On Mon, Jun 22, 2020 at 5:38 PM Yonghong Song <yhs@xxxxxx> wrote:
>
> In my VM, I got identical result compared to /proc/net/{tcp,tcp6}.
> For tcp6:
> $ cat /proc/net/tcp6
> sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
> 0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000001 00000000 0 0 17955 1 000000003eb3102e 100 0 0 10 0
>
> $ cat /sys/fs/bpf/p1
> sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
> 0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 17955 1 000000003eb3102e 100 0 0 10 0
>
> For tcp:
> $ cat /proc/net/tcp
> sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
> 0: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 2666 1 000000007152e43f 100 0 0 10 0
> $ cat /sys/fs/bpf/p2
> sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode
> 1: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 2666 1 000000007152e43f 100 0 0 10 0
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
Looks reasonable, to the extent possible ;)
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> tools/testing/selftests/bpf/progs/bpf_iter.h | 15 ++
> .../selftests/bpf/progs/bpf_iter_tcp4.c | 235 ++++++++++++++++
> .../selftests/bpf/progs/bpf_iter_tcp6.c | 250 ++++++++++++++++++
> 3 files changed, 500 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
>
[...]
> +static int hlist_unhashed_lockless(const struct hlist_node *h)
> +{
> + return !(h->pprev);
> +}
> +
> +static int timer_pending(const struct timer_list * timer)
> +{
> + return !hlist_unhashed_lockless(&timer->entry);
> +}
> +
> +extern unsigned CONFIG_HZ __kconfig __weak;
Why the __weak? We expect to have /proc/kconfig.gz in other tests
anyway? __weak will make CONFIG_HZ to be a zero and you'll get a bunch
of divisions by zero.
> +
> +#define USER_HZ 100
> +#define NSEC_PER_SEC 1000000000ULL
> +static clock_t jiffies_to_clock_t(unsigned long x)
> +{
> + /* The implementation here tailored to a particular
> + * setting of USER_HZ.
> + */
> + u64 tick_nsec = (NSEC_PER_SEC + CONFIG_HZ/2) / CONFIG_HZ;
> + u64 user_hz_nsec = NSEC_PER_SEC / USER_HZ;
> +
> + if ((tick_nsec % user_hz_nsec) == 0) {
> + if (CONFIG_HZ < USER_HZ)
> + return x * (USER_HZ / CONFIG_HZ);
> + else
> + return x / (CONFIG_HZ / USER_HZ);
> + }
> + return x * tick_nsec/user_hz_nsec;
> +}
> +
[...]
> + if (sk_common->skc_family != AF_INET)
> + return 0;
> +
> + tp = bpf_skc_to_tcp_sock(sk_common);
> + if (tp) {
> + return dump_tcp_sock(seq, tp, uid, seq_num);
> + }
nit: unnecessary {}
> +
> + tw = bpf_skc_to_tcp_timewait_sock(sk_common);
> + if (tw)
> + return dump_tw_sock(seq, tw, uid, seq_num);
> +
> + req = bpf_skc_to_tcp_request_sock(sk_common);
> + if (req)
> + return dump_req_sock(seq, req, uid, seq_num);
> +
> + return 0;
> +}
[...]
> +static int timer_pending(const struct timer_list * timer)
> +{
> + return !hlist_unhashed_lockless(&timer->entry);
> +}
> +
> +extern unsigned CONFIG_HZ __kconfig __weak;
same about __weak here
> +
> +#define USER_HZ 100
> +#define NSEC_PER_SEC 1000000000ULL
> +static clock_t jiffies_to_clock_t(unsigned long x)
> +{
> + /* The implementation here tailored to a particular
> + * setting of USER_HZ.
> + */
> + u64 tick_nsec = (NSEC_PER_SEC + CONFIG_HZ/2) / CONFIG_HZ;
> + u64 user_hz_nsec = NSEC_PER_SEC / USER_HZ;
> +
> + if ((tick_nsec % user_hz_nsec) == 0) {
> + if (CONFIG_HZ < USER_HZ)
> + return x * (USER_HZ / CONFIG_HZ);
> + else
> + return x / (CONFIG_HZ / USER_HZ);
> + }
> + return x * tick_nsec/user_hz_nsec;
> +}
nit: jiffies_to_clock_t() implementation looks like an overkill for
this use case... Would it be just `x / CONFIG_HZ * NSEC_PER_SEC` with
some potential rounding error?
> +
> +static clock_t jiffies_delta_to_clock_t(long delta)
> +{
> + if (delta <= 0)
> + return 0;
> +
> + return jiffies_to_clock_t(delta);
> +}
> +
[...]
