/*
   * Copyright (C)2002 USAGI/WIDE Project

   *

   * 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.

   *

   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.

   *

   * You should have received a copy of the GNU General Public License

   * along with this program; if not, see <http://www.gnu.org/licenses/>.

   *
   * Authors
   *

   *	Mitsuru KANDA @USAGI       : IPv6 Support

   *	Kazunori MIYAZAWA @USAGI   :
   *	Kunihiro Ishiguro <kunihiro@ipinfusion.com>

   *

   *	This file is derived from net/ipv4/esp.c

   */

  #define pr_fmt(fmt) "IPv6: " fmt

  #include <crypto/aead.h>
  #include <crypto/authenc.h>

  #include <linux/err.h>

  #include <linux/module.h>
  #include <net/ip.h>
  #include <net/xfrm.h>
  #include <net/esp.h>

  #include <linux/scatterlist.h>

  #include <linux/kernel.h>

  #include <linux/pfkeyv2.h>
  #include <linux/random.h>

  #include <linux/slab.h>

  #include <linux/spinlock.h>

  #include <net/ip6_route.h>

  #include <net/icmp.h>
  #include <net/ipv6.h>

  #include <net/protocol.h>

  #include <linux/icmpv6.h>

  #include <linux/highmem.h>

  struct esp_skb_cb {
  	struct xfrm_skb_cb xfrm;
  	void *tmp;
  };
  
  #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))

  static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);

  /*
   * Allocate an AEAD request structure with extra space for SG and IV.
   *

   * For alignment considerations the upper 32 bits of the sequence number are
   * placed at the front, if present. Followed by the IV, the request and finally
   * the SG list.

   *
   * TODO: Use spare space in skb for this where possible.
   */

  static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)

  {
  	unsigned int len;

  	len = seqihlen;
  
  	len += crypto_aead_ivsize(aead);

  	if (len) {
  		len += crypto_aead_alignmask(aead) &
  		       ~(crypto_tfm_ctx_alignment() - 1);
  		len = ALIGN(len, crypto_tfm_ctx_alignment());
  	}

  	len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);

  	len = ALIGN(len, __alignof__(struct scatterlist));
  
  	len += sizeof(struct scatterlist) * nfrags;
  
  	return kmalloc(len, GFP_ATOMIC);
  }

  static inline __be32 *esp_tmp_seqhi(void *tmp)
  {
  	return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
  }
  
  static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)

  {
  	return crypto_aead_ivsize(aead) ?

  	       PTR_ALIGN((u8 *)tmp + seqhilen,
  			 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;

  }

  static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
  {
  	struct aead_request *req;
  
  	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
  				crypto_tfm_ctx_alignment());
  	aead_request_set_tfm(req, aead);
  	return req;
  }
  
  static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
  					     struct aead_request *req)
  {
  	return (void *)ALIGN((unsigned long)(req + 1) +
  			     crypto_aead_reqsize(aead),
  			     __alignof__(struct scatterlist));
  }

  static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
  {

  	struct crypto_aead *aead = x->data;
  	int seqhilen = 0;
  	u8 *iv;
  	struct aead_request *req;
  	struct scatterlist *sg;
  
  	if (x->props.flags & XFRM_STATE_ESN)
  		seqhilen += sizeof(__be32);

  	iv = esp_tmp_iv(aead, tmp, seqhilen);
  	req = esp_tmp_req(aead, iv);
  
  	/* Unref skb_frag_pages in the src scatterlist if necessary.
  	 * Skip the first sg which comes from skb->data.
  	 */
  	if (req->src != req->dst)
  		for (sg = sg_next(req->src); sg; sg = sg_next(sg))
  			put_page(sg_page(sg));
  }

  static void esp_output_done(struct crypto_async_request *base, int err)
  {
  	struct sk_buff *skb = base->data;

  	void *tmp;
  	struct dst_entry *dst = skb_dst(skb);
  	struct xfrm_state *x = dst->xfrm;

  	tmp = ESP_SKB_CB(skb)->tmp;
  	esp_ssg_unref(x, tmp);
  	kfree(tmp);

  	xfrm_output_resume(skb, err);
  }

  /* Move ESP header back into place. */
  static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
  {
  	struct ip_esp_hdr *esph = (void *)(skb->data + offset);
  	void *tmp = ESP_SKB_CB(skb)->tmp;
  	__be32 *seqhi = esp_tmp_seqhi(tmp);
  
