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 const 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,const 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 const 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,const 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 const 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 u64_stats_update_begin(&data->stats.syncp);
534 u64_stats_inc(&data->stats.dropped);
535 u64_stats_update_end(&data->stats.syncp);
536 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
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_64bit(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_64bit(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 = __nla_reserve(msg, NET_DM_ATTR_PAYLOAD, payload_len);
675 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
676 goto nla_put_failure;
677
678 out:
679 genlmsg_end(msg, hdr);
680
681 return 0;
682
683 nla_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
net_dm_packet_report(struct sk_buff * skb)690 static 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
719 out:
720 consume_skb(skb);
721 }
722
net_dm_packet_work(struct work_struct * work)723 static 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
742 static size_t
net_dm_flow_action_cookie_size(const struct devlink_trap_metadata * hw_metadata)743 net_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
749 static size_t
net_dm_hw_packet_report_size(size_t payload_len,const struct devlink_trap_metadata * hw_metadata)750 net_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_64bit(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
net_dm_hw_packet_report_fill(struct sk_buff * msg,struct sk_buff * skb,size_t payload_len)778 static 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 = __nla_reserve(msg, NET_DM_ATTR_PAYLOAD, payload_len);
833 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
834 goto nla_put_failure;
835
836 out:
837 genlmsg_end(msg, hdr);
838
839 return 0;
840
841 nla_put_failure:
842 genlmsg_cancel(msg, hdr);
843 return -EMSGSIZE;
844 }
845
846 static struct devlink_trap_metadata *
net_dm_hw_metadata_copy(const struct devlink_trap_metadata * metadata)847 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
848 {
849 const struct flow_action_cookie *fa_cookie;
850 struct devlink_trap_metadata *hw_metadata;
851 const char *trap_group_name;
852 const char *trap_name;
853
854 hw_metadata = kzalloc_obj(*hw_metadata, GFP_ATOMIC);
855 if (!hw_metadata)
856 return NULL;
857
858 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
859 if (!trap_group_name)
860 goto free_hw_metadata;
861 hw_metadata->trap_group_name = trap_group_name;
862
863 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
864 if (!trap_name)
865 goto free_trap_group;
866 hw_metadata->trap_name = trap_name;
867
868 if (metadata->fa_cookie) {
869 size_t cookie_size = sizeof(*fa_cookie) +
870 metadata->fa_cookie->cookie_len;
871
872 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
873 GFP_ATOMIC);
874 if (!fa_cookie)
875 goto free_trap_name;
876 hw_metadata->fa_cookie = fa_cookie;
877 }
878
879 hw_metadata->input_dev = metadata->input_dev;
880 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker,
881 GFP_ATOMIC);
882
883 return hw_metadata;
884
885 free_trap_name:
886 kfree(trap_name);
887 free_trap_group:
888 kfree(trap_group_name);
889 free_hw_metadata:
890 kfree(hw_metadata);
891 return NULL;
892 }
893
894 static void
net_dm_hw_metadata_free(struct devlink_trap_metadata * hw_metadata)895 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
896 {
897 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker);
898 kfree(hw_metadata->fa_cookie);
899 kfree(hw_metadata->trap_name);
900 kfree(hw_metadata->trap_group_name);
901 kfree(hw_metadata);
902 }
903
net_dm_hw_packet_report(struct sk_buff * skb)904 static void net_dm_hw_packet_report(struct sk_buff *skb)
905 {
906 struct devlink_trap_metadata *hw_metadata;
907 struct sk_buff *msg;
908 size_t payload_len;
909 int rc;
910
911 if (skb->data > skb_mac_header(skb))
912 skb_push(skb, skb->data - skb_mac_header(skb));
913 else
914 skb_pull(skb, skb_mac_header(skb) - skb->data);
915
916 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
917 if (net_dm_trunc_len)
918 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
