2022-01-24 19:17:47

by Menglong Dong

Subject: [PATCH net-next 4/6] net: ipv4: use kfree_skb_reason() in ip_protocol_deliver_rcu()

From: Menglong Dong <[email protected]>

Replace kfree_skb() with kfree_skb_reason() in ip_protocol_deliver_rcu().
Following new drop reasons are introduced:

SKB_DROP_REASON_XFRM_POLICY
SKB_DROP_REASON_IP_NOPROTO

Signed-off-by: Menglong Dong <[email protected]>
---
include/linux/skbuff.h | 2 ++
include/trace/events/skb.h | 2 ++
net/ipv4/ip_input.c | 5 +++--
3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8942d32c0657..603f77ef2170 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -328,6 +328,8 @@ enum skb_drop_reason {
SKB_DROP_REASON_IP_RPFILTER,
SKB_DROP_REASON_EARLY_DEMUX,
SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST,
+ SKB_DROP_REASON_XFRM_POLICY,
+ SKB_DROP_REASON_IP_NOPROTO,
SKB_DROP_REASON_MAX,
};

diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 1dcdcc92cf08..e8369b8e8430 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -25,6 +25,8 @@
EM(SKB_DROP_REASON_EARLY_DEMUX, EARLY_DEMUX) \
EM(SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST, \
UNICAST_IN_L2_MULTICAST) \
+ EM(SKB_DROP_REASON_XFRM_POLICY, XFRM_POLICY) \
+ EM(SKB_DROP_REASON_IP_NOPROTO, IP_NOPROTO) \
EMe(SKB_DROP_REASON_MAX, MAX)

#undef EM
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index a4afb367cf02..376c96cfd5d1 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -196,7 +196,8 @@ void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol)
if (ipprot) {
if (!ipprot->no_policy) {
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
- kfree_skb(skb);
+ kfree_skb_reason(skb,
+ SKB_DROP_REASON_XFRM_POLICY);
return;
}
nf_reset_ct(skb);
@@ -215,7 +216,7 @@ void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int protocol)
icmp_send(skb, ICMP_DEST_UNREACH,
ICMP_PROT_UNREACH, 0);
}
- kfree_skb(skb);
+ kfree_skb_reason(skb, SKB_DROP_REASON_IP_NOPROTO);
} else {
__IP_INC_STATS(net, IPSTATS_MIB_INDELIVERS);
consume_skb(skb);
--
2.34.1

2022-01-26 15:27:34

by David Ahern

Subject: Re: [PATCH net-next 4/6] net: ipv4: use kfree_skb_reason() in ip_protocol_deliver_rcu()

On 1/24/22 6:15 AM, [email protected] wrote:
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 8942d32c0657..603f77ef2170 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -328,6 +328,8 @@ enum skb_drop_reason {

It would be worthwhile to document the meaning of these as you add them
-- long description of the enum.

> SKB_DROP_REASON_IP_RPFILTER,
> SKB_DROP_REASON_EARLY_DEMUX,
> SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST,

/* xfrm policy check failed */
> + SKB_DROP_REASON_XFRM_POLICY,

/* no support for IP protocol */
> + SKB_DROP_REASON_IP_NOPROTO,
> SKB_DROP_REASON_MAX,
> };
>


If the enum is 1:1 with an SNMP counter, just state that.

2022-01-26 16:20:50

by Menglong Dong

Subject: Re: [PATCH net-next 4/6] net: ipv4: use kfree_skb_reason() in ip_protocol_deliver_rcu()

On Wed, Jan 26, 2022 at 10:21 AM David Ahern <[email protected]> wrote:
>
> On 1/24/22 6:15 AM, [email protected] wrote:
> > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> > index 8942d32c0657..603f77ef2170 100644
> > --- a/include/linux/skbuff.h
> > +++ b/include/linux/skbuff.h
> > @@ -328,6 +328,8 @@ enum skb_drop_reason {
>
> It would be worthwhile to document the meaning of these as you add them
> -- long description of the enum.

Yeah, I realize it later. I'll complete these documents.

>
> > SKB_DROP_REASON_IP_RPFILTER,
> > SKB_DROP_REASON_EARLY_DEMUX,
> > SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST,
>
> /* xfrm policy check failed */
> > + SKB_DROP_REASON_XFRM_POLICY,
>
> /* no support for IP protocol */
> > + SKB_DROP_REASON_IP_NOPROTO,
> > SKB_DROP_REASON_MAX,
> > };
> >
>
>
> If the enum is 1:1 with an SNMP counter, just state that.