From:   menglong8.dong@gmail.com
To:     rostedt@goodmis.org, dsahern@kernel.org
Cc:     mingo@redhat.com, davem@davemloft.net, kuba@kernel.org,
        nhorman@tuxdriver.com, edumazet@google.com,
        yoshfuji@linux-ipv6.org, jonathan.lemon@gmail.com, alobakin@pm.me,
        keescook@chromium.org, pabeni@redhat.com, talalahmad@google.com,
        haokexin@gmail.com, imagedong@tencent.com, atenart@kernel.org,
        bigeasy@linutronix.de, weiwan@google.com, arnd@arndb.de,
        vvs@virtuozzo.com, cong.wang@bytedance.com,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        mengensun@tencent.com, mungerjiang@tencent.com
Subject: [PATCH net-next 3/3] net: skb: use kfree_skb_with_reason() in __udp4_lib_rcv()
Date:   Thu, 30 Dec 2021 17:32:40 +0800
Message-Id: <20211230093240.1125937-4-imagedong@tencent.com>
In-Reply-To: <20211230093240.1125937-1-imagedong@tencent.com>
References: <20211230093240.1125937-1-imagedong@tencent.com>
MIME-Version: 1.0
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From: Menglong Dong <imagedong@tencent.com>

Replace kfree_skb() with kfree_skb_with_reason() in __udp4_lib_rcv.
New drop reason 'SKB_DROP_REASON_UDP_CSUM' is added for udp csum
error.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h     |  1 +
 include/trace/events/skb.h |  1 +
 net/ipv4/udp.c             | 10 ++++++++--
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 43cb3b75b5af..f0c6949fd19c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -317,6 +317,7 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_PKT_TOO_SMALL,
 	SKB_DROP_REASON_TCP_CSUM,
 	SKB_DROP_REASON_TCP_FILTER,
+	SKB_DROP_REASON_UDP_CSUM,
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index c6f4ecf6781e..f616547dddc6 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -15,6 +15,7 @@
 	EM(SKB_DROP_REASON_PKT_TOO_SMALL, PKT_TOO_SMALL)	\
 	EM(SKB_DROP_REASON_TCP_CSUM, TCP_CSUM)			\
 	EM(SKB_DROP_REASON_TCP_FILTER, TCP_FILTER)		\
+	EM(SKB_DROP_REASON_UDP_CSUM, UDP_CSUM)			\
 	EMe(SKB_DROP_REASON_MAX, HAHA_MAX)
 
 #undef EM
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index f376c777e8fc..463a5adcaacf 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2410,6 +2410,9 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	__be32 saddr, daddr;
 	struct net *net = dev_net(skb->dev);
 	bool refcounted;
+	int drop_reason;
+
+	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 
 	/*
 	 *  Validate the packet.
@@ -2465,6 +2468,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	if (udp_lib_checksum_complete(skb))
 		goto csum_error;
 
+	drop_reason = SKB_DROP_REASON_NO_SOCKET;
 	__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 
@@ -2472,10 +2476,11 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	 * Hmm.  We got an UDP packet to a port to which we
 	 * don't wanna listen.  Ignore it.
 	 */
-	kfree_skb(skb);
+	kfree_skb_with_reason(skb, drop_reason);
 	return 0;
 
 short_packet:
+	drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
 	net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
 			    &saddr, ntohs(uh->source),
@@ -2488,6 +2493,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	 * RFC1122: OK.  Discards the bad packet silently (as far as
 	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
 	 */
+	drop_reason = SKB_DROP_REASON_UDP_CSUM;
 	net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
 			    &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
@@ -2495,7 +2501,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
 drop:
 	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
-	kfree_skb(skb);
+	kfree_skb_with_reason(skb, drop_reason);
 	return 0;
 }
 
-- 
2.30.2