net/ipv6/esp6.c - kernel/msm-4.19 - Gitiles

 /*
  * 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, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  * 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>

 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_givcrypt_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_givcrypt_request *esp_tmp_givreq(
 	struct crypto_aead *aead, u8 *iv)
 {
 	struct aead_givcrypt_request *req;

 	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
 				crypto_tfm_ctx_alignment());
 	aead_givcrypt_set_tfm(req, aead);
 	return req;
 }

 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 inline struct scatterlist *esp_givreq_sg(
 	struct crypto_aead *aead, struct aead_givcrypt_request *req)
 {
 	return (void *)ALIGN((unsigned long)(req + 1) +
 			     crypto_aead_reqsize(aead),
 			     __alignof__(struct scatterlist));
 }

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

 	kfree(ESP_SKB_CB(skb)->tmp);
 	xfrm_output_resume(skb, err);
 }

 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err;
 	struct ip_esp_hdr *esph;
 	struct crypto_aead *aead;
 	struct aead_givcrypt_request *req;
 	struct scatterlist *sg;
 	struct scatterlist *asg;
 	struct sk_buff *trailer;
 	void *tmp;
 	int blksize;
 	int clen;
 	int alen;
 	int plen;
 	int tfclen;
 	int nfrags;
 	int assoclen;
 	int sglists;
 	int seqhilen;
 	u8 *iv;
 	u8 *tail;
 	__be32 *seqhi;
 	struct esp_data *esp = x->data;

 	/* skb is pure payload to encrypt */
 	aead = esp->aead;
 	alen = crypto_aead_authsize(aead);

 	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)
 			tfclen = padto - skb->len;
 	}
 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 	clen = ALIGN(skb->len + 2 + tfclen, blksize);
 	if (esp->padlen)
 		clen = ALIGN(clen, esp->padlen);
 	plen = clen - skb->len - tfclen;

 	err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
 	if (err < 0)
 		goto error;
 	nfrags = err;

 	assoclen = sizeof(*esph);
 	sglists = 1;
 	seqhilen = 0;

 	if (x->props.flags & XFRM_STATE_ESN) {
 		sglists += 2;
 		seqhilen += sizeof(__be32);
 		assoclen += seqhilen;
 	}

 	tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
 	if (!tmp) {
 		err = -ENOMEM;
 		goto error;
 	}

 	seqhi = esp_tmp_seqhi(tmp);
 	iv = esp_tmp_iv(aead, tmp, seqhilen);
 	req = esp_tmp_givreq(aead, iv);
 	asg = esp_givreq_sg(aead, req);
 	sg = asg + sglists;

 	/* Fill padding... */
 	tail = skb_tail_pointer(trailer);
 	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] = *skb_mac_header(skb);
 	pskb_put(skb, trailer, clen - skb->len + alen);

 	skb_push(skb, -skb_network_offset(skb));
 	esph = ip_esp_hdr(skb);
 	*skb_mac_header(skb) = IPPROTO_ESP;

 	esph->spi = x->id.spi;
 	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);

 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg,
 		     esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 		     clen + alen);

 	if ((x->props.flags & XFRM_STATE_ESN)) {
 		sg_init_table(asg, 3);
 		sg_set_buf(asg, &esph->spi, sizeof(__be32));
 		*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
 		sg_set_buf(asg + 1, seqhi, seqhilen);
 		sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 	} else
 		sg_init_one(asg, esph, sizeof(*esph));

 	aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
 	aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
 	aead_givcrypt_set_assoc(req, asg, assoclen);
 	aead_givcrypt_set_giv(req, esph->enc_data,
 			      XFRM_SKB_CB(skb)->seq.output.low);

 	ESP_SKB_CB(skb)->tmp = tmp;
 	err = crypto_aead_givencrypt(req);
 	if (err == -EINPROGRESS)
 		goto error;

 	if (err == -EBUSY)
 		err = NET_XMIT_DROP;

 	kfree(tmp);

 error:
 	return err;
 }

 static int esp_input_done2(struct sk_buff *skb, int err)
 {
 	struct xfrm_state *x = xfrm_input_state(skb);
 	struct esp_data *esp = x->data;
 	struct crypto_aead *aead = esp->aead;
 	int alen = crypto_aead_authsize(aead);
 	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
 	int elen = skb->len - hlen;
 	int hdr_len = skb_network_header_len(skb);
 	int padlen;
 	u8 nexthdr[2];

 	kfree(ESP_SKB_CB(skb)->tmp);

 	if (unlikely(err))
 		goto out;

