xref: /openbmc/linux/net/ipv6/esp6_offload.c (revision 31d5f934) 
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/ip.h>
21 #include <net/xfrm.h>
22 #include <net/esp.h>
23 #include <linux/scatterlist.h>
24 #include <linux/kernel.h>
25 #include <linux/slab.h>
26 #include <linux/spinlock.h>
27 #include <net/ip6_route.h>
28 #include <net/ipv6.h>
29 #include <linux/icmpv6.h>
30 
31 static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
32 {
33 	int off = sizeof(struct ipv6hdr);
34 	struct ipv6_opt_hdr *exthdr;
35 
36 	if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
37 		return offsetof(struct ipv6hdr, nexthdr);
38 
39 	while (off < nhlen) {
40 		exthdr = (void *)ipv6_hdr + off;
41 		if (exthdr->nexthdr == NEXTHDR_ESP)
42 			return off;
43 
44 		off += ipv6_optlen(exthdr);
45 	}
46 
47 	return 0;
48 }
49 
50 static struct sk_buff *esp6_gro_receive(struct list_head *head,
51 					struct sk_buff *skb)
52 {
53 	int offset = skb_gro_offset(skb);
54 	struct xfrm_offload *xo;
55 	struct xfrm_state *x;
56 	__be32 seq;
57 	__be32 spi;
58 	int nhoff;
59 
60 	if (!pskb_pull(skb, offset))
61 		return NULL;
62 
63 	if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
64 		goto out;
65 
66 	xo = xfrm_offload(skb);
67 	if (!xo || !(xo->flags & CRYPTO_DONE)) {
68 		struct sec_path *sp = secpath_set(skb);
69 
70 		if (!sp)
71 			goto out;
72 
73 		if (sp->len == XFRM_MAX_DEPTH)
74 			goto out_reset;
75 
76 		x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
77 				      (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
78 				      spi, IPPROTO_ESP, AF_INET6);
79 		if (!x)
80 			goto out_reset;
81 
82 		skb->mark = xfrm_smark_get(skb->mark, x);
83 
84 		sp->xvec[sp->len++] = x;
85 		sp->olen++;
86 
87 		xo = xfrm_offload(skb);
88 		if (!xo)
89 			goto out_reset;
90 	}
91 
92 	xo->flags |= XFRM_GRO;
93 
94 	nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
95 	if (!nhoff)
96 		goto out;
97 
98 	IP6CB(skb)->nhoff = nhoff;
99 	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
100 	XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
101 	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
102 	XFRM_SPI_SKB_CB(skb)->seq = seq;
103 
104 	/* We don't need to handle errors from xfrm_input, it does all
105 	 * the error handling and frees the resources on error. */
106 	xfrm_input(skb, IPPROTO_ESP, spi, -2);
107 
108 	return ERR_PTR(-EINPROGRESS);
109 out_reset:
110 	secpath_reset(skb);
111 out:
112 	skb_push(skb, offset);
113 	NAPI_GRO_CB(skb)->same_flow = 0;
114 	NAPI_GRO_CB(skb)->flush = 1;
115 
116 	return NULL;
117 }
118 
119 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
120 {
121 	struct ip_esp_hdr *esph;
122 	struct ipv6hdr *iph = ipv6_hdr(skb);
123 	struct xfrm_offload *xo = xfrm_offload(skb);
124 	u8 proto = iph->nexthdr;
125 
126 	skb_push(skb, -skb_network_offset(skb));
127 
128 	if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
129 		__be16 frag;
130 
131 		ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &proto, &frag);
132 	}
133 
134 	esph = ip_esp_hdr(skb);
135 	*skb_mac_header(skb) = IPPROTO_ESP;
136 
137 	esph->spi = x->id.spi;
138 	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
139 
140 	xo->proto = proto;
141 }
142 
143 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
144 						struct sk_buff *skb,
145 						netdev_features_t features)
146 {
147 	__be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
148 						      : htons(ETH_P_IPV6);
149 
150 	return skb_eth_gso_segment(skb, features, type);
151 }
152 
153 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
