projects/linux·blob v6.1 · 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 .resv_start_op = PSAMPLE_CMD_GET_GROUP + 1,
119 .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps),
120};
121
122static void psample_group_notify(struct psample_group *group,
123 enum psample_command cmd)
124{
125 struct sk_buff *msg;
126 int err;
127
128 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
129 if (!msg)
130 return;
131
132 err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI);
133 if (!err)
134 genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0,
135 PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC);
136 else
137 nlmsg_free(msg);
138}
139
140static struct psample_group *psample_group_create(struct net *net,
141 u32 group_num)
142{
143 struct psample_group *group;
144
145 group = kzalloc(sizeof(*group), GFP_ATOMIC);
146 if (!group)
147 return NULL;
148
149 group->net = net;
150 group->group_num = group_num;
151 list_add_tail(&group->list, &psample_groups_list);
152
153 psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP);
154 return group;
155}
156
157static void psample_group_destroy(struct psample_group *group)
158{
159 psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
160 list_del(&group->list);
161 kfree_rcu(group, rcu);
162}
163
164static struct psample_group *
165psample_group_lookup(struct net *net, u32 group_num)
166{
167 struct psample_group *group;
168
169 list_for_each_entry(group, &psample_groups_list, list)
170 if ((group->group_num == group_num) && (group->net == net))
171 return group;
172 return NULL;
173}
174
175struct psample_group *psample_group_get(struct net *net, u32 group_num)
176{
177 struct psample_group *group;
178
179 spin_lock_bh(&psample_groups_lock);
180
181 group = psample_group_lookup(net, group_num);
182 if (!group) {
183 group = psample_group_create(net, group_num);
184 if (!group)
185 goto out;
186 }
187 group->refcount++;
188
189out:
190 spin_unlock_bh(&psample_groups_lock);
191 return group;
192}
193EXPORT_SYMBOL_GPL(psample_group_get);
194
195void psample_group_take(struct psample_group *group)
196{
197 spin_lock_bh(&psample_groups_lock);
198 group->refcount++;
199 spin_unlock_bh(&psample_groups_lock);
200}
201EXPORT_SYMBOL_GPL(psample_group_take);
202
203void psample_group_put(struct psample_group *group)
204{
205 spin_lock_bh(&psample_groups_lock);
206
207 if (--group->refcount == 0)
208 psample_group_destroy(group);
209
210 spin_unlock_bh(&psample_groups_lock);
211}
212EXPORT_SYMBOL_GPL(psample_group_put);
213
214#ifdef CONFIG_INET
215static int __psample_ip_tun_to_nlattr(struct sk_buff *skb,
216 struct ip_tunnel_info *tun_info)
217{
218 unsigned short tun_proto = ip_tunnel_info_af(tun_info);
219 const void *tun_opts = ip_tunnel_info_opts(tun_info);
220 const struct ip_tunnel_key *tun_key = &tun_info->key;
221 int tun_opts_len = tun_info->options_len;
222
223 if (tun_key->tun_flags & TUNNEL_KEY &&
224 nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id,
225 PSAMPLE_TUNNEL_KEY_ATTR_PAD))
226 return -EMSGSIZE;
227
228 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE &&
229 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE))
230 return -EMSGSIZE;
231
232 switch (tun_proto) {
233 case AF_INET:
234 if (tun_key->u.ipv4.src &&
235 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC,
236 tun_key->u.ipv4.src))
237 return -EMSGSIZE;
238 if (tun_key->u.ipv4.dst &&
239 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST,
240 tun_key->u.ipv4.dst))
241 return -EMSGSIZE;
242 break;
243 case AF_INET6:
244 if (!ipv6_addr_any(&tun_key->u.ipv6.src) &&
245 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC,
246 &tun_key->u.ipv6.src))
247 return -EMSGSIZE;
248 if (!ipv6_addr_any(&tun_key->u.ipv6.dst) &&
249 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST,
250 &tun_key->u.ipv6.dst))
251 return -EMSGSIZE;
