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use super::request_admission::{Class, Rejection};
use super::*;
impl<T: TransportPort + 'static> BACnetServer<T> {
/// Admit an answer to a confirmed request this server sent. With
/// `local_network`, this network's number, known, an answer relayed with
/// it as SNET answers a request sent to its SADR (#1465), and teaches no
/// next hop: sends to this network go out locally.
async fn admit_notification_terminal(
learned_routers: &Arc<Mutex<LearnedRouterCache>>,
notification_transactions: &Arc<NotificationTransactions>,
source_mac: &[u8],
source_network: Option<&NpduAddress>,
local_network: Option<u16>,
apdu: &Apdu,
) -> bool {
if !notification_transactions.admit_terminal(
source_mac,
source_network,
local_network,
apdu,
) {
return false;
}
if let Some(source) = source_network.filter(|source| {
!source.mac_address.is_empty() && Some(source.network) != local_network
}) {
learned_routers
.lock()
.await
.learn_router(source.network, &MacAddr::from_slice(source_mac));
}
true
}
async fn route_segmented_send_event(
seg_ack_senders: &Arc<segmented_send::SegmentedSendRegistry>,
key: SegKey,
event: SegmentedSendEvent,
) -> bool {
let handle = {
let senders = seg_ack_senders.lock();
senders.get(&key).cloned()
};
let Some(handle) = handle else {
return false;
};
match event {
SegmentedSendEvent::Abort(abort) => {
handle.send_control(SegmentedSendControlEvent::Abort(abort));
true
}
SegmentedSendEvent::SegmentAck(ack) => {
let invoke_id = ack.invoke_id;
let seq = ack.sequence_number;
if !handle.accepts_segment_ack(&ack) {
debug!(
invoke_id,
seq,
negative = ack.negative_ack,
"Ignoring SegmentAck outside current segmented-send window"
);
return true;
}
match handle.segment_ack_tx.try_send(ack) {
Ok(()) => true,
Err(mpsc::error::TrySendError::Full(_)) => {
warn_throttled!(
seg_ack_senders.warning,
invoke_id,
seq,
"Dropping SegmentAck because segmented-send queue is full"
);
true
}
Err(mpsc::error::TrySendError::Closed(_)) => false,
}
}
}
}
/// Answer a confirmed request refused for capacity with a server Abort,
/// on one of the abort workers. The Abort's addressing is rebuilt from
/// `received` here rather than copied ahead of admission, so an admitted
/// request never pays for it (#1713).
fn spawn_overload_abort(
ctx: &DispatchContext<T>,
source_mac: &[u8],
received: &bacnet_network::layer::ReceivedApdu,
invoke_id: u8,
reply_tx: Option<oneshot::Sender<Bytes>>,
) {
let network = Arc::clone(&ctx.services.network);
let mac = MacAddr::from_slice(source_mac);
let source = received.source_network.clone();
let route = received.response_route();
let peer = super::request_peer::canonical_requester(&mac, source.as_ref());
let _ = ctx
.request_tasks
.try_spawn(Class::Abort, peer, || async move {
requests::confirmed_response::send_overload_response(
&network,
&Apdu::Abort(AbortPdu {
sent_by_server: true,
invoke_id,
abort_reason: AbortReason::OUT_OF_RESOURCES,
}),
&mac,
source.as_ref(),
&route,
reply_tx,
)
.await;
});
}
/// Dispatch a received APDU.
///
/// ConfirmedRequest and UnconfirmedRequest handlers are spawned as
/// independent tasks so the dispatch loop can immediately process the
/// next incoming APDU. This allows the server to handle multiple
/// client requests concurrently (e.g. concurrent ReadProperty via
/// the RwLock on ObjectDatabase).
///
/// Fast-path APDU types (SimpleAck, Error, Reject, Abort, SegmentAck)
/// remain inline since they are sub-microsecond TSM lookups.
pub(super) async fn dispatch(
ctx: &DispatchContext<T>,
source_mac: &[u8],
apdu: Apdu,
mut received: bacnet_network::layer::ReceivedApdu,
) {
let DispatchContext {
services,
confirmed_request_tracker,
clock: _,
discovery_limiter,
time_sync_limiter: _,
request_tasks,
} = ctx;
let RequestServices {
network,
seg_ack_senders,
learned_routers,
notification_transactions,
..
