yggdrasil-go/src/yggdrasil/link.go
2019-08-24 12:55:49 -05:00

420 lines
12 KiB
Go

package yggdrasil
import (
"encoding/hex"
"errors"
"fmt"
"io"
"net"
"net/url"
"strings"
"sync"
//"sync/atomic"
"time"
"github.com/yggdrasil-network/yggdrasil-go/src/address"
"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
"github.com/yggdrasil-network/yggdrasil-go/src/util"
)
type link struct {
core *Core
reconfigure chan chan error
mutex sync.RWMutex // protects interfaces below
interfaces map[linkInfo]*linkInterface
tcp tcp // TCP interface support
// TODO timeout (to remove from switch), read from config.ReadTimeout
}
type linkInfo struct {
box crypto.BoxPubKey // Their encryption key
sig crypto.SigPubKey // Their signing key
linkType string // Type of link, e.g. TCP, AWDL
local string // Local name or address
remote string // Remote name or address
}
type linkInterfaceMsgIO interface {
readMsg() ([]byte, error)
writeMsgs([][]byte) (int, error)
close() error
// These are temporary workarounds to stream semantics
_sendMetaBytes([]byte) error
_recvMetaBytes() ([]byte, error)
}
type linkInterface struct {
name string
link *link
peer *peer
msgIO linkInterfaceMsgIO
info linkInfo
incoming bool
force bool
closed chan struct{}
}
func (l *link) init(c *Core) error {
l.core = c
l.mutex.Lock()
l.interfaces = make(map[linkInfo]*linkInterface)
l.reconfigure = make(chan chan error)
l.mutex.Unlock()
if err := l.tcp.init(l); err != nil {
c.log.Errorln("Failed to start TCP interface")
return err
}
go func() {
for {
e := <-l.reconfigure
tcpresponse := make(chan error)
l.tcp.reconfigure <- tcpresponse
if err := <-tcpresponse; err != nil {
e <- err
continue
}
e <- nil
}
}()
return nil
}
func (l *link) call(uri string, sintf string) error {
u, err := url.Parse(uri)
if err != nil {
return err
}
pathtokens := strings.Split(strings.Trim(u.Path, "/"), "/")
switch u.Scheme {
case "tcp":
l.tcp.call(u.Host, nil, sintf)
case "socks":
l.tcp.call(pathtokens[0], u.Host, sintf)
default:
return errors.New("unknown call scheme: " + u.Scheme)
}
return nil
}
func (l *link) listen(uri string) error {
u, err := url.Parse(uri)
if err != nil {
return err
}
switch u.Scheme {
case "tcp":
_, err := l.tcp.listen(u.Host)
return err
default:
return errors.New("unknown listen scheme: " + u.Scheme)
}
}
func (l *link) create(msgIO linkInterfaceMsgIO, name, linkType, local, remote string, incoming, force bool) (*linkInterface, error) {
// Technically anything unique would work for names, but lets pick something human readable, just for debugging
intf := linkInterface{
name: name,
link: l,
msgIO: msgIO,
info: linkInfo{
linkType: linkType,
local: local,
remote: remote,
},
incoming: incoming,
force: force,
}
return &intf, nil
}
func (intf *linkInterface) handler() error {
// TODO split some of this into shorter functions, so it's easier to read, and for the FIXME duplicate peer issue mentioned later
myLinkPub, myLinkPriv := crypto.NewBoxKeys()
meta := version_getBaseMetadata()
meta.box = intf.link.core.boxPub
meta.sig = intf.link.core.sigPub
meta.link = *myLinkPub
metaBytes := meta.encode()
// TODO timeouts on send/recv (goroutine for send/recv, channel select w/ timer)
var err error
if !util.FuncTimeout(func() { err = intf.msgIO._sendMetaBytes(metaBytes) }, 30*time.Second) {
return errors.New("timeout on metadata send")
}
if err != nil {
return err
}
if !util.FuncTimeout(func() { metaBytes, err = intf.msgIO._recvMetaBytes() }, 30*time.Second) {
return errors.New("timeout on metadata recv")
}
if err != nil {
return err
}
meta = version_metadata{}
if !meta.decode(metaBytes) || !meta.check() {
return errors.New("failed to decode metadata")
}
base := version_getBaseMetadata()
if meta.ver > base.ver || meta.ver == base.ver && meta.minorVer > base.minorVer {
intf.link.core.log.Errorln("Failed to connect to node: " + intf.name + " version: " + fmt.Sprintf("%d.%d", meta.ver, meta.minorVer))
return errors.New("failed to connect: wrong version")
}
// Check if we're authorized to connect to this key / IP
if intf.incoming && !intf.force && !intf.link.core.peers.isAllowedEncryptionPublicKey(&meta.box) {
intf.link.core.log.Warnf("%s connection from %s forbidden: AllowedEncryptionPublicKeys does not contain key %s",
strings.ToUpper(intf.info.linkType), intf.info.remote, hex.EncodeToString(meta.box[:]))
intf.msgIO.close()
return nil
}
// Check if we already have a link to this node
intf.info.box = meta.box
intf.info.sig = meta.sig
intf.link.mutex.Lock()
if oldIntf, isIn := intf.link.interfaces[intf.info]; isIn {
intf.link.mutex.Unlock()
// FIXME we should really return an error and let the caller block instead
// That lets them do things like close connections on its own, avoid printing a connection message in the first place, etc.
