80 lines
1.5 KiB
Go
80 lines
1.5 KiB
Go
package dht
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import (
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"bytes"
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"crypto/rand"
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"crypto/sha256"
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"net"
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"strconv"
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"sync"
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"time"
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"github.com/lbryio/lbry.go/stopOnce"
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)
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type tokenManager struct {
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secret []byte
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prevSecret []byte
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lock *sync.RWMutex
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wg *sync.WaitGroup
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done *stopOnce.Stopper
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}
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func (tm *tokenManager) Start(interval time.Duration) {
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tm.secret = make([]byte, 64)
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tm.prevSecret = make([]byte, 64)
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tm.lock = &sync.RWMutex{}
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tm.wg = &sync.WaitGroup{}
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tm.done = stopOnce.New()
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tm.rotateSecret()
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tm.wg.Add(1)
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go func() {
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defer tm.wg.Done()
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tick := time.NewTicker(interval)
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for {
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select {
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case <-tick.C:
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tm.rotateSecret()
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case <-tm.done.Ch():
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return
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}
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}
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}()
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}
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func (tm *tokenManager) Stop() {
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tm.done.Stop()
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tm.wg.Wait()
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}
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func (tm *tokenManager) Get(nodeID Bitmap, addr *net.UDPAddr) string {
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return genToken(tm.secret, nodeID, addr)
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}
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func (tm *tokenManager) Verify(token string, nodeID Bitmap, addr *net.UDPAddr) bool {
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return token == genToken(tm.secret, nodeID, addr) || token == genToken(tm.prevSecret, nodeID, addr)
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}
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func genToken(secret []byte, nodeID Bitmap, addr *net.UDPAddr) string {
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buf := bytes.Buffer{}
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buf.Write(nodeID[:])
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buf.Write(addr.IP)
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buf.WriteString(strconv.Itoa(addr.Port))
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buf.Write(secret)
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t := sha256.Sum256(buf.Bytes())
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return string(t[:])
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}
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func (tm *tokenManager) rotateSecret() {
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tm.lock.Lock()
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defer tm.lock.Unlock()
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copy(tm.prevSecret, tm.secret)
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_, err := rand.Read(tm.secret)
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if err != nil {
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panic(err)
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}
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}
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