432 lines
14 KiB
C++
432 lines
14 KiB
C++
/*
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* Copyright 2013-2020 Software Radio Systems Limited
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*
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* This file is part of srsLTE.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include "srsue/hdr/stack/upper/tft_packet_filter.h"
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#include "srslte/upper/ipv6.h"
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#include <linux/ip.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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namespace srsue {
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tft_packet_filter_t::tft_packet_filter_t(uint8_t eps_bearer_id_,
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uint8_t lcid_,
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const LIBLTE_MME_PACKET_FILTER_STRUCT& tft,
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srslte::log* log_) :
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eps_bearer_id(eps_bearer_id_),
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lcid(lcid_),
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id(tft.id),
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eval_precedence(tft.eval_precedence),
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active_filters(0),
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log(log_)
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{
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int idx = 0;
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uint32_t length_in_bytes = 0;
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uint32_t remaining_bits = 0;
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while (idx < tft.filter_size) {
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uint8_t filter_type = tft.filter[idx];
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idx++;
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switch (filter_type) {
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// IPv4
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case IPV4_LOCAL_ADDR_TYPE:
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active_filters |= IPV4_LOCAL_ADDR_FLAG;
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memcpy(&ipv4_local_addr, &tft.filter[idx], IPV4_ADDR_SIZE);
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idx += IPV4_ADDR_SIZE;
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memcpy(&ipv4_local_addr_mask, &tft.filter[idx], IPV4_ADDR_SIZE);
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idx += IPV4_ADDR_SIZE;
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break;
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case IPV4_REMOTE_ADDR_TYPE:
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active_filters |= IPV4_REMOTE_ADDR_FLAG;
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memcpy(&ipv4_remote_addr, &tft.filter[idx], IPV4_ADDR_SIZE);
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idx += IPV4_ADDR_SIZE;
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memcpy(&ipv4_remote_addr_mask, &tft.filter[idx], IPV4_ADDR_SIZE);
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idx += IPV4_ADDR_SIZE;
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break;
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// IPv6
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case IPV6_REMOTE_ADDR_TYPE:
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active_filters |= IPV6_REMOTE_ADDR_FLAG;
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memcpy(&ipv6_remote_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
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idx += IPV6_ADDR_SIZE;
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memcpy(&ipv6_remote_addr_mask, &tft.filter[idx], IPV6_ADDR_SIZE);
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idx += IPV6_ADDR_SIZE;
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ipv6_remote_addr_length = IPV6_ADDR_SIZE;
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break;
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case IPV6_REMOTE_ADDR_LENGTH_TYPE: // "IPv6 remote address/prefix length type"
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active_filters |= IPV6_REMOTE_ADDR_LENGTH_FLAG;
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memcpy(&ipv6_remote_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
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idx += IPV6_ADDR_SIZE;
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ipv6_remote_addr_length = tft.filter[idx++];
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// convert address length to mask:
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length_in_bytes = ipv6_remote_addr_length / 8;
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remaining_bits = ipv6_remote_addr_length % 8;
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for (uint i = 0; i < 16; i++)
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ipv6_remote_addr_mask[i] = 0;
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for (uint i = 0; i < length_in_bytes; i++)
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ipv6_remote_addr_mask[i] = 0xff;
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if (remaining_bits > 0)
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ipv6_remote_addr_mask[length_in_bytes] = 0xff - ((1 << (8 - remaining_bits)) - 1);
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break;
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case IPV6_LOCAL_ADDR_LENGTH_TYPE:
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active_filters |= IPV6_LOCAL_ADDR_LENGTH_FLAG;
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memcpy(&ipv6_local_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
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idx += IPV6_ADDR_SIZE;
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ipv6_local_addr_length = tft.filter[idx++];
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// convert address length to mask:
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length_in_bytes = ipv6_local_addr_length / 8;
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remaining_bits = ipv6_local_addr_length % 8;
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for (uint i = 0; i < 16; i++)
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ipv6_local_addr_mask[i] = 0;
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for (uint i = 0; i < length_in_bytes; i++)
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ipv6_local_addr_mask[i] = 0xff;
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if (remaining_bits > 0)
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ipv6_local_addr_mask[length_in_bytes] = 0xff - ((1 << (8 - remaining_bits)) - 1);
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break;
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// Ports
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case SINGLE_LOCAL_PORT_TYPE:
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active_filters |= SINGLE_LOCAL_PORT_FLAG;
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memcpy(&single_local_port, &tft.filter[idx], 2);
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idx += 2;
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break;
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case SINGLE_REMOTE_PORT_TYPE:
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active_filters |= SINGLE_REMOTE_PORT_FLAG;
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memcpy(&single_remote_port, &tft.filter[idx], 2);
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idx += 2;
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break;
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case LOCAL_PORT_RANGE_TYPE:
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active_filters |= LOCAL_PORT_RANGE_FLAG;
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memcpy(&local_port_range[0], &tft.filter[idx], 2);
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memcpy(&local_port_range[1], &tft.filter[idx + 2], 2);
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if (local_port_range[0] > local_port_range[1]) { // wrong order
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uint16_t t = local_port_range[0];
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local_port_range[0] = local_port_range[1];
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local_port_range[1] = t;
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}
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idx += 4;
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break;
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case REMOTE_PORT_RANGE_TYPE:
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active_filters |= REMOTE_PORT_RANGE_FLAG;
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memcpy(&remote_port_range[0], &tft.filter[idx], 2);
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memcpy(&remote_port_range[1], &tft.filter[idx + 2], 2);
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if (remote_port_range[0] > remote_port_range[1]) { // wrong order
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uint16_t t = remote_port_range[0];
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remote_port_range[0] = remote_port_range[1];
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remote_port_range[1] = t;
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}
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idx += 4;
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break;
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// Protocol/Next Header
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case PROTOCOL_ID_TYPE:
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active_filters |= PROTOCOL_ID_FLAG;
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protocol_id = tft.filter[idx++];
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break;
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// Type of service/Traffic class
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case TYPE_OF_SERVICE_TYPE:
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active_filters |= TYPE_OF_SERVICE_FLAG;
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type_of_service = tft.filter[idx++];
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type_of_service_mask = tft.filter[idx++];
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break;
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// Flow label
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case FLOW_LABEL_TYPE:
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active_filters |= FLOW_LABEL_FLAG;
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memcpy(&flow_label, &tft.filter[idx], 3);
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idx += 3;
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break;
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// IPsec security parameter
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case SECURITY_PARAMETER_INDEX_TYPE:
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active_filters |= SECURITY_PARAMETER_INDEX_FLAG;
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memcpy(&security_parameter_index, &tft.filter[idx], 4);
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idx += 4;
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break;
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default:
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log->error("ERROR: wrong type: 0x%02x\n", filter_type);
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return;
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}
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}
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}
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bool inline tft_packet_filter_t::filter_contains(uint16_t filtertype)
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{
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return (active_filters & filtertype) != 0;
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}
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/*
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* Implements packet matching against the packet filter componenets as specified in TS 24.008, section 10.5.6.12.
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*
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* This function will only return true if all the active filter components match (logical AND).
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* It will return false as soon as any of the filter components does not match.
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*
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* Note: 'active_filters' is a bitmask; bits set to '1' represent active filter components.
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*/
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bool tft_packet_filter_t::match(const srslte::unique_byte_buffer_t& pdu)
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{
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uint16_t ip_flags = IPV4_REMOTE_ADDR_FLAG | IPV4_LOCAL_ADDR_FLAG | IPV6_REMOTE_ADDR_FLAG |
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IPV6_REMOTE_ADDR_LENGTH_FLAG | IPV6_LOCAL_ADDR_LENGTH_FLAG;
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uint16_t port_flags =
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SINGLE_LOCAL_PORT_FLAG | LOCAL_PORT_RANGE_FLAG | SINGLE_REMOTE_PORT_FLAG | REMOTE_PORT_RANGE_FLAG;
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// Check if there is any active filter
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if (active_filters == 0) {
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return false;
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}
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// Match IP Header to active filters
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if (filter_contains(ip_flags) && !match_ip(pdu)) {
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return false;
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}
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// Check Protocol ID/Next Header Field
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if (filter_contains(PROTOCOL_ID_FLAG) && !match_protocol(pdu)) {
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return false;
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}
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// Check Ports/Port Range
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if (filter_contains(port_flags) && !match_port(pdu)) {
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return false;
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}
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// Check Type of Service/Traffic class
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if (filter_contains(TYPE_OF_SERVICE_FLAG) && !match_type_of_service(pdu)) {
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return false;
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}
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return true;
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}
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bool tft_packet_filter_t::match_ip(const srslte::unique_byte_buffer_t& pdu)
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{
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struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
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struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
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// It is implied, that this is always an OUTGOING packet
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if (ip_pkt->version == 4) {
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// Check match on IPv4 packet
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if (filter_contains(IPV4_LOCAL_ADDR_FLAG)) {
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if ((ip_pkt->saddr & ipv4_local_addr_mask) != (ipv4_local_addr & ipv4_local_addr_mask)) {
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return false;
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}
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}
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if (filter_contains(IPV4_REMOTE_ADDR_FLAG)) {
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if ((ip_pkt->daddr & ipv4_remote_addr_mask) != (ipv4_remote_addr & ipv4_remote_addr_mask)) {
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return false;
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}
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}
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} else if (ip_pkt->version == 6) {
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// Check match on IPv6
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if (filter_contains(IPV6_REMOTE_ADDR_FLAG | IPV6_REMOTE_ADDR_LENGTH_FLAG)) {
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bool match = true;
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for (int i = 0; i < ipv6_remote_addr_length; i++) {
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match &= ((ipv6_remote_addr[i] ^ ip6_pkt->daddr.__in6_u.__u6_addr8[i]) & ipv6_remote_addr_mask[i]) == 0;
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if (!match) {
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return false;
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}
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}
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return true;
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}
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} else {
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// Error
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return false;
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}
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return true;
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}
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bool tft_packet_filter_t::match_protocol(const srslte::unique_byte_buffer_t& pdu)
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{
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struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
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struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
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if (ip_pkt->version == 4) {
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// Check match on IPv4 packet
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if (ip_pkt->protocol != protocol_id) {
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return false;
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}
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} else if (ip_pkt->version == 6) {
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// Check match on IPv6 packet
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if (ip6_pkt->nexthdr != protocol_id) {
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return false;
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}
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} else {
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// Error
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return false;
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}
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return true;
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}
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bool tft_packet_filter_t::match_type_of_service(const srslte::unique_byte_buffer_t& pdu)
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{
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struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
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if (ip_pkt->version == 4) {
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// Check match on IPv4 packet
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if ((ip_pkt->tos ^ type_of_service) & type_of_service_mask) {
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return false;
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}
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} else if (ip_pkt->version == 6) {
