SUNRPC: transport switch API for setting port number

 At some point, transport endpoint addresses will no longer be IPv4.  To hide
 the structure of the rpc_xprt's address field from ULPs and port mappers,
 add an API for setting the port number during an RPC bind operation.

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon
 with UDP and TCP.  NFSv2/3 and NFSv4 mounting should be carefully checked.
 Probably need to rig a server where certain services aren't running, or
 that returns an error for some typical operation.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 51f07c9a751b..3e8893001479 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -921,6 +921,18 @@ static void xs_udp_timer(struct rpc_task *task)
         xprt_adjust_cwnd(task, -ETIMEDOUT);
 }
 
+/**
+ * xs_set_port - reset the port number in the remote endpoint address
+ * @xprt: generic transport
+ * @port: new port number
+ *
+ */
+static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
+{
+        dprintk("RPC:      setting port for xprt %p to %u\n", xprt, port);
+        xprt->addr.sin_port = htons(port);
+}
+
 static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
 {
         struct sockaddr_in myaddr = {
@@ -1161,6 +1173,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
         .set_buffer_size        = xs_udp_set_buffer_size,
         .reserve_xprt           = xprt_reserve_xprt_cong,
         .release_xprt           = xprt_release_xprt_cong,
+        .set_port               = xs_set_port,
         .connect                = xs_connect,
         .buf_alloc              = rpc_malloc,
         .buf_free               = rpc_free,
@@ -1175,6 +1188,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
 static struct rpc_xprt_ops xs_tcp_ops = {
         .reserve_xprt           = xprt_reserve_xprt,
         .release_xprt           = xprt_release_xprt,
+        .set_port               = xs_set_port,
         .connect                = xs_connect,
         .buf_alloc              = rpc_malloc,
         .buf_free               = rpc_free,