// Passthru thread.
static DWORD passthru(LPVOID arg)
{
unsigned char packet[MAXBUF];
UINT packet_len;
WINDIVERT_ADDRESS addr;
HANDLE handle = (HANDLE)arg;
// Main loop:
while (TRUE)
{
// Read a matching packet.
if (!WinDivertRecv(handle, packet, sizeof(packet), &addr, &packet_len))
{
fprintf(stderr, "warning: failed to read packet (%d)\n",
GetLastError());
continue;
}
// Re-inject the matching packet.
if (!WinDivertSend(handle, packet, packet_len, &addr, NULL))
{
fprintf(stderr, "warning: failed to reinject packet (%d)\n",
GetLastError());
}
}
}
/*
* Entry.
*/
int __cdecl main(int argc, char **argv)
{
HANDLE handle, console;
UINT i;
INT16 priority = 0;
unsigned char packet[MAXBUF];
UINT packet_len;
WINDIVERT_ADDRESS recv_addr, send_addr;
PWINDIVERT_IPHDR ip_header;
PWINDIVERT_IPV6HDR ipv6_header;
PWINDIVERT_ICMPHDR icmp_header;
PWINDIVERT_ICMPV6HDR icmpv6_header;
PWINDIVERT_TCPHDR tcp_header;
PWINDIVERT_UDPHDR udp_header;
UINT payload_len;
const char *err_str;
TCPPACKET reset0;
PTCPPACKET reset = &reset0;
UINT8 dnr0[sizeof(ICMPPACKET) + 0x0F*sizeof(UINT32) + 8 + 1];
PICMPPACKET dnr = (PICMPPACKET)dnr0;
TCPV6PACKET resetv6_0;
PTCPV6PACKET resetv6 = &resetv6_0;
UINT8 dnrv6_0[sizeof(ICMPV6PACKET) + sizeof(WINDIVERT_IPV6HDR) +
sizeof(WINDIVERT_TCPHDR)];
PICMPV6PACKET dnrv6 = (PICMPV6PACKET)dnrv6_0;
// Check arguments.
switch (argc)
{
case 2:
break;
case 3:
priority = (INT16)atoi(argv[2]);
break;
default:
fprintf(stderr, "usage: %s windivert-filter [priority]\n",
argv[0]);
fprintf(stderr, "examples:\n");
fprintf(stderr, "\t%s true\n", argv[0]);
fprintf(stderr, "\t%s \"outbound and tcp.DstPort == 80\" 1000\n",
argv[0]);
fprintf(stderr, "\t%s \"inbound and tcp.Syn\" -400\n", argv[0]);
exit(EXIT_FAILURE);
}
// Initialize all packets.
PacketIpTcpInit(reset);
reset->tcp.Rst = 1;
reset->tcp.Ack = 1;
PacketIpIcmpInit(dnr);
dnr->icmp.Type = 3; // Destination not reachable.
dnr->icmp.Code = 3; // Port not reachable.
PacketIpv6TcpInit(resetv6);
resetv6->tcp.Rst = 1;
resetv6->tcp.Ack = 1;
PacketIpv6Icmpv6Init(dnrv6);
dnrv6->ipv6.Length = htons(sizeof(WINDIVERT_ICMPV6HDR) + 4 +
sizeof(WINDIVERT_IPV6HDR) + sizeof(WINDIVERT_TCPHDR));
dnrv6->icmpv6.Type = 1; // Destination not reachable.
dnrv6->icmpv6.Code = 4; // Port not reachable.
