Add parsing code for RFC 5280 PolicyConstraints.

net/cert/internal/certificate_policies.h

 // Copyright 2015 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.
 
 #ifndef NET_CERT_INTERNAL_CERTIFICATE_POLICIES_H_
 #define NET_CERT_INTERNAL_CERTIFICATE_POLICIES_H_
 
+#include <stdint.h>
+
 #include <vector>
 
+#include "base/compiler_specific.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 namespace der {
 class Input;
 }  // namespace der
 
 // Returns the DER-encoded OID, without tag or length, of the anyPolicy
 // certificate policy defined in RFC 5280 section 4.2.1.4.
 NET_EXPORT const der::Input AnyPolicy();
 
 // Parses a certificatePolicies extension and stores the policy OIDs in
 // |*policies|, in sorted order. If policyQualifiers are present,
 // they are ignored. (RFC 5280 section 4.2.1.4 says "optional qualifiers, which
 // MAY be present, are not expected to change the definition of the policy.",
 // furthermore policyQualifiers do not affect the success or failure of the
 // section 6 Certification Path Validation algorithm.)
 //
 // The returned values is only valid as long as |extension_value| is.
 NET_EXPORT bool ParseCertificatePoliciesExtension(
     const der::Input& extension_value,
     std::vector<der::Input>* policies);
 
+struct ParsedPolicyConstraints {
+  bool has_require_explicit_policy = false;
+  uint8_t require_explicit_policy = 0;
+
+  bool has_inhibit_policy_mapping = false;
+  uint8_t inhibit_policy_mapping = 0;
+};
+
+// Parses a PolicyConstraints SEQUENCE as defined by RFC 5280. Returns true on
+// success, and sets |out|.
+NET_EXPORT bool ParsePolicyConstraints(const der::Input& policy_constraints_tlv,
+                                       ParsedPolicyConstraints* out)
+    WARN_UNUSED_RESULT;
+
 }  // namespace net
 
 #endif  // NET_CERT_INTERNAL_CERTIFICATE_POLICIES_H_