Re: [PATCH 09/11] nfs-utils: mount: Fixed mounts to multi-home servers

[Neil Brown <neilb@suse.de>]

On Tuesday February 27, jlayton@poochiereds.net wrote:
> 
> I know we saw this with Solaris servers in particular (it's been a 
> while, but I think I was testing against Solaris 8). The fedora BZ is 
> here if you want to see all the gory details:
> 
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=212471
> 
> I'm thinking we will have to deal with this situation, unfortunately, so 
> maybe disconnecting the socket after getting the address is the best thing?
> 
> -- Jeff

Thanks for the link... Looks like we do need to be very careful about
connecting UDP sockets.

This patch maybe?

NeilBrown


diff --git a/support/include/conn.h b/support/include/conn.h
index 1761dc4..11f16ab 100644
--- a/support/include/conn.h
+++ b/support/include/conn.h
@@ -35,7 +35,7 @@ int clnt_ping(struct sockaddr_in *, const u_long, const u_long, const u_int,
 	      struct sockaddr_in *);
 u_long nfsvers_to_mnt(const u_long);
 u_long mntvers_to_nfs(const u_long);
-int get_socket(struct sockaddr_in *, u_int, int);
+int get_socket(struct sockaddr_in *, u_int, int, int);
 CLIENT * mnt_openclnt(clnt_addr_t *, int *);
 void mnt_closeclnt(CLIENT *, int);
 
diff --git a/support/nfs/conn.c b/support/nfs/conn.c
index 89f7676..1020b47 100644
--- a/support/nfs/conn.c
+++ b/support/nfs/conn.c
@@ -49,7 +49,7 @@ u_long mntvers_to_nfs(const u_long vers)
  * RPC_ANYSOCK is returned which will cause 
  * the RPC code to create the socket instead. 
  */
-int get_socket(struct sockaddr_in *saddr, u_int p_prot, int resvp)
+int get_socket(struct sockaddr_in *saddr, u_int p_prot, int resvp, int conn)
 {
 	int so, cc, type;
 	struct sockaddr_in laddr;
@@ -98,7 +98,7 @@ int get_socket(struct sockaddr_in *saddr, u_int p_prot, int resvp)
 			return RPC_ANYSOCK;
 		}
 	}
-	if (type == SOCK_STREAM || type == SOCK_DGRAM) {
+	if (type == SOCK_STREAM || (conn && type == SOCK_DGRAM)) {
 		cc = connect(so, (struct sockaddr *)saddr, namelen);
 		if (cc < 0) {
 			rpc_createerr.cf_stat = RPC_SYSTEMERROR;
@@ -129,9 +129,10 @@ clnt_ping(struct sockaddr_in *saddr, const u_long prog, const u_long vers,
 	CLIENT *clnt=NULL;
 	int sock, stat;
 	static char clnt_res;
+	struct sockaddr dissolve;
 
 	rpc_createerr.cf_stat = stat = errno = 0;
-	sock = get_socket(saddr, prot, FALSE);
+	sock = get_socket(saddr, prot, FALSE, TRUE);
 	if (sock == RPC_ANYSOCK && errno == ETIMEDOUT) {
 		/*
 		 * TCP timeout. Bubble up the error to see 
@@ -141,8 +142,22 @@ clnt_ping(struct sockaddr_in *saddr, const u_long prog, const u_long vers,
 		goto out_bad;
 	}
 
+	if (caddr) {
+		/* Get the address of our end of this connection */
+		socklen_t len = sizeof(*caddr);
+		if (getsockname(sock, caddr, &len) != 0)
+			caddr->sin_family = 0;
+	}
+
 	switch(prot) {
 	case IPPROTO_UDP:
+		/* The socket is connected (so we could getsockname successfully),
+		 * but some servers on multi-homed hosts reply from
+		 * the wrong address, so if we stay connected, we lose the reply.
+		 */
+		dissolve.sa_family = AF_UNSPEC;
+		connect(sock, &dissolve, sizeof(dissolve));
+
 		clnt = clntudp_bufcreate(saddr, prog, vers,
 					 RETRY_TIMEOUT, &sock,
 					 RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
@@ -166,15 +181,7 @@ clnt_ping(struct sockaddr_in *saddr, const u_long prog, const u_long vers,
 		rpc_createerr.cf_stat = stat;
 	}
 	clnt_destroy(clnt);
-	if (sock != -1) {
-		if (caddr) {
-			/* Get the address of our end of this connection */
-			socklen_t len = sizeof(*caddr);
-			if (getsockname(sock, caddr, &len) != 0)
-				caddr->sin_family = 0;
-		}
-		close(sock);
-	}
+	close(sock);
 
 	if (stat == RPC_SUCCESS)
 		return 1;
@@ -191,7 +198,7 @@ CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
 
 	/* contact the mount daemon via TCP */
 	mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
-	*msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, TRUE);
+	*msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, TRUE, FALSE);
 
 	switch (mnt_pmap->pm_prot) {
 	case IPPROTO_UDP:
diff --git a/utils/mount/nfsmount.c b/utils/mount/nfsmount.c
index 507ccdb..0f66bdf 100644
--- a/utils/mount/nfsmount.c
+++ b/utils/mount/nfsmount.c
@@ -306,7 +306,7 @@ getport(
 	enum clnt_stat stat;
 
 	saddr->sin_port = htons (PMAPPORT);
-	socket = get_socket(saddr, prot, FALSE);
+	socket = get_socket(saddr, prot, FALSE, FALSE);
 
 	switch (prot) {
 	case IPPROTO_UDP:

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