1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * IPV4 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/udp.h>
27
esp4_gro_receive(struct list_head * head,struct sk_buff * skb)28 static struct sk_buff *esp4_gro_receive(struct list_head *head,
29 struct sk_buff *skb)
30 {
31 int offset = skb_gro_offset(skb);
32 struct xfrm_offload *xo;
33 struct xfrm_state *x;
34 __be32 seq;
35 __be32 spi;
36 int err;
37
38 if (!pskb_pull(skb, offset))
39 return NULL;
40
41 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
42 goto out;
43
44 xo = xfrm_offload(skb);
45 if (!xo || !(xo->flags & CRYPTO_DONE)) {
46 struct sec_path *sp = secpath_set(skb);
47
48 if (!sp)
49 goto out;
50
51 if (sp->len == XFRM_MAX_DEPTH)
52 goto out_reset;
53
54 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
55 (xfrm_address_t *)&ip_hdr(skb)->daddr,
56 spi, IPPROTO_ESP, AF_INET);
57 if (!x)
58 goto out_reset;
59
60 skb->mark = xfrm_smark_get(skb->mark, x);
61
62 sp->xvec[sp->len++] = x;
63 sp->olen++;
64
65 xo = xfrm_offload(skb);
66 if (!xo)
67 goto out_reset;
68 }
69
70 xo->flags |= XFRM_GRO;
71
72 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
73 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
74 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
75 XFRM_SPI_SKB_CB(skb)->seq = seq;
76
77 /* We don't need to handle errors from xfrm_input, it does all
78 * the error handling and frees the resources on error. */
79 xfrm_input(skb, IPPROTO_ESP, spi, -2);
80
81 return ERR_PTR(-EINPROGRESS);
82 out_reset:
83 secpath_reset(skb);
84 out:
85 skb_push(skb, offset);
86 NAPI_GRO_CB(skb)->same_flow = 0;
87 NAPI_GRO_CB(skb)->flush = 1;
88
89 return NULL;
90 }
91
esp4_gso_encap(struct xfrm_state * x,struct sk_buff * skb)92 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
93 {
94 struct ip_esp_hdr *esph;
95 struct iphdr *iph = ip_hdr(skb);
96 struct xfrm_offload *xo = xfrm_offload(skb);
97 int proto = iph->protocol;
98
99 skb_push(skb, -skb_network_offset(skb));
100 esph = ip_esp_hdr(skb);
101 *skb_mac_header(skb) = IPPROTO_ESP;
102
103 esph->spi = x->id.spi;
104 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
105
106 xo->proto = proto;
107 }
108
xfrm4_tunnel_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)109 static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
110 struct sk_buff *skb,
111 netdev_features_t features)
112 {
113 __skb_push(skb, skb->mac_len);
114 return skb_mac_gso_segment(skb, features);
115 }
116
xfrm4_transport_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)117 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
118 struct sk_buff *skb,
119 netdev_features_t features)
120 {
121 const struct net_offload *ops;
122 struct sk_buff *segs = ERR_PTR(-EINVAL);
123 struct xfrm_offload *xo = xfrm_offload(skb);
124
125 skb->transport_header += x->props.header_len;
126 ops = rcu_dereference(inet_offloads[xo->proto]);
127 if (likely(ops && ops->callbacks.gso_segment))
128 segs = ops->callbacks.gso_segment(skb, features);
129
130 return segs;
131 }
132
xfrm4_beet_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)133 static struct sk_buff *xfrm4_beet_gso_segment(struct xfrm_state *x,
134 struct sk_buff *skb,
135 netdev_features_t features)
136 {
137 struct xfrm_offload *xo = xfrm_offload(skb);
138 struct sk_buff *segs = ERR_PTR(-EINVAL);
139 const struct net_offload *ops;
140 u8 proto = xo->proto;
141
142 skb->transport_header += x->props.header_len;
143
144 if (x->sel.family != AF_INET6) {
145 if (proto == IPPROTO_BEETPH) {
146 struct ip_beet_phdr *ph =
147 (struct ip_beet_phdr *)skb->data;
148
149 skb->transport_header += ph->hdrlen * 8;
150 proto = ph->nexthdr;
151 } else {
152 skb->transport_header -= IPV4_BEET_PHMAXLEN;
153 }
154 } else {
155 __be16 frag;
156
157 skb->transport_header +=
158 ipv6_skip_exthdr(skb, 0, &proto, &frag);
159 if (proto == IPPROTO_TCP)
160 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
161 }
162
163 if (proto == IPPROTO_IPV6)
164 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
165
166 __skb_pull(skb, skb_transport_offset(skb));
167 ops = rcu_dereference(inet_offloads[proto]);
168 if (likely(ops && ops->callbacks.gso_segment))
169 segs = ops->callbacks.gso_segment(skb, features);
170
171 return segs;
172 }
173
xfrm4_outer_mode_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)174 static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
175 struct sk_buff *skb,
176 netdev_features_t features)
177 {
178 switch (x->outer_mode.encap) {
179 case XFRM_MODE_TUNNEL:
180 return xfrm4_tunnel_gso_segment(x, skb, features);
181 case XFRM_MODE_TRANSPORT:
182 return xfrm4_transport_gso_segment(x, skb, features);
183 case XFRM_MODE_BEET:
184 return xfrm4_beet_gso_segment(x, skb, features);
185 }
186
187 return ERR_PTR(-EOPNOTSUPP);
188 }
189
esp4_gso_segment(struct sk_buff * skb,netdev_features_t features)190 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
191 netdev_features_t features)
192 {
193 struct xfrm_state *x;
