net/ipv4/esp4.c - kernel/msm-4.9 - Gitiles

 #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/rtnetlink.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/in6.h>
 #include <net/icmp.h>
 #include <net/protocol.h>
 #include <net/udp.h>

 struct esp_skb_cb {
 	struct xfrm_skb_cb xfrm;
 	void *tmp;
 };

 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))

 /*
  * Allocate an AEAD request structure with extra space for SG and IV.
  *
  * For alignment considerations the IV is placed at the front, followed
  * by 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)
 {
 	unsigned int len;

 	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 u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
 {
 	return crypto_aead_ivsize(aead) ?
 	       PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
 }

 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 esp_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 esp_data *esp;
 	struct sk_buff *trailer;
 	void *tmp;
 	u8 *iv;
 	u8 *tail;
 	int blksize;
 	int clen;
 	int alen;
 	int nfrags;

 	/* skb is pure payload to encrypt */

 	err = -ENOMEM;

 	/* Round to block size */
 	clen = skb->len;

 	esp = x->data;
 	aead = esp->aead;
 	alen = crypto_aead_authsize(aead);

 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
 	clen = ALIGN(clen + 2, blksize);
 	if (esp->padlen)
 		clen = ALIGN(clen, esp->padlen);

 	if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
 		goto error;
 	nfrags = err;

 	tmp = esp_alloc_tmp(aead, nfrags + 1);
 	if (!tmp)
 		goto error;

 	iv = esp_tmp_iv(aead, tmp);
 	req = esp_tmp_givreq(aead, iv);
 	asg = esp_givreq_sg(aead, req);
 	sg = asg + 1;

 	/* Fill padding... */
 	tail = skb_tail_pointer(trailer);
 	do {
 		int i;
 		for (i=0; i<clen-skb->len - 2; i++)
 			tail[i] = i + 1;
 	} while (0);
 	tail[clen - skb->len - 2] = (clen - skb->len) - 2;
 	tail[clen - skb->len - 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;

 	/* this is non-NULL only with UDP Encapsulation */
 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;
 		struct udphdr *uh;
 		__be32 *udpdata32;
 		__be16 sport, dport;
 		int encap_type;

 		spin_lock_bh(&x->lock);
 		sport = encap->encap_sport;
 		dport = encap->encap_dport;
 		encap_type = encap->encap_type;
 		spin_unlock_bh(&x->lock);

 		uh = (struct udphdr *)esph;
 		uh->source = sport;
 		uh->dest = dport;
 		uh->len = htons(skb->len - skb_transport_offset(skb));
 		uh->check = 0;

 		switch (encap_type) {
 		default:
 		case UDP_ENCAP_ESPINUDP:
 			esph = (struct ip_esp_hdr *)(uh + 1);
 			break;
 		case UDP_ENCAP_ESPINUDP_NON_IKE:
 			udpdata32 = (__be32 *)(uh + 1);
 			udpdata32[0] = udpdata32[1] = 0;
 			esph = (struct ip_esp_hdr *)(udpdata32 + 2);
 			break;
 		}

 		*skb_mac_header(skb) = IPPROTO_UDP;
 	}

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

 	sg_init_table(sg, nfrags);
 	skb_to_sgvec(skb, sg,
 		     esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
 		     clen + alen);
 	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, sizeof(*esph));
 	aead_givcrypt_set_giv(req, esph->enc_data,
 			      XFRM_SKB_CB(skb)->seq.output);

 	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 iphdr *iph;
 	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 ihl;
 	u8 nexthdr[2];
 	int padlen;

 	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)
 		goto out;

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

 	iph = ip_hdr(skb);
 	ihl = iph->ihl * 4;

 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;
 		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);

 		/*
 		 * 1) if the NAT-T peer's IP or port changed then
 		 *    advertize the change to the keying daemon.
 		 *    This is an inbound SA, so just compare
 		 *    SRC ports.
 		 */
 		if (iph->saddr != x->props.saddr.a4 ||
 		    uh->source != encap->encap_sport) {
 			xfrm_address_t ipaddr;

 			ipaddr.a4 = iph->saddr;
 			km_new_mapping(x, &ipaddr, uh->source);

 			/* XXX: perhaps add an extra
 			 * policy check here, to see
 			 * if we should allow or
 			 * reject a packet from a
 			 * different source
 			 * address/port.
 			 */
 		}

