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1/*
2 * Copyright (c) 2017 Nicira, Inc.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 */
8
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/if.h>
12#include <linux/skbuff.h>
13#include <linux/ip.h>
14#include <linux/kernel.h>
15#include <linux/openvswitch.h>
16#include <linux/netlink.h>
17#include <linux/rculist.h>
18
19#include <net/netlink.h>
20#include <net/genetlink.h>
21
22#include "datapath.h"
23#include "meter.h"
24
25#define METER_HASH_BUCKETS 1024
26
27static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
28 [OVS_METER_ATTR_ID] = { .type = NLA_U32, },
29 [OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG },
30 [OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
31 [OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED },
32 [OVS_METER_ATTR_USED] = { .type = NLA_U64 },
33 [OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG },
34 [OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 },
35 [OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 },
36};
37
38static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = {
39 [OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, },
40 [OVS_BAND_ATTR_RATE] = { .type = NLA_U32, },
41 [OVS_BAND_ATTR_BURST] = { .type = NLA_U32, },
42 [OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
43};
44
45static void ovs_meter_free(struct dp_meter *meter)
46{
47 if (!meter)
48 return;
49
50 kfree_rcu(meter, rcu);
51}
52
53static struct hlist_head *meter_hash_bucket(const struct datapath *dp,
54 u32 meter_id)
55{
56 return &dp->meters[meter_id & (METER_HASH_BUCKETS - 1)];
57}
58
59/* Call with ovs_mutex or RCU read lock. */
60static struct dp_meter *lookup_meter(const struct datapath *dp,
61 u32 meter_id)
62{
63 struct dp_meter *meter;
64 struct hlist_head *head;
65
66 head = meter_hash_bucket(dp, meter_id);
67 hlist_for_each_entry_rcu(meter, head, dp_hash_node) {
68 if (meter->id == meter_id)
69 return meter;
70 }
71 return NULL;
72}
73
74static void attach_meter(struct datapath *dp, struct dp_meter *meter)
75{
76 struct hlist_head *head = meter_hash_bucket(dp, meter->id);
77
78 hlist_add_head_rcu(&meter->dp_hash_node, head);
79}
80
81static void detach_meter(struct dp_meter *meter)
82{
83 ASSERT_OVSL();
84 if (meter)
85 hlist_del_rcu(&meter->dp_hash_node);
86}
87
88static struct sk_buff *
89ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd,
90 struct ovs_header **ovs_reply_header)
91{
92 struct sk_buff *skb;
93 struct ovs_header *ovs_header = info->userhdr;
94
95 skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
96 if (!skb)
97 return ERR_PTR(-ENOMEM);
98
99 *ovs_reply_header = genlmsg_put(skb, info->snd_portid,
100 info->snd_seq,
101 &dp_meter_genl_family, 0, cmd);
102 if (!*ovs_reply_header) {
103 nlmsg_free(skb);
104 return ERR_PTR(-EMSGSIZE);
105 }
106 (*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex;
107
108 return skb;
109}
110
111static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id,
112 struct dp_meter *meter)
113{
114 struct nlattr *nla;
115 struct dp_meter_band *band;
116 u16 i;
117
118 if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
119 goto error;
120
121 if (!meter)
122 return 0;
123
124 if (nla_put(reply, OVS_METER_ATTR_STATS,
125 sizeof(struct ovs_flow_stats), &meter->stats) ||
126 nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
127 OVS_METER_ATTR_PAD))
128 goto error;
129
130 nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
131 if (!nla)
132 goto error;
133
134 band = meter->bands;
135
136 for (i = 0; i < meter->n_bands; ++i, ++band) {
137 struct nlattr *band_nla;
138
139 band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
140 if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS,
141 sizeof(struct ovs_flow_stats),
142 &band->stats))
143 goto error;
144 nla_nest_end(reply, band_nla);
145 }
146 nla_nest_end(reply, nla);
147
148 return 0;
149error:
150 return -EMSGSIZE;
151}
152
153static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
154{
155 struct sk_buff *reply;
156 struct ovs_header *ovs_reply_header;
157 struct nlattr *nla, *band_nla;
158 int err;
159
160 reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
161 &ovs_reply_header);
162 if (IS_ERR(reply))
163 return PTR_ERR(reply);
