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Fix impostor packet checksums.

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basil00
2018-10-27 06:52:14 +08:00
parent 86db54b400
commit 316765aa92
1 changed files with 11 additions and 14 deletions
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sys/windivert.c
+11 -14
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@@ -475,7 +475,7 @@ static BOOL windivert_queue_work(context_t context, PVOID packet,
static void windivert_queue_packet(context_t context, packet_t packet);
static void windivert_reinject_packet(packet_t packet);
static void windivert_free_packet(packet_t packet);
static BOOL windivert_decrement_ttl(PVOID data, BOOL ipv4, BOOL checksum);
static BOOL windivert_decrement_ttl(PVOID data, BOOL ipv4);
static int windivert_big_num_compare(const UINT32 *a, const UINT32 *b);
static BOOL windivert_parse_headers(PNET_BUFFER buffer, BOOL ipv4,
PWINDIVERT_IPHDR *ip_header_ptr, PWINDIVERT_IPV6HDR *ipv6_header_ptr,
@@ -2243,8 +2243,7 @@ windivert_write_bad_packet:
}
// Decrement TTL for impostor packets:
if (addr->Impostor && !windivert_decrement_ttl(data_copy, ipv4,
(addr->PseudoIPChecksum == 0)))
if (addr->Impostor && !windivert_decrement_ttl(data_copy, ipv4))
{
status = STATUS_HOPLIMIT_EXCEEDED;
goto windivert_write_exit;
@@ -4286,7 +4285,7 @@ static void windivert_free_packet(packet_t packet)
/*
* Decrement the TTL of a packet.
*/
static BOOL windivert_decrement_ttl(PVOID data, BOOL ipv4, BOOL checksum)
static BOOL windivert_decrement_ttl(PVOID data, BOOL ipv4)
{
PWINDIVERT_IPHDR ip_header;
PWINDIVERT_IPV6HDR ipv6_header;
@@ -4299,17 +4298,15 @@ static BOOL windivert_decrement_ttl(PVOID data, BOOL ipv4, BOOL checksum)
return FALSE;
}
ip_header->TTL--;
if (checksum)
// Incremental checksum update:
if (ip_header->Checksum >= 0xFFFE)
{
// Incremental checksum update:
if (ip_header->Checksum >= 0xFFFE)
{
ip_header->Checksum -= 0xFFFE;
}
else
{
ip_header->Checksum += 1;
}
ip_header->Checksum -= 0xFFFE;
}
else
{
ip_header->Checksum += 1;
}
}
else