add dns

1 files changed, 1563 insertions, 0 deletions

diff --git a/src/cmd/ndb/dn.c b/src/cmd/ndb/dn.c
new file mode 100755
index 00000000..a38d4305
--- /dev/null
+++ b/src/cmd/ndb/dn.c
@@ -0,0 +1,1563 @@
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include <ctype.h>
+#include <bio.h>
+#include <ndb.h>
+#include "dns.h"
+
+/*
+ *  Hash table for domain names.  The hash is based only on the
+ *  first element of the domain name.
+ */
+DN	*ht[HTLEN];
+
+
+static struct
+{
+	Lock	lk;
+	ulong	names;	/* names allocated */
+	ulong	oldest;	/* longest we'll leave a name around */
+	int	active;
+	int	mutex;
+	int	id;
+} dnvars;
+
+/* names of RR types */
+char *rrtname[] =
+{
+[Ta]		"ip",
+[Tns]		"ns",
+[Tmd]		"md",
+[Tmf]		"mf",
+[Tcname]	"cname",
+[Tsoa]		"soa",
+[Tmb]		"mb",
+[Tmg]		"mg",
+[Tmr]		"mr",
+[Tnull]		"null",
+[Twks]		"wks",
+[Tptr]		"ptr",
+[Thinfo]	"hinfo",
+[Tminfo]	"minfo",
+[Tmx]		"mx",
+[Ttxt]		"txt",
+[Trp]		"rp",
+[Tkey]		"key",
+[Tcert]		"cert",
+[Tsig]		"sig",
+[Taaaa]		"ipv6",
+[Tixfr]		"ixfr",
+[Taxfr]		"axfr",
+[Tall]		"all",
+		0,
+};
+
+/* names of response codes */
+char *rname[Rmask+1] =
+{
+[Rok]			"ok",
+[Rformat]		"format error",
+[Rserver]		"server failure",
+[Rname]			"bad name",
+[Runimplimented]	"unimplemented",
+[Rrefused]		"we don't like you",
+};
+
+/* names of op codes */
+char *opname[] =
+{
+[Oquery]	"query",
+[Oinverse]	"inverse",
+[Ostatus]	"status",
+};
+
+Lock	dnlock;
+
+static int sencodefmt(Fmt*);
+
+/*
+ *  set up a pipe to use as a lock
+ */
+void
+dninit(void)
+{
+	fmtinstall('E', eipfmt);
+	fmtinstall('I', eipfmt);
+	fmtinstall('V', eipfmt);
+	fmtinstall('R', rrfmt);
+	fmtinstall('Q', rravfmt);
+	fmtinstall('H', sencodefmt);
+
+	dnvars.oldest = maxage;
+	dnvars.names = 0;
+}
+
+/*
+ *  hash for a domain name
+ */
+static ulong
+dnhash(char *name)
+{
+	ulong hash;
+	uchar *val = (uchar*)name;
+
+	for(hash = 0; *val; val++)
+		hash = (hash*13) + tolower(*val)-'a';
+	return hash % HTLEN;
+}
+
+/*
+ *  lookup a symbol.  if enter is not zero and the name is
+ *  not found, create it.
+ */
+DN*
+dnlookup(char *name, int class, int enter)
+{
+	DN **l;
+	DN *dp;
+
+	l = &ht[dnhash(name)];
+	lock(&dnlock);
+	for(dp = *l; dp; dp = dp->next) {
+		assert(dp->magic == DNmagic);
+		if(dp->class == class && cistrcmp(dp->name, name) == 0){
+			dp->referenced = now;
+			unlock(&dnlock);
+			return dp;
+		}
+		l = &dp->next;
+	}
+	if(enter == 0){
+		unlock(&dnlock);
+		return 0;
+	}
+	dnvars.names++;
+	dp = emalloc(sizeof(*dp));
+	dp->magic = DNmagic;
+	dp->name = estrdup(name);
+	assert(dp->name != 0);
+	dp->class = class;
+	dp->rr = 0;
+	dp->next = 0;
+	dp->referenced = now;
+	*l = dp;
+	unlock(&dnlock);
+
+	return dp;
+}
+
+/*
+ *  dump the cache
+ */
+void
+dndump(char *file)
+{
+	DN *dp;
+	int i, fd;
+	RR *rp;
+
+	fd = open(file, OWRITE|OTRUNC);
+	if(fd < 0)
+		return;
+	lock(&dnlock);
+	for(i = 0; i < HTLEN; i++){
+		for(dp = ht[i]; dp; dp = dp->next){
+			fprint(fd, "%s\n", dp->name);
+			for(rp = dp->rr; rp; rp = rp->next)
+				fprint(fd, "	%R %c%c %lud/%lud\n", rp, rp->auth?'A':'U',
+					rp->db?'D':'N', rp->expire, rp->ttl);
+		}
+	}
+	unlock(&dnlock);
+	close(fd);
+}
+
+/*
+ *  purge all records
+ */
+void
+dnpurge(void)
+{
+	DN *dp;
+	RR *rp, *srp;
+	int i;
+
+	lock(&dnlock);
+
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next){
+			srp = rp = dp->rr;
+			dp->rr = nil;
+			for(; rp != nil; rp = rp->next)
+				rp->cached = 0;
+			rrfreelist(srp);
+		}
+
+	unlock(&dnlock);
+}
+
+/*
+ *  check the age of resource records, free any that have timed out
+ */
+void
