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	int encap_type = 0;
37	__be32 seq;
38	__be32 spi;
39
40	if (!pskb_pull(skb, offset))
41		return NULL;
42
43	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
44		goto out;
45
46	xo = xfrm_offload(skb);
47	if (!xo || !(xo->flags & CRYPTO_DONE)) {
48		struct sec_path *sp = secpath_set(skb);
49
50		if (!sp)
51			goto out;
52
53		if (sp->len == XFRM_MAX_DEPTH)
54			goto out_reset;
55
56		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
57				      (xfrm_address_t *)&ip_hdr(skb)->daddr,
58				      spi, IPPROTO_ESP, AF_INET);
59		if (!x)
60			goto out_reset;
61
62		skb->mark = xfrm_smark_get(skb->mark, x);
63
64		sp->xvec[sp->len++] = x;
65		sp->olen++;
66
67		xo = xfrm_offload(skb);
68		if (!xo)
69			goto out_reset;
70	}
71
72	xo->flags |= XFRM_GRO;
73
74	if (NAPI_GRO_CB(skb)->proto == IPPROTO_UDP)
75		encap_type = UDP_ENCAP_ESPINUDP;
76
77	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
78	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
79	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
80	XFRM_SPI_SKB_CB(skb)->seq = seq;
81
82	/* We don't need to handle errors from xfrm_input, it does all
83	 * the error handling and frees the resources on error. */
84	xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
85
86	return ERR_PTR(-EINPROGRESS);
87out_reset:
88	secpath_reset(skb);
89out:
90	skb_push(skb, offset);
91	NAPI_GRO_CB(skb)->same_flow = 0;
92	NAPI_GRO_CB(skb)->flush = 1;
93
94	return NULL;
95}
96
97static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
98{
99	struct ip_esp_hdr *esph;
100	struct iphdr *iph = ip_hdr(skb);
101	struct xfrm_offload *xo = xfrm_offload(skb);
102	int proto = iph->protocol;
103
104	skb_push(skb, -skb_network_offset(skb));
105	esph = ip_esp_hdr(skb);
106	*skb_mac_header(skb) = IPPROTO_ESP;
107
108	esph->spi = x->id.spi;
109	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
110
111	xo->proto = proto;
112}
113
114static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
115						struct sk_buff *skb,
116						netdev_features_t features)
117{
118	__be16 type = x->inner_mode.family == AF_INET6 ? htons(ETH_P_IPV6)
119						       : htons(ETH_P_IP);
120
121	return skb_eth_gso_segment(skb, features, type);
122}
123
124static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
125						   struct sk_buff *skb,
126						   netdev_features_t features)
127{
128	const struct net_offload *ops;
129	struct sk_buff *segs = ERR_PTR(-EINVAL);
130	struct xfrm_offload *xo = xfrm_offload(skb);
131
132	skb->transport_header += x->props.header_len;
133	ops = rcu_dereference(inet_offloads[xo->proto]);
134	if (likely(ops && ops->callbacks.gso_segment))
135		segs = ops->callbacks.gso_segment(skb, features);
136
137	return segs;
138}
139
140static struct sk_buff *xfrm4_beet_gso_segment(struct xfrm_state *x,
141					      struct sk_buff *skb,
142					      netdev_features_t features)
143{
144	struct xfrm_offload *xo = xfrm_offload(skb);
145	struct sk_buff *segs = ERR_PTR(-EINVAL);
146	const struct net_offload *ops;
147	u8 proto = xo->proto;
148
149	skb->transport_header += x->props.header_len;
150
151	if (x->sel.family != AF_INET6) {
152		if (proto == IPPROTO_BEETPH) {
153			struct ip_beet_phdr *ph =
154				(struct ip_beet_phdr *)skb->data;
155
156			skb->transport_header += ph->hdrlen * 8;
157			proto = ph->nexthdr;
158		} else {
159			skb->transport_header -= IPV4_BEET_PHMAXLEN;
160		}
161	} else {
162		__be16 frag;
163
164		skb->transport_header +=
165			ipv6_skip_exthdr(skb, 0, &proto, &frag);
166		if (proto == IPPROTO_TCP)
167			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
168	}
169
170	if (proto == IPPROTO_IPV6)
171		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
172
173	__skb_pull(skb, skb_transport_offset(skb));
174	ops = rcu_dereference(inet_offloads[proto]);
175	if (likely(ops && ops->callbacks.gso_segment))
176		segs = ops->callbacks.gso_segment(skb, features);
177
178	return segs;
179}
180
181static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
182						    struct sk_buff *skb,
183						    netdev_features_t features)
184{
185	switch (x->outer_mode.encap) {
186	case XFRM_MODE_TUNNEL:
187		return xfrm4_tunnel_gso_segment(x, skb, features);
188	case XFRM_MODE_TRANSPORT:
189		return xfrm4_transport_gso_segment(x, skb, features);
190	case XFRM_MODE_BEET:
191		return xfrm4_beet_gso_segment(x, skb, features);
192	}
193
194	return ERR_PTR(-EOPNOTSUPP);
195}
196
197static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
198				        netdev_features_t features)
199{
200	struct xfrm_state *x;
201	struct ip_esp_hdr *esph;
202	struct crypto_aead *aead;
203	netdev_features_t esp_features = features;
