We have a number of Makefile tests for the presence of various fields in tcp_info. However that only tells us if they're present in the kernel headers against which we're compiling, not whether they're available in the kernel we're running on. For anything outside the earliest forms of TCP_INFO (as described in netinet/tcp.h and shared with BSD), we should verify at runtime if the kernel is returning that information. This was supposed to be leading into improved handling of lazily calling TCP_INFO, but I hit additional complications there, so I've postponed it. Might as well get these bits merged, though. David Gibson (2): tcp: Generalise probing for tcpi_snd_wnd field tcp: Use runtime tests for TCP_INFO fields tcp.c | 97 +++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 57 insertions(+), 40 deletions(-) -- 2.47.0