1 /*
2 * IPV6 GSO/GRO offload support
3 * Linux INET implementation
4 *
5 * Copyright (C) 2016 secunet Security Networks AG
6 * Author: Steffen Klassert <steffen.klassert@secunet.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * ESP GRO support
13 */
14
15 #include <linux/skbuff.h>
16 #include <linux/init.h>
17 #include <net/protocol.h>
18 #include <crypto/aead.h>
19 #include <crypto/authenc.h>
20 #include <linux/err.h>
21 #include <linux/module.h>
22 #include <net/ip.h>
23 #include <net/xfrm.h>
24 #include <net/esp.h>
25 #include <linux/scatterlist.h>
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <net/ip6_route.h>
30 #include <net/ipv6.h>
31 #include <linux/icmpv6.h>
32
esp6_nexthdr_esp_offset(struct ipv6hdr * ipv6_hdr,int nhlen)33 static __u16 esp6_nexthdr_esp_offset(struct ipv6hdr *ipv6_hdr, int nhlen)
34 {
35 int off = sizeof(struct ipv6hdr);
36 struct ipv6_opt_hdr *exthdr;
37
38 if (likely(ipv6_hdr->nexthdr == NEXTHDR_ESP))
39 return offsetof(struct ipv6hdr, nexthdr);
40
41 while (off < nhlen) {
42 exthdr = (void *)ipv6_hdr + off;
43 if (exthdr->nexthdr == NEXTHDR_ESP)
44 return off;
45
46 off += ipv6_optlen(exthdr);
47 }
48
49 return 0;
50 }
51
esp6_gro_receive(struct sk_buff ** head,struct sk_buff * skb)52 static struct sk_buff **esp6_gro_receive(struct sk_buff **head,
53 struct sk_buff *skb)
54 {
55 int offset = skb_gro_offset(skb);
56 struct xfrm_offload *xo;
57 struct xfrm_state *x;
58 __be32 seq;
59 __be32 spi;
60 int nhoff;
61 int err;
62
63 if (!pskb_pull(skb, offset))
64 return NULL;
65
66 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
67 goto out;
68
69 xo = xfrm_offload(skb);
70 if (!xo || !(xo->flags & CRYPTO_DONE)) {
71 err = secpath_set(skb);
72 if (err)
73 goto out;
74
75 if (skb->sp->len == XFRM_MAX_DEPTH)
76 goto out;
77
78 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
79 (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
80 spi, IPPROTO_ESP, AF_INET6);
81 if (!x)
82 goto out;
83
84 skb->sp->xvec[skb->sp->len++] = x;
85 skb->sp->olen++;
86
87 xo = xfrm_offload(skb);
88 if (!xo) {
89 xfrm_state_put(x);
90 goto out;
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:
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
esp6_gso_encap(struct xfrm_state * x,struct sk_buff * skb)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 int proto = iph->nexthdr;
125
126 skb_push(skb, -skb_network_offset(skb));
127 esph = ip_esp_hdr(skb);
128 *skb_mac_header(skb) = IPPROTO_ESP;
129
130 esph->spi = x->id.spi;
131 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
132
133 xo->proto = proto;
134 }
135
esp6_gso_segment(struct sk_buff * skb,netdev_features_t features)136 static struct sk_buff *esp6_gso_segment(struct sk_buff *skb,
137 netdev_features_t features)
138 {
139 __u32 seq;
140 int err = 0;
141 struct sk_buff *skb2;
142 struct xfrm_state *x;
143 struct ip_esp_hdr *esph;
144 struct crypto_aead *aead;
145 struct sk_buff *segs = ERR_PTR(-EINVAL);
146 netdev_features_t esp_features = features;
147 struct xfrm_offload *xo = xfrm_offload(skb);
148
149 if (!xo)
150 goto out;
151
152 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
153 goto out;
154
155 seq = xo->seq.low;
156
157 x = skb->sp->xvec[skb->sp->len - 1];
158 aead = x->data;
159 esph = ip_esp_hdr(skb);
160
161 if (esph->spi != x->id.spi)
162 goto out;
163
164 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
165 goto out;
166
167 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
168
169 skb->encap_hdr_csum = 1;
170
171 if (!(features & NETIF_F_HW_ESP))
172 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
173
174 segs = x->outer_mode->gso_segment(x, skb, esp_features);
175 if (IS_ERR_OR_NULL(segs))
176 goto out;
177
178 __skb_pull(skb, skb->data - skb_mac_header(skb));
179
180 skb2 = segs;
181 do {
182 struct sk_buff *nskb = skb2->next;
183
184 xo = xfrm_offload(skb2);
185 xo->flags |= XFRM_GSO_SEGMENT;
186 xo->seq.low = seq;