  	esph->seq_no = esph->spi;
  	esph->spi = *seqhi;
  }
  
  static void esp_output_restore_header(struct sk_buff *skb)
  {
  	esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
  }

  static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,

  					     struct xfrm_state *x,

  					     struct ip_esp_hdr *esph,
  					     __be32 *seqhi)
  {

  	/* For ESN we move the header forward by 4 bytes to
  	 * accomodate the high bits.  We will move it back after
  	 * encryption.
  	 */
  	if ((x->props.flags & XFRM_STATE_ESN)) {

  		struct xfrm_offload *xo = xfrm_offload(skb);

  		esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
  		*seqhi = esph->spi;

  		if (xo)
  			esph->seq_no = htonl(xo->seq.hi);
  		else
  			esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);

  	}
  
  	esph->spi = x->id.spi;
  
  	return esph;
  }

  static void esp_output_done_esn(struct crypto_async_request *base, int err)
  {
  	struct sk_buff *skb = base->data;
  
  	esp_output_restore_header(skb);
  	esp_output_done(base, err);
  }

  static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
  {
  	/* Fill padding... */
  	if (tfclen) {
  		memset(tail, 0, tfclen);
  		tail += tfclen;
  	}
  	do {
  		int i;
  		for (i = 0; i < plen - 2; i++)
  			tail[i] = i + 1;
  	} while (0);
  	tail[plen - 2] = plen - 2;
  	tail[plen - 1] = proto;
  }

  int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)

  {

  	u8 *tail;

  	u8 *vaddr;

  	int nfrags;
  	struct page *page;

  	struct sk_buff *trailer;
  	int tailen = esp->tailen;

  	if (!skb_cloned(skb)) {

  		if (tailen <= skb_tailroom(skb)) {

  			nfrags = 1;
  			trailer = skb;
  			tail = skb_tail_pointer(trailer);
  
  			goto skip_cow;
  		} else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
  			   && !skb_has_frag_list(skb)) {
  			int allocsize;
  			struct sock *sk = skb->sk;
  			struct page_frag *pfrag = &x->xfrag;

  			esp->inplace = false;

  			allocsize = ALIGN(tailen, L1_CACHE_BYTES);
  
  			spin_lock_bh(&x->lock);
  
  			if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
  				spin_unlock_bh(&x->lock);
  				goto cow;
  			}
  
  			page = pfrag->page;
  			get_page(page);
  
  			vaddr = kmap_atomic(page);
  
  			tail = vaddr + pfrag->offset;

  			esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);

  
  			kunmap_atomic(vaddr);
  
  			nfrags = skb_shinfo(skb)->nr_frags;
  
  			__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
  					     tailen);
  			skb_shinfo(skb)->nr_frags = ++nfrags;
  
  			pfrag->offset = pfrag->offset + allocsize;

  
  			spin_unlock_bh(&x->lock);

  			nfrags++;
  
  			skb->len += tailen;
  			skb->data_len += tailen;
  			skb->truesize += tailen;
  			if (sk)

  				refcount_add(tailen, &sk->sk_wmem_alloc);

  			goto out;

  		}

  	}

  cow:

  	nfrags = skb_cow_data(skb, tailen, &trailer);
  	if (nfrags < 0)
  		goto out;

  	tail = skb_tail_pointer(trailer);

  
  skip_cow:

  	esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
  	pskb_put(skb, trailer, tailen);

  out:
  	return nfrags;
  }
  EXPORT_SYMBOL_GPL(esp6_output_head);

  int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
  {
  	u8 *iv;
  	int alen;
  	void *tmp;
  	int ivlen;
  	int assoclen;
  	int seqhilen;
  	__be32 *seqhi;
  	struct page *page;
  	struct ip_esp_hdr *esph;
  	struct aead_request *req;
  	struct crypto_aead *aead;
  	struct scatterlist *sg, *dsg;
  	int err = -ENOMEM;
  
  	assoclen = sizeof(struct ip_esp_hdr);
  	seqhilen = 0;
  
  	if (x->props.flags & XFRM_STATE_ESN) {
  		seqhilen += sizeof(__be32);
  		assoclen += sizeof(__be32);
  	}

  	aead = x->data;
  	alen = crypto_aead_authsize(aead);
  	ivlen = crypto_aead_ivsize(aead);
  