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

 	err = -EINVAL;
 	padlen = nexthdr[0];
 	if (padlen + 2 + alen >= elen) {
 		LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
 			       "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
 		goto out;
 	}

 	/* ... check padding bits here. Silly. :-) */

 	pskb_trim(skb, skb->len - alen - padlen - 2);
 	__skb_pull(skb, hlen);
 	if (x->props.mode == XFRM_MODE_TUNNEL)
 		skb_reset_transport_header(skb);
 	else
 		skb_set_transport_header(skb, -hdr_len);

 	err = nexthdr[1];

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

 out:
 	return err;
 }

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

 	xfrm_input_resume(skb, esp_input_done2(skb, err));
 }

 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 {
 	struct ip_esp_hdr *esph;
 	struct esp_data *esp = x->data;
 	struct crypto_aead *aead = esp->aead;
 	struct aead_request *req;
 	struct sk_buff *trailer;
 	int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
 	int nfrags;
 	int assoclen;
 	int sglists;
 	int seqhilen;
 	int ret = 0;
 	void *tmp;
 	__be32 *seqhi;
 	u8 *iv;
 	struct scatterlist *sg;
 	struct scatterlist *asg;

 	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
 		ret = -EINVAL;
 		goto out;
 	}

 	if (elen <= 0) {
 		ret = -EINVAL;
 		goto out;
 	}

 	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
 		ret = -EINVAL;
 		goto out;
 	}

 	ret = -ENOMEM;

 	assoclen = sizeof(*esph);
 	sglists = 1;
 	seqhilen = 0;

 	if (x->props.flags & XFRM_STATE_ESN) {
 		sglists += 2;
 		seqhilen += sizeof(__be32);
 		assoclen += seqhilen;
 	}

 	tmp = esp_alloc_tmp(aead, nfrags + sglists, 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);
 	asg = esp_req_sg(aead, req);
 	sg = asg + sglists;

 	skb->ip_summed = CHECKSUM_NONE;

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

 	/* Get ivec. This can be wrong, check against another impls. */
 	iv = esph->enc_data;

 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);

 	if ((x->props.flags & XFRM_STATE_ESN)) {
 		sg_init_table(asg, 3);
 		sg_set_buf(asg, &esph->spi, sizeof(__be32));
 		*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
 		sg_set_buf(asg + 1, seqhi, seqhilen);
 		sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
 	} else
 		sg_init_one(asg, esph, sizeof(*esph));

 	aead_request_set_callback(req, 0, esp_input_done, skb);
 	aead_request_set_crypt(req, sg, sg, elen, iv);
 	aead_request_set_assoc(req, asg, assoclen);

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

 	ret = esp_input_done2(skb, ret);

 out:
 	return ret;
 }

 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
 {
 	struct esp_data *esp = x->data;
 	u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
 	u32 align = max_t(u32, blksize, esp->padlen);
 	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(esp->aead) -
 		 net_adj) & ~(align - 1)) + net_adj - 2;
 }

 static void 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_DEST_UNREACH &&
 	    type != ICMPV6_PKT_TOOBIG &&
 	    type != NDISC_REDIRECT)
 		return;

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

 	if (type == NDISC_REDIRECT)
 		ip6_redirect(skb, net, skb->dev->ifindex, 0);
 	else
 		ip6_update_pmtu(skb, net, info, 0, 0);
 	xfrm_state_put(x);
 }

 static void esp6_destroy(struct xfrm_state *x)
 {
 	struct esp_data *esp = x->data;

 	if (!esp)
 		return;

 	crypto_free_aead(esp->aead);
 	kfree(esp);
 }

 static int esp_init_aead(struct xfrm_state *x)
 {
 	struct esp_data *esp = x->data;
 	struct crypto_aead *aead;
 	int err;

