Communicate transport parameters via encrypted payload

quic/openarray.nim

@@ -6,3 +6,6 @@ proc `[]=`*[T,U,V](
   doAssert replacement.len == slice.len
   for i in 0..<replacement.len:
     target[slice.a + i] = replacement[i]
+
+template toOpenArray*[T](a: ptr T, length: uint): openArray[T] =
+  toOpenArray(cast[ptr UncheckedArray[T]](a), 0, length.int-1)

tests/quic/helpers/client.nim

@@ -1,3 +1,4 @@
+import quic/openarray
 import ngtcp2
 import ids
 import encrypt
@@ -5,21 +6,18 @@ import decrypt
 import hp
 import keys
 import settings
+import params
+import crypto
 
 let zeroKey = Key()
-var cryptoData: array[4096, uint8]
 var randomId: ngtcp2_cid
 
 proc clientInitial(connection: ptr ngtcp2_conn, user_data: pointer): cint {.cdecl.} =
   connection.install0RttKey(zeroKey)
-
-  assert 0 == ngtcp2_conn_submit_crypto_data(
-    connection, NGTCP2_CRYPTO_LEVEL_INITIAL, addr cryptoData[0], sizeof(cryptoData).uint
-  )
+  connection.submitCryptoData()
 
 proc receiveCryptoData(connection: ptr ngtcp2_conn, level: ngtcp2_crypto_level, offset: uint64, data: ptr uint8, datalen: uint, userData: pointer): cint {.cdecl.} =
-  var params = defaultSettings().transport_params
-  params.initial_scid = connection.ngtcp2_conn_get_dcid()[]
+  var params = decodeTransportParameters(toOpenArray(data, datalen))
   params.original_dcid = randomId
   assert 0 == ngtcp2_conn_set_remote_transport_params(connection, addr params)
 

tests/quic/helpers/crypto.nim

@@ -0,0 +1,11 @@
+import ngtcp2
+import params
+
+proc submitCryptoData*(connection: ptr ngtcp2_conn) =
+  var cryptoData = connection.encodeTransportParameters()
+  assert 0 == ngtcp2_conn_submit_crypto_data(
+    connection,
+    NGTCP2_CRYPTO_LEVEL_INITIAL,
+    addr cryptoData[0],
+    cryptoData.len.uint
+  )

tests/quic/helpers/params.nim

@@ -0,0 +1,22 @@
+import ngtcp2
+
+proc encodeTransportParameters*(connection: ptr ngtcp2_conn): seq[byte] =
+  var buffer: array[4096, byte]
+  var params: ngtcp2_transport_params
+  connection.ngtcp2_conn_get_local_transport_params(addr params)
+  let length = ngtcp2_encode_transport_params(
+    addr buffer[0],
+    buffer.len.uint,
+    NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO,
+    addr params
+  )
+  buffer[0..<length]
+
+proc decodeTransportParameters*(bytes: openArray[byte]): ngtcp2_transport_params =
+  assert 0 == ngtcp2_decode_transport_params(
+    addr result,
+    NGTCP2_TRANSPORT_PARAMS_TYPE_CLIENT_HELLO,
+    unsafeAddr bytes[0],
+    bytes.len.uint
+  )
+

tests/quic/helpers/server.nim

@@ -1,3 +1,4 @@
+import quic/openarray
 import ngtcp2
 import encrypt
 import decrypt
@@ -5,26 +6,21 @@ import hp
 import ids
 import keys
 import settings
+import params
+import crypto
 
 let zeroKey = Key()
-var cryptoData: array[4096, uint8]
 
 proc receiveClientInitial(connection: ptr ngtcp2_conn, dcid: ptr ngtcp2_cid, userData: pointer): cint {.cdecl.} =
   connection.install0RttKey(zeroKey)
   connection.installHandshakeKeys(zeroKey, zeroKey)
 
 proc receiveCryptoData(connection: ptr ngtcp2_conn, level: ngtcp2_crypto_level, offset: uint64, data: ptr uint8, datalen: uint, userData: pointer): cint {.cdecl.} =
-  assert 0 == ngtcp2_conn_submit_crypto_data(
-    connection,
-    if level == NGTCP2_CRYPTO_LEVEL_INITIAL: NGTCP2_CRYPTO_LEVEL_INITIAL else: NGTCP2_CRYPTO_LEVEL_HANDSHAKE,
-    addr cryptoData[0],
-    sizeof(cryptoData).uint
-  )
-
-  var params = defaultSettings().transport_params
-  params.initial_scid = connection.ngtcp2_conn_get_dcid()[]
+  var params = decodeTransportParameters(toOpenArray(data, datalen))
   assert 0 == ngtcp2_conn_set_remote_transport_params(connection, addr params)
 
+  connection.submitCryptoData()
+
   ngtcp2_conn_handshake_completed(connection)
 
 proc updateKey(conn: ptr ngtcp2_conn, rx_secret: ptr uint8, tx_secret: ptr uint8, rx_aead_ctx: ptr ngtcp2_crypto_aead_ctx, rx_iv: ptr uint8, tx_aead_ctx: ptr ngtcp2_crypto_aead_ctx, tx_iv: ptr uint8, current_rx_secret: ptr uint8, current_tx_secret: ptr uint8, secretlen: uint, user_data: pointer): cint {.cdecl} =