/*

 * git.c

 *

 * Copyright (C) 2012-22 - ntop.org

 *

 * This module 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.

 *

 * This module 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.

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

 *

 */

#include "ndpi_protocol_ids.h"

#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_GIT

#include "ndpi_api.h"

#include "ndpi_private.h"

#define GIT_PORT 9418

static void ndpi_search_git(struct ndpi_detection_module_struct *ndpi_struct,

          struct ndpi_flow_struct *flow)

{

  struct ndpi_packet_struct * packet = &ndpi_struct->packet;

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

  if((packet->tcp != NULL) && (packet->payload_packet_len > 4)) {

    if((ntohs(packet->tcp->source) == GIT_PORT)

       || (ntohs(packet->tcp->dest) == GIT_PORT)) {

      const u_int8_t * pp = packet->payload;

      u_int16_t payload_len = packet->payload_packet_len;  

      u_int8_t found_git = 1;

      u_int16_t offset = 0;

      while((offset+4) < payload_len) {

  char len[5];

  u_int32_t git_pkt_len;

  memcpy(&len, &pp[offset], 4), len[4] = 0;

  if(sscanf(len, "%x", &git_pkt_len) != 1) {

    found_git = 0;

    break;

  }

  if((payload_len < git_pkt_len) || (git_pkt_len == 0 /* Bad */)) {

    found_git = 0;

    break;

  } else

    offset += git_pkt_len, payload_len -= git_pkt_len;      

      }

      if(found_git) {

  NDPI_LOG_INFO(ndpi_struct, "found Git\n");

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

  return;

      }

    }

  }

  NDPI_EXCLUDE_DISSECTOR(ndpi_struct, flow);

}

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

void init_git_dissector(struct ndpi_detection_module_struct *ndpi_struct)

{

  register_dissector("Git", ndpi_struct,

                     ndpi_search_git,

                     NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,

                     1, NDPI_PROTOCOL_GIT);

}