// Get console for pretty colors.
console = GetStdHandle(STD_OUTPUT_HANDLE);
// Divert traffic matching the filter:
handle = WinDivertOpen(argv[1], WINDIVERT_LAYER_NETWORK, priority, 0);
if (handle == INVALID_HANDLE_VALUE)
{
if (GetLastError() == ERROR_INVALID_PARAMETER &&
!WinDivertHelperCheckFilter(argv[1], WINDIVERT_LAYER_NETWORK,
&err_str, NULL))
{
fprintf(stderr, "error: invalid filter \"%s\"\n", err_str);
exit(EXIT_FAILURE);
}
fprintf(stderr, "error: failed to open the WinDivert device (%d)\n",
GetLastError());
exit(EXIT_FAILURE);
}
// Main loop:
while (TRUE)
{
// Read a matching packet.
if (!WinDivertRecv(handle, packet, sizeof(packet), &recv_addr,
&packet_len))
{
fprintf(stderr, "warning: failed to read packet\n");
continue;
}
// Print info about the matching packet.
WinDivertHelperParsePacket(packet, packet_len, &ip_header,
&ipv6_header, &icmp_header, &icmpv6_header, &tcp_header,
&udp_header, NULL, &payload_len);
if (ip_header == NULL && ipv6_header == NULL)
{
continue;
}
// Dump packet info:
SetConsoleTextAttribute(console, FOREGROUND_RED);
fputs("BLOCK ", stdout);
SetConsoleTextAttribute(console,
FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE);
if (ip_header != NULL)
{
UINT8 *src_addr = (UINT8 *)&ip_header->SrcAddr;
UINT8 *dst_addr = (UINT8 *)&ip_header->DstAddr;
printf("ip.SrcAddr=%u.%u.%u.%u ip.DstAddr=%u.%u.%u.%u ",
src_addr[0], src_addr[1], src_addr[2], src_addr[3],
dst_addr[0], dst_addr[1], dst_addr[2], dst_addr[3]);
}
if (ipv6_header != NULL)
{
UINT16 *src_addr = (UINT16 *)&ipv6_header->SrcAddr;
UINT16 *dst_addr = (UINT16 *)&ipv6_header->DstAddr;
fputs("ipv6.SrcAddr=", stdout);
for (i = 0; i < 8; i++)
{
printf("%x%c", ntohs(src_addr[i]), (i == 7? ' ': ':'));
}
fputs(" ipv6.DstAddr=", stdout);
for (i = 0; i < 8; i++)
{
printf("%x%c", ntohs(dst_addr[i]), (i == 7? ' ': ':'));
}
putchar(' ');
}
if (icmp_header != NULL)
{
printf("icmp.Type=%u icmp.Code=%u ",
icmp_header->Type, icmp_header->Code);
// Simply drop ICMP
}
if (icmpv6_header != NULL)
{
printf("icmpv6.Type=%u icmpv6.Code=%u ",
icmpv6_header->Type, icmpv6_header->Code);
// Simply drop ICMPv6
}
if (tcp_header != NULL)
{
printf("tcp.SrcPort=%u tcp.DstPort=%u tcp.Flags=",
ntohs(tcp_header->SrcPort), ntohs(tcp_header->DstPort));
if (tcp_header->Fin)
{
fputs("[FIN]", stdout);
}
if (tcp_header->Rst)
{
fputs("[RST]", stdout);
}
if (tcp_header->Urg)
{
fputs("[URG]", stdout);
}
if (tcp_header->Syn)
{
fputs("[SYN]", stdout);
}
if (tcp_header->Psh)
{
fputs("[PSH]", stdout);
}
if (tcp_header->Ack)
{
fputs("[ACK]", stdout);
}
putchar(' ');
if (ip_header != NULL && !tcp_header->Rst && !tcp_header->Fin)
{
reset->ip.SrcAddr = ip_header->DstAddr;
reset->ip.DstAddr = ip_header->SrcAddr;
reset->tcp.SrcPort = tcp_header->DstPort;
reset->tcp.DstPort = tcp_header->SrcPort;
reset->tcp.SeqNum =
(tcp_header->Ack? tcp_header->AckNum: 0);
reset->tcp.AckNum =
(tcp_header->Syn?
