Implement SDCH Dictionary domain matching as per RFC 2965

net/base/url_util.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/url_util.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include <netinet/in.h>
@@ skipping 420 matching lines @@
     return true;
   }
 
   if (is_local6)
     *is_local6 = false;
   return normalized_host == "localhost" ||
          normalized_host == "localhost.localdomain" ||
          IsNormalizedLocalhostTLD(normalized_host);
 }
 
+bool IsDomainMatch(const std::string& domain, const std::string& host) {
+  // Can domain match in two ways; as a domain cookie (where the cookie
+  // domain begins with ".") or as a host cookie (where it doesn't).
+
+  // Some consumers of the CookieMonster expect to set cookies on
+  // URLs like http://.strange.url.  To retrieve cookies in this instance,
+  // we allow matching as a host cookie even when the domain_ starts with
+  // a period.
+  if (host == domain)
+    return true;
+
+  // Domain cookie must have an initial ".".  To match, it must be
+  // equal to url's host with initial period removed, or a suffix of
+  // it.
+
+  // Arguably this should only apply to "http" or "https" cookies, but
+  // extension cookie tests currently use the funtionality, and if we
+  // ever decide to implement that it should be done by preventing
+  // such cookies from being set.
+  if (domain.empty() || domain[0] != '.')
+    return false;
+
+  // The host with a "." prefixed.
+  if (domain.compare(1, std::string::npos, host) == 0)
+    return true;
+
+  // A pure suffix of the host (ok since we know the domain already
+  // starts with a ".")
+  return (host.length() > domain.length() &&
+          host.compare(host.length() - domain.length(), domain.length(),
+                       domain) == 0);
+}
+
 }  // namespace net