Merge tag 'rxrpc-rewrite-20170606' of git://git.kernel.org/pub/scm/li…

…nux/kernel/git/dhowells/linux-fs

David Howells says:

====================
rxrpc: Support service upgrade

Here's a set of patches that allow AF_RXRPC to support the AuriStor service
upgrade facility.  This allows the server to change the service ID
requested to an upgraded service if the client requests it upon the
initiation of a connection.

This is used by the AuriStor AFS-compatible servers to implement IPv6
handling and improved facilities by providing improved volume location,
volume, protection, file and cache management services.  Note that certain
parts of the AFS protocol carry hard-coded IPv4 addresses.

The reason AuriStor does it this way is that probing the improved service
ID first will not incur an ABORT or any other response on some servers if
the server is not listening on it - and so one have to employ a timeout.

This is implemented in the server by allowing an AF_RXRPC server to call
bind() twice on a socket to allow it to listen on two service IDs and then
call setsockopt() to instruct the server to upgrade one into the other if
the client requests it (by setting userStatus to 1 on the first DATA packet
on a connection).  If the upgrade occurs, all further operations on that
connection are done with the new service ID.  AF_RXRPC has to handle this
automatically as connections are not exposed to userspace.

Clients can request this facility by setting an RXRPC_UPGRADE_SERVICE
command in the sendmsg() control buffer and then observing the resultant
service ID in the msg_addr returned by recvmsg().  This should only be used
to probe the service.  Clients should then use the returned service ID in
all subsequent communications with that server.  Note that the kernel will
not retain this information should the connection expire from its cache.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/rxrpc.txt

@@ -325,6 +325,8 @@ calls, to invoke certain actions and to report certain conditions.  These are:
 	RXRPC_LOCAL_ERROR	-rt error num	Local error encountered
 	RXRPC_NEW_CALL		-r- n/a		New call received
 	RXRPC_ACCEPT		s-- n/a		Accept new call
+	RXRPC_EXCLUSIVE_CALL	s-- n/a		Make an exclusive client call
+	RXRPC_UPGRADE_SERVICE	s-- n/a		Client call can be upgraded
 
 	(SRT = usable in Sendmsg / delivered by Recvmsg / Terminal message)
 
@@ -387,6 +389,23 @@ calls, to invoke certain actions and to report certain conditions.  These are:
      return error ENODATA.  If the user ID is already in use by another call,
      then error EBADSLT will be returned.
 
+ (*) RXRPC_EXCLUSIVE_CALL
+
+     This is used to indicate that a client call should be made on a one-off
+     connection.  The connection is discarded once the call has terminated.
+
+ (*) RXRPC_UPGRADE_SERVICE
+
+     This is used to make a client call to probe if the specified service ID
+     may be upgraded by the server.  The caller must check msg_name returned to
+     recvmsg() for the service ID actually in use.  The operation probed must
+     be one that takes the same arguments in both services.
+
+     Once this has been used to establish the upgrade capability (or lack
+     thereof) of the server, the service ID returned should be used for all
+     future communication to that server and RXRPC_UPGRADE_SERVICE should no
+     longer be set.
+
 
 ==============
 SOCKET OPTIONS
@@ -433,6 +452,13 @@ AF_RXRPC sockets support a few socket options at the SOL_RXRPC level:
 	 Encrypted checksum plus entire packet padded and encrypted, including
 	 actual packet length.
 
+ (*) RXRPC_UPGRADEABLE_SERVICE
+
+     This is used to indicate that a service socket with two bindings may
+     upgrade one bound service to the other if requested by the client.  optval
+     must point to an array of two unsigned short ints.  The first is the
+     service ID to upgrade from and the second the service ID to upgrade to.
+
 
 ========
 SECURITY
@@ -559,6 +585,17 @@ A client would issue an operation by:
      buffer instead, and MSG_EOR will be flagged to indicate the end of that
      call.
 
