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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// 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/percpu.h>
25#include <linux/timer.h>
26#include <linux/bitops.h>
27#include <linux/slab.h>
28#include <linux/module.h>
29#include <net/genetlink.h>
30#include <net/netevent.h>
31#include <net/flow_offload.h>
32#include <net/devlink.h>
33
34#include <trace/events/skb.h>
35#include <trace/events/napi.h>
36#include <trace/events/devlink.h>
37
38#include <asm/unaligned.h>
39
40#define TRACE_ON 1
41#define TRACE_OFF 0
42
43/*
44 * Globals, our netlink socket pointer
45 * and the work handle that will send up
46 * netlink alerts
47 */
48static int trace_state = TRACE_OFF;
49static bool monitor_hw;
50
51/* net_dm_mutex
52 *
53 * An overall lock guarding every operation coming from userspace.
54 */
55static DEFINE_MUTEX(net_dm_mutex);
56
57struct net_dm_stats {
58 u64_stats_t dropped;
59 struct u64_stats_sync syncp;
60};
61
62#define NET_DM_MAX_HW_TRAP_NAME_LEN 40
63
64struct net_dm_hw_entry {
65 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
66 u32 count;
67};
68
69struct net_dm_hw_entries {
70 u32 num_entries;
71 struct net_dm_hw_entry entries[];
72};
73
74struct per_cpu_dm_data {
75 spinlock_t lock; /* Protects 'skb', 'hw_entries' and
76 * 'send_timer'
77 */
78 union {
79 struct sk_buff *skb;
80 struct net_dm_hw_entries *hw_entries;
81 };
82 struct sk_buff_head drop_queue;
83 struct work_struct dm_alert_work;
84 struct timer_list send_timer;
85 struct net_dm_stats stats;
86};
87
88struct dm_hw_stat_delta {
89 unsigned long last_rx;
90 unsigned long last_drop_val;
91 struct rcu_head rcu;
92};
93
94static struct genl_family net_drop_monitor_family;
95
96static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
97static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
98
99static int dm_hit_limit = 64;
100static int dm_delay = 1;
101static unsigned long dm_hw_check_delta = 2*HZ;
102
103static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
104static u32 net_dm_trunc_len;
105static u32 net_dm_queue_len = 1000;
106
107struct net_dm_alert_ops {
108 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
109 void *location,
110 enum skb_drop_reason reason);
111 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
112 int work, int budget);
113 void (*work_item_func)(struct work_struct *work);
114 void (*hw_work_item_func)(struct work_struct *work);
115 void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
116 struct sk_buff *skb,
117 const struct devlink_trap_metadata *metadata);
118};
119
120struct net_dm_skb_cb {
121 union {
122 struct devlink_trap_metadata *hw_metadata;
123 void *pc;
124 };
125 enum skb_drop_reason reason;
126};
127
128#define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
129
130static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
131{
132 size_t al;
133 struct net_dm_alert_msg *msg;
134 struct nlattr *nla;
135 struct sk_buff *skb;
136 unsigned long flags;
137 void *msg_header;
138
139 al = sizeof(struct net_dm_alert_msg);
140 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
141 al += sizeof(struct nlattr);
142
143 skb = genlmsg_new(al, GFP_KERNEL);
144
145 if (!skb)
146 goto err;
147
148 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
149 0, NET_DM_CMD_ALERT);
150 if (!msg_header) {
151 nlmsg_free(skb);
152 skb = NULL;
153 goto err;
154 }
155 nla = nla_reserve(skb, NLA_UNSPEC,
156 sizeof(struct net_dm_alert_msg));
157 if (!nla) {
158 nlmsg_free(skb);
159 skb = NULL;
160 goto err;
161 }
162 msg = nla_data(nla);
163 memset(msg, 0, al);
164 goto out;
165
166err:
167 mod_timer(&data->send_timer, jiffies + HZ / 10);
168out:
169 spin_lock_irqsave(&data->lock, flags);
170 swap(data->skb, skb);
171 spin_unlock_irqrestore(&data->lock, flags);
172
173 if (skb) {
174 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
175 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
176
177 genlmsg_end(skb, genlmsg_data(gnlh));
178 }
179
180 return skb;
181}
182
183static const struct genl_multicast_group dropmon_mcgrps[] = {
184 { .name = "events", },
185};
186
187static void send_dm_alert(struct work_struct *work)
188{
189 struct sk_buff *skb;
190 struct per_cpu_dm_data *data;
191
192 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
193
194 skb = reset_per_cpu_data(data);
195
196 if (skb)
197 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
198 0, GFP_KERNEL);
199}
200
201/*
202 * This is the timer function to delay the sending of an alert
203 * in the event that more drops will arrive during the
204 * hysteresis period.
