Crash due to assertion failure

[black-binary]

My code crashed after inputting some packets.

Here is a part of the stack backtrace:

Abort message: 'assertion failed: addr.is_unicast()'

(...)
core::panicking::panic::h945a80aaa5884f5b+48
smoltcp::iface::route::Routes::lookup::hc3ac269274d45dbb+1240
smoltcp::iface::interface::InterfaceInner::process_ip::hc48da65fc6377e67+1844
(my rx token consume function)
(interface::poll function)
(...)

lookup was called from here.

smoltcp/src/iface/interface.rs

Lines 1235 to 1249 in dedfbe1

	if !self.has_ip_addr(ipv4_repr.dst_addr)
	&& !self.has_multicast_group(ipv4_repr.dst_addr)
	&& !self.is_broadcast_v4(ipv4_repr.dst_addr)
	{
	// Ignore IP packets not directed at us, or broadcast, or any of the multicast groups.
	// If AnyIP is enabled, also check if the packet is routed locally.
	if !self.any_ip
	|| self
	.routes
	.lookup(&IpAddress::Ipv4(ipv4_repr.dst_addr), cx.now)
	.map_or(true, |router_addr| !self.has_ip_addr(router_addr))
	{
	return Ok(None);
	}
	}

The assertion failed at the beginning of the lookup function and caused panic.

smoltcp/src/iface/route.rs

Lines 129 to 133 in dedfbe1

	pub(crate) fn lookup(&self, addr: &IpAddress, timestamp: Instant) -> Option<IpAddress> {
	assert!(addr.is_unicast());
	let cidr = match addr {
	#[cfg(feature = "proto-ipv4")]

[black-binary]

Maybe we should fix this by adding more conditions.

smoltcp/src/iface/interface.rs

Lines 1235 to 1237 in dedfbe1

	if !self.has_ip_addr(ipv4_repr.dst_addr)
	&& !self.has_multicast_group(ipv4_repr.dst_addr)
	&& !self.is_broadcast_v4(ipv4_repr.dst_addr)

->

 if !self.has_ip_addr(ipv4_repr.dst_addr) 
     && !self.has_multicast_group(ipv4_repr.dst_addr) 
     && !self.is_broadcast_v4(ipv4_repr.dst_addr) 
     && ipv4_repr.dst_addr.is_unicast()

[Dirbaio]

Nice catch! The fix is adding the condition in the inner if, since we do want to ignore these packets (multicast dst_addr that we're not subscribed to). Fix in #534