htonl(ntohl(tcp_header->SeqNum) + 1):
htonl(ntohl(tcp_header->SeqNum) + payload_len));
WinDivertHelperCalcChecksums((PVOID)reset, sizeof(TCPPACKET),
0);
memcpy(&send_addr, &recv_addr, sizeof(send_addr));
send_addr.Direction = !recv_addr.Direction;
if (!WinDivertSend(handle, (PVOID)reset, sizeof(TCPPACKET),
&send_addr, NULL))
{
fprintf(stderr, "warning: failed to send TCP reset (%d)\n",
GetLastError());
}
}
if (ipv6_header != NULL && !tcp_header->Rst && !tcp_header->Fin)
{
memcpy(resetv6->ipv6.SrcAddr, ipv6_header->DstAddr,
sizeof(resetv6->ipv6.SrcAddr));
memcpy(resetv6->ipv6.DstAddr, ipv6_header->SrcAddr,
sizeof(resetv6->ipv6.DstAddr));
resetv6->tcp.SrcPort = tcp_header->DstPort;
resetv6->tcp.DstPort = tcp_header->SrcPort;
resetv6->tcp.SeqNum =
(tcp_header->Ack? tcp_header->AckNum: 0);
resetv6->tcp.AckNum =
(tcp_header->Syn?
htonl(ntohl(tcp_header->SeqNum) + 1):
htonl(ntohl(tcp_header->SeqNum) + payload_len));
WinDivertHelperCalcChecksums((PVOID)resetv6,
sizeof(TCPV6PACKET), 0);
memcpy(&send_addr, &recv_addr, sizeof(send_addr));
send_addr.Direction = !recv_addr.Direction;
if (!WinDivertSend(handle, (PVOID)resetv6, sizeof(TCPV6PACKET),
&send_addr, NULL))
{
fprintf(stderr, "warning: failed to send TCP (IPV6) "
"reset (%d)\n", GetLastError());
}
}
}
if (udp_header != NULL)
{
printf("udp.SrcPort=%u udp.DstPort=%u ",
ntohs(udp_header->SrcPort), ntohs(udp_header->DstPort));
if (ip_header != NULL)
{
UINT icmp_length = ip_header->HdrLength*sizeof(UINT32) + 8;
memcpy(dnr->data, ip_header, icmp_length);
icmp_length += sizeof(ICMPPACKET);
dnr->ip.Length = htons((UINT16)icmp_length);
dnr->ip.SrcAddr = ip_header->DstAddr;
dnr->ip.DstAddr = ip_header->SrcAddr;
WinDivertHelperCalcChecksums((PVOID)dnr, icmp_length, 0);
memcpy(&send_addr, &recv_addr, sizeof(send_addr));
send_addr.Direction = !recv_addr.Direction;
if (!WinDivertSend(handle, (PVOID)dnr, icmp_length, &send_addr,
NULL))
{
fprintf(stderr, "warning: failed to send ICMP message "
"(%d)\n", GetLastError());
}
}
if (ipv6_header != NULL)
{
UINT icmpv6_length = sizeof(WINDIVERT_IPV6HDR) +
sizeof(WINDIVERT_TCPHDR);
memcpy(dnrv6->data, ipv6_header, icmpv6_length);
icmpv6_length += sizeof(ICMPV6PACKET);
memcpy(dnrv6->ipv6.SrcAddr, ipv6_header->DstAddr,
sizeof(dnrv6->ipv6.SrcAddr));
memcpy(dnrv6->ipv6.DstAddr, ipv6_header->SrcAddr,
sizeof(dnrv6->ipv6.DstAddr));
WinDivertHelperCalcChecksums((PVOID)dnrv6, icmpv6_length, 0);
memcpy(&send_addr, &recv_addr, sizeof(send_addr));
send_addr.Direction = !recv_addr.Direction;
if (!WinDivertSend(handle, (PVOID)dnrv6, icmpv6_length,
&send_addr, NULL))
{
fprintf(stderr, "warning: failed to send ICMPv6 message "
"(%d)\n", GetLastError());
}
}
}
putchar('\n');
}
}
int __cdecl main(int argc, char **argv) {
WINDIVERT_ADDRESS addr;
UINT buf_len, b, writelen;
HANDLE filter, console;
UINT64 flags = WINDIVERT_FLAG_SNIFF;
INT16 priority = 0;
unsigned char cap_buffer[65535];
if (argc >= 3) {
if (argc >= 4) {
if (strcmp(argv[3], "sniff") == 0) {
flags = WINDIVERT_FLAG_SNIFF;
} else if (strcmp(argv[3], "grab") == 0) {
flags = 0;
} else {
printf("error: unknown flag \"%s\"\n", argv[3]);
exit(EXIT_FAILURE);
}
}
if (argc >= 5) {
priority = (UINT)atoi(argv[4]);
}
filter = WinDivertOpenLayer7SubFilterEx(argv[1], argv[2], WINDIVERT_LAYER_NETWORK, priority, flags);
