ns_req.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 1,919 行 · 第 1/3 页

		case FW_NOSERVER:
			if(np)
				np = np->n_parent;

			if(findns_count > 50) {
				needreload = 1;
#ifdef DEBUG
				if (debug)
				    fprintf(ddt,"ns_req:TOO many findns calls.\n");
#endif
				syslog(LOG_ERR, "ns_req:TOO many findns calls.  Auto HUP begins.");

				return;
			}

			goto fetchns;	/* Try again. */
		case FW_SERVFAIL:
			hp->rcode = SERVFAIL;
			goto finish;
		}

		/* Now is a safe time for housekeeping */
		if (needs_prime_cache)
			prime_cache();
		return;

	case IQUERY: {
		register struct invbuf *ip;
		register int i;
		int dlen, alen;
/* PACKETSZ below was changed to BUFSIZ.  This could affect transfers through
   gateways.  Fix the problem with TCP and malloc.  */
		char anbuf[BUFSIZ], *data;

#ifdef STATS
		stats[S_IQUERIES].cnt++;
#endif
		hp->ancount = htons(hp->ancount);
		if (hp->ancount != 1 ||
		    hp->qdcount || hp->nscount || hp->arcount) {
#ifdef DEBUG
			if (debug)
			    fprintf(ddt,"FORMERR IQuery header counts wrong\n");
#endif
			hp->qdcount = 0;
			hp->ancount = 0;
			hp->nscount = 0;
			hp->arcount = 0;
			hp->rcode = FORMERR;
			goto finish;
		}
		/*
		 * Skip domain name, get class, and type.
		 */
		if ((n = dn_skipname(cp, eom)) < 0) {
#ifdef DEBUG
			if (debug)
			    fprintf(ddt,"FORMERR IQuery packet name problem\n");
#endif
			hp->rcode = FORMERR;
			goto finish;
		}
		cp += n;
		GETSHORT(type, cp);
		GETSHORT(class, cp);
		cp += sizeof(u_long);
		GETSHORT(dlen, cp);
		cp += dlen;
		if (cp != eom) {
#ifdef DEBUG
			if (debug)
			    fprintf(ddt,"FORMERR IQuery message length off\n");
#endif
			hp->rcode = FORMERR;
			goto finish;
		}
		/* not all inverse queries are handled. */
		switch (type) {
		case T_A:
		case T_UID:
		case T_GID:
			break;

		default:
			hp->rcode = REFUSED;
			goto finish;
		}
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"req: IQuery class %d type %d\n",
				class, type);
#endif
		fname = (char *)msg + sizeof(HEADER);
		bcopy(fname, anbuf, alen = (char *)cp - fname);
		data = anbuf + alen - dlen;
		cp = (u_char *)fname;
		buflen -= sizeof(HEADER);
		count = 0;
		for (ip = invtab[dhash(data, dlen)]; ip != NULL;
		    ip = ip->i_next) {
		    for (i = 0; i < INVBLKSZ; i++) {
			if ((np = ip->i_dname[i]) == NULL)
				break;
#ifdef DEBUG
			if (debug >= 5)
				fprintf(ddt,"dname = %d\n", np->n_dname);
#endif
			for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
				if (!match(dp, class, type))
					continue;
				if (dp->d_size != dlen ||
				    bcmp(dp->d_data, data, dlen))
					continue;
				getname(np, dnbuf, sizeof(dnbuf));
#ifdef DEBUG
				if (debug > 2)
					fprintf(ddt,"req: IQuery found %s\n",
						dnbuf);
#endif
				buflen -= QFIXEDSZ;
				if ((n =
				   dn_comp(dnbuf, cp, buflen, (char **)NULL,
				      (char **)NULL)) < 0)
				{
					hp->tc = 1;
					goto finish;
				}
				cp += n;
				PUTSHORT((u_short)dp->d_type, cp);
				PUTSHORT((u_short)dp->d_class, cp);
				buflen -= n;
				count++;
			}
		    }
		}
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"req: IQuery %d records\n", count);
#endif
		hp->qdcount = htons((u_short)count);
		if (alen > buflen) {
			hp->tc = 1;
			break;
		}
		bcopy(anbuf, cp, alen);
		cp += alen;
		break;
	    }

