/*

 * radius_proto.c

 *

 * Copyright (C) 2012-24 - ntop.org

 *

 * nDPI is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * nDPI 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with nDPI.  If not, see <http://www.gnu.org/licenses/>.

 *

 */

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_RADIUS

#include "ndpi_api.h"

#include "ndpi_private.h"

#define RADIUS_PORT       1812

#define RADIUS_PORT_ACC     1813

#define RADIUS_PORT_ACC_ALTERNATIVE   18013

struct radius_header {

  u_int8_t code;

  u_int8_t packet_id;

  u_int16_t len;

};

static void ndpi_check_radius(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct *packet = &ndpi_struct->packet;

  // const u_int8_t *packet_payload = packet->payload;

  u_int32_t payload_len = packet->payload_packet_len;

  if((packet->udp->dest == htons(RADIUS_PORT) || packet->udp->source == htons(RADIUS_PORT) ||

      packet->udp->dest == htons(RADIUS_PORT_ACC) || packet->udp->source == htons(RADIUS_PORT_ACC) ||

      packet->udp->dest == htons(RADIUS_PORT_ACC_ALTERNATIVE) || packet->udp->source == htons(RADIUS_PORT_ACC_ALTERNATIVE))) {

    struct radius_header *h = (struct radius_header*)packet->payload;

    /* RFC2865: The minimum length is 20 and maximum length is 4096. */

    if((payload_len < 20) || (payload_len > 4096)) {

      NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

      return;

    }

    if((h->code > 0)

       && (h->code <= 13)

       && (ntohs(h->len) == payload_len)) {

      NDPI_LOG_INFO(ndpi_struct, "Found radius\n");

      ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_RADIUS, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);

      return;

    }

  }

  if(flow->packet_counter > 3)

    NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

  return;

}

static void ndpi_search_radius(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)

{

  NDPI_LOG_DBG(ndpi_struct, "search radius\n");

  ndpi_check_radius(ndpi_struct, flow);

}

void init_radius_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  register_dissector("Radius", ndpi_struct,

                     ndpi_search_radius,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,

                     1, NDPI_PROTOCOL_RADIUS);

}