Hi Willem,
overall I think the series looks great, thanks for working on it!
On 12/28/2016 08:13 PM, Willem de Bruijn wrote:
From: Willem de Bruijn <will...@google.com>
Field tc_at is used only within tc actions to distinguish ingress from
egress processing. A single bit is sufficient for this purpose. Set it
within tc_classify to make the scope clear and to avoid the need to
clear it in skb_reset_tc.
Signed-off-by: Willem de Bruijn <will...@google.com>
---
include/linux/skbuff.h | 3 ++-
include/net/sch_generic.h | 3 +--
net/core/dev.c | 6 +-----
net/sched/act_mirred.c | 12 ++++++------
net/sched/sch_api.c | 1 +
5 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f738d09..fab3f87 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -590,6 +590,7 @@ static inline bool skb_mstamp_after(const struct skb_mstamp
*t1,
* @fclone: skbuff clone status
* @ipvs_property: skbuff is owned by ipvs
* @tc_skip_classify: do not classify packet. set by IFB device
+ * @tc_at_ingress: used within tc_classify to distinguish in/egress
* @peeked: this packet has been seen already, so stats have been
* done for it, don't do them again
* @nf_trace: netfilter packet trace flag
@@ -751,7 +752,7 @@ struct sk_buff {
#endif
#ifdef CONFIG_NET_CLS_ACT
__u8 tc_skip_classify:1;
- __u8 tc_at:2;
+ __u8 tc_at_ingress:1;
__u8 tc_from:2;
#endif
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index f80dba5..4bd6d53 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -412,7 +412,6 @@ int skb_do_redirect(struct sk_buff *);
static inline void skb_reset_tc(struct sk_buff *skb)
{
#ifdef CONFIG_NET_CLS_ACT
- skb->tc_at = 0;
skb->tc_from = 0;
#endif
}
@@ -420,7 +419,7 @@ static inline void skb_reset_tc(struct sk_buff *skb)
static inline bool skb_at_tc_ingress(const struct sk_buff *skb)
{
#ifdef CONFIG_NET_CLS_ACT
- return skb->tc_at & AT_INGRESS;
+ return skb->tc_at_ingress;
#else
return false;
#endif
diff --git a/net/core/dev.c b/net/core/dev.c
index 25620cf..90833fdf 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3153,9 +3153,7 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct
net_device *dev)
if (!cl)
return skb;
- /* skb->tc_at and qdisc_skb_cb(skb)->pkt_len were already set
- * earlier by the caller.
- */
+ /* qdisc_skb_cb(skb)->pkt_len was already set by the caller. */
qdisc_bstats_cpu_update(cl->q, skb);
switch (tc_classify(skb, cl, &cl_res, false)) {
@@ -3320,7 +3318,6 @@ static int __dev_queue_xmit(struct sk_buff *skb, void
*accel_priv)
qdisc_pkt_len_init(skb);
#ifdef CONFIG_NET_CLS_ACT
- skb->tc_at = AT_EGRESS;
# ifdef CONFIG_NET_EGRESS
if (static_key_false(&egress_needed)) {
skb = sch_handle_egress(skb, &rc, dev);
@@ -3916,7 +3913,6 @@ sch_handle_ingress(struct sk_buff *skb, struct
packet_type **pt_prev, int *ret,
}
qdisc_skb_cb(skb)->pkt_len = skb->len;
- skb->tc_at = AT_INGRESS;
qdisc_bstats_cpu_update(cl->q, skb);
switch (tc_classify(skb, cl, &cl_res, false)) {
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 8543279..e832c62 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -39,15 +39,15 @@ static bool tcf_mirred_is_act_redirect(int action)
return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
}
-static u32 tcf_mirred_act_direction(int action)
+static bool tcf_mirred_act_wants_ingress(int action)
{
switch (action) {
case TCA_EGRESS_REDIR:
case TCA_EGRESS_MIRROR:
- return AT_EGRESS;
+ return false;
case TCA_INGRESS_REDIR:
case TCA_INGRESS_MIRROR:
- return AT_INGRESS;
+ return true;
default:
BUG();
}
@@ -198,7 +198,7 @@ static int tcf_mirred(struct sk_buff *skb, const struct
tc_action *a,
* and devices expect a mac header on xmit, then mac push/pull is
* needed.
*/
- if (skb->tc_at != tcf_mirred_act_direction(m_eaction) &&
+ if (skb_at_tc_ingress(skb) != tcf_mirred_act_wants_ingress(m_eaction) &&
m_mac_header_xmit) {
if (!skb_at_tc_ingress(skb)) {
/* caught at egress, act ingress: pull mac */
@@ -212,11 +212,11 @@ static int tcf_mirred(struct sk_buff *skb, const struct
tc_action *a,
/* mirror is always swallowed */
if (tcf_mirred_is_act_redirect(m_eaction))
- skb2->tc_from = skb2->tc_at;
+ skb2->tc_from = skb_at_tc_ingress(skb) ? AT_INGRESS : AT_EGRESS;
skb2->skb_iif = skb->dev->ifindex;
skb2->dev = dev;
- if (tcf_mirred_act_direction(m_eaction) & AT_EGRESS)
+ if (!tcf_mirred_act_wants_ingress(m_eaction))
err = dev_queue_xmit(skb2);
else
err = netif_receive_skb(skb2);
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ef53ede..be4e18d 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1865,6 +1865,7 @@ int tc_classify(struct sk_buff *skb, const struct
tcf_proto *tp,
const struct tcf_proto *old_tp = tp;
int limit = 0;
+ skb->tc_at_ingress = !!(tp && tp->q->flags & TCQ_F_INGRESS);
I'd prefer if skb->tc_at_ingress is set directly to 0/1 in sch_handle_ingress()
and __dev_queue_xmit() as we do right now, this would avoid above tests in fast
path and it would also avoid to set the same thing in tc_classify() multiple
times f.e. on egress path walking through multiple qdiscs. I don't see anything
in layers above tc that would read it and expect an AT_STACK-like equivalent.
skb_reset_tc() could thus still remain as you have above in fast-path like
__netif_receive_skb_core().
reclassify:
#endif
for (; tp; tp = rcu_dereference_bh(tp->next)) {
Thanks,
Daniel
