Merge branch 'misc-2.6.33' into release
[linux-2.6-block.git] / net / core / drop_monitor.c
CommitLineData
9a8afc8d
NH
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 <net/genetlink.h>
4ea7e386 25#include <net/netevent.h>
9a8afc8d 26
ad8d75ff 27#include <trace/events/skb.h>
9cbc1cb8 28#include <trace/events/napi.h>
9a8afc8d
NH
29
30#include <asm/unaligned.h>
31
32#define TRACE_ON 1
33#define TRACE_OFF 0
34
35static void send_dm_alert(struct work_struct *unused);
36
37
38/*
39 * Globals, our netlink socket pointer
40 * and the work handle that will send up
41 * netlink alerts
42 */
4ea7e386 43static int trace_state = TRACE_OFF;
d3bcfefa 44static DEFINE_SPINLOCK(trace_state_lock);
9a8afc8d
NH
45
46struct per_cpu_dm_data {
47 struct work_struct dm_alert_work;
48 struct sk_buff *skb;
49 atomic_t dm_hit_count;
50 struct timer_list send_timer;
51};
52
4ea7e386
NH
53struct dm_hw_stat_delta {
54 struct net_device *dev;
5848cc09 55 unsigned long last_rx;
4ea7e386
NH
56 struct list_head list;
57 struct rcu_head rcu;
58 unsigned long last_drop_val;
59};
60
9a8afc8d
NH
61static struct genl_family net_drop_monitor_family = {
62 .id = GENL_ID_GENERATE,
63 .hdrsize = 0,
64 .name = "NET_DM",
683703a2 65 .version = 2,
9a8afc8d
NH
66 .maxattr = NET_DM_CMD_MAX,
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;
4ea7e386
NH
73static unsigned long dm_hw_check_delta = 2*HZ;
74static LIST_HEAD(hw_stats_list);
9a8afc8d
NH
75
76static void reset_per_cpu_data(struct per_cpu_dm_data *data)
77{
78 size_t al;
79 struct net_dm_alert_msg *msg;
683703a2 80 struct nlattr *nla;
9a8afc8d
NH
81
82 al = sizeof(struct net_dm_alert_msg);
83 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
683703a2
NH
84 al += sizeof(struct nlattr);
85
9a8afc8d
NH
86 data->skb = genlmsg_new(al, GFP_KERNEL);
87 genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family,
88 0, NET_DM_CMD_ALERT);
683703a2
NH
89 nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg));
90 msg = nla_data(nla);
9a8afc8d
NH
91 memset(msg, 0, al);
92 atomic_set(&data->dm_hit_count, dm_hit_limit);
93}
94
95static void send_dm_alert(struct work_struct *unused)
96{
97 struct sk_buff *skb;
98 struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
99
100 /*
101 * Grab the skb we're about to send
102 */
103 skb = data->skb;
104
105 /*
106 * Replace it with a new one
107 */
108 reset_per_cpu_data(data);
109
110 /*
111 * Ship it!