 		/*
 		 * 2) ignore UDP/TCP checksums in case
 		 *    of NAT-T in Transport Mode, or
 		 *    perform other post-processing fixes
 		 *    as per draft-ietf-ipsec-udp-encaps-06,
 		 *    section 3.1.2
 		 */
 		if (x->props.mode == XFRM_MODE_TRANSPORT)
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
 	}

 	pskb_trim(skb, skb->len - alen - padlen - 2);
 	__skb_pull(skb, hlen);
 	skb_set_transport_header(skb, -ihl);

 	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));
 }

 /*
  * Note: detecting truncated vs. non-truncated authentication data is very
  * expensive, so we only support truncated data, which is the recommended
  * and common case.
  */
 static int esp_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;
 	void *tmp;
 	u8 *iv;
 	struct scatterlist *sg;
 	struct scatterlist *asg;
 	int err = -EINVAL;

 	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
 		goto out;

 	if (elen <= 0)
 		goto out;

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

 	err = -ENOMEM;
 	tmp = esp_alloc_tmp(aead, nfrags + 1);
 	if (!tmp)
 		goto out;

 	ESP_SKB_CB(skb)->tmp = tmp;
 	iv = esp_tmp_iv(aead, tmp);
 	req = esp_tmp_req(aead, iv);
 	asg = esp_req_sg(aead, req);
 	sg = asg + 1;

 	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);
 	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, sizeof(*esph));

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

 	err = esp_input_done2(skb, err);

 out:
 	return err;
 }

 static u32 esp4_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);
 	u32 rem;

 	mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
 	rem = mtu & (align - 1);
 	mtu &= ~(align - 1);

 	switch (x->props.mode) {
 	case XFRM_MODE_TUNNEL:
 		break;
 	default:
 	case XFRM_MODE_TRANSPORT:
 		/* The worst case */
 		mtu -= blksize - 4;
 		mtu += min_t(u32, blksize - 4, rem);
 		break;
 	case XFRM_MODE_BEET:
 		/* The worst case. */
 		mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
 		break;
 	}

 	return mtu - 2;
 }

 static void esp4_err(struct sk_buff *skb, u32 info)
 {
 	struct iphdr *iph = (struct iphdr *)skb->data;
 	struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 	struct xfrm_state *x;

 	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
 	    icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 		return;

 	x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
 	if (!x)
 		return;
 	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
 		 ntohl(esph->spi), ntohl(iph->daddr));
 	xfrm_state_put(x);
 }

 static void esp_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 (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, aalg_desc->uinfo.auth.icv_truncbits / 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 esp_init_state(struct xfrm_state *x)
 {
 	struct esp_data *esp;
 	struct crypto_aead *aead;
 	u32 align;
 	int err;

 	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);
 	if (x->props.mode == XFRM_MODE_TUNNEL)
 		x->props.header_len += sizeof(struct iphdr);
 	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
 		x->props.header_len += IPV4_BEET_PHMAXLEN;
 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;

 		switch (encap->encap_type) {
 		default:
 			goto error;
 		case UDP_ENCAP_ESPINUDP:
 			x->props.header_len += sizeof(struct udphdr);
 			break;
 		case UDP_ENCAP_ESPINUDP_NON_IKE:
 			x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
 			break;
 		}
 	}

 	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 esp_type =
 {
 	.description	= "ESP4",
 	.owner		= THIS_MODULE,
 	.proto	     	= IPPROTO_ESP,
 	.flags		= XFRM_TYPE_REPLAY_PROT,
 	.init_state	= esp_init_state,
 	.destructor	= esp_destroy,
 	.get_mtu	= esp4_get_mtu,
 	.input		= esp_input,
 	.output		= esp_output
 };

 static struct net_protocol esp4_protocol = {
 	.handler	=	xfrm4_rcv,
 	.err_handler	=	esp4_err,
 	.no_policy	=	1,
 };

 static int __init esp4_init(void)
 {
 	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
 		printk(KERN_INFO "ip esp init: can't add xfrm type\n");
 		return -EAGAIN;
 	}
 	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
 		printk(KERN_INFO "ip esp init: can't add protocol\n");
 		xfrm_unregister_type(&esp_type, AF_INET);
 		return -EAGAIN;
 	}
 	return 0;
 }

 static void __exit esp4_fini(void)
 {
 	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
 		printk(KERN_INFO "ip esp close: can't remove protocol\n");
 	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
 		printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
 }

 module_init(esp4_init);
 module_exit(esp4_fini);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
	#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/rtnetlink.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>
	#include <linux/in6.h>
	#include <net/icmp.h>
	#include <net/protocol.h>
	#include <net/udp.h>

	struct esp_skb_cb {
	struct xfrm_skb_cb xfrm;
	void *tmp;
	};

