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Chenbo Feng says: ==================== New getsockopt option to retrieve socket cookie In the current kernel socket cookie implementation, there is no simple and direct way to retrieve the socket cookie based on file descriptor. A process mat need to get it from sock fd if it want to correlate with sock_diag output or use a bpf map with new socket cookie function. If userspace wants to receive the socket cookie for a given socket fd, it must send a SOCK_DIAG_BY_FAMILY dump request and look for the 5-tuple. This is slow and can be ambiguous in the case of sockets that have the same 5-tuple (e.g., tproxy / transparent sockets, SO_REUSEPORT sockets, etc.). As shown in the example program. The xt_eBPF program is using socket cookie to record the network traffics statistics and with the socket cookie retrieved by getsockopt. The program can directly access to a specific socket data without scanning the whole bpf map. ==================== Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.