Style: code style

listener/redir/tcp.go

@@ -0,0 +1,56 @@
+package redir
+
+import (
+	"net"
+
+	"github.com/Dreamacro/clash/adapter/inbound"
+	C "github.com/Dreamacro/clash/constant"
+)
+
+type Listener struct {
+	net.Listener
+	address string
+	closed  bool
+}
+
+func New(addr string, in chan<- C.ConnContext) (*Listener, error) {
+	l, err := net.Listen("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+	rl := &Listener{l, addr, false}
+
+	go func() {
+		for {
+			c, err := l.Accept()
+			if err != nil {
+				if rl.closed {
+					break
+				}
+				continue
+			}
+			go handleRedir(c, in)
+		}
+	}()
+
+	return rl, nil
+}
+
+func (l *Listener) Close() {
+	l.closed = true
+	l.Listener.Close()
+}
+
+func (l *Listener) Address() string {
+	return l.address
+}
+
+func handleRedir(conn net.Conn, in chan<- C.ConnContext) {
+	target, err := parserPacket(conn)
+	if err != nil {
+		conn.Close()
+		return
+	}
+	conn.(*net.TCPConn).SetKeepAlive(true)
+	in <- inbound.NewSocket(target, conn, C.REDIR)
+}

listener/redir/tcp_darwin.go

@@ -0,0 +1,58 @@
+package redir
+
+import (
+	"net"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+func parserPacket(c net.Conn) (socks5.Addr, error) {
+	const (
+		PfInout     = 0
+		PfIn        = 1
+		PfOut       = 2
+		IOCOut      = 0x40000000
+		IOCIn       = 0x80000000
+		IOCInOut    = IOCIn | IOCOut
+		IOCPARMMask = 0x1FFF
+		LEN         = 4*16 + 4*4 + 4*1
+		// #define	_IOC(inout,group,num,len) (inout | ((len & IOCPARMMask) << 16) | ((group) << 8) | (num))
+		// #define	_IOWR(g,n,t)	_IOC(IOCInOut,	(g), (n), sizeof(t))
+		// #define DIOCNATLOOK		_IOWR('D', 23, struct pfioc_natlook)
+		DIOCNATLOOK = IOCInOut | ((LEN & IOCPARMMask) << 16) | ('D' << 8) | 23
+	)
+
+	fd, err := syscall.Open("/dev/pf", 0, syscall.O_RDONLY)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.Close(fd)
+
+	nl := struct { // struct pfioc_natlook
+		saddr, daddr, rsaddr, rdaddr       [16]byte
+		sxport, dxport, rsxport, rdxport   [4]byte
+		af, proto, protoVariant, direction uint8
+	}{
+		af:        syscall.AF_INET,
+		proto:     syscall.IPPROTO_TCP,
+		direction: PfOut,
+	}
+	saddr := c.RemoteAddr().(*net.TCPAddr)
+	daddr := c.LocalAddr().(*net.TCPAddr)
+	copy(nl.saddr[:], saddr.IP)
+	copy(nl.daddr[:], daddr.IP)
+	nl.sxport[0], nl.sxport[1] = byte(saddr.Port>>8), byte(saddr.Port)
+	nl.dxport[0], nl.dxport[1] = byte(daddr.Port>>8), byte(daddr.Port)
+
+	if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, uintptr(fd), DIOCNATLOOK, uintptr(unsafe.Pointer(&nl))); errno != 0 {
+		return nil, errno
+	}
+
+	addr := make([]byte, 1+net.IPv4len+2)
+	addr[0] = socks5.AtypIPv4
+	copy(addr[1:1+net.IPv4len], nl.rdaddr[:4])
+	copy(addr[1+net.IPv4len:], nl.rdxport[:2])
+	return addr, nil
+}

