[linux-2.6-block.git] / net / ipv6 / esp6_offload.c

/*
 * IPV6 GSO/GRO offload support
 * Linux INET implementation
 *
 * Copyright (C) 2016 secunet Security Networks AG
 * Author: Steffen Klassert <steffen.klassert@secunet.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * ESP GRO support
 */

#include <linux/skbuff.h>
#include <linux/init.h>
#include <net/protocol.h>
#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/slab.h>
#include <linux/spinlock.h>
#include <net/ip6_route.h>
#include <net/ipv6.h>
#include <linux/icmpv6.h>

static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
{
	int off = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr;

	if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
		return offsetof(struct ipv6hdr, nexthdr);

	while (off < nhlen) {
		exthdr = (void *)ipv6_hdr + off;
		if (exthdr->nexthdr == NEXTHDR_ESP)
			return off;

		off += ipv6_optlen(exthdr);
	}

	return 0;
}

static struct sk_buff **esp6_gro_receive(struct sk_buff **head,
					 struct sk_buff *skb)
{
	int offset = skb_gro_offset(skb);
	struct xfrm_offload *xo;
	struct xfrm_state *x;
	__be32 seq;
	__be32 spi;
	int nhoff;
	int err;

	if (!pskb_pull(skb, offset))
		return NULL;

	if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
		goto out;

	xo = xfrm_offload(skb);
	if (!xo || !(xo->flags & CRYPTO_DONE)) {
		err = secpath_set(skb);
		if (err)
			goto out;

		if (skb->sp->len == XFRM_MAX_DEPTH)
			goto out;

		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
				      (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
				      spi, IPPROTO_ESP, AF_INET6);
		if (!x)
			goto out;

		skb->sp->xvec[skb->sp->len++] = x;
		skb->sp->olen++;

		xo = xfrm_offload(skb);
		if (!xo) {
			xfrm_state_put(x);
			goto out;
		}
	}

	xo->flags |= XFRM_GRO;

	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
	if (!nhoff)
		goto out;

	IP6CB(skb)->nhoff = nhoff;
	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
	XFRM_SPI_SKB_CB(skb)->seq = seq;

	/* We don't need to handle errors from xfrm_input, it does all
	 * the error handling and frees the resources on error. */
	xfrm_input(skb, IPPROTO_ESP, spi, -2);

	return ERR_PTR(-EINPROGRESS);
out:
	skb_push(skb, offset);
	NAPI_GRO_CB(skb)->same_flow = 0;
	NAPI_GRO_CB(skb)->flush = 1;

	return NULL;
}

static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ip_esp_hdr *esph;
	struct ipv6hdr *iph = ipv6_hdr(skb);
	struct xfrm_offload *xo = xfrm_offload(skb);
	int proto = iph->nexthdr;

	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);

	xo->proto = proto;
}

static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
				        netdev_features_t features)
{
	__u32 seq;
	int err = 0;
	struct sk_buff *skb2;
	struct xfrm_state *x;
	struct ip_esp_hdr *esph;
	struct crypto_aead *aead;
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	netdev_features_t esp_features = features;
	struct xfrm_offload *xo = xfrm_offload(skb);

	if (!xo)
		goto out;

	seq = xo->seq.low;

	x = skb->sp->xvec[skb->sp->len - 1];
	aead = x->data;
	esph = ip_esp_hdr(skb);

	if (esph->spi != x->id.spi)
		goto out;

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

	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));

	skb->encap_hdr_csum = 1;

	if (!(features & NETIF_F_HW_ESP))
		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);

	segs = x->outer_mode->gso_segment(x, skb, esp_features);
	if (IS_ERR_OR_NULL(segs))
		goto out;

	__skb_pull(skb, skb->data - skb_mac_header(skb));

	skb2 = segs;
	do {
		struct sk_buff *nskb = skb2->next;

		xo = xfrm_offload(skb2);
		xo->flags |= XFRM_GSO_SEGMENT;
		xo->seq.low = seq;
		xo->seq.hi = xfrm_replay_seqhi(x, seq);

		if(!(features & NETIF_F_HW_ESP))
			xo->flags |= CRYPTO_FALLBACK;

		x->outer_mode->xmit(x, skb2);

		err = x->type_offload->xmit(x, skb2, esp_features);
		if (err) {
			kfree_skb_list(segs);
			return ERR_PTR(err);
		}

		if (!skb_is_gso(skb2))
			seq++;
		else
			seq += skb_shinfo(skb2)->gso_segs;

		skb_push(skb2, skb2->mac_len);
		skb2 = nskb;
	} while (skb2);

out:
	return segs;
}

static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
{
	struct crypto_aead *aead = x->data;
	struct xfrm_offload *xo = xfrm_offload(skb);

