rpc: pass target name down to rpc level on callbacks

The rpc client needs to know the principal that the setclientid was done
as, so it can tell gssd who to authenticate to.
Signed-off-by: NOlga Kornievskaia <aglo@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfsd/nfs4callback.c

@@ -384,6 +384,7 @@ static int do_probe_callback(void *data)
 		.version	= nfs_cb_version[1]->number,
 		.authflavor	= RPC_AUTH_UNIX, /* XXX: need AUTH_GSS... */
 		.flags		= (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
+		.client_name    = clp->cl_principal,
 	};
 	struct rpc_message msg = {
 		.rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
@@ -392,6 +393,11 @@ static int do_probe_callback(void *data)
 	struct rpc_clnt *client;
 	int status;
 
+	if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5)) {
+		status = nfserr_cb_path_down;
+		goto out_err;
+	}
+
 	/* Initialize address */
 	memset(&addr, 0, sizeof(addr));
 	addr.sin_family = AF_INET;

include/linux/sunrpc/clnt.h

@@ -58,6 +58,7 @@ struct rpc_clnt {
 	struct rpc_timeout	cl_timeout_default;
 	struct rpc_program *	cl_program;
 	char			cl_inline_name[32];
+	char			*cl_principal;	/* target to authenticate to */
 };
 
 /*
@@ -108,6 +109,7 @@ struct rpc_create_args {
 	u32			version;
 	rpc_authflavor_t	authflavor;
 	unsigned long		flags;
+	char			*client_name;
 };
 
 /* Values for "flags" field */

net/sunrpc/clnt.c

@@ -197,6 +197,12 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
 
 	clnt->cl_rtt = &clnt->cl_rtt_default;
 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
+	clnt->cl_principal = NULL;
+	if (args->client_name) {
+		clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
+		if (!clnt->cl_principal)
+			goto out_no_principal;
+	}
 
 	kref_init(&clnt->cl_kref);
 
@@ -226,6 +232,8 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
 		rpc_put_mount();
 	}
 out_no_path:
+	kfree(clnt->cl_principal);
+out_no_principal:
 	rpc_free_iostats(clnt->cl_metrics);
 out_no_stats:
 	if (clnt->cl_server != clnt->cl_inline_name)
@@ -354,6 +362,11 @@ rpc_clone_client(struct rpc_clnt *clnt)
 	new->cl_metrics = rpc_alloc_iostats(clnt);
 	if (new->cl_metrics == NULL)
 		goto out_no_stats;
+	if (clnt->cl_principal) {
+		new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
+		if (new->cl_principal == NULL)
+			goto out_no_principal;
+	}
 	kref_init(&new->cl_kref);
 	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 	if (err != 0)
@@ -366,6 +379,8 @@ rpc_clone_client(struct rpc_clnt *clnt)
 	rpciod_up();
 	return new;
 out_no_path:
+	kfree(new->cl_principal);
+out_no_principal:
 	rpc_free_iostats(new->cl_metrics);
 out_no_stats:
 	kfree(new);
@@ -417,6 +432,7 @@ rpc_free_client(struct kref *kref)
 out_free:
 	rpc_unregister_client(clnt);
 	rpc_free_iostats(clnt->cl_metrics);
+	kfree(clnt->cl_principal);
 	clnt->cl_metrics = NULL;
 	xprt_put(clnt->cl_xprt);
 	rpciod_down();