1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * IPV4 GSO/GRO offload support
  4 * Linux INET implementation
  5 *
  6 * Copyright (C) 2016 secunet Security Networks AG
  7 * Author: Steffen Klassert <steffen.klassert@secunet.com>
  8 *
  9 * ESP GRO support
 10 */
 11
 12#include <linux/skbuff.h>
 13#include <linux/init.h>
 14#include <net/protocol.h>
 15#include <crypto/aead.h>
 16#include <crypto/authenc.h>
 17#include <linux/err.h>
 18#include <linux/module.h>
 19#include <net/ip.h>
 20#include <net/xfrm.h>
 21#include <net/esp.h>
 22#include <linux/scatterlist.h>
 23#include <linux/kernel.h>
 24#include <linux/slab.h>
 25#include <linux/spinlock.h>
 26#include <net/udp.h>
 27
 28static struct sk_buff *esp4_gro_receive(struct list_head *head,
 29					struct sk_buff *skb)
 30{
 31	int offset = skb_gro_offset(skb);
 32	struct xfrm_offload *xo;
 33	struct xfrm_state *x;
 34	__be32 seq;
 35	__be32 spi;
 36	int err;
 37
 38	if (!pskb_pull(skb, offset))
 39		return NULL;
 40
 41	if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
 42		goto out;
 43
 44	xo = xfrm_offload(skb);
 45	if (!xo || !(xo->flags & CRYPTO_DONE)) {
 46		struct sec_path *sp = secpath_set(skb);
 47
 48		if (!sp)
 49			goto out;
 50
 51		if (sp->len == XFRM_MAX_DEPTH)
 52			goto out_reset;
 53
 54		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
 55				      (xfrm_address_t *)&ip_hdr(skb)->daddr,
 56				      spi, IPPROTO_ESP, AF_INET);
 57		if (!x)
 58			goto out_reset;
 59
 60		sp->xvec[sp->len++] = x;
 61		sp->olen++;
 62
 63		xo = xfrm_offload(skb);
 64		if (!xo) {
 65			xfrm_state_put(x);
 66			goto out_reset;
 67		}
 68	}
 69
 70	xo->flags |= XFRM_GRO;
 71
 72	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
 73	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
 74	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
 75	XFRM_SPI_SKB_CB(skb)->seq = seq;
 76
 77	/* We don't need to handle errors from xfrm_input, it does all
 78	 * the error handling and frees the resources on error. */
 79	xfrm_input(skb, IPPROTO_ESP, spi, -2);
 80
 81	return ERR_PTR(-EINPROGRESS);
 82out_reset:
 83	secpath_reset(skb);
 84out:
 85	skb_push(skb, offset);
 86	NAPI_GRO_CB(skb)->same_flow = 0;
 87	NAPI_GRO_CB(skb)->flush = 1;
 88
 89	return NULL;
 90}
 91
 92static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
 93{
 94	struct ip_esp_hdr *esph;
 95	struct iphdr *iph = ip_hdr(skb);
 96	struct xfrm_offload *xo = xfrm_offload(skb);
 97	int proto = iph->protocol;
 98
 99	skb_push(skb, -skb_network_offset(skb));
100	esph = ip_esp_hdr(skb);
101	*skb_mac_header(skb) = IPPROTO_ESP;
102
103	esph->spi = x->id.spi;
104	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
105
106	xo->proto = proto;
107}
108
109static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
110						struct sk_buff *skb,
111						netdev_features_t features)
112{
113	__skb_push(skb, skb->mac_len);
114	return skb_mac_gso_segment(skb, features);
115}
116
117static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
118						   struct sk_buff *skb,
119						   netdev_features_t features)
120{
121	const struct net_offload *ops;
122	struct sk_buff *segs = ERR_PTR(-EINVAL);
123	struct xfrm_offload *xo = xfrm_offload(skb);
124
125	skb->transport_header += x->props.header_len;
126	ops = rcu_dereference(inet_offloads[xo->proto]);
127	if (likely(ops && ops->callbacks.gso_segment))
128		segs = ops->callbacks.gso_segment(skb, features);
129
130	return segs;
131}
132
133static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
134						    struct sk_buff *skb,
135						    netdev_features_t features)
136{
137	switch (x->outer_mode.encap) {
138	case XFRM_MODE_TUNNEL:
139		return xfrm4_tunnel_gso_segment(x, skb, features);
140	case XFRM_MODE_TRANSPORT:
141		return xfrm4_transport_gso_segment(x, skb, features);
142	}
143
144	return ERR_PTR(-EOPNOTSUPP);
145}
146
147static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
148				        netdev_features_t features)
149{
150	struct xfrm_state *x;
151	struct ip_esp_hdr *esph;
152	struct crypto_aead *aead;
153	netdev_features_t esp_features = features;
154	struct xfrm_offload *xo = xfrm_offload(skb);
155	struct sec_path *sp;
156
157	if (!xo)
158		return ERR_PTR(-EINVAL);
