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tf_packet_filter: Improve support for the different filter types

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master
Sylvain Munaut 5 years ago committed by Andre Puschmann
parent 2890bd07ea
commit 5783c01cbb
2 changed files with 165 additions and 23 deletions
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8
srsue/hdr/stack/upper/tft_packet_filter.h
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@ -73,16 +73,22 @@ public:
const LIBLTE_MME_PACKET_FILTER_STRUCT& tft_, const LIBLTE_MME_PACKET_FILTER_STRUCT& tft_,
srslte::log* log_); srslte::log* log_);
bool match(const srslte::unique_byte_buffer_t& pdu); bool match(const srslte::unique_byte_buffer_t& pdu);
bool filter_contains(uint16_t filtertype);
uint8_t eps_bearer_id; uint8_t eps_bearer_id;
uint8_t lcid; uint8_t lcid;
uint8_t id; uint8_t id;
uint8_t eval_precedence; uint8_t eval_precedence;
uint16_t active_filters; uint32_t active_filters;
uint32_t ipv4_remote_addr; uint32_t ipv4_remote_addr;
uint32_t ipv4_remote_addr_mask;
uint32_t ipv4_local_addr; uint32_t ipv4_local_addr;
uint32_t ipv4_local_addr_mask;
uint8_t ipv6_remote_addr[16]; uint8_t ipv6_remote_addr[16];
uint8_t ipv6_remote_addr_mask[16];
uint8_t ipv6_remote_addr_length; uint8_t ipv6_remote_addr_length;
uint8_t ipv6_local_addr[16];
uint8_t ipv6_local_addr_mask[16];
uint8_t ipv6_local_addr_length; uint8_t ipv6_local_addr_length;
uint8_t protocol_id; uint8_t protocol_id;
uint16_t single_local_port; uint16_t single_local_port;

180
srsue/src/stack/upper/tft_packet_filter.cc
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@ -22,6 +22,7 @@
#include "srsue/hdr/stack/upper/tft_packet_filter.h" #include "srsue/hdr/stack/upper/tft_packet_filter.h"
#include "srslte/upper/ipv6.h" #include "srslte/upper/ipv6.h"
#include <linux/ip.h> #include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h> #include <linux/udp.h>
namespace srsue { namespace srsue {
@ -38,66 +39,147 @@ tft_packet_filter_t::tft_packet_filter_t(uint8_t
log(log_) log(log_)
{ {
int idx = 0; int idx = 0;
uint32_t length_in_bytes = 0;
uint32_t remaining_bits = 0;
while (idx < tft.filter_size) { while (idx < tft.filter_size) {
uint8_t filter_type = tft.filter[idx]; uint8_t filter_type = tft.filter[idx];
idx++; idx++;
switch (filter_type) { switch (filter_type) {
// IPv4 // IPv4
case IPV4_LOCAL_ADDR_TYPE: case IPV4_LOCAL_ADDR_TYPE:
active_filters = IPV4_LOCAL_ADDR_FLAG; active_filters |= IPV4_LOCAL_ADDR_FLAG;
memcpy(&ipv4_local_addr, &tft.filter[idx], IPV4_ADDR_SIZE); memcpy(&ipv4_local_addr, &tft.filter[idx], IPV4_ADDR_SIZE);
idx += IPV4_ADDR_SIZE; idx += IPV4_ADDR_SIZE;
memcpy(&ipv4_local_addr_mask, &tft.filter[idx], IPV4_ADDR_SIZE);
idx += IPV4_ADDR_SIZE;
break; break;
case IPV4_REMOTE_ADDR_TYPE: case IPV4_REMOTE_ADDR_TYPE:
active_filters = IPV4_REMOTE_ADDR_FLAG; active_filters |= IPV4_REMOTE_ADDR_FLAG;
memcpy(&ipv4_remote_addr, &tft.filter[idx], IPV4_ADDR_SIZE); memcpy(&ipv4_remote_addr, &tft.filter[idx], IPV4_ADDR_SIZE);
idx += IPV4_ADDR_SIZE; idx += IPV4_ADDR_SIZE;
memcpy(&ipv4_remote_addr_mask, &tft.filter[idx], IPV4_ADDR_SIZE);
idx += IPV4_ADDR_SIZE;
break; break;
// IPv6 // IPv6
