mirror of
https://github.com/cwinfo/yggdrasil-go.git
synced 2024-11-13 00:30:28 +00:00
move some logic from TunAdapter.reader into a new function, TunAdapter.readerPacketHandler
This commit is contained in:
Arceliar
parent
38e1503b28
commit
406e143f7f
@ -110,178 +110,10 @@ func (tun *TunAdapter) writer() error {
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}
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}
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func (tun *TunAdapter) reader() error {
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recvd := make([]byte, 65535+tun_ETHER_HEADER_LENGTH)
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toWorker := make(chan []byte, 32)
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defer close(toWorker)
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go func() {
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for bs := range toWorker {
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// If we detect an ICMP packet then hand it to the ICMPv6 module
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if bs[6] == 58 {
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// Found an ICMPv6 packet - we need to make sure to give ICMPv6 the full
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// Ethernet frame rather than just the IPv6 packet as this is needed for
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// NDP to work correctly
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if err := tun.icmpv6.ParsePacket(recvd); err == nil {
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// We acted on the packet in the ICMPv6 module so don't forward or do
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// anything else with it
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continue
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}
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}
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// From the IP header, work out what our source and destination addresses
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// and node IDs are. We will need these in order to work out where to send
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// the packet
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var srcAddr address.Address
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var dstAddr address.Address
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var dstNodeID *crypto.NodeID
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var dstNodeIDMask *crypto.NodeID
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var dstSnet address.Subnet
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var addrlen int
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n := len(bs)
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// Check the IP protocol - if it doesn't match then we drop the packet and
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// do nothing with it
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if bs[0]&0xf0 == 0x60 {
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// Check if we have a fully-sized IPv6 header
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if len(bs) < 40 {
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continue
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}
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// Check the packet size
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if n-tun_IPv6_HEADER_LENGTH != 256*int(bs[4])+int(bs[5]) {
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continue
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}
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// IPv6 address
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addrlen = 16
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copy(srcAddr[:addrlen], bs[8:])
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copy(dstAddr[:addrlen], bs[24:])
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copy(dstSnet[:addrlen/2], bs[24:])
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} else if bs[0]&0xf0 == 0x40 {
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// Check if we have a fully-sized IPv4 header
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if len(bs) < 20 {
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continue
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}
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// Check the packet size
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if n != 256*int(bs[2])+int(bs[3]) {
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continue
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}
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// IPv4 address
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addrlen = 4
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copy(srcAddr[:addrlen], bs[12:])
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copy(dstAddr[:addrlen], bs[16:])
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} else {
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// Unknown address length or protocol, so drop the packet and ignore it
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tun.log.Traceln("Unknown packet type, dropping")
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continue
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}
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if tun.ckr.isEnabled() && !tun.ckr.isValidSource(srcAddr, addrlen) {
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// The packet had a source address that doesn't belong to us or our
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// configured crypto-key routing source subnets
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continue
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}
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if !dstAddr.IsValid() && !dstSnet.IsValid() {
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if key, err := tun.ckr.getPublicKeyForAddress(dstAddr, addrlen); err == nil {
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// A public key was found, get the node ID for the search
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dstNodeID = crypto.GetNodeID(&key)
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// Do a quick check to ensure that the node ID refers to a vaild
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// Yggdrasil address or subnet - this might be superfluous
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addr := *address.AddrForNodeID(dstNodeID)
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copy(dstAddr[:], addr[:])
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copy(dstSnet[:], addr[:])
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// Are we certain we looked up a valid node?
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if !dstAddr.IsValid() && !dstSnet.IsValid() {
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continue
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}
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} else {
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// No public key was found in the CKR table so we've exhausted our options
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continue
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}
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}
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// Do we have an active connection for this node address?
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tun.mutex.RLock()
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session, isIn := tun.addrToConn[dstAddr]
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if !isIn || session == nil {
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session, isIn = tun.subnetToConn[dstSnet]
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if !isIn || session == nil {
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// Neither an address nor a subnet mapping matched, therefore populate
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// the node ID and mask to commence a search
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if dstAddr.IsValid() {
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dstNodeID, dstNodeIDMask = dstAddr.GetNodeIDandMask()
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} else {
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dstNodeID, dstNodeIDMask = dstSnet.GetNodeIDandMask()
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}
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}
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}
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tun.mutex.RUnlock()
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// If we don't have a connection then we should open one
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if !isIn || session == nil {
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// Check we haven't been given empty node ID, really this shouldn't ever
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// happen but just to be sure...
