/*
   * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
   * Copyright (C) 2002 USAGI/WIDE Project
   * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>

   *

   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */

  #include <linux/if_ether.h>

  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/skbuff.h>

  #include <linux/icmpv6.h>

  #include <linux/netfilter_ipv6.h>

  #include <net/dst.h>

  #include <net/ipv6.h>

  #include <net/ip6_route.h>

  #include <net/xfrm.h>

  int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
  			  u8 **prevhdr)
  {
  	return ip6_find_1stfragopt(skb, prevhdr);
  }

  EXPORT_SYMBOL(xfrm6_find_1stfragopt);

  static int xfrm6_local_dontfrag(struct sk_buff *skb)
  {
  	int proto;
  	struct sock *sk = skb->sk;
  
  	if (sk) {
  		proto = sk->sk_protocol;
  
  		if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
  			return inet6_sk(sk)->dontfrag;
  	}
  
  	return 0;
  }
  
  static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
  {
  	struct flowi6 fl6;
  	struct sock *sk = skb->sk;
  
  	fl6.flowi6_oif = sk->sk_bound_dev_if;

  	fl6.daddr = ipv6_hdr(skb)->daddr;

  
  	ipv6_local_rxpmtu(sk, &fl6, mtu);
  }
  
  static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
  {
  	struct flowi6 fl6;
  	struct sock *sk = skb->sk;
  
  	fl6.fl6_dport = inet_sk(sk)->inet_dport;

  	fl6.daddr = ipv6_hdr(skb)->daddr;

  
  	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
  }

  static int xfrm6_tunnel_check_size(struct sk_buff *skb)
  {
  	int mtu, ret = 0;

  	struct dst_entry *dst = skb_dst(skb);

  
  	mtu = dst_mtu(dst);
  	if (mtu < IPV6_MIN_MTU)
  		mtu = IPV6_MIN_MTU;

  	if (!skb->local_df && skb->len > mtu) {

  		skb->dev = dst->dev;

  
  		if (xfrm6_local_dontfrag(skb))
  			xfrm6_local_rxpmtu(skb, mtu);
  		else if (skb->sk)
  			xfrm6_local_error(skb, mtu);
  		else
  			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

  		ret = -EMSGSIZE;
  	}
  
  	return ret;
  }

  int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
  {
  	int err;
  
  	err = xfrm6_tunnel_check_size(skb);
  	if (err)
  		return err;

  	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;

  	return xfrm6_extract_header(skb);
  }
  
  int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
  {
  	int err;

  	err = xfrm_inner_extract_output(x, skb);

  	if (err)
  		return err;
  
  	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));

  #ifdef CONFIG_NETFILTER
  	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
  #endif

  
  	skb->protocol = htons(ETH_P_IPV6);

  	skb->local_df = 1;

  
  	return x->outer_mode->output2(x, skb);
  }
  EXPORT_SYMBOL(xfrm6_prepare_output);

  int xfrm6_output_finish(struct sk_buff *skb)

  {

  #ifdef CONFIG_NETFILTER
  	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
  #endif

  	skb->protocol = htons(ETH_P_IPV6);

  	return xfrm_output(skb);

  }

  static int __xfrm6_output(struct sk_buff *skb)
  {
  	struct dst_entry *dst = skb_dst(skb);
  	struct xfrm_state *x = dst->xfrm;

  	int mtu = ip6_skb_dst_mtu(skb);
  
  	if (skb->len > mtu && xfrm6_local_dontfrag(skb)) {
  		xfrm6_local_rxpmtu(skb, mtu);
  		return -EMSGSIZE;
  	} else if (!skb->local_df && skb->len > mtu && skb->sk) {
  		xfrm6_local_error(skb, mtu);
  		return -EMSGSIZE;
  	}

  
  	if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&

  	    ((skb->len > mtu && !skb_is_gso(skb)) ||

  		dst_allfrag(skb_dst(skb)))) {

  			return ip6_fragment(skb, x->outer_mode->afinfo->output_finish);

  	}

  	return x->outer_mode->afinfo->output_finish(skb);

  }

  int xfrm6_output(struct sk_buff *skb)
  {

  	return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,

  		       skb_dst(skb)->dev, __xfrm6_output);

  }