host.c

早期freebsd实现

/*
 * Copyright (c) 1985, 1989 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
 * Originally, this program came from Rutgers University, however it
 * is based on nslookup and other pieces of named tools, so it needs
 * that copyright notice.
 */

/*
 * Rewritten by Eric Wassenaar, Nikhef-H, <[e-mail]>
 *
 * The officially maintained source of this program is available
 * via anonymous ftp from machine 'ftp.nikhef.nl' [192.16.199.1]
 * in the directory '/pub/network' as 'host.tar.Z'
 *
 * You are kindly requested to report bugs and make suggestions
 * for improvements to the author at the given email address,
 * and to not re-distribute your own modifications to others.
 */

#ifndef lint
static char Version[] = "@(#)host.c	[e-mail] (Eric Wassenaar) 930926";
#endif

#if defined(apollo) && defined(lint)
#define __attribute(x)
#endif

#define justfun			/* this is only for fun */
#undef  obsolete		/* old code left as a reminder */
#undef  notyet			/* new code for possible future use */

/*
 *			New features
 *
 * - Major overhaul of the entire code.
 * - Very rigid error checking, with more verbose error messages.
 * - Zone listing section completely rewritten.
 * - It is now possible to do recursive listings into delegated zones.
 * - Maintain resource record statistics during zone listings.
 * - Maintain count of hosts during zone listings.
 * - Check for various extraneous conditions during zone listings.
 * - Exploit multiple server addresses if available.
 * - Option to exploit only primary server for zone transfers.
 * - Option to exclude info from names that do not reside in a zone.
 * - Implement timeout handling during connect and read.
 * - Write resource record output to optional logfile.
 * - Special MB tracing by recursively expanding MR and MG records.
 * - Special mode to check SOA records at each nameserver for a zone.
 * - Special mode to check reverse mappings of host addresses.
 * - Extended syntax allows multiple arguments on command line or stdin.
 * - Configurable default options in HOST_DEFAULTS environment variable.
 * - Code is extensively documented.
 */

/*
 *			Publication history
 *
 * This information has been moved to the RELEASE_NOTES file.
 */

/*
 *			Compilation options
 *
 * This program usually compiles without special compilation options,
 * but for some platforms you may have to define special settings.
 * See the Makefile and the header file port.h for details.
 */

/*
 *			Miscellaneous notes
 *
 * This program should be linked explicitly with the BIND resolver library
 * in case the default gethostbyname() or gethostbyaddr() routines use a
 * non-standard strategy for retrieving information. These functions in the
 * resolver library call on the nameserver, and fall back on the hosts file
 * only if no nameserver is running (ECONNREFUSED).
 *
 * You may also want to link this program with the BIND resolver library if
 * your default library has not been compiled with DEBUG printout enabled.
 *
 * The version of the resolver should be BIND 4.8.2 or later. The crucial
 * include files are <netdb.h>, (resolv.h>, <arpa/nameser.h>. These files
 * are assumed to be present in the /usr/include directory.
 *
 * The resolver code depends on the definition of the BSD pre-processor
 * variable. This variable is usually defined in the file <sys/param.h>.
 *
 * The definition of this variable determines the method how to handle
 * datagram connections. This may not work properly on all platforms.
 *
 * The hostent struct defined in <netdb.h> is assumed to handle multiple
 * addresses in h_addr_list[]. Usually this is true if BSD >= 43.
 *
 * Your version of the nameserver may not handle queries about top-level
 * zones properly. It needs a patch if it appends the default domain
 * to single names for which it has no data cached. A fix for this is
 * available.
 *
 * The treatment of TXT records has changed from 4.8.2 to 4.8.3. Formerly,
 * the data consisted simply of the text string. Now, the text string is
 * preceded by the character count with a maximum of 255, and multiple
 * strings are embedded if the total character count exceeds 255.
 * We handle only the new situation in this program, assuming that nobody
 * uses TXT records before 4.8.3 (unfortunately this is not always true:
 * current vendor supplied software may sometimes be even pre-BIND 4.8.2).
 *
 * Note that in 4.8.3 PACKETSZ from nameser.h is still at 512, which is
 * the maximum possible packet size for datagrams, whereas MAXDATA from
 * db.h has increased from 256 to 2048. The resolver defines MAXPACKET
 * as 1024. The nameserver reads queries in a buffer of size BUFSIZ.
 *
 * The gethostbyname() routine in 4.8.3 interprets dotted quads (if not
 * terminated with a dot) and simulates a gethostbyaddr(), but we will
 * not rely on it, and handle dotted quads ourselves.
 *
 * On some systems a bug in the _doprnt() routine exists which prevents
 * printf("%.*s", n, string) to be printed correctly if n == 0.
 *
 * This program has not been optimized for speed. Especially the memory
 * management is simple and straightforward.
 */

