Virtual Transport Layer (VTL)

Virtual Transport Layer, a protocol deployment management system aiming (1) to dynamically deploy protocol mechanisms/components, in order (2) to ensure optimal data moving between end-points.

I am spending time bettering the implementation. Until now the focus has been on the correctness rather than performance. I will keep correctness, but I will improve performance, especially in light of practical experience with applications. Suggestions are welcome.

Notice

VTL and its components have been tested on Ubuntu 20.04 LTS.

Step 1: Compile and install VTL's customized linux kernel

git clone https://github.com/elfadel/vtl_kern.git linux-vtl
cd linux-vtl
cp -v /boot/config-$(uname -r) .config
make olddefconfig
scripts/config --disable SYSTEM_TRUSTED_KEYS
make -j $(nproc)
sudo make INSTALL_MOD_STRIP=1 modules_install
sudo make headers_install
sudo make install

Reboot, and make sure to boot on linux v5.3.5+.

Step 2: Configure eBPF/XDP environment

sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
LLVM_VERSION=14 # match the actual version of the clang installed on the system
sudo update-alternatives --install /usr/bin/clang clang "/usr/bin/clang-$LLVM_VERSION" 100
sudo update-alternatives --install /usr/bin/clang++ clang++ "/usr/bin/clang++-$LLVM_VERSION" 100
sudo update-alternatives --install /usr/bin/llc llc "/usr/bin/llc-$LLVM_VERSION" 100
sudo update-alternatives --install /usr/bin/llvm-mc llvm-mc "/usr/bin/llvm-mc-$LLVM_VERSION" 50

Step 3: Compile and build VTL

git clone --recurse-submodules https://github.com/elfadel/vtl.git
sudo apt install libpcap-dev gcc-multilib

# configure nDPI deps
cd deps/nDPI
sudo apt ins	tall -y autoconf libtool libjson-c-dev
./autogen.sh
./configure
make
cd ../..

# compile VTL
mkdir bin
make

Test and run Hooker:

> Hooker contains two programs:

• The daemon in /hooker folder, that is created with a make call. It is user prog part of Hooker.
• The kernel prog part that contains mainly two eBPF progs: sock_ops, to monitor specific or a set of TCP applications, and sk_msg, to redirect the monitored applications' data.

> First: build and launch (deploy) kernel prog part:

cd bin
sudo ./vtl_ui

# Follow the instructions and make choices.

> Second: start user daemon

$ cd hooker
$ make 
$ sudo ./hk-daemon <IPPROTO> <HOST_MODE>

IPPROTO: this argument is an integer and is used to indicate which protocol should be used to replace TCP. Indeed, VTL allows the user to manually fix the substitution protocol by specifying one of the supported IP protocol (list below) or let this task to VTL by specified 253 (default) as the argument value.

List of substitution protocol supported by VTL and their corresponding IP number:

Protocol	IP number [IANA]
UDP	17
UDPLite	136
DCCP	33
SCTP	132
QUIC	142 (conventional in VTL)
VTL	253 (conventional in VTL)

HOST_MODE: a string to indicate if the hooker daemon will hook either a TCP client or a TCP server.

> Finally, just run your TCP applications.