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