ZMQ.cpp

/*
 *
 * (C) 2021-24 - ntop.org 
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include "include.h"


#ifdef HAVE_ZMQ

#define DEFAULT_ZMQ_TCP_KEEPALIVE            1  /* Keepalive ON */
#define DEFAULT_ZMQ_TCP_KEEPALIVE_IDLE       30 /* Keepalive after 30 seconds */
#define DEFAULT_ZMQ_TCP_KEEPALIVE_CNT        3  /* Keepalive send 3 probes */
#define DEFAULT_ZMQ_TCP_KEEPALIVE_INTVL      3  /* Keepalive probes sent every 3 seconds */
#define MAX_SOCKET_BUFFER_SIZE 8388608 /* 8 MB */

/* ******************************* */

ZMQ::ZMQ(const char *endpoint, const char *server_public_key) {
  context = zmq_ctx_new();

  if(context == NULL) {
    trace->traceEvent(TRACE_ERROR, "[ERROR] Unable to create ZMQ context");
    exit(1);
  }

  zmq_socket_handler = zmq_socket(context, ZMQ_PUB /* always publisher: we produce messages */);

  if(zmq_socket_handler == NULL) {
    trace->traceEvent(TRACE_ERROR, "Unable to create ZMQ socket");
    exit(1);
  }

  if(server_public_key != NULL) {
    char client_public_key[41];
    char client_secret_key[41];
    int rc;

    if(strlen(server_public_key) != 40) {
      trace->traceEvent(TRACE_ERROR, "Bad ZMQ server public key size (%lu != 40)", strlen(server_public_key));
      goto no_encrypt;
    }

    trace->traceEvent(TRACE_INFO, "Setting ZMQ server curve key to '%s'", server_public_key);

    /* (1) - Generate client keypairs */
    rc = zmq_curve_keypair(client_public_key, client_secret_key);

    if(rc != 0) {
      trace->traceEvent(TRACE_ERROR, "Error generating ZMQ client key pair");
      goto no_encrypt;
    }

    /* (2) - Enable client secret key */
    rc = zmq_setsockopt(zmq_socket_handler, ZMQ_CURVE_SECRETKEY, client_secret_key, 41);
    if(rc != 0) {
      trace->traceEvent(TRACE_ERROR, "Error setting ZMQ_CURVE_SECRETKEY = %s", client_secret_key);
      goto no_encrypt;
    }

    /* (3) - Enable client public key */
    rc = zmq_setsockopt(zmq_socket_handler, ZMQ_CURVE_PUBLICKEY, client_public_key, 41);
    if(rc != 0) {
      trace->traceEvent(TRACE_ERROR, "Error setting ZMQ_CURVE_PUBLICKEY = %s", client_public_key);
      goto no_encrypt;
    }

    /* (4) - Set the public server key generated on the server side */
    rc = zmq_setsockopt(zmq_socket_handler, ZMQ_CURVE_SERVERKEY, server_public_key, 41);
    if(rc != 0) {
      trace->traceEvent(TRACE_ERROR, "Error setting ZMQ_CURVE_SERVERKEY = %s (%d)", server_public_key, errno);
      goto no_encrypt;
    }

  no_encrypt:
    ;
  }

  if(zmq_connect(zmq_socket_handler, endpoint) != 0) {
    trace->traceEvent(TRACE_ERROR, "Unable to connect to ZMQ endpoint %s [%s]", endpoint, strerror(errno));
    throw "ZMQ connect error";
  }
};

/* ******************************* */

ZMQ::~ZMQ() {
  zmq_close(zmq_socket_handler);
  zmq_ctx_destroy(context);
};

/* ******************************* */

void ZMQ::sendMessage(const char *topic, const char *msg) {
  struct zmq_msg_hdr msg_hdr;
  u_int len = strlen(msg);

  memset(&msg_hdr, 0, sizeof(msg_hdr));
  snprintf(msg_hdr.url, sizeof(msg_hdr.url), "%s", topic);
  msg_hdr.source_id = 999, msg_hdr.version = ZMQ_MSG_VERSION, msg_hdr.size = len;

  if(zmq_send(zmq_socket_handler, &msg_hdr, sizeof(msg_hdr), ZMQ_SNDMORE) != sizeof(msg_hdr))
    trace->traceEvent(TRACE_WARNING, "ZMQ send errror");

  if(zmq_send(zmq_socket_handler, msg, msg_hdr.size, 0) != msg_hdr.size)
    trace->traceEvent(TRACE_WARNING, "ZMQ send errror");
  else
    trace->traceEvent(TRACE_INFO, "Sent [topic: %s][msg: %s]", msg_hdr.url, msg);
}

/* ******************************* */

#endif /* HAVE_ZMQ */