252 break;
253 }
254 if (tun_key->tos &&
255 nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos))
256 return -EMSGSIZE;
257 if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl))
258 return -EMSGSIZE;
259 if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) &&
260 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT))
261 return -EMSGSIZE;
262 if ((tun_key->tun_flags & TUNNEL_CSUM) &&
263 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM))
264 return -EMSGSIZE;
265 if (tun_key->tp_src &&
266 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src))
267 return -EMSGSIZE;
268 if (tun_key->tp_dst &&
269 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst))
270 return -EMSGSIZE;
271 if ((tun_key->tun_flags & TUNNEL_OAM) &&
272 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM))
273 return -EMSGSIZE;
274 if (tun_opts_len) {
275 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT &&
276 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS,
277 tun_opts_len, tun_opts))
278 return -EMSGSIZE;
279 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT &&
280 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS,
281 tun_opts_len, tun_opts))
282 return -EMSGSIZE;
283 }
284
285 return 0;
286}
287
288static int psample_ip_tun_to_nlattr(struct sk_buff *skb,
289 struct ip_tunnel_info *tun_info)
290{
291 struct nlattr *nla;
292 int err;
293
294 nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL);
295 if (!nla)
296 return -EMSGSIZE;
297
298 err = __psample_ip_tun_to_nlattr(skb, tun_info);
299 if (err) {
300 nla_nest_cancel(skb, nla);
301 return err;
302 }
303
304 nla_nest_end(skb, nla);
305
306 return 0;
307}
308
309static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info)
310{
311 unsigned short tun_proto = ip_tunnel_info_af(tun_info);
312 const struct ip_tunnel_key *tun_key = &tun_info->key;
313 int tun_opts_len = tun_info->options_len;
314 int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */
315
316 if (tun_key->tun_flags & TUNNEL_KEY)
317 sum += nla_total_size_64bit(sizeof(u64));
318
319 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE)
320 sum += nla_total_size(0);
321
322 switch (tun_proto) {
323 case AF_INET:
324 if (tun_key->u.ipv4.src)
325 sum += nla_total_size(sizeof(u32));
326 if (tun_key->u.ipv4.dst)
327 sum += nla_total_size(sizeof(u32));
328 break;
329 case AF_INET6:
330 if (!ipv6_addr_any(&tun_key->u.ipv6.src))
331 sum += nla_total_size(sizeof(struct in6_addr));
332 if (!ipv6_addr_any(&tun_key->u.ipv6.dst))
333 sum += nla_total_size(sizeof(struct in6_addr));
334 break;
335 }
336 if (tun_key->tos)
337 sum += nla_total_size(sizeof(u8));
338 sum += nla_total_size(sizeof(u8)); /* TTL */
339 if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT)
340 sum += nla_total_size(0);
341 if (tun_key->tun_flags & TUNNEL_CSUM)
342 sum += nla_total_size(0);
343 if (tun_key->tp_src)
344 sum += nla_total_size(sizeof(u16));
345 if (tun_key->tp_dst)
346 sum += nla_total_size(sizeof(u16));
347 if (tun_key->tun_flags & TUNNEL_OAM)
348 sum += nla_total_size(0);
349 if (tun_opts_len) {
350 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT)
351 sum += nla_total_size(tun_opts_len);
352 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT)
353 sum += nla_total_size(tun_opts_len);
354 }
355
356 return sum;
357}
358#endif
359
360void psample_sample_packet(struct psample_group *group, struct sk_buff *skb,
361 u32 sample_rate, const struct psample_metadata *md)
362{
363 ktime_t tstamp = ktime_get_real();
364 int out_ifindex = md->out_ifindex;
365 int in_ifindex = md->in_ifindex;
366 u32 trunc_size = md->trunc_size;
367#ifdef CONFIG_INET
368 struct ip_tunnel_info *tun_info;
369#endif
370 struct sk_buff *nl_skb;
371 int data_len;
372 int meta_len;
373 void *data;
374 int ret;
375
376 meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) +
