/*
   *	IPv6 output functions

   *	Linux INET6 implementation

   *
   *	Authors:

   *	Pedro Roque		<roque@di.fc.ul.pt>

   *
   *	$Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $
   *
   *	Based on linux/net/ipv4/ip_output.c
   *
   *	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.
   *
   *	Changes:
   *	A.N.Kuznetsov	:	airthmetics in fragmentation.
   *				extension headers are implemented.
   *				route changes now work.
   *				ip6_forward does not confuse sniffers.
   *				etc.
   *
   *      H. von Brand    :       Added missing #include <linux/string.h>
   *	Imran Patel	: 	frag id should be in NBO
   *      Kazunori MIYAZAWA @USAGI
   *			:       add ip6_append_data and related functions
   *				for datagram xmit
   */

  #include <linux/errno.h>
  #include <linux/types.h>
  #include <linux/string.h>
  #include <linux/socket.h>
  #include <linux/net.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <linux/in6.h>
  #include <linux/tcp.h>
  #include <linux/route.h>

  #include <linux/module.h>

  
  #include <linux/netfilter.h>
  #include <linux/netfilter_ipv6.h>
  
  #include <net/sock.h>
  #include <net/snmp.h>
  
  #include <net/ipv6.h>
  #include <net/ndisc.h>
  #include <net/protocol.h>
  #include <net/ip6_route.h>
  #include <net/addrconf.h>
  #include <net/rawv6.h>
  #include <net/icmp.h>
  #include <net/xfrm.h>
  #include <net/checksum.h>
  
  static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
  
  static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr)
  {
  	static u32 ipv6_fragmentation_id = 1;
  	static DEFINE_SPINLOCK(ip6_id_lock);
  
  	spin_lock_bh(&ip6_id_lock);
  	fhdr->identification = htonl(ipv6_fragmentation_id);
  	if (++ipv6_fragmentation_id == 0)
  		ipv6_fragmentation_id = 1;
  	spin_unlock_bh(&ip6_id_lock);
  }
  
  static inline int ip6_output_finish(struct sk_buff *skb)
  {

  	struct dst_entry *dst = skb->dst;

  	if (dst->hh)
  		return neigh_hh_output(dst->hh, skb);
  	else if (dst->neighbour)

  		return dst->neighbour->output(skb);

  	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);

  	kfree_skb(skb);
  	return -EINVAL;
  
  }
  
  /* dev_loopback_xmit for use with netfilter. */
  static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
  {

  	skb_reset_mac_header(newskb);

  	__skb_pull(newskb, skb_network_offset(newskb));

  	newskb->pkt_type = PACKET_LOOPBACK;
  	newskb->ip_summed = CHECKSUM_UNNECESSARY;
  	BUG_TRAP(newskb->dst);
  
  	netif_rx(newskb);
  	return 0;
  }
  
  
  static int ip6_output2(struct sk_buff *skb)
  {
  	struct dst_entry *dst = skb->dst;
  	struct net_device *dev = dst->dev;
  
  	skb->protocol = htons(ETH_P_IPV6);
  	skb->dev = dev;

  	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {

  		struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;

  		struct inet6_dev *idev = ip6_dst_idev(skb->dst);

  
  		if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&

  		    ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
  					&ipv6_hdr(skb)->saddr)) {

  			struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
  
  			/* Do not check for IFF_ALLMULTI; multicast routing
  			   is not supported in any case.
  			 */
  			if (newskb)
  				NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL,
  					newskb->dev,
  					ip6_dev_loopback_xmit);

  			if (ipv6_hdr(skb)->hop_limit == 0) {

  				IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS);

  				kfree_skb(skb);
  				return 0;
  			}
  		}

  		IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS);

  	}
  
  	return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish);
  }

  static inline int ip6_skb_dst_mtu(struct sk_buff *skb)
  {
  	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
  
  	return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ?
  	       skb->dst->dev->mtu : dst_mtu(skb->dst);
  }

  int ip6_output(struct sk_buff *skb)
  {

  	if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||

  				dst_allfrag(skb->dst))

  		return ip6_fragment(skb, ip6_output2);
  	else
  		return ip6_output2(skb);
  }

  /*
   *	xmit an sk_buff (used by TCP)
   */
  
  int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
  	     struct ipv6_txoptions *opt, int ipfragok)
  {

  	struct ipv6_pinfo *np = inet6_sk(sk);

  	struct in6_addr *first_hop = &fl->fl6_dst;
  	struct dst_entry *dst = skb->dst;
  	struct ipv6hdr *hdr;
  	u8  proto = fl->proto;
  	int seg_len = skb->len;

  	int hlimit, tclass;

  	u32 mtu;
  
  	if (opt) {
  		int head_room;
  
  		/* First: exthdrs may take lots of space (~8K for now)
  		   MAX_HEADER is not enough.
  		 */
  		head_room = opt->opt_nflen + opt->opt_flen;
  		seg_len += head_room;
  		head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
  
  		if (skb_headroom(skb) < head_room) {
  			struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);

  			if (skb2 == NULL) {
  				IP6_INC_STATS(ip6_dst_idev(skb->dst),
  					      IPSTATS_MIB_OUTDISCARDS);
  				kfree_skb(skb);

  				return -ENOBUFS;
  			}

  			kfree_skb(skb);
  			skb = skb2;

  			if (sk)
  				skb_set_owner_w(skb, sk);
  		}
  		if (opt->opt_flen)
  			ipv6_push_frag_opts(skb, opt, &proto);
  		if (opt->opt_nflen)
  			ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
  	}

  	skb_push(skb, sizeof(struct ipv6hdr));
  	skb_reset_network_header(skb);

  	hdr = ipv6_hdr(skb);