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if dstNodeID == nil || dstNodeIDMask == nil {
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panic("Given empty dstNodeID and dstNodeIDMask - this shouldn't happen")
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}
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// Dial to the remote node
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packet := bs
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go func() {
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// FIXME just spitting out a goroutine to do this is kind of ugly and means we drop packets until the dial finishes
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tun.mutex.Lock()
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_, known := tun.dials[*dstNodeID]
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tun.dials[*dstNodeID] = append(tun.dials[*dstNodeID], packet)
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for len(tun.dials[*dstNodeID]) > 32 {
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util.PutBytes(tun.dials[*dstNodeID][0])
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tun.dials[*dstNodeID] = tun.dials[*dstNodeID][1:]
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}
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tun.mutex.Unlock()
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if known {
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return
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}
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var tc *tunConn
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if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
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// We've been given a connection so prepare the session wrapper
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if tc, err = tun.wrap(conn); err != nil {
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// Something went wrong when storing the connection, typically that
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// something already exists for this address or subnet
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tun.log.Debugln("TUN/TAP iface wrap:", err)
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}
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}
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tun.mutex.Lock()
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packets := tun.dials[*dstNodeID]
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delete(tun.dials, *dstNodeID)
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tun.mutex.Unlock()
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if tc != nil {
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for _, packet := range packets {
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select {
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case tc.send <- packet:
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default:
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util.PutBytes(packet)
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}
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}
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}
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}()
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// While the dial is going on we can't do much else
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// continuing this iteration - skip to the next one
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continue
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}
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// If we have a connection now, try writing to it
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if isIn && session != nil {
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packet := bs
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select {
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case session.send <- packet:
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default:
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util.PutBytes(packet)
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}
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}
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}
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}()
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for {
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// Wait for a packet to be delivered to us through the TUN/TAP adapter
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n, err := tun.iface.Read(recvd)
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if err != nil {
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if !tun.isOpen {
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return err
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}
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panic(err)
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}
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if n == 0 {
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continue
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}
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// Run in a separate goroutine by the reader
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// Does all of the per-packet ICMP checks, passes packets to the right Conn worker
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func (tun *TunAdapter) readerPacketHandler(ch chan []byte) {
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for recvd := range ch {
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// If it's a TAP adapter, update the buffer slice so that we no longer
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// include the ethernet headers
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offset := 0
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@ -295,7 +127,180 @@ func (tun *TunAdapter) reader() error {
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}
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// Offset the buffer from now on so that we can ignore ethernet frames if
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// they are present
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bs := append(util.GetBytes(), recvd[offset:offset+n]...)
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bs := recvd[offset:]
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// If we detect an ICMP packet then hand it to the ICMPv6 module
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if bs[6] == 58 {
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// Found an ICMPv6 packet - we need to make sure to give ICMPv6 the full
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// Ethernet frame rather than just the IPv6 packet as this is needed for
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// NDP to work correctly
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if err := tun.icmpv6.ParsePacket(recvd); err == nil {
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// We acted on the packet in the ICMPv6 module so don't forward or do
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// anything else with it
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continue
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}
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}
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// Shift forward to avoid leaking bytes off the front of the slide when we eventually store it
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bs = append(recvd[:0], bs...)
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// From the IP header, work out what our source and destination addresses
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// and node IDs are. We will need these in order to work out where to send
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// the packet
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var srcAddr address.Address
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var dstAddr address.Address
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var dstNodeID *crypto.NodeID
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var dstNodeIDMask *crypto.NodeID
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var dstSnet address.Subnet
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var addrlen int
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n := len(bs)
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// Check the IP protocol - if it doesn't match then we drop the packet and
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// do nothing with it
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if bs[0]&0xf0 == 0x60 {
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// Check if we have a fully-sized IPv6 header
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if len(bs) < 40 {
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continue
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}
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// Check the packet size
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if n-tun_IPv6_HEADER_LENGTH != 256*int(bs[4])+int(bs[5]) {
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continue
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}
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// IPv6 address
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addrlen = 16
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copy(srcAddr[:addrlen], bs[8:])
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copy(dstAddr[:addrlen], bs[24:])
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copy(dstSnet[:addrlen/2], bs[24:])
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} else if bs[0]&0xf0 == 0x40 {
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// Check if we have a fully-sized IPv4 header
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if len(bs) < 20 {
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continue
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}
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// Check the packet size
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if n != 256*int(bs[2])+int(bs[3]) {
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continue
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}
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// IPv4 address
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addrlen = 4
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copy(srcAddr[:addrlen], bs[12:])
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copy(dstAddr[:addrlen], bs[16:])
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} else {
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// Unknown address length or protocol, so drop the packet and ignore it
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tun.log.Traceln("Unknown packet type, dropping")
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continue
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}
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if tun.ckr.isEnabled() && !tun.ckr.isValidSource(srcAddr, addrlen) {
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// The packet had a source address that doesn't belong to us or our
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// configured crypto-key routing source subnets
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continue
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}
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if !dstAddr.IsValid() && !dstSnet.IsValid() {
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if key, err := tun.ckr.getPublicKeyForAddress(dstAddr, addrlen); err == nil {
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// A public key was found, get the node ID for the search
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dstNodeID = crypto.GetNodeID(&key)
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// Do a quick check to ensure that the node ID refers to a vaild
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// Yggdrasil address or subnet - this might be superfluous
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addr := *address.AddrForNodeID(dstNodeID)
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copy(dstAddr[:], addr[:])
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copy(dstSnet[:], addr[:])
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// Are we certain we looked up a valid node?