if (filter == 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);
}
signal(SIGINT, sigint_watchdog);
signal(SIGTERM, sigint_watchdog);
while (!can_exit) {
if (!WinDivertRecv(filter, cap_buffer, sizeof(cap_buffer), &addr, &buf_len))
{
Sleep(10);
continue;
}
for (b = 0; b < buf_len; b++) {
if ((b % 40) == 0) {
printf("\n\t");
}
if (isprint(cap_buffer[b])) {
printf("%c", cap_buffer[b]);
} else {
printf(".");
}
}
printf("\n");
if (flags == 0) {
WinDivertSend(filter, cap_buffer, buf_len, &addr, &writelen);
}
Sleep(10);
}
WinDivertClose(filter);
} else {
printf("usage: l7f.exe windivert-filter layer7-filtering sniff|grab [priority]\n"
" l7f \"outbound and true\" \"\\\"GET*HTTP/1*\\\" or \\\"POST*HTTP/1\\\"");
}
return 0;
}
static int sendAllListPackets() {
// send packet from tail to head and remove sent ones
int sendCount = 0;
UINT sendLen;
PacketNode *pnode;
#ifdef _DEBUG
// check the list is good
// might go into dead loop but it's better for debugging
PacketNode *p = head;
do {
p = p->next;
} while (p->next);
assert(p == tail);
#endif
while (!isListEmpty()) {
pnode = popNode(tail->prev);
sendLen = 0;
assert(pnode != head);
// FIXME inbound injection on any kind of packet is failing with a very high percentage
// need to contact windivert auther and wait for next release
if (!WinDivertSend(divertHandle, pnode->packet, pnode->packetLen, &(pnode->addr), &sendLen)) {
PWINDIVERT_ICMPHDR icmp_header;
PWINDIVERT_ICMPV6HDR icmpv6_header;
PWINDIVERT_IPHDR ip_header;
PWINDIVERT_IPV6HDR ipv6_header;
LOG("Failed to send a packet. (%lu)", GetLastError());
dumpPacket(pnode->packet, pnode->packetLen, &(pnode->addr));
// as noted in windivert help, reinject inbound icmp packets some times would fail
// workaround this by resend them as outbound
// TODO not sure is this even working as can't find a way to test
// need to document about this
WinDivertHelperParsePacket(pnode->packet, pnode->packetLen, &ip_header, &ipv6_header,
&icmp_header, &icmpv6_header, NULL, NULL, NULL, NULL);
if ((icmp_header || icmpv6_header) && IS_INBOUND(pnode->addr.Direction)) {
BOOL resent;
pnode->addr.Direction = WINDIVERT_DIRECTION_OUTBOUND;
if (ip_header) {
UINT32 tmp = ip_header->SrcAddr;
ip_header->SrcAddr = ip_header->DstAddr;
ip_header->DstAddr = tmp;
} else if (ipv6_header) {
UINT32 tmpArr[4];
memcpy(tmpArr, ipv6_header->SrcAddr, sizeof(tmpArr));
memcpy(ipv6_header->SrcAddr, ipv6_header->DstAddr, sizeof(tmpArr));
memcpy(ipv6_header->DstAddr, tmpArr, sizeof(tmpArr));
}
resent = WinDivertSend(divertHandle, pnode->packet, pnode->packetLen, &(pnode->addr), &sendLen);
LOG("Resend failed inbound ICMP packets as outbound: %s", resent ? "SUCCESS" : "FAIL");
InterlockedExchange16(&sendState, SEND_STATUS_SEND);
} else {
InterlockedExchange16(&sendState, SEND_STATUS_FAIL);
}
} else {
if (sendLen < pnode->packetLen) {
// TODO don't know how this can happen, or it needs to be resent like good old UDP packet
LOG("Internal Error: DivertSend truncated send packet.");
InterlockedExchange16(&sendState, SEND_STATUS_FAIL);
} else {
InterlockedExchange16(&sendState, SEND_STATUS_SEND);
}
}
freeNode(pnode);
++sendCount;
}
assert(isListEmpty()); // all packets should be sent by now
return sendCount;
}
/*
* Run a test case.