  	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, seqhilen);

  	if (!tmp)

  		goto error;

  	seqhi = esp_tmp_seqhi(tmp);
  	iv = esp_tmp_iv(aead, tmp, seqhilen);
  	req = esp_tmp_req(aead, iv);
  	sg = esp_req_sg(aead, req);

  	if (esp->inplace)
  		dsg = sg;
  	else
  		dsg = &sg[esp->nfrags];
  
  	esph = esp_output_set_esn(skb, x, ip_esp_hdr(skb), seqhi);

  	sg_init_table(sg, esp->nfrags);

  	err = skb_to_sgvec(skb, sg,
  		           (unsigned char *)esph - skb->data,
  		           assoclen + ivlen + esp->clen + alen);
  	if (unlikely(err < 0))

  		goto error_free;

  
  	if (!esp->inplace) {
  		int allocsize;
  		struct page_frag *pfrag = &x->xfrag;
  
  		allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
  
  		spin_lock_bh(&x->lock);
  		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
  			spin_unlock_bh(&x->lock);

  			goto error_free;

  		}
  
  		skb_shinfo(skb)->nr_frags = 1;
  
  		page = pfrag->page;
  		get_page(page);
  		/* replace page frags in skb with new page */
  		__skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
  		pfrag->offset = pfrag->offset + allocsize;
  		spin_unlock_bh(&x->lock);
  
  		sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);

  		err = skb_to_sgvec(skb, dsg,
  			           (unsigned char *)esph - skb->data,
  			           assoclen + ivlen + esp->clen + alen);
  		if (unlikely(err < 0))

  			goto error_free;

  	}

  	if ((x->props.flags & XFRM_STATE_ESN))
  		aead_request_set_callback(req, 0, esp_output_done_esn, skb);
  	else
  		aead_request_set_callback(req, 0, esp_output_done, skb);

  	aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);

  	aead_request_set_ad(req, assoclen);

  	memset(iv, 0, ivlen);

  	memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),

  	       min(ivlen, 8));

  	ESP_SKB_CB(skb)->tmp = tmp;

  	err = crypto_aead_encrypt(req);
  
  	switch (err) {
  	case -EINPROGRESS:

  		goto error;

  	case -EBUSY:

  		err = NET_XMIT_DROP;

  		break;
  
  	case 0:
  		if ((x->props.flags & XFRM_STATE_ESN))
  			esp_output_restore_header(skb);
  	}

  	if (sg != dsg)
  		esp_ssg_unref(x, tmp);

  error_free:
  	kfree(tmp);

  error:
  	return err;
  }

  EXPORT_SYMBOL_GPL(esp6_output_tail);
  
  static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
  {
  	int alen;
  	int blksize;
  	struct ip_esp_hdr *esph;
  	struct crypto_aead *aead;
  	struct esp_info esp;
  
  	esp.inplace = true;
  
  	esp.proto = *skb_mac_header(skb);
  	*skb_mac_header(skb) = IPPROTO_ESP;
  
  	/* skb is pure payload to encrypt */
  
  	aead = x->data;
  	alen = crypto_aead_authsize(aead);
  
  	esp.tfclen = 0;
  	if (x->tfcpad) {
  		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
  		u32 padto;
  
  		padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
  		if (skb->len < padto)
  			esp.tfclen = padto - skb->len;
  	}
  	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
  	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
  	esp.plen = esp.clen - skb->len - esp.tfclen;
  	esp.tailen = esp.tfclen + esp.plen + alen;
  
  	esp.nfrags = esp6_output_head(x, skb, &esp);
  	if (esp.nfrags < 0)
  		return esp.nfrags;
  
  	esph = ip_esp_hdr(skb);
  	esph->spi = x->id.spi;
  
  	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
  	esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
  			    ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
  
  	skb_push(skb, -skb_network_offset(skb));
  
  	return esp6_output_tail(x, skb, &esp);
  }

  static inline int esp_remove_trailer(struct sk_buff *skb)

  {
  	struct xfrm_state *x = xfrm_input_state(skb);

  	struct xfrm_offload *xo = xfrm_offload(skb);

  	struct crypto_aead *aead = x->data;

  	int alen, hlen, elen;

  	int padlen, trimlen;
  	__wsum csumdiff;

  	u8 nexthdr[2];

  	int ret;

  	alen = crypto_aead_authsize(aead);
  	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
  	elen = skb->len - hlen;

  	if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
  		ret = xo->proto;

  		goto out;

