/*
* X.509 Certificate Extensions
* (C) 1999-2007,2012 Jack Lloyd
* (C) 2024 Anton Einax, Dominik Schricker
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_X509_EXTENSIONS_H_
#define BOTAN_X509_EXTENSIONS_H_

#include <botan/pkix_types.h>

#include <array>
#include <memory>
#include <optional>
#include <set>
#include <string>
#include <string_view>
#include <vector>

namespace Botan {

class X509_Certificate;

namespace Cert_Extension {

static const size_t NO_CERT_PATH_LIMIT = 0xFFFFFFF0;

/**
* Basic Constraints Extension
*/
class BOTAN_PUBLIC_API(2, 0) Basic_Constraints final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Basic_Constraints>(m_is_ca, m_path_length_constraint);
      }

      BOTAN_FUTURE_EXPLICIT Basic_Constraints(bool is_ca = false, size_t path_length_constraint = 0);

      Basic_Constraints(bool is_ca, std::optional<size_t> path_length_constraint);

      BOTAN_DEPRECATED("Use is_ca") bool get_is_ca() const { return m_is_ca; }

      /**
      * Note that this function returns NO_CERT_PATH_LIMIT if the value was not set
      * in the extension.
      */
      BOTAN_DEPRECATED("Use path_length_constraint") size_t get_path_limit() const;

      bool is_ca() const { return m_is_ca; }

      std::optional<size_t> path_length_constraint() const { return m_path_length_constraint; }

      static OID static_oid() { return OID({2, 5, 29, 19}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.BasicConstraints"; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      bool m_is_ca;
      std::optional<size_t> m_path_length_constraint;
};

/**
* Key Usage Constraints Extension
*/
class BOTAN_PUBLIC_API(2, 0) Key_Usage final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Key_Usage>(m_constraints);
      }

      explicit Key_Usage(Key_Constraints c) : m_constraints(c) {}

      explicit Key_Usage() : m_constraints(Key_Constraints::None) {}

      Key_Constraints get_constraints() const { return m_constraints; }

      static OID static_oid() { return OID({2, 5, 29, 15}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.KeyUsage"; }

      bool should_encode() const override { return !m_constraints.empty(); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      Key_Constraints m_constraints;
};

/**
* Subject Key Identifier Extension
*/
class BOTAN_PUBLIC_API(2, 0) Subject_Key_ID final : public Certificate_Extension {
   public:
      Subject_Key_ID() = default;

      explicit Subject_Key_ID(const std::vector<uint8_t>& k) : m_key_id(k) {}

      Subject_Key_ID(const std::vector<uint8_t>& public_key, std::string_view hash_fn);

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Subject_Key_ID>(m_key_id);
      }

      const std::vector<uint8_t>& get_key_id() const { return m_key_id; }

      static OID static_oid() { return OID({2, 5, 29, 14}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.SubjectKeyIdentifier"; }

      bool should_encode() const override { return (!m_key_id.empty()); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<uint8_t> m_key_id;
};

/**
* Authority Key Identifier Extension
*/
class BOTAN_PUBLIC_API(2, 0) Authority_Key_ID final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Authority_Key_ID>(m_key_id);
      }

      Authority_Key_ID() = default;

      explicit Authority_Key_ID(const std::vector<uint8_t>& k) : m_key_id(k) {}

      const std::vector<uint8_t>& get_key_id() const { return m_key_id; }

      static OID static_oid() { return OID({2, 5, 29, 35}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.AuthorityKeyIdentifier"; }

      bool should_encode() const override { return (!m_key_id.empty()); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<uint8_t> m_key_id;
};

/**
* Subject Alternative Name Extension
*/
class BOTAN_PUBLIC_API(2, 4) Subject_Alternative_Name final : public Certificate_Extension {
   public:
      const AlternativeName& get_alt_name() const { return m_alt_name; }

      static OID static_oid() { return OID({2, 5, 29, 17}); }

      OID oid_of() const override { return static_oid(); }

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Subject_Alternative_Name>(get_alt_name());
      }

      explicit Subject_Alternative_Name(const AlternativeName& name = AlternativeName()) : m_alt_name(name) {}

   private:
      std::string oid_name() const override { return "X509v3.SubjectAlternativeName"; }

      bool should_encode() const override { return m_alt_name.has_items(); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      AlternativeName m_alt_name;
};

