mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-26 03:25:35 +00:00
64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
// Copyright 2019 Tailscale & 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 magicsock
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
)
|
|
|
|
// DerpMagicIP is a fake WireGuard endpoint IP address that means
|
|
// to use DERP. When used, the port number of the WireGuard endpoint
|
|
// is the DERP server number to use.
|
|
//
|
|
// Mnemonic: 3.3.40 are numbers above the keys D, E, R, P.
|
|
const DerpMagicIP = "127.3.3.40"
|
|
|
|
var derpMagicIP = net.ParseIP(DerpMagicIP).To4()
|
|
|
|
var (
|
|
derpHostOfIndex = map[int]string{} // node ID index (fake port number) -> hostname
|
|
derpIndexOfHost = map[string]int{} // derpHostOfIndex reversed
|
|
derpNodeID []int
|
|
)
|
|
|
|
const (
|
|
derpUSNY = 1
|
|
derpUSSF = 2
|
|
derpSG = 3
|
|
derpDE = 4
|
|
)
|
|
|
|
func init() {
|
|
addDerper(derpUSNY, "derp1.tailscale.com")
|
|
addDerper(derpUSSF, "derp2.tailscale.com")
|
|
addDerper(derpSG, "derp3.tailscale.com")
|
|
addDerper(derpDE, "derp4.tailscale.com")
|
|
}
|
|
|
|
func addDerper(i int, host string) {
|
|
if other, dup := derpHostOfIndex[i]; dup {
|
|
panic(fmt.Sprintf("duplicate DERP index %v (host %q and %q)", i, other, host))
|
|
}
|
|
if other, dup := derpIndexOfHost[host]; dup {
|
|
panic(fmt.Sprintf("duplicate DERP host %q (index %v and %v)", host, other, i))
|
|
}
|
|
derpHostOfIndex[i] = host
|
|
derpIndexOfHost[host] = i
|
|
derpNodeID = append(derpNodeID, i)
|
|
}
|
|
|
|
// derpHost returns the hostname of a DERP server index (a fake port
|
|
// number used with derpMagicIP).
|
|
func derpHost(i int) string {
|
|
if h, ok := derpHostOfIndex[i]; ok {
|
|
return h
|
|
}
|
|
if 1 <= i && i <= 64<<10 {
|
|
return fmt.Sprintf("derp%v.tailscale.com", i)
|
|
}
|
|
return ""
|
|
}
|