gssd: Convert 'rdma' to 'tcp' protocol

The kernel NFS client specifies 'rdma' as the transport protocol for
NFS/RDMA mounts. This is a generic display token, probably not
something the kernel should lie about. The kernel uses it to form
NFSv4 client IDs, for example.

Until gssd can speak RPC-over-RDMA, convert 'rdma' to 'tcp' in
kernel gss upcalls.

This means that the Linux NFS client requires an NFS/TCP service on
an NFS/RDMA server when establishing a GSS context for proto=rdma
mount points. This is probably not an onerous requirement for the
time being.

Eventually user space support for RPC-over-RDMA might be introduced,
and gssd can use that for context establishment.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
index 2179e15..3b4d147 100644
--- a/utils/gssd/gssd.c
+++ b/utils/gssd/gssd.c
@@ -303,6 +303,22 @@ gssd_read_service_info(int dirfd, struct clnt_info *clp)
 		goto fail;
 	}
 
+	/*
+	 * The user space RPC library has no support for
+	 * RPC-over-RDMA at this time, so change 'rdma'
+	 * to 'tcp', and '20049' to '2049'.
+	 */
+	if (strcmp(protoname, "rdma") == 0) {
+		free(protoname);
+		protoname = strdup("tcp");
+		if (!protoname)
+			goto fail;
+		free(port);
+		port = strdup("2049");
+		if (!port)
+			goto fail;
+	}
+
 	if (!gssd_addrstr_to_sockaddr((struct sockaddr *)&clp->addr,
 				 address, port ? port : ""))
 		goto fail;