60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
|
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
|
||
|
|
}
|