mirror of
https://github.com/yggdrasil-network/yggdrasil-go.git
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Drop Water, use Wireguard tun library, drop TAP support
This commit is contained in:
Neil Alexander
parent
07ce8cde7a
commit
f5517acc81
20 changed files with 146 additions and 616 deletions
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@ -11,32 +11,16 @@ package tuntap
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import (
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"encoding/binary"
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"errors"
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"net"
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"sync"
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"time"
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"golang.org/x/net/icmp"
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"golang.org/x/net/ipv6"
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"github.com/yggdrasil-network/yggdrasil-go/src/address"
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)
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const len_ETHER = 14
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type ICMPv6 struct {
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tun *TunAdapter
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mylladdr net.IP
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mymac net.HardwareAddr
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peermacs map[address.Address]neighbor
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peermacsmutex sync.RWMutex
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}
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type neighbor struct {
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mac net.HardwareAddr
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learned bool
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lastadvertisement time.Time
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lastsolicitation time.Time
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tun *TunAdapter
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}
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// Marshal returns the binary encoding of h.
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@ -61,182 +45,6 @@ func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
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// addresses.
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func (i *ICMPv6) Init(t *TunAdapter) {
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i.tun = t
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i.peermacsmutex.Lock()
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i.peermacs = make(map[address.Address]neighbor)
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i.peermacsmutex.Unlock()
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// Our MAC address and link-local address
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i.mymac = net.HardwareAddr{
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0x02, 0x00, 0x00, 0x00, 0x00, 0x02}
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i.mylladdr = net.IP{
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0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xFE}
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copy(i.mymac[:], i.tun.addr[:])
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copy(i.mylladdr[9:], i.tun.addr[1:])
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}
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// Parses an incoming ICMPv6 packet. The packet provided may be either an
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// ethernet frame containing an IP packet, or the IP packet alone. This is
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// determined by whether the TUN/TAP adapter is running in TUN (layer 3) or
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// TAP (layer 2) mode. Returns an error condition which is nil if the ICMPv6
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// module handled the packet or contains the error if not.
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func (i *ICMPv6) ParsePacket(datain []byte) error {
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var response []byte
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var err error
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// Parse the frame/packet
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if i.tun.IsTAP() {
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response, err = i.UnmarshalPacketL2(datain)
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} else {
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response, err = i.UnmarshalPacket(datain, nil)
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}
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if err != nil {
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return err
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}
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// Write the packet to TUN/TAP
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i.tun.iface.Write(response)
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return nil
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}
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// Unwraps the ethernet headers of an incoming ICMPv6 packet and hands off
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// the IP packet to the ParsePacket function for further processing.
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// A response buffer is also created for the response message, also complete
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// with ethernet headers.
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func (i *ICMPv6) UnmarshalPacketL2(datain []byte) ([]byte, error) {
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// Ignore non-IPv6 frames
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if binary.BigEndian.Uint16(datain[12:14]) != uint16(0x86DD) {
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return nil, errors.New("Ignoring non-IPv6 frame")
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}
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// Hand over to ParsePacket to interpret the IPv6 packet
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mac := datain[6:12]
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ipv6packet, err := i.UnmarshalPacket(datain[len_ETHER:], &mac)
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if err != nil {
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return nil, err
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}
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// Create the response buffer
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dataout := make([]byte, len_ETHER+ipv6.HeaderLen+32)
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// Populate the response ethernet headers
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copy(dataout[:6], datain[6:12])
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copy(dataout[6:12], i.mymac[:])
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binary.BigEndian.PutUint16(dataout[12:14], uint16(0x86DD))
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// Copy the returned packet to our response ethernet frame
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copy(dataout[len_ETHER:], ipv6packet)
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return dataout, nil
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}
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// Unwraps the IP headers of an incoming IPv6 packet and performs various
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// sanity checks on the packet - i.e. is the packet an ICMPv6 packet, does the
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// ICMPv6 message match a known expected type. The relevant handler function
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// is then called and a response packet may be returned.
