Commit | Line | Data |
---|---|---|
09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9a8afc8d NH |
2 | /* |
3 | * Monitoring code for network dropped packet alerts | |
4 | * | |
5 | * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com> | |
6 | */ | |
7 | ||
e005d193 JP |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | ||
9a8afc8d NH |
10 | #include <linux/netdevice.h> |
11 | #include <linux/etherdevice.h> | |
12 | #include <linux/string.h> | |
13 | #include <linux/if_arp.h> | |
14 | #include <linux/inetdevice.h> | |
15 | #include <linux/inet.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/netpoll.h> | |
18 | #include <linux/sched.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/types.h> | |
21 | #include <linux/workqueue.h> | |
22 | #include <linux/netlink.h> | |
23 | #include <linux/net_dropmon.h> | |
24 | #include <linux/percpu.h> | |
25 | #include <linux/timer.h> | |
26 | #include <linux/bitops.h> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
cad456d5 | 28 | #include <linux/module.h> |
9a8afc8d | 29 | #include <net/genetlink.h> |
4ea7e386 | 30 | #include <net/netevent.h> |
9a8afc8d | 31 | |
ad8d75ff | 32 | #include <trace/events/skb.h> |
9cbc1cb8 | 33 | #include <trace/events/napi.h> |
9a8afc8d NH |
34 | |
35 | #include <asm/unaligned.h> | |
36 | ||
37 | #define TRACE_ON 1 | |
38 | #define TRACE_OFF 0 | |
39 | ||
9a8afc8d NH |
40 | /* |
41 | * Globals, our netlink socket pointer | |
42 | * and the work handle that will send up | |
43 | * netlink alerts | |
44 | */ | |
4ea7e386 | 45 | static int trace_state = TRACE_OFF; |
cde2e9a6 | 46 | static DEFINE_MUTEX(trace_state_mutex); |
9a8afc8d NH |
47 | |
48 | struct per_cpu_dm_data { | |
bec4596b ED |
49 | spinlock_t lock; |
50 | struct sk_buff *skb; | |
51 | struct work_struct dm_alert_work; | |
52 | struct timer_list send_timer; | |
9a8afc8d NH |
53 | }; |
54 | ||
4ea7e386 NH |
55 | struct dm_hw_stat_delta { |
56 | struct net_device *dev; | |
5848cc09 | 57 | unsigned long last_rx; |
4ea7e386 NH |
58 | struct list_head list; |
59 | struct rcu_head rcu; | |
60 | unsigned long last_drop_val; | |
61 | }; | |
62 | ||
489111e5 | 63 | static struct genl_family net_drop_monitor_family; |
9a8afc8d NH |
64 | |
65 | static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); | |
66 | ||
67 | static int dm_hit_limit = 64; | |
68 | static int dm_delay = 1; | |
4ea7e386 NH |
69 | static unsigned long dm_hw_check_delta = 2*HZ; |
70 | static LIST_HEAD(hw_stats_list); | |
9a8afc8d | 71 | |
bec4596b | 72 | static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) |
9a8afc8d NH |
73 | { |
74 | size_t al; | |
75 | struct net_dm_alert_msg *msg; | |
683703a2 | 76 | struct nlattr *nla; |
3885ca78 | 77 | struct sk_buff *skb; |
bec4596b | 78 | unsigned long flags; |
4200462d | 79 | void *msg_header; |
9a8afc8d NH |
80 | |
81 | al = sizeof(struct net_dm_alert_msg); | |
82 | al += dm_hit_limit * sizeof(struct net_dm_drop_point); | |
683703a2 NH |
83 | al += sizeof(struct nlattr); |
84 | ||
3885ca78 NH |
85 | skb = genlmsg_new(al, GFP_KERNEL); |
86 | ||
4200462d RW |
87 | if (!skb) |
88 | goto err; | |
3885ca78 | 89 | |
4200462d RW |
90 | msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family, |
91 | 0, NET_DM_CMD_ALERT); | |
92 | if (!msg_header) { | |