205 */
206static void sched_send_work(struct timer_list *t)
207{
208 struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
209
210 schedule_work(&data->dm_alert_work);
211}
212
213static void trace_drop_common(struct sk_buff *skb, void *location)
214{
215 struct net_dm_alert_msg *msg;
216 struct net_dm_drop_point *point;
217 struct nlmsghdr *nlh;
218 struct nlattr *nla;
219 int i;
220 struct sk_buff *dskb;
221 struct per_cpu_dm_data *data;
222 unsigned long flags;
223
224 local_irq_save(flags);
225 data = this_cpu_ptr(&dm_cpu_data);
226 spin_lock(&data->lock);
227 dskb = data->skb;
228
229 if (!dskb)
230 goto out;
231
232 nlh = (struct nlmsghdr *)dskb->data;
233 nla = genlmsg_data(nlmsg_data(nlh));
234 msg = nla_data(nla);
235 point = msg->points;
236 for (i = 0; i < msg->entries; i++) {
237 if (!memcmp(&location, &point->pc, sizeof(void *))) {
238 point->count++;
239 goto out;
240 }
241 point++;
242 }
243 if (msg->entries == dm_hit_limit)
244 goto out;
245 /*
246 * We need to create a new entry
247 */
248 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
249 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
250 memcpy(point->pc, &location, sizeof(void *));
251 point->count = 1;
252 msg->entries++;
253
254 if (!timer_pending(&data->send_timer)) {
255 data->send_timer.expires = jiffies + dm_delay * HZ;
256 add_timer(&data->send_timer);
257 }
258
259out:
260 spin_unlock_irqrestore(&data->lock, flags);
261}
262
263static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
264 void *location,
265 enum skb_drop_reason reason)
266{
267 trace_drop_common(skb, location);
268}
269
270static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
271 int work, int budget)
272{
273 struct net_device *dev = napi->dev;
274 struct dm_hw_stat_delta *stat;
275 /*
276 * Don't check napi structures with no associated device
277 */
278 if (!dev)
279 return;
280
281 rcu_read_lock();
282 stat = rcu_dereference(dev->dm_private);
283 if (stat) {
284 /*
285 * only add a note to our monitor buffer if:
286 * 1) its after the last_rx delta
287 * 2) our rx_dropped count has gone up
288 */
289 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) &&
290 (dev->stats.rx_dropped != stat->last_drop_val)) {
291 trace_drop_common(NULL, NULL);
292 stat->last_drop_val = dev->stats.rx_dropped;
293 stat->last_rx = jiffies;
294 }
295 }
296 rcu_read_unlock();
297}
298
299static struct net_dm_hw_entries *
300net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
301{
302 struct net_dm_hw_entries *hw_entries;
303 unsigned long flags;
304
305 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
306 GFP_KERNEL);
307 if (!hw_entries) {
308 /* If the memory allocation failed, we try to perform another
309 * allocation in 1/10 second. Otherwise, the probe function
310 * will constantly bail out.
311 */
312 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
313 }
314
315 spin_lock_irqsave(&hw_data->lock, flags);
316 swap(hw_data->hw_entries, hw_entries);
317 spin_unlock_irqrestore(&hw_data->lock, flags);
318
319 return hw_entries;
320}
321
322static int net_dm_hw_entry_put(struct sk_buff *msg,
323 const struct net_dm_hw_entry *hw_entry)
324{
325 struct nlattr *attr;
326
327 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
328 if (!attr)
329 return -EMSGSIZE;
330
331 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
332 goto nla_put_failure;
333
334 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
335 goto nla_put_failure;
336
337 nla_nest_end(msg, attr);
338
339 return 0;
340
341nla_put_failure:
342 nla_nest_cancel(msg, attr);
343 return -EMSGSIZE;
344}
345
346static int net_dm_hw_entries_put(struct sk_buff *msg,
347 const struct net_dm_hw_entries *hw_entries)
348{
349 struct nlattr *attr;
350 int i;
351
352 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
353 if (!attr)
354 return -EMSGSIZE;
355
356 for (i = 0; i < hw_entries->num_entries; i++) {
357 int rc;
358
359 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
360 if (rc)
361 goto nla_put_failure;
362 }
363
364 nla_nest_end(msg, attr);
365
366 return 0;
367
368nla_put_failure:
369 nla_nest_cancel(msg, attr);
370 return -EMSGSIZE;
371}
372
373static int
374net_dm_hw_summary_report_fill(struct sk_buff *msg,
375 const struct net_dm_hw_entries *hw_entries)
376{
377 struct net_dm_alert_msg anc_hdr = { 0 };
378 void *hdr;
379 int rc;
380
381 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
382 NET_DM_CMD_ALERT);
383 if (!hdr)
384 return -EMSGSIZE;
385
386 /* We need to put the ancillary header in order not to break user
387 * space.
388 */
389 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
390 goto nla_put_failure;
391
392 rc = net_dm_hw_entries_put(msg, hw_entries);
393 if (rc)
394 goto nla_put_failure;
395
396 genlmsg_end(msg, hdr);
397
398 return 0;
399
400nla_put_failure:
401 genlmsg_cancel(msg, hdr);
402 return -EMSGSIZE;
403}
404
405static void net_dm_hw_summary_work(struct work_struct *work)
406{
407 struct net_dm_hw_entries *hw_entries;
408 struct per_cpu_dm_data *hw_data;
409 struct sk_buff *msg;
410 int rc;
411
412 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
413
414 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
415 if (!hw_entries)
416 return;
417
418 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
419 if (!msg)
420 goto out;
421
422 rc = net_dm_hw_summary_report_fill(msg, hw_entries);
423 if (rc) {
424 nlmsg_free(msg);
425 goto out;
426 }
427
428 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
429
430out:
431 kfree(hw_entries);
432}
433
434static void
435net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
436 struct sk_buff *skb,
437 const struct devlink_trap_metadata *metadata)
438{
439 struct net_dm_hw_entries *hw_entries;
440 struct net_dm_hw_entry *hw_entry;
441 struct per_cpu_dm_data *hw_data;
442 unsigned long flags;
443 int i;
444
445 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
446 return;
447
448 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
449 spin_lock_irqsave(&hw_data->lock, flags);
450 hw_entries = hw_data->hw_entries;
451
452 if (!hw_entries)
453 goto out;
454
455 for (i = 0; i < hw_entries->num_entries; i++) {
456 hw_entry = &hw_entries->entries[i];
457 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
458 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
459 hw_entry->count++;
460 goto out;
461 }
462 }
463 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
464 goto out;
465
466 hw_entry = &hw_entries->entries[hw_entries->num_entries];
467 strscpy(hw_entry->trap_name, metadata->trap_name,
468 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
469 hw_entry->count = 1;
470 hw_entries->num_entries++;
471
472 if (!timer_pending(&hw_data->send_timer)) {
473 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
474 add_timer(&hw_data->send_timer);
475 }
476
477out:
478 spin_unlock_irqrestore(&hw_data->lock, flags);
479}
480
481static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
482 .kfree_skb_probe = trace_kfree_skb_hit,
483 .napi_poll_probe = trace_napi_poll_hit,
484 .work_item_func = send_dm_alert,
485 .hw_work_item_func = net_dm_hw_summary_work,
486 .hw_trap_probe = net_dm_hw_trap_summary_probe,
487};
488
489static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
490 struct sk_buff *skb,
491 void *location,
492 enum skb_drop_reason reason)
493{
494 ktime_t tstamp = ktime_get_real();
495 struct per_cpu_dm_data *data;
496 struct net_dm_skb_cb *cb;
497 struct sk_buff *nskb;
498 unsigned long flags;
499
500 if (!skb_mac_header_was_set(skb))
501 return;
502
503 nskb = skb_clone(skb, GFP_ATOMIC);
504 if (!nskb)
505 return;
506
507 if (unlikely(reason >= SKB_DROP_REASON_MAX || reason <= 0))
508 reason = SKB_DROP_REASON_NOT_SPECIFIED;
509 cb = NET_DM_SKB_CB(nskb);
510 cb->reason = reason;
511 cb->pc = location;
512 /* Override the timestamp because we care about the time when the
513 * packet was dropped.