919
920 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
921 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
922 GFP_KERNEL);
923 if (!msg)
924 goto out;
925
926 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
927 if (rc) {
928 nlmsg_free(msg);
929 goto out;
930 }
931
932 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
933
934 out:
935 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
936 consume_skb(skb);
937 }
938
net_dm_hw_packet_work(struct work_struct * work)939 static void net_dm_hw_packet_work(struct work_struct *work)
940 {
941 struct per_cpu_dm_data *hw_data;
942 struct sk_buff_head list;
943 struct sk_buff *skb;
944 unsigned long flags;
945
946 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
947
948 __skb_queue_head_init(&list);
949
950 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
951 skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
952 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
953
954 while ((skb = __skb_dequeue(&list)))
955 net_dm_hw_packet_report(skb);
956 }
957
958 static void
net_dm_hw_trap_packet_probe(void * ignore,const struct devlink * devlink,struct sk_buff * skb,const struct devlink_trap_metadata * metadata)959 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
960 struct sk_buff *skb,
961 const struct devlink_trap_metadata *metadata)
962 {
963 struct devlink_trap_metadata *n_hw_metadata;
964 ktime_t tstamp = ktime_get_real();
965 struct per_cpu_dm_data *hw_data;
966 struct sk_buff *nskb;
967 unsigned long flags;
968
969 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
970 return;
971
972 if (!skb_mac_header_was_set(skb))
973 return;
974
975 nskb = skb_clone(skb, GFP_ATOMIC);
976 if (!nskb)
977 return;
978
979 n_hw_metadata = net_dm_hw_metadata_copy(metadata);
980 if (!n_hw_metadata)
981 goto free;
982
983 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
984 nskb->tstamp = tstamp;
985
986 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
987
988 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
989 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
990 __skb_queue_tail(&hw_data->drop_queue, nskb);
991 else
992 goto unlock_free;
993 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
994
995 schedule_work(&hw_data->dm_alert_work);
996
997 return;
998
999 unlock_free:
1000 u64_stats_update_begin(&hw_data->stats.syncp);
1001 u64_stats_inc(&hw_data->stats.dropped);
1002 u64_stats_update_end(&hw_data->stats.syncp);
1003 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
1004 net_dm_hw_metadata_free(n_hw_metadata);
1005 free:
1006 consume_skb(nskb);
1007 }
1008
1009 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
1010 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
1011 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
1012 .work_item_func = net_dm_packet_work,
1013 .hw_work_item_func = net_dm_hw_packet_work,
1014 .hw_trap_probe = net_dm_hw_trap_packet_probe,
1015 };
1016
1017 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1018 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
1019 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
1020 };
1021
1022 #if IS_ENABLED(CONFIG_NET_DEVLINK)
net_dm_hw_probe_register(const struct net_dm_alert_ops * ops)1023 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1024 {
1025 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1026 }
1027
net_dm_hw_probe_unregister(const struct net_dm_alert_ops * ops)1028 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1029 {
1030 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1031 tracepoint_synchronize_unregister();
1032 }
1033 #else
net_dm_hw_probe_register(const struct net_dm_alert_ops * ops)1034 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1035 {
1036 return -EOPNOTSUPP;
1037 }
1038
net_dm_hw_probe_unregister(const struct net_dm_alert_ops * ops)1039 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1040 {
1041 }
1042 #endif
1043
net_dm_hw_monitor_start(struct netlink_ext_ack * extack)1044 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1045 {
1046 const struct net_dm_alert_ops *ops;
1047 int cpu, rc;
1048
1049 if (monitor_hw) {
1050 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1051 return -EAGAIN;
1052 }
1053
1054 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1055
