1/*
2 * IPV4 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/udp.h>
30
31static struct sk_buff *esp4_gro_receive(struct list_head *head,
32 struct sk_buff *skb)
33{
34 int offset = skb_gro_offset(skb);
35 struct xfrm_offload *xo;
36 struct xfrm_state *x;
37 __be32 seq;
38 __be32 spi;
39 int err;
40
41 if (!pskb_pull(skb, offset))
42 return NULL;
43
44 if ((err = xfrm_parse_spi(skb, IPPROTO_ESP, &spi, &seq)) != 0)
45 goto out;
46
47 xo = xfrm_offload(skb);
48 if (!xo || !(xo->flags & CRYPTO_DONE)) {
49 err = secpath_set(skb);
50 if (err)
51 goto out;
52
53 if (skb->sp->len == XFRM_MAX_DEPTH)
54 goto out;
55
56 x = xfrm_state_lookup(dev_net(skb->dev), skb->mark,
57 (xfrm_address_t *)&ip_hdr(skb)->daddr,
58 spi, IPPROTO_ESP, AF_INET);
59 if (!x)
60 goto out;
61
62 skb->sp->xvec[skb->sp->len++] = x;
63 skb->sp->olen++;
64
65 xo = xfrm_offload(skb);
66 if (!xo) {
67 xfrm_state_put(x);
68 goto out;
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);
84out:
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
92static 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
109static struct sk_buff *esp4_gso_segment(struct sk_buff *skb,
110 netdev_features_t features)
111{
112 struct xfrm_state *x;
113 struct ip_esp_hdr *esph;
114 struct crypto_aead *aead;
115 netdev_features_t esp_features = features;
116 struct xfrm_offload *xo = xfrm_offload(skb);
117
118 if (!xo)
119 return ERR_PTR(-EINVAL);
120
121 if (!(skb_shinfo(skb)->gso_type & SKB_GSO_ESP))
122 return ERR_PTR(-EINVAL);
123
124 x = skb->sp->xvec[skb->sp->len - 1];
125 aead = x->data;
126 esph = ip_esp_hdr(skb);
127
128 if (esph->spi != x->id.spi)
129 return ERR_PTR(-EINVAL);
130
131 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
132 return ERR_PTR(-EINVAL);
133
134 __skb_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead));
135
136 skb->encap_hdr_csum = 1;
137
138 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev)
139 esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
140 else if (!(features & NETIF_F_HW_ESP_TX_CSUM))
141 esp_features = features & ~NETIF_F_CSUM_MASK;
142
143 xo->flags |= XFRM_GSO_SEGMENT;
144
145 return x->outer_mode->gso_segment(x, skb, esp_features);
146}
147
148static int esp_input_tail(struct xfrm_state *x, struct sk_buff *skb)
149{
150 struct crypto_aead *aead = x->data;
151 struct xfrm_offload *xo = xfrm_offload(skb);
152
153 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead)))
154 return -EINVAL;
155
156 if (!(xo->flags & CRYPTO_DONE))
157 skb->ip_summed = CHECKSUM_NONE;
158
159 return esp_input_done2(skb, 0);
160}
161
162static int esp_xmit(struct xfrm_state *x, struct sk_buff *skb, netdev_features_t features)
163{
164 int err;
165 int alen;
166 int blksize;
167 struct xfrm_offload *xo;
168 struct ip_esp_hdr *esph;
169 struct crypto_aead *aead;
170 struct esp_info esp;
171 bool hw_offload = true;
172 __u32 seq;
173
174 esp.inplace = true;
175
176 xo = xfrm_offload(skb);
177
178 if (!xo)
179 return -EINVAL;
180
181 if (!(features & NETIF_F_HW_ESP) || x->xso.dev != skb->dev) {
182 xo->flags |= CRYPTO_FALLBACK;
183 hw_offload = false;
184 }
185
186 esp.proto = xo->proto;
187
188 /* skb is pure payload to encrypt */
189
190 aead = x->data;
191 alen = crypto_aead_authsize(aead);
192
193 esp.tfclen = 0;
194 /* XXX: Add support for tfc padding here. */
195
196 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
197 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
198 esp.plen = esp.clen - skb->len - esp.tfclen;
199 esp.tailen = esp.tfclen + esp.plen + alen;
200
201 esp.esph = ip_esp_hdr(skb);
202
203
204 if (!hw_offload || (hw_offload && !skb_is_gso(skb))) {
205 esp.nfrags = esp_output_head(x, skb, &esp);
206 if (esp.nfrags < 0)
207 return esp.nfrags;
208 }
209
210 seq = xo->seq.low;
211
212 esph = esp.esph;
213 esph->spi = x->id.spi;
214
215 skb_push(skb, -skb_network_offset(skb));
216
217 if (xo->flags & XFRM_GSO_SEGMENT) {
218 esph->seq_no = htonl(seq);
219
220 if (!skb_is_gso(skb))
221 xo->seq.low++;
222 else
223 xo->seq.low += skb_shinfo(skb)->gso_segs;
224 }
225
226 esp.seqno = cpu_to_be64(seq + ((u64)xo->seq.hi << 32));
227
228 ip_hdr(skb)->tot_len = htons(skb->len);
229 ip_send_check(ip_hdr(skb));
230
231 if (hw_offload)
232 return 0;
233
234 err = esp_output_tail(x, skb, &esp);
235 if (err)
236 return err;
237
238 secpath_reset(skb);
239
240 return 0;
241}
242
243static const struct net_offload esp4_offload = {
244 .callbacks = {
245 .gro_receive = esp4_gro_receive,
246 .gso_segment = esp4_gso_segment,
247 },
248};
249
250static const struct xfrm_type_offload esp_type_offload = {
251 .description = "ESP4 OFFLOAD",
252 .owner = THIS_MODULE,
253 .proto = IPPROTO_ESP,
254 .input_tail = esp_input_tail,
255 .xmit = esp_xmit,
256 .encap = esp4_gso_encap,
257};
258
259static int __init esp4_offload_init(void)
260{
261 if (xfrm_register_type_offload(&esp_type_offload, AF_INET) < 0) {
262 pr_info("%s: can't add xfrm type offload\n", __func__);
263 return -EAGAIN;
264 }
265
266 return inet_add_offload(&esp4_offload, IPPROTO_ESP);
267}
268
269static void __exit esp4_offload_exit(void)
270{
271 if (xfrm_unregister_type_offload(&esp_type_offload, AF_INET) < 0)
272 pr_info("%s: can't remove xfrm type offload\n", __func__);
273
274 inet_del_offload(&esp4_offload, IPPROTO_ESP);
275}
276
277module_init(esp4_offload_init);
278module_exit(esp4_offload_exit);
279MODULE_LICENSE("GPL");
280MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
281MODULE_ALIAS_XFRM_OFFLOAD_TYPE(AF_INET, XFRM_PROTO_ESP);
282