xref: /kernel/linux/linux-6.6/net/ipv6/esp6_offload.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * IPV6 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/gro.h>
20#include <net/gso.h>
21#include <net/ip.h>
22#include <net/xfrm.h>
23#include <net/esp.h>
24#include <linux/scatterlist.h>
25#include <linux/kernel.h>
26#include <linux/slab.h>
27#include <linux/spinlock.h>
28#include <net/ip6_route.h>
29#include <net/ipv6.h>
30#include <linux/icmpv6.h>
31
32static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
33{
34	int off = sizeof(struct ipv6hdr);
35	struct ipv6_opt_hdr *exthdr;
36
37	if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
38		return offsetof(struct ipv6hdr, nexthdr);
39
40	while (off < nhlen) {
41		exthdr = (void *)ipv6_hdr + off;
42		if (exthdr->nexthdr == NEXTHDR_ESP)
43			return off;
44
45		off += ipv6_optlen(exthdr);
46	}
47
48	return 0;
49}
50
51static struct sk_buff *esp6_gro_receive(struct list_head *head,
52					struct sk_buff *skb)
53{
54	int offset = skb_gro_offset(skb);
55	struct xfrm_offload *xo;
56	struct xfrm_state *x;
57	__be32 seq;
58	__be32 spi;
59	int nhoff;
60
61	if (!pskb_pull(skb, offset))
62		return NULL;
63
64	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
65		goto out;
66
67	xo = xfrm_offload(skb);
68	if (!xo || !(xo->flags & CRYPTO_DONE)) {
69		struct sec_path *sp = secpath_set(skb);
70
71		if (!sp)
72			goto out;
73
74		if (sp->len == XFRM_MAX_DEPTH)
75			goto out_reset;
76
77		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
78				      (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
79				      spi, IPPROTO_ESP, AF_INET6);
80		if (!x)
81			goto out_reset;
82
83		skb->mark = xfrm_smark_get(skb->mark, x);
84
85		sp->xvec[sp->len++] = x;
86		sp->olen++;
87
88		xo = xfrm_offload(skb);
89		if (!xo)
90			goto out_reset;
91	}
92
93	xo->flags |= XFRM_GRO;
94
95	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
96	if (!nhoff)
97		goto out;
98
99	IP6CB(skb)->nhoff = nhoff;
100	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
101	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
102	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
103	XFRM_SPI_SKB_CB(skb)->seq = seq;
104
105	/* We don't need to handle errors from xfrm_input, it does all
106	 * the error handling and frees the resources on error. */
107	xfrm_input(skb, IPPROTO_ESP, spi, -2);
108
109	return ERR_PTR(-EINPROGRESS);
110out_reset:
111	secpath_reset(skb);
112out:
113	skb_push(skb, offset);
114	NAPI_GRO_CB(skb)->same_flow = 0;
115	NAPI_GRO_CB(skb)->flush = 1;
116
117	return NULL;
118}
119
120static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
121{
122	struct ip_esp_hdr *esph;
123	struct ipv6hdr *iph = ipv6_hdr(skb);
124	struct xfrm_offload *xo = xfrm_offload(skb);
125	u8 proto = iph->nexthdr;
126
127	skb_push(skb, -skb_network_offset(skb));
128
129	if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
130		__be16 frag;
131
132		ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
133	}
134
135	esph = ip_esp_hdr(skb);
136	*skb_mac_header(skb) = IPPROTO_ESP;
137
138	esph->spi = x->id.spi;
139	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
140
141	xo->proto = proto;
142}
143
144static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
145						struct sk_buff *skb,
146						netdev_features_t features)
147{
148	__be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
149						      : htons(ETH_P_IPV6);
150
151	return skb_eth_gso_segment(skb, features, type);
152}
153
154static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
155						   struct sk_buff *skb,
156						   netdev_features_t features)
157{
158	const struct net_offload *ops;
159	struct sk_buff *segs = ERR_PTR(-EINVAL);
160	struct xfrm_offload *xo = xfrm_offload(skb);
161
162	skb->transport_header += x->props.header_len;
163	ops = rcu_dereference(inet6_offloads[xo->proto]);
164	if (likely(ops && ops->callbacks.gso_segment))
165		segs = ops->callbacks.gso_segment(skb, features);
166
167	return segs;
168}
169
170static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
171					      struct sk_buff *skb,
172					      netdev_features_t features)
173{
174	struct xfrm_offload *xo = xfrm_offload(skb);
175	struct sk_buff *segs = ERR_PTR(-EINVAL);
176	const struct net_offload *ops;
177	u8 proto = xo->proto;
178
179	skb->transport_header += x->props.header_len;
180
181	if (x->sel.family != AF_INET6) {
182		skb->transport_header -=
183			(sizeof(struct ipv6hdr) - sizeof(struct iphdr));
184
185		if (proto == IPPROTO_BEETPH) {
186			struct ip_beet_phdr *ph =
187				(struct ip_beet_phdr *)skb->data;
188
189			skb->transport_header += ph->hdrlen * 8;
190			proto = ph->nexthdr;
191		} else {
192			skb->transport_header -= IPV4_BEET_PHMAXLEN;
193		}
194
195		if (proto == IPPROTO_TCP)
196			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
197	} else {
198		__be16 frag;
199
200		skb->transport_header +=
201			ipv6_skip_exthdr(skb, 0, &proto, &frag);
202	}
203
204	if (proto == IPPROTO_IPIP)
205		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
206
207	__skb_pull(skb, skb_transport_offset(skb));
208	ops = rcu_dereference(inet6_offloads[proto]);
209	if (likely(ops && ops->callbacks.gso_segment))
210		segs = ops->callbacks.gso_segment(skb, features);
211
212	return segs;
213}
214
