net: snmp: add snmp tracepoint support for udp

Add snmp tracepoint support for udp. Here is the new tracepoint:
/sys/kernel/debug/tracing/events/snmp/snmp_udp/

Signed-off-by: Menglong Dong <imagedong@tencent.com>

include/net/udp.h

@@ -28,6 +28,7 @@
 #include <linux/seq_file.h>
 #include <linux/poll.h>
 #include <linux/indirect_call_wrapper.h>
+#include <trace/events/snmp.h>
 
 /**
  *	struct udp_skb_cb  -  UDP(-Lite) private variables
@@ -408,12 +409,24 @@ static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
 /*
  * 	SNMP statistics for UDP and UDP-Lite
  */
-#define UDP_INC_STATS(net, field, is_udplite)		      do { \
-	if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field);       \
-	else		SNMP_INC_STATS((net)->mib.udp_statistics, field);  }  while(0)
-#define __UDP_INC_STATS(net, field, is_udplite) 	      do { \
-	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field);         \
-	else		__SNMP_INC_STATS((net)->mib.udp_statistics, field);    }  while(0)
+#define UDP_INC_STATS(net, field, is_udplite)			do {	\
+	if (is_udplite) {						\
+		SNMP_INC_STATS((net)->mib.udplite_statistics, field);	\
+		TRACE_SNMP(skb, udp, field, 1);				\
+	} else {							\
+		SNMP_INC_STATS((net)->mib.udp_statistics, field);	\
+		TRACE_SNMP(skb, udplite, field, 1);			\
+	}								\
+} while (0)
+#define __UDP_INC_STATS(net, skb, field, is_udplite)		do {	\
+	if (is_udplite) {						\
+		__SNMP_INC_STATS((net)->mib.udplite_statistics, field);	\
+		TRACE_SNMP(skb, udp, field, 1);				\
+	} else {							\
+		__SNMP_INC_STATS((net)->mib.udp_statistics, field);	\
+		TRACE_SNMP(skb, udplite, field, 1);			\
+	}								\
+}  while (0)
 
 #define __UDP6_INC_STATS(net, field, is_udplite)	    do { \
 	if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\

include/trace/events/snmp.h

@@ -37,6 +37,11 @@ DEFINE_EVENT(snmp_template, snmp_##proto,			\
 	TP_ARGS(skb, field, val)				\
 )
 
+
+
+DEFINE_SNMP_EVENT(udp);
+DEFINE_SNMP_EVENT(udplite);
+
 #define TRACE_SNMP(skb, proto, field, val) \
 	trace_snmp_##proto(skb, field, val)
 

net/core/net-traces.c

@@ -62,3 +62,5 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(napi_poll);
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(tcp_send_reset);
 EXPORT_TRACEPOINT_SYMBOL_GPL(tcp_bad_csum);
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(snmp_udp);

net/ipv4/udp.c

@@ -1649,9 +1649,11 @@ static struct sk_buff *__first_packet_length(struct sock *sk,
 
 	while ((skb = skb_peek(rcvq)) != NULL) {
 		if (udp_lib_checksum_complete(skb)) {
-			__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
+			__UDP_INC_STATS(sock_net(sk), skb,
+					UDP_MIB_CSUMERRORS,
 					IS_UDPLITE(sk));
-			__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
+			__UDP_INC_STATS(sock_net(sk), skb,
+					UDP_MIB_INERRORS,
 					IS_UDPLITE(sk));
 			atomic_inc(&sk->sk_drops);
 			__skb_unlink(skb, rcvq);
@@ -2144,7 +2146,7 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 
 			ret = encap_rcv(sk, skb);
 			if (ret <= 0) {
-				__UDP_INC_STATS(sock_net(sk),
+				__UDP_INC_STATS(sock_net(sk), skb,
 						UDP_MIB_INDATAGRAMS,
 						is_udplite);
 				return -ret;
@@ -2202,9 +2204,10 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
 	return __udp_queue_rcv_skb(sk, skb);
 
 csum_error:
-	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
+	__UDP_INC_STATS(sock_net(sk), skb, UDP_MIB_CSUMERRORS,
+			is_udplite);
 drop:
-	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+	__UDP_INC_STATS(sock_net(sk), skb, UDP_MIB_INERRORS, is_udplite);
 	atomic_inc(&sk->sk_drops);
 	kfree_skb(skb);
 	return -1;
@@ -2291,9 +2294,9 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 
 		if (unlikely(!nskb)) {
 			atomic_inc(&sk->sk_drops);
-			__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
+			__UDP_INC_STATS(net, skb, UDP_MIB_RCVBUFERRORS,
 					IS_UDPLITE(sk));
-			__UDP_INC_STATS(net, UDP_MIB_INERRORS,
+			__UDP_INC_STATS(net, skb, UDP_MIB_INERRORS,
 					IS_UDPLITE(sk));
 			continue;
 		}
@@ -2312,7 +2315,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 			consume_skb(skb);
 	} else {
 		kfree_skb(skb);
-		__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
+		__UDP_INC_STATS(net, skb, UDP_MIB_IGNOREDMULTI,
 				proto == IPPROTO_UDPLITE);
 	}
 	return 0;
@@ -2455,7 +2458,8 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	if (udp_lib_checksum_complete(skb))
 		goto csum_error;
 
-	__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
+	__UDP_INC_STATS(net, skb, UDP_MIB_NOPORTS,
+			proto == IPPROTO_UDPLITE);
 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 
 	/*
@@ -2482,9 +2486,11 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
 			    &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
 			    ulen);
-	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
+	__UDP_INC_STATS(net, skb, UDP_MIB_CSUMERRORS,
+			proto == IPPROTO_UDPLITE);
 drop:
-	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
+	__UDP_INC_STATS(net, skb, UDP_MIB_INERRORS,
+			proto == IPPROTO_UDPLITE);
 	kfree_skb(skb);
 	return 0;
 }