/**
* Issuer Alternative Name Extension
*/
class BOTAN_PUBLIC_API(2, 0) Issuer_Alternative_Name final : public Certificate_Extension {
   public:
      const AlternativeName& get_alt_name() const { return m_alt_name; }

      static OID static_oid() { return OID({2, 5, 29, 18}); }

      OID oid_of() const override { return static_oid(); }

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Issuer_Alternative_Name>(get_alt_name());
      }

      explicit Issuer_Alternative_Name(const AlternativeName& name = AlternativeName()) : m_alt_name(name) {}

   private:
      std::string oid_name() const override { return "X509v3.IssuerAlternativeName"; }

      bool should_encode() const override { return m_alt_name.has_items(); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      AlternativeName m_alt_name;
};

/**
* Extended Key Usage Extension
*/
class BOTAN_PUBLIC_API(2, 0) Extended_Key_Usage final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Extended_Key_Usage>(m_oids);
      }

      Extended_Key_Usage() = default;

      explicit Extended_Key_Usage(const std::vector<OID>& o) : m_oids(o) {}

      const std::vector<OID>& object_identifiers() const { return m_oids; }

      static OID static_oid() { return OID({2, 5, 29, 37}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.ExtendedKeyUsage"; }

      bool should_encode() const override { return (!m_oids.empty()); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<OID> m_oids;
};

/**
* Name Constraints
*/
class BOTAN_PUBLIC_API(2, 0) Name_Constraints final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Name_Constraints>(m_name_constraints);
      }

      Name_Constraints() = default;

      BOTAN_FUTURE_EXPLICIT Name_Constraints(const NameConstraints& nc) : m_name_constraints(nc) {}

      void validate(const X509_Certificate& subject,
                    const X509_Certificate& issuer,
                    const std::vector<X509_Certificate>& cert_path,
                    std::vector<std::set<Certificate_Status_Code>>& cert_status,
                    size_t pos) override;

      const NameConstraints& get_name_constraints() const { return m_name_constraints; }

      static OID static_oid() { return OID({2, 5, 29, 30}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.NameConstraints"; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      NameConstraints m_name_constraints;
};

/**
* Certificate Policies Extension
*/
class BOTAN_PUBLIC_API(2, 0) Certificate_Policies final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Certificate_Policies>(m_oids);
      }

      Certificate_Policies() = default;

      explicit Certificate_Policies(const std::vector<OID>& o) : m_oids(o) {}

      const std::vector<OID>& get_policy_oids() const { return m_oids; }

      static OID static_oid() { return OID({2, 5, 29, 32}); }

      OID oid_of() const override { return static_oid(); }

      void validate(const X509_Certificate& subject,
                    const X509_Certificate& issuer,
                    const std::vector<X509_Certificate>& cert_path,
                    std::vector<std::set<Certificate_Status_Code>>& cert_status,
                    size_t pos) override;

   private:
      std::string oid_name() const override { return "X509v3.CertificatePolicies"; }

      bool should_encode() const override { return (!m_oids.empty()); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<OID> m_oids;
};

/**
* Authority Information Access Extension
*/
class BOTAN_PUBLIC_API(2, 0) Authority_Information_Access final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Authority_Information_Access>(m_ocsp_responder, m_ca_issuers);
      }

