net: sock: add trace for socket errors

This patch will add tracers to trace inet socket errors only. A user
space monitor application can track connection errors indepedent from
socket lifetime and do additional handling. For example a cluster
manager can fence a node if errors occurs in a specific heuristic.

Signed-off-by: Alexander Aring <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Alexander Aring

include/trace/events/sock.h

@@ -201,6 +201,66 @@ TRACE_EVENT(inet_sock_set_state,
 			show_tcp_state_name(__entry->newstate))
 );
 
+TRACE_EVENT(inet_sk_error_report,
+
+	TP_PROTO(const struct sock *sk),
+
+	TP_ARGS(sk),
+
+	TP_STRUCT__entry(
+		__field(int, error)
+		__field(__u16, sport)
+		__field(__u16, dport)
+		__field(__u16, family)
+		__field(__u16, protocol)
+		__array(__u8, saddr, 4)
+		__array(__u8, daddr, 4)
+		__array(__u8, saddr_v6, 16)
+		__array(__u8, daddr_v6, 16)
+	),
+
+	TP_fast_assign(
+		struct inet_sock *inet = inet_sk(sk);
+		struct in6_addr *pin6;
+		__be32 *p32;
+
+		__entry->error = sk->sk_err;
+		__entry->family = sk->sk_family;
+		__entry->protocol = sk->sk_protocol;
+		__entry->sport = ntohs(inet->inet_sport);
+		__entry->dport = ntohs(inet->inet_dport);
+
+		p32 = (__be32 *) __entry->saddr;
+		*p32 = inet->inet_saddr;
+
+		p32 = (__be32 *) __entry->daddr;
+		*p32 =  inet->inet_daddr;
+
+#if IS_ENABLED(CONFIG_IPV6)
+		if (sk->sk_family == AF_INET6) {
+			pin6 = (struct in6_addr *)__entry->saddr_v6;
+			*pin6 = sk->sk_v6_rcv_saddr;
+			pin6 = (struct in6_addr *)__entry->daddr_v6;
+			*pin6 = sk->sk_v6_daddr;
+		} else
+#endif
+		{
+			pin6 = (struct in6_addr *)__entry->saddr_v6;
+			ipv6_addr_set_v4mapped(inet->inet_saddr, pin6);
+			pin6 = (struct in6_addr *)__entry->daddr_v6;
+			ipv6_addr_set_v4mapped(inet->inet_daddr, pin6);
+		}
+	),
+
+	TP_printk("family=%s protocol=%s sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c error=%d",
+		  show_family_name(__entry->family),
+		  show_inet_protocol_name(__entry->protocol),
+		  __entry->sport, __entry->dport,
+		  __entry->saddr, __entry->daddr,
+		  __entry->saddr_v6, __entry->daddr_v6,
+		  __entry->error)
+);
+
 #endif /* _TRACE_SOCK_H */
 
 /* This part must be outside protection */

net/core/sock.c

@@ -334,6 +334,16 @@ EXPORT_SYMBOL(__sk_backlog_rcv);
 void sk_error_report(struct sock *sk)
 {
 	sk->sk_error_report(sk);
+
+	switch (sk->sk_family) {
+	case AF_INET:
+		fallthrough;
+	case AF_INET6:
+		trace_inet_sk_error_report(sk);
+		break;
+	default:
+		break;
+	}
 }
 EXPORT_SYMBOL(sk_error_report);