Improve detection of Cloudflare WARP traffic (#2491)

See: #2484

1 files changed, 96 insertions, 0 deletions

diff --git a/src/lib/protocols/cloudflare_warp.c b/src/lib/protocols/cloudflare_warp.c
new file mode 100644
index 000000000..e14647084
--- /dev/null
+++ b/src/lib/protocols/cloudflare_warp.c
@@ -0,0 +1,96 @@
+/*
+ * cloudflare_warp.c
+ *
+ * Copyright (C) 2024 - ntop.org
+ *
+ * nDPI is free software: you can zmqtribute 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_CLOUDFLARE_WARP
+
+#include "ndpi_api.h"
+#include "ndpi_private.h"
+
+
+static void ndpi_int_cloudflare_warp_add_connection(struct ndpi_detection_module_struct * ndpi_struct,
+                                                    struct ndpi_flow_struct * flow)
+{
+  NDPI_LOG_INFO(ndpi_struct, "found CloudflareWarp\n");
+  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_CLOUDFLARE_WARP,
+                             NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
+}
+
+
+static void ndpi_search_cloudflare_warp(struct ndpi_detection_module_struct *ndpi_struct,
+                                        struct ndpi_flow_struct *flow)
+{
+  NDPI_LOG_DBG(ndpi_struct, "search CloudflareWarp\n");
+
+  /* https://developers.cloudflare.com/cloudflare-one/connections/connect-devices/warp/deployment/firewall/ */
+
+  /* Cloudflare has been using wireguard and it is moving to MASQUE:
+     * https://blog.cloudflare.com/1111-warp-better-vpn/
+     * https://blog.cloudflare.com/zero-trust-warp-with-a-masque
+
+     Wireguard. It is not a standard wireguard traffic:
+     * message type seems to be 0xc1-0xc4 instead of 1-4
+     * handshake messages are different
+     * reserved bytes are set to 0x00 only on the very first msg, i.e 0xc1
+     However:
+     * for the "data" messages, the receiver_index and counter fields seems as the standard ones
+     * the general logic (2 handshake pkts + data) seems the same
+
+     TODO: Not yet available traffic sample with MASQUE
+
+     Overall, it should be enough to identify it via ip and port matching
+  */
+
+  if(flow->guessed_protocol_id_by_ip == NDPI_PROTOCOL_CLOUDFLARE_WARP) {
+    /* Wireguard */
+    if(flow->s_port == ntohs(2408) || flow->c_port == ntohs(2408) ||
+       flow->s_port == ntohs(500) || flow->c_port == ntohs(500) ||
+       flow->s_port == ntohs(1701) || flow->c_port == ntohs(1701) ||
+       flow->s_port == ntohs(4500) || flow->c_port == ntohs(4500)) {
+      ndpi_int_cloudflare_warp_add_connection(ndpi_struct, flow);
+      return;
+    }
+    /* MASQUE */
+    /* TODO: we should check if the QUIC dissector already owns this flow, i.e
+       if this code path is ever triggered... */
+    if(flow->s_port == ntohs(443) || flow->c_port == ntohs(443) ||
+       flow->s_port == ntohs(4443) || flow->c_port == ntohs(4443) ||
+       flow->s_port == ntohs(8443) || flow->c_port == ntohs(8443) ||
+       flow->s_port == ntohs(8095) || flow->c_port == ntohs(8095)) {
+      ndpi_int_cloudflare_warp_add_connection(ndpi_struct, flow);
+      return;
+    }
+  }
+
+  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+}
+
+
+void init_cloudflare_warp_dissector(struct ndpi_detection_module_struct *ndpi_struct,
+                                    u_int32_t *id)
+{
+  ndpi_set_bitmask_protocol_detection("CloudflareWarp", ndpi_struct, *id,
+                                      NDPI_PROTOCOL_CLOUDFLARE_WARP,
+                                      ndpi_search_cloudflare_warp,
+                                      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
+                                      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
+                                      ADD_TO_DETECTION_BITMASK);
+  *id += 1;
+}