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 <linux/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 */
50 static int trace_state = TRACE_OFF;
51 static bool monitor_hw;
52
53 /* net_dm_mutex
54 *
55 * An overall lock guarding every operation coming from userspace.
56 */
57 static DEFINE_MUTEX(net_dm_mutex);
58
59 struct 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
66 struct net_dm_hw_entry {
67 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
68 u32 count;
69 };
70
71 struct net_dm_hw_entries {
72 u32 num_entries;
73 struct net_dm_hw_entry entries[];
74 };
75
76 struct per_cpu_dm_data {
77 raw_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
90 struct dm_hw_stat_delta {
91 unsigned long last_rx;
92 unsigned long last_drop_val;
93 struct rcu_head rcu;
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
105 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
106 static u32 net_dm_trunc_len;
107 static u32 net_dm_queue_len = 1000;
108
109 struct 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 struct sock *rx_sk);
114 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
115 int work, int budget);
116 void (*work_item_func)(struct work_struct *work);
117 void (*hw_work_item_func)(struct work_struct *work);
118 void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
119 struct sk_buff *skb,
120 const struct devlink_trap_metadata *metadata);
121 };
122
123 struct net_dm_skb_cb {
124 union {
125 struct devlink_trap_metadata *hw_metadata;
126 void *pc;
127 };
128 enum skb_drop_reason reason;
129 };
130
131 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
132
reset_per_cpu_data(struct per_cpu_dm_data * data)133 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
134 {
135 size_t al;
136 struct net_dm_alert_msg *msg;
137 struct nlattr *nla;
138 struct sk_buff *skb;
139 unsigned long flags;
140 void *msg_header;
141
142 al = sizeof(struct net_dm_alert_msg);
143 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
144 al += sizeof(struct nlattr);
145
146 skb = genlmsg_new(al, GFP_KERNEL);
147
148 if (!skb)
149 goto err;
150
151 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
152 0, NET_DM_CMD_ALERT);
153 if (!msg_header) {
154 nlmsg_free(skb);
155 skb = NULL;
156 goto err;
157 }
158 nla = nla_reserve(skb, NLA_UNSPEC,
159 sizeof(struct net_dm_alert_msg));
160 if (!nla) {
161 nlmsg_free(skb);
162 skb = NULL;
163 goto err;
164 }
165 msg = nla_data(nla);
166 memset(msg, 0, al);
167 goto out;
168
169 err:
170 mod_timer(&data->send_timer, jiffies + HZ / 10);
171 out:
172 raw_spin_lock_irqsave(&data->lock, flags);
173 swap(data->skb, skb);
174 raw_spin_unlock_irqrestore(&data->lock, flags);
175
176 if (skb) {
177 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
178 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
179
180 genlmsg_end(skb, genlmsg_data(gnlh));
181 }
182
183 return skb;
184 }
185
186 static const struct genl_multicast_group dropmon_mcgrps[] = {
187 { .name = "events", .flags = GENL_MCAST_CAP_SYS_ADMIN, },
188 };
189
send_dm_alert(struct work_struct * work)190 static void send_dm_alert(struct work_struct *work)
191 {
192 struct sk_buff *skb;
193 struct per_cpu_dm_data *data;
194
195 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
196
197 skb = reset_per_cpu_data(data);
198
199 if (skb)
200 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
201 0, GFP_KERNEL);
202 }
203
204 /*
205 * This is the timer function to delay the sending of an alert
206 * in the event that more drops will arrive during the
207 * hysteresis period.
208 */
sched_send_work(struct timer_list * t)209 static void sched_send_work(struct timer_list *t)
210 {
211 struct per_cpu_dm_data *data = timer_container_of(data, t, send_timer);
212
213 schedule_work(&data->dm_alert_work);
214 }
215
trace_drop_common(struct sk_buff * skb,void * location)216 static void trace_drop_common(struct sk_buff *skb, void *location)
217 {
218 struct net_dm_alert_msg *msg;
219 struct net_dm_drop_point *point;
220 struct nlmsghdr *nlh;
221 struct nlattr *nla;
222 int i;
223 struct sk_buff *dskb;
224 struct per_cpu_dm_data *data;
225 unsigned long flags;
226
227 local_irq_save(flags);
228 data = this_cpu_ptr(&dm_cpu_data);
229 raw_spin_lock(&data->lock);
230 dskb = data->skb;
231
232 if (!dskb)
233 goto out;
234
235 nlh = (struct nlmsghdr *)dskb->data;
236 nla = genlmsg_data(nlmsg_data(nlh));
237 msg = nla_data(nla);
238 point = msg->points;
239 for (i = 0; i < msg->entries; i++) {
240 if (!memcmp(&location, &point->pc, sizeof(void *))) {
241 point->count++;
242 goto out;
243 }
244 point++;
245 }
246 if (msg->entries == dm_hit_limit)
247 goto out;
248 /*
249 * We need to create a new entry
250 */
251 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
252 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
253 memcpy(point->pc, &location, sizeof(void *));
254 point->count = 1;
255 msg->entries++;
256
257 if (!timer_pending(&data->send_timer)) {
258 data->send_timer.expires = jiffies + dm_delay * HZ;
259 add_timer(&data->send_timer);
260 }
261
262 out:
263 raw_spin_unlock_irqrestore(&data->lock, flags);
264 }
265
trace_kfree_skb_hit(void * ignore,struct sk_buff * skb,void * location,enum skb_drop_reason reason,struct sock * rx_sk)266 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
267 void *location,
268 enum skb_drop_reason reason,
269 struct sock *rx_sk)
270 {
271 trace_drop_common(skb, location);
272 }
273
trace_napi_poll_hit(void * ignore,struct napi_struct * napi,int work,int budget)274 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
275 int work, int budget)
276 {
277 struct net_device *dev = napi->dev;
278 struct dm_hw_stat_delta *stat;
279 /*
280 * Don't check napi structures with no associated device
281 */
282 if (!dev)
283 return;
284
285 rcu_read_lock();
286 stat = rcu_dereference(dev->dm_private);
287 if (stat) {
288 /*
289 * only add a note to our monitor buffer if:
290 * 1) its after the last_rx delta
291 * 2) our rx_dropped count has gone up
292 */
293 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) &&
294 (dev->stats.rx_dropped != stat->last_drop_val)) {
295 trace_drop_common(NULL, NULL);
296 stat->last_drop_val = dev->stats.rx_dropped;
297 stat->last_rx = jiffies;
298 }
299 }
300 rcu_read_unlock();
301 }
302
303 static struct net_dm_hw_entries *
net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data * hw_data)304 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
305 {
306 struct net_dm_hw_entries *hw_entries;
307 unsigned long flags;
308
309 hw_entries = kzalloc_flex(*hw_entries, entries, dm_hit_limit);
310 if (!hw_entries) {
311 /* If the memory allocation failed, we try to perform another
312 * allocation in 1/10 second. Otherwise, the probe function
313 * will constantly bail out.