+A client may ask for a service ID it knows and ask that this be upgraded to a
+better service if one is available by supplying RXRPC_UPGRADE_SERVICE on the
+first sendmsg() of a call.  The client should then check srx_service in the
+msg_name filled in by recvmsg() when collecting the result.  srx_service will
+hold the same value as given to sendmsg() if the upgrade request was ignored by
+the service - otherwise it will be altered to indicate the service ID the
+server upgraded to.  Note that the upgraded service ID is chosen by the server.
+The caller has to wait until it sees the service ID in the reply before sending
+any more calls (further calls to the same destination will be blocked until the
+probe is concluded).
+
 
 ====================
 EXAMPLE SERVER USAGE
@@ -588,7 +625,7 @@ A server would be set up to accept operations in the following manner:
      The keyring can be manipulated after it has been given to the socket. This
      permits the server to add more keys, replace keys, etc. whilst it is live.
 
- (2) A local address must then be bound:
+ (3) A local address must then be bound:
 
 	struct sockaddr_rxrpc srx = {
 		.srx_family	= AF_RXRPC,
@@ -600,11 +637,26 @@ A server would be set up to accept operations in the following manner:
 	};
 	bind(server, &srx, sizeof(srx));
 
- (3) The server is then set to listen out for incoming calls:
+     More than one service ID may be bound to a socket, provided the transport
+     parameters are the same.  The limit is currently two.  To do this, bind()
+     should be called twice.
+
+ (4) If service upgrading is required, first two service IDs must have been
+     bound and then the following option must be set:
+
+	unsigned short service_ids[2] = { from_ID, to_ID };
+	setsockopt(server, SOL_RXRPC, RXRPC_UPGRADEABLE_SERVICE,
+		   service_ids, sizeof(service_ids));
+
+     This will automatically upgrade connections on service from_ID to service
+     to_ID if they request it.  This will be reflected in msg_name obtained
+     through recvmsg() when the request data is delivered to userspace.
+
+ (5) The server is then set to listen out for incoming calls:
 
 	listen(server, 100);
 
- (4) The kernel notifies the server of pending incoming connections by sending
+ (6) The kernel notifies the server of pending incoming connections by sending
      it a message for each.  This is received with recvmsg() on the server
      socket.  It has no data, and has a single dataless control message
      attached:
@@ -616,13 +668,13 @@ A server would be set up to accept operations in the following manner:
      the time it is accepted - in which case the first call still on the queue
      will be accepted.
 
- (5) The server then accepts the new call by issuing a sendmsg() with two
+ (7) The server then accepts the new call by issuing a sendmsg() with two
      pieces of control data and no actual data:
 
 	RXRPC_ACCEPT		- indicate connection acceptance
 	RXRPC_USER_CALL_ID	- specify user ID for this call
 
- (6) The first request data packet will then be posted to the server socket for
+ (8) The first request data packet will then be posted to the server socket for
      recvmsg() to pick up.  At that point, the RxRPC address for the call can
      be read from the address fields in the msghdr struct.
 
@@ -634,15 +686,15 @@ A server would be set up to accept operations in the following manner:
 
 	RXRPC_USER_CALL_ID	- specifies the user ID for this call
 
- (8) The reply data should then be posted to the server socket using a series
+ (9) The reply data should then be posted to the server socket using a series
      of sendmsg() calls, each with the following control messages attached:
 
 	RXRPC_USER_CALL_ID	- specifies the user ID for this call
 
      MSG_MORE should be set in msghdr::msg_flags on all but the last message
      for a particular call.
 
- (9) The final ACK from the client will be posted for retrieval by recvmsg()
+(10) The final ACK from the client will be posted for retrieval by recvmsg()
      when it is received.  It will take the form of a dataless message with two
      control messages attached:
 
@@ -652,7 +704,7 @@ A server would be set up to accept operations in the following manner:
      MSG_EOR will be flagged to indicate that this is the final message for
      this call.
 
