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/*
* netflow.c
*
* Copyright (C) 2011-15 - 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_api.h"
#ifdef NDPI_PROTOCOL_NETFLOW
#ifndef __KERNEL__
#ifdef WIN32
extern int gettimeofday(struct timeval * tp, struct timezone * tzp);
#endif
#define do_gettimeofday(a) gettimeofday(a, NULL)
#endif
static void ndpi_check_netflow(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &flow->packet;
// const u_int8_t *packet_payload = packet->payload;
u_int32_t payload_len = packet->payload_packet_len;
time_t now;
struct timeval now_tv;
if((packet->udp != NULL) && (payload_len >= 24)) {
u_int16_t version = (packet->payload[0] << 8) + packet->payload[1], uptime_offset;
u_int32_t when, *_when;
u_int16_t n = (packet->payload[2] << 8) + packet->payload[3];
switch(version) {
case 1:
case 5:
case 7:
case 9:
{
u_int16_t num_flows = n;
if((num_flows == 0) || (num_flows > 30))
return;
}
uptime_offset = 8;
break;
case 10: /* IPFIX */
{
u_int16_t ipfix_len = n;
if(ipfix_len != payload_len)
return;
}
uptime_offset = 4;
break;
default:
return;
}
_when = (u_int32_t*)&packet->payload[uptime_offset]; /* Sysuptime */
when = ntohl(*_when);
do_gettimeofday(&now_tv);
now = now_tv.tv_sec;
if(((version == 1) && (when == 0))
|| ((when >= 946684800 /* 1/1/2000 */) && (when <= now))) {
NDPI_LOG(NDPI_PROTOCOL_NETFLOW, ndpi_struct, NDPI_LOG_DEBUG, "Found netflow.\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_NETFLOW, NDPI_PROTOCOL_UNKNOWN);
return;
}
}
}
void ndpi_search_netflow(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
NDPI_LOG(NDPI_PROTOCOL_NETFLOW, ndpi_struct, NDPI_LOG_DEBUG, "netflow detection...\n");
ndpi_check_netflow(ndpi_struct, flow);
}
void init_netflow_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
ndpi_set_bitmask_protocol_detection("NetFlow", ndpi_struct, detection_bitmask, *id,
NDPI_PROTOCOL_NETFLOW,
ndpi_search_netflow,
NDPI_SELECTION_BITMASK_PROTOCOL_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}
#endif
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