154 						   struct sk_buff *skb,
155 						   netdev_features_t features)
156 {
157 	const struct net_offload *ops;
158 	struct sk_buff *segs = ERR_PTR(-EINVAL);
159 	struct xfrm_offload *xo = xfrm_offload(skb);
160 
161 	skb->transport_header += x->props.header_len;
162 	ops = rcu_dereference(inet6_offloads[xo->proto]);
163 	if (likely(ops && ops->callbacks.gso_segment))
164 		segs = ops->callbacks.gso_segment(skb, features);
165 
166 	return segs;
167 }
168 
169 static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
170 					      struct sk_buff *skb,
171 					      netdev_features_t features)
172 {
173 	struct xfrm_offload *xo = xfrm_offload(skb);
174 	struct sk_buff *segs = ERR_PTR(-EINVAL);
175 	const struct net_offload *ops;
176 	u8 proto = xo->proto;
177 
178 	skb->transport_header += x->props.header_len;
179 
180 	if (x->sel.family != AF_INET6) {
181 		skb->transport_header -=
182 			(sizeof(struct ipv6hdr) - sizeof(struct iphdr));
183 
184 		if (proto == IPPROTO_BEETPH) {
185 			struct ip_beet_phdr *ph =
186 				(struct ip_beet_phdr *)skb->data;
187 
188 			skb->transport_header += ph->hdrlen * 8;
189 			proto = ph->nexthdr;
190 		} else {
191 			skb->transport_header -= IPV4_BEET_PHMAXLEN;
192 		}
193 
194 		if (proto == IPPROTO_TCP)
195 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
196 	} else {
197 		__be16 frag;
198 
199 		skb->transport_header +=
200 			ipv6_skip_exthdr(skb, 0, &proto, &frag);
201 	}
202 
203 	if (proto == IPPROTO_IPIP)
204 		skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
205 
206 	__skb_pull(skb, skb_transport_offset(skb));
207 	ops = rcu_dereference(inet6_offloads[proto]);
208 	if (likely(ops && ops->callbacks.gso_segment))
209 		segs = ops->callbacks.gso_segment(skb, features);
210 
211 	return segs;
212 }
213 
214 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
215 						    struct sk_buff *skb,
216 						    netdev_features_t features)
217 {
218 	switch (x->outer_mode.encap) {
219 	case XFRM_MODE_TUNNEL:
220 		return xfrm6_tunnel_gso_segment(x, skb, features);
221 	case XFRM_MODE_TRANSPORT:
222 		return xfrm6_transport_gso_segment(x, skb, features);
223 	case XFRM_MODE_BEET:
224 		return xfrm6_beet_gso_segment(x, skb, features);
225 	}
226 
227 	return ERR_PTR(-EOPNOTSUPP);
228 }
229 
230 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
231 				        netdev_features_t features)
232 {
233 	struct xfrm_state *x;
234 	struct ip_esp_hdr *esph;
235 	struct crypto_aead *aead;
236 	netdev_features_t esp_features = features;
237 	struct xfrm_offload *xo = xfrm_offload(skb);
238 	struct sec_path *sp;
239 
240 	if (!xo)
241 		return ERR_PTR(-EINVAL);
242 
243 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
244 		return ERR_PTR(-EINVAL);
245 
246 	sp = skb_sec_path(skb);
247 	x = sp->xvec[sp->len - 1];
248 	aead = x->data;
249 	esph = ip_esp_hdr(skb);
250 
251 	if (esph->spi != x->id.spi)
252 		return ERR_PTR(-EINVAL);
253 
254 	if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
255 		return ERR_PTR(-EINVAL);
256 
257 	__skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
258 
259 	skb->encap_hdr_csum = 1;
260 
261 	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
262 		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
263 					    NETIF_F_SCTP_CRC);
264 	else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
265 		esp_features = features & ~(NETIF_F_CSUM_MASK |
266 					    NETIF_F_SCTP_CRC);
267 
268 	xo->flags |= XFRM_GSO_SEGMENT;
269 
270 	return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
271 }
272 
273 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