/*
 *			Terminology used
 *
 * Gateway hosts.
 * These are hosts that have more than one address registered under
 * the same name. Obviously we cannot recognize a gateway host if it
 * has different names associated with its different addresses.
 *
 * Duplicate hosts.
 * These are non-gateway hosts of which the address was found earlier
 * but with a different name, possibly in a totally different zone.
 * Such hosts should not be counted again in the overall host count.
 * This situation notably occurs in e.g. the "ac.uk" domain which has
 * many names registered in both the long and the abbreviated form,
 * such as 'host.department.university.ac.uk' and 'host.dept.un.ac.uk'.
 * This is probably not an error per se. It is an error if some domain
 * has registered a foreign address under a name within its own domain.
 * To recognize duplicate hosts when traversing many zones, we have to
 * maintain a global list of host addresses. To simplify things, only
 * single-address hosts are handled as such.
 *
 * Extrazone hosts.
 * These are hosts which belong to a zone but which are not residing
 * directly within the zone under consideration and which are not
 * glue records for a delegated zone of the given zone. E.g. if we are
 * processing the zone 'bar' and find 'host.foo.bar' but 'foo.bar' is not
 * an NS registered delegated zone of 'bar' then it is considered to be
 * an extrazone host. This is not necessarily an error, but it could be.
 *
 * Lame delegations.
 * If we query the SOA record of a zone at a supposedly authoritative
 * nameserver for that zone (listed in the NS records for the zone),
 * the SOA record should be present and the answer authoritative.
 * If not, we flag a lame delegation of the zone to that nameserver.
 * This may need refinement in some special cases.
 * A lame delegation is also flagged if we discover that a nameserver
 * mentioned in an NS record does not exist when looking up its address.
 */

/*
 *		Usage: host [options] name [server]
 *		Usage: host [options] -x [name ...]
 *		Usage: host [options] -X server [name ...]
 *
 * Regular command line options:
 * ----------------------------
 *
 * -t type	specify query type; default is T_A for normal mode
 *
 * -a		specify query type T_ANY
 *
 * -v		print verbose messages (-vv is very verbose)
 *
 * -d		print debugging output (-dd prints even more)
 *
 * Special mode options.
 * --------------------
 *
 * -l		special mode to generate zone listing for a zone
 *
 * -L level	do recursive zone listing/checking this level deep
 *
 * -p		use primary nameserver of zone for zone transfers
 *
 * -S		print zone resource record statistics
 *
 * -H		special mode to count hosts residing in a zone
 *
 * -G		same as -H but lists gateway hosts in addition
 *
 * -E		same as -H but lists extrazone hosts in addition
 *
 * -D		same as -H but lists duplicate hosts in addition
 *
 * -C		special mode to check SOA records for a zone
 *
 * -A		special mode to check reverse mappings of host addresses
 *
 * Miscellaneous options.
 * ---------------------
 *
 * -e		exclude info from names that do not reside in the zone
 *
 * -f file	log resource record output also in given file
 *
 * -F file	same as -f, but exchange role of stdout and logfile
 *
 * -i		generate reverse in-addr.arpa query for dotted quad
 *
 * -q		be quiet about some non-fatal errors
 *
 * -T		print ttl value or MX pref during non-verbose output
 *
 * Seldom used options.
 * -------------------
 *
 * -c class	specify query class; default is C_IN
 *
 * -m		specify query type T_MAILB and trace MB records
 *
 * -o		suppress resource record output to stdout
 *
 * -r		do not use recursion when querying nameserver
 *
 * -R		repeatedly add search domains to qualify queryname
 *
 * -s secs	specify timeout value in seconds; default is 2 * 5
 *
 * -u		use virtual circuit instead of datagram for queries
 *
 * -w		wait until nameserver becomes available
 *
 * Undocumented options. (Experimental, subject to change)
 * --------------------
 *
 * -g length	only select names that are at least this long
 *
 * -B		enforce full BIND behaviour during DNSRCH
 *
 * -I chars	print illegal resource record names, but allow chars
 *
 * -M		special mode to list mailable delegated zones of zone
 */

static char Usage[] =
"\
Usage:      host [-v] [-a] [-t querytype] [options]  name  [server]\n\
Listing:    host [-v] [-a] [-t querytype] [options]  -l zone  [server]\n\
Hostcount:  host [-v] [options] -H [-D] [-E] [-G] zone\n\
Check soa:  host [-v] [options] -C zone\n\
Addrcheck:  host [-v] [options] -A host\n\
List options:    [-L level] [-S] [-p]\n\
Common options:  [-d] [-e] [-f logfile] [-F logfile] [-i] [-q] [-T]\n\
Other options:   [-c class] [-m] [-o] [-r] [-R] [-s secs] [-u] [-w]\n\
Extended usage:  [-x [name ...]] [-X server [name ...]]\
";

