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link.go
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link.go
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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"
"golang.org/x/net/proxy"
"github.com/Arceliar/phony"
)
type links struct {
core *Core
mutex sync.RWMutex // protects links below
links map[linkInfo]*link
tcp tcp // TCP interface support
stopped chan struct{}
// 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 linkMsgIO interface {
readMsg() ([]byte, error)
writeMsgs([][]byte) (int, error)
close() error
// These are temporary workarounds to stream semantics
_sendMetaBytes([]byte) error
_recvMetaBytes() ([]byte, error)
}
type link struct {
lname string
links *links
peer *peer
options linkOptions
msgIO linkMsgIO
info linkInfo
incoming bool
force bool
closed chan struct{}
reader linkReader // Reads packets, notifies this link, passes packets to switch
writer linkWriter // Writes packets, notifies this link
phony.Inbox // Protects the below
sendTimer *time.Timer // Fires to signal that sending is blocked
keepAliveTimer *time.Timer // Fires to send keep-alive traffic
stallTimer *time.Timer // Fires to signal that no incoming traffic (including keep-alive) has been seen
closeTimer *time.Timer // Fires when the link has been idle so long we need to close it
readUnblocked bool // True if we've sent a read message unblocking this peer in the switch
writeUnblocked bool // True if we've sent a write message unblocking this peer in the swithc
shutdown bool // True if we're shutting down, avoids sending some messages that could race with new peers being crated in the same port
}
type linkOptions struct {
pinnedCurve25519Keys map[crypto.BoxPubKey]struct{}
pinnedEd25519Keys map[crypto.SigPubKey]struct{}
}
func (l *links) init(c *Core) error {
l.core = c
l.mutex.Lock()
l.links = make(map[linkInfo]*link)
l.mutex.Unlock()
l.stopped = make(chan struct{})
if err := l.tcp.init(l); err != nil {
c.log.Errorln("Failed to start TCP interface")
return err
}
return nil
}
func (l *links) reconfigure() {
l.tcp.reconfigure()
}
func (l *links) call(uri string, sintf string) error {
u, err := url.Parse(uri)
if err != nil {
return fmt.Errorf("peer %s is not correctly formatted (%s)", uri, err)
}
pathtokens := strings.Split(strings.Trim(u.Path, "/"), "/")
tcpOpts := tcpOptions{}
if pubkeys, ok := u.Query()["curve25519"]; ok && len(pubkeys) > 0 {
tcpOpts.pinnedCurve25519Keys = make(map[crypto.BoxPubKey]struct{})
for _, pubkey := range pubkeys {
if boxPub, err := hex.DecodeString(pubkey); err == nil {
var boxPubKey crypto.BoxPubKey
copy(boxPubKey[:], boxPub)
tcpOpts.pinnedCurve25519Keys[boxPubKey] = struct{}{}
}
}
}
if pubkeys, ok := u.Query()["ed25519"]; ok && len(pubkeys) > 0 {
tcpOpts.pinnedEd25519Keys = make(map[crypto.SigPubKey]struct{})
for _, pubkey := range pubkeys {
if sigPub, err := hex.DecodeString(pubkey); err == nil {
var sigPubKey crypto.SigPubKey
copy(sigPubKey[:], sigPub)
tcpOpts.pinnedEd25519Keys[sigPubKey] = struct{}{}
}
}
}
switch u.Scheme {
case "tcp":
l.tcp.call(u.Host, tcpOpts, sintf)
case "socks":
tcpOpts.socksProxyAddr = u.Host
if u.User != nil {
tcpOpts.socksProxyAuth = &proxy.Auth{}
tcpOpts.socksProxyAuth.User = u.User.Username()
tcpOpts.socksProxyAuth.Password, _ = u.User.Password()
}
l.tcp.call(pathtokens[0], tcpOpts, sintf)
case "tls":
tcpOpts.upgrade = l.tcp.tls.forDialer
l.tcp.call(u.Host, tcpOpts, sintf)
default:
return errors.New("unknown call scheme: " + u.Scheme)
}
return nil
}
func (l *links) listen(uri string) error {
u, err := url.Parse(uri)
if err != nil {
return fmt.Errorf("listener %s is not correctly formatted (%s)", uri, err)
}
switch u.Scheme {
case "tcp":
_, err := l.tcp.listen(u.Host, nil)
return err
case "tls":
_, err := l.tcp.listen(u.Host, l.tcp.tls.forListener)
return err
default:
return errors.New("unknown listen scheme: " + u.Scheme)