314 */
315 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
316 }
317
318 raw_spin_lock_irqsave(&hw_data->lock, flags);
319 swap(hw_data->hw_entries, hw_entries);
320 raw_spin_unlock_irqrestore(&hw_data->lock, flags);
321
322 return hw_entries;
323 }
324
net_dm_hw_entry_put(struct sk_buff * msg,const struct net_dm_hw_entry * hw_entry)325 static int net_dm_hw_entry_put(struct sk_buff *msg,
326 const struct net_dm_hw_entry *hw_entry)
327 {
328 struct nlattr *attr;
329
330 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
331 if (!attr)
332 return -EMSGSIZE;
333
334 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
335 goto nla_put_failure;
336
337 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
338 goto nla_put_failure;
339
340 nla_nest_end(msg, attr);
341
342 return 0;
343
344 nla_put_failure:
345 nla_nest_cancel(msg, attr);
346 return -EMSGSIZE;
347 }
348
net_dm_hw_entries_put(struct sk_buff * msg,const struct net_dm_hw_entries * hw_entries)349 static int net_dm_hw_entries_put(struct sk_buff *msg,
350 const struct net_dm_hw_entries *hw_entries)
351 {
352 struct nlattr *attr;
353 int i;
354
355 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
356 if (!attr)
357 return -EMSGSIZE;
358
359 for (i = 0; i < hw_entries->num_entries; i++) {
360 int rc;
361
362 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
363 if (rc)
364 goto nla_put_failure;
365 }
366
367 nla_nest_end(msg, attr);
368
369 return 0;
370
371 nla_put_failure:
372 nla_nest_cancel(msg, attr);
373 return -EMSGSIZE;
374 }
375
376 static int
net_dm_hw_summary_report_fill(struct sk_buff * msg,const struct net_dm_hw_entries * hw_entries)377 net_dm_hw_summary_report_fill(struct sk_buff *msg,
378 const struct net_dm_hw_entries *hw_entries)
379 {
380 struct net_dm_alert_msg anc_hdr = { 0 };
381 void *hdr;
382 int rc;
383
384 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
385 NET_DM_CMD_ALERT);
386 if (!hdr)
387 return -EMSGSIZE;
388
389 /* We need to put the ancillary header in order not to break user
390 * space.
391 */
392 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
393 goto nla_put_failure;
394
395 rc = net_dm_hw_entries_put(msg, hw_entries);
396 if (rc)
397 goto nla_put_failure;
398
399 genlmsg_end(msg, hdr);
400
401 return 0;
402
403 nla_put_failure:
404 genlmsg_cancel(msg, hdr);
405 return -EMSGSIZE;
406 }
407
net_dm_hw_summary_work(struct work_struct * work)408 static void net_dm_hw_summary_work(struct work_struct *work)
409 {
410 struct net_dm_hw_entries *hw_entries;
411 struct per_cpu_dm_data *hw_data;
412 struct sk_buff *msg;
413 int rc;
414
415 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
416
417 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
418 if (!hw_entries)
419 return;
420
421 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
422 if (!msg)
423 goto out;
424
425 rc = net_dm_hw_summary_report_fill(msg, hw_entries);
426 if (rc) {
427 nlmsg_free(msg);
428 goto out;
429 }
430
431 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
432
433 out:
434 kfree(hw_entries);
435 }
436
437 static void
net_dm_hw_trap_summary_probe(void * ignore,const struct devlink * devlink,struct sk_buff * skb,const struct devlink_trap_metadata * metadata)438 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
439 struct sk_buff *skb,
440 const struct devlink_trap_metadata *metadata)
441 {
442 struct net_dm_hw_entries *hw_entries;
443 struct net_dm_hw_entry *hw_entry;
444 struct per_cpu_dm_data *hw_data;
445 unsigned long flags;
446 int i;
447
448 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
449 return;
450
451 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
452 raw_spin_lock_irqsave(&hw_data->lock, flags);
453 hw_entries = hw_data->hw_entries;
454
455 if (!hw_entries)
456 goto out;
457
458 for (i = 0; i < hw_entries->num_entries; i++) {
459 hw_entry = &hw_entries->entries[i];
460 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
461 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
462 hw_entry->count++;
463 goto out;
464 }
465 }
466 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
467 goto out;
468
469 hw_entry = &hw_entries->entries[hw_entries->num_entries];
470 strscpy(hw_entry->trap_name, metadata->trap_name,
471 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
472 hw_entry->count = 1;
473 hw_entries->num_entries++;
474
475 if (!timer_pending(&hw_data->send_timer)) {
476 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
477 add_timer(&hw_data->send_timer);
478 }
479
480 out:
481 raw_spin_unlock_irqrestore(&hw_data->lock, flags);
482 }
483
484 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
485 .kfree_skb_probe = trace_kfree_skb_hit,
486 .napi_poll_probe = trace_napi_poll_hit,
487 .work_item_func = send_dm_alert,
488 .hw_work_item_func = net_dm_hw_summary_work,
489 .hw_trap_probe = net_dm_hw_trap_summary_probe,
490 };
491
net_dm_packet_trace_kfree_skb_hit(void * ignore,struct sk_buff * skb,void * location,enum skb_drop_reason reason,struct sock * rx_sk)492 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
493 struct sk_buff *skb,
494 void *location,
495 enum skb_drop_reason reason,
496 struct sock *rx_sk)
497 {
498 ktime_t tstamp = ktime_get_real();
499 struct per_cpu_dm_data *data;
500 struct net_dm_skb_cb *cb;
501 struct sk_buff *nskb;
502 unsigned long flags;
503
504 if (!skb_mac_header_was_set(skb))
505 return;
506
507 nskb = skb_clone(skb, GFP_ATOMIC);
508 if (!nskb)
509 return;
510
511 cb = NET_DM_SKB_CB(nskb);
512 cb->reason = reason;
513 cb->pc = location;
514 /* Override the timestamp because we care about the time when the
515 * packet was dropped.
