2 * Monitoring code for network dropped packet alerts
4 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
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>
25 #include <net/netevent.h>
27 #include <trace/events/skb.h>
28 #include <trace/events/napi.h>
30 #include <asm/unaligned.h>
35 static void send_dm_alert(struct work_struct
*unused
);
39 * Globals, our netlink socket pointer
40 * and the work handle that will send up
43 static int trace_state
= TRACE_OFF
;
44 static spinlock_t trace_state_lock
= SPIN_LOCK_UNLOCKED
;
46 struct per_cpu_dm_data
{
47 struct work_struct dm_alert_work
;
49 atomic_t dm_hit_count
;
50 struct timer_list send_timer
;
53 struct dm_hw_stat_delta
{
54 struct net_device
*dev
;
55 struct list_head list
;
57 unsigned long last_drop_val
;
60 static struct genl_family net_drop_monitor_family
= {
61 .id
= GENL_ID_GENERATE
,
65 .maxattr
= NET_DM_CMD_MAX
,
68 static DEFINE_PER_CPU(struct per_cpu_dm_data
, dm_cpu_data
);
70 static int dm_hit_limit
= 64;
71 static int dm_delay
= 1;
72 static unsigned long dm_hw_check_delta
= 2*HZ
;
73 static LIST_HEAD(hw_stats_list
);
75 static void reset_per_cpu_data(struct per_cpu_dm_data
*data
)
78 struct net_dm_alert_msg
*msg
;
81 al
= sizeof(struct net_dm_alert_msg
);
82 al
+= dm_hit_limit
* sizeof(struct net_dm_drop_point
);
83 al
+= sizeof(struct nlattr
);
85 data
->skb
= genlmsg_new(al
, GFP_KERNEL
);
86 genlmsg_put(data
->skb
, 0, 0, &net_drop_monitor_family
,
88 nla
= nla_reserve(data
->skb
, NLA_UNSPEC
, sizeof(struct net_dm_alert_msg
));
91 atomic_set(&data
->dm_hit_count
, dm_hit_limit
);
94 static void send_dm_alert(struct work_struct
*unused
)
97 struct per_cpu_dm_data
*data
= &__get_cpu_var(dm_cpu_data
);
100 * Grab the skb we're about to send
105 * Replace it with a new one
107 reset_per_cpu_data(data
);
112 genlmsg_multicast(skb
, 0, NET_DM_GRP_ALERT
, GFP_KERNEL
);
117 * This is the timer function to delay the sending of an alert
118 * in the event that more drops will arrive during the
119 * hysteresis period. Note that it operates under the timer interrupt
120 * so we don't need to disable preemption here
122 static void sched_send_work(unsigned long unused
)
124 struct per_cpu_dm_data
*data
= &__get_cpu_var(dm_cpu_data
);
126 schedule_work(&data
->dm_alert_work
);
129 static void trace_drop_common(struct sk_buff
*skb
, void *location
)
131 struct net_dm_alert_msg
*msg
;
132 struct nlmsghdr
*nlh
;
135 struct per_cpu_dm_data
*data
= &__get_cpu_var(dm_cpu_data
);
138 if (!atomic_add_unless(&data
->dm_hit_count
, -1, 0)) {
140 * we're already at zero, discard this hit
145 nlh
= (struct nlmsghdr
*)data
->skb
->data
;
146 nla
= genlmsg_data(nlmsg_data(nlh
));
148 for (i
= 0; i
< msg
->entries
; i
++) {
149 if (!memcmp(&location
, msg
->points
[i
].pc
, sizeof(void *))) {
150 msg
->points
[i
].count
++;
156 * We need to create a new entry
158 __nla_reserve_nohdr(data
->skb
, sizeof(struct net_dm_drop_point
));
159 nla
->nla_len
+= NLA_ALIGN(sizeof(struct net_dm_drop_point
));
160 memcpy(msg
->points
[msg
->entries
].pc
, &location
, sizeof(void *));
161 msg
->points
[msg
->entries
].count
= 1;
164 if (!timer_pending(&data
->send_timer
)) {
165 data
->send_timer
.expires
= jiffies
+ dm_delay
* HZ
;
166 add_timer_on(&data
->send_timer
, smp_processor_id());
173 static void trace_kfree_skb_hit(struct sk_buff
*skb
, void *location
)
175 trace_drop_common(skb
, location
);
178 static void trace_napi_poll_hit(struct napi_struct
*napi
)
180 struct dm_hw_stat_delta
*new_stat
;
183 * Ratelimit our check time to dm_hw_check_delta jiffies
186 !time_after(jiffies
, napi
->dev
->last_rx
+ dm_hw_check_delta
))
190 list_for_each_entry_rcu(new_stat
, &hw_stats_list
