mirror of
https://github.com/juanfont/headscale.git
synced 2024-11-26 17:03:06 +00:00
141 lines
3.3 KiB
Go
141 lines
3.3 KiB
Go
// Codehere is mostly taken from github.com/tailscale/tailscale
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package headscale
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import (
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"crypto/rand"
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"encoding/json"
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"fmt"
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"io"
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"golang.org/x/crypto/nacl/box"
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"inet.af/netaddr"
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"tailscale.com/types/wgkey"
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)
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// Error is used to compare errors as per https://dave.cheney.net/2016/04/07/constant-errors
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type Error string
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func (e Error) Error() string { return string(e) }
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func decode(msg []byte, v interface{}, pubKey *wgkey.Key, privKey *wgkey.Private) error {
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return decodeMsg(msg, v, pubKey, privKey)
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}
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func decodeMsg(msg []byte, v interface{}, pubKey *wgkey.Key, privKey *wgkey.Private) error {
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decrypted, err := decryptMsg(msg, pubKey, privKey)
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if err != nil {
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return err
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}
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// fmt.Println(string(decrypted))
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if err := json.Unmarshal(decrypted, v); err != nil {
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return fmt.Errorf("response: %v", err)
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}
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return nil
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}
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func decryptMsg(msg []byte, pubKey *wgkey.Key, privKey *wgkey.Private) ([]byte, error) {
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var nonce [24]byte
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if len(msg) < len(nonce)+1 {
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return nil, fmt.Errorf("response missing nonce, len=%d", len(msg))
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}
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copy(nonce[:], msg)
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msg = msg[len(nonce):]
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pub, pri := (*[32]byte)(pubKey), (*[32]byte)(privKey)
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decrypted, ok := box.Open(nil, msg, &nonce, pub, pri)
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if !ok {
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return nil, fmt.Errorf("cannot decrypt response")
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}
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return decrypted, nil
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}
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func encode(v interface{}, pubKey *wgkey.Key, privKey *wgkey.Private) ([]byte, error) {
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b, err := json.Marshal(v)
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if err != nil {
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return nil, err
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}
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return encodeMsg(b, pubKey, privKey)
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}
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func encodeMsg(b []byte, pubKey *wgkey.Key, privKey *wgkey.Private) ([]byte, error) {
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var nonce [24]byte
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if _, err := io.ReadFull(rand.Reader, nonce[:]); err != nil {
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panic(err)
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}
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pub, pri := (*[32]byte)(pubKey), (*[32]byte)(privKey)
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msg := box.Seal(nonce[:], b, &nonce, pub, pri)
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return msg, nil
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}
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func (h *Headscale) getAvailableIP() (*netaddr.IP, error) {
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ipPrefix := h.cfg.IPPrefix
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usedIps, err := h.getUsedIPs()
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if err != nil {
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return nil, err
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}
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// Get the first IP in our prefix
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ip := ipPrefix.IP()
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for {
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if !ipPrefix.Contains(ip) {
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return nil, fmt.Errorf("could not find any suitable IP in %s", ipPrefix)
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}
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// Some OS (including Linux) does not like when IPs ends with 0 or 255, which
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// is typically called network or broadcast. Lets avoid them and continue
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// to look when we get one of those traditionally reserved IPs.
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ipRaw := ip.As4()
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if ipRaw[3] == 0 || ipRaw[3] == 255 {
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ip = ip.Next()
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continue
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}
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if ip.IsZero() &&
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ip.IsLoopback() {
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ip = ip.Next()
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continue
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}
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if !containsIPs(usedIps, ip) {
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return &ip, nil
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}
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ip = ip.Next()
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}
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}
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func (h *Headscale) getUsedIPs() ([]netaddr.IP, error) {
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var addresses []string
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h.db.Model(&Machine{}).Pluck("ip_address", &addresses)
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ips := make([]netaddr.IP, len(addresses))
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for index, addr := range addresses {
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if addr != "" {
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ip, err := netaddr.ParseIP(addr)
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if err != nil {
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return nil, fmt.Errorf("failed to parse ip from database, %w", err)
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}
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ips[index] = ip
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}
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}
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return ips, nil
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}
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func containsIPs(ips []netaddr.IP, ip netaddr.IP) bool {
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for _, v := range ips {
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if v == ip {
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return true
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}
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}
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return false
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}
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