  
  	/*
  	 *	Fill in the IPv6 header
  	 */

  	hlimit = -1;
  	if (np)
  		hlimit = np->hop_limit;
  	if (hlimit < 0)
  		hlimit = dst_metric(dst, RTAX_HOPLIMIT);
  	if (hlimit < 0)
  		hlimit = ipv6_get_hoplimit(dst->dev);

  	tclass = -1;
  	if (np)
  		tclass = np->tclass;
  	if (tclass < 0)
  		tclass = 0;

  	*(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;

  	hdr->payload_len = htons(seg_len);
  	hdr->nexthdr = proto;
  	hdr->hop_limit = hlimit;
  
  	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
  	ipv6_addr_copy(&hdr->daddr, first_hop);

  	skb->priority = sk->sk_priority;

  	mtu = dst_mtu(dst);

  	if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) {

  		IP6_INC_STATS(ip6_dst_idev(skb->dst),
  			      IPSTATS_MIB_OUTREQUESTS);

  		return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
  				dst_output);

  	}
  
  	if (net_ratelimit())
  		printk(KERN_DEBUG "IPv6: sending pkt_too_big to self
  ");
  	skb->dev = dst->dev;
  	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);

  	IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);

  	kfree_skb(skb);
  	return -EMSGSIZE;
  }

  EXPORT_SYMBOL(ip6_xmit);

  /*
   *	To avoid extra problems ND packets are send through this
   *	routine. It's code duplication but I really want to avoid
   *	extra checks since ipv6_build_header is used by TCP (which
   *	is for us performance critical)
   */
  
  int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
  	       struct in6_addr *saddr, struct in6_addr *daddr,
  	       int proto, int len)
  {
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct ipv6hdr *hdr;
  	int totlen;
  
  	skb->protocol = htons(ETH_P_IPV6);
  	skb->dev = dev;
  
  	totlen = len + sizeof(struct ipv6hdr);

  	skb_reset_network_header(skb);
  	skb_put(skb, sizeof(struct ipv6hdr));

  	hdr = ipv6_hdr(skb);

  	*(__be32*)hdr = htonl(0x60000000);

  
  	hdr->payload_len = htons(len);
  	hdr->nexthdr = proto;
  	hdr->hop_limit = np->hop_limit;
  
  	ipv6_addr_copy(&hdr->saddr, saddr);
  	ipv6_addr_copy(&hdr->daddr, daddr);
  
  	return 0;
  }
  
  static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
  {
  	struct ip6_ra_chain *ra;
  	struct sock *last = NULL;
  
  	read_lock(&ip6_ra_lock);
  	for (ra = ip6_ra_chain; ra; ra = ra->next) {
  		struct sock *sk = ra->sk;

  		if (sk && ra->sel == sel &&
  		    (!sk->sk_bound_dev_if ||
  		     sk->sk_bound_dev_if == skb->dev->ifindex)) {

  			if (last) {
  				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
  				if (skb2)
  					rawv6_rcv(last, skb2);
  			}
  			last = sk;
  		}
  	}
  
  	if (last) {
  		rawv6_rcv(last, skb);
  		read_unlock(&ip6_ra_lock);
  		return 1;
  	}
  	read_unlock(&ip6_ra_lock);
  	return 0;
  }

  static int ip6_forward_proxy_check(struct sk_buff *skb)
  {

  	struct ipv6hdr *hdr = ipv6_hdr(skb);

  	u8 nexthdr = hdr->nexthdr;
  	int offset;
  
  	if (ipv6_ext_hdr(nexthdr)) {
  		offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr);
  		if (offset < 0)
  			return 0;
  	} else
  		offset = sizeof(struct ipv6hdr);
  
  	if (nexthdr == IPPROTO_ICMPV6) {
  		struct icmp6hdr *icmp6;

  		if (!pskb_may_pull(skb, (skb_network_header(skb) +
  					 offset + 1 - skb->data)))

  			return 0;

  		icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);

  
  		switch (icmp6->icmp6_type) {
  		case NDISC_ROUTER_SOLICITATION:
  		case NDISC_ROUTER_ADVERTISEMENT:
  		case NDISC_NEIGHBOUR_SOLICITATION:
  		case NDISC_NEIGHBOUR_ADVERTISEMENT:
  		case NDISC_REDIRECT:
  			/* For reaction involving unicast neighbor discovery
  			 * message destined to the proxied address, pass it to
  			 * input function.
  			 */
  			return 1;
  		default:
  			break;
  		}
  	}

  	/*
  	 * The proxying router can't forward traffic sent to a link-local
  	 * address, so signal the sender and discard the packet. This
  	 * behavior is clarified by the MIPv6 specification.
  	 */
  	if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) {
  		dst_link_failure(skb);
  		return -1;
  	}

  	return 0;
  }

  static inline int ip6_forward_finish(struct sk_buff *skb)
  {
  	return dst_output(skb);
  }
  
  int ip6_forward(struct sk_buff *skb)
  {
  	struct dst_entry *dst = skb->dst;

  	struct ipv6hdr *hdr = ipv6_hdr(skb);

  	struct inet6_skb_parm *opt = IP6CB(skb);

  	if (ipv6_devconf.forwarding == 0)
  		goto error;
  
  	if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {

  		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);

  		goto drop;
  	}

  	skb_forward_csum(skb);

