580 lines
14 KiB
C
580 lines
14 KiB
C
/*-
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* Copyright (c) 1986 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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/*static char sccsid[] = "from: @(#)ns_forw.c 4.32 (Berkeley) 3/3/91";*/
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static char rcsid[] = "$Id: ns_forw.c,v 1.2 1993/08/01 17:57:47 mycroft Exp $";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <syslog.h>
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#include <arpa/nameser.h>
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#include <resolv.h>
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#include <stdio.h>
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#include "ns.h"
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#include "db.h"
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struct qinfo *qhead = QINFO_NULL; /* head of allocated queries */
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struct qinfo *retryqp = QINFO_NULL; /* list of queries to retry */
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struct fwdinfo *fwdtab; /* list of forwarding hosts */
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int nsid; /* next forwarded query id */
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extern int forward_only; /* you are only a slave */
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extern int errno;
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extern u_short ns_port;
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time_t retrytime();
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/*
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* Forward the query to get the answer since its not in the database.
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* Returns FW_OK if a request struct is allocated and the query sent.
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* Returns FW_DUP if this is a duplicate of a pending request.
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* Returns FW_NOSERVER if there were no addresses for the nameservers.
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* Returns FW_SERVFAIL on malloc error.
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* (no action is taken on errors and qpp is not filled in.)
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*/
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ns_forw(nsp, msg, msglen, fp, qsp, dfd, qpp)
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struct databuf *nsp[];
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char *msg;
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int msglen;
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struct sockaddr_in *fp;
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struct qstream *qsp;
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int dfd;
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struct qinfo **qpp;
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{
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register struct qinfo *qp;
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HEADER *hp;
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u_short id;
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extern char *calloc();
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"ns_forw()\n");
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#endif
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/* Don't forward if we're already working on it. */
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hp = (HEADER *) msg;
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id = hp->id;
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/* Look at them all */
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for (qp = qhead; qp!=QINFO_NULL; qp = qp->q_link) {
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if (qp->q_id == id &&
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bcmp((char *)&qp->q_from, fp, sizeof(qp->q_from)) == 0 &&
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((qp->q_cmsglen == 0 && qp->q_msglen == msglen &&
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bcmp((char *)qp->q_msg+2, msg+2, msglen-2) == 0) ||
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(qp->q_cmsglen == msglen &&
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bcmp((char *)qp->q_cmsg+2, msg+2, msglen-2) == 0))) {
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"forw: dropped DUP id=%d\n", ntohs(id));
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#endif
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#ifdef STATS
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stats[S_DUPQUERIES].cnt++;
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#endif
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return (FW_DUP);
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}
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}
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qp = qnew();
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if (nslookup(nsp, qp) == 0) {
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#ifdef DEBUG
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if (debug >= 2)
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fprintf(ddt,"forw: no nameservers found\n");
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#endif
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qfree(qp);
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return (FW_NOSERVER);
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}
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qp->q_stream = qsp;
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qp->q_curaddr = 0;
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qp->q_fwd = fwdtab;
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qp->q_dfd = dfd;
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qp->q_id = id;
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hp->id = qp->q_nsid = htons((u_short)++nsid);
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hp->ancount = 0;
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hp->nscount = 0;
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hp->arcount = 0;
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qp->q_from = *fp;
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if ((qp->q_msg = malloc((unsigned)msglen)) == NULL) {
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syslog(LOG_ERR, "forw: %m");
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qfree(qp);
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return (FW_SERVFAIL);
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}
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bcopy(msg, qp->q_msg, qp->q_msglen = msglen);
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if (!qp->q_fwd) {
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hp->rd = 0;
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qp->q_addr[0].stime = tt;
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}
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schedretry(qp, retrytime(qp));
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#ifdef DEBUG
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if (debug)
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fprintf(ddt,
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"forw: forw -> %s %d (%d) nsid=%d id=%d %dms retry %d sec\n",
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inet_ntoa(Q_NEXTADDR(qp,0)->sin_addr),
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ds, ntohs(Q_NEXTADDR(qp,0)->sin_port),
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ntohs(qp->q_nsid), ntohs(qp->q_id),
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qp->q_addr[0].nsdata->d_nstime,
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qp->q_time - tt.tv_sec);
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if ( debug >= 10)
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fp_query(msg, ddt);
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#endif
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if (sendto(ds, msg, msglen, 0, (struct sockaddr *)Q_NEXTADDR(qp,0),
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sizeof(struct sockaddr_in)) < 0){
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#ifdef DEBUG
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if (debug >= 5)
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fprintf(ddt,"error returning msg errno=%d\n",errno);
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#endif
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}
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#ifdef STATS
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stats[S_OUTPKTS].cnt++;
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#endif
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if (qpp)
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*qpp = qp;
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hp->rd = 1;
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return (0);
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}
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/*
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* Lookup the address for each nameserver in `nsp' and add it to
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* the list saved in the qinfo structure.
