sunvnet: use icmp_ndo_send helper

BugLink: https://bugs.launchpad.net/bugs/1918974

commit 67c9a7e upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

Author: zx2c4

drivers/net/ethernet/sun/sunvnet_common.c

@@ -1353,27 +1353,12 @@ 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;
 	}