 	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
 	err = PTR_ERR(aead);
 	if (IS_ERR(aead))
 		goto error;

 	esp->aead = 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 esp_data *esp = x->data;
 	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;

 	err = -EINVAL;
 	if (x->ealg == NULL)
 		goto error;

 	err = -ENAMETOOLONG;

 	if ((x->props.flags & XFRM_STATE_ESN)) {
 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 			     "authencesn(%s,%s)",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 			goto error;
 	} else {
 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
 			     "authenc(%s,%s)",
 			     x->aalg ? x->aalg->alg_name : "digest_null",
 			     x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
 			goto error;
 	}

 	aead = crypto_alloc_aead(authenc_name, 0, 0);
 	err = PTR_ERR(aead);
 	if (IS_ERR(aead))
 		goto error;

 	esp->aead = 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)) {
 			NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
 				 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 esp_data *esp;
 	struct crypto_aead *aead;
 	u32 align;
 	int err;

 	if (x->encap)
 		return -EINVAL;

 	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
 	if (esp == NULL)
 		return -ENOMEM;

 	x->data = esp;

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

 	if (err)
 		goto error;

 	aead = esp->aead;

 	esp->padlen = 0;

 	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);
 	if (esp->padlen)
 		align = max_t(u32, align, esp->padlen);
 	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);

 error:
 	return err;
 }

 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 const struct inet6_protocol esp6_protocol = {
 	.handler 	=	xfrm6_rcv,
 	.err_handler	=	esp6_err,
 	.flags		=	INET6_PROTO_NOPOLICY,
 };

 static int __init esp6_init(void)
 {
 	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
 		pr_info("%s: can't add xfrm type\n", __func__);
 		return -EAGAIN;
 	}
 	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
 		pr_info("%s: can't add protocol\n", __func__);
 		xfrm_unregister_type(&esp6_type, AF_INET6);
 		return -EAGAIN;
 	}

 	return 0;
 }

 static void __exit esp6_fini(void)
 {
 	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
 		pr_info("%s: can't remove protocol\n", __func__);
 	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
 		pr_info("%s: can't remove xfrm type\n", __func__);
 }

 module_init(esp6_init);
 module_exit(esp6_fini);

 MODULE_LICENSE("GPL");
 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
	/*
	* 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, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	* 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>

	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_givcrypt_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_givcrypt_request *esp_tmp_givreq(
	struct crypto_aead aead, u8 iv)
	{
	struct aead_givcrypt_request *req;

	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
	crypto_tfm_ctx_alignment());
	aead_givcrypt_set_tfm(req, aead);
	return req;
	}

	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 inline struct scatterlist *esp_givreq_sg(
	struct crypto_aead aead, struct aead_givcrypt_request req)
	{
	return (void *)ALIGN((unsigned long)(req + 1) +
	crypto_aead_reqsize(aead),
	__alignof__(struct scatterlist));
	}

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

	kfree(ESP_SKB_CB(skb)->tmp);
	xfrm_output_resume(skb, err);
	}

	static int esp6_output(struct xfrm_state x, struct sk_buff skb)
	{
	int err;
	struct ip_esp_hdr *esph;
	struct crypto_aead *aead;
	struct aead_givcrypt_request *req;
	struct scatterlist *sg;
	struct scatterlist *asg;
	struct sk_buff *trailer;
	void *tmp;
	int blksize;
	int clen;
	int alen;
	int plen;
	int tfclen;
	int nfrags;
	int assoclen;
	int sglists;
	int seqhilen;
	u8 *iv;
	u8 *tail;
	__be32 *seqhi;
	struct esp_data *esp = x->data;

	/* skb is pure payload to encrypt */
	aead = esp->aead;
	alen = crypto_aead_authsize(aead);