-(10) Up to the point the final packet of reply data is sent, the call can be
+(11) Up to the point the final packet of reply data is sent, the call can be
      aborted by calling sendmsg() with a dataless message with the following
      control messages attached:
 

include/linux/rxrpc.h

@@ -37,6 +37,7 @@ struct sockaddr_rxrpc {
 #define RXRPC_SECURITY_KEYRING		2	/* [srvr] set ring of server security keys */
 #define RXRPC_EXCLUSIVE_CONNECTION	3	/* Deprecated; use RXRPC_EXCLUSIVE_CALL instead */
 #define RXRPC_MIN_SECURITY_LEVEL	4	/* minimum security level */
+#define RXRPC_UPGRADEABLE_SERVICE	5	/* Upgrade service[0] -> service[1] */
 
 /*
  * RxRPC control messages
@@ -53,6 +54,7 @@ struct sockaddr_rxrpc {
 #define RXRPC_NEW_CALL		8	/* -r: [Service] new incoming call notification */
 #define RXRPC_ACCEPT		9	/* s-: [Service] accept request */
 #define RXRPC_EXCLUSIVE_CALL	10	/* s-: Call should be on exclusive connection */
+#define RXRPC_UPGRADE_SERVICE	11	/* s-: Request service upgrade for client call */
 
 /*
  * RxRPC security levels

include/rxrpc/packet.h

@@ -58,6 +58,8 @@ struct rxrpc_wire_header {
 #define RXRPC_SLOW_START_OK	0x20		/* [ACK] slow start supported */
 
 	uint8_t		userStatus;	/* app-layer defined status */
+#define RXRPC_USERSTATUS_SERVICE_UPGRADE 0x01	/* AuriStor service upgrade request */
+
 	uint8_t		securityIndex;	/* security protocol ID */
 	union {
 		__be16	_rsvd;		/* reserved */

include/trace/events/rxrpc.h

@@ -233,6 +233,7 @@ enum rxrpc_congest_change {
 	EM(RXRPC_CONN_CLIENT_INACTIVE,		"Inac") \
 	EM(RXRPC_CONN_CLIENT_WAITING,		"Wait") \
 	EM(RXRPC_CONN_CLIENT_ACTIVE,		"Actv") \
+	EM(RXRPC_CONN_CLIENT_UPGRADE,		"Upgd") \
 	EM(RXRPC_CONN_CLIENT_CULLED,		"Cull") \
 	E_(RXRPC_CONN_CLIENT_IDLE,		"Idle") \
 

net/rxrpc/af_rxrpc.c

@@ -131,9 +131,8 @@ static int rxrpc_validate_address(struct rxrpc_sock *rx,
 static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 {
 	struct sockaddr_rxrpc *srx = (struct sockaddr_rxrpc *)saddr;
-	struct sock *sk = sock->sk;
 	struct rxrpc_local *local;
-	struct rxrpc_sock *rx = rxrpc_sk(sk);
+	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 	u16 service_id = srx->srx_service;
 	int ret;
 
@@ -145,31 +144,48 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
 
 	lock_sock(&rx->sk);
 
-	if (rx->sk.sk_state != RXRPC_UNBOUND) {
-		ret = -EINVAL;
-		goto error_unlock;
-	}
-
-	memcpy(&rx->srx, srx, sizeof(rx->srx));
+	switch (rx->sk.sk_state) {
+	case RXRPC_UNBOUND:
+		rx->srx = *srx;
+		local = rxrpc_lookup_local(sock_net(&rx->sk), &rx->srx);
+		if (IS_ERR(local)) {
+			ret = PTR_ERR(local);
+			goto error_unlock;
+		}
 
-	local = rxrpc_lookup_local(sock_net(sock->sk), &rx->srx);
-	if (IS_ERR(local)) {
-		ret = PTR_ERR(local);
-		goto error_unlock;
-	}
+		if (service_id) {
+			write_lock(&local->services_lock);
+			if (rcu_access_pointer(local->service))
+				goto service_in_use;
+			rx->local = local;
+			rcu_assign_pointer(local->service, rx);
+			write_unlock(&local->services_lock);
+
+			rx->sk.sk_state = RXRPC_SERVER_BOUND;
+		} else {
+			rx->local = local;
+			rx->sk.sk_state = RXRPC_CLIENT_BOUND;
+		}
+		break;
 
