rxrpc: Simplify connect() implementation and simplify sendmsg() op

Simplify the RxRPC connect() implementation.  It will just note the
destination address it is given, and if a sendmsg() comes along with no
address, this will be assigned as the address.  No transport struct will be
held internally, which will allow us to remove this later.

Simplify sendmsg() also.  Whilst a call is active, userspace refers to it
by a private unique user ID specified in a control message.  When sendmsg()
sees a user ID that doesn't map to an extant call, it creates a new call
for that user ID and attempts to add it.  If, when we try to add it, the
user ID is now registered, we now reject the message with -EEXIST.  We
should never see this situation unless two threads are racing, trying to
create a call with the same ID - which would be an error.

It also isn't required to provide sendmsg() with an address - provided the
control message data holds a user ID that maps to a currently active call.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 87 insertions, 99 deletions

diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index ea619535f0ed..2e3c4064e29c 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -32,13 +32,13 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 /*
  * extract control messages from the sendmsg() control buffer
  */
-static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
+static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 			      unsigned long *user_call_ID,
 			      enum rxrpc_command *command,
-			      u32 *abort_code,
-			      bool server)
+			      u32 *abort_code)
 {
 	struct cmsghdr *cmsg;
+	bool got_user_ID = false;
 	int len;
 
 	*command = RXRPC_CMD_SEND_DATA;
@@ -70,6 +70,7 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 					CMSG_DATA(cmsg);
 			}
 			_debug("User Call ID %lx", *user_call_ID);
+			got_user_ID = true;
 			break;
 
 		case RXRPC_ABORT:
@@ -90,8 +91,6 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 			*command = RXRPC_CMD_ACCEPT;
 			if (len != 0)
 				return -EINVAL;
-			if (!server)
-				return -EISCONN;
 			break;
 
 		default:
@@ -99,6 +98,8 @@ static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 		}
 	}
 
+	if (!got_user_ID)
+		return -EINVAL;
 	_leave(" = 0");
 	return 0;
 }
@@ -126,55 +127,96 @@ static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
 }
 
 /*
+ * Create a new client call for sendmsg().
+ */
+static struct rxrpc_call *
+rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
+				  unsigned long user_call_ID)
+{
+	struct rxrpc_conn_bundle *bundle;
+	struct rxrpc_transport *trans;
+	struct rxrpc_call *call;
+	struct key *key;
+	long ret;
+
+	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+
+	_enter("");
+
+	if (!msg->msg_name)
+		return ERR_PTR(-EDESTADDRREQ);
+
+	trans = rxrpc_name_to_transport(rx, msg->msg_name, msg->msg_namelen, 0,
+					GFP_KERNEL);
+	if (IS_ERR(trans)) {
+		ret = PTR_ERR(trans);
+		goto out;
+	}
+
+	key = rx->key;
+	if (key && !rx->key->payload.data[0])
+		key = NULL;
+	bundle = rxrpc_get_bundle(rx, trans, key, srx->srx_service, GFP_KERNEL);
+	if (IS_ERR(bundle)) {
+		ret = PTR_ERR(bundle);
+		goto out_trans;
+	}
+
+	call = rxrpc_new_client_call(rx, trans, bundle, user_call_ID,
+				     GFP_KERNEL);
+	rxrpc_put_bundle(trans, bundle);
+	rxrpc_put_transport(trans);
+	if (IS_ERR(call)) {
+		ret = PTR_ERR(call);
+		goto out_trans;
+	}
+
+	_leave(" = %p\n", call);
+	return call;
+
+out_trans:
+	rxrpc_put_transport(trans);
+out:
+	_leave(" = %ld", ret);
+	return ERR_PTR(ret);
+}
+
+/*
  * send a message forming part of a client call through an RxRPC socket
  * - caller holds the socket locked
  * - the socket may be either a client socket or a server socket
  */
-int rxrpc_client_sendmsg(struct rxrpc_sock *rx, struct rxrpc_transport *trans,
-			 struct msghdr *msg, size_t len)
+int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 {
-	struct rxrpc_conn_bundle *bundle;
 	enum rxrpc_command cmd;
 	struct rxrpc_call *call;
 	unsigned long user_call_ID = 0;
-	struct key *key;
-	u16 service_id;
 	u32 abort_code = 0;
 	int ret;
 