  
  	/*
  	 *	We DO NOT make any processing on
  	 *	RA packets, pushing them to user level AS IS
  	 *	without ane WARRANTY that application will be able
  	 *	to interpret them. The reason is that we
  	 *	cannot make anything clever here.
  	 *
  	 *	We are not end-node, so that if packet contains
  	 *	AH/ESP, we cannot make anything.
  	 *	Defragmentation also would be mistake, RA packets
  	 *	cannot be fragmented, because there is no warranty
  	 *	that different fragments will go along one path. --ANK
  	 */
  	if (opt->ra) {

  		u8 *ptr = skb_network_header(skb) + opt->ra;

  		if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
  			return 0;
  	}
  
  	/*
  	 *	check and decrement ttl
  	 */
  	if (hdr->hop_limit <= 1) {
  		/* Force OUTPUT device used as source address */
  		skb->dev = dst->dev;
  		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
  			    0, skb->dev);

  		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);

  
  		kfree_skb(skb);
  		return -ETIMEDOUT;
  	}

  	/* XXX: idev->cnf.proxy_ndp? */
  	if (ipv6_devconf.proxy_ndp &&
  	    pneigh_lookup(&nd_tbl, &hdr->daddr, skb->dev, 0)) {

  		int proxied = ip6_forward_proxy_check(skb);
  		if (proxied > 0)

  			return ip6_input(skb);

  		else if (proxied < 0) {

  			IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);

  			goto drop;
  		}

  	}

  	if (!xfrm6_route_forward(skb)) {

  		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS);

  		goto drop;
  	}
  	dst = skb->dst;
  
  	/* IPv6 specs say nothing about it, but it is clear that we cannot
  	   send redirects to source routed frames.
  	 */
  	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
  		struct in6_addr *target = NULL;
  		struct rt6_info *rt;
  		struct neighbour *n = dst->neighbour;
  
  		/*
  		 *	incoming and outgoing devices are the same
  		 *	send a redirect.
  		 */
  
  		rt = (struct rt6_info *) dst;
  		if ((rt->rt6i_flags & RTF_GATEWAY))
  			target = (struct in6_addr*)&n->primary_key;
  		else
  			target = &hdr->daddr;
  
  		/* Limit redirects both by destination (here)
  		   and by source (inside ndisc_send_redirect)
  		 */
  		if (xrlim_allow(dst, 1*HZ))
  			ndisc_send_redirect(skb, n, target);

  	} else {
  		int addrtype = ipv6_addr_type(&hdr->saddr);

  		/* This check is security critical. */

  		if (addrtype & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK))
  			goto error;
  		if (addrtype & IPV6_ADDR_LINKLOCAL) {
  			icmpv6_send(skb, ICMPV6_DEST_UNREACH,
  				ICMPV6_NOT_NEIGHBOUR, 0, skb->dev);
  			goto error;
  		}

  	}
  
  	if (skb->len > dst_mtu(dst)) {
  		/* Again, force OUTPUT device used as source address */
  		skb->dev = dst->dev;
  		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);

  		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS);
  		IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS);

  		kfree_skb(skb);
  		return -EMSGSIZE;
  	}
  
  	if (skb_cow(skb, dst->dev->hard_header_len)) {

  		IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);

  		goto drop;
  	}

  	hdr = ipv6_hdr(skb);

  
  	/* Mangling hops number delayed to point after skb COW */

  	hdr->hop_limit--;

  	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);

  	return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish);
  
  error:

  	IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);

  drop:
  	kfree_skb(skb);
  	return -EINVAL;
  }
  
  static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
  {
  	to->pkt_type = from->pkt_type;
  	to->priority = from->priority;
  	to->protocol = from->protocol;

  	dst_release(to->dst);
  	to->dst = dst_clone(from->dst);
  	to->dev = from->dev;

  	to->mark = from->mark;

  
  #ifdef CONFIG_NET_SCHED
  	to->tc_index = from->tc_index;
  #endif

  	nf_copy(to, from);

  #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
      defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
  	to->nf_trace = from->nf_trace;
  #endif

  	skb_copy_secmark(to, from);

  }
  
  int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
  {
  	u16 offset = sizeof(struct ipv6hdr);

  	struct ipv6_opt_hdr *exthdr =
  				(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);

  	unsigned int packet_len = skb->tail - skb->network_header;

  	int found_rhdr = 0;

  	*nexthdr = &ipv6_hdr(skb)->nexthdr;

  
  	while (offset + 1 <= packet_len) {
  
  		switch (**nexthdr) {
  
  		case NEXTHDR_HOP:

  			break;

  		case NEXTHDR_ROUTING:

  			found_rhdr = 1;
  			break;

  		case NEXTHDR_DEST:

  #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)

  			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
  				break;
  #endif
  			if (found_rhdr)
  				return offset;

  			break;
  		default :
  			return offset;
  		}

  
  		offset += ipv6_optlen(exthdr);
  		*nexthdr = &exthdr->nexthdr;

  		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
  						 offset);

