netfilter: nf_nat_snmp_basic: use nf_ct_helper_log

Use nf_ct_helper_log to write log message.
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/nf_nat_snmp_basic.c

@@ -1109,7 +1109,7 @@ static int snmp_translate(struct nf_conn *ct, int dir, struct sk_buff *skb)
 
 	if (!snmp_parse_mangle((unsigned char *)udph + sizeof(struct udphdr),
 			       paylen, &map, &udph->check)) {
-		net_warn_ratelimited("bsalg: parser failed\n");
+		nf_ct_helper_log(skb, ct, "parser failed\n");
 		return NF_DROP;
 	}
 	return NF_ACCEPT;
@@ -1143,13 +1143,14 @@ static int help(struct sk_buff *skb, unsigned int protoff,
 	 * can mess around with the payload.
 	 */
 	if (ntohs(udph->len) != skb->len - (iph->ihl << 2)) {
-		net_warn_ratelimited("SNMP: dropping malformed packet src=%pI4 dst=%pI4\n",
-				     &iph->saddr, &iph->daddr);
+		nf_ct_helper_log(skb, ct, "dropping malformed packet\n");
 		return NF_DROP;
 	}
 
-	if (!skb_make_writable(skb, skb->len))
+	if (!skb_make_writable(skb, skb->len)) {
+		nf_ct_helper_log(skb, ct, "cannot mangle packet");
 		return NF_DROP;
+	}
 
 	spin_lock_bh(&snmp_lock);
 	ret = snmp_translate(ct, dir, skb);