null_mechanism.cpp

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

#include "precompiled.hpp"

#include <stddef.h>
#include <string.h>
#include <stdlib.h>

#include "err.hpp"
#include "msg.hpp"
#include "session_base.hpp"
#include "null_mechanism.hpp"

const char error_command_name[] = "\5ERROR";
const size_t error_command_name_len = sizeof (error_command_name) - 1;
const size_t error_reason_len_size = 1;

const char ready_command_name[] = "\5READY";
const size_t ready_command_name_len = sizeof (ready_command_name) - 1;

zmq::null_mechanism_t::null_mechanism_t (session_base_t *session_,
                                         const std::string &peer_address_,
                                         const options_t &options_) :
    mechanism_base_t (session_, options_),
    zap_client_t (session_, peer_address_, options_),
    _ready_command_sent (false),
    _error_command_sent (false),
    _ready_command_received (false),
    _error_command_received (false),
    _zap_request_sent (false),
    _zap_reply_received (false)
{
}

zmq::null_mechanism_t::~null_mechanism_t ()
{
}

int zmq::null_mechanism_t::next_handshake_command (msg_t *msg_)
{
    if (_ready_command_sent || _error_command_sent) {
        errno = EAGAIN;
        return -1;
    }

    if (zap_required () && !_zap_reply_received) {
        if (_zap_request_sent) {
            errno = EAGAIN;
            return -1;
        }
        //  Given this is a backward-incompatible change, it's behind a socket
        //  option disabled by default.
        int rc = session->zap_connect ();
        if (rc == -1 && options.zap_enforce_domain) {
            session->get_socket ()->event_handshake_failed_no_detail (
              session->get_endpoint (), EFAULT);
            return -1;
        }
        if (rc == 0) {
            send_zap_request ();
            _zap_request_sent = true;

            //  TODO actually, it is quite unlikely that we can read the ZAP
            //  reply already, but removing this has some strange side-effect
            //  (probably because the pipe's in_active flag is true until a read
            //  is attempted)
            rc = receive_and_process_zap_reply ();
            if (rc != 0)
                return -1;

            _zap_reply_received = true;
        }
    }

    if (_zap_reply_received && status_code != "200") {
        _error_command_sent = true;
        if (status_code != "300") {
            const size_t status_code_len = 3;
            const int rc = msg_->init_size (
              error_command_name_len + error_reason_len_size + status_code_len);
            zmq_assert (rc == 0);
            unsigned char *msg_data =
              static_cast<unsigned char *> (msg_->data ());
            memcpy (msg_data, error_command_name, error_command_name_len);
            msg_data += error_command_name_len;
            *msg_data = status_code_len;
            msg_data += error_reason_len_size;
            memcpy (msg_data, status_code.c_str (), status_code_len);
            return 0;
        }
        errno = EAGAIN;
        return -1;
    }

    make_command_with_basic_properties (msg_, ready_command_name,
                                        ready_command_name_len);

    _ready_command_sent = true;

    return 0;
}

int zmq::null_mechanism_t::process_handshake_command (msg_t *msg_)
{
    if (_ready_command_received || _error_command_received) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZMTP_UNEXPECTED_COMMAND);
        errno = EPROTO;
        return -1;
    }

    const unsigned char *cmd_data =
      static_cast<unsigned char *> (msg_->data ());
    const size_t data_size = msg_->size ();

    int rc = 0;
    if (data_size >= ready_command_name_len
        && !memcmp (cmd_data, ready_command_name, ready_command_name_len))
        rc = process_ready_command (cmd_data, data_size);
    else if (data_size >= error_command_name_len
             && !memcmp (cmd_data, error_command_name, error_command_name_len))
        rc = process_error_command (cmd_data, data_size);
    else {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (), ZMQ_PROTOCOL_ERROR_ZMTP_UNEXPECTED_COMMAND);
        errno = EPROTO;
        rc = -1;
    }

    if (rc == 0) {
        rc = msg_->close ();
        errno_assert (rc == 0);
        rc = msg_->init ();
        errno_assert (rc == 0);
    }
    return rc;
}

int zmq::null_mechanism_t::process_ready_command (
  const unsigned char *cmd_data_, size_t data_size_)
{
    _ready_command_received = true;
    return parse_metadata (cmd_data_ + ready_command_name_len,
                           data_size_ - ready_command_name_len);
}

int zmq::null_mechanism_t::process_error_command (
  const unsigned char *cmd_data_, size_t data_size_)
{
    const size_t fixed_prefix_size =
      error_command_name_len + error_reason_len_size;
    if (data_size_ < fixed_prefix_size) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (),
          ZMQ_PROTOCOL_ERROR_ZMTP_MALFORMED_COMMAND_ERROR);

        errno = EPROTO;
        return -1;
    }
    const size_t error_reason_len =
      static_cast<size_t> (cmd_data_[error_command_name_len]);
    if (error_reason_len > data_size_ - fixed_prefix_size) {
        session->get_socket ()->event_handshake_failed_protocol (
          session->get_endpoint (),
          ZMQ_PROTOCOL_ERROR_ZMTP_MALFORMED_COMMAND_ERROR);

        errno = EPROTO;
        return -1;
    }
    const char *error_reason =
      reinterpret_cast<const char *> (cmd_data_) + fixed_prefix_size;
    handle_error_reason (error_reason, error_reason_len);
    _error_command_received = true;
    return 0;
}

int zmq::null_mechanism_t::zap_msg_available ()
{
    if (_zap_reply_received) {
        errno = EFSM;
        return -1;
    }
    const int rc = receive_and_process_zap_reply ();
    if (rc == 0)
        _zap_reply_received = true;
    return rc == -1 ? -1 : 0;
}

zmq::mechanism_t::status_t zmq::null_mechanism_t::status () const
{
    if (_ready_command_sent && _ready_command_received)
        return ready;

    const bool command_sent = _ready_command_sent || _error_command_sent;
    const bool command_received =
      _ready_command_received || _error_command_received;
    return command_sent && command_received ? error : handshaking;
}

void zmq::null_mechanism_t::send_zap_request ()
{
    zap_client_t::send_zap_request ("NULL", 4, NULL, NULL, 0);
}