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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/bitfield.h>
25#include <linux/percpu.h>
26#include <linux/timer.h>
27#include <linux/bitops.h>
28#include <linux/slab.h>
29#include <linux/module.h>
30#include <net/genetlink.h>
31#include <net/netevent.h>
32#include <net/flow_offload.h>
33#include <net/dropreason.h>
34#include <net/devlink.h>
35
36#include <trace/events/skb.h>
37#include <trace/events/napi.h>
38#include <trace/events/devlink.h>
39
40#include <asm/unaligned.h>
41
42#define TRACE_ON 1
43#define TRACE_OFF 0
44
45/*
46 * Globals, our netlink socket pointer
47 * and the work handle that will send up
48 * netlink alerts
49 */
50static int trace_state = TRACE_OFF;
51static bool monitor_hw;
52
53/* net_dm_mutex
54 *
55 * An overall lock guarding every operation coming from userspace.
56 */
57static DEFINE_MUTEX(net_dm_mutex);
58
59struct net_dm_stats {
60 u64_stats_t dropped;
61 struct u64_stats_sync syncp;
62};
63
64#define NET_DM_MAX_HW_TRAP_NAME_LEN 40
65
66struct net_dm_hw_entry {
67 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
68 u32 count;
69};
70
71struct net_dm_hw_entries {
72 u32 num_entries;
73 struct net_dm_hw_entry entries[];
74};
75
76struct per_cpu_dm_data {
77 spinlock_t lock; /* Protects 'skb', 'hw_entries' and
78 * 'send_timer'
79 */
80 union {
81 struct sk_buff *skb;
82 struct net_dm_hw_entries *hw_entries;
83 };
84 struct sk_buff_head drop_queue;
85 struct work_struct dm_alert_work;
86 struct timer_list send_timer;
87 struct net_dm_stats stats;
88};
89
90struct dm_hw_stat_delta {
91 unsigned long last_rx;
92 unsigned long last_drop_val;
93 struct rcu_head rcu;
94};
95
96static struct genl_family net_drop_monitor_family;
97
98static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
99static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
100
101static int dm_hit_limit = 64;
102static int dm_delay = 1;
103static unsigned long dm_hw_check_delta = 2*HZ;
104
105static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
106static u32 net_dm_trunc_len;
107static u32 net_dm_queue_len = 1000;
108
109struct net_dm_alert_ops {
110 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
111 void *location,
112 enum skb_drop_reason reason);
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_trap_probe)(void *ignore, const struct devlink *devlink,
118 struct sk_buff *skb,
119 const struct devlink_trap_metadata *metadata);
120};
121
122struct net_dm_skb_cb {
123 union {
124 struct devlink_trap_metadata *hw_metadata;
125 void *pc;
126 };
127 enum skb_drop_reason reason;
128};
129
130#define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
131
132static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
133{
134 size_t al;
135 struct net_dm_alert_msg *msg;
136 struct nlattr *nla;
137 struct sk_buff *skb;
138 unsigned long flags;
139 void *msg_header;
140
141 al = sizeof(struct net_dm_alert_msg);
142 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
143 al += sizeof(struct nlattr);
144
145 skb = genlmsg_new(al, GFP_KERNEL);
146
147 if (!skb)
148 goto err;
149
150 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
151 0, NET_DM_CMD_ALERT);
152 if (!msg_header) {
153 nlmsg_free(skb);
154 skb = NULL;
155 goto err;
156 }
157 nla = nla_reserve(skb, NLA_UNSPEC,
158 sizeof(struct net_dm_alert_msg));
159 if (!nla) {
160 nlmsg_free(skb);
161 skb = NULL;
162 goto err;
163 }
164 msg = nla_data(nla);
165 memset(msg, 0, al);
166 goto out;
167
168err:
169 mod_timer(&data->send_timer, jiffies + HZ / 10);
170out:
171 spin_lock_irqsave(&data->lock, flags);
172 swap(data->skb, skb);
173 spin_unlock_irqrestore(&data->lock, flags);
174
175 if (skb) {
176 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
177 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
178
179 genlmsg_end(skb, genlmsg_data(gnlh));
180 }
181
182 return skb;
183}
184
185static const struct genl_multicast_group dropmon_mcgrps[] = {
186 { .name = "events", .flags = GENL_MCAST_CAP_SYS_ADMIN, },
187};
188
189static void send_dm_alert(struct work_struct *work)
190{
191 struct sk_buff *skb;
192 struct per_cpu_dm_data *data;
193
194 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
195
196 skb = reset_per_cpu_data(data);
197
198 if (skb)
199 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
200 0, GFP_KERNEL);
201}
202
203/*
204 * This is the timer function to delay the sending of an alert
205 * in the event that more drops will arrive during the
206 * hysteresis period.
207 */
208static void sched_send_work(struct timer_list *t)
209{
210 struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
211
212 schedule_work(&data->dm_alert_work);
213}
214
215static void trace_drop_common(struct sk_buff *skb, void *location)
216{
217 struct net_dm_alert_msg *msg;
218 struct net_dm_drop_point *point;
219 struct nlmsghdr *nlh;
220 struct nlattr *nla;
221 int i;
222 struct sk_buff *dskb;
223 struct per_cpu_dm_data *data;
224 unsigned long flags;
225
226 local_irq_save(flags);
227 data = this_cpu_ptr(&dm_cpu_data);
228 spin_lock(&data->lock);
229 dskb = data->skb;
230
231 if (!dskb)
232 goto out;
233
234 nlh = (struct nlmsghdr *)dskb->data;
235 nla = genlmsg_data(nlmsg_data(nlh));
236 msg = nla_data(nla);
237 point = msg->points;
238 for (i = 0; i < msg->entries; i++) {
239 if (!memcmp(&location, &point->pc, sizeof(void *))) {
240 point->count++;
241 goto out;
242 }
243 point++;
244 }
245 if (msg->entries == dm_hit_limit)
246 goto out;
247 /*
248 * We need to create a new entry
249 */
250 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
251 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
252 memcpy(point->pc, &location, sizeof(void *));
253 point->count = 1;
254 msg->entries++;
255
256 if (!timer_pending(&data->send_timer)) {
257 data->send_timer.expires = jiffies + dm_delay * HZ;
258 add_timer(&data->send_timer);
259 }
260
261out:
262 spin_unlock_irqrestore(&data->lock, flags);
263}
264
265static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
266 void *location,
267 enum skb_drop_reason reason)
268{
269 trace_drop_common(skb, location);
270}
271
272static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
273 int work, int budget)
274{
275 struct net_device *dev = napi->dev;
276 struct dm_hw_stat_delta *stat;
277 /*
278 * Don't check napi structures with no associated device
279 */
280 if (!dev)
281 return;
282
283 rcu_read_lock();
284 stat = rcu_dereference(dev->dm_private);
285 if (stat) {
286 /*
287 * only add a note to our monitor buffer if:
288 * 1) its after the last_rx delta
289 * 2) our rx_dropped count has gone up
290 */
291 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) &&
292 (dev->stats.rx_dropped != stat->last_drop_val)) {
293 trace_drop_common(NULL, NULL);
294 stat->last_drop_val = dev->stats.rx_dropped;
295 stat->last_rx = jiffies;
296 }
297 }
298 rcu_read_unlock();
299}
300
301static struct net_dm_hw_entries *
302net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
303{
304 struct net_dm_hw_entries *hw_entries;
305 unsigned long flags;
306
307 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
308 GFP_KERNEL);
309 if (!hw_entries) {
310 /* If the memory allocation failed, we try to perform another
311 * allocation in 1/10 second. Otherwise, the probe function
312 * will constantly bail out.
313 */
314 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
315 }
316
317 spin_lock_irqsave(&hw_data->lock, flags);
318 swap(hw_data->hw_entries, hw_entries);
319 spin_unlock_irqrestore(&hw_data->lock, flags);
320
321 return hw_entries;
322}
323
324static int net_dm_hw_entry_put(struct sk_buff *msg,
325 const struct net_dm_hw_entry *hw_entry)
326{
327 struct nlattr *attr;
328
329 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
330 if (!attr)
331 return -EMSGSIZE;
332
333 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
334 goto nla_put_failure;
335
336 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
337 goto nla_put_failure;
338
339 nla_nest_end(msg, attr);
340
341 return 0;
342
343nla_put_failure:
344 nla_nest_cancel(msg, attr);
345 return -EMSGSIZE;
346}
347
348static int net_dm_hw_entries_put(struct sk_buff *msg,
349 const struct net_dm_hw_entries *hw_entries)
350{
351 struct nlattr *attr;
352 int i;
353
354 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
355 if (!attr)
356 return -EMSGSIZE;
357
358 for (i = 0; i < hw_entries->num_entries; i++) {
359 int rc;
360
361 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
362 if (rc)
363 goto nla_put_failure;
364 }
365
366 nla_nest_end(msg, attr);
367
368 return 0;
369
370nla_put_failure:
371 nla_nest_cancel(msg, attr);
372 return -EMSGSIZE;
373}
374
375static int
376net_dm_hw_summary_report_fill(struct sk_buff *msg,
377 const struct net_dm_hw_entries *hw_entries)
378{
379 struct net_dm_alert_msg anc_hdr = { 0 };
380 void *hdr;
381 int rc;
382
383 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
384 NET_DM_CMD_ALERT);
385 if (!hdr)
386 return -EMSGSIZE;
387
388 /* We need to put the ancillary header in order not to break user
389 * space.
390 */
391 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
392 goto nla_put_failure;
393
394 rc = net_dm_hw_entries_put(msg, hw_entries);
395 if (rc)
396 goto nla_put_failure;
397
398 genlmsg_end(msg, hdr);
399
400 return 0;
401
402nla_put_failure:
403 genlmsg_cancel(msg, hdr);
404 return -EMSGSIZE;
405}
406
407static void net_dm_hw_summary_work(struct work_struct *work)
408{
409 struct net_dm_hw_entries *hw_entries;
410 struct per_cpu_dm_data *hw_data;
411 struct sk_buff *msg;
412 int rc;
413
414 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
415
416 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
417 if (!hw_entries)
418 return;
419
420 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
421 if (!msg)
422 goto out;
423
424 rc = net_dm_hw_summary_report_fill(msg, hw_entries);
425 if (rc) {
426 nlmsg_free(msg);
427 goto out;
428 }
429
430 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
431
432out:
433 kfree(hw_entries);
434}
435
436static void
437net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
438 struct sk_buff *skb,
439 const struct devlink_trap_metadata *metadata)
440{
441 struct net_dm_hw_entries *hw_entries;
442 struct net_dm_hw_entry *hw_entry;
443 struct per_cpu_dm_data *hw_data;
444 unsigned long flags;
445 int i;
446
447 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
448 return;
449
450 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
451 spin_lock_irqsave(&hw_data->lock, flags);
452 hw_entries = hw_data->hw_entries;
453
454 if (!hw_entries)
455 goto out;
456
457 for (i = 0; i < hw_entries->num_entries; i++) {
458 hw_entry = &hw_entries->entries[i];
459 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
460 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
461 hw_entry->count++;
462 goto out;
463 }
464 }
465 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
466 goto out;
467
468 hw_entry = &hw_entries->entries[hw_entries->num_entries];
469 strscpy(hw_entry->trap_name, metadata->trap_name,
470 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
471 hw_entry->count = 1;
472 hw_entries->num_entries++;
473
474 if (!timer_pending(&hw_data->send_timer)) {
475 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
476 add_timer(&hw_data->send_timer);
477 }
478
479out:
480 spin_unlock_irqrestore(&hw_data->lock, flags);
481}
482
483static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
484 .kfree_skb_probe = trace_kfree_skb_hit,
485 .napi_poll_probe = trace_napi_poll_hit,
486 .work_item_func = send_dm_alert,
487 .hw_work_item_func = net_dm_hw_summary_work,
488 .hw_trap_probe = net_dm_hw_trap_summary_probe,
489};
490
491static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
492 struct sk_buff *skb,
493 void *location,
494 enum skb_drop_reason reason)
495{
496 ktime_t tstamp = ktime_get_real();
497 struct per_cpu_dm_data *data;
498 struct net_dm_skb_cb *cb;
499 struct sk_buff *nskb;
500 unsigned long flags;
501
502 if (!skb_mac_header_was_set(skb))
503 return;
504
505 nskb = skb_clone(skb, GFP_ATOMIC);
506 if (!nskb)
507 return;
508
509 cb = NET_DM_SKB_CB(nskb);
510 cb->reason = reason;
511 cb->pc = location;
512 /* Override the timestamp because we care about the time when the
513 * packet was dropped.
514 */
515 nskb->tstamp = tstamp;
516
517 data = this_cpu_ptr(&dm_cpu_data);
518
519 spin_lock_irqsave(&data->drop_queue.lock, flags);
520 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
521 __skb_queue_tail(&data->drop_queue, nskb);
522 else
523 goto unlock_free;
524 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
525
526 schedule_work(&data->dm_alert_work);
527
528 return;
529
530unlock_free:
531 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
532 u64_stats_update_begin(&data->stats.syncp);
533 u64_stats_inc(&data->stats.dropped);
534 u64_stats_update_end(&data->stats.syncp);
535 consume_skb(nskb);
536}
537
538static void net_dm_packet_trace_napi_poll_hit(void *ignore,
539 struct napi_struct *napi,
540 int work, int budget)
541{
542}
543
544static size_t net_dm_in_port_size(void)
545{
546 /* NET_DM_ATTR_IN_PORT nest */
547 return nla_total_size(0) +
548 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
549 nla_total_size(sizeof(u32)) +
550 /* NET_DM_ATTR_PORT_NETDEV_NAME */
551 nla_total_size(IFNAMSIZ + 1);
552}
553
554#define NET_DM_MAX_SYMBOL_LEN 40
555#define NET_DM_MAX_REASON_LEN 50
556
557static size_t net_dm_packet_report_size(size_t payload_len)
558{
559 size_t size;
560
561 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
562
563 return NLMSG_ALIGN(size) +
564 /* NET_DM_ATTR_ORIGIN */
565 nla_total_size(sizeof(u16)) +
566 /* NET_DM_ATTR_PC */
567 nla_total_size(sizeof(u64)) +
568 /* NET_DM_ATTR_SYMBOL */
569 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
570 /* NET_DM_ATTR_IN_PORT */
571 net_dm_in_port_size() +
572 /* NET_DM_ATTR_TIMESTAMP */
573 nla_total_size(sizeof(u64)) +
574 /* NET_DM_ATTR_ORIG_LEN */
575 nla_total_size(sizeof(u32)) +
576 /* NET_DM_ATTR_PROTO */
577 nla_total_size(sizeof(u16)) +
578 /* NET_DM_ATTR_REASON */
579 nla_total_size(NET_DM_MAX_REASON_LEN + 1) +
580 /* NET_DM_ATTR_PAYLOAD */
581 nla_total_size(payload_len);
582}
583
584static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
585 const char *name)
586{
587 struct nlattr *attr;
588
589 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
590 if (!attr)
591 return -EMSGSIZE;
592
593 if (ifindex &&
594 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
595 goto nla_put_failure;
596
597 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
598 goto nla_put_failure;
599
600 nla_nest_end(msg, attr);
601
602 return 0;
603
604nla_put_failure:
605 nla_nest_cancel(msg, attr);
606 return -EMSGSIZE;
607}
608
609static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
610 size_t payload_len)
611{
612 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
613 const struct drop_reason_list *list = NULL;
614 unsigned int subsys, subsys_reason;
615 char buf[NET_DM_MAX_SYMBOL_LEN];
616 struct nlattr *attr;
617 void *hdr;
618 int rc;
619
620 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
621 NET_DM_CMD_PACKET_ALERT);
622 if (!hdr)
623 return -EMSGSIZE;
624
625 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
626 goto nla_put_failure;
627
628 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc,
629 NET_DM_ATTR_PAD))
630 goto nla_put_failure;
631
632 rcu_read_lock();
633 subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK);
634 if (subsys < SKB_DROP_REASON_SUBSYS_NUM)
635 list = rcu_dereference(drop_reasons_by_subsys[subsys]);
636 subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK;
637 if (!list ||
638 subsys_reason >= list->n_reasons ||
639 !list->reasons[subsys_reason] ||
640 strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) {
641 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]);
642 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED;
643 }
644 if (nla_put_string(msg, NET_DM_ATTR_REASON,
645 list->reasons[subsys_reason])) {
646 rcu_read_unlock();
647 goto nla_put_failure;
648 }
649 rcu_read_unlock();
650
651 snprintf(buf, sizeof(buf), "%pS", cb->pc);
652 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
653 goto nla_put_failure;
654
655 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
656 if (rc)
657 goto nla_put_failure;
658
659 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
660 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
661 goto nla_put_failure;
662
663 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
664 goto nla_put_failure;
665
666 if (!payload_len)
667 goto out;
668
669 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
670 goto nla_put_failure;
671
672 attr = skb_put(msg, nla_total_size(payload_len));
673 attr->nla_type = NET_DM_ATTR_PAYLOAD;
674 attr->nla_len = nla_attr_size(payload_len);
675 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
676 goto nla_put_failure;
677
678out:
679 genlmsg_end(msg, hdr);
680
681 return 0;
682
683nla_put_failure:
684 genlmsg_cancel(msg, hdr);
685 return -EMSGSIZE;
686}
687
688#define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
689
690static void net_dm_packet_report(struct sk_buff *skb)
691{
692 struct sk_buff *msg;
693 size_t payload_len;
694 int rc;
695
696 /* Make sure we start copying the packet from the MAC header */
697 if (skb->data > skb_mac_header(skb))
698 skb_push(skb, skb->data - skb_mac_header(skb));
699 else
700 skb_pull(skb, skb_mac_header(skb) - skb->data);
701
702 /* Ensure packet fits inside a single netlink attribute */
703 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
704 if (net_dm_trunc_len)
705 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
706
707 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
708 if (!msg)
709 goto out;
710
711 rc = net_dm_packet_report_fill(msg, skb, payload_len);
712 if (rc) {
713 nlmsg_free(msg);
714 goto out;
715 }
716
717 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
718
719out:
720 consume_skb(skb);
721}
722
723static void net_dm_packet_work(struct work_struct *work)
724{
725 struct per_cpu_dm_data *data;
726 struct sk_buff_head list;
727 struct sk_buff *skb;
728 unsigned long flags;
729
730 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
731
732 __skb_queue_head_init(&list);
733
734 spin_lock_irqsave(&data->drop_queue.lock, flags);
735 skb_queue_splice_tail_init(&data->drop_queue, &list);
736 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
737
738 while ((skb = __skb_dequeue(&list)))
739 net_dm_packet_report(skb);
740}
741
742static size_t
743net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
744{
745 return hw_metadata->fa_cookie ?
746 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
747}
748
749static size_t
750net_dm_hw_packet_report_size(size_t payload_len,
751 const struct devlink_trap_metadata *hw_metadata)
752{
753 size_t size;
754
755 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
756
757 return NLMSG_ALIGN(size) +
758 /* NET_DM_ATTR_ORIGIN */
759 nla_total_size(sizeof(u16)) +
760 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
761 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
762 /* NET_DM_ATTR_HW_TRAP_NAME */
763 nla_total_size(strlen(hw_metadata->trap_name) + 1) +
764 /* NET_DM_ATTR_IN_PORT */
765 net_dm_in_port_size() +
766 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
767 net_dm_flow_action_cookie_size(hw_metadata) +
768 /* NET_DM_ATTR_TIMESTAMP */
769 nla_total_size(sizeof(u64)) +
770 /* NET_DM_ATTR_ORIG_LEN */
771 nla_total_size(sizeof(u32)) +
772 /* NET_DM_ATTR_PROTO */
773 nla_total_size(sizeof(u16)) +
774 /* NET_DM_ATTR_PAYLOAD */
775 nla_total_size(payload_len);
776}
777
778static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
779 struct sk_buff *skb, size_t payload_len)
780{
781 struct devlink_trap_metadata *hw_metadata;
782 struct nlattr *attr;
783 void *hdr;
784
785 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
786
787 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
788 NET_DM_CMD_PACKET_ALERT);
789 if (!hdr)
790 return -EMSGSIZE;
791
792 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
793 goto nla_put_failure;
794
795 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
796 hw_metadata->trap_group_name))
797 goto nla_put_failure;
798
799 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
800 hw_metadata->trap_name))
801 goto nla_put_failure;
802
803 if (hw_metadata->input_dev) {
804 struct net_device *dev = hw_metadata->input_dev;
805 int rc;
806
807 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
808 dev->name);
809 if (rc)
810 goto nla_put_failure;
811 }
812
813 if (hw_metadata->fa_cookie &&
814 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
815 hw_metadata->fa_cookie->cookie_len,
816 hw_metadata->fa_cookie->cookie))
817 goto nla_put_failure;
818
819 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
820 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
821 goto nla_put_failure;
822
823 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
824 goto nla_put_failure;
825
826 if (!payload_len)
827 goto out;
828
829 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
830 goto nla_put_failure;
831
832 attr = skb_put(msg, nla_total_size(payload_len));
833 attr->nla_type = NET_DM_ATTR_PAYLOAD;
834 attr->nla_len = nla_attr_size(payload_len);
835 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
836 goto nla_put_failure;
837
838out:
839 genlmsg_end(msg, hdr);
840
841 return 0;
842
843nla_put_failure:
844 genlmsg_cancel(msg, hdr);
845 return -EMSGSIZE;
846}
847
848static struct devlink_trap_metadata *
849net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
850{
851 const struct flow_action_cookie *fa_cookie;
852 struct devlink_trap_metadata *hw_metadata;
853 const char *trap_group_name;
854 const char *trap_name;
855
856 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
857 if (!hw_metadata)
858 return NULL;
859
860 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
861 if (!trap_group_name)
862 goto free_hw_metadata;
863 hw_metadata->trap_group_name = trap_group_name;
864
865 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
866 if (!trap_name)
867 goto free_trap_group;
868 hw_metadata->trap_name = trap_name;
869
870 if (metadata->fa_cookie) {
871 size_t cookie_size = sizeof(*fa_cookie) +
872 metadata->fa_cookie->cookie_len;
873
874 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
875 GFP_ATOMIC);
876 if (!fa_cookie)
877 goto free_trap_name;
878 hw_metadata->fa_cookie = fa_cookie;
879 }
880
881 hw_metadata->input_dev = metadata->input_dev;
882 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker,
883 GFP_ATOMIC);
884
885 return hw_metadata;
886
887free_trap_name:
888 kfree(trap_name);
889free_trap_group:
890 kfree(trap_group_name);
891free_hw_metadata:
892 kfree(hw_metadata);
893 return NULL;
894}
895
896static void
897net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
898{
899 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker);
900 kfree(hw_metadata->fa_cookie);
901 kfree(hw_metadata->trap_name);
902 kfree(hw_metadata->trap_group_name);
903 kfree(hw_metadata);
904}
905
906static void net_dm_hw_packet_report(struct sk_buff *skb)
907{
908 struct devlink_trap_metadata *hw_metadata;
909 struct sk_buff *msg;
910 size_t payload_len;
911 int rc;
912
913 if (skb->data > skb_mac_header(skb))
914 skb_push(skb, skb->data - skb_mac_header(skb));
915 else
916 skb_pull(skb, skb_mac_header(skb) - skb->data);
917
918 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
919 if (net_dm_trunc_len)
920 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
921
922 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
923 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
924 GFP_KERNEL);
925 if (!msg)
926 goto out;
927
928 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
929 if (rc) {
930 nlmsg_free(msg);
931 goto out;
932 }
933
934 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
935
936out:
937 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
938 consume_skb(skb);
939}
940
941static void net_dm_hw_packet_work(struct work_struct *work)
942{
943 struct per_cpu_dm_data *hw_data;
944 struct sk_buff_head list;
945 struct sk_buff *skb;
946 unsigned long flags;
947
948 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
949
950 __skb_queue_head_init(&list);
951
952 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
953 skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
954 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
955
956 while ((skb = __skb_dequeue(&list)))
957 net_dm_hw_packet_report(skb);
958}
959
960static void
961net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
962 struct sk_buff *skb,
963 const struct devlink_trap_metadata *metadata)
964{
965 struct devlink_trap_metadata *n_hw_metadata;
966 ktime_t tstamp = ktime_get_real();
967 struct per_cpu_dm_data *hw_data;
968 struct sk_buff *nskb;
969 unsigned long flags;
970
971 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
972 return;
973
974 if (!skb_mac_header_was_set(skb))
975 return;
976
977 nskb = skb_clone(skb, GFP_ATOMIC);
978 if (!nskb)
979 return;
980
981 n_hw_metadata = net_dm_hw_metadata_copy(metadata);
982 if (!n_hw_metadata)
983 goto free;
984
985 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
986 nskb->tstamp = tstamp;
987
988 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
989
990 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
991 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
992 __skb_queue_tail(&hw_data->drop_queue, nskb);
993 else
994 goto unlock_free;
995 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
996
997 schedule_work(&hw_data->dm_alert_work);
998
999 return;
1000
1001unlock_free:
1002 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
1003 u64_stats_update_begin(&hw_data->stats.syncp);
1004 u64_stats_inc(&hw_data->stats.dropped);
1005 u64_stats_update_end(&hw_data->stats.syncp);
1006 net_dm_hw_metadata_free(n_hw_metadata);
1007free:
1008 consume_skb(nskb);
1009}
1010
1011static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
1012 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
1013 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
1014 .work_item_func = net_dm_packet_work,
1015 .hw_work_item_func = net_dm_hw_packet_work,
1016 .hw_trap_probe = net_dm_hw_trap_packet_probe,
1017};
1018
1019static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1020 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
1021 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
1022};
1023
1024#if IS_ENABLED(CONFIG_NET_DEVLINK)
1025static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1026{
1027 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1028}
1029
1030static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1031{
1032 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1033 tracepoint_synchronize_unregister();
1034}
1035#else
1036static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1037{
1038 return -EOPNOTSUPP;
1039}
1040
1041static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1042{
1043}
1044#endif
1045
1046static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1047{
1048 const struct net_dm_alert_ops *ops;
1049 int cpu, rc;
1050
1051 if (monitor_hw) {
1052 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1053 return -EAGAIN;
1054 }
1055
1056 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1057
1058 if (!try_module_get(THIS_MODULE)) {
1059 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1060 return -ENODEV;
1061 }
1062
1063 for_each_possible_cpu(cpu) {
1064 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1065 struct net_dm_hw_entries *hw_entries;
1066
1067 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1068 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1069 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1070 kfree(hw_entries);
1071 }
1072
1073 rc = net_dm_hw_probe_register(ops);
1074 if (rc) {
1075 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1076 goto err_module_put;
1077 }
1078
1079 monitor_hw = true;
1080
1081 return 0;
1082
1083err_module_put:
1084 for_each_possible_cpu(cpu) {
1085 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1086 struct sk_buff *skb;
1087
1088 del_timer_sync(&hw_data->send_timer);
1089 cancel_work_sync(&hw_data->dm_alert_work);
1090 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1091 struct devlink_trap_metadata *hw_metadata;
1092
1093 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1094 net_dm_hw_metadata_free(hw_metadata);
1095 consume_skb(skb);
1096 }
1097 }
1098 module_put(THIS_MODULE);
1099 return rc;
1100}
1101
1102static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1103{
1104 const struct net_dm_alert_ops *ops;
1105 int cpu;
1106
1107 if (!monitor_hw) {
1108 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1109 return;
1110 }
1111
1112 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1113
1114 monitor_hw = false;
1115
1116 net_dm_hw_probe_unregister(ops);
1117
1118 for_each_possible_cpu(cpu) {
1119 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1120 struct sk_buff *skb;
1121
1122 del_timer_sync(&hw_data->send_timer);
1123 cancel_work_sync(&hw_data->dm_alert_work);
1124 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1125 struct devlink_trap_metadata *hw_metadata;
1126
1127 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1128 net_dm_hw_metadata_free(hw_metadata);
1129 consume_skb(skb);
1130 }
1131 }
1132
1133 module_put(THIS_MODULE);
1134}
1135
1136static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1137{
1138 const struct net_dm_alert_ops *ops;
1139 int cpu, rc;
1140
1141 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1142
1143 if (!try_module_get(THIS_MODULE)) {
1144 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1145 return -ENODEV;
1146 }
1147
1148 for_each_possible_cpu(cpu) {
1149 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1150 struct sk_buff *skb;
1151
1152 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1153 timer_setup(&data->send_timer, sched_send_work, 0);
1154 /* Allocate a new per-CPU skb for the summary alert message and
1155 * free the old one which might contain stale data from
1156 * previous tracing.
1157 */
1158 skb = reset_per_cpu_data(data);
1159 consume_skb(skb);
1160 }
1161
1162 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1163 if (rc) {
1164 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1165 goto err_module_put;
1166 }
1167
1168 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1169 if (rc) {
1170 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1171 goto err_unregister_trace;
1172 }
1173
1174 return 0;
1175
1176err_unregister_trace:
1177 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1178err_module_put:
1179 for_each_possible_cpu(cpu) {
1180 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1181 struct sk_buff *skb;
1182
1183 del_timer_sync(&data->send_timer);
1184 cancel_work_sync(&data->dm_alert_work);
1185 while ((skb = __skb_dequeue(&data->drop_queue)))
1186 consume_skb(skb);
1187 }
1188 module_put(THIS_MODULE);
1189 return rc;
1190}
1191
1192static void net_dm_trace_off_set(void)
1193{
1194 const struct net_dm_alert_ops *ops;
1195 int cpu;
1196
1197 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1198
1199 unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1200 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1201
1202 tracepoint_synchronize_unregister();
1203
1204 /* Make sure we do not send notifications to user space after request
1205 * to stop tracing returns.
1206 */
1207 for_each_possible_cpu(cpu) {
1208 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1209 struct sk_buff *skb;
1210
1211 del_timer_sync(&data->send_timer);
1212 cancel_work_sync(&data->dm_alert_work);
1213 while ((skb = __skb_dequeue(&data->drop_queue)))
1214 consume_skb(skb);
1215 }
1216
1217 module_put(THIS_MODULE);
1218}
1219
1220static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1221{
1222 int rc = 0;
1223
1224 if (state == trace_state) {
1225 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1226 return -EAGAIN;
1227 }
1228
1229 switch (state) {
1230 case TRACE_ON:
1231 rc = net_dm_trace_on_set(extack);
1232 break;
1233 case TRACE_OFF:
1234 net_dm_trace_off_set();
1235 break;
1236 default:
1237 rc = 1;
1238 break;
1239 }
1240
1241 if (!rc)
1242 trace_state = state;
1243 else
1244 rc = -EINPROGRESS;
1245
1246 return rc;
1247}
1248
1249static bool net_dm_is_monitoring(void)
1250{
1251 return trace_state == TRACE_ON || monitor_hw;
1252}
1253
1254static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1255 enum net_dm_alert_mode *p_alert_mode)
1256{
1257 u8 val;
1258
1259 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1260
1261 switch (val) {
1262 case NET_DM_ALERT_MODE_SUMMARY:
1263 case NET_DM_ALERT_MODE_PACKET:
1264 *p_alert_mode = val;
1265 break;
1266 default:
1267 return -EINVAL;
1268 }
1269
1270 return 0;
1271}
1272
1273static int net_dm_alert_mode_set(struct genl_info *info)
1274{
1275 struct netlink_ext_ack *extack = info->extack;
1276 enum net_dm_alert_mode alert_mode;
1277 int rc;
1278
1279 if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1280 return 0;
1281
1282 rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1283 if (rc) {
1284 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1285 return -EINVAL;
1286 }
1287
1288 net_dm_alert_mode = alert_mode;
1289
1290 return 0;
1291}
1292
1293static void net_dm_trunc_len_set(struct genl_info *info)
1294{
1295 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1296 return;
1297
1298 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1299}
1300
1301static void net_dm_queue_len_set(struct genl_info *info)
1302{
1303 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1304 return;
1305
1306 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1307}
1308
1309static int net_dm_cmd_config(struct sk_buff *skb,
1310 struct genl_info *info)
1311{
1312 struct netlink_ext_ack *extack = info->extack;
1313 int rc;
1314
1315 if (net_dm_is_monitoring()) {
1316 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1317 return -EBUSY;
1318 }
1319
1320 rc = net_dm_alert_mode_set(info);
1321 if (rc)
1322 return rc;
1323
1324 net_dm_trunc_len_set(info);
1325
1326 net_dm_queue_len_set(info);
1327
1328 return 0;
1329}
1330
1331static int net_dm_monitor_start(bool set_sw, bool set_hw,
1332 struct netlink_ext_ack *extack)
1333{
1334 bool sw_set = false;
1335 int rc;
1336
1337 if (set_sw) {
1338 rc = set_all_monitor_traces(TRACE_ON, extack);
1339 if (rc)
1340 return rc;
1341 sw_set = true;
1342 }
1343
1344 if (set_hw) {
1345 rc = net_dm_hw_monitor_start(extack);
1346 if (rc)
1347 goto err_monitor_hw;
1348 }
1349
1350 return 0;
1351
1352err_monitor_hw:
1353 if (sw_set)
1354 set_all_monitor_traces(TRACE_OFF, extack);
1355 return rc;
1356}
1357
1358static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1359 struct netlink_ext_ack *extack)
1360{
1361 if (set_hw)
1362 net_dm_hw_monitor_stop(extack);
1363 if (set_sw)
1364 set_all_monitor_traces(TRACE_OFF, extack);
1365}
1366
1367static int net_dm_cmd_trace(struct sk_buff *skb,
1368 struct genl_info *info)
1369{
1370 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1371 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1372 struct netlink_ext_ack *extack = info->extack;
1373
1374 /* To maintain backward compatibility, we start / stop monitoring of
1375 * software drops if no flag is specified.
1376 */
1377 if (!set_sw && !set_hw)
1378 set_sw = true;
1379
1380 switch (info->genlhdr->cmd) {
1381 case NET_DM_CMD_START:
1382 return net_dm_monitor_start(set_sw, set_hw, extack);
1383 case NET_DM_CMD_STOP:
1384 net_dm_monitor_stop(set_sw, set_hw, extack);
1385 return 0;
1386 }
1387
1388 return -EOPNOTSUPP;
1389}
1390
1391static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1392{
1393 void *hdr;
1394
1395 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1396 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1397 if (!hdr)
1398 return -EMSGSIZE;
1399
1400 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1401 goto nla_put_failure;
1402
1403 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1404 goto nla_put_failure;
1405
1406 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1407 goto nla_put_failure;
1408
1409 genlmsg_end(msg, hdr);
1410
1411 return 0;
1412
1413nla_put_failure:
1414 genlmsg_cancel(msg, hdr);
1415 return -EMSGSIZE;
1416}
1417
1418static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1419{
1420 struct sk_buff *msg;
1421 int rc;
1422
1423 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1424 if (!msg)
1425 return -ENOMEM;
1426
1427 rc = net_dm_config_fill(msg, info);
1428 if (rc)
1429 goto free_msg;
1430
1431 return genlmsg_reply(msg, info);
1432
1433free_msg:
1434 nlmsg_free(msg);
1435 return rc;
1436}
1437
1438static void net_dm_stats_read(struct net_dm_stats *stats)
1439{
1440 int cpu;
1441
1442 memset(stats, 0, sizeof(*stats));
1443 for_each_possible_cpu(cpu) {
1444 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1445 struct net_dm_stats *cpu_stats = &data->stats;
1446 unsigned int start;
1447 u64 dropped;
1448
1449 do {
1450 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1451 dropped = u64_stats_read(&cpu_stats->dropped);
1452 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1453
1454 u64_stats_add(&stats->dropped, dropped);
1455 }
1456}
1457
1458static int net_dm_stats_put(struct sk_buff *msg)
1459{
1460 struct net_dm_stats stats;
1461 struct nlattr *attr;
1462
1463 net_dm_stats_read(&stats);
1464
1465 attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1466 if (!attr)
1467 return -EMSGSIZE;
1468
1469 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1470 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1471 goto nla_put_failure;
1472
1473 nla_nest_end(msg, attr);
1474
1475 return 0;
1476
1477nla_put_failure:
1478 nla_nest_cancel(msg, attr);
1479 return -EMSGSIZE;
1480}
1481
1482static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1483{
1484 int cpu;
1485
1486 memset(stats, 0, sizeof(*stats));
1487 for_each_possible_cpu(cpu) {
1488 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1489 struct net_dm_stats *cpu_stats = &hw_data->stats;
1490 unsigned int start;
1491 u64 dropped;
1492
1493 do {
1494 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1495 dropped = u64_stats_read(&cpu_stats->dropped);
1496 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1497
1498 u64_stats_add(&stats->dropped, dropped);
1499 }
1500}
1501
1502static int net_dm_hw_stats_put(struct sk_buff *msg)
1503{
1504 struct net_dm_stats stats;
1505 struct nlattr *attr;
1506
1507 net_dm_hw_stats_read(&stats);
1508
1509 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1510 if (!attr)
1511 return -EMSGSIZE;
1512
1513 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1514 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1515 goto nla_put_failure;
1516
1517 nla_nest_end(msg, attr);
1518
1519 return 0;
1520
1521nla_put_failure:
1522 nla_nest_cancel(msg, attr);
1523 return -EMSGSIZE;
1524}
1525
1526static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1527{
1528 void *hdr;
1529 int rc;
1530
1531 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1532 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1533 if (!hdr)
1534 return -EMSGSIZE;
1535
1536 rc = net_dm_stats_put(msg);
1537 if (rc)
1538 goto nla_put_failure;
1539
1540 rc = net_dm_hw_stats_put(msg);
1541 if (rc)
1542 goto nla_put_failure;
1543
1544 genlmsg_end(msg, hdr);
1545
1546 return 0;
1547
1548nla_put_failure:
1549 genlmsg_cancel(msg, hdr);
1550 return -EMSGSIZE;
1551}
1552
1553static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1554{
1555 struct sk_buff *msg;
1556 int rc;
1557
1558 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1559 if (!msg)
1560 return -ENOMEM;
1561
1562 rc = net_dm_stats_fill(msg, info);
1563 if (rc)
1564 goto free_msg;
1565
1566 return genlmsg_reply(msg, info);
1567
1568free_msg:
1569 nlmsg_free(msg);
1570 return rc;
1571}
1572
1573static int dropmon_net_event(struct notifier_block *ev_block,
1574 unsigned long event, void *ptr)
1575{
1576 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1577 struct dm_hw_stat_delta *stat;
1578
1579 switch (event) {
1580 case NETDEV_REGISTER:
1581 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1582 break;
1583 stat = kzalloc(sizeof(*stat), GFP_KERNEL);
1584 if (!stat)
1585 break;
1586
1587 stat->last_rx = jiffies;
1588 rcu_assign_pointer(dev->dm_private, stat);
1589
1590 break;
1591 case NETDEV_UNREGISTER:
1592 stat = rtnl_dereference(dev->dm_private);
1593 if (stat) {
1594 rcu_assign_pointer(dev->dm_private, NULL);
1595 kfree_rcu(stat, rcu);
1596 }
1597 break;
1598 }
1599 return NOTIFY_DONE;
1600}
1601
1602static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1603 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1604 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1605 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1606 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1607 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG },
1608 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG },
1609};
1610
1611static const struct genl_small_ops dropmon_ops[] = {
1612 {
1613 .cmd = NET_DM_CMD_CONFIG,
1614 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1615 .doit = net_dm_cmd_config,
1616 .flags = GENL_ADMIN_PERM,
1617 },
1618 {
1619 .cmd = NET_DM_CMD_START,
1620 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1621 .doit = net_dm_cmd_trace,
1622 .flags = GENL_ADMIN_PERM,
1623 },
1624 {
1625 .cmd = NET_DM_CMD_STOP,
1626 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1627 .doit = net_dm_cmd_trace,
1628 .flags = GENL_ADMIN_PERM,
1629 },
1630 {
1631 .cmd = NET_DM_CMD_CONFIG_GET,
1632 .doit = net_dm_cmd_config_get,
1633 },
1634 {
1635 .cmd = NET_DM_CMD_STATS_GET,
1636 .doit = net_dm_cmd_stats_get,
1637 },
1638};
1639
1640static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
1641 struct sk_buff *skb, struct genl_info *info)
1642{
1643 mutex_lock(&net_dm_mutex);
1644
1645 return 0;
1646}
1647
1648static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
1649 struct sk_buff *skb, struct genl_info *info)
1650{
1651 mutex_unlock(&net_dm_mutex);
1652}
1653
1654static struct genl_family net_drop_monitor_family __ro_after_init = {
1655 .hdrsize = 0,
1656 .name = "NET_DM",
1657 .version = 2,
1658 .maxattr = NET_DM_ATTR_MAX,
1659 .policy = net_dm_nl_policy,
1660 .pre_doit = net_dm_nl_pre_doit,
1661 .post_doit = net_dm_nl_post_doit,
1662 .module = THIS_MODULE,
1663 .small_ops = dropmon_ops,
1664 .n_small_ops = ARRAY_SIZE(dropmon_ops),
1665 .resv_start_op = NET_DM_CMD_STATS_GET + 1,
1666 .mcgrps = dropmon_mcgrps,
1667 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps),
1668};
1669
1670static struct notifier_block dropmon_net_notifier = {
1671 .notifier_call = dropmon_net_event
1672};
1673
1674static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1675{
1676 spin_lock_init(&data->lock);
1677 skb_queue_head_init(&data->drop_queue);
1678 u64_stats_init(&data->stats.syncp);
1679}
1680
1681static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1682{
1683 WARN_ON(!skb_queue_empty(&data->drop_queue));
1684}
1685
1686static void net_dm_cpu_data_init(int cpu)
1687{
1688 struct per_cpu_dm_data *data;
1689
1690 data = &per_cpu(dm_cpu_data, cpu);
1691 __net_dm_cpu_data_init(data);
1692}
1693
1694static void net_dm_cpu_data_fini(int cpu)
1695{
1696 struct per_cpu_dm_data *data;
1697
1698 data = &per_cpu(dm_cpu_data, cpu);
1699 /* At this point, we should have exclusive access
1700 * to this struct and can free the skb inside it.
1701 */
1702 consume_skb(data->skb);
1703 __net_dm_cpu_data_fini(data);
1704}
1705
1706static void net_dm_hw_cpu_data_init(int cpu)
1707{
1708 struct per_cpu_dm_data *hw_data;
1709
1710 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1711 __net_dm_cpu_data_init(hw_data);
1712}
1713
1714static void net_dm_hw_cpu_data_fini(int cpu)
1715{
1716 struct per_cpu_dm_data *hw_data;
1717
1718 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1719 kfree(hw_data->hw_entries);
1720 __net_dm_cpu_data_fini(hw_data);
1721}
1722
1723static int __init init_net_drop_monitor(void)
1724{
1725 int cpu, rc;
1726
1727 pr_info("Initializing network drop monitor service\n");
1728
1729 if (sizeof(void *) > 8) {
1730 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1731 return -ENOSPC;
1732 }
1733
1734 rc = genl_register_family(&net_drop_monitor_family);
1735 if (rc) {
1736 pr_err("Could not create drop monitor netlink family\n");
1737 return rc;
1738 }
1739 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1740
1741 rc = register_netdevice_notifier(&dropmon_net_notifier);
1742 if (rc < 0) {
1743 pr_crit("Failed to register netdevice notifier\n");
1744 goto out_unreg;
1745 }
1746
1747 rc = 0;
1748
1749 for_each_possible_cpu(cpu) {
1750 net_dm_cpu_data_init(cpu);
1751 net_dm_hw_cpu_data_init(cpu);
1752 }
1753
1754 goto out;
1755
1756out_unreg:
1757 genl_unregister_family(&net_drop_monitor_family);
1758out:
1759 return rc;
1760}
1761
1762static void exit_net_drop_monitor(void)
1763{
1764 int cpu;
1765
1766 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1767
1768 /*
1769 * Because of the module_get/put we do in the trace state change path
1770 * we are guaranteed not to have any current users when we get here
1771 */
1772
1773 for_each_possible_cpu(cpu) {
1774 net_dm_hw_cpu_data_fini(cpu);
1775 net_dm_cpu_data_fini(cpu);
1776 }
1777
1778 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1779}
1780
1781module_init(init_net_drop_monitor);
1782module_exit(exit_net_drop_monitor);
1783
1784MODULE_LICENSE("GPL v2");
1785MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1786MODULE_ALIAS_GENL_FAMILY("NET_DM");
1787MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");
1/*
2 * Monitoring code for network dropped packet alerts
3 *
4 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/netdevice.h>
10#include <linux/etherdevice.h>
11#include <linux/string.h>
12#include <linux/if_arp.h>
13#include <linux/inetdevice.h>
14#include <linux/inet.h>
15#include <linux/interrupt.h>
16#include <linux/netpoll.h>
17#include <linux/sched.h>
18#include <linux/delay.h>
19#include <linux/types.h>
20#include <linux/workqueue.h>
21#include <linux/netlink.h>
22#include <linux/net_dropmon.h>
23#include <linux/percpu.h>
24#include <linux/timer.h>
25#include <linux/bitops.h>
26#include <linux/slab.h>
27#include <linux/module.h>
28#include <net/genetlink.h>
29#include <net/netevent.h>
30
31#include <trace/events/skb.h>
32#include <trace/events/napi.h>
33
34#include <asm/unaligned.h>
35
36#define TRACE_ON 1
37#define TRACE_OFF 0
38
39/*
40 * Globals, our netlink socket pointer
41 * and the work handle that will send up
42 * netlink alerts
43 */
44static int trace_state = TRACE_OFF;
45static DEFINE_MUTEX(trace_state_mutex);
46
47struct per_cpu_dm_data {
48 spinlock_t lock;
49 struct sk_buff *skb;
50 struct work_struct dm_alert_work;
51 struct timer_list send_timer;
52};
53
54struct dm_hw_stat_delta {
55 struct net_device *dev;
56 unsigned long last_rx;
57 struct list_head list;
58 struct rcu_head rcu;
59 unsigned long last_drop_val;
60};
61
62static struct genl_family net_drop_monitor_family = {
63 .id = GENL_ID_GENERATE,
64 .hdrsize = 0,
65 .name = "NET_DM",
66 .version = 2,
67 .maxattr = NET_DM_CMD_MAX,
68};
69
70static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
71
72static int dm_hit_limit = 64;
73static int dm_delay = 1;
74static unsigned long dm_hw_check_delta = 2*HZ;
75static LIST_HEAD(hw_stats_list);
76
77static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
78{
79 size_t al;
80 struct net_dm_alert_msg *msg;
81 struct nlattr *nla;
82 struct sk_buff *skb;
83 unsigned long flags;
84
85 al = sizeof(struct net_dm_alert_msg);
86 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
87 al += sizeof(struct nlattr);
88
89 skb = genlmsg_new(al, GFP_KERNEL);
90
91 if (skb) {
92 genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
93 0, NET_DM_CMD_ALERT);
94 nla = nla_reserve(skb, NLA_UNSPEC,
95 sizeof(struct net_dm_alert_msg));
96 msg = nla_data(nla);
97 memset(msg, 0, al);
98 } else {
99 mod_timer(&data->send_timer, jiffies + HZ / 10);
100 }
101
102 spin_lock_irqsave(&data->lock, flags);
103 swap(data->skb, skb);
104 spin_unlock_irqrestore(&data->lock, flags);
105
106 return skb;
107}
108
109static void send_dm_alert(struct work_struct *work)
110{
111 struct sk_buff *skb;
112 struct per_cpu_dm_data *data;
113
114 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
115
116 skb = reset_per_cpu_data(data);
117
118 if (skb)
119 genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
120}
121
122/*
123 * This is the timer function to delay the sending of an alert
124 * in the event that more drops will arrive during the
125 * hysteresis period.
