nebula/inside.go

242 lines
7.6 KiB
Go

package nebula
import (
"sync/atomic"
"github.com/flynn/noise"
"github.com/sirupsen/logrus"
"github.com/slackhq/nebula/firewall"
"github.com/slackhq/nebula/header"
"github.com/slackhq/nebula/iputil"
"github.com/slackhq/nebula/udp"
)
func (f *Interface) consumeInsidePacket(packet []byte, fwPacket *firewall.Packet, nb, out []byte, q int, localCache firewall.ConntrackCache) {
err := newPacket(packet, false, fwPacket)
if err != nil {
f.l.WithField("packet", packet).Debugf("Error while validating outbound packet: %s", err)
return
}
// Ignore local broadcast packets
if f.dropLocalBroadcast && fwPacket.RemoteIP == f.localBroadcast {
return
}
// Ignore packets from self to self
if fwPacket.RemoteIP == f.myVpnIp {
return
}
// Ignore broadcast packets
if f.dropMulticast && isMulticast(fwPacket.RemoteIP) {
return
}
hostinfo := f.getOrHandshake(fwPacket.RemoteIP)
if hostinfo == nil {
if f.l.Level >= logrus.DebugLevel {
f.l.WithField("vpnIp", fwPacket.RemoteIP).
WithField("fwPacket", fwPacket).
Debugln("dropping outbound packet, vpnIp not in our CIDR or in unsafe routes")
}
return
}
ci := hostinfo.ConnectionState
if ci.ready == false {
// Because we might be sending stored packets, lock here to stop new things going to
// the packet queue.
ci.queueLock.Lock()
if !ci.ready {
hostinfo.cachePacket(f.l, header.Message, 0, packet, f.sendMessageNow, f.cachedPacketMetrics)
ci.queueLock.Unlock()
return
}
ci.queueLock.Unlock()
}
dropReason := f.firewall.Drop(packet, *fwPacket, false, hostinfo, f.caPool, localCache)
if dropReason == nil {
f.sendNoMetrics(header.Message, 0, ci, hostinfo, hostinfo.remote, packet, nb, out, q)
} else if f.l.Level >= logrus.DebugLevel {
hostinfo.logger(f.l).
WithField("fwPacket", fwPacket).
WithField("reason", dropReason).
Debugln("dropping outbound packet")
}
}
// getOrHandshake returns nil if the vpnIp is not routable
func (f *Interface) getOrHandshake(vpnIp iputil.VpnIp) *HostInfo {
//TODO: we can find contains without converting back to bytes
if f.hostMap.vpnCIDR.Contains(vpnIp.ToIP()) == false {
vpnIp = f.inside.RouteFor(vpnIp)
if vpnIp == 0 {
return nil
}
}
hostinfo, err := f.hostMap.PromoteBestQueryVpnIp(vpnIp, f)
//if err != nil || hostinfo.ConnectionState == nil {
if err != nil {
hostinfo, err = f.handshakeManager.pendingHostMap.QueryVpnIp(vpnIp)
if err != nil {
hostinfo = f.handshakeManager.AddVpnIp(vpnIp, f.initHostInfo)
}
}
ci := hostinfo.ConnectionState
if ci != nil && ci.eKey != nil && ci.ready {
return hostinfo
}
// Handshake is not ready, we need to grab the lock now before we start the handshake process
hostinfo.Lock()
defer hostinfo.Unlock()
// Double check, now that we have the lock
ci = hostinfo.ConnectionState
if ci != nil && ci.eKey != nil && ci.ready {
return hostinfo
}
// If we have already created the handshake packet, we don't want to call the function at all.
if !hostinfo.HandshakeReady {
ixHandshakeStage0(f, vpnIp, hostinfo)
// FIXME: Maybe make XX selectable, but probably not since psk makes it nearly pointless for us.
//xx_handshakeStage0(f, ip, hostinfo)
// If this is a static host, we don't need to wait for the HostQueryReply
// We can trigger the handshake right now
if _, ok := f.lightHouse.GetStaticHostList()[vpnIp]; ok {
select {
case f.handshakeManager.trigger <- vpnIp:
default:
}
}
}
return hostinfo
}
// initHostInfo is the init function to pass to (*HandshakeManager).AddVpnIP that
// will create the initial Noise ConnectionState
func (f *Interface) initHostInfo(hostinfo *HostInfo) {
hostinfo.ConnectionState = f.newConnectionState(f.l, true, noise.HandshakeIX, []byte{}, 0)
}
func (f *Interface) sendMessageNow(t header.MessageType, st header.MessageSubType, hostInfo *HostInfo, p, nb, out []byte) {
fp := &firewall.Packet{}
err := newPacket(p, false, fp)
if err != nil {
f.l.Warnf("error while parsing outgoing packet for firewall check; %v", err)
return
}
// check if packet is in outbound fw rules
dropReason := f.firewall.Drop(p, *fp, false, hostInfo, f.caPool, nil)
if dropReason != nil {
if f.l.Level >= logrus.DebugLevel {
f.l.WithField("fwPacket", fp).
