path: root/p2p/metrics.go

// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

// Contains the meters and timers used by the networking layer.

package p2p

import (
    "fmt"
    "net"
    "sync"
    "sync/atomic"
    "time"

    "github.com/dexon-foundation/dexon/p2p/enode"

    "github.com/dexon-foundation/dexon/event"
    "github.com/dexon-foundation/dexon/log"
    "github.com/dexon-foundation/dexon/metrics"
)

const (
    MetricsInboundConnects  = "p2p/InboundConnects"  // Name for the registered inbound connects meter
    MetricsInboundTraffic   = "p2p/InboundTraffic"   // Name for the registered inbound traffic meter
    MetricsOutboundConnects = "p2p/OutboundConnects" // Name for the registered outbound connects meter
    MetricsOutboundTraffic  = "p2p/OutboundTraffic"  // Name for the registered outbound traffic meter

    MeteredPeerLimit = 1024 // This amount of peers are individually metered
)

var (
    ingressConnectMeter = metrics.NewRegisteredMeter(MetricsInboundConnects, nil)  // Meter counting the ingress connections
    ingressTrafficMeter = metrics.NewRegisteredMeter(MetricsInboundTraffic, nil)   // Meter metering the cumulative ingress traffic
    egressConnectMeter  = metrics.NewRegisteredMeter(MetricsOutboundConnects, nil) // Meter counting the egress connections
    egressTrafficMeter  = metrics.NewRegisteredMeter(MetricsOutboundTraffic, nil)  // Meter metering the cumulative egress traffic

    PeerIngressRegistry = metrics.NewPrefixedChildRegistry(metrics.EphemeralRegistry, MetricsInboundTraffic+"/")  // Registry containing the peer ingress
    PeerEgressRegistry  = metrics.NewPrefixedChildRegistry(metrics.EphemeralRegistry, MetricsOutboundTraffic+"/") // Registry containing the peer egress

    meteredPeerFeed  event.Feed // Event feed for peer metrics
    meteredPeerCount int32      // Actually stored peer connection count
)

// MeteredPeerEventType is the type of peer events emitted by a metered connection.
type MeteredPeerEventType int

const (
    // PeerConnected is the type of event emitted when a peer successfully
    // made the handshake.
    PeerConnected MeteredPeerEventType = iota

    // PeerDisconnected is the type of event emitted when a peer disconnects.
    PeerDisconnected

    // PeerHandshakeFailed is the type of event emitted when a peer fails to
    // make the handshake or disconnects before the handshake.
    PeerHandshakeFailed
)

// MeteredPeerEvent is an event emitted when peers connect or disconnect.
type MeteredPeerEvent struct {
    Type    MeteredPeerEventType // Type of peer event
    IP      net.IP               // IP address of the peer
    ID      enode.ID             // NodeID of the peer
    Elapsed time.Duration        // Time elapsed between the connection and the handshake/disconnection
    Ingress uint64               // Ingress count at the moment of the event
    Egress  uint64               // Egress count at the moment of the event
}

// SubscribeMeteredPeerEvent registers a subscription for peer life-cycle events
// if metrics collection is enabled.
func SubscribeMeteredPeerEvent(ch chan<- MeteredPeerEvent) event.Subscription {
    return meteredPeerFeed.Subscribe(ch)
}

// meteredConn is a wrapper around a net.Conn that meters both the
// inbound and outbound network traffic.
type meteredConn struct {
    net.Conn // Network connection to wrap with metering

    connected time.Time // Connection time of the peer
    ip        net.IP    // IP address of the peer
    id        enode.ID  // NodeID of the peer