93 | nlmsg_free(skb); | |
94 | skb = NULL; | |
95 | goto err; | |
96 | } | |
97 | nla = nla_reserve(skb, NLA_UNSPEC, | |
98 | sizeof(struct net_dm_alert_msg)); | |
99 | if (!nla) { | |
100 | nlmsg_free(skb); | |
101 | skb = NULL; | |
102 | goto err; | |
103 | } | |
104 | msg = nla_data(nla); | |
105 | memset(msg, 0, al); | |
4200462d RW |
106 | goto out; |
107 | ||
108 | err: | |
109 | mod_timer(&data->send_timer, jiffies + HZ / 10); | |
110 | out: | |
bec4596b ED |
111 | spin_lock_irqsave(&data->lock, flags); |
112 | swap(data->skb, skb); | |
113 | spin_unlock_irqrestore(&data->lock, flags); | |
114 | ||
3b48ab22 RW |
115 | if (skb) { |
116 | struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; | |
117 | struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh); | |
118 | ||
119 | genlmsg_end(skb, genlmsg_data(gnlh)); | |
120 | } | |
121 | ||
bec4596b | 122 | return skb; |
9a8afc8d NH |
123 | } |
124 | ||
85bae4bd | 125 | static const struct genl_multicast_group dropmon_mcgrps[] = { |
2a94fe48 | 126 | { .name = "events", }, |
e5dcecba JB |
127 | }; |
128 | ||
bec4596b | 129 | static void send_dm_alert(struct work_struct *work) |
9a8afc8d NH |
130 | { |
131 | struct sk_buff *skb; | |
bec4596b | 132 | struct per_cpu_dm_data *data; |
9a8afc8d | 133 | |
bec4596b | 134 | data = container_of(work, struct per_cpu_dm_data, dm_alert_work); |
4fdcfa12 | 135 | |
bec4596b | 136 | skb = reset_per_cpu_data(data); |
9a8afc8d | 137 | |
3885ca78 | 138 | if (skb) |
68eb5503 | 139 | genlmsg_multicast(&net_drop_monitor_family, skb, 0, |
2a94fe48 | 140 | 0, GFP_KERNEL); |
9a8afc8d NH |
141 | } |
142 | ||
143 | /* | |
144 | * This is the timer function to delay the sending of an alert | |
145 | * in the event that more drops will arrive during the | |
bec4596b | 146 | * hysteresis period. |
9a8afc8d | 147 | */ |
e99e88a9 | 148 | static void sched_send_work(struct timer_list *t) |
9a8afc8d | 149 | { |
e99e88a9 | 150 | struct per_cpu_dm_data *data = from_timer(data, t, send_timer); |
3885ca78 | 151 | |
bec4596b | 152 | schedule_work(&data->dm_alert_work); |
9a8afc8d NH |
153 | } |
154 | ||
4ea7e386 | 155 | static void trace_drop_common(struct sk_buff *skb, void *location) |
9a8afc8d NH |
156 | { |
157 | struct net_dm_alert_msg *msg; | |
158 | struct nlmsghdr *nlh; | |
683703a2 | 159 | struct nlattr *nla; |
9a8afc8d | 160 | int i; |
3885ca78 | 161 | struct sk_buff *dskb; |
bec4596b ED |
162 | struct per_cpu_dm_data *data; |
163 | unsigned long flags; | |
9a8afc8d | 164 | |
bec4596b | 165 | local_irq_save(flags); |
903ceff7 | 166 | data = this_cpu_ptr(&dm_cpu_data); |
bec4596b ED |
167 | spin_lock(&data->lock); |
168 | dskb = data->skb; | |
3885ca78 NH |
169 | |
170 | if (!dskb) | |
171 | goto out; | |
172 | ||
3885ca78 | 173 | nlh = (struct nlmsghdr *)dskb->data; |
683703a2 NH |
174 | nla = genlmsg_data(nlmsg_data(nlh)); |
175 | msg = nla_data(nla); | |
9a8afc8d NH |
176 | for (i = 0; i < msg->entries; i++) { |
177 | if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) { | |
178 | msg->points[i].count++; | |
179 | goto out; | |
180 | } | |
181 | } | |
bec4596b ED |
182 | if (msg->entries == dm_hit_limit) |
183 | goto out; | |
9a8afc8d NH |
184 | /* |
185 | * We need to create a new entry | |
186 | */ | |