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func (i *ICMPv6) UnmarshalPacket(datain []byte, datamac *[]byte) ([]byte, error) {
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// Parse the IPv6 packet headers
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ipv6Header, err := ipv6.ParseHeader(datain[:ipv6.HeaderLen])
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if err != nil {
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return nil, err
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}
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// Check if the packet is IPv6
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if ipv6Header.Version != ipv6.Version {
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return nil, errors.New("Ignoring non-IPv6 packet")
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}
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// Check if the packet is ICMPv6
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if ipv6Header.NextHeader != 58 {
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return nil, errors.New("Ignoring non-ICMPv6 packet")
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}
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// Parse the ICMPv6 message contents
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icmpv6Header, err := icmp.ParseMessage(58, datain[ipv6.HeaderLen:])
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if err != nil {
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return nil, err
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}
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// Check for a supported message type
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switch icmpv6Header.Type {
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case ipv6.ICMPTypeNeighborSolicitation:
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if !i.tun.IsTAP() {
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return nil, errors.New("Ignoring Neighbor Solicitation in TUN mode")
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}
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response, err := i.HandleNDP(datain[ipv6.HeaderLen:])
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if err == nil {
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// Create our ICMPv6 response
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responsePacket, err := CreateICMPv6(
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ipv6Header.Src, i.mylladdr,
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ipv6.ICMPTypeNeighborAdvertisement, 0,
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&icmp.DefaultMessageBody{Data: response})
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if err != nil {
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return nil, err
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}
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// Send it back
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return responsePacket, nil
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} else {
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return nil, err
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}
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case ipv6.ICMPTypeNeighborAdvertisement:
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if !i.tun.IsTAP() {
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return nil, errors.New("Ignoring Neighbor Advertisement in TUN mode")
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}
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if datamac != nil {
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var addr address.Address
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var target address.Address
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mac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
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copy(addr[:], ipv6Header.Src[:])
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copy(target[:], datain[48:64])
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copy(mac[:], (*datamac)[:])
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i.peermacsmutex.Lock()
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neighbor := i.peermacs[target]
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neighbor.mac = mac
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neighbor.learned = true
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neighbor.lastadvertisement = time.Now()
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i.peermacs[target] = neighbor
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i.peermacsmutex.Unlock()
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i.tun.log.Debugln("Learned peer MAC", mac.String(), "for", net.IP(target[:]).String())
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/*
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i.tun.log.Debugln("Peer MAC table:")
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i.peermacsmutex.RLock()
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for t, n := range i.peermacs {
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if n.learned {
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i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "has MAC", n.mac.String())
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} else {
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i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "is not learned yet")
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}
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}
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i.peermacsmutex.RUnlock()
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*/
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}
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return nil, errors.New("No response needed")
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}
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return nil, errors.New("ICMPv6 type not matched")
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}
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// Creates an ICMPv6 packet based on the given icmp.MessageBody and other
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// parameters, complete with ethernet and IP headers, which can be written
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// directly to a TAP adapter.
