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C

/*
* passthru.c
* (C) 2018, all rights reserved,
*
* This file is part of WinDivert.
*
* WinDivert 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.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
* WinDivert is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/*
* DESCRIPTION:
* This program does nothing except divert packets and re-inject them. This is
* useful for performance testing.
*
* usage: netdump.exe windivert-filter num-threads
*/
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "windivert.h"
#define MAXBUF 400000
#define MAXBATCH 0xFF
static int batch = 1;
static DWORD passthru(LPVOID arg);
/*
* Entry.
*/
int __cdecl main(int argc, char **argv)
{
int num_threads, priority = 0, i;
HANDLE handle, thread;
if (argc < 3 || argc > 5)
{
fprintf(stderr, "usage: %s filter num-threads [batch] [priority]\n",
argv[0]);
exit(EXIT_FAILURE);
}
num_threads = atoi(argv[2]);
if (num_threads < 1 || num_threads > 64)
{
fprintf(stderr, "error: invalid number of threads\n");
exit(EXIT_FAILURE);
}
if (argc >= 4)
{
batch = atoi(argv[3]);
}
if (batch <= 0 || batch > MAXBATCH)
{
fprintf(stderr, "error: invalid batch size\n");
exit(EXIT_FAILURE);
}
if (argc >= 5)
{
priority = atoi(argv[4]);
}
// Divert traffic matching the filter:
handle = WinDivertOpen(argv[1], WINDIVERT_LAYER_NETWORK, (INT16)priority,
0);
if (handle == INVALID_HANDLE_VALUE)
{
if (GetLastError() == ERROR_INVALID_PARAMETER)
{
fprintf(stderr, "error: filter syntax error\n");
exit(EXIT_FAILURE);
}
fprintf(stderr, "error: failed to open the WinDivert device (%d)\n",
GetLastError());
exit(EXIT_FAILURE);
}
// Start the threads
for (i = 1; i < num_threads; i++)
{
thread = CreateThread(NULL, 1, (LPTHREAD_START_ROUTINE)passthru,
(LPVOID)handle, 0, NULL);
if (thread == NULL)
{
fprintf(stderr, "error: failed to start passthru thread (%u)\n",
GetLastError());
exit(EXIT_FAILURE);
}
}
// Main thread:
passthru((LPVOID)handle);
return 0;
}
// Passthru thread.
static DWORD passthru(LPVOID arg)
{
UINT8 packet[MAXBUF];
UINT packet_len, addr_len;
WINDIVERT_ADDRESS addr[MAXBATCH];
HANDLE handle = (HANDLE)arg;
// Main loop:
while (TRUE)
{
// Read a matching packet.
addr_len = batch * sizeof(WINDIVERT_ADDRESS);
if (!WinDivertRecvEx(handle, packet, sizeof(packet), &packet_len, 0,
addr, &addr_len, NULL))
{
fprintf(stderr, "warning: failed to read packet (%d)\n",
GetLastError());
continue;
}
// Re-inject the matching packet.
if (!WinDivertSendEx(handle, packet, packet_len, NULL, 0, addr,
addr_len, NULL))
{
fprintf(stderr, "warning: failed to reinject packet (%d)\n",
GetLastError());
}
}
}