/*
* Policies
* (C) 2004-2006 Jack Lloyd
*
* Released under the terms of the Botan license
*/

#ifndef BOTAN_TLS_POLICY_H__
#define BOTAN_TLS_POLICY_H__

#include <botan/tls_version.h>
#include <botan/x509cert.h>
#include <botan/dl_group.h>
#include <vector>

namespace Botan {

namespace TLS {

/**
* TLS Policy Base Class
* Inherit and overload as desired to suit local policy concerns
*/
class BOTAN_DLL Policy
   {
   public:

      /**
      * Returns a list of ciphers we are willing to negotiate, in
      * order of preference. Allowed values: any block cipher name, or
      * ARC4.
      */
      virtual std::vector<std::string> allowed_ciphers() const;

      /**
      * Returns a list of hash algorithms we are willing to use for
      * signatures.
      */
      virtual std::vector<std::string> allowed_signature_hashes() const;

      /**
      * Returns a list of MAC algorithms we are willing to use.
      */
      virtual std::vector<std::string> allowed_macs() const;

      /**
      * Returns a list of key exchange algorithms we are willing to
      * use, in order of preference. Allowed values: DH, empty string
      * (representing RSA using server certificate key)
      */
      virtual std::vector<std::string> allowed_key_exchange_methods() const;

      /**
      * Returns a list of signature algorithms we are willing to
      * use, in order of preference. Allowed values RSA and DSA.
      */
      virtual std::vector<std::string> allowed_signature_methods() const;

      /**
      * Return list of ECC curves we are willing to use in order of preference
      */
      virtual std::vector<std::string> allowed_ecc_curves() const;

      /**
      * Returns a list of signature algorithms we are willing to use,
      * in order of preference. Allowed values any value of
      * Compression_Method.
      */
      virtual std::vector<byte> compression() const;

      /**
      * Choose an elliptic curve to use
      */
      virtual std::string choose_curve(const std::vector<std::string>& curve_names) const;

      /**
      * Allow renegotiation even if the counterparty doesn't
      * support the secure renegotiation extension.
      *
      * @warning Changing this to true exposes you to injected
      * plaintext attacks. Read RFC 5746 for background.
      */
      virtual bool allow_insecure_renegotiation() const { return false; }

      /**
      * Return the group to use for ephemeral Diffie-Hellman key agreement
      */
      virtual DL_Group dh_group() const;

      /**
      * Return the minimum DH group size we're willing to use
      */
      virtual size_t minimum_dh_group_size() const;

      /**
      * If this function returns false, unknown SRP/PSK identifiers
      * will be rejected with an unknown_psk_identifier alert as soon
      * as the non-existence is identified. Otherwise, a false
      * identifier value will be used and the protocol allowed to
      * proceed, causing the handshake to eventually fail without
      * revealing that the username does not exist on this system.
      */
      virtual bool hide_unknown_users() const { return false; }

      /**
      * Return the allowed lifetime of a session ticket. If 0, session
      * tickets do not expire until the session ticket key rolls over.
      * Expired session tickets cannot be used to resume a session.
      */
      virtual u32bit session_ticket_lifetime() const;

      /**
      * @return true if and only if we are willing to accept this version
      */
      virtual bool acceptable_protocol_version(const Protocol_Version& version) const;

      /**
      * @return the version we would prefer to negotiate
      */
      virtual Protocol_Version pref_version() const;

      virtual ~Policy() {}
   };

/**
* Return allowed ciphersuites, in order of preference
*/
std::vector<u16bit> ciphersuite_list(const Policy& policy,
                                     Protocol_Version version,
                                     bool have_srp);

}

}

#endif