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

15 files changed, 180 insertions, 51 deletions

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index cd34ffb..0c4dc4a 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/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;
 		}
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 067dbb3..e9b536c 100644
--- a/net/rxrpc/ar-internal.h
+++ b/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 *);
 
 /*
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index a8515b0..0d4d84e 100644
--- a/net/rxrpc/call_accept.c
+++ b/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,
diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c
index c86f320..dd8bb91 100644
--- a/net/rxrpc/conn_client.c
+++ b/net/rxrpc/conn_client.c
@@ -36,12 +36,15 @@
  *
  *	rxrpc_nr_active_client_conns is held incremented also.
  *
- *  (4) CULLED - The connection got summarily culled to try and free up
+ *  (4) UPGRADE - As for ACTIVE, but only one call may be in progress and is
+ *      being used to probe for service upgrade.
+ *
+ *  (5) CULLED - The connection got summarily culled to try and free up
  *      capacity.  Calls currently in progress on the connection are allowed to
  *      continue, but new calls will have to wait.  There can be no waiters in
  *      this state - the conn would have to go to the WAITING state instead.
  *
- *  (5) IDLE - The connection has no calls in progress upon it and must have
+ *  (6) IDLE - The connection has no calls in progress upon it and must have
  *      been exposed to the world (ie. the EXPOSED flag must be set).  When it
  *      expires, the EXPOSED flag is cleared and the connection transitions to
  *      the INACTIVE state.
@@ -184,10 +187,13 @@ rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
 	atomic_set(&conn->usage, 1);
 	if (cp->exclusive)
 		__set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
+	if (cp->upgrade)
+		__set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
 
 	conn->params		= *cp;
 	conn->out_clientflag	= RXRPC_CLIENT_INITIATED;
 	conn->state		= RXRPC_CONN_CLIENT;
+	conn->service_id	= cp->service_id;
 
 	ret = rxrpc_get_client_connection_id(conn, gfp);
 	if (ret < 0)
@@ -299,7 +305,8 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 #define cmp(X) ((long)conn->params.X - (long)cp->X)
 			diff = (cmp(peer) ?:
 				cmp(key) ?:
-				cmp(security_level));
+				cmp(security_level) ?:
+				cmp(upgrade));
 #undef cmp
 			if (diff < 0) {
 				p = p->rb_left;
@@ -343,6 +350,7 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 	if (cp->exclusive) {
 		call->conn = candidate;
 		call->security_ix = candidate->security_ix;
+		call->service_id = candidate->service_id;
 		_leave(" = 0 [exclusive %d]", candidate->debug_id);
 		return 0;
 	}
@@ -363,7 +371,8 @@ static int rxrpc_get_client_conn(struct rxrpc_call *call,
 #define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
 		diff = (cmp(peer) ?:
 			cmp(key) ?:
-			cmp(security_level));
+			cmp(security_level) ?:
+			cmp(upgrade));
 #undef cmp
 		if (diff < 0) {
 			pp = &(*pp)->rb_left;
@@ -392,6 +401,7 @@ candidate_published:
 	set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
 	call->conn = candidate;
 	call->security_ix = candidate->security_ix;
+	call->service_id = candidate->service_id;
 	spin_unlock(&local->client_conns_lock);
 	_leave(" = 0 [new %d]", candidate->debug_id);
 	return 0;
@@ -413,6 +423,7 @@ found_extant_conn:
 	spin_lock(&conn->channel_lock);
 	call->conn = conn;
 	call->security_ix = conn->security_ix;
+	call->service_id = conn->service_id;
 	list_add(&call->chan_wait_link, &conn->waiting_calls);
 	spin_unlock(&conn->channel_lock);
 	_leave(" = 0 [extant %d]", conn->debug_id);
@@ -432,8 +443,13 @@ error:
 static void rxrpc_activate_conn(struct rxrpc_net *rxnet,
 				struct rxrpc_connection *conn)
 {
-	trace_rxrpc_client(conn, -1, rxrpc_client_to_active);
-	conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
+	if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
+		trace_rxrpc_client(conn, -1, rxrpc_client_to_upgrade);
+		conn->cache_state = RXRPC_CONN_CLIENT_UPGRADE;
+	} else {
+		trace_rxrpc_client(conn, -1, rxrpc_client_to_active);
+		conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
+	}
 	rxnet->nr_active_client_conns++;
 	list_move_tail(&conn->cache_link, &rxnet->active_client_conns);
 }
@@ -457,7 +473,8 @@ static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet,
 