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func (i *ICMPv6) CreateICMPv6L2(dstmac net.HardwareAddr, dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
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// Pass through to CreateICMPv6
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ipv6packet, err := CreateICMPv6(dst, src, mtype, mcode, mbody)
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if err != nil {
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return nil, err
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}
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// Create the response buffer
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dataout := make([]byte, len_ETHER+len(ipv6packet))
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// Populate the response ethernet headers
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copy(dataout[:6], dstmac[:6])
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copy(dataout[6:12], i.mymac[:])
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binary.BigEndian.PutUint16(dataout[12:14], uint16(0x86DD))
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// Copy the returned packet to our response ethernet frame
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copy(dataout[len_ETHER:], ipv6packet)
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return dataout, nil
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}
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// Creates an ICMPv6 packet based on the given icmp.MessageBody and other
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@ -281,106 +89,3 @@ func CreateICMPv6(dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody
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// Send it back
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return responsePacket, nil
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}
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func (i *ICMPv6) Solicit(addr address.Address) {
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retries := 5
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for retries > 0 {
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retries--
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i.peermacsmutex.RLock()
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if n, ok := i.peermacs[addr]; ok && n.learned {
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i.tun.log.Debugln("MAC learned for", net.IP(addr[:]).String())
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i.peermacsmutex.RUnlock()
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return
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}
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i.peermacsmutex.RUnlock()
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i.tun.log.Debugln("Sending neighbor solicitation for", net.IP(addr[:]).String())
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i.peermacsmutex.Lock()
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if n, ok := i.peermacs[addr]; !ok {
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i.peermacs[addr] = neighbor{
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lastsolicitation: time.Now(),
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}
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} else {
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n.lastsolicitation = time.Now()
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}
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i.peermacsmutex.Unlock()
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request, err := i.createNDPL2(addr)
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if err != nil {
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panic(err)
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}
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if _, err := i.tun.iface.Write(request); err != nil {
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panic(err)
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}
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i.tun.log.Debugln("Sent neighbor solicitation for", net.IP(addr[:]).String())
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time.Sleep(time.Second)
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}
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}
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func (i *ICMPv6) getNeighbor(addr address.Address) (neighbor, bool) {
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i.peermacsmutex.RLock()
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defer i.peermacsmutex.RUnlock()
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n, ok := i.peermacs[addr]
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return n, ok
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}
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func (i *ICMPv6) createNDPL2(dst address.Address) ([]byte, error) {
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// Create the ND payload
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var payload [28]byte
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copy(payload[:4], []byte{0x00, 0x00, 0x00, 0x00}) // Flags
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copy(payload[4:20], dst[:]) // Destination
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copy(payload[20:22], []byte{0x01, 0x01}) // Type & length
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copy(payload[22:28], i.mymac[:6]) // Link layer address
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// Create the ICMPv6 solicited-node address
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var dstaddr address.Address
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copy(dstaddr[:13], []byte{
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0xFF, 0x02, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x01, 0xFF})
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copy(dstaddr[13:], dst[13:16])
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// Create the multicast MAC
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dstmac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
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copy(dstmac[:2], []byte{0x33, 0x33})
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copy(dstmac[2:6], dstaddr[12:16])
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// Create the ND request
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requestPacket, err := i.CreateICMPv6L2(
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dstmac, dstaddr[:], i.mylladdr,
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ipv6.ICMPTypeNeighborSolicitation, 0,
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&icmp.DefaultMessageBody{Data: payload[:]})
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if err != nil {
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return nil, err
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}
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return requestPacket, nil
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}
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// Generates a response to an NDP discovery packet. This is effectively called
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// when the host operating system generates an NDP request for any address in
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// the fd00::/8 range, so that the operating system knows to route that traffic
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// to the Yggdrasil TAP adapter.
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func (i *ICMPv6) HandleNDP(in []byte) ([]byte, error) {
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// Ignore NDP requests for anything outside of fd00::/8
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var source address.Address
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copy(source[:], in[8:])
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var snet address.Subnet
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copy(snet[:], in[8:])
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switch {
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case source.IsValid():
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case snet.IsValid():
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default:
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return nil, errors.New("Not an NDP for 0200::/7")
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}
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// Create our NDP message body response
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body := make([]byte, 28)
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binary.BigEndian.PutUint32(body[:4], uint32(0x40000000)) // Flags
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copy(body[4:20], in[8:24]) // Target address
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body[20] = uint8(2) // Type: Target link-layer address
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body[21] = uint8(1) // Length: 1x address (8 bytes)
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copy(body[22:28], i.mymac[:6])
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// Send it back
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return body, nil
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}
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