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
esp6_nexthdr_esp_offset(struct ipv6hdr * ipv6_hdr,int nhlen)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
esp6_gro_receive(struct list_head * head,struct sk_buff * skb)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 xfrm_state_put(x);
90 goto out_reset;
91 }
92 }
93
94 xo->flags |= XFRM_GRO;
95
96 nhoff = esp6_nexthdr_esp_offset(ipv6_hdr(skb), offset);
97 if (!nhoff)
98 goto out;
99
100 IP6CB(skb)->nhoff = nhoff;
101 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
102 XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
103 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
104 XFRM_SPI_SKB_CB(skb)->seq = seq;
105
106 /* We don't need to handle errors from xfrm_input, it does all
107 * the error handling and frees the resources on error. */
108 xfrm_input(skb, IPPROTO_ESP, spi, -2);
109
110 return ERR_PTR(-EINPROGRESS);
111 out_reset:
112 secpath_reset(skb);
113 out:
114 skb_push(skb, offset);
115 NAPI_GRO_CB(skb)->same_flow = 0;
116 NAPI_GRO_CB(skb)->flush = 1;
117
118 return NULL;
119 }
120
esp6_gso_encap(struct xfrm_state * x,struct sk_buff * skb)121 static void esp6_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
122 {
123 struct ip_esp_hdr *esph;
124 struct ipv6hdr *iph = ipv6_hdr(skb);
125 struct xfrm_offload *xo = xfrm_offload(skb);
126 int proto = iph->nexthdr;
127
128 skb_push(skb, -skb_network_offset(skb));
129 esph = ip_esp_hdr(skb);
130 *skb_mac_header(skb) = IPPROTO_ESP;
131
132 esph->spi = x->id.spi;
133 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
134
135 xo->proto = proto;
136 }
137
xfrm6_tunnel_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)138 static struct sk_buff *xfrm6_tunnel_gso_segment(struct xfrm_state *x,
139 struct sk_buff *skb,
140 netdev_features_t features)
141 {
142 __skb_push(skb, skb->mac_len);
143 return skb_mac_gso_segment(skb, features);
144 }
145
xfrm6_transport_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)146 static struct sk_buff *xfrm6_transport_gso_segment(struct xfrm_state *x,
147 struct sk_buff *skb,
148 netdev_features_t features)
149 {
150 const struct net_offload *ops;
151 struct sk_buff *segs = ERR_PTR(-EINVAL);
152 struct xfrm_offload *xo = xfrm_offload(skb);
153
154 skb->transport_header += x->props.header_len;
155 ops = rcu_dereference(inet6_offloads[xo->proto]);
156 if (likely(ops && ops->callbacks.gso_segment))
157 segs = ops->callbacks.gso_segment(skb, features);
158
159 return segs;
160 }
161
xfrm6_outer_mode_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)162 static struct sk_buff *xfrm6_outer_mode_gso_segment(struct xfrm_state *x,
163 struct sk_buff *skb,
164 netdev_features_t features)
165 {
166 switch (x->outer_mode.encap) {
167 case XFRM_MODE_TUNNEL:
168 return xfrm6_tunnel_gso_segment(x, skb, features);
169 case XFRM_MODE_TRANSPORT:
170 return xfrm6_transport_gso_segment(x, skb, features);
171 }
172
173 return ERR_PTR(-EOPNOTSUPP);
174 }
175
esp6_gso_segment(struct sk_buff * skb,netdev_features_t features)176 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
177 netdev_features_t features)
178 {
179 struct xfrm_state *x;
180 struct ip_esp_hdr *esph;
181 struct crypto_aead *aead;
182 netdev_features_t esp_features = features;
183 struct xfrm_offload *xo = xfrm_offload(skb);
184 struct sec_path *sp;
185
186 if (!xo)
187 return ERR_PTR(-EINVAL);
188
189 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
190 return ERR_PTR(-EINVAL);
191
192 sp = skb_sec_path(skb);
193 x = sp->xvec[sp->len - 1];
194 aead = x->data;
195 esph = ip_esp_hdr(skb);
196
197 if (esph->spi != x->id.spi)
198 return ERR_PTR(-EINVAL);
199
200 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
201 return ERR_PTR(-EINVAL);
202
203 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