1056 if (!try_module_get(THIS_MODULE)) {
1057 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1058 return -ENODEV;
1059 }
1060
1061 for_each_possible_cpu(cpu) {
1062 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1063 struct net_dm_hw_entries *hw_entries;
1064
1065 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1066 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1067 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1068 kfree(hw_entries);
1069 }
1070
1071 rc = net_dm_hw_probe_register(ops);
1072 if (rc) {
1073 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1074 goto err_module_put;
1075 }
1076
1077 monitor_hw = true;
1078
1079 return 0;
1080
1081 err_module_put:
1082 for_each_possible_cpu(cpu) {
1083 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1084 struct sk_buff *skb;
1085
1086 timer_delete_sync(&hw_data->send_timer);
1087 cancel_work_sync(&hw_data->dm_alert_work);
1088 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1089 struct devlink_trap_metadata *hw_metadata;
1090
1091 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1092 net_dm_hw_metadata_free(hw_metadata);
1093 consume_skb(skb);
1094 }
1095 }
1096 module_put(THIS_MODULE);
1097 return rc;
1098 }
1099
net_dm_hw_monitor_stop(struct netlink_ext_ack * extack)1100 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1101 {
1102 const struct net_dm_alert_ops *ops;
1103 int cpu;
1104
1105 if (!monitor_hw) {
1106 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1107 return;
1108 }
1109
1110 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1111
1112 monitor_hw = false;
1113
1114 net_dm_hw_probe_unregister(ops);
1115
1116 for_each_possible_cpu(cpu) {
1117 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1118 struct sk_buff *skb;
1119
1120 timer_delete_sync(&hw_data->send_timer);
1121 cancel_work_sync(&hw_data->dm_alert_work);
1122 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1123 struct devlink_trap_metadata *hw_metadata;
1124
1125 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1126 net_dm_hw_metadata_free(hw_metadata);
1127 consume_skb(skb);
1128 }
1129 }
1130
1131 module_put(THIS_MODULE);
1132 }
1133
net_dm_trace_on_set(struct netlink_ext_ack * extack)1134 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1135 {
1136 const struct net_dm_alert_ops *ops;
1137 int cpu, rc;
1138
1139 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1140
1141 if (!try_module_get(THIS_MODULE)) {
1142 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1143 return -ENODEV;
1144 }
1145
1146 for_each_possible_cpu(cpu) {
1147 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1148 struct sk_buff *skb;
1149
1150 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1151 timer_setup(&data->send_timer, sched_send_work, 0);
1152 /* Allocate a new per-CPU skb for the summary alert message and
1153 * free the old one which might contain stale data from
1154 * previous tracing.
1155 */
1156 skb = reset_per_cpu_data(data);
1157 consume_skb(skb);
1158 }
1159
1160 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1161 if (rc) {
1162 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1163 goto err_module_put;
1164 }
1165
1166 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1167 if (rc) {
1168 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1169 goto err_unregister_trace;
1170 }
1171
1172 return 0;
1173
1174 err_unregister_trace:
1175 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1176 err_module_put:
1177 for_each_possible_cpu(cpu) {
1178 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1179 struct sk_buff *skb;
1180
1181 timer_delete_sync(&data->send_timer);
1182 cancel_work_sync(&data->dm_alert_work);
1183 while ((skb = __skb_dequeue(&data->drop_queue)))
1184 consume_skb(skb);
1185 }
1186 module_put(THIS_MODULE);
1187 return rc;
1188 }
1189
net_dm_trace_off_set(void)1190 static void net_dm_trace_off_set(void)
1191 {
1192 const struct net_dm_alert_ops *ops;
1193 int cpu;
1194
1195 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1196
1197 unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1198 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1199
1200 tracepoint_synchronize_unregister();
1201
1202 /* Make sure we do not send notifications to user space after request
1203 * to stop tracing returns.
