diff options
Diffstat (limited to 'contrib/bind/named/ns_forw.c')
| -rw-r--r-- | contrib/bind/named/ns_forw.c | 1094 |
1 files changed, 1094 insertions, 0 deletions
diff --git a/contrib/bind/named/ns_forw.c b/contrib/bind/named/ns_forw.c new file mode 100644 index 0000000..362bf8b --- /dev/null +++ b/contrib/bind/named/ns_forw.c @@ -0,0 +1,1094 @@ +#if !defined(lint) && !defined(SABER) +static char sccsid[] = "@(#)ns_forw.c 4.32 (Berkeley) 3/3/91"; +static char rcsid[] = "$Id: ns_forw.c,v 8.14 1996/08/05 08:31:30 vixie Exp $"; +#endif /* not lint */ + +/* + * ++Copyright++ 1986 + * - + * Copyright (c) 1986 + * 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) 1993 by Digital Equipment Corporation. + * + * 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, and that + * the name of Digital Equipment Corporation not be used in advertising or + * publicity pertaining to distribution of the document or software without + * specific, written prior permission. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL + * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT + * CORPORATION 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. + * - + * --Copyright-- + */ + +#include <sys/types.h> +#include <sys/param.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <arpa/nameser.h> + +#include <syslog.h> +#include <resolv.h> +#include <stdio.h> +#include <errno.h> + +#include "named.h" + +/* + * 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 or if asked to do something + * dangerous, such as fwd to ourselves or fwd to the host that asked us. + * + * (no action is taken on errors and qpp is not filled in.) + */ +int +ns_forw(nsp, msg, msglen, fp, qsp, dfd, qpp, dname, np) + struct databuf *nsp[]; + u_char *msg; + int msglen; + struct sockaddr_in *fp; + struct qstream *qsp; + int dfd; + struct qinfo **qpp; + char *dname; + struct namebuf *np; +{ + register struct qinfo *qp; + struct sockaddr_in *nsa; + HEADER *hp; + u_int16_t id; + int n; + + dprintf(3, (ddt, "ns_forw()\n")); + + hp = (HEADER *) msg; + id = hp->id; + /* Look at them all */ + for (qp = nsqhead; 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))) { + dprintf(3, (ddt, + "forw: dropped DUP id=%d\n", ntohs(id))); +#ifdef XSTATS + nameserIncr(fp->sin_addr, nssRcvdDupQ); +#endif + return (FW_DUP); + } + } + + qp = qnew(); +#if defined(LAME_DELEGATION) || defined(VALIDATE) + getname(np, qp->q_domain, sizeof qp->q_domain); +#endif + qp->q_from = *fp; /* nslookup wants to know this */ + if ((n = nslookup(nsp, qp, dname, "ns_forw")) < 0) { + dprintf(2, (ddt, "forw: nslookup reports danger\n")); + qfree(qp); + return (FW_SERVFAIL); + } else if (n == 0 && !fwdtab) { + dprintf(2, (ddt, "forw: no nameservers found\n")); + qfree(qp); + return (FW_NOSERVER); + } + qp->q_stream = qsp; + qp->q_curaddr = 0; + qp->q_fwd = fwdtab; + qp->q_dfd = dfd; + qp->q_id = id; + qp->q_expire = tt.tv_sec + RETRY_TIMEOUT*2; + hp->id = qp->q_nsid = htons(nsid_next()); + hp->ancount = htons(0); + hp->nscount = htons(0); + hp->arcount = htons(0); + if ((qp->q_msg = (u_char *)malloc((unsigned)msglen)) == NULL) { + syslog(LOG_NOTICE, "forw: malloc: %m"); + qfree(qp); + return (FW_SERVFAIL); + } + bcopy(msg, qp->q_msg, qp->q_msglen = msglen); + if (!qp->q_fwd) { + hp->rd = 0; + qp->q_addr[0].stime = tt; + } + +#ifdef SLAVE_FORWARD + if (forward_only) + schedretry(qp, (time_t)slave_retry); + else +#endif /* SLAVE_FORWARD */ + schedretry(qp, qp->q_fwd ?