514 */
515 nskb->tstamp = tstamp;
516
517 data = this_cpu_ptr(&dm_cpu_data);
518
519 spin_lock_irqsave(&data->drop_queue.lock, flags);
520 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
521 __skb_queue_tail(&data->drop_queue, nskb);
522 else
523 goto unlock_free;
524 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
525
526 schedule_work(&data->dm_alert_work);
527
528 return;
529
530unlock_free:
531 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
532 u64_stats_update_begin(&data->stats.syncp);
533 u64_stats_inc(&data->stats.dropped);
534 u64_stats_update_end(&data->stats.syncp);
535 consume_skb(nskb);
536}
537
538static void net_dm_packet_trace_napi_poll_hit(void *ignore,
539 struct napi_struct *napi,
540 int work, int budget)
541{
542}
543
544static size_t net_dm_in_port_size(void)
545{
546 /* NET_DM_ATTR_IN_PORT nest */
547 return nla_total_size(0) +
548 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
549 nla_total_size(sizeof(u32)) +
550 /* NET_DM_ATTR_PORT_NETDEV_NAME */
551 nla_total_size(IFNAMSIZ + 1);
552}
553
554#define NET_DM_MAX_SYMBOL_LEN 40
555
556static size_t net_dm_packet_report_size(size_t payload_len,
557 enum skb_drop_reason reason)
558{
559 size_t size;
560
561 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
562
563 return NLMSG_ALIGN(size) +
564 /* NET_DM_ATTR_ORIGIN */
565 nla_total_size(sizeof(u16)) +
566 /* NET_DM_ATTR_PC */
567 nla_total_size(sizeof(u64)) +
568 /* NET_DM_ATTR_SYMBOL */
569 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
570 /* NET_DM_ATTR_IN_PORT */
571 net_dm_in_port_size() +
572 /* NET_DM_ATTR_TIMESTAMP */
573 nla_total_size(sizeof(u64)) +
574 /* NET_DM_ATTR_ORIG_LEN */
575 nla_total_size(sizeof(u32)) +
576 /* NET_DM_ATTR_PROTO */
577 nla_total_size(sizeof(u16)) +
578 /* NET_DM_ATTR_REASON */
579 nla_total_size(strlen(drop_reasons[reason]) + 1) +
580 /* NET_DM_ATTR_PAYLOAD */
581 nla_total_size(payload_len);
582}
583
584static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
585 const char *name)
586{
587 struct nlattr *attr;
588
589 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
590 if (!attr)
591 return -EMSGSIZE;
592
593 if (ifindex &&
594 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
595 goto nla_put_failure;
596
597 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
598 goto nla_put_failure;
599
600 nla_nest_end(msg, attr);
601
602 return 0;
603
604nla_put_failure:
605 nla_nest_cancel(msg, attr);
606 return -EMSGSIZE;
607}
608
609static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
610 size_t payload_len)
611{
612 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
613 char buf[NET_DM_MAX_SYMBOL_LEN];
614 struct nlattr *attr;
615 void *hdr;
616 int rc;
617
618 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
619 NET_DM_CMD_PACKET_ALERT);
620 if (!hdr)
621 return -EMSGSIZE;
622
623 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
624 goto nla_put_failure;
625
626 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc,
627 NET_DM_ATTR_PAD))
628 goto nla_put_failure;
629
630 if (nla_put_string(msg, NET_DM_ATTR_REASON,
631 drop_reasons[cb->reason]))
632 goto nla_put_failure;
633
634 snprintf(buf, sizeof(buf), "%pS", cb->pc);
635 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
636 goto nla_put_failure;
637
638 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
639 if (rc)
640 goto nla_put_failure;
641
642 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
643 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
644 goto nla_put_failure;
645
646 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
647 goto nla_put_failure;
648
649 if (!payload_len)
650 goto out;
651
652 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
653 goto nla_put_failure;
654
655 attr = skb_put(msg, nla_total_size(payload_len));
656 attr->nla_type = NET_DM_ATTR_PAYLOAD;
657 attr->nla_len = nla_attr_size(payload_len);
658 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
659 goto nla_put_failure;
660
661out:
662 genlmsg_end(msg, hdr);
663
664 return 0;
665
666nla_put_failure:
667 genlmsg_cancel(msg, hdr);
668 return -EMSGSIZE;
669}
670
671#define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
672
673static void net_dm_packet_report(struct sk_buff *skb)
674{
675 struct sk_buff *msg;
676 size_t payload_len;
677 int rc;
678
679 /* Make sure we start copying the packet from the MAC header */
680 if (skb->data > skb_mac_header(skb))
681 skb_push(skb, skb->data - skb_mac_header(skb));
682 else
683 skb_pull(skb, skb_mac_header(skb) - skb->data);
684
685 /* Ensure packet fits inside a single netlink attribute */
686 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
687 if (net_dm_trunc_len)
688 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
689
690 msg = nlmsg_new(net_dm_packet_report_size(payload_len,
691 NET_DM_SKB_CB(skb)->reason),
692 GFP_KERNEL);
693 if (!msg)
694 goto out;
695
696 rc = net_dm_packet_report_fill(msg, skb, payload_len);
697 if (rc) {
698 nlmsg_free(msg);
699 goto out;
700 }
701
702 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
703
704out:
705 consume_skb(skb);
706}
707
708static void net_dm_packet_work(struct work_struct *work)
709{
710 struct per_cpu_dm_data *data;
711 struct sk_buff_head list;
712 struct sk_buff *skb;
713 unsigned long flags;
714
715 data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
716
717 __skb_queue_head_init(&list);
718
719 spin_lock_irqsave(&data->drop_queue.lock, flags);
720 skb_queue_splice_tail_init(&data->drop_queue, &list);
721 spin_unlock_irqrestore(&data->drop_queue.lock, flags);
722
723 while ((skb = __skb_dequeue(&list)))
724 net_dm_packet_report(skb);
725}
726
727static size_t
728net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
729{
730 return hw_metadata->fa_cookie ?