WithField("reason", dropReason).
Debugln("dropping cached packet")
}
return
}
f.sendNoMetrics(header.Message, st, hostInfo.ConnectionState, hostInfo, hostInfo.remote, p, nb, out, 0)
}
// SendMessageToVpnIp handles real ip:port lookup and sends to the current best known address for vpnIp
func (f *Interface) SendMessageToVpnIp(t header.MessageType, st header.MessageSubType, vpnIp iputil.VpnIp, p, nb, out []byte) {
hostInfo := f.getOrHandshake(vpnIp)
if hostInfo == nil {
if f.l.Level >= logrus.DebugLevel {
f.l.WithField("vpnIp", vpnIp).
Debugln("dropping SendMessageToVpnIp, vpnIp not in our CIDR or in unsafe routes")
}
return
}
if !hostInfo.ConnectionState.ready {
// Because we might be sending stored packets, lock here to stop new things going to
// the packet queue.
hostInfo.ConnectionState.queueLock.Lock()
if !hostInfo.ConnectionState.ready {
hostInfo.cachePacket(f.l, t, st, p, f.sendMessageToVpnIp, f.cachedPacketMetrics)
hostInfo.ConnectionState.queueLock.Unlock()
return
}
hostInfo.ConnectionState.queueLock.Unlock()
}
f.sendMessageToVpnIp(t, st, hostInfo, p, nb, out)
return
}
func (f *Interface) sendMessageToVpnIp(t header.MessageType, st header.MessageSubType, hostInfo *HostInfo, p, nb, out []byte) {
f.send(t, st, hostInfo.ConnectionState, hostInfo, hostInfo.remote, p, nb, out)
}
func (f *Interface) send(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote *udp.Addr, p, nb, out []byte) {
f.messageMetrics.Tx(t, st, 1)
f.sendNoMetrics(t, st, ci, hostinfo, remote, p, nb, out, 0)
}
func (f *Interface) sendNoMetrics(t header.MessageType, st header.MessageSubType, ci *ConnectionState, hostinfo *HostInfo, remote *udp.Addr, p, nb, out []byte, q int) {
if ci.eKey == nil {
//TODO: log warning
return
}
var err error
//TODO: enable if we do more than 1 tun queue
//ci.writeLock.Lock()
c := atomic.AddUint64(&ci.atomicMessageCounter, 1)
//l.WithField("trace", string(debug.Stack())).Error("out Header ", &Header{Version, t, st, 0, hostinfo.remoteIndexId, c}, p)
out = header.Encode(out, header.Version, t, st, hostinfo.remoteIndexId, c)
f.connectionManager.Out(hostinfo.vpnIp)
// Query our LH if we haven't since the last time we've been rebound, this will cause the remote to punch against
// all our IPs and enable a faster roaming.
if t != header.CloseTunnel && hostinfo.lastRebindCount != f.rebindCount {
//NOTE: there is an update hole if a tunnel isn't used and exactly 256 rebinds occur before the tunnel is
// finally used again. This tunnel would eventually be torn down and recreated if this action didn't help.
f.lightHouse.QueryServer(hostinfo.vpnIp, f)
hostinfo.lastRebindCount = f.rebindCount
if f.l.Level >= logrus.DebugLevel {
f.l.WithField("vpnIp", hostinfo.vpnIp).Debug("Lighthouse update triggered for punch due to rebind counter")
}
}
out, err = ci.eKey.EncryptDanger(out, out, p, c, nb)
//TODO: see above note on lock
//ci.writeLock.Unlock()
if err != nil {
hostinfo.logger(f.l).WithError(err).
WithField("udpAddr", remote).WithField("counter", c).
WithField("attemptedCounter", c).
Error("Failed to encrypt outgoing packet")
return
}
err = f.writers[q].WriteTo(out, remote)
if err != nil {
hostinfo.logger(f.l).WithError(err).
WithField("udpAddr", remote).Error("Failed to write outgoing packet")
}
return
}
func isMulticast(ip iputil.VpnIp) bool {
// Class D multicast
if (((ip >> 24) & 0xff) & 0xf0) == 0xe0 {
return true
}
return false
}