listener/redir/tcp_freebsd.go

@@ -0,0 +1,52 @@
+package redir
+
+import (
+	"errors"
+	"net"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+const (
+	SO_ORIGINAL_DST      = 80 // from linux/include/uapi/linux/netfilter_ipv4.h
+	IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
+)
+
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
+	c, ok := conn.(*net.TCPConn)
+	if !ok {
+		return nil, errors.New("only work with TCP connection")
+	}
+
+	rc, err := c.SyscallConn()
+	if err != nil {
+		return nil, err
+	}
+
+	var addr socks5.Addr
+
+	rc.Control(func(fd uintptr) {
+		addr, err = getorigdst(fd)
+	})
+
+	return addr, err
+}
+
+// Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+func getorigdst(fd uintptr) (socks5.Addr, error) {
+	raw := syscall.RawSockaddrInet4{}
+	siz := unsafe.Sizeof(raw)
+	_, _, err := syscall.Syscall6(syscall.SYS_GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0)
+	if err != 0 {
+		return nil, err
+	}
+
+	addr := make([]byte, 1+net.IPv4len+2)
+	addr[0] = socks5.AtypIPv4
+	copy(addr[1:1+net.IPv4len], raw.Addr[:])
+	port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
+	addr[1+net.IPv4len], addr[1+net.IPv4len+1] = port[0], port[1]
+	return addr, nil
+}

listener/redir/tcp_linux.go

@@ -0,0 +1,51 @@
+package redir
+
+import (
+	"errors"
+	"net"
+	"syscall"
+	"unsafe"
+
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+const (
+	SO_ORIGINAL_DST      = 80 // from linux/include/uapi/linux/netfilter_ipv4.h
+	IP6T_SO_ORIGINAL_DST = 80 // from linux/include/uapi/linux/netfilter_ipv6/ip6_tables.h
+)
+
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
+	c, ok := conn.(*net.TCPConn)
+	if !ok {
+		return nil, errors.New("only work with TCP connection")
+	}
+
+	rc, err := c.SyscallConn()
+	if err != nil {
+		return nil, err
+	}
+
+	var addr socks5.Addr
+
+	rc.Control(func(fd uintptr) {
+		addr, err = getorigdst(fd)
+	})
+
+	return addr, err
+}
+
+// Call getorigdst() from linux/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+func getorigdst(fd uintptr) (socks5.Addr, error) {
+	raw := syscall.RawSockaddrInet4{}
+	siz := unsafe.Sizeof(raw)
+	if err := socketcall(GETSOCKOPT, fd, syscall.IPPROTO_IP, SO_ORIGINAL_DST, uintptr(unsafe.Pointer(&raw)), uintptr(unsafe.Pointer(&siz)), 0); err != nil {
+		return nil, err
+	}
+
+	addr := make([]byte, 1+net.IPv4len+2)
+	addr[0] = socks5.AtypIPv4
+	copy(addr[1:1+net.IPv4len], raw.Addr[:])
+	port := (*[2]byte)(unsafe.Pointer(&raw.Port)) // big-endian
+	addr[1+net.IPv4len], addr[1+net.IPv4len+1] = port[0], port[1]
+	return addr, nil
+}

listener/redir/tcp_linux_386.go

@@ -0,0 +1,17 @@
+package redir
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const GETSOCKOPT = 15 // https://golang.org/src/syscall/syscall_linux_386.go#L183
+
+func socketcall(call, a0, a1, a2, a3, a4, a5 uintptr) error {
+	var a [6]uintptr
+	a[0], a[1], a[2], a[3], a[4], a[5] = a0, a1, a2, a3, a4, a5
+	if _, _, errno := syscall.Syscall6(syscall.SYS_SOCKETCALL, call, uintptr(unsafe.Pointer(&a)), 0, 0, 0, 0); errno != 0 {
+		return errno
+	}
+	return nil
+}

listener/redir/tcp_linux_other.go

@@ -0,0 +1,14 @@
+// +build linux,!386
+
+package redir
+
+import "syscall"
+
+const GETSOCKOPT = syscall.SYS_GETSOCKOPT
+
+func socketcall(call, a0, a1, a2, a3, a4, a5 uintptr) error {
+	if _, _, errno := syscall.Syscall6(call, a0, a1, a2, a3, a4, a5); errno != 0 {
+		return errno
+	}
+	return nil
+}

listener/redir/tcp_other.go

@@ -0,0 +1,14 @@
+// +build !darwin,!linux,!freebsd
+
+package redir
+
+import (
+	"errors"
+	"net"
+
+	"github.com/Dreamacro/clash/transport/socks5"
+)
+
+func parserPacket(conn net.Conn) (socks5.Addr, error) {
+	return nil, errors.New("system not support yet")
+}