3885ca78 | 187 | __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point)); |
683703a2 | 188 | nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); |
9a8afc8d NH |
189 | memcpy(msg->points[msg->entries].pc, &location, sizeof(void *)); |
190 | msg->points[msg->entries].count = 1; | |
191 | msg->entries++; | |
192 | ||
193 | if (!timer_pending(&data->send_timer)) { | |
194 | data->send_timer.expires = jiffies + dm_delay * HZ; | |
bec4596b | 195 | add_timer(&data->send_timer); |
9a8afc8d NH |
196 | } |
197 | ||
198 | out: | |
bec4596b | 199 | spin_unlock_irqrestore(&data->lock, flags); |
9a8afc8d NH |
200 | } |
201 | ||
38516ab5 | 202 | static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location) |
4ea7e386 NH |
203 | { |
204 | trace_drop_common(skb, location); | |
205 | } | |
206 | ||
1db19db7 JDB |
207 | static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, |
208 | int work, int budget) | |
4ea7e386 NH |
209 | { |
210 | struct dm_hw_stat_delta *new_stat; | |
211 | ||
212 | /* | |
5848cc09 | 213 | * Don't check napi structures with no associated device |
4ea7e386 | 214 | */ |
5848cc09 | 215 | if (!napi->dev) |
4ea7e386 NH |
216 | return; |
217 | ||
218 | rcu_read_lock(); | |
219 | list_for_each_entry_rcu(new_stat, &hw_stats_list, list) { | |
5848cc09 NH |
220 | /* |
221 | * only add a note to our monitor buffer if: | |
222 | * 1) this is the dev we received on | |
223 | * 2) its after the last_rx delta | |
224 | * 3) our rx_dropped count has gone up | |
225 | */ | |
4ea7e386 | 226 | if ((new_stat->dev == napi->dev) && |
5848cc09 | 227 | (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) && |
4ea7e386 NH |
228 | (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) { |
229 | trace_drop_common(NULL, NULL); | |
230 | new_stat->last_drop_val = napi->dev->stats.rx_dropped; | |
5848cc09 | 231 | new_stat->last_rx = jiffies; |
4ea7e386 NH |
232 | break; |
233 | } | |
234 | } | |
235 | rcu_read_unlock(); | |
236 | } | |
237 | ||
9a8afc8d NH |
238 | static int set_all_monitor_traces(int state) |
239 | { | |
240 | int rc = 0; | |
4ea7e386 NH |
241 | struct dm_hw_stat_delta *new_stat = NULL; |
242 | struct dm_hw_stat_delta *temp; | |
243 | ||
cde2e9a6 | 244 | mutex_lock(&trace_state_mutex); |
9a8afc8d | 245 | |
4b706372 NH |
246 | if (state == trace_state) { |
247 | rc = -EAGAIN; | |
248 | goto out_unlock; | |
249 | } | |
250 | ||
9a8afc8d NH |
251 | switch (state) { |
252 | case TRACE_ON: | |
cad456d5 NH |
253 | if (!try_module_get(THIS_MODULE)) { |
254 | rc = -ENODEV; | |
255 | break; | |
256 | } | |
257 | ||
38516ab5 SR |
258 | rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL); |
259 | rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL); | |
9a8afc8d | 260 | break; |
cad456d5 | 261 | |
9a8afc8d | 262 | case TRACE_OFF: |
38516ab5 SR |
263 | rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL); |
264 | rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL); | |
9a8afc8d NH |
265 | |
266 | tracepoint_synchronize_unregister(); | |
4ea7e386 NH |
267 | |
268 | /* | |
269 | * Clean the device list | |
270 | */ | |
271 | list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { | |
272 | if (new_stat->dev == NULL) { | |
273 | list_del_rcu(&new_stat->list); | |
fa81c0e1 | 274 | kfree_rcu(new_stat, rcu); |
