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move some logic from TunAdapter.reader into a new function, TunAdapter.readerPacketHandler

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This commit is contained in:
Arceliar 2019-07-28 23:33:04 -05:00
parent 38e1503b28
commit 406e143f7f
1 changed files with 178 additions and 173 deletions
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351
src/tuntap/iface.go
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@ -110,178 +110,10 @@ func (tun *TunAdapter) writer() error {
} }
} }
func (tun *TunAdapter) reader() error { // Run in a separate goroutine by the reader
recvd := make([]byte, 65535+tun_ETHER_HEADER_LENGTH) // Does all of the per-packet ICMP checks, passes packets to the right Conn worker
toWorker := make(chan []byte, 32) func (tun *TunAdapter) readerPacketHandler(ch chan []byte) {
defer close(toWorker) for recvd := range ch {
go func() {
for bs := range toWorker {
// If we detect an ICMP packet then hand it to the ICMPv6 module
if bs[6] == 58 {
// Found an ICMPv6 packet - we need to make sure to give ICMPv6 the full
// Ethernet frame rather than just the IPv6 packet as this is needed for
// NDP to work correctly
if err := tun.icmpv6.ParsePacket(recvd); err == nil {
// We acted on the packet in the ICMPv6 module so don't forward or do
// anything else with it
continue
}
}
// From the IP header, work out what our source and destination addresses
// and node IDs are. We will need these in order to work out where to send
// the packet
var srcAddr address.Address
var dstAddr address.Address
var dstNodeID *crypto.NodeID
var dstNodeIDMask *crypto.NodeID
var dstSnet address.Subnet
var addrlen int
n := len(bs)
// Check the IP protocol - if it doesn't match then we drop the packet and
// do nothing with it
if bs[0]&0xf0 == 0x60 {
// Check if we have a fully-sized IPv6 header
if len(bs) < 40 {
continue
}
// Check the packet size
if n-tun_IPv6_HEADER_LENGTH != 256*int(bs[4])+int(bs[5]) {
continue
}
// IPv6 address
addrlen = 16
copy(srcAddr[:addrlen], bs[8:])
copy(dstAddr[:addrlen], bs[24:])
copy(dstSnet[:addrlen/2], bs[24:])
} else if bs[0]&0xf0 == 0x40 {
// Check if we have a fully-sized IPv4 header
if len(bs) < 20 {
continue
}
// Check the packet size
if n != 256*int(bs[2])+int(bs[3]) {
continue
}
// IPv4 address
addrlen = 4
copy(srcAddr[:addrlen], bs[12:])
copy(dstAddr[:addrlen], bs[16:])
} else {
// Unknown address length or protocol, so drop the packet and ignore it
tun.log.Traceln("Unknown packet type, dropping")
continue
}
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
}
if !dstAddr.IsValid() && !dstSnet.IsValid() {
if key, err := tun.ckr.getPublicKeyForAddress(dstAddr, addrlen); err == nil {
// A public key was found, get the node ID for the search
dstNodeID = crypto.GetNodeID(&key)
// Do a quick check to ensure that the node ID refers to a vaild
// Yggdrasil address or subnet - this might be superfluous
addr := *address.AddrForNodeID(dstNodeID)
copy(dstAddr[:], addr[:])
copy(dstSnet[:], addr[:])
// Are we certain we looked up a valid node?
if !dstAddr.IsValid() && !dstSnet.IsValid() {
continue
}
} else {
// No public key was found in the CKR table so we've exhausted our options
continue
}
}
// Do we have an active connection for this node address?
tun.mutex.RLock()
session, isIn := tun.addrToConn[dstAddr]
if !isIn || session == nil {
session, isIn = tun.subnetToConn[dstSnet]
if !isIn || session == nil {
// Neither an address nor a subnet mapping matched, therefore populate
// the node ID and mask to commence a search
if dstAddr.IsValid() {
dstNodeID, dstNodeIDMask = dstAddr.GetNodeIDandMask()
} else {
dstNodeID, dstNodeIDMask = dstSnet.GetNodeIDandMask()
}
}
}
tun.mutex.RUnlock()
// If we don't have a connection then we should open one
if !isIn || session == nil {
// Check we haven't been given empty node ID, really this shouldn't ever
// happen but just to be sure...
