From: Neil Brown <neilb@suse.de>
Date: Tue, 13 Mar 2007 03:39:49 +0000 (+1100)
Subject: Restore use of un-connected socket for UDP mount requests.
X-Git-Tag: nfs-utils-1-1-0-rc1~87
X-Git-Url: https://git.decadent.org.uk/gitweb/?p=nfs-utils.git;a=commitdiff_plain;h=7f9343a38c031d9cc61a6bc7e06df519b16d1293

Restore use of un-connected socket for UDP mount requests.

When connecting to an NFSv4 server we need to find out IP address
as it would be seen by the server, to register an address for
callbacks.
This is most easily done by connecting the socket to the
servers address and then getting the address of our endpoint.

However with a connected UDP socket, replies that come from a
different IP address - as can happen with non-Linux multi-homed
servers - will be rejected.

So if we connected our UDP socket, we need to be sure to
disconnect it before using it.

This patch adds an option to get_socket to say if we want it
connected or not and, in the case where we do, we disconnect
a UDP socket after the connection information has been used.

Also clean up the error handling in clnt_ping which was getting
clumsy.
---

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..29dbb82 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;
@@ -129,20 +129,37 @@ 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);
-	if (sock == RPC_ANYSOCK && errno == ETIMEDOUT) {
-		/*
-		 * TCP timeout. Bubble up the error to see 
-		 * how it should be handled.
-		 */
-		rpc_createerr.cf_stat = RPC_TIMEDOUT;
-		goto out_bad;
+	sock = get_socket(saddr, prot, FALSE, TRUE);
+	if (sock == RPC_ANYSOCK) {
+		if (errno == ETIMEDOUT) {
+			/*
+			 * TCP timeout. Bubble up the error to see 
+			 * how it should be handled.
+			 */
+			rpc_createerr.cf_stat = RPC_TIMEDOUT;
+		}
+		return 0;
+	}
+
+	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);
@@ -151,11 +168,11 @@ clnt_ping(struct sockaddr_in *saddr, const u_long prog, const u_long vers,
 		clnt = clnttcp_create(saddr, prog, vers, &sock,
 				      RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 		break;
-	default:
-		goto out_bad;
 	}
-	if (!clnt)
-		goto out_bad;
+	if (!clnt) {
+		close(sock);
+		return 0;
+	}
 	memset(&clnt_res, 0, sizeof(clnt_res));
 	stat = clnt_call(clnt, NULLPROC,
 			 (xdrproc_t)xdr_void, (caddr_t)NULL,
@@ -166,21 +183,12 @@ 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;
-
- out_bad:
-	return 0;
+	else
+		return 0;
 }
 
 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
@@ -191,7 +199,7 @@ 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 b78daad..2ad7b35 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: