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[thirdparty/linux.git] / net / core / drop_monitor.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Monitoring code for network dropped packet alerts
4 *
5 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/netdevice.h>
11 #include <linux/etherdevice.h>
12 #include <linux/string.h>
13 #include <linux/if_arp.h>
14 #include <linux/inetdevice.h>
15 #include <linux/inet.h>
16 #include <linux/interrupt.h>
17 #include <linux/netpoll.h>
18 #include <linux/sched.h>
19 #include <linux/delay.h>
20 #include <linux/types.h>
21 #include <linux/workqueue.h>
22 #include <linux/netlink.h>
23 #include <linux/net_dropmon.h>
24 #include <linux/percpu.h>
25 #include <linux/timer.h>
26 #include <linux/bitops.h>
27 #include <linux/slab.h>
28 #include <linux/module.h>
29 #include <net/drop_monitor.h>
30 #include <net/genetlink.h>
31 #include <net/netevent.h>
32 #include <net/flow_offload.h>
33
34 #include <trace/events/skb.h>
35 #include <trace/events/napi.h>
36
37 #include <asm/unaligned.h>
38
39 #define TRACE_ON 1
40 #define TRACE_OFF 0
41
42 /*
43 * Globals, our netlink socket pointer
44 * and the work handle that will send up
45 * netlink alerts
46 */
47 static int trace_state = TRACE_OFF;
48 static bool monitor_hw;
49
50 /* net_dm_mutex
51 *
52 * An overall lock guarding every operation coming from userspace.
53 * It also guards the global 'hw_stats_list' list.
54 */
55 static DEFINE_MUTEX(net_dm_mutex);
56
57 struct net_dm_stats {
58 u64 dropped;
59 struct u64_stats_sync syncp;
60 };
61
62 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
63
64 struct net_dm_hw_entry {
65 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
66 u32 count;
67 };
68
69 struct net_dm_hw_entries {
70 u32 num_entries;
71 struct net_dm_hw_entry entries[];
72 };
73
74 struct per_cpu_dm_data {
75 spinlock_t lock; /* Protects 'skb', 'hw_entries' and
76 * 'send_timer'
77 */
78 union {
79 struct sk_buff *skb;
80 struct net_dm_hw_entries *hw_entries;
81 };
82 struct sk_buff_head drop_queue;
83 struct work_struct dm_alert_work;
84 struct timer_list send_timer;
85 struct net_dm_stats stats;
86 };
87
88 struct dm_hw_stat_delta {
89 struct net_device *dev;
90 unsigned long last_rx;
91 struct list_head list;
92 struct rcu_head rcu;
93 unsigned long last_drop_val;
94 };
95
96 static struct genl_family net_drop_monitor_family;
97
98 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
100
101 static int dm_hit_limit = 64;
102 static int dm_delay = 1;
103 static unsigned long dm_hw_check_delta = 2*HZ;
104 static LIST_HEAD(hw_stats_list);
105
106 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
107 static u32 net_dm_trunc_len;
108 static u32 net_dm_queue_len = 1000;
109
110 struct net_dm_alert_ops {
111 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
112 void *location);
113 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
114 int work, int budget);
115 void (*work_item_func)(struct work_struct *work);
116 void (*hw_work_item_func)(struct work_struct *work);
117 void (*hw_probe)(struct sk_buff *skb,
118 const struct net_dm_hw_metadata *hw_metadata);
119 };
120
121 struct net_dm_skb_cb {
122 union {
123 struct net_dm_hw_metadata *hw_metadata;
124 void *pc;
125 };
126 };
127
128 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
129
130 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
131 {
132 size_t al;
133 struct net_dm_alert_msg *msg;
134 struct nlattr *nla;
135 struct sk_buff *skb;
136 unsigned long flags;
137 void *msg_header;
138
139 al = sizeof(struct net_dm_alert_msg);
140 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
141 al += sizeof(struct nlattr);
142
143 skb = genlmsg_new(al, GFP_KERNEL);
144
145 if (!skb)
146 goto err;
147
148 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
149 0, NET_DM_CMD_ALERT);
150 if (!msg_header) {
151 nlmsg_free(skb);
152 skb = NULL;
153 goto err;
154 }
155 nla = nla_reserve(skb, NLA_UNSPEC,
156 sizeof(struct net_dm_alert_msg));
157 if (!nla) {
158 nlmsg_free(skb);
159 skb = NULL;
160 goto err;
161 }
162 msg = nla_data(nla);
163 memset(msg, 0, al);
164 goto out;
165
166 err:
167 mod_timer(&data->send_timer, jiffies + HZ / 10);
168 out:
169 spin_lock_irqsave(&data->lock, flags);
170 swap(data->skb, skb);
171 spin_unlock_irqrestore(&data->lock, flags);
172
173 if (skb) {
174 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
175 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
176
177 genlmsg_end(skb, genlmsg_data(gnlh));
178 }
179
180 return skb;
181 }
182
183 static const struct genl_multicast_group dropmon_mcgrps[] = {
184 { .name = "events", },
185 };
186
187 static void send_dm_alert(struct work_struct *work)
188 {
189 struct sk_buff *skb;
190 struct per_cpu_dm_data *data;
191
192 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
193
194 skb = reset_per_cpu_data(data);
195
196 if (skb)
197 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
198 0, GFP_KERNEL);
199 }
200
201 /*
202 * This is the timer function to delay the sending of an alert
203 * in the event that more drops will arrive during the
204 * hysteresis period.
