sunvnet: use icmp_ndo_send helper

Because sunvnet is calling icmp from network device context, it should use
the ndo helper so that the rate limiting applies correctly. While we're
at it, doing the additional route lookup before calling icmp_ndo_send is
superfluous, since this is the job of the icmp code in the first place.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sun/sunvnet_common.c

@@ -1350,27 +1350,12 @@ sunvnet_start_xmit_common(struct sk_buff *skb, struct net_device *dev,
 		if (vio_version_after_eq(&port->vio, 1, 3))
 			localmtu -= VLAN_HLEN;
 
-		if (skb->protocol == htons(ETH_P_IP)) {
-			struct flowi4 fl4;
-			struct rtable *rt = NULL;
-
-			memset(&fl4, 0, sizeof(fl4));
-			fl4.flowi4_oif = dev->ifindex;
-			fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
-			fl4.daddr = ip_hdr(skb)->daddr;
-			fl4.saddr = ip_hdr(skb)->saddr;
-
-			rt = ip_route_output_key(dev_net(dev), &fl4);
-			if (!IS_ERR(rt)) {
-				skb_dst_set(skb, &rt->dst);
-				icmp_send(skb, ICMP_DEST_UNREACH,
-					  ICMP_FRAG_NEEDED,
-					  htonl(localmtu));
-			}
-		}
+		if (skb->protocol == htons(ETH_P_IP))
+			icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
+				      htonl(localmtu));
 #if IS_ENABLED(CONFIG_IPV6)
 		else if (skb->protocol == htons(ETH_P_IPV6))
-			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
+			icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, localmtu);
 #endif
 		goto out_dropped;
 	}