  	}
  
  	return offset;
  }

  EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);

  
  static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
  {
  	struct net_device *dev;
  	struct sk_buff *frag;
  	struct rt6_info *rt = (struct rt6_info*)skb->dst;

  	struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;

  	struct ipv6hdr *tmp_hdr;
  	struct frag_hdr *fh;
  	unsigned int mtu, hlen, left, len;

  	__be32 frag_id = 0;

  	int ptr, offset = 0, err=0;
  	u8 *prevhdr, nexthdr = 0;
  
  	dev = rt->u.dst.dev;
  	hlen = ip6_find_1stfragopt(skb, &prevhdr);
  	nexthdr = *prevhdr;

  	mtu = ip6_skb_dst_mtu(skb);

  
  	/* We must not fragment if the socket is set to force MTU discovery
  	 * or if the skb it not generated by a local socket.  (This last
  	 * check should be redundant, but it's free.)
  	 */
  	if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) {
  		skb->dev = skb->dst->dev;
  		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
  		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
  		kfree_skb(skb);
  		return -EMSGSIZE;
  	}

  	if (np && np->frag_size < mtu) {
  		if (np->frag_size)
  			mtu = np->frag_size;
  	}
  	mtu -= hlen + sizeof(struct frag_hdr);

  
  	if (skb_shinfo(skb)->frag_list) {
  		int first_len = skb_pagelen(skb);
  
  		if (first_len - hlen > mtu ||
  		    ((first_len - hlen) & 7) ||
  		    skb_cloned(skb))
  			goto slow_path;
  
  		for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
  			/* Correct geometry. */
  			if (frag->len > mtu ||
  			    ((frag->len & 7) && frag->next) ||
  			    skb_headroom(frag) < hlen)
  			    goto slow_path;

  			/* Partially cloned skb? */
  			if (skb_shared(frag))
  				goto slow_path;

  
  			BUG_ON(frag->sk);
  			if (skb->sk) {
  				sock_hold(skb->sk);
  				frag->sk = skb->sk;
  				frag->destructor = sock_wfree;
  				skb->truesize -= frag->truesize;
  			}

  		}
  
  		err = 0;
  		offset = 0;
  		frag = skb_shinfo(skb)->frag_list;
  		skb_shinfo(skb)->frag_list = NULL;
  		/* BUILD HEADER */

  		*prevhdr = NEXTHDR_FRAGMENT;

  		tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);

  		if (!tmp_hdr) {

  			IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);

  			return -ENOMEM;
  		}

  		__skb_pull(skb, hlen);
  		fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));

  		__skb_push(skb, hlen);
  		skb_reset_network_header(skb);

  		memcpy(skb_network_header(skb), tmp_hdr, hlen);

  
  		ipv6_select_ident(skb, fh);
  		fh->nexthdr = nexthdr;
  		fh->reserved = 0;
  		fh->frag_off = htons(IP6_MF);
  		frag_id = fh->identification;
  
  		first_len = skb_pagelen(skb);
  		skb->data_len = first_len - skb_headlen(skb);
  		skb->len = first_len;

  		ipv6_hdr(skb)->payload_len = htons(first_len -
  						   sizeof(struct ipv6hdr));

  
  		dst_hold(&rt->u.dst);

  
  		for (;;) {
  			/* Prepare header of the next frame,
  			 * before previous one went down. */
  			if (frag) {
  				frag->ip_summed = CHECKSUM_NONE;

  				skb_reset_transport_header(frag);

  				fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));

  				__skb_push(frag, hlen);
  				skb_reset_network_header(frag);

  				memcpy(skb_network_header(frag), tmp_hdr,
  				       hlen);

  				offset += skb->len - hlen - sizeof(struct frag_hdr);
  				fh->nexthdr = nexthdr;
  				fh->reserved = 0;
  				fh->frag_off = htons(offset);
  				if (frag->next != NULL)
  					fh->frag_off |= htons(IP6_MF);
  				fh->identification = frag_id;

  				ipv6_hdr(frag)->payload_len =
  						htons(frag->len -
  						      sizeof(struct ipv6hdr));

  				ip6_copy_metadata(frag, skb);
  			}

  			err = output(skb);

  			if(!err)

  				IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGCREATES);

  			if (err || !frag)
  				break;
  
  			skb = frag;
  			frag = skb->next;
  			skb->next = NULL;
  		}

  		kfree(tmp_hdr);

  
  		if (err == 0) {

  			IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGOKS);
  			dst_release(&rt->u.dst);

  			return 0;
  		}
  
  		while (frag) {
  			skb = frag->next;
  			kfree_skb(frag);
  			frag = skb;
  		}

  		IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGFAILS);
  		dst_release(&rt->u.dst);

  		return err;
  	}
  
  slow_path:
  	left = skb->len - hlen;		/* Space per frame */
  	ptr = hlen;			/* Where to start from */
  
  	/*
  	 *	Fragment the datagram.
  	 */
  
  	*prevhdr = NEXTHDR_FRAGMENT;
  
  	/*
  	 *	Keep copying data until we run out.
  	 */
  	while(left > 0)	{
  		len = left;
  		/* IF: it doesn't fit, use 'mtu' - the data space left */
  		if (len > mtu)
  			len = mtu;
  		/* IF: we are not sending upto and including the packet end
  		   then align the next start on an eight byte boundary */
  		if (len < left)	{
  			len &= ~7;
  		}
  		/*
  		 *	Allocate buffer.
  		 */
  
  		if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {

  			NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!
  ");