-	if (service_id) {
-		write_lock(&local->services_lock);
-		if (rcu_access_pointer(local->service))
-			goto service_in_use;
-		rx->local = local;
-		rcu_assign_pointer(local->service, rx);
-		write_unlock(&local->services_lock);
+	case RXRPC_SERVER_BOUND:
+		ret = -EINVAL;
+		if (service_id == 0)
+			goto error_unlock;
+		ret = -EADDRINUSE;
+		if (service_id == rx->srx.srx_service)
+			goto error_unlock;
+		ret = -EINVAL;
+		srx->srx_service = rx->srx.srx_service;
+		if (memcmp(srx, &rx->srx, sizeof(*srx)) != 0)
+			goto error_unlock;
+		rx->second_service = service_id;
+		rx->sk.sk_state = RXRPC_SERVER_BOUND2;
+		break;
 
-		rx->sk.sk_state = RXRPC_SERVER_BOUND;
-	} else {
-		rx->local = local;
-		rx->sk.sk_state = RXRPC_CLIENT_BOUND;
+	default:
+		ret = -EINVAL;
+		goto error_unlock;
 	}
 
 	release_sock(&rx->sk);
@@ -206,6 +222,7 @@ static int rxrpc_listen(struct socket *sock, int backlog)
 		ret = -EADDRNOTAVAIL;
 		break;
 	case RXRPC_SERVER_BOUND:
+	case RXRPC_SERVER_BOUND2:
 		ASSERT(rx->local != NULL);
 		max = READ_ONCE(rxrpc_max_backlog);
 		ret = -EINVAL;
@@ -473,6 +490,7 @@ static int rxrpc_setsockopt(struct socket *sock, int level, int optname,
 {
 	struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 	unsigned int min_sec_level;
+	u16 service_upgrade[2];
 	int ret;
 
 	_enter(",%d,%d,,%d", level, optname, optlen);
@@ -529,6 +547,28 @@ static int rxrpc_setsockopt(struct socket *sock, int level, int optname,
 			rx->min_sec_level = min_sec_level;
 			goto success;
 
+		case RXRPC_UPGRADEABLE_SERVICE:
+			ret = -EINVAL;
+			if (optlen != sizeof(service_upgrade) ||
+			    rx->service_upgrade.from != 0)
+				goto error;
+			ret = -EISCONN;
+			if (rx->sk.sk_state != RXRPC_SERVER_BOUND2)
+				goto error;
+			ret = -EFAULT;
+			if (copy_from_user(service_upgrade, optval,
+					   sizeof(service_upgrade)) != 0)
+				goto error;
+			ret = -EINVAL;
+			if ((service_upgrade[0] != rx->srx.srx_service ||
+			     service_upgrade[1] != rx->second_service) &&
+			    (service_upgrade[0] != rx->second_service ||
+			     service_upgrade[1] != rx->srx.srx_service))
+				goto error;
+			rx->service_upgrade.from = service_upgrade[0];
+			rx->service_upgrade.to = service_upgrade[1];
+			goto success;
+
 		default:
 			break;
 		}

net/rxrpc/ar-internal.h

@@ -61,6 +61,7 @@ enum {
 	RXRPC_CLIENT_UNBOUND,		/* Unbound socket used as client */
 	RXRPC_CLIENT_BOUND,		/* client local address bound */
 	RXRPC_SERVER_BOUND,		/* server local address bound */
+	RXRPC_SERVER_BOUND2,		/* second server local address bound */
 	RXRPC_SERVER_LISTENING,		/* server listening for connections */
 	RXRPC_SERVER_LISTEN_DISABLED,	/* server listening disabled */
 	RXRPC_CLOSE,			/* socket is being closed */
@@ -142,8 +143,14 @@ struct rxrpc_sock {
 	u32			min_sec_level;	/* minimum security level */
 #define RXRPC_SECURITY_MAX	RXRPC_SECURITY_ENCRYPT
 	bool			exclusive;	/* Exclusive connection for a client socket */
+	u16			second_service;	/* Additional service bound to the endpoint */
+	struct {
+		/* Service upgrade information */
+		u16		from;		/* Service ID to upgrade (if not 0) */
+		u16		to;		/* service ID to upgrade to */
+	} service_upgrade;
 	sa_family_t		family;		/* Protocol family created with */
-	struct sockaddr_rxrpc	srx;		/* local address */
+	struct sockaddr_rxrpc	srx;		/* Primary Service/local addresses */
 	struct sockaddr_rxrpc	connect_srx;	/* Default client address from connect() */
 };
 
