Answerr= -1,
Answnone,
- Maxdest= 24, /* maximum destinations for a request message */
+ Maxdest= 32, /* maximum destinations for a request message */
Maxoutstanding= 15, /* max. outstanding queries per domain name */
- Remntretry= 15, /* min. sec.s between /net.alt remount tries */
/*
* these are the old values; we're trying longer timeouts now
* primarily for the benefit of remote nameservers querying us
* during times of bad connectivity.
*/
-// Maxtrans= 3, /* maximum transmissions to a server */
-// Maxretries= 3, /* cname+actual resends: was 32; have pity on user */
-// Maxwaitms= 1000, /* wait no longer for a remote dns query */
-// Minwaitms= 100, /* willing to wait for a remote dns query */
-
Maxtrans= 5, /* maximum transmissions to a server */
- Maxretries= 5, /* cname+actual resends: was 32; have pity on user */
- Maxwaitms= 5000, /* wait no longer for a remote dns query */
- Minwaitms= 500, /* willing to wait for a remote dns query */
+ Maxretries= 10, /* cname+actual resends: was 32; have pity on user */
};
enum { Hurry, Patient, };
enum { Outns, Inns, };
struct Dest
{
uchar a[IPaddrlen]; /* ip address */
- DN *s; /* name server */
+ DN *s; /* name server name */
+ RR *n; /* name server rr */
int nx; /* number of transmissions */
int code; /* response code; used to clear dp->respcode */
};
DN *dp; /* domain */
ushort type; /* and type to look up */
Request *req;
+ Query *prev; /* previous query */
+
RR *nsrp; /* name servers to consult */
- /* dest must not be on the stack due to forking in slave() */
Dest *dest; /* array of destinations */
Dest *curdest; /* pointer to next to fill */
int ndest; /* transmit to this many on this round */
uchar tcpip[IPaddrlen];
};
-/* estimated % probability of such a record existing at all */
-int likely[] = {
- [Ta] 95,
- [Taaaa] 10,
- [Tcname] 15,
- [Tmx] 60,
- [Tns] 90,
- [Tnull] 5,
- [Tptr] 35,
- [Tsoa] 90,
- [Tsrv] 60,
- [Ttxt] 15,
- [Tall] 95,
-};
-
static RR* dnresolve1(char*, int, int, Request*, int, int);
static int netquery(Query *, int);
* try the name directly
*/
rp = dnresolve1(name, class, type, req, depth, recurse);
- if(rp == nil && (dp = dnlookup(name, class, 0)) != nil) {
+ if(rp == nil && (dp = idnlookup(name, class, 0)) != nil) {
/*
* try it as a canonical name if we weren't told
* that the name didn't exist
qp->type = type;
if (qp->type != type)
dnslog("queryinit: bogus type %d", type);
- qp->req = req;
qp->nsrp = nil;
qp->dest = qp->curdest = nil;
+ qp->prev = req->aux;
+ qp->req = req;
+ req->aux = qp;
}
static void
querydestroy(Query *qp)
{
+ if(qp->req->aux == qp)
+ qp->req->aux = qp->prev;
/* leave udpfd open */
if (qp->tcpfd >= 0)
close(qp->tcpfd);
{
int rv;
+ if(nsrp == nil)
+ return Answnone;
qp->nsrp = nsrp;
rv = netquery(qp, depth);
qp->nsrp = nil; /* prevent accidents */
}
/* look for ns in cache */
- nsdp = dnlookup(cp, class, 0);
+ nsdp = idnlookup(cp, class, 0);
nsrp = nil;
if(nsdp)
nsrp = randomize(rrlookup(nsdp, Tns, NOneg));
if(class != Cin)
return nil;
- dp = dnlookup(name, class, 1);
+ dp = idnlookup(name, class, 1);
/*
* Try the cache first
return 0;
}
+static int
+queryloops(Query *qp, RR *rp)
+{
+ DN *ns = rp->host;
+
+ /*
+ * looking up a server under itself
+ */
+ if(subsume(rp->owner->name, ns->name))
+ return 1;
+
+ /*
+ * cycle on name servers refering
+ * to each another.
