From 5e187189ec324f78035d33a4bc123a9c4ca6f3e3 Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Sat, 26 Feb 2022 12:18:29 +0800 Subject: [PATCH 1/3] net: ip: add skb drop reasons for ip egress path Replace kfree_skb() which is used in the packet egress path of IP layer with kfree_skb_reason(). Functions that are involved include: __ip_queue_xmit() ip_finish_output() ip_mc_finish_output() ip6_output() ip6_finish_output() ip6_finish_output2() Following new drop reasons are introduced: SKB_DROP_REASON_IP_OUTNOROUTES SKB_DROP_REASON_BPF_CGROUP_EGRESS SKB_DROP_REASON_IPV6DISABLED SKB_DROP_REASON_NEIGH_CREATEFAIL Reviewed-by: Mengen Sun Reviewed-by: Hao Peng Signed-off-by: Menglong Dong Reviewed-by: David Ahern Signed-off-by: David S. Miller --- include/linux/skbuff.h | 9 +++++++++ include/trace/events/skb.h | 5 +++++ net/ipv4/ip_output.c | 8 ++++---- net/ipv6/ip6_output.c | 6 +++--- 4 files changed, 21 insertions(+), 7 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 31be380789180..62b4bed1b7bcf 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -380,6 +380,15 @@ 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_MAX, }; diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h index 2ab7193313aa4..97f8097651da1 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -37,6 +37,11 @@ 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) \ EMe(SKB_DROP_REASON_MAX, MAX) #undef EM diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 2941de5da871a..6df3545c891de 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -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 @@ int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, 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); diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index c5c10f7980253..c5edc86b18bd5 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -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; } From a5736edda10ca2ba075606baad1dda3f2426766d Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Sat, 26 Feb 2022 12:18:30 +0800 Subject: [PATCH 2/3] net: neigh: use kfree_skb_reason() for __neigh_event_send() Replace kfree_skb() used in __neigh_event_send() with kfree_skb_reason(). Following drop reasons are added: SKB_DROP_REASON_NEIGH_FAILED SKB_DROP_REASON_NEIGH_QUEUEFULL SKB_DROP_REASON_NEIGH_DEAD The first two reasons above should be the hot path that skb drops in neighbour subsystem. Reviewed-by: Mengen Sun Reviewed-by: Hao Peng Signed-off-by: Menglong Dong Reviewed-by: David Ahern Signed-off-by: David S. Miller --- include/linux/skbuff.h | 5 +++++ include/trace/events/skb.h | 3 +++ net/core/neighbour.c | 6 +++--- 3 files changed, 11 insertions(+), 3 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 62b4bed1b7bcf..d67941f78b92a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -389,6 +389,11 @@ enum skb_drop_reason { 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, }; diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h index 97f8097651da1..1977f301260da 100644 --- a/include/trace/events/skb.h +++ b/include/trace/events/skb.h @@ -42,6 +42,9 @@ 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 diff --git a/net/core/neighbour.c b/net/core/neighbour.c index ec0bf737b076a..f64ebd050f6c4 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -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 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb, 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; } From 56d4b4e48ace91ee4e41991438e0e11688750617 Mon Sep 17 00:00:00 2001 From: Menglong Dong Date: Sat, 26 Feb 2022 12:18:31 +0800 Subject: [PATCH 3/3] net: neigh: add skb drop reasons to arp_error_report() When neighbour become invalid or destroyed, neigh_invalidate() will be called. neigh->ops->error_report() will be called if the neighbour's state is NUD_FAILED, and seems here is the only use of error_report(). So we can tell that the reason of skb drops in arp_error_report() is SKB_DROP_REASON_NEIGH_FAILED. Replace kfree_skb() used in arp_error_report() with kfree_skb_reason(). Reviewed-by: Mengen Sun Reviewed-by: Hao Peng Signed-off-by: Menglong Dong Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/arp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index dc28f0588e540..2d0c05ca9c6f1 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -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. */