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	/* ESP or ESPINUDP */
38	if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP ||
39		   ipv6_hdr->nexthdr == NEXTHDR_UDP))
40		return offsetof(struct ipv6hdr, nexthdr);
41
42	while (off < nhlen) {
43		exthdr = (void *)ipv6_hdr + off;
44		if (exthdr->nexthdr == NEXTHDR_ESP)
45			return off;
46
47		off += ipv6_optlen(exthdr);
48	}
49
50	return 0;
51}
52
53static struct sk_buff *esp6_gro_receive(struct list_head *head,
54					struct sk_buff *skb)
55{
56	int offset = skb_gro_offset(skb);
57	struct xfrm_offload *xo;
58	struct xfrm_state *x;
59	int encap_type = 0;
60	__be32 seq;
61	__be32 spi;
62	int nhoff;
63
64	if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP)
65		encap_type = UDP_ENCAP_ESPINUDP;
66
67	if (!pskb_pull(skb, offset))
68		return NULL;
69
70	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
71		goto out;
72
73	xo = xfrm_offload(skb);
74	if (!xo || !(xo->flags & CRYPTO_DONE)) {
75		struct sec_path *sp = secpath_set(skb);
76
77		if (!sp)
78			goto out;
79
80		if (sp->len == XFRM_MAX_DEPTH)
81			goto out_reset;
82
83		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
84				      (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
85				      spi, IPPROTO_ESP, AF_INET6);
86		if (!x)
87			goto out_reset;
88
89		skb->mark = xfrm_smark_get(skb->mark, x);
90
91		sp->xvec[sp->len++] = x;
92		sp->olen++;
93
94		xo = xfrm_offload(skb);
95		if (!xo)
96			goto out_reset;
97	}
98
99	xo->flags |= XFRM_GRO;
100
101	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
102	if (!nhoff)
103		goto out;
104
105	IP6CB(skb)->nhoff = nhoff;
106	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
107	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
108	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
109	XFRM_SPI_SKB_CB(skb)->seq = seq;
110
111	/* We don't need to handle errors from xfrm_input, it does all
112	 * the error handling and frees the resources on error. */
113	xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
114
115	return ERR_PTR(-EINPROGRESS);
116out_reset:
117	secpath_reset(skb);
118out:
119	skb_push(skb, offset);
120	NAPI_GRO_CB(skb)->same_flow = 0;
121	NAPI_GRO_CB(skb)->flush = 1;
122
123	return NULL;
124}
125
126static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
127{
128	struct ip_esp_hdr *esph;
129	struct ipv6hdr *iph = ipv6_hdr(skb);
130	struct xfrm_offload *xo = xfrm_offload(skb);
131	u8 proto = iph->nexthdr;
132
133	skb_push(skb, -skb_network_offset(skb));
134
135	if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
136		__be16 frag;
137
138		ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
139	}
140
141	esph = ip_esp_hdr(skb);
142	*skb_mac_header(skb) = IPPROTO_ESP;
143
144	esph->spi = x->id.spi;
145	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
146
147	xo->proto = proto;
148}
149
150static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
151						struct sk_buff *skb,
152						netdev_features_t features)
153{
154	__be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
155						      : htons(ETH_P_IPV6);
156
157	return skb_eth_gso_segment(skb, features, type);
158}
159
160static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
161						   struct sk_buff *skb,
162						   netdev_features_t features)
163{
164	const struct net_offload *ops;
165	struct sk_buff *segs = ERR_PTR(-EINVAL);
166	struct xfrm_offload *xo = xfrm_offload(skb);
167
168	skb->transport_header += x->props.header_len;
169	ops = rcu_dereference(inet6_offloads[xo->proto]);
170	if (likely(ops && ops->callbacks.gso_segment))
171		segs = ops->callbacks.gso_segment(skb, features);
172
173	return segs;
174}
175
176static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
177					      struct sk_buff *skb,
178					      netdev_features_t features)
179{
180	struct xfrm_offload *xo = xfrm_offload(skb);
181	struct sk_buff *segs = ERR_PTR(-EINVAL);
182	const struct net_offload *ops;
183	u8 proto = xo->proto;
184
185	skb->transport_header += x->props.header_len;
186
187	if (x->sel.family != AF_INET6) {
188		skb->transport_header -=
189			(sizeof(struct ipv6hdr) - sizeof(struct iphdr));
190
191		if (proto == IPPROTO_BEETPH) {
192			struct ip_beet_phdr *ph =
193				(struct ip_beet_phdr *)skb->data;
194
195			skb->transport_header += ph->hdrlen * 8;
196			proto = ph->nexthdr;
197		} else {
198			skb->transport_header -= IPV4_BEET_PHMAXLEN;
199		}
200
201		if (proto == IPPROTO_TCP)
202			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
203	} else {
204		__be16 frag;
205
206		skb->transport_header +=
207			ipv6_skip_exthdr(skb, 0, &proto, &frag);
208	}
209
210	if (proto == IPPROTO_IPIP)
211		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
212
213	__skb_pull(skb, skb_transport_offset(skb));
214	ops = rcu_dereference(inet6_offloads[proto]);
215	if (likely(ops && ops->callbacks.gso_segment))
216		segs = ops->callbacks.gso_segment(skb, features);
217
218	return segs;
219}
220
221static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
222						    struct sk_buff *skb,
223						    netdev_features_t features)
224{
225	switch (x->outer_mode.encap) {
