[PATCH v3] rpc.nfsd: Squelch DNS errors when using the --host option

[Chuck Lever <chuck.lever@oracle.com>]

Sean Elble <elbles@sessys.com> says:
> [rpc.nfsd --host] throws an error/warning (where nfs-server is
> defined in /etc/hosts for the IPv4 address of the interface I wish
> for TCP port 2049 to be opened on):
>
>  rpc.nfsd: unable to resolve nfs-server:nfs to inet6 address: Name
>  or service not known

I think we can simplify the use of getaddrinfo(3) so that only one
call is needed to gather both IPv4 and IPv6 addresses. The call
should fail, and an error should be reported, only when there are
_no_ addresses bound to a hostname.

Reported-by: Sean Elble <elbles@sessys.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---


Here is version 3. This version addresses both Jeff's and Kinglong's
review comments. It has passed basic testing.


 utils/nfsd/nfsd.c   |   70 ++-------------------------------------------------
 utils/nfsd/nfssvc.c |   47 ++++++++++++++++++----------------
 utils/nfsd/nfssvc.h |    2 +
 3 files changed, 29 insertions(+), 90 deletions(-)

diff --git a/utils/nfsd/nfsd.c b/utils/nfsd/nfsd.c
index 201bb13..2165744 100644
--- a/utils/nfsd/nfsd.c
+++ b/utils/nfsd/nfsd.c
@@ -52,50 +52,6 @@ static struct option longopts[] =
 	{ NULL, 0, 0, 0 }
 };
 
-/* given a family and ctlbits, disable any that aren't listed in netconfig */
-#ifdef HAVE_LIBTIRPC
-static void
-nfsd_enable_protos(unsigned int *proto4, unsigned int *proto6)
-{
-	struct netconfig *nconf;
-	unsigned int *famproto;
-	void *handle;
-
-	xlog(D_GENERAL, "Checking netconfig for visible protocols.");
-
-	handle = setnetconfig();
-	while((nconf = getnetconfig(handle))) {
-		if (!(nconf->nc_flag & NC_VISIBLE))
-			continue;
-
-		if (!strcmp(nconf->nc_protofmly, NC_INET))
-			famproto = proto4;
-		else if (!strcmp(nconf->nc_protofmly, NC_INET6))
-			famproto = proto6;
-		else
-			continue;
-
-		if (!strcmp(nconf->nc_proto, NC_TCP))
-			NFSCTL_TCPSET(*famproto);
-		else if (!strcmp(nconf->nc_proto, NC_UDP))
-			NFSCTL_UDPSET(*famproto);
-
-		xlog(D_GENERAL, "Enabling %s %s.", nconf->nc_protofmly,
-			nconf->nc_proto);
-	}
-	endnetconfig(handle);
-	return;
-}
-#else /* HAVE_LIBTIRPC */
-static void
-nfsd_enable_protos(unsigned int *proto4, unsigned int *proto6)
-{
-	/* Enable all IPv4 protocols if no TIRPC support */
-	*proto4 = NFSCTL_ALLBITS;
-	*proto6 = 0;
-}
-#endif /* HAVE_LIBTIRPC */
-
 int
 main(int argc, char **argv)
 {
@@ -108,8 +64,6 @@ main(int argc, char **argv)
 	unsigned int minorversset = 0;
 	unsigned int versbits = NFSCTL_VERDEFAULT;
 	unsigned int protobits = NFSCTL_ALLBITS;
-	unsigned int proto4 = 0;
-	unsigned int proto6 = 0;
 	int grace = -1;
 	int lease = -1;
 
@@ -278,18 +232,6 @@ main(int argc, char **argv)
 
 	xlog_open(progname);
 
-	nfsd_enable_protos(&proto4, &proto6);
-
-	if (!NFSCTL_TCPISSET(protobits)) {
-		NFSCTL_TCPUNSET(proto4);
-		NFSCTL_TCPUNSET(proto6);
-	}
-
-	if (!NFSCTL_UDPISSET(protobits)) {
-		NFSCTL_UDPUNSET(proto4);
-		NFSCTL_UDPUNSET(proto6);
-	}
-
 	/* make sure that at least one version is enabled */
 	found_one = 0;
 	for (c = NFSD_MINVERS; c <= NFSD_MAXVERS; c++) {
@@ -302,8 +244,7 @@ main(int argc, char **argv)
 	}
 
 	if (NFSCTL_VERISSET(versbits, 4) &&
-	    !NFSCTL_TCPISSET(proto4) &&
-	    !NFSCTL_TCPISSET(proto6)) {
+	    !NFSCTL_TCPISSET(protobits)) {
 		xlog(L_ERROR, "version 4 requires the TCP protocol");
 		exit(1);
 	}
@@ -337,15 +278,10 @@ main(int argc, char **argv)
 
