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Don't ack if we aren't being used in a route

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This commit is contained in:
Jeremy Lakeman 2013-05-16 14:06:08 +09:30
parent 5b4e4919cf
commit a213872f09
2 changed files with 41 additions and 21 deletions
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44
route_link.c
View File

@ -83,6 +83,9 @@ struct neighbour{
// when do we assume the link is dead because they stopped hearing us or vice versa?
time_ms_t neighbour_link_timeout;
// if a neighbour is telling the world that they are using us as a next hop, we need to send acks & nacks with high priority
// otherwise we don't care too much about packet loss.
time_ms_t using_us_timeout;
// next link update
time_ms_t next_neighbour_update;
@ -570,7 +573,9 @@ static int neighbour_find_best_link(struct neighbour *n)
static int neighbour_link_sent(struct overlay_frame *frame, int sequence, void *context)
{
struct subscriber *subscriber = context;
struct neighbour *neighbour = get_neighbour(subscriber, 1);
struct neighbour *neighbour = get_neighbour(subscriber, 0);
if (!neighbour)
return 0;
neighbour->last_update_seq = sequence;
if (config.debug.linkstate && config.debug.verbose)
DEBUGF("LINK STATE; ack sent to neighbour %s in seq %d", alloca_tohex_sid(subscriber->sid), sequence);
@ -734,9 +739,12 @@ int link_state_interface_has_neighbour(struct overlay_interface *interface)
// when we receive a packet from a neighbour with ourselves as the next hop, make sure we send an ack soon(ish)
int link_state_ack_soon(struct subscriber *subscriber){
IN();
struct neighbour *neighbour = get_neighbour(subscriber, 1);
struct neighbour *neighbour = get_neighbour(subscriber, 0);
if (!neighbour)
RETURN(0);
time_ms_t now = gettime_ms();
if (neighbour->next_neighbour_update > now + 80){
if (neighbour->using_us_timeout > now && neighbour->next_neighbour_update > now + 80){
neighbour->next_neighbour_update = now + 80;
}
update_alarm(neighbour->next_neighbour_update);
@ -751,7 +759,10 @@ int link_received_duplicate(struct subscriber *subscriber, struct overlay_interf
if (unicast)
return 0;
struct neighbour *neighbour = get_neighbour(subscriber, 1);
struct neighbour *neighbour = get_neighbour(subscriber, 0);
if (!neighbour)
return 0;
struct neighbour_link *link=get_neighbour_link(neighbour, interface, sender_interface, unicast);
int offset = (link->ack_sequence - 1 - previous_seq)&0xFF;
@ -794,13 +805,18 @@ int link_received_packet(struct subscriber *subscriber, struct overlay_interface
link->ack_sequence, alloca_tohex_sid(subscriber->sid), interface->name);
link->ack_mask = link->ack_mask << 1;
neighbour->ack_counter --;
// if we need to nack promptly
if (neighbour->using_us_timeout > now){
neighbour->next_neighbour_update = now + 10;
if (neighbour->ack_counter <=0){
neighbour_find_best_link(neighbour);
send_neighbour_link(neighbour);
}
}
}
}
}else
link->ack_sequence = sender_seq;
}
@ -812,8 +828,8 @@ int link_received_packet(struct subscriber *subscriber, struct overlay_interface
}
link->link_timeout = now + (interface->tick_ms *5);
// force an update soon when we need to ack packets
if (neighbour->ack_counter <=0){
// force an update soon when we need to promptly ack packets
if (neighbour->using_us_timeout > now && neighbour->ack_counter <=0){
neighbour_find_best_link(neighbour);
send_neighbour_link(neighbour);
}
@ -877,8 +893,9 @@ int link_receive(overlay_mdp_frame *mdp)
ack_mask = ob_get_ui32(payload);
drop_rate = 15 - NumberOfSetBits((ack_mask & 0x7FFF));
// we can deal with low packet loss, it's not interesting if it changes, ignore it.
if (drop_rate <=2)
// we can deal with low packet loss, and with fast packet transmission rates we're going to see lots of broadcast collisions.
// we only want to force a link update when packet loss due to interference is high. Otherwise ignore it.
if (drop_rate <=3)
drop_rate = 0;
}
@ -903,9 +920,16 @@ int link_receive(overlay_mdp_frame *mdp)
ack_mask,
drop_rate);
// ignore any links that our neighbour is using to route through us.
if (receiver == my_subscriber)
if (receiver == my_subscriber){
// track if our neighbour is using our network link, if they are we need to ack / nack promptly
if (transmitter == sender)
neighbour->using_us_timeout = now + 500;
else
neighbour->using_us_timeout = 0;
// for routing, we can completely ignore any links that our neighbour is using to route through us.
continue;
}
// ignore other incoming links to our neighbour
// TODO build a map of everyone in our 2 hop neighbourhood to control broadcast flooding?

10
tests/routing
View File

@ -381,11 +381,11 @@ test_ping_unreliable() {
wait_until path_exists +A +B
wait_until path_exists +B +A
set_instance +A
executeOk_servald mdp ping --interval=0.020 --timeout=1 $SIDB 500
executeOk_servald mdp ping --interval=0.020 --timeout=2 $SIDB 500
tfw_cat --stdout --stderr
}
doc_unreliable_links="Choose a longer, better path over an unreliable link"
doc_unreliable_links="Prefer a longer, better path vs an unreliable link"
setup_unreliable_links() {
setup_servald
assert_no_servald_processes
@ -411,7 +411,7 @@ test_unreliable_links() {
wait_until path_exists +A +B +C
wait_until path_exists +C +B +A
set_instance +A
executeOk_servald mdp ping --timeout=3 $SIDC 5
executeOk_servald mdp ping --interval=0.100 --timeout=3 $SIDC 30
tfw_cat --stdout --stderr
executeOk_servald route print
assertStdoutGrep --matches=1 "^$SIDC:INDIRECT :"
@ -490,10 +490,6 @@ test_circle() {
stop_servald_server +B
foreach_instance +A +C \
wait_until --timeout=10 instance_offline +B
set_instance +A
wait_until --timeout=10 instance_offline +C
set_instance +C
wait_until --timeout=10 instance_offline +A
wait_until path_exists +A +H +G +F +E +D +C
wait_until path_exists +C +D +E +F +G +H +A
set_instance +A