+dnage(DN *dp)
+{
+	RR **l;
+	RR *rp, *next;
+	ulong diff;
+
+	diff = now - dp->referenced;
+	if(diff < Reserved)
+		return;
+
+	l = &dp->rr;
+	for(rp = dp->rr; rp; rp = next){
+		assert(rp->magic == RRmagic && rp->cached);
+		next = rp->next;
+		if(!rp->db)
+		if(rp->expire < now || diff > dnvars.oldest){
+			*l = next;
+			rp->cached = 0;
+			rrfree(rp);
+			continue;
+		}
+		l = &rp->next;
+	}
+}
+
+#define REF(x) if(x) x->refs++
+
+/*
+ *  our target is 4000 names cached, this should be larger on large servers
+ */
+#define TARGET 4000
+
+/*
+ *  periodicly sweep for old records and remove unreferenced domain names
+ *
+ *  only called when all other threads are locked out
+ */
+void
+dnageall(int doit)
+{
+	DN *dp, **l;
+	int i;
+	RR *rp;
+	static ulong nextage;
+
+	if(dnvars.names < TARGET && now < nextage && !doit){
+		dnvars.oldest = maxage;
+		return;
+	}
+
+	if(dnvars.names > TARGET)
+		dnvars.oldest /= 2;
+	nextage = now + maxage;
+
+	lock(&dnlock);
+
+	/* time out all old entries (and set refs to 0) */
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next){
+			dp->refs = 0;
+			dnage(dp);
+		}
+
+	/* mark all referenced domain names */
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next)
+			for(rp = dp->rr; rp; rp = rp->next){
+				REF(rp->owner);
+				if(rp->negative){
+					REF(rp->negsoaowner);
+					continue;
+				}
+				switch(rp->type){
+				case Thinfo:
+					REF(rp->cpu);
+					REF(rp->os);
+					break;
+				case Ttxt:
+					break;
+				case Tcname:
+				case Tmb:
+				case Tmd:
+				case Tmf:
+				case Tns:
+					REF(rp->host);
+					break;
+				case Tmg:
+				case Tmr:
+					REF(rp->mb);
+					break;
+				case Tminfo:
+					REF(rp->rmb);
+					REF(rp->mb);
+					break;
+				case Trp:
+					REF(rp->rmb);
+					REF(rp->rp);
+					break;
+				case Tmx:
+					REF(rp->host);
+					break;
+				case Ta:
+				case Taaaa:
+					REF(rp->ip);
+					break;
+				case Tptr:
+					REF(rp->ptr);
+					break;
+				case Tsoa:
+					REF(rp->host);
+					REF(rp->rmb);
+					break;
+				}
+			}
+
+	/* sweep and remove unreferenced domain names */
+	for(i = 0; i < HTLEN; i++){
+		l = &ht[i];
+		for(dp = *l; dp; dp = *l){
+			if(dp->rr == 0 && dp->refs == 0){
+				assert(dp->magic == DNmagic);
+				*l = dp->next;
+				if(dp->name)
+					free(dp->name);
+				dp->magic = ~dp->magic;
+				dnvars.names--;
+				free(dp);
+				continue;
+			}
+			l = &dp->next;
+		}
+	}
+
+	unlock(&dnlock);
+}
+
+/*
+ *  timeout all database records (used when rereading db)
+ */
+void
+dnagedb(void)
+{
+	DN *dp;
+	int i;
+	RR *rp;
+	static ulong nextage;
+
+	lock(&dnlock);
+
+	/* time out all database entries */
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next)
+			for(rp = dp->rr; rp; rp = rp->next)
+				if(rp->db)
+					rp->expire = 0;
+
+	unlock(&dnlock);
+}
+
+/*
+ *  mark all local db records about my area as authoritative, time out any others
+ */
+void
+dnauthdb(void)
+{
+	DN *dp;
+	int i;
+	Area *area;
+	RR *rp;
+	static ulong nextage;
+
+	lock(&dnlock);
+
+	/* time out all database entries */
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next){
+			area = inmyarea(dp->name);
+			for(rp = dp->rr; rp; rp = rp->next)
+				if(rp->db){
+					if(area){
+						if(rp->ttl < area->soarr->soa->minttl)
+							rp->ttl = area->soarr->soa->minttl;
+						rp->auth = 1;
+					}
+					if(rp->expire == 0){
+						rp->db = 0;
+						dp->referenced = now - Reserved - 1;
+					}
+				}
+		}
+
+	unlock(&dnlock);
+}
+
+/*
+ *  keep track of other processes to know if we can
+ *  garbage collect.  block while garbage collecting.
