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@@ -0,0 +1,282 @@
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+package udp
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+
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+import (
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+ "fmt"
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+ "encoding/json"
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+ "net"
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+ "os"
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+ "strings"
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+ "sync"
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+ "syscall"
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+
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+ "github.com/coreos/rudder/Godeps/_workspace/src/github.com/docker/libcontainer/netlink"
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+ log "github.com/coreos/rudder/Godeps/_workspace/src/github.com/golang/glog"
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+
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+ "github.com/coreos/rudder/backend"
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+ "github.com/coreos/rudder/pkg/ip"
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+ "github.com/coreos/rudder/pkg/task"
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+ "github.com/coreos/rudder/subnet"
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+)
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+
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+const (
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+ encapOverhead = 28 // 20 bytes IP hdr + 8 bytes UDP hdr
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+ defaultPort = 8285
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+)
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+
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+type UdpBackend struct {
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+ sm *subnet.SubnetManager
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+ rawCfg json.RawMessage
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+ cfg struct {
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+ Port int
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+ }
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+ ctl *os.File
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+ ctl2 *os.File
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+ tun *os.File
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+ conn *net.UDPConn
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+ mtu int
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+ tunNet ip.IP4Net
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+ stop chan bool
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+ wg sync.WaitGroup
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+}
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+
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+func New(sm *subnet.SubnetManager, config json.RawMessage) backend.Backend {
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+ be := UdpBackend{
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+ sm: sm,
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+ rawCfg: config,
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+ stop: make(chan bool),
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+ }
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+ be.cfg.Port = defaultPort
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+ return &be
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+}
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+
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+func (m *UdpBackend) Init(extIface *net.Interface, extIP net.IP, ipMasq bool) (*backend.SubnetDef, error) {
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+ // Parse our configuration
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+ if len(m.rawCfg) > 0 {
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+ if err := json.Unmarshal(m.rawCfg, &m.cfg); err != nil {
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+ return nil, fmt.Errorf("error decoding UDP backend config: %v", err)
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+ }
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+ }
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+
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+ // Acquire the lease form subnet manager
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+ attrs := subnet.BaseAttrs{
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+ PublicIP: ip.FromIP(extIP),
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+ }
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+
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+ sn, err := m.sm.AcquireLease(attrs.PublicIP, &attrs, m.stop)
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+ if err != nil {
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+ if err == task.ErrCanceled {
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+ return nil, err
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+ } else {
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+ return nil, fmt.Errorf("failed to acquire lease: %v", err)
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+ }
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+ }
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+
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+ // Tunnel's subnet is that of the whole overlay network (e.g. /16)
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+ // and not that of the individual host (e.g. /24)
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+ m.tunNet = ip.IP4Net{
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+ IP: sn.IP,
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+ PrefixLen: m.sm.GetConfig().Network.PrefixLen,
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+ }
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+
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+ // TUN MTU will be smaller b/c of encap (IP+UDP hdrs)
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+ m.mtu = extIface.MTU - encapOverhead
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+
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+ if err = m.initTun(ipMasq); err != nil {
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+ return nil, err
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+ }
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+
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+ m.conn, err = net.ListenUDP("udp4", &net.UDPAddr{Port: m.cfg.Port})
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+ if err != nil {
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+ return nil, fmt.Errorf("failed to start listening on UDP socket: %v", err)
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+ }
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+
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+
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+ m.ctl, m.ctl2, err = newCtlSockets()
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+ if err != nil {
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+ return nil, fmt.Errorf("failed to create control socket: %v", err)
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+ }
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+
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+ return &backend.SubnetDef{
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+ Net: sn,
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+ MTU: m.mtu,
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+ }, nil
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+}
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+
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+func (m *UdpBackend) Run() {
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+ // one for each goroutine below
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+ m.wg.Add(2)
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+
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+ go func() {
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+ runCProxy(m.tun, m.conn, m.ctl2, m.tunNet.IP, m.mtu)
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+ m.wg.Done()
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+ }()
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+
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+ go func() {
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+ m.sm.LeaseRenewer(m.stop)
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+ m.wg.Done()
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+ }()
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+
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+ m.monitorEvents()
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+
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+ m.wg.Wait()
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+}
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+
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+func (m *UdpBackend) Stop() {
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+ if m.ctl != nil {
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+ stopProxy(m.ctl)
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+ }
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+
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+ close(m.stop)
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+}
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+
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+func (m *UdpBackend) Name() string {
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+ return "UDP"
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+}
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+
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+func newCtlSockets() (*os.File, *os.File, error) {
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+ fds, err := syscall.Socketpair(syscall.AF_UNIX, syscall.SOCK_SEQPACKET, 0)
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+ if err != nil {
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+ return nil, nil, err
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+ }
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+
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+ f1 := os.NewFile(uintptr(fds[0]), "ctl")
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+ f2 := os.NewFile(uintptr(fds[1]), "ctl")
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+ return f1, f2, nil
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+}
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+