377 (out_ifindex ? nla_total_size(sizeof(u16)) : 0) +
378 (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) +
379 (md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
380 (md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) +
381 nla_total_size(sizeof(u32)) + /* sample_rate */
382 nla_total_size(sizeof(u32)) + /* orig_size */
383 nla_total_size(sizeof(u32)) + /* group_num */
384 nla_total_size(sizeof(u32)) + /* seq */
385 nla_total_size_64bit(sizeof(u64)) + /* timestamp */
386 nla_total_size(sizeof(u16)); /* protocol */
387
388#ifdef CONFIG_INET
389 tun_info = skb_tunnel_info(skb);
390 if (tun_info)
391 meta_len += psample_tunnel_meta_len(tun_info);
392#endif
393
394 data_len = min(skb->len, trunc_size);
395 if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE)
396 data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN
397 - NLA_ALIGNTO;
398
399 nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC);
400 if (unlikely(!nl_skb))
401 return;
402
403 data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0,
404 PSAMPLE_CMD_SAMPLE);
405 if (unlikely(!data))
406 goto error;
407
408 if (in_ifindex) {
409 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex);
410 if (unlikely(ret < 0))
411 goto error;
412 }
413
414 if (out_ifindex) {
415 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex);
416 if (unlikely(ret < 0))
417 goto error;
418 }
419
420 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate);
421 if (unlikely(ret < 0))
422 goto error;
423
424 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len);
425 if (unlikely(ret < 0))
426 goto error;
427
428 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num);
429 if (unlikely(ret < 0))
430 goto error;
431
432 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++);
433 if (unlikely(ret < 0))
434 goto error;
435
436 if (md->out_tc_valid) {
437 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc);
438 if (unlikely(ret < 0))
439 goto error;
440 }
441
442 if (md->out_tc_occ_valid) {
443 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC,
444 md->out_tc_occ, PSAMPLE_ATTR_PAD);
445 if (unlikely(ret < 0))
446 goto error;
447 }
448
449 if (md->latency_valid) {
450 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY,
451 md->latency, PSAMPLE_ATTR_PAD);
452 if (unlikely(ret < 0))
453 goto error;
454 }
455
456 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP,
457 ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD);
458 if (unlikely(ret < 0))
459 goto error;
460
461 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO,
462 be16_to_cpu(skb->protocol));
463 if (unlikely(ret < 0))
464 goto error;
465
466 if (data_len) {
467 int nla_len = nla_total_size(data_len);
468 struct nlattr *nla;
469
470 nla = skb_put(nl_skb, nla_len);
471 nla->nla_type = PSAMPLE_ATTR_DATA;
472 nla->nla_len = nla_attr_size(data_len);
473
474 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
475 goto error;
476 }
477
478#ifdef CONFIG_INET
479 if (tun_info) {
480 ret = psample_ip_tun_to_nlattr(nl_skb, tun_info);
481 if (unlikely(ret < 0))
482 goto error;
483 }
484#endif
485
486 genlmsg_end(nl_skb, data);
487 genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0,
488 PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC);
489
490 return;
491error:
492 pr_err_ratelimited("Could not create psample log message\n");
493 nlmsg_free(nl_skb);
494}
495EXPORT_SYMBOL_GPL(psample_sample_packet);
496
497static int __init psample_module_init(void)
498{
499 return genl_register_family(&psample_nl_family);
500}
501
502static void __exit psample_module_exit(void)
503{
504 genl_unregister_family(&psample_nl_family);
505}
506
507module_init(psample_module_init);
508module_exit(psample_module_exit);
509
510MODULE_AUTHOR("Yotam Gigi <[email protected]>");
511MODULE_DESCRIPTION("netlink channel for packet sampling");
512MODULE_LICENSE("GPL v2");