http: add CDN-Loop header value parser and utilities

CODEOWNERS

@@ -23,6 +23,8 @@ extensions/filters/common/original_src @snowp @klarose
 /*/extensions/filters/network/rocketmq_proxy @aaron-ai @lizhanhui @lizan
 # thrift_proxy extension
 /*/extensions/filters/network/thrift_proxy @zuercher @rgs1
+# cdn_loop extension
+/*/extensions/filters/http/cdn @justin-mp @penguingao @alyssawilk
 # compressor used by http compression filters
 /*/extensions/filters/http/common/compressor @gsagula @rojkov @dio
 /*/extensions/filters/http/compressor @rojkov @dio

source/extensions/filters/http/cdn_loop/BUILD

@@ -0,0 +1,26 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_library",
+    "envoy_extension_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_cc_library(
+    name = "parser_lib",
+    srcs = ["parser.cc"],
+    hdrs = ["parser.h"],
+    deps = ["//source/common/common:statusor_lib"],
+)
+
+envoy_cc_library(
+    name = "utils_lib",
+    srcs = ["utils.cc"],
+    hdrs = ["utils.h"],
+    deps = [
+        ":parser_lib",
+        "//source/common/common:statusor_lib",
+    ],
+)