#ifdef ALLOW_UPDATES
/*
 * In a sense the following constant should be defined in <arpa/nameser.h>,
 * since it is returned here in place of a response code if the update was
 * forwarded, and the response codes are defined in nameser.h.  On the other
 * hand, though, this constant is only seen in this file.  The assumption
 * here is that none of the other return codes equals this one (a good
 * assumption, since they only occupy 4 bits over-the-wire)
 */
#define FORWARDED 1000
        /* Call InitDynUpdate for all dynamic update requests */
        case UPDATEM:
        case UPDATEMA:
        case UPDATED:
        case UPDATEDA:
        case UPDATEA:
                n = InitDynUpdate(hp, nsp, msg, msglen, cp, from, qsp, dfd);
                if (n == FORWARDED)
                        return; /* Return directly because InitDynUpdate
                                 * forwarded the query to the primary, so we
                                 * will send response later
                                 */
                else
                        break;  /* Either sucessful primary update or failure;
                                 * return response code to client
                                 */
#endif ALLOW_UPDATES

	case ZONEREF:
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"Refresh Zone\n");
#endif

	default:
#ifdef DEBUG
		if (debug >= 2)
			fprintf(ddt,"Opcode %d not implemented\n", hp->opcode);
#endif
		hp->qdcount = 0;
		hp->ancount = 0;
		hp->nscount = 0;
		hp->arcount = 0;
		hp->rcode = NOTIMP;
	}
finish:
#ifdef STATS
	switch(hp->rcode) {
	case NOERROR:
		stats[S_RESPOK].cnt++;
		break;
	case FORMERR:
		stats[S_RESPFORMERR].cnt++;
		break;
	default:
		stats[S_RESPFAIL].cnt++;
		break;
	}
#endif
	hp->qr = 1;		/* set Response flag */
	hp->ra = 1;		/* Recursion is Available */
	hp->ancount = htons(hp->ancount);

#ifdef AUTHEN
	if(netsafe && query_to_aquery) {
		if(fixup_rrs(ocp, (int)(cp - ocp), (int)(ocp - (u_char *)hp),
				-(2 * sizeof(u_short)))	< 0)
			return(-1);
		ocp2 = ocp;
		ocp -= 2 * sizeof(u_short);
		bcopy(ocp2, ocp, cp - ocp2);
		hp->opcode = QUERY;
		query_to_aquery = 0;
		cp -= 2 * sizeof(u_short);
	}
#endif AUTHEN

	if (addcount) {

#ifdef AUTHEN
		if(hp->opcode == AQUERY)
			n = doaddinfo(hp, cp, DEFSIZE_KRBCRED);
		else

			n = doaddinfo(hp, cp, buflen);
#else
		n = doaddinfo(hp, cp, buflen);
#endif AUTHEN
		cp += n;
		buflen -= n;
	}
	
#ifdef AUTHEN
	if(hp->opcode == AQUERY && read_cred) {
		/* switch on auth type */
		dnptr = dname_authenrr;
		if(type_authenrr != T_SOA && type_authenrr != T_AXFR)
			res_dotname_rmhead(&dnptr);
		hp->arcount = htons(1 + ntohs(hp->arcount));
		if((cred_len = res_mks_krbcred(auth_version,
					       "", "", &ns_ad,
					       hp, cp, buflen,
					       dnptr,
					       type_authenrr,
					       class_authenrr))
		   < RET_OK) {
			hp->rcode = AUTHENBAD;
			cp = ocp;
			hp->ancount = 0;
			hp->nscount = 0;
			hp->arcount = 0;

		} else {
			cp += cred_len;
		}
	}
#endif AUTHEN
		
	
#ifdef DEBUG
	if (debug) {
	    fprintf(ddt,"req: answer -> %s %d (%d) id=%d %s\n",
	        inet_ntoa(from->sin_addr), dfd, ntohs(from->sin_port),
		ntohs(hp->id), local(from) == NULL ? "Remote" : "Local");
	}
	if (debug >= 10)
		fp_query(msg, ddt);
#endif DEBUG
	if (qsp == QSTREAM_NULL) {
		if (sendto(dfd, msg, cp-msg, 0, (struct sockaddr *)from,
		    sizeof(*from))< 0){
#ifdef DEBUG
			if (debug)
			    fprintf(ddt,"error returning msg errno=%d\n",errno);
#endif DEBUG
		}
#ifdef STATS
		stats[S_OUTPKTS].cnt++;
#endif
	} else {
		(void) writemsg(qsp->s_rfd, msg, cp - msg);
		qsp->s_time = tt.tv_sec;
		qsp->s_refcnt--;
	}
	if (needs_prime_cache)
		prime_cache();	/* Now is a safe time */
}

fwritemsg(rfp, msg, msglen)
	FILE *rfp;
	char *msg;
	int msglen;
{
	u_short len = htons((u_short)msglen);

	if (fwrite((char *)&len, sizeof(len), 1, rfp) != 1 ||
	    fwrite(msg, msglen, 1, rfp) != 1) {
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"fwrite failed %d\n", errno);
#endif
	}
	return;
}

writemsg(rfd, msg, msglen)
	int rfd;
	char *msg;
	int msglen;
{
	struct iovec iov[2];
	u_short len = htons((u_short)msglen);

	iov[0].iov_base = (caddr_t)&len;
	iov[0].iov_len = sizeof(len);
	iov[1].iov_base = msg;
	iov[1].iov_len = msglen;
	if (writev(rfd, iov, 2) != sizeof(len) + msglen) {
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"write failed %d\n", errno);
#endif
		return (-1);
	}
	return (0);
}