@@ -313,6 +320,7 @@ struct rxrpc_conn_parameters {
 	struct rxrpc_peer	*peer;		/* Remote endpoint */
 	struct key		*key;		/* Security details */
 	bool			exclusive;	/* T if conn is exclusive */
+	bool			upgrade;	/* T if service ID can be upgraded */
 	u16			service_id;	/* Service ID for this connection */
 	u32			security_level;	/* Security level selected */
 };
@@ -327,6 +335,7 @@ enum rxrpc_conn_flag {
 	RXRPC_CONN_EXPOSED,		/* Conn has extra ref for exposure */
 	RXRPC_CONN_DONT_REUSE,		/* Don't reuse this connection */
 	RXRPC_CONN_COUNTED,		/* Counted by rxrpc_nr_client_conns */
+	RXRPC_CONN_PROBING_FOR_UPGRADE,	/* Probing for service upgrade */
 };
 
 /*
@@ -343,6 +352,7 @@ enum rxrpc_conn_cache_state {
 	RXRPC_CONN_CLIENT_INACTIVE,	/* Conn is not yet listed */
 	RXRPC_CONN_CLIENT_WAITING,	/* Conn is on wait list, waiting for capacity */
 	RXRPC_CONN_CLIENT_ACTIVE,	/* Conn is on active list, doing calls */
+	RXRPC_CONN_CLIENT_UPGRADE,	/* Conn is on active list, probing for upgrade */
 	RXRPC_CONN_CLIENT_CULLED,	/* Conn is culled and delisted, doing calls */
 	RXRPC_CONN_CLIENT_IDLE,		/* Conn is on idle list, doing mostly nothing */
 	RXRPC_CONN__NR_CACHE_STATES
@@ -386,7 +396,6 @@ struct rxrpc_connection {
 		u32			call_counter;	/* Call ID counter */
 		u32			last_call;	/* ID of last call */
 		u8			last_type;	/* Type of last packet */
-		u16			last_service_id;
 		union {
 			u32		last_seq;
 			u32		last_abort;
@@ -417,6 +426,7 @@ struct rxrpc_connection {
 	atomic_t		serial;		/* packet serial number counter */
 	unsigned int		hi_serial;	/* highest serial number received */
 	u32			security_nonce;	/* response re-use preventer */
+	u16			service_id;	/* Service ID, possibly upgraded */
 	u8			size_align;	/* data size alignment (for security) */
 	u8			security_size;	/* security header size */
 	u8			security_ix;	/* security type */
@@ -859,7 +869,8 @@ static inline void rxrpc_put_connection(struct rxrpc_connection *conn)
 struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *,
 						     struct sk_buff *);
 struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *, gfp_t);
-void rxrpc_new_incoming_connection(struct rxrpc_connection *, struct sk_buff *);
+void rxrpc_new_incoming_connection(struct rxrpc_sock *,
+				   struct rxrpc_connection *, struct sk_buff *);
 void rxrpc_unpublish_service_conn(struct rxrpc_connection *);
 
 /*

net/rxrpc/call_accept.c

@@ -296,7 +296,7 @@ static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 		conn->params.local = local;
 		conn->params.peer = peer;
 		rxrpc_see_connection(conn);
-		rxrpc_new_incoming_connection(conn, skb);
+		rxrpc_new_incoming_connection(rx, conn, skb);
 	} else {
 		rxrpc_get_connection(conn);
 	}
@@ -341,7 +341,8 @@ struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 
 	/* Get the socket providing the service */
 	rx = rcu_dereference(local->service);
-	if (rx && service_id == rx->srx.srx_service)
+	if (rx && (service_id == rx->srx.srx_service ||
+		   service_id == rx->second_service))
 		goto found_service;
 
 	trace_rxrpc_abort("INV", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,