mirror of
https://github.com/cwinfo/yggdrasil-go.git
synced 2024-11-12 23:20:28 +00:00
Remove ndp.go and add icmpv6.go
This commit is contained in:
Neil Alexander
parent
38567fffef
commit
be0d6feeba
203
src/yggdrasil/icmpv6.go
Normal file
203
src/yggdrasil/icmpv6.go
Normal file
@ -0,0 +1,203 @@
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package yggdrasil
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// The NDP functions are needed when you are running with a
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// TAP adapter - as the operating system expects neighbor solicitations
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// for on-link traffic, this goroutine provides them
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import "golang.org/x/net/icmp"
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import "encoding/binary"
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import "unsafe" // TODO investigate if this can be done without resorting to unsafe
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type macAddress [6]byte
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type ipv6Address [16]byte
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const ETHER = 14
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const IPV6 = 40
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type icmpv6 struct {
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tun *tunDevice
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peermac macAddress
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peerlladdr ipv6Address
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mymac macAddress
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mylladdr ipv6Address
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recv chan []byte
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}
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type etherHeader struct {
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destination macAddress
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source macAddress
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ethertype [2]byte
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}
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type ipv6Header struct {
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preamble [4]byte
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length [2]byte
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nextheader byte
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hoplimit byte
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source ipv6Address
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destination ipv6Address
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}
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type icmpv6Header struct {
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messagetype byte
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code byte
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checksum uint16
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}
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type icmpv6PseudoHeader struct {
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source ipv6Address
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destination ipv6Address
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length [4]byte
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zero [3]byte
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nextheader byte
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}
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type icmpv6Payload struct {
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ether etherHeader
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ipv6 ipv6Header
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icmpv6 icmpv6Header
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flags [4]byte
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targetaddress ipv6Address
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optiontype byte
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optionlength byte
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linklayeraddress macAddress
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}
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type icmpv6Packet struct {
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ipv6 ipv6Header
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payload icmpv6Payload
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}
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type icmpv6Frame struct {
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ether etherHeader
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packet icmpv6Packet
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}
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func (i *icmpv6) init(t *tunDevice) {
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i.tun = t
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i.recv = make(chan []byte)
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copy(i.mymac[:], []byte{0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
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copy(i.mylladdr[:], []byte{
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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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go i.listen()
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}
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func (i *icmpv6) listen() {
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for {
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datain := <-i.recv
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if i.tun.iface.IsTAP() {
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// TAP mode
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dataout := make([]byte, ETHER+IPV6+32)
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i.read_tap(datain, dataout)
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i.tun.iface.Write(dataout)
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} else {
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// TUN mode
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dataout := make([]byte, IPV6+32)
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i.read_tun(datain, dataout)
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i.tun.iface.Write(dataout)
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}
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}
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}
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func (i *icmpv6) read_tap(datain []byte, dataout []byte) {
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// Set up
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in := (*icmpv6Frame)(unsafe.Pointer(&datain[0]))
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out := (*icmpv6Frame)(unsafe.Pointer(&dataout[0]))
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// Store the peer MAC address
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copy(i.peermac[:6], in.ether.source[:6])
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// Ignore non-IPv6 frames
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if binary.BigEndian.Uint16(in.ether.ethertype[:]) != uint16(0x86DD) {
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return
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}
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// Populate the out ethernet headers
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copy(out.ether.destination[:], in.ether.destination[:])
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copy(out.ether.source[:], i.mymac[:])
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binary.BigEndian.PutUint16(out.ether.ethertype[:], uint16(0x86DD))
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// And for now just copy the rest of the packet we were sent
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copy(dataout[ETHER:ETHER+IPV6], datain[ETHER:ETHER+IPV6])
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// Then pass the IP packet onto the next function
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i.read_tun(datain[ETHER:], dataout[ETHER:])
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}
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func (i *icmpv6) read_tun(datain []byte, dataout []byte) {
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// Set up
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in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
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out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
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// Store the peer link-local address
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copy(i.peerlladdr[:16], in.ipv6.source[:16])
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// Ignore non-ICMPv6 packets
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if in.ipv6.nextheader != uint8(0x3A) {
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return
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}
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// What is the ICMPv6 message type?