1204 */
1205 for_each_possible_cpu(cpu) {
1206 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1207 struct sk_buff *skb;
1208
1209 timer_delete_sync(&data->send_timer);
1210 cancel_work_sync(&data->dm_alert_work);
1211 while ((skb = __skb_dequeue(&data->drop_queue)))
1212 consume_skb(skb);
1213 }
1214
1215 module_put(THIS_MODULE);
1216 }
1217
set_all_monitor_traces(int state,struct netlink_ext_ack * extack)1218 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1219 {
1220 int rc = 0;
1221
1222 if (state == trace_state) {
1223 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1224 return -EAGAIN;
1225 }
1226
1227 switch (state) {
1228 case TRACE_ON:
1229 rc = net_dm_trace_on_set(extack);
1230 break;
1231 case TRACE_OFF:
1232 net_dm_trace_off_set();
1233 break;
1234 default:
1235 rc = 1;
1236 break;
1237 }
1238
1239 if (!rc)
1240 trace_state = state;
1241 else
1242 rc = -EINPROGRESS;
1243
1244 return rc;
1245 }
1246
net_dm_is_monitoring(void)1247 static bool net_dm_is_monitoring(void)
1248 {
1249 return trace_state == TRACE_ON || monitor_hw;
1250 }
1251
net_dm_alert_mode_get_from_info(struct genl_info * info,enum net_dm_alert_mode * p_alert_mode)1252 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1253 enum net_dm_alert_mode *p_alert_mode)
1254 {
1255 u8 val;
1256
1257 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1258
1259 switch (val) {
1260 case NET_DM_ALERT_MODE_SUMMARY:
1261 case NET_DM_ALERT_MODE_PACKET:
1262 *p_alert_mode = val;
1263 break;
1264 default:
1265 return -EINVAL;
1266 }
1267
1268 return 0;
1269 }
1270
net_dm_alert_mode_set(struct genl_info * info)1271 static int net_dm_alert_mode_set(struct genl_info *info)
1272 {
1273 struct netlink_ext_ack *extack = info->extack;
1274 enum net_dm_alert_mode alert_mode;
1275 int rc;
1276
1277 if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1278 return 0;
1279
1280 rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1281 if (rc) {
1282 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1283 return -EINVAL;
1284 }
1285
1286 net_dm_alert_mode = alert_mode;
1287
1288 return 0;
1289 }
1290
net_dm_trunc_len_set(struct genl_info * info)1291 static void net_dm_trunc_len_set(struct genl_info *info)
1292 {
1293 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1294 return;
1295
1296 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1297 }
1298
net_dm_queue_len_set(struct genl_info * info)1299 static void net_dm_queue_len_set(struct genl_info *info)
1300 {
1301 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1302 return;
1303
1304 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1305 }
1306
net_dm_cmd_config(struct sk_buff * skb,struct genl_info * info)1307 static int net_dm_cmd_config(struct sk_buff *skb,
1308 struct genl_info *info)
1309 {
1310 struct netlink_ext_ack *extack = info->extack;
1311 int rc;
1312
1313 if (net_dm_is_monitoring()) {
1314 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1315 return -EBUSY;
1316 }
1317
1318 rc = net_dm_alert_mode_set(info);
1319 if (rc)
1320 return rc;
1321
1322 net_dm_trunc_len_set(info);
1323
1324 net_dm_queue_len_set(info);
1325
1326 return 0;
1327 }
1328
net_dm_monitor_start(bool set_sw,bool set_hw,struct netlink_ext_ack * extack)1329 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1330 struct netlink_ext_ack *extack)
1331 {
1332 bool sw_set = false;
1333 int rc;
1334
1335 if (set_sw) {
1336 rc = set_all_monitor_traces(TRACE_ON, extack);
1337 if (rc)
1338 return rc;
1339 sw_set = true;
1340 }
1341
1342 if (set_hw) {
1343 rc = net_dm_hw_monitor_start(extack);
1344 if (rc)
1345 goto err_monitor_hw;
1346 }
1347
1348 return 0;
1349
1350 err_monitor_hw:
1351 if (sw_set)
1352 set_all_monitor_traces(TRACE_OFF, extack);
1353 return rc;
1354 }
1355
net_dm_monitor_stop(bool set_sw,bool set_hw,struct netlink_ext_ack * extack)1356 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1357 struct netlink_ext_ack *extack)
1358 {
1359 if (set_hw)
1360 net_dm_hw_monitor_stop(extack);
1361 if (set_sw)
1362 set_all_monitor_traces(TRACE_OFF, extack);
1363 }
1364
net_dm_cmd_trace(struct sk_buff * skb,struct genl_info * info)1365 static int net_dm_cmd_trace(struct sk_buff *skb,
1366 struct genl_info *info)
1367 {
1368 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1369 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1370 struct netlink_ext_ack *extack = info->extack;
1371
1372 /* To maintain backward compatibility, we start / stop monitoring of
1373 * software drops if no flag is specified.
