SUNRPC: Add a TCP-with-TLS RPC transport class

Use the new TLS handshake API to enable the SunRPC client code
to request a TLS handshake. This implements support for RFC 9289,
only on TCP sockets.

Upper layers such as NFS use RPC-with-TLS to protect in-transit
traffic.

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

include/linux/sunrpc/xprt.h

@@ -200,6 +200,7 @@ enum xprt_transports {
 	XPRT_TRANSPORT_RDMA	= 256,
 	XPRT_TRANSPORT_BC_RDMA	= XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
 	XPRT_TRANSPORT_LOCAL	= 257,
+	XPRT_TRANSPORT_TCP_TLS	= 258,
 };
 
 struct rpc_sysfs_xprt;

include/linux/sunrpc/xprtsock.h

@@ -57,9 +57,11 @@ struct sock_xprt {
 	struct work_struct	error_worker;
 	struct work_struct	recv_worker;
 	struct mutex		recv_mutex;
+	struct completion	handshake_done;
 	struct sockaddr_storage	srcaddr;
 	unsigned short		srcport;
 	int			xprt_err;
+	struct rpc_clnt		*clnt;
 
 	/*
 	 * UDP socket buffer size parameters

include/trace/events/sunrpc.h

@@ -1525,6 +1525,50 @@ TRACE_EVENT(rpcb_unregister,
 	)
 );
 
+/**
+ ** RPC-over-TLS tracepoints
+ **/
+
+DECLARE_EVENT_CLASS(rpc_tls_class,
+	TP_PROTO(
+		const struct rpc_clnt *clnt,
+		const struct rpc_xprt *xprt
+	),
+
+	TP_ARGS(clnt, xprt),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, requested_policy)
+		__field(u32, version)
+		__string(servername, xprt->servername)
+		__string(progname, clnt->cl_program->name)
+	),
+
+	TP_fast_assign(
+		__entry->requested_policy = clnt->cl_xprtsec.policy;
+		__entry->version = clnt->cl_vers;
+		__assign_str(servername, xprt->servername);
+		__assign_str(progname, clnt->cl_program->name)
+	),
+
+	TP_printk("server=%s %sv%u requested_policy=%s",
+		__get_str(servername), __get_str(progname), __entry->version,
+		rpc_show_xprtsec_policy(__entry->requested_policy)
+	)
+);
+
+#define DEFINE_RPC_TLS_EVENT(name) \
+	DEFINE_EVENT(rpc_tls_class, rpc_tls_##name, \
+			TP_PROTO( \
+				const struct rpc_clnt *clnt, \
+				const struct rpc_xprt *xprt \
+			), \
+			TP_ARGS(clnt, xprt))
+
+DEFINE_RPC_TLS_EVENT(unavailable);
+DEFINE_RPC_TLS_EVENT(not_started);
+
+
 /* Record an xdr_buf containing a fully-formed RPC message */
 DECLARE_EVENT_CLASS(svc_xdr_msg_class,
 	TP_PROTO(

net/sunrpc/sysfs.c

@@ -239,6 +239,7 @@ static ssize_t rpc_sysfs_xprt_dstaddr_store(struct kobject *kobj,
 	if (!xprt)
 		return 0;
 	if (!(xprt->xprt_class->ident == XPRT_TRANSPORT_TCP ||
+	      xprt->xprt_class->ident == XPRT_TRANSPORT_TCP_TLS ||
 	      xprt->xprt_class->ident == XPRT_TRANSPORT_RDMA)) {
 		xprt_put(xprt);
 		return -EOPNOTSUPP;