226	case XFRM_MODE_TUNNEL:
227		return xfrm6_tunnel_gso_segment(x, skb, features);
228	case XFRM_MODE_TRANSPORT:
229		return xfrm6_transport_gso_segment(x, skb, features);
230	case XFRM_MODE_BEET:
231		return xfrm6_beet_gso_segment(x, skb, features);
232	}
233
234	return ERR_PTR(-EOPNOTSUPP);
235}
236
237static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
238				        netdev_features_t features)
239{
240	struct xfrm_state *x;
241	struct ip_esp_hdr *esph;
242	struct crypto_aead *aead;
243	netdev_features_t esp_features = features;
244	struct xfrm_offload *xo = xfrm_offload(skb);
245	struct sec_path *sp;
246
247	if (!xo)
248		return ERR_PTR(-EINVAL);
249
250	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
251		return ERR_PTR(-EINVAL);
252
253	sp = skb_sec_path(skb);
254	x = sp->xvec[sp->len - 1];
255	aead = x->data;
256	esph = ip_esp_hdr(skb);
257
258	if (esph->spi != x->id.spi)
259		return ERR_PTR(-EINVAL);
260
261	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
262		return ERR_PTR(-EINVAL);
263
264	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
265
266	skb->encap_hdr_csum = 1;
267
268	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
269		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
270					    NETIF_F_SCTP_CRC);
271	else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
272		esp_features = features & ~(NETIF_F_CSUM_MASK |
273					    NETIF_F_SCTP_CRC);
274
275	xo->flags |= XFRM_GSO_SEGMENT;
276
277	return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
278}
279
280static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
281{
282	struct crypto_aead *aead = x->data;
283	struct xfrm_offload *xo = xfrm_offload(skb);
284
285	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
286		return -EINVAL;
287
288	if (!(xo->flags & CRYPTO_DONE))
289		skb->ip_summed = CHECKSUM_NONE;
290
291	return esp6_input_done2(skb, 0);
292}
293
294static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
295{
296	int len;
297	int err;
298	int alen;
299	int blksize;
300	struct xfrm_offload *xo;
301	struct crypto_aead *aead;
302	struct esp_info esp;
303	bool hw_offload = true;
304	__u32 seq;
305
306	esp.inplace = true;
307
308	xo = xfrm_offload(skb);
309
310	if (!xo)
311		return -EINVAL;
312
313	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
314		xo->flags |= CRYPTO_FALLBACK;
315		hw_offload = false;
316	}
317
318	esp.proto = xo->proto;
319
320	/* skb is pure payload to encrypt */
321
322	aead = x->data;
323	alen = crypto_aead_authsize(aead);
324
325	esp.tfclen = 0;
326	/* XXX: Add support for tfc padding here. */
327
328	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
329	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
330	esp.plen = esp.clen - skb->len - esp.tfclen;
331	esp.tailen = esp.tfclen + esp.plen + alen;
332
333	if (!hw_offload || !skb_is_gso(skb)) {
334		esp.nfrags = esp6_output_head(x, skb, &esp);
335		if (esp.nfrags < 0)
336			return esp.nfrags;
337	}
338
339	seq = xo->seq.low;
340
341	esp.esph = ip_esp_hdr(skb);
342	esp.esph->spi = x->id.spi;
343
344	skb_push(skb, -skb_network_offset(skb));
345
346	if (xo->flags & XFRM_GSO_SEGMENT) {
347		esp.esph->seq_no = htonl(seq);
348
349		if (!skb_is_gso(skb))
350			xo->seq.low++;
351		else
352			xo->seq.low += skb_shinfo(skb)->gso_segs;
353	}
354
355	if (xo->seq.low < seq)
356		xo->seq.hi++;
357
358	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
359
360	len = skb->len - sizeof(struct ipv6hdr);
361	if (len > IPV6_MAXPLEN)
362		len = 0;
363
364	ipv6_hdr(skb)->payload_len = htons(len);
365
366	if (hw_offload) {
367		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
368			return -ENOMEM;
369
370		xo = xfrm_offload(skb);
371		if (!xo)
372			return -EINVAL;
373
374		xo->flags |= XFRM_XMIT;
375		return 0;
376	}
377
378	err = esp6_output_tail(x, skb, &esp);
379	if (err)
380		return err;
381
382	secpath_reset(skb);
383
384	if (skb_needs_linearize(skb, skb->dev->features) &&
385	    __skb_linearize(skb))
386		return -ENOMEM;
387	return 0;
388}
389
390static const struct net_offload esp6_offload = {
391	.callbacks = {
392		.gro_receive = esp6_gro_receive,
393		.gso_segment = esp6_gso_segment,
394	},
395};
396
397static const struct xfrm_type_offload esp6_type_offload = {
398	.owner		= THIS_MODULE,
399	.proto	     	= IPPROTO_ESP,
400	.input_tail	= esp6_input_tail,
401	.xmit		= esp6_xmit,
402	.encap		= esp6_gso_encap,
403};
404
405static int __init esp6_offload_init(void)
406{
407	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
408		pr_info("%s: can't add xfrm type offload\n", __func__);
409		return -EAGAIN;
410	}
411
412	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
413}
414
415static void __exit esp6_offload_exit(void)
416{
417	xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
418	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
419}
420
421module_init(esp6_offload_init);
422module_exit(esp6_offload_exit);
423MODULE_LICENSE("GPL");
424MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
425MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
426MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");
427