1374 */
1375 if (!set_sw && !set_hw)
1376 set_sw = true;
1377
1378 switch (info->genlhdr->cmd) {
1379 case NET_DM_CMD_START:
1380 return net_dm_monitor_start(set_sw, set_hw, extack);
1381 case NET_DM_CMD_STOP:
1382 net_dm_monitor_stop(set_sw, set_hw, extack);
1383 return 0;
1384 }
1385
1386 return -EOPNOTSUPP;
1387 }
1388
net_dm_config_fill(struct sk_buff * msg,struct genl_info * info)1389 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1390 {
1391 void *hdr;
1392
1393 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1394 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1395 if (!hdr)
1396 return -EMSGSIZE;
1397
1398 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1399 goto nla_put_failure;
1400
1401 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1402 goto nla_put_failure;
1403
1404 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1405 goto nla_put_failure;
1406
1407 genlmsg_end(msg, hdr);
1408
1409 return 0;
1410
1411 nla_put_failure:
1412 genlmsg_cancel(msg, hdr);
1413 return -EMSGSIZE;
1414 }
1415
net_dm_cmd_config_get(struct sk_buff * skb,struct genl_info * info)1416 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1417 {
1418 struct sk_buff *msg;
1419 int rc;
1420
1421 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1422 if (!msg)
1423 return -ENOMEM;
1424
1425 rc = net_dm_config_fill(msg, info);
1426 if (rc)
1427 goto free_msg;
1428
1429 return genlmsg_reply(msg, info);
1430
1431 free_msg:
1432 nlmsg_free(msg);
1433 return rc;
1434 }
1435
net_dm_stats_read(struct net_dm_stats * stats)1436 static void net_dm_stats_read(struct net_dm_stats *stats)
1437 {
1438 int cpu;
1439
1440 memset(stats, 0, sizeof(*stats));
1441 for_each_possible_cpu(cpu) {
1442 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1443 struct net_dm_stats *cpu_stats = &data->stats;
1444 unsigned int start;
1445 u64 dropped;
1446
1447 do {
1448 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1449 dropped = u64_stats_read(&cpu_stats->dropped);
1450 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1451
1452 u64_stats_add(&stats->dropped, dropped);
1453 }
1454 }
1455
net_dm_stats_put(struct sk_buff * msg)1456 static int net_dm_stats_put(struct sk_buff *msg)
1457 {
1458 struct net_dm_stats stats;
1459 struct nlattr *attr;
1460
1461 net_dm_stats_read(&stats);
1462
1463 attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1464 if (!attr)
1465 return -EMSGSIZE;
1466
1467 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1468 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1469 goto nla_put_failure;
1470
1471 nla_nest_end(msg, attr);
1472
1473 return 0;
1474
1475 nla_put_failure:
1476 nla_nest_cancel(msg, attr);
1477 return -EMSGSIZE;
1478 }
1479
net_dm_hw_stats_read(struct net_dm_stats * stats)1480 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1481 {
1482 int cpu;
1483
1484 memset(stats, 0, sizeof(*stats));
1485 for_each_possible_cpu(cpu) {
1486 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1487 struct net_dm_stats *cpu_stats = &hw_data->stats;
1488 unsigned int start;
1489 u64 dropped;
1490
1491 do {
1492 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1493 dropped = u64_stats_read(&cpu_stats->dropped);
1494 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1495
1496 u64_stats_add(&stats->dropped, dropped);
1497 }
1498 }
1499
net_dm_hw_stats_put(struct sk_buff * msg)1500 static int net_dm_hw_stats_put(struct sk_buff *msg)
1501 {
1502 struct net_dm_stats stats;
1503 struct nlattr *attr;
1504
1505 net_dm_hw_stats_read(&stats);
1506
1507 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1508 if (!attr)
1509 return -EMSGSIZE;
1510
1511 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1512 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1513 goto nla_put_failure;
1514
1515 nla_nest_end(msg, attr);
