sit: generate icmpv6 error when receiving icmpv4 error

	dev_put(dev);

}

/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH

 * if sufficient data bytes are available

 */

static int ipip6_err_gen_icmpv6_unreach(struct sk_buff *skb)

{

	const struct iphdr *iph = (const struct iphdr *) skb->data;

	struct rt6_info *rt;

	struct sk_buff *skb2;

	if (!pskb_may_pull(skb, iph->ihl * 4 + sizeof(struct ipv6hdr) + 8))

		return 1;

	skb2 = skb_clone(skb, GFP_ATOMIC);

	if (!skb2)

		return 1;

	skb_dst_drop(skb2);

	skb_pull(skb2, iph->ihl * 4);

	skb_reset_network_header(skb2);

	rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);

	if (rt && rt->dst.dev)

		skb2->dev = rt->dst.dev;

	icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);

	if (rt)

		ip6_rt_put(rt);

	kfree_skb(skb2);

	return 0;

}

static int ipip6_err(struct sk_buff *skb, u32 info)

{

/* All the routers (except for Linux) return only

   8 bytes of packet payload. It means, that precise relaying of

   ICMP in the real Internet is absolutely infeasible.

 */

	const struct iphdr *iph = (const struct iphdr *)skb->data;

	const int type = icmp_hdr(skb)->type;

	const int code = icmp_hdr(skb)->code;

	case ICMP_DEST_UNREACH:

		switch (code) {

		case ICMP_SR_FAILED:

		case ICMP_PORT_UNREACH:

			/* Impossible event. */

			return 0;

		default:

		goto out;

	err = 0;

	if (!ipip6_err_gen_icmpv6_unreach(skb))

		goto out;

	if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)

		goto out;