xref: /kernel/linux/linux-6.6/net/ipv4/esp4_offload.c (revision 62306a36) 
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/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/udp.h>
29
30static struct sk_buff *esp4_gro_receive(struct list_head *head,
31					struct sk_buff *skb)
32{
33	int offset = skb_gro_offset(skb);
34	struct xfrm_offload *xo;
35	struct xfrm_state *x;
36	__be32 seq;
37	__be32 spi;
38
39	if (!pskb_pull(skb, offset))
40		return NULL;
41
42	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
43		goto out;
44
45	xo = xfrm_offload(skb);
46	if (!xo || !(xo->flags & CRYPTO_DONE)) {
47		struct sec_path *sp = secpath_set(skb);
48
49		if (!sp)
50			goto out;
51
52		if (sp->len == XFRM_MAX_DEPTH)
53			goto out_reset;
54
55		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
56				      (xfrm_address_t *)&ip_hdr(skb)->daddr,
57				      spi, IPPROTO_ESP, AF_INET);
58		if (!x)
59			goto out_reset;
60
61		skb->mark = xfrm_smark_get(skb->mark, x);
62
63		sp->xvec[sp->len++] = x;
64		sp->olen++;
65
66		xo = xfrm_offload(skb);
67		if (!xo)
68			goto out_reset;
69	}
70
71	xo->flags |= XFRM_GRO;
72
73	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
74	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
75	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
76	XFRM_SPI_SKB_CB(skb)->seq = seq;
77
78	/* We don't need to handle errors from xfrm_input, it does all
79	 * the error handling and frees the resources on error. */
80	xfrm_input(skb, IPPROTO_ESP, spi, -2);
81
82	return ERR_PTR(-EINPROGRESS);
83out_reset:
84	secpath_reset(skb);
85out:
86	skb_push(skb, offset);
87	NAPI_GRO_CB(skb)->same_flow = 0;
88	NAPI_GRO_CB(skb)->flush = 1;
89
90	return NULL;
91}
92
93static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
94{
95	struct ip_esp_hdr *esph;
96	struct iphdr *iph = ip_hdr(skb);
97	struct xfrm_offload *xo = xfrm_offload(skb);
98	int proto = iph->protocol;
99
100	skb_push(skb, -skb_network_offset(skb));
101	esph = ip_esp_hdr(skb);
102	*skb_mac_header(skb) = IPPROTO_ESP;
103
104	esph->spi = x->id.spi;
105	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
106
107	xo->proto = proto;
108}
109
110static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
111						struct sk_buff *skb,
112						netdev_features_t features)
113{
114	__be16 type = x->inner_mode.family == AF_INET6 ? htons(ETH_P_IPV6)
115						       : htons(ETH_P_IP);
116
117	return skb_eth_gso_segment(skb, features, type);
118}
119
120static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
121						   struct sk_buff *skb,
122						   netdev_features_t features)
123{
124	const struct net_offload *ops;
125	struct sk_buff *segs = ERR_PTR(-EINVAL);
126	struct xfrm_offload *xo = xfrm_offload(skb);
127
128	skb->transport_header += x->props.header_len;
129	ops = rcu_dereference(inet_offloads[xo->proto]);
130	if (likely(ops && ops->callbacks.gso_segment))
131		segs = ops->callbacks.gso_segment(skb, features);
132
133	return segs;
134}
135
136static struct sk_buff *xfrm4_beet_gso_segment(struct xfrm_state *x,
137					      struct sk_buff *skb,
138					      netdev_features_t features)
139{
140	struct xfrm_offload *xo = xfrm_offload(skb);
141	struct sk_buff *segs = ERR_PTR(-EINVAL);
142	const struct net_offload *ops;
143	u8 proto = xo->proto;
144
145	skb->transport_header += x->props.header_len;
146
147	if (x->sel.family != AF_INET6) {
148		if (proto == IPPROTO_BEETPH) {
149			struct ip_beet_phdr *ph =
150				(struct ip_beet_phdr *)skb->data;
151
152			skb->transport_header += ph->hdrlen * 8;
153			proto = ph->nexthdr;
154		} else {
155			skb->transport_header -= IPV4_BEET_PHMAXLEN;
156		}
157	} else {
158		__be16 frag;
159
160		skb->transport_header +=
161			ipv6_skip_exthdr(skb, 0, &proto, &frag);
162		if (proto == IPPROTO_TCP)
163			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
164	}
165
166	if (proto == IPPROTO_IPV6)
167		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
168
169	__skb_pull(skb, skb_transport_offset(skb));
170	ops = rcu_dereference(inet_offloads[proto]);
171	if (likely(ops && ops->callbacks.gso_segment))
172		segs = ops->callbacks.gso_segment(skb, features);
173
174	return segs;
175}
176
177static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
178						    struct sk_buff *skb,
179						    netdev_features_t features)
180{
181	switch (x->outer_mode.encap) {
182	case XFRM_MODE_TUNNEL:
183		return xfrm4_tunnel_gso_segment(x, skb, features);
184	case XFRM_MODE_TRANSPORT:
185		return xfrm4_transport_gso_segment(x, skb, features);
186	case XFRM_MODE_BEET:
187		return xfrm4_beet_gso_segment(x, skb, features);
188	}
189
190	return ERR_PTR(-EOPNOTSUPP);
191}
192
193static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
194				        netdev_features_t features)
195{
196	struct xfrm_state *x;
197	struct ip_esp_hdr *esph;