case IPV6_REMOTE_ADDR_TYPE: case IPV6_REMOTE_ADDR_TYPE:
active_filters |= IPV6_REMOTE_ADDR_FLAG;
memcpy(&ipv6_remote_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
idx += IPV6_ADDR_SIZE;
memcpy(&ipv6_remote_addr_mask, &tft.filter[idx], IPV6_ADDR_SIZE);
idx += IPV6_ADDR_SIZE;
ipv6_remote_addr_length = IPV6_ADDR_SIZE;
break; break;
case IPV6_REMOTE_ADDR_LENGTH_TYPE:
case IPV6_REMOTE_ADDR_LENGTH_TYPE: // "IPv6 remote address/prefix length type"
active_filters |= IPV6_REMOTE_ADDR_LENGTH_FLAG;
memcpy(&ipv6_remote_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
idx += IPV6_ADDR_SIZE;
ipv6_remote_addr_length = tft.filter[idx++];
// convert address length to mask:
length_in_bytes = ipv6_remote_addr_length / 8;
remaining_bits = ipv6_remote_addr_length % 8;
for (uint i = 0; i < 16; i++)
ipv6_remote_addr_mask[i] = 0;
for (uint i = 0; i < length_in_bytes; i++)
ipv6_remote_addr_mask[i] = 0xff;
if (remaining_bits > 0)
ipv6_remote_addr_mask[length_in_bytes] = 0xff - ((1 << (8 - remaining_bits)) - 1);
break; break;
case IPV6_LOCAL_ADDR_LENGTH_TYPE: case IPV6_LOCAL_ADDR_LENGTH_TYPE:
active_filters |= IPV6_LOCAL_ADDR_LENGTH_FLAG;
memcpy(&ipv6_local_addr, &tft.filter[idx], IPV6_ADDR_SIZE);
idx += IPV6_ADDR_SIZE;
ipv6_local_addr_length = tft.filter[idx++];
// convert address length to mask:
length_in_bytes = ipv6_local_addr_length / 8;
remaining_bits = ipv6_local_addr_length % 8;
for (uint i = 0; i < 16; i++)
ipv6_local_addr_mask[i] = 0;
for (uint i = 0; i < length_in_bytes; i++)
ipv6_local_addr_mask[i] = 0xff;
if (remaining_bits > 0)
ipv6_local_addr_mask[length_in_bytes] = 0xff - ((1 << (8 - remaining_bits)) - 1);
break; break;
// Ports // Ports
case SINGLE_LOCAL_PORT_TYPE: case SINGLE_LOCAL_PORT_TYPE:
active_filters = SINGLE_LOCAL_PORT_FLAG; active_filters |= SINGLE_LOCAL_PORT_FLAG;
memcpy(&single_local_port, &tft.filter[idx], 2); memcpy(&single_local_port, &tft.filter[idx], 2);
idx += 2; idx += 2;
break; break;
case SINGLE_REMOTE_PORT_TYPE: case SINGLE_REMOTE_PORT_TYPE:
active_filters = SINGLE_REMOTE_PORT_FLAG; active_filters |= SINGLE_REMOTE_PORT_FLAG;
memcpy(&single_remote_port, &tft.filter[idx], 2); memcpy(&single_remote_port, &tft.filter[idx], 2);
idx += 2; idx += 2;
break; break;
case LOCAL_PORT_RANGE_TYPE: case LOCAL_PORT_RANGE_TYPE:
active_filters |= LOCAL_PORT_RANGE_FLAG;
memcpy(&local_port_range[0], &tft.filter[idx], 2);
memcpy(&local_port_range[1], &tft.filter[idx + 2], 2);
if (local_port_range[0] > local_port_range[1]) { // wrong order
uint16_t t = local_port_range[0];
local_port_range[0] = local_port_range[1];
local_port_range[1] = t;
}
idx += 4;
break; break;
case REMOTE_PORT_RANGE_TYPE: case REMOTE_PORT_RANGE_TYPE:
active_filters |= REMOTE_PORT_RANGE_FLAG;
memcpy(&remote_port_range[0], &tft.filter[idx], 2);
memcpy(&remote_port_range[1], &tft.filter[idx + 2], 2);
if (remote_port_range[0] > remote_port_range[1]) { // wrong order
uint16_t t = remote_port_range[0];
remote_port_range[0] = remote_port_range[1];
remote_port_range[1] = t;
}
idx += 4;
break; break;
// Protocol/Next Header // Protocol/Next Header
case PROTOCOL_ID_TYPE: case PROTOCOL_ID_TYPE:
active_filters |= PROTOCOL_ID_FLAG;
protocol_id = tft.filter[idx++];
break; break;
