366 lines
9.6 KiB
C++
366 lines
9.6 KiB
C++
|
|
#ifndef NFQUEUE_CLASS_CPP
|
|
#define NFQUEUE_CLASS_CPP
|
|
|
|
#include <libnetfilter_queue/libnetfilter_queue.h>
|
|
#include <linux/netfilter/nfnetlink_queue.h>
|
|
#include <tins/tcp_ip/stream_identifier.h>
|
|
#include <libmnl/libmnl.h>
|
|
#include <tins/tins.h>
|
|
|
|
using namespace std;
|
|
|
|
namespace Firegex{
|
|
namespace NfQueue{
|
|
|
|
enum class FilterAction{ DROP, ACCEPT, MANGLE, NOACTION };
|
|
enum class L4Proto { TCP, UDP, RAW };
|
|
typedef Tins::TCPIP::StreamIdentifier stream_id;
|
|
|
|
|
|
template<typename T>
|
|
class PktRequest {
|
|
private:
|
|
FilterAction action = FilterAction::NOACTION;
|
|
mnl_socket* nl = nullptr;
|
|
uint16_t res_id;
|
|
uint32_t packet_id;
|
|
public:
|
|
bool is_ipv6;
|
|
Tins::IP* ipv4 = nullptr;
|
|
Tins::IPv6* ipv6 = nullptr;
|
|
Tins::TCP* tcp = nullptr;
|
|
Tins::UDP* udp = nullptr;
|
|
L4Proto l4_proto;
|
|
bool is_input;
|
|
|
|
string packet;
|
|
char* data;
|
|
size_t data_size;
|
|
stream_id sid;
|
|
|
|
T* ctx;
|
|
|
|
private:
|
|
|
|
inline void fetch_data_size(Tins::PDU* pdu){
|
|
auto inner = pdu->inner_pdu();
|
|
if (inner == nullptr){
|
|
data_size = 0;
|
|
}else{
|
|
data_size = inner->size();
|
|
}
|
|
}
|
|
|
|
L4Proto fill_l4_info(){
|
|
if (is_ipv6){
|
|
tcp = ipv6->find_pdu<Tins::TCP>();
|
|
if (tcp == nullptr){
|
|
udp = ipv6->find_pdu<Tins::UDP>();
|
|
if (udp == nullptr){
|
|
fetch_data_size(ipv6);
|
|
return L4Proto::RAW;
|
|
}else{
|
|
fetch_data_size(udp);
|
|
return L4Proto::UDP;
|
|
}
|
|
}else{
|
|
fetch_data_size(tcp);
|
|
return L4Proto::TCP;
|
|
}
|
|
}else{
|
|
tcp = ipv4->find_pdu<Tins::TCP>();
|
|
if (tcp == nullptr){
|
|
udp = ipv4->find_pdu<Tins::UDP>();
|
|
if (udp == nullptr){
|
|
fetch_data_size(ipv4);
|
|
return L4Proto::RAW;
|
|
}else{
|
|
fetch_data_size(udp);
|
|
return L4Proto::UDP;
|
|
}
|
|
}else{
|
|
fetch_data_size(tcp);
|
|
return L4Proto::TCP;
|
|
}
|
|
}
|
|
}
|
|
|
|
public:
|
|
|
|
PktRequest(const char* payload, size_t plen, T* ctx, mnl_socket* nl, nfgenmsg *nfg, nfqnl_msg_packet_hdr *ph, bool is_input):
|
|
ctx(ctx), nl(nl), res_id(nfg->res_id),
|
|
packet_id(ph->packet_id), is_input(is_input),
|
|
packet(string(payload, plen)),
|
|
is_ipv6((payload[0] & 0xf0) == 0x60){
|
|
if (is_ipv6){
|
|
ipv6 = new Tins::IPv6((uint8_t*)packet.c_str(), plen);
|
|
sid = stream_id::make_identifier(*ipv6);
|
|
}else{
|
|
ipv4 = new Tins::IP((uint8_t*)packet.c_str(), plen);
|
|
sid = stream_id::make_identifier(*ipv4);
|
|
}
|
|
l4_proto = fill_l4_info();
|
|
data = packet.data()+(plen-data_size);
|
|
}
|
|
|
|
void drop(){
|
|
if (action == FilterAction::NOACTION){
|
|
action = FilterAction::DROP;
|
|
perfrom_action();
|
|
}else{
|
|
throw invalid_argument("Cannot drop a packet that has already been dropped or accepted");
|
|
}
|
|
}
|
|
|
|
void accept(){
|
|
if (action == FilterAction::NOACTION){
|
|
action = FilterAction::ACCEPT;
|
|
perfrom_action();
|
|
}else{
|
|
throw invalid_argument("Cannot accept a packet that has already been dropped or accepted");
|
|
}
|
|
}
|
|
|
|
void mangle(){
|
|
if (action == FilterAction::NOACTION){
|
|
action = FilterAction::MANGLE;
|
|
perfrom_action();
|
|
}else{
|
|
throw invalid_argument("Cannot mangle a packet that has already been accepted or dropped");
|
|
}
|
|
}
|
|
|
|
FilterAction get_action(){
|
|
return action;
|
|
}
|
|
|
|
~PktRequest(){
|
|
delete ipv4;
|
|
delete ipv6;
|
|
}
|
|
|
|
private:
|
|
void perfrom_action(){
|
|
char buf[MNL_SOCKET_BUFFER_SIZE];
|
|
struct nlmsghdr *nlh_verdict = nfq_nlmsg_put(buf, NFQNL_MSG_VERDICT, ntohs(res_id));
|
|
switch (action)
|
|
{
|
|
case FilterAction::ACCEPT:
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(packet_id), NF_ACCEPT );
|
|
break;
|
|
case FilterAction::DROP:
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(packet_id), NF_DROP );
|
|
break;
|
|
case FilterAction::MANGLE:{
|
|
if (is_ipv6){
|
|
nfq_nlmsg_verdict_put_pkt(nlh_verdict, ipv6->serialize().data(), ipv6->size());
|
|
}else{
|
|
nfq_nlmsg_verdict_put_pkt(nlh_verdict, ipv4->serialize().data(), ipv4->size());
|
|
}
|
|
nfq_nlmsg_verdict_put(nlh_verdict, ntohl(packet_id), NF_ACCEPT );
|
|
break;
|
|
}
|
|
default:
|
|
throw invalid_argument("Invalid action");
|
|
}
|
|
if (mnl_socket_sendto(nl, nlh_verdict, nlh_verdict->nlmsg_len) < 0) {
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
}
|
|
|
|
};
|
|
|
|
struct internal_nfqueue_execution_data_tmp{
|
|
mnl_socket* nl = nullptr;
|
|
void *data = nullptr;
|
|
};
|
|
|
|
const size_t NFQUEUE_BUFFER_SIZE = 0xffff + (MNL_SOCKET_BUFFER_SIZE/2);
|
|
/* NfQueue wrapper class to handle nfqueue packets
|
|
this class is made to be possible enqueue multiple packets to multiple threads
|
|
--> handle function is responsable to delete the PktRequest object */
|
|
template <typename D, void handle_func(PktRequest<D>*)>
|
|
class NfQueue {
|
|
private:
|
|
mnl_socket* nl = nullptr;
|
|
unsigned int portid;
|
|
public:
|
|
char* queue_msg_buffer = nullptr;
|
|
const uint16_t queue_num;
|
|
|
|
NfQueue(u_int16_t queue_num): queue_num(queue_num) {
|
|
queue_msg_buffer = new char[NFQUEUE_BUFFER_SIZE];
|
|
nl = mnl_socket_open(NETLINK_NETFILTER);
|
|
|
|
if (nl == nullptr) { throw runtime_error( "mnl_socket_open" );}
|
|
|
|
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
|
|
mnl_socket_close(nl);
|
|
throw runtime_error( "mnl_socket_bind" );
|
|
}
|
|
portid = mnl_socket_get_portid(nl);
|
|
|
|
if (_send_config_cmd(NFQNL_CFG_CMD_BIND) < 0) {
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
//TEST if BIND was successful
|
|
if (_send_config_cmd(NFQNL_CFG_CMD_NONE) < 0) { // SEND A NONE command to generate an error meessage
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
if (_recv_packet() == -1) { //RECV the error message
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_recvfrom" );
|
|
}
|
|
|
|
struct nlmsghdr *nlh = (struct nlmsghdr *) queue_msg_buffer;
|
|
|
|
if (nlh->nlmsg_type != NLMSG_ERROR) {
|
|
_clear();
|
|
throw runtime_error( "unexpected packet from kernel (expected NLMSG_ERROR packet)" );
|
|
}
|
|
//nfqnl_msg_config_cmd
|
|
nlmsgerr* error_msg = (nlmsgerr *)mnl_nlmsg_get_payload(nlh);
|
|
|
|
// error code taken from the linux kernel:
|
|
// https://elixir.bootlin.com/linux/v5.18.12/source/include/linux/errno.h#L27
|
|
#define ENOTSUPP 524 /* Operation is not supported */
|
|
|
|
if (error_msg->error != -ENOTSUPP) {
|
|
_clear();
|
|
throw invalid_argument( "queueid is already busy" );
|
|
}
|
|
|
|
//END TESTING BIND
|
|
nlh = nfq_nlmsg_put(queue_msg_buffer, NFQNL_MSG_CONFIG, queue_num);
|
|
nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff);
|
|
|
|
#ifdef NFQUEUE_FAIL_OPEN
|
|
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(NFQA_CFG_F_GSO|NFQA_CFG_F_FAIL_OPEN));
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(NFQA_CFG_F_GSO|NFQA_CFG_F_FAIL_OPEN));
|
|
|
|
#else
|
|
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(NFQA_CFG_F_GSO));
|
|
mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(NFQA_CFG_F_GSO));
|
|
|
|
#endif
|
|
|
|
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
|
|
_clear();
|
|
throw runtime_error( "mnl_socket_send" );
|
|
}
|
|
|
|
/*
|
|
* ENOBUFS is signalled to userspace when packets were lost
|
|
* on kernel side. In most cases, userspace isn't interested
|
|
* in this information, so turn it off.