+ */
+ for(; qp; qp = qp->prev)
+ if(qp->dp == ns)
+ return 1;
+
+ return 0;
+}
+
/*
- * Get next server address(es) into qp->dest[nd] and beyond
+ * Get next server type address(es) into qp->dest[nd] and beyond
*/
static int
-serveraddrs(Query *qp, int nd, int depth)
+serveraddrs(Query *qp, int nd, int depth, int type)
{
RR *rp, *arp, *trp;
+ ulong mark;
Dest *p;
if(nd >= Maxdest) /* dest array is full? */
* if we find one, mark it so we ignore this on
* subsequent passes.
*/
- arp = 0;
+ mark = 1UL<<type;
+ arp = nil;
for(rp = qp->nsrp; rp; rp = rp->next){
assert(rp->magic == RRmagic);
- if(rp->marker)
+ if(rp->marker & mark)
continue;
- arp = rrlookup(rp->host, Ta, NOneg);
- if(arp == nil)
- arp = rrlookup(rp->host, Taaaa, NOneg);
+ arp = rrlookup(rp->host, type, NOneg);
if(arp){
- rp->marker = 1;
+ rp->marker |= mark;
break;
}
- arp = dblookup(rp->host->name, Cin, Ta, 0, 0);
- if(arp == nil)
- arp = dblookup(rp->host->name, Cin, Taaaa, 0, 0);
+ arp = dblookup(rp->host->name, Cin, type, 0, 0);
if(arp){
- rp->marker = 1;
+ rp->marker |= mark;
break;
}
}
* server addresses, try resolving one via the network.
* Mark any we try to resolve so we don't try a second time.
*/
- if(arp == 0)
- for(rp = qp->nsrp; rp; rp = rp->next){
- if(rp->marker)
- continue;
- rp->marker = 1;
+ if(arp == nil){
+ for(rp = qp->nsrp; rp; rp = rp->next)
+ if((rp->marker & mark) == 0)
+ if(queryloops(qp, rp))
+ /*
+ * give up as we should have got the address
+ * by higher up nameserver when recursing
+ * down, or will be queried when recursing up.
+ */
+ return nd;
- /*
- * avoid loops looking up a server under itself
- */
- if(subsume(rp->owner->name, rp->host->name))
+ for(rp = qp->nsrp; rp; rp = rp->next){
+ if(rp->marker & mark)
continue;
-
- arp = dnresolve(rp->host->name, Cin, Ta, qp->req, 0,
+ rp->marker |= mark;
+ arp = dnresolve(rp->host->name, Cin, type, qp->req, 0,
depth+1, Recurse, 1, 0);
- if(arp == nil)
- arp = dnresolve(rp->host->name, Cin, Taaaa,
- qp->req, 0, depth+1, Recurse, 1, 0);
rrfreelist(rrremneg(&arp));
if(arp)
break;
}
+ }
/* use any addresses that we found */
for(trp = arp; trp && nd < Maxdest; trp = trp->next){
p = &qp->dest[nd];
memset(p, 0, sizeof *p);
- parseip(p->a, trp->ip->name);
+ if(parseip(p->a, trp->ip->name) == -1)
+ continue;
+
/*
* straddling servers can reject all nameservers if they are all
* inside, so be sure to list at least one outside ns at
cfg.straddle && !insideaddr(qp->dp->name) && insidens(p->a))
continue;
p->nx = 0;
+ p->n = nil;
p->s = trp->owner;
+ for(rp = qp->nsrp; rp; rp = rp->next){
+ if(rp->host == p->s){
+ p->n = rp;
+ break;
+ }
+ }
p->code = Rtimeout;
nd++;
}
mydnsquery(Query *qp, int medium, uchar *udppkt, int len)
{
int rv, nfd;
- char conndir[40], addr[128], domain[64];
+ char conndir[40], addr[128];
uchar belen[2];
NetConnInfo *nci;
rv = -1;
- snprint(domain, sizeof(domain), "%I", udppkt);
- if (myaddr(domain))
+ if (myip(udppkt))
return rv;
switch (medium) {
case Udp:
case Tcp:
/* send via TCP & keep fd around for reply */
memmove(qp->tcpip, udppkt, sizeof qp->tcpip);
- snprint(addr, sizeof addr, "%s/tcp!%s!dns",
- (mntpt && *mntpt) ? mntpt : "/net",
- domain);
+ snprint(addr, sizeof addr, "%s/tcp!%I!dns",
+ (mntpt && *mntpt) ? mntpt : "/net", udppkt);
alarm(10*1000);
qp->tcpfd = dial(addr, nil, conndir, &qp->tcpctlfd);
alarm(0);
p = qp->dest;
n = qp->curdest - p;