	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
		return -EINVAL;

	if (!(xo->flags & CRYPTO_DONE))
		skb->ip_summed = CHECKSUM_NONE;

	return esp6_input_done2(skb, 0);
}

static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
{
	int err;
	int alen;
	int blksize;
	struct xfrm_offload *xo;
	struct ip_esp_hdr *esph;
	struct crypto_aead *aead;
	struct esp_info esp;
	bool hw_offload = true;

	esp.inplace = true;

	xo = xfrm_offload(skb);

	if (!xo)
		return -EINVAL;

	if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle ||
	    (x->xso.dev != skb->dev)) {
		xo->flags |= CRYPTO_FALLBACK;
		hw_offload = false;
	}

	esp.proto = xo->proto;

	/* skb is pure payload to encrypt */

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

	esp.tfclen = 0;
	/* XXX: Add support for tfc padding here. */

	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;

	if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
		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;

	skb_push(skb, -skb_network_offset(skb));

	if (xo->flags & XFRM_GSO_SEGMENT) {
		esph->seq_no = htonl(xo->seq.low);
	} else {
		int len;

		len = skb->len - sizeof(struct ipv6hdr);
		if (len > IPV6_MAXPLEN)
			len = 0;

		ipv6_hdr(skb)->payload_len = htons(len);
	}

	if (hw_offload)
		return 0;

	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));

	err = esp6_output_tail(x, skb, &esp);
	if (err)
		return err;

	secpath_reset(skb);

	return 0;
}

static const struct net_offload esp6_offload = {
	.callbacks = {
		.gro_receive = esp6_gro_receive,
		.gso_segment = esp6_gso_segment,
	},
};

static const struct xfrm_type_offload esp6_type_offload = {
	.description	= "ESP6 OFFLOAD",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_ESP,
	.input_tail	= esp6_input_tail,
	.xmit		= esp6_xmit,
	.encap		= esp6_gso_encap,
};

static int __init esp6_offload_init(void)
{
	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
		pr_info("%s: can't add xfrm type offload\n", __func__);
		return -EAGAIN;
	}

	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
}

static void __exit esp6_offload_exit(void)
{
	if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0)
		pr_info("%s: can't remove xfrm type offload\n", __func__);

