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