Struct NatEngine 

pub struct NatEngine {
    pub port_pool: PortPool,
    pub mappings: BTreeMap<ConntrackKey, NatMapping>,
    pub masquerade_addr: Ipv4Address,
    pub total_translations: u64,
}

The NAT engine managing translations and port allocation

Fields

port_pool: PortPool

Ephemeral port pool

mappings: BTreeMap<ConntrackKey, NatMapping>

Active NAT mappings indexed by original connection key

masquerade_addr: Ipv4Address

Masquerade address (outgoing interface IP)

total_translations: u64

Total translations performed

Implementations

impl NatEngine

pub fn new() -> Self

Create a new NAT engine

pub fn set_masquerade_addr(&mut self, addr: Ipv4Address)

Set the masquerade (outgoing interface) address

pub fn translate_outbound_snat( &mut self, key: &ConntrackKey, new_src_ip: Ipv4Address, ) -> Option<NatMapping>

Translate an outbound packet with SNAT

Rewrites the source address and allocates a new source port. Returns the NAT mapping on success.

pub fn translate_outbound_masquerade( &mut self, key: &ConntrackKey, ) -> Option<NatMapping>

Translate an outbound packet with masquerading

Uses the configured masquerade address as the source.

pub fn translate_inbound_dnat( &mut self, key: &ConntrackKey, new_dst_ip: Ipv4Address, new_dst_port: Port, ) -> Option<NatMapping>

Translate an inbound packet with DNAT

Rewrites the destination address and port.

pub fn lookup_reverse(&self, reply_key: &ConntrackKey) -> Option<&NatMapping>

Look up a reverse NAT mapping for inbound reply traffic

Given a reply packet’s key, find the corresponding SNAT/masquerade mapping to reverse the translation.

pub fn remove_mapping(&mut self, key: &ConntrackKey) -> Option<NatMapping>

Remove a NAT mapping and release its allocated port

pub fn mapping_count(&self) -> usize

Number of active mappings

Trait Implementations

impl Default for NatEngine

fn default() -> Self

Returns the “default value” for a type.