Merge branch 'timers-for-linus-hpet' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / core / drop_monitor.c
blobcf208d8042b198d962a8ccfbd81c0b70acca28c2
1 /*
2 * Monitoring code for network dropped packet alerts
4 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
5 */
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>
28 #include <trace/events/skb.h>
29 #include <trace/events/napi.h>
31 #include <asm/unaligned.h>
33 #define TRACE_ON 1
34 #define TRACE_OFF 0
36 static void send_dm_alert(struct work_struct *unused);
40 * Globals, our netlink socket pointer
41 * and the work handle that will send up
42 * netlink alerts
44 static int trace_state = TRACE_OFF;
45 static DEFINE_SPINLOCK(trace_state_lock);
47 struct 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;
54 struct 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;
62 static 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,
70 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
72 static int dm_hit_limit = 64;
73 static int dm_delay = 1;
74 static unsigned long dm_hw_check_delta = 2*HZ;
75 static LIST_HEAD(hw_stats_list);
77 static void reset_per_cpu_data(struct per_cpu_dm_data *data)
79 size_t al;
80 struct net_dm_alert_msg *msg;
81 struct nlattr *nla;
83 al = sizeof(struct net_dm_alert_msg);
84 al += dm_hit_limit * sizeof(struct net_dm_drop_point);
85 al += sizeof(struct nlattr);
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);
96 static void send_dm_alert(struct work_struct *unused)
98 struct sk_buff *skb;
99 struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
102 * Grab the skb we're about to send
104 skb = data->skb;
107 * Replace it with a new one
109 reset_per_cpu_data(data);
112 * Ship it!
114 genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL);
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
124 static void sched_send_work(unsigned long unused)
126 struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data);
128 schedule_work(&data->dm_alert_work);
131 static void trace_drop_common(struct sk_buff *skb, void *location)
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);
140 if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) {
142 * we're already at zero, discard this hit
144 goto out;
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;
158 * We need to create a new entry
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++;
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());
171 out:
172 return;
175 static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
177 trace_drop_common(skb, location);
180 static void trace_napi_poll_hit(struct napi_struct *napi)
182 struct dm_hw_stat_delta *new_stat;
185 * Don't check napi structures with no associated device
187 if (!napi->dev)
188 return;
190 rcu_read_lock();
191 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
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
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;
207 rcu_read_unlock();
211 static void free_dm_hw_stat(struct rcu_head *head)
213 struct dm_hw_stat_delta *n;
214 n = container_of(head, struct dm_hw_stat_delta, rcu);
215 kfree(n);
218 static int set_all_monitor_traces(int state)
220 int rc = 0;
221 struct dm_hw_stat_delta *new_stat = NULL;
222 struct dm_hw_stat_delta *temp;
224 spin_lock(&trace_state_lock);
226 switch (state) {
227 case TRACE_ON:
228 rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
229 rc |= register_trace_napi_poll(trace_napi_poll_hit);
230 break;
231 case TRACE_OFF:
232 rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
233 rc |= unregister_trace_napi_poll(trace_napi_poll_hit);
235 tracepoint_synchronize_unregister();
238 * Clean the device list
240 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
241 if (new_stat->dev == NULL) {
242 list_del_rcu(&new_stat->list);
243 call_rcu(&new_stat->rcu, free_dm_hw_stat);
246 break;
247 default:
248 rc = 1;
249 break;
252 if (!rc)
253 trace_state = state;
255 spin_unlock(&trace_state_lock);
257 if (rc)
258 return -EINPROGRESS;
259 return rc;
263 static int net_dm_cmd_config(struct sk_buff *skb,
264 struct genl_info *info)
266 return -ENOTSUPP;
269 static int net_dm_cmd_trace(struct sk_buff *skb,
270 struct genl_info *info)
272 switch (info->genlhdr->cmd) {
273 case NET_DM_CMD_START:
274 return set_all_monitor_traces(TRACE_ON);
275 break;
276 case NET_DM_CMD_STOP:
277 return set_all_monitor_traces(TRACE_OFF);
278 break;
281 return -ENOTSUPP;
284 static int dropmon_net_event(struct notifier_block *ev_block,
285 unsigned long event, void *ptr)
287 struct net_device *dev = ptr;
288 struct dm_hw_stat_delta *new_stat = NULL;
289 struct dm_hw_stat_delta *tmp;
291 switch (event) {
292 case NETDEV_REGISTER:
293 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
295 if (!new_stat)
296 goto out;
298 new_stat->dev = dev;
299 new_stat->last_rx = jiffies;
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;
316 spin_unlock(&trace_state_lock);
317 break;
319 out:
320 return NOTIFY_DONE;
323 static struct genl_ops dropmon_ops[] = {
325 .cmd = NET_DM_CMD_CONFIG,
326 .doit = net_dm_cmd_config,
329 .cmd = NET_DM_CMD_START,
330 .doit = net_dm_cmd_trace,
333 .cmd = NET_DM_CMD_STOP,
334 .doit = net_dm_cmd_trace,
338 static struct notifier_block dropmon_net_notifier = {
339 .notifier_call = dropmon_net_event
342 static int __init init_net_drop_monitor(void)
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");
349 if (sizeof(void *) > 8) {
350 printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
351 return -ENOSPC;
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;
359 rc = -EFAULT;
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) {
365 printk(KERN_CRIT "Failed to register operation %d\n",
366 dropmon_ops[i].cmd);
367 goto out_unreg;
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;
377 rc = 0;
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;
388 goto out;
390 out_unreg:
391 genl_unregister_family(&net_drop_monitor_family);
392 out:
393 return rc;
396 late_initcall(init_net_drop_monitor);