  	}

  	if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
  		BUG();

  	ret = -EINVAL;

  	padlen = nexthdr[0];
  	if (padlen + 2 + alen >= elen) {

  		net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d
  ",
  				    padlen + 2, elen - alen);

  		goto out;

  	}

  	trimlen = alen + padlen + 2;
  	if (skb->ip_summed == CHECKSUM_COMPLETE) {
  		csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
  		skb->csum = csum_block_sub(skb->csum, csumdiff,
  					   skb->len - trimlen);
  	}
  	pskb_trim(skb, skb->len - trimlen);

  	ret = nexthdr[1];
  
  out:
  	return ret;
  }
  
  int esp6_input_done2(struct sk_buff *skb, int err)
  {
  	struct xfrm_state *x = xfrm_input_state(skb);
  	struct xfrm_offload *xo = xfrm_offload(skb);
  	struct crypto_aead *aead = x->data;
  	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
  	int hdr_len = skb_network_header_len(skb);
  
  	if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
  		kfree(ESP_SKB_CB(skb)->tmp);
  
  	if (unlikely(err))
  		goto out;
  
  	err = esp_remove_trailer(skb);
  	if (unlikely(err < 0))
  		goto out;
  
  	skb_postpull_rcsum(skb, skb_network_header(skb),
  			   skb_network_header_len(skb));

  	skb_pull_rcsum(skb, hlen);

  	if (x->props.mode == XFRM_MODE_TUNNEL)
  		skb_reset_transport_header(skb);
  	else
  		skb_set_transport_header(skb, -hdr_len);

  	/* RFC4303: Drop dummy packets without any error */
  	if (err == IPPROTO_NONE)
  		err = -EINVAL;
  
  out:

  	return err;
  }

  EXPORT_SYMBOL_GPL(esp6_input_done2);

  static void esp_input_done(struct crypto_async_request *base, int err)
  {
  	struct sk_buff *skb = base->data;

  	xfrm_input_resume(skb, esp6_input_done2(skb, err));

  }

  static void esp_input_restore_header(struct sk_buff *skb)
  {
  	esp_restore_header(skb, 0);
  	__skb_pull(skb, 4);
  }

  static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
  {
  	struct xfrm_state *x = xfrm_input_state(skb);
  	struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data;
  
  	/* For ESN we move the header forward by 4 bytes to
  	 * accomodate the high bits.  We will move it back after
  	 * decryption.
  	 */
  	if ((x->props.flags & XFRM_STATE_ESN)) {

  		esph = skb_push(skb, 4);

  		*seqhi = esph->spi;
  		esph->spi = esph->seq_no;
  		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
  	}
  }

  static void esp_input_done_esn(struct crypto_async_request *base, int err)
  {
  	struct sk_buff *skb = base->data;
  
  	esp_input_restore_header(skb);
  	esp_input_done(base, err);
  }

  static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)

  {

  	struct ip_esp_hdr *esph;

  	struct crypto_aead *aead = x->data;

  	struct aead_request *req;

  	struct sk_buff *trailer;

  	int ivlen = crypto_aead_ivsize(aead);
  	int elen = skb->len - sizeof(*esph) - ivlen;

  	int nfrags;

  	int assoclen;

  	int seqhilen;

  	int ret = 0;

  	void *tmp;

  	__be32 *seqhi;

  	u8 *iv;
  	struct scatterlist *sg;

  	if (!pskb_may_pull(skb, sizeof(*esph) + ivlen)) {

  		ret = -EINVAL;

  		goto out;

  	}

  	if (elen <= 0) {

  		ret = -EINVAL;

  		goto out;

  	}

  	assoclen = sizeof(*esph);

  	seqhilen = 0;
  
  	if (x->props.flags & XFRM_STATE_ESN) {

  		seqhilen += sizeof(__be32);
  		assoclen += seqhilen;
  	}

  	if (!skb_cloned(skb)) {
  		if (!skb_is_nonlinear(skb)) {
  			nfrags = 1;
  
  			goto skip_cow;
  		} else if (!skb_has_frag_list(skb)) {
  			nfrags = skb_shinfo(skb)->nr_frags;
  			nfrags++;
  
  			goto skip_cow;
  		}
  	}
  
  	nfrags = skb_cow_data(skb, 0, &trailer);
  	if (nfrags < 0) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  skip_cow:
  	ret = -ENOMEM;

  	tmp = esp_alloc_tmp(aead, nfrags, seqhilen);

  	if (!tmp)
  		goto out;