731 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
732}
733
734static size_t
735net_dm_hw_packet_report_size(size_t payload_len,
736 const struct devlink_trap_metadata *hw_metadata)
737{
738 size_t size;
739
740 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
741
742 return NLMSG_ALIGN(size) +
743 /* NET_DM_ATTR_ORIGIN */
744 nla_total_size(sizeof(u16)) +
745 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
746 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
747 /* NET_DM_ATTR_HW_TRAP_NAME */
748 nla_total_size(strlen(hw_metadata->trap_name) + 1) +
749 /* NET_DM_ATTR_IN_PORT */
750 net_dm_in_port_size() +
751 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
752 net_dm_flow_action_cookie_size(hw_metadata) +
753 /* NET_DM_ATTR_TIMESTAMP */
754 nla_total_size(sizeof(u64)) +
755 /* NET_DM_ATTR_ORIG_LEN */
756 nla_total_size(sizeof(u32)) +
757 /* NET_DM_ATTR_PROTO */
758 nla_total_size(sizeof(u16)) +
759 /* NET_DM_ATTR_PAYLOAD */
760 nla_total_size(payload_len);
761}
762
763static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
764 struct sk_buff *skb, size_t payload_len)
765{
766 struct devlink_trap_metadata *hw_metadata;
767 struct nlattr *attr;
768 void *hdr;
769
770 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
771
772 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
773 NET_DM_CMD_PACKET_ALERT);
774 if (!hdr)
775 return -EMSGSIZE;
776
777 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
778 goto nla_put_failure;
779
780 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
781 hw_metadata->trap_group_name))
782 goto nla_put_failure;
783
784 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
785 hw_metadata->trap_name))
786 goto nla_put_failure;
787
788 if (hw_metadata->input_dev) {
789 struct net_device *dev = hw_metadata->input_dev;
790 int rc;
791
792 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
793 dev->name);
794 if (rc)
795 goto nla_put_failure;
796 }
797
798 if (hw_metadata->fa_cookie &&
799 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
800 hw_metadata->fa_cookie->cookie_len,
801 hw_metadata->fa_cookie->cookie))
802 goto nla_put_failure;
803
804 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
805 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
806 goto nla_put_failure;
807
808 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
809 goto nla_put_failure;
810
811 if (!payload_len)
812 goto out;
813
814 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
815 goto nla_put_failure;
816
817 attr = skb_put(msg, nla_total_size(payload_len));
818 attr->nla_type = NET_DM_ATTR_PAYLOAD;
819 attr->nla_len = nla_attr_size(payload_len);
820 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
821 goto nla_put_failure;
822
823out:
824 genlmsg_end(msg, hdr);
825
826 return 0;
827
828nla_put_failure:
829 genlmsg_cancel(msg, hdr);
830 return -EMSGSIZE;
831}
832
833static struct devlink_trap_metadata *
834net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
835{
836 const struct flow_action_cookie *fa_cookie;
837 struct devlink_trap_metadata *hw_metadata;
838 const char *trap_group_name;
839 const char *trap_name;
840
841 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
842 if (!hw_metadata)
843 return NULL;
844
845 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
846 if (!trap_group_name)
847 goto free_hw_metadata;
848 hw_metadata->trap_group_name = trap_group_name;
849
850 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
851 if (!trap_name)
852 goto free_trap_group;
853 hw_metadata->trap_name = trap_name;
854
855 if (metadata->fa_cookie) {
856 size_t cookie_size = sizeof(*fa_cookie) +
857 metadata->fa_cookie->cookie_len;
858
859 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
860 GFP_ATOMIC);
861 if (!fa_cookie)
862 goto free_trap_name;
863 hw_metadata->fa_cookie = fa_cookie;
864 }
865
866 hw_metadata->input_dev = metadata->input_dev;
867 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker,
868 GFP_ATOMIC);
869
870 return hw_metadata;
871
872free_trap_name:
873 kfree(trap_name);
874free_trap_group:
875 kfree(trap_group_name);
876free_hw_metadata:
877 kfree(hw_metadata);
878 return NULL;
879}
880
881static void
882net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
883{
884 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker);
885 kfree(hw_metadata->fa_cookie);
886 kfree(hw_metadata->trap_name);
887 kfree(hw_metadata->trap_group_name);
888 kfree(hw_metadata);
889}
890
891static void net_dm_hw_packet_report(struct sk_buff *skb)
892{
893 struct devlink_trap_metadata *hw_metadata;
894 struct sk_buff *msg;
895 size_t payload_len;
896 int rc;
897
898 if (skb->data > skb_mac_header(skb))
899 skb_push(skb, skb->data - skb_mac_header(skb));
900 else
901 skb_pull(skb, skb_mac_header(skb) - skb->data);
902
903 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
904 if (net_dm_trunc_len)
905 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
906
907 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
908 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
909 GFP_KERNEL);
910 if (!msg)
911 goto out;
912
913 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
914 if (rc) {
915 nlmsg_free(msg);
916 goto out;
917 }
918
919 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
920
921out:
922 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
923 consume_skb(skb);
924}
925
926static void net_dm_hw_packet_work(struct work_struct *work)
927{
928 struct per_cpu_dm_data *hw_data;
929 struct sk_buff_head list;
930 struct sk_buff *skb;
931 unsigned long flags;
932
933 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
934
935 __skb_queue_head_init(&list);
936
937 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
938 skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
