ns_forw.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 864 行 · 第 1/2 页

#ifndef lint
static	char	*sccsid = "@(#)ns_forw.c	4.1	(ULTRIX)	7/2/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1984-1988 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
/*
 * Copyright (c) 1986 Regents of the University of California
 *	All Rights Reserved
 * static char sccsid[] = "@(#)ns_forw.c	4.26 (Berkeley) 3/28/88";
 */

/*
 * Modification History:
 *
 * 18-Jan-88	logcher
 *	Added BIND 4.7.2.
 *
 * 26-Jan-88	logcher
 *	Added BIND 4.7.3.
 *
 * 08-Mar-88	logcher
 *	Added a & to the bcmp with a sockaddr in ns_forw per bug fix
 *	from bind-test mailing list dated, 19-Feb-88
 *
 * 17-May-89	logcher
 *	Added BIND 4.8.
 */

#include <stdio.h>
#include <sys/param.h>
#include <sys/time.h>
#ifdef ULTRIXFUNC
#include <sys/stat.h>
#endif ULTRIXFUNC
#include <sys/socket.h>
#include <netinet/in.h>
#include <syslog.h>
#include <arpa/nameser.h>
#include "ns.h"
#include "db.h"

struct	qinfo *qhead = QINFO_NULL;	/* head of allocated queries */
struct	qinfo *retryqp = QINFO_NULL;	/* list of queries to retry */
struct	fwdinfo *fwdtab;		/* list of forwarding hosts */

int	nsid;				/* next forwarded query id */
extern int forward_only;		/* you are only a slave */
extern int errno;
extern short ns_port;

#ifdef AUTHEN
extern char *res_dotname_head();
#endif AUTHEN

time_t	retrytime();

#ifdef ULTRIXFUNC
struct fwdinfo *fwd_copy(fwd_src)
  struct fwdinfo *fwd_src;
{
	struct fwdinfo *fwd_dest = NULL;
	struct fwdinfo *src_ptr;
	struct fwdinfo *dest_ptr;
	struct fwdinfo *temp_ptr;

	for(src_ptr = fwd_src; src_ptr != NULL; src_ptr = src_ptr->next)
	{		
		if((temp_ptr = (struct fwdinfo *)
		    malloc(sizeof(struct fwdinfo))) == NULL)
			return(NULL);

		if(fwd_dest == NULL) {
			fwd_dest = dest_ptr = temp_ptr;
		} else {
			dest_ptr->next = temp_ptr;
			dest_ptr = temp_ptr;			
		}
		*dest_ptr = *src_ptr;
		dest_ptr->next = NULL;
	}
	return(fwd_dest);
}
#endif ULTRIXFUNC


/*
 * Forward the query to get the answer since its not in the database.
 * Returns FW_OK if a request struct is allocated and the query sent.
 * Returns FW_DUP if this is a duplicate of a pending request. 
 * Returns FW_NOSERVER if there were no addresses for the nameservers.
 * Returns FW_SERVFAIL on malloc error.
 * (no action is taken on errors and qpp is not filled in.)
 */
#ifdef AUTHEN
ns_forw(nsp, msg, msglen, fp, qsp, dfd, qpp, query_in, query_out, authentype_in, authenver_in, authentype_out, authenver_out, ns_ad, query_dname, query_type, query_class)
	struct databuf *nsp[];
	char *msg;
	int msglen;
	struct sockaddr_in *fp;
	struct qstream *qsp;
	int dfd;
	struct qinfo **qpp;
	int query_in;
	int query_out;
	int authentype_in;
	int authenver_in;
	int authentype_out;
	int authenver_out;
	AUTH_DAT ns_ad;
	char *query_dname;
	int query_type;
	int query_class;
{
#else AUTHEN
ns_forw(nsp, msg, msglen, fp, qsp, dfd, qpp)
	struct databuf *nsp[];
	char *msg;
	int msglen;
	struct sockaddr_in *fp;
	struct qstream *qsp;
	int dfd;
	struct qinfo **qpp;
{
#endif AUTHEN
	register struct qinfo *qp;
	HEADER *hp;
	u_short id;
	extern char *calloc();