164
165 if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS, U32_MAX) ||
166 nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
167 goto nla_put_failure;
168
169 nla = nla_nest_start(reply, OVS_METER_ATTR_BANDS);
170 if (!nla)
171 goto nla_put_failure;
172
173 band_nla = nla_nest_start(reply, OVS_BAND_ATTR_UNSPEC);
174 if (!band_nla)
175 goto nla_put_failure;
176 /* Currently only DROP band type is supported. */
177 if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP))
178 goto nla_put_failure;
179 nla_nest_end(reply, band_nla);
180 nla_nest_end(reply, nla);
181
182 genlmsg_end(reply, ovs_reply_header);
183 return genlmsg_reply(reply, info);
184
185nla_put_failure:
186 nlmsg_free(reply);
187 err = -EMSGSIZE;
188 return err;
189}
190
191static struct dp_meter *dp_meter_create(struct nlattr **a)
192{
193 struct nlattr *nla;
194 int rem;
195 u16 n_bands = 0;
196 struct dp_meter *meter;
197 struct dp_meter_band *band;
198 int err;
199
200 /* Validate attributes, count the bands. */
201 if (!a[OVS_METER_ATTR_BANDS])
202 return ERR_PTR(-EINVAL);
203
204 nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem)
205 if (++n_bands > DP_MAX_BANDS)
206 return ERR_PTR(-EINVAL);
207
208 /* Allocate and set up the meter before locking anything. */
209 meter = kzalloc(n_bands * sizeof(struct dp_meter_band) +
210 sizeof(*meter), GFP_KERNEL);
211 if (!meter)
212 return ERR_PTR(-ENOMEM);
213
214 meter->used = div_u64(ktime_get_ns(), 1000 * 1000);
215 meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0;
216 meter->keep_stats = !a[OVS_METER_ATTR_CLEAR];
217 spin_lock_init(&meter->lock);
218 if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) {
219 meter->stats = *(struct ovs_flow_stats *)
220 nla_data(a[OVS_METER_ATTR_STATS]);
221 }
222 meter->n_bands = n_bands;
223
224 /* Set up meter bands. */
225 band = meter->bands;
226 nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) {
227 struct nlattr *attr[OVS_BAND_ATTR_MAX + 1];
228 u32 band_max_delta_t;
229
230 err = nla_parse((struct nlattr **)&attr, OVS_BAND_ATTR_MAX,
231 nla_data(nla), nla_len(nla), band_policy,
232 NULL);
233 if (err)
234 goto exit_free_meter;
235
236 if (!attr[OVS_BAND_ATTR_TYPE] ||
237 !attr[OVS_BAND_ATTR_RATE] ||
238 !attr[OVS_BAND_ATTR_BURST]) {
239 err = -EINVAL;
240 goto exit_free_meter;
241 }
242
243 band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
244 band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
245 if (band->rate == 0) {
246 err = -EINVAL;
247 goto exit_free_meter;
248 }
249
250 band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
251 /* Figure out max delta_t that is enough to fill any bucket.
252 * Keep max_delta_t size to the bucket units:
253 * pkts => 1/1000 packets, kilobits => bits.
254 *
255 * Start with a full bucket.
256 */
257 band->bucket = (band->burst_size + band->rate) * 1000;
258 band_max_delta_t = band->bucket / band->rate;
259 if (band_max_delta_t > meter->max_delta_t)
260 meter->max_delta_t = band_max_delta_t;
261 band++;
262 }
263
264 return meter;
265
266exit_free_meter:
267 kfree(meter);
268 return ERR_PTR(err);
269}
270
271static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info)
272{
273 struct nlattr **a = info->attrs;
274 struct dp_meter *meter, *old_meter;
275 struct sk_buff *reply;
276 struct ovs_header *ovs_reply_header;
277 struct ovs_header *ovs_header = info->userhdr;
278 struct datapath *dp;
279 int err;
280 u32 meter_id;
281 bool failed;
282
283 meter = dp_meter_create(a);
284 if (IS_ERR_OR_NULL(meter))
285 return PTR_ERR(meter);
286
287 reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET,
288 &ovs_reply_header);
289 if (IS_ERR(reply)) {
290 err = PTR_ERR(reply);
291 goto exit_free_meter;
292 }
293
294 ovs_lock();
295 dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
296 if (!dp) {
297 err = -ENODEV;
298 goto exit_unlock;
299 }
300
301 if (!a[OVS_METER_ATTR_ID]) {
302 err = -ENODEV;
303 goto exit_unlock;
304 }
305
306 meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
307
308 /* Cannot fail after this. */
309 old_meter = lookup_meter(dp, meter_id);
310 detach_meter(old_meter);
311 attach_meter(dp, meter);
312 ovs_unlock();
313
314 /* Build response with the meter_id and stats from
315 * the old meter, if any.