/*
 *  Test a datum for validity and return non-zero if it is out of date.
 */
stale(dp)
register struct databuf *dp;
{
	register struct zoneinfo *zp = &zones[dp->d_zone];

	switch (zp->z_type) {

	case Z_PRIMARY:
		return (0);

	case Z_SECONDARY:
		return ((u_long)(tt.tv_sec - zp->z_lastupdate) > zp->z_expire);

	case Z_CACHE:
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"stale: ttl %d %d (x%x)\n",
				dp->d_ttl, dp->d_ttl - tt.tv_sec, dp->d_flags);
#endif
		if (dp->d_flags & DB_F_HINT)
			return(0);
		return(dp->d_ttl < tt.tv_sec);

	}
	/* NOTREACHED */
}

/*
 * Copy databuf into a resource record for replies.
 * Return size of RR if OK, -1 if buffer is full.
 */
make_rr(name, dp, buf, buflen, doadd)
	char *name;
	register struct databuf *dp;
	char *buf;
	int buflen, doadd;
{
	register char *cp;
	char *cp1, *sp;
	struct zoneinfo *zp;
	register long n;
	register long ttl;
	u_char **edp = dnptrs + sizeof(dnptrs)/sizeof(dnptrs[0]);

#ifdef DEBUG
	if (debug >= 5)
		fprintf(ddt,"make_rr(%s, %x, %x, %d, %d) %d zone %d ttl %d\n",
			name, dp, buf,
			buflen, doadd, dp->d_size, dp->d_zone, dp->d_ttl);
#endif

	zp = &zones[dp->d_zone];
	/* check for outdated RR before updating dnptrs by dn_comp() */
	if (zp->z_type == Z_CACHE) {
		ttl = dp->d_ttl - (u_long) tt.tv_sec;
		if ((dp->d_flags & DB_F_HINT) || (ttl <= 0)) {
#ifdef DEBUG
/*XXX*/if (debug >= 3) fprintf(ddt,"make_rr: %d=>1, x%x\n", ttl, dp->d_flags);
#endif
			ttl = 1;
		}
	} else {
		ttl = zp->z_minimum;		/* really default */
		if (dp->d_ttl > 0)
			ttl = dp->d_ttl;
		if (zp->z_type == Z_SECONDARY) {
			/*
			 * Set ttl to value received from primary,
			 * less time since we verified it (but never
			 * less than a small positive value).
			 */
			ttl -= tt.tv_sec - zp->z_lastupdate;
			if (ttl <= 0)
				ttl = 120;
		}
	}

	buflen -= RRFIXEDSZ;
	if ((n = dn_comp(name, buf, buflen, (char **)dnptrs, (char **)edp)) < 0)
		return (-1);
	cp = buf + n;
	buflen -= n;
	PUTSHORT((u_short)dp->d_type, cp);
	PUTSHORT((u_short)dp->d_class, cp);
	PUTLONG(ttl, cp);
	sp = cp;
	cp += sizeof(u_short);
	switch (dp->d_type) {
	case T_CNAME:
	case T_MG:
	case T_MR:
	case T_PTR:
		if ((n = dn_comp(dp->d_data, cp, buflen, (char **)dnptrs,
		   (char **)edp)) < 0)
			return (-1);
		PUTSHORT((u_short)n, sp);
		cp += n;
		break;

	case T_MB:
	case T_NS:
		/* Store domain name in answer */
		if ((n = dn_comp(dp->d_data, cp, buflen, (char **)dnptrs,
		   (char **)edp)) < 0)
			return (-1);
		PUTSHORT((u_short)n, sp);
		cp += n;
		if (doadd)
			addname(dp->d_data, dp->d_class);
		break;

	case T_SOA:
	case T_MINFO:
		cp1 = dp->d_data;
		if ((n = dn_comp(cp1, cp, buflen, (char **)dnptrs,
		    (char **)edp)) < 0)
			return (-1);
		cp += n;
		buflen -= dp->d_type == T_MINFO ? n : n + 5 * sizeof(u_long);
		cp1 += strlen(cp1) + 1;
		if ((n = dn_comp(cp1, cp, buflen, (char **)dnptrs,
		    (char **)edp)) < 0)
			return (-1);
		cp += n;
		if (dp->d_type == T_SOA) {
			cp1 += strlen(cp1) + 1;
			bcopy(cp1, cp,
			   (int)(n = dp->d_size - (cp1 - dp->d_data)));
			cp += n;
		}
		n = (u_short)(cp - sp) - sizeof(u_short);
		PUTSHORT((u_short)n, sp);
		break;

	case T_MX:
		/* cp1 == our data/ cp == data of RR */
		cp1 = dp->d_data;

