1 files changed, 96 insertions, 0 deletions
diff --git a/src/lib/protocols/socks4.c b/src/lib/protocols/socks4.c
new file mode 100644
index 000000000..e89f7050c
--- /dev/null
+++ b/src/lib/protocols/socks4.c
@@ -0,0 +1,96 @@
+/*
+ * socks4.c
+ *
+ * Copyright (C) 2014 Tomasz Bujlow <tomasz@skatnet.dk>
+ *
+ * The signature is based on the Libprotoident library.
+ *
+ * This file is part of nDPI, an open source deep packet inspection
+ * library based on the OpenDPI and PACE technology by ipoque GmbH
+ *
+ * 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_SOCKS4
+static void ndpi_int_socks4_add_connection(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
+{
+  ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_SOCKS4, NDPI_REAL_PROTOCOL);
+}
+
+static void ndpi_check_socks4(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct *packet = &flow->packet;
+  u_int32_t payload_len = packet->payload_packet_len;
+
+  /* Break after 20 packets. */
+  if (flow->packet_counter > 20) {
+    NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "Exclude SOCKS4.\n");
+    NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_SOCKS4);
+    return;
+  }
+
+  /* Check if we so far detected the protocol in the request or not. */
+  if (flow->socks4_stage == 0) {
+    NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS4 stage 0: \n");
+
+    /*Octets 3 and 4 contain the port number, port 80 and 25 for now. */
+    if ((payload_len == 9) &&
+	(((packet->payload[0] == 0x04) && (packet->payload[1] == 0x01) && (packet->payload[2] == 0x00) && (packet->payload[3] == 0x50))
+	 ||
+	 ((packet->payload[0] == 0x04) && (packet->payload[1] == 0x01) && (packet->payload[2] == 0x00) && (packet->payload[3] == 0x19)))) {
+      NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "Possible SOCKS4 request detected, we will look further for the response...\n");
+
+      /* Encode the direction of the packet in the stage, so we will know when we need to look for the response packet. */
+      flow->socks4_stage = packet->packet_direction + 1;
+    }
+
+  } else {
+    NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS4 stage %u: \n", flow->socks4_stage);
+
+    /* At first check, if this is for sure a response packet (in another direction. If not, do nothing now and return. */
+    if ((flow->socks4_stage - packet->packet_direction) == 1) {
+      return;
+    }
+
+    /* This is a packet in another direction. Check if we find the proper response. */
+    if (payload_len == 0) {
+      NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "Found SOCKS4.\n");
+      ndpi_int_socks4_add_connection(ndpi_struct, flow);
+    } else {
+      NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "The reply did not seem to belong to SOCKS4, resetting the stage to 0...\n");
+      flow->socks4_stage = 0;
+    }
+
+  }
+}
+
+void ndpi_search_socks4(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct *packet = &flow->packet;
+
+  NDPI_LOG(NDPI_PROTOCOL_SOCKS4, ndpi_struct, NDPI_LOG_DEBUG, "SOCKS4 detection...\n");
+
+  /* skip marked packets */
+  if (packet->detected_protocol_stack[0] != NDPI_PROTOCOL_SOCKS4) {
+    if (packet->tcp_retransmission == 0) {
+      ndpi_check_socks4(ndpi_struct, flow);
+    }
+  }
+}
+
+#endif