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/ip.h>
20 #include <net/xfrm.h>
21 #include <net/esp.h>
22 #include <linux/scatterlist.h>
23 #include <linux/kernel.h>
24 #include <linux/slab.h>
25 #include <linux/spinlock.h>
26 #include <net/ip6_route.h>
27 #include <net/ipv6.h>
28 #include <linux/icmpv6.h>
29
30 static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
31 {
32 int off = sizeof(struct ipv6hdr);
33 struct ipv6_opt_hdr *exthdr;
34
35 if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
36 return offsetof(struct ipv6hdr, nexthdr);
37
38 while (off < nhlen) {
39 exthdr = (void *)ipv6_hdr + off;
40 if (exthdr->nexthdr == NEXTHDR_ESP)
41 return off;
42
43 off += ipv6_optlen(exthdr);
44 }
45
46 return 0;
47 }
48
49 static struct sk_buff *esp6_gro_receive(struct list_head *head,
50 struct sk_buff *skb)
51 {
52 int offset = skb_gro_offset(skb);
53 struct xfrm_offload *xo;
54 struct xfrm_state *x;
55 __be32 seq;
56 __be32 spi;
57 int nhoff;
58 int err;
59
60 if (!pskb_pull(skb, offset))
61 return NULL;
62
63 if ((err = 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 __skb_push(skb, skb->mac_len);
148 return skb_mac_gso_segment(skb, features);
149 }
150
151 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
152 struct sk_buff *skb,
153 netdev_features_t features)
154 {
155 const struct net_offload *ops;
156 struct sk_buff *segs = ERR_PTR(-EINVAL);
157 struct xfrm_offload *xo = xfrm_offload(skb);
158
159 skb->transport_header += x->props.header_len;
160 ops = rcu_dereference(inet6_offloads[xo->proto]);
161 if (likely(ops && ops->callbacks.gso_segment))
162 segs = ops->callbacks.gso_segment(skb, features);
163
164 return segs;
165 }
166
167 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
168 struct sk_buff *skb,
169 netdev_features_t features)
170 {
171 switch (x->outer_mode.encap) {
172 case XFRM_MODE_TUNNEL:
173 return xfrm6_tunnel_gso_segment(x, skb, features);
174 case XFRM_MODE_TRANSPORT:
175 return xfrm6_transport_gso_segment(x, skb, features);
176 }
177
178 return ERR_PTR(-EOPNOTSUPP);
179 }
180
181 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
182 netdev_features_t features)
183 {
184 struct xfrm_state *x;
185 struct ip_esp_hdr *esph;
186 struct crypto_aead *aead;
187 netdev_features_t esp_features = features;
188 struct xfrm_offload *xo = xfrm_offload(skb);
189 struct sec_path *sp;
190
191 if (!xo)
192 return ERR_PTR(-EINVAL);
193
194 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
195 return ERR_PTR(-EINVAL);
196
197 sp = skb_sec_path(skb);
198 x = sp->xvec[sp->len - 1];
199 aead = x->data;
200 esph = ip_esp_hdr(skb);
201
202 if (esph->spi != x->id.spi)
203 return ERR_PTR(-EINVAL);
204
205 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
206 return ERR_PTR(-EINVAL);
207
208 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
209
210 skb->encap_hdr_csum = 1;
211
212 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
213 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
214 else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
215 esp_features = features & ~NETIF_F_CSUM_MASK;
216
217 xo->flags |= XFRM_GSO_SEGMENT;
218
219 return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
220 }
221
222 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
223 {
224 struct crypto_aead *aead = x->data;
225 struct xfrm_offload *xo = xfrm_offload(skb);
226
227 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
228 return -EINVAL;
229
230 if (!(xo->flags & CRYPTO_DONE))
231 skb->ip_summed = CHECKSUM_NONE;
232
233 return esp6_input_done2(skb, 0);
234 }
235
236 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
237 {
238 int len;
239 int err;
240 int alen;
241 int blksize;
242 struct xfrm_offload *xo;
243 struct ip_esp_hdr *esph;
244 struct crypto_aead *aead;
245 struct esp_info esp;
246 bool hw_offload = true;
247 __u32 seq;
248
249 esp.inplace = true;
250
251 xo = xfrm_offload(skb);
252
253 if (!xo)
254 return -EINVAL;
255
256 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
257 xo->flags |= CRYPTO_FALLBACK;
258 hw_offload = false;
259 }
260
261 esp.proto = xo->proto;
262
263 /* skb is pure payload to encrypt */
264
265 aead = x->data;
266 alen = crypto_aead_authsize(aead);
267
268 esp.tfclen = 0;
269 /* XXX: Add support for tfc padding here. */
270
271 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
272 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
273 esp.plen = esp.clen - skb->len - esp.tfclen;
274 esp.tailen = esp.tfclen + esp.plen + alen;
275
276 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
277 esp.nfrags = esp6_output_head(x, skb, &esp);
278 if (esp.nfrags < 0)
279 return esp.nfrags;
280 }
281
282 seq = xo->seq.low;
283
284 esph = ip_esp_hdr(skb);
285 esph->spi = x->id.spi;
286
287 skb_push(skb, -skb_network_offset(skb));
288
289 if (xo->flags & XFRM_GSO_SEGMENT) {
290 esph->seq_no = htonl(seq);
291
292 if (!skb_is_gso(skb))
293 xo->seq.low++;
294 else
295 xo->seq.low += skb_shinfo(skb)->gso_segs;
296 }
297
298 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
299
300 len = skb->len - sizeof(struct ipv6hdr);
301 if (len > IPV6_MAXPLEN)
302 len = 0;
303
304 ipv6_hdr(skb)->payload_len = htons(len);
305
306 if (hw_offload)
307 return 0;
308
309 err = esp6_output_tail(x, skb, &esp);
310 if (err)
311 return err;
312
313 secpath_reset(skb);
314
315 return 0;
316 }
317
318 static const struct net_offload esp6_offload = {
319 .callbacks = {
320 .gro_receive = esp6_gro_receive,
321 .gso_segment = esp6_gso_segment,
322 },
323 };
324
325 static const struct xfrm_type_offload esp6_type_offload = {
326 .description = "ESP6 OFFLOAD",
327 .owner = THIS_MODULE,
328 .proto = IPPROTO_ESP,
329 .input_tail = esp6_input_tail,
330 .xmit = esp6_xmit,
331 .encap = esp6_gso_encap,
332 };
333
334 static int __init esp6_offload_init(void)
335 {
336 if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
337 pr_info("%s: can't add xfrm type offload\n", __func__);
338 return -EAGAIN;
339 }
340
341 return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
342 }
343
344 static void __exit esp6_offload_exit(void)
345 {
346 xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
347 inet6_del_offload(&esp6_offload, IPPROTO_ESP);
348 }
349
350 module_init(esp6_offload_init);
351 module_exit(esp6_offload_exit);
352 MODULE_LICENSE("GPL");
353 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
354 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
355
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