Add new reject channel to router so we can send back rejected packets to adapter (e.g. for ICMPv6 Packet Too Big), implement ICMPv6 PTB in TUN/TAP instead of router

This commit is contained in:
Neil Alexander 2019-03-28 09:50:13 +00:00
parent 0715e829c2
commit eb22ed44ac
No known key found for this signature in database
GPG key ID: A02A2019A2BB0944
3 changed files with 135 additions and 96 deletions

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@ -11,6 +11,8 @@ import (
"time"
"github.com/gologme/log"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv6"
"github.com/songgao/packets/ethernet"
"github.com/yggdrasil-network/water"
@ -64,10 +66,10 @@ func (tun *TunAdapter) IsTAP() bool {
}
// Initialises the TUN/TAP adapter.
func (tun *TunAdapter) Init(config *config.NodeState, log *log.Logger, send chan<- []byte, recv <-chan []byte) {
func (tun *TunAdapter) Init(config *config.NodeState, log *log.Logger, send chan<- []byte, recv <-chan []byte, reject <-chan yggdrasil.RejectedPacket) {
tun.config = config
tun.log = log
tun.Adapter.Init(config, log, send, recv)
tun.Adapter.Init(config, log, send, recv, reject)
tun.icmpv6.Init(tun)
go func() {
for {
@ -146,81 +148,118 @@ func (tun *TunAdapter) Start(a address.Address, s address.Subnet) error {
// host operating system.
func (tun *TunAdapter) Write() error {
for {
data := <-tun.Recv
if tun.iface == nil {
continue
}
if tun.iface.IsTAP() {
var destAddr address.Address
if data[0]&0xf0 == 0x60 {
if len(data) < 40 {
//panic("Tried to send a packet shorter than an IPv6 header...")
util.PutBytes(data)
continue
select {
case reject := <-tun.Reject:
switch reject.Reason {
case yggdrasil.PacketTooBig:
if mtu, ok := reject.Detail.(int); ok {
// Create the Packet Too Big response
ptb := &icmp.PacketTooBig{
MTU: int(mtu),
Data: reject.Packet,
}
// Create the ICMPv6 response from it
icmpv6Buf, err := CreateICMPv6(
reject.Packet[8:24], reject.Packet[24:40],
ipv6.ICMPTypePacketTooBig, 0, ptb)
// Send the ICMPv6 response back to the TUN/TAP adapter
if err == nil {
tun.iface.Write(icmpv6Buf)
}
}
copy(destAddr[:16], data[24:])
} else if data[0]&0xf0 == 0x40 {
if len(data) < 20 {
//panic("Tried to send a packet shorter than an IPv4 header...")
util.PutBytes(data)
continue
}
copy(destAddr[:4], data[16:])
} else {
return errors.New("Invalid address family")
fallthrough
default:
continue
}
sendndp := func(destAddr address.Address) {
neigh, known := tun.icmpv6.peermacs[destAddr]
known = known && (time.Since(neigh.lastsolicitation).Seconds() < 30)
if !known {
request, err := tun.icmpv6.CreateNDPL2(destAddr)
if err != nil {
panic(err)
case data := <-tun.Recv:
if tun.iface == nil {
continue
}
if tun.iface.IsTAP() {
var destAddr address.Address
if data[0]&0xf0 == 0x60 {
if len(data) < 40 {
//panic("Tried to send a packet shorter than an IPv6 header...")
util.PutBytes(data)
continue
}
if _, err := tun.iface.Write(request); err != nil {
panic(err)
copy(destAddr[:16], data[24:])
} else if data[0]&0xf0 == 0x40 {
if len(data) < 20 {
//panic("Tried to send a packet shorter than an IPv4 header...")