+ */
+int
+getactivity(Request *req)
+{
+	int rv;
+
+	if(traceactivity) syslog(0, "dns", "get %d by %d", dnvars.active, getpid());
+	lock(&dnvars.lk);
+	while(dnvars.mutex){
+		unlock(&dnvars.lk);
+		sleep(200);
+		lock(&dnvars.lk);
+	}
+	rv = ++dnvars.active;
+	now = time(0);
+	req->id = ++dnvars.id;
+	unlock(&dnvars.lk);
+
+	return rv;
+}
+void
+putactivity(void)
+{
+	static ulong lastclean;
+
+	if(traceactivity) syslog(0, "dns", "put %d by %d", dnvars.active, getpid());
+	lock(&dnvars.lk);
+	dnvars.active--;
+	assert(dnvars.active >= 0); /* "dnvars.active %d", dnvars.active */;
+
+	/*
+	 *  clean out old entries and check for new db periodicly
+	 */
+	if(dnvars.mutex || (needrefresh == 0 && dnvars.active > 0)){
+		unlock(&dnvars.lk);
+		return;
+	}
+
+	/* wait till we're alone */
+	dnvars.mutex = 1;
+	while(dnvars.active > 0){
+		unlock(&dnvars.lk);
+		sleep(100);
+		lock(&dnvars.lk);
+	}
+	unlock(&dnvars.lk);
+
+	db2cache(needrefresh);
+	dnageall(0);
+
+	/* let others back in */
+	lastclean = now;
+	needrefresh = 0;
+	dnvars.mutex = 0;
+}
+
+/*
+ *  Attach a single resource record to a domain name.
+ *	- Avoid duplicates with already present RR's
+ *	- Chain all RR's of the same type adjacent to one another
+ *	- chain authoritative RR's ahead of non-authoritative ones
+ */
+static void
+rrattach1(RR *new, int auth)
+{
+	RR **l;
+	RR *rp;
+	DN *dp;
+
+	assert(new->magic == RRmagic && !new->cached);
+
+	if(!new->db)
+		new->expire = new->ttl;
+	else
+		new->expire = now + Year;
+	dp = new->owner;
+	assert(dp->magic == DNmagic);
+	new->auth |= auth;
+	new->next = 0;
+
+	/*
+	 *  find first rr of the right type
+	 */
+	l = &dp->rr;
+	for(rp = *l; rp; rp = *l){
+		assert(rp->magic == RRmagic && rp->cached);
+		if(rp->type == new->type)
+			break;
+		l = &rp->next;
+	}
+
+	/*
+	 *  negative entries replace positive entries
+	 *  positive entries replace negative entries
+	 *  newer entries replace older entries with the same fields
+	 */
+	for(rp = *l; rp; rp = *l){
+		assert(rp->magic == RRmagic && rp->cached);
+		if(rp->type != new->type)
+			break;
+
+		if(rp->db == new->db && rp->auth == new->auth){
+			/* negative drives out positive and vice versa */
+			if(rp->negative != new->negative){
+				*l = rp->next;
+				rp->cached = 0;
+				rrfree(rp);
+				continue;
+			}
+
+			/* all things equal, pick the newer one */
+			if(rp->arg0 == new->arg0 && rp->arg1 == new->arg1){
+				/* new drives out old */
+				if(new->ttl > rp->ttl || new->expire > rp->expire){
+					*l = rp->next;
+					rp->cached = 0;
+					rrfree(rp);
+					continue;
+				} else {
+					rrfree(new);
+					return;
+				}
+			}
+
+			/*  Hack for pointer records.  This makes sure
+			 *  the ordering in the list reflects the ordering
+			 *  received or read from the database
+			 */
+			if(rp->type == Tptr){
+				if(!rp->negative && !new->negative
+				&& rp->ptr->ordinal > new->ptr->ordinal)
+					break;
+			}
+		}
+		l = &rp->next;
+	}
+
+	/*
+	 *  add to chain
+	 */
+	new->cached = 1;
+	new->next = *l;
+	*l = new;
+}
+
+/*
+ *  Attach a list of resource records to a domain name.
