net: udp: introduce UDP_MIB_MEMERRORS for udp_mem

When udp_memory_allocated is at the limit, __udp_enqueue_schedule_skb will return a -ENOBUFS, and skb will be dropped in __udp_queue_rcv_skb without any counters being done. It's hard to find out what happened once this happen. So we introduce a UDP_MIB_MEMERRORS to do this job. Well, this change looks friendly to the existing users, such as netstat: $ netstat -u -s Udp: 0 packets received 639 packets to unknown port received. 158689 packet receive errors 180022 packets sent RcvbufErrors: 20930 MemErrors: 137759 UdpLite: IpExt: InOctets: 257426235 OutOctets: 257460598 InNoECTPkts: 181177 v2: - Fix some alignment problems Signed-off-by: Menglong Dong <dong.menglong@zte.com.cn> Link: https://lore.kernel.org/r/1604627354-43207-1-git-send-email-dong.menglong@zte.com.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org>
torvalds · Nov 9, 2020 · a3ce2b1 · a3ce2b1
1 parent bff6f1d
commit a3ce2b1
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diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
@@ -159,6 +159,7 @@ enum
 	UDP_MIB_SNDBUFERRORS,			/* SndbufErrors */
 	UDP_MIB_CSUMERRORS,			/* InCsumErrors */
 	UDP_MIB_IGNOREDMULTI,			/* IgnoredMulti */
+	UDP_MIB_MEMERRORS,			/* MemErrors */
 	__UDP_MIB_MAX
 };
 

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
@@ -167,6 +167,7 @@ static const struct snmp_mib snmp4_udp_list[] = {
 	SNMP_MIB_ITEM("SndbufErrors", UDP_MIB_SNDBUFERRORS),
 	SNMP_MIB_ITEM("InCsumErrors", UDP_MIB_CSUMERRORS),
 	SNMP_MIB_ITEM("IgnoredMulti", UDP_MIB_IGNOREDMULTI),
+	SNMP_MIB_ITEM("MemErrors", UDP_MIB_MEMERRORS),
 	SNMP_MIB_SENTINEL
 };
 

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
@@ -2038,6 +2038,9 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		if (rc == -ENOMEM)
 			UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
 					is_udplite);
+		else
+			UDP_INC_STATS(sock_net(sk), UDP_MIB_MEMERRORS,
+				      is_udplite);
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 		kfree_skb(skb);
 		trace_udp_fail_queue_rcv_skb(rc, sk);

diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
@@ -126,6 +126,7 @@ static const struct snmp_mib snmp6_udp6_list[] = {
 	SNMP_MIB_ITEM("Udp6SndbufErrors", UDP_MIB_SNDBUFERRORS),
 	SNMP_MIB_ITEM("Udp6InCsumErrors", UDP_MIB_CSUMERRORS),
 	SNMP_MIB_ITEM("Udp6IgnoredMulti", UDP_MIB_IGNOREDMULTI),
+	SNMP_MIB_ITEM("Udp6MemErrors", UDP_MIB_MEMERRORS),
 	SNMP_MIB_SENTINEL
 };
 
@@ -137,6 +138,7 @@ static const struct snmp_mib snmp6_udplite6_list[] = {
 	SNMP_MIB_ITEM("UdpLite6RcvbufErrors", UDP_MIB_RCVBUFERRORS),
 	SNMP_MIB_ITEM("UdpLite6SndbufErrors", UDP_MIB_SNDBUFERRORS),
 	SNMP_MIB_ITEM("UdpLite6InCsumErrors", UDP_MIB_CSUMERRORS),
+	SNMP_MIB_ITEM("UdpLite6MemErrors", UDP_MIB_MEMERRORS),
 	SNMP_MIB_SENTINEL
 };
 

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
@@ -637,6 +637,9 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		if (rc == -ENOMEM)
 			UDP6_INC_STATS(sock_net(sk),
 					 UDP_MIB_RCVBUFERRORS, is_udplite);
+		else
+			UDP6_INC_STATS(sock_net(sk),
+				       UDP_MIB_MEMERRORS, is_udplite);
 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 		kfree_skb(skb);
 		return -1;