More async resolver refinements:

- yp_main.c: Always add the resolver socket to the set of fds
  monitored by select(). It can happen that pending == 0 but we
  still have some data in the socket buffer from an old query.
  This way, the data will be flushed in a timely manner.

- yp_extern.h: remove proto for yp_dns_pending() since we don't need
  it anynmore.

- yp_server.c: call yp_async_lookup_name()/yp_async_lookup_addr()
  functions with the svc_req pointer as an arg instead of the xprt.
  (The svc_req struct includes a pointer to the transport handle,
  and it also has the service version number which the async DNS
  code will need. (see below))

- yp_dnslookup.c:

   o Nuke yp_dns_pending() since we don't need it anymore.
   o In yp_run_dnsq(), swallow up and ignore replies if no requests
     are pending or the ID doesn't match any of the IDs in the queue.
   o In yp_send_dns_reply(), we assume that we will always be
     replying to an NIS v2 client. While this will probably always
     be the case, we do support the v1 'match' procedure, and it
     has a different result struct than v2. For completeness,
     support replying to both NIS v1 and v2 clients.
   o Update the queue entry structure to include a member to
     keep track of the NIS version number.
   o Have yp_async_lookup_name/addr() extract the version number
     from the svc_req structure and save it with the queue entry
     for yp_send_dns_reply() to inspect later.
   o Add some comments.

4 files changed, 115 insertions, 54 deletions

diff --git a/usr.sbin/ypserv/yp_dnslookup.c b/usr.sbin/ypserv/yp_dnslookup.c
index 7e350a2..91eebc3 100644
--- a/usr.sbin/ypserv/yp_dnslookup.c
+++ b/usr.sbin/ypserv/yp_dnslookup.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995
+ * Copyright (c) 1995, 1996
  *	Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -29,7 +29,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: yp_dnslookup.c,v 1.4 1996/12/22 22:30:54 wpaul Exp $
+ *	$Id: yp_dnslookup.c,v 1.9 1996/12/25 17:52:35 wpaul Exp $
  */
 
 /*
@@ -65,7 +65,7 @@
 #include "yp_extern.h"
 
 #ifndef lint
-static const char rcsid[] = "$Id: yp_dnslookup.c,v 1.4 1996/12/22 22:30:54 wpaul Exp $";
+static const char rcsid[] = "$Id: yp_dnslookup.c,v 1.9 1996/12/25 17:52:35 wpaul Exp $";
 #endif
 
 static char *parse(hp)
@@ -106,9 +106,9 @@ struct circleq_dnsentry {
 	SVCXPRT *xprt;
 	unsigned long xid;
 	struct sockaddr_in client_addr;
+	unsigned long ypvers;
 	unsigned long id;
 	unsigned long ttl;
-	unsigned long sent;
 	unsigned long type;
 	unsigned short prot_type;
 	char **domain;
@@ -137,11 +137,6 @@ int yp_init_resolver()
 	return(0);
 }
 
-int yp_dnsq_pending()
-{
-	return(pending);
-}
-
 static struct circleq_dnsentry *yp_malloc_dnsent()
 {
 	register struct circleq_dnsentry *q;
@@ -202,7 +197,7 @@ static struct circleq_dnsentry *yp_find_dnsqent(id)
 	register struct circleq_dnsentry *q;
 
 	for (q = qhead.cqh_first; q != (void *)&qhead; q = q->links.cqe_next) {
-		if (q->id == id)
+		if (id == q->id)
 			return(q);
 	}
 	return (NULL);
@@ -212,25 +207,60 @@ static void yp_send_dns_reply(q, buf)
 	struct circleq_dnsentry *q;
 	char *buf;
 {
-	ypresp_val result;
+	ypresponse result_v1;
+	ypresp_val result_v2;
 	unsigned long xid;
 	struct sockaddr_in client_addr;
+	xdrproc_t xdrfunc;
+	char *result;
 