+ *	- Avoid duplicates with already present RR's
+ *	- Chain all RR's of the same type adjacent to one another
+ *	- chain authoritative RR's ahead of non-authoritative ones
+ *	- remove any expired RR's
+ */
+void
+rrattach(RR *rp, int auth)
+{
+	RR *next;
+
+	lock(&dnlock);
+	for(; rp; rp = next){
+		next = rp->next;
+		rp->next = 0;
+
+		/* avoid any outside spoofing */
+		if(cachedb && !rp->db && inmyarea(rp->owner->name))
+			rrfree(rp);
+		else
+			rrattach1(rp, auth);
+	}
+	unlock(&dnlock);
+}
+
+/*
+ *  allocate a resource record of a given type
+ */
+RR*
+rralloc(int type)
+{
+	RR *rp;
+
+	rp = emalloc(sizeof(*rp));
+	rp->magic = RRmagic;
+	rp->pc = getcallerpc(&type);
+	rp->type = type;
+	switch(type){
+	case Tsoa:
+		rp->soa = emalloc(sizeof(*rp->soa));
+		rp->soa->slaves = nil;
+		break;
+	case Tkey:
+		rp->key = emalloc(sizeof(*rp->key));
+		break;
+	case Tcert:
+		rp->cert = emalloc(sizeof(*rp->cert));
+		break;
+	case Tsig:
+		rp->sig = emalloc(sizeof(*rp->sig));
+		break;
+	case Tnull:
+		rp->null = emalloc(sizeof(*rp->null));
+		break;
+	}
+	rp->ttl = 0;
+	rp->expire = 0;
+	rp->next = 0;
+	return rp;
+}
+
+/*
+ *  free a resource record and any related structs
+ */
+void
+rrfree(RR *rp)
+{
+	DN *dp;
+	RR *nrp;
+	Txt *t;
+
+	assert(rp->magic = RRmagic);
+	assert(!rp->cached);
+
+	dp = rp->owner;
+	if(dp){
+		assert(dp->magic == DNmagic);
+		for(nrp = dp->rr; nrp; nrp = nrp->next)
+			assert(nrp != rp); /* "rrfree of live rr" */;
+	}
+
+	switch(rp->type){
+	case Tsoa:
+		freeserverlist(rp->soa->slaves);
+		free(rp->soa);
+		break;
+	case Tkey:
+		free(rp->key->data);
+		free(rp->key);
+		break;
+	case Tcert:
+		free(rp->cert->data);
+		free(rp->cert);
+		break;
+	case Tsig:
+		free(rp->sig->data);
+		free(rp->sig);
+		break;
+	case Tnull:
+		free(rp->null->data);
+		free(rp->null);
+		break;
+	case Ttxt:
+		while(rp->txt != nil){
+			t = rp->txt;
+			rp->txt = t->next;
+			free(t->p);
+			free(t);
+		}
+		break;
+	}
+
+	rp->magic = ~rp->magic;
+	free(rp);
+}
+
+/*
+ *  free a list of resource records and any related structs
+ */
+void
+rrfreelist(RR *rp)
+{
+	RR *next;
+
+	for(; rp; rp = next){
+		next = rp->next;
+		rrfree(rp);
+	}
+}
+
+extern RR**
+rrcopy(RR *rp, RR **last)
+{
+	RR *nrp;
+	SOA *soa;
+	Key *key;
+	Cert *cert;
+	Sig *sig;
+	Null *null;
+	Txt *t, *nt, **l;
+
+	nrp = rralloc(rp->type);
+	switch(rp->type){
+	case Ttxt:
+		*nrp = *rp;
+		l = &nrp->txt;
+		*l = nil;
+		for(t = rp->txt; t != nil; t = t->next){
+			nt = emalloc(sizeof(*nt));
+			nt->p = estrdup(t->p);
+			nt->next = nil;
+			*l = nt;
+			l = &nt->next;
+		}
+		break;
+	case Tsoa:
+		soa = nrp->soa;
+		*nrp = *rp;
+		nrp->soa = soa;
+		*nrp->soa = *rp->soa;
+		nrp->soa->slaves = copyserverlist(rp->soa->slaves);
+		break;
+	case Tkey:
+		key = nrp->key;
+		*nrp = *rp;
+		nrp->key = key;
+		*key = *rp->key;
+		key->data = emalloc(key->dlen);
+		memmove(key->data, rp->key->data, rp->key->dlen);
+		break;
+	case Tsig:
+		sig = nrp->sig;
+		*nrp = *rp;
+		nrp->sig = sig;
+		*sig = *rp->sig;
+		sig->data = emalloc(sig->dlen);
+		memmove(sig->data, rp->sig->data, rp->sig->dlen);
+		break;
+	case Tcert:
+		cert = nrp->cert;
+		*nrp = *rp;
+		nrp->cert = cert;
+		*cert = *rp->cert;
+		cert->data = emalloc(cert->dlen);
+		memmove(cert->data, rp->cert->data, rp->cert->dlen);
+		break;
+	case Tnull:
+		null = nrp->null;
+		*nrp = *rp;
+		nrp->null = null;
+		*null = *rp->null;
+		null->data = emalloc(null->dlen);
+		memmove(null->data, rp->null->data, rp->null->dlen);
+		break;
+	default:
+		*nrp = *rp;
+		break;
+	}
+	nrp->cached = 0;
+	nrp->next = 0;
+	*last = nrp;
+	return &nrp->next;
+}
+
+/*
+ *  lookup a resource record of a particular type and
+ *  class attached to a domain name.  Return copies.
+ *
+ *  Priority ordering is:
+ *	db authoritative
+ *	not timed out network authoritative
+ *	not timed out network unauthoritative
+ *	unauthoritative db
+ *
+ *  if flag NOneg is set, don't return negative cached entries.
+ *  return nothing instead.
