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Under “using MSTCP default behavior” I mean that you may modify incoming/outgoing packets and let TCP/IP route them. Like in case of NAT, WIndows TCP/IP stack by default routes packets coming from LAN into default gateway interface (connected to the Internet). To implement NAT you can only capture packets from external (Internet connected) network interface:
– For outgoing packets change source IP address to Internet interface assigned one and port allocated/according NAT table
-For incoming packets change destination IP/port according NAT tableThis way you use Microsoft TCP/IP routing and don’t have to implement it on your own.
Is that clear now?
Internet Gateway is only available in C++.
PassThru is basic packet filtering sample.
Under MSTCP I mean Microsoft TCP/IP stack implementation. You don’t have to use it from your application, but you can use its default behavior to solve the routing task.
Of course you can implement the routing by yourself. You can read packet from one interface, check/modify and forward to another using NDISAPI interface. You have to support you own routing table and etc.. to implement this properly. IHMO it is doable, but there is easier way…
Personally I prefer to let the MSTCP to do the routing work like it is done in Internet Gateway advanced sample http://www.ntkernel.com/w&p.php?id=31. This is very similar to what you need but the routing operation is performed by MSTCP, so probably it should help you to start.
Can I use WinpkFilter run-time libraries (from the site) to make such application?
Yes, these libraries are fully functional and you can use them for the development.
On my computer, the list of available adapters includes a “WAN Network Interface (IP)” adapter. If I attempt to send a generic Ethernet packet through this adapter, using SendPacketToAdapter(), it causes my Windows XP SP3 VMware Server instance to fault and reboot. I didn’t test for this on other computers.
This is a know issue. If you try to send packet with incorrect Ethernet header on the NDISWANIP (WAN Network Interface (IP)) it may crash the NDIS.SYS. NDISWAN uses Ethernet addresses from the packet header to identify the exact WAN link (actually bytes from Ethernet header used as an index in the WAN links table). If the index for the table is wrong NDISWAN references incorrect memory and crashes. So you should be very careful with what packet you send on NDISWANIP.
The only way it can be fixed is checking Ethernet header for WAN interface in driver and dropping packets with incorrect headers (not associated with any active WAN links). However, from other side this would add some sort of limitation to what you can do with WInpkFilter (I can imagine the situation with layered filters which uses Ethernet addresses for some sort of remapping). So dealing with this issue was left to developers who use WInpkFilter. By request this special check can be added to the driver custom build.
Well, do U have any schedule when to ship a vista/2008 version?
Hopefully in the next couple of months 🙂
1) can I make mentioned miniport driver using WinPkFilter?
In case of using WinpkFilter you even don’t need to create an extra miniport driver. You can intercept RTP packets between the physical network card and TCP/IP stack, set the QOS bits, recalculate checksums and re-inject packets back into the stack.
2) Does application need admin rights to load this driver?
You need admin rights to install the driver, not to use.
Interesting behavior, I have never heard about anything like this before and I suspect this is somehow specific to particular TCP/IP stack implementation.
INTERMEDIATE_BUFFER.m_Length indicates the total size of the buffers containing packet data which were indicated from the NIC to MSTCP OR sent by MSTCP to NIC. So this is a system specific value, it is not taken/calculated from packet headers.
In the meantime NeT Firewall does not support Windows 2008 because of the serious changes in the network stack introduced by 2008/Vista. We do plan to add Vista/2008 support in the near future.
I’m sorry, I’ve been a bit overloaded last time. I just need an to find some time to update an INF file, VirtNet driver itself rebuilds without any problems for x64.
Да вообще странно как-то, косяк компилятора, разбираться не особенно хочется. WWWCensor ищет по всему пакету, он не разбирает запросы. Но проверяет только пакеты пришедшие с 80 порта или уходящие на 80 порт. Так что в общем-то в нем нужно поменять только номер порта или сделать порт параметром командной строки. Ну и соответственно сделать так чтобы он на две строчки проверял а не на одну.