1516
1517 return 0;
1518
1519 nla_put_failure:
1520 nla_nest_cancel(msg, attr);
1521 return -EMSGSIZE;
1522 }
1523
net_dm_stats_fill(struct sk_buff * msg,struct genl_info * info)1524 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1525 {
1526 void *hdr;
1527 int rc;
1528
1529 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1530 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1531 if (!hdr)
1532 return -EMSGSIZE;
1533
1534 rc = net_dm_stats_put(msg);
1535 if (rc)
1536 goto nla_put_failure;
1537
1538 rc = net_dm_hw_stats_put(msg);
1539 if (rc)
1540 goto nla_put_failure;
1541
1542 genlmsg_end(msg, hdr);
1543
1544 return 0;
1545
1546 nla_put_failure:
1547 genlmsg_cancel(msg, hdr);
1548 return -EMSGSIZE;
1549 }
1550
net_dm_cmd_stats_get(struct sk_buff * skb,struct genl_info * info)1551 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1552 {
1553 struct sk_buff *msg;
1554 int rc;
1555
1556 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1557 if (!msg)
1558 return -ENOMEM;
1559
1560 rc = net_dm_stats_fill(msg, info);
1561 if (rc)
1562 goto free_msg;
1563
1564 return genlmsg_reply(msg, info);
1565
1566 free_msg:
1567 nlmsg_free(msg);
1568 return rc;
1569 }
1570
dropmon_net_event(struct notifier_block * ev_block,unsigned long event,void * ptr)1571 static int dropmon_net_event(struct notifier_block *ev_block,
1572 unsigned long event, void *ptr)
1573 {
1574 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1575 struct dm_hw_stat_delta *stat;
1576
1577 switch (event) {
1578 case NETDEV_REGISTER:
1579 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1580 break;
1581 stat = kzalloc_obj(*stat);
1582 if (!stat)
1583 break;
1584
1585 stat->last_rx = jiffies;
1586 rcu_assign_pointer(dev->dm_private, stat);
1587
1588 break;
1589 case NETDEV_UNREGISTER:
1590 stat = rtnl_dereference(dev->dm_private);
1591 if (stat) {
1592 rcu_assign_pointer(dev->dm_private, NULL);
1593 kfree_rcu(stat, rcu);
1594 }
1595 break;
1596 }
1597 return NOTIFY_DONE;
1598 }
1599
1600 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1601 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1602 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1603 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1604 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1605 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG },
1606 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG },
1607 };
1608
1609 static const struct genl_small_ops dropmon_ops[] = {
1610 {
1611 .cmd = NET_DM_CMD_CONFIG,
1612 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1613 .doit = net_dm_cmd_config,
1614 .flags = GENL_ADMIN_PERM,
1615 },
1616 {
1617 .cmd = NET_DM_CMD_START,
1618 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1619 .doit = net_dm_cmd_trace,
1620 .flags = GENL_ADMIN_PERM,
1621 },
1622 {
1623 .cmd = NET_DM_CMD_STOP,
1624 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1625 .doit = net_dm_cmd_trace,
1626 .flags = GENL_ADMIN_PERM,
1627 },
1628 {
1629 .cmd = NET_DM_CMD_CONFIG_GET,
1630 .doit = net_dm_cmd_config_get,
1631 },
1632 {
1633 .cmd = NET_DM_CMD_STATS_GET,
1634 .doit = net_dm_cmd_stats_get,
1635 },
1636 };
1637
net_dm_nl_pre_doit(const struct genl_split_ops * ops,struct sk_buff * skb,struct genl_info * info)1638 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
1639 struct sk_buff *skb, struct genl_info *info)
1640 {
1641 mutex_lock(&net_dm_mutex);
1642
1643 return 0;
1644 }
1645
net_dm_nl_post_doit(const struct genl_split_ops * ops,struct sk_buff * skb,struct genl_info * info)1646 static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
1647 struct sk_buff *skb, struct genl_info *info)
1648 {
1649 mutex_unlock(&net_dm_mutex);
1650 }
1651
1652 static struct genl_family net_drop_monitor_family __ro_after_init = {
1653 .hdrsize = 0,
1654 .name = "NET_DM",