126 */
127static void sched_send_work(unsigned long _data)
128{
129 struct per_cpu_dm_data *data = (struct per_cpu_dm_data *)_data;
130
131 schedule_work(&data->dm_alert_work);
132}
133
134static void trace_drop_common(struct sk_buff *skb, void *location)
135{
136 struct net_dm_alert_msg *msg;
137 struct nlmsghdr *nlh;
138 struct nlattr *nla;
139 int i;
140 struct sk_buff *dskb;
141 struct per_cpu_dm_data *data;
142 unsigned long flags;
143
144 local_irq_save(flags);
145 data = &__get_cpu_var(dm_cpu_data);
146 spin_lock(&data->lock);
147 dskb = data->skb;
148
149 if (!dskb)
150 goto out;
151
152 nlh = (struct nlmsghdr *)dskb->data;
153 nla = genlmsg_data(nlmsg_data(nlh));
154 msg = nla_data(nla);
155 for (i = 0; i < msg->entries; i++) {
156 if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
157 msg->points[i].count++;
158 goto out;
159 }
160 }
161 if (msg->entries == dm_hit_limit)
162 goto out;
163 /*
164 * We need to create a new entry
165 */
166 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
167 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
168 memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
169 msg->points[msg->entries].count = 1;
170 msg->entries++;
171
172 if (!timer_pending(&data->send_timer)) {
173 data->send_timer.expires = jiffies + dm_delay * HZ;
174 add_timer(&data->send_timer);
175 }
176
177out:
178 spin_unlock_irqrestore(&data->lock, flags);
179}
180
181static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
182{
183 trace_drop_common(skb, location);
184}
185
186static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi)
187{
188 struct dm_hw_stat_delta *new_stat;
189
190 /*
191 * Don't check napi structures with no associated device
192 */
193 if (!napi->dev)
194 return;
195
196 rcu_read_lock();
197 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
198 /*
199 * only add a note to our monitor buffer if:
200 * 1) this is the dev we received on
201 * 2) its after the last_rx delta
202 * 3) our rx_dropped count has gone up
203 */
204 if ((new_stat->dev == napi->dev) &&
205 (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
206 (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
207 trace_drop_common(NULL, NULL);
208 new_stat->last_drop_val = napi->dev->stats.rx_dropped;
209 new_stat->last_rx = jiffies;
210 break;
211 }
212 }
213 rcu_read_unlock();
214}
215
216static int set_all_monitor_traces(int state)
217{
218 int rc = 0;
219 struct dm_hw_stat_delta *new_stat = NULL;
220 struct dm_hw_stat_delta *temp;
221
222 mutex_lock(&trace_state_mutex);
223
224 if (state == trace_state) {
225 rc = -EAGAIN;
226 goto out_unlock;
227 }
228
229 switch (state) {
230 case TRACE_ON:
231 if (!try_module_get(THIS_MODULE)) {
232 rc = -ENODEV;
233 break;
234 }
235
236 rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL);
237 rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL);
238 break;
239
240 case TRACE_OFF:
241 rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL);
242 rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL);
243
244 tracepoint_synchronize_unregister();
245
246 /*
247 * Clean the device list
248 */
249 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
250 if (new_stat->dev == NULL) {
251 list_del_rcu(&new_stat->list);
252 kfree_rcu(new_stat, rcu);
253 }
254 }
255
256 module_put(THIS_MODULE);
257
258 break;
259 default:
260 rc = 1;
261 break;
262 }
263
264 if (!rc)
265 trace_state = state;
266 else
267 rc = -EINPROGRESS;
268
269out_unlock:
270 mutex_unlock(&trace_state_mutex);
271
272 return rc;
273}
274
275
276static int net_dm_cmd_config(struct sk_buff *skb,
277 struct genl_info *info)
278{
279 return -ENOTSUPP;
280}
281
282static int net_dm_cmd_trace(struct sk_buff *skb,
283 struct genl_info *info)
284{
285 switch (info->genlhdr->cmd) {
286 case NET_DM_CMD_START:
287 return set_all_monitor_traces(TRACE_ON);
288 break;
289 case NET_DM_CMD_STOP:
290 return set_all_monitor_traces(TRACE_OFF);
291 break;
292 }
293
294 return -ENOTSUPP;
295}
296
297static int dropmon_net_event(struct notifier_block *ev_block,
298 unsigned long event, void *ptr)
299{
300 struct net_device *dev = ptr;
301 struct dm_hw_stat_delta *new_stat = NULL;
302 struct dm_hw_stat_delta *tmp;
303
304 switch (event) {
305 case NETDEV_REGISTER:
306 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
307
308 if (!new_stat)
309 goto out;
310
311 new_stat->dev = dev;
312 new_stat->last_rx = jiffies;
313 mutex_lock(&trace_state_mutex);
314 list_add_rcu(&new_stat->list, &hw_stats_list);
315 mutex_unlock(&trace_state_mutex);
316 break;
317 case NETDEV_UNREGISTER:
318 mutex_lock(&trace_state_mutex);
319 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
320 if (new_stat->dev == dev) {
321 new_stat->dev = NULL;
322 if (trace_state == TRACE_OFF) {
323 list_del_rcu(&new_stat->list);
324 kfree_rcu(new_stat, rcu);
325 break;
326 }
327 }
328 }
329 mutex_unlock(&trace_state_mutex);
330 break;
331 }
332out:
333 return NOTIFY_DONE;
334}
335
336static struct genl_ops dropmon_ops[] = {
337 {
338 .cmd = NET_DM_CMD_CONFIG,
339 .doit = net_dm_cmd_config,
340 },
341 {
342 .cmd = NET_DM_CMD_START,
343 .doit = net_dm_cmd_trace,
344 },
345 {
346 .cmd = NET_DM_CMD_STOP,
347 .doit = net_dm_cmd_trace,
348 },
349};
350
351static struct notifier_block dropmon_net_notifier = {
352 .notifier_call = dropmon_net_event
353};
354
355static int __init init_net_drop_monitor(void)
356{
357 struct per_cpu_dm_data *data;
358 int cpu, rc;
359
360 pr_info("Initializing network drop monitor service\n");
361
362 if (sizeof(void *) > 8) {
363 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
364 return -ENOSPC;
365 }
366
367 rc = genl_register_family_with_ops(&net_drop_monitor_family,
368 dropmon_ops,
369 ARRAY_SIZE(dropmon_ops));
370 if (rc) {
371 pr_err("Could not create drop monitor netlink family\n");
372 return rc;
373 }
374
375 rc = register_netdevice_notifier(&dropmon_net_notifier);
376 if (rc < 0) {
377 pr_crit("Failed to register netdevice notifier\n");
378 goto out_unreg;
379 }
380
381 rc = 0;
382
383 for_each_possible_cpu(cpu) {
384 data = &per_cpu(dm_cpu_data, cpu);
385 INIT_WORK(&data->dm_alert_work, send_dm_alert);
386 init_timer(&data->send_timer);
387 data->send_timer.data = (unsigned long)data;
388 data->send_timer.function = sched_send_work;
389 spin_lock_init(&data->lock);
390 reset_per_cpu_data(data);
391 }
392
393
394 goto out;
395
396out_unreg:
397 genl_unregister_family(&net_drop_monitor_family);
398out:
399 return rc;
400}
401
402static void exit_net_drop_monitor(void)
403{
404 struct per_cpu_dm_data *data;
405 int cpu;
406
407 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
408
409 /*
410 * Because of the module_get/put we do in the trace state change path
411 * we are guarnateed not to have any current users when we get here
412 * all we need to do is make sure that we don't have any running timers
413 * or pending schedule calls
414 */
415
416 for_each_possible_cpu(cpu) {
417 data = &per_cpu(dm_cpu_data, cpu);
418 del_timer_sync(&data->send_timer);
419 cancel_work_sync(&data->dm_alert_work);
420 /*
421 * At this point, we should have exclusive access
422 * to this struct and can free the skb inside it
423 */
424 kfree_skb(data->skb);
425 }
426
427 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
428}
429
430module_init(init_net_drop_monitor);
431module_exit(exit_net_drop_monitor);
432
433MODULE_LICENSE("GPL v2");
434MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
435MODULE_ALIAS_GENL_FAMILY("NET_DM");