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 xfrm_state_put(x);
68 goto out_reset;
69 }
70 }
71
72 xo->flags |= XFRM_GRO;
73
74 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
75 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
76 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
77 XFRM_SPI_SKB_CB(skb)->seq = seq;
78
79 /* We don't need to handle errors from xfrm_input, it does all
80 * the error handling and frees the resources on error. */
81 xfrm_input(skb, IPPROTO_ESP, spi, -2);
82
83 return ERR_PTR(-EINPROGRESS);
84 out_reset:
85 secpath_reset(skb);
86 out:
87 skb_push(skb, offset);
88 NAPI_GRO_CB(skb)->same_flow = 0;
89 NAPI_GRO_CB(skb)->flush = 1;
90
91 return NULL;
92 }
93
esp4_gso_encap(struct xfrm_state * x,struct sk_buff * skb)94 static void esp4_gso_encap(struct xfrm_state *x, struct sk_buff *skb)
95 {
96 struct ip_esp_hdr *esph;
97 struct iphdr *iph = ip_hdr(skb);
98 struct xfrm_offload *xo = xfrm_offload(skb);
99 int proto = iph->protocol;
100
101 skb_push(skb, -skb_network_offset(skb));
102 esph = ip_esp_hdr(skb);
103 *skb_mac_header(skb) = IPPROTO_ESP;
104
105 esph->spi = x->id.spi;
106 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
107
108 xo->proto = proto;
109 }
110
xfrm4_tunnel_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)111 static struct sk_buff *xfrm4_tunnel_gso_segment(struct xfrm_state *x,
112 struct sk_buff *skb,
113 netdev_features_t features)
114 {
115 __skb_push(skb, skb->mac_len);
116 return skb_mac_gso_segment(skb, features);
117 }
118
xfrm4_transport_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)119 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
120 struct sk_buff *skb,
121 netdev_features_t features)
122 {
123 const struct net_offload *ops;
124 struct sk_buff *segs = ERR_PTR(-EINVAL);
125 struct xfrm_offload *xo = xfrm_offload(skb);
126
127 skb->transport_header += x->props.header_len;
128 ops = rcu_dereference(inet_offloads[xo->proto]);
129 if (likely(ops && ops->callbacks.gso_segment))
130 segs = ops->callbacks.gso_segment(skb, features);
131
132 return segs;
133 }
134
xfrm4_outer_mode_gso_segment(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)135 static struct sk_buff *xfrm4_outer_mode_gso_segment(struct xfrm_state *x,
136 struct sk_buff *skb,
137 netdev_features_t features)
138 {
139 switch (x->outer_mode.encap) {
140 case XFRM_MODE_TUNNEL:
141 return xfrm4_tunnel_gso_segment(x, skb, features);
142 case XFRM_MODE_TRANSPORT:
143 return xfrm4_transport_gso_segment(x, skb, features);
144 }
145
146 return ERR_PTR(-EOPNOTSUPP);
147 }
148
esp4_gso_segment(struct sk_buff * skb,netdev_features_t features)149 static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
150 netdev_features_t features)
151 {
152 struct xfrm_state *x;
153 struct ip_esp_hdr *esph;
154 struct crypto_aead *aead;
155 netdev_features_t esp_features = features;
156 struct xfrm_offload *xo = xfrm_offload(skb);
157 struct sec_path *sp;
158
159 if (!xo)
160 return ERR_PTR(-EINVAL);
161
162 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
163 return ERR_PTR(-EINVAL);
164
165 sp = skb_sec_path(skb);
166 x = sp->xvec[sp->len - 1];
167 aead = x->data;
168 esph = ip_esp_hdr(skb);
169
170 if (esph->spi != x->id.spi)
171 return ERR_PTR(-EINVAL);
172
173 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
174 return ERR_PTR(-EINVAL);
175
176 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
177
178 skb->encap_hdr_csum = 1;
179
180 if ((!(skb->dev->gso_partial_features & NETIF_F_HW_ESP) &&
181 !(features & NETIF_F_HW_ESP)) || x->xso.dev != skb->dev)
182 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
183 else if (!(features & NETIF_F_HW_ESP_TX_CSUM) &&