204
205 skb->encap_hdr_csum = 1;
206
207 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
208 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
209 else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
210 esp_features = features & ~NETIF_F_CSUM_MASK;
211
212 xo->flags |= XFRM_GSO_SEGMENT;
213
214 return xfrm6_outer_mode_gso_segment(x, skb, esp_features);
215 }
216
esp6_input_tail(struct xfrm_state * x,struct sk_buff * skb)217 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
218 {
219 struct crypto_aead *aead = x->data;
220 struct xfrm_offload *xo = xfrm_offload(skb);
221
222 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
223 return -EINVAL;
224
225 if (!(xo->flags & CRYPTO_DONE))
226 skb->ip_summed = CHECKSUM_NONE;
227
228 return esp6_input_done2(skb, 0);
229 }
230
esp6_xmit(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)231 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
232 {
233 int len;
234 int err;
235 int alen;
236 int blksize;
237 struct xfrm_offload *xo;
238 struct ip_esp_hdr *esph;
239 struct crypto_aead *aead;
240 struct esp_info esp;
241 bool hw_offload = true;
242 __u32 seq;
243
244 esp.inplace = true;
245
246 xo = xfrm_offload(skb);
247
248 if (!xo)
249 return -EINVAL;
250
251 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
252 xo->flags |= CRYPTO_FALLBACK;
253 hw_offload = false;
254 }
255
256 esp.proto = xo->proto;
257
258 /* skb is pure payload to encrypt */
259
260 aead = x->data;
261 alen = crypto_aead_authsize(aead);
262
263 esp.tfclen = 0;
264 /* XXX: Add support for tfc padding here. */
265
266 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
267 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
268 esp.plen = esp.clen - skb->len - esp.tfclen;
269 esp.tailen = esp.tfclen + esp.plen + alen;
270
271 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
272 esp.nfrags = esp6_output_head(x, skb, &esp);
273 if (esp.nfrags < 0)
274 return esp.nfrags;
275 }
276
277 seq = xo->seq.low;
278
279 esph = ip_esp_hdr(skb);
280 esph->spi = x->id.spi;
281
282 skb_push(skb, -skb_network_offset(skb));
283
284 if (xo->flags & XFRM_GSO_SEGMENT) {
285 esph->seq_no = htonl(seq);
286
287 if (!skb_is_gso(skb))
288 xo->seq.low++;
289 else
290 xo->seq.low += skb_shinfo(skb)->gso_segs;
291 }
292
293 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
294
295 len = skb->len - sizeof(struct ipv6hdr);
296 if (len > IPV6_MAXPLEN)
297 len = 0;
298
299 ipv6_hdr(skb)->payload_len = htons(len);
300
301 if (hw_offload)
302 return 0;
303
304 err = esp6_output_tail(x, skb, &esp);
305 if (err)
306 return err;
307
308 secpath_reset(skb);
309
310 return 0;
311 }
312
313 static const struct net_offload esp6_offload = {
314 .callbacks = {
315 .gro_receive = esp6_gro_receive,
316 .gso_segment = esp6_gso_segment,
317 },
318 };
319
320 static const struct xfrm_type_offload esp6_type_offload = {
321 .description = "ESP6 OFFLOAD",
322 .owner = THIS_MODULE,
323 .proto = IPPROTO_ESP,
324 .input_tail = esp6_input_tail,
325 .xmit = esp6_xmit,
326 .encap = esp6_gso_encap,
327 };
328
esp6_offload_init(void)329 static int __init esp6_offload_init(void)
330 {
331 if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
332 pr_info("%s: can't add xfrm type offload\n", __func__);
333 return -EAGAIN;
334 }
335
336 return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
337 }
338
esp6_offload_exit(void)339 static void __exit esp6_offload_exit(void)
340 {
341 xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6);
342 inet6_del_offload(&esp6_offload, IPPROTO_ESP);
343 }
344
345 module_init(esp6_offload_init);
346 module_exit(esp6_offload_exit);
347 MODULE_LICENSE("GPL");
348 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
349 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
350