516 */
517 nskb->tstamp = tstamp;
518
519 data = this_cpu_ptr(&dm_cpu_data);
520
521 spin_lock_irqsave(&data->drop_queue.lock, flags);
522 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
523 __skb_queue_tail(&data->drop_queue, nskb);
524 else
525 goto unlock_free;
526 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
527
528 schedule_work(&data->dm_alert_work);
529
530 return;
531
532 unlock_free:
533 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
534 u64_stats_update_begin(&data->stats.syncp);
535 u64_stats_inc(&data->stats.dropped);
536 u64_stats_update_end(&data->stats.syncp);
537 consume_skb(nskb);
538 }
539
net_dm_packet_trace_napi_poll_hit(void * ignore,struct napi_struct * napi,int work,int budget)540 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
541 struct napi_struct *napi,
542 int work, int budget)
543 {
544 }
545
net_dm_in_port_size(void)546 static size_t net_dm_in_port_size(void)
547 {
548 /* NET_DM_ATTR_IN_PORT nest */
549 return nla_total_size(0) +
550 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
551 nla_total_size(sizeof(u32)) +
552 /* NET_DM_ATTR_PORT_NETDEV_NAME */
553 nla_total_size(IFNAMSIZ + 1);
554 }
555
556 #define NET_DM_MAX_SYMBOL_LEN 40
557 #define NET_DM_MAX_REASON_LEN 50
558
net_dm_packet_report_size(size_t payload_len)559 static size_t net_dm_packet_report_size(size_t payload_len)
560 {
561 size_t size;
562
563 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
564
565 return NLMSG_ALIGN(size) +
566 /* NET_DM_ATTR_ORIGIN */
567 nla_total_size(sizeof(u16)) +
568 /* NET_DM_ATTR_PC */
569 nla_total_size(sizeof(u64)) +
570 /* NET_DM_ATTR_SYMBOL */
571 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
572 /* NET_DM_ATTR_IN_PORT */
573 net_dm_in_port_size() +
574 /* NET_DM_ATTR_TIMESTAMP */
575 nla_total_size(sizeof(u64)) +
576 /* NET_DM_ATTR_ORIG_LEN */
577 nla_total_size(sizeof(u32)) +
578 /* NET_DM_ATTR_PROTO */
579 nla_total_size(sizeof(u16)) +
580 /* NET_DM_ATTR_REASON */
581 nla_total_size(NET_DM_MAX_REASON_LEN + 1) +
582 /* NET_DM_ATTR_PAYLOAD */
583 nla_total_size(payload_len);
584 }
585
net_dm_packet_report_in_port_put(struct sk_buff * msg,int ifindex,const char * name)586 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
587 const char *name)
588 {
589 struct nlattr *attr;
590
591 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
592 if (!attr)
593 return -EMSGSIZE;
594
595 if (ifindex &&
596 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
597 goto nla_put_failure;
598
599 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
600 goto nla_put_failure;
601
602 nla_nest_end(msg, attr);
603
604 return 0;
605
606 nla_put_failure:
607 nla_nest_cancel(msg, attr);
608 return -EMSGSIZE;
609 }
610
net_dm_packet_report_fill(struct sk_buff * msg,struct sk_buff * skb,size_t payload_len)611 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
612 size_t payload_len)
613 {
614 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
615 const struct drop_reason_list *list = NULL;
616 unsigned int subsys, subsys_reason;
617 char buf[NET_DM_MAX_SYMBOL_LEN];
618 struct nlattr *attr;
619 void *hdr;
620 int rc;
621
622 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
623 NET_DM_CMD_PACKET_ALERT);
624 if (!hdr)
625 return -EMSGSIZE;
626
627 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
628 goto nla_put_failure;
629
630 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc,
631 NET_DM_ATTR_PAD))
632 goto nla_put_failure;
633
634 rcu_read_lock();
635 subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK);
636 if (subsys < SKB_DROP_REASON_SUBSYS_NUM)
637 list = rcu_dereference(drop_reasons_by_subsys[subsys]);
638 subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK;
639 if (!list ||
640 subsys_reason >= list->n_reasons ||
641 !list->reasons[subsys_reason] ||
642 strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) {
643 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]);
644 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED;
645 }
646 if (nla_put_string(msg, NET_DM_ATTR_REASON,
647 list->reasons[subsys_reason])) {
648 rcu_read_unlock();
649 goto nla_put_failure;
650 }
651 rcu_read_unlock();
652
653 snprintf(buf, sizeof(buf), "%pS", cb->pc);
654 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
655 goto nla_put_failure;
656
657 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
658 if (rc)
659 goto nla_put_failure;
660
661 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
662 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
663 goto nla_put_failure;
664
665 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
666 goto nla_put_failure;
667
668 if (!payload_len)
669 goto out;
670
671 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
672 goto nla_put_failure;
673
674 attr = skb_put(msg, nla_total_size(payload_len));
675 attr->nla_type = NET_DM_ATTR_PAYLOAD;
676 attr->nla_len = nla_attr_size(payload_len);
677 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
678 goto nla_put_failure;
679
680 out:
681 genlmsg_end(msg, hdr);
682
683 return 0;
684
685 nla_put_failure:
686 genlmsg_cancel(msg, hdr);
687 return -EMSGSIZE;
688 }
689
690 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
691
net_dm_packet_report(struct sk_buff * skb)692 static void net_dm_packet_report(struct sk_buff *skb)
693 {
694 struct sk_buff *msg;
695 size_t payload_len;
696 int rc;
697
698 /* Make sure we start copying the packet from the MAC header */
699 if (skb->data > skb_mac_header(skb))
700 skb_push(skb, skb->data - skb_mac_header(skb));
701 else
702 skb_pull(skb, skb_mac_header(skb) - skb->data);
703
704 /* Ensure packet fits inside a single netlink attribute */
705 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
706 if (net_dm_trunc_len)
707 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
708
709 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
710 if (!msg)
711 goto out;
712
713 rc = net_dm_packet_report_fill(msg, skb, payload_len);
714 if (rc) {
715 nlmsg_free(msg);
716 goto out;
717 }
718
719 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
720
721 out:
722 consume_skb(skb);
723 }
724
net_dm_packet_work(struct work_struct * work)725 static void net_dm_packet_work(struct work_struct *work)
726 {
727 struct per_cpu_dm_data *data;
728 struct sk_buff_head list;
729 struct sk_buff *skb;
730 unsigned long flags;
731
732 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
733
734 __skb_queue_head_init(&list);
735
736 spin_lock_irqsave(&data->drop_queue.lock, flags);
737 skb_queue_splice_tail_init(&data->drop_queue, &list);
738 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
739
740 while ((skb = __skb_dequeue(&list)))
741 net_dm_packet_report(skb);
742 }
743
744 static size_t
net_dm_flow_action_cookie_size(const struct devlink_trap_metadata * hw_metadata)745 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
746 {
747 return hw_metadata->fa_cookie ?