+ */
+RR*
+rrlookup(DN *dp, int type, int flag)
+{
+	RR *rp, *first, **last;
+
+	assert(dp->magic == DNmagic);
+
+	first = 0;
+	last = &first;
+	lock(&dnlock);
+
+	/* try for an authoritative db entry */
+	for(rp = dp->rr; rp; rp = rp->next){
+		assert(rp->magic == RRmagic && rp->cached);
+		if(rp->db)
+		if(rp->auth)
+		if(tsame(type, rp->type))
+			last = rrcopy(rp, last);
+	}
+	if(first)
+		goto out;
+
+	/* try for an living authoritative network entry */
+	for(rp = dp->rr; rp; rp = rp->next){
+		if(!rp->db)
+		if(rp->auth)
+		if(rp->ttl + 60 > now)
+		if(tsame(type, rp->type)){
+			if(flag == NOneg && rp->negative)
+				goto out;
+			last = rrcopy(rp, last);
+		}
+	}
+	if(first)
+		goto out;
+
+	/* try for an living unauthoritative network entry */
+	for(rp = dp->rr; rp; rp = rp->next){
+		if(!rp->db)
+		if(rp->ttl + 60 > now)
+		if(tsame(type, rp->type)){
+			if(flag == NOneg && rp->negative)
+				goto out;
+			last = rrcopy(rp, last);
+		}
+	}
+	if(first)
+		goto out;
+
+	/* try for an unauthoritative db entry */
+	for(rp = dp->rr; rp; rp = rp->next){
+		if(rp->db)
+		if(tsame(type, rp->type))
+			last = rrcopy(rp, last);
+	}
+	if(first)
+		goto out;
+
+	/* otherwise, settle for anything we got (except for negative caches)  */
+	for(rp = dp->rr; rp; rp = rp->next){
+		if(tsame(type, rp->type)){
+			if(rp->negative)
+				goto out;
+			last = rrcopy(rp, last);
+		}
+	}
+
+out:
+	unlock(&dnlock);
+	unique(first);
+	return first;
+}
+
+/*
+ *  convert an ascii RR type name to its integer representation
+ */
+int
+rrtype(char *atype)
+{
+	int i;
+
+	for(i = 0; i <= Tall; i++)
+		if(rrtname[i] && strcmp(rrtname[i], atype) == 0)
+			return i;
+
+	// make any a synonym for all
+	if(strcmp(atype, "any") == 0)
+		return Tall;
+	return atoi(atype);
+}
+
+/*
+ *  convert an integer RR type to it's ascii name
+ */
+char*
+rrname(int type, char *buf, int len)
+{
+	char *t;
+
+	t = 0;
+	if(type <= Tall)
+		t = rrtname[type];
+	if(t==0){
+		snprint(buf, len, "%d", type);
+		t = buf;
+	}
+	return t;
+}
+
+/*
+ *  return 0 if not a supported rr type
+ */
+int
+rrsupported(int type)
+{
+	if(type < 0 || type >Tall)
+		return 0;
+	return rrtname[type] != 0;
+}
+
+/*
+ *  compare 2 types
+ */
+int
+tsame(int t1, int t2)
+{
+	return t1 == t2 || t1 == Tall;
+}
+
+/*
+ *  Add resource records to a list, duplicate them if they are cached
+ *  RR's since these are shared.
+ */
+RR*
+rrcat(RR **start, RR *rp)
+{
+	RR **last;
+
+	last = start;
+	while(*last != 0)
+		last = &(*last)->next;
+
+	*last = rp;
+	return *start;
+}
+
+/*
+ *  remove negative cache rr's from an rr list
+ */
+RR*
+rrremneg(RR **l)
+{
+	RR **nl, *rp;
+	RR *first;
+
+	first = nil;
+	nl = &first;
+	while(*l != nil){
+		rp = *l;
+		if(rp->negative){
+			*l = rp->next;
+			*nl = rp;
+			nl = &rp->next;
+			*nl = nil;
+		} else
+			l = &rp->next;
+	}
+
+	return first;
+}
+
+/*
+ *  remove rr's of a particular type from an rr list
+ */
+RR*
+rrremtype(RR **l, int type)
+{
+	RR **nl, *rp;
+	RR *first;
+
+	first = nil;
+	nl = &first;
+	while(*l != nil){
+		rp = *l;
+		if(rp->type == type){
+			*l = rp->next;
+			*nl = rp;
+			nl = &rp->next;
+			*nl = nil;
+		} else
+			l = &(*l)->next;
+	}
+
+	return first;
+}
+
+/*
+ *  print conversion for rr records
+ */
+int
+rrfmt(Fmt *f)
+{
+	RR *rp;
+	char *strp;
+	Fmt fstr;
+	int rv;
+	char buf[Domlen];
+	Server *s;
+	Txt *t;
+
+	fmtstrinit(&fstr);
+
+	rp = va_arg(f->args, RR*);
+	if(rp == 0){
+		fmtprint(&fstr, "<null>");
+		goto out;
+	}
+
+	fmtprint(&fstr, "%s %s", rp->owner->name,
+		rrname(rp->type, buf, sizeof buf));
+
+	if(rp->negative){
+		fmtprint(&fstr, "\tnegative - rcode %d", rp->negrcode);
+		goto out;
+	}
+
+	switch(rp->type){
+	case Thinfo:
+		fmtprint(&fstr, "\t%s %s", rp->cpu->name, rp->os->name);
+		break;
+	case Tcname:
+	case Tmb:
+	case Tmd:
+	case Tmf:
+	case Tns:
+		fmtprint(&fstr, "\t%s", rp->host->name);
+		break;
+	case Tmg:
+	case Tmr:
+		fmtprint(&fstr, "\t%s", rp->mb->name);
+		break;
+	case Tminfo:
+		fmtprint(&fstr, "\t%s %s", rp->mb->name, rp->rmb->name);
+		break;
+	case Tmx:
+		fmtprint(&fstr, "\t%lud %s", rp->pref, rp->host->name);
+		break;
+	case Ta:
+	case Taaaa:
+		fmtprint(&fstr, "\t%s", rp->ip->name);
+		break;
+	case Tptr:
+//		fmtprint(&fstr, "\t%s(%lud)", rp->ptr->name, rp->ptr->ordinal);
+		fmtprint(&fstr, "\t%s", rp->ptr->name);
+		break;
+	case Tsoa:
+		fmtprint(&fstr, "\t%s %s %lud %lud %lud %lud %lud", rp->host->name,
+			rp->rmb->name, rp->soa->serial, rp->soa->refresh, rp->soa->retry,
+			rp->soa->expire, rp->soa->minttl);
+		for(s = rp->soa->slaves; s != nil; s = s->next)
+			fmtprint(&fstr, " %s", s->name);
+		break;
+	case Tnull:
+		fmtprint(&fstr, "\t%.*H", rp->null->dlen, rp->null->data);
+		break;
+	case Ttxt:
+		fmtprint(&fstr, "\t");
+		for(t = rp->txt; t != nil; t = t->next)
+			fmtprint(&fstr, "%s", t->p);
+		break;
+	case Trp:
+		fmtprint(&fstr, "\t%s %s", rp->rmb->name, rp->rp->name);
+		break;
+	case Tkey:
+		fmtprint(&fstr, "\t%d %d %d", rp->key->flags, rp->key->proto,
+			rp->key->alg);
+		break;
+	case Tsig:
+		fmtprint(&fstr, "\t%d %d %d %lud %lud %lud %d %s",
+			rp->sig->type, rp->sig->alg, rp->sig->labels, rp->sig->ttl,
+			rp->sig->exp, rp->sig->incep, rp->sig->tag, rp->sig->signer->name);
+		break;
+	case Tcert:
+		fmtprint(&fstr, "\t%d %d %d",
+			rp->sig->type, rp->sig->tag, rp->sig->alg);
+		break;
+	default:
+		break;
+	}
+out:
+	strp = fmtstrflush(&fstr);
+	rv = fmtstrcpy(f, strp);
+	free(strp);
+	return rv;
+}
+
+/*
+ *  print conversion for rr records in attribute value form
+ */
+int
+rravfmt(Fmt *f)
+{
+	RR *rp;
+	char *strp;
+	Fmt fstr;
+	int rv;
+	Server *s;
+	Txt *t;
+	int quote;
+
+	fmtstrinit(&fstr);
+
+	rp = va_arg(f->args, RR*);
+	if(rp == 0){
+		fmtprint(&fstr, "<null>");
+		goto out;
+	}
+
+	if(rp->type == Tptr)
+		fmtprint(&fstr, "ptr=%s", rp->owner->name);
+	else
+		fmtprint(&fstr, "dom=%s", rp->owner->name);
+
+	switch(rp->type){
+	case Thinfo:
+		fmtprint(&fstr, " cpu=%s os=%s", rp->cpu->name, rp->os->name);
+		break;
+	case Tcname:
+		fmtprint(&fstr, " cname=%s", rp->host->name);
+		break;
+	case Tmb:
+	case Tmd:
+	case Tmf:
+		fmtprint(&fstr, " mbox=%s", rp->host->name);
+		break;
+	case Tns:
+		fmtprint(&fstr,  " ns=%s", rp->host->name);
+		break;
+	case Tmg:
+	case Tmr:
+		fmtprint(&fstr, " mbox=%s", rp->mb->name);
+		break;
+	case Tminfo:
+		fmtprint(&fstr, " mbox=%s mbox=%s", rp->mb->name, rp->rmb->name);
+		break;
+	case Tmx:
+		fmtprint(&fstr, " pref=%lud mx=%s", rp->pref, rp->host->name);
+		break;
+	case Ta:
+	case Taaaa:
+		fmtprint(&fstr, " ip=%s", rp->ip->name);
+		break;
+	case Tptr:
+		fmtprint(&fstr, " dom=%s", rp->ptr->name);
+		break;
+	case Tsoa:
+		fmtprint(&fstr, " ns=%s mbox=%s serial=%lud refresh=%lud retry=%lud expire=%lud ttl=%lud",
+			rp->host->name, rp->rmb->name, rp->soa->serial,
+			rp->soa->refresh, rp->soa->retry,
+			rp->soa->expire, rp->soa->minttl);
+		for(s = rp->soa->slaves; s != nil; s = s->next)
+			fmtprint(&fstr, " dnsslave=%s", s->name);
+		break;
+	case Tnull:
+		fmtprint(&fstr, " null=%.*H", rp->null->dlen, rp->null->data);
+		break;
+	case Ttxt:
+		fmtprint(&fstr, " txt=");
+		quote = 0;
+		for(t = rp->txt; t != nil; t = t->next)
+			if(strchr(t->p, ' '))
+				quote = 1;
+		if(quote)
+			fmtprint(&fstr, "\"");
+		for(t = rp->txt; t != nil; t = t->next)
+			fmtprint(&fstr, "%s", t->p);
+		if(quote)
+			fmtprint(&fstr, "\"");
+		break;
+	case Trp:
+		fmtprint(&fstr, " rp=%s txt=%s", rp->rmb->name, rp->rp->name);
+		break;
+	case Tkey:
+		fmtprint(&fstr, " flags=%d proto=%d alg=%d",
+			rp->key->flags, rp->key->proto, rp->key->alg);
+		break;
+	case Tsig:
+		fmtprint(&fstr, " type=%d alg=%d labels=%d ttl=%lud exp=%lud incep=%lud tag=%d signer=%s",
+			rp->sig->type, rp->sig->alg, rp->sig->labels, rp->sig->ttl,
+			rp->sig->exp, rp->sig->incep, rp->sig->tag, rp->sig->signer->name);
+		break;
+	case Tcert:
+		fmtprint(&fstr, " type=%d tag=%d alg=%d",
+			rp->sig->type, rp->sig->tag, rp->sig->alg);
+		break;
+	default:
+		break;
+	}
+out:
+	strp = fmtstrflush(&fstr);
+	rv = fmtstrcpy(f, strp);
+	free(strp);
+	return rv;
+}
+
+void
+warning(char *fmt, ...)