      Authority_Information_Access() = default;

      explicit Authority_Information_Access(std::string_view ocsp,
                                            const std::vector<std::string>& ca_issuers = std::vector<std::string>()) :
            m_ocsp_responder(ocsp), m_ca_issuers(ca_issuers) {}

      std::string ocsp_responder() const { return m_ocsp_responder; }

      static OID static_oid() { return OID({1, 3, 6, 1, 5, 5, 7, 1, 1}); }

      OID oid_of() const override { return static_oid(); }

      const std::vector<std::string>& ca_issuers() const { return m_ca_issuers; }

   private:
      std::string oid_name() const override { return "PKIX.AuthorityInformationAccess"; }

      bool should_encode() const override { return (!m_ocsp_responder.empty() || !m_ca_issuers.empty()); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::string m_ocsp_responder;
      std::vector<std::string> m_ca_issuers;
};

/**
* CRL Number Extension
*/
class BOTAN_PUBLIC_API(2, 0) CRL_Number final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override;

      CRL_Number() : m_has_value(false), m_crl_number(0) {}

      BOTAN_FUTURE_EXPLICIT CRL_Number(size_t n) : m_has_value(true), m_crl_number(n) {}

      size_t get_crl_number() const;

      static OID static_oid() { return OID({2, 5, 29, 20}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.CRLNumber"; }

      bool should_encode() const override { return m_has_value; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      bool m_has_value;
      size_t m_crl_number;
};

/**
* CRL Entry Reason Code Extension
*/
class BOTAN_PUBLIC_API(2, 0) CRL_ReasonCode final : public Certificate_Extension {
   public:
      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<CRL_ReasonCode>(m_reason);
      }

      explicit CRL_ReasonCode(CRL_Code r = CRL_Code::Unspecified) : m_reason(r) {}

      CRL_Code get_reason() const { return m_reason; }

      static OID static_oid() { return OID({2, 5, 29, 21}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.ReasonCode"; }

      bool should_encode() const override { return (m_reason != CRL_Code::Unspecified); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      CRL_Code m_reason;
};

/**
* CRL Distribution Points Extension
* todo enforce restrictions from RFC 5280 4.2.1.13
*/
class BOTAN_PUBLIC_API(2, 0) CRL_Distribution_Points final : public Certificate_Extension {
   public:
      class BOTAN_PUBLIC_API(2, 0) Distribution_Point final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            explicit Distribution_Point(const AlternativeName& name = AlternativeName()) : m_point(name) {}

            const AlternativeName& point() const { return m_point; }

         private:
            AlternativeName m_point;
      };

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<CRL_Distribution_Points>(m_distribution_points);
      }

      CRL_Distribution_Points() = default;

      explicit CRL_Distribution_Points(const std::vector<Distribution_Point>& points) : m_distribution_points(points) {}

      const std::vector<Distribution_Point>& distribution_points() const { return m_distribution_points; }

      const std::vector<std::string>& crl_distribution_urls() const { return m_crl_distribution_urls; }

      static OID static_oid() { return OID({2, 5, 29, 31}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.CRLDistributionPoints"; }

      bool should_encode() const override { return !m_distribution_points.empty(); }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<Distribution_Point> m_distribution_points;
      std::vector<std::string> m_crl_distribution_urls;
};

/**
* CRL Issuing Distribution Point Extension
* todo enforce restrictions from RFC 5280 5.2.5
*/
class CRL_Issuing_Distribution_Point final : public Certificate_Extension {
   public:
      CRL_Issuing_Distribution_Point() = default;

      explicit CRL_Issuing_Distribution_Point(const CRL_Distribution_Points::Distribution_Point& distribution_point) :
            m_distribution_point(distribution_point) {}

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<CRL_Issuing_Distribution_Point>(m_distribution_point);
      }

      const AlternativeName& get_point() const { return m_distribution_point.point(); }

      static OID static_oid() { return OID({2, 5, 29, 28}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "X509v3.CRLIssuingDistributionPoint"; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      CRL_Distribution_Points::Distribution_Point m_distribution_point;
};