intf.link.core.log.Debugln("DEBUG: found existing interface for", intf.name)
intf.msgIO.close()
if !intf.incoming {
// Block outgoing connection attempts until the existing connection closes
<-oldIntf.closed
}
return nil
} else {
intf.closed = make(chan struct{})
intf.link.interfaces[intf.info] = intf
defer func() {
intf.link.mutex.Lock()
delete(intf.link.interfaces, intf.info)
intf.link.mutex.Unlock()
close(intf.closed)
}()
intf.link.core.log.Debugln("DEBUG: registered interface for", intf.name)
}
intf.link.mutex.Unlock()
// Create peer
shared := crypto.GetSharedKey(myLinkPriv, &meta.link)
intf.peer = intf.link.core.peers.newPeer(&meta.box, &meta.sig, shared, intf, func() { intf.msgIO.close() })
if intf.peer == nil {
return errors.New("failed to create peer")
}
defer func() {
// More cleanup can go here
intf.link.core.peers.removePeer(intf.peer.port)
}()
// Finish setting up the peer struct
out := make(chan [][]byte, 1)
defer close(out)
intf.peer.out = func(msgs [][]byte) {
defer func() { recover() }()
out <- msgs
}
intf.peer.linkOut = make(chan []byte, 1)
themAddr := address.AddrForNodeID(crypto.GetNodeID(&intf.info.box))
themAddrString := net.IP(themAddr[:]).String()
themString := fmt.Sprintf("%s@%s", themAddrString, intf.info.remote)
intf.link.core.log.Infof("Connected %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
// Start the link loop
go intf.peer.linkLoop()
// Start the writer
signalReady := make(chan struct{}, 1)
signalSent := make(chan bool, 1)
sendAck := make(chan struct{}, 1)
sendBlocked := time.NewTimer(time.Second)
defer util.TimerStop(sendBlocked)
util.TimerStop(sendBlocked)
go func() {
defer close(signalReady)
defer close(signalSent)
interval := 4 * time.Second
tcpTimer := time.NewTimer(interval) // used for backwards compat with old tcp
defer util.TimerStop(tcpTimer)
send := func(bss [][]byte) {
sendBlocked.Reset(time.Second)
size, _ := intf.msgIO.writeMsgs(bss)
util.TimerStop(sendBlocked)
select {
case signalSent <- size > 0:
default:
}
}
for {
// First try to send any link protocol traffic
select {
case msg := <-intf.peer.linkOut:
send([][]byte{msg})
continue
default:
}
// No protocol traffic to send, so reset the timer
util.TimerStop(tcpTimer)
tcpTimer.Reset(interval)
// Now block until something is ready or the timer triggers keepalive traffic
select {
case <-tcpTimer.C:
intf.link.core.log.Tracef("Sending (legacy) keep-alive to %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
send([][]byte{nil})
case <-sendAck:
intf.link.core.log.Tracef("Sending ack to %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
send([][]byte{nil})
case msg := <-intf.peer.linkOut:
send([][]byte{msg})
case msgs, ok := <-out:
if !ok {
return
}
send(msgs)
for _, msg := range msgs {
util.PutBytes(msg)
}
select {
case signalReady <- struct{}{}:
default:
}
//intf.link.core.log.Tracef("Sending packet to %s: %s, source %s",
// strings.ToUpper(intf.info.linkType), themString, intf.info.local)
}
}
}()
//intf.link.core.switchTable.idleIn <- intf.peer.port // notify switch that we're idle
// Used to enable/disable activity in the switch
signalAlive := make(chan bool, 1) // True = real packet, false = keep-alive
defer close(signalAlive)
ret := make(chan error, 1) // How we signal the return value when multiple goroutines are involved
go func() {
var isAlive bool
var isReady bool
var sendTimerRunning bool
var recvTimerRunning bool
recvTime := 6 * time.Second // TODO set to ReadTimeout from the config, reset if it gets changed
closeTime := 2 * switch_timeout // TODO or maybe this makes more sense for ReadTimeout?...
