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