(2*RETRYBASE) :retrytime(qp)); + + nsa = Q_NEXTADDR(qp, 0); + dprintf(1, (ddt, + "forw: forw -> [%s].%d ds=%d nsid=%d id=%d %dms retry %dsec\n", + inet_ntoa(nsa->sin_addr), + ntohs(nsa->sin_port), ds, + ntohs(qp->q_nsid), ntohs(qp->q_id), + (qp->q_addr[0].nsdata != NULL) + ? qp->q_addr[0].nsdata->d_nstime + : -1, + (int)(qp->q_time - tt.tv_sec))); +#ifdef DEBUG + if (debug >= 10) + fp_nquery(msg, msglen, ddt); +#endif + if (sendto(ds, (char *)msg, msglen, 0, (struct sockaddr *)nsa, + sizeof(struct sockaddr_in)) < 0) { + if (!haveComplained((char*)nsa->sin_addr.s_addr, sendtoStr)) + syslog(LOG_INFO, "ns_forw: sendto([%s].%d): %m", + inet_ntoa(nsa->sin_addr), ntohs(nsa->sin_port)); + nameserIncr(nsa->sin_addr, nssSendtoErr); + } +#ifdef XSTATS + nameserIncr(fp->sin_addr, nssRcvdFwdQ); +#endif + nameserIncr(nsa->sin_addr, nssSentFwdQ); + if (qpp) + *qpp = qp; + hp->rd = 1; + return (0); +} + +/* struct qdatagram * + * aIsUs(addr) + * scan the datagramq (our list of interface addresses) for "addr" + * returns: + * pointer to qdatagram entry or NULL if no match is found + * notes: + * INADDR_ANY ([0.0.0.0]) is on the datagramq, so it's considered "us" + * author: + * Paul Vixie (DECWRL) April 1991 + */ +struct qdatagram * +aIsUs(addr) + struct in_addr addr; +{ + struct qdatagram *dqp; + + for (dqp = datagramq; dqp != QDATAGRAM_NULL; dqp = dqp->dq_next) { + if (addr.s_addr == dqp->dq_addr.s_addr) { + return dqp; + } + } + return NULL; +} + +/* haveComplained(tag1, tag2) + * check to see if we have complained about (tag1,tag2) recently + * (note that these are declared as pointers but are never deref'd) + * returns: + * boolean: have we complained recently? + * side-effects: + * outdated complaint records removed from our static list + * author: + * Paul Vixie (DECWRL) April 1991 + */ +int +haveComplained(tag1, tag2) + const char *tag1, *tag2; +{ + struct complaint { + const char *tag1, *tag2; + time_t expire; + struct complaint *next; + }; + static struct complaint *List = NULL; + struct complaint *cur, *next, *prev; + int r = 0; + + for (cur = List, prev = NULL; cur; prev = cur, cur = next) { + next = cur->next; + if (tt.tv_sec > cur->expire) { + if (prev) + prev->next = next; + else + List = next; + free((char*) cur); + cur = prev; + } else if ((tag1 == cur->tag1) && (tag2 == cur->tag2)) { + r++; + } + } + if (!r) { + cur = (struct complaint *)malloc(sizeof(struct complaint)); + if (cur) { + cur->tag1 = tag1; + cur->tag2 = tag2; + cur->expire = tt.tv_sec + INIT_REFRESH; /* "10:00" */ + cur->next = NULL; + if (prev) + prev->next = cur; + else + List = cur; + } + } + return (r); +} + +/* void + * nslookupComplain(sysloginfo, queryname, complaint, dname, a_rr) + * Issue a complaint about a dangerous situation found by nslookup(). + * params: + * sysloginfo is a string identifying the complainant. + * queryname is the domain name associated with the problem. + * complaint is a string describing what is wrong. + * dname and a_rr are the problematic other name server. + */ +static void +nslookupComplain(sysloginfo, queryname, complaint, dname, a_rr, nsdp) + const char *sysloginfo, *queryname, *complaint, *dname; + const struct databuf *a_rr, *nsdp; +{ +#ifdef STATS + char nsbuf[20]; + char abuf[20]; +#endif + char *a, *ns; + const char *a_type; + int print_a; + + dprintf(2, (ddt, "NS '%s' %s\n", dname, complaint)); + if (sysloginfo && queryname && !haveComplained(queryname, complaint)) + { + char buf[999]; + + a = ns = (char *)NULL; + print_a = (a_rr->d_type == T_A); + a_type = p_type(a_rr->d_type); +#ifdef NCACHE + if (a_rr->d_rcode) { + print_a = 0; + switch(a_rr->d_rcode) { + case NXDOMAIN: + a_type = "NXDOMAIN"; + break; + case NOERROR_NODATA: + a_type = "NODATA"; + break; + } + } +#endif +#ifdef STATS + if (nsdp) { + if (nsdp->d_ns) { + strcpy(nsbuf, inet_ntoa(nsdp->d_ns->addr)); + ns = nsbuf; + } else { + ns = zones[nsdp->d_zone].z_origin; + } + } + if (a_rr->d_ns) { + strcpy(abuf, inet_ntoa(a_rr->d_ns->addr)); + a = abuf; + } else { + a = zones[a_rr->d_zone].z_origin; + } +#endif + /* syslog only takes 5 params */ + if ( a != NULL || ns != NULL) + sprintf(buf, "%s: query(%s) %s (%s:%s) learnt (%s=%s:NS=%s)", + sysloginfo, queryname, + complaint, dname, + print_a ? + inet_ntoa(data_inaddr(a_rr->d_data)) : "", + a_type, + a ? a : "<Not Available>", + ns ? ns : "<Not Available>" ); + else + sprintf(buf, "%s: query(%s) %s (%s:%s)", + sysloginfo, queryname, + complaint, dname, + print_a ? + inet_ntoa(data_inaddr(a_rr->d_data)) : ""); + syslog(LOG_INFO, buf); + } +} + +/* + * nslookup(nsp, qp, syslogdname, sysloginfo) + * Lookup the address for each nameserver in `nsp' and add it to + * the list saved in the qinfo structure pointed to by `qp'. + * Omits information about nameservers that we shouldn't ask. + * Detects the following dangerous operations: + * One of the A records for one of the nameservers in nsp + * refers to the address of one of our own interfaces; + * One of the A records refers to the nameserver port on + * the host that asked us this question. + * returns: the number of addresses added, or -1 if a dangerous operation + * is detected. + * side effects: + * if a dangerous situation is detected and (syslogdname && sysloginfo), + * calls syslog. + */ +int +nslookup(nsp, qp, syslogdname, sysloginfo) + struct databuf *nsp[]; + register struct qinfo *qp; + const char *syslogdname; + const char *sysloginfo; +{ + register struct namebuf *np; + register struct databuf *dp, *nsdp; + register struct qserv *qs; + register int n; + register unsigned int i; + struct hashbuf *tmphtp; + char *dname; + const char *fname; + int oldn, naddr, class, found_arr, potential_ns; + time_t curtime; + + dprintf(3, (ddt, "nslookup(nsp=0x%lx, qp=0x%lx, \"%s\")\n", + (u_long)nsp, (u_long)qp, syslogdname)); + + potential_ns = 0; + naddr = n = qp->q_naddr; + curtime = (u_long) tt.tv_sec; + while ((nsdp = *nsp++) != NULL) { + class = nsdp->d_class; + dname = (char *)nsdp->d_data; + dprintf(3, (ddt, "nslookup: NS \"%s\" c=%d t=%d (%#lx)\n", + dname, class, nsdp->d_type, + (u_long)nsdp->d_flags)); + + /* don't put in servers we have tried */ + for (i = 0; i < qp->q_nusedns; i++) { + if (qp->q_usedns[i] == nsdp) { + dprintf(2, (ddt, + "skipping used NS w/name %s\n", + nsdp->d_data)); + goto skipserver; + } + } + + tmphtp = ((nsdp->d_flags & DB_F_HINT) ?fcachetab :hashtab); + np = nlookup(dname, &tmphtp, &fname, 1); + if (np == NULL) { + dprintf(3, (ddt, "%s: not found %s %lx\n", + dname, fname, (u_long)np)); + found_arr = 0; + goto need_sysquery; + } + if (fname != dname) { + if (findMyZone(np, class) == DB_Z_CACHE) { + /* + * lifted from findMyZone() + * We really need to know if the NS + * is the bottom of one of our zones + * to see if we've got missing glue + */ + for (; np; np = np_parent(np)) + for (dp = np->n_data; dp; dp=dp->d_next) + if (match(dp, class, T_NS)) { +#ifdef NCACHE + if (dp->d_rcode) + break; +#endif + if (dp->d_zone) { + static char *complaint = + "Glue A RR missing"; + nslookupComplain(sysloginfo, + syslogdname, + complaint, + dname, dp, + nsdp); + goto skipserver; + } else { + found_arr = 0; + goto need_sysquery; + } + } + /* shouldn't happen, but ... */ + found_arr = 0; + goto need_sysquery; + } else { + static char *complaint = + "Authoritative A RR missing"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } + } + found_arr = 0; + oldn = n; + + /* look for name server addresses */ + for (dp = np->n_data; dp != NULL; dp = dp->d_next) { + struct in_addr nsa; + + if (dp->d_type == T_CNAME && dp->d_class == class) { + static char *complaint = "NS points to CNAME"; +#ifdef NCACHE + if (dp->d_rcode) + continue; +#endif + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + goto skipserver; + } + if (dp->d_type != T_A || dp->d_class != class) + continue; +#ifdef NCACHE + if (dp->d_rcode) { + static char *complaint = + "A RR negative cache entry"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + goto skipserver; + } +#endif + if (data_inaddr(dp->d_data).s_addr == INADDR_ANY) { + static char *complaint = "Bogus (0.0.0.0) A RR"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } +#ifdef INADDR_LOOPBACK + if (ntohl(data_inaddr(dp->d_data).s_addr) == + INADDR_LOOPBACK) { + static char *complaint = "Bogus LOOPBACK A RR"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } +#endif +#ifdef INADDR_BROADCAST + if (ntohl(data_inaddr(dp->d_data).s_addr) == + INADDR_BROADCAST) { + static char *complaint = "Bogus BROADCAST A RR"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } +#endif +#ifdef IN_MULTICAST + if (IN_MULTICAST(ntohl(data_inaddr(dp->d_data).s_addr))) { + static char *complaint = "Bogus MULTICAST A RR"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } +#endif + /* + * 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) && +#ifdef DATUMREFCNT + (dp->d_ttl < curtime) && +#else + (dp->d_ttl < (curtime+900)) && +#endif + !(dp->d_flags & DB_F_HINT) ) + { + dprintf(3, (ddt, + "nslookup: stale entry '%s'\n", + NAME(*np))); + /* Cache invalidate the NS RR's */ +#ifndef DATUMREFCNT + if (dp->d_ttl < curtime) +#endif + { + delete_all(np, class, T_A); + n = oldn; + found_arr = 0; + goto need_sysquery; + } + } +#ifdef VALIDATE + /* anant@isi.edu validation procedure, maintains a + * table of server names-addresses used recently + */ + store_name_addr(dname, data_inaddr(dp->d_data), + syslogdname, sysloginfo); +#endif /*VALIDATE*/ + + found_arr++; + nsa = data_inaddr(dp->d_data); + /* don't put in duplicates */ + qs = qp->q_addr; + for (i = 0; i < n; i++, qs++) + if (qs->ns_addr.sin_addr.s_addr == nsa.s_addr) + goto skipaddr; + qs->ns_addr.sin_family = AF_INET; + qs->ns_addr.sin_port = ns_port; + qs->ns_addr.sin_addr = nsa; + qs->ns = nsdp; + qs->nsdata = dp; + qs->nretry = 0; + /* + * if we are being asked to fwd a query whose + * nameserver list includes our own name/address(es), + * then we have detected a lame delegation and rather + * than melt down the network and hose down the other + * servers (who will hose us in return), we'll return + * -1 here which will cause SERVFAIL to be sent to + * the client's resolver which will hopefully then + * shut up. + * + * (originally done in nsContainsUs