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authorDavid Howells <dhowells@redhat.com>2016-10-06 08:11:49 +0100
committerDavid Howells <dhowells@redhat.com>2016-10-06 08:11:49 +0100
commitb3156274ca01297b861e912175820e78c9ac4d7c (patch)
treeafa5a44c0f57db3ce8f442b50fd9460501d9a431 /net
parenta5af7e1fc69a46f29b977fd4b570e0ac414c2338 (diff)
downloadlinux-b3156274ca01297b861e912175820e78c9ac4d7c.tar.bz2
rxrpc: Partially handle OpenAFS's improper termination of calls
OpenAFS doesn't always correctly terminate client calls that it makes - this includes calls the OpenAFS servers make to the cache manager service. It should end the client call with either: (1) An ACK that has firstPacket set to one greater than the seq number of the reply DATA packet with the LAST_PACKET flag set (thereby hard-ACK'ing all packets). nAcks should be 0 and acks[] should be empty (ie. no soft-ACKs). (2) An ACKALL packet. OpenAFS, though, may send an ACK packet with firstPacket set to the last seq number or less and soft-ACKs listed for all packets up to and including the last DATA packet. The transmitter, however, is obliged to keep the call live and the soft-ACK'd DATA packets around until they're hard-ACK'd as the receiver is permitted to drop any merely soft-ACK'd packet and request retransmission by sending an ACK packet with a NACK in it. Further, OpenAFS will also terminate a client call by beginning the next client call on the same connection channel. This implicitly completes the previous call. This patch handles implicit ACK of a call on a channel by the reception of the first packet of the next call on that channel. If another call doesn't come along to implicitly ACK a call, then we have to time the call out. There are some bugs there that will be addressed in subsequent patches. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/rxrpc/input.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index a6da83f036d6..44fb8d893c7d 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -939,6 +939,33 @@ static void rxrpc_input_call_packet(struct rxrpc_call *call,
}
/*
+ * Handle a new call on a channel implicitly completing the preceding call on
+ * that channel.
+ *
+ * TODO: If callNumber > call_id + 1, renegotiate security.
+ */
+static void rxrpc_input_implicit_end_call(struct rxrpc_connection *conn,
+ struct rxrpc_call *call)
+{
+ switch (call->state) {
+ case RXRPC_CALL_SERVER_AWAIT_ACK:
+ rxrpc_call_completed(call);
+ break;
+ case RXRPC_CALL_COMPLETE:
+ break;
+ default:
+ if (rxrpc_abort_call("IMP", call, 0, RX_CALL_DEAD, ESHUTDOWN)) {
+ set_bit(RXRPC_CALL_EV_ABORT, &call->events);
+ rxrpc_queue_call(call);
+ }
+ break;
+ }
+
+ __rxrpc_disconnect_call(conn, call);
+ rxrpc_notify_socket(call);
+}
+
+/*
* post connection-level events to the connection
* - this includes challenges, responses, some aborts and call terminal packet
* retransmission.
@@ -1146,6 +1173,16 @@ void rxrpc_data_ready(struct sock *udp_sk)
}
call = rcu_dereference(chan->call);
+
+ if (sp->hdr.callNumber > chan->call_id) {
+ if (!(sp->hdr.flags & RXRPC_CLIENT_INITIATED)) {
+ rcu_read_unlock();
+ goto reject_packet;
+ }
+ if (call)
+ rxrpc_input_implicit_end_call(conn, call);
+ call = NULL;
+ }
} else {
skew = 0;
call = NULL;