+{
+	char dnserr[128];
+	va_list arg;
+
+	va_start(arg, fmt);
+	vseprint(dnserr, dnserr+sizeof(dnserr), fmt, arg);
+	va_end(arg);
+	syslog(1, "dns", dnserr);
+}
+
+/*
+ *  create a slave process to handle a request to avoid one request blocking
+ *  another
+ */
+void
+slave(Request *req)
+{
+	static int slaveid;
+
+	if(req->isslave)
+		return;		/* we're already a slave process */
+
+	/* limit parallelism */
+	if(getactivity(req) > Maxactive){
+		putactivity();
+		return;
+	}
+
+	switch(rfork(RFPROC|RFNOTEG|RFMEM|RFNOWAIT)){
+	case -1:
+		putactivity();
+		break;
+	case 0:
+		req->isslave = 1;
+		break;
+	default:
+		longjmp(req->mret, 1);
+	}
+}
+
+/*
+ *  chasing down double free's
+ */
+void
+dncheck(void *p, int dolock)
+{
+	int i;
+	DN *dp;
+	RR *rp;
+
+	if(p != nil){
+		dp = p;
+		assert(dp->magic == DNmagic);
+	}
+
+	if(!testing)
+		return;
+
+	if(dolock)
+		lock(&dnlock);
+	for(i = 0; i < HTLEN; i++)
+		for(dp = ht[i]; dp; dp = dp->next){
+			assert(dp != p);
+			assert(dp->magic == DNmagic);
+			for(rp = dp->rr; rp; rp = rp->next){
+				assert(rp->magic == RRmagic);
+				assert(rp->cached);
+				assert(rp->owner == dp);
+			}
+		}
+	if(dolock)
+		unlock(&dnlock);
+}
+
+static int
+rrequiv(RR *r1, RR *r2)
+{
+	return r1->owner == r2->owner
+		&& r1->type == r2->type
+		&& r1->arg0 == r2->arg0
+		&& r1->arg1 == r2->arg1;
+}
+
+void
+unique(RR *rp)
+{
+	RR **l, *nrp;
+
+	for(; rp; rp = rp->next){
+		l = &rp->next;
+		for(nrp = *l; nrp; nrp = *l){
+			if(rrequiv(rp, nrp)){
+				*l = nrp->next;
+				rrfree(nrp);
+			} else
+				l = &nrp->next;
+		}
+	}
+}
+
+/*
+ *  true if second domain is subsumed by the first
+ */
+int
+subsume(char *higher, char *lower)
+{
+	int hn, ln;
+
+	ln = strlen(lower);
+	hn = strlen(higher);
+	if(ln < hn)
+		return 0;
+
+	if(cistrcmp(lower + ln - hn, higher) != 0)
+		return 0;
+
+	if(ln > hn && hn != 0 && lower[ln - hn - 1] != '.')
+		return 0;
+
+	return 1;
+}
+
+/*
+ *  randomize the order we return items to provide some
+ *  load balancing for servers.