}
}
func (l *links) create(msgIO linkMsgIO, name, linkType, local, remote string, incoming, force bool, options linkOptions) (*link, error) {
// Technically anything unique would work for names, but let's pick something human readable, just for debugging
intf := link{
lname: name,
links: l,
options: options,
msgIO: msgIO,
info: linkInfo{
linkType: linkType,
local: local,
remote: remote,
},
incoming: incoming,
force: force,
}
intf.writer.intf = &intf
intf.writer.worker = make(chan [][]byte, 1)
intf.reader.intf = &intf
intf.reader.err = make(chan error)
return &intf, nil
}
func (l *links) stop() error {
close(l.stopped)
if err := l.tcp.stop(); err != nil {
return err
}
return nil
}
func (intf *link) handler() (chan struct{}, error) {
// TODO split some of this into shorter functions, so it's easier to read, and for the FIXME duplicate peer issue mentioned later
go func() {
for bss := range intf.writer.worker {
intf.msgIO.writeMsgs(bss)
}
}()
defer intf.writer.Act(nil, func() {
intf.writer.closed = true
close(intf.writer.worker)
})
myLinkPub, myLinkPriv := crypto.NewBoxKeys()
meta := version_getBaseMetadata()
meta.box = intf.links.core.boxPub
meta.sig = intf.links.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 nil, errors.New("timeout on metadata send")
}
if err != nil {
return nil, err
}
if !util.FuncTimeout(func() { metaBytes, err = intf.msgIO._recvMetaBytes() }, 30*time.Second) {
return nil, errors.New("timeout on metadata recv")
}
if err != nil {
return nil, err
}
meta = version_metadata{}
if !meta.decode(metaBytes) || !meta.check() {
return nil, errors.New("failed to decode metadata")
}
base := version_getBaseMetadata()
if meta.ver > base.ver || meta.ver == base.ver && meta.minorVer > base.minorVer {
intf.links.core.log.Errorln("Failed to connect to node: " + intf.lname + " version: " + fmt.Sprintf("%d.%d", meta.ver, meta.minorVer))
return nil, errors.New("failed to connect: wrong version")
}
// Check if the remote side matches the keys we expected. This is a bit of a weak
// check - in future versions we really should check a signature or something like that.
if pinned := intf.options.pinnedCurve25519Keys; pinned != nil {
if _, allowed := pinned[meta.box]; !allowed {
intf.links.core.log.Errorf("Failed to connect to node: %q sent curve25519 key that does not match pinned keys", intf.name)
return nil, fmt.Errorf("failed to connect: host sent curve25519 key that does not match pinned keys")
}
}
if pinned := intf.options.pinnedEd25519Keys; pinned != nil {
if _, allowed := pinned[meta.sig]; !allowed {
intf.links.core.log.Errorf("Failed to connect to node: %q sent ed25519 key that does not match pinned keys", intf.name)
return nil, fmt.Errorf("failed to connect: host sent ed25519 key that does not match pinned keys")
}
}
// Check if we're authorized to connect to this key / IP
if intf.incoming && !intf.force && !intf.links.core.peers.isAllowedEncryptionPublicKey(&meta.box) {
intf.links.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, nil
}
// Check if we already have a link to this node
intf.info.box = meta.box
intf.info.sig = meta.sig
intf.links.mutex.Lock()
if oldIntf, isIn := intf.links.links[intf.info]; isIn {
intf.links.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.links.core.log.Debugln("DEBUG: found existing interface for", intf.name)
intf.msgIO.close()
return oldIntf.closed, nil
} else {
intf.closed = make(chan struct{})
intf.links.links[intf.info] = intf
defer func() {
intf.links.mutex.Lock()
delete(intf.links.links, intf.info)
intf.links.mutex.Unlock()
close(intf.closed)
}()
intf.links.core.log.Debugln("DEBUG: registered interface for", intf.name)
}
intf.links.mutex.Unlock()
// Create peer
shared := crypto.GetSharedKey(myLinkPriv, &meta.link)
phony.Block(&intf.links.core.peers, func() {
// FIXME don't use phony.Block, it's bad practice, even if it's safe here
