[PATCH 5.15 076/201] net: skb: use kfree_skb_reason() in __udp4_lib_rcv()

Greg Kroah-Hartman
2022-07-27T17:12:57Z

From: Menglong Dong <imagedong@tencent.com>

[ Upstream commit 1c7fab70df085d866a3765955f397ca2b4025b15 ]

Replace kfree_skb() with kfree_skb_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>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 5305af6cc86f..66aac2006868 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -316,6 +316,7 @@ 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 faa7d068a7bc..3e042ca2cedb 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, MAX)

#undef EM
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 835b9d6e4e68..4ad4daa16cce 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2411,6 +2411,9 @@ 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.
@@ -2466,6 +2469,7 @@ 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);

@@ -2473,10 +2477,11 @@ 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_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),
@@ -2489,6 +2494,7 @@ 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),
@@ -2496,7 +2502,7 @@ 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_reason(skb, drop_reason);
return 0;
}

--
2.35.1