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*/
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nslookup(nsp, qp)
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struct databuf *nsp[];
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register struct qinfo *qp;
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{
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register struct namebuf *np;
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register struct databuf *dp, *nsdp;
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register struct qserv *qs;
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register int n, i;
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struct hashbuf *tmphtp;
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char *dname, *fname;
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int oldn, naddr, class, found_arr;
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time_t curtime;
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int qcomp();
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"nslookup(nsp=x%x,qp=x%x)\n",nsp,qp);
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#endif
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naddr = n = qp->q_naddr;
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curtime = (u_long) tt.tv_sec;
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while ((nsdp = *nsp++) != NULL) {
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class = nsdp->d_class;
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dname = nsdp->d_data;
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"nslookup: NS %s c%d t%d (x%x)\n",
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dname, class, nsdp->d_type, nsdp->d_flags);
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#endif
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/* don't put in people we have tried */
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for (i = 0; i < qp->q_nusedns; i++)
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if (qp->q_usedns[i] == nsdp) {
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#ifdef DEBUG
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if (debug >= 2)
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fprintf(ddt, "skipping used NS w/name %s\n", nsdp->d_data);
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#endif DEBUG
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goto skipserver;
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}
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tmphtp = ((nsdp->d_flags & DB_F_HINT) ? fcachetab : hashtab);
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np = nlookup(dname, &tmphtp, &fname, 1);
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if (np == NULL || fname != dname) {
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"%s: not found %s %x\n",dname,fname,np);
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#endif
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continue;
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}
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found_arr = 0;
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oldn = n;
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/* look for name server addresses */
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for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
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if (dp->d_type != T_A || dp->d_class != class)
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continue;
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/*
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* Don't use records that may become invalid to
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* reference later when we do the rtt computation.
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* Never delete our safety-belt information!
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*/
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if ((dp->d_zone == 0) &&
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(dp->d_ttl < (curtime+900)) &&
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!(dp->d_flags & DB_F_HINT) )
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{
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"nslookup: stale entry '%s'\n",
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np->n_dname);
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#endif
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/* Cache invalidate the NS RR's */
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if (dp->d_ttl < curtime)
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delete_all(np, class, T_A);
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n = oldn;
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break;
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}
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found_arr++;
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/* don't put in duplicates */
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qs = qp->q_addr;
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for (i = 0; i < n; i++, qs++)
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if (bcmp((char *)&qs->ns_addr.sin_addr,
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dp->d_data, sizeof(struct in_addr)) == 0)
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goto skipaddr;
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qs->ns_addr.sin_family = AF_INET;
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qs->ns_addr.sin_port = ns_port;
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qs->ns_addr.sin_addr =
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*(struct in_addr *)dp->d_data;
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qs->ns = nsdp;
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qs->nsdata = dp;
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qp->q_addr[n].nretry = 0;
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n++;
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if (n >= NSMAX)
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goto out;
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skipaddr: ;
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}
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"nslookup: %d ns addrs\n", n);
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#endif
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if (found_arr == 0 && qp->q_system == 0)
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(void) sysquery(dname, class, T_A);
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skipserver: ;
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}
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out:
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#ifdef DEBUG
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if (debug >= 3)
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fprintf(ddt,"nslookup: %d ns addrs total\n", n);
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#endif
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qp->q_naddr = n;
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if (n > 1)
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qsort((char *)qp->q_addr, n, sizeof(struct qserv), qcomp);
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return (n - naddr);
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}
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qcomp(qs1, qs2)
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struct qserv *qs1, *qs2;
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{
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return (qs1->nsdata->d_nstime - qs2->nsdata->d_nstime);
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}
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/*
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* Arrange that forwarded query (qp) is retried after t seconds.
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*/
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schedretry(qp, t)
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struct qinfo *qp;
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time_t t;
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{
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register struct qinfo *qp1, *qp2;
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#ifdef DEBUG
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if (debug > 3) {
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fprintf(ddt,"schedretry(%#x, %dsec)\n", qp, t);
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if (qp->q_time)
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fprintf(ddt,"WARNING: schedretry(%x,%d) q_time already %d\n", qp->q_time);
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}
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#endif
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t += (u_long) tt.tv_sec;
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qp->q_time = t;
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if ((qp1 = retryqp) == NULL) {
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retryqp = qp;
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qp->q_next = NULL;
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return;
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}
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if (t < qp1->q_time) {
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qp->q_next = qp1;
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retryqp = qp;
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return;
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}
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while ((qp2 = qp1->q_next) != NULL && qp2->q_time < t)
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qp1 = qp2;
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qp1->q_next = qp;
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qp->q_next = qp2;
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}
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/*
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* Unsched is called to remove a forwarded query entry.