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switch in.payload.icmpv6.messagetype {
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case uint8(135):
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i.handle_ndp(&in.payload, &out.payload)
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break
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}
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// Update the source and destination addresses in the IPv6 header
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copy(out.ipv6.destination[:], in.ipv6.source[:])
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copy(out.ipv6.source[:], i.mylladdr[:])
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binary.BigEndian.PutUint16(out.ipv6.length[:], uint16(32))
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// Copy the payload
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copy(dataout[IPV6:], datain[IPV6:])
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// Calculate the checksum
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i.calculate_checksum(dataout)
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}
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func (i *icmpv6) calculate_checksum(dataout []byte) {
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// Set up
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out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
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// Generate the pseudo-header for the checksum
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ps := make([]byte, 44)
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pseudo := (*icmpv6PseudoHeader)(unsafe.Pointer(&ps[0]))
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copy(pseudo.destination[:], out.ipv6.destination[:])
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copy(pseudo.source[:], out.ipv6.source[:])
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binary.BigEndian.PutUint32(pseudo.length[:], uint32(binary.BigEndian.Uint16(out.ipv6.length[:])))
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pseudo.nextheader = out.ipv6.nextheader
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// Lazy-man's checksum using the icmp library
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icmpv6, err := icmp.ParseMessage(0x3A, dataout[IPV6:])
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if err != nil {
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return
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}
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// And copy the payload
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payload, err := icmpv6.Marshal(ps)
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if err != nil {
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return
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}
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copy(dataout[IPV6:], payload)
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}
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func (i *icmpv6) handle_ndp(in *icmpv6Payload, out *icmpv6Payload) {
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// Ignore NDP requests for anything outside of fd00::/8
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if in.targetaddress[0] != 0xFD {
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return
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}
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// Update the ICMPv6 headers
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out.icmpv6.messagetype = uint8(136)
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out.icmpv6.code = uint8(0)
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// Update the ICMPv6 payload
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copy(out.targetaddress[:], in.targetaddress[:])
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out.optiontype = uint8(2)
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out.optionlength = uint8(1)
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copy(out.linklayeraddress[:], i.mymac[:])
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binary.BigEndian.PutUint32(out.flags[:], uint32(0x20000000))
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}
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@ -1,165 +0,0 @@
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package yggdrasil
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// The NDP functions are needed when you are running with a
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// TAP adapter - as the operating system expects neighbor solicitations
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// for on-link traffic, this goroutine provides them
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import "golang.org/x/net/icmp"
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import "encoding/binary"
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import "unsafe" // TODO investigate if this can be done without resorting to unsafe
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type macAddress [6]byte
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type ipv6Address [16]byte
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const ETHER = 14
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const IPV6 = 40
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type ndp struct {
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tun *tunDevice
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peermac macAddress
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peerlladdr ipv6Address
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mymac macAddress
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mylladdr ipv6Address
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recv chan []byte
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}
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type etherHeader struct {
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destination macAddress
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source macAddress
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ethertype [2]byte
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}
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type ipv6Header struct {
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preamble [4]byte
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length [2]byte
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nextheader byte
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hoplimit byte
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source ipv6Address
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destination ipv6Address
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}
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type icmpv6Header struct {
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messagetype byte
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code byte
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checksum uint16
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}
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type icmpv6PseudoHeader struct {
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source ipv6Address
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destination ipv6Address
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length [4]byte
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zero [3]byte
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nextheader byte
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}
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type icmpv6Packet struct {
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ether etherHeader
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ipv6 ipv6Header
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icmpv6 icmpv6Header
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flags [4]byte
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targetaddress ipv6Address
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optiontype byte
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optionlength byte
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linklayeraddress macAddress
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}
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func (n *ndp) init(t *tunDevice) {
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n.tun = t
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n.recv = make(chan []byte)
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copy(n.mymac[:], []byte{0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
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copy(n.mylladdr[:], []byte{
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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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go n.listen()
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}
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func (n *ndp) listen() {
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for {
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// Receive from the channel and check if we're using TAP instead
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// of TUN mode - NDP is only relevant for TAP
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datain := <-n.recv
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if !n.tun.iface.IsTAP() {
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continue
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}
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// Create our return frame buffer and also the unsafe pointers to
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// map them to the structs
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dataout := make([]byte, ETHER+IPV6+32)
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in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