205 */
206 static void sched_send_work(struct timer_list *t)
207 {
208 struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
209
210 schedule_work(&data->dm_alert_work);
211 }
212
213 static void trace_drop_common(struct sk_buff *skb, void *location)
214 {
215 struct net_dm_alert_msg *msg;
216 struct nlmsghdr *nlh;
217 struct nlattr *nla;
218 int i;
219 struct sk_buff *dskb;
220 struct per_cpu_dm_data *data;
221 unsigned long flags;
222
223 local_irq_save(flags);
224 data = this_cpu_ptr(&dm_cpu_data);
225 spin_lock(&data->lock);
226 dskb = data->skb;
227
228 if (!dskb)
229 goto out;
230
231 nlh = (struct nlmsghdr *)dskb->data;
232 nla = genlmsg_data(nlmsg_data(nlh));
233 msg = nla_data(nla);
234 for (i = 0; i < msg->entries; i++) {
235 if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
236 msg->points[i].count++;
237 goto out;
238 }
239 }
240 if (msg->entries == dm_hit_limit)
241 goto out;
242 /*
243 * We need to create a new entry
244 */
245 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
246 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
247 memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
248 msg->points[msg->entries].count = 1;
249 msg->entries++;
250
251 if (!timer_pending(&data->send_timer)) {
252 data->send_timer.expires = jiffies + dm_delay * HZ;
253 add_timer(&data->send_timer);
254 }
255
256 out:
257 spin_unlock_irqrestore(&data->lock, flags);
258 }
259
260 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
261 {
262 trace_drop_common(skb, location);
263 }
264
265 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
266 int work, int budget)
267 {
268 struct dm_hw_stat_delta *new_stat;
269
270 /*
271 * Don't check napi structures with no associated device
272 */
273 if (!napi->dev)
274 return;
275
276 rcu_read_lock();
277 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
278 /*
279 * only add a note to our monitor buffer if:
280 * 1) this is the dev we received on
281 * 2) its after the last_rx delta
282 * 3) our rx_dropped count has gone up
283 */
284 if ((new_stat->dev == napi->dev) &&
285 (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
286 (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
287 trace_drop_common(NULL, NULL);
288 new_stat->last_drop_val = napi->dev->stats.rx_dropped;
289 new_stat->last_rx = jiffies;
290 break;
291 }
292 }
293 rcu_read_unlock();
294 }
295
296 static struct net_dm_hw_entries *
297 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
298 {
299 struct net_dm_hw_entries *hw_entries;
300 unsigned long flags;
301
302 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
303 GFP_KERNEL);
304 if (!hw_entries) {
305 /* If the memory allocation failed, we try to perform another
306 * allocation in 1/10 second. Otherwise, the probe function
307 * will constantly bail out.
308 */
309 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
310 }
311
312 spin_lock_irqsave(&hw_data->lock, flags);
313 swap(hw_data->hw_entries, hw_entries);
314 spin_unlock_irqrestore(&hw_data->lock, flags);
315
316 return hw_entries;
317 }
318
319 static int net_dm_hw_entry_put(struct sk_buff *msg,
320 const struct net_dm_hw_entry *hw_entry)
321 {
322 struct nlattr *attr;
323
324 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
325 if (!attr)
326 return -EMSGSIZE;
327
328 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
329 goto nla_put_failure;
330
331 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
332 goto nla_put_failure;
333
334 nla_nest_end(msg, attr);
335
336 return 0;
337
338 nla_put_failure:
339 nla_nest_cancel(msg, attr);
340 return -EMSGSIZE;
341 }
342
343 static int net_dm_hw_entries_put(struct sk_buff *msg,
344 const struct net_dm_hw_entries *hw_entries)
345 {
346 struct nlattr *attr;
347 int i;
348
349 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
350 if (!attr)
351 return -EMSGSIZE;
352
353 for (i = 0; i < hw_entries->num_entries; i++) {
354 int rc;
355
356 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
357 if (rc)
358 goto nla_put_failure;
359 }
360
361 nla_nest_end(msg, attr);
362
363 return 0;
364
365 nla_put_failure:
366 nla_nest_cancel(msg, attr);
367 return -EMSGSIZE;
368 }
369
370 static int
371 net_dm_hw_summary_report_fill(struct sk_buff *msg,
372 const struct net_dm_hw_entries *hw_entries)
373 {
374 struct net_dm_alert_msg anc_hdr = { 0 };
375 void *hdr;
376 int rc;
377
378 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
379 NET_DM_CMD_ALERT);
380 if (!hdr)
381 return -EMSGSIZE;
382
383 /* We need to put the ancillary header in order not to break user
384 * space.