939 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
940
941 while ((skb = __skb_dequeue(&list)))
942 net_dm_hw_packet_report(skb);
943}
944
945static void
946net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
947 struct sk_buff *skb,
948 const struct devlink_trap_metadata *metadata)
949{
950 struct devlink_trap_metadata *n_hw_metadata;
951 ktime_t tstamp = ktime_get_real();
952 struct per_cpu_dm_data *hw_data;
953 struct sk_buff *nskb;
954 unsigned long flags;
955
956 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
957 return;
958
959 if (!skb_mac_header_was_set(skb))
960 return;
961
962 nskb = skb_clone(skb, GFP_ATOMIC);
963 if (!nskb)
964 return;
965
966 n_hw_metadata = net_dm_hw_metadata_copy(metadata);
967 if (!n_hw_metadata)
968 goto free;
969
970 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
971 nskb->tstamp = tstamp;
972
973 hw_data = this_cpu_ptr(&dm_hw_cpu_data);
974
975 spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
976 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
977 __skb_queue_tail(&hw_data->drop_queue, nskb);
978 else
979 goto unlock_free;
980 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
981
982 schedule_work(&hw_data->dm_alert_work);
983
984 return;
985
986unlock_free:
987 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
988 u64_stats_update_begin(&hw_data->stats.syncp);
989 u64_stats_inc(&hw_data->stats.dropped);
990 u64_stats_update_end(&hw_data->stats.syncp);
991 net_dm_hw_metadata_free(n_hw_metadata);
992free:
993 consume_skb(nskb);
994}
995
996static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
997 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit,
998 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit,
999 .work_item_func = net_dm_packet_work,
1000 .hw_work_item_func = net_dm_hw_packet_work,
1001 .hw_trap_probe = net_dm_hw_trap_packet_probe,
1002};
1003
1004static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1005 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops,
1006 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops,
1007};
1008
1009#if IS_ENABLED(CONFIG_NET_DEVLINK)
1010static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1011{
1012 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1013}
1014
1015static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1016{
1017 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1018 tracepoint_synchronize_unregister();
1019}
1020#else
1021static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1022{
1023 return -EOPNOTSUPP;
1024}
1025
1026static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1027{
1028}
1029#endif
1030
1031static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1032{
1033 const struct net_dm_alert_ops *ops;
1034 int cpu, rc;
1035
1036 if (monitor_hw) {
1037 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1038 return -EAGAIN;
1039 }
1040
1041 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1042
1043 if (!try_module_get(THIS_MODULE)) {
1044 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1045 return -ENODEV;
1046 }
1047
1048 for_each_possible_cpu(cpu) {
1049 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1050 struct net_dm_hw_entries *hw_entries;
1051
1052 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1053 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1054 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1055 kfree(hw_entries);
1056 }
1057
1058 rc = net_dm_hw_probe_register(ops);
1059 if (rc) {
1060 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1061 goto err_module_put;
1062 }
1063
1064 monitor_hw = true;
1065
1066 return 0;
1067
1068err_module_put:
1069 for_each_possible_cpu(cpu) {
1070 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1071 struct sk_buff *skb;
1072
1073 del_timer_sync(&hw_data->send_timer);
1074 cancel_work_sync(&hw_data->dm_alert_work);
1075 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1076 struct devlink_trap_metadata *hw_metadata;
1077
1078 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1079 net_dm_hw_metadata_free(hw_metadata);
1080 consume_skb(skb);
1081 }
1082 }
1083 module_put(THIS_MODULE);
1084 return rc;
1085}
1086
1087static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1088{
1089 const struct net_dm_alert_ops *ops;
1090 int cpu;
1091
1092 if (!monitor_hw) {
1093 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1094 return;
1095 }
1096
1097 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1098
1099 monitor_hw = false;
1100
1101 net_dm_hw_probe_unregister(ops);
1102
1103 for_each_possible_cpu(cpu) {
1104 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1105 struct sk_buff *skb;
1106
1107 del_timer_sync(&hw_data->send_timer);
1108 cancel_work_sync(&hw_data->dm_alert_work);
1109 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1110 struct devlink_trap_metadata *hw_metadata;
1111
1112 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1113 net_dm_hw_metadata_free(hw_metadata);
1114 consume_skb(skb);
1115 }
1116 }
1117
1118 module_put(THIS_MODULE);
1119}
1120
1121static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1122{
1123 const struct net_dm_alert_ops *ops;
1124 int cpu, rc;
1125
1126 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1127
1128 if (!try_module_get(THIS_MODULE)) {
1129 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1130 return -ENODEV;
1131 }
1132
1133 for_each_possible_cpu(cpu) {
1134 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1135 struct sk_buff *skb;
1136
1137 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1138 timer_setup(&data->send_timer, sched_send_work, 0);
1139 /* Allocate a new per-CPU skb for the summary alert message and
1140 * free the old one which might contain stale data from
1141 * previous tracing.