/**
* OCSP NoCheck Extension
*
* RFC6960 4.2.2.2.1
*    A CA may specify that an OCSP client can trust a responder for the
*    lifetime of the responder's certificate.  The CA does so by
*    including the extension id-pkix-ocsp-nocheck.
*
* In other words: OCSP responder certificates with this extension do not need
*                 to be validated against some revocation info.
*/
class OCSP_NoCheck final : public Certificate_Extension {
   public:
      OCSP_NoCheck() = default;

      std::unique_ptr<Certificate_Extension> copy() const override { return std::make_unique<OCSP_NoCheck>(); }

      static OID static_oid() { return OID({1, 3, 6, 1, 5, 5, 7, 48, 1, 5}); }

      OID oid_of() const override { return static_oid(); }

   private:
      std::string oid_name() const override { return "PKIX.OCSP.NoCheck"; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override { return {}; }

      void decode_inner(const std::vector<uint8_t>& in) override;
};

/**
* TNAuthList extension
*
* RFC8226 Secure Telephone Identity Credentials
*   https://www.rfc-editor.org/rfc/rfc8226#section-9
*/
class BOTAN_PUBLIC_API(3, 5) TNAuthList final : public Certificate_Extension {
   public:
      class BOTAN_PUBLIC_API(3, 5) Entry final : public ASN1_Object {
         public:
            /* TNEntry choice values
             * see: https://datatracker.ietf.org/doc/html/rfc8226#section-9 */
            enum Type : uint8_t { ServiceProviderCode = 0, TelephoneNumberRange = 1, TelephoneNumber = 2 };

            struct TelephoneNumberRangeData {
                  ASN1_String start;  //TelephoneNumber (IA5String)
                  size_t count{};     //2..MAX
            };

            using RangeContainer = std::vector<TelephoneNumberRangeData>;
            using DataContainer = std::variant<ASN1_String, RangeContainer>;

            void encode_into(DER_Encoder& to) const override;
            void decode_from(class BER_Decoder& from) override;

            Type type() const { return m_type; }

            const std::string& service_provider_code() const;

            const RangeContainer& telephone_number_range() const;

            const std::string& telephone_number() const;

         private:
            Type m_type{};
            DataContainer m_data;
      };

      TNAuthList() = default;

      std::unique_ptr<Certificate_Extension> copy() const override { return std::make_unique<TNAuthList>(*this); }

      static OID static_oid() { return OID({1, 3, 6, 1, 5, 5, 7, 1, 26}); }

      OID oid_of() const override { return static_oid(); }

      const std::vector<Entry>& entries() const { return m_tn_entries; }

   private:
      std::string oid_name() const override { return "PKIX.TNAuthList"; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<Entry> m_tn_entries;
};

/**
 * IP Address Blocks Extension
 *
 * RFC 3779 X.509 Extensions for IP Addr
 *
*/
class BOTAN_PUBLIC_API(3, 9) IPAddressBlocks final : public Certificate_Extension {
   public:
      enum class BOTAN_PUBLIC_API(3, 9) Version : uint8_t {
         IPv4 = 4,
         IPv6 = 16,
      };

      template <Version V>
      class BOTAN_PUBLIC_API(3, 9) IPAddress final {
            static constexpr size_t Length = static_cast<size_t>(V);

         public:
            explicit IPAddress(std::span<const uint8_t> v);

            std::array<uint8_t, Length> value() const { return m_value; }

         private:
            friend class IPAddressBlocks;
            IPAddress() = default;

            void next() {
               for(auto it = m_value.rbegin(); it != m_value.rend(); it++) {
                  // we increment the current octet
                  (*it)++;
                  // if it did not wrap around we are done, else look at the next octet
                  if(*it != 0) {
                     break;
                  }
               }
            }

            friend IPAddress<V> operator+(IPAddress<V> lhs, size_t rhs) {
               // we only really need to be able to compute +1, so this is fine
               for(size_t i = 0; i < rhs; i++) {
                  lhs.next();
               }
               return IPAddress<V>(lhs);
            }

            friend std::strong_ordering operator<=>(const IPAddress<V> lhs, const IPAddress<V>& rhs) {
               for(size_t i = 0; i < Length; i++) {
                  if(lhs.value()[i] < rhs.value()[i]) {
                     return std::strong_ordering::less;
                  } else if(lhs.value()[i] > rhs.value()[i]) {
                     return std::strong_ordering::greater;
                  }
               }
               return std::strong_ordering::equal;
            }