385 */
386 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
387 goto nla_put_failure;
388
389 rc = net_dm_hw_entries_put(msg, hw_entries);
390 if (rc)
391 goto nla_put_failure;
392
393 genlmsg_end(msg, hdr);
394
395 return 0;
396
397 nla_put_failure:
398 genlmsg_cancel(msg, hdr);
399 return -EMSGSIZE;
400 }
401
402 static void net_dm_hw_summary_work(struct work_struct *work)
403 {
404 struct net_dm_hw_entries *hw_entries;
405 struct per_cpu_dm_data *hw_data;
406 struct sk_buff *msg;
407 int rc;
408
409 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
410
411 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
412 if (!hw_entries)
413 return;
414
415 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
416 if (!msg)
417 goto out;
418
419 rc = net_dm_hw_summary_report_fill(msg, hw_entries);
420 if (rc) {
421 nlmsg_free(msg);
422 goto out;
423 }
424
425 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
426
427 out:
428 kfree(hw_entries);
429 }
430
431 static void
432 net_dm_hw_summary_probe(struct sk_buff *skb,
433 const struct net_dm_hw_metadata *hw_metadata)
434 {
435 struct net_dm_hw_entries *hw_entries;
436 struct net_dm_hw_entry *hw_entry;
437 struct per_cpu_dm_data *hw_data;
438 unsigned long flags;
439 int i;
440
441 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
442 spin_lock_irqsave(&hw_data->lock, flags);
443 hw_entries = hw_data->hw_entries;
444
445 if (!hw_entries)
446 goto out;
447
448 for (i = 0; i < hw_entries->num_entries; i++) {
449 hw_entry = &hw_entries->entries[i];
450 if (!strncmp(hw_entry->trap_name, hw_metadata->trap_name,
451 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
452 hw_entry->count++;
453 goto out;
454 }
455 }
456 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
457 goto out;
458
459 hw_entry = &hw_entries->entries[hw_entries->num_entries];
460 strlcpy(hw_entry->trap_name, hw_metadata->trap_name,
461 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
462 hw_entry->count = 1;
463 hw_entries->num_entries++;
464
465 if (!timer_pending(&hw_data->send_timer)) {
466 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
467 add_timer(&hw_data->send_timer);
468 }
469
470 out:
471 spin_unlock_irqrestore(&hw_data->lock, flags);
472 }
473
474 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
475 .kfree_skb_probe = trace_kfree_skb_hit,
476 .napi_poll_probe = trace_napi_poll_hit,
477 .work_item_func = send_dm_alert,
478 .hw_work_item_func = net_dm_hw_summary_work,
479 .hw_probe = net_dm_hw_summary_probe,
480 };
481
482 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
483 struct sk_buff *skb,
484 void *location)
485 {
486 ktime_t tstamp = ktime_get_real();
487 struct per_cpu_dm_data *data;
488 struct sk_buff *nskb;
489 unsigned long flags;
490
491 if (!skb_mac_header_was_set(skb))
492 return;
493
494 nskb = skb_clone(skb, GFP_ATOMIC);
495 if (!nskb)
496 return;
497
498 NET_DM_SKB_CB(nskb)->pc = location;
499 /* Override the timestamp because we care about the time when the
500 * packet was dropped.
501 */
502 nskb->tstamp = tstamp;
503
504 data = this_cpu_ptr(&dm_cpu_data);
505
506 spin_lock_irqsave(&data->drop_queue.lock, flags);
507 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
508 __skb_queue_tail(&data->drop_queue, nskb);
509 else
510 goto unlock_free;
511 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
512
513 schedule_work(&data->dm_alert_work);
514
515 return;
516
517 unlock_free:
518 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
519 u64_stats_update_begin(&data->stats.syncp);
520 data->stats.dropped++;
521 u64_stats_update_end(&data->stats.syncp);
522 consume_skb(nskb);
523 }
524
525 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
526 struct napi_struct *napi,
527 int work, int budget)
528 {
529 }
530
531 static size_t net_dm_in_port_size(void)
532 {
533 /* NET_DM_ATTR_IN_PORT nest */
534 return nla_total_size(0) +
535 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
536 nla_total_size(sizeof(u32)) +
537 /* NET_DM_ATTR_PORT_NETDEV_NAME */
538 nla_total_size(IFNAMSIZ + 1);
539 }
540
541 #define NET_DM_MAX_SYMBOL_LEN 40
542
543 static size_t net_dm_packet_report_size(size_t payload_len)
544 {
545 size_t size;
546
547 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
548
549 return NLMSG_ALIGN(size) +
550 /* NET_DM_ATTR_ORIGIN */
551 nla_total_size(sizeof(u16)) +
552 /* NET_DM_ATTR_PC */
553 nla_total_size(sizeof(u64)) +
554 /* NET_DM_ATTR_SYMBOL */
555 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
556 /* NET_DM_ATTR_IN_PORT */
557 net_dm_in_port_size() +
558 /* NET_DM_ATTR_TIMESTAMP */
559 nla_total_size(sizeof(u64)) +
560 /* NET_DM_ATTR_ORIG_LEN */
561 nla_total_size(sizeof(u32)) +
562 /* NET_DM_ATTR_PROTO */
563 nla_total_size(sizeof(u16)) +
564 /* NET_DM_ATTR_PAYLOAD */
565 nla_total_size(payload_len);
566 }
567
568 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
569 const char *name)
570 {
571 struct nlattr *attr;
572
573 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
574 if (!attr)
575 return -EMSGSIZE;
576
577 if (ifindex &&
578 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
579 goto nla_put_failure;
580
581 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
582 goto nla_put_failure;
583
584 nla_nest_end(msg, attr);
585
586 return 0;
587
588 nla_put_failure:
589 nla_nest_cancel(msg, attr);
590 return -EMSGSIZE;
591 }
592
593 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
594 size_t payload_len)
595 {
596 u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
597 char buf[NET_DM_MAX_SYMBOL_LEN];
598 struct nlattr *attr;
599 void *hdr;
600 int rc;
601
602 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
603 NET_DM_CMD_PACKET_ALERT);
604 if (!hdr)
605 return -EMSGSIZE;
606
607 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
608 goto nla_put_failure;
609
610 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
611 goto nla_put_failure;
612
613 snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
614 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
615 goto nla_put_failure;
616
617 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
618 if (rc)
619 goto nla_put_failure;
620
621 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
622 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
623 goto nla_put_failure;
624
625 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
626 goto nla_put_failure;
627
628 if (!payload_len)
629 goto out;
630
631 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
632 goto nla_put_failure;
633
634 attr = skb_put(msg, nla_total_size(payload_len));
635 attr->nla_type = NET_DM_ATTR_PAYLOAD;
636 attr->nla_len = nla_attr_size(payload_len);
637 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
638 goto nla_put_failure;
639
640 out:
641 genlmsg_end(msg, hdr);
642
643 return 0;
644
645 nla_put_failure:
646 genlmsg_cancel(msg, hdr);
647 return -EMSGSIZE;
648 }
649
650 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
651
652 static void net_dm_packet_report(struct sk_buff *skb)
653 {
654 struct sk_buff *msg;
655 size_t payload_len;
656 int rc;
657
658 /* Make sure we start copying the packet from the MAC header */
659 if (skb->data > skb_mac_header(skb))
660 skb_push(skb, skb->data - skb_mac_header(skb));
661 else
662 skb_pull(skb, skb_mac_header(skb) - skb->data);
663
664 /* Ensure packet fits inside a single netlink attribute */
665 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
666 if (net_dm_trunc_len)
667 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
668
669 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
670 if (!msg)
671 goto out;
672
673 rc = net_dm_packet_report_fill(msg, skb, payload_len);
674 if (rc) {
675 nlmsg_free(msg);
676 goto out;
677 }
678
679 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
680
681 out:
682 consume_skb(skb);
683 }
684
685 static void net_dm_packet_work(struct work_struct *work)
686 {
687 struct per_cpu_dm_data *data;
688 struct sk_buff_head list;
689 struct sk_buff *skb;
690 unsigned long flags;
691
692 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
693
694 __skb_queue_head_init(&list);
695
696 spin_lock_irqsave(&data->drop_queue.lock, flags);
697 skb_queue_splice_tail_init(&data->drop_queue, &list);
698 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
699
700 while ((skb = __skb_dequeue(&list)))
701 net_dm_packet_report(skb);
702 }
703
704 static size_t
705 net_dm_flow_action_cookie_size(const struct net_dm_hw_metadata *hw_metadata)
706 {
707 return hw_metadata->fa_cookie ?
