summaryrefslogtreecommitdiffstats
path: root/drivers/net/netdevsim/ipsec.c
blob: 386336a38f349d41692d8564783ec4c5e23f11af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2018 Oracle and/or its affiliates. All rights reserved. */

#include <crypto/aead.h>
#include <linux/debugfs.h>
#include <net/xfrm.h>

#include "netdevsim.h"

#define NSIM_IPSEC_AUTH_BITS	128

static ssize_t nsim_dbg_netdev_ops_read(struct file *filp,
					char __user *buffer,
					size_t count, loff_t *ppos)
{
	struct netdevsim *ns = filp->private_data;
	struct nsim_ipsec *ipsec = &ns->ipsec;
	size_t bufsize;
	char *buf, *p;
	int len;
	int i;

	/* the buffer needed is
	 * (num SAs * 3 lines each * ~60 bytes per line) + one more line
	 */
	bufsize = (ipsec->count * 4 * 60) + 60;
	buf = kzalloc(bufsize, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	p = buf;
	p += scnprintf(p, bufsize - (p - buf),
		       "SA count=%u tx=%u\n",
		       ipsec->count, ipsec->tx);

	for (i = 0; i < NSIM_IPSEC_MAX_SA_COUNT; i++) {
		struct nsim_sa *sap = &ipsec->sa[i];

		if (!sap->used)
			continue;

		p += scnprintf(p, bufsize - (p - buf),
			       "sa[%i] %cx ipaddr=0x%08x %08x %08x %08x\n",
			       i, (sap->rx ? 'r' : 't'), sap->ipaddr[0],
			       sap->ipaddr[1], sap->ipaddr[2], sap->ipaddr[3]);
		p += scnprintf(p, bufsize - (p - buf),
			       "sa[%i]    spi=0x%08x proto=0x%x salt=0x%08x crypt=%d\n",
			       i, be32_to_cpu(sap->xs->id.spi),
			       sap->xs->id.proto, sap->salt, sap->crypt);
		p += scnprintf(p, bufsize - (p - buf),
			       "sa[%i]    key=0x%08x %08x %08x %08x\n",
			       i, sap->key[0], sap->key[1],
			       sap->key[2], sap->key[3]);
	}

	len = simple_read_from_buffer(buffer, count, ppos, buf, p - buf);

	kfree(buf);
	return len;
}

static const struct file_operations ipsec_dbg_fops = {
	.owner = THIS_MODULE,
	.open = simple_open,
	.read = nsim_dbg_netdev_ops_read,
};

static int nsim_ipsec_find_empty_idx(struct nsim_ipsec *ipsec)
{
	u32 i;

	if (ipsec->count == NSIM_IPSEC_MAX_SA_COUNT)
		return -ENOSPC;

	/* search sa table */
	for (i = 0; i < NSIM_IPSEC_MAX_SA_COUNT; i++) {
		if (!ipsec->sa[i].used)
			return i;
	}

	return -ENOSPC;
}

static int nsim_ipsec_parse_proto_keys(struct xfrm_state *xs,
				       u32 *mykey, u32 *mysalt)
{
	const char aes_gcm_name[] = "rfc4106(gcm(aes))";
	struct net_device *dev = xs->xso.real_dev;
	unsigned char *key_data;
	char *alg_name = NULL;
	int key_len;

	if (!xs->aead) {
		netdev_err(dev, "Unsupported IPsec algorithm\n");
		return -EINVAL;
	}

	if (xs->aead->alg_icv_len != NSIM_IPSEC_AUTH_BITS) {
		netdev_err(dev, "IPsec offload requires %d bit authentication\n",
			   NSIM_IPSEC_AUTH_BITS);
		return -EINVAL;
	}

	key_data = &xs->aead->alg_key[0];
	key_len = xs->aead->alg_key_len;
	alg_name = xs->aead->alg_name;

	if (strcmp(alg_name, aes_gcm_name)) {
		netdev_err(dev, "Unsupported IPsec algorithm - please use %s\n",
			   aes_gcm_name);
		return -EINVAL;
	}

	/* 160 accounts for 16 byte key and 4 byte salt */
	if (key_len > NSIM_IPSEC_AUTH_BITS) {
		*mysalt = ((u32 *)key_data)[4];
	} else if (key_len == NSIM_IPSEC_AUTH_BITS) {
		*mysalt = 0;
	} else {
		netdev_err(dev, "IPsec hw offload only supports 128 bit keys with optional 32 bit salt\n");
		return -EINVAL;
	}
	memcpy(mykey, key_data, 16);

	return 0;
}

static int nsim_ipsec_add_sa(struct xfrm_state *xs)
{
	struct nsim_ipsec *ipsec;
	struct net_device *dev;
	struct netdevsim *ns;
	struct nsim_sa sa;
	u16 sa_idx;
	int ret;

	dev = xs->xso.real_dev;
	ns = netdev_priv(dev);
	ipsec = &ns->ipsec;

	if (xs->id.proto != IPPROTO_ESP && xs->id.proto != IPPROTO_AH) {
		netdev_err(dev, "Unsupported protocol 0x%04x for ipsec offload\n",
			   xs->id.proto);
		return -EINVAL;
	}

	if (xs->calg) {
		netdev_err(dev, "Compression offload not supported\n");
		return -EINVAL;
	}

