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/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/udp.h>
29
esp4_gro_receive(struct list_head * head,struct sk_buff * skb)30 static struct sk_buff *esp4_gro_receive(struct list_head *head,
31 struct sk_buff *skb)
32 {
33 int offset = skb_gro_offset(skb);
34 struct xfrm_offload *xo;
35 struct xfrm_state *x;
36 __be32 seq;
37 __be32 spi;
38
39 if (!pskb_pull(skb, offset))
40 return NULL;
41
42 if (xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq) != 0)
43 goto out;
44
45 xo = xfrm_offload(skb);
46 if (!xo || !(xo->flags & CRYPTO_DONE)) {
47 struct sec_path *sp = secpath_set(skb);
48
49 if (!sp)
50 goto out;
51
52 if (sp->len == XFRM_MAX_DEPTH)
53 goto out_reset;
54
55 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
56 (xfrm_address_t *)&ip_hdr(skb)->daddr,
57 spi, IPPROTO_ESP, AF_INET);
58 if (!x)
59 goto out_reset;
60
61 skb->mark = xfrm_smark_get(skb->mark, x);
62
63 sp->xvec[sp->len++] = x;
64 sp->olen++;
65
66 xo = xfrm_offload(skb);
67 if (!xo)
68 goto out_reset;
69 }
70
71 xo->flags |= XFRM_GRO;
72
73 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
74 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
75 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
76 XFRM_SPI_SKB_CB(skb)->seq = seq;
77
78 /* We don't need to handle errors from xfrm_input, it does all
79 * the error handling and frees the resources on error. */
80 xfrm_input(skb, IPPROTO_ESP, spi, -2);
81
82 return ERR_PTR(-EINPROGRESS);
83 out_reset:
84 secpath_reset(skb);
85 out:
86 skb_push(skb, offset);
87 NAPI_GRO_CB(skb)->same_flow = 0;
88 NAPI_GRO_CB(skb)->flush = 1;
89
90 return NULL;
91 }
92
esp4_gso_encap(struct xfrm_state * x,struct sk_buff * skb)93 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
94 {
95 struct ip_esp_hdr *esph;
96 struct iphdr *iph = ip_hdr(skb);
97 struct xfrm_offload *xo = xfrm_offload(skb);
98 int proto = iph->protocol;
99
100 skb_push(skb, -skb_network_offset(skb));
101 esph = ip_esp_hdr(skb);
102 *skb_mac_header(skb) = IPPROTO_ESP;
103
104 esph->spi = x->id.spi;
105 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
106
107 xo->proto = proto;
108 }
109
xfrm4_tunnel_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)110 static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
111 struct sk_buff *skb,
112 netdev_features_t features)
113 {
114 __be16 type = x->inner_mode.family == AF_INET6 ? htons(ETH_P_IPV6)
115 : htons(ETH_P_IP);
116
117 return skb_eth_gso_segment(skb, features, type);
118 }
119
xfrm4_transport_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)120 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
121 struct sk_buff *skb,
122 netdev_features_t features)
123 {
124 const struct net_offload *ops;
125 struct sk_buff *segs = ERR_PTR(-EINVAL);
126 struct xfrm_offload *xo = xfrm_offload(skb);
127
128 skb->transport_header += x->props.header_len;
129 ops = rcu_dereference(inet_offloads[xo->proto]);
130 if (likely(ops && ops->callbacks.gso_segment))
131 segs = ops->callbacks.gso_segment(skb, features);
132
133 return segs;
134 }
135
xfrm4_beet_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)136 static struct sk_buff *xfrm4_beet_gso_segment(struct xfrm_state *x,
137 struct sk_buff *skb,
138 netdev_features_t features)
139 {
140 struct xfrm_offload *xo = xfrm_offload(skb);
141 struct sk_buff *segs = ERR_PTR(-EINVAL);
142 const struct net_offload *ops;
143 u8 proto = xo->proto;
144
145 skb->transport_header += x->props.header_len;
146
147 if (x->sel.family != AF_INET6) {
148 if (proto == IPPROTO_BEETPH) {
149 struct ip_beet_phdr *ph =
150 (struct ip_beet_phdr *)skb->data;
151
152 skb->transport_header += ph->hdrlen * 8;
153 proto = ph->nexthdr;
154 } else {
155 skb->transport_header -= IPV4_BEET_PHMAXLEN;
156 }
157 } else {
158 __be16 frag;
159
160 skb->transport_header +=
161 ipv6_skip_exthdr(skb, 0, &proto, &frag);
162 if (proto == IPPROTO_TCP)
163 skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
164 }
165
166 if (proto == IPPROTO_IPV6)
167 skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
168
169 __skb_pull(skb, skb_transport_offset(skb));
170 ops = rcu_dereference(inet_offloads[proto]);
171 if (likely(ops && ops->callbacks.gso_segment))
172 segs = ops->callbacks.gso_segment(skb, features);
173
174 return segs;
175 }
176
xfrm4_outer_mode_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)177 static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
178 struct sk_buff *skb,
179 netdev_features_t features)
180 {
181 switch (x->outer_mode.encap) {
182 case XFRM_MODE_TUNNEL:
183 return xfrm4_tunnel_gso_segment(x, skb, features);
184 case XFRM_MODE_TRANSPORT:
185 return xfrm4_transport_gso_segment(x, skb, features);
186 case XFRM_MODE_BEET:
187 return xfrm4_beet_gso_segment(x, skb, features);
188 }
189
190 return ERR_PTR(-EOPNOTSUPP);
191 }
192
esp4_gso_segment(struct sk_buff * skb,netdev_features_t features)193 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
