Chore: split component to transport

transport/vmess/header.go

@@ -0,0 +1,103 @@
+package vmess
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/binary"
+	"hash"
+	"hash/crc32"
+	"time"
+)
+
+const (
+	kdfSaltConstAuthIDEncryptionKey             = "AES Auth ID Encryption"
+	kdfSaltConstAEADRespHeaderLenKey            = "AEAD Resp Header Len Key"
+	kdfSaltConstAEADRespHeaderLenIV             = "AEAD Resp Header Len IV"
+	kdfSaltConstAEADRespHeaderPayloadKey        = "AEAD Resp Header Key"
+	kdfSaltConstAEADRespHeaderPayloadIV         = "AEAD Resp Header IV"
+	kdfSaltConstVMessAEADKDF                    = "VMess AEAD KDF"
+	kdfSaltConstVMessHeaderPayloadAEADKey       = "VMess Header AEAD Key"
+	kdfSaltConstVMessHeaderPayloadAEADIV        = "VMess Header AEAD Nonce"
+	kdfSaltConstVMessHeaderPayloadLengthAEADKey = "VMess Header AEAD Key_Length"
+	kdfSaltConstVMessHeaderPayloadLengthAEADIV  = "VMess Header AEAD Nonce_Length"
+)
+
+func kdf(key []byte, path ...string) []byte {
+	hmacCreator := &hMacCreator{value: []byte(kdfSaltConstVMessAEADKDF)}
+	for _, v := range path {
+		hmacCreator = &hMacCreator{value: []byte(v), parent: hmacCreator}
+	}
+	hmacf := hmacCreator.Create()
+	hmacf.Write(key)
+	return hmacf.Sum(nil)
+}
+
+type hMacCreator struct {
+	parent *hMacCreator
+	value  []byte
+}
+
+func (h *hMacCreator) Create() hash.Hash {
+	if h.parent == nil {
+		return hmac.New(sha256.New, h.value)
+	}
+	return hmac.New(h.parent.Create, h.value)
+}
+
+func createAuthID(cmdKey []byte, time int64) [16]byte {
+	buf := &bytes.Buffer{}
+	binary.Write(buf, binary.BigEndian, time)
+
+	random := make([]byte, 4)
+	rand.Read(random)
+	buf.Write(random)
+	zero := crc32.ChecksumIEEE(buf.Bytes())
+	binary.Write(buf, binary.BigEndian, zero)
+
+	aesBlock, _ := aes.NewCipher(kdf(cmdKey[:], kdfSaltConstAuthIDEncryptionKey)[:16])
+	var result [16]byte
+	aesBlock.Encrypt(result[:], buf.Bytes())
+	return result
+}
+
+func sealVMessAEADHeader(key [16]byte, data []byte, t time.Time) []byte {
+	generatedAuthID := createAuthID(key[:], t.Unix())
+	connectionNonce := make([]byte, 8)
+	rand.Read(connectionNonce)
+
+	aeadPayloadLengthSerializedByte := make([]byte, 2)
+	binary.BigEndian.PutUint16(aeadPayloadLengthSerializedByte, uint16(len(data)))
+
+	var payloadHeaderLengthAEADEncrypted []byte
+
+	{
+		payloadHeaderLengthAEADKey := kdf(key[:], kdfSaltConstVMessHeaderPayloadLengthAEADKey, string(generatedAuthID[:]), string(connectionNonce))[:16]
+		payloadHeaderLengthAEADNonce := kdf(key[:], kdfSaltConstVMessHeaderPayloadLengthAEADIV, string(generatedAuthID[:]), string(connectionNonce))[:12]
+		payloadHeaderLengthAEADAESBlock, _ := aes.NewCipher(payloadHeaderLengthAEADKey)
+		payloadHeaderAEAD, _ := cipher.NewGCM(payloadHeaderLengthAEADAESBlock)
+		payloadHeaderLengthAEADEncrypted = payloadHeaderAEAD.Seal(nil, payloadHeaderLengthAEADNonce, aeadPayloadLengthSerializedByte, generatedAuthID[:])
+	}
+
+	var payloadHeaderAEADEncrypted []byte
+
+	{
+		payloadHeaderAEADKey := kdf(key[:], kdfSaltConstVMessHeaderPayloadAEADKey, string(generatedAuthID[:]), string(connectionNonce))[:16]
+		payloadHeaderAEADNonce := kdf(key[:], kdfSaltConstVMessHeaderPayloadAEADIV, string(generatedAuthID[:]), string(connectionNonce))[:12]
+		payloadHeaderAEADAESBlock, _ := aes.NewCipher(payloadHeaderAEADKey)
+		payloadHeaderAEAD, _ := cipher.NewGCM(payloadHeaderAEADAESBlock)
+		payloadHeaderAEADEncrypted = payloadHeaderAEAD.Seal(nil, payloadHeaderAEADNonce, data, generatedAuthID[:])
+	}
+
+	var outputBuffer = &bytes.Buffer{}
+
+	outputBuffer.Write(generatedAuthID[:])
+	outputBuffer.Write(payloadHeaderLengthAEADEncrypted)
+	outputBuffer.Write(connectionNonce)
+	outputBuffer.Write(payloadHeaderAEADEncrypted)
+
+	return outputBuffer.Bytes()
+}