  	ESP_SKB_CB(skb)->tmp = tmp;

  	seqhi = esp_tmp_seqhi(tmp);
  	iv = esp_tmp_iv(aead, tmp, seqhilen);

  	req = esp_tmp_req(aead, iv);

  	sg = esp_req_sg(aead, req);

  	esp_input_set_header(skb, seqhi);

  	sg_init_table(sg, nfrags);

  	ret = skb_to_sgvec(skb, sg, 0, skb->len);

  	if (unlikely(ret < 0)) {
  		kfree(tmp);

  		goto out;

  	}

  	skb->ip_summed = CHECKSUM_NONE;

  	if ((x->props.flags & XFRM_STATE_ESN))

  		aead_request_set_callback(req, 0, esp_input_done_esn, skb);

  	else
  		aead_request_set_callback(req, 0, esp_input_done, skb);

  
  	aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
  	aead_request_set_ad(req, assoclen);

  	ret = crypto_aead_decrypt(req);
  	if (ret == -EINPROGRESS)
  		goto out;

  	if ((x->props.flags & XFRM_STATE_ESN))
  		esp_input_restore_header(skb);

  	ret = esp6_input_done2(skb, ret);

  
  out:

  	return ret;
  }

  static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)

  {

  	struct crypto_aead *aead = x->data;
  	u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);

  	unsigned int net_adj;

  	if (x->props.mode != XFRM_MODE_TUNNEL)
  		net_adj = sizeof(struct ipv6hdr);
  	else
  		net_adj = 0;

  	return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -

  		 net_adj) & ~(blksize - 1)) + net_adj - 2;

  }

  static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  		    u8 type, u8 code, int offset, __be32 info)

  {

  	struct net *net = dev_net(skb->dev);

  	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;

  	struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);

  	struct xfrm_state *x;

  	if (type != ICMPV6_PKT_TOOBIG &&

  	    type != NDISC_REDIRECT)

  		return 0;

  	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
  			      esph->spi, IPPROTO_ESP, AF_INET6);

  	if (!x)

  		return 0;

  
  	if (type == NDISC_REDIRECT)

  		ip6_redirect(skb, net, skb->dev->ifindex, 0,
  			     sock_net_uid(net, NULL));

  	else

  		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));

  	xfrm_state_put(x);

  
  	return 0;

  }
  
  static void esp6_destroy(struct xfrm_state *x)
  {

  	struct crypto_aead *aead = x->data;

  	if (!aead)

  		return;

  	crypto_free_aead(aead);

  }

  static int esp_init_aead(struct xfrm_state *x)
  {

  	char aead_name[CRYPTO_MAX_ALG_NAME];

  	struct crypto_aead *aead;
  	int err;

  	u32 mask = 0;

  	err = -ENAMETOOLONG;
  	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
  		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
  		goto error;

  	if (x->xso.offload_handle)
  		mask |= CRYPTO_ALG_ASYNC;
  
  	aead = crypto_alloc_aead(aead_name, 0, mask);

  	err = PTR_ERR(aead);
  	if (IS_ERR(aead))
  		goto error;

  	x->data = aead;

  
  	err = crypto_aead_setkey(aead, x->aead->alg_key,
  				 (x->aead->alg_key_len + 7) / 8);
  	if (err)
  		goto error;
  
  	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
  	if (err)
  		goto error;
  
  error:
  	return err;
  }
  
  static int esp_init_authenc(struct xfrm_state *x)

  {

  	struct crypto_aead *aead;
  	struct crypto_authenc_key_param *param;
  	struct rtattr *rta;
  	char *key;
  	char *p;
  	char authenc_name[CRYPTO_MAX_ALG_NAME];

  	unsigned int keylen;
  	int err;

  	u32 mask = 0;

  	err = -EINVAL;

  	if (!x->ealg)

  		goto error;

  	err = -ENAMETOOLONG;

  
  	if ((x->props.flags & XFRM_STATE_ESN)) {
  		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,

  			     "%s%sauthencesn(%s,%s)%s",
  			     x->geniv ?: "", x->geniv ? "(" : "",

  			     x->aalg ? x->aalg->alg_name : "digest_null",

  			     x->ealg->alg_name,
  			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)

  			goto error;
  	} else {
  		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,