4ea7e386 NH |
275 | } |
276 | } | |
cad456d5 NH |
277 | |
278 | module_put(THIS_MODULE); | |
279 | ||
9a8afc8d NH |
280 | break; |
281 | default: | |
282 | rc = 1; | |
283 | break; | |
284 | } | |
285 | ||
4ea7e386 NH |
286 | if (!rc) |
287 | trace_state = state; | |
4b706372 NH |
288 | else |
289 | rc = -EINPROGRESS; | |
4ea7e386 | 290 | |
4b706372 | 291 | out_unlock: |
cde2e9a6 | 292 | mutex_unlock(&trace_state_mutex); |
4ea7e386 | 293 | |
9a8afc8d NH |
294 | return rc; |
295 | } | |
296 | ||
297 | ||
298 | static int net_dm_cmd_config(struct sk_buff *skb, | |
299 | struct genl_info *info) | |
300 | { | |
301 | return -ENOTSUPP; | |
302 | } | |
303 | ||
304 | static int net_dm_cmd_trace(struct sk_buff *skb, | |
305 | struct genl_info *info) | |
306 | { | |
307 | switch (info->genlhdr->cmd) { | |
308 | case NET_DM_CMD_START: | |
309 | return set_all_monitor_traces(TRACE_ON); | |
9a8afc8d NH |
310 | case NET_DM_CMD_STOP: |
311 | return set_all_monitor_traces(TRACE_OFF); | |
9a8afc8d NH |
312 | } |
313 | ||
314 | return -ENOTSUPP; | |
315 | } | |
316 | ||
4ea7e386 | 317 | static int dropmon_net_event(struct notifier_block *ev_block, |
351638e7 | 318 | unsigned long event, void *ptr) |
4ea7e386 | 319 | { |
351638e7 | 320 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
4ea7e386 NH |
321 | struct dm_hw_stat_delta *new_stat = NULL; |
322 | struct dm_hw_stat_delta *tmp; | |
323 | ||
324 | switch (event) { | |
325 | case NETDEV_REGISTER: | |
326 | new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); | |
327 | ||
328 | if (!new_stat) | |
329 | goto out; | |
330 | ||
331 | new_stat->dev = dev; | |
5848cc09 | 332 | new_stat->last_rx = jiffies; |
cde2e9a6 | 333 | mutex_lock(&trace_state_mutex); |
4ea7e386 | 334 | list_add_rcu(&new_stat->list, &hw_stats_list); |
cde2e9a6 | 335 | mutex_unlock(&trace_state_mutex); |
4ea7e386 NH |
336 | break; |
337 | case NETDEV_UNREGISTER: | |
cde2e9a6 | 338 | mutex_lock(&trace_state_mutex); |
4ea7e386 NH |
339 | list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { |
340 | if (new_stat->dev == dev) { | |
341 | new_stat->dev = NULL; | |
342 | if (trace_state == TRACE_OFF) { | |
343 | list_del_rcu(&new_stat->list); | |
fa81c0e1 | 344 | kfree_rcu(new_stat, rcu); |
4ea7e386 NH |
345 | break; |
346 | } | |
347 | } | |
348 | } | |
cde2e9a6 | 349 | mutex_unlock(&trace_state_mutex); |
4ea7e386 NH |
350 | break; |
351 | } | |
352 | out: | |
353 | return NOTIFY_DONE; | |
354 | } | |
9a8afc8d | 355 | |
4534de83 | 356 | static const struct genl_ops dropmon_ops[] = { |
9a8afc8d NH |
357 | { |
358 | .cmd = NET_DM_CMD_CONFIG, | |
ef6243ac | 359 | .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, |
9a8afc8d NH |
360 | .doit = net_dm_cmd_config, |
361 | }, | |
362 | { | |
363 | .cmd = NET_DM_CMD_START, | |
ef6243ac | 364 | .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, |
9a8afc8d NH |
365 | .doit = net_dm_cmd_trace, |
366 | }, | |
367 | { | |
368 | .cmd = NET_DM_CMD_STOP, | |
ef6243ac | 369 | .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, |
9a8afc8d NH |
370 | .doit = net_dm_cmd_trace, |
371 | }, | |
372 | }; | |
373 | ||
56989f6d | 374 | static struct genl_family net_drop_monitor_family __ro_after_init = { |
489111e5 JB |
375 | .hdrsize = 0, |
