diff options
Diffstat (limited to 'src/lib/protocols/coap.c')
| -rw-r--r-- | src/lib/protocols/coap.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/src/lib/protocols/coap.c b/src/lib/protocols/coap.c new file mode 100644 index 000000000..8089c8159 --- /dev/null +++ b/src/lib/protocols/coap.c @@ -0,0 +1,110 @@ +/* + * coap.c + * + * Copyright (C) 2016 Sorin Zamfir <sorin.zamfir@yahoo.com> + * + * 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_protocols.h" +#ifdef NDPI_PROTOCOL_COAP + +/** + * Entry point when protocol is identified. + */ +static void ndpi_int_coap_add_connection (struct ndpi_detection_module_struct *ndpi_struct, + struct ndpi_flow_struct *flow) +{ + // not sure if this is accurate but coap runs on top of udp and should be connectionless + ndpi_set_detected_protocol(ndpi_struct,flow,NDPI_PROTOCOL_COAP,NDPI_PROTOCOL_UNKNOWN); + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "CoAP found.\n"); +} +/** + * Dissector function that searches CoAP headers + */ +void ndpi_search_coap (struct ndpi_detection_module_struct *ndpi_struct, + struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + if (packet->detected_protocol_stack[0] != NDPI_PROTOCOL_UNKNOWN) { + return; + } + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "CoAP detection...\n"); + // searching for request + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "====>>>> COAP header: %04x%04x%04x%04x [len: %u]\n", + packet->payload[0], packet->payload[1], packet->payload[2], packet->payload[3], packet->payload_packet_len); + // check if we have version bits + if (packet->payload_packet_len < 4) { + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Excluding Coap .. mandatory header not found!\n"); + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_COAP); + return; + } + // since this is always unsigned we could have spared the 0xF0 logical AND + // vt = version and type (version is mandatory 1; type is either 0,1,2,3 ) + u_int8_t vt = (u_int8_t) ((packet->payload[0] & 0xF0) >> 4); + if ((vt == 4) || (vt == 5) || (vt == 6) || (vt == 7)) { + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Continuing Coap detection \n"); + // search for values 9 to 15 in the token length + u_int8_t tkl = (u_int8_t) ((packet->payload[0] & 0x0F)); + if ((tkl >= 9) && (tkl <= 15)) { + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Excluding Coap .. invalid token length found!\n"); + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_COAP); + return; + } + u_int8_t class = (u_int8_t) ((packet->payload[1] & 0xE0) >> 5); + u_int8_t detail = (u_int8_t) ((packet->payload[1] & 0x1F)); + if ((class == 0) && (detail == 0) && (tkl == 0) && (packet->payload_packet_len == 4)) { + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Coap found ... empty message\n"); + ndpi_int_coap_add_connection(ndpi_struct,flow); + return; + } + if ((class == 0) && ((detail == 1) || (detail == 2 ) || (detail == 3 ) || (detail == 4 ))) { + // we should probably search for options as well and payload for deeper inspection + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Coap found ... req message\n"); + ndpi_int_coap_add_connection(ndpi_struct,flow); + return; + } + if ((class == 2) || (class == 4) || (class == 5)) { + // we should probably search for options as well and payload for deeper inspection + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Coap found ... resp message\n"); + ndpi_int_coap_add_connection(ndpi_struct,flow); + return; + } + } + NDPI_LOG(NDPI_PROTOCOL_COAP, ndpi_struct, NDPI_LOG_DEBUG, "Excluding Coap ...\n"); + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_COAP); + return; + +} +/** + * Entry point for the ndpi library + */ +void init_coap_dissector (struct ndpi_detection_module_struct *ndpi_struct, + u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask) +{ + ndpi_set_bitmask_protocol_detection ("COAP", ndpi_struct, detection_bitmask, *id, + NDPI_PROTOCOL_COAP, + ndpi_search_coap, + NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD, + SAVE_DETECTION_BITMASK_AS_UNKNOWN, ADD_TO_DETECTION_BITMASK); + *id +=1; +} + + +#endif // NDPI_PROTOCOL_COAP |