708 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
709 }
710
711 static size_t
712 net_dm_hw_packet_report_size(size_t payload_len,
713 const struct net_dm_hw_metadata *hw_metadata)
714 {
715 size_t size;
716
717 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
718
719 return NLMSG_ALIGN(size) +
720 /* NET_DM_ATTR_ORIGIN */
721 nla_total_size(sizeof(u16)) +
722 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
723 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
724 /* NET_DM_ATTR_HW_TRAP_NAME */
725 nla_total_size(strlen(hw_metadata->trap_name) + 1) +
726 /* NET_DM_ATTR_IN_PORT */
727 net_dm_in_port_size() +
728 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
729 net_dm_flow_action_cookie_size(hw_metadata) +
730 /* NET_DM_ATTR_TIMESTAMP */
731 nla_total_size(sizeof(u64)) +
732 /* NET_DM_ATTR_ORIG_LEN */
733 nla_total_size(sizeof(u32)) +
734 /* NET_DM_ATTR_PROTO */
735 nla_total_size(sizeof(u16)) +
736 /* NET_DM_ATTR_PAYLOAD */
737 nla_total_size(payload_len);
738 }
739
740 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
741 struct sk_buff *skb, size_t payload_len)
742 {
743 struct net_dm_hw_metadata *hw_metadata;
744 struct nlattr *attr;
745 void *hdr;
746
747 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
748
749 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
750 NET_DM_CMD_PACKET_ALERT);
751 if (!hdr)
752 return -EMSGSIZE;
753
754 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
755 goto nla_put_failure;
756
757 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
758 hw_metadata->trap_group_name))
759 goto nla_put_failure;
760
761 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
762 hw_metadata->trap_name))
763 goto nla_put_failure;
764
765 if (hw_metadata->input_dev) {
766 struct net_device *dev = hw_metadata->input_dev;
767 int rc;
768
769 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
770 dev->name);
771 if (rc)
772 goto nla_put_failure;
773 }
774
775 if (hw_metadata->fa_cookie &&
776 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
777 hw_metadata->fa_cookie->cookie_len,
778 hw_metadata->fa_cookie->cookie))
779 goto nla_put_failure;
780
781 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
782 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
783 goto nla_put_failure;
784
785 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
786 goto nla_put_failure;
787
788 if (!payload_len)
789 goto out;
790
791 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
792 goto nla_put_failure;
793
794 attr = skb_put(msg, nla_total_size(payload_len));
795 attr->nla_type = NET_DM_ATTR_PAYLOAD;
796 attr->nla_len = nla_attr_size(payload_len);
797 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
798 goto nla_put_failure;
799
800 out:
801 genlmsg_end(msg, hdr);
802
803 return 0;
804
805 nla_put_failure:
806 genlmsg_cancel(msg, hdr);
807 return -EMSGSIZE;
808 }
809
810 static struct net_dm_hw_metadata *
811 net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata)
812 {
813 const struct flow_action_cookie *fa_cookie;
814 struct net_dm_hw_metadata *n_hw_metadata;
815 const char *trap_group_name;
816 const char *trap_name;
817
818 n_hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
819 if (!n_hw_metadata)
820 return NULL;
821
822 trap_group_name = kstrdup(hw_metadata->trap_group_name, GFP_ATOMIC);
823 if (!trap_group_name)
824 goto free_hw_metadata;
825 n_hw_metadata->trap_group_name = trap_group_name;
826
827 trap_name = kstrdup(hw_metadata->trap_name, GFP_ATOMIC);
828 if (!trap_name)
829 goto free_trap_group;
830 n_hw_metadata->trap_name = trap_name;
831
832 if (hw_metadata->fa_cookie) {
833 size_t cookie_size = sizeof(*fa_cookie) +
834 hw_metadata->fa_cookie->cookie_len;
835
836 fa_cookie = kmemdup(hw_metadata->fa_cookie, cookie_size,
837 GFP_ATOMIC);
838 if (!fa_cookie)
839 goto free_trap_name;
840 n_hw_metadata->fa_cookie = fa_cookie;
841 }
842
843 n_hw_metadata->input_dev = hw_metadata->input_dev;
844 if (n_hw_metadata->input_dev)
845 dev_hold(n_hw_metadata->input_dev);
846
847 return n_hw_metadata;
848
849 free_trap_name:
850 kfree(trap_name);
851 free_trap_group:
852 kfree(trap_group_name);
853 free_hw_metadata:
854 kfree(n_hw_metadata);
855 return NULL;
856 }
857
858 static void
859 net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata)
860 {
861 if (hw_metadata->input_dev)
862 dev_put(hw_metadata->input_dev);
863 kfree(hw_metadata->fa_cookie);
864 kfree(hw_metadata->trap_name);
865 kfree(hw_metadata->trap_group_name);
866 kfree(hw_metadata);
867 }
868
869 static void net_dm_hw_packet_report(struct sk_buff *skb)
870 {
871 struct net_dm_hw_metadata *hw_metadata;
872 struct sk_buff *msg;
873 size_t payload_len;
874 int rc;
875
876 if (skb->data > skb_mac_header(skb))
877 skb_push(skb, skb->data - skb_mac_header(skb));
878 else
879 skb_pull(skb, skb_mac_header(skb) - skb->data);
880
881 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
882 if (net_dm_trunc_len)
883 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
884
885 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
886 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
887 GFP_KERNEL);
888 if (!msg)
889 goto out;
890
891 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
892 if (rc) {
893 nlmsg_free(msg);
