bpf: Enable BPF_PROG_TYPE_SK_REUSEPORT bpf prog in reuseport selection

This patch allows a BPF_PROG_TYPE_SK_REUSEPORT bpf prog to select a
SO_REUSEPORT sk from a BPF_MAP_TYPE_REUSEPORT_ARRAY introduced in
the earlier patch.  "bpf_run_sk_reuseport()" will return -ECONNREFUSED
when the BPF_PROG_TYPE_SK_REUSEPORT prog returns SK_DROP.
The callers, in inet[6]_hashtable.c and ipv[46]/udp.c, are modified to
handle this case and return NULL immediately instead of continuing the
sk search from its hashtable.

It re-uses the existing SO_ATTACH_REUSEPORT_EBPF setsockopt to attach
BPF_PROG_TYPE_SK_REUSEPORT.  The "sk_reuseport_attach_bpf()" will check
if the attaching bpf prog is in the new SK_REUSEPORT or the existing
SOCKET_FILTER type and then check different things accordingly.

One level of "__reuseport_attach_prog()" call is removed.  The
"sk_unhashed() && ..." and "sk->sk_reuseport_cb" tests are pushed
back to "reuseport_attach_prog()" in sock_reuseport.c.  sock_reuseport.c
seems to have more knowledge on those test requirements than filter.c.
In "reuseport_attach_prog()", after new_prog is attached to reuse->prog,
the old_prog (if any) is also directly freed instead of returning the
old_prog to the caller and asking the caller to free.

The sysctl_optmem_max check is moved back to the
"sk_reuseport_attach_filter()" and "sk_reuseport_attach_bpf()".
As of other bpf prog types, the new BPF_PROG_TYPE_SK_REUSEPORT is only
bounded by the usual "bpf_prog_charge_memlock()" during load time
instead of bounded by both bpf_prog_charge_memlock and sysctl_optmem_max.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Martin KaFai Lau
2018-08-08 01:01:26 -07:00
committed by Daniel Borkmann
parent 2dbb9b9e6d
commit 8217ca653e
8 changed files with 107 additions and 58 deletions

View File

@@ -191,7 +191,7 @@ struct sock *inet6_lookup_listener(struct net *net,
saddr, sport, daddr, hnum,
dif, sdif);
if (result)
return result;
goto done;
/* Lookup lhash2 with in6addr_any */
@@ -200,9 +200,10 @@ struct sock *inet6_lookup_listener(struct net *net,
if (ilb2->count > ilb->count)
goto port_lookup;
return inet6_lhash2_lookup(net, ilb2, skb, doff,
saddr, sport, daddr, hnum,
dif, sdif);
result = inet6_lhash2_lookup(net, ilb2, skb, doff,
saddr, sport, daddr, hnum,
dif, sdif);
goto done;
port_lookup:
sk_for_each(sk, &ilb->head) {
@@ -214,12 +215,15 @@ port_lookup:
result = reuseport_select_sock(sk, phash,
skb, doff);
if (result)
return result;
goto done;
}
result = sk;
hiscore = score;
}
}
done:
if (unlikely(IS_ERR(result)))
return NULL;
return result;
}
EXPORT_SYMBOL_GPL(inet6_lookup_listener);