Zef HemelandGitHub
a524c64884
* Replaces old Deno server with a Go implementation * Restructured the code base accordingly
70 lines
1.6 KiB
Go
70 lines
1.6 KiB
Go
package server
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import (
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"math"
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"sync"
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"time"
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)
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// LockoutTimer implements a simple rate limiter to prevent brute force attacks
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type LockoutTimer struct {
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mutex sync.Mutex
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bucketTime int64
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bucketCount int
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bucketSize int64 // duration in milliseconds
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limit int
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disabled bool
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}
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// NewLockoutTimer creates a new lockout timer
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// countPeriodMs: time window in milliseconds
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// limit: maximum attempts allowed in the time window
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func NewLockoutTimer(countPeriodMs int, limit int) *LockoutTimer {
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disabled := math.IsNaN(float64(countPeriodMs)) || math.IsNaN(float64(limit)) ||
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countPeriodMs < 1 || limit < 1
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return &LockoutTimer{
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bucketSize: int64(countPeriodMs),
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limit: limit,
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disabled: disabled,
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}
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}
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// updateBucketTime updates the current bucket time and resets count if needed
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func (lt *LockoutTimer) updateBucketTime() {
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currentBucketTime := time.Now().UnixMilli() / lt.bucketSize
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if lt.bucketTime == currentBucketTime {
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return
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}
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// the bucket is too old - empty it
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lt.bucketTime = currentBucketTime
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lt.bucketCount = 0
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}
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// IsLocked checks if the timer is currently locked due to too many attempts
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func (lt *LockoutTimer) IsLocked() bool {
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if lt.disabled {
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return false
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}
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lt.mutex.Lock()
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defer lt.mutex.Unlock()
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lt.updateBucketTime()
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return lt.bucketCount >= lt.limit
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}
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// AddCount increments the attempt counter
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// IsLocked() should be called first to keep bucketTime current
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func (lt *LockoutTimer) AddCount() {
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if lt.disabled {
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return
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}
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lt.mutex.Lock()
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defer lt.mutex.Unlock()
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// updateBucketTime should have been called by IsLocked first
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lt.bucketCount++
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}
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