intf.peer = intf.links.core.peers._newPeer(&meta.box, &meta.sig, shared, intf)
})
if intf.peer == nil {
return nil, errors.New("failed to create peer")
}
defer func() {
// More cleanup can go here
intf.Act(nil, func() {
intf.shutdown = true
intf.peer.Act(intf, intf.peer._removeSelf)
})
}()
themAddr := address.AddrForNodeID(crypto.GetNodeID(&intf.info.box))
themAddrString := net.IP(themAddr[:]).String()
themString := fmt.Sprintf("%s@%s", themAddrString, intf.info.remote)
intf.links.core.log.Infof("Connected %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
// Start things
go intf.peer.start()
intf.Act(nil, intf._notifyIdle)
intf.reader.Act(nil, intf.reader._read)
// Wait for the reader to finish
// TODO find a way to do this without keeping live goroutines around
done := make(chan struct{})
defer close(done)
go func() {
select {
case <-intf.links.stopped:
intf.msgIO.close()
case <-done:
}
}()
err = <-intf.reader.err
// TODO don't report an error if it's just a 'use of closed network connection'
if err != nil {
intf.links.core.log.Infof("Disconnected %s: %s, source %s; error: %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local, err)
} else {
intf.links.core.log.Infof("Disconnected %s: %s, source %s",
strings.ToUpper(intf.info.linkType), themString, intf.info.local)
}
return nil, err
}
////////////////////////////////////////////////////////////////////////////////
// link needs to match the linkInterface type needed by the peers
type linkInterface interface {
out([][]byte)
linkOut([]byte)
close()
// These next ones are only used by the API
name() string
local() string
remote() string
interfaceType() string
}
func (intf *link) out(bss [][]byte) {
intf.Act(nil, func() {
// nil to prevent it from blocking if the link is somehow frozen
// this is safe because another packet won't be sent until the link notifies
// the peer that it's ready for one
intf.writer.sendFrom(nil, bss)
})
}
func (intf *link) linkOut(bs []byte) {
intf.Act(nil, func() {
// nil to prevent it from blocking if the link is somehow frozen
// FIXME this is hypothetically not safe, the peer shouldn't be sending
// additional packets until this one finishes, otherwise this could leak
// memory if writing happens slower than link packets are generated...
// that seems unlikely, so it's a lesser evil than deadlocking for now
intf.writer.sendFrom(nil, [][]byte{bs})
})
}
func (intf *link) close() {
intf.Act(nil, func() { intf.msgIO.close() })
}
func (intf *link) name() string {
return intf.lname
}
func (intf *link) local() string {
return intf.info.local
}
func (intf *link) remote() string {
return intf.info.remote
}
func (intf *link) interfaceType() string {
return intf.info.linkType
}
////////////////////////////////////////////////////////////////////////////////
const (
sendTime = 1 * time.Second // How long to wait before deciding a send is blocked
keepAliveTime = 2 * time.Second // How long to wait before sending a keep-alive response if we have no real traffic to send
stallTime = 6 * time.Second // How long to wait for response traffic before deciding the connection has stalled
closeTime = 2 * switch_timeout // How long to wait before closing the link
)
// notify the intf that we're currently sending
func (intf *link) notifySending(size int) {
intf.Act(&intf.writer, func() {
intf.sendTimer = time.AfterFunc(sendTime, intf.notifyBlockedSend)
if intf.keepAliveTimer != nil {
intf.keepAliveTimer.Stop()
intf.keepAliveTimer = nil
}
intf.peer.notifyBlocked(intf)
})
}
// This gets called from a time.AfterFunc, and notifies the switch that we appear
// to have gotten blocked on a write, so the switch should start routing traffic
// through other links, if alternatives exist
func (intf *link) notifyBlockedSend() {
intf.Act(nil, func() {
if intf.sendTimer != nil {
//As far as we know, we're still trying to send, and the timer fired.
