From: Martin KaFai Lau <kafai@xxxxxx>
Date: Wed, 18 Nov 2020 16:11:54 -0800
> On Tue, Nov 17, 2020 at 06:40:21PM +0900, Kuniyuki Iwashima wrote:
> > We will call sock_reuseport.prog for socket migration in the next commit,
> > so the eBPF program has to know which listener is closing in order to
> > select the new listener.
> >
> > Currently, we can get a unique ID for each listener in the userspace by
> > calling bpf_map_lookup_elem() for BPF_MAP_TYPE_REUSEPORT_SOCKARRAY map.
> > This patch exposes the ID to the eBPF program.
> >
> > Reviewed-by: Benjamin Herrenschmidt <benh@xxxxxxxxxx>
> > Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
> > ---
> > include/linux/bpf.h | 1 +
> > include/uapi/linux/bpf.h | 1 +
> > net/core/filter.c | 8 ++++++++
> > tools/include/uapi/linux/bpf.h | 1 +
> > 4 files changed, 11 insertions(+)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 581b2a2e78eb..c0646eceffa2 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -1897,6 +1897,7 @@ struct sk_reuseport_kern {
> > u32 hash;
> > u32 reuseport_id;
> > bool bind_inany;
> > + u64 cookie;
> > };
> > bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
> > struct bpf_insn_access_aux *info);
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 162999b12790..3fcddb032838 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -4403,6 +4403,7 @@ struct sk_reuseport_md {
> > __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
> > __u32 bind_inany; /* Is sock bound to an INANY address? */
> > __u32 hash; /* A hash of the packet 4 tuples */
> > + __u64 cookie; /* ID of the listener in map */
> Instead of only adding the cookie of a sk, lets make the sk pointer available:
>
> __bpf_md_ptr(struct bpf_sock *, sk);
>
> and then use the BPF_FUNC_get_socket_cookie to get the cookie.
>
> Other fields of the sk can also be directly accessed too once
> the sk pointer is available.
Oh, I did not know BPF_FUNC_get_socket_cookie.
I will add the sk pointer and use the helper function in the next spin!
Thank you.
