xref: /linux/net/ipv6/esp6_offload.c (revision 300a90b2cb5d442879e6398920c49aebbd5c8e40) 
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 
32 static __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 
53 static 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 
87 		if (unlikely(x && x->dir && x->dir != XFRM_SA_DIR_IN)) {
88 			/* non-offload path will record the error and audit log */
89 			xfrm_state_put(x);
90 			x = NULL;
91 		}
92 
93 		if (!x)
94 			goto out_reset;
95 
96 		skb->mark = xfrm_smark_get(skb->mark, x);
97 
98 		sp->xvec[sp->len++] = x;
99 		sp->olen++;
100 
101 		xo = xfrm_offload(skb);
102 		if (!xo)
103 			goto out_reset;
104 	}
105 
106 	xo->flags |= XFRM_GRO;
107 
108 	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
109 	if (!nhoff)
110 		goto out;
111 
112 	IP6CB(skb)->nhoff = nhoff;
113 	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
114 	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
115 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
116 	XFRM_SPI_SKB_CB(skb)->seq = seq;
117 
118 	/* We don't need to handle errors from xfrm_input, it does all
119 	 * the error handling and frees the resources on error. */
120 	xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
121 
122 	return ERR_PTR(-EINPROGRESS);
123 out_reset:
124 	secpath_reset(skb);
125 out:
126 	skb_push(skb, offset);
127 	NAPI_GRO_CB(skb)->same_flow = 0;
128 	NAPI_GRO_CB(skb)->flush = 1;
129 
130 	return NULL;
131 }
132 
133 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
134 {
135 	struct ip_esp_hdr *esph;
136 	struct ipv6hdr *iph = ipv6_hdr(skb);
137 	struct xfrm_offload *xo = xfrm_offload(skb);
138 	u8 proto = iph->nexthdr;
139 
140 	skb_push(skb, -skb_network_offset(skb));
141 
142 	if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
143 		__be16 frag;
144 
145 		ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
146 	}
147 
148 	esph = ip_esp_hdr(skb);
149 	*skb_mac_header(skb) = IPPROTO_ESP;
150 
151 	esph->spi = x->id.spi;
152 	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
153 
154 	xo->proto = proto;
155 }
156 
157 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
158 						struct sk_buff *skb,
159 						netdev_features_t features)
160 {
161 	__be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
162 						      : htons(ETH_P_IPV6);
163 
164 	return skb_eth_gso_segment(skb, features, type);
165 }
166 
167 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
168 						   struct sk_buff *skb,
169 						   netdev_features_t features)
170 {
171 	const struct net_offload *ops;
172 	struct sk_buff *segs = ERR_PTR(-EINVAL);
173 	struct xfrm_offload *xo = xfrm_offload(skb);
174 
175 	skb->transport_header += x->props.header_len;
176 	ops = rcu_dereference(inet6_offloads[xo->proto]);
177 	if (likely(ops && ops->callbacks.gso_segment))
178 		segs = ops->callbacks.gso_segment(skb, features);
179 
180 	return segs;
181 }
182 
183 static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
184 					      struct sk_buff *skb,
185 					      netdev_features_t features)
186 {
187 	struct xfrm_offload *xo = xfrm_offload(skb);
188 	struct sk_buff *segs = ERR_PTR(-EINVAL);
189 	const struct net_offload *ops;
190 	u8 proto = xo->proto;
191 
192 	skb->transport_header += x->props.header_len;
193 
194 	if (x->sel.family != AF_INET6) {
195 		skb->transport_header -=
196 			(sizeof(struct ipv6hdr) - sizeof(struct iphdr));
197 
198 		if (proto == IPPROTO_BEETPH) {
199 			struct ip_beet_phdr *ph =
200 				(struct ip_beet_phdr *)skb->data;
201 
202 			skb->transport_header += ph->hdrlen * 8;
203 			proto = ph->nexthdr;
204 		} else {
205 			skb->transport_header -= IPV4_BEET_PHMAXLEN;
206 		}
207 
208 		if (proto == IPPROTO_TCP)
209 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
210 	} else {
211 		__be16 frag;
212 
213 		skb->transport_header +=
214 			ipv6_skip_exthdr(skb, 0, &proto, &frag);
215 	}
216 
217 	if (proto == IPPROTO_IPIP)
218 		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
219 
220 	__skb_pull(skb, skb_transport_offset(skb));
221 	ops = rcu_dereference(inet6_offloads[proto]);
222 	if (likely(ops && ops->callbacks.gso_segment))
223 		segs = ops->callbacks.gso_segment(skb, features);
224 
225 	return segs;
226 }
227 
228 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
229 						    struct sk_buff *skb,
230 						    netdev_features_t features)
231 {
232 	switch (x->outer_mode.encap) {
233 	case XFRM_MODE_TUNNEL:
234 		return xfrm6_tunnel_gso_segment(x, skb, features);
235 	case XFRM_MODE_TRANSPORT:
236 		return xfrm6_transport_gso_segment(x, skb, features);
237 	case XFRM_MODE_BEET:
238 		return xfrm6_beet_gso_segment(x, skb, features);
239 	}
240 
241 	return ERR_PTR(-EOPNOTSUPP);
242 }
243 
244 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
245 				        netdev_features_t features)
246 {