194 struct ip_esp_hdr *esph;
195 struct crypto_aead *aead;
196 netdev_features_t esp_features = features;
197 struct xfrm_offload *xo = xfrm_offload(skb);
198 struct sec_path *sp;
199
200 if (!xo)
201 return ERR_PTR(-EINVAL);
202
203 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
204 return ERR_PTR(-EINVAL);
205
206 sp = skb_sec_path(skb);
207 x = sp->xvec[sp->len - 1];
208 aead = x->data;
209 esph = ip_esp_hdr(skb);
210
211 if (esph->spi != x->id.spi)
212 return ERR_PTR(-EINVAL);
213
214 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
215 return ERR_PTR(-EINVAL);
216
217 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
218
219 skb->encap_hdr_csum = 1;
220
221 if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
222 !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
223 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
224 NETIF_F_SCTP_CRC);
225 else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
226 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
227 esp_features = features & ~(NETIF_F_CSUM_MASK |
228 NETIF_F_SCTP_CRC);
229
230 xo->flags |= XFRM_GSO_SEGMENT;
231
232 return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
233 }
234
esp_input_tail(struct xfrm_state * x,struct sk_buff * skb)235 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
236 {
237 struct crypto_aead *aead = x->data;
238 struct xfrm_offload *xo = xfrm_offload(skb);
239
240 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
241 return -EINVAL;
242
243 if (!(xo->flags & CRYPTO_DONE))
244 skb->ip_summed = CHECKSUM_NONE;
245
246 return esp_input_done2(skb, 0);
247 }
248
esp_xmit(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)249 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
250 {
251 int err;
252 int alen;
253 int blksize;
254 struct xfrm_offload *xo;
255 struct ip_esp_hdr *esph;
256 struct crypto_aead *aead;
257 struct esp_info esp;
258 bool hw_offload = true;
259 __u32 seq;
260
261 esp.inplace = true;
262
263 xo = xfrm_offload(skb);
264
265 if (!xo)
266 return -EINVAL;
267
268 if ((!(features & NETIF_F_HW_ESP) &&
269 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
270 x->xso.dev != skb->dev) {
271 xo->flags |= CRYPTO_FALLBACK;
272 hw_offload = false;
273 }
274
275 esp.proto = xo->proto;
276
277 /* skb is pure payload to encrypt */
278
279 aead = x->data;
280 alen = crypto_aead_authsize(aead);
281
282 esp.tfclen = 0;
283 /* XXX: Add support for tfc padding here. */
284
285 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
286 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
287 esp.plen = esp.clen - skb->len - esp.tfclen;
288 esp.tailen = esp.tfclen + esp.plen + alen;
289
290 esp.esph = ip_esp_hdr(skb);
291
292
293 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
294 esp.nfrags = esp_output_head(x, skb, &esp);
295 if (esp.nfrags < 0)
296 return esp.nfrags;
297 }
298
299 seq = xo->seq.low;
300
301 esph = esp.esph;
302 esph->spi = x->id.spi;
303
304 skb_push(skb, -skb_network_offset(skb));
305
306 if (xo->flags & XFRM_GSO_SEGMENT) {
307 esph->seq_no = htonl(seq);
308
309 if (!skb_is_gso(skb))
310 xo->seq.low++;
311 else
312 xo->seq.low += skb_shinfo(skb)->gso_segs;
313 }
314
315 if (xo->seq.low < seq)
316 xo->seq.hi++;
317
318 esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
319
320 ip_hdr(skb)->tot_len = htons(skb->len);
321 ip_send_check(ip_hdr(skb));
322
323 if (hw_offload) {
324 if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
325 return -ENOMEM;
326
327 xo = xfrm_offload(skb);
328 if (!xo)
329 return -EINVAL;
330
331 xo->flags |= XFRM_XMIT;
332 return 0;
333 }
334
335 err = esp_output_tail(x, skb, &esp);
336 if (err)
337 return err;
338
339 secpath_reset(skb);
340
341 if (skb_needs_linearize(skb, skb->dev->features) &&
342 __skb_linearize(skb))
343 return -ENOMEM;
344 return 0;
345 }
346
347 static const struct net_offload esp4_offload = {
348 .callbacks = {
349 .gro_receive = esp4_gro_receive,
350 .gso_segment = esp4_gso_segment,
351 },
352 };
353
354 static const struct xfrm_type_offload esp_type_offload = {
355 .description = "ESP4 OFFLOAD",
356 .owner = THIS_MODULE,
357 .proto = IPPROTO_ESP,
358 .input_tail = esp_input_tail,
359 .xmit = esp_xmit,
360 .encap = esp4_gso_encap,
361 };
362
esp4_offload_init(void)363 static int __init esp4_offload_init(void)
364 {
365 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
366 pr_info("%s: can't add xfrm type offload\n", __func__);
367 return -EAGAIN;
368 }
369
370 return inet_add_offload(&esp4_offload, IPPROTO_ESP);
371 }
372
esp4_offload_exit(void)373 static void __exit esp4_offload_exit(void)
374 {
375 xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
376 inet_del_offload(&esp4_offload, IPPROTO_ESP);
377 }
378
379 module_init(esp4_offload_init);
380 module_exit(esp4_offload_exit);
381 MODULE_LICENSE("GPL");
382 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
383 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
384 MODULE_DESCRIPTION("IPV4 GSO/GRO offload support");
385