Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
[cris-mirror.git] / net / core / drop_monitor.c
blob706502ff64aa884548bf5122bd71085aea098a45
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(void *ignore, struct sk_buff *skb, void *location)
177 trace_drop_common(skb, location);
180 static void trace_napi_poll_hit(void *ignore, 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 if (state == trace_state) {
227 rc = -EAGAIN;
228 goto out_unlock;
231 switch (state) {
232 case TRACE_ON:
233 rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL);
234 rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL);
235 break;
236 case TRACE_OFF:
237 rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL);
238 rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL);
240 tracepoint_synchronize_unregister();
243 * Clean the device list
245 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
246 if (new_stat->dev == NULL) {
247 list_del_rcu(&new_stat->list);
248 call_rcu(&new_stat->rcu, free_dm_hw_stat);
251 break;
252 default:
253 rc = 1;
254 break;
257 if (!rc)
258 trace_state = state;
259 else
260 rc = -EINPROGRESS;
262 out_unlock:
263 spin_unlock(&trace_state_lock);
265 return rc;
269 static int net_dm_cmd_config(struct sk_buff *skb,
270 struct genl_info *info)
272 return -ENOTSUPP;
275 static int net_dm_cmd_trace(struct sk_buff *skb,
276 struct genl_info *info)
278 switch (info->genlhdr->cmd) {
279 case NET_DM_CMD_START:
280 return set_all_monitor_traces(TRACE_ON);
281 break;
282 case NET_DM_CMD_STOP:
283 return set_all_monitor_traces(TRACE_OFF);
284 break;
287 return -ENOTSUPP;
290 static int dropmon_net_event(struct notifier_block *ev_block,
291 unsigned long event, void *ptr)
293 struct net_device *dev = ptr;
294 struct dm_hw_stat_delta *new_stat = NULL;
295 struct dm_hw_stat_delta *tmp;
297 switch (event) {
298 case NETDEV_REGISTER:
299 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
301 if (!new_stat)
302 goto out;
304 new_stat->dev = dev;
305 new_stat->last_rx = jiffies;
306 spin_lock(&trace_state_lock);
307 list_add_rcu(&new_stat->list, &hw_stats_list);
308 spin_unlock(&trace_state_lock);
309 break;
310 case NETDEV_UNREGISTER:
311 spin_lock(&trace_state_lock);
312 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
313 if (new_stat->dev == dev) {
314 new_stat->dev = NULL;
315 if (trace_state == TRACE_OFF) {
316 list_del_rcu(&new_stat->list);
317 call_rcu(&new_stat->rcu, free_dm_hw_stat);
318 break;
322 spin_unlock(&trace_state_lock);
323 break;
325 out:
326 return NOTIFY_DONE;
329 static struct genl_ops dropmon_ops[] = {
331 .cmd = NET_DM_CMD_CONFIG,
332 .doit = net_dm_cmd_config,
335 .cmd = NET_DM_CMD_START,
336 .doit = net_dm_cmd_trace,
339 .cmd = NET_DM_CMD_STOP,
340 .doit = net_dm_cmd_trace,
344 static struct notifier_block dropmon_net_notifier = {
345 .notifier_call = dropmon_net_event
348 static int __init init_net_drop_monitor(void)
350 struct per_cpu_dm_data *data;
351 int cpu, rc;
353 printk(KERN_INFO "Initializing network drop monitor service\n");
355 if (sizeof(void *) > 8) {
356 printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n");
357 return -ENOSPC;
360 rc = genl_register_family_with_ops(&net_drop_monitor_family,
361 dropmon_ops,
362 ARRAY_SIZE(dropmon_ops));
363 if (rc) {
364 printk(KERN_ERR "Could not create drop monitor netlink family\n");
365 return rc;
368 rc = register_netdevice_notifier(&dropmon_net_notifier);
369 if (rc < 0) {
370 printk(KERN_CRIT "Failed to register netdevice notifier\n");
371 goto out_unreg;
374 rc = 0;
376 for_each_present_cpu(cpu) {
377 data = &per_cpu(dm_cpu_data, cpu);
378 reset_per_cpu_data(data);
379 INIT_WORK(&data->dm_alert_work, send_dm_alert);
380 init_timer(&data->send_timer);
381 data->send_timer.data = cpu;
382 data->send_timer.function = sched_send_work;
385 goto out;
387 out_unreg:
388 genl_unregister_family(&net_drop_monitor_family);
389 out:
390 return rc;
393 late_initcall(init_net_drop_monitor);