 	_enter("%d,%d", conn->debug_id, conn->cache_state);
 
-	if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE)
+	if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE ||
+	    conn->cache_state == RXRPC_CONN_CLIENT_UPGRADE)
 		goto out;
 
 	spin_lock(&rxnet->client_conn_cache_lock);
@@ -470,6 +487,7 @@ static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet,
 
 	switch (conn->cache_state) {
 	case RXRPC_CONN_CLIENT_ACTIVE:
+	case RXRPC_CONN_CLIENT_UPGRADE:
 	case RXRPC_CONN_CLIENT_WAITING:
 		break;
 
@@ -573,6 +591,9 @@ static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn)
 	case RXRPC_CONN_CLIENT_ACTIVE:
 		mask = RXRPC_ACTIVE_CHANS_MASK;
 		break;
+	case RXRPC_CONN_CLIENT_UPGRADE:
+		mask = 0x01;
+		break;
 	default:
 		return;
 	}
@@ -783,6 +804,15 @@ void rxrpc_disconnect_client_call(struct rxrpc_call *call)
 	spin_lock(&rxnet->client_conn_cache_lock);
 
 	switch (conn->cache_state) {
+	case RXRPC_CONN_CLIENT_UPGRADE:
+		/* Deal with termination of a service upgrade probe. */
+		if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
+			clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
+			trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
+			conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
+			rxrpc_activate_channels_locked(conn);
+		}
+		/* fall through */
 	case RXRPC_CONN_CLIENT_ACTIVE:
 		if (list_empty(&conn->waiting_calls)) {
 			rxrpc_deactivate_one_channel(conn, channel);
@@ -937,7 +967,8 @@ static void rxrpc_cull_active_client_conns(struct rxrpc_net *rxnet)
 		ASSERT(!list_empty(&rxnet->active_client_conns));
 		conn = list_entry(rxnet->active_client_conns.next,
 				  struct rxrpc_connection, cache_link);
-		ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_ACTIVE);
+		ASSERTIFCMP(conn->cache_state != RXRPC_CONN_CLIENT_ACTIVE,
+			    conn->cache_state, ==, RXRPC_CONN_CLIENT_UPGRADE);
 
 		if (list_empty(&conn->waiting_calls)) {
 			trace_rxrpc_client(conn, -1, rxrpc_client_to_culled);
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 46babcf..59a51a5 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -74,7 +74,7 @@ static void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
 	pkt.whdr.userStatus	= 0;
 	pkt.whdr.securityIndex	= conn->security_ix;
 	pkt.whdr._rsvd		= 0;
-	pkt.whdr.serviceId	= htons(chan->last_service_id);
+	pkt.whdr.serviceId	= htons(conn->service_id);
 
 	len = sizeof(pkt.whdr);
 	switch (chan->last_type) {
@@ -208,7 +208,7 @@ static int rxrpc_abort_connection(struct rxrpc_connection *conn,
 	whdr.userStatus	= 0;
 	whdr.securityIndex = conn->security_ix;
 	whdr._rsvd	= 0;
-	whdr.serviceId	= htons(conn->params.service_id);
+	whdr.serviceId	= htons(conn->service_id);
 
 	word		= htonl(conn->local_abort);
 
