From b3156274ca01297b861e912175820e78c9ac4d7c Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 6 Oct 2016 08:11:49 +0100 Subject: [PATCH] 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 --- net/rxrpc/input.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) 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 @@ -938,6 +938,33 @@ static void rxrpc_input_call_packet(struct rxrpc_call *call, _leave(""); } +/* + * 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 @@ -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; -- 2.20.1