	#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))

	/*
	* Allocate an AEAD request structure with extra space for SG and IV.
	*
	* For alignment considerations the IV is placed at the front, followed
	* by 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)
	{
	unsigned int len;

	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 u8 esp_tmp_iv(struct crypto_aead aead, void *tmp)
	{
	return crypto_aead_ivsize(aead) ?
	PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
	}

	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 esp_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 esp_data *esp;
	struct sk_buff *trailer;
	void *tmp;
	u8 *iv;
	u8 *tail;
	int blksize;
	int clen;
	int alen;
	int nfrags;

	/* skb is pure payload to encrypt */

	err = -ENOMEM;

	/* Round to block size */
	clen = skb->len;

	esp = x->data;
	aead = esp->aead;
	alen = crypto_aead_authsize(aead);

	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
	clen = ALIGN(clen + 2, blksize);
	if (esp->padlen)
	clen = ALIGN(clen, esp->padlen);

	if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
	goto error;
	nfrags = err;

	tmp = esp_alloc_tmp(aead, nfrags + 1);
	if (!tmp)
	goto error;

	iv = esp_tmp_iv(aead, tmp);
	req = esp_tmp_givreq(aead, iv);
	asg = esp_givreq_sg(aead, req);
	sg = asg + 1;

	/* Fill padding... */
	tail = skb_tail_pointer(trailer);
	do {
	int i;
	for (i=0; i<clen-skb->len - 2; i++)
	tail[i] = i + 1;
	} while (0);
	tail[clen - skb->len - 2] = (clen - skb->len) - 2;
	tail[clen - skb->len - 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;

	/* this is non-NULL only with UDP Encapsulation */
	if (x->encap) {
	struct xfrm_encap_tmpl *encap = x->encap;
	struct udphdr *uh;
	__be32 *udpdata32;
	__be16 sport, dport;
	int encap_type;

	spin_lock_bh(&x->lock);
	sport = encap->encap_sport;
	dport = encap->encap_dport;
	encap_type = encap->encap_type;
	spin_unlock_bh(&x->lock);

	uh = (struct udphdr *)esph;
	uh->source = sport;
	uh->dest = dport;
	uh->len = htons(skb->len - skb_transport_offset(skb));
	uh->check = 0;

	switch (encap_type) {
	default:
	case UDP_ENCAP_ESPINUDP:
	esph = (struct ip_esp_hdr *)(uh + 1);
	break;
	case UDP_ENCAP_ESPINUDP_NON_IKE:
	udpdata32 = (__be32 *)(uh + 1);
	udpdata32[0] = udpdata32[1] = 0;
	esph = (struct ip_esp_hdr *)(udpdata32 + 2);
	break;
	}

	*skb_mac_header(skb) = IPPROTO_UDP;
	}

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

	sg_init_table(sg, nfrags);
	skb_to_sgvec(skb, sg,
	esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
	clen + alen);
	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, sizeof(*esph));
	aead_givcrypt_set_giv(req, esph->enc_data,
	XFRM_SKB_CB(skb)->seq.output);

	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 iphdr *iph;
	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 ihl;
	u8 nexthdr[2];
	int padlen;

	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)
	goto out;

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

	iph = ip_hdr(skb);
	ihl = iph->ihl * 4;

	if (x->encap) {
	struct xfrm_encap_tmpl *encap = x->encap;
	struct udphdr uh = (void )(skb_network_header(skb) + ihl);

	/*
	* 1) if the NAT-T peer's IP or port changed then
	* advertize the change to the keying daemon.
	* This is an inbound SA, so just compare
	* SRC ports.
	*/
	if (iph->saddr != x->props.saddr.a4 \|\|
	uh->source != encap->encap_sport) {
	xfrm_address_t ipaddr;

	ipaddr.a4 = iph->saddr;
	km_new_mapping(x, &ipaddr, uh->source);

	/* XXX: perhaps add an extra
	* policy check here, to see
	* if we should allow or
	* reject a packet from a
	* different source
	* address/port.
	*/
	}

