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Subject: [PATCH net-next 5/6] net: udp: use kfree_skb_reason() in udp_queue_rcv_one_skb()
Date:   Mon, 24 Jan 2022 21:15:37 +0800
Message-Id: <20220124131538.1453657-6-imagedong@tencent.com>
In-Reply-To: <20220124131538.1453657-1-imagedong@tencent.com>
References: <20220124131538.1453657-1-imagedong@tencent.com>
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From: Menglong Dong <imagedong@tencent.com>

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

SKB_DROP_REASON_UDP_FILTER

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h     |  1 +
 include/trace/events/skb.h |  1 +
 net/ipv4/udp.c             | 12 +++++++++---
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 603f77ef2170..dd64a4f2ff1d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -330,6 +330,7 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST,
 	SKB_DROP_REASON_XFRM_POLICY,
 	SKB_DROP_REASON_IP_NOPROTO,
+	SKB_DROP_REASON_UDP_FILTER,
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index e8369b8e8430..6db61ce4d6f5 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -27,6 +27,7 @@
 	   UNICAST_IN_L2_MULTICAST)				\
 	EM(SKB_DROP_REASON_XFRM_POLICY, XFRM_POLICY)		\
 	EM(SKB_DROP_REASON_IP_NOPROTO, IP_NOPROTO)		\
+	EM(SKB_DROP_REASON_UDP_FILTER, UDP_FILTER)		\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 464590ea922e..57681e98e6bf 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2120,14 +2120,17 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
  */
 static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 {
+	int drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	struct udp_sock *up = udp_sk(sk);
 	int is_udplite = IS_UDPLITE(sk);
 
 	/*
 	 *	Charge it to the socket, dropping if the queue is full.
 	 */
-	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
+	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
 		goto drop;
+	}
 	nf_reset_ct(skb);
 
 	if (static_branch_unlikely(&udp_encap_needed_key) && up->encap_type) {
@@ -2204,8 +2207,10 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 	    udp_lib_checksum_complete(skb))
 			goto csum_error;
 
-	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
+	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) {
+		drop_reason = SKB_DROP_REASON_UDP_FILTER;
 		goto drop;
+	}
 
 	udp_csum_pull_header(skb);
 
@@ -2213,11 +2218,12 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 	return __udp_queue_rcv_skb(sk, skb);
 
 csum_error:
+	drop_reason = SKB_DROP_REASON_UDP_CSUM;
 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
 drop:
 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 	atomic_inc(&sk->sk_drops);
-	kfree_skb(skb);
+	kfree_skb_reason(skb, drop_reason);
 	return -1;
 }
 
-- 
2.34.1