  			IP6_INC_STATS(ip6_dst_idev(skb->dst),
  				      IPSTATS_MIB_FRAGFAILS);

  			err = -ENOMEM;
  			goto fail;
  		}
  
  		/*
  		 *	Set up data on packet
  		 */
  
  		ip6_copy_metadata(frag, skb);
  		skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
  		skb_put(frag, len + hlen + sizeof(struct frag_hdr));

  		skb_reset_network_header(frag);

  		fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);

  		frag->transport_header = (frag->network_header + hlen +
  					  sizeof(struct frag_hdr));

  
  		/*
  		 *	Charge the memory for the fragment to any owner
  		 *	it might possess
  		 */
  		if (skb->sk)
  			skb_set_owner_w(frag, skb->sk);
  
  		/*
  		 *	Copy the packet header into the new buffer.
  		 */

  		skb_copy_from_linear_data(skb, skb_network_header(frag), hlen);

  
  		/*
  		 *	Build fragment header.
  		 */
  		fh->nexthdr = nexthdr;
  		fh->reserved = 0;

  		if (!frag_id) {

  			ipv6_select_ident(skb, fh);
  			frag_id = fh->identification;
  		} else
  			fh->identification = frag_id;
  
  		/*
  		 *	Copy a block of the IP datagram.
  		 */

  		if (skb_copy_bits(skb, ptr, skb_transport_header(skb), len))

  			BUG();
  		left -= len;
  
  		fh->frag_off = htons(offset);
  		if (left > 0)
  			fh->frag_off |= htons(IP6_MF);

  		ipv6_hdr(frag)->payload_len = htons(frag->len -
  						    sizeof(struct ipv6hdr));

  
  		ptr += len;
  		offset += len;
  
  		/*
  		 *	Put this fragment into the sending queue.
  		 */

  		err = output(frag);
  		if (err)
  			goto fail;

  		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGCREATES);

  	}

  	IP6_INC_STATS(ip6_dst_idev(skb->dst),
  		      IPSTATS_MIB_FRAGOKS);

  	kfree_skb(skb);

  	return err;
  
  fail:

  	IP6_INC_STATS(ip6_dst_idev(skb->dst),
  		      IPSTATS_MIB_FRAGFAILS);

  	kfree_skb(skb);

  	return err;
  }

  static inline int ip6_rt_check(struct rt6key *rt_key,
  			       struct in6_addr *fl_addr,
  			       struct in6_addr *addr_cache)
  {
  	return ((rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) &&
  		(addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache)));
  }

  static struct dst_entry *ip6_sk_dst_check(struct sock *sk,
  					  struct dst_entry *dst,
  					  struct flowi *fl)

  {

  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct rt6_info *rt = (struct rt6_info *)dst;

  	if (!dst)
  		goto out;
  
  	/* Yes, checking route validity in not connected
  	 * case is not very simple. Take into account,
  	 * that we do not support routing by source, TOS,
  	 * and MSG_DONTROUTE 		--ANK (980726)
  	 *

  	 * 1. ip6_rt_check(): If route was host route,
  	 *    check that cached destination is current.

  	 *    If it is network route, we still may
  	 *    check its validity using saved pointer
  	 *    to the last used address: daddr_cache.
  	 *    We do not want to save whole address now,
  	 *    (because main consumer of this service
  	 *    is tcp, which has not this problem),
  	 *    so that the last trick works only on connected
  	 *    sockets.
  	 * 2. oif also should be the same.
  	 */

  	if (ip6_rt_check(&rt->rt6i_dst, &fl->fl6_dst, np->daddr_cache) ||

  #ifdef CONFIG_IPV6_SUBTREES
  	    ip6_rt_check(&rt->rt6i_src, &fl->fl6_src, np->saddr_cache) ||
  #endif

  	    (fl->oif && fl->oif != dst->dev->ifindex)) {

  		dst_release(dst);
  		dst = NULL;

  	}

  out:
  	return dst;
  }
  
  static int ip6_dst_lookup_tail(struct sock *sk,
  			       struct dst_entry **dst, struct flowi *fl)
  {
  	int err;

  	if (*dst == NULL)
  		*dst = ip6_route_output(sk, fl);
  
  	if ((err = (*dst)->error))
  		goto out_err_release;
  
  	if (ipv6_addr_any(&fl->fl6_src)) {
  		err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);

  		if (err)

  			goto out_err_release;

  	}

  #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
  		/*
  		 * Here if the dst entry we've looked up
  		 * has a neighbour entry that is in the INCOMPLETE
  		 * state and the src address from the flow is
  		 * marked as OPTIMISTIC, we release the found
  		 * dst entry and replace it instead with the
  		 * dst entry of the nexthop router
  		 */
  		if (!((*dst)->neighbour->nud_state & NUD_VALID)) {
  			struct inet6_ifaddr *ifp;
  			struct flowi fl_gw;
  			int redirect;
  
  			ifp = ipv6_get_ifaddr(&fl->fl6_src, (*dst)->dev, 1);
  
  			redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC);
  			if (ifp)
  				in6_ifa_put(ifp);
  
  			if (redirect) {
  				/*
  				 * We need to get the dst entry for the
  				 * default router instead
  				 */
  				dst_release(*dst);
  				memcpy(&fl_gw, fl, sizeof(struct flowi));
  				memset(&fl_gw.fl6_dst, 0, sizeof(struct in6_addr));
  				*dst = ip6_route_output(sk, &fl_gw);
  				if ((err = (*dst)->error))
  					goto out_err_release;
  			}
  		}
  #endif

  	return 0;
  
  out_err_release:
  	dst_release(*dst);
  	*dst = NULL;
  	return err;
  }

  /**
   *	ip6_dst_lookup - perform route lookup on flow
   *	@sk: socket which provides route info
   *	@dst: pointer to dst_entry * for result
   *	@fl: flow to lookup
   *
   *	This function performs a route lookup on the given flow.
   *
   *	It returns zero on success, or a standard errno code on error.
   */
  int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
  {
  	*dst = NULL;
  	return ip6_dst_lookup_tail(sk, dst, fl);
  }