198	struct crypto_aead *aead;
199	netdev_features_t esp_features = features;
200	struct xfrm_offload *xo = xfrm_offload(skb);
201	struct sec_path *sp;
202
203	if (!xo)
204		return ERR_PTR(-EINVAL);
205
206	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
207		return ERR_PTR(-EINVAL);
208
209	sp = skb_sec_path(skb);
210	x = sp->xvec[sp->len - 1];
211	aead = x->data;
212	esph = ip_esp_hdr(skb);
213
214	if (esph->spi != x->id.spi)
215		return ERR_PTR(-EINVAL);
216
217	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
218		return ERR_PTR(-EINVAL);
219
220	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
221
222	skb->encap_hdr_csum = 1;
223
224	if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
225	     !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
226		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
227					    NETIF_F_SCTP_CRC);
228	else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
229		 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
230		esp_features = features & ~(NETIF_F_CSUM_MASK |
231					    NETIF_F_SCTP_CRC);
232
233	xo->flags |= XFRM_GSO_SEGMENT;
234
235	return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
236}
237
238static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
239{
240	struct crypto_aead *aead = x->data;
241	struct xfrm_offload *xo = xfrm_offload(skb);
242
243	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
244		return -EINVAL;
245
246	if (!(xo->flags & CRYPTO_DONE))
247		skb->ip_summed = CHECKSUM_NONE;
248
249	return esp_input_done2(skb, 0);
250}
251
252static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
253{
254	int err;
255	int alen;
256	int blksize;
257	struct xfrm_offload *xo;
258	struct ip_esp_hdr *esph;
259	struct crypto_aead *aead;
260	struct esp_info esp;
261	bool hw_offload = true;
262	__u32 seq;
263
264	esp.inplace = true;
265
266	xo = xfrm_offload(skb);
267
268	if (!xo)
269		return -EINVAL;
270
271	if ((!(features & NETIF_F_HW_ESP) &&
272	     !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
273	    x->xso.dev != skb->dev) {
274		xo->flags |= CRYPTO_FALLBACK;
275		hw_offload = false;
276	}
277
278	esp.proto = xo->proto;
279
280	/* skb is pure payload to encrypt */
281
282	aead = x->data;
283	alen = crypto_aead_authsize(aead);
284
285	esp.tfclen = 0;
286	/* XXX: Add support for tfc padding here. */
287
288	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
289	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
290	esp.plen = esp.clen - skb->len - esp.tfclen;
291	esp.tailen = esp.tfclen + esp.plen + alen;
292
293	esp.esph = ip_esp_hdr(skb);
294
295
296	if (!hw_offload || !skb_is_gso(skb)) {
297		esp.nfrags = esp_output_head(x, skb, &esp);
298		if (esp.nfrags < 0)
299			return esp.nfrags;
300	}
301
302	seq = xo->seq.low;
303
304	esph = esp.esph;
305	esph->spi = x->id.spi;
306
307	skb_push(skb, -skb_network_offset(skb));
308
309	if (xo->flags & XFRM_GSO_SEGMENT) {
310		esph->seq_no = htonl(seq);
311
312		if (!skb_is_gso(skb))
313			xo->seq.low++;
314		else
315			xo->seq.low += skb_shinfo(skb)->gso_segs;
316	}
317
318	if (xo->seq.low < seq)
319		xo->seq.hi++;
320
321	esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
322
323	ip_hdr(skb)->tot_len = htons(skb->len);
324	ip_send_check(ip_hdr(skb));
325
326	if (hw_offload) {
327		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
328			return -ENOMEM;
329
330		xo = xfrm_offload(skb);
331		if (!xo)
332			return -EINVAL;
333
334		xo->flags |= XFRM_XMIT;
335		return 0;
336	}
337
338	err = esp_output_tail(x, skb, &esp);
339	if (err)
340		return err;
341
342	secpath_reset(skb);
343
344	if (skb_needs_linearize(skb, skb->dev->features) &&
345	    __skb_linearize(skb))
346		return -ENOMEM;
347	return 0;
348}
349
350static const struct net_offload esp4_offload = {
351	.callbacks = {
352		.gro_receive = esp4_gro_receive,
353		.gso_segment = esp4_gso_segment,
354	},
355};
356
357static const struct xfrm_type_offload esp_type_offload = {
358	.owner		= THIS_MODULE,
359	.proto	     	= IPPROTO_ESP,
360	.input_tail	= esp_input_tail,
361	.xmit		= esp_xmit,
362	.encap		= esp4_gso_encap,
363};
364
365static int __init esp4_offload_init(void)
366{
367	if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
368		pr_info("%s: can't add xfrm type offload\n", __func__);
369		return -EAGAIN;
370	}
371
372	return inet_add_offload(&esp4_offload, IPPROTO_ESP);
373}
374
375static void __exit esp4_offload_exit(void)
376{
377	xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
378	inet_del_offload(&esp4_offload, IPPROTO_ESP);
379}
380
381module_init(esp4_offload_init);
382module_exit(esp4_offload_exit);
383MODULE_LICENSE("GPL");
384MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
385MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
386MODULE_DESCRIPTION("IPV4 GSO/GRO offload support");
387