Commit 16085e48 authored by Victor Nogueira's avatar Victor Nogueira Committed by David S. Miller
Browse files

net/sched: act_mirred: Create function tcf_mirred_to_dev and improve readability 



As a preparation for adding block ID to mirred, separate the part of
mirred that redirect/mirrors to a dev into a specific function so that it
can be called by blockcast for each dev.

Also improve readability. Eg. rename use_reinsert to dont_clone and skb2
to skb_to_send.

Co-developed-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Co-developed-by: default avatarPedro Tammela <pctammela@mojatatu.com>
Signed-off-by: default avatarPedro Tammela <pctammela@mojatatu.com>
Signed-off-by: default avatarVictor Nogueira <victor@mojatatu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a7042cf8

net/sched/act_mirred.c

+72 −57
Original line number Diff line number Diff line
@@ -225,48 +225,26 @@ static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) 
	return err;

}



TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,

				     const struct tc_action *a,

				     struct tcf_result *res)

static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m,

			     struct net_device *dev,

			     const bool m_mac_header_xmit, int m_eaction,

			     int retval)

{

	struct tcf_mirred *m = to_mirred(a);

	struct sk_buff *skb2 = skb;

	bool m_mac_header_xmit;

	struct net_device *dev;

	unsigned int nest_level;

	int retval, err = 0;

	bool use_reinsert;

	struct sk_buff *skb_to_send = skb;

	bool want_ingress;

	bool is_redirect;

	bool expects_nh;

	bool at_ingress;

	int m_eaction;

	bool dont_clone;

	int mac_len;

	bool at_nh;

	int err;



	nest_level = __this_cpu_inc_return(mirred_nest_level);

	if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {

		net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",

				     netdev_name(skb->dev));

		__this_cpu_dec(mirred_nest_level);

		return TC_ACT_SHOT;

	}



	tcf_lastuse_update(&m->tcf_tm);

	tcf_action_update_bstats(&m->common, skb);



	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);

	m_eaction = READ_ONCE(m->tcfm_eaction);

	retval = READ_ONCE(m->tcf_action);

	dev = rcu_dereference_bh(m->tcfm_dev);

	if (unlikely(!dev)) {

		pr_notice_once("tc mirred: target device is gone\n");

		goto out;

	}



	is_redirect = tcf_mirred_is_act_redirect(m_eaction);

	if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {

		net_notice_ratelimited("tc mirred to Houston: device %s is down\n",

				       dev->name);

		err = -ENODEV;

		goto out;

	}
@@ -274,61 +252,98 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, 
	 * since we can't easily detect the clsact caller, skip clone only for

	 * ingress - that covers the TC S/W datapath.

	 */

	is_redirect = tcf_mirred_is_act_redirect(m_eaction);

	at_ingress = skb_at_tc_ingress(skb);

	use_reinsert = at_ingress && is_redirect &&

	dont_clone = skb_at_tc_ingress(skb) && is_redirect &&

		tcf_mirred_can_reinsert(retval);

	if (!use_reinsert) {

		skb2 = skb_clone(skb, GFP_ATOMIC);

		if (!skb2)

	if (!dont_clone) {

		skb_to_send = skb_clone(skb, GFP_ATOMIC);

		if (!skb_to_send) {

			err =  -ENOMEM;

			goto out;

		}

	}



	want_ingress = tcf_mirred_act_wants_ingress(m_eaction);



	/* All mirred/redirected skbs should clear previous ct info */

	nf_reset_ct(skb2);

	nf_reset_ct(skb_to_send);

	if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */

		skb_dst_drop(skb2);

		skb_dst_drop(skb_to_send);



	expects_nh = want_ingress || !m_mac_header_xmit;

	at_nh = skb->data == skb_network_header(skb);

	if (at_nh != expects_nh) {

		mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :

		mac_len = at_ingress ? skb->mac_len :

			  skb_network_offset(skb);

		if (expects_nh) {

			/* target device/action expect data at nh */

			skb_pull_rcsum(skb2, mac_len);

			skb_pull_rcsum(skb_to_send, mac_len);

		} else {

			/* target device/action expect data at mac */

			skb_push_rcsum(skb2, mac_len);

			skb_push_rcsum(skb_to_send, mac_len);

		}

	}



	skb2->skb_iif = skb->dev->ifindex;

	skb2->dev = dev;

	skb_to_send->skb_iif = skb->dev->ifindex;

	skb_to_send->dev = dev;



	/* mirror is always swallowed */

	if (is_redirect) {

		skb_set_redirected(skb2, skb2->tc_at_ingress);

		if (skb == skb_to_send)

			retval = TC_ACT_CONSUMED;



		/* let's the caller reinsert the packet, if possible */

		if (use_reinsert) {

			err = tcf_mirred_forward(want_ingress, skb);

			if (err)

				tcf_action_inc_overlimit_qstats(&m->common);

			__this_cpu_dec(mirred_nest_level);

			return TC_ACT_CONSUMED;

		}

		skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress);



		err = tcf_mirred_forward(want_ingress, skb_to_send);

	} else {

		err = tcf_mirred_forward(want_ingress, skb_to_send);

	}



	err = tcf_mirred_forward(want_ingress, skb2);

	if (err) {

out:

		tcf_action_inc_overlimit_qstats(&m->common);

		if (tcf_mirred_is_act_redirect(m_eaction))

		if (is_redirect)

			retval = TC_ACT_SHOT;

	}



	return retval;

}



TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb,

				     const struct tc_action *a,

				     struct tcf_result *res)

{

	struct tcf_mirred *m = to_mirred(a);

	int retval = READ_ONCE(m->tcf_action);

	unsigned int nest_level;

	bool m_mac_header_xmit;

	struct net_device *dev;

	int m_eaction;



	nest_level = __this_cpu_inc_return(mirred_nest_level);

	if (unlikely(nest_level > MIRRED_NEST_LIMIT)) {

		net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",

				     netdev_name(skb->dev));

		retval = TC_ACT_SHOT;

		goto dec_nest_level;

	}



	tcf_lastuse_update(&m->tcf_tm);

	tcf_action_update_bstats(&m->common, skb);



	dev = rcu_dereference_bh(m->tcfm_dev);

	if (unlikely(!dev)) {

		pr_notice_once("tc mirred: target device is gone\n");

		tcf_action_inc_overlimit_qstats(&m->common);

		goto dec_nest_level;

	}



	m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);

	m_eaction = READ_ONCE(m->tcfm_eaction);



	retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction,

				   retval);



dec_nest_level:

	__this_cpu_dec(mirred_nest_level);



	return retval;