add interface filter config (#502)

* add interface filter config

* Update config-sample.yaml

Co-authored-by: David Zhao <david@davidzhao.com>

* better description

Co-authored-by: David Zhao <david@davidzhao.com>

config-sample.yaml

@@ -61,6 +61,15 @@ rtc:
   #   low_quality: 500ms
   #   mid_quality: 1s
   #   high_quality: 1s
+  # # network interface filter. If the machine has more than one network interface and you'd like it to use or skip specific interfaces
+  # # both inclusion and exclusion filters can be used together. If neither is defined (default), all interfaces on the machine will be used.
+  # # If both of them are set, then only interfaces that satisfy both filters will be used.
+  # # If an interface is present in both lists, include takes precedence.
+  # interfaces:
+  #   includes:
+  #     - en0
+  #   excludes:
+  #     - docker0
 
 # when enabled, LiveKit will expose prometheus metrics on :6789/metrics
 # prometheus_port: 6789

pkg/config/config.go

@@ -46,15 +46,16 @@ type Config struct {
 }
 
 type RTCConfig struct {
-	UDPPort           uint32       `yaml:"udp_port,omitempty"`
-	TCPPort           uint32       `yaml:"tcp_port,omitempty"`
-	ICEPortRangeStart uint32       `yaml:"port_range_start,omitempty"`
-	ICEPortRangeEnd   uint32       `yaml:"port_range_end,omitempty"`
-	NodeIP            string       `yaml:"node_ip,omitempty"`
-	STUNServers       []string     `yaml:"stun_servers,omitempty"`
-	TURNServers       []TURNServer `yaml:"turn_servers,omitempty"`
-	UseExternalIP     bool         `yaml:"use_external_ip"`
-	UseICELite        bool         `yaml:"use_ice_lite,omitempty"`
+	UDPPort           uint32           `yaml:"udp_port,omitempty"`
+	TCPPort           uint32           `yaml:"tcp_port,omitempty"`
+	ICEPortRangeStart uint32           `yaml:"port_range_start,omitempty"`
+	ICEPortRangeEnd   uint32           `yaml:"port_range_end,omitempty"`
+	NodeIP            string           `yaml:"node_ip,omitempty"`
+	STUNServers       []string         `yaml:"stun_servers,omitempty"`
+	TURNServers       []TURNServer     `yaml:"turn_servers,omitempty"`
+	UseExternalIP     bool             `yaml:"use_external_ip"`
+	UseICELite        bool             `yaml:"use_ice_lite,omitempty"`
+	Interfaces        InterfacesConfig `yaml:"interfaces"`
 
 	// Number of packets to buffer for NACK
 	PacketBufferSize int `yaml:"packet_buffer_size,omitempty"`
@@ -92,6 +93,11 @@ type CongestionControlConfig struct {
 	ProbeMode      CongestionControlProbeMode `yaml:"padding_mode,omitempty"`
 }
 
+type InterfacesConfig struct {
+	Includes []string `yaml:"includes"`
+	Excludes []string `yaml:"excludes"`
+}
+
 type AudioConfig struct {
 	// minimum level to be considered active, 0-127, where 0 is loudest
 	ActiveLevel uint8 `yaml:"active_level"`

pkg/rtc/config.go

@@ -64,7 +64,7 @@ func NewWebRTCConfig(conf *config.Config, externalIP string) (*WebRTCConfig, err
 		LoggerFactory: logging.NewLoggerFactory(logger.GetLogger()),
 	}
 
-	if externalIP != "" {
+	if conf.RTC.UseExternalIP && externalIP != "" {
 		s.SetNAT1To1IPs([]string{externalIP}, webrtc.ICECandidateTypeHost)
 	}
 
@@ -180,6 +180,32 @@ func NewWebRTCConfig(conf *config.Config, externalIP string) (*WebRTCConfig, err
 		s.SetLite(true)
 	}
 
+	if len(rtcConf.Interfaces.Includes) != 0 || len(rtcConf.Interfaces.Excludes) != 0 {
+		includes := rtcConf.Interfaces.Includes
+		excludes := rtcConf.Interfaces.Excludes
+		s.SetInterfaceFilter(func(s string) bool {
+			//filter by include interfaces
+			if len(includes) > 0 {
+				for _, iface := range includes {
+					if iface == s {
+						return true
+					}
+				}
+				return false
+			}
+
+			// filter by exclude interfaces
+			if len(excludes) > 0 {
+				for _, iface := range excludes {
+					if iface == s {
+						return false
+					}
+				}
+			}
+			return true
+		})
+	}
+
 	return &WebRTCConfig{
 		Configuration: c,
 		SettingEngine: s,