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+func (m *UdpBackend) initTun(ipMasq bool) error {
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+ var tunName string
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+ var err error
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+
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+ m.tun, tunName, err = ip.OpenTun("rudder%d")
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+ if err != nil {
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+ return fmt.Errorf("Failed to open TUN device: %v", err)
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+ }
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+
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+ err = configureIface(tunName, m.tunNet, m.mtu)
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+ if err != nil {
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+ return err
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+ }
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+
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+ if ipMasq {
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+ err = setupIpMasq(m.tunNet.Network(), tunName)
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+ if err != nil {
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+ return err
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+ }
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+ }
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+
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+ return nil
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+}
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+
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+func configureIface(ifname string, ipn ip.IP4Net, mtu int) error {
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+ iface, err := net.InterfaceByName(ifname)
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+ if err != nil {
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+ return fmt.Errorf("failed to lookup interface %v", ifname)
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+ }
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+
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+ n := ipn.ToIPNet()
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+ err = netlink.NetworkLinkAddIp(iface, n.IP, n)
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+ if err != nil {
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+ return fmt.Errorf("failed to add IP address %v to %v: %v", n.IP, ifname, err)
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+ }
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+
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+ err = netlink.NetworkSetMTU(iface, mtu)
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+ if err != nil {
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+ return fmt.Errorf("failed to set MTU for %v: %v", ifname, err)
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+ }
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+
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+ err = netlink.NetworkLinkUp(iface)
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+ if err != nil {
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+ return fmt.Errorf("failed to set interface %v to UP state: %v", ifname, err)
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+ }
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+
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+ // explicitly add a route since there might be a route for a subnet already
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+ // installed by Docker and then it won't get auto added
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+ err = netlink.AddRoute(ipn.Network().String(), "", "", ifname)
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+ if err != nil && err != syscall.EEXIST {
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+ return fmt.Errorf("Failed to add route (%v -> %v): %v", ipn.Network().String(), ifname, err)
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+ }
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+
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+ return nil
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+}
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+
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+func setupIpMasq(ipn ip.IP4Net, iface string) error {
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+ ipt, err := ip.NewIPTables()
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+ if err != nil {
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+ return fmt.Errorf("failed to setup IP Masquerade. iptables was not found")
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+ }
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+
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+ err = ipt.ClearChain("nat", "RUDDER")
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+ if err != nil {
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+ return fmt.Errorf("Failed to create/clear RUDDER chain in NAT table: %v", err)
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+ }
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+
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+ rules := [][]string{
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+ // This rule makes sure we don't NAT traffic within overlay network (e.g. coming out of docker0)
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+ []string{ "RUDDER", "-d", ipn.String(), "-j", "ACCEPT" },
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+ // This rule makes sure we don't NAT multicast traffic within overlay network
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+ []string{ "RUDDER", "-d", "224.0.0.0/4", "-j", "ACCEPT" },
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+ // This rule will NAT everything originating from our overlay network and
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+ []string{ "RUDDER", "!", "-o", iface, "-j", "MASQUERADE" },
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+ // This rule will take everything coming from overlay and sent it to RUDDER chain
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+ []string{ "POSTROUTING", "-s", ipn.String(), "-j", "RUDDER" },
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+ }
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+
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+ for _, args := range rules {
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+ log.Info("Adding iptables rule: ", strings.Join(args, " "))
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+
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+ err = ipt.AppendUnique("nat", args...)
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+ if err != nil {
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+ return fmt.Errorf("Failed to insert IP masquerade rule: %v", err)
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+ }
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+ }
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+
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+ return nil
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+}
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+
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+func (m *UdpBackend) monitorEvents() {
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+ log.Info("Watching for new subnet leases")
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+
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+ evts := make(chan subnet.EventBatch)
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+
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+ m.wg.Add(1)
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+ go func() {
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+ m.sm.WatchLeases(evts, m.stop)
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+ m.wg.Done()
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+ }()
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+
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+ for {
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+ select {
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+ case evtBatch := <-evts:
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+ m.processSubnetEvents(evtBatch)
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+
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+ case <-m.stop:
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+ return
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+ }
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+ }
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+}
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+
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+func (m *UdpBackend) processSubnetEvents(batch subnet.EventBatch) {
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+ for _, evt := range batch {
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+ switch evt.Type {
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+ case subnet.SubnetAdded:
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+ log.Info("Subnet added: ", evt.Lease.Network)
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+
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+ var attrs subnet.BaseAttrs
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+ if err := json.Unmarshal([]byte(evt.Lease.Data), &attrs); err != nil {
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+ log.Error("Error decoding subnet lease JSON: ", err)
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+ continue
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+ }
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+
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+ setRoute(m.ctl, evt.Lease.Network, attrs.PublicIP, m.cfg.Port)
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+
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+ case subnet.SubnetRemoved:
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+ log.Info("Subnet removed: ", evt.Lease.Network)
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+
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+ removeRoute(m.ctl, evt.Lease.Network)
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+
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+ default:
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+ log.Error("Internal error: unknown event type: ", int(evt.Type))
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+ }
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+ }
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+}
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