feat(nodes): Implement GatewayManager (#204)

src/main/kotlin/tech/relaycorp/relaynet/messages/payloads/CargoCollectionRequest.kt

@@ -7,7 +7,9 @@ import tech.relaycorp.relaynet.wrappers.asn1.ASN1Utils
 import tech.relaycorp.relaynet.wrappers.x509.Certificate
 import tech.relaycorp.relaynet.wrappers.x509.CertificateException
 
-class CargoCollectionRequest(val cargoDeliveryAuthorization: Certificate) : EncryptedPayload() {
+class CargoCollectionRequest(
+    val cargoDeliveryAuthorization: Certificate
+) : GatewayEncryptedPayload() {
     override fun serializePlaintext(): ByteArray {
         val cdaASN1 = DEROctetString(cargoDeliveryAuthorization.serialize())
         return ASN1Utils.serializeSequence(listOf(cdaASN1), false)

src/main/kotlin/tech/relaycorp/relaynet/messages/payloads/CargoMessageSet.kt

@@ -8,7 +8,7 @@ import tech.relaycorp.relaynet.wrappers.asn1.ASN1Utils
 /**
  * Cargo message set.
  */
-class CargoMessageSet(val messages: Array<ByteArray>) : EncryptedPayload() {
+class CargoMessageSet(val messages: Array<ByteArray>) : GatewayEncryptedPayload() {
     /**
      * Serialize cargo message set.
      */

src/main/kotlin/tech/relaycorp/relaynet/messages/payloads/GatewayEncryptedPayload.kt

@@ -0,0 +1,3 @@
+package tech.relaycorp.relaynet.messages.payloads
+
+abstract class GatewayEncryptedPayload : EncryptedPayload()

src/main/kotlin/tech/relaycorp/relaynet/nodes/GatewayManager.kt

@@ -0,0 +1,11 @@
+package tech.relaycorp.relaynet.nodes
+
+import tech.relaycorp.relaynet.keystores.PrivateKeyStore
+import tech.relaycorp.relaynet.keystores.SessionPublicKeyStore
+import tech.relaycorp.relaynet.messages.payloads.GatewayEncryptedPayload
+
+class GatewayManager(
+    privateKeyStore: PrivateKeyStore,
+    sessionPublicKeyStore: SessionPublicKeyStore,
+    cryptoOptions: NodeCryptoOptions = NodeCryptoOptions(),
+) : NodeManager<GatewayEncryptedPayload> (privateKeyStore, sessionPublicKeyStore, cryptoOptions)

src/test/kotlin/tech/relaycorp/relaynet/nodes/GatewayManagerTest.kt

@@ -0,0 +1,37 @@
+package tech.relaycorp.relaynet.nodes
+
+import kotlin.test.assertEquals
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import tech.relaycorp.relaynet.ECDHCurve
+import tech.relaycorp.relaynet.HashingAlgorithm
+import tech.relaycorp.relaynet.SymmetricCipher
+import tech.relaycorp.relaynet.utils.MockPrivateKeyStore
+import tech.relaycorp.relaynet.utils.MockSessionPublicKeyStore
+
+class GatewayManagerTest {
+    private val privateKeyStore = MockPrivateKeyStore()
+    private val sessionPublicKeyStore = MockSessionPublicKeyStore()
+
+    @Nested
+    inner class Constructor {
+        @Test
+        fun `Default crypto algorithms should be used by default`() {
+            val gatewayManager = GatewayManager(privateKeyStore, sessionPublicKeyStore)
+
+            assertEquals(NodeCryptoOptions(), gatewayManager.cryptoOptions)
+        }
+
+        @Test
+        fun `Custom crypto algorithms should be honored`() {
+            val options = NodeCryptoOptions(
+                ECDHCurve.P521,
+                SymmetricCipher.AES_256,
+                HashingAlgorithm.SHA512,
+            )
+            val gatewayManager = GatewayManager(privateKeyStore, sessionPublicKeyStore, options)
+
+            assertEquals(options, gatewayManager.cryptoOptions)
+        }
+    }
+}