	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)
	tfclen = padto - skb->len;
	}
	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
	clen = ALIGN(skb->len + 2 + tfclen, blksize);
	if (esp->padlen)
	clen = ALIGN(clen, esp->padlen);
	plen = clen - skb->len - tfclen;

	err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
	if (err < 0)
	goto error;
	nfrags = err;

	assoclen = sizeof(*esph);
	sglists = 1;
	seqhilen = 0;

	if (x->props.flags & XFRM_STATE_ESN) {
	sglists += 2;
	seqhilen += sizeof(__be32);
	assoclen += seqhilen;
	}

	tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
	if (!tmp) {
	err = -ENOMEM;
	goto error;
	}

	seqhi = esp_tmp_seqhi(tmp);
	iv = esp_tmp_iv(aead, tmp, seqhilen);
	req = esp_tmp_givreq(aead, iv);
	asg = esp_givreq_sg(aead, req);
	sg = asg + sglists;

	/* Fill padding... */
	tail = skb_tail_pointer(trailer);
	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] = *skb_mac_header(skb);
	pskb_put(skb, trailer, clen - skb->len + alen);

	skb_push(skb, -skb_network_offset(skb));
	esph = ip_esp_hdr(skb);
	*skb_mac_header(skb) = IPPROTO_ESP;

	esph->spi = x->id.spi;
	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);

	sg_init_table(sg, nfrags);
	skb_to_sgvec(skb, sg,
	esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
	clen + alen);

	if ((x->props.flags & XFRM_STATE_ESN)) {
	sg_init_table(asg, 3);
	sg_set_buf(asg, &esph->spi, sizeof(__be32));
	*seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
	sg_set_buf(asg + 1, seqhi, seqhilen);
	sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
	} else
	sg_init_one(asg, esph, sizeof(*esph));

	aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
	aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
	aead_givcrypt_set_assoc(req, asg, assoclen);
	aead_givcrypt_set_giv(req, esph->enc_data,
	XFRM_SKB_CB(skb)->seq.output.low);

	ESP_SKB_CB(skb)->tmp = tmp;
	err = crypto_aead_givencrypt(req);
	if (err == -EINPROGRESS)
	goto error;

	if (err == -EBUSY)
	err = NET_XMIT_DROP;

	kfree(tmp);

	error:
	return err;
	}

	static int esp_input_done2(struct sk_buff *skb, int err)
	{
	struct xfrm_state *x = xfrm_input_state(skb);
	struct esp_data *esp = x->data;
	struct crypto_aead *aead = esp->aead;
	int alen = crypto_aead_authsize(aead);
	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
	int elen = skb->len - hlen;
	int hdr_len = skb_network_header_len(skb);
	int padlen;
	u8 nexthdr[2];

	kfree(ESP_SKB_CB(skb)->tmp);

	if (unlikely(err))
	goto out;

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

	err = -EINVAL;
	padlen = nexthdr[0];
	if (padlen + 2 + alen >= elen) {
	LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
	"padlen=%d, elen=%d\n", padlen + 2, elen - alen);
	goto out;
	}

	/* ... check padding bits here. Silly. :-) */

	pskb_trim(skb, skb->len - alen - padlen - 2);
	__skb_pull(skb, hlen);
	if (x->props.mode == XFRM_MODE_TUNNEL)
	skb_reset_transport_header(skb);
	else
	skb_set_transport_header(skb, -hdr_len);

	err = nexthdr[1];

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

	out:
	return err;
	}

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

	xfrm_input_resume(skb, esp_input_done2(skb, err));
	}

	static int esp6_input(struct xfrm_state x, struct sk_buff skb)
	{
	struct ip_esp_hdr *esph;
	struct esp_data *esp = x->data;
	struct crypto_aead *aead = esp->aead;
	struct aead_request *req;
	struct sk_buff *trailer;
	int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
	int nfrags;
	int assoclen;
	int sglists;
	int seqhilen;
	int ret = 0;
	void *tmp;
	__be32 *seqhi;
	u8 *iv;
	struct scatterlist *sg;
	struct scatterlist *asg;

	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
	ret = -EINVAL;
	goto out;
	}

	if (elen <= 0) {
	ret = -EINVAL;
	goto out;
	}

	if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
	ret = -EINVAL;
	goto out;
	}

	ret = -ENOMEM;

	assoclen = sizeof(*esph);
	sglists = 1;
	seqhilen = 0;

	if (x->props.flags & XFRM_STATE_ESN) {
	sglists += 2;
	seqhilen += sizeof(__be32);
	assoclen += seqhilen;
	}

	tmp = esp_alloc_tmp(aead, nfrags + sglists, 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);
	asg = esp_req_sg(aead, req);
	sg = asg + sglists;

	skb->ip_summed = CHECKSUM_NONE;