274 {
275 	struct crypto_aead *aead = x->data;
276 	struct xfrm_offload *xo = xfrm_offload(skb);
277 
278 	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
279 		return -EINVAL;
280 
281 	if (!(xo->flags & CRYPTO_DONE))
282 		skb->ip_summed = CHECKSUM_NONE;
283 
284 	return esp6_input_done2(skb, 0);
285 }
286 
287 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb,  netdev_features_t features)
288 {
289 	int len;
290 	int err;
291 	int alen;
292 	int blksize;
293 	struct xfrm_offload *xo;
294 	struct crypto_aead *aead;
295 	struct esp_info esp;
296 	bool hw_offload = true;
297 	__u32 seq;
298 
299 	esp.inplace = true;
300 
301 	xo = xfrm_offload(skb);
302 
303 	if (!xo)
304 		return -EINVAL;
305 
306 	if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
307 		xo->flags |= CRYPTO_FALLBACK;
308 		hw_offload = false;
309 	}
310 
311 	esp.proto = xo->proto;
312 
313 	/* skb is pure payload to encrypt */
314 
315 	aead = x->data;
316 	alen = crypto_aead_authsize(aead);
317 
318 	esp.tfclen = 0;
319 	/* XXX: Add support for tfc padding here. */
320 
321 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
322 	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
323 	esp.plen = esp.clen - skb->len - esp.tfclen;
324 	esp.tailen = esp.tfclen + esp.plen + alen;
325 
326 	if (!hw_offload || !skb_is_gso(skb)) {
327 		esp.nfrags = esp6_output_head(x, skb, &esp);
328 		if (esp.nfrags < 0)
329 			return esp.nfrags;
330 	}
331 
332 	seq = xo->seq.low;
333 
334 	esp.esph = ip_esp_hdr(skb);
335 	esp.esph->spi = x->id.spi;
336 
337 	skb_push(skb, -skb_network_offset(skb));
338 
339 	if (xo->flags & XFRM_GSO_SEGMENT) {
340 		esp.esph->seq_no = htonl(seq);
341 
342 		if (!skb_is_gso(skb))
343 			xo->seq.low++;
344 		else
345 			xo->seq.low += skb_shinfo(skb)->gso_segs;
346 	}
347 
348 	if (xo->seq.low < seq)
349 		xo->seq.hi++;
350 
351 	esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
352 
353 	len = skb->len - sizeof(struct ipv6hdr);
354 	if (len > IPV6_MAXPLEN)
355 		len = 0;
356 
357 	ipv6_hdr(skb)->payload_len = htons(len);
358 
359 	if (hw_offload) {
360 		if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
361 			return -ENOMEM;
362 
363 		xo = xfrm_offload(skb);
364 		if (!xo)
365 			return -EINVAL;
366 
367 		xo->flags |= XFRM_XMIT;
368 		return 0;
369 	}
370 
371 	err = esp6_output_tail(x, skb, &esp);
372 	if (err)
373 		return err;
374 
375 	secpath_reset(skb);
376 
377 	return 0;
378 }
379 
380 static const struct net_offload esp6_offload = {
381 	.callbacks = {
382 		.gro_receive = esp6_gro_receive,
383 		.gso_segment = esp6_gso_segment,
384 	},
385 };
386 
387 static const struct xfrm_type_offload esp6_type_offload = {
388 	.owner		= THIS_MODULE,
389 	.proto	     	= IPPROTO_ESP,
390 	.input_tail	= esp6_input_tail,
391 	.xmit		= esp6_xmit,
392 	.encap		= esp6_gso_encap,
393 };
394 
395 static int __init esp6_offload_init(void)
396 {
397 	if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
398 		pr_info("%s: can't add xfrm type offload\n", __func__);
399 		return -EAGAIN;
400 	}
401 
402 	return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
403 }
404 
405 static void __exit esp6_offload_exit(void)
406 {
407 	xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
408 	inet6_del_offload(&esp6_offload, IPPROTO_ESP);
409 }
410 
411 module_init(esp6_offload_init);
412 module_exit(esp6_offload_exit);
413 MODULE_LICENSE("GPL");
414 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
415 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
416 MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");
417