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Merge branch 'ip-neigh-skb-reason'

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Menglong Dong says:

====================
net: use kfree_skb_reason() for ip/neighbour

In the series "net: use kfree_skb_reason() for ip/udp packet receive",
reasons for skb drops are added to the packet receive process of IP
layer. Link:

https://lore.kernel.org/netdev/20220205074739.543606-1-imagedong@tencent.com/

And in the first patch of this series, skb drop reasons are added to
the packet egress path of IP layer. As kfree_skb() is not used frequent,
I commit these changes at once and didn't create a patch for every
functions that involed. Following functions are handled:

__ip_queue_xmit()
ip_finish_output()
ip_mc_finish_output()
ip6_output()
ip6_finish_output()
ip6_finish_output2()

Following new drop reasons are introduced (what they mean can be seen
in the document of them):

SKB_DROP_REASON_IP_OUTNOROUTES
SKB_DROP_REASON_BPF_CGROUP_EGRESS
SKB_DROP_REASON_IPV6DISABLED
SKB_DROP_REASON_NEIGH_CREATEFAIL

In the 2th and 3th patches, kfree_skb_reason() is used in neighbour
subsystem instead of kfree_skb(). __neigh_event_send() and
arp_error_report() are involed, and following new drop reasons are
introduced:

SKB_DROP_REASON_NEIGH_FAILED
SKB_DROP_REASON_NEIGH_QUEUEFULL
SKB_DROP_REASON_NEIGH_DEAD

Changes since v2:
- fix typo in the 1th patch of 'SKB_DROP_REASON_IPV6DSIABLED' reported
  by Roman

Changes since v1:
- introduce SKB_DROP_REASON_NEIGH_CREATEFAIL for some path in the 1th
  patch
- introduce SKB_DROP_REASON_NEIGH_DEAD in the 2th patch
- simplify the document for the new drop reasons, as David Ahern
  suggested
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2022-02-26 12:53:59 +00:00
commit 4aaa489538
6 changed files with 33 additions and 11 deletions
include
linux
skbuff.h
trace/events
skb.h
net
core
neighbour.c
ipv4
arp.cip_output.c
ipv6
ip6_output.c

14
include/linux/skbuff.h
View File

@ -380,6 +380,20 @@ enum skb_drop_reason {
* the ofo queue, corresponding to
* LINUX_MIB_TCPOFOMERGE
*/
SKB_DROP_REASON_IP_OUTNOROUTES, /* route lookup failed */
SKB_DROP_REASON_BPF_CGROUP_EGRESS, /* dropped by
* BPF_PROG_TYPE_CGROUP_SKB
* eBPF program
*/
SKB_DROP_REASON_IPV6DISABLED, /* IPv6 is disabled on the device */
SKB_DROP_REASON_NEIGH_CREATEFAIL, /* failed to create neigh
* entry
*/
SKB_DROP_REASON_NEIGH_FAILED, /* neigh entry in failed state */
SKB_DROP_REASON_NEIGH_QUEUEFULL, /* arp_queue for neigh
* entry is full
*/
SKB_DROP_REASON_NEIGH_DEAD, /* neigh entry is dead */
SKB_DROP_REASON_MAX,
};

8
include/trace/events/skb.h
View File

@ -37,6 +37,14 @@
EM(SKB_DROP_REASON_TCP_OLD_DATA, TCP_OLD_DATA) \
EM(SKB_DROP_REASON_TCP_OVERWINDOW, TCP_OVERWINDOW) \
EM(SKB_DROP_REASON_TCP_OFOMERGE, TCP_OFOMERGE) \
EM(SKB_DROP_REASON_IP_OUTNOROUTES, IP_OUTNOROUTES) \
EM(SKB_DROP_REASON_BPF_CGROUP_EGRESS, \
BPF_CGROUP_EGRESS) \
EM(SKB_DROP_REASON_IPV6DISABLED, IPV6DISABLED) \
EM(SKB_DROP_REASON_NEIGH_CREATEFAIL, NEIGH_CREATEFAIL) \
EM(SKB_DROP_REASON_NEIGH_FAILED, NEIGH_FAILED) \
EM(SKB_DROP_REASON_NEIGH_QUEUEFULL, NEIGH_QUEUEFULL) \
EM(SKB_DROP_REASON_NEIGH_DEAD, NEIGH_DEAD) \
EMe(SKB_DROP_REASON_MAX, MAX)
#undef EM

6
net/core/neighbour.c
View File

@ -1171,7 +1171,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
neigh->updated = jiffies;
write_unlock_bh(&neigh->lock);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED);
return 1;
}
} else if (neigh->nud_state & NUD_STALE) {
@ -1193,7 +1193,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
if (!buff)
break;
neigh->arp_queue_len_bytes -= buff->truesize;
kfree_skb(buff);
kfree_skb_reason(buff, SKB_DROP_REASON_NEIGH_QUEUEFULL);
NEIGH_CACHE_STAT_INC(neigh->tbl, unres_discards);
}
skb_dst_force(skb);
@ -1215,7 +1215,7 @@ out_dead:
if (neigh->nud_state & NUD_STALE)
goto out_unlock_bh;
write_unlock_bh(&neigh->lock);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_DEAD);
trace_neigh_event_send_dead(neigh, 1);
return 1;
}

2
net/ipv4/arp.c
View File

@ -293,7 +293,7 @@ static int arp_constructor(struct neighbour *neigh)
static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
{
dst_link_failure(skb);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_FAILED);
}
/* Create and send an arp packet. */

8
net/ipv4/ip_output.c
View File

@ -233,7 +233,7 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s
net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
__func__);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
return -EINVAL;
}
@ -317,7 +317,7 @@ static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *sk
case NET_XMIT_CN:
return __ip_finish_output(net, sk, skb) ? : ret;
default:
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
return ret;
}
}
@ -337,7 +337,7 @@ static int ip_mc_finish_output(struct net *net, struct sock *sk,
case NET_XMIT_SUCCESS:
break;
default:
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
return ret;
}
@ -536,7 +536,7 @@ packet_routed:
no_route:
rcu_read_unlock();
IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_IP_OUTNOROUTES);
return -EHOSTUNREACH;
}
EXPORT_SYMBOL(__ip_queue_xmit);

6
net/ipv6/ip6_output.c
View File

@ -130,7 +130,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
rcu_read_unlock_bh();
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
return -EINVAL;
}
@ -202,7 +202,7 @@ static int ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff *s
case NET_XMIT_CN:
return __ip6_finish_output(net, sk, skb) ? : ret;
default:
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
return ret;
}
}
@ -217,7 +217,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
if (unlikely(idev->cnf.disable_ipv6)) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
return 0;
}