+ *
+ *  only randomize the first class of entries
+ */
+RR*
+randomize(RR *rp)
+{
+	RR *first, *last, *x, *base;
+	ulong n;
+
+	if(rp == nil || rp->next == nil)
+		return rp;
+
+	/* just randomize addresses and mx's */
+	for(x = rp; x; x = x->next)
+		if(x->type != Ta && x->type != Tmx && x->type != Tns)
+			return rp;
+
+	base = rp; 
+
+	n = rand();
+	last = first = nil;
+	while(rp != nil){
+		/* stop randomizing if we've moved past our class */
+		if(base->auth != rp->auth || base->db != rp->db){
+			last->next = rp;
+			break;
+		}
+
+		/* unchain */
+		x = rp;
+		rp = x->next;
+		x->next = nil;
+
+		if(n&1){
+			/* add to tail */
+			if(last == nil)
+				first = x;
+			else
+				last->next = x;
+			last = x;
+		} else {
+			/* add to head */
+			if(last == nil)
+				last = x;
+			x->next = first;
+			first = x;
+		}
+
+		/* reroll the dice */
+		n >>= 1;
+	}
+	return first;
+}
+
+static int
+sencodefmt(Fmt *f)
+{
+	char *out;
+	char *buf;
+	int i, len;
+	int ilen;
+	int rv;
+	uchar *b;
+	char obuf[64];	// rsc optimization
+
+	if(!(f->flags&FmtPrec) || f->prec < 1)
+		goto error;
+
+	b = va_arg(f->args, uchar*);
+	if(b == nil)
+		goto error;
+
+	/* if it's a printable, go for it */
+	len = f->prec;
+	for(i = 0; i < len; i++)
+		if(!isprint(b[i]))
+			break;
+	if(i == len){
+		if(len >= sizeof obuf)
+			len = sizeof(obuf)-1;
+		memmove(obuf, b, len);
+		obuf[len] = 0;
+		fmtstrcpy(f, obuf);
+		return 0;
+	}
+
+	ilen = f->prec;
+	f->prec = 0;
+	f->flags &= ~FmtPrec;
+	switch(f->r){
+	case '<':
+		len = (8*ilen+4)/5 + 3;
+		break;
+	case '[':
+		len = (8*ilen+5)/6 + 4;
+		break;
+	case 'H':
+		len = 2*ilen + 1;
+		break;
+	default:
+		goto error;
+	}
+
+	if(len > sizeof(obuf)){
+		buf = malloc(len);
+		if(buf == nil)
+			goto error;
+	} else
+		buf = obuf;
+
+	// convert
+	out = buf;
+	switch(f->r){
+	case '<':
+		rv = enc32(out, len, b, ilen);
+		break;
+	case '[':
+		rv = enc64(out, len, b, ilen);
+		break;
+	case 'H':
+		rv = enc16(out, len, b, ilen);
+		break;
+	default:
+		rv = -1;
+		break;
+	}
+	if(rv < 0)
+		goto error;
+
+	fmtstrcpy(f, buf);
+	if(buf != obuf)
+		free(buf);
+	return 0;
+
+error:
+	return fmtstrcpy(f, "<encodefmt>");
+
+}
+
+void*
+emalloc(int size)
+{
+	char *x;
+
+	x = mallocz(size, 1);
+	if(x == nil)
+		abort();
+	setmalloctag(x, getcallerpc(&size));
+	return x;
+}
+
+char*
+estrdup(char *s)
+{
+	int size;
+	char *p;
+
+	size = strlen(s)+1;
+	p = mallocz(size, 0);
+	if(p == nil)
+		abort();
+	memmove(p, s, size);
+	setmalloctag(p, getcallerpc(&s));
+	return p;
+}
+
+/*
+ *  create a pointer record
+ */
+static RR*
+mkptr(DN *dp, char *ptr, ulong ttl)
+{
+	DN *ipdp;
+	RR *rp;
+
+	ipdp = dnlookup(ptr, Cin, 1);
+
+	rp = rralloc(Tptr);
+	rp->ptr = dp;
+	rp->owner = ipdp;
+	rp->db = 1;
+	if(ttl)
+		rp->ttl = ttl;
+	return rp;
+}
+
+/*
+ *  look for all ip addresses in this network and make
+ *  pointer records for them.
+ */
+void
+dnptr(uchar *net, uchar *mask, char *dom, int bytes, int ttl)
+{
+	int i, j;
+	DN *dp;
+	RR *rp, *nrp, *first, **l;
+	uchar ip[IPaddrlen];
+	uchar nnet[IPaddrlen];
+	char ptr[Domlen];
+	char *p, *e;
+
+	l = &first;
+	first = nil;
+	for(i = 0; i < HTLEN; i++){
+		for(dp = ht[i]; dp; dp = dp->next){
+			for(rp = dp->rr; rp; rp = rp->next){
+				if(rp->type != Ta || rp->negative)
+					continue;
+				parseip(ip, rp->ip->name);
+				maskip(ip, mask, nnet);
+				if(ipcmp(net, nnet) != 0)
+					continue;
+				p = ptr;
+				e = ptr+sizeof(ptr);
+				for(j = IPaddrlen-1; j >= IPaddrlen-bytes; j--)
+					p = seprint(p, e, "%d.", ip[j]);
+				seprint(p, e, "%s", dom);
+				nrp = mkptr(dp, ptr, ttl);
+				*l = nrp;
+				l = &nrp->next;
+			}
+		}
+	}
+
+	for(rp = first; rp != nil; rp = nrp){
+		nrp = rp->next;
+		rp->next = nil;
+		rrattach(rp, 1);
+	}
+}
+
+void
+freeserverlist(Server *s)
+{
+	Server *next;
+
+	for(; s != nil; s = next){
+		next = s->next;
+		free(s);
+	}
+}
+
+void
+addserver(Server **l, char *name)
+{
+	Server *s;
+
+	while(*l)
+		l = &(*l)->next;
+	s = malloc(sizeof(Server)+strlen(name)+1);
+	if(s == nil)
+		return;
+	s->name = (char*)(s+1);
+	strcpy(s->name, name);
+	s->next = nil;
+	*l = s;
+}
+
+Server*
+copyserverlist(Server *s)
+{
+	Server *ns;
+
+	
+	for(ns = nil; s != nil; s = s->next)
+		addserver(&ns, s->name);
+	return ns;
+}