} = &**services;
if notification_transactions
.application_sealed
.load(Ordering::Acquire)
&& matches!(
apdu,
Apdu::ConfirmedRequest(_) | Apdu::UnconfirmedRequest(_)
)
{
return;
}
// Ingress provenance travels with `received` into request diagnostics
// and authorization. NotificationTransactions owns outgoing terminal
// admission; learned_routers stores only next hops from admitted replies.
let route = received.response_route();
match apdu {
Apdu::ConfirmedRequest(req) => {
// LSO-only replay path (server level, separate budget).
// Retransmitted already-executed confirmed LSO within the
// window resends byte-identical bytes with a single execution.
// Pending in-flight duplicates preserve DISCARD. This is a
// local service-specific extension, not a Standard mandate.
if req.service_choice == ConfirmedServiceChoice::LIFE_SAFETY_OPERATION {
let lso_pending = match confirmed_request_tracker.lso.begin(
source_mac,
received.source_network.as_ref(),
received.provenance.clone(),
req.clone(),
) {
LsoAdmission::Replay(bytes) => {
let reply_tx = received.reply_tx.take();
let replay_mac = MacAddr::from_slice(source_mac);
let replay_network = received.source_network.clone();
requests::confirmed_response::send_replay_bytes(
network,
&bytes,
&replay_mac,
replay_network.as_ref(),
&route,
reply_tx,
)
.await;
return;
}
LsoAdmission::DuplicatePending => return,
LsoAdmission::New(pending) => pending,
};
let invoke_id = req.invoke_id;
let mut reply_tx = received.reply_tx.take();
let services = services.clone();
let requester_mac = MacAddr::from_slice(source_mac);
let source_network = received.source_network.clone();
let descendants = request_tasks.spawner();
let peer = super::request_peer::canonical_requester(
&requester_mac,
source_network.as_ref(),
);
let class = super::request_admission::confirmed_class(
req.service_choice,
&req.service_request,
);
let result = request_tasks.try_spawn(class, peer, || {
let reply_tx = reply_tx.take();
async move {
Self::handle_admitted_confirmed_request(
&services,
&descendants,
RequestOrigin {
mac: &requester_mac,
network: source_network,
route,
},
req,
reply_tx,
Some(ConfirmedRequestOwnership::LifeSafety(lso_pending)),
)
.await;
}
});
if result == Err(Rejection::Overloaded) {
Self::spawn_overload_abort(ctx, source_mac, &received, invoke_id, reply_tx);
}
return;
}
let pending = match confirmed_request_tracker.begin(
source_mac,
received.source_network.as_ref(),
received.provenance.clone(),
req.clone(),
) {
ConfirmedRequestAdmission::Duplicate => return,
ConfirmedRequestAdmission::New(pending) => pending,
};
let invoke_id = req.invoke_id;
let mut reply_tx = received.reply_tx.take();
let services = services.clone();
let requester_mac = MacAddr::from_slice(source_mac);
let source_network = received.source_network.clone();
let descendants = request_tasks.spawner();
let peer = super::request_peer::canonical_requester(
&requester_mac,
source_network.as_ref(),
);
let class = super::request_admission::confirmed_class(
req.service_choice,
&req.service_request,
);
let result = request_tasks.try_spawn(class, peer, || {
Self::run_admitted_confirmed_request(requests::read_property::AdmittedRequest {
services,
request_tasks: descendants,
source_mac: requester_mac,
source_network,
route,
req,
reply_tx: reply_tx.take(),
ownership: Some(ConfirmedRequestOwnership::Generic(pending)),
})
});
if result == Err(Rejection::Overloaded) {
// ASHRAE 135-2020 §§5.4.5.3, 18.10: resource exhaustion
// before service execution is reported by a server Abort.
// Eight owned sends bound this response work. If all are
// busy, the counted silent drop is a known local limitation.
Self::spawn_overload_abort(ctx, source_mac, &received, invoke_id, reply_tx);
}
}
Apdu::UnconfirmedRequest(req) => {
let now = runtime_clock::now();
if req.service_choice == UnconfirmedServiceChoice::WHO_IS {
match discovery_limiter.pre_check_who_is(&req.service_request, &received, now) {
PreCheckDecision::Admit => {}
PreCheckDecision::OutOfRange => {
debug!("WhoIs instance range does not include local device; dropped");
return;
}
PreCheckDecision::Coalesced => {
debug!("WhoIs duplicate coalesced within window");
return;
}
PreCheckDecision::ThrottledSource => {
debug!("WhoIs throttled: source rate/byte limit exceeded");
return;
}
PreCheckDecision::ThrottledGlobal => {
debug!("WhoIs throttled: global rate/byte limit exceeded");
return;
}
// Nothing can answer it: drop it here, before a
// task is spawned and it is decoded again.
