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tailscale/net/tsaddr/tsaddr.go

53 lines
1.4 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tsaddr handles Tailscale-specific IPs and ranges.
package tsaddr
import (
"sync"
"inet.af/netaddr"
)
// ChromeOSVMRange returns the subset of the CGNAT IPv4 range used by
// ChromeOS to interconnect the host OS to containers and VMs. We
// avoid allocating Tailscale IPs from it, to avoid conflicts.
func ChromeOSVMRange() netaddr.IPPrefix {
chromeOSRange.Do(func() { mustPrefix(&chromeOSRange.v, "100.115.92.0/23") })
return chromeOSRange.v
}
var chromeOSRange oncePrefix
// CGNATRange returns the Carrier Grade NAT address range that
// is the superset range that Tailscale assigns out of.
// See https://tailscale.com/kb/1015/100.x-addresses.
// Note that Tailscale does not assign out of the ChromeOSVMRange.
func CGNATRange() netaddr.IPPrefix {
cgnatRange.Do(func() { mustPrefix(&cgnatRange.v, "100.64.0.0/10") })
return cgnatRange.v
}
var cgnatRange oncePrefix
// IsTailscaleIP reports whether ip is an IP address in a range that
// Tailscale assigns from.
func IsTailscaleIP(ip netaddr.IP) bool {
return CGNATRange().Contains(ip) && !ChromeOSVMRange().Contains(ip)
}
func mustPrefix(v *netaddr.IPPrefix, prefix string) {
var err error
*v, err = netaddr.ParseIPPrefix(prefix)
if err != nil {
panic(err)
}
}
type oncePrefix struct {
sync.Once
v netaddr.IPPrefix
}