-	bzero((char *)&result, sizeof(result));
-
-	if (buf == NULL)
-		result.stat = YP_NOKEY;
-	else {
-		result.val.valdat_len = strlen(buf);
-		result.val.valdat_val = buf;
-		result.stat = YP_TRUE;
+	/*
+	 * Set up correct reply struct and
+	 * XDR filter depending on ypvers.
+	 */
+	switch(q->ypvers) {
+	case YPVERS:
+		bzero((char *)&result_v2, sizeof(result_v2));
+
+		if (buf == NULL)
+			result_v2.stat = YP_NOKEY;
+		else {
+			result_v2.val.valdat_len = strlen(buf);
+			result_v2.val.valdat_val = buf;
+			result_v2.stat = YP_TRUE;
+		}
+		result = (char *)&result_v2;
+		xdrfunc = (xdrproc_t)xdr_ypresp_val;
+		break;
+	case YPOLDVERS:
+		/*
+		 * The odds are we will _never_ execute this
+		 * particular code, but we include it anyway
+		 * for the sake of completeness.
+		 */
+		bzero((char *)&result_v1, sizeof(result_v1));
+		result_v1.yp_resptype = YPRESP_VAL;
+#		define YPVAL ypresponse_u.yp_resp_valtype
+
+		if (buf == NULL)
+			result_v1.YPVAL.stat = YP_NOKEY;
+		else {
+			result_v1.YPVAL.val.valdat_len = strlen(buf);
+			result_v1.YPVAL.val.valdat_val = buf;
+			result_v1.YPVAL.stat = YP_TRUE;
+		}
+		result = (char *)&result_v1;
+		xdrfunc = (xdrproc_t)xdr_ypresponse;
+		break;
+	default:
+		yp_error("Bad YP program version (%lu)!",q->ypvers);
+			return;
+		break;
 	}
 
 	if (debug)
 		yp_error("Sending dns reply to %s (%lu)",
-					inet_ntoa(q->client_addr.sin_addr),
-					q->id);
-
+			inet_ntoa(q->client_addr.sin_addr), q->id);
 	/*
 	 * XXX This is disgusting. There's basically one transport
 	 * handle for UDP, but we're holding off on replying to a
@@ -245,20 +275,31 @@ static void yp_send_dns_reply(q, buf)
 	 * not even supported by the RPC library.
 	 */
 	/*
-	 * XXX Don't from the transaction ID for TCP handles.
+	 * XXX Don't frob the transaction ID for TCP handles.
 	 */
 	if (q->prot_type == SOCK_DGRAM)
 		xid = svcudp_set_xid(q->xprt, q->xid);
 	client_addr = q->xprt->xp_raddr;
 	q->xprt->xp_raddr = q->client_addr;
-	if (!svc_sendreply(q->xprt, xdr_ypresp_val, (char *)&result))
+
+	if (!svc_sendreply(q->xprt, xdrfunc, result))
 		yp_error("svc_sendreply failed");
+
+	/*
+	 * Now that we sent the reply,
+	 * put the handle back the way it was.
+	 */
 	if (q->prot_type == SOCK_DGRAM)
 		svcudp_set_xid(q->xprt, xid);
 	q->xprt->xp_raddr = client_addr;
+
 	return;
 }
 
+/*
+ * Decrement TTL on all queue entries, possibly nuking
+ * any that have been around too long without being serviced.
+ */
 void yp_prune_dnsq()
 {
 	register struct circleq_dnsentry *q;
@@ -279,10 +320,15 @@ void yp_prune_dnsq()
 	return;
 }
 
+/*
+ * Data is pending on the DNS socket; check for valid replies
+ * to our queries and dispatch them to waiting clients.
+ */
 void yp_run_dnsq()
 {
 	register struct circleq_dnsentry *q;
 	char buf[sizeof(HEADER) + MAXPACKET];
+	char retrybuf[MAXHOSTNAMELEN];
 	struct sockaddr_in sin;
 	int rval;
 	int len;
@@ -303,9 +349,16 @@ void yp_run_dnsq()
 		return;
 	}
 
+	/*
+	 * We may have data left in the socket that represents
+	 * replies to earlier queries that we don't care about
+	 * anymore. If there are no lookups pending or the packet
+	 * ID doesn't match any of the queue IDs, just drop it
+	 * on the floor.
+	 */
 	hptr = (HEADER *)&buf;
-	if ((q = yp_find_dnsqent(ntohs(hptr->id))) == NULL) {
-		/* bogus id -- ignore */
+	if (!pending || (q = yp_find_dnsqent(ntohs(hptr->id))) == NULL) {
+		/* ignore */
 		return;
 	}
 