|
|
*/
|
|
int tmp = 1;
|
|
mnl_socket_setsockopt(nl, NETLINK_NO_ENOBUFS, &tmp, sizeof(int));
|
|
|
|
}
|
|
|
|
void handle_next_packet(D* data){
|
|
int ret = _recv_packet();
|
|
if (ret == -1) {
|
|
throw runtime_error( "mnl_socket_recvfrom" );
|
|
}
|
|
internal_nfqueue_execution_data_tmp raw_ptr = {
|
|
nl: nl,
|
|
data: data
|
|
};
|
|
|
|
ret = mnl_cb_run(queue_msg_buffer, ret, 0, portid, _real_queue_cb, &raw_ptr);
|
|
if (ret <= 0){
|
|
cerr << "[error] [NfQueue.handle_next_packet] mnl_cb_run error with: " << ret << endl;
|
|
throw runtime_error( "mnl_cb_run error!" );
|
|
}
|
|
}
|
|
|
|
~NfQueue() {
|
|
_send_config_cmd(NFQNL_CFG_CMD_UNBIND);
|
|
_clear();
|
|
}
|
|
|
|
private:
|
|
|
|
static int _real_queue_cb(const nlmsghdr *nlh, void *data_ptr) {
|
|
|
|
internal_nfqueue_execution_data_tmp* info = (internal_nfqueue_execution_data_tmp*) data_ptr;
|
|
|
|
//Extract attributes from the nlmsghdr
|
|
nlattr *attr[NFQA_MAX+1] = {};
|
|
|
|
if (nfq_nlmsg_parse(nlh, attr) < 0) {
|
|
cerr << "[error] [NfQueue._real_queue_cb] problems parsing" << endl;
|
|
return MNL_CB_ERROR;
|
|
}
|
|
if (attr[NFQA_PACKET_HDR] == nullptr) {
|
|
cerr << "[error] [NfQueue._real_queue_cb] packet header not set" << endl;
|
|
return MNL_CB_ERROR;
|
|
}
|
|
if (attr[NFQA_MARK] == nullptr) {
|
|
cerr << "[error] [NfQueue._real_queue_cb] mark not set" << endl;
|
|
return MNL_CB_ERROR;
|
|
}
|
|
|
|
//Get Payload
|
|
uint16_t plen = mnl_attr_get_payload_len(attr[NFQA_PAYLOAD]);
|
|
char *payload = (char *)mnl_attr_get_payload(attr[NFQA_PAYLOAD]);
|
|
|
|
//Return result to the kernel
|
|
struct nfqnl_msg_packet_hdr *ph = (nfqnl_msg_packet_hdr*) mnl_attr_get_payload(attr[NFQA_PACKET_HDR]);
|
|
struct nfgenmsg *nfg = (nfgenmsg *)mnl_nlmsg_get_payload(nlh);
|
|
|
|
bool is_input = ntohl(mnl_attr_get_u32(attr[NFQA_MARK])) & 0x1; // == 0x1337 that is odd
|
|
handle_func(new PktRequest<D>(
|
|
payload, plen, (D*)info->data, info->nl, nfg, ph, is_input
|
|
));
|
|
|
|
return MNL_CB_OK;
|
|
}
|
|
|
|
inline void _clear(){
|
|
if (nl != nullptr) {
|
|
mnl_socket_close(nl);
|
|
nl = nullptr;
|
|
}
|
|
delete[] queue_msg_buffer;
|
|
}
|
|
|
|
inline ssize_t _send_config_cmd(nfqnl_msg_config_cmds cmd){
|
|
struct nlmsghdr *nlh = nfq_nlmsg_put(queue_msg_buffer, NFQNL_MSG_CONFIG, queue_num);
|
|
nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, cmd);
|
|
return mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
|
|
}
|
|
|
|
inline ssize_t _recv_packet(){
|
|
return mnl_socket_recvfrom(nl, queue_msg_buffer, NFQUEUE_BUFFER_SIZE);
|
|
}
|
|
|
|
};
|
|
|
|
|
|
|
|
uint32_t hash_stream_id(const stream_id &sid) {
|
|
uint32_t addr_hash = 0;
|
|
const uint32_t* min_addr = reinterpret_cast<const uint32_t*>(sid.min_address.data());
|
|
const uint32_t* max_addr = reinterpret_cast<const uint32_t*>(sid.max_address.data());
|
|
addr_hash ^= min_addr[0] ^ min_addr[1] ^ min_addr[2] ^ min_addr[3];
|
|
addr_hash ^= max_addr[0] ^ max_addr[1] ^ max_addr[2] ^ max_addr[3];
|
|
|
|
uint32_t ports = (static_cast<uint32_t>(sid.min_address_port) << 16) | sid.max_address_port;
|
|
|
|
uint32_t hash = addr_hash ^ ports;
|
|
|
|
hash *= 0x9e3779b9;
|
|
|
|
return hash;
|
|
}
|
|
|
|
}}
|
|
#endif // NFQUEUE_CLASS_CPP
|