    // trafficMetered denotes if the peer is registered in the traffic registries.
    // Its value is true if the metered peer count doesn't reach the limit in the
    // moment of the peer's connection.
    trafficMetered bool
    ingressMeter   metrics.Meter // Meter for the read bytes of the peer
    egressMeter    metrics.Meter // Meter for the written bytes of the peer

    lock sync.RWMutex // Lock protecting the metered connection's internals
}

// newMeteredConn creates a new metered connection, bumps the ingress or egress
// connection meter and also increases the metered peer count. If the metrics
// system is disabled or the IP address is unspecified, this function returns
// the original object.
func newMeteredConn(conn net.Conn, ingress bool, ip net.IP) net.Conn {
    // Short circuit if metrics are disabled
    if !metrics.Enabled {
        return conn
    }
    if ip.IsUnspecified() {
        log.Warn("Peer IP is unspecified")
        return conn
    }
    // Bump the connection counters and wrap the connection
    if ingress {
        ingressConnectMeter.Mark(1)
    } else {
        egressConnectMeter.Mark(1)
    }
    return &meteredConn{
        Conn:      conn,
        ip:        ip,
        connected: time.Now(),
    }
}

// Read delegates a network read to the underlying connection, bumping the common
// and the peer ingress traffic meters along the way.
func (c *meteredConn) Read(b []byte) (n int, err error) {
    n, err = c.Conn.Read(b)
    ingressTrafficMeter.Mark(int64(n))
    c.lock.RLock()
    if c.trafficMetered {
        c.ingressMeter.Mark(int64(n))
    }
    c.lock.RUnlock()
    return n, err
}

// Write delegates a network write to the underlying connection, bumping the common
// and the peer egress traffic meters along the way.
func (c *meteredConn) Write(b []byte) (n int, err error) {
    n, err = c.Conn.Write(b)
    egressTrafficMeter.Mark(int64(n))
    c.lock.RLock()
    if c.trafficMetered {
        c.egressMeter.Mark(int64(n))
    }
    c.lock.RUnlock()
    return n, err
}

// handshakeDone is called when a peer handshake is done. Registers the peer to
// the ingress and the egress traffic registries using the peer's IP and node ID,
// also emits connect event.
func (c *meteredConn) handshakeDone(id enode.ID) {
    if atomic.AddInt32(&meteredPeerCount, 1) >= MeteredPeerLimit {
        // Don't register the peer in the traffic registries.
        atomic.AddInt32(&meteredPeerCount, -1)
        c.lock.Lock()
        c.id, c.trafficMetered = id, false
        c.lock.Unlock()
        log.Warn("Metered peer count reached the limit")
    } else {
        key := fmt.Sprintf("%s/%s", c.ip, id.String())
        c.lock.Lock()
        c.id, c.trafficMetered = id, true
        c.ingressMeter = metrics.NewRegisteredMeter(key, PeerIngressRegistry)
        c.egressMeter = metrics.NewRegisteredMeter(key, PeerEgressRegistry)
        c.lock.Unlock()
    }
    meteredPeerFeed.Send(MeteredPeerEvent{
        Type:    PeerConnected,
        IP:      c.ip,
        ID:      id,
        Elapsed: time.Since(c.connected),
    })
}

// Close delegates a close operation to the underlying connection, unregisters
// the peer from the traffic registries and emits close event.
func (c *meteredConn) Close() error {
    err := c.Conn.Close()
    c.lock.RLock()
    if c.id == (enode.ID{}) {
        // If the peer disconnects before the handshake.
        c.lock.RUnlock()
        meteredPeerFeed.Send(MeteredPeerEvent{
            Type:    PeerHandshakeFailed,
            IP:      c.ip,
            Elapsed: time.Since(c.connected),
        })
        return err
    }
    id := c.id
    if !c.trafficMetered {
        // If the peer isn't registered in the traffic registries.
        c.lock.RUnlock()
        meteredPeerFeed.Send(MeteredPeerEvent{
            Type: PeerDisconnected,
            IP:   c.ip,
            ID:   id,
        })
        return err
    }
    ingress, egress := uint64(c.ingressMeter.Count()), uint64(c.egressMeter.Count())
    c.lock.RUnlock()

    // Decrement the metered peer count
    atomic.AddInt32(&meteredPeerCount, -1)

    // Unregister the peer from the traffic registries
    key := fmt.Sprintf("%s/%s", c.ip, id)
    PeerIngressRegistry.Unregister(key)
    PeerEgressRegistry.Unregister(key)

    meteredPeerFeed.Send(MeteredPeerEvent{
        Type:    PeerDisconnected,
        IP:      c.ip,
        ID:      id,
        Ingress: ingress,
        Egress:  egress,
    })
    return err
}