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Proper multiqueue support for tun devices (#382)

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This change is for Linux only.

Previously, when running with multiple tun.routines, we would only have one file descriptor. This change instead sets IFF_MULTI_QUEUE and opens a file descriptor for each routine. This allows us to process with multiple threads while preventing out of order packet reception issues.

To attempt to distribute the flows across the queues, we try to write to the tun/UDP queue that corresponds with the one we read from. So if we read a packet from tun queue "2", we will write the outgoing encrypted packet to UDP queue "2". Because of the nature of how multi queue works with flows, a given host tunnel will be sticky to a given routine (so if you try to performance benchmark by only using one tunnel between two hosts, you are only going to be using a max of one thread for each direction).

Because this system works much better when we can correlate flows between the tun and udp routines, we are deprecating the undocumented "tun.routines" and "listen.routines" parameters and introducing a new "routines" parameter that sets the value for both. If you use the old undocumented parameters, the max of the values will be used and a warning logged.

Co-authored-by: Nate Brown <nbrown.us@gmail.com>
This commit is contained in:
Wade Simmons
2021-02-25 15:01:14 -05:00
committed by GitHub
parent 2bce222550
commit 27d9a67dda
14 changed files with 175 additions and 73 deletions
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74
main.go
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@ -93,6 +93,30 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
// tun config, listeners, anything modifying the computer should be below
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
var routines int
// If `routines` is set, use that and ignore the specific values
if routines = config.GetInt("routines", 0); routines != 0 {
if routines < 1 {
routines = 1
}
if routines > 1 {
l.WithField("routines", routines).Info("Using multiple routines")
}
} else {
// deprecated and undocumented
tunQueues := config.GetInt("tun.routines", 1)
udpQueues := config.GetInt("listen.routines", 1)
if tunQueues > udpQueues {
routines = tunQueues
} else {
routines = udpQueues
}
if routines != 1 {
l.WithField("routines", routines).Warn("Setting tun.routines and listen.routines is deprecated. Use `routines` instead")
}
}
var tun Inside
if !configTest {
config.CatchHUP()
@ -117,6 +141,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
routes,
unsafeRoutes,
config.GetInt("tun.tx_queue", 500),
routines > 1,
)
}
@ -126,15 +151,27 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
}
// set up our UDP listener
udpQueues := config.GetInt("listen.routines", 1)
var udpServer *udpConn
udpConns := make([]*udpConn, routines)
port := config.GetInt("listen.port", 0)
if !configTest {
udpServer, err = NewListener(config.GetString("listen.host", "0.0.0.0"), config.GetInt("listen.port", 0), udpQueues > 1)
if err != nil {
return nil, NewContextualError("Failed to open udp listener", nil, err)
for i := 0; i < routines; i++ {
udpServer, err := NewListener(config.GetString("listen.host", "0.0.0.0"), port, routines > 1)
if err != nil {
return nil, NewContextualError("Failed to open udp listener", m{"queue": i}, err)
}
udpServer.reloadConfig(config)
udpConns[i] = udpServer
// If port is dynamic, discover it
if port == 0 {
uPort, err := udpServer.LocalAddr()
if err != nil {
return nil, NewContextualError("Failed to get listening port", nil, err)
}
port = int(uPort.Port)
}
}
udpServer.reloadConfig(config)
}
// Set up my internal host map
@ -190,17 +227,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
punchy := NewPunchyFromConfig(config)
if punchy.Punch && !configTest {
l.Info("UDP hole punching enabled")
go hostMap.Punchy(udpServer)
}
port := config.GetInt("listen.port", 0)
// If port is dynamic, discover it
if port == 0 && !configTest {
uPort, err := udpServer.LocalAddr()
if err != nil {
return nil, NewContextualError("Failed to get listening port", nil, err)
}
port = int(uPort.Port)
go hostMap.Punchy(udpConns[0])
}
amLighthouse := config.GetBool("lighthouse.am_lighthouse", false)
@ -230,7 +257,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
//TODO: change to a duration
config.GetInt("lighthouse.interval", 10),
port,
udpServer,
udpConns[0],
punchy.Respond,
punchy.Delay,
config.GetBool("stats.lighthouse_metrics", false),
@ -304,7 +331,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
messageMetrics: messageMetrics,
}
handshakeManager := NewHandshakeManager(tunCidr, preferredRanges, hostMap, lightHouse, udpServer, handshakeConfig)
handshakeManager := NewHandshakeManager(tunCidr, preferredRanges, hostMap, lightHouse, udpConns[0], handshakeConfig)
lightHouse.handshakeTrigger = handshakeManager.trigger
//TODO: These will be reused for psk
@ -317,7 +344,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
ifConfig := &InterfaceConfig{
HostMap: hostMap,
Inside: tun,
Outside: udpServer,
Outside: udpConns[0],
certState: cs,
Cipher: config.GetString("cipher", "aes"),
Firewall: fw,
@ -329,8 +356,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
DropLocalBroadcast: config.GetBool("tun.drop_local_broadcast", false),
DropMulticast: config.GetBool("tun.drop_multicast", false),
UDPBatchSize: config.GetInt("listen.batch", 64),
udpQueues: udpQueues,
tunQueues: config.GetInt("tun.routines", 1),
routines: routines,
MessageMetrics: messageMetrics,
version: buildVersion,
}
@ -351,6 +377,10 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
return nil, fmt.Errorf("failed to initialize interface: %s", err)
}
// TODO: Better way to attach these, probably want a new interface in InterfaceConfig
// I don't want to make this initial commit too far-reaching though
ifce.writers = udpConns
ifce.RegisterConfigChangeCallbacks(config)
go handshakeManager.Run(ifce)