112 */
113 genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
114
115}
116
117/*
118 * This is the timer function to delay the sending of an alert
119 * in the event that more drops will arrive during the
120 * hysteresis period. Note that it operates under the timer interrupt
121 * so we don't need to disable preemption here
122 */
123static void sched_send_work(unsigned long unused)
124{
125 struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
126
127 schedule_work(&data->dm_alert_work);
128}
129
4ea7e386 130static void trace_drop_common(struct sk_buff *skb, void *location)
9a8afc8d
NH
131{
132 struct net_dm_alert_msg *msg;
133 struct nlmsghdr *nlh;
683703a2 134 struct nlattr *nla;
9a8afc8d
NH
135 int i;
136 struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
137
138
139 if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
140 /*
141 * we're already at zero, discard this hit
142 */
143 goto out;
144 }
145
146 nlh = (struct nlmsghdr *)data->skb->data;
683703a2
NH
147 nla = genlmsg_data(nlmsg_data(nlh));
148 msg = nla_data(nla);
9a8afc8d
NH
149 for (i = 0; i < msg->entries; i++) {
150 if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
151 msg->points[i].count++;
152 goto out;
153 }
154 }
155
156 /*
157 * We need to create a new entry
158 */
159 __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point));
683703a2 160 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
9a8afc8d
NH
161 memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
162 msg->points[msg->entries].count = 1;
163 msg->entries++;
164
165 if (!timer_pending(&data->send_timer)) {
166 data->send_timer.expires = jiffies + dm_delay * HZ;
167 add_timer_on(&data->send_timer, smp_processor_id());
168 }
169
170out:
171 return;
172}
173
4ea7e386
NH
174static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
175{
176 trace_drop_common(skb, location);
177}
178
179static void trace_napi_poll_hit(struct napi_struct *napi)
180{
181 struct dm_hw_stat_delta *new_stat;
182
183 /*
5848cc09 184 * Don't check napi structures with no associated device
4ea7e386 185 */
5848cc09 186 if (!napi->dev)
4ea7e386
NH
187 return;
188
189 rcu_read_lock();
190 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
5848cc09
NH
191 /*
192 * only add a note to our monitor buffer if:
193 * 1) this is the dev we received on
194 * 2) its after the last_rx delta
195 * 3) our rx_dropped count has gone up
196 */
4ea7e386 197 if ((new_stat->dev == napi->dev) &&
5848cc09 198 (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
4ea7e386
NH
199 (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
200 trace_drop_common(NULL, NULL);
201 new_stat->last_drop_val = napi->dev->stats.rx_dropped;
5848cc09 202 new_stat->last_rx = jiffies;
4ea7e386
NH
203 break;
204 }
205 }
206 rcu_read_unlock();
207}
208
209
210static void free_dm_hw_stat(struct rcu_head *head)
211{
212 struct dm_hw_stat_delta *n;
213 n = container_of(head, struct dm_hw_stat_delta, rcu);
214 kfree(n);
215}
216
9a8afc8d
NH
217static int set_all_monitor_traces(int state)
218{
219 int rc = 0;
4ea7e386
NH
220 struct dm_hw_stat_delta *new_stat = NULL;
221 struct dm_hw_stat_delta *temp;
222
223 spin_lock(&trace_state_lock);
9a8afc8d
NH
224
225 switch (state) {
226 case TRACE_ON:
227 rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
4ea7e386 228 rc |= register_trace_napi_poll(trace_napi_poll_hit);
9a8afc8d
NH
229 break;
230 case TRACE_OFF:
231 rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
4ea7e386 232 rc |= unregister_trace_napi_poll(trace_napi_poll_hit);
9a8afc8d
NH
233
234 tracepoint_synchronize_unregister();
4ea7e386
NH
235
236 /*
237 * Clean the device list
238 */
239 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