if dstNodeID == nil || dstNodeIDMask == nil {
panic("Given empty dstNodeID and dstNodeIDMask - this shouldn't happen")
}
// Dial to the remote node
packet := bs
go func() {
// FIXME just spitting out a goroutine to do this is kind of ugly and means we drop packets until the dial finishes
tun.mutex.Lock()
_, known := tun.dials[*dstNodeID]
tun.dials[*dstNodeID] = append(tun.dials[*dstNodeID], packet)
for len(tun.dials[*dstNodeID]) > 32 {
util.PutBytes(tun.dials[*dstNodeID][0])
tun.dials[*dstNodeID] = tun.dials[*dstNodeID][1:]
}
tun.mutex.Unlock()
if known {
return
}
var tc *tunConn
if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
// We've been given a connection so prepare the session wrapper
if tc, err = tun.wrap(conn); err != nil {
// Something went wrong when storing the connection, typically that
// something already exists for this address or subnet
tun.log.Debugln("TUN/TAP iface wrap:", err)
}
}
tun.mutex.Lock()
packets := tun.dials[*dstNodeID]
delete(tun.dials, *dstNodeID)
tun.mutex.Unlock()
if tc != nil {
for _, packet := range packets {
select {
case tc.send <- packet:
default:
util.PutBytes(packet)
}
}
}
}()
// While the dial is going on we can't do much else
// continuing this iteration - skip to the next one
continue
}
// If we have a connection now, try writing to it
if isIn && session != nil {
packet := bs
select {
case session.send <- packet:
default:
util.PutBytes(packet)
}
}
}
}()
for {
// Wait for a packet to be delivered to us through the TUN/TAP adapter
n, err := tun.iface.Read(recvd)
if err != nil {
if !tun.isOpen {
return err
}
panic(err)
}
if n == 0 {
continue
}
// If it's a TAP adapter, update the buffer slice so that we no longer // If it's a TAP adapter, update the buffer slice so that we no longer
// include the ethernet headers // include the ethernet headers
offset := 0 offset := 0
@ -295,7 +127,180 @@ func (tun *TunAdapter) reader() error {
} }
// Offset the buffer from now on so that we can ignore ethernet frames if // Offset the buffer from now on so that we can ignore ethernet frames if
// they are present // they are present
bs := append(util.GetBytes(), recvd[offset:offset+n]...) bs := recvd[offset:]
// If we detect an ICMP packet then hand it to the ICMPv6 module
if bs[6] == 58 {
// Found an ICMPv6 packet - we need to make sure to give ICMPv6 the full
// Ethernet frame rather than just the IPv6 packet as this is needed for
// NDP to work correctly
if err := tun.icmpv6.ParsePacket(recvd); err == nil {
// We acted on the packet in the ICMPv6 module so don't forward or do
// anything else with it
continue
}
}
// Shift forward to avoid leaking bytes off the front of the slide when we eventually store it
bs = append(recvd[:0], bs...)
// From the IP header, work out what our source and destination addresses
// and node IDs are. We will need these in order to work out where to send
// the packet
var srcAddr address.Address
var dstAddr address.Address
var dstNodeID *crypto.NodeID
var dstNodeIDMask *crypto.NodeID
var dstSnet address.Subnet
var addrlen int
n := len(bs)
// Check the IP protocol - if it doesn't match then we drop the packet and
// do nothing with it
if bs[0]&0xf0 == 0x60 {
// Check if we have a fully-sized IPv6 header
if len(bs) < 40 {
continue
}
// Check the packet size
if n-tun_IPv6_HEADER_LENGTH != 256*int(bs[4])+int(bs[5]) {
continue
}
// IPv6 address
addrlen = 16
copy(srcAddr[:addrlen], bs[8:])
copy(dstAddr[:addrlen], bs[24:])
copy(dstSnet[:addrlen/2], bs[24:])
} else if bs[0]&0xf0 == 0x40 {
// Check if we have a fully-sized IPv4 header
if len(bs) < 20 {
continue
}
// Check the packet size
if n != 256*int(bs[2])+int(bs[3]) {
continue
}
// IPv4 address
addrlen = 4
copy(srcAddr[:addrlen], bs[12:])
copy(dstAddr[:addrlen], bs[16:])
} else {
// Unknown address length or protocol, so drop the packet and ignore it
tun.log.Traceln("Unknown packet type, dropping")
continue
}
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
}
if !dstAddr.IsValid() && !dstSnet.IsValid() {
if key, err := tun.ckr.getPublicKeyForAddress(dstAddr, addrlen); err == nil {
// A public key was found, get the node ID for the search
dstNodeID = crypto.GetNodeID(&key)
// Do a quick check to ensure that the node ID refers to a vaild
// Yggdrasil address or subnet - this might be superfluous
addr := *address.AddrForNodeID(dstNodeID)
copy(dstAddr[:], addr[:])
copy(dstSnet[:], addr[:])
// Are we certain we looked up a valid node?
