Motivation:
Linux kernel 4.11 introduced a new socket option,
TCP_FASTOPEN_CONNECT, that greatly simplifies making TCP Fast Open
connections on client side. Usually simply setting the flag before
connect() call is enough, no more changes are required.
Details can be found in kernel commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=19f6d3f3
Modifications:
TCP_FASTOPEN_CONNECT socket option was added to EpollChannelOption
class.
Result:
Netty clients can easily make TCP Fast Open connections. Simply
calling option(EpollChannelOption.TCP_FASTOPEN_CONNECT, true) in
client bootstrap is enough (given recent enough kernel).
If you are on Linux, you need additional development packages installed on your system, because you'll build the native transport.
Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.
Branches to look
Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.