*/
static BOOL run_test(HANDLE inject_handle, const char *filter,
const char *packet, const size_t packet_len, BOOL match)
{
char buf[MAX_PACKET];
UINT buf_len, i;
DWORD iolen;
WINDIVERT_ADDRESS addr;
OVERLAPPED overlapped;
const char *err_str;
UINT err_pos;
HANDLE handle = INVALID_HANDLE_VALUE, handle0 = INVALID_HANDLE_VALUE,
event = NULL;
// (0) Verify the test data:
if (!WinDivertHelperCheckFilter(filter, WINDIVERT_LAYER_NETWORK, &err_str,
&err_pos))
{
fprintf(stderr, "error: filter string \"%s\" is invalid with error "
"\"%s\" (position=%u)\n", filter, err_str, err_pos);
goto failed;
}
memset(&addr, 0, sizeof(addr));
addr.Direction = WINDIVERT_DIRECTION_OUTBOUND;
if (WinDivertHelperEvalFilter(filter, WINDIVERT_LAYER_NETWORK,
(PVOID)packet, packet_len, &addr) != match)
{
fprintf(stderr, "error: filter \"%s\" does not match the given "
"packet\n", filter);
goto failed;
}
// (1) Open a WinDivert handle to the given filter:
handle = WinDivertOpen(filter, WINDIVERT_LAYER_NETWORK, 0, 0);
if (handle == INVALID_HANDLE_VALUE)
{
fprintf(stderr, "error: failed to open WinDivert handle for filter "
"\"%s\" (err = %d)\n", filter, GetLastError());
goto failed;
}
if (!match)
{
// Catch non-matching packets:
handle0 = handle;
handle = WinDivertOpen("true", WINDIVERT_LAYER_NETWORK, 33, 0);
if (handle == INVALID_HANDLE_VALUE)
{
fprintf(stderr, "error: failed to open WinDivert handle "
"(err = %d)\n", GetLastError());
goto failed;
}
}
// (2) Inject the packet:
if (!WinDivertSend(inject_handle, (PVOID)packet, packet_len, &addr, NULL))
{
fprintf(stderr, "error: failed to inject test packet (err = %d)\n",
GetLastError());
goto failed;
}
// (3) Wait for the packet to arrive.
// NOTE: This may fail, so set a generous time-out of 250ms.
