diff options
Diffstat (limited to 'src/lib/protocols/snmp_proto.c')
| -rw-r--r-- | src/lib/protocols/snmp_proto.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/lib/protocols/snmp_proto.c b/src/lib/protocols/snmp_proto.c new file mode 100644 index 000000000..759d6bae0 --- /dev/null +++ b/src/lib/protocols/snmp_proto.c @@ -0,0 +1,141 @@ +/* + * snmp.c + * + * Copyright (C) 2009-2011 by ipoque GmbH + * Copyright (C) 2011-18 - 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_protocol_ids.h" + +#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_SNMP + +#include "ndpi_api.h" + +static void ndpi_int_snmp_add_connection(struct ndpi_detection_module_struct + *ndpi_struct, struct ndpi_flow_struct *flow) +{ + ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_SNMP, NDPI_PROTOCOL_UNKNOWN); +} + +void ndpi_search_snmp(struct ndpi_detection_module_struct *ndpi_struct, struct ndpi_flow_struct *flow) +{ + struct ndpi_packet_struct *packet = &flow->packet; + + NDPI_LOG_DBG(ndpi_struct, "search SNMP\n"); + + if (packet->payload_packet_len > 32 && packet->payload[0] == 0x30) { + int offset; + u_int16_t u16; + + switch (packet->payload[1]) { + case 0x81: + offset = 3; + break; + case 0x82: + offset = 4; + break; + default: + if (packet->payload[1] > 0x82) { + NDPI_LOG_DBG2(ndpi_struct, "SNMP excluded, second byte is > 0x82\n"); + goto excl; + } + offset = 2; + } + + u16 = ntohs(get_u_int16_t(packet->payload, offset)); + + if((u16 != 0x0201) && (u16 != 0x0204)) { + NDPI_LOG_DBG2(ndpi_struct, "SNMP excluded, 0x0201/0x0204 pattern not found\n"); + goto excl; + } + + if (packet->payload[offset + 2] >= 0x04) { + NDPI_LOG_DBG2(ndpi_struct, "SNMP excluded, version > 3\n"); + goto excl; + } + + if (flow->l4.udp.snmp_stage == 0) { + if (packet->udp->dest == htons(161) || packet->udp->dest == htons(162)) { + NDPI_LOG_INFO(ndpi_struct, "found SNMP by port\n"); + ndpi_int_snmp_add_connection(ndpi_struct, flow); + return; + } + NDPI_LOG_DBG2(ndpi_struct, "SNMP stage 0\n"); + if (packet->payload[offset + 2] == 3) { + flow->l4.udp.snmp_msg_id = ntohs(get_u_int32_t(packet->payload, offset + 8)); + } else if (packet->payload[offset + 2] == 0) { + flow->l4.udp.snmp_msg_id = get_u_int8_t(packet->payload, offset + 15); + } else { + flow->l4.udp.snmp_msg_id = ntohs(get_u_int16_t(packet->payload, offset + 15)); + } + flow->l4.udp.snmp_stage = 1 + packet->packet_direction; + return; + } else if (flow->l4.udp.snmp_stage == 1 + packet->packet_direction) { + if (packet->payload[offset + 2] == 0) { + if (flow->l4.udp.snmp_msg_id != get_u_int8_t(packet->payload, offset + 15) - 1) { + NDPI_LOG_DBG2(ndpi_struct, + "SNMP v1 excluded, message ID doesn't match\n"); + goto excl; + } + } + } else if (flow->l4.udp.snmp_stage == 2 - packet->packet_direction) { + NDPI_LOG_DBG2(ndpi_struct, "SNMP stage 1-2\n"); + if (packet->payload[offset + 2] == 3) { + if (flow->l4.udp.snmp_msg_id != ntohs(get_u_int32_t(packet->payload, offset + 8))) { + NDPI_LOG_DBG2(ndpi_struct, + "SNMP v3 excluded, message ID doesn't match\n"); + goto excl; + } + } else if (packet->payload[offset + 2] == 0) { + if (flow->l4.udp.snmp_msg_id != get_u_int8_t(packet->payload, offset + 15)) { + NDPI_LOG_DBG2(ndpi_struct, + "SNMP v1 excluded, message ID doesn't match\n"); + goto excl; + } + } else { + if (flow->l4.udp.snmp_msg_id != ntohs(get_u_int16_t(packet->payload, offset + 15))) { + NDPI_LOG_DBG2(ndpi_struct, + "SNMP v2 excluded, message ID doesn't match\n"); + goto excl; + } + } + NDPI_LOG_INFO(ndpi_struct, "found SNMP\n"); + ndpi_int_snmp_add_connection(ndpi_struct, flow); + return; + } + } + excl: + NDPI_EXCLUDE_PROTO(ndpi_struct, flow); + +} + + +void init_snmp_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask) +{ + ndpi_set_bitmask_protocol_detection("SNMP", ndpi_struct, detection_bitmask, *id, + NDPI_PROTOCOL_SNMP, + ndpi_search_snmp, + NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD, + SAVE_DETECTION_BITMASK_AS_UNKNOWN, + ADD_TO_DETECTION_BITMASK); + + *id += 1; +} + |