A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-29 19:21:31 -04:00
Code Issues Projects Releases Packages Wiki Activity

rxrpc: Add keepalive for a call

Browse source 
We need to transmit a packet every so often to act as a keepalive for the
peer (which has a timeout from the last time it received a packet) and also
to prevent any intervening firewalls from closing the route.

Do this by resetting a timer every time we transmit a packet.  If the timer
ever expires, we transmit a PING ACK packet and thereby also elicit a PING
RESPONSE ACK from the other side - which prevents our last-rx timeout from
expiring.

The timer is set to 1/6 of the last-rx timeout so that we can detect the
other side going away if it misses 6 replies in a row.

This is particularly necessary for servers where the processing of the
service function may take a significant amount of time.

Signed-off-by: David Howells <[email protected]>
This commit is contained in:
David Howells 2017-11-24 10:18:42 +00:00
commit 415f44e432
4 changed files with 40 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

1
net/rxrpc/ar-internal.h
View file

@ -519,6 +519,7 @@ struct rxrpc_call {
unsigned long ack_lost_at; /* When ACK is figured as lost */
unsigned long resend_at; /* When next resend needs to happen */
unsigned long ping_at; /* When next to send a ping */
unsigned long keepalive_at; /* When next to send a keepalive ping */
unsigned long expect_rx_by; /* When we expect to get a packet by */
unsigned long expect_req_by; /* When we expect to get a request DATA packet by */
unsigned long expect_term_by; /* When we expect call termination by */

10
net/rxrpc/call_event.c
View file

@ -366,6 +366,15 @@ recheck_state:
set_bit(RXRPC_CALL_EV_ACK_LOST, &call->events);
}
t = READ_ONCE(call->keepalive_at);
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_keepalive, now);
cmpxchg(&call->keepalive_at, t, now + MAX_JIFFY_OFFSET);
rxrpc_propose_ACK(call, RXRPC_ACK_PING, 0, 0, true, true,
rxrpc_propose_ack_ping_for_keepalive);
set_bit(RXRPC_CALL_EV_PING, &call->events);
}
t = READ_ONCE(call->ping_at);
if (time_after_eq(now, t)) {
trace_rxrpc_timer(call, rxrpc_timer_exp_ping, now);
@ -423,6 +432,7 @@ recheck_state:
set(call->ack_at);
set(call->ack_lost_at);
set(call->resend_at);
set(call->keepalive_at);
set(call->ping_at);
now = jiffies;

23
net/rxrpc/output.c
View file

@ -32,6 +32,24 @@ struct rxrpc_abort_buffer {
__be32 abort_code;
};
/*
* Arrange for a keepalive ping a certain time after we last transmitted. This
* lets the far side know we're still interested in this call and helps keep
* the route through any intervening firewall open.
*
* Receiving a response to the ping will prevent the ->expect_rx_by timer from
* expiring.
*/
static void rxrpc_set_keepalive(struct rxrpc_call *call)
{
unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6;
keepalive_at += now;
WRITE_ONCE(call->keepalive_at, keepalive_at);
rxrpc_reduce_call_timer(call, keepalive_at, now,
rxrpc_timer_set_for_keepalive);
}
/*
* Fill out an ACK packet.
*/
@ -205,6 +223,8 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping,
call->ackr_seen = top;
spin_unlock_bh(&call->lock);
}
rxrpc_set_keepalive(call);
}
out:
@ -388,6 +408,9 @@ done:
}
}
}
rxrpc_set_keepalive(call);
_leave(" = %d [%u]", ret, call->peer->maxdata);
return ret;