  			     "%s%sauthenc(%s,%s)%s",
  			     x->geniv ?: "", x->geniv ? "(" : "",

  			     x->aalg ? x->aalg->alg_name : "digest_null",

  			     x->ealg->alg_name,
  			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)

  			goto error;
  	}

  	if (x->xso.offload_handle)
  		mask |= CRYPTO_ALG_ASYNC;
  
  	aead = crypto_alloc_aead(authenc_name, 0, mask);

  	err = PTR_ERR(aead);
  	if (IS_ERR(aead))
  		goto error;

  	x->data = aead;

  
  	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
  		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
  	err = -ENOMEM;
  	key = kmalloc(keylen, GFP_KERNEL);
  	if (!key)
  		goto error;
  
  	p = key;
  	rta = (void *)p;
  	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
  	rta->rta_len = RTA_LENGTH(sizeof(*param));
  	param = RTA_DATA(rta);
  	p += RTA_SPACE(sizeof(*param));

  	if (x->aalg) {
  		struct xfrm_algo_desc *aalg_desc;

  		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
  		p += (x->aalg->alg_key_len + 7) / 8;

  		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
  		BUG_ON(!aalg_desc);

  		err = -EINVAL;

  		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=

  		    crypto_aead_authsize(aead)) {

  			pr_info("ESP: %s digestsize %u != %hu
  ",
  				x->aalg->alg_name,
  				crypto_aead_authsize(aead),
  				aalg_desc->uinfo.auth.icv_fullbits / 8);

  			goto free_key;

  		}

  		err = crypto_aead_setauthsize(

  			aead, x->aalg->alg_trunc_len / 8);

  		if (err)
  			goto free_key;

  	}

  	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
  	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
  
  	err = crypto_aead_setkey(aead, key, keylen);
  
  free_key:
  	kfree(key);

  error:
  	return err;
  }
  
  static int esp6_init_state(struct xfrm_state *x)
  {

  	struct crypto_aead *aead;
  	u32 align;
  	int err;
  
  	if (x->encap)
  		return -EINVAL;

  	x->data = NULL;

  
  	if (x->aead)
  		err = esp_init_aead(x);
  	else
  		err = esp_init_authenc(x);

  	if (err)

  		goto error;

  	aead = x->data;

  	x->props.header_len = sizeof(struct ip_esp_hdr) +
  			      crypto_aead_ivsize(aead);

  	switch (x->props.mode) {
  	case XFRM_MODE_BEET:

  		if (x->sel.family != AF_INET6)
  			x->props.header_len += IPV4_BEET_PHMAXLEN +

  					       (sizeof(struct ipv6hdr) - sizeof(struct iphdr));

  		break;

  	case XFRM_MODE_TRANSPORT:
  		break;
  	case XFRM_MODE_TUNNEL:

  		x->props.header_len += sizeof(struct ipv6hdr);

  		break;

  	default:
  		goto error;
  	}

  
  	align = ALIGN(crypto_aead_blocksize(aead), 4);

  	x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);

  
  error:

  	return err;

  }

  static int esp6_rcv_cb(struct sk_buff *skb, int err)
  {
  	return 0;
  }

  static const struct xfrm_type esp6_type = {

  	.description	= "ESP6",

  	.owner		= THIS_MODULE,
  	.proto		= IPPROTO_ESP,

  	.flags		= XFRM_TYPE_REPLAY_PROT,

  	.init_state	= esp6_init_state,
  	.destructor	= esp6_destroy,

  	.get_mtu	= esp6_get_mtu,

  	.input		= esp6_input,

  	.output		= esp6_output,
  	.hdr_offset	= xfrm6_find_1stfragopt,

  };

  static struct xfrm6_protocol esp6_protocol = {
  	.handler	=	xfrm6_rcv,
  	.cb_handler	=	esp6_rcv_cb,

  	.err_handler	=	esp6_err,

  	.priority	=	0,

  };
  
  static int __init esp6_init(void)
  {
  	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {

  		pr_info("%s: can't add xfrm type
  ", __func__);

  		return -EAGAIN;
  	}

  	if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {

  		pr_info("%s: can't add protocol
  ", __func__);

  		xfrm_unregister_type(&esp6_type, AF_INET6);
  		return -EAGAIN;
  	}
  
  	return 0;
  }
  
  static void __exit esp6_fini(void)
  {

  	if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)

  		pr_info("%s: can't remove protocol
  ", __func__);

  	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)

  		pr_info("%s: can't remove xfrm type
  ", __func__);

  }
  
  module_init(esp6_init);
  module_exit(esp6_fini);
  
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);