748 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
749 }
750
751 static size_t
net_dm_hw_packet_report_size(size_t payload_len,const struct devlink_trap_metadata * hw_metadata)752 net_dm_hw_packet_report_size(size_t payload_len,
753 const struct devlink_trap_metadata *hw_metadata)
754 {
755 size_t size;
756
757 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
758
759 return NLMSG_ALIGN(size) +
760 /* NET_DM_ATTR_ORIGIN */
761 nla_total_size(sizeof(u16)) +
762 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
763 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
764 /* NET_DM_ATTR_HW_TRAP_NAME */
765 nla_total_size(strlen(hw_metadata->trap_name) + 1) +
766 /* NET_DM_ATTR_IN_PORT */
767 net_dm_in_port_size() +
768 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
769 net_dm_flow_action_cookie_size(hw_metadata) +
770 /* NET_DM_ATTR_TIMESTAMP */
771 nla_total_size(sizeof(u64)) +
772 /* NET_DM_ATTR_ORIG_LEN */
773 nla_total_size(sizeof(u32)) +
774 /* NET_DM_ATTR_PROTO */
775 nla_total_size(sizeof(u16)) +
776 /* NET_DM_ATTR_PAYLOAD */
777 nla_total_size(payload_len);
778 }
779
net_dm_hw_packet_report_fill(struct sk_buff * msg,struct sk_buff * skb,size_t payload_len)780 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
781 struct sk_buff *skb, size_t payload_len)
782 {
783 struct devlink_trap_metadata *hw_metadata;
784 struct nlattr *attr;
785 void *hdr;
786
787 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
788
789 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
790 NET_DM_CMD_PACKET_ALERT);
791 if (!hdr)
792 return -EMSGSIZE;
793
794 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
795 goto nla_put_failure;
796
797 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
798 hw_metadata->trap_group_name))
799 goto nla_put_failure;
800
801 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
802 hw_metadata->trap_name))
803 goto nla_put_failure;
804
805 if (hw_metadata->input_dev) {
806 struct net_device *dev = hw_metadata->input_dev;
807 int rc;
808
809 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
810 dev->name);
811 if (rc)
812 goto nla_put_failure;
813 }
814
815 if (hw_metadata->fa_cookie &&
816 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
817 hw_metadata->fa_cookie->cookie_len,
818 hw_metadata->fa_cookie->cookie))
819 goto nla_put_failure;
820
821 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
822 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
823 goto nla_put_failure;
824
825 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
826 goto nla_put_failure;
827
828 if (!payload_len)
829 goto out;
830
831 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
832 goto nla_put_failure;
833
834 attr = skb_put(msg, nla_total_size(payload_len));
835 attr->nla_type = NET_DM_ATTR_PAYLOAD;
836 attr->nla_len = nla_attr_size(payload_len);
837 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
838 goto nla_put_failure;
839
840 out:
841 genlmsg_end(msg, hdr);
842
843 return 0;
844
845 nla_put_failure:
846 genlmsg_cancel(msg, hdr);
847 return -EMSGSIZE;
848 }
849
850 static struct devlink_trap_metadata *
net_dm_hw_metadata_copy(const struct devlink_trap_metadata * metadata)851 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
852 {
853 const struct flow_action_cookie *fa_cookie;
854 struct devlink_trap_metadata *hw_metadata;
855 const char *trap_group_name;
856 const char *trap_name;
857
858 hw_metadata = kzalloc_obj(*hw_metadata, GFP_ATOMIC);
859 if (!hw_metadata)
860 return NULL;
861
862 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
863 if (!trap_group_name)
864 goto free_hw_metadata;
865 hw_metadata->trap_group_name = trap_group_name;
866
867 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
868 if (!trap_name)
869 goto free_trap_group;
870 hw_metadata->trap_name = trap_name;
871
872 if (metadata->fa_cookie) {
873 size_t cookie_size = sizeof(*fa_cookie) +
874 metadata->fa_cookie->cookie_len;
875
876 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
877 GFP_ATOMIC);
878 if (!fa_cookie)
879 goto free_trap_name;
880 hw_metadata->fa_cookie = fa_cookie;
881 }
882
883 hw_metadata->input_dev = metadata->input_dev;
884 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker,
885 GFP_ATOMIC);
886
887 return hw_metadata;
888
889 free_trap_name:
890 kfree(trap_name);
891 free_trap_group:
892 kfree(trap_group_name);
893 free_hw_metadata:
894 kfree(hw_metadata);
895 return NULL;
896 }
897
898 static void
net_dm_hw_metadata_free(struct devlink_trap_metadata * hw_metadata)899 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
900 {
901 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker);
902 kfree(hw_metadata->fa_cookie);
903 kfree(hw_metadata->trap_name);
904 kfree(hw_metadata->trap_group_name);
905 kfree(hw_metadata);
906 }
907
net_dm_hw_packet_report(struct sk_buff * skb)908 static void net_dm_hw_packet_report(struct sk_buff *skb)
909 {
910 struct devlink_trap_metadata *hw_metadata;
911 struct sk_buff *msg;
912 size_t payload_len;
913 int rc;
914
915 if (skb->data > skb_mac_header(skb))
916 skb_push(skb, skb->data - skb_mac_header(skb));
917 else
918 skb_pull(skb, skb_mac_header(skb) - skb->data);
919
920 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
921 if (net_dm_trunc_len)
922 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
923
924 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
925 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
926 GFP_KERNEL);
927 if (!msg)
928 goto out;
929
930 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
931 if (rc) {
932 nlmsg_free(msg);
933 goto out;
934 }
935
936 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
937
938 out:
939 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
940 consume_skb(skb);
941 }
942
net_dm_hw_packet_work(struct work_struct * work)943 static void net_dm_hw_packet_work(struct work_struct *work)
944 {
945 struct per_cpu_dm_data *hw_data;
946 struct sk_buff_head list;
947 struct sk_buff *skb;
948 unsigned long flags;
949
950 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
951
952 __skb_queue_head_init(&list);
953
954 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
955 skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
956 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
