ZPTCPIPStack is based on lwIP 2.0.2 released with a major modification, designed to work with the NetworkExtension framework and provides asynchronous tcp control interface like socket. Now, it just support IPv4.
ZPTCPIPStack is Carthage compatible. To include it add the following line to your Cartfile
github "zapcannon87/ZPTCPIPStack" "master"
there is a problem with directly integrating ZPTCPIPStack into project using Carthage. I'm fixing it. alternative you can refer the files into a project's inner framework.