	/* find the first unused index */
	ret = nsim_ipsec_find_empty_idx(ipsec);
	if (ret < 0) {
		netdev_err(dev, "No space for SA in Rx table!\n");
		return ret;
	}
	sa_idx = (u16)ret;

	memset(&sa, 0, sizeof(sa));
	sa.used = true;
	sa.xs = xs;

	if (sa.xs->id.proto & IPPROTO_ESP)
		sa.crypt = xs->ealg || xs->aead;

	/* get the key and salt */
	ret = nsim_ipsec_parse_proto_keys(xs, sa.key, &sa.salt);
	if (ret) {
		netdev_err(dev, "Failed to get key data for SA table\n");
		return ret;
	}

	if (xs->xso.dir == XFRM_DEV_OFFLOAD_IN) {
		sa.rx = true;

		if (xs->props.family == AF_INET6)
			memcpy(sa.ipaddr, &xs->id.daddr.a6, 16);
		else
			memcpy(&sa.ipaddr[3], &xs->id.daddr.a4, 4);
	}

	/* the preparations worked, so save the info */
	memcpy(&ipsec->sa[sa_idx], &sa, sizeof(sa));

	/* the XFRM stack doesn't like offload_handle == 0,
	 * so add a bitflag in case our array index is 0
	 */
	xs->xso.offload_handle = sa_idx | NSIM_IPSEC_VALID;
	ipsec->count++;

	return 0;
}

static void nsim_ipsec_del_sa(struct xfrm_state *xs)
{
	struct netdevsim *ns = netdev_priv(xs->xso.real_dev);
	struct nsim_ipsec *ipsec = &ns->ipsec;
	u16 sa_idx;

	sa_idx = xs->xso.offload_handle & ~NSIM_IPSEC_VALID;
	if (!ipsec->sa[sa_idx].used) {
		netdev_err(ns->netdev, "Invalid SA for delete sa_idx=%d\n",
			   sa_idx);
		return;
	}

	memset(&ipsec->sa[sa_idx], 0, sizeof(struct nsim_sa));
	ipsec->count--;
}

static bool nsim_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
{
	struct netdevsim *ns = netdev_priv(xs->xso.real_dev);
	struct nsim_ipsec *ipsec = &ns->ipsec;

	ipsec->ok++;

	return true;
}

static const struct xfrmdev_ops nsim_xfrmdev_ops = {
	.xdo_dev_state_add	= nsim_ipsec_add_sa,
	.xdo_dev_state_delete	= nsim_ipsec_del_sa,
	.xdo_dev_offload_ok	= nsim_ipsec_offload_ok,
};

bool nsim_ipsec_tx(struct netdevsim *ns, struct sk_buff *skb)
{
	struct sec_path *sp = skb_sec_path(skb);
	struct nsim_ipsec *ipsec = &ns->ipsec;
	struct xfrm_state *xs;
	struct nsim_sa *tsa;
	u32 sa_idx;

	/* do we even need to check this packet? */
	if (!sp)
		return true;

	if (unlikely(!sp->len)) {
		netdev_err(ns->netdev, "no xfrm state len = %d\n",
			   sp->len);
		return false;
	}

	xs = xfrm_input_state(skb);
	if (unlikely(!xs)) {
		netdev_err(ns->netdev, "no xfrm_input_state() xs = %p\n", xs);
		return false;
	}

	sa_idx = xs->xso.offload_handle & ~NSIM_IPSEC_VALID;
	if (unlikely(sa_idx >= NSIM_IPSEC_MAX_SA_COUNT)) {
		netdev_err(ns->netdev, "bad sa_idx=%d max=%d\n",
			   sa_idx, NSIM_IPSEC_MAX_SA_COUNT);
		return false;
	}

	tsa = &ipsec->sa[sa_idx];
	if (unlikely(!tsa->used)) {
		netdev_err(ns->netdev, "unused sa_idx=%d\n", sa_idx);
		return false;
	}

	if (xs->id.proto != IPPROTO_ESP && xs->id.proto != IPPROTO_AH) {
		netdev_err(ns->netdev, "unexpected proto=%d\n", xs->id.proto);
		return false;
	}

	ipsec->tx++;

	return true;
}

void nsim_ipsec_init(struct netdevsim *ns)
{
	ns->netdev->xfrmdev_ops = &nsim_xfrmdev_ops;

#define NSIM_ESP_FEATURES	(NETIF_F_HW_ESP | \
				 NETIF_F_HW_ESP_TX_CSUM | \
				 NETIF_F_GSO_ESP)

	ns->netdev->features |= NSIM_ESP_FEATURES;
	ns->netdev->hw_enc_features |= NSIM_ESP_FEATURES;

	ns->ipsec.pfile = debugfs_create_file("ipsec", 0400,
					      ns->nsim_dev_port->ddir, ns,
					      &ipsec_dbg_fops);
}

void nsim_ipsec_teardown(struct netdevsim *ns)
{
	struct nsim_ipsec *ipsec = &ns->ipsec;

	if (ipsec->count)
		netdev_err(ns->netdev, "tearing down IPsec offload with %d SAs left\n",
			   ipsec->count);
	debugfs_remove_recursive(ipsec->pfile);
}