by vix@dec mar92; + * moved into nslookup by apb@und jan1993) + * + * try to limp along instead of denying service + * gdonl mar96 + */ + if (aIsUs(nsa)) { + static char *complaint = "contains our address"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } + /* + * If we want to forward to a host that asked us + * this question then either we or they are sick + * (unless they asked from some port other than + * their nameserver port). (apb@und jan1993) + * + * try to limp along instead of denying service + * gdonl mar96 + */ + if (bcmp((char *)&qp->q_from, (char *)&qs->ns_addr, + sizeof(qp->q_from)) == 0) + { + static char *complaint = "forwarding loop"; + nslookupComplain(sysloginfo, syslogdname, + complaint, dname, dp, nsdp); + continue; + } +#ifdef BOGUSNS + /* + * Don't forward queries to bogus servers. Note + * that this is unlike the previous tests, which + * are fatal to the query. Here we just skip the + * server, which is only fatal if it's the last + * server. Note also that we antialias here -- all + * A RR's of a server are considered the same server, + * and if any of them is bogus we skip the whole + * server. Those of you using multiple A RR's to + * load-balance your servers will (rightfully) lose + * here. But (unfortunately) only if they are bogus. + */ + if (addr_on_netlist(nsa, boglist)) + goto skipserver; +#endif + + n++; + if (n >= NSMAX) + goto out; + skipaddr: + NULL; + } + dprintf(8, (ddt, "nslookup: %d ns addrs\n", n)); + need_sysquery: + if (found_arr == 0) { + potential_ns++; + if (!(qp->q_flags & Q_SYSTEM)) + (void) sysquery(dname, class, T_A, NULL, 0, + QUERY); + } + skipserver: + NULL; + } +out: + dprintf(3, (ddt, "nslookup: %d ns addrs total\n", n)); + qp->q_naddr = n; + if (n == 0 && potential_ns == 0 && !fwdtab) { + static char *complaint = "No possible A RRs"; + if (sysloginfo && syslogdname && + !haveComplained(syslogdname, complaint)) + { + syslog(LOG_INFO, "%s: query(%s) %s", + sysloginfo, syslogdname, complaint); + } + return(-1); + } +#ifdef DATUMREFCNT + /* must be run before the sort */ + for (i = naddr ; i < n ; i++) { + qp->q_addr[i].nsdata->d_rcnt++; + qp->q_addr[i].ns->d_rcnt++; + } +#endif + if (n > 1) { + qsort((char *)qp->q_addr, n, sizeof(struct qserv), + (int (*)__P((const void *, const void *)))qcomp); + } + return (n - naddr); +} + +/* + * qcomp - compare two NS addresses, and return a negative, zero, or + * positive value depending on whether the first NS address is + * "better than", "equally good as", or "inferior to" the second + * NS address. + * + * How "goodness" is defined (for the purposes of this routine): + * - If the estimated round trip times differ by an amount deemed significant + * then the one with the smaller estimate is preferred; else + * - If we can determine which one is topologically closer then the + * closer one is preferred; else + * - The one with the smaller estimated round trip time is preferred + * (zero is returned if the two estimates are identical). + * + * How "topological closeness" is defined (for the purposes of this routine): + * Ideally, named could consult some magic map of the Internet and + * determine the length of the path to an arbitrary destination. Sadly, + * no such magic map exists. However, named does have a little bit of + * topological information in the form of the sortlist (which includes + * the directly connected subnet(s), the directly