// Copyright 2018 The gRPC Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package grpc.gcp;

import "grpc/gcp/transport_security_common.proto";

option java_package = "io.grpc.alts.internal";

enum HandshakeProtocol {
  // Default value.
  HANDSHAKE_PROTOCOL_UNSPECIFIED = 0;

  // TLS handshake protocol.
  TLS = 1;

  // Application Layer Transport Security handshake protocol.
  ALTS = 2;
}

enum NetworkProtocol {
  NETWORK_PROTOCOL_UNSPECIFIED = 0;
  TCP = 1;
  UDP = 2;
}

message Endpoint {
  // IP address. It should contain an IPv4 or IPv6 string literal, e.g.
  // "192.168.0.1" or "2001:db8::1".
  string ip_address = 1;

  // Port number.
  int32 port = 2;

  // Network protocol (e.g., TCP, UDP) associated with this endpoint.
  NetworkProtocol protocol = 3;
}

message Identity {
  oneof identity_oneof {
    // Service account of a connection endpoint.
    string service_account = 1;

    // Hostname of a connection endpoint.
    string hostname = 2;
  }
}

message StartClientHandshakeReq {
  // Handshake security protocol requested by the client.
  HandshakeProtocol handshake_security_protocol = 1;

  // The application protocols supported by the client, e.g., "h2" (for http2),
  // "grpc".
  repeated string application_protocols = 2;

  // The record protocols supported by the client, e.g.,
  // "ALTSRP_GCM_AES128".
  repeated string record_protocols = 3;

  // (Optional) Describes which server identities are acceptable by the client.
  // If target identities are provided and none of them matches the peer
  // identity of the server, handshake will fail.
  repeated Identity target_identities = 4;

  // (Optional) Application may specify a local identity. Otherwise, the
  // handshaker chooses a default local identity.
  Identity local_identity = 5;

  // (Optional) Local endpoint information of the connection to the server,
  // such as local IP address, port number, and network protocol.
  Endpoint local_endpoint = 6;

  // (Optional) Endpoint information of the remote server, such as IP address,
  // port number, and network protocol.
  Endpoint remote_endpoint = 7;

  // (Optional) If target name is provided, a secure naming check is performed
  // to verify that the peer authenticated identity is indeed authorized to run
  // the target name.
  string target_name = 8;

  // (Optional) RPC protocol versions supported by the client.
  RpcProtocolVersions rpc_versions = 9;
}

message ServerHandshakeParameters {
  // The record protocols supported by the server, e.g.,
  // "ALTSRP_GCM_AES128".
  repeated string record_protocols = 1;

  // (Optional) A list of local identities supported by the server, if
  // specified. Otherwise, the handshaker chooses a default local identity.
  repeated Identity local_identities = 2;
}

message StartServerHandshakeReq {
  // The application protocols supported by the server, e.g., "h2" (for http2),
  // "grpc".
  repeated string application_protocols = 1;

  // Handshake parameters (record protocols and local identities supported by
  // the server) mapped by the handshake protocol. Each handshake security
  // protocol (e.g., TLS or ALTS) has its own set of record protocols and local
  // identities. Since protobuf does not support enum as key to the map, the key
  // to handshake_parameters is the integer value of HandshakeProtocol enum.
  map<int32, ServerHandshakeParameters> handshake_parameters = 2;

  // Bytes in out_frames returned from the peer's HandshakerResp. It is possible
  // that the peer's out_frames are split into multiple HandshakReq messages.
  bytes in_bytes = 3;

  // (Optional) Local endpoint information of the connection to the client,
  // such as local IP address, port number, and network protocol.
  Endpoint local_endpoint = 4;

  // (Optional) Endpoint information of the remote client, such as IP address,
  // port number, and network protocol.
  Endpoint remote_endpoint = 5;

  // (Optional) RPC protocol versions supported by the server.
  RpcProtocolVersions rpc_versions = 6;
}

message NextHandshakeMessageReq {
  // Bytes in out_frames returned from the peer's HandshakerResp. It is possible
  // that the peer's out_frames are split into multiple NextHandshakerMessageReq
  // messages.
  bytes in_bytes = 1;
}

message HandshakerReq {
  oneof req_oneof {
    // The start client handshake request message.
    StartClientHandshakeReq client_start = 1;

    // The start server handshake request message.
    StartServerHandshakeReq server_start = 2;

    // The next handshake request message.
    NextHandshakeMessageReq next = 3;
  }
}

message HandshakerResult {
  // The application protocol negotiated for this connection.
  string application_protocol = 1;

  // The record protocol negotiated for this connection.
  string record_protocol = 2;

  // Cryptographic key data. The key data may be more than the key length
  // required for the record protocol, thus the client of the handshaker
  // service needs to truncate the key data into the right key length.
  bytes key_data = 3;

  // The authenticated identity of the peer.
  Identity peer_identity = 4;

  // The local identity used in the handshake.
  Identity local_identity = 5;

  // Indicate whether the handshaker service client should keep the channel
  // between the handshaker service open, e.g., in order to handle
  // post-handshake messages in the future.
  bool keep_channel_open = 6;

  // The RPC protocol versions supported by the peer.
  RpcProtocolVersions peer_rpc_versions = 7;
}

message HandshakerStatus {
  // The status code. This could be the gRPC status code.
  uint32 code = 1;

  // The status details.
  string details = 2;
}

message HandshakerResp {
  // Frames to be given to the peer for the NextHandshakeMessageReq. May be
  // empty if no out_frames have to be sent to the peer or if in_bytes in the
  // HandshakerReq are incomplete. All the non-empty out frames must be sent to
  // the peer even if the handshaker status is not OK as these frames may
  // contain the alert frames.
  bytes out_frames = 1;

  // Number of bytes in the in_bytes consumed by the handshaker. It is possible
  // that part of in_bytes in HandshakerReq was unrelated to the handshake
  // process.
  uint32 bytes_consumed = 2;

  // This is set iff the handshake was successful. out_frames may still be set
  // to frames that needs to be forwarded to the peer.
  HandshakerResult result = 3;

  // Status of the handshaker.
  HandshakerStatus status = 4;
}

service HandshakerService {
  // Handshaker service accepts a stream of handshaker request, returning a
  // stream of handshaker response. Client is expected to send exactly one
  // message with either client_start or server_start followed by one or more
  // messages with next. Each time client sends a request, the handshaker
  // service expects to respond. Client does not have to wait for service's
  // response before sending next request.
  rpc DoHandshake(stream HandshakerReq)
      returns (stream HandshakerResp) {
  }
}