The branch net-next has accepted a change that removes support for the network protocol DCCP (Datagram Control Protocol) from the Linux kernel. However, support for Netfilter modules for filtering DCCP packets will still be available. The DCCP protocol was standardized and integrated into the kernel back in 2006 with the expectation of enhancing streaming and Internet telephony efficiency in congested networks. Unfortunately, the protocol did not gain widespread adoption and demand.
The DCCP code in the kernel has been untouched for five years, with recent changes mainly focused on correcting issues related to API refactoring. A few years ago, the Multipath DCCP project attempted to enhance the DCCP protocol within the kernel. However, some code from this project remains proprietary. The developer had plans to open-source the proprietary code, merge the changes into the main kernel, and take over the maintenance of DCCP within the Linux kernel. Unfortunately, the developer has been unreachable for a number of years.
The removal of DCCP from the Linux kernel will eliminate obstacles hindering improvements to the Inet_connection_Sock data structure, specifically in enhancing the efficiency of the TCP stack. Currently, the Inet_connection_Sock structure is shared between TCP and DCCP, preventing TCP optimizations without altering DCCP code. Restructuring the Inet_connection_Sock will allow for more efficient processor cache utilization for accelerated packet processing in established TCP connections (TCP Fastpath), ultimately enhancing overall network performance.