247 	struct xfrm_state *x;
248 	struct ip_esp_hdr *esph;
249 	struct crypto_aead *aead;
250 	netdev_features_t esp_features = features;
251 	struct xfrm_offload *xo = xfrm_offload(skb);
252 	struct sec_path *sp;
253 
254 	if (!xo)
255 		return ERR_PTR(-EINVAL);
256 
257 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
258 		return ERR_PTR(-EINVAL);
259 
260 	sp = skb_sec_path(skb);
261 	x = sp->xvec[sp->len - 1];
262 	aead = x->data;
263 	esph = ip_esp_hdr(skb);
264 
265 	if (esph->spi != x->id.spi)
266 		return ERR_PTR(-EINVAL);
267 
268 	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
269 		return ERR_PTR(-EINVAL);
270 
271 	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
272 
273 	skb->encap_hdr_csum = 1;
274 
275 	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
276 		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
277 					    NETIF_F_SCTP_CRC);
278 	else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
279 		esp_features = features & ~(NETIF_F_CSUM_MASK |
280 					    NETIF_F_SCTP_CRC);
281 
282 	xo->flags |= XFRM_GSO_SEGMENT;
283 
284 	return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
285 }
286 
287 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
288 {
289 	struct crypto_aead *aead = x->data;
290 	struct xfrm_offload *xo = xfrm_offload(skb);
291 
292 	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
293 		return -EINVAL;
294 
295 	if (!(xo->flags & CRYPTO_DONE))
296 		skb->ip_summed = CHECKSUM_NONE;
297 
298 	return esp6_input_done2(skb, 0);
299 }
300 
301 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
302 {
303 	int len;
304 	int err;
305 	int alen;
306 	int blksize;
307 	struct xfrm_offload *xo;
308 	struct crypto_aead *aead;
309 	struct esp_info esp;
310 	bool hw_offload = true;
311 	__u32 seq;
312 
313 	esp.inplace = true;
314 
315 	xo = xfrm_offload(skb);
316 
317 	if (!xo)
318 		return -EINVAL;
319 
320 	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
321 		xo->flags |= CRYPTO_FALLBACK;
322 		hw_offload = false;
323 	}
324 
325 	esp.proto = xo->proto;
326 
327 	/* skb is pure payload to encrypt */
328 
329 	aead = x->data;
330 	alen = crypto_aead_authsize(aead);
331 
332 	esp.tfclen = 0;
333 	/* XXX: Add support for tfc padding here. */
334 
335 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
336 	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
337 	esp.plen = esp.clen - skb->len - esp.tfclen;
338 	esp.tailen = esp.tfclen + esp.plen + alen;
339 
340 	if (!hw_offload || !skb_is_gso(skb)) {
341 		esp.nfrags = esp6_output_head(x, skb, &esp);
342 		if (esp.nfrags < 0)
343 			return esp.nfrags;
344 	}
345 
346 	seq = xo->seq.low;
347 
348 	esp.esph = ip_esp_hdr(skb);
349 	esp.esph->spi = x->id.spi;
350 
351 	skb_push(skb, -skb_network_offset(skb));
352 
353 	if (xo->flags & XFRM_GSO_SEGMENT) {
354 		esp.esph->seq_no = htonl(seq);
355 
356 		if (!skb_is_gso(skb))
357 			xo->seq.low++;
358 		else
359 			xo->seq.low += skb_shinfo(skb)->gso_segs;
360 	}
361 
362 	if (xo->seq.low < seq)
363 		xo->seq.hi++;
364 
365 	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
366 
367 	len = skb->len - sizeof(struct ipv6hdr);
368 	if (len > IPV6_MAXPLEN)
369 		len = 0;
370 
371 	ipv6_hdr(skb)->payload_len = htons(len);
372 
373 	if (hw_offload) {
374 		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
375 			return -ENOMEM;
376 
377 		xo = xfrm_offload(skb);
378 		if (!xo)
379 			return -EINVAL;
380 
381 		xo->flags |= XFRM_XMIT;
382 		return 0;
383 	}
384 
385 	err = esp6_output_tail(x, skb, &esp);
386 	if (err)
387 		return err;
388 
389 	secpath_reset(skb);
390 
391 	if (skb_needs_linearize(skb, skb->dev->features) &&
392 	    __skb_linearize(skb))
393 		return -ENOMEM;
394 	return 0;
395 }
396 
397 static const struct net_offload esp6_offload = {
398 	.callbacks = {
399 		.gro_receive = esp6_gro_receive,
400 		.gso_segment = esp6_gso_segment,
401 	},
402 };
403 
404 static const struct xfrm_type_offload esp6_type_offload = {
405 	.owner		= THIS_MODULE,
406 	.proto	     	= IPPROTO_ESP,
407 	.input_tail	= esp6_input_tail,
408 	.xmit		= esp6_xmit,
409 	.encap		= esp6_gso_encap,
410 };
411 
412 static int __init esp6_offload_init(void)
413 {
414 	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
415 		pr_info("%s: can't add xfrm type offload\n", __func__);
416 		return -EAGAIN;
417 	}
418 
419 	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
420 }
421 
422 static void __exit esp6_offload_exit(void)
423 {
424 	xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
425 	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
426 }
427 
428 module_init(esp6_offload_init);
429 module_exit(esp6_offload_exit);
430 MODULE_LICENSE("GPL");
431 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
432 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
433 MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");
434