#ifdef AUTHEN
	char *krbnameptr;
	char *dnameptr;
	int authen_len;
#endif AUTHEN

#ifdef DEBUG
	if (debug >= 3)
		fprintf(ddt,"ns_forw()\n");
#endif

	/* Don't forward if we're already working on it. */
	hp = (HEADER *) msg;
	id = hp->id;
	hp->rd = 0;
	/* Look at them all */
	for (qp = qhead; qp!=QINFO_NULL; qp = qp->q_link) {
		if (qp->q_id == id &&
		    bcmp((char *)&qp->q_from, fp, sizeof(qp->q_from)) == 0 &&
		    (qp->q_cmsglen == 0 && qp->q_msglen == msglen &&
		     bcmp((char *)qp->q_msg+2, msg+2, msglen-2) == 0) ||
		    (qp->q_cmsglen == msglen &&
		     bcmp((char *)qp->q_cmsg+2, msg+2, msglen-2) == 0)) {
#ifdef DEBUG
			if (debug >= 3)
				fprintf(ddt,"forw: dropped DUP id=%d\n", ntohs(id));
#endif
#ifdef STATS
			stats[S_DUPQUERIES].cnt++;
#endif
			return (FW_DUP);
		}
	}

	qp = qnew();
#ifdef ULTRIXFUNC
	if (nslookup(nsp, qp) == 0 && !(forward_only && fwdtab)) {
#else ULTRIXFUNC
	if (nslookup(nsp, qp) == 0) {
#endif ULTRIXFUNC

#ifdef DEBUG
		if (debug >= 2)
			fprintf(ddt,"forw: no nameservers found\n");
#endif
		qfree(qp);
		hp->rd = 1;
		return (FW_NOSERVER);
	}
	qp->q_stream = qsp;
	qp->q_curaddr = 0;
#ifdef ULTRIXFUNC
	qp->q_fwd = fwd_copy(fwdtab);
	qp->q_fwdorig = qp->q_fwd;
#else ULTRIXFUNC
	qp->q_fwd = fwdtab;
#endif ULTRIXFUNC
	qp->q_dfd = dfd;
	qp->q_id = id;
#ifdef AUTHEN
	qp->q_ad = ns_ad;
	qp->q_type_in = query_in;
	qp->q_type_out = query_out;
	qp->q_authentype_in =  authentype_in;
	qp->q_authenver_in = authenver_in;
	qp->q_authentype_out = authentype_out;
	qp->q_authenver_out = authenver_out;
	strcpy(qp->q_dname, query_dname);
	qp->q_type = query_type;
	qp->q_class = query_class;
	strcpy(qp->q_dname_curr, query_dname);
	qp->q_type_curr = query_type;
	qp->q_class_curr = query_class;
#endif AUTHEN
	hp->id = qp->q_nsid = htons((u_short)++nsid);
	hp->ancount = 0;
	hp->nscount = 0;
	hp->arcount = 0;
	if (qp->q_fwd)
		hp->rd = 1;
	else
		qp->q_addr[0].stime = tt;
	qp->q_from = *fp;
#ifdef AUTHEN
	if ((qp->q_msg = malloc(BUFSIZ)) == NULL) {
		syslog(LOG_ERR, "forw: %m");
		qfree(qp);
		return (FW_SERVFAIL);
	}
#else AUTHEN
	if ((qp->q_msg = malloc((unsigned)msglen)) == NULL) {
		syslog(LOG_ERR, "forw: %m");
		qfree(qp);
		return (FW_SERVFAIL);
	}
#endif AUTHEN
	bcopy(msg, qp->q_msg, qp->q_msglen = msglen);
#ifdef AUTHEN
	if((hp->opcode == AQUERY && authentype_out == AUTH_KRB &&
		       authenver_out == ONE)) {
		krbnameptr = res_dotname_head(Q_NEXTNAME(qp, 0));
		dnameptr = query_dname;
		if (query_type != T_SOA && query_type != T_AXFR)
			res_dotname_rmhead(&dnameptr);

		hp->arcount = htons(1);

		if((authen_len = res_mkl_krbcred(ONE,
						 "named",
						 krbnameptr,
						 Q_NEXTCRED(qp,0),
						 msg,
						 msg + msglen,
						 BUFSIZ - msglen,
						 dnameptr, query_type,
						 query_class)) < RET_OK) {
			free(krbnameptr);
			qfree(qp);
			return(FW_SERVFAIL);
		}
		free(krbnameptr);
		msglen += authen_len;
	}

#endif AUTHEN

#ifdef ULTRIXFUNC
	schedretry(qp, qp->q_fwd ? (2*RETRYBASE): retrytime(qp) );
#else ULTRIXFUNC
	schedretry(qp, retrytime(qp));
#endif ULTRIXFUNC