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>

#include <sys/types.h>		/* not always automatically included */
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#undef NOERROR			/* in <sys/streams.h> on solaris 2.x */
#include <arpa/nameser.h>
#include <resolv.h>

#include "type.h"		/* types should be in <arpa/nameser.h> */
#include "exit.h"		/* exit codes come from <sysexits.h> */
#include "port.h"		/* various portability definitions */

#define input			/* read-only input parameter */
#define output			/* modified output parameter */

typedef int	bool;		/* boolean type */
#define TRUE	1
#define FALSE	0

#ifndef NO_DATA
#define NO_DATA	NO_ADDRESS	/* used here only in case authoritative */
#endif

#define NO_RREC	(NO_DATA + 1)	/* used for non-authoritative NO_DATA */
#define NO_HOST	(NO_DATA + 2)	/* used for non-authoritative HOST_NOT_FOUND */

#define T_NONE	0		/* yet unspecified resource record type */
#define T_FIRST	T_A		/* first possible type in resource record */
#define T_LAST	(T_AXFR - 1)	/* last  possible type in resource record */

#define MAXADDRS 35		/* max address count from gethostnamadr.c */

#define NOT_DOTTED_QUAD ((ipaddr_t)-1)
#define LOCALHOST_ADDR	((ipaddr_t)0x7f000001)

#define is_space(c)	(isascii(c) && isspace(c))
#define is_alnum(c)	(isascii(c) && isalnum(c))
#define bitset(a,b)	(((a) & (b)) != 0)
#define sameword(a,b)	(strcasecmp(a,b) == 0)
#define samepart(a,b)	(strncasecmp(a,b,strlen(b)) == 0)
#define fakename(a)	(samepart(a,"localhost.") || samepart(a,"loopback."))
#define fakeaddr(a)	(((a) == 0) || ((a) == htonl(LOCALHOST_ADDR)))
#define incopy(a)	*((struct in_addr *)a)

#define newlist(a,n,t)	(t *)xalloc((ptr_t *)a, (siz_t)((n)*sizeof(t)))
#define newstring(a)	(char *)xalloc((ptr_t *)NULL, (siz_t)(strlen(a)+1))
#define newstr(a)	strcpy(newstring(a), a)
#define xfree(a)	(void) free((ptr_t *)a)
#define strlength(a)	(int)strlen(a)

#if PACKETSZ > 1024
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 1024
#endif

typedef union {
	HEADER header;
	u_char packet[MAXPACKET];
} querybuf;

#ifdef lint
#define EXTERN
#else
#define EXTERN extern
#endif

EXTERN int errno;
EXTERN int h_errno;		/* defined in gethostnamadr.c */
EXTERN res_state_t _res;	/* defined in res_init.c */

int Errors = 0;			/* global error count */

int record_stats[T_ANY+1];	/* count of resource records per type */

char cnamebuf[MAXDNAME+1];
char *cname = NULL;		/* name to which CNAME is aliased */

char mnamebuf[MAXDNAME+1];
char *mname = NULL;		/* name to which MR or MG is aliased */

char soanamebuf[MAXDNAME+1];
char *soaname = NULL;		/* domain name of SOA record */

char subnamebuf[MAXDNAME+1];
char *subname = NULL;		/* domain name of NS record */

char adrnamebuf[MAXDNAME+1];
char *adrname = NULL;		/* domain name of A record */

ipaddr_t address;		/* internet address of A record */

char serverbuf[MAXDNAME+1];
char *server = NULL;		/* name of explicit server to query */

char realnamebuf[2*MAXDNAME+2];
char *realname = NULL;		/* the actual name that was queried */

char *logfilename = NULL;	/* name of log file */
FILE *logfile = NULL;		/* default is stdout only */
bool logexchange = FALSE;	/* exchange role of logfile and stdout */

char *illegal = NULL;		/* give warning about illegal domain names */

char *queryname = NULL;		/* the name about which to query */
int querytype = T_NONE;		/* the type of the query */
int queryclass = C_IN;		/* the class of the query */

int debug = 0;			/* print resolver debugging output */
int verbose = 0;		/* verbose mode for extra output */
#ifdef justfun
int namelen = 0;		/* select records exceeding this length */
#endif
int recursive = 0;		/* recursive listmode maximum level */