	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
}

module_init(esp6_offload_init);
module_exit(esp6_offload_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
Commit	Line	Data
7785bba2 SK	1	/*
	2	* IPV6 GSO/GRO offload support
	3	* Linux INET implementation
	4	*
	5	* Copyright (C) 2016 secunet Security Networks AG
	6	* Author: Steffen Klassert <steffen.klassert@secunet.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms and conditions of the GNU General Public License,
	10	* version 2, as published by the Free Software Foundation.
	11	*
	12	* ESP GRO support
	13	*/
	14
	15	#include <linux/skbuff.h>
	16	#include <linux/init.h>
	17	#include <net/protocol.h>
	18	#include <crypto/aead.h>
	19	#include <crypto/authenc.h>
	20	#include <linux/err.h>
	21	#include <linux/module.h>
	22	#include <net/ip.h>
	23	#include <net/xfrm.h>
	24	#include <net/esp.h>
	25	#include <linux/scatterlist.h>
	26	#include <linux/kernel.h>
	27	#include <linux/slab.h>
	28	#include <linux/spinlock.h>
	29	#include <net/ip6_route.h>
	30	#include <net/ipv6.h>
	31	#include <linux/icmpv6.h>
	32
ca3a1b85 YK	33	static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
	34	{
	35	int off = sizeof(struct ipv6hdr);
	36	struct ipv6_opt_hdr *exthdr;
	37
	38	if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
	39	return offsetof(struct ipv6hdr, nexthdr);
	40
	41	while (off < nhlen) {
	42	exthdr = (void *)ipv6_hdr + off;
	43	if (exthdr->nexthdr == NEXTHDR_ESP)
	44	return off;
	45
	46	off += ipv6_optlen(exthdr);
	47	}
	48
	49	return 0;
	50	}
	51
7785bba2 SK	52	static struct sk_buff esp6_gro_receive(struct sk_buff head,
	53	struct sk_buff *skb)
	54	{
	55	int offset = skb_gro_offset(skb);
	56	struct xfrm_offload *xo;
	57	struct xfrm_state *x;
	58	__be32 seq;
	59	__be32 spi;
ca3a1b85	60	int nhoff;
7785bba2 SK	61	int err;
7785bba2 SK	62
374d1b5a SK	63	if (!pskb_pull(skb, offset))
374d1b5a SK	64	return NULL;
7785bba2 SK	65
	66	if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
	67	goto out;
	68
bcd1f8a4 SK	69	xo = xfrm_offload(skb);
	70	if (!xo \|\| !(xo->flags & CRYPTO_DONE)) {
	71	err = secpath_set(skb);
	72	if (err)
	73	goto out;
7785bba2	74
bcd1f8a4 SK	75	if (skb->sp->len == XFRM_MAX_DEPTH)
bcd1f8a4 SK	76	goto out;
7785bba2	77
bcd1f8a4 SK	78	x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
	79	(xfrm_address_t *)&ipv6_hdr(skb)->daddr,
	80	spi, IPPROTO_ESP, AF_INET6);
	81	if (!x)
	82	goto out;
7785bba2	83
bcd1f8a4 SK	84	skb->sp->xvec[skb->sp->len++] = x;
bcd1f8a4 SK	85	skb->sp->olen++;
7785bba2	86
bcd1f8a4 SK	87	xo = xfrm_offload(skb);
	88	if (!xo) {
	89	xfrm_state_put(x);
	90	goto out;
	91	}
7785bba2	92	}
bcd1f8a4	93
7785bba2 SK	94	xo->flags \|= XFRM_GRO;
7785bba2 SK	95
ca3a1b85 YK	96	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
	97	if (!nhoff)
	98	goto out;
	99
	100	IP6CB(skb)->nhoff = nhoff;
7785bba2 SK	101	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	102	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
	103	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
	104	XFRM_SPI_SKB_CB(skb)->seq = seq;
	105
	106	/* We don't need to handle errors from xfrm_input, it does all
	107	* the error handling and frees the resources on error. */
	108	xfrm_input(skb, IPPROTO_ESP, spi, -2);
	109
	110	return ERR_PTR(-EINPROGRESS);
	111	out:
	112	skb_push(skb, offset);
	113	NAPI_GRO_CB(skb)->same_flow = 0;
	114	NAPI_GRO_CB(skb)->flush = 1;
	115
	116	return NULL;
	117	}
	118
7862b405 SK	119	static void esp6_gso_encap(struct xfrm_state x, struct sk_buff skb)
	120	{
	121	struct ip_esp_hdr *esph;
	122	struct ipv6hdr *iph = ipv6_hdr(skb);
	123	struct xfrm_offload *xo = xfrm_offload(skb);
	124	int proto = iph->nexthdr;
	125
	126	skb_push(skb, -skb_network_offset(skb));
	127	esph = ip_esp_hdr(skb);
	128	*skb_mac_header(skb) = IPPROTO_ESP;
	129
	130	esph->spi = x->id.spi;
	131	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
	132
	133	xo->proto = proto;
	134	}
	135
	136	static struct sk_buff esp6_gso_segment(struct sk_buff skb,
	137	netdev_features_t features)
	138	{
	139	__u32 seq;
	140	int err = 0;
	141	struct sk_buff *skb2;
	142	struct xfrm_state *x;
	143	struct ip_esp_hdr *esph;
	144	struct crypto_aead *aead;
	145	struct sk_buff *segs = ERR_PTR(-EINVAL);
	146	netdev_features_t esp_features = features;
	147	struct xfrm_offload *xo = xfrm_offload(skb);
	148
ffa6f571	149	if (!xo)
7862b405 SK	150	goto out;
	151
	152	seq = xo->seq.low;
	153
	154	x = skb->sp->xvec[skb->sp->len - 1];
	155	aead = x->data;
	156	esph = ip_esp_hdr(skb);
	157
	158	if (esph->spi != x->id.spi)
	159	goto out;
	160
	161	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
	162	goto out;
	163
	164	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
	165
