Subject: Re: [PATCH net-next v5 1/4] net/sched: Introduce action ct

From: Marcelo Ricardo Leitner <[email-masked]>
Date: Mon, 8 Jul 2019 10:42:08 -0300

On Mon, Jul 08, 2019 at 11:51:17AM +0300, Paul Blakey wrote:
..
> +static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
> +				   u8 family, u16 zone)
> +{
> +	enum ip_conntrack_info ctinfo;
> +	struct nf_conn *ct;
> +	int err = 0;
> +	bool frag;
> +
> +	/* Previously seen (loopback)? Ignore. */
> +	ct = nf_ct_get(skb, &ctinfo);
> +	if ((ct && !nf_ct_is_template(ct)) || ctinfo == IP_CT_UNTRACKED)
> +		return 0;
> +
> +	if (family == NFPROTO_IPV4)
> +		err = tcf_ct_ipv4_is_fragment(skb, &frag);
> +	else
> +		err = tcf_ct_ipv6_is_fragment(skb, &frag);
> +	if (err || !frag)
> +		return err;
> +
> +	skb_get(skb);
> +
> +	if (family == NFPROTO_IPV4) {
> +		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
> +
> +		memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
> +		local_bh_disable();
> +		err = ip_defrag(net, skb, user);
> +		local_bh_enable();
> +		if (err && err != -EINPROGRESS)
> +			goto out_free;
> +	} else { /* NFPROTO_IPV6 */
> +		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
> +
> +		memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
> +		err = nf_ct_frag6_gather(net, skb, user);

This doesn't build without IPv6 enabled.
ERROR: "nf_ct_frag6_gather" [net/sched/act_ct.ko] undefined!

We need to (copy and pasted):

@@ -179,7 +179,9 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
                local_bh_enable();
                if (err && err != -EINPROGRESS)
                        goto out_free;
-       } else { /* NFPROTO_IPV6 */
+       }
+#if IS_ENABLED(IPV6)
+       else { /* NFPROTO_IPV6 */
                enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;

                memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
@@ -187,6 +189,7 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
                if (err && err != -EINPROGRESS)
                        goto out_free;
        }
+#endif

        skb_clear_hash(skb);
        skb->ignore_df = 1;

> +		if (err && err != -EINPROGRESS)
> +			goto out_free;
> +	}
> +
> +	skb_clear_hash(skb);
> +	skb->ignore_df = 1;
> +	return err;
> +
> +out_free:
> +	kfree_skb(skb);
> +	return err;
> +}