957
958 while ((skb = __skb_dequeue(&list)))
959 net_dm_hw_packet_report(skb);
960 }
961
962 static void
net_dm_hw_trap_packet_probe(void * ignore,const struct devlink * devlink,struct sk_buff * skb,const struct devlink_trap_metadata * metadata)963 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
964 struct sk_buff *skb,
965 const struct devlink_trap_metadata *metadata)
966 {
967 struct devlink_trap_metadata *n_hw_metadata;
968 ktime_t tstamp = ktime_get_real();
969 struct per_cpu_dm_data *hw_data;
970 struct sk_buff *nskb;
971 unsigned long flags;
972
973 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
974 return;
975
976 if (!skb_mac_header_was_set(skb))
977 return;
978
979 nskb = skb_clone(skb, GFP_ATOMIC);
980 if (!nskb)
981 return;
982
983 n_hw_metadata = net_dm_hw_metadata_copy(metadata);
984 if (!n_hw_metadata)
985 goto free;
986
987 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
988 nskb->tstamp = tstamp;
989
990 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
991
992 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
993 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
994 __skb_queue_tail(&hw_data->drop_queue, nskb);
995 else
996 goto unlock_free;
997 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
998
999 schedule_work(&hw_data->dm_alert_work);
1000
1001 return;
1002
1003 unlock_free:
1004 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
1005 u64_stats_update_begin(&hw_data->stats.syncp);
1006 u64_stats_inc(&hw_data->stats.dropped);
1007 u64_stats_update_end(&hw_data->stats.syncp);
1008 net_dm_hw_metadata_free(n_hw_metadata);
1009 free:
1010 consume_skb(nskb);
1011 }
1012
1013 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
1014 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
1015 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
1016 .work_item_func = net_dm_packet_work,
1017 .hw_work_item_func = net_dm_hw_packet_work,
1018 .hw_trap_probe = net_dm_hw_trap_packet_probe,
1019 };
1020
1021 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1022 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
1023 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
1024 };
1025
1026 #if IS_ENABLED(CONFIG_NET_DEVLINK)
net_dm_hw_probe_register(const struct net_dm_alert_ops * ops)1027 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1028 {
1029 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1030 }
1031
net_dm_hw_probe_unregister(const struct net_dm_alert_ops * ops)1032 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1033 {
1034 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1035 tracepoint_synchronize_unregister();
1036 }
1037 #else
net_dm_hw_probe_register(const struct net_dm_alert_ops * ops)1038 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1039 {
1040 return -EOPNOTSUPP;
1041 }
1042
net_dm_hw_probe_unregister(const struct net_dm_alert_ops * ops)1043 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1044 {
1045 }
1046 #endif
1047
net_dm_hw_monitor_start(struct netlink_ext_ack * extack)1048 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1049 {
1050 const struct net_dm_alert_ops *ops;
1051 int cpu, rc;
1052
1053 if (monitor_hw) {
1054 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1055 return -EAGAIN;
1056 }
1057
1058 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1059
1060 if (!try_module_get(THIS_MODULE)) {
1061 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1062 return -ENODEV;
1063 }
1064
1065 for_each_possible_cpu(cpu) {
1066 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1067 struct net_dm_hw_entries *hw_entries;
1068
1069 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1070 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1071 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1072 kfree(hw_entries);
1073 }
1074
1075 rc = net_dm_hw_probe_register(ops);
1076 if (rc) {
1077 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1078 goto err_module_put;
1079 }
1080
1081 monitor_hw = true;
1082
1083 return 0;
1084
1085 err_module_put:
1086 for_each_possible_cpu(cpu) {
1087 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1088 struct sk_buff *skb;
1089
1090 timer_delete_sync(&hw_data->send_timer);
1091 cancel_work_sync(&hw_data->dm_alert_work);
1092 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1093 struct devlink_trap_metadata *hw_metadata;
1094
1095 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1096 net_dm_hw_metadata_free(hw_metadata);
1097 consume_skb(skb);
1098 }
1099 }
1100 module_put(THIS_MODULE);
1101 return rc;
1102 }
1103
net_dm_hw_monitor_stop(struct netlink_ext_ack * extack)1104 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1105 {
1106 const struct net_dm_alert_ops *ops;
1107 int cpu;
1108
1109 if (!monitor_hw) {
1110 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1111 return;
1112 }
1113
1114 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1115
1116 monitor_hw = false;
1117
1118 net_dm_hw_probe_unregister(ops);
1119
1120 for_each_possible_cpu(cpu) {
1121 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1122 struct sk_buff *skb;
1123
1124 timer_delete_sync(&hw_data->send_timer);
1125 cancel_work_sync(&hw_data->dm_alert_work);
1126 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1127 struct devlink_trap_metadata *hw_metadata;
1128
1129 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1130 net_dm_hw_metadata_free(hw_metadata);
1131 consume_skb(skb);
1132 }
1133 }
1134
1135 module_put(THIS_MODULE);
1136 }
1137
net_dm_trace_on_set(struct netlink_ext_ack * extack)1138 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1139 {
1140 const struct net_dm_alert_ops *ops;
1141 int cpu, rc;
1142
1143 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1144
1145 if (!try_module_get(THIS_MODULE)) {
1146 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1147 return -ENODEV;
1148 }
1149
1150 for_each_possible_cpu(cpu) {
1151 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1152 struct sk_buff *skb;
1153
1154 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1155 timer_setup(&data->send_timer, sched_send_work, 0);
1156 /* Allocate a new per-CPU skb for the summary alert message and
1157 * free the old one which might contain stale data from
1158 * previous tracing.
