There are two issues with the current code. First one is that we need
to set res->class to 0 in case we use non-default classid matching.
This is important for the case where cls_bpf was initially set up with
an optional binding to a default class with tcf_bind_filter(), where
the underlying qdisc implements bind_tcf() that fills res->class and
tests for it later on when doing the classification. Convention for
these cases is that after tc_classify() was called, such qdiscs (atm,
drr, qfq, cbq, hfsc, htb) first test class, and if 0, then they lookup
based on classid.
Second, there's a bug with da mode, where res->classid is only assigned
a 16 bit minor, but it needs to expand to the full 32 bit major/minor
combination instead, therefore we need to expand with the bound major.
This is fine as classes belonging to a classful qdisc must share the
same major.
Fixes: 045efa82ff56 ("cls_bpf: introduce integrated actions")
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Alexei Starovoitov <a...@kernel.org>
---
net/sched/cls_bpf.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index 8dc8430..425fe6a 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -103,8 +103,9 @@ static int cls_bpf_classify(struct sk_buff *skb, const
struct tcf_proto *tp,
}
if (prog->exts_integrated) {
- res->class = prog->res.class;
- res->classid = qdisc_skb_cb(skb)->tc_classid;
+ res->class = 0;
+ res->classid = TC_H_MAJ(prog->res.classid) |
+ qdisc_skb_cb(skb)->tc_classid;
ret = cls_bpf_exec_opcode(filter_res);
if (ret == TC_ACT_UNSPEC)
@@ -114,10 +115,12 @@ static int cls_bpf_classify(struct sk_buff *skb, const
struct tcf_proto *tp,
if (filter_res == 0)
continue;
-
- *res = prog->res;
- if (filter_res != -1)
+ if (filter_res != -1) {
+ res->class = 0;
res->classid = filter_res;
+ } else {
+ *res = prog->res;
+ }
ret = tcf_exts_exec(skb, &prog->exts, res);
if (ret < 0)
--
1.9.3