if (qp->ndest > n) {
- n = serveraddrs(qp, n, depth); /* populates qp->dest. */
- assert(n >= 0 && n <= Maxdest);
+ /* populates qp->dest with v4 and v6 addresses. */
+ n = serveraddrs(qp, n, depth, Ta);
+ n = serveraddrs(qp, n, depth, Taaaa);
if (n == 0 && cfg.straddle && cfg.inside) {
/* get ips of "outside-ns-ips" */
while(n < Maxdest){
if((1<<p->nx) > qp->ndest)
continue;
- if(memcmp(p->a, IPnoaddr, sizeof IPnoaddr) == 0)
+ if(ipcmp(p->a, IPnoaddr) == 0)
continue; /* mistake */
procsetname("udp %sside query to %I/%s %s %s",
return mp->an == nil && (mp->flags & Rmask) == Rname;
}
+static int
+filterhints(RR *rp, void *arg)
+{
+ RR *nsrp;
+
+ if(rp->type != Ta && rp->type != Taaaa)
+ return 0;
+
+ for(nsrp = arg; nsrp; nsrp = nsrp->next)
+ if(nsrp->type == Tns && rp->owner == nsrp->host)
+ return 1;
+
+ return 0;
+}
+
+static int
+filterauth(RR *rp, void *arg)
+{
+ Dest *dest;
+ RR *nsrp;
+
+ dest = arg;
+ nsrp = dest->n;
+ if(nsrp == nil)
+ return 0;
+
+ if(rp->type == Tsoa && rp->owner != nsrp->owner
+ && !subsume(nsrp->owner->name, rp->owner->name)
+ && strncmp(nsrp->owner->name, "local#", 6) != 0)
+ return 1;
+
+ if(rp->type != Tns)
+ return 0;
+
+ if(rp->owner != nsrp->owner
+ && !subsume(nsrp->owner->name, rp->owner->name)
+ && strncmp(nsrp->owner->name, "local#", 6) != 0)
+ return 1;
+
+ return baddelegation(rp, nsrp, dest->a);
+}
+
+static void
+reportandfree(RR *l, char *note, Dest *p)
+{
+ RR *rp;
+
+ while(rp = l){
+ l = l->next;
+ rp->next = nil;
+ if(debug)
+ dnslog("ignoring %s from %I/%s: %R",
+ note, p->a, p->s->name, rp);
+ rrfree(rp);
+ }
+}
+
/* returns Answerr (-1) on errors, else number of answers, which can be zero. */
static int
-procansw(Query *qp, DNSmsg *mp, uchar *srcip, int depth, Dest *p)
+procansw(Query *qp, DNSmsg *mp, int depth, Dest *p)
{
int rv;
char buf[32];
Query nq;
RR *tp, *soarr;
- if (mp->an == nil)
+ if(mp->an == nil)
stats.negans++;
/* ignore any error replies */
- if((mp->flags & Rmask) == Rserver){
+ switch(mp->flags & Rmask){
+ case Rrefused:
+ case Rserver:
stats.negserver++;
freeanswers(mp);
- if(p != nil)
- p->code = Rserver;
+ p->code = Rserver;
return Answerr;
}
/* ignore any bad delegations */
- if(mp->ns && baddelegation(mp->ns, qp->nsrp, srcip)){
- stats.negbaddeleg++;
- if(mp->an == nil){
- stats.negbdnoans++;
- freeanswers(mp);
- if(p != nil)
- p->code = Rserver;
- dnslog(" and no answers");
- return Answerr;
- }
- dnslog(" but has answers; ignoring ns");
- rrfreelistptr(&mp->ns);
- mp->nscount = 0;
- }
+ if((tp = rrremfilter(&mp->ns, filterauth, p)) != 0)
+ reportandfree(tp, "bad delegation", p);
/* remove any soa's from the authority section */
soarr = rrremtype(&mp->ns, Tsoa);
+ /* only nameservers remaining */
+ if((tp = rrremtype(&mp->ns, Tns)) != 0){
+ reportandfree(mp->ns, "non-nameserver", p);
+ mp->ns = tp;
+ }
+
+ /* remove answers not related to the question. */
+ if((tp = rrremowner(&mp->an, qp->dp)) != 0){
+ reportandfree(mp->an, "wrong subject answer", p);
+ mp->an = tp;
+ }
+ if(qp->type != Tall){
+ if((tp = rrremtype(&mp->an, qp->type)) != 0){
+ reportandfree(mp->an, "wrong type answer", p);
+ mp->an = tp;
+ }
+ }
+
/* incorporate answers */
unique(mp->an);
unique(mp->ns);
if(mp->an){
/*
* only use cname answer when returned. some dns servers
- * attach (potential) spam hint address records which poisons the cache.