            friend bool operator==(const IPAddress<V>& lhs, const IPAddress<V>& rhs) {
               return lhs.value() == rhs.value();
            }

            std::array<uint8_t, Length> m_value;
      };

      template <Version V>
      class BOTAN_PUBLIC_API(3, 9) IPAddressOrRange final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            IPAddressOrRange() = default;

            explicit IPAddressOrRange(const IPAddress<V>& addr) : m_min(addr), m_max(addr) {}

            IPAddressOrRange(const IPAddress<V>& min, const IPAddress<V>& max) : m_min(min), m_max(max) {
               if(max < min) {
                  throw Decoding_Error("IP address ranges must be sorted");
               }
            }

            IPAddress<V> min() const { return m_min; }

            IPAddress<V> max() const { return m_max; }

         private:
            IPAddress<V> m_min{};
            IPAddress<V> m_max{};

            IPAddress<V> decode_single_address(std::vector<uint8_t> decoded, bool min);
      };

      template <Version V>
      class BOTAN_PUBLIC_API(3, 9) IPAddressChoice final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            const std::optional<std::vector<IPAddressOrRange<V>>>& ranges() const { return m_ip_addr_ranges; }

            IPAddressChoice() = default;

            explicit IPAddressChoice(std::optional<std::span<const IPAddressOrRange<V>>> ranges);

         private:
            std::optional<std::vector<IPAddressOrRange<V>>> m_ip_addr_ranges;
      };

      class BOTAN_PUBLIC_API(3, 9) IPAddressFamily final : public ASN1_Object {
         public:
            typedef std::variant<IPAddressChoice<Version::IPv4>, IPAddressChoice<Version::IPv6>> AddrChoice;

            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            IPAddressFamily() = default;

            explicit IPAddressFamily(const AddrChoice& choice, std::optional<uint8_t> safi = std::nullopt) :
                  m_safi(safi), m_ip_addr_choice(choice) {
               if(std::holds_alternative<IPAddressChoice<Version::IPv4>>(choice)) {
                  m_afi = 1;
               } else {
                  m_afi = 2;
               }
            }

            uint16_t afi() const { return m_afi; }

            std::optional<uint8_t> safi() const { return m_safi; }

            const AddrChoice& addr_choice() const { return m_ip_addr_choice; }

         private:
            uint16_t m_afi = 1;
            std::optional<uint8_t> m_safi;
            AddrChoice m_ip_addr_choice;
      };

      IPAddressBlocks() = default;

      explicit IPAddressBlocks(const std::vector<IPAddressFamily>& blocks) : m_ip_addr_blocks(blocks) {
         this->sort_and_merge();
      }

      std::unique_ptr<Certificate_Extension> copy() const override { return std::make_unique<IPAddressBlocks>(*this); }

      static OID static_oid() { return OID({1, 3, 6, 1, 5, 5, 7, 1, 7}); }

      OID oid_of() const override { return static_oid(); }

      void validate(const X509_Certificate& subject,
                    const X509_Certificate& issuer,
                    const std::vector<X509_Certificate>& cert_path,
                    std::vector<std::set<Certificate_Status_Code>>& cert_status,
                    size_t pos) override;

      /// Add a single IP address to this extension (for the specified SAFI, if any)
      template <Version V>
      void add_address(const std::array<uint8_t, static_cast<size_t>(V)>& address,
                       std::optional<uint8_t> safi = std::nullopt) {
         add_address<V>(address, address, safi);
      }

      /// Add an IP address range to this extension (for the specified SAFI, if any)
      template <Version V>
      void add_address(const std::array<uint8_t, static_cast<std::size_t>(V)>& min,
                       const std::array<uint8_t, static_cast<std::size_t>(V)>& max,
                       std::optional<uint8_t> safi = std::nullopt) {
         std::vector<IPAddressOrRange<V>> addresses = {IPAddressOrRange<V>(IPAddress<V>(min), IPAddress<V>(max))};
         m_ip_addr_blocks.push_back(IPAddressFamily(IPAddressChoice<V>(addresses), safi));
         sort_and_merge();
      }