if !dstAddr.IsValid() && !dstSnet.IsValid() {
continue
}
} else {
// No public key was found in the CKR table so we've exhausted our options
continue
}
}
// Do we have an active connection for this node address?
tun.mutex.RLock()
session, isIn := tun.addrToConn[dstAddr]
if !isIn || session == nil {
session, isIn = tun.subnetToConn[dstSnet]
if !isIn || session == nil {
// Neither an address nor a subnet mapping matched, therefore populate
// the node ID and mask to commence a search
if dstAddr.IsValid() {
dstNodeID, dstNodeIDMask = dstAddr.GetNodeIDandMask()
} else {
dstNodeID, dstNodeIDMask = dstSnet.GetNodeIDandMask()
}
}
}
tun.mutex.RUnlock()
// If we don't have a connection then we should open one
if !isIn || session == nil {
// Check we haven't been given empty node ID, really this shouldn't ever
// happen but just to be sure...
if dstNodeID == nil || dstNodeIDMask == nil {
panic("Given empty dstNodeID and dstNodeIDMask - this shouldn't happen")
}
// Dial to the remote node
go func() {
// FIXME just spitting out a goroutine to do this is kind of ugly and means we drop packets until the dial finishes
tun.mutex.Lock()
_, known := tun.dials[*dstNodeID]
tun.dials[*dstNodeID] = append(tun.dials[*dstNodeID], bs)
for len(tun.dials[*dstNodeID]) > 32 {
util.PutBytes(tun.dials[*dstNodeID][0])
tun.dials[*dstNodeID] = tun.dials[*dstNodeID][1:]
}
tun.mutex.Unlock()
if known {
return
}
var tc *tunConn
if conn, err := tun.dialer.DialByNodeIDandMask(dstNodeID, dstNodeIDMask); err == nil {
// We've been given a connection so prepare the session wrapper
if tc, err = tun.wrap(conn); err != nil {
// Something went wrong when storing the connection, typically that
// something already exists for this address or subnet
tun.log.Debugln("TUN/TAP iface wrap:", err)
}
}
tun.mutex.Lock()
packets := tun.dials[*dstNodeID]
delete(tun.dials, *dstNodeID)
tun.mutex.Unlock()
if tc != nil {
for _, packet := range packets {
select {
case tc.send <- packet:
default:
util.PutBytes(packet)
}
}
}
}()
// While the dial is going on we can't do much else
// continuing this iteration - skip to the next one
continue
}
// If we have a connection now, try writing to it
if isIn && session != nil {
select {
case session.send <- bs:
default:
util.PutBytes(bs)
}
}
}
}
func (tun *TunAdapter) reader() error {
recvd := make([]byte, 65535+tun_ETHER_HEADER_LENGTH)
toWorker := make(chan []byte, 32)
defer close(toWorker)
go tun.readerPacketHandler(toWorker)
for {
// Wait for a packet to be delivered to us through the TUN/TAP adapter
n, err := tun.iface.Read(recvd)
if err != nil {
if !tun.isOpen {
return err
}
panic(err)
}
if n == 0 {
continue
}
bs := append(util.GetBytes(), recvd[:n]...)
toWorker <- bs toWorker <- bs
} }
} }