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Fix TAP mode

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This commit is contained in:
Neil Alexander 2019-07-06 15:08:17 +01:00
parent 912c181581
commit e8272926a4
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
4 changed files with 88 additions and 53 deletions
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3
src/tuntap/ckr.go
View File

@ -48,8 +48,11 @@ func (c *cryptokey) init(tun *TunAdapter) {
}
}()
c.tun.log.Debugln("Configuring CKR...")
if err := c.configure(); err != nil {
c.tun.log.Errorln("CKR configuration failed:", err)
} else {
c.tun.log.Debugln("CKR configured")
}
}

94
src/tuntap/icmpv6.go
View File

@ -13,6 +13,7 @@ import (
"encoding/binary"
"errors"
"net"
"sync"
"time"
"golang.org/x/net/icmp"
@ -21,19 +22,18 @@ import (
"github.com/yggdrasil-network/yggdrasil-go/src/address"
)
type macAddress [6]byte
const len_ETHER = 14
type ICMPv6 struct {
tun *TunAdapter
mylladdr net.IP
mymac macAddress
peermacs map[address.Address]neighbor
tun *TunAdapter
mylladdr net.IP
mymac net.HardwareAddr
peermacs map[address.Address]neighbor
peermacsmutex sync.RWMutex
}
type neighbor struct {
mac macAddress
mac net.HardwareAddr
learned bool
lastadvertisement time.Time
lastsolicitation time.Time
@ -61,10 +61,12 @@ func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
// addresses.
func (i *ICMPv6) Init(t *TunAdapter) {
i.tun = t
i.peermacsmutex.Lock()
i.peermacs = make(map[address.Address]neighbor)
i.peermacsmutex.Unlock()
// Our MAC address and link-local address
i.mymac = macAddress{
i.mymac = net.HardwareAddr{
0x02, 0x00, 0x00, 0x00, 0x00, 0x02}
i.mylladdr = net.IP{
0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@ -181,16 +183,30 @@ func (i *ICMPv6) UnmarshalPacket(datain []byte, datamac *[]byte) ([]byte, error)
if datamac != nil {
var addr address.Address
var target address.Address
var mac macAddress
mac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
copy(addr[:], ipv6Header.Src[:])
copy(target[:], datain[48:64])
copy(mac[:], (*datamac)[:])
// fmt.Printf("Learning peer MAC %x for %x\n", mac, target)
i.peermacsmutex.Lock()
neighbor := i.peermacs[target]
neighbor.mac = mac
neighbor.learned = true
neighbor.lastadvertisement = time.Now()
i.peermacs[target] = neighbor
i.peermacsmutex.Unlock()
i.tun.log.Debugln("Learned peer MAC", mac.String(), "for", net.IP(target[:]).String())
/*
i.tun.log.Debugln("Peer MAC table:")
i.peermacsmutex.RLock()
for t, n := range i.peermacs {
if n.learned {
i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "has MAC", n.mac.String())
} else {
i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "is not learned yet")
}
}
i.peermacsmutex.RUnlock()
*/
}
return nil, errors.New("No response needed")
}
@ -201,7 +217,7 @@ func (i *ICMPv6) UnmarshalPacket(datain []byte, datamac *[]byte) ([]byte, error)
// Creates an ICMPv6 packet based on the given icmp.MessageBody and other
// parameters, complete with ethernet and IP headers, which can be written
// directly to a TAP adapter.
func (i *ICMPv6) CreateICMPv6L2(dstmac macAddress, dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
func (i *ICMPv6) CreateICMPv6L2(dstmac net.HardwareAddr, dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
// Pass through to CreateICMPv6
ipv6packet, err := CreateICMPv6(dst, src, mtype, mcode, mbody)
if err != nil {
@ -264,13 +280,46 @@ func CreateICMPv6(dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody
return responsePacket, nil
}
func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
func (i *ICMPv6) Solicit(addr address.Address) {
retries := 5
for retries > 0 {
retries--
i.peermacsmutex.RLock()
if n, ok := i.peermacs[addr]; ok && n.learned {
i.tun.log.Debugln("MAC learned for", net.IP(addr[:]).String())
i.peermacsmutex.RUnlock()
return
}
i.peermacsmutex.RUnlock()
i.tun.log.Debugln("Sending neighbor solicitation for", net.IP(addr[:]).String())
i.peermacsmutex.Lock()
if n, ok := i.peermacs[addr]; !ok {
i.peermacs[addr] = neighbor{
lastsolicitation: time.Now(),
}
} else {
n.lastsolicitation = time.Now()
}
i.peermacsmutex.Unlock()
request, err := i.createNDPL2(addr)
if err != nil {
panic(err)
}
if _, err := i.tun.iface.Write(request); err != nil {
panic(err)
}
i.tun.log.Debugln("Sent neighbor solicitation for", net.IP(addr[:]).String())
time.Sleep(time.Second)
}
}
func (i *ICMPv6) createNDPL2(dst address.Address) ([]byte, error) {
// Create the ND payload
var payload [28]byte
copy(payload[:4], []byte{0x00, 0x00, 0x00, 0x00})
copy(payload[4:20], dst[:])
copy(payload[20:22], []byte{0x01, 0x01})
copy(payload[22:28], i.mymac[:6])
copy(payload[:4], []byte{0x00, 0x00, 0x00, 0x00}) // Flags
copy(payload[4:20], dst[:]) // Destination
copy(payload[20:22], []byte{0x01, 0x01}) // Type & length
copy(payload[22:28], i.mymac[:6]) // Link layer address
// Create the ICMPv6 solicited-node address
var dstaddr address.Address
@ -281,7 +330,7 @@ func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
copy(dstaddr[13:], dst[13:16])
// Create the multicast MAC
var dstmac macAddress
dstmac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
copy(dstmac[:2], []byte{0x33, 0x33})
copy(dstmac[2:6], dstaddr[12:16])
@ -293,9 +342,6 @@ func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
if err != nil {
return nil, err
}
neighbor := i.peermacs[dstaddr]
neighbor.lastsolicitation = time.Now()
i.peermacs[dstaddr] = neighbor
return requestPacket, nil
}
@ -319,10 +365,10 @@ func (i *ICMPv6) HandleNDP(in []byte) ([]byte, error) {
// Create our NDP message body response
body := make([]byte, 28)
binary.BigEndian.PutUint32(body[:4], uint32(0x20000000))
copy(body[4:20], in[8:24]) // Target address
body[20] = uint8(2)
body[21] = uint8(1)
binary.BigEndian.PutUint32(body[:4], uint32(0x40000000)) // Flags
copy(body[4:20], in[8:24]) // Target address
body[20] = uint8(2) // Type: Target link-layer address
body[21] = uint8(1) // Length: 1x address (8 bytes)
copy(body[22:28], i.mymac[:6])
// Send it back

