rxrpc: Fix exclusive connection handling
"Exclusive connections" are meant to be used for a single client call and
then scrapped. The idea is to limit the use of the negotiated security
context. The current code, however, isn't doing this: it is instead
restricting the socket to a single virtual connection and doing all the
calls over that.
This is changed such that the socket no longer maintains a special virtual
connection over which it will do all the calls, but rather gets a new one
each time a new exclusive call is made.
Further, using a socket option for this is a poor choice. It should be
done on sendmsg with a control message marker instead so that calls can be
marked exclusive individually. To that end, add RXRPC_EXCLUSIVE_CALL
which, if passed to sendmsg() as a control message element, will cause the
call to be done on an single-use connection.
The socket option (RXRPC_EXCLUSIVE_CONNECTION) still exists and, if set,
will override any lack of RXRPC_EXCLUSIVE_CALL being specified so that
programs using the setsockopt() will appear to work the same.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index c6787b6..6164373 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -328,71 +328,57 @@
_enter("");
- conn = rx->conn;
+ conn = rxrpc_alloc_connection(gfp);
if (!conn) {
- /* not yet present - create a candidate for a new connection
- * and then redo the check */
- conn = rxrpc_alloc_connection(gfp);
- if (!conn) {
- _leave(" = -ENOMEM");
- return -ENOMEM;
- }
-
- conn->trans = trans;
- conn->bundle = NULL;
- conn->params = *cp;
- conn->proto.local = cp->local;
- conn->proto.epoch = rxrpc_epoch;
- conn->proto.cid = 0;
- conn->proto.in_clientflag = 0;
- conn->proto.family = cp->peer->srx.transport.family;
- conn->out_clientflag = RXRPC_CLIENT_INITIATED;
- conn->state = RXRPC_CONN_CLIENT;
- conn->avail_calls = RXRPC_MAXCALLS - 1;
-
- key_get(conn->params.key);
-
- ret = rxrpc_init_client_conn_security(conn);
- if (ret < 0) {
- key_put(conn->params.key);
- kfree(conn);
- _leave(" = %d [key]", ret);
- return ret;
- }
-
- write_lock_bh(&rxrpc_connection_lock);
- list_add_tail(&conn->link, &rxrpc_connections);
- write_unlock_bh(&rxrpc_connection_lock);
-
- spin_lock(&trans->client_lock);
- atomic_inc(&trans->usage);
-
- _net("CONNECT EXCL new %d on TRANS %d",
- conn->debug_id, conn->trans->debug_id);
-
- rxrpc_assign_connection_id(conn);
- rx->conn = conn;
- } else {
- spin_lock(&trans->client_lock);
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
}
- /* we've got a connection with a free channel and we can now attach the
- * call to it
- * - we're holding the transport's client lock
- * - we're holding a reference on the connection
- */
- for (chan = 0; chan < RXRPC_MAXCALLS; chan++)
- if (!conn->channels[chan])
- goto found_channel;
- goto no_free_channels;
+ conn->trans = trans;
+ conn->bundle = NULL;
+ conn->params = *cp;
+ conn->proto.local = cp->local;
+ conn->proto.epoch = rxrpc_epoch;
+ conn->proto.cid = 0;
+ conn->proto.in_clientflag = 0;
+ conn->proto.family = cp->peer->srx.transport.family;
+ conn->out_clientflag = RXRPC_CLIENT_INITIATED;
+ conn->state = RXRPC_CONN_CLIENT;
+ conn->avail_calls = RXRPC_MAXCALLS - 1;
-found_channel:
+ key_get(conn->params.key);
+
+ ret = rxrpc_init_client_conn_security(conn);
+ if (ret < 0) {
+ key_put(conn->params.key);
+ kfree(conn);
+ _leave(" = %d [key]", ret);
+ return ret;
+ }
+
+ write_lock_bh(&rxrpc_connection_lock);
+ list_add_tail(&conn->link, &rxrpc_connections);
+ write_unlock_bh(&rxrpc_connection_lock);
+
+ spin_lock(&trans->client_lock);
+ atomic_inc(&trans->usage);
+
+ _net("CONNECT EXCL new %d on TRANS %d",
+ conn->debug_id, conn->trans->debug_id);
+
+ rxrpc_assign_connection_id(conn);
+
+ /* Since no one else can use the connection, we just use the first
+ * channel.
+ */
+ chan = 0;
atomic_inc(&conn->usage);
conn->channels[chan] = call;
+ conn->call_counter = 1;
call->conn = conn;
call->channel = chan;
call->cid = conn->proto.cid | chan;
- call->call_id = ++conn->call_counter;
+ call->call_id = 1;
_net("CONNECT client on conn %d chan %d as call %x",
conn->debug_id, chan, call->call_id);
@@ -402,11 +388,6 @@
rxrpc_add_call_ID_to_conn(conn, call);
_leave(" = 0");
return 0;
-
-no_free_channels:
- spin_unlock(&trans->client_lock);
- _leave(" = -ENOSR");
- return -ENOSR;
}
/*
@@ -427,7 +408,7 @@
_enter("%p,%lx,", rx, call->user_call_ID);
- if (test_bit(RXRPC_SOCK_EXCLUSIVE_CONN, &rx->flags))
+ if (cp->exclusive)
return rxrpc_connect_exclusive(rx, cp, trans, call, gfp);
spin_lock(&trans->client_lock);