Max/basil00_WinDivert
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Figured out a way to split the "address" part of the buffer from the packet

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data itself.  This makes for a much cleaner interface.

sys/divert.c
dll/divert.c
include/*.h
	DivertRecv and DivertSend now use IOCTLs instead of reads/writes.
	The 'address' parameter is passed by pointer to the driver, which
	writes directly to it (after sanity checks).
	This means that the data buffer now only contains the packet, which
	help to avoid some messy code.

examples/*/*.c
	Update the examples to reflect the new API.

doc/divert.html
	Update the documentation to reflect the new API.
This commit is contained in:
basil00
2011-08-21 17:59:13 +08:00
parent cf80d12e5d
commit ee386df032
8 changed files with 371 additions and 375 deletions
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examples/webfilter/webfilter.c
+14 -25
View File
@@ -55,7 +55,6 @@ typedef struct
*/
typedef struct
{
DIVERT_PACKET divert;
DIVERT_IPHDR ip;
DIVERT_TCPHDR tcp;
} PACKET, *PPACKET;
@@ -105,9 +104,9 @@ static BOOL BlackListPayloadMatch(PBLACKLIST blacklist, char *data,
int main(int argc, char **argv)
{
HANDLE handle;
DIVERT_ADDRESS addr;
UINT8 packet[MAXBUF];
PDIVERT_PACKET ppacket = (PDIVERT_PACKET)packet;
UINT ppacket_len;
UINT packet_len;
PDIVERT_IPHDR ip_header;
PDIVERT_TCPHDR tcp_header;
PVOID payload;
@@ -142,8 +141,7 @@ int main(int argc, char **argv)
exit(EXIT_FAILURE);
}
PacketInit(&blockpage->header);
blockpage->header.ip.Length =
htons(blockpage_len - sizeof(DIVERT_PACKET));
blockpage->header.ip.Length = htons(blockpage_len);
blockpage->header.tcp.SrcPort = htons(80);
blockpage->header.tcp.Psh = 1;
blockpage->header.tcp.Ack = 1;
@@ -170,19 +168,19 @@ int main(int argc, char **argv)
// Main loop:
while (TRUE)
{
if (!DivertRecv(handle, ppacket, sizeof(packet), &ppacket_len))
if (!DivertRecv(handle, packet, sizeof(packet), &addr, &packet_len))
{
fprintf(stderr, "warning: failed to read packet (%d)\n",
GetLastError());
continue;
}
if (!DivertHelperParse(ppacket, ppacket_len, &ip_header, NULL, NULL,
if (!DivertHelperParse(packet, packet_len, &ip_header, NULL, NULL,
NULL, &tcp_header, NULL, &payload, &payload_len) ||
!BlackListPayloadMatch(blacklist, payload, (UINT16)payload_len))
{
// Packet does not match the blacklist; simply reinject it.
if (!DivertSend(handle, ppacket, ppacket_len, NULL))
if (!DivertSend(handle, packet, packet_len, &addr, NULL))
{
fprintf(stderr, "warning: failed to reinject packet (%d)\n",
GetLastError());
@@ -195,35 +193,29 @@ int main(int argc, char **argv)
// (1) Send a TCP RST to the server; immediately closing the
// connection at the server's end.
reset->divert.IfIdx = ppacket->IfIdx;
reset->divert.SubIfIdx = ppacket->SubIfIdx;
reset->divert.Direction = ppacket->Direction;
reset->ip.SrcAddr = ip_header->SrcAddr;
reset->ip.DstAddr = ip_header->DstAddr;
reset->tcp.SrcPort = tcp_header->SrcPort;
reset->tcp.DstPort = htons(80);
reset->tcp.SeqNum = tcp_header->SeqNum;
reset->tcp.AckNum = tcp_header->AckNum;
DivertHelperCalcChecksums((PDIVERT_PACKET)reset, sizeof(PACKET), 0);
if (!DivertSend(handle, (PDIVERT_PACKET)reset, sizeof(PACKET), NULL))
DivertHelperCalcChecksums((PVOID)reset, sizeof(PACKET), 0);
if (!DivertSend(handle, (PVOID)reset, sizeof(PACKET), &addr, NULL))
{
fprintf(stderr, "warning: failed to send reset packet (%d)\n",
GetLastError());
}
// (2) Send the blockpage to the browser:
blockpage->header.divert.IfIdx = ppacket->IfIdx;
blockpage->header.divert.SubIfIdx = ppacket->SubIfIdx;
blockpage->header.divert.Direction = !ppacket->Direction;
blockpage->header.ip.SrcAddr = ip_header->DstAddr;
blockpage->header.ip.DstAddr = ip_header->SrcAddr;
blockpage->header.tcp.DstPort = tcp_header->SrcPort;
blockpage->header.tcp.SeqNum = tcp_header->AckNum;
blockpage->header.tcp.AckNum =
htonl(ntohl(tcp_header->SeqNum) + payload_len);
DivertHelperCalcChecksums((PDIVERT_PACKET)blockpage, blockpage_len, 0);
if (!DivertSend(handle, (PDIVERT_PACKET)blockpage, blockpage_len,
NULL))
DivertHelperCalcChecksums((PVOID)blockpage, blockpage_len, 0);
addr.Direction = !addr.Direction; // Reverse direction.
if (!DivertSend(handle, (PVOID)blockpage, blockpage_len, &addr, NULL))
{
fprintf(stderr, "warning: failed to send block page packet (%d)\n",
GetLastError());
@@ -231,9 +223,6 @@ int main(int argc, char **argv)
// (3) Send a TCP RST to the browser; closing the connection at the
// browser's end.
reset->divert.IfIdx = ppacket->IfIdx;
reset->divert.SubIfIdx = ppacket->SubIfIdx;
reset->divert.Direction = !ppacket->Direction;
reset->ip.SrcAddr = ip_header->DstAddr;
reset->ip.DstAddr = ip_header->SrcAddr;
reset->tcp.SrcPort = htons(80);
@@ -242,8 +231,8 @@ int main(int argc, char **argv)
htonl(ntohl(tcp_header->AckNum) + sizeof(block_data) - 1);
reset->tcp.AckNum =
htonl(ntohl(tcp_header->SeqNum) + payload_len);
DivertHelperCalcChecksums((PDIVERT_PACKET)reset, sizeof(PACKET), 0);
if (!DivertSend(handle, (PDIVERT_PACKET)reset, sizeof(PACKET), NULL))
DivertHelperCalcChecksums((PVOID)reset, sizeof(PACKET), 0);
if (!DivertSend(handle, (PVOID)reset, sizeof(PACKET), &addr, NULL))
{
fprintf(stderr, "warning: failed to send reset packet (%d)\n",
GetLastError());
@@ -259,7 +248,7 @@ static void PacketInit(PPACKET packet)
memset(packet, 0, sizeof(PACKET));
packet->ip.Version = 4;
packet->ip.HdrLength = sizeof(DIVERT_IPHDR) / sizeof(UINT32);
packet->ip.Length = htons(sizeof(PACKET) - sizeof(DIVERT_PACKET));
packet->ip.Length = htons(sizeof(PACKET));
packet->ip.TTL = 64;
packet->ip.Protocol = IPPROTO_TCP;
packet->tcp.HdrLength = sizeof(DIVERT_TCPHDR) / sizeof(UINT32);