Function libp2p_core::address_translation

pub fn address_translation(
    original: &Multiaddr,
    observed: &Multiaddr
) -> Option<Multiaddr>

Perform IP address translation.

Given an original Multiaddr and some observed Multiaddr, replace the first protocol of the original with the first protocol of the observed Multiaddr and return this translated Multiaddr.

This function can for example be useful when handling tcp connections. Tcp does not listen and dial on the same port by default. Thus when receiving an observed address on a connection that we initiated, it will contain our dialing port, not our listening port. We need to take the ip address or dns address from the observed address and the port from the original address.

This is a mixed-mode translation, i.e. an IPv4 / DNS4 address may be replaced by an IPv6 / DNS6 address and vice versa.

If the first Protocols are not IP addresses, None is returned instead.