Ensure mutex is unlocked when adding remote IP. (#406)

Currently, if you use the remote allow list config, as soon as you attempt to create a tunnel to a node that has a blocked IP address, a mutex is locked and never unlocked. This happens even if the node has an allowed remote IP address in addition to the blocked remote IP address.

This pull request ensures that the lighthouse mutex is unlocked whenever we attempt to add a remote IP.

lighthouse.go

@@ -172,9 +172,9 @@ func (lh *LightHouse) AddRemote(vpnIP uint32, toIp *udpAddr, static bool) {
 	}
 
 	lh.Lock()
+	defer lh.Unlock()
 	for _, v := range lh.addrMap[vpnIP] {
 		if v.Equals(toIp) {
-			lh.Unlock()
 			return
 		}
 	}
@@ -190,7 +190,6 @@ func (lh *LightHouse) AddRemote(vpnIP uint32, toIp *udpAddr, static bool) {
 		lh.staticList[vpnIP] = struct{}{}
 	}
 	lh.addrMap[vpnIP] = append(lh.addrMap[vpnIP], *toIp)
-	lh.Unlock()
 }
 
 func (lh *LightHouse) AddRemoteAndReset(vpnIP uint32, toIp *udpAddr) {

lighthouse_test.go

@@ -124,6 +124,35 @@ func BenchmarkLighthouseHandleRequest(b *testing.B) {
 	})
 }
 
+func Test_lhRemoteAllowList(t *testing.T) {
+	c := NewConfig()
+	c.Settings["remoteallowlist"] = map[interface{}]interface{}{
+		"10.20.0.0/12": false,
+	}
+	allowList, err := c.GetAllowList("remoteallowlist", false)
+	assert.Nil(t, err)
+
+	lh1 := "10.128.0.2"
+	lh1IP := net.ParseIP(lh1)
+
+	udpServer, _ := NewListener("0.0.0.0", 0, true)
+
+	lh := NewLightHouse(true, 1, []uint32{ip2int(lh1IP)}, 10, 10003, udpServer, false, 1, false)
+	lh.SetRemoteAllowList(allowList)
+
+	remote1 := "10.20.0.3"
+	remote1IP := net.ParseIP(remote1)
+	lh.AddRemote(ip2int(remote1IP), NewUDPAddr(ip2int(remote1IP), uint16(4242)), true)
+	assert.Nil(t, lh.addrMap[ip2int(remote1IP)])
+
+	remote2 := "10.128.0.3"
+	remote2IP := net.ParseIP(remote2)
+	remote2UDPAddr := NewUDPAddr(ip2int(remote2IP), uint16(4242))
+
+	lh.AddRemote(ip2int(remote2IP), remote2UDPAddr, true)
+	assert.Equal(t, remote2UDPAddr, &lh.addrMap[ip2int(remote2IP)][0])
+}
+
 //func NewLightHouse(amLighthouse bool, myIp uint32, ips []string, interval int, nebulaPort int, pc *udpConn, punchBack bool) *LightHouse {
 
 /*