, list
) {
191 if ((new_stat
->dev
== napi
->dev
) &&
192 (napi
->dev
->stats
.rx_dropped
!= new_stat
->last_drop_val
)) {
193 trace_drop_common(NULL
, NULL
);
194 new_stat
->last_drop_val
= napi
->dev
->stats
.rx_dropped
;
202 static void free_dm_hw_stat(struct rcu_head
*head
)
204 struct dm_hw_stat_delta
*n
;
205 n
= container_of(head
, struct dm_hw_stat_delta
, rcu
);
209 static int set_all_monitor_traces(int state
)
212 struct dm_hw_stat_delta
*new_stat
= NULL
;
213 struct dm_hw_stat_delta
*temp
;
215 spin_lock(&trace_state_lock
);
219 rc
|= register_trace_kfree_skb(trace_kfree_skb_hit
);
220 rc
|= register_trace_napi_poll(trace_napi_poll_hit
);
223 rc
|= unregister_trace_kfree_skb(trace_kfree_skb_hit
);
224 rc
|= unregister_trace_napi_poll(trace_napi_poll_hit
);
226 tracepoint_synchronize_unregister();
229 * Clean the device list
231 list_for_each_entry_safe(new_stat
, temp
, &hw_stats_list
, list
) {
232 if (new_stat
->dev
== NULL
) {
233 list_del_rcu(&new_stat
->list
);
234 call_rcu(&new_stat
->rcu
, free_dm_hw_stat
);
246 spin_unlock(&trace_state_lock
);
254 static int net_dm_cmd_config(struct sk_buff
*skb
,
255 struct genl_info
*info
)
260 static int net_dm_cmd_trace(struct sk_buff
*skb
,
261 struct genl_info
*info
)
263 switch (info
->genlhdr
->cmd
) {
264 case NET_DM_CMD_START
:
265 return set_all_monitor_traces(TRACE_ON
);
267 case NET_DM_CMD_STOP
:
268 return set_all_monitor_traces(TRACE_OFF
);
275 static int dropmon_net_event(struct notifier_block
*ev_block
,
276 unsigned long event
, void *ptr
)
278 struct net_device
*dev
= ptr
;
279 struct dm_hw_stat_delta
*new_stat
= NULL
;
280 struct dm_hw_stat_delta
*tmp
;
283 case NETDEV_REGISTER
:
284 new_stat
= kzalloc(sizeof(struct dm_hw_stat_delta
), GFP_KERNEL
);
290 INIT_RCU_HEAD(&new_stat
->rcu
);
291 spin_lock(&trace_state_lock
);
292 list_add_rcu(&new_stat
->list
, &hw_stats_list
);
293 spin_unlock(&trace_state_lock
);
295 case NETDEV_UNREGISTER
:
296 spin_lock(&trace_state_lock
);
297 list_for_each_entry_safe(new_stat
, tmp
, &hw_stats_list
, list
) {
298 if (new_stat
->dev
== dev
) {
299 new_stat
->dev
= NULL
;
300 if (trace_state
== TRACE_OFF
) {
301 list_del_rcu(&new_stat
->list
);
302 call_rcu(&new_stat
->rcu
, free_dm_hw_stat
);
307 spin_unlock(&trace_state_lock
);
314 static struct genl_ops dropmon_ops
[] = {
316 .cmd
= NET_DM_CMD_CONFIG
,
317 .doit
= net_dm_cmd_config
,
320 .cmd
= NET_DM_CMD_START
,
321 .doit
= net_dm_cmd_trace
,
324 .cmd
= NET_DM_CMD_STOP
,
325 .doit
= net_dm_cmd_trace
,
329 static struct notifier_block dropmon_net_notifier
= {
330 .notifier_call
= dropmon_net_event
333 static int __init
init_net_drop_monitor(void)
337 struct per_cpu_dm_data
*data
;
338 printk(KERN_INFO
"Initalizing network drop monitor service\n");
340 if (sizeof(void *) > 8) {
341 printk(KERN_ERR
"Unable to store program counters on this arch, Drop monitor failed\n");
345 if (genl_register_family(&net_drop_monitor_family
) < 0) {
346 printk(KERN_ERR
"Could not create drop monitor netlink family\n");
352 for (i
= 0; i
< ARRAY_SIZE(dropmon_ops
); i
++) {
353 ret
= genl_register_ops(&net_drop_monitor_family
,
356 printk(KERN_CRIT
"Failed to register operation %d\n",
362 rc
= register_netdevice_notifier(&dropmon_net_notifier
);
364 printk(KERN_CRIT
"Failed to register netdevice notifier\n");
370 for_each_present_cpu(cpu
) {
371 data
= &per_cpu(dm_cpu_data
, cpu
);
372 reset_per_cpu_data(data
);
373 INIT_WORK(&data
->dm_alert_work
, send_dm_alert
);
374 init_timer(&data
->send_timer
);
375 data
->send_timer
.data
= cpu
;
376 data
->send_timer
.function
= sched_send_work
;
382 genl_unregister_family(&net_drop_monitor_family
);
387 late_initcall(init_net_drop_monitor
);