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if !dstAddr.IsValid() && !dstSnet.IsValid() {
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continue
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}
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} else {
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// No public key was found in the CKR table so we've exhausted our options
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continue
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}
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}
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// Do we have an active connection for this node address?
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tun.mutex.RLock()
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session, isIn := tun.addrToConn[dstAddr]
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if !isIn || session == nil {
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session, isIn = tun.subnetToConn[dstSnet]
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if !isIn || session == nil {
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// Neither an address nor a subnet mapping matched, therefore populate
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// the node ID and mask to commence a search
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if dstAddr.IsValid() {
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dstNodeID, dstNodeIDMask = dstAddr.GetNodeIDandMask()
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} else {
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dstNodeID, dstNodeIDMask = dstSnet.GetNodeIDandMask()
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}
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}
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}
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tun.mutex.RUnlock()
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// If we don't have a connection then we should open one
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if !isIn || session == nil {
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// Check we haven't been given empty node ID, really this shouldn't ever
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// happen but just to be sure...
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if dstNodeID == nil || dstNodeIDMask == nil {
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panic("Given empty dstNodeID and dstNodeIDMask - this shouldn't happen")
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}
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// Dial to the remote node
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go func() {
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// FIXME just spitting out a goroutine to do this is kind of ugly and means we drop packets until the dial finishes
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tun.mutex.Lock()
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_, known := tun.dials[*dstNodeID]
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tun.dials[*dstNodeID] = append(tun.dials[*dstNodeID], bs)
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for len(tun.dials[*dstNodeID]) > 32 {
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util.PutBytes(tun.dials[*dstNodeID][0])
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tun.dials[*dstNodeID] = tun.dials[*dstNodeID][1:]
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}
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tun.mutex.Unlock()
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if known {
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return
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}
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var tc *tunConn
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if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
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// We've been given a connection so prepare the session wrapper
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if tc, err = tun.wrap(conn); err != nil {
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// Something went wrong when storing the connection, typically that
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// something already exists for this address or subnet
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tun.log.Debugln("TUN/TAP iface wrap:", err)
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}
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}
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tun.mutex.Lock()
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packets := tun.dials[*dstNodeID]
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delete(tun.dials, *dstNodeID)
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tun.mutex.Unlock()
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if tc != nil {
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for _, packet := range packets {
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select {
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case tc.send <- packet:
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default:
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util.PutBytes(packet)
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}
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}
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}
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}()
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// While the dial is going on we can't do much else
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// continuing this iteration - skip to the next one
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continue
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}
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// If we have a connection now, try writing to it
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if isIn && session != nil {
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select {
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case session.send <- bs:
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default:
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util.PutBytes(bs)
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}
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}
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}
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}
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func (tun *TunAdapter) reader() error {
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recvd := make([]byte, 65535+tun_ETHER_HEADER_LENGTH)
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toWorker := make(chan []byte, 32)
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defer close(toWorker)
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go tun.readerPacketHandler(toWorker)
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for {
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// Wait for a packet to be delivered to us through the TUN/TAP adapter
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n, err := tun.iface.Read(recvd)
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if err != nil {
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if !tun.isOpen {
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return err
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}
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panic(err)
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}
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if n == 0 {
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continue
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}
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bs := append(util.GetBytes(), recvd[:n]...)
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toWorker <- bs
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}
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}
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