cloudflared-mirror/vendor/github.com/lucas-clemente/quic-go/internal/handshake/retry.go

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package handshake
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"fmt"
"sync"
"github.com/lucas-clemente/quic-go/internal/protocol"
)
var (
oldRetryAEAD cipher.AEAD // used for QUIC draft versions up to 34
retryAEAD cipher.AEAD // used for QUIC draft-34
)
func init() {
oldRetryAEAD = initAEAD([16]byte{0xcc, 0xce, 0x18, 0x7e, 0xd0, 0x9a, 0x09, 0xd0, 0x57, 0x28, 0x15, 0x5a, 0x6c, 0xb9, 0x6b, 0xe1})
retryAEAD = initAEAD([16]byte{0xbe, 0x0c, 0x69, 0x0b, 0x9f, 0x66, 0x57, 0x5a, 0x1d, 0x76, 0x6b, 0x54, 0xe3, 0x68, 0xc8, 0x4e})
}
func initAEAD(key [16]byte) cipher.AEAD {
aes, err := aes.NewCipher(key[:])
if err != nil {
panic(err)
}
aead, err := cipher.NewGCM(aes)
if err != nil {
panic(err)
}
return aead
}
var (
retryBuf bytes.Buffer
retryMutex sync.Mutex
oldRetryNonce = [12]byte{0xe5, 0x49, 0x30, 0xf9, 0x7f, 0x21, 0x36, 0xf0, 0x53, 0x0a, 0x8c, 0x1c}
retryNonce = [12]byte{0x46, 0x15, 0x99, 0xd3, 0x5d, 0x63, 0x2b, 0xf2, 0x23, 0x98, 0x25, 0xbb}
)
// GetRetryIntegrityTag calculates the integrity tag on a Retry packet
func GetRetryIntegrityTag(retry []byte, origDestConnID protocol.ConnectionID, version protocol.VersionNumber) *[16]byte {
retryMutex.Lock()
retryBuf.WriteByte(uint8(origDestConnID.Len()))
retryBuf.Write(origDestConnID.Bytes())
retryBuf.Write(retry)
var tag [16]byte
var sealed []byte
if version != protocol.VersionDraft34 && version != protocol.Version1 {
sealed = oldRetryAEAD.Seal(tag[:0], oldRetryNonce[:], nil, retryBuf.Bytes())
} else {
sealed = retryAEAD.Seal(tag[:0], retryNonce[:], nil, retryBuf.Bytes())
}
if len(sealed) != 16 {
panic(fmt.Sprintf("unexpected Retry integrity tag length: %d", len(sealed)))
}
retryBuf.Reset()
retryMutex.Unlock()
return &tag
}