util.PutBytes(data)
continue
}
tun.icmpv6.peermacs[destAddr] = neighbor{
lastsolicitation: time.Now(),
copy(destAddr[:4], data[16:])
} else {
return errors.New("Invalid address family")
}
sendndp := func(destAddr address.Address) {
neigh, known := tun.icmpv6.peermacs[destAddr]
known = known && (time.Since(neigh.lastsolicitation).Seconds() < 30)
if !known {
request, err := tun.icmpv6.CreateNDPL2(destAddr)
if err != nil {
panic(err)
}
if _, err := tun.iface.Write(request); err != nil {
panic(err)
}
tun.icmpv6.peermacs[destAddr] = neighbor{
lastsolicitation: time.Now(),
}
}
}
}
var peermac macAddress
var peerknown bool
if data[0]&0xf0 == 0x40 {
destAddr = tun.addr
} else if data[0]&0xf0 == 0x60 {
if !bytes.Equal(tun.addr[:16], destAddr[:16]) && !bytes.Equal(tun.subnet[:8], destAddr[:8]) {
var peermac macAddress
var peerknown bool
if data[0]&0xf0 == 0x40 {
destAddr = tun.addr
} else if data[0]&0xf0 == 0x60 {
if !bytes.Equal(tun.addr[:16], destAddr[:16]) && !bytes.Equal(tun.subnet[:8], destAddr[:8]) {
destAddr = tun.addr
}
}
if neighbor, ok := tun.icmpv6.peermacs[destAddr]; ok && neighbor.learned {
peermac = neighbor.mac
peerknown = true
} else if neighbor, ok := tun.icmpv6.peermacs[tun.addr]; ok && neighbor.learned {
peermac = neighbor.mac
peerknown = true
sendndp(destAddr)
} else {
sendndp(tun.addr)
}
if peerknown {
var proto ethernet.Ethertype
switch {
case data[0]&0xf0 == 0x60:
proto = ethernet.IPv6
case data[0]&0xf0 == 0x40:
proto = ethernet.IPv4
}
var frame ethernet.Frame
frame.Prepare(
peermac[:6], // Destination MAC address
tun.icmpv6.mymac[:6], // Source MAC address
ethernet.NotTagged, // VLAN tagging
proto, // Ethertype
len(data)) // Payload length
copy(frame[tun_ETHER_HEADER_LENGTH:], data[:])
if _, err := tun.iface.Write(frame); err != nil {
tun.mutex.RLock()
open := tun.isOpen
tun.mutex.RUnlock()
if !open {
return nil
} else {
panic(err)
}
}
}
}
if neighbor, ok := tun.icmpv6.peermacs[destAddr]; ok && neighbor.learned {
peermac = neighbor.mac
peerknown = true
} else if neighbor, ok := tun.icmpv6.peermacs[tun.addr]; ok && neighbor.learned {
peermac = neighbor.mac
peerknown = true
sendndp(destAddr)
} else {
sendndp(tun.addr)
}
if peerknown {
var proto ethernet.Ethertype
switch {
case data[0]&0xf0 == 0x60:
proto = ethernet.IPv6
case data[0]&0xf0 == 0x40:
proto = ethernet.IPv4
}
var frame ethernet.Frame
frame.Prepare(
peermac[:6], // Destination MAC address
tun.icmpv6.mymac[:6], // Source MAC address
ethernet.NotTagged, // VLAN tagging
proto, // Ethertype
len(data)) // Payload length
copy(frame[tun_ETHER_HEADER_LENGTH:], data[:])
if _, err := tun.iface.Write(frame); err != nil {
if _, err := tun.iface.Write(data); err != nil {
tun.mutex.RLock()
open := tun.isOpen
tun.mutex.RUnlock()
@ -231,19 +270,8 @@ func (tun *TunAdapter) Write() error {
}
}
}
} else {
if _, err := tun.iface.Write(data); err != nil {
tun.mutex.RLock()
open := tun.isOpen
tun.mutex.RUnlock()
if !open {
return nil
} else {
panic(err)
}
}
util.PutBytes(data)
}
util.PutBytes(data)
}
}