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index ade4d3d..5bb2551 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -167,7 +167,6 @@ void __rxrpc_disconnect_call(struct rxrpc_connection *conn,
 		 * through the channel, whilst disposing of the actual call record.
 		 */
 		trace_rxrpc_disconnect_call(call);
-		chan->last_service_id = call->service_id;
 		if (call->abort_code) {
 			chan->last_abort = call->abort_code;
 			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
diff --git a/net/rxrpc/conn_service.c b/net/rxrpc/conn_service.c
index edfc633..e60fcd2 100644
--- a/net/rxrpc/conn_service.c
+++ b/net/rxrpc/conn_service.c
@@ -150,7 +150,8 @@ struct rxrpc_connection *rxrpc_prealloc_service_connection(struct rxrpc_net *rxn
  * Set up an incoming connection.  This is called in BH context with the RCU
  * read lock held.
  */
-void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
+void rxrpc_new_incoming_connection(struct rxrpc_sock *rx,
+				   struct rxrpc_connection *conn,
 				   struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
@@ -160,6 +161,7 @@ void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
 	conn->proto.epoch	= sp->hdr.epoch;
 	conn->proto.cid		= sp->hdr.cid & RXRPC_CIDMASK;
 	conn->params.service_id	= sp->hdr.serviceId;
+	conn->service_id	= sp->hdr.serviceId;
 	conn->security_ix	= sp->hdr.securityIndex;
 	conn->out_clientflag	= 0;
 	if (conn->security_ix)
@@ -167,6 +169,14 @@ void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
 	else
 		conn->state	= RXRPC_CONN_SERVICE;
 
+	/* See if we should upgrade the service.  This can only happen on the
+	 * first packet on a new connection.  Once done, it applies to all
+	 * subsequent calls on that connection.
+	 */
+	if (sp->hdr.userStatus == RXRPC_USERSTATUS_SERVICE_UPGRADE &&
+	    conn->service_id == rx->service_upgrade.from)
+		conn->service_id = rx->service_upgrade.to;
+
 	/* Make the connection a target for incoming packets. */
 	rxrpc_publish_service_conn(conn->params.peer, conn);
 
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 45dba73..e56e23e 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -1142,6 +1142,13 @@ void rxrpc_data_ready(struct sock *udp_sk)
 		if (sp->hdr.securityIndex != conn->security_ix)
 			goto wrong_security;
 
+		if (sp->hdr.serviceId != conn->service_id) {
+			if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) ||
+			    conn->service_id != conn->params.service_id)
+				goto reupgrade;
+			conn->service_id = sp->hdr.serviceId;
+		}
+		
 		if (sp->hdr.callNumber == 0) {
 			/* Connection-level packet */
 			_debug("CONN %p {%d}", conn, conn->debug_id);
@@ -1194,6 +1201,9 @@ void rxrpc_data_ready(struct sock *udp_sk)
 				rxrpc_input_implicit_end_call(conn, call);
 			call = NULL;
 		}
+
+		if (call && sp->hdr.serviceId != call->service_id)
+			call->service_id = sp->hdr.serviceId;
 	} else {
 		skew = 0;
 		call = NULL;
@@ -1237,11 +1247,18 @@ wrong_security:
 	skb->priority = RXKADINCONSISTENCY;
 	goto post_abort;
 
+reupgrade:
+	rcu_read_unlock();
+	trace_rxrpc_abort("UPG", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
+			  RX_PROTOCOL_ERROR, EBADMSG);
+	goto protocol_error;
+
 bad_message_unlock:
 	rcu_read_unlock();
 bad_message:
 	trace_rxrpc_abort("BAD", sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
 			  RX_PROTOCOL_ERROR, EBADMSG);
+protocol_error:
 	skb->priority = RX_PROTOCOL_ERROR;
 post_abort:
 	skb->mark = RXRPC_SKB_MARK_LOCAL_ABORT;
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 17d79fd..38b99db 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -94,6 +94,7 @@ static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet,
 		rwlock_init(&local->services_lock);
 		local->debug_id = atomic_inc_return(&rxrpc_debug_id);
 		memcpy(&local->srx, srx, sizeof(*srx));
+		local->srx.srx_service = 0;
 	}
 
 	_leave(" = %p", local);
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 5dab1ff..5bd2d0f 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -292,6 +292,10 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 	whdr._rsvd	= htons(sp->hdr._rsvd);
 	whdr.serviceId	= htons(call->service_id);
 
