netaddr

What

This is a package containing a new IP address type for Go.

See its docs: https://pkg.go.dev/inet.af/netaddr

Motivation

See https://tailscale.com/blog/netaddr-new-ip-type-for-go/ for a long blog post about why we made a new IP address package.

Other links:

• golang/go#18804 ("net: reconsider representation of IP")
• golang/go#18757 ("net: ParseIP should return an error, like other Parse functions")
• golang/go#37921 ("net: Unable to reliably distinguish IPv4-mapped-IPv6 addresses from regular IPv4 addresses")
• merges net.IPAddr and net.IP (which the Go net package is a little torn between for legacy reasons)
• ...
• TODO: finish this list

Maturity

This package is mature, optimized, and used heavily in production at Tailscale. However, API stability is not yet guaranteed.

Testing

In addition to regular Go tests, netaddr uses fuzzing. The corpus is stored separately, in a submodule, to minimize the impact on everyone else.

To use:

$ git submodule update --init
$ go get -u github.com/dvyukov/go-fuzz/go-fuzz github.com/dvyukov/go-fuzz/go-fuzz-build
$ go-fuzz-build && go-fuzz