376 | .name = "NET_DM", | |
377 | .version = 2, | |
378 | .module = THIS_MODULE, | |
379 | .ops = dropmon_ops, | |
380 | .n_ops = ARRAY_SIZE(dropmon_ops), | |
381 | .mcgrps = dropmon_mcgrps, | |
382 | .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), | |
383 | }; | |
384 | ||
4ea7e386 NH |
385 | static struct notifier_block dropmon_net_notifier = { |
386 | .notifier_call = dropmon_net_event | |
387 | }; | |
388 | ||
9a8afc8d NH |
389 | static int __init init_net_drop_monitor(void) |
390 | { | |
9a8afc8d | 391 | struct per_cpu_dm_data *data; |
a256be70 CG |
392 | int cpu, rc; |
393 | ||
e005d193 | 394 | pr_info("Initializing network drop monitor service\n"); |
9a8afc8d NH |
395 | |
396 | if (sizeof(void *) > 8) { | |
e005d193 | 397 | pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); |
9a8afc8d NH |
398 | return -ENOSPC; |
399 | } | |
400 | ||
489111e5 | 401 | rc = genl_register_family(&net_drop_monitor_family); |
a256be70 | 402 | if (rc) { |
e005d193 | 403 | pr_err("Could not create drop monitor netlink family\n"); |
a256be70 | 404 | return rc; |
9a8afc8d | 405 | } |
2a94fe48 | 406 | WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); |
e5dcecba | 407 | |
4ea7e386 NH |
408 | rc = register_netdevice_notifier(&dropmon_net_notifier); |
409 | if (rc < 0) { | |
e005d193 | 410 | pr_crit("Failed to register netdevice notifier\n"); |
4ea7e386 NH |
411 | goto out_unreg; |
412 | } | |
413 | ||
9a8afc8d NH |
414 | rc = 0; |
415 | ||
cad456d5 | 416 | for_each_possible_cpu(cpu) { |
9a8afc8d | 417 | data = &per_cpu(dm_cpu_data, cpu); |
9a8afc8d | 418 | INIT_WORK(&data->dm_alert_work, send_dm_alert); |
e99e88a9 | 419 | timer_setup(&data->send_timer, sched_send_work, 0); |
bec4596b | 420 | spin_lock_init(&data->lock); |
4fdcfa12 | 421 | reset_per_cpu_data(data); |
9a8afc8d | 422 | } |
4ea7e386 | 423 | |
3885ca78 | 424 | |
9a8afc8d NH |
425 | goto out; |
426 | ||
427 | out_unreg: | |
428 | genl_unregister_family(&net_drop_monitor_family); | |
429 | out: | |
430 | return rc; | |
431 | } | |
432 | ||
cad456d5 NH |
433 | static void exit_net_drop_monitor(void) |
434 | { | |
435 | struct per_cpu_dm_data *data; | |
436 | int cpu; | |
437 | ||
438 | BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); | |
439 | ||
440 | /* | |
441 | * Because of the module_get/put we do in the trace state change path | |
442 | * we are guarnateed not to have any current users when we get here | |
443 | * all we need to do is make sure that we don't have any running timers | |
444 | * or pending schedule calls | |
445 | */ | |
446 | ||
447 | for_each_possible_cpu(cpu) { | |
448 | data = &per_cpu(dm_cpu_data, cpu); | |
449 | del_timer_sync(&data->send_timer); | |
450 | cancel_work_sync(&data->dm_alert_work); | |
451 | /* | |
452 | * At this point, we should have exclusive access | |
453 | * to this struct and can free the skb inside it | |
454 | */ | |
455 | kfree_skb(data->skb); | |
456 | } | |
457 | ||
458 | BUG_ON(genl_unregister_family(&net_drop_monitor_family)); | |
459 | } | |
460 | ||
461 | module_init(init_net_drop_monitor); | |
462 | module_exit(exit_net_drop_monitor); | |
463 | ||
464 | MODULE_LICENSE("GPL v2"); | |
465 | MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); | |
3fdcbd45 | 466 | MODULE_ALIAS_GENL_FAMILY("NET_DM"); |