cwinfo/yggdrasil-go
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Try to tidy up a bit, move checks for if we are already calling/connected

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Something I noticed when working on reconfigure support for the "Listen"
option is that we have some rather huge weaknesses in our multicasting
design. Right now if we change our Listen address, it's not really
possible for remote nodes to know whether they are still connected to
us, so they start connecting in response to our changed beacons. They
can't know that they already know about us until *after* the handshake
but this registers in the local client log as repeated Connect/Disconnects
even though the existing peerings never actually drop.
This commit is contained in:
Neil Alexander 2018-12-30 21:11:16 +00:00
parent 80c9a1bc12
commit cd86c33850
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
1 changed files with 46 additions and 28 deletions
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74
src/yggdrasil/tcp.go
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@ -53,8 +53,8 @@ type tcpInterface struct {
type tcpInfo struct {
box crypto.BoxPubKey
sig crypto.SigPubKey
localAddr string
remoteAddr string
remotePort string
}
// Wrapper function to set additional options for specific connection types.
@ -150,6 +150,22 @@ func (iface *tcpInterface) listener() {
}
}
// Checks if we already have a connection to this node
func (iface *tcpInterface) isAlreadyConnected(info tcpInfo) bool {
iface.mutex.Lock()
defer iface.mutex.Unlock()
_, isIn := iface.conns[info]
return isIn
}
// Checks if we already are calling this address
func (iface *tcpInterface) isAlreadyCalling(saddr string) bool {
iface.mutex.Lock()
defer iface.mutex.Unlock()
_, isIn := iface.calls[saddr]
return isIn
}
// Checks if a connection already exists.
// If not, it adds it to the list of active outgoing calls (to block future attempts) and dials the address.
// If the dial is successful, it launches the handler.
@ -161,25 +177,18 @@ func (iface *tcpInterface) call(saddr string, socksaddr *string, sintf string) {
if sintf != "" {
callname = fmt.Sprintf("%s/%s", saddr, sintf)
}
quit := false
iface.mutex.Lock()
if _, isIn := iface.calls[callname]; isIn {
quit = true
} else {
iface.calls[callname] = struct{}{}
defer func() {
// Block new calls for a little while, to mitigate livelock scenarios
time.Sleep(default_tcp_timeout)
time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond)
iface.mutex.Lock()
delete(iface.calls, callname)
iface.mutex.Unlock()
}()
}
iface.mutex.Unlock()
if quit {
if iface.isAlreadyCalling(saddr) {
return
}
iface.calls[callname] = struct{}{}
defer func() {
// Block new calls for a little while, to mitigate livelock scenarios
time.Sleep(default_tcp_timeout)
time.Sleep(time.Duration(rand.Intn(1000)) * time.Millisecond)
iface.mutex.Lock()
delete(iface.calls, callname)
iface.mutex.Unlock()
}()
var conn net.Conn
var err error
if socksaddr != nil {
@ -284,9 +293,19 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
// TODO? Block forever to prevent future connection attempts? suppress future messages about the same node?
return
}
remoteAddr, _, e1 := net.SplitHostPort(sock.RemoteAddr().String())
localAddr, _, e2 := net.SplitHostPort(sock.LocalAddr().String())
if e1 != nil || e2 != nil {
return
}
info := tcpInfo{ // used as a map key, so don't include ephemeral link key
box: meta.box,
sig: meta.sig,
box: meta.box,
sig: meta.sig,
localAddr: localAddr,
remoteAddr: remoteAddr,
}
if iface.isAlreadyConnected(info) {
return
}
// Quit the parent call if this is a connection to ourself
equiv := func(k1, k2 []byte) bool {
@ -297,14 +316,14 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
}
return true
}
if equiv(info.box[:], iface.core.boxPub[:]) {
if equiv(meta.box[:], iface.core.boxPub[:]) {
return
}
if equiv(info.sig[:], iface.core.sigPub[:]) {
if equiv(meta.sig[:], iface.core.sigPub[:]) {
return
}
// Check if we're authorized to connect to this key / IP
if incoming && !iface.core.peers.isAllowedEncryptionPublicKey(&info.box) {
if incoming && !iface.core.peers.isAllowedEncryptionPublicKey(&meta.box) {
// Allow unauthorized peers if they're link-local
raddrStr, _, _ := net.SplitHostPort(sock.RemoteAddr().String())
raddr := net.ParseIP(raddrStr)
@ -313,14 +332,13 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
}
}
// Check if we already have a connection to this node, close and block if yes
info.remoteAddr, info.remotePort, _ = net.SplitHostPort(sock.RemoteAddr().String())
iface.mutex.Lock()
if blockChan, isIn := iface.conns[info]; isIn {
/*if blockChan, isIn := iface.conns[info]; isIn {
iface.mutex.Unlock()
sock.Close()
<-blockChan
return
}
}*/
blockChan := make(chan struct{})
iface.conns[info] = blockChan
iface.mutex.Unlock()
@ -332,7 +350,7 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
}()
// Note that multiple connections to the same node are allowed
// E.g. over different interfaces
p := iface.core.peers.newPeer(&info.box, &info.sig, crypto.GetSharedKey(myLinkPriv, &meta.link), sock.RemoteAddr().String())
p := iface.core.peers.newPeer(&meta.box, &meta.sig, crypto.GetSharedKey(myLinkPriv, &meta.link), sock.RemoteAddr().String())
p.linkOut = make(chan []byte, 1)
in := func(bs []byte) {
p.handlePacket(bs)
@ -394,7 +412,7 @@ func (iface *tcpInterface) handler(sock net.Conn, incoming bool) {
}()
us, _, _ := net.SplitHostPort(sock.LocalAddr().String())
them, _, _ := net.SplitHostPort(sock.RemoteAddr().String())
themNodeID := crypto.GetNodeID(&info.box)
themNodeID := crypto.GetNodeID(&meta.box)
themAddr := address.AddrForNodeID(themNodeID)
themAddrString := net.IP(themAddr[:]).String()
themString := fmt.Sprintf("%s@%s", themAddrString, them)