sendTime := time.Second
sendTimer := time.NewTimer(sendTime)
defer util.TimerStop(sendTimer)
recvTimer := time.NewTimer(recvTime)
defer util.TimerStop(recvTimer)
closeTimer := time.NewTimer(closeTime)
defer util.TimerStop(closeTimer)
for {
//intf.link.core.log.Debugf("State of %s: %s, source %s :: isAlive %t isReady %t sendTimerRunning %t recvTimerRunning %t",
// strings.ToUpper(intf.info.linkType), themString, intf.info.local,
// isAlive, isReady, sendTimerRunning, recvTimerRunning)
select {
case gotMsg, ok := <-signalAlive:
if !ok {
return
}
util.TimerStop(closeTimer)
closeTimer.Reset(closeTime)
util.TimerStop(recvTimer)
recvTimerRunning = false
isAlive = true
if !isReady {
// (Re-)enable in the switch
intf.link.core.switchTable.idleIn <- intf.peer.port
isReady = true
}
if gotMsg && !sendTimerRunning {
// We got a message
// Start a timer, if it expires then send a 0-sized ack to let them know we're alive
util.TimerStop(sendTimer)
sendTimer.Reset(sendTime)
sendTimerRunning = true
}
if !gotMsg {
intf.link.core.log.Tracef("Received ack from %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
}
case sentMsg, ok := <-signalSent:
// Stop any running ack timer
if !ok {
return
}
util.TimerStop(sendTimer)
sendTimerRunning = false
if sentMsg && !recvTimerRunning {
// We sent a message
// Start a timer, if it expires and we haven't gotten any return traffic (including a 0-sized ack), then assume there's a problem
util.TimerStop(recvTimer)
recvTimer.Reset(recvTime)
recvTimerRunning = true
}
case _, ok := <-signalReady:
if !ok {
return
}
if !isAlive {
// Disable in the switch
isReady = false
} else {
// Keep enabled in the switch
intf.link.core.switchTable.idleIn <- intf.peer.port
isReady = true
}
case <-sendBlocked.C:
// We blocked while trying to send something
isReady = false
intf.link.core.switchTable.blockPeer(intf.peer.port)
case <-sendTimer.C:
// We haven't sent anything, so signal a send of a 0 packet to let them know we're alive
select {
case sendAck <- struct{}{}:
default:
}
case <-recvTimer.C:
// We haven't received anything, so assume there's a problem and don't return this node to the switch until they start responding
isAlive = false
intf.link.core.switchTable.blockPeer(intf.peer.port)
case <-closeTimer.C:
// We haven't received anything in a really long time, so things have died at the switch level and then some...
// Just close the connection at this point...
select {
case ret <- errors.New("timeout"):
default:
}
intf.msgIO.close()
}
}
}()
// Run reader loop
for {
msg, err := intf.msgIO.readMsg()
if len(msg) > 0 {
// TODO rewrite this if the link becomes an actor
<-intf.peer.SyncExec(func() { intf.peer._handlePacket(msg) })
}
if err != nil {
if err != io.EOF {
select {
case ret <- err:
default:
}
}
break
}
select {
case signalAlive <- len(msg) > 0:
default:
}
}
////////////////////////////////////////////////////////////////////////////////
// Remember to set `err` to something useful before returning
select {
case err = <-ret:
intf.link.core.log.Infof("Disconnected %s: %s, source %s; error: %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local, err)
default:
err = nil
intf.link.core.log.Infof("Disconnected %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
}
return err
}