@@ -314,9 +367,12 @@ void yp_run_dnsq()
 
 	hent = __dns_getanswer(buf, rval, q->name, q->type);
 
+	/*
+	 * If the lookup failed, try appending one of the domains
+	 * from resolv.conf. If we have no domains to test, the
+	 * query has failed.
+	 */
 	if (hent == NULL) {
-		char retrybuf[MAXHOSTNAMELEN];
-
 		if (h_errno == TRY_AGAIN && q->domain && *q->domain) {
 			snprintf(retrybuf, sizeof(retrybuf), "%s.%s",
 						q->name, *q->domain);
@@ -334,20 +390,24 @@ void yp_run_dnsq()
 		}
 	}
 
+	/* Got an answer ready for a client -- send it off. */
 	yp_send_dns_reply(q, parse(hent));
-
 	pending--;
 	CIRCLEQ_REMOVE(&qhead, q, links);
 	free(q->name);
 	free(q);
 
+	/* Decrement TTLs on other entries while we're here. */
 	yp_prune_dnsq();
 
 	return;
 }
 
-ypstat yp_async_lookup_name(xprt, name)
-	SVCXPRT	*xprt;
+/*
+ * Queue and transmit an asynchronous DNS hostname lookup.
+ */
+ypstat yp_async_lookup_name(rqstp, name)
+	struct svc_req *rqstp;
 	char *name;
 {
 	register struct circleq_dnsentry *q;
@@ -358,17 +418,17 @@ ypstat yp_async_lookup_name(xprt, name)
 
 	q->type = T_A;
 	q->ttl = DEF_TTL;
-	q->sent = 1;
-	q->xprt = xprt;
+	q->xprt = rqstp->rq_xprt;
+	q->ypvers = rqstp->rq_vers;
 	type = -1; len = sizeof(type);
-	if (getsockopt(xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
+	if (getsockopt(q->xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
 		yp_error("getsockopt failed: %s", strerror(errno));
 		return(YP_YPERR);
 	}
 	q->prot_type = type;
 	if (q->prot_type == SOCK_DGRAM)
-		q->xid = svcudp_get_xid(xprt);
-	q->client_addr = xprt->xp_raddr;
+		q->xid = svcudp_get_xid(q->xprt);
+	q->client_addr = q->xprt->xp_raddr;
 	if (!strchr(name, '.'))
 		q->domain = _res.dnsrch;
 	else
@@ -391,8 +451,11 @@ ypstat yp_async_lookup_name(xprt, name)
 	return(YP_TRUE);
 }
 
-ypstat yp_async_lookup_addr(xprt, addr)
-	SVCXPRT *xprt;
+/*
+ * Queue and transmit an asynchronous DNS IP address lookup.
+ */
+ypstat yp_async_lookup_addr(rqstp, addr)
+	struct svc_req *rqstp;
 	char *addr;
 {
 	register struct circleq_dnsentry *q;
@@ -414,18 +477,18 @@ ypstat yp_async_lookup_addr(xprt, addr)
 
 	q->type = T_PTR;
 	q->ttl = DEF_TTL;
-	q->sent = 1;
-	q->xprt = xprt;
+	q->xprt = rqstp->rq_xprt;
+	q->ypvers = rqstp->rq_vers;
 	q->domain = NULL;
 	type = -1; len = sizeof(type);
-	if (getsockopt(xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
+	if (getsockopt(q->xprt->xp_sock,SOL_SOCKET,SO_TYPE,&type,&len) == -1) {
 		yp_error("getsockopt failed: %s", strerror(errno));
 		return(YP_YPERR);
 	}
 	q->prot_type = type;
 	if (q->prot_type == SOCK_DGRAM)
-		q->xid = svcudp_get_xid(xprt);
-	q->client_addr = xprt->xp_raddr;
+		q->xid = svcudp_get_xid(q->xprt);
+	q->client_addr = q->xprt->xp_raddr;
 	q->id = yp_send_dns_query(buf, q->type);
 
