mechanism.hpp

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/* 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