mechanism.hpp

/* SPDX-License-Identifier: MPL-2.0 */

#ifndef __ZMQ_MECHANISM_HPP_INCLUDED__
#define __ZMQ_MECHANISM_HPP_INCLUDED__

#include "stdint.hpp"
#include "options.hpp"
#include "blob.hpp"
#include "metadata.hpp"

namespace zmq
{
class msg_t;
class session_base_t;

//  Abstract class representing security mechanism.
//  Different mechanism extends this class.

class mechanism_t
{
  public:
    enum status_t
    {
        handshaking,
        ready,
        error
    };

    mechanism_t (const options_t &options_);

    virtual ~mechanism_t ();

    //  Prepare next handshake command that is to be sent to the peer.
    virtual int next_handshake_command (msg_t *msg_) = 0;

    //  Process the handshake command received from the peer.
    virtual int process_handshake_command (msg_t *msg_) = 0;

    virtual int encode (msg_t *) { return 0; }

    virtual int decode (msg_t *) { return 0; }

    //  Notifies mechanism about availability of ZAP message.
    virtual int zap_msg_available () { return 0; }

    //  Returns the status of this mechanism.
    virtual status_t status () const = 0;

    void set_peer_routing_id (const void *id_ptr_, size_t id_size_);

    void peer_routing_id (msg_t *msg_);

    void set_user_id (const void *user_id_, size_t size_);

    const blob_t &get_user_id () const;

    const metadata_t::dict_t &get_zmtp_properties () const
    {
        return _zmtp_properties;
    }

    const metadata_t::dict_t &get_zap_properties () const
    {
        return _zap_properties;
    }

  protected:
    //  Only used to identify the socket for the Socket-Type
    //  property in the wire protocol.
    static const char *socket_type_string (int socket_type_);

    static size_t add_property (unsigned char *ptr_,
                                size_t ptr_capacity_,
                                const char *name_,
                                const void *value_,
                                size_t value_len_);
    static size_t property_len (const char *name_, size_t value_len_);

    size_t add_basic_properties (unsigned char *ptr_,
                                 size_t ptr_capacity_) const;
    size_t basic_properties_len () const;

    void make_command_with_basic_properties (msg_t *msg_,
                                             const char *prefix_,
                                             size_t prefix_len_) const;

    //  Parses a metadata.
    //  Metadata consists of a list of properties consisting of
    //  name and value as size-specified strings.
    //  Returns 0 on success and -1 on error, in which case errno is set.
    int parse_metadata (const unsigned char *ptr_,
                        size_t length_,
                        bool zap_flag_ = false);

    //  This is called by parse_property method whenever it
    //  parses a new property. The function should return 0
    //  on success and -1 on error, in which case it should
    //  set errno. Signaling error prevents parser from
    //  parsing remaining data.
    //  Derived classes are supposed to override this
    //  method to handle custom processing.
    virtual int
    property (const std::string &name_, const void *value_, size_t length_);

    const options_t options;

  private:
    //  Properties received from ZMTP peer.
    metadata_t::dict_t _zmtp_properties;

    //  Properties received from ZAP server.
    metadata_t::dict_t _zap_properties;

    blob_t _routing_id;

    blob_t _user_id;

    //  Returns true iff socket associated with the mechanism
    //  is compatible with a given socket type 'type_'.
    bool check_socket_type (const char *type_, size_t len_) const;
};
}

#endif