PreCheckDecision::DecodeError => {
debug!("Malformed WhoIs dropped");
return;
}
}
} else if req.service_choice == UnconfirmedServiceChoice::WHO_HAS {
match discovery_limiter.pre_check_who_has(&req.service_request, &received, now)
{
PreCheckDecision::Admit => {}
PreCheckDecision::OutOfRange => {
debug!("WhoHas instance range does not include local device; dropped");
return;
}
PreCheckDecision::Coalesced => {
debug!("WhoHas duplicate/negative coalesced within window");
return;
}
PreCheckDecision::ThrottledSource => {
debug!("WhoHas throttled: source rate/byte limit exceeded");
return;
}
PreCheckDecision::ThrottledGlobal => {
debug!("WhoHas throttled: global rate/byte limit exceeded");
return;
}
PreCheckDecision::DecodeError => {
debug!("Malformed WhoHas dropped");
return;
}
}
}
let services = ctx.unconfirmed_services();
let peer = super::request_peer::canonical_requester(
source_mac,
received.source_network.as_ref(),
);
let _ = request_tasks.try_spawn(Class::Unconfirmed, peer, || async move {
Self::handle_unconfirmed_request(&services, req, &received).await;
});
}
// Fast paths — remain inline (bounded synchronous admission)
Apdu::SimpleAck(sa) => {
let invoke_id = sa.invoke_id;
let admitted = Self::admit_notification_terminal(
learned_routers,
notification_transactions,
source_mac,
received.source_network.as_ref(),
network.local_network_number().get(),
&Apdu::SimpleAck(sa),
)
.await;
debug!(
invoke_id,
admitted, "SimpleAck received for outgoing confirmed notification"
);
}
Apdu::Error(err) => {
let invoke_id = err.invoke_id;
let error_class = err.error_class.to_raw();
let error_code = err.error_code.to_raw();
let admitted = Self::admit_notification_terminal(
learned_routers,
notification_transactions,
source_mac,
received.source_network.as_ref(),
network.local_network_number().get(),
&Apdu::Error(err),
)
.await;
debug!(
invoke_id,
error_class,
error_code,
admitted,
"Error received for outgoing confirmed notification"
);
}
Apdu::Reject(rej) => {
let invoke_id = rej.invoke_id;
let admitted = Self::admit_notification_terminal(
learned_routers,
notification_transactions,
source_mac,
received.source_network.as_ref(),
network.local_network_number().get(),
&Apdu::Reject(rej),
)
.await;
debug!(
invoke_id,
admitted, "Reject received for outgoing confirmed notification"
);
}
Apdu::Abort(abort) => {
let invoke_id = abort.invoke_id;
let routed_segmented = if abort.sent_by_server {
false
} else {
let key = segmented_transaction_key(
source_mac,
received.source_network.as_ref(),
invoke_id,
route.provenance(),
);
Self::route_segmented_send_event(
seg_ack_senders,
key,
SegmentedSendEvent::Abort(abort.clone()),
)
.await
};
let admitted = Self::admit_notification_terminal(
learned_routers,
notification_transactions,
source_mac,
received.source_network.as_ref(),
network.local_network_number().get(),
&Apdu::Abort(abort),
)
.await;
debug!(
invoke_id,
routed_segmented,
admitted,
"Abort received for outgoing confirmed notification or segmented response"
);
}
Apdu::SegmentAck(sa) => {
let invoke_id = sa.invoke_id;
if sa.sent_by_server {
debug!(
invoke_id,
seq = sa.sequence_number,
"Server ignoring SegmentAck with server bit set"
);
return;
}
let key = segmented_transaction_key(
source_mac,
received.source_network.as_ref(),
invoke_id,
route.provenance(),
);
if !Self::route_segmented_send_event(
seg_ack_senders,
key,
SegmentedSendEvent::SegmentAck(sa),
)
.await
{
debug!(
invoke_id,
"Server ignoring SegmentAck for unknown transaction"
);
}
}
Apdu::ComplexAck(ack) => {
let invoke_id = ack.invoke_id;
let admitted = Self::admit_notification_terminal(
learned_routers,
notification_transactions,
source_mac,
received.source_network.as_ref(),
network.local_network_number().get(),
&Apdu::ComplexAck(ack),
)
.await;
if admitted {
debug!(invoke_id, "ComplexAck answered a read this server sent");
} else {
debug!(invoke_id, "Server ignoring ComplexAck it has no read for");
}
}
}
}
}