net: udp: add IP/port data to the tracepoint udp/udp_fail_queue_rcv_skb

The udp_fail_queue_rcv_skb() tracepoint lacks any details on the source
and destination IP/port whereas this information can be critical in case
of UDP/syslog.
Signed-off-by: Balazs Scheidler <balazs.scheidler@axoflow.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://lore.kernel.org/r/0c8b3e33dbf679e190be6f4c6736603a76988a20.1711475011.git.balazs.scheidler@axoflow.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/trace/events/udp.h

@@ -7,24 +7,43 @@
 
 #include <linux/udp.h>
 #include <linux/tracepoint.h>
+#include <trace/events/net_probe_common.h>
 
 TRACE_EVENT(udp_fail_queue_rcv_skb,
 
-	TP_PROTO(int rc, struct sock *sk),
+	TP_PROTO(int rc, struct sock *sk, struct sk_buff *skb),
 
-	TP_ARGS(rc, sk),
+	TP_ARGS(rc, sk, skb),
 
 	TP_STRUCT__entry(
 		__field(int, rc)
-		__field(__u16, lport)
+
+		__field(__u16, sport)
+		__field(__u16, dport)
+		__field(__u16, family)
+		__array(__u8, saddr, sizeof(struct sockaddr_in6))
+		__array(__u8, daddr, sizeof(struct sockaddr_in6))
 	),
 
 	TP_fast_assign(
+		const struct udphdr *uh = (const struct udphdr *)udp_hdr(skb);
+
 		__entry->rc = rc;
-		__entry->lport = inet_sk(sk)->inet_num;
+
+		/* for filtering use */
+		__entry->sport = ntohs(uh->source);
+		__entry->dport = ntohs(uh->dest);
+		__entry->family = sk->sk_family;
+
+		memset(__entry->saddr, 0, sizeof(struct sockaddr_in6));
+		memset(__entry->daddr, 0, sizeof(struct sockaddr_in6));
+
+		TP_STORE_ADDR_PORTS_SKB(__entry, skb, uh);
 	),
 
-	TP_printk("rc=%d port=%hu", __entry->rc, __entry->lport)
+	TP_printk("rc=%d family=%s src=%pISpc dest=%pISpc", __entry->rc,
+		  show_family_name(__entry->family),
+		  __entry->saddr, __entry->daddr)
 );
 
 #endif /* _TRACE_UDP_H */

net/ipv4/udp.c

@@ -2049,8 +2049,8 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 			drop_reason = SKB_DROP_REASON_PROTO_MEM;
 		}
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+		trace_udp_fail_queue_rcv_skb(rc, sk, skb);
 		kfree_skb_reason(skb, drop_reason);
-		trace_udp_fail_queue_rcv_skb(rc, sk);
 		return -1;
 	}
 

net/ipv6/udp.c

@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/indirect_call_wrapper.h>
+#include <trace/events/udp.h>
 
 #include <net/addrconf.h>
 #include <net/ndisc.h>
@@ -658,8 +659,8 @@ static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 			drop_reason = SKB_DROP_REASON_PROTO_MEM;
 		}
 		UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+		trace_udp_fail_queue_rcv_skb(rc, sk, skb);
 		kfree_skb_reason(skb, drop_reason);
-		trace_udp_fail_queue_rcv_skb(rc, sk);
 		return -1;
 	}