187 xo->seq.hi = xfrm_replay_seqhi(x, seq);
188
189 if(!(features & NETIF_F_HW_ESP))
190 xo->flags |= CRYPTO_FALLBACK;
191
192 x->outer_mode->xmit(x, skb2);
193
194 err = x->type_offload->xmit(x, skb2, esp_features);
195 if (err) {
196 kfree_skb_list(segs);
197 return ERR_PTR(err);
198 }
199
200 if (!skb_is_gso(skb2))
201 seq++;
202 else
203 seq += skb_shinfo(skb2)->gso_segs;
204
205 skb_push(skb2, skb2->mac_len);
206 skb2 = nskb;
207 } while (skb2);
208
209 out:
210 return segs;
211 }
212
esp6_input_tail(struct xfrm_state * x,struct sk_buff * skb)213 static int esp6_input_tail(struct xfrm_state *x, struct sk_buff *skb)
214 {
215 struct crypto_aead *aead = x->data;
216 struct xfrm_offload *xo = xfrm_offload(skb);
217
218 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
219 return -EINVAL;
220
221 if (!(xo->flags & CRYPTO_DONE))
222 skb->ip_summed = CHECKSUM_NONE;
223
224 return esp6_input_done2(skb, 0);
225 }
226
esp6_xmit(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)227 static int esp6_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
228 {
229 int err;
230 int alen;
231 int blksize;
232 struct xfrm_offload *xo;
233 struct ip_esp_hdr *esph;
234 struct crypto_aead *aead;
235 struct esp_info esp;
236 bool hw_offload = true;
237
238 esp.inplace = true;
239
240 xo = xfrm_offload(skb);
241
242 if (!xo)
243 return -EINVAL;
244
245 if (!(features & NETIF_F_HW_ESP) || !x->xso.offload_handle ||
246 (x->xso.dev != skb->dev)) {
247 xo->flags |= CRYPTO_FALLBACK;
248 hw_offload = false;
249 }
250
251 esp.proto = xo->proto;
252
253 /* skb is pure payload to encrypt */
254
255 aead = x->data;
256 alen = crypto_aead_authsize(aead);
257
258 esp.tfclen = 0;
259 /* XXX: Add support for tfc padding here. */
260
261 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
262 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
263 esp.plen = esp.clen - skb->len - esp.tfclen;
264 esp.tailen = esp.tfclen + esp.plen + alen;
265
266 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
267 esp.nfrags = esp6_output_head(x, skb, &esp);
268 if (esp.nfrags < 0)
269 return esp.nfrags;
270 }
271
272 esph = ip_esp_hdr(skb);
273 esph->spi = x->id.spi;
274
275 skb_push(skb, -skb_network_offset(skb));
276
277 if (xo->flags & XFRM_GSO_SEGMENT) {
278 esph->seq_no = htonl(xo->seq.low);
279 } else {
280 int len;
281
282 len = skb->len - sizeof(struct ipv6hdr);
283 if (len > IPV6_MAXPLEN)
284 len = 0;
285
286 ipv6_hdr(skb)->payload_len = htons(len);
287 }
288
289 if (hw_offload)
290 return 0;
291
292 esp.seqno = cpu_to_be64(xo->seq.low + ((u64)xo->seq.hi << 32));
293
294 err = esp6_output_tail(x, skb, &esp);
295 if (err)
296 return err;
297
298 secpath_reset(skb);
299
300 return 0;
301 }
302
303 static const struct net_offload esp6_offload = {
304 .callbacks = {
305 .gro_receive = esp6_gro_receive,
306 .gso_segment = esp6_gso_segment,
307 },
308 };
309
310 static const struct xfrm_type_offload esp6_type_offload = {
311 .description = "ESP6 OFFLOAD",
312 .owner = THIS_MODULE,
313 .proto = IPPROTO_ESP,
314 .input_tail = esp6_input_tail,
315 .xmit = esp6_xmit,
316 .encap = esp6_gso_encap,
317 };
318
esp6_offload_init(void)319 static int __init esp6_offload_init(void)
320 {
321 if (xfrm_register_type_offload(&esp6_type_offload, AF_INET6) < 0) {
322 pr_info("%s: can't add xfrm type offload\n", __func__);
323 return -EAGAIN;
324 }
325
326 return inet6_add_offload(&esp6_offload, IPPROTO_ESP);
327 }
328
esp6_offload_exit(void)329 static void __exit esp6_offload_exit(void)
330 {
331 if (xfrm_unregister_type_offload(&esp6_type_offload, AF_INET6) < 0)
332 pr_info("%s: can't remove xfrm type offload\n", __func__);
333
334 inet6_del_offload(&esp6_offload, IPPROTO_ESP);
335 }
336
337 module_init(esp6_offload_init);
338 module_exit(esp6_offload_exit);
339 MODULE_LICENSE("GPL");
340 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
341 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET6, XFRM_PROTO_ESP);
342