194 netdev_features_t features)
195 {
196 struct xfrm_state *x;
197 struct ip_esp_hdr *esph;
198 struct crypto_aead *aead;
199 netdev_features_t esp_features = features;
200 struct xfrm_offload *xo = xfrm_offload(skb);
201 struct sec_path *sp;
202
203 if (!xo)
204 return ERR_PTR(-EINVAL);
205
206 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
207 return ERR_PTR(-EINVAL);
208
209 sp = skb_sec_path(skb);
210 x = sp->xvec[sp->len - 1];
211 aead = x->data;
212 esph = ip_esp_hdr(skb);
213
214 if (esph->spi != x->id.spi)
215 return ERR_PTR(-EINVAL);
216
217 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
218 return ERR_PTR(-EINVAL);
219
220 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
221
222 skb->encap_hdr_csum = 1;
223
224 if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
225 !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
226 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK |
227 NETIF_F_SCTP_CRC);
228 else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
229 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
230 esp_features = features & ~(NETIF_F_CSUM_MASK |
231 NETIF_F_SCTP_CRC);
232
233 xo->flags |= XFRM_GSO_SEGMENT;
234
235 return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
236 }
237
esp_input_tail(struct xfrm_state * x,struct sk_buff * skb)238 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
239 {
240 struct crypto_aead *aead = x->data;
241 struct xfrm_offload *xo = xfrm_offload(skb);
242
243 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
244 return -EINVAL;
245
246 if (!(xo->flags & CRYPTO_DONE))
247 skb->ip_summed = CHECKSUM_NONE;
248
249 return esp_input_done2(skb, 0);
250 }
251
esp_xmit(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)252 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
253 {
254 int err;
255 int alen;
256 int blksize;
257 struct xfrm_offload *xo;
258 struct ip_esp_hdr *esph;
259 struct crypto_aead *aead;
260 struct esp_info esp;
261 bool hw_offload = true;
262 __u32 seq;
263
264 esp.inplace = true;
265
266 xo = xfrm_offload(skb);
267
268 if (!xo)
269 return -EINVAL;
270
271 if ((!(features & NETIF_F_HW_ESP) &&
272 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
273 x->xso.dev != skb->dev) {
274 xo->flags |= CRYPTO_FALLBACK;
275 hw_offload = false;
276 }
277
278 esp.proto = xo->proto;
279
280 /* skb is pure payload to encrypt */
281
282 aead = x->data;
283 alen = crypto_aead_authsize(aead);
284
285 esp.tfclen = 0;
286 /* XXX: Add support for tfc padding here. */
287
288 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
289 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
290 esp.plen = esp.clen - skb->len - esp.tfclen;
291 esp.tailen = esp.tfclen + esp.plen + alen;
292
293 esp.esph = ip_esp_hdr(skb);
294
295
296 if (!hw_offload || !skb_is_gso(skb)) {
297 esp.nfrags = esp_output_head(x, skb, &esp);
298 if (esp.nfrags < 0)
299 return esp.nfrags;
300 }
301
302 seq = xo->seq.low;
303
304 esph = esp.esph;
305 esph->spi = x->id.spi;
306
307 skb_push(skb, -skb_network_offset(skb));
308
309 if (xo->flags & XFRM_GSO_SEGMENT) {
310 esph->seq_no = htonl(seq);
311
312 if (!skb_is_gso(skb))
313 xo->seq.low++;
314 else
315 xo->seq.low += skb_shinfo(skb)->gso_segs;
316 }
317
318 if (xo->seq.low < seq)
319 xo->seq.hi++;
320
321 esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
322
323 ip_hdr(skb)->tot_len = htons(skb->len);
324 ip_send_check(ip_hdr(skb));
325
326 if (hw_offload) {
327 if (!skb_ext_add(skb, SKB_EXT_SEC_PATH))
328 return -ENOMEM;
329
330 xo = xfrm_offload(skb);
331 if (!xo)
332 return -EINVAL;
333
334 xo->flags |= XFRM_XMIT;
335 return 0;
336 }
337
338 err = esp_output_tail(x, skb, &esp);
339 if (err)
340 return err;
341
342 secpath_reset(skb);
343
344 if (skb_needs_linearize(skb, skb->dev->features) &&
345 __skb_linearize(skb))
346 return -ENOMEM;
347 return 0;
348 }
349
350 static const struct net_offload esp4_offload = {
351 .callbacks = {
352 .gro_receive = esp4_gro_receive,
353 .gso_segment = esp4_gso_segment,
354 },
355 };
356
357 static const struct xfrm_type_offload esp_type_offload = {
358 .owner = THIS_MODULE,
359 .proto = IPPROTO_ESP,
360 .input_tail = esp_input_tail,
361 .xmit = esp_xmit,
362 .encap = esp4_gso_encap,
363 };
364
esp4_offload_init(void)365 static int __init esp4_offload_init(void)
366 {
367 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
368 pr_info("%s: can't add xfrm type offload\n", __func__);
369 return -EAGAIN;
370 }
371
372 return inet_add_offload(&esp4_offload, IPPROTO_ESP);
373 }
374
esp4_offload_exit(void)375 static void __exit esp4_offload_exit(void)
376 {
377 xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
378 inet_del_offload(&esp4_offload, IPPROTO_ESP);
379 }
380
381 module_init(esp4_offload_init);
382 module_exit(esp4_offload_exit);
383 MODULE_LICENSE("GPL");
384 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
385 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
386 MODULE_DESCRIPTION("IPV4 GSO/GRO offload support");
387