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RunState: Implement forward_network_time_if_applicable()

Browse source 
Add a central place where the decision when it's okay to update network time
to the current time (wallclock) is. It checks for pseudo_realtime and packet
source existence as well as packet source idleness.

A new const &redef allows to completely disable forwarding of network time.
This commit is contained in:
Arne Welzel 2023-03-15 15:03:17 +01:00
parent eefa0150b9
commit d4e31e7d2b
4 changed files with 80 additions and 13 deletions
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62
src/RunState.cc
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@ -137,6 +137,44 @@ void update_network_time(double new_network_time)
PLUGIN_HOOK_VOID(HOOK_UPDATE_NETWORK_TIME, HookUpdateNetworkTime(new_network_time));
}
// Logic to decide when updating network_time is acceptable:
static bool should_forward_network_time()
{
// In pseudo_realtime mode, always update time once
// we've dispatched and processed the first packet.
// run_state::detail::first_timestamp is currently set
// in PktSrc::ExtractNextPacketInternal()
if ( pseudo_realtime != 0.0 && run_state::detail::first_timestamp != 0.0 )
return true;
if ( iosource::PktSrc* ps = iosource_mgr->GetPktSrc() )
{
// Offline packet sources always control network time
// unless we're running pseudo_realtime, see above.
if ( ! ps->IsLive() )
return false;
if ( ! ps->HasBeenIdleFor(BifConst::packet_source_inactivity_timeout) )
return false;
}
// We determined that we don't have a packet source, or it is idle.
// Unless it has been disabled, network_time will now be moved forward.
return BifConst::allow_network_time_forward;
}
static void forward_network_time_if_applicable()
{
if ( ! should_forward_network_time() )
return;
double now = util::current_time(true);
if ( now > network_time )
update_network_time(now);
return;
}
void init_run(const std::optional<std::string>& interface,
const std::optional<std::string>& pcap_input_file,
const std::optional<std::string>& pcap_output_file, bool do_watchdog)
@ -319,21 +357,21 @@ void run_loop()
// date on timers and events. Because we only
// have timers as sources, going to sleep here
// doesn't risk blocking on other inputs.
update_network_time(util::current_time());
//
// TBD: Is this actually still relevant given that the TimerMgr
// is an IO source now? It'll be processed once its
// GetNextTimeout() yields 0 and before that there's nothing
// to expire anyway.
forward_network_time_if_applicable();
expire_timers();
// Prevent another forward_network_time_if_applicable() below
// even if time wasn't actually updated.
time_updated = true;
}
// Ensure that the time gets updated every pass if we're reading live.
// This is necessary for e.g. packet sources that don't have a selectable
// file descriptor. They'll always be ready on a very short timeout, but
// won't necessarily have a packet to process. In these case, sometimes
// the time won't get updated for a long time and timers don't function
// correctly.
if ( (! time_updated && reading_live) )
{
update_network_time(util::current_time());
expire_timers();
}
if ( ! time_updated )
forward_network_time_if_applicable();
event_mgr.Drain();