git: 032b04626b67 - main - rpcb_clnt.c: Do not force use of UDP

From: Rick Macklem <rmacklem_at_FreeBSD.org>
Date: Sun, 13 Nov 2022 20:17:10 UTC
The branch main has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=032b04626b671ec16deacd479569998b96c96142

commit 032b04626b671ec16deacd479569998b96c96142
Author:     Rick Macklem <rmacklem@FreeBSD.org>
AuthorDate: 2022-11-13 20:16:06 +0000
Commit:     Rick Macklem <rmacklem@FreeBSD.org>
CommitDate: 2022-11-13 20:16:06 +0000

    rpcb_clnt.c: Do not force use of UDP
    
    Without this patch, the code in the rpcbind client forces
    the use of UDP.  A comment notes that some rpcbind servers
    only support UDP.  This makes NFSv3 mounts to Azure servers
    impossible, since they require use of TCP for rpcbind.
    Since the comment is very old (imported from NetBSD in 2001)
    and I do not believe any UDP only rpcbind servers will
    still exist, this patch comments out the code that forces
    use of UDP, so that NFSv3 mounts to Azure servers can work.
    
    For an NFSv3 mount, the "udp" mount option will still
    make mount_nfs use UDP for rpcbind so that can be used
    as a workaround for any old NFSv3 server that only
    supports rpcbind over UDP (if any such server still exists).
    
    I asked if doing this change is appropriate on freebsd-fs@
    and I only got one reply (off list) that supported doing
    the change.
    
    PR:     267301
    MFC after:      1 month
---
 lib/libc/rpc/rpcb_clnt.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/libc/rpc/rpcb_clnt.c b/lib/libc/rpc/rpcb_clnt.c
index f39d99bfeee3..b44fd1c5e77b 100644
--- a/lib/libc/rpc/rpcb_clnt.c
+++ b/lib/libc/rpc/rpcb_clnt.c
@@ -741,6 +741,16 @@ __rpcb_findaddr_timed(rpcprog_t program, rpcvers_t version,
 		rpcvers_t pmapvers = 2;
 		struct pmap pmapparms;
 
+		/*
+		 * The comment below is now very old, having
+		 * been committed to FreeBSD during an import
+		 * from NetBSD in 2001.  I do not believe there
+		 * will still be any rpcbind servers that do
+		 * UDP only and, since Azure requires use of
+		 * TCP for NFSv3 mounts, comment this out
+		 * so that NFSv3 mounts on Azure can work.
+		 */
+#ifdef notnow
 		/*
 		 * Try UDP only - there are some portmappers out
 		 * there that use UDP only.
@@ -754,9 +764,9 @@ __rpcb_findaddr_timed(rpcprog_t program, rpcvers_t version,
 			}
 			client = getclnthandle(host, newnconf, &parms.r_addr);
 			freenetconfigent(newnconf);
-		} else {
+		} else
+#endif
 			client = getclnthandle(host, nconf, &parms.r_addr);
-		}
 		if (client == NULL)
 			return (NULL);