240 if (new_stat->dev == NULL) {
241 list_del_rcu(&new_stat->list);
242 call_rcu(&new_stat->rcu, free_dm_hw_stat);
243 }
244 }
9a8afc8d
NH
245 break;
246 default:
247 rc = 1;
248 break;
249 }
250
4ea7e386
NH
251 if (!rc)
252 trace_state = state;
253
254 spin_unlock(&trace_state_lock);
255
9a8afc8d
NH
256 if (rc)
257 return -EINPROGRESS;
258 return rc;
259}
260
261
262static int net_dm_cmd_config(struct sk_buff *skb,
263 struct genl_info *info)
264{
265 return -ENOTSUPP;
266}
267
268static int net_dm_cmd_trace(struct sk_buff *skb,
269 struct genl_info *info)
270{
271 switch (info->genlhdr->cmd) {
272 case NET_DM_CMD_START:
273 return set_all_monitor_traces(TRACE_ON);
274 break;
275 case NET_DM_CMD_STOP:
276 return set_all_monitor_traces(TRACE_OFF);
277 break;
278 }
279
280 return -ENOTSUPP;
281}
282
4ea7e386
NH
283static int dropmon_net_event(struct notifier_block *ev_block,
284 unsigned long event, void *ptr)
285{
286 struct net_device *dev = ptr;
287 struct dm_hw_stat_delta *new_stat = NULL;
288 struct dm_hw_stat_delta *tmp;
289
290 switch (event) {
291 case NETDEV_REGISTER:
292 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
293
294 if (!new_stat)
295 goto out;
296
297 new_stat->dev = dev;
5848cc09 298 new_stat->last_rx = jiffies;
4ea7e386
NH
299 INIT_RCU_HEAD(&new_stat->rcu);
300 spin_lock(&trace_state_lock);
301 list_add_rcu(&new_stat->list, &hw_stats_list);
302 spin_unlock(&trace_state_lock);
303 break;
304 case NETDEV_UNREGISTER:
305 spin_lock(&trace_state_lock);
306 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
307 if (new_stat->dev == dev) {
308 new_stat->dev = NULL;
309 if (trace_state == TRACE_OFF) {
310 list_del_rcu(&new_stat->list);
311 call_rcu(&new_stat->rcu, free_dm_hw_stat);
312 break;
313 }
314 }
315 }
316 spin_unlock(&trace_state_lock);
317 break;
318 }
319out:
320 return NOTIFY_DONE;
321}
9a8afc8d
NH
322
323static struct genl_ops dropmon_ops[] = {
324 {
325 .cmd = NET_DM_CMD_CONFIG,
326 .doit = net_dm_cmd_config,
327 },
328 {
329 .cmd = NET_DM_CMD_START,
330 .doit = net_dm_cmd_trace,
331 },
332 {
333 .cmd = NET_DM_CMD_STOP,
334 .doit = net_dm_cmd_trace,
335 },
336};
337
4ea7e386
NH
338static struct notifier_block dropmon_net_notifier = {
339 .notifier_call = dropmon_net_event
340};
341
9a8afc8d
NH
342static int __init init_net_drop_monitor(void)
343{
344 int cpu;
345 int rc, i, ret;
346 struct per_cpu_dm_data *data;
347 printk(KERN_INFO "Initalizing network drop monitor service\n");
348
349 if (sizeof(void *) > 8) {
350 printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
351 return -ENOSPC;
352 }
353
354 if (genl_register_family(&net_drop_monitor_family) < 0) {
355 printk(KERN_ERR "Could not create drop monitor netlink family\n");
356 return -EFAULT;
357 }
358
359 rc = -EFAULT;
360
361 for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) {
362 ret = genl_register_ops(&net_drop_monitor_family,
363 &dropmon_ops[i]);
364 if (ret) {
4ea7e386 365 printk(KERN_CRIT "Failed to register operation %d\n",
9a8afc8d
NH
366 dropmon_ops[i].cmd);
367 goto out_unreg;
368 }
369 }
370
4ea7e386
NH
371 rc = register_netdevice_notifier(&dropmon_net_notifier);
372 if (rc < 0) {
373 printk(KERN_CRIT "Failed to register netdevice notifier\n");
374 goto out_unreg;
375 }
376
9a8afc8d
NH
377 rc = 0;
378
379 for_each_present_cpu(cpu) {
380 data = &per_cpu(dm_cpu_data, cpu);
381 reset_per_cpu_data(data);
382 INIT_WORK(&data->dm_alert_work, send_dm_alert);
383 init_timer(&data->send_timer);
384 data->send_timer.data = cpu;
385 data->send_timer.function = sched_send_work;
386 }
4ea7e386 387
9a8afc8d
NH
388 goto out;
389
390out_unreg:
391 genl_unregister_family(&net_drop_monitor_family);
392out:
393 return rc;
394}
395
396late_initcall(init_net_drop_monitor);