 	i = 0;
 	do {
-		error = nfssvc_set_sockets(AF_INET, proto4, haddr[i], port);
-		if (!error)
-			socket_up = 1;
-#ifdef IPV6_SUPPORTED
-		error = nfssvc_set_sockets(AF_INET6, proto6, haddr[i], port);
+		error = nfssvc_set_sockets(protobits, haddr[i], port);
 		if (!error)
 			socket_up = 1;
-#endif /* IPV6_SUPPORTED */
-	} while (++i < hcounter); 
+	} while (++i < hcounter);
 
 	if (rdma_port) {
 		error = nfssvc_set_rdmaport(rdma_port);
diff --git a/utils/nfsd/nfssvc.c b/utils/nfsd/nfssvc.c
index 027e5ac..a2b11d8 100644
--- a/utils/nfsd/nfssvc.c
+++ b/utils/nfsd/nfssvc.c
@@ -24,6 +24,7 @@
 
 #include "nfslib.h"
 #include "xlog.h"
+#include "nfssvc.h"
 
 #ifndef NFSD_FS_DIR
 #define NFSD_FS_DIR	  "/proc/fs/nfsd"
@@ -124,22 +125,6 @@ nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
 	if (fd < 0)
 		return 0;
 
-	switch(hints->ai_family) {
-	case AF_INET:
-		family = "inet";
-		break;
-#ifdef IPV6_SUPPORTED
-	case AF_INET6:
-		family = "inet6";
-		break;
-#endif /* IPV6_SUPPORTED */
-	default:
-		xlog(L_ERROR, "Unknown address family specified: %d\n",
-				hints->ai_family);
-		rc = EAFNOSUPPORT;
-		goto error;
-	}
-
 	rc = getaddrinfo(node, port, hints, &addrhead);
 	if (rc == EAI_NONAME && !strcmp(port, "nfs")) {
 		snprintf(buf, sizeof(buf), "%d", NFS_PORT);
@@ -147,10 +132,10 @@ nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
 	}
 
 	if (rc != 0) {
-		xlog(L_ERROR, "unable to resolve %s:%s to %s address: "
-				"%s", node ? node : "ANYADDR", port, family,
-				rc == EAI_SYSTEM ? strerror(errno) :
-					gai_strerror(rc));
+		xlog(L_ERROR, "unable to resolve %s:%s: %s",
+			node ? node : "ANYADDR", port,
+			rc == EAI_SYSTEM ? strerror(errno) :
+				gai_strerror(rc));
 		goto error;
 	}
 
@@ -169,6 +154,20 @@ nfssvc_setfds(const struct addrinfo *hints, const char *node, const char *port)
 			continue;
 		}
 
+		switch(addr->ai_addr->sa_family) {
+		case AF_INET:
+			family = "AF_INET";
+			break;
+#ifdef IPV6_SUPPORTED
+		case AF_INET6:
+			family = "AF_INET6";
+			break;
+#endif /* IPV6_SUPPORTED */
+		default:
+			addr = addr->ai_next;
+			continue;
+		}
+
 		xlog(D_GENERAL, "Creating %s %s socket.", family, proto);
 
 		/* open socket and prepare to hand it off to kernel */
@@ -252,12 +251,16 @@ error:
 }
 
 int
-nfssvc_set_sockets(const int family, const unsigned int protobits,
+nfssvc_set_sockets(const unsigned int protobits,
 		   const char *host, const char *port)
 {
 	struct addrinfo hints = { .ai_flags = AI_PASSIVE };
 
-	hints.ai_family = family;
+#ifdef IPV6_SUPPORTED
+	hints.ai_family = AF_UNSPEC;
+#else  /* IPV6_SUPPORTED */
+	hints.ai_family = AF_INET;
+#endif /* IPV6_SUPPORTED */
 
 	if (!NFSCTL_ANYPROTO(protobits))
 		return EPROTOTYPE;
diff --git a/utils/nfsd/nfssvc.h b/utils/nfsd/nfssvc.h
index fbb89b2..7d70f0d 100644
--- a/utils/nfsd/nfssvc.h
+++ b/utils/nfsd/nfssvc.h
@@ -22,7 +22,7 @@
 
 void	nfssvc_mount_nfsdfs(char *progname);
 int	nfssvc_inuse(void);
-int	nfssvc_set_sockets(const int family, const unsigned int protobits,
+int	nfssvc_set_sockets(const unsigned int protobits,
 			   const char *host, const char *port);
 void	nfssvc_set_time(const char *type, const int seconds);
 int	nfssvc_set_rdmaport(const char *port);