SUNRPC: Plumb an API for setting transport layer security

Add an initial set of policies along with fields for upper layers to
pass the requested policy down to the transport layer.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/sunrpc/clnt.h

@@ -58,6 +58,7 @@ struct rpc_clnt {
 				cl_noretranstimeo: 1,/* No retransmit timeouts */
 				cl_autobind : 1,/* use getport() */
 				cl_chatty   : 1;/* be verbose */
+	struct xprtsec_parms	cl_xprtsec;	/* transport security policy */
 
 	struct rpc_rtt *	cl_rtt;		/* RTO estimator data */
 	const struct rpc_timeout *cl_timeout;	/* Timeout strategy */
@@ -139,6 +140,7 @@ struct rpc_create_args {
 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
 	const struct cred	*cred;
 	unsigned int		max_connect;
+	struct xprtsec_parms	xprtsec;
 };
 
 struct rpc_add_xprt_test {

include/linux/sunrpc/xprt.h

@@ -129,6 +129,21 @@ struct rpc_rqst {
 #define rq_svec			rq_snd_buf.head
 #define rq_slen			rq_snd_buf.len
 
+/* RPC transport layer security policies */
+enum xprtsec_policies {
+	RPC_XPRTSEC_NONE = 0,
+	RPC_XPRTSEC_TLS_ANON,
+	RPC_XPRTSEC_TLS_X509,
+};
+
+struct xprtsec_parms {
+	enum xprtsec_policies	policy;
+
+	/* authentication material */
+	key_serial_t		cert_serial;
+	key_serial_t		privkey_serial;
+};
+
 struct rpc_xprt_ops {
 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
 	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
@@ -229,6 +244,7 @@ struct rpc_xprt {
 	 */
 	unsigned long		bind_timeout,
 				reestablish_timeout;
+	struct xprtsec_parms	xprtsec;
 	unsigned int		connect_cookie;	/* A cookie that gets bumped
 						   every time the transport
 						   is reconnected */
@@ -333,6 +349,7 @@ struct xprt_create {
 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
 	struct rpc_xprt_switch	*bc_xps;
 	unsigned int		flags;
+	struct xprtsec_parms	xprtsec;
 };
 
 struct xprt_class {

net/sunrpc/clnt.c

@@ -385,6 +385,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 	if (!clnt)
 		goto out_err;
 	clnt->cl_parent = parent ? : clnt;
+	clnt->cl_xprtsec = args->xprtsec;
 
 	err = rpc_alloc_clid(clnt);
 	if (err)
@@ -532,6 +533,7 @@ struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 		.addrlen = args->addrsize,
 		.servername = args->servername,
 		.bc_xprt = args->bc_xprt,
+		.xprtsec = args->xprtsec,
 	};
 	char servername[48];
 	struct rpc_clnt *clnt;
@@ -731,6 +733,7 @@ int rpc_switch_client_transport(struct rpc_clnt *clnt,
 	struct rpc_clnt *parent;
 	int err;
 
+	args->xprtsec = clnt->cl_xprtsec;
 	xprt = xprt_create_transport(args);
 	if (IS_ERR(xprt))
 		return PTR_ERR(xprt);
@@ -3050,6 +3053,7 @@ int rpc_clnt_add_xprt(struct rpc_clnt *clnt,
 
 	if (!xprtargs->ident)
 		xprtargs->ident = ident;
+	xprtargs->xprtsec = clnt->cl_xprtsec;
 	xprt = xprt_create_transport(xprtargs);
 	if (IS_ERR(xprt)) {
 		ret = PTR_ERR(xprt);