define MAXDNSRCH 6 /* max # domains in search path */
#define LOCALDOMAINPARTS 2 /* min levels in name that is "local" */
#define RES_TIMEOUT 5 /* min. seconds between retries */
#define MAXRESOLVSORT 10 /* number of net to sort on */
#define RES_MAXNDOTS 15 /* should reflect bit field size */
#define RES_MAXRETRANS 30 /* only for resolv.conf/RES_OPTIONS */
#define RES_MAXRETRY 5 /* only for resolv.conf/RES_OPTIONS */
struct __res_state {
int retrans; /* retransmition time interval */
int retry; /* number of times to retransmit */
u_long options; /* option flags - see below. */
int nscount; /* number of name servers */
struct sockaddr_in
nsaddr_list[MAXNS]; /* address of name server */
#define nsaddr nsaddr_list[0] /* for backward compatibility */
u_short id; /* current message id */
char *dnsrch[MAXDNSRCH+1]; /* components of domain to search */
char defdname[256]; /* default domain (deprecated) */
u_long pfcode; /* RES_PRF_ flags - see below. */
unsigned ndots:4; /* threshold for initial abs. query */
unsigned nsort:4; /* number of elements in sort_list[] */
char unused[3];
struct {
struct in_addr addr;
u_int32_t mask;
} sort_list[MAXRESOLVSORT];
char pad[72]; /* on an i386 this means 512b total */
};
/* for INET6 */
/*
* replacement of __res_state, separated to keep binary compatibility.
*/
struct __res_state_ext {
struct sockaddr_storage nsaddr_list[MAXNS];
struct {
int af; /* address family for addr, mask */
union {
struct in_addr ina;
struct in6_addr in6a;
} addr, mask;
} sort_list[MAXRESOLVSORT];
};
/*
* Resolver options (keep these in synch with res_debug.c, please)
*/
#define RES_INIT 0x00000001 /* address initialized */
#define RES_DEBUG 0x00000002 /* print debug messages */
#define RES_AAONLY 0x00000004 /* authoritative answers only (!IMPL)*/
#define RES_USEVC 0x00000008 /* use virtual circuit */
#define RES_PRIMARY 0x00000010 /* query primary server only (!IMPL) */
#define RES_IGNTC 0x00000020 /* ignore truncation errors */
#define RES_RECURSE 0x00000040 /* recursion desired */
#define RES_DEFNAMES 0x00000080 /* use default domain name */
#define RES_STAYOPEN 0x00000100 /* Keep TCP socket open */
#define RES_DNSRCH 0x00000200 /* search up local domain tree */
#define RES_INSECURE1 0x00000400 /* type 1 security disabled */
#define RES_INSECURE2 0x00000800 /* type 2 security disabled */
#define RES_NOALIASES 0x00001000 /* shuts off HOSTALIASES feature */
#define RES_USE_INET6 0x00002000 /* use/map IPv6 in gethostbyname() */
#define RES_NOTLDQUERY 0x00004000 /* Don't query TLD names */
/* KAME extensions: use higher bit to avoid conflict with ISC use */
#define RES_USE_EDNS0 0x40000000 /* use EDNS0 */
#define RES_DEFAULT (RES_RECURSE | RES_DEFNAMES | RES_DNSRCH)
/*
* Resolver "pfcode" values. Used by dig.
*/
#define RES_PRF_STATS 0x00000001
#define RES_PRF_UPDATE 0x00000002
#define RES_PRF_CLASS 0x00000004
#define RES_PRF_CMD 0x00000008
#define RES_PRF_QUES 0x00000010
#define RES_PRF_ANS 0x00000020
#define RES_PRF_AUTH 0x00000040
#define RES_PRF_ADD 0x00000080
#define RES_PRF_HEAD1 0x00000100
#define RES_PRF_HEAD2 0x00000200
#define RES_PRF_TTLID 0x00000400
#define RES_PRF_HEADX 0x00000800
#define RES_PRF_QUERY 0x00001000
#define RES_PRF_REPLY 0x00002000
#define RES_PRF_INIT 0x00004000
/* 0x00008000 */
typedef enum { res_goahead, res_nextns, res_modified, res_done, res_error }
res_sendhookact;
typedef res_sendhookact (*res_send_qhook)(struct sockaddr_in * const *ns,
const u_char **query,
int *querylen,
u_char *ans,
int anssiz,
int *resplen);
typedef res_sendhookact (*res_send_rhook)(const struct sockaddr_in *ns,
const u_char *query,
int querylen,
u_char *ans,
int anssiz,
int *resplen);
struct res_sym {
int number; /* Identifying number, like T_MX */
char * name; /* Its symbolic name, like "MX" */
char * humanname; /* Its fun name, like "mail exchanger" */
};
__BEGIN_DECLS
extern struct __res_state *___res(void);
extern struct __res_state_ext *___res_ext(void);
__END_DECLS
#define _res (*___res())
#define _res_ext (*___res_ext())
/* for INET6 */
extern struct __res_state_ext _res_ext;
extern const struct res_sym __p_class_syms[];
extern const struct res_sym __p_type_syms[];
/* Private routines shared between libc/net, named, nslookup and others. */
