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rxrpc: Fix exclusive connection handling

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"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>
This commit is contained in:
David Howells
2016-04-04 14:00:37 +01:00
parent 85f32278bd
commit cc8feb8edd
5 changed files with 64 additions and 77 deletions
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105
net/rxrpc/conn_object.c
View File

@@ -328,71 +328,57 @@ static int rxrpc_connect_exclusive(struct rxrpc_sock *rx,
_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 @@ found_channel:
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 @@ int rxrpc_connect_call(struct rxrpc_sock *rx,
_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);