memset(&overlapped, 0, sizeof(overlapped));
event = CreateEvent(NULL, FALSE, FALSE, NULL);
if (event == NULL)
{
fprintf(stderr, "error: failed to create event (err = %d)\n",
GetLastError());
goto failed;
}
overlapped.hEvent = event;
if (!WinDivertRecvEx(handle, buf, sizeof(buf), 0, &addr, &buf_len,
&overlapped))
{
if (GetLastError() != ERROR_IO_PENDING)
{
read_failed:
fprintf(stderr, "error: failed to read packet from WinDivert "
"handle (err = %d)\n", GetLastError());
goto failed;
}
switch (WaitForSingleObject(event, 250))
{
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
fprintf(stderr, "error: failed to read packet from WinDivert "
"handle (timeout)\n", GetLastError());
goto failed;
default:
goto read_failed;
}
if (!GetOverlappedResult(handle, &overlapped, &iolen, TRUE))
{
fprintf(stderr, "error: failed to get the overlapped result from "
"WinDivert handle (err = %d)\n", GetLastError());
goto failed;
}
buf_len = (UINT)iolen;
}
if (addr.Direction == WINDIVERT_DIRECTION_OUTBOUND)
{
WinDivertHelperCalcChecksums(buf, buf_len, 0);
}
// (4) Verify that the packet is the same.
if (buf_len != packet_len)
{
fprintf(stderr, "error: packet length mis-match, expected (%u), got "
"(%u)\n", packet_len, buf_len);
goto failed;
}
for (i = 0; i < packet_len; i++)
{
if (packet[i] != buf[i])
{
fprintf(stderr, "error: packet data mis-match, expected byte #%u "
"to be (0x%.2X), got (0x%.2X)\n", i, (unsigned char)packet[i],
(unsigned char)buf[i]);
for (i = 0; i < packet_len; i++)
{
printf("%c", (packet[i] == buf[i]? '.': 'X'));
}
putchar('\n');
goto failed;
}
}
// (5) Clean-up:
if (!WinDivertClose(handle))
{
handle = INVALID_HANDLE_VALUE;
fprintf(stderr, "error: failed to close WinDivert handle (err = %d)\n",
GetLastError());
goto failed;
}
if (handle0 != INVALID_HANDLE_VALUE)
{
if (!WinDivertClose(handle0))
{
handle0 = INVALID_HANDLE_VALUE;
fprintf(stderr, "error: failed to close WinDivert handle "
"(err = %d)\n", GetLastError());
goto failed;
}
}
CloseHandle(event);
return TRUE;
failed:
if (handle0 != INVALID_HANDLE_VALUE)
{
WinDivertClose(handle0);
}
if (handle != INVALID_HANDLE_VALUE)
{
WinDivertClose(handle);
}
if (event != NULL)
{
CloseHandle(event);
}
return FALSE;
}
int main(int argc, char *argv[]) {
static const char fragment_size_message[] =
"Fragment size should be in range [0 - 65535]\n";
int i, should_reinject = 0;
int opt;
HANDLE w_filter = NULL;
WINDIVERT_ADDRESS addr;
char packet[MAX_PACKET_SIZE];
PVOID packet_data;
UINT packetLen;
UINT packet_dataLen;
PWINDIVERT_IPHDR ppIpHdr;
PWINDIVERT_TCPHDR ppTcpHdr;
int do_passivedpi = 0, do_fragment_http = 0,
do_fragment_https = 0, do_host = 0,
do_host_removespace = 0, do_additional_space = 0;
int http_fragment_size = 2;
int https_fragment_size = 2;
char *data_addr, *data_addr_rn, *host_addr, *useragent_addr, *method_addr;
int data_len, host_len;
printf("GoodbyeDPI: Passive DPI blocker and Active DPI circumvention utility\n");
if (argc == 1) {
/* enable mode -1 by default */
do_passivedpi = do_host = do_host_removespace \
= do_fragment_http = do_fragment_https = 1;
}
while ((opt = getopt(argc, argv, "1234prsaf:e:")) != -1) {
switch (opt) {
case '1':
do_passivedpi = do_host = do_host_removespace \
= do_fragment_http = do_fragment_https = 1;