1159 */
1160 skb = reset_per_cpu_data(data);
1161 consume_skb(skb);
1162 }
1163
1164 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1165 if (rc) {
1166 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1167 goto err_module_put;
1168 }
1169
1170 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1171 if (rc) {
1172 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1173 goto err_unregister_trace;
1174 }
1175
1176 return 0;
1177
1178 err_unregister_trace:
1179 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1180 err_module_put:
1181 for_each_possible_cpu(cpu) {
1182 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1183 struct sk_buff *skb;
1184
1185 timer_delete_sync(&data->send_timer);
1186 cancel_work_sync(&data->dm_alert_work);
1187 while ((skb = __skb_dequeue(&data->drop_queue)))
1188 consume_skb(skb);
1189 }
1190 module_put(THIS_MODULE);
1191 return rc;
1192 }
1193
net_dm_trace_off_set(void)1194 static void net_dm_trace_off_set(void)
1195 {
1196 const struct net_dm_alert_ops *ops;
1197 int cpu;
1198
1199 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1200
1201 unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1202 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1203
1204 tracepoint_synchronize_unregister();
1205
1206 /* Make sure we do not send notifications to user space after request
1207 * to stop tracing returns.
1208 */
1209 for_each_possible_cpu(cpu) {
1210 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1211 struct sk_buff *skb;
1212
1213 timer_delete_sync(&data->send_timer);
1214 cancel_work_sync(&data->dm_alert_work);
1215 while ((skb = __skb_dequeue(&data->drop_queue)))
1216 consume_skb(skb);
1217 }
1218
1219 module_put(THIS_MODULE);
1220 }
1221
set_all_monitor_traces(int state,struct netlink_ext_ack * extack)1222 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1223 {
1224 int rc = 0;
1225
1226 if (state == trace_state) {
1227 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1228 return -EAGAIN;
1229 }
1230
1231 switch (state) {
1232 case TRACE_ON:
1233 rc = net_dm_trace_on_set(extack);
1234 break;
1235 case TRACE_OFF:
1236 net_dm_trace_off_set();
1237 break;
1238 default:
1239 rc = 1;
1240 break;
1241 }
1242
1243 if (!rc)
1244 trace_state = state;
1245 else
1246 rc = -EINPROGRESS;
1247
1248 return rc;
1249 }
1250
net_dm_is_monitoring(void)1251 static bool net_dm_is_monitoring(void)
1252 {
1253 return trace_state == TRACE_ON || monitor_hw;
1254 }
1255
net_dm_alert_mode_get_from_info(struct genl_info * info,enum net_dm_alert_mode * p_alert_mode)1256 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1257 enum net_dm_alert_mode *p_alert_mode)
1258 {
1259 u8 val;
1260
1261 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1262
1263 switch (val) {
1264 case NET_DM_ALERT_MODE_SUMMARY:
1265 case NET_DM_ALERT_MODE_PACKET:
1266 *p_alert_mode = val;
1267 break;
1268 default:
1269 return -EINVAL;
1270 }
1271
1272 return 0;
1273 }
1274
net_dm_alert_mode_set(struct genl_info * info)1275 static int net_dm_alert_mode_set(struct genl_info *info)
1276 {
1277 struct netlink_ext_ack *extack = info->extack;
1278 enum net_dm_alert_mode alert_mode;
1279 int rc;
1280
1281 if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1282 return 0;
1283
1284 rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1285 if (rc) {
1286 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1287 return -EINVAL;
1288 }
1289
1290 net_dm_alert_mode = alert_mode;
1291
1292 return 0;
1293 }
1294
net_dm_trunc_len_set(struct genl_info * info)1295 static void net_dm_trunc_len_set(struct genl_info *info)
1296 {
1297 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1298 return;
1299
1300 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1301 }
1302
net_dm_queue_len_set(struct genl_info * info)1303 static void net_dm_queue_len_set(struct genl_info *info)
1304 {
1305 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1306 return;
1307
1308 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1309 }
1310
net_dm_cmd_config(struct sk_buff * skb,struct genl_info * info)1311 static int net_dm_cmd_config(struct sk_buff *skb,
1312 struct genl_info *info)
1313 {
1314 struct netlink_ext_ack *extack = info->extack;
1315 int rc;
1316
1317 if (net_dm_is_monitoring()) {
1318 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1319 return -EBUSY;
1320 }
1321
1322 rc = net_dm_alert_mode_set(info);
1323 if (rc)
1324 return rc;
1325
1326 net_dm_trunc_len_set(info);
1327
1328 net_dm_queue_len_set(info);
1329
1330 return 0;
1331 }
1332
net_dm_monitor_start(bool set_sw,bool set_hw,struct netlink_ext_ack * extack)1333 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1334 struct netlink_ext_ack *extack)
1335 {
1336 bool sw_set = false;
1337 int rc;
1338
1339 if (set_sw) {
1340 rc = set_all_monitor_traces(TRACE_ON, extack);
1341 if (rc)
1342 return rc;
1343 sw_set = true;
1344 }
1345
1346 if (set_hw) {
1347 rc = net_dm_hw_monitor_start(extack);
1348 if (rc)
1349 goto err_monitor_hw;
1350 }
1351
1352 return 0;
1353
1354 err_monitor_hw:
1355 if (sw_set)
1356 set_all_monitor_traces(TRACE_OFF, extack);
1357 return rc;
1358 }
1359
net_dm_monitor_stop(bool set_sw,bool set_hw,struct netlink_ext_ack * extack)1360 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1361 struct netlink_ext_ack *extack)
1362 {
1363 if (set_hw)
1364 net_dm_hw_monitor_stop(extack);
1365 if (set_sw)
1366 set_all_monitor_traces(TRACE_OFF, extack);
1367 }
1368
net_dm_cmd_trace(struct sk_buff * skb,struct genl_info * info)1369 static int net_dm_cmd_trace(struct sk_buff *skb,
1370 struct genl_info *info)
1371 {
1372 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1373 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1374 struct netlink_ext_ack *extack = info->extack;
1375
1376 /* To maintain backward compatibility, we start / stop monitoring of
1377 * software drops if no flag is specified.
