sctp: add pr_debug for tracking asocs not found

This pr_debug may help identify why the system is generating some
Aborts. It's not something a sysadmin would be expected to use.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/input.c

@@ -1229,13 +1229,26 @@ static struct sctp_association *__sctp_rcv_lookup(struct net *net,
 	struct sctp_association *asoc;
 
 	asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
+	if (asoc)
+		goto out;
 
 	/* Further lookup for INIT/INIT-ACK packets.
 	 * SCTP Implementors Guide, 2.18 Handling of address
 	 * parameters within the INIT or INIT-ACK.
 	 */
-	if (!asoc)
-		asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
+	asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp);
+	if (asoc)
+		goto out;
 
+	if (paddr->sa.sa_family == AF_INET)
+		pr_debug("sctp: asoc not found for src:%pI4:%d dst:%pI4:%d\n",
+			 &laddr->v4.sin_addr, ntohs(laddr->v4.sin_port),
+			 &paddr->v4.sin_addr, ntohs(paddr->v4.sin_port));
+	else
+		pr_debug("sctp: asoc not found for src:%pI6:%d dst:%pI6:%d\n",
+			 &laddr->v6.sin6_addr, ntohs(laddr->v6.sin6_port),
+			 &paddr->v6.sin6_addr, ntohs(paddr->v6.sin6_port));
+
+out:
 	return asoc;
 }