Re: [fw filter]: Broken! fw mark based tc class selection not working

[Cong Wang]

On Fri, Sep 11, 2015 at 3:24 PM, Akshat Kakkar <akshat.1...@gmail.com> wrote:
> There is no handle with fw filter. That's the whole point is. If
> handle and class (flow id) is not specified, then whatever be the mark
> on the packet, its automatically set as flowid. So if mark is 0x10003,
> then this fw filter
>
> tc filter add dev eth0 parent 1:0 protocol ip fw
>
> will cause 0x10003 being set as classid I.e. 1:3.
>
>
> tc qdisc add dev eth0 root handle 1: htb
> tc class add dev eth0 parent 1: classid 1:a htb rate 1mbit
> tc class add dev eth0 parent 1: classid 1:b htb rate 1mbit
> tc class add dev eth0 parent 1: classid 1:c htb rate 1mbit
> tc filter add dev eth0 parent 1:0 protocol ip fw
>
> iptables -t mangle -I OUTPUT -o eth0 -p tcp -j MARK --set-mark 0x1000a
> iptables -t mangle -I OUTPUT -o eth0 -p icmp -j MARK --set-mark 0x1000b
> iptables -t mangle -I OUTPUT -o eth0 -p udp -j MARK --set-mark 0x1000c


Hmm, I didn't know that before either. Looks like my tp->init change
breaks it.

Could you try the following patch?

Thanks!

diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index 715e01e..b6394ab 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -34,6 +34,7 @@
 struct fw_head {
        u32                     mask;
        bool                    mask_set;
+       bool                    old_method;
        struct fw_filter __rcu  *ht[HTSIZE];
        struct rcu_head         rcu;
 };
@@ -65,7 +66,7 @@ static int fw_classify(struct sk_buff *skb, const struct 
tcf_proto *tp,
        int r;
        u32 id = skb->mark;
 
-       if (head != NULL) {
+       if (!head->old_method) {
                id &= head->mask;
 
                for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
@@ -120,6 +121,7 @@ static int fw_init(struct tcf_proto *tp)
        if (head == NULL)
                return -ENOBUFS;
 
+       head->old_method = true;
        head->mask_set = false;
        rcu_assign_pointer(tp->root, head);
        return 0;
@@ -302,6 +304,7 @@ static int fw_change(struct net *net, struct sk_buff 
*in_skb,
        if (!handle)
                return -EINVAL;
 
+       head->old_method = false;
        if (!head->mask_set) {
                head->mask = 0xFFFFFFFF;
                if (tb[TCA_FW_MASK])