894 goto out;
895 }
896
897 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
898
899 out:
900 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
901 consume_skb(skb);
902 }
903
904 static void net_dm_hw_packet_work(struct work_struct *work)
905 {
906 struct per_cpu_dm_data *hw_data;
907 struct sk_buff_head list;
908 struct sk_buff *skb;
909 unsigned long flags;
910
911 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
912
913 __skb_queue_head_init(&list);
914
915 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
916 skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
917 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
918
919 while ((skb = __skb_dequeue(&list)))
920 net_dm_hw_packet_report(skb);
921 }
922
923 static void
924 net_dm_hw_packet_probe(struct sk_buff *skb,
925 const struct net_dm_hw_metadata *hw_metadata)
926 {
927 struct net_dm_hw_metadata *n_hw_metadata;
928 ktime_t tstamp = ktime_get_real();
929 struct per_cpu_dm_data *hw_data;
930 struct sk_buff *nskb;
931 unsigned long flags;
932
933 if (!skb_mac_header_was_set(skb))
934 return;
935
936 nskb = skb_clone(skb, GFP_ATOMIC);
937 if (!nskb)
938 return;
939
940 n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata);
941 if (!n_hw_metadata)
942 goto free;
943
944 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
945 nskb->tstamp = tstamp;
946
947 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
948
949 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
950 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
951 __skb_queue_tail(&hw_data->drop_queue, nskb);
952 else
953 goto unlock_free;
954 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
955
956 schedule_work(&hw_data->dm_alert_work);
957
958 return;
959
960 unlock_free:
961 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
962 u64_stats_update_begin(&hw_data->stats.syncp);
963 hw_data->stats.dropped++;
964 u64_stats_update_end(&hw_data->stats.syncp);
965 net_dm_hw_metadata_free(n_hw_metadata);
966 free:
967 consume_skb(nskb);
968 }
969
970 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
971 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
972 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
973 .work_item_func = net_dm_packet_work,
974 .hw_work_item_func = net_dm_hw_packet_work,
975 .hw_probe = net_dm_hw_packet_probe,
976 };
977
978 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
979 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
980 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
981 };
982
983 void net_dm_hw_report(struct sk_buff *skb,
984 const struct net_dm_hw_metadata *hw_metadata)
985 {
986 rcu_read_lock();
987
988 if (!monitor_hw)
989 goto out;
990
991 net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata);
992
993 out:
994 rcu_read_unlock();
995 }
996 EXPORT_SYMBOL_GPL(net_dm_hw_report);
997
998 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
999 {
1000 const struct net_dm_alert_ops *ops;
1001 int cpu;
1002
1003 if (monitor_hw) {
1004 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1005 return -EAGAIN;
1006 }
1007
1008 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1009
1010 if (!try_module_get(THIS_MODULE)) {
1011 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1012 return -ENODEV;
1013 }
1014
1015 for_each_possible_cpu(cpu) {
1016 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1017 struct net_dm_hw_entries *hw_entries;
1018
1019 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1020 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1021 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1022 kfree(hw_entries);
1023 }
1024
1025 monitor_hw = true;
1026
1027 return 0;
1028 }
1029
1030 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1031 {
1032 int cpu;
1033
1034 if (!monitor_hw) {
1035 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1036 return;
1037 }
1038
1039 monitor_hw = false;
1040
1041 /* After this call returns we are guaranteed that no CPU is processing
1042 * any hardware drops.
1043 */
1044 synchronize_rcu();
1045
1046 for_each_possible_cpu(cpu) {
1047 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1048 struct sk_buff *skb;
1049
1050 del_timer_sync(&hw_data->send_timer);
1051 cancel_work_sync(&hw_data->dm_alert_work);
1052 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1053 struct net_dm_hw_metadata *hw_metadata;
1054
1055 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1056 net_dm_hw_metadata_free(hw_metadata);
1057 consume_skb(skb);
1058 }
1059 }
1060
1061 module_put(THIS_MODULE);
1062 }
1063
1064 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1065 {
1066 const struct net_dm_alert_ops *ops;
1067 int cpu, rc;
1068
1069 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1070
1071 if (!try_module_get(THIS_MODULE)) {
1072 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1073 return -ENODEV;
1074 }
1075
1076 for_each_possible_cpu(cpu) {
1077 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1078 struct sk_buff *skb;
1079
1080 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1081 timer_setup(&data->send_timer, sched_send_work, 0);
1082 /* Allocate a new per-CPU skb for the summary alert message and
1083 * free the old one which might contain stale data from
1084 * previous tracing.