connected net(s), and + * any additional nets that the administrator has added using the "sortlist" + * directive in the bootfile. Thus, if only one of the addresses matches + * something in the sortlist then it is considered to be topologically + * closer. If both match, but match different entries in the sortlist, + * then the one that matches the entry closer to the beginning of the + * sorlist is considered to be topologically closer. In all other cases, + * topological closeness is ignored because it's either indeterminate or + * equal. + * + * How times are compared: + * Both times are rounded to the closest multiple of the NOISE constant + * defined below and then compared. If the rounded values are equal + * then the difference in the times is deemed insignificant. Rounding + * is used instead of merely taking the absolute value of the difference + * because doing the latter would make the ordering defined by this + * routine be incomplete in the mathematical sense (e.g. A > B and + * B > C would not imply A > C). The mathematics are important in + * practice to avoid core dumps in qsort(). + * + * XXX: this doesn't solve the European root nameserver problem very well. + * XXX: we should detect and mark as inferior nameservers that give bogus + * answers + * + * (this was originally vixie's stuff but almquist fixed fatal bugs in it + * and wrote the above documentation) + */ + +/* + * RTT delta deemed to be significant, in milliseconds. With the current + * definition of RTTROUND it must be a power of 2. + */ +#define NOISE 128 /* milliseconds; 0.128 seconds */ + +#define sign(x) (((x) < 0) ? -1 : ((x) > 0) ? 1 : 0) +#define RTTROUND(rtt) (((rtt) + (NOISE >> 1)) & ~(NOISE - 1)) + +int +qcomp(qs1, qs2) + struct qserv *qs1, *qs2; +{ + int pos1, pos2, pdiff; + u_long rtt1, rtt2; + long tdiff; + + if ((!qs1->nsdata) || (!qs2->nsdata)) + return 0; + rtt1 = qs1->nsdata->d_nstime; + rtt2 = qs2->nsdata->d_nstime; + + dprintf(10, (ddt, "qcomp(%s, %s) %lu (%lu) - %lu (%lu) = %lu", + inet_ntoa(qs1->ns_addr.sin_addr), + inet_ntoa(qs2->ns_addr.sin_addr), + rtt1, RTTROUND(rtt1), rtt2, RTTROUND(rtt2), + rtt1 - rtt2)); + if (RTTROUND(rtt1) == RTTROUND(rtt2)) { + pos1 = position_on_netlist(qs1->ns_addr.sin_addr, nettab); + pos2 = position_on_netlist(qs2->ns_addr.sin_addr, nettab); + pdiff = pos1 - pos2; + dprintf(10, (ddt, ", pos1=%d, pos2=%d\n", pos1, pos2)); + if (pdiff) + return (pdiff); + } else { + dprintf(10, (ddt, "\n")); + } + tdiff = rtt1 - rtt2; + return (sign(tdiff)); +} +#undef sign +#undef RTTROUND + +/* + * Arrange that forwarded query (qp) is retried after t seconds. + * Query list will be sorted after z_time is updated. + */ +void +schedretry(qp, t) + struct qinfo *qp; + time_t t; +{ + register struct qinfo *qp1, *qp2; + +#ifdef DEBUG + if (debug > 3) { + fprintf(ddt, "schedretry(0x%lx, %ld sec)\n", + (u_long)qp, (long)t); + if (qp->q_time) + fprintf(ddt, + "WARNING: schedretry(%#lx, %ld) q_time already %ld\n", + (u_long)qp, (long)t, (long)qp->q_time); + } +#endif + t += (u_long) tt.tv_sec; + qp->q_time = t; + + if ((qp1 = retryqp) == NULL) { + retryqp = qp; + qp->q_next = NULL; + return; + } + if (t < qp1->q_time) { + qp->q_next = qp1; + retryqp = qp; + return; + } + while ((qp2 = qp1->q_next) != NULL && qp2->q_time < t) + qp1 = qp2; + qp1->q_next = qp; + qp->q_next = qp2; +} + +/* + * Unsched is called to remove a forwarded query entry. + */ +void +unsched(qp) + struct qinfo *qp; +{ + register struct qinfo *np; + + dprintf(3, (ddt, "unsched(%#lx, %d)\n", (u_long)qp, ntohs(qp->q_id))); + if (retryqp == qp) { + retryqp = qp->q_next; + } else { + for (np=retryqp; np->q_next != QINFO_NULL; np = np->q_next) { + if (np->q_next != qp) + continue; + np->q_next = qp->q_next; /* dequeue */ + break; + } + } + qp->q_next = QINFO_NULL; /* sanity check */ + qp->q_time = 0; +} + +/* + * Retry is called to retransmit query 'qp'. + */ +void +retry(qp) + register struct qinfo *qp; +{ + register int n; + register HEADER *hp; + struct sockaddr_in *nsa; + + dprintf(3, (ddt, "retry(x%lx) id=%d\n", (u_long)qp, ntohs(qp->q_id))); + + if (qp->q_msg == NULL) { /* XXX - why? */ + qremove(qp); + return; + } + + if (qp->q_expire && (qp->q_expire < tt.tv_sec)) { + dprintf(1, (ddt, + "retry(x%lx): expired @ %lu (%d secs before now (%lu))\n", + (u_long)qp, (u_long)qp->q_expire, + (int)(tt.tv_sec - qp->q_expire), + (u_long)tt.tv_sec)); + if (qp->q_stream) /* return failure code on stream */ + goto fail; + qremove(qp); + return; + } + + /* try next address */ + n = qp->q_curaddr; + if (qp->q_fwd) { + qp->q_fwd = qp->q_fwd->next; + if (qp->q_fwd) + goto found; + /* out of forwarders, try direct queries */ + } else + ++qp->q_addr[n].nretry; + if (!forward_only) { + do { + if (++n >= (int)qp->q_naddr) + n = 0; + if (qp->q_addr[n].nretry < MAXRETRY) + goto found; + } while (n != qp->q_curaddr); + } +fail: + /* + * Give up. Can't reach destination. + */ + hp = (HEADER *)(qp->q_cmsg ? qp->q_cmsg : qp->q_msg); + if (qp->q_flags & Q_PRIMING) { + /* Can't give up priming */ + unsched(qp); + schedretry(qp, (time_t)60*60); /* 1 hour */ + hp->rcode = NOERROR; /* Lets be safe, reset the query */ + hp->qr = hp->aa = 0; + qp->q_fwd = fwdtab; + for (n = 0; n < (int)qp->q_naddr; n++) + qp->q_addr[n].nretry = 0; + return; + } + dprintf(5, (ddt, "give up\n")); + n = ((HEADER *)qp->q_cmsg ? qp->q_cmsglen : qp->q_msglen); + hp->id = qp->q_id; + hp->qr = 1; + hp->ra = (NoRecurse == 0); + hp->rd = 1; + hp->rcode = SERVFAIL; +#ifdef DEBUG + if (debug >= 10) + fp_nquery(qp->q_msg, n, ddt); +#endif + if (send_msg((u_char *)hp, n, qp)) { + dprintf(1, (ddt, "gave up retry(x%lx) nsid=%d id=%d\n", + (u_long)qp, ntohs(qp->q_nsid), ntohs(qp->q_id))); + } +#ifdef XSTATS + nameserIncr(qp->q_from.sin_addr, nssSentFail); +#endif + qremove(qp); + return; + +found: + if (qp->q_fwd == 0 && qp->q_addr[n].nretry == 0) + qp->q_addr[n].stime = tt; + qp->q_curaddr = n; + hp = (HEADER *)qp->q_msg; + hp->rd = (qp->q_fwd ? 1 : 0); + nsa = Q_NEXTADDR(qp, n); + dprintf(1, (ddt, + "%s(addr=%d n=%d) -> [%s].%d ds=%d nsid=%d id=%d %dms\n", + (qp->q_fwd ? "reforw" : "resend"), + n, qp->q_addr[n].nretry, + inet_ntoa(nsa->sin_addr), + ntohs(nsa->sin_port), ds, + ntohs(qp->q_nsid), ntohs(qp->q_id), + (qp->q_addr[n].nsdata != 0) + ? qp->q_addr[n].nsdata->d_nstime + : (-1))); +#ifdef DEBUG + if (debug >= 10) + fp_nquery(qp->q_msg, qp->q_msglen, ddt); +#endif + /* NOSTRICT */ + if (sendto(ds, (char*)qp->q_msg, qp->q_msglen, 0, + (struct sockaddr *)nsa, + sizeof(struct sockaddr_in)) < 0) { + dprintf(3, (ddt, "error resending msg errno=%d\n", errno)); + } + hp->rd = 1; /* leave set to 1 for dup detection */ + nameserIncr(nsa->sin_addr, nssSentDupQ); + unsched(qp); +#ifdef SLAVE_FORWARD + if(forward_only) + schedretry(qp, (time_t)slave_retry); + else +#endif /* SLAVE_FORWARD */ + schedretry(qp, qp->q_fwd ? (2*RETRYBASE) : retrytime(qp)); +} + +/* + * Compute retry time for the next server for a query. + * Use a minimum time of RETRYBASE (4 sec.) or twice the estimated + * service time; * back off exponentially on retries, but place a 45-sec. + * ceiling on retry times for now. (This is because we don't hold a reference + * on servers or their addresses, and we have to finish before they time out.) + */ +time_t +retrytime(qp) + struct qinfo *qp; +{ + time_t t, u, v; + struct qserv *ns = &qp->q_addr[qp->q_curaddr]; + + if (ns->nsdata != NULL) + t = (time_t) MAX(RETRYBASE, 2 * ns->nsdata->d_nstime / 1000); + else + t = (time_t) RETRYBASE; + u = t << ns->nretry; + v = MIN(u, RETRY_TIMEOUT); /* max. retry timeout for now */ + dprintf(3, (ddt, "retrytime: nstime%ldms t%ld nretry%ld u%ld : v%ld\n", + ns->nsdata ?(long)(ns->nsdata->d_nstime / 1000) :(long)-1, + (long)t, (long)ns->nretry, (long)u, (long)v)); + return (v); +} + +void +qflush() +{ + while (nsqhead) + qremove(nsqhead); + nsqhead = QINFO_NULL; +} + +void +qremove(qp) + register struct qinfo *qp; +{ + dprintf(3, (ddt, "qremove(x%lx)\n", (u_long)qp)); + + if (qp->q_flags & Q_ZSERIAL) + qserial_answer(qp, 0); + unsched(qp); + qfree(qp); +} + +#if defined(__STDC__) || defined(__GNUC__) +struct qinfo * +qfindid(u_int16_t id) +#else +struct qinfo * +qfindid(id) + register u_int16_t id; +#endif +{ + register struct qinfo *qp; + + dprintf(3, (ddt, "qfindid(%d)\n", ntohs(id))); + for (qp = nsqhead; qp!=QINFO_NULL; qp = qp->q_link) { + if (qp->q_nsid == id) + return(qp); + } + dprintf(5, (ddt, "qp not found\n")); + return (NULL); +} + +struct qinfo * +#ifdef DMALLOC +qnew_tagged(file, line) + char *file; + int line; +#else +qnew() +#endif +{ + register struct qinfo *qp; + + qp = (struct qinfo *) +#ifdef DMALLOC + dcalloc(file, line, 1, sizeof(struct qinfo)); +#else + calloc(1, sizeof(struct qinfo)); +#endif + if (qp == NULL) { + dprintf(5, (ddt, "qnew: calloc error\n")); + syslog(LOG_ERR, "forw: %m"); + exit(12); + } + dprintf(5, (ddt, "qnew(x%lx)\n", (u_long)qp)); +#ifdef BIND_NOTIFY + qp->q_notifyzone = DB_Z_CACHE; +#endif + qp->q_link = nsqhead; + nsqhead = qp; + return (qp); +} + +void +qfree(qp) + struct qinfo *qp; +{ + register struct qinfo *np; + register struct databuf *dp; +#ifdef DATUMREFCNT + int i; +#endif + + dprintf(3, (ddt, "Qfree(x%lx)\n", (u_long)qp)); + if (qp->q_next) + dprintf(1, (ddt, "WARNING: qfree of linked ptr x%lx\n", + (u_long)qp)); + if (qp->q_msg) + free(qp->q_msg); + if (qp->q_cmsg) + free(qp->q_cmsg); +#ifdef DATUMREFCNT + for (i = 0 ; i < (int)qp->q_naddr ; i++) { + dp = qp->q_addr[i].ns; + if (dp) + if (--(dp->d_rcnt)) { + dprintf(3, (ddt, "qfree: ns %s rcnt %d\n", + dp->d_data, + dp->d_rcnt)); + } else { + dprintf(3, (ddt, "qfree: ns %s rcnt %d delayed\n", + dp->d_data, + dp->d_rcnt)); + free((char*)dp); + } + dp = qp->q_addr[i].nsdata; + if (dp) + if ((--(dp->d_rcnt))) { + dprintf(3, (ddt, "qfree: nsdata %08.8X rcnt %d\n", + *(int32_t *)(dp->d_data), + dp->d_rcnt)); + } else { + dprintf(3, (ddt, "qfree: nsdata %08.8X rcnt %d delayed\n", + *(int32_t *)(dp->d_data), + dp->d_rcnt)); + free((char*)dp); + } + } +#endif + if( nsqhead == qp ) { + nsqhead = qp->q_link; + } else { + for( np=nsqhead; np->q_link != QINFO_NULL; np = np->q_link ) { + if( np->q_link != qp ) continue; + np->q_link = qp->q_link; /* dequeue */ + break; + } + } + free((char *)qp); +} |
