aboutsummaryrefslogtreecommitdiff
path: root/net/psample/psample.c
blob: 33e238c965bd89366a90a6f0ad82d183449595b6 (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
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
// SPDX-License-Identifier: GPL-2.0-only
/*
 * net/psample/psample.c - Netlink channel for packet sampling
 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com>
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/genetlink.h>
#include <net/psample.h>
#include <linux/spinlock.h>
#include <net/ip_tunnels.h>
#include <net/dst_metadata.h>

#define PSAMPLE_MAX_PACKET_SIZE 0xffff

static LIST_HEAD(psample_groups_list);
static DEFINE_SPINLOCK(psample_groups_lock);

/* multicast groups */
enum psample_nl_multicast_groups {
	PSAMPLE_NL_MCGRP_CONFIG,
	PSAMPLE_NL_MCGRP_SAMPLE,
};

static const struct genl_multicast_group psample_nl_mcgrps[] = {
	[PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
	[PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
};

static struct genl_family psample_nl_family __ro_after_init;

static int psample_group_nl_fill(struct sk_buff *msg,
				 struct psample_group *group,
				 enum psample_command cmd, u32 portid, u32 seq,
				 int flags)
{
	void *hdr;
	int ret;

	hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
	if (!hdr)
		return -EMSGSIZE;

	ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
	if (ret < 0)
		goto error;

	ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
	if (ret < 0)
		goto error;

	ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
	if (ret < 0)
		goto error;

	genlmsg_end(msg, hdr);
	return 0;

error:
	genlmsg_cancel(msg, hdr);
	return -EMSGSIZE;
}

static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
					   struct netlink_callback *cb)
{
	struct psample_group *group;
	int start = cb->args[0];
	int idx = 0;
	int err;

	spin_lock_bh(&psample_groups_lock);
	list_for_each_entry(group, &psample_groups_list, list) {
		if (!net_eq(group->net, sock_net(msg->sk)))
			continue;
		if (idx < start) {
			idx++;
			continue;
		}
		err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
					    NETLINK_CB(cb->skb).portid,
					    cb->nlh->nlmsg_seq, NLM_F_MULTI);
		if (err)
			break;
		idx++;
	}

	spin_unlock_bh(&psample_groups_lock);
	cb->args[0] = idx;
	return msg->len;
}

static const struct genl_small_ops psample_nl_ops[] = {
	{
		.cmd = PSAMPLE_CMD_GET_GROUP,
		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
		.dumpit = psample_nl_cmd_get_group_dumpit,
		/* can be retrieved by unprivileged users */
	}
};

static struct genl_family psample_nl_family __ro_after_init = {
	.name		= PSAMPLE_GENL_NAME,
	.version	= PSAMPLE_GENL_VERSION,
	.maxattr	= PSAMPLE_ATTR_MAX,
	.netnsok	= true,
	.module		= THIS_MODULE,
	.mcgrps		= psample_nl_mcgrps,
	.small_ops	= psample_nl_ops,
	.n_small_ops	= ARRAY_SIZE(psample_nl_ops),
	.n_mcgrps	= ARRAY_SIZE(psample_nl_mcgrps),
};

static void psample_group_notify(struct psample_group *group,
				 enum psample_command cmd)
{
	struct sk_buff *msg;
	int err;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (!msg)
		return;

	err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
	if (!err)
		genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
					PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
	else
		nlmsg_free(msg);
}

static struct psample_group *psample_group_create(struct net *net,
						  u32 group_num)
{
	struct psample_group *group;

	group = kzalloc(sizeof(*group), GFP_ATOMIC);
	if (!group)
		return NULL;

	group->net = net;
	group->group_num = group_num;
	list_add_tail(&group->list, &psample_groups_list);

	psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
	return group;
}

static void psample_group_destroy(struct psample_group *group)
{
	psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
	list_del(&group->list);
	kfree_rcu(group, rcu);
}

static struct psample_group *
psample_group_lookup(struct net *net, u32 group_num)
{
	struct psample_group *group;

