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authorAlexei Starovoitov <ast@plumgrid.com>2015-04-15 12:55:45 -0700
committerDavid S. Miller <davem@davemloft.net>2015-04-16 14:08:49 -0400
commita166151cbe33b53221c24259e4a7201064b3ba79 (patch)
treebbc94226f42d4baa1b6ee5203d58d55fa9a69919 /net/sched/act_bpf.c
parent51b5df886874816ff986fe66fe0d7b7eca9f6cd1 (diff)
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bpf: fix bpf helpers to use skb->mac_header relative offsets
For the short-term solution, lets fix bpf helper functions to use skb->mac_header relative offsets instead of skb->data in order to get the same eBPF programs with cls_bpf and act_bpf work on ingress and egress qdisc path. We need to ensure that mac_header is set before calling into programs. This is effectively the first option from below referenced discussion. More long term solution for LD_ABS|LD_IND instructions will be more intrusive but also more beneficial than this, and implemented later as it's too risky at this point in time. I.e., we plan to look into the option of moving skb_pull() out of eth_type_trans() and into netif_receive_skb() as has been suggested as second option. Meanwhile, this solution ensures ingress can be used with eBPF, too, and that we won't run into ABI troubles later. For dealing with negative offsets inside eBPF helper functions, we've implemented bpf_skb_clone_unwritable() to test for unwriteable headers. Reference: http://thread.gmane.org/gmane.linux.network/359129/focus=359694 Fixes: 608cd71a9c7c ("tc: bpf: generalize pedit action") Fixes: 91bc4822c3d6 ("tc: bpf: add checksum helpers") Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/act_bpf.c')
-rw-r--r--net/sched/act_bpf.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 4d2cede17468..dc6a2d324bd8 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -38,6 +38,9 @@ static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
struct tcf_bpf *prog = act->priv;
int action, filter_res;
+ if (unlikely(!skb_mac_header_was_set(skb)))
+ return TC_ACT_UNSPEC;
+
spin_lock(&prog->tcf_lock);
prog->tcf_tm.lastuse = jiffies;