Commit | Line | Data |
---|---|---|
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 | ||
35 | static 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 | 43 | static int trace_state = TRACE_OFF; |
d3bcfefa | 44 | static DEFINE_SPINLOCK(trace_state_lock); |
9a8afc8d NH |
45 | |
46 | struct 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 |
53 | struct 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 |
61 | static 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 | ||
69 | static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); | |
70 | ||
71 | static int dm_hit_limit = 64; | |
72 | static int dm_delay = 1; | |
4ea7e386 NH |
73 | static unsigned long dm_hw_check_delta = 2*HZ; |
74 | static LIST_HEAD(hw_stats_list); | |
9a8afc8d NH |
75 | |
76 | static 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 | ||
95 | static 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 | */ | |
123 | static 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 | 130 | static 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 | ||
170 | out: | |
171 | return; | |
172 | } | |
173 | ||
4ea7e386 NH |
174 | static void trace_kfree_skb_hit(struct sk_buff *skb, void *location) |
175 | { | |
176 | trace_drop_common(skb, location); | |
177 | } | |
178 | ||
179 | static 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 | ||
210 | static 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 |
217 | static 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 | ||
262 | static int net_dm_cmd_config(struct sk_buff *skb, | |
263 | struct genl_info *info) | |
264 | { | |
265 | return -ENOTSUPP; | |
266 | } | |
267 | ||
268 | static 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 |
283 | static 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 | } | |
319 | out: | |
320 | return NOTIFY_DONE; | |
321 | } | |
9a8afc8d NH |
322 | |
323 | static 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 |
338 | static struct notifier_block dropmon_net_notifier = { |
339 | .notifier_call = dropmon_net_event | |
340 | }; | |
341 | ||
9a8afc8d NH |
342 | static 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 | ||
390 | out_unreg: | |
391 | genl_unregister_family(&net_drop_monitor_family); | |
392 | out: | |
393 | return rc; | |
394 | } | |
395 | ||
396 | late_initcall(init_net_drop_monitor); |