	list_for_each_entry(group, &psample_groups_list, list)
		if ((group->group_num == group_num) && (group->net == net))
			return group;
	return NULL;
}

struct psample_group *psample_group_get(struct net *net, u32 group_num)
{
	struct psample_group *group;

	spin_lock_bh(&psample_groups_lock);

	group = psample_group_lookup(net, group_num);
	if (!group) {
		group = psample_group_create(net, group_num);
		if (!group)
			goto out;
	}
	group->refcount++;

out:
	spin_unlock_bh(&psample_groups_lock);
	return group;
}
EXPORT_SYMBOL_GPL(psample_group_get);

void psample_group_take(struct psample_group *group)
{
	spin_lock_bh(&psample_groups_lock);
	group->refcount++;
	spin_unlock_bh(&psample_groups_lock);
}
EXPORT_SYMBOL_GPL(psample_group_take);

void psample_group_put(struct psample_group *group)
{
	spin_lock_bh(&psample_groups_lock);

	if (--group->refcount == 0)
		psample_group_destroy(group);

	spin_unlock_bh(&psample_groups_lock);
}
EXPORT_SYMBOL_GPL(psample_group_put);

#ifdef CONFIG_INET
static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
			      struct ip_tunnel_info *tun_info)
{
	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
	const void *tun_opts = ip_tunnel_info_opts(tun_info);
	const struct ip_tunnel_key *tun_key = &tun_info->key;
	int tun_opts_len = tun_info->options_len;

	if (tun_key->tun_flags & TUNNEL_KEY &&
	    nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
			 PSAMPLE_TUNNEL_KEY_ATTR_PAD))
		return -EMSGSIZE;

	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
		return -EMSGSIZE;

	switch (tun_proto) {
	case AF_INET:
		if (tun_key->u.ipv4.src &&
		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
				    tun_key->u.ipv4.src))
			return -EMSGSIZE;
		if (tun_key->u.ipv4.dst &&
		    nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
				    tun_key->u.ipv4.dst))
			return -EMSGSIZE;
		break;
	case AF_INET6:
		if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
				     &tun_key->u.ipv6.src))
			return -EMSGSIZE;
		if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
		    nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
				     &tun_key->u.ipv6.dst))
			return -EMSGSIZE;
		break;
	}
	if (tun_key->tos &&
	    nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
		return -EMSGSIZE;
	if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
		return -EMSGSIZE;
	if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) &&
	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
		return -EMSGSIZE;
	if ((tun_key->tun_flags & TUNNEL_CSUM) &&
	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
		return -EMSGSIZE;
	if (tun_key->tp_src &&
	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
		return -EMSGSIZE;
	if (tun_key->tp_dst &&
	    nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
		return -EMSGSIZE;
	if ((tun_key->tun_flags & TUNNEL_OAM) &&
	    nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
		return -EMSGSIZE;
	if (tun_opts_len) {
		if (tun_key->tun_flags & TUNNEL_GENEVE_OPT &&
		    nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
			    tun_opts_len, tun_opts))
			return -EMSGSIZE;
		else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT &&
			 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
				 tun_opts_len, tun_opts))
			return -EMSGSIZE;
	}

	return 0;
}

static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
			    struct ip_tunnel_info *tun_info)
{
	struct nlattr *nla;
	int err;

	nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
	if (!nla)
		return -EMSGSIZE;

	err = __psample_ip_tun_to_nlattr(skb, tun_info);
	if (err) {
		nla_nest_cancel(skb, nla);
		return err;
	}

	nla_nest_end(skb, nla);

	return 0;
}

static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
{
	unsigned short tun_proto = ip_tunnel_info_af(tun_info);
	const struct ip_tunnel_key *tun_key = &tun_info->key;
	int tun_opts_len = tun_info->options_len;
	int sum = 0;

	if (tun_key->tun_flags & TUNNEL_KEY)
		sum += nla_total_size(sizeof(u64));

	if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
		sum += nla_total_size(0);

