The skb_mac_header_was_set() test in cls_bpf's and act_bpf's fast-path is
actually unnecessary and can be removed altogether. This was added by
commit a166151cbe33 ("bpf: fix bpf helpers to use skb->mac_header relative
offsets"), which was later on improved by 3431205e0397 ("bpf: make programs
see skb->data == L2 for ingress and egress"). We're always guaranteed to
have valid mac header at the time we invoke cls_bpf_classify() or tcf_bpf().
Reason is that since 6d1ccff62780 ("net: reset mac header in dev_start_xmit()")
we do skb_reset_mac_header() in __dev_queue_xmit() before we could call
into sch_handle_egress() or any subsequent enqueue. sch_handle_ingress()
always sees a valid mac header as well (things like skb_reset_mac_len()
would badly fail otherwise). Thus, drop the unnecessary test in classifier
and action case.
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Alexei Starovoitov <a...@kernel.org>
---
net/sched/act_bpf.c | 3 ---
net/sched/cls_bpf.c | 3 ---
2 files changed, 6 deletions(-)
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index bfa8707..78400de 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -44,9 +44,6 @@ static int tcf_bpf(struct sk_buff *skb, const struct
tc_action *act,
int action, filter_res;
bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
- if (unlikely(!skb_mac_header_was_set(skb)))
- return TC_ACT_UNSPEC;
-
tcf_lastuse_update(&prog->tcf_tm);
bstats_cpu_update(this_cpu_ptr(prog->common.cpu_bstats), skb);
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 4742f41..1d92d4d 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -83,9 +83,6 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct
tcf_proto *tp,
struct cls_bpf_prog *prog;
int ret = -1;
- if (unlikely(!skb_mac_header_was_set(skb)))
- return -1;
-
/* Needed here for accessing maps. */
rcu_read_lock();
list_for_each_entry_rcu(prog, &head->plist, link) {
--
1.9.3
