github.com/liloew/wireguard-go@v0.0.0-20220224014633-9cd745e6f114/conn/conn.go (about)

     1  /* SPDX-License-Identifier: MIT
     2   *
     3   * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
     4   */
     5  
     6  // Package conn implements WireGuard's network connections.
     7  package conn
     8  
     9  import (
    10  	"errors"
    11  	"fmt"
    12  	"reflect"
    13  	"runtime"
    14  	"strings"
    15  
    16  	"golang.zx2c4.com/go118/netip"
    17  )
    18  
    19  // A ReceiveFunc receives a single inbound packet from the network.
    20  // It writes the data into b. n is the length of the packet.
    21  // ep is the remote endpoint.
    22  type ReceiveFunc func(b []byte) (n int, ep Endpoint, err error)
    23  
    24  // A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
    25  //
    26  // A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
    27  // depending on the platform-specific implementation.
    28  type Bind interface {
    29  	// Open puts the Bind into a listening state on a given port and reports the actual
    30  	// port that it bound to. Passing zero results in a random selection.
    31  	// fns is the set of functions that will be called to receive packets.
    32  	Open(port uint16) (fns []ReceiveFunc, actualPort uint16, err error)
    33  
    34  	// Close closes the Bind listener.
    35  	// All fns returned by Open must return net.ErrClosed after a call to Close.
    36  	Close() error
    37  
    38  	// SetMark sets the mark for each packet sent through this Bind.
    39  	// This mark is passed to the kernel as the socket option SO_MARK.
    40  	SetMark(mark uint32) error
    41  
    42  	// Send writes a packet b to address ep.
    43  	Send(b []byte, ep Endpoint) error
    44  
    45  	// ParseEndpoint creates a new endpoint from a string.
    46  	ParseEndpoint(s string) (Endpoint, error)
    47  }
    48  
    49  // BindSocketToInterface is implemented by Bind objects that support being
    50  // tied to a single network interface. Used by wireguard-windows.
    51  type BindSocketToInterface interface {
    52  	BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
    53  	BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
    54  }
    55  
    56  // PeekLookAtSocketFd is implemented by Bind objects that support having their
    57  // file descriptor peeked at. Used by wireguard-android.
    58  type PeekLookAtSocketFd interface {
    59  	PeekLookAtSocketFd4() (fd int, err error)
    60  	PeekLookAtSocketFd6() (fd int, err error)
    61  }
    62  
    63  // An Endpoint maintains the source/destination caching for a peer.
    64  //
    65  //	dst: the remote address of a peer ("endpoint" in uapi terminology)
    66  //	src: the local address from which datagrams originate going to the peer
    67  type Endpoint interface {
    68  	ClearSrc()           // clears the source address
    69  	SrcToString() string // returns the local source address (ip:port)
    70  	DstToString() string // returns the destination address (ip:port)
    71  	DstToBytes() []byte  // used for mac2 cookie calculations
    72  	DstIP() netip.Addr
    73  	SrcIP() netip.Addr
    74  }
    75  
    76  var (
    77  	ErrBindAlreadyOpen   = errors.New("bind is already open")
    78  	ErrWrongEndpointType = errors.New("endpoint type does not correspond with bind type")
    79  )
    80  
    81  func (fn ReceiveFunc) PrettyName() string {
    82  	name := runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()
    83  	// 0. cheese/taco.beansIPv6.func12.func21218-fm
    84  	name = strings.TrimSuffix(name, "-fm")
    85  	// 1. cheese/taco.beansIPv6.func12.func21218
    86  	if idx := strings.LastIndexByte(name, '/'); idx != -1 {
    87  		name = name[idx+1:]
    88  		// 2. taco.beansIPv6.func12.func21218
    89  	}
    90  	for {
    91  		var idx int
    92  		for idx = len(name) - 1; idx >= 0; idx-- {
    93  			if name[idx] < '0' || name[idx] > '9' {
    94  				break
    95  			}
    96  		}
    97  		if idx == len(name)-1 {
    98  			break
    99  		}
   100  		const dotFunc = ".func"
   101  		if !strings.HasSuffix(name[:idx+1], dotFunc) {
   102  			break
   103  		}
   104  		name = name[:idx+1-len(dotFunc)]
   105  		// 3. taco.beansIPv6.func12
   106  		// 4. taco.beansIPv6
   107  	}
   108  	if idx := strings.LastIndexByte(name, '.'); idx != -1 {
   109  		name = name[idx+1:]
   110  		// 5. beansIPv6
   111  	}
   112  	if name == "" {
   113  		return fmt.Sprintf("%p", fn)
   114  	}
   115  	if strings.HasSuffix(name, "IPv4") {
   116  		return "v4"
   117  	}
   118  	if strings.HasSuffix(name, "IPv6") {
   119  		return "v6"
   120  	}
   121  	return name
   122  }