Merge pull request 'hosts' (#9) from hosts into develop

Reviewed-on: #9

config/builder.go

@@ -72,7 +72,7 @@ func (c Configuration) Build() (*proxy.Proxy, error) {
 func buildTcp(p *proxy.Proxy, peer Peer, g func() proxy.MacGenerator, v func() proxy.MacVerifier) error {
 	if peer.RemoteHost != "" {
 		f, err := tcp.InitiateFlow(
-			fmt.Sprintf("%s:", peer.LocalHost),
+			func() string { return fmt.Sprintf("%s:", peer.GetLocalHost()) },
 			fmt.Sprintf("%s:%d", peer.RemoteHost, peer.RemotePort),
 		)
 
@@ -86,7 +86,7 @@ func buildTcp(p *proxy.Proxy, peer Peer, g func() proxy.MacGenerator, v func() p
 		return nil
 	}
 
-	err := tcp.NewListener(p, fmt.Sprintf("%s:%d", peer.LocalHost, peer.LocalPort), v, g)
+	err := tcp.NewListener(p, fmt.Sprintf("%s:%d", peer.GetLocalHost(), peer.LocalPort), v, g)
 	if err != nil {
 		return err
 	}
@@ -107,7 +107,7 @@ func buildUdp(p *proxy.Proxy, peer Peer, g func() proxy.MacGenerator, v func() p
 
 	if peer.RemoteHost != "" {
 		f, err := udp.InitiateFlow(
-			fmt.Sprintf("%s:", peer.LocalHost),
+			func() string { return fmt.Sprintf("%s:", peer.GetLocalHost()) },
 			fmt.Sprintf("%s:%d", peer.RemoteHost, peer.RemotePort),
 			v(),
 			g(),
@@ -125,7 +125,7 @@ func buildUdp(p *proxy.Proxy, peer Peer, g func() proxy.MacGenerator, v func() p
 		return nil
 	}
 
-	err := udp.NewListener(p, fmt.Sprintf("%s:%d", peer.LocalHost, peer.LocalPort), v, g, c)
+	err := udp.NewListener(p, fmt.Sprintf("%s:%d", peer.GetLocalHost(), peer.LocalPort), v, g, c)
 	if err != nil {
 		return err
 	}

config/config.go

@@ -1,9 +1,37 @@
 package config
 
-import "github.com/go-playground/validator/v10"
+import (
+	"github.com/go-playground/validator/v10"
+	"log"
+	"net"
+	"strings"
+)
 
 var v = validator.New()
 
+func init() {
+	if err := v.RegisterValidation("iface", func(fl validator.FieldLevel) bool {
+		name, ok := fl.Field().Interface().(string)
+		if ok {
+			ifaces, err := net.Interfaces()
+			if err != nil {
+				log.Printf("error getting interfaces: %v", err)
+				return false
+			}
+
+			for _, i := range ifaces {
+				if i.Name == name {
+					return true
+				}
+			}
+		}
+
+		return false
+	}); err != nil {
+		panic(err)
+	}
+}
+
 type Configuration struct {
 	Host  Host
 	Peers []Peer `validate:"dive"`
@@ -19,7 +47,7 @@ type Host struct {
 type Peer struct {
 	Method string `validate:"oneof=TCP UDP"`
 
-	LocalHost string `validate:"omitempty,ip"`
+	LocalHost string `validate:"omitempty,ip|iface"`
 	LocalPort uint   `validate:"max=65535"`
 
 	RemoteHost string `validate:"required_with=RemotePort,omitempty,fqdn|ip"`
@@ -32,6 +60,33 @@ type Peer struct {
 	RetryWait uint
 }
 
+func (p Peer) GetLocalHost() string {
+	if err := v.Var(p.LocalHost, "ip"); err == nil {
+		return p.LocalHost
+	}
+
+	iface, err := net.InterfaceByName(p.LocalHost)
+	if err != nil {
+		panic(err)
+	}
+
+	if iface != nil {
+		addrs, err := iface.Addrs()
+		if err != nil {
+			panic(err)
+		}
+
+		if len(addrs) > 0 {
+			addr := addrs[0].String()
+			addr = strings.Split(addr, "/")[0]
+			log.Printf("resolved interface `%s` to `%v`", p.LocalHost, addr)
+			return addr
+		}
+	}
+
+	return "invalid"
+}
+
 func (c Configuration) Validate() error {
 	return v.Struct(c)
 }

tcp/flow.go

@@ -22,7 +22,7 @@ type Conn interface {
 }
 
 type InitiatedFlow struct {
-	Local  string
+	Local  func() string
 	Remote string
 
 	mu sync.RWMutex
@@ -31,7 +31,7 @@ type InitiatedFlow struct {
 }
 
 func (f *InitiatedFlow) String() string {
-	return fmt.Sprintf("TcpOutbound{%v -> %v}", f.Local, f.Remote)
+	return fmt.Sprintf("TcpOutbound{%v -> %v}", f.Local(), f.Remote)
 }
 
 type Flow struct {
@@ -43,7 +43,7 @@ func (f Flow) String() string {
 	return fmt.Sprintf("TcpInbound{%v -> %v}", f.conn.RemoteAddr(), f.conn.LocalAddr())
 }
 
-func InitiateFlow(local, remote string) (*InitiatedFlow, error) {
+func InitiateFlow(local func() string, remote string) (*InitiatedFlow, error) {
 	f := InitiatedFlow{
 		Local:  local,
 		Remote: remote,
@@ -60,7 +60,7 @@ func (f *InitiatedFlow) Reconnect() error {
 		return nil
 	}
 
-	localAddr, err := net.ResolveTCPAddr("tcp", f.Local)
+	localAddr, err := net.ResolveTCPAddr("tcp", f.Local())
 	if err != nil {
 		return err
 	}

udp/flow.go

@@ -23,7 +23,7 @@ type PacketConn interface {
 }
 
 type InitiatedFlow struct {
-	Local  string
+	Local  func() string
 	Remote string
 
 	g         proxy.MacGenerator
@@ -34,7 +34,7 @@ type InitiatedFlow struct {
 }
 
 func (f *InitiatedFlow) String() string {
-	return fmt.Sprintf("UdpOutbound{%v -> %v}", f.Local, f.Remote)
+	return fmt.Sprintf("UdpOutbound{%v -> %v}", f.Local(), f.Remote)
 }
 
 type Flow struct {
@@ -55,7 +55,8 @@ func (f Flow) String() string {
 }
 
 func InitiateFlow(
-	local, remote string,
+	local func() string,
+	remote string,
 	v proxy.MacVerifier,
 	g proxy.MacGenerator,
 	c Congestion,
@@ -88,7 +89,7 @@ func (f *InitiatedFlow) Reconnect() error {
 		return nil
 	}
 
-	localAddr, err := net.ResolveUDPAddr("udp", f.Local)
+	localAddr, err := net.ResolveUDPAddr("udp", f.Local())
 	if err != nil {
 		return err
 	}