59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
package antireplay
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import (
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"sync"
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"time"
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cuckoo "github.com/seiflotfy/cuckoofilter"
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)
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const replayFilterCapacity = 100000
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// ReplayFilter checks for replay attacks.
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type ReplayFilter struct {
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lock sync.Mutex
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poolA *cuckoo.Filter
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poolB *cuckoo.Filter
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poolSwap bool
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lastSwap int64
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interval int64
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}
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// NewReplayFilter create a new filter with specifying the expiration time interval in seconds.
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func NewReplayFilter(interval int64) *ReplayFilter {
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filter := &ReplayFilter{}
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filter.interval = interval
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return filter
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}
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// Interval in second for expiration time for duplicate records.
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func (filter *ReplayFilter) Interval() int64 {
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return filter.interval
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}
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// Check determines if there are duplicate records.
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func (filter *ReplayFilter) Check(sum []byte) bool {
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filter.lock.Lock()
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defer filter.lock.Unlock()
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now := time.Now().Unix()
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if filter.lastSwap == 0 {
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filter.lastSwap = now
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filter.poolA = cuckoo.NewFilter(replayFilterCapacity)
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filter.poolB = cuckoo.NewFilter(replayFilterCapacity)
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}
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elapsed := now - filter.lastSwap
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if elapsed >= filter.Interval() {
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if filter.poolSwap {
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filter.poolA.Reset()
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} else {
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filter.poolB.Reset()
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}
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filter.poolSwap = !filter.poolSwap
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filter.lastSwap = now
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}
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return filter.poolA.InsertUnique(sum) && filter.poolB.InsertUnique(sum)
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}
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