1085 */
1086 skb = reset_per_cpu_data(data);
1087 consume_skb(skb);
1088 }
1089
1090 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1091 if (rc) {
1092 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1093 goto err_module_put;
1094 }
1095
1096 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1097 if (rc) {
1098 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1099 goto err_unregister_trace;
1100 }
1101
1102 return 0;
1103
1104 err_unregister_trace:
1105 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1106 err_module_put:
1107 module_put(THIS_MODULE);
1108 return rc;
1109 }
1110
1111 static void net_dm_trace_off_set(void)
1112 {
1113 struct dm_hw_stat_delta *new_stat, *temp;
1114 const struct net_dm_alert_ops *ops;
1115 int cpu;
1116
1117 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1118
1119 unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1120 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1121
1122 tracepoint_synchronize_unregister();
1123
1124 /* Make sure we do not send notifications to user space after request
1125 * to stop tracing returns.
1126 */
1127 for_each_possible_cpu(cpu) {
1128 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1129 struct sk_buff *skb;
1130
1131 del_timer_sync(&data->send_timer);
1132 cancel_work_sync(&data->dm_alert_work);
1133 while ((skb = __skb_dequeue(&data->drop_queue)))
1134 consume_skb(skb);
1135 }
1136
1137 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
1138 if (new_stat->dev == NULL) {
1139 list_del_rcu(&new_stat->list);
1140 kfree_rcu(new_stat, rcu);
1141 }
1142 }
1143
1144 module_put(THIS_MODULE);
1145 }
1146
1147 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1148 {
1149 int rc = 0;
1150
1151 if (state == trace_state) {
1152 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1153 return -EAGAIN;
1154 }
1155
1156 switch (state) {
1157 case TRACE_ON:
1158 rc = net_dm_trace_on_set(extack);
1159 break;
1160 case TRACE_OFF:
1161 net_dm_trace_off_set();
1162 break;
1163 default:
1164 rc = 1;
1165 break;
1166 }
1167
1168 if (!rc)
1169 trace_state = state;
1170 else
1171 rc = -EINPROGRESS;
1172
1173 return rc;
1174 }
1175
1176 static bool net_dm_is_monitoring(void)
1177 {
1178 return trace_state == TRACE_ON || monitor_hw;
1179 }
1180
1181 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1182 enum net_dm_alert_mode *p_alert_mode)
1183 {
1184 u8 val;
1185
1186 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1187
1188 switch (val) {
1189 case NET_DM_ALERT_MODE_SUMMARY: /* fall-through */
1190 case NET_DM_ALERT_MODE_PACKET:
1191 *p_alert_mode = val;
1192 break;
1193 default:
1194 return -EINVAL;
1195 }
1196
1197 return 0;
1198 }
1199
1200 static int net_dm_alert_mode_set(struct genl_info *info)
1201 {
1202 struct netlink_ext_ack *extack = info->extack;
1203 enum net_dm_alert_mode alert_mode;
1204 int rc;
1205
1206 if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1207 return 0;
1208
1209 rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1210 if (rc) {
1211 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1212 return -EINVAL;
1213 }
1214
1215 net_dm_alert_mode = alert_mode;
1216
1217 return 0;
1218 }
1219
1220 static void net_dm_trunc_len_set(struct genl_info *info)
1221 {
1222 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1223 return;
1224
1225 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1226 }
1227
1228 static void net_dm_queue_len_set(struct genl_info *info)
1229 {
1230 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1231 return;
1232
1233 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1234 }
1235
1236 static int net_dm_cmd_config(struct sk_buff *skb,
1237 struct genl_info *info)
1238 {
1239 struct netlink_ext_ack *extack = info->extack;
1240 int rc;
1241
1242 if (net_dm_is_monitoring()) {
1243 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1244 return -EBUSY;
1245 }
1246
1247 rc = net_dm_alert_mode_set(info);
1248 if (rc)
1249 return rc;
1250
1251 net_dm_trunc_len_set(info);
1252
1253 net_dm_queue_len_set(info);
1254
1255 return 0;
1256 }
1257
1258 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1259 struct netlink_ext_ack *extack)
1260 {
1261 bool sw_set = false;
1262 int rc;
1263
1264 if (set_sw) {
1265 rc = set_all_monitor_traces(TRACE_ON, extack);
1266 if (rc)
1267 return rc;
1268 sw_set = true;
1269 }
1270
1271 if (set_hw) {
1272 rc = net_dm_hw_monitor_start(extack);
1273 if (rc)
1274 goto err_monitor_hw;
1275 }
1276
1277 return 0;
1278
1279 err_monitor_hw:
1280 if (sw_set)
1281 set_all_monitor_traces(TRACE_OFF, extack);
1282 return rc;
1283 }
1284
1285 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1286 struct netlink_ext_ack *extack)
1287 {
1288 if (set_hw)
1289 net_dm_hw_monitor_stop(extack);
1290 if (set_sw)
1291 set_all_monitor_traces(TRACE_OFF, extack);
1292 }
1293
1294 static int net_dm_cmd_trace(struct sk_buff *skb,
1295 struct genl_info *info)
1296 {
1297 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1298 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1299 struct netlink_ext_ack *extack = info->extack;
1300
1301 /* To maintain backward compatibility, we start / stop monitoring of
1302 * software drops if no flag is specified.
1303 */
1304 if (!set_sw && !set_hw)
1305 set_sw = true;
1306
1307 switch (info->genlhdr->cmd) {
1308 case NET_DM_CMD_START:
1309 return net_dm_monitor_start(set_sw, set_hw, extack);
1310 case NET_DM_CMD_STOP:
1311 net_dm_monitor_stop(set_sw, set_hw, extack);
1312 return 0;
1313 }
1314
1315 return -EOPNOTSUPP;
1316 }
1317
1318 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1319 {
1320 void *hdr;
1321
1322 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1323 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1324 if (!hdr)
1325 return -EMSGSIZE;
1326
1327 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1328 goto nla_put_failure;
1329
1330 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1331 goto nla_put_failure;
1332
1333 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1334 goto nla_put_failure;
1335
1336 genlmsg_end(msg, hdr);
1337
1338 return 0;
1339
1340 nla_put_failure:
1341 genlmsg_cancel(msg, hdr);
1342 return -EMSGSIZE;
1343 }
1344
1345 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1346 {
1347 struct sk_buff *msg;
1348 int rc;
1349
1350 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1351 if (!msg)
1352 return -ENOMEM;
1353
1354 rc = net_dm_config_fill(msg, info);
1355 if (rc)
1356 goto free_msg;
1357
1358 return genlmsg_reply(msg, info);
1359
1360 free_msg:
1361 nlmsg_free(msg);
1362 return rc;
1363 }
1364
1365 static void net_dm_stats_read(struct net_dm_stats *stats)
1366 {
1367 int cpu;
1368
1369 memset(stats, 0, sizeof(*stats));
1370 for_each_possible_cpu(cpu) {
1371 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1372 struct net_dm_stats *cpu_stats = &data->stats;
1373 unsigned int start;
1374 u64 dropped;
1375
1376 do {
1377 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1378 dropped = cpu_stats->dropped;
1379 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1380
1381 stats->dropped += dropped;
1382 }
1383 }
1384
1385 static int net_dm_stats_put(struct sk_buff *msg)
1386 {
1387 struct net_dm_stats stats;
1388 struct nlattr *attr;
1389
1390 net_dm_stats_read(&stats);
1391
1392 attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1393 if (!attr)
1394 return -EMSGSIZE;
1395
1396 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1397 stats.dropped, NET_DM_ATTR_PAD))
1398 goto nla_put_failure;
1399
1400 nla_nest_end(msg, attr);
1401
1402 return 0;
1403
1404 nla_put_failure:
1405 nla_nest_cancel(msg, attr);
1406 return -EMSGSIZE;
1407 }
1408
1409 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1410 {
1411 int cpu;
1412
1413 memset(stats, 0, sizeof(*stats));
1414 for_each_possible_cpu(cpu) {
1415 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1416 struct net_dm_stats *cpu_stats = &hw_data->stats;
1417 unsigned int start;
1418 u64 dropped;
1419
1420 do {
1421 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1422 dropped = cpu_stats->dropped;
1423 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1424
1425 stats->dropped += dropped;
1426 }
1427 }
1428
1429 static int net_dm_hw_stats_put(struct sk_buff *msg)
1430 {
1431 struct net_dm_stats stats;
1432 struct nlattr *attr;
1433
1434 net_dm_hw_stats_read(&stats);
1435
1436 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1437 if (!attr)
1438 return -EMSGSIZE;
1439
1440 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1441 stats.dropped, NET_DM_ATTR_PAD))
1442 goto nla_put_failure;
1443
1444 nla_nest_end(msg, attr);
1445
1446 return 0;
1447
1448 nla_put_failure:
1449 nla_nest_cancel(msg, attr);
1450 return -EMSGSIZE;
1451 }
1452
1453 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1454 {
1455 void *hdr;
1456 int rc;
1457
1458 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1459 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1460 if (!hdr)
1461 return -EMSGSIZE;
1462
1463 rc = net_dm_stats_put(msg);
1464 if (rc)
1465 goto nla_put_failure;
1466
1467 rc = net_dm_hw_stats_put(msg);
1468 if (rc)
1469 goto nla_put_failure;
1470
1471 genlmsg_end(msg, hdr);
1472
1473 return 0;
1474
1475 nla_put_failure:
1476 genlmsg_cancel(msg, hdr);
1477 return -EMSGSIZE;
1478 }
1479
1480 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1481 {
1482 struct sk_buff *msg;
1483 int rc;
1484
1485 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1486 if (!msg)
1487 return -ENOMEM;
1488
1489 rc = net_dm_stats_fill(msg, info);
1490 if (rc)
1491 goto free_msg;
1492
1493 return genlmsg_reply(msg, info);
1494
1495 free_msg:
1496 nlmsg_free(msg);
1497 return rc;
1498 }
1499
1500 static int dropmon_net_event(struct notifier_block *ev_block,
1501 unsigned long event, void *ptr)
1502 {
1503 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1504 struct dm_hw_stat_delta *new_stat = NULL;
1505 struct dm_hw_stat_delta *tmp;
1506
1507 switch (event) {
1508 case NETDEV_REGISTER:
1509 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
1510
1511 if (!new_stat)
1512 goto out;
1513
1514 new_stat->dev = dev;
1515 new_stat->last_rx = jiffies;
1516 mutex_lock(&net_dm_mutex);
1517 list_add_rcu(&new_stat->list, &hw_stats_list);
1518 mutex_unlock(&net_dm_mutex);
1519 break;
1520 case NETDEV_UNREGISTER:
1521 mutex_lock(&net_dm_mutex);
1522 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
1523 if (new_stat->dev == dev) {
1524 new_stat->dev = NULL;
