// This is heavily derived from
// https://lyft.github.io/envoy/docs/configuration/listeners/listeners.html
// The v2 gRPC API differences are tagged with [V2-API-DIFF].

syntax = "proto3";

package envoy.api.v2;

import "api/address.proto";
import "api/base.proto";
import "api/tls_context.proto";

import "google/api/annotations.proto";
import "google/protobuf/struct.proto";
import "google/protobuf/wrappers.proto";

// The Envoy instance initiates an RPC at startup to discover a list of
// listeners. Updates are delivered via streaming from the LDS server and
// consist of a complete update of all listeners. Existing connections will be
// allowed to drain from listeners that are no longer present.
service ListenerDiscoveryService {
  rpc StreamListeners(ListenerDiscoveryRequest) returns
      (stream ListenerDiscoverResponse) {}

  rpc FetchListeners(ListenerDiscoveryRequest)
      returns (ListenerDiscoverResponse) {
    option (google.api.http) = {
      post: "/v2/discovery:listeners"
      body: "*"
    };
  }
}

message ListenerDiscoveryRequest {
  Node node = 1;
}

message ListenerDiscoverResponse {
  repeated Listener listeners = 1;
}

message Filter {
  // The type of filter to instantiate. Most filters implement a specific type,
  // though it is theoretically possible for a filter to be written such that it
  // can operate in multiple modes. Supported types are read, write, and both.
  enum Type {
    BOTH = 0;
    READ = 1;
    WRITE = 2;
  }
  Type type = 1;
  // The name of the filter to instantiate. The name must match a supported
  // filter.
  string name = 2;
  // Filter specific configuration which depends on the filter being
  // instantiated. See the supported filters for further documentation.
  google.protobuf.Struct config = 3;
}

// Specifies the match criteria for selecting a specific filter chain for a
// listener [V2-API-DIFF].
message FilterChainMatch {
  // If non-empty, the SNI domains to consider. May contain a wildcard prefix,
  // e.g. *.example.com.
  repeated string sni_domains = 1;

  // If non-empty, an IP address and prefix length to match addresses when the
  // listener is bound to 0.0.0.0/::.
  string address_prefix = 2;
  google.protobuf.UInt32Value prefix_len = 3;

  // If non-empty, an IP address and suffix length to match addresses when the
  // listener is bound to 0.0.0.0/::.
  string address_suffix = 4;
  google.protobuf.UInt32Value suffix_len = 5;
}

// Grouping of FilterChainMatch criteria, DownstreamTlsContext, the actual filter chain
// and related parameters.
message FilterChain {
  FilterChainMatch filter_chain_match = 1;
  DownstreamTlsContext tls_context = 2;
  // A list of individual network filters that make up the filter chain for
  // connections established with the listener. Order matters as the filters are
  // processed sequentially as connection events happen.  Note: If the filter
  // list is empty, the connection will close by default.
  repeated Filter filter_chain = 3;

  // Whether the listener should expect a PROXY protocol V1 header on new
  // connections. If this option is enabled, the listener will assume that that
  // remote address of the connection is the one specified in the header. Some
  // load balancers including the AWS ELB support this option. If the option is
  // absent or set to false, Envoy will use the physical peer address of the
  // connection as the remote address.
  google.protobuf.BoolValue use_proxy_proto = 4;
}

message Listener {
  // The address that the listener should listen on.
  UnresolvedAddress address = 1;

  // A list of filter chains to consider for this listener. The FilterChain with
  // the most specific FilterChainMatch criteria is used on a connection. The
  // algorithm works as follows:
  // 1. If SNI information is presented at connection time, only the
  //    FilterChains matching the SNI are considered. Otherwise, only
  //    FilterChains with no SNI domains are considered.
  // 2. Of the FilterChains from step 1, the longest prefix match on the
  //    bound destination address is used to select the next set of
  //    FilterChains. This may be one FilterChain or multiple if there is
  //    a tie.
  // 3. The longest suffix match on the bound destination address is used to
  //    select the FilterChain from step 2 that is used.
  repeated FilterChain filter_chains = 2;

  // Whether the listener should not bind to the port. A listener that doesn’t bind
  // can only receive connections redirected from other listeners that set
  // use_origin_dst parameter to true. Default is true.
  google.protobuf.BoolValue bind_to_port = 3;

  // If a connection is redirected using iptables, the port on which the proxy
  // receives it might be different from the original destination port. When
  // this flag is set to true, the listener hands off redirected connections to
  // the listener associated with the original destination port. If there is no
  // listener associated with the original destination port, the connection is
  // handled by the listener that receives it. Default is false.
  // TODO(htuch): Clarify how use_original_dst interacts with listeners that
  // bind to specific IP addresses, where we want the original destination IP to
  // be used in the FilterChainMatch but not on bind.
  google.protobuf.BoolValue use_original_dst = 4;

  // Soft limit on size of the listener’s new connection read and write buffers.
  // If unspecified, an implementation defined default is applied (1MiB).
  google.protobuf.UInt32Value per_connection_buffer_limit_bytes = 5;
}