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
32static __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
53static 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, len: offset))
68 return NULL;
69
70 if (xfrm_parse_spi(skb, IPPROTO_ESP, spi: &spi, seq: &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(net: dev_net(dev: skb->dev), mark: skb->mark,
84 daddr: (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
85 spi, IPPROTO_ESP, AF_INET6);
86 if (!x)
87 goto out_reset;
88
89 skb->mark = xfrm_smark_get(mark: skb->mark, x);
90
91 sp->xvec[sp->len++] = x;
92 sp->olen++;
93
94 xo = xfrm_offload(skb);
95 if (!xo)
96 goto out_reset;
97 }
98
99 xo->flags |= XFRM_GRO;
100
101 nhoff = esp6_nexthdr_esp_offset(ipv6_hdr: ipv6_hdr(skb), nhlen: offset);
102 if (!nhoff)
103 goto out;
104
105 IP6CB(skb)->nhoff = nhoff;
106 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
107 XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
108 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
109 XFRM_SPI_SKB_CB(skb)->seq = seq;
110
111 /* We don't need to handle errors from xfrm_input, it does all
112 * the error handling and frees the resources on error. */
113 xfrm_input(skb, IPPROTO_ESP, spi, encap_type);
114
115 return ERR_PTR(error: -EINPROGRESS);
116out_reset:
117 secpath_reset(skb);
118out:
119 skb_push(skb, len: offset);
120 NAPI_GRO_CB(skb)->same_flow = 0;
121 NAPI_GRO_CB(skb)->flush = 1;
122
123 return NULL;
124}
125
126static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
127{
128 struct ip_esp_hdr *esph;
129 struct ipv6hdr *iph = ipv6_hdr(skb);
130 struct xfrm_offload *xo = xfrm_offload(skb);
131 u8 proto = iph->nexthdr;
132
133 skb_push(skb, len: -skb_network_offset(skb));
134
135 if (x->outer_mode.encap == XFRM_MODE_TRANSPORT) {
136 __be16 frag;
137
138 ipv6_skip_exthdr(skb, start: sizeof(struct ipv6hdr), nexthdrp: &proto, frag_offp: &frag);
139 }
140
141 esph = ip_esp_hdr(skb);
142 *skb_mac_header(skb) = IPPROTO_ESP;
143
144 esph->spi = x->id.spi;
145 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
146
147 xo->proto = proto;
148}
149
150static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
151 struct sk_buff *skb,
152 netdev_features_t features)
153{
154 __be16 type = x->inner_mode.family == AF_INET ? htons(ETH_P_IP)
155 : htons(ETH_P_IPV6);
156
157 return skb_eth_gso_segment(skb, features, type);
158}
159
160static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
161 struct sk_buff *skb,
162 netdev_features_t features)
163{
164 const struct net_offload *ops;
165 struct sk_buff *segs = ERR_PTR(error: -EINVAL);
166 struct xfrm_offload *xo = xfrm_offload(skb);
167
168 skb->transport_header += x->props.header_len;
169 ops = rcu_dereference(inet6_offloads[xo->proto]);
170 if (likely(ops && ops->callbacks.gso_segment))
171 segs = ops->callbacks.gso_segment(skb, features);
172
173 return segs;
174}
175
176static struct sk_buff *xfrm6_beet_gso_segment(struct xfrm_state *x,
177 struct sk_buff *skb,
178 netdev_features_t features)
179{
180 struct xfrm_offload *xo = xfrm_offload(skb);
181 struct sk_buff *segs = ERR_PTR(error: -EINVAL);
182 const struct net_offload *ops;
183 u8 proto = xo->proto;
184
185 skb->transport_header += x->props.header_len;
186
187 if (x->sel.family != AF_INET6) {
188 skb->transport_header -=
189 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
190
191 if (proto == IPPROTO_BEETPH) {
192 struct ip_beet_phdr *ph =
193 (struct ip_beet_phdr *)skb->data;
194
195 skb->transport_header += ph->hdrlen * 8;
196 proto = ph->nexthdr;
197 } else {
198 skb->transport_header -= IPV4_BEET_PHMAXLEN;
199 }
200
201 if (proto == IPPROTO_TCP)
202 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV6;
203 } else {
204 __be16 frag;
205
206 skb->transport_header +=
207 ipv6_skip_exthdr(skb, start: 0, nexthdrp: &proto, frag_offp: &frag);
208 }
209
210 if (proto == IPPROTO_IPIP)
211 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
212
213 __skb_pull(skb, len: skb_transport_offset(skb));
214 ops = rcu_dereference(inet6_offloads[proto]);
215 if (likely(ops && ops->callbacks.gso_segment))
216 segs = ops->callbacks.gso_segment(skb, features);
217
218 return segs;
219}
220
221static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
222 struct sk_buff *skb,
223 netdev_features_t features)
224{
225 switch (x->outer_mode.encap) {
226 case XFRM_MODE_TUNNEL:
227 return xfrm6_tunnel_gso_segment(x, skb, features);
228 case XFRM_MODE_TRANSPORT:
229 return xfrm6_transport_gso_segment(x, skb, features);
230 case XFRM_MODE_BEET:
231 return xfrm6_beet_gso_segment(x, skb, features);
232 }
233
234 return ERR_PTR(error: -EOPNOTSUPP);
235}
236
237static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
238 netdev_features_t features)
239{
240 struct xfrm_state *x;
241 struct ip_esp_hdr *esph;