#define res_hnok __res_hnok
#define res_ownok __res_ownok
#define res_mailok __res_mailok
#define res_dnok __res_dnok
#define sym_ston __sym_ston
#define sym_ntos __sym_ntos
#define sym_ntop __sym_ntop
#define b64_ntop __b64_ntop
#define b64_pton __b64_pton
#define loc_ntoa __loc_ntoa
#define loc_aton __loc_aton
#define fp_resstat __fp_resstat
#define p_query __p_query
#define dn_skipname __dn_skipname
#define fp_resstat __fp_resstat
#define fp_query __fp_query
#define fp_nquery __fp_nquery
#define hostalias __hostalias
#define putlong __putlong
#define putshort __putshort
#define p_class __p_class
#define p_time __p_time
#define p_type __p_type
#define p_query __p_query
#define p_cdnname __p_cdnname
#define p_section __p_section
#define p_cdname __p_cdname
#define p_fqnname __p_fqnname
#define p_fqname __p_fqname
#define p_option __p_option
#define p_secstodate __p_secstodate
#define dn_count_labels __dn_count_labels
#define dn_comp __dn_comp
#define dn_expand __dn_expand
#define res_init __res_init
#define res_randomid __res_randomid
#define res_query __res_query
#define res_search __res_search
#define res_querydomain __res_querydomain
#define res_mkquery __res_mkquery
#define res_send __res_send
#define res_isourserver __res_isourserver
#define res_nameinquery __res_nameinquery
#define res_queriesmatch __res_queriesmatch
#define res_close __res_close
#define res_opt __res_opt
#define res_mkupdate __res_mkupdate
#define res_mkupdrec __res_mkupdrec
#define res_freeupdrec __res_freeupdrec
__BEGIN_DECLS
int res_hnok(const char *);
int res_ownok(const char *);
int res_mailok(const char *);
int res_dnok(const char *);
int sym_ston(const struct res_sym *, const char *, int *);
const char * sym_ntos(const struct res_sym *, int, int *);
const char * sym_ntop(const struct res_sym *, int, int *);
int b64_ntop(u_char const *, size_t, char *, size_t);
int b64_pton(char const *, u_char *, size_t);
int loc_aton(const char *, u_char *);
const char * loc_ntoa(const u_char *, char *);
int dn_skipname(const u_char *, const u_char *);
void fp_resstat(struct __res_state *, FILE *);
void fp_query(const u_char *, FILE *);
void fp_nquery(const u_char *, int, FILE *);
const char * hostalias(const char *);
void putlong(u_int32_t, u_char *);
void putshort(u_int16_t, u_char *);
const char * p_class(int);
const char * p_time(u_int32_t);
const char * p_type(int);
void p_query(const u_char *);
const u_char * p_cdnname(const u_char *, const u_char *, int, FILE *);
const u_char * p_cdname(const u_char *, const u_char *, FILE *);
const u_char * p_fqnname(const u_char *, const u_char *,
int, char *, int);
const u_char * p_fqname(const u_char *, const u_char *, FILE *);
const char * p_option(u_long);
char * p_secstodate(u_long);
int dn_count_labels(const char *);
int dn_comp(const char *, u_char *, int, u_char **, u_char **);
int dn_expand(const u_char *, const u_char *, const u_char *,
char *, int);
int res_init(void);
u_int res_randomid(void);
int res_query(const char *, int, int, u_char *, int);
int res_search(const char *, int, int, u_char *, int);
int res_querydomain(const char *, const char *, int, int,
u_char *, int);
int res_mkquery(int, const char *, int, int, const u_char *,
int, const u_char *, u_char *, int);
int res_send(const u_char *, int, u_char *, int);
int res_isourserver(const struct sockaddr_in *);
int res_nameinquery(const char *, int, int,
const u_char *, const u_char *);
int res_queriesmatch(const u_char *, const u_char *,
const u_char *, const u_char *);
void res_close(void);
int res_opt(int, u_char *, int, int);
const char * p_section(int, int);
/* XXX These must be exported for BIND4 compatibility. */
void __putlong(u_int32_t, u_char *);
void __putshort(u_int16_t, u_char *);
u_int32_t _getlong(const u_char *);
u_int16_t _getshort(const u_char *);
/* XXX The following depend on the ns_updrec typedef in arpa/nameser.h */
#ifdef _ARPA_NAMESER_H_
int res_update(ns_updrec *);
int res_mkupdate(ns_updrec *, u_char *, int);
ns_updrec * res_mkupdrec(int, const char *, u_int, u_int, u_long);
void res_freeupdrec(ns_updrec *);
#endif
__END_DECLS
#endif /* !_RESOLV_H_ */
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