	switch (tun_proto) {
	case AF_INET:
		if (tun_key->u.ipv4.src)
			sum += nla_total_size(sizeof(u32));
		if (tun_key->u.ipv4.dst)
			sum += nla_total_size(sizeof(u32));
		break;
	case AF_INET6:
		if (!ipv6_addr_any(&tun_key->u.ipv6.src))
			sum += nla_total_size(sizeof(struct in6_addr));
		if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
			sum += nla_total_size(sizeof(struct in6_addr));
		break;
	}
	if (tun_key->tos)
		sum += nla_total_size(sizeof(u8));
	sum += nla_total_size(sizeof(u8));	/* TTL */
	if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT)
		sum += nla_total_size(0);
	if (tun_key->tun_flags & TUNNEL_CSUM)
		sum += nla_total_size(0);
	if (tun_key->tp_src)
		sum += nla_total_size(sizeof(u16));
	if (tun_key->tp_dst)
		sum += nla_total_size(sizeof(u16));
	if (tun_key->tun_flags & TUNNEL_OAM)
		sum += nla_total_size(0);
	if (tun_opts_len) {
		if (tun_key->tun_flags & TUNNEL_GENEVE_OPT)
			sum += nla_total_size(tun_opts_len);
		else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT)
			sum += nla_total_size(tun_opts_len);
	}

	return sum;
}
#endif

void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
			   u32 trunc_size, int in_ifindex, int out_ifindex,
			   u32 sample_rate)
{
#ifdef CONFIG_INET
	struct ip_tunnel_info *tun_info;
#endif
	struct sk_buff *nl_skb;
	int data_len;
	int meta_len;
	void *data;
	int ret;

	meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
		   (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
		   nla_total_size(sizeof(u32)) +	/* sample_rate */
		   nla_total_size(sizeof(u32)) +	/* orig_size */
		   nla_total_size(sizeof(u32)) +	/* group_num */
		   nla_total_size(sizeof(u32));		/* seq */

#ifdef CONFIG_INET
	tun_info = skb_tunnel_info(skb);
	if (tun_info)
		meta_len += psample_tunnel_meta_len(tun_info);
#endif

	data_len = min(skb->len, trunc_size);
	if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
		data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
			    - NLA_ALIGNTO;

	nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
	if (unlikely(!nl_skb))
		return;

	data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
			   PSAMPLE_CMD_SAMPLE);
	if (unlikely(!data))
		goto error;

	if (in_ifindex) {
		ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
		if (unlikely(ret < 0))
			goto error;
	}

	if (out_ifindex) {
		ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
		if (unlikely(ret < 0))
			goto error;
	}

	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
	if (unlikely(ret < 0))
		goto error;

	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
	if (unlikely(ret < 0))
		goto error;

	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
	if (unlikely(ret < 0))
		goto error;

	ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
	if (unlikely(ret < 0))
		goto error;

	if (data_len) {
		int nla_len = nla_total_size(data_len);
		struct nlattr *nla;

		nla = skb_put(nl_skb, nla_len);
		nla->nla_type = PSAMPLE_ATTR_DATA;
		nla->nla_len = nla_attr_size(data_len);

		if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
			goto error;
	}

#ifdef CONFIG_INET
	if (tun_info) {
		ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
		if (unlikely(ret < 0))
			goto error;
	}
#endif

	genlmsg_end(nl_skb, data);
	genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
				PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);

	return;
error:
	pr_err_ratelimited("Could not create psample log message\n");
	nlmsg_free(nl_skb);
}
EXPORT_SYMBOL_GPL(psample_sample_packet);

static int __init psample_module_init(void)
{
	return genl_register_family(&psample_nl_family);
}

static void __exit psample_module_exit(void)
{
	genl_unregister_family(&psample_nl_family);
}

module_init(psample_module_init);
module_exit(psample_module_exit);

MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>");
MODULE_DESCRIPTION("netlink channel for packet sampling");
MODULE_LICENSE("GPL v2");