+ * attach (potential) spam hint address records which poisons
+ * the cache.
*/
if((tp = rrremtype(&mp->an, Tcname)) != 0){
- if(mp->an)
- rrfreelist(mp->an);
+ reportandfree(mp->an, "ip in cname answer", p);
mp->an = tp;
}
rrattach(mp->an, (mp->flags & Fauth) != 0);
}
- if(mp->ar)
+ if(mp->ar){
+ /* restrict hints to address rr's for nameservers only */
+ if((tp = rrremfilter(&mp->ar, filterhints, mp->ns)) != 0){
+ reportandfree(mp->ar, "hint", p);
+ mp->ar = tp;
+ }
rrattach(mp->ar, Notauthoritative);
+ }
if(mp->ns && !cfg.justforw){
ndp = mp->ns->owner;
rrattach(mp->ns, Notauthoritative);
}
/*
- * Any reply from an authoritative server,
+ * Any reply from an authoritative server
+ * that does not provide more nameservers,
* or a positive reply terminates the search.
* A negative response now also terminates the search.
*/
- if(mp->an != nil || (mp->flags & Fauth)){
+ if(mp->an || (mp->flags & Fauth) && mp->ns == nil){
if(isnegrname(mp))
qp->dp->respcode = Rname;
else
* if we're a pure resolver, don't recurse, we have
* to forward to a fixed set of named servers.
*/
- if(!mp->ns || cfg.resolver && cfg.justforw)
+ if(mp->ns == nil || cfg.resolver && cfg.justforw)
return Answnone;
tp = rrlookup(ndp, Tns, NOneg);
if(contains(qp->nsrp, tp)){
static int
queryns(Query *qp, int depth, uchar *ibuf, uchar *obuf, ulong waitms, int inns)
{
- int ndest, len, replywaits, rv;
+ int ndest, len, replywaits, rv, flag;
ushort req;
uvlong endms;
char buf[32];
uchar srcip[IPaddrlen];
Dest *p, *np, dest[Maxdest];
- /* pack request into a udp message */
req = rand();
- len = mkreq(qp->dp, qp->type, obuf, Frecurse|Oquery, req);
+
+ /* request recursion only for local dns servers */
+ flag = Oquery;
+ if(strncmp(qp->nsrp->owner->name, "local#", 6) == 0)
+ flag |= Frecurse;
+
+ /* pack request into a udp message */
+ len = mkreq(qp->dp, qp->type, obuf, flag, req);
/* no server addresses yet */
memset(dest, 0, sizeof dest);
* each cycle send one more message than the previous.
* retry a query via tcp if its response is truncated.