1525 if (trace_state == TRACE_OFF) {
1526 list_del_rcu(&new_stat->list);
1527 kfree_rcu(new_stat, rcu);
1528 break;
1529 }
1530 }
1531 }
1532 mutex_unlock(&net_dm_mutex);
1533 break;
1534 }
1535 out:
1536 return NOTIFY_DONE;
1537 }
1538
1539 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1540 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1541 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1542 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1543 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1544 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG },
1545 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG },
1546 };
1547
1548 static const struct genl_ops dropmon_ops[] = {
1549 {
1550 .cmd = NET_DM_CMD_CONFIG,
1551 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1552 .doit = net_dm_cmd_config,
1553 .flags = GENL_ADMIN_PERM,
1554 },
1555 {
1556 .cmd = NET_DM_CMD_START,
1557 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1558 .doit = net_dm_cmd_trace,
1559 },
1560 {
1561 .cmd = NET_DM_CMD_STOP,
1562 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1563 .doit = net_dm_cmd_trace,
1564 },
1565 {
1566 .cmd = NET_DM_CMD_CONFIG_GET,
1567 .doit = net_dm_cmd_config_get,
1568 },
1569 {
1570 .cmd = NET_DM_CMD_STATS_GET,
1571 .doit = net_dm_cmd_stats_get,
1572 },
1573 };
1574
1575 static int net_dm_nl_pre_doit(const struct genl_ops *ops,
1576 struct sk_buff *skb, struct genl_info *info)
1577 {
1578 mutex_lock(&net_dm_mutex);
1579
1580 return 0;
1581 }
1582
1583 static void net_dm_nl_post_doit(const struct genl_ops *ops,
1584 struct sk_buff *skb, struct genl_info *info)
1585 {
1586 mutex_unlock(&net_dm_mutex);
1587 }
1588
1589 static struct genl_family net_drop_monitor_family __ro_after_init = {
1590 .hdrsize = 0,
1591 .name = "NET_DM",
1592 .version = 2,
1593 .maxattr = NET_DM_ATTR_MAX,
1594 .policy = net_dm_nl_policy,
1595 .pre_doit = net_dm_nl_pre_doit,
1596 .post_doit = net_dm_nl_post_doit,
1597 .module = THIS_MODULE,
1598 .ops = dropmon_ops,
1599 .n_ops = ARRAY_SIZE(dropmon_ops),
1600 .mcgrps = dropmon_mcgrps,
1601 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps),
1602 };
1603
1604 static struct notifier_block dropmon_net_notifier = {
1605 .notifier_call = dropmon_net_event
1606 };
1607
1608 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1609 {
1610 spin_lock_init(&data->lock);
1611 skb_queue_head_init(&data->drop_queue);
1612 u64_stats_init(&data->stats.syncp);
1613 }
1614
1615 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1616 {
1617 WARN_ON(!skb_queue_empty(&data->drop_queue));
1618 }
1619
1620 static void net_dm_cpu_data_init(int cpu)
1621 {
1622 struct per_cpu_dm_data *data;
1623
1624 data = &per_cpu(dm_cpu_data, cpu);
1625 __net_dm_cpu_data_init(data);
1626 }
1627
1628 static void net_dm_cpu_data_fini(int cpu)
1629 {
1630 struct per_cpu_dm_data *data;
1631
1632 data = &per_cpu(dm_cpu_data, cpu);
1633 /* At this point, we should have exclusive access
1634 * to this struct and can free the skb inside it.
1635 */
1636 consume_skb(data->skb);
1637 __net_dm_cpu_data_fini(data);
1638 }
1639
1640 static void net_dm_hw_cpu_data_init(int cpu)
1641 {
1642 struct per_cpu_dm_data *hw_data;
1643
1644 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1645 __net_dm_cpu_data_init(hw_data);
1646 }
1647
1648 static void net_dm_hw_cpu_data_fini(int cpu)
1649 {
1650 struct per_cpu_dm_data *hw_data;
1651
1652 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1653 kfree(hw_data->hw_entries);
1654 __net_dm_cpu_data_fini(hw_data);
1655 }
1656
1657 static int __init init_net_drop_monitor(void)
1658 {
1659 int cpu, rc;
1660
1661 pr_info("Initializing network drop monitor service\n");
1662
1663 if (sizeof(void *) > 8) {
1664 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1665 return -ENOSPC;
1666 }
1667
1668 rc = genl_register_family(&net_drop_monitor_family);
1669 if (rc) {
1670 pr_err("Could not create drop monitor netlink family\n");
1671 return rc;
1672 }
1673 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1674
1675 rc = register_netdevice_notifier(&dropmon_net_notifier);
1676 if (rc < 0) {
1677 pr_crit("Failed to register netdevice notifier\n");
1678 goto out_unreg;
1679 }
1680
1681 rc = 0;
1682
1683 for_each_possible_cpu(cpu) {
1684 net_dm_cpu_data_init(cpu);
1685 net_dm_hw_cpu_data_init(cpu);
1686 }
1687
1688 goto out;
1689
1690 out_unreg:
1691 genl_unregister_family(&net_drop_monitor_family);
1692 out:
1693 return rc;
1694 }
1695
1696 static void exit_net_drop_monitor(void)
1697 {
1698 int cpu;
1699
1700 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1701
1702 /*
1703 * Because of the module_get/put we do in the trace state change path
1704 * we are guarnateed not to have any current users when we get here
1705 */
1706
1707 for_each_possible_cpu(cpu) {
1708 net_dm_hw_cpu_data_fini(cpu);
1709 net_dm_cpu_data_fini(cpu);
1710 }
1711
1712 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1713 }
1714
1715 module_init(init_net_drop_monitor);
1716 module_exit(exit_net_drop_monitor);
1717
1718 MODULE_LICENSE("GPL v2");
1719 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1720 MODULE_ALIAS_GENL_FAMILY("NET_DM");
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