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 <mengensun@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Menglong Dong <imagedong@tencent.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
mariux64 · Feb 26, 2022 · 5e18718 · 5e18718
1 parent 0cc70c6
commit 5e18718
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Showing 4 changed files with 21 additions and 7 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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;
 	}