1142 */
1143 skb = reset_per_cpu_data(data);
1144 consume_skb(skb);
1145 }
1146
1147 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1148 if (rc) {
1149 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1150 goto err_module_put;
1151 }
1152
1153 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1154 if (rc) {
1155 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1156 goto err_unregister_trace;
1157 }
1158
1159 return 0;
1160
1161err_unregister_trace:
1162 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1163err_module_put:
1164 for_each_possible_cpu(cpu) {
1165 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1166 struct sk_buff *skb;
1167
1168 del_timer_sync(&data->send_timer);
1169 cancel_work_sync(&data->dm_alert_work);
1170 while ((skb = __skb_dequeue(&data->drop_queue)))
1171 consume_skb(skb);
1172 }
1173 module_put(THIS_MODULE);
1174 return rc;
1175}
1176
1177static void net_dm_trace_off_set(void)
1178{
1179 const struct net_dm_alert_ops *ops;
1180 int cpu;
1181
1182 ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1183
1184 unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1185 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1186
1187 tracepoint_synchronize_unregister();
1188
1189 /* Make sure we do not send notifications to user space after request
1190 * to stop tracing returns.
1191 */
1192 for_each_possible_cpu(cpu) {
1193 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1194 struct sk_buff *skb;
1195
1196 del_timer_sync(&data->send_timer);
1197 cancel_work_sync(&data->dm_alert_work);
1198 while ((skb = __skb_dequeue(&data->drop_queue)))
1199 consume_skb(skb);
1200 }
1201
1202 module_put(THIS_MODULE);
1203}
1204
1205static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1206{
1207 int rc = 0;
1208
1209 if (state == trace_state) {
1210 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1211 return -EAGAIN;
1212 }
1213
1214 switch (state) {
1215 case TRACE_ON:
1216 rc = net_dm_trace_on_set(extack);
1217 break;
1218 case TRACE_OFF:
1219 net_dm_trace_off_set();
1220 break;
1221 default:
1222 rc = 1;
1223 break;
1224 }
1225
1226 if (!rc)
1227 trace_state = state;
1228 else
1229 rc = -EINPROGRESS;
1230
1231 return rc;
1232}
1233
1234static bool net_dm_is_monitoring(void)
1235{
1236 return trace_state == TRACE_ON || monitor_hw;
1237}
1238
1239static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1240 enum net_dm_alert_mode *p_alert_mode)
1241{
1242 u8 val;
1243
1244 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1245
1246 switch (val) {
1247 case NET_DM_ALERT_MODE_SUMMARY:
1248 case NET_DM_ALERT_MODE_PACKET:
1249 *p_alert_mode = val;
1250 break;
1251 default:
1252 return -EINVAL;
1253 }
1254
1255 return 0;
1256}
1257
1258static int net_dm_alert_mode_set(struct genl_info *info)
1259{
1260 struct netlink_ext_ack *extack = info->extack;
1261 enum net_dm_alert_mode alert_mode;
1262 int rc;
1263
1264 if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1265 return 0;
1266
1267 rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1268 if (rc) {
1269 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1270 return -EINVAL;
1271 }
1272
1273 net_dm_alert_mode = alert_mode;
1274
1275 return 0;
1276}
1277
1278static void net_dm_trunc_len_set(struct genl_info *info)
1279{
1280 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1281 return;
1282
1283 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1284}
1285
1286static void net_dm_queue_len_set(struct genl_info *info)
1287{
1288 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1289 return;
1290
1291 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1292}
1293
1294static int net_dm_cmd_config(struct sk_buff *skb,
1295 struct genl_info *info)
1296{
1297 struct netlink_ext_ack *extack = info->extack;
1298 int rc;
1299
1300 if (net_dm_is_monitoring()) {
1301 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1302 return -EBUSY;
1303 }
1304
1305 rc = net_dm_alert_mode_set(info);
1306 if (rc)
1307 return rc;
1308
1309 net_dm_trunc_len_set(info);
1310
1311 net_dm_queue_len_set(info);
1312
1313 return 0;
1314}
1315
1316static int net_dm_monitor_start(bool set_sw, bool set_hw,
1317 struct netlink_ext_ack *extack)
1318{
1319 bool sw_set = false;
1320 int rc;
1321
1322 if (set_sw) {
1323 rc = set_all_monitor_traces(TRACE_ON, extack);
1324 if (rc)
1325 return rc;
1326 sw_set = true;
1327 }
1328
1329 if (set_hw) {
1330 rc = net_dm_hw_monitor_start(extack);
1331 if (rc)
1332 goto err_monitor_hw;
1333 }
1334
1335 return 0;
1336
1337err_monitor_hw:
1338 if (sw_set)
1339 set_all_monitor_traces(TRACE_OFF, extack);
1340 return rc;
1341}
1342
1343static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1344 struct netlink_ext_ack *extack)
1345{
1346 if (set_hw)
1347 net_dm_hw_monitor_stop(extack);
1348 if (set_sw)
1349 set_all_monitor_traces(TRACE_OFF, extack);
1350}
1351
1352static int net_dm_cmd_trace(struct sk_buff *skb,
1353 struct genl_info *info)
1354{
1355 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1356 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1357 struct netlink_ext_ack *extack = info->extack;
1358
1359 /* To maintain backward compatibility, we start / stop monitoring of
1360 * software drops if no flag is specified.