  EXPORT_SYMBOL_GPL(ip6_dst_lookup);

  /**
   *	ip6_sk_dst_lookup - perform socket cached route lookup on flow
   *	@sk: socket which provides the dst cache and route info
   *	@dst: pointer to dst_entry * for result
   *	@fl: flow to lookup
   *
   *	This function performs a route lookup on the given flow with the
   *	possibility of using the cached route in the socket if it is valid.
   *	It will take the socket dst lock when operating on the dst cache.
   *	As a result, this function can only be used in process context.
   *
   *	It returns zero on success, or a standard errno code on error.
   */
  int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
  {
  	*dst = NULL;
  	if (sk) {
  		*dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie);
  		*dst = ip6_sk_dst_check(sk, *dst, fl);
  	}
  
  	return ip6_dst_lookup_tail(sk, dst, fl);
  }
  EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup);

  static inline int ip6_ufo_append_data(struct sock *sk,

  			int getfrag(void *from, char *to, int offset, int len,
  			int odd, struct sk_buff *skb),
  			void *from, int length, int hh_len, int fragheaderlen,
  			int transhdrlen, int mtu,unsigned int flags)
  
  {
  	struct sk_buff *skb;
  	int err;
  
  	/* There is support for UDP large send offload by network
  	 * device, so create one single skb packet containing complete
  	 * udp datagram
  	 */
  	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
  		skb = sock_alloc_send_skb(sk,
  			hh_len + fragheaderlen + transhdrlen + 20,
  			(flags & MSG_DONTWAIT), &err);
  		if (skb == NULL)
  			return -ENOMEM;
  
  		/* reserve space for Hardware header */
  		skb_reserve(skb, hh_len);
  
  		/* create space for UDP/IP header */
  		skb_put(skb,fragheaderlen + transhdrlen);
  
  		/* initialize network header pointer */

  		skb_reset_network_header(skb);

  
  		/* initialize protocol header pointer */

  		skb->transport_header = skb->network_header + fragheaderlen;

  		skb->ip_summed = CHECKSUM_PARTIAL;

  		skb->csum = 0;
  		sk->sk_sndmsg_off = 0;
  	}
  
  	err = skb_append_datato_frags(sk,skb, getfrag, from,
  				      (length - transhdrlen));
  	if (!err) {
  		struct frag_hdr fhdr;
  
  		/* specify the length of each IP datagram fragment*/

  		skb_shinfo(skb)->gso_size = mtu - fragheaderlen -

  					    sizeof(struct frag_hdr);

  		skb_shinfo(skb)->gso_type = SKB_GSO_UDP;

  		ipv6_select_ident(skb, &fhdr);
  		skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
  		__skb_queue_tail(&sk->sk_write_queue, skb);
  
  		return 0;
  	}
  	/* There is not enough support do UPD LSO,
  	 * so follow normal path
  	 */
  	kfree_skb(skb);
  
  	return err;
  }

  int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
  	int offset, int len, int odd, struct sk_buff *skb),
  	void *from, int length, int transhdrlen,
  	int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
  	struct rt6_info *rt, unsigned int flags)

  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct sk_buff *skb;
  	unsigned int maxfraglen, fragheaderlen;
  	int exthdrlen;
  	int hh_len;
  	int mtu;
  	int copy;
  	int err;
  	int offset = 0;
  	int csummode = CHECKSUM_NONE;
  
  	if (flags&MSG_PROBE)
  		return 0;
  	if (skb_queue_empty(&sk->sk_write_queue)) {
  		/*
  		 * setup for corking
  		 */
  		if (opt) {
  			if (np->cork.opt == NULL) {
  				np->cork.opt = kmalloc(opt->tot_len,
  						       sk->sk_allocation);
  				if (unlikely(np->cork.opt == NULL))
  					return -ENOBUFS;
  			} else if (np->cork.opt->tot_len < opt->tot_len) {
  				printk(KERN_DEBUG "ip6_append_data: invalid option length
  ");
  				return -EINVAL;
  			}
  			memcpy(np->cork.opt, opt, opt->tot_len);
  			inet->cork.flags |= IPCORK_OPT;
  			/* need source address above miyazawa*/
  		}
  		dst_hold(&rt->u.dst);
  		np->cork.rt = rt;
  		inet->cork.fl = *fl;
  		np->cork.hop_limit = hlimit;

  		np->cork.tclass = tclass;

  		mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ?
  		      rt->u.dst.dev->mtu : dst_mtu(rt->u.dst.path);

  		if (np->frag_size < mtu) {

  			if (np->frag_size)
  				mtu = np->frag_size;
  		}
  		inet->cork.fragsize = mtu;

  		if (dst_allfrag(rt->u.dst.path))
  			inet->cork.flags |= IPCORK_ALLFRAG;
  		inet->cork.length = 0;
  		sk->sk_sndmsg_page = NULL;
  		sk->sk_sndmsg_off = 0;
  		exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0);
  		length += exthdrlen;
  		transhdrlen += exthdrlen;
  	} else {
  		rt = np->cork.rt;
  		fl = &inet->cork.fl;
  		if (inet->cork.flags & IPCORK_OPT)
  			opt = np->cork.opt;
  		transhdrlen = 0;
  		exthdrlen = 0;
  		mtu = inet->cork.fragsize;
  	}
  
