pcap_int

An implementation of freertr's pcapInt in Rust using the
libc and pcap crates.

Improvements to the original:

clearer CLI arguments
full IPv6 support
clearer error messages
support for daemonizing
support for resolving hostnames
optional support for encryption (using the XChaCha20Poly1305 algorithm) using the orion crate.


Options:
 --list_interfaces
 --version

Usage:
 --iface_name <str>      Name of the interface to capture on
 --laddr <socket addr>   Listen address
 --raddr <socket addr>   Remote address
 --daemonize             Run as a daemon
 ```

### Features
- `crypto`: encryption using XChaCha20Poly1305. The key must be 32 bits long, and should be the same on both sides of the tunnel.