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out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
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// Store peer MAC address and link-local IP address -
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// these will be used later by tun.go
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copy(n.peermac[:6], in.ether.source[:6])
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copy(n.peerlladdr[:16], in.ipv6.source[:16])
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// Ignore non-IPv6 packets
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if binary.BigEndian.Uint16(in.ether.ethertype[:]) != uint16(0x86DD) {
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continue
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}
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// Ignore non-ICMPv6 packets
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if in.ipv6.nextheader != uint8(0x3A) {
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continue
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}
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// Ignore non-NDP Solicitation packets
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if in.icmpv6.messagetype != uint8(135) {
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continue
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}
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// Ignore NDP requests for anything outside of fd00::/8
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if in.targetaddress[0] != 0xFD {
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continue
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}
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// Populate the out ethernet headers
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copy(out.ether.destination[:], in.ether.destination[:])
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copy(out.ether.source[:], n.mymac[:])
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binary.BigEndian.PutUint16(out.ether.ethertype[:], uint16(0x86DD))
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// And for now just copy the rest of the packet we were sent
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copy(dataout[ETHER:ETHER+IPV6], datain[ETHER:ETHER+IPV6])
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// Update the source and destination addresses in the IPv6 header
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copy(out.ipv6.destination[:], in.ipv6.source[:])
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copy(out.ipv6.source[:], n.mylladdr[:])
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binary.BigEndian.PutUint16(out.ipv6.length[:], uint16(32))
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// Copy the payload
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copy(dataout[ETHER+IPV6:], datain[ETHER+IPV6:])
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// Update the ICMPv6 headers
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out.icmpv6.messagetype = uint8(136)
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out.icmpv6.code = uint8(0)
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// Update the ICMPv6 payload
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copy(out.targetaddress[:], in.targetaddress[:])
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out.optiontype = uint8(2)
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out.optionlength = uint8(1)
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copy(out.linklayeraddress[:], n.mymac[:])
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binary.BigEndian.PutUint32(out.flags[:], uint32(0x20000000))
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// Generate the pseudo-header for the checksum
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ps := make([]byte, 44)
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pseudo := (*icmpv6PseudoHeader)(unsafe.Pointer(&ps[0]))
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copy(pseudo.destination[:], out.ipv6.destination[:])
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copy(pseudo.source[:], out.ipv6.source[:])
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binary.BigEndian.PutUint32(pseudo.length[:], uint32(binary.BigEndian.Uint16(out.ipv6.length[:])))
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pseudo.nextheader = out.ipv6.nextheader
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// Lazy-man's checksum using the icmp library
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icmpv6, err := icmp.ParseMessage(0x3A, dataout[ETHER+IPV6:])
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if err != nil {
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continue
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}
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payload, err := icmpv6.Marshal(ps)
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if err != nil {
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continue
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}
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copy(dataout[ETHER+IPV6:], payload)
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// Send the frame back to the TAP adapter
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n.tun.iface.Write(dataout)
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}
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}
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@ -17,17 +17,17 @@ type tunInterface interface {
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}
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type tunDevice struct {
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core *Core
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ndp ndp
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send chan<- []byte
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recv <-chan []byte
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mtu int
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iface tunInterface
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core *Core
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icmpv6 icmpv6
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send chan<- []byte
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recv <-chan []byte
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mtu int
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iface tunInterface
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}
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func (tun *tunDevice) init(core *Core) {
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tun.core = core
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tun.ndp.init(tun)
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tun.icmpv6.init(tun)
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}
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func (tun *tunDevice) write() error {
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@ -36,11 +36,11 @@ func (tun *tunDevice) write() error {
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if tun.iface.IsTAP() {
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var frame ethernet.Frame
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frame.Prepare(
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tun.ndp.peermac[:6], // Destination MAC address
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tun.ndp.mymac[:6], // Source MAC address
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ethernet.NotTagged, // VLAN tagging
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ethernet.IPv6, // Ethertype
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len(data)) // Payload length
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tun.icmpv6.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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len(data)) // Payload length
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copy(frame[ETHER_HEADER_LENGTH:], data[:])
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if _, err := tun.iface.Write(frame); err != nil {
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panic(err)
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@ -68,9 +68,6 @@ func (tun *tunDevice) read() error {
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o := 0
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if tun.iface.IsTAP() {
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o = ETHER_HEADER_LENGTH
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b := make([]byte, n)
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copy(b, buf)
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tun.ndp.recv <- b
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}
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if buf[o]&0xf0 != 0x60 ||
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n != 256*int(buf[o+4])+int(buf[o+5])+IPv6_HEADER_LENGTH+o {
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@ -78,6 +75,12 @@ func (tun *tunDevice) read() error {
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//panic("Should not happen in testing")
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continue
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}
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if buf[o+6] == 58 {
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// Found an ICMPv6 packet
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b := make([]byte, n)
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copy(b, buf)
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tun.icmpv6.recv <- b
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}
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packet := append(util_getBytes(), buf[o:n]...)
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tun.send <- packet
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}
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