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Simplify ARP handling code in EthernetInterface.

This commit is contained in:
whitequark 2017-08-21 07:08:06 +00:00
parent 15085bd8ba
commit 925e13b61a
1 changed files with 11 additions and 18 deletions
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29
src/iface/ethernet.rs
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@ -145,19 +145,23 @@ impl<'a, 'b, 'c, DeviceT: Device + 'a> Interface<'a, 'b, 'c, DeviceT> {
let arp_repr = ArpRepr::parse(&arp_packet)?;
match arp_repr {
// Respond to ARP requests aimed at us, and fill the ARP cache
// from all ARP requests, including gratuitous.
// Respond to ARP requests aimed at us, and fill the ARP cache from all ARP
// requests and replies, to minimize the chance that we have to perform
// an explicit ARP request.
ArpRepr::EthernetIpv4 {
operation: ArpOperation::Request,
source_hardware_addr, source_protocol_addr,
target_protocol_addr, ..
operation, source_hardware_addr, source_protocol_addr, target_protocol_addr, ..
} => {
if source_protocol_addr.is_unicast() && source_hardware_addr.is_unicast() {
self.arp_cache.fill(&source_protocol_addr.into(),
&source_hardware_addr);
} else {
// Discard packets with non-unicast source addresses.
net_debug!("non-unicast source in {}", arp_repr);
return Err(Error::Malformed)
}
if self.has_protocol_addr(target_protocol_addr) {
if operation == ArpOperation::Reply &&
self.has_protocol_addr(target_protocol_addr) {
Ok(Response::Arp(ArpRepr::EthernetIpv4 {
operation: ArpOperation::Reply,
source_hardware_addr: self.hardware_addr,
@ -170,18 +174,6 @@ impl<'a, 'b, 'c, DeviceT: Device + 'a> Interface<'a, 'b, 'c, DeviceT> {
}
}
// Fill the ARP cache from gratuitous ARP replies.
ArpRepr::EthernetIpv4 {
operation: ArpOperation::Reply,
source_hardware_addr, source_protocol_addr, ..
} => {
if source_protocol_addr.is_unicast() && source_hardware_addr.is_unicast() {
self.arp_cache.fill(&source_protocol_addr.into(),
&source_hardware_addr);
}
Ok(Response::Nop)
}
_ => Err(Error::Unrecognized)
}
}
@ -195,6 +187,7 @@ impl<'a, 'b, 'c, DeviceT: Device + 'a> Interface<'a, 'b, 'c, DeviceT> {
if !ipv4_repr.src_addr.is_unicast() {
// Discard packets with non-unicast source addresses.
net_debug!("non-unicast source in {}", ipv4_repr);
return Err(Error::Malformed)
}