184 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP_TX_CSUM))
185 esp_features = features & ~NETIF_F_CSUM_MASK;
186
187 xo->flags |= XFRM_GSO_SEGMENT;
188
189 return xfrm4_outer_mode_gso_segment(x, skb, esp_features);
190 }
191
esp_input_tail(struct xfrm_state * x,struct sk_buff * skb)192 static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
193 {
194 struct crypto_aead *aead = x->data;
195 struct xfrm_offload *xo = xfrm_offload(skb);
196
197 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
198 return -EINVAL;
199
200 if (!(xo->flags & CRYPTO_DONE))
201 skb->ip_summed = CHECKSUM_NONE;
202
203 return esp_input_done2(skb, 0);
204 }
205
esp_xmit(struct xfrm_state * x,struct sk_buff * skb,netdev_features_t features)206 static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
207 {
208 int err;
209 int alen;
210 int blksize;
211 struct xfrm_offload *xo;
212 struct ip_esp_hdr *esph;
213 struct crypto_aead *aead;
214 struct esp_info esp;
215 bool hw_offload = true;
216 __u32 seq;
217
218 esp.inplace = true;
219
220 xo = xfrm_offload(skb);
221
222 if (!xo)
223 return -EINVAL;
224
225 if ((!(features & NETIF_F_HW_ESP) &&
226 !(skb->dev->gso_partial_features & NETIF_F_HW_ESP)) ||
227 x->xso.dev != skb->dev) {
228 xo->flags |= CRYPTO_FALLBACK;
229 hw_offload = false;
230 }
231
232 esp.proto = xo->proto;
233
234 /* skb is pure payload to encrypt */
235
236 aead = x->data;
237 alen = crypto_aead_authsize(aead);
238
239 esp.tfclen = 0;
240 /* XXX: Add support for tfc padding here. */
241
242 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
243 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
244 esp.plen = esp.clen - skb->len - esp.tfclen;
245 esp.tailen = esp.tfclen + esp.plen + alen;
246
247 esp.esph = ip_esp_hdr(skb);
248
249
250 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
251 esp.nfrags = esp_output_head(x, skb, &esp);
252 if (esp.nfrags < 0)
253 return esp.nfrags;
254 }
255
256 seq = xo->seq.low;
257
258 esph = esp.esph;
259 esph->spi = x->id.spi;
260
261 skb_push(skb, -skb_network_offset(skb));
262
263 if (xo->flags & XFRM_GSO_SEGMENT) {
264 esph->seq_no = htonl(seq);
265
266 if (!skb_is_gso(skb))
267 xo->seq.low++;
268 else
269 xo->seq.low += skb_shinfo(skb)->gso_segs;
270 }
271
272 esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
273
274 ip_hdr(skb)->tot_len = htons(skb->len);
275 ip_send_check(ip_hdr(skb));
276
277 if (hw_offload)
278 return 0;
279
280 err = esp_output_tail(x, skb, &esp);
281 if (err)
282 return err;
283
284 secpath_reset(skb);
285
286 return 0;
287 }
288
289 static const struct net_offload esp4_offload = {
290 .callbacks = {
291 .gro_receive = esp4_gro_receive,
292 .gso_segment = esp4_gso_segment,
293 },
294 };
295
296 static const struct xfrm_type_offload esp_type_offload = {
297 .description = "ESP4 OFFLOAD",
298 .owner = THIS_MODULE,
299 .proto = IPPROTO_ESP,
300 .input_tail = esp_input_tail,
301 .xmit = esp_xmit,
302 .encap = esp4_gso_encap,
303 };
304
esp4_offload_init(void)305 static int __init esp4_offload_init(void)
306 {
307 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
308 pr_info("%s: can't add xfrm type offload\n", __func__);
309 return -EAGAIN;
310 }
311
312 return inet_add_offload(&esp4_offload, IPPROTO_ESP);
313 }
314
esp4_offload_exit(void)315 static void __exit esp4_offload_exit(void)
316 {
317 xfrm_unregister_type_offload(&esp_type_offload, AF_INET);
318 inet_del_offload(&esp4_offload, IPPROTO_ESP);
319 }
320
321 module_init(esp4_offload_init);
322 module_exit(esp4_offload_exit);
323 MODULE_LICENSE("GPL");
324 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
325 MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
326