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Commit | Line | Data |
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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> | |
5a0e3ad6 | 24 | #include <linux/slab.h> |
9a8afc8d | 25 | #include <net/genetlink.h> |
4ea7e386 | 26 | #include <net/netevent.h> |
9a8afc8d | 27 | |
ad8d75ff | 28 | #include <trace/events/skb.h> |
9cbc1cb8 | 29 | #include <trace/events/napi.h> |
9a8afc8d NH |
30 | |
31 | #include <asm/unaligned.h> | |
32 | ||
33 | #define TRACE_ON 1 | |
34 | #define TRACE_OFF 0 | |
35 | ||
36 | static 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 | */ | |
4ea7e386 | 44 | static int trace_state = TRACE_OFF; |
d3bcfefa | 45 | static DEFINE_SPINLOCK(trace_state_lock); |
9a8afc8d NH |
46 | |
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; | |
52 | }; | |
53 | ||
4ea7e386 NH |
54 | struct dm_hw_stat_delta { |
55 | struct net_device *dev; | |
5848cc09 | 56 | unsigned long last_rx; |
4ea7e386 NH |
57 | struct list_head list; |
58 | struct rcu_head rcu; | |
59 | unsigned long last_drop_val; | |
60 | }; | |
61 | ||
9a8afc8d NH |
62 | static struct genl_family net_drop_monitor_family = { |
63 | .id = GENL_ID_GENERATE, | |
64 | .hdrsize = 0, | |
65 | .name = "NET_DM", | |
683703a2 | 66 | .version = 2, |
9a8afc8d NH |
67 | .maxattr = NET_DM_CMD_MAX, |
68 | }; | |
69 | ||
70 | static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); | |
71 | ||
72 | static int dm_hit_limit = 64; | |
73 | static int dm_delay = 1; | |
4ea7e386 NH |
74 | static unsigned long dm_hw_check_delta = 2*HZ; |
75 | static LIST_HEAD(hw_stats_list); | |
9a8afc8d NH |
76 | |
77 | static void reset_per_cpu_data(struct per_cpu_dm_data *data) | |
78 | { | |
79 | size_t al; | |
80 | struct net_dm_alert_msg *msg; | |
683703a2 | 81 | struct nlattr *nla; |
9a8afc8d NH |
82 | |
83 | al = sizeof(struct net_dm_alert_msg); | |
84 | al += dm_hit_limit * sizeof(struct net_dm_drop_point); | |
683703a2 NH |
85 | al += sizeof(struct nlattr); |
86 | ||
9a8afc8d NH |
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); | |
683703a2 NH |
90 | nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); |
91 | msg = nla_data(nla); | |
9a8afc8d NH |
92 | memset(msg, 0, al); |
93 | atomic_set(&data->dm_hit_count, dm_hit_limit); | |
94 | } | |
95 | ||
96 | static 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 | */ | |
124 | static 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 | ||
4ea7e386 | 131 | static void trace_drop_common(struct sk_buff *skb, void *location) |
9a8afc8d NH |
132 | { |
133 | struct net_dm_alert_msg *msg; | |
134 | struct nlmsghdr *nlh; | |
683703a2 | 135 | struct nlattr *nla; |
9a8afc8d NH |
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; | |
683703a2 NH |
148 | nla = genlmsg_data(nlmsg_data(nlh)); |
149 | msg = nla_data(nla); | |
9a8afc8d NH |
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)); | |
683703a2 | 161 | nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); |
9a8afc8d NH |
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 | ||
171 | out: | |
172 | return; | |
173 | } | |
174 | ||
38516ab5 | 175 | static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location) |
4ea7e386 NH |
176 | { |
177 | trace_drop_common(skb, location); | |
178 | } | |
179 | ||
38516ab5 | 180 | static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi) |
4ea7e386 NH |
181 | { |
182 | struct dm_hw_stat_delta *new_stat; | |
183 | ||
184 | /* | |
5848cc09 | 185 | * Don't check napi structures with no associated device |
4ea7e386 | 186 | */ |
5848cc09 | 187 | if (!napi->dev) |
4ea7e386 NH |
188 | return; |
189 | ||
190 | rcu_read_lock(); | |
191 | list_for_each_entry_rcu(new_stat, &hw_stats_list, list) { | |
5848cc09 NH |
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 | */ | |
4ea7e386 | 198 | if ((new_stat->dev == napi->dev) && |
5848cc09 | 199 | (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) && |
4ea7e386 NH |
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; | |
5848cc09 | 203 | new_stat->last_rx = jiffies; |
4ea7e386 NH |
204 | break; |
205 | } | |
206 | } | |
207 | rcu_read_unlock(); | |
208 | } | |
209 | ||
210 | ||
211 | static void free_dm_hw_stat(struct rcu_head *head) | |
212 | { | |
213 | struct dm_hw_stat_delta *n; | |
214 | n = container_of(head, struct dm_hw_stat_delta, rcu); | |
215 | kfree(n); | |
