projects/linux·blob v5.13 · refs

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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * net/psample/psample.c - Netlink channel for packet sampling
4 * Copyright (c) 2017 Yotam Gigi <[email protected]>
5 */
6
7#include <linux/types.h>
8#include <linux/kernel.h>
9#include <linux/skbuff.h>
10#include <linux/module.h>
11#include <linux/timekeeping.h>
12#include <net/net_namespace.h>
13#include <net/sock.h>
14#include <net/netlink.h>
15#include <net/genetlink.h>
16#include <net/psample.h>
17#include <linux/spinlock.h>
18#include <net/ip_tunnels.h>
19#include <net/dst_metadata.h>
20
21#define PSAMPLE_MAX_PACKET_SIZE 0xffff
22
23static LIST_HEAD(psample_groups_list);
24static DEFINE_SPINLOCK(psample_groups_lock);
25
26/* multicast groups */
27enum psample_nl_multicast_groups {
28 PSAMPLE_NL_MCGRP_CONFIG,
29 PSAMPLE_NL_MCGRP_SAMPLE,
30};
31
32static const struct genl_multicast_group psample_nl_mcgrps[] = {
33 [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME },
34 [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME },
35};
36
37static struct genl_family psample_nl_family __ro_after_init;
38
39static int psample_group_nl_fill(struct sk_buff *msg,
40 struct psample_group *group,
41 enum psample_command cmd, u32 portid, u32 seq,
42 int flags)
43{
44 void *hdr;
45 int ret;
46
47 hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd);
48 if (!hdr)
49 return -EMSGSIZE;
50
51 ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
52 if (ret < 0)
53 goto error;
54
55 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount);
56 if (ret < 0)
57 goto error;
58
59 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq);
60 if (ret < 0)
61 goto error;
62
63 genlmsg_end(msg, hdr);
64 return 0;
65
66error:
67 genlmsg_cancel(msg, hdr);
68 return -EMSGSIZE;
69}
70
71static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg,
72 struct netlink_callback *cb)
73{
74 struct psample_group *group;
75 int start = cb->args[0];
76 int idx = 0;
77 int err;
78
79 spin_lock_bh(&psample_groups_lock);
80 list_for_each_entry(group, &psample_groups_list, list) {
81 if (!net_eq(group->net, sock_net(msg->sk)))
82 continue;
83 if (idx < start) {
84 idx++;
85 continue;
86 }
87 err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP,
88 NETLINK_CB(cb->skb).portid,
89 cb->nlh->nlmsg_seq, NLM_F_MULTI);
90 if (err)
91 break;
92 idx++;
93 }
94
95 spin_unlock_bh(&psample_groups_lock);
96 cb->args[0] = idx;
97 return msg->len;
98}
99
100static const struct genl_small_ops psample_nl_ops[] = {
101 {
102 .cmd = PSAMPLE_CMD_GET_GROUP,
103 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
104 .dumpit = psample_nl_cmd_get_group_dumpit,
105 /* can be retrieved by unprivileged users */
106 }
107};
108
109static struct genl_family psample_nl_family __ro_after_init = {
110 .name = PSAMPLE_GENL_NAME,
111 .version = PSAMPLE_GENL_VERSION,
112 .maxattr = PSAMPLE_ATTR_MAX,
113 .netnsok = true,
114 .module = THIS_MODULE,
115 .mcgrps = psample_nl_mcgrps,
116 .small_ops = psample_nl_ops,
117 .n_small_ops = ARRAY_SIZE(psample_nl_ops),
118 .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps),
119};
120
121static void psample_group_notify(struct psample_group *group,
122 enum psample_command cmd)
123{
124 struct sk_buff *msg;
125 int err;
126
127 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
128 if (!msg)
129 return;
130
131 err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
132 if (!err)
133 genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
134 PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
135 else
136 nlmsg_free(msg);
137}
138
139static struct psample_group *psample_group_create(struct net *net,
140 u32 group_num)
141{
142 struct psample_group *group;
143
144 group = kzalloc(sizeof(*group), GFP_ATOMIC);
145 if (!group)
146 return NULL;
147
148 group->net = net;
149 group->group_num = group_num;
150 list_add_tail(&group->list, &psample_groups_list);
151
152 psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
153 return group;
154}
155
156static void psample_group_destroy(struct psample_group *group)
157{
158 psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
159 list_del(&group->list);
160 kfree_rcu(group, rcu);
161}
162
163static struct psample_group *
164psample_group_lookup(struct net *net, u32 group_num)
165{
166 struct psample_group *group;
167
168 list_for_each_entry(group, &psample_groups_list, list)
169 if ((group->group_num == group_num) && (group->net == net))
170 return group;
171 return NULL;
172}
173
174struct psample_group *psample_group_get(struct net *net, u32 group_num)
175{
176 struct psample_group *group;
177
178 spin_lock_bh(&psample_groups_lock);
179
180 group = psample_group_lookup(net, group_num);
181 if (!group) {
182 group = psample_group_create(net, group_num);