break;
case '2':
do_passivedpi = do_host = do_host_removespace \
= do_fragment_http = do_fragment_https = 1;
https_fragment_size = 40;
break;
case '3':
do_passivedpi = do_host = do_host_removespace \
= do_fragment_https = 1;
https_fragment_size = 40;
case '4':
do_passivedpi = do_host = do_host_removespace = 1;
break;
case 'p':
do_passivedpi = 1;
break;
case 'r':
do_host = 1;
break;
case 's':
do_host_removespace = 1;
break;
case 'a':
do_additional_space = 1;
do_host_removespace = 1;
break;
case 'f':
do_fragment_http = 1;
http_fragment_size = atoi(optarg);
if (http_fragment_size <= 0 || http_fragment_size > 65535) {
printf(fragment_size_message);
exit(EXIT_FAILURE);
}
break;
case 'e':
do_fragment_https = 1;
https_fragment_size = atoi(optarg);
if (https_fragment_size <= 0 || https_fragment_size > 65535) {
printf(fragment_size_message);
exit(EXIT_FAILURE);
}
break;
default:
printf("Usage: goodbyedpi.exe [OPTION...]\n"
" -p block passive DPI\n"
" -r replace Host with hoSt\n"
" -s remove space between host header and its value\n"
" -a additional space between Method and Request-URI (enables -s, may break sites)\n"
" -f [value] set HTTP fragmentation to value\n"
" -e [value] set HTTPS fragmentation to value\n"
"\n"
" -1 -p -r -s -f 2 -e 2 (most compatible mode, default)\n"
" -2 -p -r -s -f 2 -e 40 (better speed yet still compatible)\n"
" -3 -p -r -s -e 40 (even better speed)\n"
" -4 -p -r -s (best speed)\n");
exit(EXIT_FAILURE);
}
}
printf("Block passive: %d, Fragment HTTP: %d, Fragment HTTPS: %d, "
"hoSt: %d, Host no space: %d, Additional space: %d\n",
do_passivedpi, (do_fragment_http ? http_fragment_size : 0),
(do_fragment_https ? https_fragment_size : 0),
do_host, do_host_removespace, do_additional_space);
printf("\nOpening filter\n");
filter_num = 0;
if (do_passivedpi) {
/* IPv4 filter for inbound RST packets with ID = 0 or 1 */
filters[filter_num] = init(
"inbound and ip and tcp and "
"(ip.Id == 0x0001 or ip.Id == 0x0000) and "
"(tcp.SrcPort == 443 or tcp.SrcPort == 80) and tcp.Rst and "
DIVERT_NO_LOCALNETS_SRC,
WINDIVERT_FLAG_DROP);
filter_num++;
}
/*
* IPv4 filter for inbound HTTP redirection packets and
* active DPI circumvention
*/
filters[filter_num] = init("ip and tcp and "
"(inbound and (("
"((ip.Id == 0x0001 or ip.Id == 0x0000) and tcp.SrcPort == 80 and tcp.Ack) or "
"((tcp.SrcPort == 80 or tcp.SrcPort == 443) and tcp.Ack and tcp.Syn)"
") and " DIVERT_NO_LOCALNETS_SRC ") or "
"(outbound and "
"(tcp.DstPort == 80 or tcp.DstPort == 443) and tcp.Ack and "
DIVERT_NO_LOCALNETS_DST ")"
")",
0);
w_filter = filters[filter_num];
filter_num++;
for (i = 0; i < filter_num; i++) {
if (filters[i] == NULL)
die();
}
printf("Filter activated!\n");
signal(SIGINT, sigint_handler);
while (1) {
if (WinDivertRecv(w_filter, packet, sizeof(packet), &addr, &packetLen)) {
//printf("Got %s packet, len=%d!\n", addr.Direction ? "inbound" : "outbound",
// packetLen);
should_reinject = 1;
if (WinDivertHelperParsePacket(packet, packetLen, &ppIpHdr,
NULL, NULL, NULL, &ppTcpHdr, NULL, &packet_data, &packet_dataLen)) {
//printf("Got parsed packet, len=%d!\n", packet_dataLen);
/* Got a packet WITH DATA */
/* Handle INBOUND packet with data and find HTTP REDIRECT in there */
if (addr.Direction == WINDIVERT_DIRECTION_INBOUND && packet_dataLen > 16) {
