/*
* netflow.c
*
* Copyright (C) 2011-22 - 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_NETFLOW
#include "ndpi_api.h"
#include "ndpi_private.h"
#ifdef WIN32
extern int gettimeofday(struct timeval * tp, struct timezone * tzp);
#endif
#define do_gettimeofday(a) gettimeofday(a, NULL)
struct flow_ver1_rec {
u_int32_t srcaddr; /* Source IP Address */
u_int32_t dstaddr; /* Destination IP Address */
u_int32_t nexthop; /* Next hop router's IP Address */
u_int16_t input; /* Input interface index */
u_int16_t output; /* Output interface index */
u_int32_t dPkts; /* Packets sent in Duration */
u_int32_t dOctets; /* Octets sent in Duration */
u_int32_t first; /* SysUptime at start of flow */
u_int32_t last; /* and of last packet of the flow */
u_int16_t srcport; /* TCP/UDP source port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int16_t dstport; /* TCP/UDP destination port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int16_t pad; /* pad to word boundary */
u_int8_t proto; /* IP protocol, e.g., 6=TCP, 17=UDP, etc... */
u_int8_t tos; /* IP Type-of-Service */
u_int8_t pad2[7]; /* pad to word boundary */
};
struct flow_ver5_rec {
u_int32_t srcaddr; /* Source IP Address */
u_int32_t dstaddr; /* Destination IP Address */
u_int32_t nexthop; /* Next hop router's IP Address */
u_int16_t input; /* Input interface index */
u_int16_t output; /* Output interface index */
u_int32_t dPkts; /* Packets sent in Duration (milliseconds between 1st
& last packet in this flow)*/
u_int32_t dOctets; /* Octets sent in Duration (milliseconds between 1st
& last packet in this flow)*/
u_int32_t first; /* SysUptime at start of flow */
u_int32_t last; /* and of last packet of the flow */
u_int16_t srcport; /* TCP/UDP source port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int16_t dstport; /* TCP/UDP destination port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int8_t pad1; /* pad to word boundary */
u_int8_t tcp_flags; /* Cumulative OR of tcp flags */
u_int8_t proto; /* IP protocol, e.g., 6=TCP, 17=UDP, etc... */
u_int8_t tos; /* IP Type-of-Service */
u_int16_t src_as; /* source peer/origin Autonomous System */
u_int16_t dst_as; /* dst peer/origin Autonomous System */
u_int8_t src_mask; /* source route's mask bits */
u_int8_t dst_mask; /* destination route's mask bits */
u_int16_t pad2; /* pad to word boundary */
};
struct flow_ver7_rec {
u_int32_t srcaddr; /* Source IP Address */
u_int32_t dstaddr; /* Destination IP Address */
u_int32_t nexthop; /* Next hop router's IP Address */
u_int16_t input; /* Input interface index */
u_int16_t output; /* Output interface index */
u_int32_t dPkts; /* Packets sent in Duration */
u_int32_t dOctets; /* Octets sent in Duration */
u_int32_t first; /* SysUptime at start of flow */
u_int32_t last; /* and of last packet of the flow */
u_int16_t srcport; /* TCP/UDP source port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int16_t dstport; /* TCP/UDP destination port number (.e.g, FTP, Telnet, etc.,or equivalent) */
u_int8_t flags; /* Shortcut mode(dest only,src only,full flows*/
u_int8_t tcp_flags; /* Cumulative OR of tcp flags */
u_int8_t proto; /* IP protocol, e.g., 6=TCP, 17=UDP, etc... */
u_int8_t tos; /* IP Type-of-Service */
u_int16_t dst_as; /* dst peer/origin Autonomous System */
u_int16_t src_as; /* source peer/origin Autonomous System */
u_int8_t dst_mask; /* destination route's mask bits */
u_int8_t src_mask; /* source route's mask bits */
u_int16_t pad2; /* pad to word boundary */
u_int32_t router_sc; /* Router which is shortcut by switch */
};
static void ndpi_search_netflow(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;
time_t now;
struct timeval now_tv;
NDPI_LOG_DBG(ndpi_struct, "search netflow\n");
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], expected_len = 0;
switch(version) {
case 1:
case 5:
case 7:
case 9:
if((n == 0) || (n > 30)) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
switch(version) {
case 1:
expected_len = n * sizeof(struct flow_ver1_rec) + 16 /* header */;
break;
case 5:
expected_len = n * sizeof(struct flow_ver5_rec) + 24 /* header */;
break;
case 7:
expected_len = n * sizeof(struct flow_ver7_rec) + 24 /* header */;
break;
case 9:
/* We need to check the template */
break;
}
if((expected_len > 0) && (expected_len != payload_len)) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
uptime_offset = 8;
break;
case 10: /* IPFIX */
{
u_int16_t ipfix_len = n;
if(ipfix_len != payload_len) {
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
}
uptime_offset = 4;
break;
default:
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
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 <= (u_int32_t)now))) {
NDPI_LOG_INFO(ndpi_struct, "found netflow\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_NETFLOW, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
return;
}
} else
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
}
void init_netflow_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
{
ndpi_set_bitmask_protocol_detection("NetFlow", ndpi_struct, *id,
NDPI_PROTOCOL_NETFLOW,
ndpi_search_netflow,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}