SUNRPC: rpc_create() default hostname should support AF_INET6 addresses

If the ULP doesn't pass a hostname string to rpc_create(), it manufactures
one based on the passed-in address.  Be smart enough to handle an AF_INET6
address properly in this case.

Move the default servername logic before the xprt_create_transport() call
to simplify error handling in rpc_create().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 27 insertions, 5 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index e0a5e47a1d4..3af35ab0e99 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -30,6 +30,7 @@
 #include <linux/smp_lock.h>
 #include <linux/utsname.h>
 #include <linux/workqueue.h>
+#include <linux/in6.h>
 
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/rpc_pipe_fs.h>
@@ -247,7 +248,7 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
                 .addrlen = args->addrsize,
                 .timeout = args->timeout
         };
-        char servername[20];
+        char servername[48];
 
         xprt = xprt_create_transport(&xprtargs);
         if (IS_ERR(xprt))
@@ -258,13 +259,34 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
          * up a string representation of the passed-in address.
          */
         if (args->servername == NULL) {
-                struct sockaddr_in *addr =
-                                        (struct sockaddr_in *) args->address;
-                snprintf(servername, sizeof(servername), NIPQUAD_FMT,
-                        NIPQUAD(addr->sin_addr.s_addr));
+                servername[0] = '\0';
+                switch (args->address->sa_family) {
+                case AF_INET: {
+                        struct sockaddr_in *sin =
+                                        (struct sockaddr_in *)args->address;
+                        snprintf(servername, sizeof(servername), NIPQUAD_FMT,
+                                 NIPQUAD(sin->sin_addr.s_addr));
+                        break;
+                }
+                case AF_INET6: {
+                        struct sockaddr_in6 *sin =
+                                        (struct sockaddr_in6 *)args->address;
+                        snprintf(servername, sizeof(servername), NIP6_FMT,
+                                 NIP6(sin->sin6_addr));
+                        break;
+                }
+                default:
+                        /* caller wants default server name, but
+                         * address family isn't recognized. */
+                        return ERR_PTR(-EINVAL);
+                }
                 args->servername = servername;
         }
 
+        xprt = xprt_create_transport(&xprtargs);
+        if (IS_ERR(xprt))
+                return (struct rpc_clnt *)xprt;
+
         /*
          * By default, kernel RPC client connects from a reserved port.
          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,