mirror of
https://github.com/cwinfo/yggdrasil-go.git
synced 2024-11-25 23:01:38 +00:00
More complete NDP implementation for TAP mode, which tracks individual MAC addresses for neighbors
This commit is contained in:
Neil Alexander
parent
7af85c7d70
commit
d50e1bc803
@ -24,10 +24,9 @@ const len_ETHER = 14
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type icmpv6 struct {
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tun *tunDevice
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peermac macAddress
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peerlladdr net.IP
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mylladdr net.IP
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mymac macAddress
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peermacs map[address]macAddress
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}
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// Marshal returns the binary encoding of h.
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@ -52,13 +51,16 @@ func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
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// addresses.
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func (i *icmpv6) init(t *tunDevice) {
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i.tun = t
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i.peermacs = make(map[address]macAddress)
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// Our MAC address and link-local address
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copy(i.mymac[:], []byte{
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0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
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i.mymac = macAddress{
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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[1:], i.tun.core.boxPub[:])
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copy(i.mylladdr[9:], i.tun.core.boxPub[:])
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}
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// Parses an incoming ICMPv6 packet. The packet provided may be either an
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@ -73,7 +75,7 @@ func (i *icmpv6) parse_packet(datain []byte) {
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if i.tun.iface.IsTAP() {
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response, err = i.parse_packet_tap(datain)
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} else {
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response, err = i.parse_packet_tun(datain)
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response, err = i.parse_packet_tun(datain, nil)
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}
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if err != nil {
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@ -89,16 +91,14 @@ func (i *icmpv6) parse_packet(datain []byte) {
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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) parse_packet_tap(datain []byte) ([]byte, error) {
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// Store the peer MAC address
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copy(i.peermac[:6], datain[6:12])
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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, nil
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}
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// Hand over to parse_packet_tun to interpret the IPv6 packet
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ipv6packet, err := i.parse_packet_tun(datain[len_ETHER:])
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mac := datain[6:12]
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ipv6packet, err := i.parse_packet_tun(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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@ -120,7 +120,7 @@ func (i *icmpv6) parse_packet_tap(datain []byte) ([]byte, error) {
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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) parse_packet_tun(datain []byte) ([]byte, error) {
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func (i *icmpv6) parse_packet_tun(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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@ -137,9 +137,6 @@ func (i *icmpv6) parse_packet_tun(datain []byte) ([]byte, error) {
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return nil, err
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}
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// Store the peer link local address, it will come in useful later
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copy(i.peerlladdr[:], ipv6Header.Src[:])
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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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@ -149,7 +146,6 @@ func (i *icmpv6) parse_packet_tun(datain []byte) ([]byte, error) {
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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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{
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response, err := i.handle_ndp(datain[ipv6.HeaderLen:])
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if err == nil {
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// Create our ICMPv6 response
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@ -166,7 +162,15 @@ func (i *icmpv6) parse_packet_tun(datain []byte) ([]byte, error) {
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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 datamac != nil {
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var addr address
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var mac macAddress
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copy(addr[:], ipv6Header.Src[:])
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copy(mac[:], (*datamac)[:])
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i.peermacs[addr] = mac
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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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@ -238,6 +242,55 @@ func (i *icmpv6) create_icmpv6_tun(dst net.IP, src net.IP, mtype ipv6.ICMPType,
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return responsePacket, nil
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}
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func (i *icmpv6) create_ndp_tap(in []byte) ([]byte, error) {
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// Parse the IPv6 packet headers
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ipv6Header, err := ipv6.ParseHeader(in[: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, err
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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, err
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}
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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})
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copy(payload[4:20], ipv6Header.Dst[:])
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copy(payload[20:22], []byte{0x01, 0x01})
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copy(payload[22:28], i.mymac[:6])
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// Create the ICMPv6 solicited-node address
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var dstaddr 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:], ipv6Header.Dst[13:16])
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// Create the multicast MAC
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var dstmac macAddress
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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.create_icmpv6_tap(
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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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@ -3,6 +3,7 @@ package yggdrasil
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// This manages the tun driver to send/recv packets to/from applications
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import (
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"errors"
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"yggdrasil/defaults"
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"github.com/songgao/packets/ethernet"
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@ -61,9 +62,24 @@ func (tun *tunDevice) write() error {
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continue
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}
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if tun.iface.IsTAP() {
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var destAddr address
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if data[0]&0xf0 == 0x60 {
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if len(data) < 40 {
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panic("Tried to send a packet shorter than an IPv6 header...")
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}
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copy(destAddr[:16], data[24:])
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} else if data[0]&0xf0 == 0x40 {
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if len(data) < 20 {
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panic("Tried to send a packet shorter than an IPv4 header...")
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}
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copy(destAddr[:4], data[16:])
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} else {
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return errors.New("Invalid address family")
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}
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if peermac, ok := tun.icmpv6.peermacs[destAddr]; ok {
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var frame ethernet.Frame
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frame.Prepare(
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tun.icmpv6.peermac[:6], // Destination MAC address
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peermac[:6], // Destination MAC address
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tun.icmpv6.mymac[:6], // Source MAC address
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ethernet.NotTagged, // VLAN tagging
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ethernet.IPv6, // Ethertype
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@ -72,6 +88,16 @@ func (tun *tunDevice) write() error {
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if _, err := tun.iface.Write(frame); err != nil {
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panic(err)
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}
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} else {
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request, err := tun.icmpv6.create_ndp_tap(data)
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if err != nil {
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panic(err)
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}
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if _, err := tun.iface.Write(request); err != nil {
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panic(err)
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}
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}
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} else {
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if _, err := tun.iface.Write(data); err != nil {
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panic(err)
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