Reset expiry of entries in the neighbor cache on packet reception

Author: korken89

src/iface/interface/ethernet.rs

@@ -25,13 +25,13 @@ impl InterfaceInner {
             EthernetProtocol::Ipv4 => {
                 let ipv4_packet = check!(Ipv4Packet::new_checked(eth_frame.payload()));
 
-                self.process_ipv4(sockets, meta, &ipv4_packet, fragments)
+                self.process_ipv4(sockets, self.now, meta, &ipv4_packet, fragments)
                     .map(EthernetPacket::Ip)
             }
             #[cfg(feature = "proto-ipv6")]
             EthernetProtocol::Ipv6 => {
                 let ipv6_packet = check!(Ipv6Packet::new_checked(eth_frame.payload()));
-                self.process_ipv6(sockets, meta, &ipv6_packet)
+                self.process_ipv6(sockets, self.now, meta, &ipv6_packet)
                     .map(EthernetPacket::Ip)
             }
             // Drop all other traffic.

src/iface/interface/ipv4.rs

@@ -90,6 +90,7 @@ impl InterfaceInner {
     pub(super) fn process_ipv4<'a>(
         &mut self,
         sockets: &mut SocketSet,
+        timestamp: Instant,
         meta: PacketMeta,
         ipv4_packet: &Ipv4Packet<&'a [u8]>,
         frag: &'a mut FragmentsBuffer,
@@ -196,6 +197,9 @@ impl InterfaceInner {
             }
         }
 
+        self.neighbor_cache
+            .reset_expiry_if_existing(IpAddress::Ipv4(ipv4_repr.src_addr), timestamp);
+
         match ipv4_repr.next_header {
             IpProtocol::Icmp => self.process_icmpv4(sockets, ipv4_repr, ip_payload),
 

src/iface/interface/ipv6.rs

@@ -186,6 +186,7 @@ impl InterfaceInner {
     pub(super) fn process_ipv6<'frame>(
         &mut self,
         sockets: &mut SocketSet,
+        timestamp: Instant,
         meta: PacketMeta,
         ipv6_packet: &Ipv6Packet<&'frame [u8]>,
     ) -> Option<Packet<'frame>> {
@@ -228,6 +229,9 @@ impl InterfaceInner {
         #[cfg(not(feature = "socket-raw"))]
         let handled_by_raw_socket = false;
 
+        self.neighbor_cache
+            .reset_expiry_if_existing(IpAddress::Ipv6(ipv6_repr.src_addr), timestamp);
+
         self.process_nxt_hdr(
             sockets,
             meta,

src/iface/neighbor.rs

@@ -63,6 +63,17 @@ impl Cache {
         }
     }
 
+    pub fn reset_expiry_if_existing(&mut self, protocol_addr: IpAddress, timestamp: Instant) {
+        if let Some(Neighbor {
+            expires_at,
+            hardware_addr: _,
+        }) = self.storage.get_mut(&protocol_addr)
+        {
+            net_trace!("reseting expiry for {}", protocol_addr);
+            *expires_at = timestamp + Self::ENTRY_LIFETIME;
+        }
+    }
+
     pub fn fill(
         &mut self,
         protocol_addr: IpAddress,