Rework some things into packages (#489)

firewall/cache.go

@@ -0,0 +1,59 @@
+package firewall
+
+import (
+	"sync/atomic"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+// ConntrackCache is used as a local routine cache to know if a given flow
+// has been seen in the conntrack table.
+type ConntrackCache map[Packet]struct{}
+
+type ConntrackCacheTicker struct {
+	cacheV    uint64
+	cacheTick uint64
+
+	cache ConntrackCache
+}
+
+func NewConntrackCacheTicker(d time.Duration) *ConntrackCacheTicker {
+	if d == 0 {
+		return nil
+	}
+
+	c := &ConntrackCacheTicker{
+		cache: ConntrackCache{},
+	}
+
+	go c.tick(d)
+
+	return c
+}
+
+func (c *ConntrackCacheTicker) tick(d time.Duration) {
+	for {
+		time.Sleep(d)
+		atomic.AddUint64(&c.cacheTick, 1)
+	}
+}
+
+// Get checks if the cache ticker has moved to the next version before returning
+// the map. If it has moved, we reset the map.
+func (c *ConntrackCacheTicker) Get(l *logrus.Logger) ConntrackCache {
+	if c == nil {
+		return nil
+	}
+	if tick := atomic.LoadUint64(&c.cacheTick); tick != c.cacheV {
+		c.cacheV = tick
+		if ll := len(c.cache); ll > 0 {
+			if l.Level == logrus.DebugLevel {
+				l.WithField("len", ll).Debug("resetting conntrack cache")
+			}
+			c.cache = make(ConntrackCache, ll)
+		}
+	}
+
+	return c.cache
+}

firewall/packet.go

@@ -0,0 +1,62 @@
+package firewall
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/slackhq/nebula/iputil"
+)
+
+type m map[string]interface{}
+
+const (
+	ProtoAny  = 0 // When we want to handle HOPOPT (0) we can change this, if ever
+	ProtoTCP  = 6
+	ProtoUDP  = 17
+	ProtoICMP = 1
+
+	PortAny      = 0  // Special value for matching `port: any`
+	PortFragment = -1 // Special value for matching `port: fragment`
+)
+
+type Packet struct {
+	LocalIP    iputil.VpnIp
+	RemoteIP   iputil.VpnIp
+	LocalPort  uint16
+	RemotePort uint16
+	Protocol   uint8
+	Fragment   bool
+}
+
+func (fp *Packet) Copy() *Packet {
+	return &Packet{
+		LocalIP:    fp.LocalIP,
+		RemoteIP:   fp.RemoteIP,
+		LocalPort:  fp.LocalPort,
+		RemotePort: fp.RemotePort,
+		Protocol:   fp.Protocol,
+		Fragment:   fp.Fragment,
+	}
+}
+
+func (fp Packet) MarshalJSON() ([]byte, error) {
+	var proto string
+	switch fp.Protocol {
+	case ProtoTCP:
+		proto = "tcp"
+	case ProtoICMP:
+		proto = "icmp"
+	case ProtoUDP:
+		proto = "udp"
+	default:
+		proto = fmt.Sprintf("unknown %v", fp.Protocol)
+	}
+	return json.Marshal(m{
+		"LocalIP":    fp.LocalIP.String(),
+		"RemoteIP":   fp.RemoteIP.String(),
+		"LocalPort":  fp.LocalPort,
+		"RemotePort": fp.RemotePort,
+		"Protocol":   proto,
+		"Fragment":   fp.Fragment,
+	})
+}