diff options
Diffstat (limited to 'src/lib/protocols/skype.c')
| -rw-r--r-- | src/lib/protocols/skype.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/src/lib/protocols/skype.c b/src/lib/protocols/skype.c new file mode 100644 index 000000000..8d2a3a72b --- /dev/null +++ b/src/lib/protocols/skype.c @@ -0,0 +1,122 @@ +/* + * skype.c + * + * Copyright (C) 2011-15 - 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_api.h" + +#ifdef NDPI_PROTOCOL_SKYPE + + +static u_int8_t is_skype_host(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t host) { + struct in_addr pin; + + pin.s_addr = host; + + return((ndpi_network_ptree_match(ndpi_struct, &pin) == NDPI_PROTOCOL_SKYPE) ? 1 : 0); +} + +u_int8_t is_skype_flow(struct ndpi_detection_module_struct *ndpi_struct, + struct ndpi_flow_struct *flow) { + struct ndpi_packet_struct *packet = &flow->packet; + + if(packet->iph) { + /* + Skype connections are identified by some SSL-like communications + without SSL certificate being exchanged + */ + if(is_skype_host(ndpi_struct, ntohl(packet->iph->saddr)) + || is_skype_host(ndpi_struct, ntohl(packet->iph->daddr))) { + return(1); + } + } + + return(0); +} + +static void ndpi_check_skype(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + // const u_int8_t *packet_payload = packet->payload; + u_int32_t payload_len = packet->payload_packet_len; + + /* + Skype AS8220 + 212.161.8.0/24 + */ + if(is_skype_flow(ndpi_struct, flow)) { + ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_SKYPE, NDPI_REAL_PROTOCOL); + return; + } + + if(packet->udp != NULL) { + flow->l4.udp.skype_packet_id++; + + if(flow->l4.udp.skype_packet_id < 5) { + /* skype-to-skype */ + if(((payload_len == 3) && ((packet->payload[2] & 0x0F)== 0x0d)) + || ((payload_len >= 16) + && (packet->payload[0] != 0x30) /* Avoid invalid SNMP detection */ + && (packet->payload[2] == 0x02))) { + NDPI_LOG(NDPI_PROTOCOL_SKYPE, ndpi_struct, NDPI_LOG_DEBUG, "Found skype.\n"); + ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_SKYPE, NDPI_REAL_PROTOCOL); + } + + return; + } + + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_SKYPE); + return; + } else if(packet->tcp != NULL) { + flow->l4.tcp.skype_packet_id++; + + if(flow->l4.tcp.skype_packet_id < 3) { + ; /* Too early */ + } else if((flow->l4.tcp.skype_packet_id == 3) + /* We have seen the 3-way handshake */ + && flow->l4.tcp.seen_syn + && flow->l4.tcp.seen_syn_ack + && flow->l4.tcp.seen_ack) { + if((payload_len == 8) || (payload_len == 3)) { + //printf("[SKYPE] %u/%u\n", ntohs(packet->tcp->source), ntohs(packet->tcp->dest)); + + NDPI_LOG(NDPI_PROTOCOL_SKYPE, ndpi_struct, NDPI_LOG_DEBUG, "Found skype.\n"); + ndpi_int_add_connection(ndpi_struct, flow, NDPI_PROTOCOL_SKYPE, NDPI_REAL_PROTOCOL); + } + + /* printf("[SKYPE] [id: %u][len: %d]\n", flow->l4.tcp.skype_packet_id, payload_len); */ + } else + NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_SKYPE); + + return; + } +} + +void ndpi_search_skype(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + + NDPI_LOG(NDPI_PROTOCOL_SKYPE, ndpi_struct, NDPI_LOG_DEBUG, "skype detection...\n"); + + /* skip marked packets */ + if(packet->detected_protocol_stack[0] != NDPI_PROTOCOL_SKYPE) + ndpi_check_skype(ndpi_struct, flow); +} + +#endif |