Files
weave/types.go
T
Matthias Radestock 5b6dc2d762 (slightly) faster pmtu discovery
Issues with the previous scheme...

When we have just encountered an EMSGSIZE, the odds of encountering
another one straight away, when attemtping to send a verification
packet with the lower mtu, are slim, since for a new, lower mtu to be
set some packet must have made it further then the one that triggered
the icmp3.4 that gave rise to the EMSGSIZE, and we must have received
the resulting icmp3.4. All of which takes time.

Also, sending a bunch of udp packets in rapid succession is not a
great way to improve their chances of making it through to the other
peer, since they could easily all get dropped by a single congestion
event or other network glitch.

Now we send a single verification packet, wait for a short while, and
if we don't get a response then we send another one, wait for longer
period (2x), etc, until some upper bound is reached, at which point we
lower the pmtu and start the verification process again (same as
currently happens).

We are now also calling flush() to send the verification packet, just
as we do for ordinary packets. This makes for shorter code, consistent
error handling, and introduces a nice little recursion :)
2014-08-29 19:15:18 +01:00

305 lines
5.6 KiB
Go

package weave
import (
"bytes"
"code.google.com/p/go-bit/bit"
"code.google.com/p/gopacket"
"code.google.com/p/gopacket/layers"
"encoding/gob"
"net"
"sync"
"time"
)
type Router struct {
Ourself *Peer
Iface *net.Interface
PeersSubscribeChan chan<- chan<- map[string]Peer
Macs *MacCache
Peers *PeerCache
UDPListener *net.UDPConn
Topology *Topology
ConnectionMaker *ConnectionMaker
Password *[]byte
ConnLimit int
BufSz int
LogFrame func(string, []byte, *layers.Ethernet)
}
type Peer struct {
sync.RWMutex
Name PeerName
NameByte []byte
connections map[PeerName]Connection
version uint64
UID uint64
Router *Router
localRefCount uint64
queryChan chan<- *PeerInteraction
}
type PeerInteraction struct {
Interaction
payload interface{}
}
type Connection interface {
Local() *Peer
Remote() *Peer
RemoteTCPAddr() string
Established() bool
Shutdown()
}
type RemoteConnection struct {
local *Peer
remote *Peer
remoteTCPAddr string
}
type LocalConnection struct {
sync.RWMutex
RemoteConnection
TCPConn *net.TCPConn
tcpSender TCPSender
remoteUDPAddr *net.UDPAddr
established bool
stackFrag bool
effectivePMTU int
pmtuVerified bool
SessionKey *[32]byte
heartbeatStop chan<- interface{}
forwardChan chan<- *ForwardedFrame
forwardChanDF chan<- *ForwardedFrame
stopForward chan<- interface{}
stopForwardDF chan<- interface{}
Decryptor Decryptor
Router *Router
UID uint64
shutdown bool
queryChan chan<- *ConnectionInteraction
}
type ConnectionInteraction struct {
Interaction
payload interface{}
}
type Forwarder struct {
conn *LocalConnection
ch <-chan *ForwardedFrame
stop <-chan interface{}
pmtuVerifyTick <-chan time.Time
pmtuVerifyCount uint
enc Encryptor
udpSender UDPSender
maxPayload int
effectivePMTU int
}
type UDPPacket struct {
Name PeerName
Packet []byte
Sender *net.UDPAddr
}
type EthernetDecoder struct {
eth layers.Ethernet
ip layers.IPv4
decoded []gopacket.LayerType
parser *gopacket.DecodingLayerParser
}
type MsgTooBigError struct {
PMTU int // actual pmtu, i.e. what the kernel told us
}
type FrameTooBigError struct {
EPMTU int // effective pmtu, i.e. what we tell packet senders
}
type UnknownPeersError struct {
}
type NameCollisionError struct {
Name PeerName
}
type LocalAddress struct {
ip net.IP
network *net.IPNet
}
type ForwardedFrame struct {
srcPeer *Peer
dstPeer *Peer
frame []byte
}
type Interaction struct {
code int
resultChan chan<- interface{}
}
type Topology struct {
sync.RWMutex
queryChan chan<- *Interaction
unicast map[PeerName]PeerName
broadcast map[PeerName][]PeerName
router *Router
}
type ConnectionMakerInteraction struct {
Interaction
foundAt string
name PeerName
}
type ConnectionMaker struct {
router *Router
queryChan chan<- *ConnectionMakerInteraction
activeConnections map[string]string
failedConnections map[PeerName]*FailedConnection
}
type FailedConnection struct {
foundAt map[string]bool
tryAfter time.Time
tryInterval time.Duration
attemptCount int
}
// UDPSender interface and implementations
type UDPSender interface {
Send([]byte) error
Shutdown() error
}
type SimpleUDPSender struct {
conn *LocalConnection
udpConn *net.UDPConn
}
type RawUDPSender struct {
ipBuf gopacket.SerializeBuffer
opts gopacket.SerializeOptions
udpHeader *layers.UDP
socket *net.IPConn
conn *LocalConnection
}
// TCPSender interface and implementations
type TCPSender interface {
Send([]byte) error
}
type SimpleTCPSender struct {
encoder *gob.Encoder
}
type EncryptedTCPSender struct {
sync.RWMutex
outerEncoder *gob.Encoder
innerEncoder *gob.Encoder
buffer *bytes.Buffer
conn *LocalConnection
msgCount int
}
type EncryptedTCPMessage struct {
Number int
Body []byte
}
// TCPReceiver interface and implementations
type TCPReceiver interface {
Decode([]byte) ([]byte, error)
}
type SimpleTCPReceiver struct {
}
type EncryptedTCPReceiver struct {
conn *LocalConnection
decoder *gob.Decoder
buffer *bytes.Buffer
msgCount int
}
// Encryptor interface and implementations
type Encryptor interface {
FrameOverhead() int
PacketOverhead() int
IsEmpty() bool
Bytes() []byte
AppendFrame(*ForwardedFrame)
TotalLen() int
}
type NonEncryptor struct {
buf []byte
bufTail []byte
buffered int
prefixLen int
}
type NaClEncryptor struct {
NonEncryptor
buf []byte
offset uint16
nonce *[24]byte
nonceChan chan *[24]byte
flags uint16
prefixLen int
conn *LocalConnection
df bool
}
// Decryptor interface and implementations
type FrameConsumer func(*LocalConnection, *net.UDPAddr, []byte, []byte, uint16, []byte) error
type Decryptor interface {
IterateFrames(FrameConsumer, *UDPPacket) error
ReceiveNonce([]byte)
Shutdown()
}
type NonDecryptor struct {
conn *LocalConnection
}
type NaClDecryptor struct {
NonDecryptor
instance *NaClDecryptorInstance
instanceDF *NaClDecryptorInstance
}
type NaClDecryptorInstance struct {
nonce *[24]byte
previousNonce *[24]byte
usedOffsets *bit.Set
previousUsedOffsets *bit.Set
highestOffsetSeen uint16
nonceChan chan *[24]byte
}
// Packet capture/inject interfaces
type PacketSource interface {
ReadPacket() ([]byte, error)
}
type PacketSink interface {
WritePacket([]byte) error
}
type PacketSourceSink interface {
PacketSource
PacketSink
}