1361 */
1362 if (!set_sw && !set_hw)
1363 set_sw = true;
1364
1365 switch (info->genlhdr->cmd) {
1366 case NET_DM_CMD_START:
1367 return net_dm_monitor_start(set_sw, set_hw, extack);
1368 case NET_DM_CMD_STOP:
1369 net_dm_monitor_stop(set_sw, set_hw, extack);
1370 return 0;
1371 }
1372
1373 return -EOPNOTSUPP;
1374}
1375
1376static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1377{
1378 void *hdr;
1379
1380 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1381 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1382 if (!hdr)
1383 return -EMSGSIZE;
1384
1385 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1386 goto nla_put_failure;
1387
1388 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1389 goto nla_put_failure;
1390
1391 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1392 goto nla_put_failure;
1393
1394 genlmsg_end(msg, hdr);
1395
1396 return 0;
1397
1398nla_put_failure:
1399 genlmsg_cancel(msg, hdr);
1400 return -EMSGSIZE;
1401}
1402
1403static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1404{
1405 struct sk_buff *msg;
1406 int rc;
1407
1408 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1409 if (!msg)
1410 return -ENOMEM;
1411
1412 rc = net_dm_config_fill(msg, info);
1413 if (rc)
1414 goto free_msg;
1415
1416 return genlmsg_reply(msg, info);
1417
1418free_msg:
1419 nlmsg_free(msg);
1420 return rc;
1421}
1422
1423static void net_dm_stats_read(struct net_dm_stats *stats)
1424{
1425 int cpu;
1426
1427 memset(stats, 0, sizeof(*stats));
1428 for_each_possible_cpu(cpu) {
1429 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1430 struct net_dm_stats *cpu_stats = &data->stats;
1431 unsigned int start;
1432 u64 dropped;
1433
1434 do {
1435 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1436 dropped = u64_stats_read(&cpu_stats->dropped);
1437 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1438
1439 u64_stats_add(&stats->dropped, dropped);
1440 }
1441}
1442
1443static int net_dm_stats_put(struct sk_buff *msg)
1444{
1445 struct net_dm_stats stats;
1446 struct nlattr *attr;
1447
1448 net_dm_stats_read(&stats);
1449
1450 attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1451 if (!attr)
1452 return -EMSGSIZE;
1453
1454 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1455 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1456 goto nla_put_failure;
1457
1458 nla_nest_end(msg, attr);
1459
1460 return 0;
1461
1462nla_put_failure:
1463 nla_nest_cancel(msg, attr);
1464 return -EMSGSIZE;
1465}
1466
1467static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1468{
1469 int cpu;
1470
1471 memset(stats, 0, sizeof(*stats));
1472 for_each_possible_cpu(cpu) {
1473 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1474 struct net_dm_stats *cpu_stats = &hw_data->stats;
1475 unsigned int start;
1476 u64 dropped;
1477
1478 do {
1479 start = u64_stats_fetch_begin(&cpu_stats->syncp);
1480 dropped = u64_stats_read(&cpu_stats->dropped);
1481 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1482
1483 u64_stats_add(&stats->dropped, dropped);
1484 }
1485}
1486
1487static int net_dm_hw_stats_put(struct sk_buff *msg)
1488{
1489 struct net_dm_stats stats;
1490 struct nlattr *attr;
1491
1492 net_dm_hw_stats_read(&stats);
1493
1494 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1495 if (!attr)
1496 return -EMSGSIZE;
1497
1498 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1499 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1500 goto nla_put_failure;
1501
1502 nla_nest_end(msg, attr);
1503
1504 return 0;
1505
1506nla_put_failure:
1507 nla_nest_cancel(msg, attr);
1508 return -EMSGSIZE;
1509}
1510
1511static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1512{
1513 void *hdr;
1514 int rc;
1515
1516 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1517 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1518 if (!hdr)
1519 return -EMSGSIZE;
1520
1521 rc = net_dm_stats_put(msg);
1522 if (rc)
1523 goto nla_put_failure;
1524
1525 rc = net_dm_hw_stats_put(msg);
1526 if (rc)
1527 goto nla_put_failure;
1528
1529 genlmsg_end(msg, hdr);
1530
1531 return 0;
1532
1533nla_put_failure:
1534 genlmsg_cancel(msg, hdr);
1535 return -EMSGSIZE;
1536}
1537
1538static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1539{
1540 struct sk_buff *msg;
1541 int rc;
1542
1543 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1544 if (!msg)
1545 return -ENOMEM;
1546
1547 rc = net_dm_stats_fill(msg, info);
1548 if (rc)
1549 goto free_msg;
1550
1551 return genlmsg_reply(msg, info);
1552
1553free_msg:
1554 nlmsg_free(msg);
1555 return rc;
1556}
1557
1558static int dropmon_net_event(struct notifier_block *ev_block,
1559 unsigned long event, void *ptr)
1560{
1561 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1562 struct dm_hw_stat_delta *stat;
1563
1564 switch (event) {
1565 case NETDEV_REGISTER:
1566 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1567 break;
1568 stat = kzalloc(sizeof(*stat), GFP_KERNEL);
1569 if (!stat)
1570 break;
1571
1572 stat->last_rx = jiffies;
1573 rcu_assign_pointer(dev->dm_private, stat);
1574
1575 break;
1576 case NETDEV_UNREGISTER:
1577 stat = rtnl_dereference(dev->dm_private);