  	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);

  	fragheaderlen = sizeof(struct ipv6hdr) + rt->u.dst.nfheader_len + (opt ? opt->opt_nflen : 0);

  	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
  
  	if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
  		if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
  			ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
  			return -EMSGSIZE;
  		}
  	}
  
  	/*
  	 * Let's try using as much space as possible.
  	 * Use MTU if total length of the message fits into the MTU.
  	 * Otherwise, we need to reserve fragment header and
  	 * fragment alignment (= 8-15 octects, in total).
  	 *
  	 * Note that we may need to "move" the data from the tail of

  	 * of the buffer to the new fragment when we split

  	 * the message.
  	 *

  	 * FIXME: It may be fragmented into multiple chunks

  	 *        at once if non-fragmentable extension headers
  	 *        are too large.

  	 * --yoshfuji

  	 */
  
  	inet->cork.length += length;

  	if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
  	    (rt->u.dst.dev->features & NETIF_F_UFO)) {

  		err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
  					  fragheaderlen, transhdrlen, mtu,
  					  flags);
  		if (err)

  			goto error;

  		return 0;
  	}

  
  	if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
  		goto alloc_new_skb;
  
  	while (length > 0) {
  		/* Check if the remaining data fits into current packet. */
  		copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
  		if (copy < length)
  			copy = maxfraglen - skb->len;
  
  		if (copy <= 0) {
  			char *data;
  			unsigned int datalen;
  			unsigned int fraglen;
  			unsigned int fraggap;
  			unsigned int alloclen;
  			struct sk_buff *skb_prev;
  alloc_new_skb:
  			skb_prev = skb;
  
  			/* There's no room in the current skb */
  			if (skb_prev)
  				fraggap = skb_prev->len - maxfraglen;
  			else
  				fraggap = 0;
  
  			/*
  			 * If remaining data exceeds the mtu,
  			 * we know we need more fragment(s).
  			 */
  			datalen = length + fraggap;
  			if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
  				datalen = maxfraglen - fragheaderlen;
  
  			fraglen = datalen + fragheaderlen;
  			if ((flags & MSG_MORE) &&
  			    !(rt->u.dst.dev->features&NETIF_F_SG))
  				alloclen = mtu;
  			else
  				alloclen = datalen + fragheaderlen;
  
  			/*
  			 * The last fragment gets additional space at tail.
  			 * Note: we overallocate on fragments with MSG_MODE
  			 * because we have no idea if we're the last one.
  			 */
  			if (datalen == length + fraggap)
  				alloclen += rt->u.dst.trailer_len;
  
  			/*
  			 * We just reserve space for fragment header.

  			 * Note: this may be overallocation if the message

  			 * (without MSG_MORE) fits into the MTU.
  			 */
  			alloclen += sizeof(struct frag_hdr);
  
  			if (transhdrlen) {
  				skb = sock_alloc_send_skb(sk,
  						alloclen + hh_len,
  						(flags & MSG_DONTWAIT), &err);
  			} else {
  				skb = NULL;
  				if (atomic_read(&sk->sk_wmem_alloc) <=
  				    2 * sk->sk_sndbuf)
  					skb = sock_wmalloc(sk,
  							   alloclen + hh_len, 1,
  							   sk->sk_allocation);
  				if (unlikely(skb == NULL))
  					err = -ENOBUFS;
  			}
  			if (skb == NULL)
  				goto error;
  			/*
  			 *	Fill in the control structures
  			 */
  			skb->ip_summed = csummode;
  			skb->csum = 0;
  			/* reserve for fragmentation */
  			skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
  
  			/*
  			 *	Find where to start putting bytes
  			 */
  			data = skb_put(skb, fraglen);

  			skb_set_network_header(skb, exthdrlen);

  			data += fragheaderlen;

  			skb->transport_header = (skb->network_header +
  						 fragheaderlen);

  			if (fraggap) {
  				skb->csum = skb_copy_and_csum_bits(
  					skb_prev, maxfraglen,
  					data + transhdrlen, fraggap, 0);
  				skb_prev->csum = csum_sub(skb_prev->csum,
  							  skb->csum);
  				data += fraggap;

  				pskb_trim_unique(skb_prev, maxfraglen);

  			}
  			copy = datalen - transhdrlen - fraggap;
  			if (copy < 0) {
  				err = -EINVAL;
  				kfree_skb(skb);
  				goto error;
  			} else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
  				err = -EFAULT;
  				kfree_skb(skb);
  				goto error;
  			}
  
  			offset += copy;
  			length -= datalen - fraggap;
  			transhdrlen = 0;
  			exthdrlen = 0;
  			csummode = CHECKSUM_NONE;
  
