Struct ArpLayer 

pub struct ArpLayer {
    cache: RwLock<BTreeMap<(String, u32), ArpCacheEntry>>,
    pending: RwLock<BTreeMap<(String, u32), ArpPendingEntry>>,
    timeout_ticks: u64,
    cache_timeout: u64,
    stats: RwLock<NetworkLayerStats>,
    packet_counter: AtomicU32,
}

ARP layer

Manages ARP cache and handles ARP requests/replies. Implements NetworkLayer trait for integration with protocol stack.

Design

The ARP layer is fully interface-aware:

• Cache is per-interface: (interface, IP) -> MAC
• Each interface has its own ARP table
• MAC/IP addresses are obtained from EthernetLayer/Ipv4Layer

Fields

cache: RwLock<BTreeMap<(String, u32), ArpCacheEntry>>

ARP cache: (interface_name, IP) -> entry

pending: RwLock<BTreeMap<(String, u32), ArpPendingEntry>>

Pending ARP resolutions: (interface_name, IP) -> pending entry

timeout_ticks: u64

Packet timeout (in ticks)

cache_timeout: u64

Cache timeout (in ticks)

stats: RwLock<NetworkLayerStats>

Statistics

packet_counter: AtomicU32

Counter for packet queueing

Implementations

impl ArpLayer

pub fn new() -> Arc<Self>

Create a new ARP layer

pub fn init(network_manager: &NetworkManager)

Initialize and register the ARP layer with NetworkManager

Registers with NetworkManager and registers itself with EthernetLayer for EtherType 0x0806 (ARP).

Panics

Panics if EthernetLayer is not registered (must be initialized first).

fn get_local_mac_for_interface(&self, interface: &str) -> Option<[u8; 6]>

Get local MAC address for an interface from EthernetLayer

fn get_local_ip_for_interface(&self, interface: &str) -> Option<Ipv4Address>

Get local IP address for an interface from Ipv4Layer

fn get_default_interface(&self) -> Option<String>

Get default interface name from EthernetLayer

pub fn lookup_on_interface( &self, interface: &str, ip_address: Ipv4Address, ) -> Option<[u8; 6]>

Look up MAC address for an IP on a specific interface

pub fn lookup(&self, ip_address: Ipv4Address) -> Option<[u8; 6]>

Look up MAC address for an IP (uses default interface)

pub fn add_entry_on_interface( &self, interface: &str, ip_address: Ipv4Address, mac_address: [u8; 6], )

Add entry to ARP cache for a specific interface

pub fn add_entry(&self, ip_address: Ipv4Address, mac_address: [u8; 6])

Add entry to ARP cache (uses default interface)

pub fn remove_entry_on_interface( &self, interface: &str, ip_address: Ipv4Address, )

Remove entry from ARP cache for a specific interface

pub fn remove_entry(&self, ip_address: Ipv4Address)

Remove entry from ARP cache (uses default interface)

pub fn send_request( &self, target_ip: Ipv4Address, context: &LayerContext, next_layers: &[Arc<dyn NetworkLayer>], ) -> Result<(), SocketError>

Send ARP request

Arguments

• target_ip - IP address to resolve
• context - Layer context (may contain “interface” key)
• next_layers - Layers to pass through (typically Ethernet)

pub fn receive_packet_on_interface( &self, arp_bytes: &[u8], interface: Option<&str>, ) -> Result<(), SocketError>

Process received ARP packet

Arguments

• arp_bytes - Raw ARP packet bytes
• interface - Interface the packet was received on (optional)

pub fn receive_packet(&self, arp_bytes: &[u8]) -> Result<(), SocketError>

Process received ARP packet (legacy interface)

pub fn queue_packet_on_interface( &self, interface: &str, ip_address: Ipv4Address, packet: Vec<u8>, )

Queue a packet waiting for ARP resolution on a specific interface

pub fn queue_packet(&self, ip_address: Ipv4Address, packet: Vec<u8>)

Queue a packet waiting for ARP resolution (uses default interface)

fn get_timestamp(&self) -> u64

Get current timestamp (placeholder - should use actual system time)

pub fn is_resolved(&self, ip_address: Ipv4Address) -> bool

Check if IP address is resolved on default interface

pub fn is_resolved_on_interface( &self, interface: &str, ip_address: Ipv4Address, ) -> bool

Check if IP address is resolved on a specific interface

Trait Implementations

impl NetworkLayer for ArpLayer

fn register_protocol(&self, _proto_num: u16, _handler: Arc<dyn NetworkLayer>)

Register a protocol handler for this layer

fn send( &self, _packet: &[u8], _context: &LayerContext, _next_layers: &[Arc<dyn NetworkLayer>], ) -> Result<(), SocketError>

Send a packet through this layer

fn receive( &self, packet: &[u8], _context: Option<&LayerContext>, ) -> Result<(), SocketError>

Receive and process a packet at this layer

fn name(&self) -> &'static str

Get layer name for debugging

fn stats(&self) -> NetworkLayerStats

Get layer statistics

fn as_any(&self) -> &dyn Any

Cast to Any for safe downcasting

fn configure( &self, config: &SocketConfig, next_layers: &[Arc<dyn NetworkLayer>], ) -> Result<(), SocketError>

Configure this layer with socket-specific parameters