	/*
	* 2) ignore UDP/TCP checksums in case
	* of NAT-T in Transport Mode, or
	* perform other post-processing fixes
	* as per draft-ietf-ipsec-udp-encaps-06,
	* section 3.1.2
	*/
	if (x->props.mode == XFRM_MODE_TRANSPORT)
	skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	pskb_trim(skb, skb->len - alen - padlen - 2);
	__skb_pull(skb, hlen);
	skb_set_transport_header(skb, -ihl);

	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));
	}

	/*
	* Note: detecting truncated vs. non-truncated authentication data is very
	* expensive, so we only support truncated data, which is the recommended
	* and common case.
	*/
	static int esp_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;
	void *tmp;
	u8 *iv;
	struct scatterlist *sg;
	struct scatterlist *asg;
	int err = -EINVAL;

	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
	goto out;

	if (elen <= 0)
	goto out;

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

	err = -ENOMEM;
	tmp = esp_alloc_tmp(aead, nfrags + 1);
	if (!tmp)
	goto out;

	ESP_SKB_CB(skb)->tmp = tmp;
	iv = esp_tmp_iv(aead, tmp);
	req = esp_tmp_req(aead, iv);
	asg = esp_req_sg(aead, req);
	sg = asg + 1;

	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);
	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, sizeof(*esph));

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

	err = esp_input_done2(skb, err);

	out:
	return err;
	}

	static u32 esp4_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);
	u32 rem;

	mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
	rem = mtu & (align - 1);
	mtu &= ~(align - 1);

	switch (x->props.mode) {
	case XFRM_MODE_TUNNEL:
	break;
	default:
	case XFRM_MODE_TRANSPORT:
	/* The worst case */
	mtu -= blksize - 4;
	mtu += min_t(u32, blksize - 4, rem);
	break;
	case XFRM_MODE_BEET:
	/* The worst case. */
	mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
	break;
	}

	return mtu - 2;
	}

	static void esp4_err(struct sk_buff *skb, u32 info)
	{
	struct iphdr iph = (struct iphdr )skb->data;
	struct ip_esp_hdr esph = (struct ip_esp_hdr )(skb->data+(iph->ihl<<2));
	struct xfrm_state *x;

	if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH \|\|
	icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
	return;

	x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
	if (!x)
	return;
	NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
	ntohl(esph->spi), ntohl(iph->daddr));
	xfrm_state_put(x);
	}

	static void esp_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 (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, aalg_desc->uinfo.auth.icv_truncbits / 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 esp_init_state(struct xfrm_state *x)
	{
	struct esp_data *esp;
	struct crypto_aead *aead;
	u32 align;
	int err;

	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);
	if (x->props.mode == XFRM_MODE_TUNNEL)
	x->props.header_len += sizeof(struct iphdr);
	else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
	x->props.header_len += IPV4_BEET_PHMAXLEN;
	if (x->encap) {
	struct xfrm_encap_tmpl *encap = x->encap;

	switch (encap->encap_type) {
	default:
	goto error;
	case UDP_ENCAP_ESPINUDP:
	x->props.header_len += sizeof(struct udphdr);
	break;
	case UDP_ENCAP_ESPINUDP_NON_IKE:
	x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
	break;
	}
	}

	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 esp_type =
	{
	.description = "ESP4",
	.owner = THIS_MODULE,
	.proto = IPPROTO_ESP,
	.flags = XFRM_TYPE_REPLAY_PROT,
	.init_state = esp_init_state,
	.destructor = esp_destroy,
	.get_mtu = esp4_get_mtu,
	.input = esp_input,
	.output = esp_output
	};

	static struct net_protocol esp4_protocol = {
	.handler = xfrm4_rcv,
	.err_handler = esp4_err,
	.no_policy = 1,
	};

	static int __init esp4_init(void)
	{
	if (xfrm_register_type(&esp_type, AF_INET) < 0) {
	printk(KERN_INFO "ip esp init: can't add xfrm type\n");
	return -EAGAIN;
	}
	if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
	printk(KERN_INFO "ip esp init: can't add protocol\n");
	xfrm_unregister_type(&esp_type, AF_INET);
	return -EAGAIN;
	}
	return 0;
	}

	static void __exit esp4_fini(void)
	{
	if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
	printk(KERN_INFO "ip esp close: can't remove protocol\n");
	if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
	printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
	}

	module_init(esp4_init);
	module_exit(esp4_fini);
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);