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Jul 23, 2024
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Limiting the number of poll loops to prevent DoS events #954

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3 changes: 2 additions & 1 deletion CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

## [Unreleased]

No unreleased changes yet.
### Changed
- iface: The `poll` function now only performs a single cycle of processing sockets ([#954](https://github.com/smoltcp-rs/smoltcp/pull/954))

## [0.11.0] - 2023-12-23

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130 changes: 62 additions & 68 deletions src/iface/interface/mod.rs
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Expand Up @@ -396,6 +396,13 @@ impl Interface {
/// This function returns a boolean value indicating whether any packets were
/// processed or emitted, and thus, whether the readiness of any socket might
/// have changed.
///
/// # Note
/// This function performs a bounded amount of work per call to avoid
/// starving other tasks of CPU time. If it returns true, there may still be
/// packets to be received or transmitted. Depending on system design,
/// calling this function in a loop may cause a denial of service if
/// packets cannot be processed faster than they arrive.
pub fn poll<D>(
&mut self,
timestamp: Instant,
Expand Down Expand Up @@ -429,23 +436,12 @@ impl Interface {
}
}

let mut readiness_may_have_changed = false;

loop {
let mut did_something = false;
did_something |= self.socket_ingress(device, sockets);
did_something |= self.socket_egress(device, sockets);

#[cfg(feature = "proto-igmp")]
{
did_something |= self.igmp_egress(device);
}
let mut readiness_may_have_changed = self.socket_ingress(device, sockets);
readiness_may_have_changed |= self.socket_egress(device, sockets);

if did_something {
readiness_may_have_changed = true;
} else {
break;
}
#[cfg(feature = "proto-igmp")]
{
readiness_may_have_changed |= self.igmp_egress(device);
}

readiness_may_have_changed
Expand Down Expand Up @@ -507,67 +503,65 @@ impl Interface {
{
let mut processed_any = false;

while let Some((rx_token, tx_token)) = device.receive(self.inner.now) {
let rx_meta = rx_token.meta();
rx_token.consume(|frame| {
if frame.is_empty() {
return;
}
let Some((rx_token, tx_token)) = device.receive(self.inner.now) else {
return processed_any;
};

match self.inner.caps.medium {
#[cfg(feature = "medium-ethernet")]
Medium::Ethernet => {
if let Some(packet) = self.inner.process_ethernet(
sockets,
rx_meta,
frame,
&mut self.fragments,
) {
if let Err(err) =
self.inner.dispatch(tx_token, packet, &mut self.fragmenter)
{
net_debug!("Failed to send response: {:?}", err);
}
let rx_meta = rx_token.meta();
rx_token.consume(|frame| {
if frame.is_empty() {
return;
}

match self.inner.caps.medium {
#[cfg(feature = "medium-ethernet")]
Medium::Ethernet => {
if let Some(packet) =
self.inner
.process_ethernet(sockets, rx_meta, frame, &mut self.fragments)
{
if let Err(err) =
self.inner.dispatch(tx_token, packet, &mut self.fragmenter)
{
net_debug!("Failed to send response: {:?}", err);
}
}
#[cfg(feature = "medium-ip")]
Medium::Ip => {
if let Some(packet) =
self.inner
.process_ip(sockets, rx_meta, frame, &mut self.fragments)
{
if let Err(err) = self.inner.dispatch_ip(
tx_token,
PacketMeta::default(),
packet,
&mut self.fragmenter,
) {
net_debug!("Failed to send response: {:?}", err);
}
}
#[cfg(feature = "medium-ip")]
Medium::Ip => {
if let Some(packet) =
self.inner
.process_ip(sockets, rx_meta, frame, &mut self.fragments)
{
if let Err(err) = self.inner.dispatch_ip(
tx_token,
PacketMeta::default(),
packet,
&mut self.fragmenter,
) {
net_debug!("Failed to send response: {:?}", err);
}
}
#[cfg(feature = "medium-ieee802154")]
Medium::Ieee802154 => {
if let Some(packet) = self.inner.process_ieee802154(
sockets,
rx_meta,
frame,
&mut self.fragments,
}
#[cfg(feature = "medium-ieee802154")]
Medium::Ieee802154 => {
if let Some(packet) =
self.inner
.process_ieee802154(sockets, rx_meta, frame, &mut self.fragments)
{
if let Err(err) = self.inner.dispatch_ip(
tx_token,
PacketMeta::default(),
packet,
&mut self.fragmenter,
) {
if let Err(err) = self.inner.dispatch_ip(
tx_token,
PacketMeta::default(),
packet,
&mut self.fragmenter,
) {
net_debug!("Failed to send response: {:?}", err);
}
net_debug!("Failed to send response: {:?}", err);
}
}
}
processed_any = true;
});
}
}
processed_any = true;
});

processed_any
}
Expand Down
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