216 | } | |
217 | ||
9a8afc8d NH |
218 | static int set_all_monitor_traces(int state) |
219 | { | |
220 | int rc = 0; | |
4ea7e386 NH |
221 | struct dm_hw_stat_delta *new_stat = NULL; |
222 | struct dm_hw_stat_delta *temp; | |
223 | ||
224 | spin_lock(&trace_state_lock); | |
9a8afc8d | 225 | |
4b706372 NH |
226 | if (state == trace_state) { |
227 | rc = -EAGAIN; | |
228 | goto out_unlock; | |
229 | } | |
230 | ||
9a8afc8d NH |
231 | switch (state) { |
232 | case TRACE_ON: | |
38516ab5 SR |
233 | rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL); |
234 | rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL); | |
9a8afc8d NH |
235 | break; |
236 | case TRACE_OFF: | |
38516ab5 SR |
237 | rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL); |
238 | rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL); | |
9a8afc8d NH |
239 | |
240 | tracepoint_synchronize_unregister(); | |
4ea7e386 NH |
241 | |
242 | /* | |
243 | * Clean the device list | |
244 | */ | |
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); | |
249 | } | |
250 | } | |
9a8afc8d NH |
251 | break; |
252 | default: | |
253 | rc = 1; | |
254 | break; | |
255 | } | |
256 | ||
4ea7e386 NH |
257 | if (!rc) |
258 | trace_state = state; | |
4b706372 NH |
259 | else |
260 | rc = -EINPROGRESS; | |
4ea7e386 | 261 | |
4b706372 | 262 | out_unlock: |
4ea7e386 NH |
263 | spin_unlock(&trace_state_lock); |
264 | ||
9a8afc8d NH |
265 | return rc; |
266 | } | |
267 | ||
268 | ||
269 | static int net_dm_cmd_config(struct sk_buff *skb, | |
270 | struct genl_info *info) | |
271 | { | |
272 | return -ENOTSUPP; | |
273 | } | |
274 | ||
275 | static int net_dm_cmd_trace(struct sk_buff *skb, | |
276 | struct genl_info *info) | |
277 | { | |
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; | |
285 | } | |
286 | ||
287 | return -ENOTSUPP; | |
288 | } | |
289 | ||
4ea7e386 NH |
290 | static int dropmon_net_event(struct notifier_block *ev_block, |
291 | unsigned long event, void *ptr) | |
292 | { | |
293 | struct net_device *dev = ptr; | |
294 | struct dm_hw_stat_delta *new_stat = NULL; | |
295 | struct dm_hw_stat_delta *tmp; | |
296 | ||
297 | switch (event) { | |
298 | case NETDEV_REGISTER: | |
299 | new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); | |
300 | ||
301 | if (!new_stat) | |
302 | goto out; | |
303 | ||
304 | new_stat->dev = dev; | |
5848cc09 | 305 | new_stat->last_rx = jiffies; |
4ea7e386 NH |
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; | |
319 | } | |
320 | } | |
321 | } | |
322 | spin_unlock(&trace_state_lock); | |
323 | break; | |
324 | } | |
325 | out: | |
326 | return NOTIFY_DONE; | |
327 | } | |
9a8afc8d NH |
328 | |
329 | static struct genl_ops dropmon_ops[] = { | |
330 | { | |
331 | .cmd = NET_DM_CMD_CONFIG, | |
332 | .doit = net_dm_cmd_config, | |
333 | }, | |
334 | { | |
335 | .cmd = NET_DM_CMD_START, | |
336 | .doit = net_dm_cmd_trace, | |
337 | }, | |
338 | { | |
339 | .cmd = NET_DM_CMD_STOP, | |
340 | .doit = net_dm_cmd_trace, | |
341 | }, | |
342 | }; | |
343 | ||
4ea7e386 NH |
344 | static struct notifier_block dropmon_net_notifier = { |
345 | .notifier_call = dropmon_net_event | |
346 | }; | |
347 | ||
9a8afc8d NH |
348 | static int __init init_net_drop_monitor(void) |
349 | { | |
9a8afc8d | 350 | struct per_cpu_dm_data *data; |
a256be70 CG |
351 | int cpu, rc; |
352 | ||
ac0a121d | 353 | printk(KERN_INFO "Initializing network drop monitor service\n"); |
9a8afc8d NH |
354 | |
355 | if (sizeof(void *) > 8) { | |
356 | printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n"); | |
357 | return -ENOSPC; | |
358 | } | |
359 | ||
a256be70 CG |
360 | rc = genl_register_family_with_ops(&net_drop_monitor_family, |
361 | dropmon_ops, | |
362 | ARRAY_SIZE(dropmon_ops)); | |
363 | if (rc) { | |
9a8afc8d | 364 | printk(KERN_ERR "Could not create drop monitor netlink family\n"); |
a256be70 | 365 | return rc; |
9a8afc8d NH |
366 | } |
367 | ||
4ea7e386 NH |
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; | |
372 | } | |
373 | ||
9a8afc8d NH |
374 | rc = 0; |
375 | ||
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; | |
383 | } | |
4ea7e386 | 384 | |
9a8afc8d NH |
385 | goto out; |
386 | ||
387 | out_unreg: | |
388 | genl_unregister_family(&net_drop_monitor_family); | |
389 | out: | |
390 | return rc; | |
391 | } | |
392 | ||
393 | late_initcall(init_net_drop_monitor); |