 		/* copy preference */
 		bcopy(cp1,cp,sizeof(u_short));
 		cp += sizeof(u_short);
 		cp1 += sizeof(u_short);
 		buflen -= sizeof(u_short);

  		if ((n = dn_comp(cp1, cp, buflen, (char **)dnptrs,
		    (char **)edp)) < 0)
  			return(-1);
  		cp += n;

  		/* save data length */
  		n = (u_short)(cp - sp) - sizeof(u_short);
  		PUTSHORT((u_short)n, sp);
		if (doadd)
			addname(cp1, dp->d_class);
		break;

	default:
		if (dp->d_size > buflen)
			return (-1);
		bcopy(dp->d_data, cp, dp->d_size);
		PUTSHORT((u_short)dp->d_size, sp);
		cp += dp->d_size;
	}
	return (cp - buf);
}

addname(name, class)
register char	*name;
short	class;
{
	register struct addinfo *ap;
	register int n;

	for (ap = addinfo, n = addcount; --n >= 0; ap++)
		if (strcasecmp(ap->a_dname, name) == 0)
			return;
	/* add domain name to additional section */
	if (addcount < NADDRECS) {
		addcount++;
		ap->a_dname = name;
		ap->a_class = class;
	}
}

/*
 * Lookup addresses for names in addinfo and put into the message's
 * additional section.
 */
doaddinfo(hp, msg, msglen)
	HEADER *hp;
	char *msg;
	int msglen;
{
	register struct namebuf *np;
	register struct databuf *dp;
	register struct addinfo *ap;
	register char *cp;
	struct hashbuf *htp;
	char *fname;
	int n, count, foundstale;

#ifdef DEBUG
	if (debug >= 3)
		fprintf(ddt,"doaddinfo() addcount = %d\n", addcount);
#endif

	count = 0;
	cp = msg;
	for (ap = addinfo; --addcount >= 0; ap++) {
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"do additional '%s'\n", ap->a_dname);
#endif
		htp = hashtab;	/* because "nlookup" stomps on arg. */
		np = nlookup(ap->a_dname, &htp, &fname, 0);
		if (np == NULL || fname != ap->a_dname)
			continue;
#ifdef DEBUG
		if (debug >= 3)
			fprintf(ddt,"found it\n");
#endif
		foundstale = 0;
		/* look for the data */
		for (dp = np->n_data; dp != NULL; dp = dp->d_next) {
			if (!match(dp, (int)ap->a_class, T_A))
				continue;
			if (stale(dp)) {
				foundstale++;
#ifdef DEBUG
				if (debug)
				    fprintf(ddt,"doaddinfo: stale entry '%s'%s\n",
					    np->n_dname,
					    (dp->d_flags&DB_F_HINT) ? " hint":"" );
#endif
				continue;
			}
			/*
			 *  Should be smart and eliminate duplicate
			 *  data here.	XXX
			 */
			if ((n = make_rr(ap->a_dname, dp, cp, msglen, 0)) < 0)
				break;
#ifdef DEBUG
			if (debug >= 5)
			    fprintf(ddt,"addinfo: adding address data n = %d\n",
			       n);
#endif
			cp += n;
			msglen -= n;
			count++;
		}
		if (foundstale) {
			/* Cache invalidate the address RR's */
			delete_all(np, (int)ap->a_class, T_A);
			(void) sysquery(ap->a_dname, (int)ap->a_class, T_A);
		}
	}
	hp->arcount = htons((u_short)count);
	return (cp - msg);
}

doaddauth(hp, cp, buflen, np, dp)
	register HEADER *hp;
	char *cp;
	int buflen;
	struct namebuf *np;
	struct databuf *dp;
{
	char dnbuf[MAXDNAME];
	int n;

	getname(np, dnbuf, sizeof(dnbuf));
	if (stale(dp) || (n = make_rr(dnbuf, dp, cp, buflen, 1)) <= 0) {
#ifdef DEBUG
		if (debug)
			fprintf(ddt,"doaddauth: can't add '%s' (%d)\n",
				dnbuf, buflen);
#endif
		return(0);
	} else {
		hp->nscount = htons(1);
		return(n);
	}
}

/*
 * Get the domain name of 'np' and put in 'buf'.  Bounds checking is done.
 */
getname(np, buf, buflen)
	struct namebuf *np;
	char *buf;
	int buflen;
{
	register char *cp;
	register int i;

	cp = buf;
	while (np != NULL) {
		if ((i = strlen(np->n_dname))+1 >= buflen) {
			*cp = '\0';
			syslog(LOG_ERR, "domain name too long: %s...\n", buf);