183 if (!group)
184 goto out;
185 }
186 group->refcount++;
187
188out:
189 spin_unlock_bh(&psample_groups_lock);
190 return group;
191}
192EXPORT_SYMBOL_GPL(psample_group_get);
193
194void psample_group_take(struct psample_group *group)
195{
196 spin_lock_bh(&psample_groups_lock);
197 group->refcount++;
198 spin_unlock_bh(&psample_groups_lock);
199}
200EXPORT_SYMBOL_GPL(psample_group_take);
201
202void psample_group_put(struct psample_group *group)
203{
204 spin_lock_bh(&psample_groups_lock);
205
206 if (--group->refcount == 0)
207 psample_group_destroy(group);
208
209 spin_unlock_bh(&psample_groups_lock);
210}
211EXPORT_SYMBOL_GPL(psample_group_put);
212
213#ifdef CONFIG_INET
214static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
215 struct ip_tunnel_info *tun_info)
216{
217 unsigned short tun_proto = ip_tunnel_info_af(tun_info);
218 const void *tun_opts = ip_tunnel_info_opts(tun_info);
219 const struct ip_tunnel_key *tun_key = &tun_info->key;
220 int tun_opts_len = tun_info->options_len;
221
222 if (tun_key->tun_flags & TUNNEL_KEY &&
223 nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
224 PSAMPLE_TUNNEL_KEY_ATTR_PAD))
225 return -EMSGSIZE;
226
227 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
228 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
229 return -EMSGSIZE;
230
231 switch (tun_proto) {
232 case AF_INET:
233 if (tun_key->u.ipv4.src &&
234 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
235 tun_key->u.ipv4.src))
236 return -EMSGSIZE;
237 if (tun_key->u.ipv4.dst &&
238 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
239 tun_key->u.ipv4.dst))
240 return -EMSGSIZE;
241 break;
242 case AF_INET6:
243 if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
244 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
245 &tun_key->u.ipv6.src))
246 return -EMSGSIZE;
247 if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
248 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
249 &tun_key->u.ipv6.dst))
250 return -EMSGSIZE;
251 break;
252 }
253 if (tun_key->tos &&
254 nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
255 return -EMSGSIZE;
256 if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
257 return -EMSGSIZE;
258 if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) &&
259 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
260 return -EMSGSIZE;
261 if ((tun_key->tun_flags & TUNNEL_CSUM) &&
262 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
263 return -EMSGSIZE;
264 if (tun_key->tp_src &&
265 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
266 return -EMSGSIZE;
267 if (tun_key->tp_dst &&
268 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
269 return -EMSGSIZE;
270 if ((tun_key->tun_flags & TUNNEL_OAM) &&
271 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
272 return -EMSGSIZE;
273 if (tun_opts_len) {
274 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT &&
275 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
276 tun_opts_len, tun_opts))
277 return -EMSGSIZE;
278 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT &&
279 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
280 tun_opts_len, tun_opts))
281 return -EMSGSIZE;
282 }
283
284 return 0;
285}
286
287static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
288 struct ip_tunnel_info *tun_info)
289{
290 struct nlattr *nla;
291 int err;
292
293 nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
294 if (!nla)
295 return -EMSGSIZE;
296
297 err = __psample_ip_tun_to_nlattr(skb, tun_info);
298 if (err) {
299 nla_nest_cancel(skb, nla);
300 return err;
301 }
302
303 nla_nest_end(skb, nla);
304
305 return 0;
306}
307
308static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
309{
310 unsigned short tun_proto = ip_tunnel_info_af(tun_info);
311 const struct ip_tunnel_key *tun_key = &tun_info->key;
312 int tun_opts_len = tun_info->options_len;
313 int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */
314
315 if (tun_key->tun_flags & TUNNEL_KEY)
316 sum += nla_total_size_64bit(sizeof(u64));
317
318 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
319 sum += nla_total_size(0);
320
321 switch (tun_proto) {
322 case AF_INET:
323 if (tun_key->u.ipv4.src)
324 sum += nla_total_size(sizeof(u32));
325 if (tun_key->u.ipv4.dst)
326 sum += nla_total_size(sizeof(u32));
327 break;
328 case AF_INET6:
329 if (!ipv6_addr_any(&tun_key->u.ipv6.src))
330 sum += nla_total_size(sizeof(struct in6_addr));
331 if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
332 sum += nla_total_size(sizeof(struct in6_addr));
333 break;
334 }
335 if (tun_key->tos)
336 sum += nla_total_size(sizeof(u8));
337 sum += nla_total_size(sizeof(u8)); /* TTL */
338 if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT)
339 sum += nla_total_size(0);
340 if (tun_key->tun_flags & TUNNEL_CSUM)