/* If INBOUND packet with DATA (tcp.Ack) */
/* Drop packets from filter with HTTP 30x Redirect */
if (do_passivedpi && is_passivedpi_redirect(packet_data, packet_dataLen)) {
//printf("Dropping HTTP Redirect packet!\n");
should_reinject = 0;
}
}
/* Handle OUTBOUND packet, search for Host header */
else if (addr.Direction == WINDIVERT_DIRECTION_OUTBOUND &&
packet_dataLen > 16 && ppTcpHdr->DstPort == htons(80) &&
find_http_method_end(packet_data) &&
(do_host || do_host_removespace)) {
data_addr = find_host_header(packet_data, packet_dataLen);
if (data_addr) {
if (do_host) {
/* Replace "Host: " with "hoSt: " */
memcpy(data_addr, http_host_replace, strlen(http_host_replace));
//printf("Replaced Host header!\n");
}
if (do_additional_space && do_host_removespace) {
/* End of "Host:" without trailing space */
host_addr = data_addr + strlen(http_host_find) - 1;
method_addr = find_http_method_end(packet_data);
if (method_addr) {
memmove(method_addr + 1, method_addr, (PVOID)host_addr - (PVOID)method_addr);
}
}
else if (do_host_removespace) {
host_addr = data_addr + strlen(http_host_find);
data_addr_rn = dumb_memmem(host_addr,
packet_dataLen - ((PVOID)host_addr - packet_data),
"\r\n", 2);
if (data_addr_rn) {
/* We move Host header value by one byte to the left and then
* "insert" stolen space to the end of User-Agent value because
* some web servers are not tolerant to additional space in the
* end of Host header.
*
* Nothing is done if User-Agent header is missing.
*/
host_len = data_addr_rn - host_addr;
useragent_addr = find_useragent_header(packet_data, packet_dataLen);
if (host_len <= 253 && useragent_addr && useragent_addr > host_addr) {
/* Performing action only if User-Agent header goes after Host */
useragent_addr += strlen(http_useragent_find);
/* useragent_addr is in the beginning of User-Agent value */
data_len = packet_dataLen - ((PVOID)useragent_addr - packet_data);
data_addr_rn = dumb_memmem(useragent_addr,
data_len, "\r\n", 2);
/* data_addr_rn is in the end of User-Agent value */
if (data_addr_rn) {
data_len = (PVOID)data_addr_rn - (PVOID)host_addr;
/* Move one byte to the left from "Host:"
* to the end of User-Agen
*/
memmove(host_addr - 1, host_addr, data_len);
/* Put space in the end of User-Agent header */
*(char*)(data_addr_rn - 1) = ' ';
//printf("Replaced Host header!\n");
}
}
}
}
WinDivertHelperCalcChecksums(packet, packetLen, 0);
}
}
}
/* Else if we got TCP packet without data */
else if (WinDivertHelperParsePacket(packet, packetLen, &ppIpHdr,
NULL, NULL, NULL, &ppTcpHdr, NULL, NULL, NULL)) {
/* If we got SYN+ACK packet */
if (addr.Direction == WINDIVERT_DIRECTION_INBOUND &&
ppTcpHdr->Syn == 1) {
//printf("Changing Window Size!\n");
if (do_fragment_http && ppTcpHdr->SrcPort == htons(80)) {
change_window_size(packet, http_fragment_size);
WinDivertHelperCalcChecksums(packet, packetLen, 0);
}
else if (do_fragment_https && ppTcpHdr->SrcPort != htons(80)) {
change_window_size(packet, https_fragment_size);
WinDivertHelperCalcChecksums(packet, packetLen, 0);
}
}
}
if (should_reinject) {
//printf("Re-injecting!\n");
WinDivertSend(w_filter, packet, packetLen, &addr, NULL);
}
}
else {
// error, ignore
printf("Error receiving packet!\n");
break;
}
}
}