204	struct xfrm_offload *xo = xfrm_offload(skb);
205	struct sec_path *sp;
206
207	if (!xo)
208		return ERR_PTR(-EINVAL);
209
210	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
211		return ERR_PTR(-EINVAL);
212
213	sp = skb_sec_path(skb);
214	x = sp->xvec[sp->len - 1];
215	aead = x->data;
216	esph = ip_esp_hdr(skb);
217
218	if (esph->spi != x->id.spi)
219		return ERR_PTR(-EINVAL);
220
221	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
222		return ERR_PTR(-EINVAL);
223
224	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
225
226	skb->encap_hdr_csum = 1;
227
228	if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
229	     !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
230		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
231					    NETIF_F_SCTP_CRC);
232	else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
233		 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
234		esp_features = features & ~(NETIF_F_CSUM_MASK |
235					    NETIF_F_SCTP_CRC);
236
237	xo->flags |= XFRM_GSO_SEGMENT;
238
239	return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
240}
241
242static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
243{
244	struct crypto_aead *aead = x->data;
245	struct xfrm_offload *xo = xfrm_offload(skb);
246
247	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
248		return -EINVAL;
249
250	if (!(xo->flags & CRYPTO_DONE))
251		skb->ip_summed = CHECKSUM_NONE;
252
253	return esp_input_done2(skb, 0);
254}
255
256static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
257{
258	int err;
259	int alen;
260	int blksize;
261	struct xfrm_offload *xo;
262	struct ip_esp_hdr *esph;
263	struct crypto_aead *aead;
264	struct esp_info esp;
265	bool hw_offload = true;
266	__u32 seq;
267
268	esp.inplace = true;
269
270	xo = xfrm_offload(skb);
271
272	if (!xo)
273		return -EINVAL;
274
275	if ((!(features & NETIF_F_HW_ESP) &&
276	     !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
277	    x->xso.dev != skb->dev) {
278		xo->flags |= CRYPTO_FALLBACK;
279		hw_offload = false;
280	}
281
282	esp.proto = xo->proto;
283
284	/* skb is pure payload to encrypt */
285
286	aead = x->data;
287	alen = crypto_aead_authsize(aead);
288
289	esp.tfclen = 0;
290	/* XXX: Add support for tfc padding here. */
291
292	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
293	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
294	esp.plen = esp.clen - skb->len - esp.tfclen;
295	esp.tailen = esp.tfclen + esp.plen + alen;
296
297	esp.esph = ip_esp_hdr(skb);
298
299
300	if (!hw_offload || !skb_is_gso(skb)) {
301		esp.nfrags = esp_output_head(x, skb, &esp);
302		if (esp.nfrags < 0)
303			return esp.nfrags;
304	}
305
306	seq = xo->seq.low;
307
308	esph = esp.esph;
309	esph->spi = x->id.spi;
310
311	skb_push(skb, -skb_network_offset(skb));
312
313	if (xo->flags & XFRM_GSO_SEGMENT) {
314		esph->seq_no = htonl(seq);
315
316		if (!skb_is_gso(skb))
317			xo->seq.low++;
318		else
319			xo->seq.low += skb_shinfo(skb)->gso_segs;
320	}
321
322	if (xo->seq.low < seq)
323		xo->seq.hi++;
324
325	esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
326
327	ip_hdr(skb)->tot_len = htons(skb->len);
328	ip_send_check(ip_hdr(skb));
329
330	if (hw_offload) {
331		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
332			return -ENOMEM;
333
334		xo = xfrm_offload(skb);
335		if (!xo)
336			return -EINVAL;
337
338		xo->flags |= XFRM_XMIT;
339		return 0;
340	}
341
342	err = esp_output_tail(x, skb, &esp);
343	if (err)
344		return err;
345
346	secpath_reset(skb);
347
348	if (skb_needs_linearize(skb, skb->dev->features) &&
349	    __skb_linearize(skb))
350		return -ENOMEM;
351	return 0;
352}
353
354static const struct net_offload esp4_offload = {
355	.callbacks = {
356		.gro_receive = esp4_gro_receive,
357		.gso_segment = esp4_gso_segment,
358	},
359};
360
361static const struct xfrm_type_offload esp_type_offload = {
362	.owner		= THIS_MODULE,
363	.proto	     	= IPPROTO_ESP,
364	.input_tail	= esp_input_tail,
365	.xmit		= esp_xmit,
366	.encap		= esp4_gso_encap,
367};
368
369static int __init esp4_offload_init(void)
370{
371	if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
372		pr_info("%s: can't add xfrm type offload\n", __func__);
373		return -EAGAIN;
374	}
375
376	return inet_add_offload(&esp4_offload, IPPROTO_ESP);
377}
378
379static void __exit esp4_offload_exit(void)
380{
381	xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
382	inet_del_offload(&esp4_offload, IPPROTO_ESP);
383}
384
385module_init(esp4_offload_init);
386module_exit(esp4_offload_exit);
387MODULE_LICENSE("GPL");
388MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
389MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
390MODULE_DESCRIPTION("IPV4 GSO/GRO offload support");
391