  			/*
  			 * Put the packet on the pending queue
  			 */
  			__skb_queue_tail(&sk->sk_write_queue, skb);
  			continue;
  		}
  
  		if (copy > length)
  			copy = length;
  
  		if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
  			unsigned int off;
  
  			off = skb->len;
  			if (getfrag(from, skb_put(skb, copy),
  						offset, copy, off, skb) < 0) {
  				__skb_trim(skb, off);
  				err = -EFAULT;
  				goto error;
  			}
  		} else {
  			int i = skb_shinfo(skb)->nr_frags;
  			skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
  			struct page *page = sk->sk_sndmsg_page;
  			int off = sk->sk_sndmsg_off;
  			unsigned int left;
  
  			if (page && (left = PAGE_SIZE - off) > 0) {
  				if (copy >= left)
  					copy = left;
  				if (page != frag->page) {
  					if (i == MAX_SKB_FRAGS) {
  						err = -EMSGSIZE;
  						goto error;
  					}
  					get_page(page);
  					skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
  					frag = &skb_shinfo(skb)->frags[i];
  				}
  			} else if(i < MAX_SKB_FRAGS) {
  				if (copy > PAGE_SIZE)
  					copy = PAGE_SIZE;
  				page = alloc_pages(sk->sk_allocation, 0);
  				if (page == NULL) {
  					err = -ENOMEM;
  					goto error;
  				}
  				sk->sk_sndmsg_page = page;
  				sk->sk_sndmsg_off = 0;
  
  				skb_fill_page_desc(skb, i, page, 0, 0);
  				frag = &skb_shinfo(skb)->frags[i];
  				skb->truesize += PAGE_SIZE;
  				atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
  			} else {
  				err = -EMSGSIZE;
  				goto error;
  			}
  			if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
  				err = -EFAULT;
  				goto error;
  			}
  			sk->sk_sndmsg_off += copy;
  			frag->size += copy;
  			skb->len += copy;
  			skb->data_len += copy;
  		}
  		offset += copy;
  		length -= copy;
  	}
  	return 0;
  error:
  	inet->cork.length -= length;

  	IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS);

  	return err;
  }
  
  int ip6_push_pending_frames(struct sock *sk)
  {
  	struct sk_buff *skb, *tmp_skb;
  	struct sk_buff **tail_skb;
  	struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct ipv6hdr *hdr;
  	struct ipv6_txoptions *opt = np->cork.opt;
  	struct rt6_info *rt = np->cork.rt;
  	struct flowi *fl = &inet->cork.fl;
  	unsigned char proto = fl->proto;
  	int err = 0;
  
  	if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
  		goto out;
  	tail_skb = &(skb_shinfo(skb)->frag_list);
  
  	/* move skb->data to ip header from ext header */

  	if (skb->data < skb_network_header(skb))

  		__skb_pull(skb, skb_network_offset(skb));

  	while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {

  		__skb_pull(tmp_skb, skb_network_header_len(skb));

  		*tail_skb = tmp_skb;
  		tail_skb = &(tmp_skb->next);
  		skb->len += tmp_skb->len;
  		skb->data_len += tmp_skb->len;

  		skb->truesize += tmp_skb->truesize;
  		__sock_put(tmp_skb->sk);
  		tmp_skb->destructor = NULL;
  		tmp_skb->sk = NULL;

  	}
  
  	ipv6_addr_copy(final_dst, &fl->fl6_dst);

  	__skb_pull(skb, skb_network_header_len(skb));

  	if (opt && opt->opt_flen)
  		ipv6_push_frag_opts(skb, opt, &proto);
  	if (opt && opt->opt_nflen)
  		ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);

  	skb_push(skb, sizeof(struct ipv6hdr));
  	skb_reset_network_header(skb);

  	hdr = ipv6_hdr(skb);

  	*(__be32*)hdr = fl->fl6_flowlabel |

  		     htonl(0x60000000 | ((int)np->cork.tclass << 20));

  
  	if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN)
  		hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
  	else
  		hdr->payload_len = 0;
  	hdr->hop_limit = np->cork.hop_limit;
  	hdr->nexthdr = proto;
  	ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
  	ipv6_addr_copy(&hdr->daddr, final_dst);

  	skb->priority = sk->sk_priority;

  	skb->dst = dst_clone(&rt->u.dst);

  	IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS);

  	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output);
  	if (err) {
  		if (err > 0)

  			err = np->recverr ? net_xmit_errno(err) : 0;

  		if (err)
  			goto error;
  	}
  
  out:
  	inet->cork.flags &= ~IPCORK_OPT;

  	kfree(np->cork.opt);
  	np->cork.opt = NULL;

  	if (np->cork.rt) {
  		dst_release(&np->cork.rt->u.dst);
  		np->cork.rt = NULL;
  		inet->cork.flags &= ~IPCORK_ALLFRAG;
  	}
  	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
  	return err;
  error:
  	goto out;
  }
  
  void ip6_flush_pending_frames(struct sock *sk)
  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct sk_buff *skb;
  
  	while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {

  		IP6_INC_STATS(ip6_dst_idev(skb->dst),
  			      IPSTATS_MIB_OUTDISCARDS);

  		kfree_skb(skb);
  	}
  
  	inet->cork.flags &= ~IPCORK_OPT;

  	kfree(np->cork.opt);
  	np->cork.opt = NULL;

  	if (np->cork.rt) {
  		dst_release(&np->cork.rt->u.dst);
  		np->cork.rt = NULL;
  		inet->cork.flags &= ~IPCORK_ALLFRAG;
  	}
  	memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
  }