      /// Make the extension contain no allowed IP addresses for the specified IP version (and SAFI, if any)
      template <Version V>
      void restrict(std::optional<uint8_t> safi = std::nullopt) {
         std::vector<IPAddressOrRange<V>> addresses = {};
         m_ip_addr_blocks.push_back(IPAddressFamily(IPAddressChoice<V>(addresses), safi));
         sort_and_merge();
      }

      /// Mark the specified IP version as 'inherit' (for the specified SAFI, if any)
      template <Version V>
      void inherit(std::optional<uint8_t> safi = std::nullopt) {
         m_ip_addr_blocks.push_back(IPAddressFamily(IPAddressChoice<V>(), safi));
         sort_and_merge();
      }

      const std::vector<IPAddressFamily>& addr_blocks() const { return m_ip_addr_blocks; }

   private:
      std::string oid_name() const override { return "PKIX.IpAddrBlocks"; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      std::vector<IPAddressFamily> m_ip_addr_blocks;

      void sort_and_merge();
      template <Version V>
      IPAddressFamily merge(std::vector<IPAddressFamily>& blocks);
};

/**
 * AS Blocks Extension
 *
 * RFC 3779 X.509 Extensions for AS ID
 *
*/
class BOTAN_PUBLIC_API(3, 9) ASBlocks final : public Certificate_Extension {
   public:
      typedef uint32_t asnum_t;

      class BOTAN_PUBLIC_API(3, 9) ASIdOrRange final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            asnum_t min() const { return m_min; }

            asnum_t max() const { return m_max; }

            ASIdOrRange() = default;

            explicit ASIdOrRange(asnum_t id) : m_min(id), m_max(id) {}

            ASIdOrRange(asnum_t min, asnum_t max) : m_min(min), m_max(max) {
               if(max < min) {
                  throw Decoding_Error("AS range numbers must be sorted");
               }
            }

         private:
            asnum_t m_min = 0;
            asnum_t m_max = 0;
      };

      class BOTAN_PUBLIC_API(3, 9) ASIdentifierChoice final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            ASIdentifierChoice() = default;

            explicit ASIdentifierChoice(const std::optional<std::vector<ASIdOrRange>>& ranges);

            const std::optional<std::vector<ASIdOrRange>>& ranges() const { return m_as_ranges; }

         private:
            std::optional<std::vector<ASIdOrRange>> m_as_ranges;
      };

      class BOTAN_PUBLIC_API(3, 9) ASIdentifiers final : public ASN1_Object {
         public:
            void encode_into(DER_Encoder& to) const override;
            void decode_from(BER_Decoder& from) override;

            explicit ASIdentifiers(const std::optional<ASIdentifierChoice>& asnum,
                                   const std::optional<ASIdentifierChoice>& rdi) :
                  m_asnum(asnum), m_rdi(rdi) {
               if(!m_asnum.has_value() && !m_rdi.has_value()) {
                  throw Decoding_Error("One of asnum, rdi must be present");
               }
            }

            const std::optional<ASIdentifierChoice>& asnum() const { return m_asnum; }

            const std::optional<ASIdentifierChoice>& rdi() const { return m_rdi; }

         private:
            friend class ASBlocks;
            ASIdentifiers() = default;

            std::optional<ASIdentifierChoice> m_asnum;
            std::optional<ASIdentifierChoice> m_rdi;
      };

      ASBlocks() = default;

      explicit ASBlocks(const ASIdentifiers& as_idents) : m_as_identifiers(as_idents) {}

      std::unique_ptr<Certificate_Extension> copy() const override { return std::make_unique<ASBlocks>(*this); }

      static OID static_oid() { return OID({1, 3, 6, 1, 5, 5, 7, 1, 8}); }

      OID oid_of() const override { return static_oid(); }

      void validate(const X509_Certificate& subject,
                    const X509_Certificate& issuer,
                    const std::vector<X509_Certificate>& cert_path,
                    std::vector<std::set<Certificate_Status_Code>>& cert_status,
                    size_t pos) override;

