[PATCH 6.6 238/299] net/sched: act_mirred: Create function tcf_mirred_to_dev and improve readability

Greg Kroah-Hartman
2024-02-27T13:57:50Z

From: Victor Nogueira <victor@mojatatu.com>

[ Upstream commit 16085e48cb48aeb50a1178dc276747749910b0f2 ]

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: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Co-developed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 52f671db1882 ("net/sched: act_mirred: use the backlog for mirred ingress")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sched/act_mirred.c | 129 +++++++++++++++++++++++------------------
1 file changed, 72 insertions(+), 57 deletions(-)

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 0a711c184c29b..6f2544c1e3961 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -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 &&
- tcf_mirred_can_reinsert(retval);
- if (!use_reinsert) {
- skb2 = skb_clone(skb, GFP_ATOMIC);
- if (!skb2)
+ dont_clone = skb_at_tc_ingress(skb) && is_redirect &&
+ tcf_mirred_can_reinsert(retval);
+ 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);
-
- /* 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;
- }
+ if (skb == skb_to_send)
+ retval = 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;
--
2.43.0