SUNRPC client: add interface for binding to a local address

In addition to binding to a local privileged port the NFS client should
allow binding to a specific local address. This is used by the server
for callbacks. The patch adds the necessary interface.

Signed-off-by: Frank van Maarseveen <frankvm@frankvm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

4 files changed, 19 insertions, 8 deletions

diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index c1b37972b0d5..c0d9d14983b3 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -98,6 +98,7 @@ struct rpc_create_args {
         int                     protocol;
         struct sockaddr         *address;
         size_t                  addrsize;
+        struct sockaddr         *saddress;
         struct rpc_timeout      *timeout;
         char                    *servername;
         struct rpc_program      *program;
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index ea828b09e4ad..d11cedd14f0f 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -198,6 +198,7 @@ struct rpc_xprt {
 
 struct rpc_xprtsock_create {
         int                     proto;          /* IPPROTO_UDP or IPPROTO_TCP */
+        struct sockaddr *       srcaddr;        /* optional local address */
         struct sockaddr *       dstaddr;        /* remote peer address */
         size_t                  addrlen;
         struct rpc_timeout *    timeout;        /* optional timeout parameters */
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 25bbf2d7f603..5d3fe7b22488 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -236,6 +236,7 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
         struct rpc_clnt *clnt;
         struct rpc_xprtsock_create xprtargs = {
                 .proto = args->protocol,
+                .srcaddr = args->saddress,
                 .dstaddr = args->address,
                 .addrlen = args->addrsize,
                 .timeout = args->timeout
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 6b7cea57651c..4ae7eed7f617 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -235,6 +235,7 @@ struct sock_xprt {
          * Connection of transports
          */
         struct delayed_work     connect_worker;
+        struct sockaddr_storage addr;
         unsigned short          port;
 
         /*
@@ -1145,31 +1146,36 @@ static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
         sap->sin_port = htons(port);
 }
 
-static int xs_bindresvport(struct sock_xprt *transport, struct socket *sock)
+static int xs_bind(struct sock_xprt *transport, struct socket *sock)
 {
         struct sockaddr_in myaddr = {
                 .sin_family = AF_INET,
         };
+        struct sockaddr_in *sa;
         int err;
         unsigned short port = transport->port;
 
+        if (!transport->xprt.resvport)
+                port = 0;
+        sa = (struct sockaddr_in *)&transport->addr;
+        myaddr.sin_addr = sa->sin_addr;
         do {
                 myaddr.sin_port = htons(port);
                 err = kernel_bind(sock, (struct sockaddr *) &myaddr,
                                                 sizeof(myaddr));
+                if (!transport->xprt.resvport)
+                        break;
                 if (err == 0) {
                         transport->port = port;
-                        dprintk("RPC:       xs_bindresvport bound to port %u\n",
-                                        port);
-                        return 0;
+                        break;
                 }
                 if (port <= xprt_min_resvport)
                         port = xprt_max_resvport;
                 else
                         port--;
         } while (err == -EADDRINUSE && port != transport->port);
-
-        dprintk("RPC:       can't bind to reserved port (%d).\n", -err);
+        dprintk("RPC:       xs_bind "NIPQUAD_FMT":%u: %s (%d)\n",
+                NIPQUAD(myaddr.sin_addr), port, err ? "failed" : "ok", err);
         return err;
 }
 
@@ -1228,7 +1234,7 @@ static void xs_udp_connect_worker(struct work_struct *work)
         }
         xs_reclassify_socket(sock);
 
-        if (xprt->resvport && xs_bindresvport(transport, sock) < 0) {
+        if (xs_bind(transport, sock)) {
                 sock_release(sock);
                 goto out;
         }
@@ -1315,7 +1321,7 @@ static void xs_tcp_connect_worker(struct work_struct *work)
                 }
                 xs_reclassify_socket(sock);
 
-                if (xprt->resvport && xs_bindresvport(transport, sock) < 0) {
+                if (xs_bind(transport, sock)) {
                         sock_release(sock);
                         goto out;
                 }
@@ -1531,6 +1537,8 @@ static struct rpc_xprt *xs_setup_xprt(struct rpc_xprtsock_create *args, unsigned
 
         memcpy(&xprt->addr, args->dstaddr, args->addrlen);
         xprt->addrlen = args->addrlen;
+        if (args->srcaddr)
+                memcpy(&new->addr, args->srcaddr, args->addrlen);
         new->port = xs_get_random_port();
 
         return xprt;