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// IPv6 traffic class not supported yet
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return false;
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}
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return true;
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}
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bool tft_packet_filter_t::match_flow_label(const srslte::unique_byte_buffer_t& pdu)
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{
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struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
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if (ip6_pkt->version == 6 && (active_filters & FLOW_LABEL_FLAG)) {
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// Check match on IPv4 packet
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if (memcmp(ip6_pkt->flow_lbl, flow_label, 3) != 0) {
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return false;
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}
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}
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return true;
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}
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bool tft_packet_filter_t::match_port(const srslte::unique_byte_buffer_t& pdu)
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{
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struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
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struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
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struct udphdr* udp_pkt;
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struct tcphdr* tcp_pkt;
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if (ip_pkt->version == 4) {
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switch (ip_pkt->protocol) {
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case UDP_PROTOCOL:
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udp_pkt = (struct udphdr*)&pdu->msg[ip_pkt->ihl * 4];
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if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
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if (udp_pkt->source != single_local_port) {
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return false;
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}
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}
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if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
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if (udp_pkt->dest != single_remote_port) {
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return false;
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}
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}
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break;
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case TCP_PROTOCOL:
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tcp_pkt = (struct tcphdr*)&pdu->msg[ip_pkt->ihl * 4];
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if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
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if (tcp_pkt->source != single_local_port) {
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return false;
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}
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}
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if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
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if (tcp_pkt->dest != single_remote_port) {
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return false;
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}
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}
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break;
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default:
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return false;
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}
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} else if (ip_pkt->version == 6) {
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switch (ip6_pkt->nexthdr) {
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case UDP_PROTOCOL:
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udp_pkt = (struct udphdr*)&pdu->msg[sizeof(ipv6hdr)];
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if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
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if (udp_pkt->source != single_local_port) {
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return false;
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}
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}
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if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
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if (udp_pkt->dest != single_remote_port) {
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return false;
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}
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}
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break;
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case TCP_PROTOCOL:
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tcp_pkt = (struct tcphdr*)&pdu->msg[sizeof(ipv6hdr)];
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if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
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if (tcp_pkt->source != single_local_port) {
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return false;
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}
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}
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if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
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if (tcp_pkt->dest != single_remote_port) {
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return false;
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}
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}
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break;
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default:
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return false;
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}
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}
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return true;
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}
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uint8_t tft_pdu_matcher::check_tft_filter_match(const srslte::unique_byte_buffer_t& pdu)
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{
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std::lock_guard<std::mutex> lock(tft_mutex);
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uint8_t lcid = default_lcid;
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for (std::pair<const uint16_t, tft_packet_filter_t>& filter_pair : tft_filter_map) {
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bool match = filter_pair.second.match(pdu);
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if (match) {
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lcid = filter_pair.second.lcid;
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log->debug("Found filter match -- EPS bearer Id %d, LCID %d\n", filter_pair.second.eps_bearer_id, lcid);
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break;
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}
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}
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return lcid;
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}
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int tft_pdu_matcher::apply_traffic_flow_template(const uint8_t& erab_id,
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const uint8_t& lcid,
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const LIBLTE_MME_TRAFFIC_FLOW_TEMPLATE_STRUCT* tft)
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{
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std::lock_guard<std::mutex> lock(tft_mutex);
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switch (tft->tft_op_code) {
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case LIBLTE_MME_TFT_OPERATION_CODE_CREATE_NEW_TFT:
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for (int i = 0; i < tft->packet_filter_list_size; i++) {
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log->info("New packet filter for TFT\n");
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tft_packet_filter_t filter(erab_id, lcid, tft->packet_filter_list[i], log);
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auto it = tft_filter_map.insert(std::make_pair(filter.eval_precedence, filter));
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if (it.second == false) {
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log->error("Error inserting TFT Packet Filter\n");
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return SRSLTE_ERROR_CANT_START;
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}
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}
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break;
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default:
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log->error("Unhandled TFT OP code\n");
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return SRSLTE_ERROR_CANT_START;
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}
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return SRSLTE_SUCCESS;
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}
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void tft_pdu_matcher::set_default_lcid(const uint8_t lcid)
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{
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default_lcid = lcid;
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}
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} // namespace srsue
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