+	if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) &&
+	    sp->hdr.seq == 1)
+		whdr.userStatus	= RXRPC_USERSTATUS_SERVICE_UPGRADE;
+
 	iov[0].iov_base = &whdr;
 	iov[0].iov_len = sizeof(whdr);
 	iov[1].iov_base = skb->head;
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index e92d840..7421656 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -190,7 +190,7 @@ print:
 		   " %s %08x %08x %08x\n",
 		   lbuff,
 		   rbuff,
-		   conn->params.service_id,
+		   conn->service_id,
 		   conn->proto.cid,
 		   rxrpc_conn_is_service(conn) ? "Svc" : "Clt",
 		   atomic_read(&conn->usage),
diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index f9caf3b..bdece21 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -522,8 +522,11 @@ try_again:
 	}
 
 	if (msg->msg_name) {
-		size_t len = sizeof(call->conn->params.peer->srx);
-		memcpy(msg->msg_name, &call->conn->params.peer->srx, len);
+		struct sockaddr_rxrpc *srx = msg->msg_name;
+		size_t len = sizeof(call->peer->srx);
+
+		memcpy(msg->msg_name, &call->peer->srx, len);
+		srx->srx_service = call->service_id;
 		msg->msg_namelen = len;
 	}
 
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 29fe20a..46d1a1f 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -649,7 +649,7 @@ static int rxkad_issue_challenge(struct rxrpc_connection *conn)
 	whdr.userStatus	= 0;
 	whdr.securityIndex = conn->security_ix;
 	whdr._rsvd	= 0;
-	whdr.serviceId	= htons(conn->params.service_id);
+	whdr.serviceId	= htons(conn->service_id);
 
 	iov[0].iov_base	= &whdr;
 	iov[0].iov_len	= sizeof(whdr);
diff --git a/net/rxrpc/security.c b/net/rxrpc/security.c
index 7d921e5..e9f4283 100644
--- a/net/rxrpc/security.c
+++ b/net/rxrpc/security.c
@@ -121,7 +121,7 @@ int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
 
 	_enter("");
 
-	sprintf(kdesc, "%u:%u", conn->params.service_id, conn->security_ix);
+	sprintf(kdesc, "%u:%u", conn->service_id, conn->security_ix);
 
 	sec = rxrpc_security_lookup(conn->security_ix);
 	if (!sec) {
@@ -133,7 +133,8 @@ int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
 	read_lock(&local->services_lock);
 	rx = rcu_dereference_protected(local->service,
 				       lockdep_is_held(&local->services_lock));
-	if (rx && rx->srx.srx_service == conn->params.service_id)
+	if (rx && (rx->srx.srx_service == conn->service_id ||
+		   rx->second_service == conn->service_id))
 		goto found_service;
 
 	/* the service appears to have died */
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 96ffa5d..5a4801e 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -366,7 +366,8 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 			      unsigned long *user_call_ID,
 			      enum rxrpc_command *command,
 			      u32 *abort_code,
-			      bool *_exclusive)
+			      bool *_exclusive,
+			      bool *_upgrade)
 {
 	struct cmsghdr *cmsg;
 	bool got_user_ID = false;
@@ -429,6 +430,13 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
 			if (len != 0)
 				return -EINVAL;
 			break;
+
+		case RXRPC_UPGRADE_SERVICE:
+			*_upgrade = true;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
 		default:
 			return -EINVAL;
 		}
@@ -447,7 +455,8 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
  */
 static struct rxrpc_call *
 rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
-				  unsigned long user_call_ID, bool exclusive)
+				  unsigned long user_call_ID, bool exclusive,
+				  bool upgrade)
 	__releases(&rx->sk.sk_lock.slock)
 {
 	struct rxrpc_conn_parameters cp;
@@ -472,6 +481,7 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 	cp.key			= rx->key;
 	cp.security_level	= rx->min_sec_level;
 	cp.exclusive		= rx->exclusive | exclusive;
+	cp.upgrade		= upgrade;
 	cp.service_id		= srx->srx_service;
 	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
 	/* The socket is now unlocked */
@@ -493,13 +503,14 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 	struct rxrpc_call *call;
 	unsigned long user_call_ID = 0;
 	bool exclusive = false;
+	bool upgrade = true;
 	u32 abort_code = 0;
 	int ret;
 
 	_enter("");
 
 	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
-				 &exclusive);
+				 &exclusive, &upgrade);
 	if (ret < 0)
 		goto error_release_sock;
 
@@ -521,7 +532,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		if (cmd != RXRPC_CMD_SEND_DATA)
 			goto error_release_sock;
 		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
-							 exclusive);
+							 exclusive, upgrade);
 		/* The socket is now unlocked... */
 		if (IS_ERR(call))
 			return PTR_ERR(call);