#ifdef DEBUG
	if (debug)
#ifdef ULTRIXFUNC
		fprintf(ddt,
		   "forw: forw -> %s %d (%d) nsid=%d id=%d %dms retry %d sec\n",
			inet_ntoa(Q_NEXTADDR(qp,0)->sin_addr),
			ds, ntohs(Q_NEXTADDR(qp,0)->sin_port),
			ntohs(qp->q_nsid), ntohs(qp->q_id),
			((qp->q_addr[0].nsdata) ? qp->q_addr[0].nsdata->d_nstime: -1),
			qp->q_time - tt.tv_sec);
#else ULTRIXFUNC
		fprintf(ddt,
		   "forw: forw -> %s %d (%d) nsid=%d id=%d %dms retry %d sec\n",
			inet_ntoa(Q_NEXTADDR(qp,0)->sin_addr),
			ds, ntohs(Q_NEXTADDR(qp,0)->sin_port),
			ntohs(qp->q_nsid), ntohs(qp->q_id),
			qp->q_addr[0].nsdata->d_nstime,
			qp->q_time - tt.tv_sec);
#endif ULTRIXFUNC
	if ( debug >= 10)
		fp_query(msg, ddt);
#endif
	if (sendto(ds, msg, msglen, 0, (struct sockaddr *)Q_NEXTADDR(qp,0),
		   sizeof(struct sockaddr_in)) < 0){
#ifdef DEBUG
	if (debug >= 5)
			fprintf(ddt,"error returning msg errno=%d\n",errno);
#endif
	}
#ifdef STATS
	stats[S_OUTPKTS].cnt++;
#endif
	if (qpp)
		*qpp = qp;
	hp->rd = 0;
	return (0);
}


/*
 * Lookup the address for each nameserver in `nsp' and add it to
 * the list saved in the qinfo structure.
 */
nslookup(nsp, qp)
	struct databuf *nsp[];
	register struct qinfo *qp;
{
	register struct namebuf *np;
	register struct databuf *dp, *nsdp;
	register struct qserv *qs;
	register int n, i;
	struct hashbuf *tmphtp;
	char *dname, *fname;
	int oldn, naddr, class, found_arr;
	time_t curtime;
	int qcomp();

#ifdef DEBUG
	if (debug >= 3)
		fprintf(ddt,"nslookup(nsp=x%x,qp=x%x)\n",nsp,qp);
#endif

	naddr = n = qp->q_naddr;
	curtime = (u_long) tt.tv_sec;
	while ((nsdp = *nsp++) != NULL) {
		class = nsdp->d_class;
		dname = nsdp->d_data;
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"nslookup: NS %s c%d t%d (x%x)\n",
				dname, class, nsdp->d_type, nsdp->d_flags);
#endif
		/* don't put in people we have tried */
		for (i = 0; i < qp->q_nusedns; i++)
			if (qp->q_usedns[i] == nsdp) {
#ifdef DEBUG
				if (debug >= 2)
fprintf(ddt, "skipping used NS w/name %s\n", nsdp->d_data);
#endif DEBUG
				goto skipserver;
			}

		tmphtp = ((nsdp->d_flags & DB_F_HINT) ? fcachetab : hashtab);
		np = nlookup(dname, &tmphtp, &fname, 1);
		if (np == NULL || fname != dname) {
#ifdef DEBUG
			if (debug >= 3)
			    fprintf(ddt,"%s: not found %s %x\n",dname,fname,np);
#endif
			continue;
		}
		found_arr = 0;
		oldn = n;
		/* look for name server addresses */
		for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
			if (dp->d_type != T_A || dp->d_class != class)
				continue;
			/*
			 * Don't use records that may become invalid to
			 * reference later when we do the rtt computation.
			 * Never delete our safety-belt information!
			 */
			if ((dp->d_zone == 0) &&
			    (dp->d_ttl < (curtime+900)) &&
			    !(dp->d_flags & DB_F_HINT) )
		        {
#ifdef DEBUG
				if (debug >= 3)
					fprintf(ddt,"nslookup: stale entry '%s'\n",
					    np->n_dname);
#endif
				/* Cache invalidate the NS RR's */
				if (dp->d_ttl < curtime)
					delete_all(np, class, T_A);
				n = oldn;
				break;
			}

			found_arr++;
			/* don't put in duplicates */
			qs = qp->q_addr;
			for (i = 0; i < n; i++, qs++)
				if (bcmp((char *)&qs->ns_addr.sin_addr,
				    dp->d_data, sizeof(struct in_addr)) == 0)
					goto skipaddr;
			qs->ns_addr.sin_family = AF_INET;
			qs->ns_addr.sin_port = (u_short)ns_port;
			qs->ns_addr.sin_addr = 
				    *(struct in_addr *)dp->d_data;
			qs->ns = nsdp;
			qs->nsdata = dp;
			qp->q_addr[n].nretry = 0;
#ifdef AUTHEN
			strcpy(qp->q_addr[n].ns_name,dname);
			qp->authen_msglen = 0;
#endif AUTHEN
			n++;
			if (n >= NSMAX)
				goto out;
	skipaddr:	;
		}
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"nslookup: %d ns addrs\n", n);
#endif