215static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
216						    struct sk_buff *skb,
217						    netdev_features_t features)
218{
219	switch (x->outer_mode.encap) {
220	case XFRM_MODE_TUNNEL:
221		return xfrm6_tunnel_gso_segment(x, skb, features);
222	case XFRM_MODE_TRANSPORT:
223		return xfrm6_transport_gso_segment(x, skb, features);
224	case XFRM_MODE_BEET:
225		return xfrm6_beet_gso_segment(x, skb, features);
226	}
227
228	return ERR_PTR(-EOPNOTSUPP);
229}
230
231static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
232				        netdev_features_t features)
233{
234	struct xfrm_state *x;
235	struct ip_esp_hdr *esph;
236	struct crypto_aead *aead;
237	netdev_features_t esp_features = features;
238	struct xfrm_offload *xo = xfrm_offload(skb);
239	struct sec_path *sp;
240
241	if (!xo)
242		return ERR_PTR(-EINVAL);
243
244	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
245		return ERR_PTR(-EINVAL);
246
247	sp = skb_sec_path(skb);
248	x = sp->xvec[sp->len - 1];
249	aead = x->data;
250	esph = ip_esp_hdr(skb);
251
252	if (esph->spi != x->id.spi)
253		return ERR_PTR(-EINVAL);
254
255	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
256		return ERR_PTR(-EINVAL);
257
258	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
259
260	skb->encap_hdr_csum = 1;
261
262	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
263		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
264					    NETIF_F_SCTP_CRC);
265	else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
266		esp_features = features & ~(NETIF_F_CSUM_MASK |
267					    NETIF_F_SCTP_CRC);
268
269	xo->flags |= XFRM_GSO_SEGMENT;
270
271	return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
272}
273
274static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
275{
276	struct crypto_aead *aead = x->data;
277	struct xfrm_offload *xo = xfrm_offload(skb);
278
279	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
280		return -EINVAL;
281
282	if (!(xo->flags & CRYPTO_DONE))
283		skb->ip_summed = CHECKSUM_NONE;
284
285	return esp6_input_done2(skb, 0);
286}
287
288static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
289{
290	int len;
291	int err;
292	int alen;
293	int blksize;
294	struct xfrm_offload *xo;
295	struct crypto_aead *aead;
296	struct esp_info esp;
297	bool hw_offload = true;
298	__u32 seq;
299
300	esp.inplace = true;
301
302	xo = xfrm_offload(skb);
303
304	if (!xo)
305		return -EINVAL;
306
307	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
308		xo->flags |= CRYPTO_FALLBACK;
309		hw_offload = false;
310	}
311
312	esp.proto = xo->proto;
313
314	/* skb is pure payload to encrypt */
315
316	aead = x->data;
317	alen = crypto_aead_authsize(aead);
318
319	esp.tfclen = 0;
320	/* XXX: Add support for tfc padding here. */
321
322	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
323	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
324	esp.plen = esp.clen - skb->len - esp.tfclen;
325	esp.tailen = esp.tfclen + esp.plen + alen;
326
327	if (!hw_offload || !skb_is_gso(skb)) {
328		esp.nfrags = esp6_output_head(x, skb, &esp);
329		if (esp.nfrags < 0)
330			return esp.nfrags;
331	}
332
333	seq = xo->seq.low;
334
335	esp.esph = ip_esp_hdr(skb);
336	esp.esph->spi = x->id.spi;
337
338	skb_push(skb, -skb_network_offset(skb));
339
340	if (xo->flags & XFRM_GSO_SEGMENT) {
341		esp.esph->seq_no = htonl(seq);
342
343		if (!skb_is_gso(skb))
344			xo->seq.low++;
345		else
346			xo->seq.low += skb_shinfo(skb)->gso_segs;
347	}
348
349	if (xo->seq.low < seq)
350		xo->seq.hi++;
351
352	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
353
354	len = skb->len - sizeof(struct ipv6hdr);
355	if (len > IPV6_MAXPLEN)
356		len = 0;
357
358	ipv6_hdr(skb)->payload_len = htons(len);
359
360	if (hw_offload) {
361		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
362			return -ENOMEM;
363
364		xo = xfrm_offload(skb);
365		if (!xo)
366			return -EINVAL;
367
368		xo->flags |= XFRM_XMIT;
369		return 0;
370	}
371
372	err = esp6_output_tail(x, skb, &esp);
373	if (err)
374		return err;
375
376	secpath_reset(skb);
377
378	if (skb_needs_linearize(skb, skb->dev->features) &&
379	    __skb_linearize(skb))
380		return -ENOMEM;
381	return 0;
382}
383
384static const struct net_offload esp6_offload = {
385	.callbacks = {
386		.gro_receive = esp6_gro_receive,
387		.gso_segment = esp6_gso_segment,
388	},
389};
390
391static const struct xfrm_type_offload esp6_type_offload = {
392	.owner		= THIS_MODULE,
393	.proto	     	= IPPROTO_ESP,
394	.input_tail	= esp6_input_tail,
395	.xmit		= esp6_xmit,
396	.encap		= esp6_gso_encap,
397};
398
399static int __init esp6_offload_init(void)
400{
401	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
402		pr_info("%s: can't add xfrm type offload\n", __func__);
403		return -EAGAIN;
404	}
405
406	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
407}
408
409static void __exit esp6_offload_exit(void)
410{
411	xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
412	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
413}
414
415module_init(esp6_offload_init);
416module_exit(esp6_offload_exit);
417MODULE_LICENSE("GPL");
418MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
419MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
420MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");
421