316 */
317 failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id);
318 WARN_ON(failed);
319 if (old_meter) {
320 spin_lock_bh(&old_meter->lock);
321 if (old_meter->keep_stats) {
322 err = ovs_meter_cmd_reply_stats(reply, meter_id,
323 old_meter);
324 WARN_ON(err);
325 }
326 spin_unlock_bh(&old_meter->lock);
327 ovs_meter_free(old_meter);
328 }
329
330 genlmsg_end(reply, ovs_reply_header);
331 return genlmsg_reply(reply, info);
332
333exit_unlock:
334 ovs_unlock();
335 nlmsg_free(reply);
336exit_free_meter:
337 kfree(meter);
338 return err;
339}
340
341static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
342{
343 struct nlattr **a = info->attrs;
344 u32 meter_id;
345 struct ovs_header *ovs_header = info->userhdr;
346 struct ovs_header *ovs_reply_header;
347 struct datapath *dp;
348 int err;
349 struct sk_buff *reply;
350 struct dp_meter *meter;
351
352 if (!a[OVS_METER_ATTR_ID])
353 return -EINVAL;
354
355 meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
356
357 reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET,
358 &ovs_reply_header);
359 if (IS_ERR(reply))
360 return PTR_ERR(reply);
361
362 ovs_lock();
363
364 dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
365 if (!dp) {
366 err = -ENODEV;
367 goto exit_unlock;
368 }
369
370 /* Locate meter, copy stats. */
371 meter = lookup_meter(dp, meter_id);
372 if (!meter) {
373 err = -ENOENT;
374 goto exit_unlock;
375 }
376
377 spin_lock_bh(&meter->lock);
378 err = ovs_meter_cmd_reply_stats(reply, meter_id, meter);
379 spin_unlock_bh(&meter->lock);
380 if (err)
381 goto exit_unlock;
382
383 ovs_unlock();
384
385 genlmsg_end(reply, ovs_reply_header);
386 return genlmsg_reply(reply, info);
387
388exit_unlock:
389 ovs_unlock();
390 nlmsg_free(reply);
391 return err;
392}
393
394static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
395{
396 struct nlattr **a = info->attrs;
397 u32 meter_id;
398 struct ovs_header *ovs_header = info->userhdr;
399 struct ovs_header *ovs_reply_header;
400 struct datapath *dp;
401 int err;
402 struct sk_buff *reply;
403 struct dp_meter *old_meter;
404
405 if (!a[OVS_METER_ATTR_ID])
406 return -EINVAL;
407 meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
408
409 reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
410 &ovs_reply_header);
411 if (IS_ERR(reply))
412 return PTR_ERR(reply);
413
414 ovs_lock();
415
416 dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
417 if (!dp) {
418 err = -ENODEV;
419 goto exit_unlock;
420 }
421
422 old_meter = lookup_meter(dp, meter_id);
423 if (old_meter) {
424 spin_lock_bh(&old_meter->lock);
425 err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
426 WARN_ON(err);
427 spin_unlock_bh(&old_meter->lock);
428 detach_meter(old_meter);
429 }
430 ovs_unlock();
431 ovs_meter_free(old_meter);
432 genlmsg_end(reply, ovs_reply_header);
433 return genlmsg_reply(reply, info);
434
435exit_unlock:
436 ovs_unlock();
437 nlmsg_free(reply);
438 return err;
439}
440
441/* Meter action execution.
442 *
443 * Return true 'meter_id' drop band is triggered. The 'skb' should be
444 * dropped by the caller'.
445 */
446bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
447 struct sw_flow_key *key, u32 meter_id)
448{
449 struct dp_meter *meter;
450 struct dp_meter_band *band;
451 long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
452 long long int long_delta_ms;
453 u32 delta_ms;
454 u32 cost;
455 int i, band_exceeded_max = -1;
456 u32 band_exceeded_rate = 0;
457
458 meter = lookup_meter(dp, meter_id);
459 /* Do not drop the packet when there is no meter. */
460 if (!meter)
461 return false;
462
463 /* Lock the meter while using it. */
464 spin_lock(&meter->lock);
465
466 long_delta_ms = (now_ms - meter->used); /* ms */
467
468 /* Make sure delta_ms will not be too large, so that bucket will not
469 * wrap around below.