341 sum += nla_total_size(0);
342 if (tun_key->tp_src)
343 sum += nla_total_size(sizeof(u16));
344 if (tun_key->tp_dst)
345 sum += nla_total_size(sizeof(u16));
346 if (tun_key->tun_flags & TUNNEL_OAM)
347 sum += nla_total_size(0);
348 if (tun_opts_len) {
349 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT)
350 sum += nla_total_size(tun_opts_len);
351 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT)
352 sum += nla_total_size(tun_opts_len);
353 }
354
355 return sum;
356}
357#endif
358
359void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
360 u32 sample_rate, const struct psample_metadata *md)
361{
362 ktime_t tstamp = ktime_get_real();
363 int out_ifindex = md->out_ifindex;
364 int in_ifindex = md->in_ifindex;
365 u32 trunc_size = md->trunc_size;
366#ifdef CONFIG_INET
367 struct ip_tunnel_info *tun_info;
368#endif
369 struct sk_buff *nl_skb;
370 int data_len;
371 int meta_len;
372 void *data;
373 int ret;
374
375 meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
376 (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
377 (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +
378 (md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
379 (md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
380 nla_total_size(sizeof(u32)) + /* sample_rate */
381 nla_total_size(sizeof(u32)) + /* orig_size */
382 nla_total_size(sizeof(u32)) + /* group_num */
383 nla_total_size(sizeof(u32)) + /* seq */
384 nla_total_size_64bit(sizeof(u64)) + /* timestamp */
385 nla_total_size(sizeof(u16)); /* protocol */
386
387#ifdef CONFIG_INET
388 tun_info = skb_tunnel_info(skb);
389 if (tun_info)
390 meta_len += psample_tunnel_meta_len(tun_info);
391#endif
392
393 data_len = min(skb->len, trunc_size);
394 if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
395 data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
396 - NLA_ALIGNTO;
397
398 nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
399 if (unlikely(!nl_skb))
400 return;
401
402 data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
403 PSAMPLE_CMD_SAMPLE);
404 if (unlikely(!data))
405 goto error;
406
407 if (in_ifindex) {
408 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
409 if (unlikely(ret < 0))
410 goto error;
411 }
412
413 if (out_ifindex) {
414 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
415 if (unlikely(ret < 0))
416 goto error;
417 }
418
419 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
420 if (unlikely(ret < 0))
421 goto error;
422
423 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
424 if (unlikely(ret < 0))
425 goto error;
426
427 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
428 if (unlikely(ret < 0))
429 goto error;
430
431 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
432 if (unlikely(ret < 0))
433 goto error;
434
435 if (md->out_tc_valid) {
436 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc);
437 if (unlikely(ret < 0))
438 goto error;
439 }
440
441 if (md->out_tc_occ_valid) {
442 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC,
443 md->out_tc_occ, PSAMPLE_ATTR_PAD);
444 if (unlikely(ret < 0))
445 goto error;
446 }
447
448 if (md->latency_valid) {
449 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY,
450 md->latency, PSAMPLE_ATTR_PAD);
451 if (unlikely(ret < 0))
452 goto error;
453 }
454
455 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP,
456 ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD);
457 if (unlikely(ret < 0))
458 goto error;
459
460 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO,
461 be16_to_cpu(skb->protocol));
462 if (unlikely(ret < 0))
463 goto error;
464
465 if (data_len) {
466 int nla_len = nla_total_size(data_len);
467 struct nlattr *nla;
468
469 nla = skb_put(nl_skb, nla_len);
470 nla->nla_type = PSAMPLE_ATTR_DATA;
471 nla->nla_len = nla_attr_size(data_len);
472
473 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
474 goto error;
475 }
476
477#ifdef CONFIG_INET
478 if (tun_info) {
479 ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
480 if (unlikely(ret < 0))
481 goto error;
482 }
483#endif
484
485 genlmsg_end(nl_skb, data);
486 genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
487 PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
488
489 return;
490error:
491 pr_err_ratelimited("Could not create psample log message\n");
492 nlmsg_free(nl_skb);
493}
494EXPORT_SYMBOL_GPL(psample_sample_packet);
495
496static int __init psample_module_init(void)
497{
498 return genl_register_family(&psample_nl_family);
499}
500
501static void __exit psample_module_exit(void)
502{
503 genl_unregister_family(&psample_nl_family);
504}
505
506module_init(psample_module_init);
507module_exit(psample_module_exit);
508
509MODULE_AUTHOR("Yotam Gigi <[email protected]>");
510MODULE_DESCRIPTION("netlink channel for packet sampling");
511MODULE_LICENSE("GPL v2");