// Type of service/Traffic class // Type of service/Traffic class
case TYPE_OF_SERVICE_TYPE: case TYPE_OF_SERVICE_TYPE:
active_filters = TYPE_OF_SERVICE_FLAG; active_filters |= TYPE_OF_SERVICE_FLAG;
memcpy(&type_of_service, &tft.filter[idx], 1); type_of_service = tft.filter[idx++];
idx += 1; type_of_service_mask = tft.filter[idx++];
memcpy(&type_of_service_mask, &tft.filter[idx], 1);
idx += 1;
break; break;
// Flow label // Flow label
case FLOW_LABEL_TYPE: case FLOW_LABEL_TYPE:
active_filters |= FLOW_LABEL_FLAG;
memcpy(&flow_label, &tft.filter[idx], 3);
idx += 3;
break; break;
// IPsec security parameter // IPsec security parameter
case SECURITY_PARAMETER_INDEX_TYPE: case SECURITY_PARAMETER_INDEX_TYPE:
active_filters |= SECURITY_PARAMETER_INDEX_FLAG;
memcpy(&security_parameter_index, &tft.filter[idx], 4);
idx += 4;
break; break;
default: default:
log->error("ERROR: wrong type: 0x%02x\n", filter_type);
return; return;
} }
} }
} }
bool inline tft_packet_filter_t::filter_contains(uint16_t filtertype)
{
return (active_filters & filtertype) != 0;
}
/* /*
* Implements packet matching against the packet filter componenets as specified in TS 24.008, section 10.5.6.12. * Implements packet matching against the packet filter componenets as specified in TS 24.008, section 10.5.6.12.
* *
@ -119,22 +201,22 @@ bool tft_packet_filter_t::match(const srslte::unique_byte_buffer_t& pdu)
} }
// Match IP Header to active filters // Match IP Header to active filters
if ((active_filters & ip_flags) != 0 && !match_ip(pdu)) { if (filter_contains(ip_flags) && !match_ip(pdu)) {
return false; return false;
} }
// Check Protocol ID/Next Header Field // Check Protocol ID/Next Header Field
if ((active_filters & PROTOCOL_ID_FLAG) != 0 && !match_protocol(pdu)) { if (filter_contains(PROTOCOL_ID_FLAG) && !match_protocol(pdu)) {
return false; return false;
} }
// Check Ports/Port Range // Check Ports/Port Range
if ((active_filters & port_flags) != 0 && !match_port(pdu)) { if (filter_contains(port_flags) && !match_port(pdu)) {
return false; return false;
} }
// Check Type of Service/Traffic class // Check Type of Service/Traffic class
if ((active_filters & TYPE_OF_SERVICE_FLAG) != 0 && !match_type_of_service(pdu)) { if (filter_contains(TYPE_OF_SERVICE_FLAG) && !match_type_of_service(pdu)) {
return false; return false;
} }
@ -145,21 +227,32 @@ bool tft_packet_filter_t::match_ip(const srslte::unique_byte_buffer_t& pdu)
{ {
struct iphdr* ip_pkt = (struct iphdr*)pdu->msg; struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg; struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
// It is implied, that this is always an OUTGOING packet
if (ip_pkt->version == 4) { if (ip_pkt->version == 4) {
// Check match on IPv4 packet // Check match on IPv4 packet
if (active_filters & IPV4_LOCAL_ADDR_FLAG) { if (filter_contains(IPV4_LOCAL_ADDR_FLAG)) {
if (memcmp(&ipv4_local_addr, &ip_pkt->saddr, IPV4_ADDR_SIZE) != 0) { if ((ip_pkt->saddr & ipv4_local_addr_mask) != (ipv4_local_addr & ipv4_local_addr_mask)) {
return false; return false;
} }
} }
if (active_filters & IPV4_REMOTE_ADDR_FLAG) {
if (memcmp(&ipv4_remote_addr, &ip_pkt->daddr, IPV4_ADDR_SIZE) != 0) { if (filter_contains(IPV4_REMOTE_ADDR_FLAG)) {
