path: root/net/rxrpc/call_object.c
diff options
authorDavid Howells <dhowells@redhat.com>2017-11-24 10:18:42 +0000
committerDavid Howells <dhowells@redhat.com>2017-11-24 10:18:42 +0000
commitbd1fdf8cfdf3fdbccd2b21c33ec649ebd7429af7 (patch)
treea4bd170409584ba9950b3193cd11213fb2552694 /net/rxrpc/call_object.c
parentbeb8e5e4f38cc3e4c2839cfc143e0312bf53d0e0 (diff)
rxrpc: Add a timeout for detecting lost ACKs/lost DATA
Add an extra timeout that is set/updated when we send a DATA packet that has the request-ack flag set. This allows us to detect if we don't get an ACK in response to the latest flagged packet. The ACK packet is adjudged to have been lost if it doesn't turn up within 2*RTT of the transmission. If the timeout occurs, we schedule the sending of a PING ACK to find out the state of the other side. If a new DATA packet is ready to go sooner, we cancel the sending of the ping and set the request-ack flag on that instead. If we get back a PING-RESPONSE ACK that indicates a lower tx_top than what we had at the time of the ping transmission, we adjudge all the DATA packets sent between the response tx_top and the ping-time tx_top to have been lost and retransmit immediately. Rather than sending a PING ACK, we could just pick a DATA packet and speculatively retransmit that with request-ack set. It should result in either a REQUESTED ACK or a DUPLICATE ACK which we can then use in lieu the a PING-RESPONSE ACK mentioned above. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net/rxrpc/call_object.c')
1 files changed, 1 insertions, 0 deletions
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index b305970a9b63..7ee3d6ce5aa2 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -197,6 +197,7 @@ static void rxrpc_start_call_timer(struct rxrpc_call *call)
unsigned long j = now + MAX_JIFFY_OFFSET;
call->ack_at = j;
+ call->ack_lost_at = j;
call->resend_at = j;
call->ping_at = j;
call->expect_rx_by = j;