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/*
* vxlan.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_VXLAN
#include "ndpi_api.h"
/* This code handles VXLAN as per RFC 7348 */
struct vxlan_header {
u_int8_t flags[4]; /* the first byte is flags, other three are reserved */
u_int8_t vni[4]; /* the first three bytes are VNI, the last byte is reserved */
};
static void ndpi_check_vxlan(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
struct ndpi_packet_struct *packet = &ndpi_struct->packet;
u_int32_t payload_len = packet->payload_packet_len;
if((packet->udp != NULL) && (payload_len >= sizeof(struct vxlan_header))) {
u_int32_t vxlan_dst_port = ntohs(4789);
u_int32_t expected_flags = 0x08; /* only one bit should be set in the first byte */
struct vxlan_header *vxlan = (struct vxlan_header *)packet->payload;
if((packet->udp->dest == vxlan_dst_port) &&
(vxlan->flags[0] == expected_flags) && (vxlan->flags[1] == 0x0) &&
(vxlan->flags[2] == 0x0) && (vxlan->flags[3] == 0x0) &&
(vxlan->vni[3] == 0x0)) {
NDPI_LOG_INFO(ndpi_struct, "found vxlan\n");
ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_VXLAN, NDPI_PROTOCOL_VXLAN, NDPI_CONFIDENCE_DPI);
return;
}
}
NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
return;
}
void ndpi_search_vxlan(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
{
NDPI_LOG_DBG(ndpi_struct, "search vxlan\n");
/* skip marked packets */
if(flow->detected_protocol_stack[0] != NDPI_PROTOCOL_VXLAN)
ndpi_check_vxlan(ndpi_struct, flow);
}
void init_vxlan_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask)
{
ndpi_set_bitmask_protocol_detection("VXLAN", ndpi_struct, detection_bitmask, *id,
NDPI_PROTOCOL_VXLAN,
ndpi_search_vxlan,
NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
SAVE_DETECTION_BITMASK_AS_UNKNOWN,
ADD_TO_DETECTION_BITMASK);
*id += 1;
}
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