config: add proxy protocol config api message. (#10845)

Description: This PR creates a common PROXY protocol config API message. It will be used for  CONNECT work as well as in the transport socket for my upstream proxy proto work. This message could be extended to include TLVs in the future.

Risk Level: Low
Testing: None
Docs Changes: None
Release Notes: None
Discussed in: #10682 (my draft PR to discuss the upstream implementation)

Signed-off-by: Weston Carlson <wez470@gmail.com>

Mirrored from https://github.com/envoyproxy/envoy @ 1c28302b62bc4f5b93f2826eb06d2878069d9081

envoy/config/core/v3/proxy_protocol.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+
+package envoy.config.core.v3;
+
+import "udpa/annotations/status.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.config.core.v3";
+option java_outer_classname = "ProxyProtocolProto";
+option java_multiple_files = true;
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Proxy Protocol]
+
+message ProxyProtocolConfig {
+  enum Version {
+    // PROXY protocol version 1. Human readable format.
+    V1 = 0;
+
+    // PROXY protocol version 2. Binary format.
+    V2 = 1;
+  }
+
+  // The PROXY protocol version to use. See https://www.haproxy.org/download/2.1/doc/proxy-protocol.txt for details
+  Version version = 1;
+}

envoy/config/core/v4alpha/proxy_protocol.proto

@@ -0,0 +1,30 @@
+syntax = "proto3";
+
+package envoy.config.core.v4alpha;
+
+import "udpa/annotations/status.proto";
+import "udpa/annotations/versioning.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.config.core.v4alpha";
+option java_outer_classname = "ProxyProtocolProto";
+option java_multiple_files = true;
+option (udpa.annotations.file_status).package_version_status = NEXT_MAJOR_VERSION_CANDIDATE;
+
+// [#protodoc-title: Proxy Protocol]
+
+message ProxyProtocolConfig {
+  option (udpa.annotations.versioning).previous_message_type =
+      "envoy.config.core.v3.ProxyProtocolConfig";
+
+  enum Version {
+    // PROXY protocol version 1. Human readable format.
+    V1 = 0;
+
+    // PROXY protocol version 2. Binary format.
+    V2 = 1;
+  }
+
+  // The PROXY protocol version to use. See https://www.haproxy.org/download/2.1/doc/proxy-protocol.txt for details
+  Version version = 1;
+}