From: John Fastabend <john.fastab...@gmail.com> Date: Fri, 23 Aug 2019 17:11:38 -0700
> An excerpt from netlink(7) man page, > > In multipart messages (multiple nlmsghdr headers with associated payload > in one byte stream) the first and all following headers have the > NLM_F_MULTI flag set, except for the last header which has the type > NLMSG_DONE. > > but, after (ee28906) there is a missing NLM_F_MULTI flag in the middle of a > FIB dump. The result is user space applications following above man page > excerpt may get confused and may stop parsing msg believing something went > wrong. > > In the golang netlink lib [0] the library logic stops parsing believing the > message is not a multipart message. Found this running Cilium[1] against > net-next while adding a feature to auto-detect routes. I noticed with > multiple route tables we no longer could detect the default routes on net > tree kernels because the library logic was not returning them. > > Fix this by handling the fib_dump_info_fnhe() case the same way the > fib_dump_info() handles it by passing the flags argument through the > call chain and adding a flags argument to rt_fill_info(). > > Tested with Cilium stack and auto-detection of routes works again. Also > annotated libs to dump netlink msgs and inspected NLM_F_MULTI and > NLMSG_DONE flags look correct after this. > > Note: In inet_rtm_getroute() pass rt_fill_info() '0' for flags the same > as is done for fib_dump_info() so this looks correct to me. > > [0] https://github.com/vishvananda/netlink/ > [1] https://github.com/cilium/ > > Fixes: ee28906fd7a14 ("ipv4: Dump route exceptions if requested") > Signed-off-by: John Fastabend <john.fastab...@gmail.com> Applied, thanks John.
