Hello, I'm working on a project which wants to port a Windows-based network protocol to Linux. The protocol works as a VPN/Firewall, on packets copied from Data-Link Layer to user space. In MS Windows WinpkFilter(C) does copying from kernel space (Data-Link layer) to user space and then drops the original packet. In user space, our protocol does some operation on packet ( e.g. checks the packet authority and/or encrypts/decrypts it, ...) and then injects the packet upward to application layer or downward or simply drops it. The injected modified packet may not be as the same size of original one. So our requirements are: 1-Capture each packet which is coming inside or going outside the computer in Data-link Layer. 2-Create a copy of the packet and drop the original one. 3-Copy of packet must be available in user space to be manipulated by our protocol. 4-After manipulation in user space, inject encrypted/decrypted version of the privileged (copy of) packets to the network or upward to the application layer. And of course we want to have the minimum changes to be made on our current protocol. I tried raw sockets and libnetfilter_queue , but I didn't find a suitable solution (specially to let me inject packets upward to the application layer.) I need to know if it is possible to do this with libraries/interfaces currently available in user space or should I write a kernel module to do the above tasks for us? It is possible that I be overall in a mistake, so any guidance is pleased, Thanks in advance, Hamid. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