1378 */
1379 if (!set_sw && !set_hw)
1380 set_sw = true;
1381
1382 switch (info->genlhdr->cmd) {
1383 case NET_DM_CMD_START:
1384 return net_dm_monitor_start(set_sw, set_hw, extack);
1385 case NET_DM_CMD_STOP:
1386 net_dm_monitor_stop(set_sw, set_hw, extack);
1387 return 0;
1388 }
1389
1390 return -EOPNOTSUPP;
1391 }
1392
net_dm_config_fill(struct sk_buff * msg,struct genl_info * info)1393 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1394 {
1395 void *hdr;
1396
1397 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1398 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1399 if (!hdr)
1400 return -EMSGSIZE;
1401
1402 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1403 goto nla_put_failure;
1404
1405 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1406 goto nla_put_failure;
1407
1408 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1409 goto nla_put_failure;
1410
1411 genlmsg_end(msg, hdr);
1412
1413 return 0;
1414
1415 nla_put_failure:
1416 genlmsg_cancel(msg, hdr);
1417 return -EMSGSIZE;
1418 }
1419
net_dm_cmd_config_get(struct sk_buff * skb,struct genl_info * info)1420 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1421 {
1422 struct sk_buff *msg;
1423 int rc;
1424
1425 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1426 if (!msg)
1427 return -ENOMEM;
1428
1429 rc = net_dm_config_fill(msg, info);
1430 if (rc)
1431 goto free_msg;
1432
1433 return genlmsg_reply(msg, info);
1434
1435 free_msg:
1436 nlmsg_free(msg);
1437 return rc;
1438 }
1439
net_dm_stats_read(struct net_dm_stats * stats)1440 static void net_dm_stats_read(struct net_dm_stats *stats)
1441 {
1442 int cpu;
1443
1444 memset(stats, 0, sizeof(*stats));
1445 for_each_possible_cpu(cpu) {
1446 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1447 struct net_dm_stats *cpu_stats = &data->stats;
1448 unsigned int start;
1449 u64 dropped;
1450
1451 do {
1452 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1453 dropped = u64_stats_read(&cpu_stats->dropped);
1454 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1455
1456 u64_stats_add(&stats->dropped, dropped);
1457 }
1458 }
1459
net_dm_stats_put(struct sk_buff * msg)1460 static int net_dm_stats_put(struct sk_buff *msg)
1461 {
1462 struct net_dm_stats stats;
1463 struct nlattr *attr;
1464
1465 net_dm_stats_read(&stats);
1466
1467 attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1468 if (!attr)
1469 return -EMSGSIZE;
1470
1471 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1472 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1473 goto nla_put_failure;
1474
1475 nla_nest_end(msg, attr);
1476
1477 return 0;
1478
1479 nla_put_failure:
1480 nla_nest_cancel(msg, attr);
1481 return -EMSGSIZE;
1482 }
1483
net_dm_hw_stats_read(struct net_dm_stats * stats)1484 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1485 {
1486 int cpu;
1487
1488 memset(stats, 0, sizeof(*stats));
1489 for_each_possible_cpu(cpu) {
1490 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1491 struct net_dm_stats *cpu_stats = &hw_data->stats;
1492 unsigned int start;
1493 u64 dropped;
1494
1495 do {
1496 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1497 dropped = u64_stats_read(&cpu_stats->dropped);
1498 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1499
1500 u64_stats_add(&stats->dropped, dropped);
1501 }
1502 }
1503
net_dm_hw_stats_put(struct sk_buff * msg)1504 static int net_dm_hw_stats_put(struct sk_buff *msg)
1505 {
1506 struct net_dm_stats stats;
1507 struct nlattr *attr;
1508
1509 net_dm_hw_stats_read(&stats);
1510
1511 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1512 if (!attr)
1513 return -EMSGSIZE;
1514
1515 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1516 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1517 goto nla_put_failure;
1518
1519 nla_nest_end(msg, attr);
1520
1521 return 0;
1522
1523 nla_put_failure:
1524 nla_nest_cancel(msg, attr);
1525 return -EMSGSIZE;
1526 }
1527
net_dm_stats_fill(struct sk_buff * msg,struct genl_info * info)1528 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1529 {
1530 void *hdr;
1531 int rc;
1532
1533 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1534 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1535 if (!hdr)
1536 return -EMSGSIZE;
1537
1538 rc = net_dm_stats_put(msg);
1539 if (rc)
1540 goto nla_put_failure;
1541
1542 rc = net_dm_hw_stats_put(msg);
1543 if (rc)
1544 goto nla_put_failure;
1545
1546 genlmsg_end(msg, hdr);
1547
1548 return 0;
1549
1550 nla_put_failure:
1551 genlmsg_cancel(msg, hdr);
1552 return -EMSGSIZE;
1553 }
1554
net_dm_cmd_stats_get(struct sk_buff * skb,struct genl_info * info)1555 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1556 {
1557 struct sk_buff *msg;
1558 int rc;
1559
1560 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1561 if (!msg)
1562 return -ENOMEM;
1563
1564 rc = net_dm_stats_fill(msg, info);
1565 if (rc)
1566 goto free_msg;
1567
1568 return genlmsg_reply(msg, info);
1569
1570 free_msg:
1571 nlmsg_free(msg);
1572 return rc;
1573 }
1574
dropmon_net_event(struct notifier_block * ev_block,unsigned long event,void * ptr)1575 static int dropmon_net_event(struct notifier_block *ev_block,
1576 unsigned long event, void *ptr)
1577 {
1578 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1579 struct dm_hw_stat_delta *stat;
1580
1581 switch (event) {
1582 case NETDEV_REGISTER:
1583 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1584 break;
1585 stat = kzalloc_obj(*stat);
1586 if (!stat)
1587 break;
1588
1589 stat->last_rx = jiffies;
1590 rcu_assign_pointer(dev->dm_private, stat);
1591
1592 break;
1593 case NETDEV_UNREGISTER:
1594 stat = rtnl_dereference(dev->dm_private);