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*/
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unsched(qp)
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struct qinfo *qp;
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{
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register struct qinfo *np;
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#ifdef DEBUG
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if (debug > 3) {
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fprintf(ddt,"unsched(%#x, %d )\n", qp, ntohs(qp->q_id));
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}
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#endif
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if( retryqp == qp ) {
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retryqp = qp->q_next;
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} else {
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for( np=retryqp; np->q_next != QINFO_NULL; np = np->q_next ) {
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if( np->q_next != qp)
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continue;
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np->q_next = qp->q_next; /* dequeue */
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break;
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}
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}
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qp->q_next = QINFO_NULL; /* sanity check */
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qp->q_time = 0;
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}
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/*
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* Retry is called to retransmit query 'qp'.
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*/
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retry(qp)
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register struct qinfo *qp;
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{
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register int n;
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register HEADER *hp;
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#ifdef DEBUG
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if (debug > 3)
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fprintf(ddt,"retry(x%x) id=%d\n", qp, ntohs(qp->q_id));
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#endif
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if((HEADER *)qp->q_msg == NULL) { /*** XXX ***/
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qremove(qp);
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return;
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} /*** XXX ***/
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/* try next address */
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n = qp->q_curaddr;
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if (qp->q_fwd) {
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qp->q_fwd = qp->q_fwd->next;
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if (qp->q_fwd)
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goto found;
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/* out of forwarders, try direct queries */
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} else
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++qp->q_addr[n].nretry;
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if (!forward_only) {
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do {
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if (++n >= qp->q_naddr)
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n = 0;
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if (qp->q_addr[n].nretry < MAXRETRY)
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goto found;
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} while (n != qp->q_curaddr);
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}
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/*
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* Give up. Can't reach destination.
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*/
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hp = (HEADER *)(qp->q_cmsg ? qp->q_cmsg : qp->q_msg);
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if (qp->q_system == PRIMING_CACHE) {
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/* Can't give up priming */
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unsched(qp);
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schedretry(qp, (time_t)60*60); /* 1 hour */
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hp->rcode = NOERROR; /* Lets be safe, reset the query */
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hp->qr = hp->aa = 0;
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qp->q_fwd = fwdtab;
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for (n = 0; n < qp->q_naddr; n++)
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qp->q_addr[n].nretry = 0;
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return;
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}
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#ifdef DEBUG
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if (debug >= 5)
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fprintf(ddt,"give up\n");
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#endif
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n = ((HEADER *)qp->q_cmsg ? qp->q_cmsglen : qp->q_msglen);
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hp->id = qp->q_id;
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hp->qr = 1;
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hp->ra = 1;
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hp->rd = 1;
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hp->rcode = SERVFAIL;
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#ifdef DEBUG
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if (debug >= 10)
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fp_query(qp->q_msg, ddt);
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#endif
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if (send_msg((char *)hp, n, qp)) {
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#ifdef DEBUG
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if (debug)
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fprintf(ddt,"gave up retry(x%x) nsid=%d id=%d\n",
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qp, ntohs(qp->q_nsid), ntohs(qp->q_id));
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#endif
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}
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qremove(qp);
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return;
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found:
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if (qp->q_fwd == 0 && qp->q_addr[n].nretry == 0)
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qp->q_addr[n].stime = tt;
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qp->q_curaddr = n;
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hp = (HEADER *)qp->q_msg;
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hp->rd = (qp->q_fwd ? 1 : 0);
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#ifdef DEBUG
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if (debug)
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fprintf(ddt,"%s(addr=%d n=%d) -> %s %d (%d) nsid=%d id=%d %dms\n",
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(qp->q_fwd ? "reforw" : "resend"),
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n, qp->q_addr[n].nretry,
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inet_ntoa(Q_NEXTADDR(qp,n)->sin_addr),
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ds, ntohs(Q_NEXTADDR(qp,n)->sin_port),
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ntohs(qp->q_nsid), ntohs(qp->q_id),
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qp->q_addr[n].nsdata->d_nstime);
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if ( debug >= 10)
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fp_query(qp->q_msg, ddt);
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#endif
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/* NOSTRICT */
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if (sendto(ds, qp->q_msg, qp->q_msglen, 0,
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(struct sockaddr *)Q_NEXTADDR(qp,n),
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sizeof(struct sockaddr_in)) < 0){
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#ifdef DEBUG
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if (debug > 3)
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fprintf(ddt,"error resending msg errno=%d\n",errno);
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#endif
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}
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hp->rd = 1; /* leave set to 1 for dup detection */
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#ifdef STATS
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stats[S_OUTPKTS].cnt++;
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#endif
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unsched(qp);
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schedretry(qp, qp->q_fwd ? (2*RETRYBASE) : retrytime(qp));
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}
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/*
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* Compute retry time for the next server for a query.
