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

[Cong Wang <cwang@twopensource.com>]

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On Fri, Sep 11, 2015 at 3:24 PM, Akshat Kakkar <akshat.1984@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!

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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])