40 lines
704 B
Go
40 lines
704 B
Go
package main
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import (
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"errors"
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"golang.org/x/crypto/blake2s"
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)
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func CalculateCookie(peer *Peer, msg []byte) {
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size := len(msg)
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if size < blake2s.Size128*2 {
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panic(errors.New("bug: message too short"))
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}
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startMac1 := size - (blake2s.Size128 * 2)
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startMac2 := size - blake2s.Size128
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mac1 := msg[startMac1 : startMac1+blake2s.Size128]
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mac2 := msg[startMac2 : startMac2+blake2s.Size128]
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peer.mutex.RLock()
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defer peer.mutex.RUnlock()
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// set mac1
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func() {
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mac, _ := blake2s.New128(peer.macKey[:])
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mac.Write(msg[:startMac1])
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mac.Sum(mac1[:0])
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}()
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// set mac2
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if peer.cookie != nil {
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mac, _ := blake2s.New128(peer.cookie)
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mac.Write(msg[:startMac2])
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mac.Sum(mac2[:0])
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}
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}
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