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* Use a minimum time of RETRYBASE (4 sec.) or twice the estimated
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* service time; * back off exponentially on retries, but place a 45-sec.
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* ceiling on retry times for now. (This is because we don't hold a reference
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* on servers or their addresses, and we have to finish before they time out.)
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*/
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time_t
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retrytime(qp)
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register struct qinfo *qp;
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{
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time_t t;
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struct qserv *ns = &qp->q_addr[qp->q_curaddr];
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#ifdef DEBUG
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if (debug > 3)
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fprintf(ddt,"retrytime: nstime %dms.\n",
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ns->nsdata->d_nstime / 1000);
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#endif
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t = (time_t) MAX(RETRYBASE, 2 * ns->nsdata->d_nstime / 1000);
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t <<= ns->nretry;
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t = MIN(t, 45); /* max. retry timeout for now */
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#ifdef notdef
|
|
if (qp->q_system)
|
|
return ((2 * t) + 5); /* system queries can wait. */
|
|
#endif
|
|
return (t);
|
|
}
|
|
|
|
qflush()
|
|
{
|
|
while (qhead)
|
|
qremove(qhead);
|
|
qhead = QINFO_NULL;
|
|
}
|
|
|
|
qremove(qp)
|
|
register struct qinfo *qp;
|
|
{
|
|
#ifdef DEBUG
|
|
if(debug > 3)
|
|
fprintf(ddt,"qremove(x%x)\n", qp);
|
|
#endif
|
|
unsched(qp); /* get off queue first */
|
|
qfree(qp);
|
|
}
|
|
|
|
struct qinfo *
|
|
qfindid(id)
|
|
register u_short id;
|
|
{
|
|
register struct qinfo *qp;
|
|
|
|
#ifdef DEBUG
|
|
if(debug > 3)
|
|
fprintf(ddt,"qfindid(%d)\n", ntohs(id));
|
|
#endif
|
|
for (qp = qhead; qp!=QINFO_NULL; qp = qp->q_link) {
|
|
if (qp->q_nsid == id)
|
|
return(qp);
|
|
}
|
|
#ifdef DEBUG
|
|
if (debug >= 5)
|
|
fprintf(ddt,"qp not found\n");
|
|
#endif
|
|
return(NULL);
|
|
}
|
|
|
|
struct qinfo *
|
|
qnew()
|
|
{
|
|
register struct qinfo *qp;
|
|
|
|
if ((qp = (struct qinfo *)calloc(1, sizeof(struct qinfo))) == NULL) {
|
|
#ifdef DEBUG
|
|
if (debug >= 5)
|
|
fprintf(ddt,"qnew: calloc error\n");
|
|
#endif
|
|
syslog(LOG_ERR, "forw: %m");
|
|
exit(12);
|
|
}
|
|
#ifdef DEBUG
|
|
if (debug >= 5)
|
|
fprintf(ddt,"qnew(x%x)\n", qp);
|
|
#endif
|
|
qp->q_link = qhead;
|
|
qhead = qp;
|
|
return( qp );
|
|
}
|
|
|
|
qfree(qp)
|
|
struct qinfo *qp;
|
|
{
|
|
register struct qinfo *np;
|
|
|
|
#ifdef DEBUG
|
|
if(debug > 3)
|
|
fprintf(ddt,"qfree( x%x )\n", qp);
|
|
if(debug && qp->q_next)
|
|
fprintf(ddt,"WARNING: qfree of linked ptr x%x\n", qp);
|
|
#endif
|
|
if (qp->q_msg)
|
|
free(qp->q_msg);
|
|
if (qp->q_cmsg)
|
|
free(qp->q_cmsg);
|
|
if( qhead == qp ) {
|
|
qhead = qp->q_link;
|
|
} else {
|
|
for( np=qhead; np->q_link != QINFO_NULL; np = np->q_link ) {
|
|
if( np->q_link != qp ) continue;
|
|
np->q_link = qp->q_link; /* dequeue */
|
|
break;
|
|
}
|
|
}
|
|
(void)free((char *)qp);
|
|
}
|