159
160	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
161		return ERR_PTR(-EINVAL);
162
163	sp = skb_sec_path(skb);
164	x = sp->xvec[sp->len - 1];
165	aead = x->data;
166	esph = ip_esp_hdr(skb);
167
168	if (esph->spi != x->id.spi)
169		return ERR_PTR(-EINVAL);
170
171	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
172		return ERR_PTR(-EINVAL);
173
174	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
175
176	skb->encap_hdr_csum = 1;
177
178	if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
179	     !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
180		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
181	else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
182		 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
183		esp_features = features & ~NETIF_F_CSUM_MASK;
184
185	xo->flags |= XFRM_GSO_SEGMENT;
186
187	return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
188}
189
190static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
191{
192	struct crypto_aead *aead = x->data;
193	struct xfrm_offload *xo = xfrm_offload(skb);
194
195	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
196		return -EINVAL;
197
198	if (!(xo->flags & CRYPTO_DONE))
199		skb->ip_summed = CHECKSUM_NONE;
200
201	return esp_input_done2(skb, 0);
202}
203
204static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
205{
206	int err;
207	int alen;
208	int blksize;
209	struct xfrm_offload *xo;
210	struct ip_esp_hdr *esph;
211	struct crypto_aead *aead;
212	struct esp_info esp;
213	bool hw_offload = true;
214	__u32 seq;
215
216	esp.inplace = true;
217
218	xo = xfrm_offload(skb);
219
220	if (!xo)
221		return -EINVAL;
222
223	if ((!(features & NETIF_F_HW_ESP) &&
224	     !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
225	    x->xso.dev != skb->dev) {
226		xo->flags |= CRYPTO_FALLBACK;
227		hw_offload = false;
228	}
229
230	esp.proto = xo->proto;
231
232	/* skb is pure payload to encrypt */
233
234	aead = x->data;
235	alen = crypto_aead_authsize(aead);
236
237	esp.tfclen = 0;
238	/* XXX: Add support for tfc padding here. */
239
240	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
241	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
242	esp.plen = esp.clen - skb->len - esp.tfclen;
243	esp.tailen = esp.tfclen + esp.plen + alen;
244
245	esp.esph = ip_esp_hdr(skb);
246
247
248	if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
249		esp.nfrags = esp_output_head(x, skb, &esp);
250		if (esp.nfrags < 0)
251			return esp.nfrags;
252	}
253
254	seq = xo->seq.low;
255
256	esph = esp.esph;
257	esph->spi = x->id.spi;
258
259	skb_push(skb, -skb_network_offset(skb));
260
261	if (xo->flags & XFRM_GSO_SEGMENT) {
262		esph->seq_no = htonl(seq);
263
264		if (!skb_is_gso(skb))
265			xo->seq.low++;
266		else
267			xo->seq.low += skb_shinfo(skb)->gso_segs;
268	}
269
270	esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
271
272	ip_hdr(skb)->tot_len = htons(skb->len);
273	ip_send_check(ip_hdr(skb));
274
275	if (hw_offload)
276		return 0;
277
278	err = esp_output_tail(x, skb, &esp);
279	if (err)
280		return err;
281
282	secpath_reset(skb);
283
284	return 0;
285}
286
287static const struct net_offload esp4_offload = {
288	.callbacks = {
289		.gro_receive = esp4_gro_receive,
290		.gso_segment = esp4_gso_segment,
291	},
292};
293
294static const struct xfrm_type_offload esp_type_offload = {
295	.description	= "ESP4 OFFLOAD",
296	.owner		= THIS_MODULE,
297	.proto	     	= IPPROTO_ESP,
298	.input_tail	= esp_input_tail,
299	.xmit		= esp_xmit,
300	.encap		= esp4_gso_encap,
301};
302
303static int __init esp4_offload_init(void)
304{
305	if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
306		pr_info("%s: can't add xfrm type offload\n", __func__);
307		return -EAGAIN;
308	}
309
310	return inet_add_offload(&esp4_offload, IPPROTO_ESP);
311}
312
313static void __exit esp4_offload_exit(void)
314{
315	xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
316	inet_del_offload(&esp4_offload, IPPROTO_ESP);
317}
318
319module_init(esp4_offload_init);
320module_exit(esp4_offload_exit);
321MODULE_LICENSE("GPL");
322MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
323MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);