On Sun, May 3, 2020 at 11:29 PM Yonghong Song <yhs@xxxxxx> wrote:
>
> This patch added netlink and ipv6_route targets, using
> the same seq_ops (except show() and minor changes for stop())
> for /proc/net/{netlink,ipv6_route}.
>
> The net namespace for these targets are the current net
> namespace at file open stage, similar to
> /proc/net/{netlink,ipv6_route} reference counting
> the net namespace at seq_file open stage.
>
> Since module is not supported for now, ipv6_route is
> supported only if the IPV6 is built-in, i.e., not compiled
> as a module. The restriction can be lifted once module
> is properly supported for bpf_iter.
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
> fs/proc/proc_net.c | 19 +++++++++
> include/linux/proc_fs.h | 3 ++
> net/ipv6/ip6_fib.c | 65 +++++++++++++++++++++++++++++-
> net/ipv6/route.c | 27 +++++++++++++
> net/netlink/af_netlink.c | 87 +++++++++++++++++++++++++++++++++++++++-
> 5 files changed, 197 insertions(+), 4 deletions(-)
>
[...]
> int __init ip6_route_init(void)
> {
> int ret;
> @@ -6455,6 +6474,14 @@ int __init ip6_route_init(void)
> if (ret)
> goto out_register_late_subsys;
>
> +#if IS_BUILTIN(CONFIG_IPV6)
> +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
> + ret = bpf_iter_register();
> + if (ret)
> + goto out_register_late_subsys;
Seems like bpf_iter infra is missing unregistering API.
ip6_route_init(), if fails, undoes all the registrations, so probably
should also unregister ipv6_route target as well?
> +#endif
> +#endif
> +
> for_each_possible_cpu(cpu) {
> struct uncached_list *ul = per_cpu_ptr(&rt6_uncached_list, cpu);
>
[...]
> +static void netlink_seq_stop(struct seq_file *seq, void *v)
> +{
> + struct bpf_iter_meta meta;
> + struct bpf_prog *prog;
> +
> + if (!v) {
> + meta.seq = seq;
> + prog = bpf_iter_get_info(&meta, true);
> + if (prog)
> + netlink_prog_seq_show(prog, &meta, v);
nit: netlink_prog_seq_show() can return failure (from BPF program),
but you are not returning it. Given seq_file's stop is not supposed to
fail, you can explicitly cast result to (void)? I think it's done in
few other places in BPF code, when return result is explicitly
ignored.
> + }
> +
> + netlink_native_seq_stop(seq, v);
> +}
> +#else
[...]
