From 3a461da1d03e7a857edfa6a002040d07e118c639 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 15 Mar 2016 22:41:22 +0100 Subject: [PATCH] cls_bpf: reset class and reuse major in da 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 Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- 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 8dc84300ee79..425fe6a0eda3 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) -- 2.45.2