1595 if (stat) {
1596 rcu_assign_pointer(dev->dm_private, NULL);
1597 kfree_rcu(stat, rcu);
1598 }
1599 break;
1600 }
1601 return NOTIFY_DONE;
1602 }
1603
1604 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1605 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1606 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1607 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1608 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1609 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG },
1610 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG },
1611 };
1612
1613 static const struct genl_small_ops dropmon_ops[] = {
1614 {
1615 .cmd = NET_DM_CMD_CONFIG,
1616 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1617 .doit = net_dm_cmd_config,
1618 .flags = GENL_ADMIN_PERM,
1619 },
1620 {
1621 .cmd = NET_DM_CMD_START,
1622 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1623 .doit = net_dm_cmd_trace,
1624 .flags = GENL_ADMIN_PERM,
1625 },
1626 {
1627 .cmd = NET_DM_CMD_STOP,
1628 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1629 .doit = net_dm_cmd_trace,
1630 .flags = GENL_ADMIN_PERM,
1631 },
1632 {
1633 .cmd = NET_DM_CMD_CONFIG_GET,
1634 .doit = net_dm_cmd_config_get,
1635 },
1636 {
1637 .cmd = NET_DM_CMD_STATS_GET,
1638 .doit = net_dm_cmd_stats_get,
1639 },
1640 };
1641
net_dm_nl_pre_doit(const struct genl_split_ops * ops,struct sk_buff * skb,struct genl_info * info)1642 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
1643 struct sk_buff *skb, struct genl_info *info)
1644 {
1645 mutex_lock(&net_dm_mutex);
1646
1647 return 0;
1648 }
1649
net_dm_nl_post_doit(const struct genl_split_ops * ops,struct sk_buff * skb,struct genl_info * info)1650 static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
1651 struct sk_buff *skb, struct genl_info *info)
1652 {
1653 mutex_unlock(&net_dm_mutex);
1654 }
1655
1656 static struct genl_family net_drop_monitor_family __ro_after_init = {
1657 .hdrsize = 0,
1658 .name = "NET_DM",
1659 .version = 2,
1660 .maxattr = NET_DM_ATTR_MAX,
1661 .policy = net_dm_nl_policy,
1662 .pre_doit = net_dm_nl_pre_doit,
1663 .post_doit = net_dm_nl_post_doit,
1664 .module = THIS_MODULE,
1665 .small_ops = dropmon_ops,
1666 .n_small_ops = ARRAY_SIZE(dropmon_ops),
1667 .resv_start_op = NET_DM_CMD_STATS_GET + 1,
1668 .mcgrps = dropmon_mcgrps,
1669 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps),
1670 };
1671
1672 static struct notifier_block dropmon_net_notifier = {
1673 .notifier_call = dropmon_net_event
1674 };
1675
__net_dm_cpu_data_init(struct per_cpu_dm_data * data)1676 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1677 {
1678 raw_spin_lock_init(&data->lock);
1679 skb_queue_head_init(&data->drop_queue);
1680 u64_stats_init(&data->stats.syncp);
1681 }
1682
__net_dm_cpu_data_fini(struct per_cpu_dm_data * data)1683 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1684 {
1685 WARN_ON(!skb_queue_empty(&data->drop_queue));
1686 }
1687
net_dm_cpu_data_init(int cpu)1688 static void net_dm_cpu_data_init(int cpu)
1689 {
1690 struct per_cpu_dm_data *data;
1691
1692 data = &per_cpu(dm_cpu_data, cpu);
1693 __net_dm_cpu_data_init(data);
1694 }
1695
net_dm_cpu_data_fini(int cpu)1696 static void net_dm_cpu_data_fini(int cpu)
1697 {
1698 struct per_cpu_dm_data *data;
1699
1700 data = &per_cpu(dm_cpu_data, cpu);
1701 /* At this point, we should have exclusive access
1702 * to this struct and can free the skb inside it.
1703 */
1704 consume_skb(data->skb);
1705 __net_dm_cpu_data_fini(data);
1706 }
1707
net_dm_hw_cpu_data_init(int cpu)1708 static void net_dm_hw_cpu_data_init(int cpu)
1709 {
1710 struct per_cpu_dm_data *hw_data;
1711
1712 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1713 __net_dm_cpu_data_init(hw_data);
1714 }
1715
net_dm_hw_cpu_data_fini(int cpu)1716 static void net_dm_hw_cpu_data_fini(int cpu)
1717 {
1718 struct per_cpu_dm_data *hw_data;
1719
1720 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1721 kfree(hw_data->hw_entries);
1722 __net_dm_cpu_data_fini(hw_data);
1723 }
1724
init_net_drop_monitor(void)1725 static int __init init_net_drop_monitor(void)
1726 {
1727 int cpu, rc;
1728
1729 pr_info("Initializing network drop monitor service\n");
1730
1731 if (sizeof(void *) > 8) {
1732 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1733 return -ENOSPC;
1734 }
1735
1736 for_each_possible_cpu(cpu) {
1737 net_dm_cpu_data_init(cpu);
1738 net_dm_hw_cpu_data_init(cpu);
1739 }
1740
1741 rc = register_netdevice_notifier(&dropmon_net_notifier);
1742 if (rc < 0) {
1743 pr_crit("Failed to register netdevice notifier\n");
1744 return rc;
1745 }
1746
1747 rc = genl_register_family(&net_drop_monitor_family);
1748 if (rc) {
1749 pr_err("Could not create drop monitor netlink family\n");
1750 goto out_unreg;
1751 }
1752 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1753
1754 rc = 0;
1755
1756 goto out;
1757
1758 out_unreg:
1759 WARN_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1760 out:
1761 return rc;
1762 }
1763
exit_net_drop_monitor(void)1764 static void exit_net_drop_monitor(void)
1765 {
1766 int cpu;
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 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1773
1774 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1775
1776 for_each_possible_cpu(cpu) {
1777 net_dm_hw_cpu_data_fini(cpu);
1778 net_dm_cpu_data_fini(cpu);
1779 }
1780 }
1781
1782 module_init(init_net_drop_monitor);
1783 module_exit(exit_net_drop_monitor);
1784
1785 MODULE_LICENSE("GPL v2");
1786 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1787 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1788 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");
1789