	166	skb->encap_hdr_csum = 1;
	167
	168	if (!(features & NETIF_F_HW_ESP))
	169	esp_features = features & ~(NETIF_F_SG \| NETIF_F_CSUM_MASK);
	170
	171	segs = x->outer_mode->gso_segment(x, skb, esp_features);
	172	if (IS_ERR_OR_NULL(segs))
	173	goto out;
	174
	175	__skb_pull(skb, skb->data - skb_mac_header(skb));
	176
	177	skb2 = segs;
	178	do {
	179	struct sk_buff *nskb = skb2->next;
	180
	181	xo = xfrm_offload(skb2);
	182	xo->flags \|= XFRM_GSO_SEGMENT;
	183	xo->seq.low = seq;
	184	xo->seq.hi = xfrm_replay_seqhi(x, seq);
	185
	186	if(!(features & NETIF_F_HW_ESP))
	187	xo->flags \|= CRYPTO_FALLBACK;
	188
	189	x->outer_mode->xmit(x, skb2);
	190
	191	err = x->type_offload->xmit(x, skb2, esp_features);
	192	if (err) {
	193	kfree_skb_list(segs);
	194	return ERR_PTR(err);
	195	}
	196
	197	if (!skb_is_gso(skb2))
	198	seq++;
	199	else
	200	seq += skb_shinfo(skb2)->gso_segs;
	201
	202	skb_push(skb2, skb2->mac_len);
	203	skb2 = nskb;
	204	} while (skb2);
	205
	206	out:
	207	return segs;
	208	}
	209
383d0350 SK	210	static int esp6_input_tail(struct xfrm_state x, struct sk_buff skb)
	211	{
	212	struct crypto_aead *aead = x->data;
e51a6472	213	struct xfrm_offload *xo = xfrm_offload(skb);
383d0350 SK	214
	215	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
	216	return -EINVAL;
	217
e51a6472 IT	218	if (!(xo->flags & CRYPTO_DONE))
e51a6472 IT	219	skb->ip_summed = CHECKSUM_NONE;
383d0350 SK	220
	221	return esp6_input_done2(skb, 0);
	222	}
	223
	224	static int esp6_xmit(struct xfrm_state x, struct sk_buff skb, netdev_features_t features)
	225	{
	226	int err;
	227	int alen;
	228	int blksize;
	229	struct xfrm_offload *xo;
	230	struct ip_esp_hdr *esph;
	231	struct crypto_aead *aead;
	232	struct esp_info esp;
	233	bool hw_offload = true;
	234
	235	esp.inplace = true;
	236
	237	xo = xfrm_offload(skb);
	238
	239	if (!xo)
	240	return -EINVAL;
	241
8f92e03e IT	242	if (!(features & NETIF_F_HW_ESP) \|\| !x->xso.offload_handle \|\|
8f92e03e IT	243	(x->xso.dev != skb->dev)) {
383d0350	244	xo->flags \|= CRYPTO_FALLBACK;
8f92e03e	245	hw_offload = false;
383d0350 SK	246	}
	247
	248	esp.proto = xo->proto;
	249
	250	/* skb is pure payload to encrypt */
	251
	252	aead = x->data;
	253	alen = crypto_aead_authsize(aead);
	254
	255	esp.tfclen = 0;
	256	/* XXX: Add support for tfc padding here. */
	257
	258	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
	259	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
	260	esp.plen = esp.clen - skb->len - esp.tfclen;
	261	esp.tailen = esp.tfclen + esp.plen + alen;
	262
	263	if (!hw_offload \|\| (hw_offload && !skb_is_gso(skb))) {
	264	esp.nfrags = esp6_output_head(x, skb, &esp);
	265	if (esp.nfrags < 0)
	266	return esp.nfrags;
	267	}
	268
	269	esph = ip_esp_hdr(skb);
	270	esph->spi = x->id.spi;
	271
	272	skb_push(skb, -skb_network_offset(skb));
	273
	274	if (xo->flags & XFRM_GSO_SEGMENT) {
	275	esph->seq_no = htonl(xo->seq.low);
	276	} else {
	277	int len;
	278
	279	len = skb->len - sizeof(struct ipv6hdr);
	280	if (len > IPV6_MAXPLEN)
	281	len = 0;
	282
	283	ipv6_hdr(skb)->payload_len = htons(len);
	284	}
	285
8f92e03e	286	if (hw_offload)
383d0350 SK	287	return 0;
	288
	289	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
	290
	291	err = esp6_output_tail(x, skb, &esp);
4ff0308f	292	if (err)
383d0350 SK	293	return err;
	294
	295	secpath_reset(skb);
	296
	297	return 0;
	298	}
	299
7785bba2 SK	300	static const struct net_offload esp6_offload = {
	301	.callbacks = {
	302	.gro_receive = esp6_gro_receive,
7862b405	303	.gso_segment = esp6_gso_segment,
7785bba2 SK	304	},
	305	};
	306
383d0350 SK	307	static const struct xfrm_type_offload esp6_type_offload = {
	308	.description = "ESP6 OFFLOAD",
	309	.owner = THIS_MODULE,
	310	.proto = IPPROTO_ESP,
	311	.input_tail = esp6_input_tail,
	312	.xmit = esp6_xmit,
7862b405	313	.encap = esp6_gso_encap,
383d0350 SK	314	};
383d0350 SK	315
7785bba2 SK	316	static int __init esp6_offload_init(void)
7785bba2 SK	317	{
383d0350 SK	318	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
	319	pr_info("%s: can't add xfrm type offload\n", __func__);
	320	return -EAGAIN;
	321	}
	322
7785bba2 SK	323	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
	324	}
	325
	326	static void __exit esp6_offload_exit(void)
	327	{
383d0350 SK	328	if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0)
	329	pr_info("%s: can't remove xfrm type offload\n", __func__);
	330
7785bba2 SK	331	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
	332	}
	333
	334	module_init(esp6_offload_init);
	335	module_exit(esp6_offload_exit);
	336	MODULE_LICENSE("GPL");
	337	MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
ffdb5211	338	MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);