 	_enter("");
 
-	ASSERT(trans != NULL);
-
-	ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
-				 false);
+	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code);
 	if (ret < 0)
 		return ret;
 
-	bundle = NULL;
-	if (trans) {
-		service_id = rx->srx.srx_service;
-		if (msg->msg_name) {
-			DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx,
-					 msg->msg_name);
-			service_id = srx->srx_service;
-		}
-		key = rx->key;
-		if (key && !rx->key->payload.data[0])
-			key = NULL;
-		bundle = rxrpc_get_bundle(rx, trans, key, service_id,
-					  GFP_KERNEL);
-		if (IS_ERR(bundle))
-			return PTR_ERR(bundle);
+	if (cmd == RXRPC_CMD_ACCEPT) {
+		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
+			return -EINVAL;
+		call = rxrpc_accept_call(rx, user_call_ID);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+		rxrpc_put_call(call);
+		return 0;
 	}
 
-	call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
-				     abort_code == 0, GFP_KERNEL);
-	if (trans)
-		rxrpc_put_bundle(trans, bundle);
-	if (IS_ERR(call)) {
-		_leave(" = %ld", PTR_ERR(call));
-		return PTR_ERR(call);
+	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
+	if (!call) {
+		if (cmd != RXRPC_CMD_SEND_DATA)
+			return -EBADSLT;
+		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
 	}
 
 	_debug("CALL %d USR %lx ST %d on CONN %p",
@@ -182,14 +224,21 @@ int rxrpc_client_sendmsg(struct rxrpc_sock *rx, struct rxrpc_transport *trans,
 
 	if (call->state >= RXRPC_CALL_COMPLETE) {
 		/* it's too late for this call */
-		ret = -ESHUTDOWN;
+		ret = -ECONNRESET;
 	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
 		rxrpc_send_abort(call, abort_code);
+		ret = 0;
 	} else if (cmd != RXRPC_CMD_SEND_DATA) {
 		ret = -EINVAL;
-	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
+	} else if (!call->in_clientflag &&
+		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 		/* request phase complete for this client call */
 		ret = -EPROTO;
+	} else if (call->in_clientflag &&
+		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		/* Reply phase not begun or not complete for service call. */
+		ret = -EPROTO;
 	} else {
 		ret = rxrpc_send_data(rx, call, msg, len);
 	}
@@ -268,67 +317,6 @@ void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
 EXPORT_SYMBOL(rxrpc_kernel_abort_call);
 
 /*
- * send a message through a server socket
- * - caller holds the socket locked
- */
-int rxrpc_server_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
-{
-	enum rxrpc_command cmd;
-	struct rxrpc_call *call;
-	unsigned long user_call_ID = 0;
-	u32 abort_code = 0;
-	int ret;
-
-	_enter("");
-
-	ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
-				 true);
-	if (ret < 0)
-		return ret;
-
-	if (cmd == RXRPC_CMD_ACCEPT) {
-		call = rxrpc_accept_call(rx, user_call_ID);
-		if (IS_ERR(call))
-			return PTR_ERR(call);
-		rxrpc_put_call(call);
-		return 0;
-	}
-
-	call = rxrpc_find_server_call(rx, user_call_ID);
-	if (!call)
-		return -EBADSLT;
-	if (call->state >= RXRPC_CALL_COMPLETE) {
-		ret = -ESHUTDOWN;
-		goto out;
-	}
-
-	switch (cmd) {
-	case RXRPC_CMD_SEND_DATA:
-		if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
-		    call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
-		    call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
-			/* Tx phase not yet begun for this call */
-			ret = -EPROTO;
-			break;
-		}
-
-		ret = rxrpc_send_data(rx, call, msg, len);
-		break;
-
-	case RXRPC_CMD_SEND_ABORT:
-		rxrpc_send_abort(call, abort_code);
-		break;
-	default:
-		BUG();
-	}
-
-	out:
-	rxrpc_put_call(call);
-	_leave(" = %d", ret);
-	return ret;
-}
-
-/*
  * send a packet through the transport endpoint
  */
 int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)