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>

3 files changed, 20 insertions, 3 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 7885b9621ce3..dd860128ceda 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -104,6 +104,7 @@ struct rpc_xprt_ops {
         void            (*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
         int             (*reserve_xprt)(struct rpc_task *task);
         void            (*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
+        void            (*set_port)(struct rpc_xprt *xprt, unsigned short port);
         void            (*connect)(struct rpc_task *task);
         void *          (*buf_alloc)(struct rpc_task *task, size_t size);
         void            (*buf_free)(struct rpc_task *task);
diff --git a/net/sunrpc/pmap_clnt.c b/net/sunrpc/pmap_clnt.c
index cad4568fbbe2..0935adb91b3c 100644
--- a/net/sunrpc/pmap_clnt.c
+++ b/net/sunrpc/pmap_clnt.c
@@ -131,10 +131,13 @@ static void
 pmap_getport_done(struct rpc_task *task)
 {
         struct rpc_clnt *clnt = task->tk_client;
+        struct rpc_xprt *xprt = task->tk_xprt;
         struct rpc_portmap *map = clnt->cl_pmap;
 
         dprintk("RPC: %4d pmap_getport_done(status %d, port %d)\n",
                         task->tk_pid, task->tk_status, clnt->cl_port);
+
+        xprt->ops->set_port(xprt, 0);
         if (task->tk_status < 0) {
                 /* Make the calling task exit with an error */
                 task->tk_action = rpc_exit_task;
@@ -142,9 +145,8 @@ pmap_getport_done(struct rpc_task *task)
                 /* Program not registered */
                 rpc_exit(task, -EACCES);
         } else {
-                /* byte-swap port number first */
+                xprt->ops->set_port(xprt, clnt->cl_port);
                 clnt->cl_port = htons(clnt->cl_port);
-                clnt->cl_xprt->addr.sin_port = clnt->cl_port;
         }
         spin_lock(&pmap_lock);
         map->pm_binding = 0;
@@ -205,7 +207,7 @@ pmap_create(char *hostname, struct sockaddr_in *srvaddr, int proto, int privileg
         xprt = xprt_create_proto(proto, srvaddr, NULL);
         if (IS_ERR(xprt))
                 return (struct rpc_clnt *)xprt;
-        xprt->addr.sin_port = htons(RPC_PMAP_PORT);
+        xprt->ops->set_port(xprt, RPC_PMAP_PORT);
         if (!privileged)
                 xprt->resvport = 0;
 
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,