bool quiet = FALSE;		/* suppress non-fatal warning messages */
bool reverse = FALSE;		/* generate reverse in-addr.arpa queries */
bool primary = FALSE;		/* use primary server for zone transfers */
bool suppress = FALSE;		/* suppress resource record output */
bool ttlprint = FALSE;		/* print ttl value in non-verbose mode */
bool waitmode = FALSE;		/* wait until server becomes available */
bool mailmode = FALSE;		/* trace MG and MR into MB records */
bool addrmode = FALSE;		/* check reverse mappings of addresses */
bool listmode = FALSE;		/* generate zone listing of a zone */
bool hostmode = FALSE;		/* count real hosts residing within zone */
bool duplmode = FALSE;		/* list duplicate hosts within zone */
bool extrmode = FALSE;		/* list extrazone hosts within zone */
bool gatemode = FALSE;		/* list gateway hosts within zone */
bool checkmode = FALSE;		/* check SOA records at each nameserver */
bool mxrecmode = FALSE;		/* list MX records for each delegated zone */
bool exclusive = FALSE;		/* exclude records that are not in zone */
bool statistics = FALSE;	/* print resource record statistics */
bool bindcompat = FALSE;	/* enforce full BIND DNSRCH compatibility */

char **optargv = NULL;		/* argument list including default options */
int optargc = 0;		/* number of arguments in new argument list */

/* extern */
ipaddr_t inet_addr	PROTO((char *));
char *inet_ntoa		PROTO((struct in_addr));
char *hostalias		PROTO((char *));
char *getenv		PROTO((char *));
char *strcpy		PROTO((char *, char *));
char *rindex		PROTO((char *, char));
char *index		PROTO((char *, char));
ptr_t *malloc		PROTO((siz_t));
ptr_t *realloc		PROTO((ptr_t *, siz_t));
void exit		PROTO((int));

/* main.c */
int main		PROTO((int, char **));
void set_defaults	PROTO((char *, int, char **));
int process_argv	PROTO((int, char **));
int process_file	PROTO((FILE *));
int process_name	PROTO((char *));
int execute_name	PROTO((char *));
bool execute		PROTO((ipaddr_t));
void set_server		PROTO((char *));
void fatal		PROTO((char *, ...));
void errmsg		PROTO((char *, ...));

/* info.c */
bool get_hostinfo	PROTO((char *));
bool get_domaininfo	PROTO((char *, char *));
int get_info		PROTO((querybuf *, char *, int, int));
bool print_info		PROTO((querybuf *, int, char *, bool));
void doprintf		PROTO((char *, ...));
u_char *print_rrec	PROTO((char *, u_char *, u_char *, u_char *, bool));
u_char *skip_qrec	PROTO((char *, u_char *, u_char *, u_char *));

/* list.c */
bool list_zone		PROTO((char *));
bool find_servers	PROTO((char *));
bool get_servers	PROTO((char *));
bool get_nsinfo		PROTO((querybuf *, int, char *));
bool transfer_zone	PROTO((char *, int, struct in_addr, char *));
bool get_zone		PROTO((char *, int, struct in_addr, char *));
bool get_mxrec		PROTO((char *));
char *get_primary	PROTO((char *));
bool check_zone		PROTO((char *));
bool get_soainfo	PROTO((querybuf *, int, char *));
void check_soa		PROTO((querybuf *, char *));
bool check_dupl		PROTO((ipaddr_t));

/* addr.c */
bool check_addr		PROTO((char *));
bool check_name		PROTO((ipaddr_t));

/* util.c */
int parse_type		PROTO((char *));
int parse_class		PROTO((char *));
char *in_addr_arpa	PROTO((char *));
void print_host		PROTO((char *, struct hostent *));
void show_res		PROTO((void));
void print_statistics	PROTO((char *, int, int));
void clear_statistics	PROTO((void));
void show_types		PROTO((char *, int, int));
void ns_error		PROTO((char *, int, int));
char *decode_error	PROTO((int));
void print_status	PROTO((querybuf *));
void pr_error		PROTO((char *, ...));
void pr_warning		PROTO((char *, ...));
bool want_type		PROTO((int, int));
bool want_class		PROTO((int, int));
bool indomain		PROTO((char *, char *, bool));
bool samedomain		PROTO((char *, char *, bool));
bool gluerecord		PROTO((char *, char *, char **, int));
char *pr_dotname	PROTO((char *));
char *pr_type		PROTO((int));
char *pr_class		PROTO((int));
int expand_name		PROTO((char *, int, u_char *, u_char *, u_char *, char *));
int check_size		PROTO((char *, int, u_char *, u_char *, u_char *, int));
bool valid_name		PROTO((char *, bool));

/* misc.c */
ptr_t *xalloc		PROTO((ptr_t *, siz_t));
char *itoa		PROTO((int));
char *stoa		PROTO((u_char *, int));

/* send.c */
#ifdef HOST_RES_SEND
int res_send		PROTO((char *, int, char *, int));
#endif /*HOST_RES_SEND*/
int _res_connect	PROTO((int, struct sockaddr_in *, int));
int _res_write		PROTO((int, char *, int));
int _res_read		PROTO((int, char *, int));
void _res_setaddr	PROTO((struct sockaddr_in *, char *));
void _res_perror	PROTO((char *));

/* vers.c */
extern char *version;