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Diffstat (limited to 'src/lib/protocols/mdns.c')
| -rw-r--r-- | src/lib/protocols/mdns.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/src/lib/protocols/mdns.c b/src/lib/protocols/mdns.c new file mode 100644 index 000000000..9b9b72582 --- /dev/null +++ b/src/lib/protocols/mdns.c @@ -0,0 +1,146 @@ +/* + * mdns.c + * + * Copyright (C) 2009-2011 by ipoque GmbH + * Copyright (C) 2011-15 - ntop.org + * + * 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_MDNS + +#define NDPI_MAX_MDNS_REQUESTS 128 + +/* +This module should detect MDNS +*/ + +static void ndpi_int_mdns_add_connection(struct ndpi_detection_module_struct + *ndpi_struct, struct ndpi_flow_struct *flow) +{ + ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_MDNS, NDPI_REAL_PROTOCOL); +} + +static int ndpi_int_check_mdns_payload(struct ndpi_detection_module_struct + *ndpi_struct, struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + + if ((packet->payload[2] & 0x80) == 0 && + ntohs(get_u_int16_t(packet->payload, 4)) <= NDPI_MAX_MDNS_REQUESTS && + ntohs(get_u_int16_t(packet->payload, 6)) <= NDPI_MAX_MDNS_REQUESTS) { + + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, NDPI_LOG_DEBUG, "found MDNS with question query.\n"); + + return 1; + } else if ((packet->payload[2] & 0x80) != 0 && + ntohs(get_u_int16_t(packet->payload, 4)) == 0 && + ntohs(get_u_int16_t(packet->payload, 6)) <= NDPI_MAX_MDNS_REQUESTS && + ntohs(get_u_int16_t(packet->payload, 6)) != 0) { + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, NDPI_LOG_DEBUG, "found MDNS with answer query.\n"); + + return 1; + } + + return 0; +} + +void ndpi_search_mdns(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + +// struct ndpi_id_struct *src=ndpi_struct->src; +// struct ndpi_id_struct *dst=ndpi_struct->dst; + + u_int16_t dport; +// const u_int16_t sport=ntohs(packet->udp->source); + + /* check if UDP and */ + if (packet->udp != NULL) { + /*read destination port */ + dport = ntohs(packet->udp->dest); + + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, NDPI_LOG_DEBUG, "MDNS udp start \n"); + + + + /*check standard MDNS to port 5353 */ + /*took this information from http://www.it-administrator.de/lexikon/multicast-dns.html */ + + if (dport == 5353 && packet->payload_packet_len >= 12) { + + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, NDPI_LOG_DEBUG, "found MDNS with destination port 5353\n"); + + /* MDNS header is similar to dns header */ + /* dns header + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | ID | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + |QR| Opcode |AA|TC|RD|RA| Z | RCODE | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | QDCOUNT | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | ANCOUNT | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | NSCOUNT | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + | ARCOUNT | + +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ + * + * dns query check: query: QR set, ancount = 0, nscount = 0, QDCOUNT < MAX_MDNS, ARCOUNT < MAX_MDNS + * + */ + + /* mdns protocol must have destination address 224.0.0.251 */ + /* took this information from http://www.it-administrator.de/lexikon/multicast-dns.html */ + + if (packet->iph != NULL && ntohl(packet->iph->daddr) == 0xe00000fb) { + + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, + NDPI_LOG_DEBUG, "found MDNS with destination address 224.0.0.251 (=0xe00000fb)\n"); + + if (ndpi_int_check_mdns_payload(ndpi_struct, flow) == 1) { + ndpi_int_mdns_add_connection(ndpi_struct, flow); + return; + } + } +#ifdef NDPI_DETECTION_SUPPORT_IPV6 + if (packet->iphv6 != NULL) { + const u_int32_t *daddr = packet->iphv6->daddr.ndpi_v6_u.u6_addr32; + if (daddr[0] == htonl(0xff020000) && daddr[1] == 0 && daddr[2] == 0 && daddr[3] == htonl(0xfb)) { + + NDPI_LOG(NDPI_PROTOCOL_MDNS, ndpi_struct, + NDPI_LOG_DEBUG, "found MDNS with destination address ff02::fb\n"); + + if (ndpi_int_check_mdns_payload(ndpi_struct, flow) == 1) { + ndpi_int_mdns_add_connection(ndpi_struct, flow); + return; + } + } + } +#endif + + } + } + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_MDNS); +} +#endif |