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 { 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 }