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Add support for pseudo IP/TCP/UDP checksums.

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Most NIC cards support checksum offloading,
meaning that it is not necessary to calculate the
full IP/TCP/UDP checksums for injected packets.
WINDIVERT_ADDRESS has been extended to include 3
extra flags that indicate if the packet has full
or pseudo checksums.  This is a WIP.
This commit is contained in:
basil00
2017-11-09 22:11:13 +08:00
parent bbf6a34aa6
commit aea3a3a858
8 changed files with 194 additions and 252 deletions
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examples/webfilter/webfilter.c
+3 -5
View File
@@ -189,8 +189,6 @@ int __cdecl main(int argc, char **argv)
!BlackListPayloadMatch(blacklist, payload, (UINT16)payload_len))
{
// Packet does not match the blacklist; simply reinject it.
WinDivertHelperCalcChecksums(packet, packet_len,
WINDIVERT_HELPER_NO_REPLACE);
if (!WinDivertSend(handle, packet, packet_len, &addr, NULL))
{
fprintf(stderr, "warning: failed to reinject packet (%d)\n",
@@ -210,7 +208,7 @@ int __cdecl main(int argc, char **argv)
reset->tcp.DstPort = htons(80);
reset->tcp.SeqNum = tcp_header->SeqNum;
reset->tcp.AckNum = tcp_header->AckNum;
WinDivertHelperCalcChecksums((PVOID)reset, sizeof(PACKET), 0);
WinDivertHelperCalcChecksums((PVOID)reset, sizeof(PACKET), &addr, 0);
if (!WinDivertSend(handle, (PVOID)reset, sizeof(PACKET), &addr, NULL))
{
fprintf(stderr, "warning: failed to send reset packet (%d)\n",
@@ -224,8 +222,8 @@ int __cdecl main(int argc, char **argv)
blockpage->header.tcp.SeqNum = tcp_header->AckNum;
blockpage->header.tcp.AckNum =
htonl(ntohl(tcp_header->SeqNum) + payload_len);
WinDivertHelperCalcChecksums((PVOID)blockpage, blockpage_len, 0);
addr.Direction = !addr.Direction; // Reverse direction.
WinDivertHelperCalcChecksums((PVOID)blockpage, blockpage_len, &addr, 0);
if (!WinDivertSend(handle, (PVOID)blockpage, blockpage_len, &addr,
NULL))
{
@@ -243,7 +241,7 @@ int __cdecl main(int argc, char **argv)
htonl(ntohl(tcp_header->AckNum) + sizeof(block_data) - 1);
finish->tcp.AckNum =
htonl(ntohl(tcp_header->SeqNum) + payload_len);
WinDivertHelperCalcChecksums((PVOID)finish, sizeof(PACKET), 0);
WinDivertHelperCalcChecksums((PVOID)finish, sizeof(PACKET), &addr, 0);
if (!WinDivertSend(handle, (PVOID)finish, sizeof(PACKET), &addr, NULL))
{
fprintf(stderr, "warning: failed to send finish packet (%d)\n",