25
src/tuntap/iface.go
View File

@ -3,6 +3,7 @@ package tuntap
import (
"bytes"
"errors"
"net"
"time"
"github.com/songgao/packets/ethernet"
@ -43,19 +44,10 @@ func (tun *TunAdapter) writer() error {
neigh, known := tun.icmpv6.peermacs[dstAddr]
known = known && (time.Since(neigh.lastsolicitation).Seconds() < 30)
if !known {
request, err := tun.icmpv6.CreateNDPL2(dstAddr)
if err != nil {
panic(err)
}
if _, err := tun.iface.Write(request); err != nil {
panic(err)
}
tun.icmpv6.peermacs[dstAddr] = neighbor{
lastsolicitation: time.Now(),
}
tun.icmpv6.Solicit(dstAddr)
}
}
var peermac macAddress
peermac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
var peerknown bool
if b[0]&0xf0 == 0x40 {
dstAddr = tun.addr
@ -65,14 +57,19 @@ func (tun *TunAdapter) writer() error {
}
}
if neighbor, ok := tun.icmpv6.peermacs[dstAddr]; ok && neighbor.learned {
// If we've learned the MAC of a 300::/7 address, for example, or a CKR
// address, use the MAC address of that
peermac = neighbor.mac
peerknown = true
} else if neighbor, ok := tun.icmpv6.peermacs[tun.addr]; ok && neighbor.learned {
// Otherwise send directly to the MAC address of the host if that's
// known instead
peermac = neighbor.mac
peerknown = true
sendndp(dstAddr)
} else {
// Nothing has been discovered, try to discover the destination
sendndp(tun.addr)
}
if peerknown {
var proto ethernet.Ethertype
@ -92,6 +89,8 @@ func (tun *TunAdapter) writer() error {
copy(frame[tun_ETHER_HEADER_LENGTH:], b[:n])
n += tun_ETHER_HEADER_LENGTH
w, err = tun.iface.Write(frame[:n])
} else {
tun.log.Errorln("TUN/TAP iface write error: no peer MAC known for", net.IP(dstAddr[:]).String(), "- dropping packet")
}
} else {
w, err = tun.iface.Write(b[:n])
@ -184,7 +183,7 @@ func (tun *TunAdapter) reader() error {
// Unknown address length or protocol, so drop the packet and ignore it
continue
}
if !tun.ckr.isValidSource(srcAddr, addrlen) {
if tun.ckr.isEnabled() && !tun.ckr.isValidSource(srcAddr, addrlen) {
// The packet had a source address that doesn't belong to us or our
// configured crypto-key routing source subnets
continue

19
src/tuntap/tun.go
View File

@ -14,7 +14,6 @@ import (
"fmt"
"net"
"sync"
"time"
"github.com/gologme/log"
"github.com/yggdrasil-network/water"
@ -152,21 +151,6 @@ func (tun *TunAdapter) Start() error {
tun.send = make(chan []byte, 32) // TODO: is this a sensible value?
tun.reconfigure = make(chan chan error)
tun.mutex.Unlock()
if iftapmode {
go func() {
for {
if _, ok := tun.icmpv6.peermacs[tun.addr]; ok {
break
}
request, err := tun.icmpv6.CreateNDPL2(tun.addr)
if err != nil {
panic(err)
}
tun.send <- request
time.Sleep(time.Second)
}
}()
}
go func() {
for {
e := <-tun.reconfigure
@ -177,6 +161,9 @@ func (tun *TunAdapter) Start() error {
go tun.reader()
go tun.writer()
tun.icmpv6.Init(tun)
if iftapmode {
go tun.icmpv6.Solicit(tun.addr)
}
tun.ckr.init(tun)
return nil
}