intf.sendTimer.Stop()
intf.sendTimer = nil
if !intf.shutdown && intf.writeUnblocked {
intf.writeUnblocked = false
intf.links.core.switchTable.blockPeer(intf, intf.peer.port, true)
}
}
})
}
// notify the intf that we've finished sending, returning the peer to the switch
func (intf *link) notifySent(size int) {
intf.Act(&intf.writer, func() {
if intf.sendTimer != nil {
intf.sendTimer.Stop()
intf.sendTimer = nil
}
if intf.keepAliveTimer != nil {
// TODO? unset this when we start sending, not when we finish...
intf.keepAliveTimer.Stop()
intf.keepAliveTimer = nil
}
intf._notifyIdle()
if size > 0 && intf.stallTimer == nil {
intf.stallTimer = time.AfterFunc(stallTime, intf.notifyStalled)
}
if !intf.shutdown && !intf.writeUnblocked {
intf.writeUnblocked = true
intf.links.core.switchTable.unblockPeer(intf, intf.peer.port, true)
}
})
}
// Notify the peer that we're ready for more traffic
func (intf *link) _notifyIdle() {
intf.peer.Act(intf, intf.peer._handleIdle)
}
// Set the peer as stalled, to prevent them from returning to the switch until a read succeeds
func (intf *link) notifyStalled() {
intf.Act(nil, func() { // Sent from a time.AfterFunc
if intf.stallTimer != nil {
intf.stallTimer.Stop()
intf.stallTimer = nil
if !intf.shutdown && intf.readUnblocked {
intf.readUnblocked = false
intf.links.core.switchTable.blockPeer(intf, intf.peer.port, false)
}
}
})
}
// reset the close timer
func (intf *link) notifyReading() {
intf.Act(&intf.reader, func() {
intf.closeTimer = time.AfterFunc(closeTime, func() { intf.msgIO.close() })
})
}
// wake up the link if it was stalled, and (if size > 0) prepare to send keep-alive traffic
func (intf *link) notifyRead(size int) {
intf.Act(&intf.reader, func() {
intf.closeTimer.Stop()
if intf.stallTimer != nil {
intf.stallTimer.Stop()
intf.stallTimer = nil
}
if size > 0 && intf.keepAliveTimer == nil {
intf.keepAliveTimer = time.AfterFunc(keepAliveTime, intf.notifyDoKeepAlive)
}
if !intf.shutdown && !intf.readUnblocked {
intf.readUnblocked = true
intf.links.core.switchTable.unblockPeer(intf, intf.peer.port, false)
}
})
}
// We need to send keep-alive traffic now
func (intf *link) notifyDoKeepAlive() {
intf.Act(nil, func() { // Sent from a time.AfterFunc
if intf.keepAliveTimer != nil {
intf.keepAliveTimer.Stop()
intf.keepAliveTimer = nil
intf.writer.sendFrom(nil, [][]byte{nil}) // Empty keep-alive traffic
}
})
}
////////////////////////////////////////////////////////////////////////////////
type linkWriter struct {
phony.Inbox
intf *link
worker chan [][]byte
closed bool
}
func (w *linkWriter) sendFrom(from phony.Actor, bss [][]byte) {
w.Act(from, func() {
if w.closed {
return
}
var size int
for _, bs := range bss {
size += len(bs)
}
w.intf.notifySending(size)
w.worker <- bss
w.intf.notifySent(size)
})
}
////////////////////////////////////////////////////////////////////////////////
type linkReader struct {
phony.Inbox
intf *link
err chan error
}
func (r *linkReader) _read() {
r.intf.notifyReading()
msg, err := r.intf.msgIO.readMsg()
r.intf.notifyRead(len(msg))
if len(msg) > 0 {
r.intf.peer.handlePacketFrom(r, msg)
}
if err != nil {
if err != io.EOF {
r.err <- err
}
close(r.err)
return
}
// Now try to read again
r.Act(nil, r._read)
}