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