*/
- for(ndest = 1; ndest < Maxdest; ndest++){
+ for(ndest = 2; ndest < Maxdest; ndest += 2){
qp->ndest = ndest;
qp->tcpset = 0;
if (xmitquery(qp, Udp, depth, obuf, inns, len) < 0)
}
/* find responder */
- // dnslog("queryns got reply from %I", srcip);
+ if(debug)
+ dnslog("queryns got reply from %I", srcip);
for(p = qp->dest; p < qp->curdest; p++)
- if(memcmp(p->a, srcip, sizeof p->a) == 0)
+ if(ipcmp(p->a, srcip) == 0)
break;
+ if(p >= qp->curdest){
+ dnslog("response from %I but no destination", srcip);
+ continue;
+ }
- if(p != qp->curdest) {
- /* remove all addrs of responding server from list */
- for(np = qp->dest; np < qp->curdest; np++)
- if(np->s == p->s)
- np->nx = Maxtrans;
- } else
- p = nil;
+ /* remove all addrs of responding server from list */
+ for(np = qp->dest; np < qp->curdest; np++)
+ if(np->s == p->s)
+ np->nx = Maxtrans;
/* free or incorporate RRs in m */
- rv = procansw(qp, &m, srcip, depth, p);
+ rv = procansw(qp, &m, depth, p);
if (rv > Answnone) {
qp->dest = qp->curdest = nil; /* prevent accidents */
return rv;
return Answnone;
}
-/*
- * run a command with a supplied fd as standard input
- */
-char *
-system(int fd, char *cmd)
-{
- int pid, p, i;
- static Waitmsg msg;
-
- if((pid = fork()) == -1)
- sysfatal("fork failed: %r");
- else if(pid == 0){
- dup(fd, 0);
- close(fd);
- for (i = 3; i < 200; i++)
- close(i); /* don't leak fds */
- execl("/bin/rc", "rc", "-c", cmd, nil);
- sysfatal("exec rc: %r");
- }
- for(p = waitpid(); p >= 0; p = waitpid())
- if(p == pid)
- return msg.msg;
- return "lost child";
-}
-
-/* compute wait, weighted by probability of success, with bounds */
-static ulong
-weight(ulong ms, unsigned pcntprob)
-{
- ulong wait;
-
- wait = (ms * pcntprob) / 100;
- if (wait < Minwaitms)
- wait = Minwaitms;
- if (wait > Maxwaitms)
- wait = Maxwaitms;
- return wait;
-}
-
/*
* in principle we could use a single descriptor for a udp port
* to send all queries and receive all the answers to them,
udpquery(Query *qp, char *mntpt, int depth, int patient, int inns)
{
int fd, rv;
- long now;
- ulong pcntprob;
- uvlong wait, reqtm;
- char *msg;
uchar *obuf, *ibuf;
- static QLock mntlck;
- static ulong lastmount;
-
- rv = -1;
/* use alloced buffers rather than ones from the stack */
ibuf = emalloc(64*1024); /* max. tcp reply size */
obuf = emalloc(Maxudp+Udphdrsize);
fd = udpport(mntpt);
- while (fd < 0 && cfg.straddle && strcmp(mntpt, "/net.alt") == 0) {
- /* HACK: remount /net.alt */
- now = time(nil);
- if (now < lastmount + Remntretry)
- sleep(S2MS(lastmount + Remntretry - now));
- qlock(&mntlck);
- fd = udpport(mntpt); /* try again under lock */
- if (fd < 0) {
- dnslog("[%d] remounting /net.alt", getpid());
- unmount(nil, "/net.alt");
-
- msg = system(open("/dev/null", ORDWR), "outside");
-
- lastmount = time(nil);
- if (msg && *msg) {
- dnslog("[%d] can't remount /net.alt: %s",
- getpid(), msg);
- sleep(10*1000); /* don't spin remounting */
- } else
- fd = udpport(mntpt);
- }
- qunlock(&mntlck);
- }
if (fd < 0) {
dnslog("can't get udpport for %s query of name %s: %r",
mntpt, qp->dp->name);
+ rv = -1;
goto Out;
}
-
- /*
- * Our QIP servers are busted and respond to AAAA and CNAME queries
- * with (sometimes malformed [too short] packets and) no answers and
- * just NS RRs but not Rname errors. so make time-to-wait
- * proportional to estimated probability of an RR of that type existing.
- */
- if (qp->type >= nelem(likely))
- pcntprob = 35; /* unpopular query type */
- else
- pcntprob = likely[qp->type];
- reqtm = (patient? 2 * Maxreqtm: Maxreqtm);
- wait = weight(reqtm / 3, pcntprob); /* time for one udp query */
-
qp->udpfd = fd;
- rv = queryns(qp, depth, ibuf, obuf, wait, inns);
+ rv = queryns(qp, depth, ibuf, obuf, 500UL<<(patient != 0), inns);
qp->udpfd = -1;
close(fd);
req.aborttime = timems() + Maxreqtm;
req.from = "internal";
queryinit(&q, dnlookup(root, Cin, 1), Tns, &req);
- nsrp = dblookup(root, Cin, Tns, 0, 0);
+ nsrp = randomize(dblookup(root, Cin, Tns, 0, 0));
for (rr = nsrp; rr != nil; rr = rr->next)
dnslog("seerootns query nsrp: %R", rr);
rv = netqueryns(&q, 0, nsrp); /* lookup ". ns" using nsrp */
projects / plan9front.git / blobdiff