Added VXLAN dissector (#1439)

* RFC 7348

1 files changed, 79 insertions, 0 deletions

diff --git a/src/lib/protocols/vxlan.c b/src/lib/protocols/vxlan.c
new file mode 100644
index 000000000..9a04435bb
--- /dev/null
+++ b/src/lib/protocols/vxlan.c
@@ -0,0 +1,79 @@
+/*
+ * 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;
+}