 	if (q->id == 0) {
diff --git a/usr.sbin/ypserv/yp_extern.h b/usr.sbin/ypserv/yp_extern.h
index fc3e6dd..0fb7ab2 100644
--- a/usr.sbin/ypserv/yp_extern.h
+++ b/usr.sbin/ypserv/yp_extern.h
@@ -29,7 +29,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: yp_extern.h,v 1.3 1996/12/22 15:53:55 wpaul Exp $
+ *	$Id: yp_extern.h,v 1.4 1996/12/24 07:52:52 wpaul Exp $
  */
 #include <stdio.h>
 #include <string.h>
@@ -106,8 +106,7 @@ extern unsigned long	svcudp_get_xid __P(( SVCXPRT * ));
 #endif
 
 extern int	yp_init_resolver __P(( void ));
-extern int	yp_dnsq_pending __P(( void ));
 extern void	yp_run_dnsq __P(( void ));
 extern void	yp_prune_dnsq __P(( void ));
-extern ypstat	yp_async_lookup_name __P(( SVCXPRT *, char * ));
-extern ypstat	yp_async_lookup_addr __P(( SVCXPRT *, char * ));
+extern ypstat	yp_async_lookup_name __P(( struct svc_req *, char * ));
+extern ypstat	yp_async_lookup_addr __P(( struct svc_req *, char * ));
diff --git a/usr.sbin/ypserv/yp_main.c b/usr.sbin/ypserv/yp_main.c
index db40ac6..b172180 100644
--- a/usr.sbin/ypserv/yp_main.c
+++ b/usr.sbin/ypserv/yp_main.c
@@ -29,7 +29,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: yp_main.c,v 1.4 1996/12/22 15:54:03 wpaul Exp $
+ *	$Id: yp_main.c,v 1.5 1996/12/24 07:52:52 wpaul Exp $
  */
 
 /*
@@ -66,7 +66,7 @@
 
 #define	_RPCSVC_CLOSEDOWN 120
 #ifndef lint
-static const char rcsid[] = "$Id: yp_main.c,v 1.4 1996/12/22 15:54:03 wpaul Exp $";
+static const char rcsid[] = "$Id: yp_main.c,v 1.5 1996/12/24 07:52:52 wpaul Exp $";
 #endif /* not lint */
 int _rpcpmstart;		/* Started by a port monitor ? */
 static int _rpcfdtype;
@@ -122,8 +122,7 @@ yp_svc_run()
 		readfds = svc_fds;
 #endif /* def FD_SETSIZE */
 
-		if (yp_dnsq_pending())
-			FD_SET(resfd, &readfds);
+		FD_SET(resfd, &readfds);
 
 		switch (select(fd_setsize, &readfds, NULL, NULL,
 			       &timeout)) {
diff --git a/usr.sbin/ypserv/yp_server.c b/usr.sbin/ypserv/yp_server.c
index 32a8a2c..da1a73b 100644
--- a/usr.sbin/ypserv/yp_server.c
+++ b/usr.sbin/ypserv/yp_server.c
@@ -45,7 +45,7 @@
 #include <rpc/rpc.h>
 
 #ifndef lint
-static const char rcsid[] = "$Id: yp_server.c,v 1.2 1996/12/22 06:57:55 wpaul Exp $";
+static const char rcsid[] = "$Id: yp_server.c,v 1.3 1996/12/24 18:43:53 wpaul Exp $";
 #endif /* not lint */
 
 int forked = 0;
@@ -169,10 +169,10 @@ ypproc_match_2_svc(ypreq_key *argp, struct svc_req *rqstp)
 				  argp->key.keydat_val);
 
 		if (!strcmp(argp->map, "hosts.byname"))
-			result.stat = yp_async_lookup_name(rqstp->rq_xprt,
+			result.stat = yp_async_lookup_name(rqstp,
 					(char *)argp->key.keydat_val);
 		else if (!strcmp(argp->map, "hosts.byaddr"))
-			result.stat = yp_async_lookup_addr(rqstp->rq_xprt,
+			result.stat = yp_async_lookup_addr(rqstp,
 					(char *)argp->key.keydat_val);
 
 		if (result.stat == YP_TRUE)