470 */
471 delta_ms = (long_delta_ms > (long long int)meter->max_delta_t)
472 ? meter->max_delta_t : (u32)long_delta_ms;
473
474 /* Update meter statistics.
475 */
476 meter->used = now_ms;
477 meter->stats.n_packets += 1;
478 meter->stats.n_bytes += skb->len;
479
480 /* Bucket rate is either in kilobits per second, or in packets per
481 * second. We maintain the bucket in the units of either bits or
482 * 1/1000th of a packet, correspondingly.
483 * Then, when rate is multiplied with milliseconds, we get the
484 * bucket units:
485 * msec * kbps = bits, and
486 * msec * packets/sec = 1/1000 packets.
487 *
488 * 'cost' is the number of bucket units in this packet.
489 */
490 cost = (meter->kbps) ? skb->len * 8 : 1000;
491
492 /* Update all bands and find the one hit with the highest rate. */
493 for (i = 0; i < meter->n_bands; ++i) {
494 long long int max_bucket_size;
495
496 band = &meter->bands[i];
497 max_bucket_size = (band->burst_size + band->rate) * 1000LL;
498
499 band->bucket += delta_ms * band->rate;
500 if (band->bucket > max_bucket_size)
501 band->bucket = max_bucket_size;
502
503 if (band->bucket >= cost) {
504 band->bucket -= cost;
505 } else if (band->rate > band_exceeded_rate) {
506 band_exceeded_rate = band->rate;
507 band_exceeded_max = i;
508 }
509 }
510
511 if (band_exceeded_max >= 0) {
512 /* Update band statistics. */
513 band = &meter->bands[band_exceeded_max];
514 band->stats.n_packets += 1;
515 band->stats.n_bytes += skb->len;
516
517 /* Drop band triggered, let the caller drop the 'skb'. */
518 if (band->type == OVS_METER_BAND_TYPE_DROP) {
519 spin_unlock(&meter->lock);
520 return true;
521 }
522 }
523
524 spin_unlock(&meter->lock);
525 return false;
526}
527
528static struct genl_ops dp_meter_genl_ops[] = {
529 { .cmd = OVS_METER_CMD_FEATURES,
530 .flags = 0, /* OK for unprivileged users. */
531 .policy = meter_policy,
532 .doit = ovs_meter_cmd_features
533 },
534 { .cmd = OVS_METER_CMD_SET,
535 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
536 * privilege.
537 */
538 .policy = meter_policy,
539 .doit = ovs_meter_cmd_set,
540 },
541 { .cmd = OVS_METER_CMD_GET,
542 .flags = 0, /* OK for unprivileged users. */
543 .policy = meter_policy,
544 .doit = ovs_meter_cmd_get,
545 },
546 { .cmd = OVS_METER_CMD_DEL,
547 .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN
548 * privilege.
549 */
550 .policy = meter_policy,
551 .doit = ovs_meter_cmd_del
552 },
553};
554
555static const struct genl_multicast_group ovs_meter_multicast_group = {
556 .name = OVS_METER_MCGROUP,
557};
558
559struct genl_family dp_meter_genl_family __ro_after_init = {
560 .hdrsize = sizeof(struct ovs_header),
561 .name = OVS_METER_FAMILY,
562 .version = OVS_METER_VERSION,
563 .maxattr = OVS_METER_ATTR_MAX,
564 .netnsok = true,
565 .parallel_ops = true,
566 .ops = dp_meter_genl_ops,
567 .n_ops = ARRAY_SIZE(dp_meter_genl_ops),
568 .mcgrps = &ovs_meter_multicast_group,
569 .n_mcgrps = 1,
570 .module = THIS_MODULE,
571};
572
573int ovs_meters_init(struct datapath *dp)
574{
575 int i;
576
577 dp->meters = kmalloc_array(METER_HASH_BUCKETS,
578 sizeof(struct hlist_head), GFP_KERNEL);
579
580 if (!dp->meters)
581 return -ENOMEM;
582
583 for (i = 0; i < METER_HASH_BUCKETS; i++)
584 INIT_HLIST_HEAD(&dp->meters[i]);
585
586 return 0;
587}
588
589void ovs_meters_exit(struct datapath *dp)
590{
591 int i;
592
593 for (i = 0; i < METER_HASH_BUCKETS; i++) {
594 struct hlist_head *head = &dp->meters[i];
595 struct dp_meter *meter;
596 struct hlist_node *n;
597
598 hlist_for_each_entry_safe(meter, n, head, dp_hash_node)
599 kfree(meter);
600 }
601
602 kfree(dp->meters);
603}