EtherGuard-VPN/conn/conn.go
Josh Bleecher Snyder 10533c3e73 all: make conn.Bind.Open return a slice of receive functions
Instead of hard-coding exactly two sources from which
to receive packets (an IPv4 source and an IPv6 source),
allow the conn.Bind to specify a set of sources.

Beneficial consequences:

* If there's no IPv6 support on a system,
  conn.Bind.Open can choose not to return a receive function for it,
  which is simpler than tracking that state in the bind.
  This simplification removes existing data races from both
  conn.StdNetBind and bindtest.ChannelBind.
* If there are more than two sources on a system,
  the conn.Bind no longer needs to add a separate muxing layer.

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
2021-04-02 11:07:08 -06:00

106 lines
3.4 KiB
Go

/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
*/
// Package conn implements WireGuard's network connections.
package conn
import (
"errors"
"net"
"strings"
)
// A ReceiveFunc receives a single inbound packet from the network.
// It writes the data into b. n is the length of the packet.
// ep is the remote endpoint.
type ReceiveFunc func(b []byte) (n int, ep Endpoint, err error)
// A Bind listens on a port for both IPv6 and IPv4 UDP traffic.
//
// A Bind interface may also be a PeekLookAtSocketFd or BindSocketToInterface,
// depending on the platform-specific implementation.
type Bind interface {
// Open puts the Bind into a listening state on a given port and reports the actual
// port that it bound to. Passing zero results in a random selection.
// fns is the set of functions that will be called to receive packets.
Open(port uint16) (fns []ReceiveFunc, actualPort uint16, err error)
// Close closes the Bind listener.
// All fns returned by Open must return net.ErrClosed after a call to Close.
Close() error
// SetMark sets the mark for each packet sent through this Bind.
// This mark is passed to the kernel as the socket option SO_MARK.
SetMark(mark uint32) error
// Send writes a packet b to address ep.
Send(b []byte, ep Endpoint) error
// ParseEndpoint creates a new endpoint from a string.
ParseEndpoint(s string) (Endpoint, error)
}
// BindSocketToInterface is implemented by Bind objects that support being
// tied to a single network interface. Used by wireguard-windows.
type BindSocketToInterface interface {
BindSocketToInterface4(interfaceIndex uint32, blackhole bool) error
BindSocketToInterface6(interfaceIndex uint32, blackhole bool) error
}
// PeekLookAtSocketFd is implemented by Bind objects that support having their
// file descriptor peeked at. Used by wireguard-android.
type PeekLookAtSocketFd interface {
PeekLookAtSocketFd4() (fd int, err error)
PeekLookAtSocketFd6() (fd int, err error)
}
// An Endpoint maintains the source/destination caching for a peer.
//
// dst: the remote address of a peer ("endpoint" in uapi terminology)
// src: the local address from which datagrams originate going to the peer
type Endpoint interface {
ClearSrc() // clears the source address
SrcToString() string // returns the local source address (ip:port)
DstToString() string // returns the destination address (ip:port)
DstToBytes() []byte // used for mac2 cookie calculations
DstIP() net.IP
SrcIP() net.IP
}
func parseEndpoint(s string) (*net.UDPAddr, error) {
// ensure that the host is an IP address
host, _, err := net.SplitHostPort(s)
if err != nil {
return nil, err
}
if i := strings.LastIndexByte(host, '%'); i > 0 && strings.IndexByte(host, ':') >= 0 {
// Remove the scope, if any. ResolveUDPAddr below will use it, but here we're just
// trying to make sure with a small sanity test that this is a real IP address and
// not something that's likely to incur DNS lookups.
host = host[:i]
}
if ip := net.ParseIP(host); ip == nil {
return nil, errors.New("Failed to parse IP address: " + host)
}
// parse address and port
addr, err := net.ResolveUDPAddr("udp", s)
if err != nil {
return nil, err
}
ip4 := addr.IP.To4()
if ip4 != nil {
addr.IP = ip4
}
return addr, err
}
var (
ErrBindAlreadyOpen = errors.New("bind is already open")
ErrWrongEndpointType = errors.New("endpoint type does not correspond with bind type")
)