if ((ip_pkt->daddr & ipv4_remote_addr_mask) != (ipv4_remote_addr & ipv4_remote_addr_mask)) {
return false; return false;
} }
} }
} else if (ip_pkt->version == 6) { } else if (ip_pkt->version == 6) {
// Check match on IPv6 (TODO) // Check match on IPv6
if (filter_contains(IPV6_REMOTE_ADDR_FLAG | IPV6_REMOTE_ADDR_LENGTH_FLAG)) {
bool match = true;
for (int i = 0; i < ipv6_remote_addr_length; i++) {
match &= ((ipv6_remote_addr[i] ^ ip6_pkt->daddr.__in6_u.__u6_addr8[i]) & ipv6_remote_addr_mask[i]) == 0;
if (!match) {
return false;
}
}
return true;
}
} else { } else {
// Error // Error
return false; return false;
@ -178,7 +271,7 @@ bool tft_packet_filter_t::match_protocol(const srslte::unique_byte_buffer_t& pdu
return false; return false;
} }
} else if (ip_pkt->version == 6) { } else if (ip_pkt->version == 6) {
// Check match on IPv6 (TODO) // Check match on IPv6 packet
if (ip6_pkt->nexthdr != protocol_id) { if (ip6_pkt->nexthdr != protocol_id) {
return false; return false;
} }
@ -195,7 +288,7 @@ bool tft_packet_filter_t::match_type_of_service(const srslte::unique_byte_buffer
if (ip_pkt->version == 4) { if (ip_pkt->version == 4) {
// Check match on IPv4 packet // Check match on IPv4 packet
if (ip_pkt->tos != type_of_service) { if ((ip_pkt->tos ^ type_of_service) & type_of_service_mask) {
return false; return false;
} }
} else if (ip_pkt->version == 6) { } else if (ip_pkt->version == 6) {
@ -223,6 +316,7 @@ bool tft_packet_filter_t::match_port(const srslte::unique_byte_buffer_t& pdu)
struct iphdr* ip_pkt = (struct iphdr*)pdu->msg; struct iphdr* ip_pkt = (struct iphdr*)pdu->msg;
struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg; struct ipv6hdr* ip6_pkt = (struct ipv6hdr*)pdu->msg;
struct udphdr* udp_pkt; struct udphdr* udp_pkt;
struct tcphdr* tcp_pkt;
if (ip_pkt->version == 4) { if (ip_pkt->version == 4) {
switch (ip_pkt->protocol) { switch (ip_pkt->protocol) {
@ -240,7 +334,49 @@ bool tft_packet_filter_t::match_port(const srslte::unique_byte_buffer_t& pdu)
} }
break; break;
case TCP_PROTOCOL: case TCP_PROTOCOL:
tcp_pkt = (struct tcphdr*)&pdu->msg[ip_pkt->ihl * 4];
if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
if (tcp_pkt->source != single_local_port) {
return false;
}
}
if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
if (tcp_pkt->dest != single_remote_port) {
return false;
}
}
break;
default:
return false; return false;
}
} else if (ip_pkt->version == 6) {
switch (ip6_pkt->nexthdr) {
case UDP_PROTOCOL:
udp_pkt = (struct udphdr*)&pdu->msg[sizeof(ipv6hdr)];
if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
if (udp_pkt->source != single_local_port) {
return false;
}
}
if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
if (udp_pkt->dest != single_remote_port) {
return false;
}
}
break;
case TCP_PROTOCOL:
tcp_pkt = (struct tcphdr*)&pdu->msg[sizeof(ipv6hdr)];
if (active_filters & SINGLE_LOCAL_PORT_FLAG) {
if (tcp_pkt->source != single_local_port) {
return false;
}
}
if (active_filters & SINGLE_REMOTE_PORT_FLAG) {
if (tcp_pkt->dest != single_remote_port) {
return false;
}
}
break;
default: default:
return false; return false;
} }

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