1578 if (stat) {
1579 rcu_assign_pointer(dev->dm_private, NULL);
1580 kfree_rcu(stat, rcu);
1581 }
1582 break;
1583 }
1584 return NOTIFY_DONE;
1585}
1586
1587static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1588 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1589 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1590 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1591 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1592 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG },
1593 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG },
1594};
1595
1596static const struct genl_small_ops dropmon_ops[] = {
1597 {
1598 .cmd = NET_DM_CMD_CONFIG,
1599 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1600 .doit = net_dm_cmd_config,
1601 .flags = GENL_ADMIN_PERM,
1602 },
1603 {
1604 .cmd = NET_DM_CMD_START,
1605 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1606 .doit = net_dm_cmd_trace,
1607 },
1608 {
1609 .cmd = NET_DM_CMD_STOP,
1610 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1611 .doit = net_dm_cmd_trace,
1612 },
1613 {
1614 .cmd = NET_DM_CMD_CONFIG_GET,
1615 .doit = net_dm_cmd_config_get,
1616 },
1617 {
1618 .cmd = NET_DM_CMD_STATS_GET,
1619 .doit = net_dm_cmd_stats_get,
1620 },
1621};
1622
1623static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
1624 struct sk_buff *skb, struct genl_info *info)
1625{
1626 mutex_lock(&net_dm_mutex);
1627
1628 return 0;
1629}
1630
1631static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
1632 struct sk_buff *skb, struct genl_info *info)
1633{
1634 mutex_unlock(&net_dm_mutex);
1635}
1636
1637static struct genl_family net_drop_monitor_family __ro_after_init = {
1638 .hdrsize = 0,
1639 .name = "NET_DM",
1640 .version = 2,
1641 .maxattr = NET_DM_ATTR_MAX,
1642 .policy = net_dm_nl_policy,
1643 .pre_doit = net_dm_nl_pre_doit,
1644 .post_doit = net_dm_nl_post_doit,
1645 .module = THIS_MODULE,
1646 .small_ops = dropmon_ops,
1647 .n_small_ops = ARRAY_SIZE(dropmon_ops),
1648 .resv_start_op = NET_DM_CMD_STATS_GET + 1,
1649 .mcgrps = dropmon_mcgrps,
1650 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps),
1651};
1652
1653static struct notifier_block dropmon_net_notifier = {
1654 .notifier_call = dropmon_net_event
1655};
1656
1657static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1658{
1659 spin_lock_init(&data->lock);
1660 skb_queue_head_init(&data->drop_queue);
1661 u64_stats_init(&data->stats.syncp);
1662}
1663
1664static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1665{
1666 WARN_ON(!skb_queue_empty(&data->drop_queue));
1667}
1668
1669static void net_dm_cpu_data_init(int cpu)
1670{
1671 struct per_cpu_dm_data *data;
1672
1673 data = &per_cpu(dm_cpu_data, cpu);
1674 __net_dm_cpu_data_init(data);
1675}
1676
1677static void net_dm_cpu_data_fini(int cpu)
1678{
1679 struct per_cpu_dm_data *data;
1680
1681 data = &per_cpu(dm_cpu_data, cpu);
1682 /* At this point, we should have exclusive access
1683 * to this struct and can free the skb inside it.
1684 */
1685 consume_skb(data->skb);
1686 __net_dm_cpu_data_fini(data);
1687}
1688
1689static void net_dm_hw_cpu_data_init(int cpu)
1690{
1691 struct per_cpu_dm_data *hw_data;
1692
1693 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1694 __net_dm_cpu_data_init(hw_data);
1695}
1696
1697static void net_dm_hw_cpu_data_fini(int cpu)
1698{
1699 struct per_cpu_dm_data *hw_data;
1700
1701 hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1702 kfree(hw_data->hw_entries);
1703 __net_dm_cpu_data_fini(hw_data);
1704}
1705
1706static int __init init_net_drop_monitor(void)
1707{
1708 int cpu, rc;
1709
1710 pr_info("Initializing network drop monitor service\n");
1711
1712 if (sizeof(void *) > 8) {
1713 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1714 return -ENOSPC;
1715 }
1716
1717 rc = genl_register_family(&net_drop_monitor_family);
1718 if (rc) {
1719 pr_err("Could not create drop monitor netlink family\n");
1720 return rc;
1721 }
1722 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1723
1724 rc = register_netdevice_notifier(&dropmon_net_notifier);
1725 if (rc < 0) {
1726 pr_crit("Failed to register netdevice notifier\n");
1727 goto out_unreg;
1728 }
1729
1730 rc = 0;
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 goto out;
1738
1739out_unreg:
1740 genl_unregister_family(&net_drop_monitor_family);
1741out:
1742 return rc;
1743}
1744
1745static void exit_net_drop_monitor(void)
1746{
1747 int cpu;
1748
1749 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1750
1751 /*
1752 * Because of the module_get/put we do in the trace state change path
1753 * we are guaranteed not to have any current users when we get here
1754 */
1755
1756 for_each_possible_cpu(cpu) {
1757 net_dm_hw_cpu_data_fini(cpu);
1758 net_dm_cpu_data_fini(cpu);
1759 }
1760
1761 BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1762}
1763
1764module_init(init_net_drop_monitor);
1765module_exit(exit_net_drop_monitor);
1766
1767MODULE_LICENSE("GPL v2");
1768MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1769MODULE_ALIAS_GENL_FAMILY("NET_DM");
1770MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");