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

	/* Get ivec. This can be wrong, check against another impls. */
	iv = esph->enc_data;

	sg_init_table(sg, nfrags);
	skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);

	if ((x->props.flags & XFRM_STATE_ESN)) {
	sg_init_table(asg, 3);
	sg_set_buf(asg, &esph->spi, sizeof(__be32));
	*seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
	sg_set_buf(asg + 1, seqhi, seqhilen);
	sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
	} else
	sg_init_one(asg, esph, sizeof(*esph));

	aead_request_set_callback(req, 0, esp_input_done, skb);
	aead_request_set_crypt(req, sg, sg, elen, iv);
	aead_request_set_assoc(req, asg, assoclen);

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

	ret = esp_input_done2(skb, ret);

	out:
	return ret;
	}

	static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
	{
	struct esp_data *esp = x->data;
	u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
	u32 align = max_t(u32, blksize, esp->padlen);
	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(esp->aead) -
	net_adj) & ~(align - 1)) + net_adj - 2;
	}

	static void 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_DEST_UNREACH &&
	type != ICMPV6_PKT_TOOBIG &&
	type != NDISC_REDIRECT)
	return;

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

	if (type == NDISC_REDIRECT)
	ip6_redirect(skb, net, skb->dev->ifindex, 0);
	else
	ip6_update_pmtu(skb, net, info, 0, 0);
	xfrm_state_put(x);
	}

	static void esp6_destroy(struct xfrm_state *x)
	{
	struct esp_data *esp = x->data;

	if (!esp)
	return;

	crypto_free_aead(esp->aead);
	kfree(esp);
	}

	static int esp_init_aead(struct xfrm_state *x)
	{
	struct esp_data *esp = x->data;
	struct crypto_aead *aead;
	int err;

	aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
	err = PTR_ERR(aead);
	if (IS_ERR(aead))
	goto error;

	esp->aead = 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 esp_data *esp = x->data;
	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;

	err = -EINVAL;
	if (x->ealg == NULL)
	goto error;

	err = -ENAMETOOLONG;

	if ((x->props.flags & XFRM_STATE_ESN)) {
	if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
	"authencesn(%s,%s)",
	x->aalg ? x->aalg->alg_name : "digest_null",
	x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
	goto error;
	} else {
	if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
	"authenc(%s,%s)",
	x->aalg ? x->aalg->alg_name : "digest_null",
	x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
	goto error;
	}

	aead = crypto_alloc_aead(authenc_name, 0, 0);
	err = PTR_ERR(aead);
	if (IS_ERR(aead))
	goto error;

	esp->aead = 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)) {
	NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
	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 esp_data *esp;
	struct crypto_aead *aead;
	u32 align;
	int err;

	if (x->encap)
	return -EINVAL;

	esp = kzalloc(sizeof(*esp), GFP_KERNEL);
	if (esp == NULL)
	return -ENOMEM;

	x->data = esp;

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

	if (err)
	goto error;

	aead = esp->aead;

	esp->padlen = 0;

	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);
	if (esp->padlen)
	align = max_t(u32, align, esp->padlen);
	x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);

	error:
	return err;
	}

	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 const struct inet6_protocol esp6_protocol = {
	.handler = xfrm6_rcv,
	.err_handler = esp6_err,
	.flags = INET6_PROTO_NOPOLICY,
	};

	static int __init esp6_init(void)
	{
	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
	pr_info("%s: can't add xfrm type\n", __func__);
	return -EAGAIN;
	}
	if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
	pr_info("%s: can't add protocol\n", __func__);
	xfrm_unregister_type(&esp6_type, AF_INET6);
	return -EAGAIN;
	}

	return 0;
	}

	static void __exit esp6_fini(void)
	{
	if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
	pr_info("%s: can't remove protocol\n", __func__);
	if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
	pr_info("%s: can't remove xfrm type\n", __func__);
	}

	module_init(esp6_init);
	module_exit(esp6_fini);

	MODULE_LICENSE("GPL");
	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);