      /// Add a single asnum to this extension
      void add_asnum(asnum_t asnum) { add_asnum(asnum, asnum); }

      /// Add an asnum range to this extension
      void add_asnum(asnum_t min, asnum_t max) {
         m_as_identifiers = ASIdentifiers(add_new(m_as_identifiers.asnum(), min, max), m_as_identifiers.rdi());
      }

      /// Make the extension contain no allowed asnum's
      void restrict_asnum() {
         std::vector<ASIdOrRange> empty;
         m_as_identifiers = ASIdentifiers(ASIdentifierChoice(empty), m_as_identifiers.rdi());
      }

      /// Mark the asnum entry as 'inherit'
      void inherit_asnum() { m_as_identifiers = ASIdentifiers(ASIdentifierChoice(), m_as_identifiers.rdi()); }

      /// Add a single rdi to this extension
      void add_rdi(asnum_t rdi) { add_rdi(rdi, rdi); }

      /// Add an rdi range to this extension
      void add_rdi(asnum_t min, asnum_t max) {
         m_as_identifiers = ASIdentifiers(m_as_identifiers.asnum(), add_new(m_as_identifiers.rdi(), min, max));
      }

      /// Make the extension contain no allowed rdi's
      void restrict_rdi() {
         std::vector<ASIdOrRange> empty;
         m_as_identifiers = ASIdentifiers(m_as_identifiers.asnum(), ASIdentifierChoice(empty));
      }

      /// Mark the rdi entry as 'inherit'
      void inherit_rdi() { m_as_identifiers = ASIdentifiers(m_as_identifiers.asnum(), ASIdentifierChoice()); }

      const ASIdentifiers& as_identifiers() const { return m_as_identifiers; }

   private:
      ASIdentifiers m_as_identifiers;

      std::string oid_name() const override { return "PKIX.AutonomousSysIds"; }

      bool should_encode() const override { return true; }

      static ASIdentifierChoice add_new(const std::optional<ASIdentifierChoice>& old, asnum_t min, asnum_t max);

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;
};

/**
* An unknown X.509 extension
* Will add a failure to the path validation result, if critical
*/
class BOTAN_PUBLIC_API(2, 4) Unknown_Extension final : public Certificate_Extension {
   public:
      Unknown_Extension(const OID& oid, bool critical) : m_oid(oid), m_critical(critical) {}

      std::unique_ptr<Certificate_Extension> copy() const override {
         return std::make_unique<Unknown_Extension>(m_oid, m_critical);
      }

      /**
      * Return the OID of this unknown extension
      */
      OID oid_of() const override { return m_oid; }

      //static_oid not defined for Unknown_Extension

      /**
      * Return the extension contents
      */
      const std::vector<uint8_t>& extension_contents() const { return m_bytes; }

      /**
      * Return if this extension was marked critical
      */
      bool is_critical_extension() const { return m_critical; }

      void validate(const X509_Certificate& /*subject*/,
                    const X509_Certificate& /*issuer*/,
                    const std::vector<X509_Certificate>& /*cert_path*/,
                    std::vector<std::set<Certificate_Status_Code>>& cert_status,
                    size_t pos) override {
         if(m_critical) {
            cert_status.at(pos).insert(Certificate_Status_Code::UNKNOWN_CRITICAL_EXTENSION);
         }
      }

   private:
      std::string oid_name() const override { return ""; }

      bool should_encode() const override { return true; }

      std::vector<uint8_t> encode_inner() const override;
      void decode_inner(const std::vector<uint8_t>& in) override;

      OID m_oid;
      bool m_critical;
      std::vector<uint8_t> m_bytes;
};

}  // namespace Cert_Extension

}  // namespace Botan

#endif