1655 .version = 2,
1656 .maxattr = NET_DM_ATTR_MAX,
1657 .policy = net_dm_nl_policy,
1658 .pre_doit = net_dm_nl_pre_doit,
1659 .post_doit = net_dm_nl_post_doit,
1660 .module = THIS_MODULE,
1661 .small_ops = dropmon_ops,
1662 .n_small_ops = ARRAY_SIZE(dropmon_ops),
1663 .resv_start_op = NET_DM_CMD_STATS_GET + 1,
1664 .mcgrps = dropmon_mcgrps,
1665 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps),
1666 };
1667
1668 static struct notifier_block dropmon_net_notifier = {
1669 .notifier_call = dropmon_net_event
1670 };
1671
__net_dm_cpu_data_init(struct per_cpu_dm_data * data)1672 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1673 {
1674 raw_spin_lock_init(&data->lock);
1675 skb_queue_head_init(&data->drop_queue);
1676 u64_stats_init(&data->stats.syncp);
1677 }
1678
__net_dm_cpu_data_fini(struct per_cpu_dm_data * data)1679 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1680 {
1681 WARN_ON(!skb_queue_empty(&data->drop_queue));
1682 }
1683
net_dm_cpu_data_init(int cpu)1684 static void net_dm_cpu_data_init(int cpu)
1685 {
1686 struct per_cpu_dm_data *data;
1687
1688 data = &per_cpu(dm_cpu_data, cpu);
1689 __net_dm_cpu_data_init(data);
1690 }
1691
net_dm_cpu_data_fini(int cpu)1692 static void net_dm_cpu_data_fini(int cpu)
1693 {
1694 struct per_cpu_dm_data *data;
1695
1696 data = &per_cpu(dm_cpu_data, cpu);
1697 /* At this point, we should have exclusive access
1698 * to this struct and can free the skb inside it.
1699 */
1700 consume_skb(data->skb);
1701 __net_dm_cpu_data_fini(data);
1702 }
1703
net_dm_hw_cpu_data_init(int cpu)1704 static void net_dm_hw_cpu_data_init(int cpu)
1705 {
1706 struct per_cpu_dm_data *hw_data;
1707
1708 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1709 __net_dm_cpu_data_init(hw_data);
1710 }
1711
net_dm_hw_cpu_data_fini(int cpu)1712 static void net_dm_hw_cpu_data_fini(int cpu)
1713 {
1714 struct per_cpu_dm_data *hw_data;
1715
1716 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1717 kfree(hw_data->hw_entries);
1718 __net_dm_cpu_data_fini(hw_data);
1719 }
1720
init_net_drop_monitor(void)1721 static int __init init_net_drop_monitor(void)
1722 {
1723 int cpu, rc;
1724
1725 pr_info("Initializing network drop monitor service\n");
1726
1727 if (sizeof(void *) > 8) {
1728 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1729 return -ENOSPC;
1730 }
1731
1732 for_each_possible_cpu(cpu) {
1733 net_dm_cpu_data_init(cpu);
1734 net_dm_hw_cpu_data_init(cpu);
1735 }
1736
1737 rc = register_netdevice_notifier(&dropmon_net_notifier);
1738 if (rc < 0) {
1739 pr_crit("Failed to register netdevice notifier\n");
1740 return rc;
1741 }
1742
1743 rc = genl_register_family(&net_drop_monitor_family);
1744 if (rc) {
1745 pr_err("Could not create drop monitor netlink family\n");
1746 goto out_unreg;
1747 }
1748 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1749
1750 rc = 0;
1751
1752 goto out;
1753
1754 out_unreg:
1755 WARN_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1756 out:
1757 return rc;
1758 }
1759
exit_net_drop_monitor(void)1760 static void exit_net_drop_monitor(void)
1761 {
1762 int cpu;
1763
1764 /*
1765 * Because of the module_get/put we do in the trace state change path
1766 * we are guaranteed not to have any current users when we get here
1767 */
1768 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1769
1770 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1771
1772 for_each_possible_cpu(cpu) {
1773 net_dm_hw_cpu_data_fini(cpu);
1774 net_dm_cpu_data_fini(cpu);
1775 }
1776 }
1777
1778 module_init(init_net_drop_monitor);
1779 module_exit(exit_net_drop_monitor);
1780
1781 MODULE_LICENSE("GPL v2");
1782 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1783 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1784 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");
1785