Serge Bazanski | de0330a | 2020-07-30 20:48:48 +0200 | [diff] [blame] | 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "net" |
| 6 | "strings" |
| 7 | |
| 8 | "github.com/golang/glog" |
| 9 | ) |
| 10 | |
| 11 | type packetFrom struct { |
| 12 | addr net.Addr |
| 13 | data []byte |
| 14 | } |
| 15 | |
| 16 | func (s *service) runProxy(ctx context.Context, updates chan *lockUpdate, laserAddr net.Addr, laserNet, clientNet net.PacketConn) { |
| 17 | glog.Infof("Proxy starting... (laser: %v, laser network: %v, client network: %v)", laserAddr, laserNet, clientNet) |
| 18 | |
| 19 | |
| 20 | pipe := func(conn net.PacketConn, C chan *packetFrom) { |
| 21 | for { |
| 22 | buf := make([]byte, 1500) |
| 23 | n, addr, err := conn.ReadFrom(buf) |
| 24 | if err != nil { |
| 25 | glog.Errorf("pipe failed: %v", err) |
| 26 | } |
| 27 | C <- &packetFrom{ addr, buf[:n] } |
| 28 | } |
| 29 | } |
| 30 | |
| 31 | laserC := make(chan *packetFrom) |
| 32 | go pipe(laserNet, laserC) |
| 33 | clientC := make(chan *packetFrom) |
| 34 | go pipe(clientNet, clientC) |
| 35 | |
| 36 | var allowedClient string |
| 37 | var curClient *net.Addr |
| 38 | for { |
| 39 | select { |
| 40 | case <-ctx.Done(): |
| 41 | err := ctx.Err() |
| 42 | glog.Errorf("Proxy stopped: %v", err) |
| 43 | return |
| 44 | case u := <-updates: |
| 45 | allowedClient = u.addr |
| 46 | glog.Infof("New allowed client: %q", allowedClient) |
| 47 | case p := <-laserC: |
| 48 | s.lockCtrl <- &lockCtrl{ |
| 49 | bump: &lockCtrlBump{}, |
| 50 | } |
| 51 | if curClient == nil { |
| 52 | glog.Warningf("Packet from laser without client connected, dropping.") |
| 53 | break |
| 54 | } |
| 55 | clientNet.WriteTo(p.data, *curClient) |
| 56 | case p := <-clientC: |
| 57 | s.lockCtrl <- &lockCtrl{ |
| 58 | bump: &lockCtrlBump{}, |
| 59 | } |
| 60 | if strings.Split(p.addr.String(), ":")[0] == allowedClient { |
| 61 | curClient = &p.addr |
| 62 | laserNet.WriteTo(p.data, laserAddr) |
| 63 | } else { |
| 64 | glog.Infof("Rejecting packet from %s", p.addr.String()) |
| 65 | } |
| 66 | } |
| 67 | } |
| 68 | } |
| 69 | |