242 struct crypto_aead *aead;
243 netdev_features_t esp_features = features;
244 struct xfrm_offload *xo = xfrm_offload(skb);
245 struct sec_path *sp;
246
247 if (!xo)
248 return ERR_PTR(error: -EINVAL);
249
250 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
251 return ERR_PTR(error: -EINVAL);
252
253 sp = skb_sec_path(skb);
254 x = sp->xvec[sp->len - 1];
255 aead = x->data;
256 esph = ip_esp_hdr(skb);
257
258 if (esph->spi != x->id.spi)
259 return ERR_PTR(error: -EINVAL);
260
261 if (!pskb_may_pull(skb, len: sizeof(*esph) + crypto_aead_ivsize(tfm: aead)))
262 return ERR_PTR(error: -EINVAL);
263
264 __skb_pull(skb, len: sizeof(*esph) + crypto_aead_ivsize(tfm: aead));
265
266 skb->encap_hdr_csum = 1;
267
268 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
269 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
270 NETIF_F_SCTP_CRC);
271 else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
272 esp_features = features & ~(NETIF_F_CSUM_MASK |
273 NETIF_F_SCTP_CRC);
274
275 xo->flags |= XFRM_GSO_SEGMENT;
276
277 return xfrm6_outer_mode_gso_segment(x, skb, features: esp_features);
278}
279
280static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
281{
282 struct crypto_aead *aead = x->data;
283 struct xfrm_offload *xo = xfrm_offload(skb);
284
285 if (!pskb_may_pull(skb, len: sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(tfm: aead)))
286 return -EINVAL;
287
288 if (!(xo->flags & CRYPTO_DONE))
289 skb->ip_summed = CHECKSUM_NONE;
290
291 return esp6_input_done2(skb, err: 0);
292}
293
294static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
295{
296 int len;
297 int err;
298 int alen;
299 int blksize;
300 struct xfrm_offload *xo;
301 struct crypto_aead *aead;
302 struct esp_info esp;
303 bool hw_offload = true;
304 __u32 seq;
305
306 esp.inplace = true;
307
308 xo = xfrm_offload(skb);
309
310 if (!xo)
311 return -EINVAL;
312
313 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
314 xo->flags |= CRYPTO_FALLBACK;
315 hw_offload = false;
316 }
317
318 esp.proto = xo->proto;
319
320 /* skb is pure payload to encrypt */
321
322 aead = x->data;
323 alen = crypto_aead_authsize(tfm: aead);
324
325 esp.tfclen = 0;
326 /* XXX: Add support for tfc padding here. */
327
328 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
329 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
330 esp.plen = esp.clen - skb->len - esp.tfclen;
331 esp.tailen = esp.tfclen + esp.plen + alen;
332
333 if (!hw_offload || !skb_is_gso(skb)) {
334 esp.nfrags = esp6_output_head(x, skb, esp: &esp);
335 if (esp.nfrags < 0)
336 return esp.nfrags;
337 }
338
339 seq = xo->seq.low;
340
341 esp.esph = ip_esp_hdr(skb);
342 esp.esph->spi = x->id.spi;
343
344 skb_push(skb, len: -skb_network_offset(skb));
345
346 if (xo->flags & XFRM_GSO_SEGMENT) {
347 esp.esph->seq_no = htonl(seq);
348
349 if (!skb_is_gso(skb))
350 xo->seq.low++;
351 else
352 xo->seq.low += skb_shinfo(skb)->gso_segs;
353 }
354
355 if (xo->seq.low < seq)
356 xo->seq.hi++;
357
358 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
359
360 len = skb->len - sizeof(struct ipv6hdr);
361 if (len > IPV6_MAXPLEN)
362 len = 0;
363
364 ipv6_hdr(skb)->payload_len = htons(len);
365
366 if (hw_offload) {
367 if (!skb_ext_add(skb, id: SKB_EXT_SEC_PATH))
368 return -ENOMEM;
369
370 xo = xfrm_offload(skb);
371 if (!xo)
372 return -EINVAL;
373
374 xo->flags |= XFRM_XMIT;
375 return 0;
376 }
377
378 err = esp6_output_tail(x, skb, esp: &esp);
379 if (err)
380 return err;
381
382 secpath_reset(skb);
383
384 if (skb_needs_linearize(skb, features: skb->dev->features) &&
385 __skb_linearize(skb))
386 return -ENOMEM;
387 return 0;
388}
389
390static const struct net_offload esp6_offload = {
391 .callbacks = {
392 .gro_receive = esp6_gro_receive,
393 .gso_segment = esp6_gso_segment,
394 },
395};
396
397static const struct xfrm_type_offload esp6_type_offload = {
398 .owner = THIS_MODULE,
399 .proto = IPPROTO_ESP,
400 .input_tail = esp6_input_tail,
401 .xmit = esp6_xmit,
402 .encap = esp6_gso_encap,
403};
404
405static int __init esp6_offload_init(void)
406{
407 if (xfrm_register_type_offload(type: &esp6_type_offload, AF_INET6) < 0) {
408 pr_info("%s: can't add xfrm type offload\n", __func__);
409 return -EAGAIN;
410 }
411
412 return inet6_add_offload(prot: &esp6_offload, IPPROTO_ESP);
413}
414
415static void __exit esp6_offload_exit(void)
416{
417 xfrm_unregister_type_offload(type: &esp6_type_offload, AF_INET6);
418 inet6_del_offload(prot: &esp6_offload, IPPROTO_ESP);
419}
420
421module_init(esp6_offload_init);
422module_exit(esp6_offload_exit);
423MODULE_LICENSE("GPL");
424MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
425MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
426MODULE_DESCRIPTION("IPV6 GSO/GRO offload support");
427

source code of linux/net/ipv6/esp6_offload.c