Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 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> |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 25 | #include <net/netevent.h> |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 26 | |
| 27 | #include <trace/skb.h> |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 28 | #include <trace/napi.h> |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 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 | */ |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 43 | static int trace_state = TRACE_OFF; |
| 44 | static spinlock_t trace_state_lock = SPIN_LOCK_UNLOCKED; |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 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 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 53 | struct dm_hw_stat_delta { |
| 54 | struct net_device *dev; |
| 55 | struct list_head list; |
| 56 | struct rcu_head rcu; |
| 57 | unsigned long last_drop_val; |
| 58 | }; |
| 59 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 60 | static struct genl_family net_drop_monitor_family = { |
| 61 | .id = GENL_ID_GENERATE, |
| 62 | .hdrsize = 0, |
| 63 | .name = "NET_DM", |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 64 | .version = 2, |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 65 | .maxattr = NET_DM_CMD_MAX, |
| 66 | }; |
| 67 | |
| 68 | static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); |
| 69 | |
| 70 | static int dm_hit_limit = 64; |
| 71 | static int dm_delay = 1; |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 72 | static unsigned long dm_hw_check_delta = 2*HZ; |
| 73 | static LIST_HEAD(hw_stats_list); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 74 | |
| 75 | static void reset_per_cpu_data(struct per_cpu_dm_data *data) |
| 76 | { |
| 77 | size_t al; |
| 78 | struct net_dm_alert_msg *msg; |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 79 | struct nlattr *nla; |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 80 | |
| 81 | al = sizeof(struct net_dm_alert_msg); |
| 82 | al += dm_hit_limit * sizeof(struct net_dm_drop_point); |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 83 | al += sizeof(struct nlattr); |
| 84 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 85 | data->skb = genlmsg_new(al, GFP_KERNEL); |
| 86 | genlmsg_put(data->skb, 0, 0, &net_drop_monitor_family, |
| 87 | 0, NET_DM_CMD_ALERT); |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 88 | nla = nla_reserve(data->skb, NLA_UNSPEC, sizeof(struct net_dm_alert_msg)); |
| 89 | msg = nla_data(nla); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 90 | memset(msg, 0, al); |
| 91 | atomic_set(&data->dm_hit_count, dm_hit_limit); |
| 92 | } |
| 93 | |
| 94 | static void send_dm_alert(struct work_struct *unused) |
| 95 | { |
| 96 | struct sk_buff *skb; |
| 97 | struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); |
| 98 | |
| 99 | /* |
| 100 | * Grab the skb we're about to send |
| 101 | */ |
| 102 | skb = data->skb; |
| 103 | |
| 104 | /* |
| 105 | * Replace it with a new one |
| 106 | */ |
| 107 | reset_per_cpu_data(data); |
| 108 | |
| 109 | /* |
| 110 | * Ship it! |
| 111 | */ |
| 112 | genlmsg_multicast(skb, 0, NET_DM_GRP_ALERT, GFP_KERNEL); |
| 113 | |
| 114 | } |
| 115 | |
| 116 | /* |
| 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 |
| 121 | */ |
| 122 | static void sched_send_work(unsigned long unused) |
| 123 | { |
| 124 | struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); |
| 125 | |
| 126 | schedule_work(&data->dm_alert_work); |
| 127 | } |
| 128 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 129 | static void trace_drop_common(struct sk_buff *skb, void *location) |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 130 | { |
| 131 | struct net_dm_alert_msg *msg; |
| 132 | struct nlmsghdr *nlh; |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 133 | struct nlattr *nla; |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 134 | int i; |
| 135 | struct per_cpu_dm_data *data = &__get_cpu_var(dm_cpu_data); |
| 136 | |
| 137 | |
| 138 | if (!atomic_add_unless(&data->dm_hit_count, -1, 0)) { |
| 139 | /* |
| 140 | * we're already at zero, discard this hit |
| 141 | */ |
| 142 | goto out; |
| 143 | } |
| 144 | |
| 145 | nlh = (struct nlmsghdr *)data->skb->data; |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 146 | nla = genlmsg_data(nlmsg_data(nlh)); |
| 147 | msg = nla_data(nla); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 148 | for (i = 0; i < msg->entries; i++) { |
| 149 | if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) { |
| 150 | msg->points[i].count++; |
| 151 | goto out; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /* |
| 156 | * We need to create a new entry |
| 157 | */ |
| 158 | __nla_reserve_nohdr(data->skb, sizeof(struct net_dm_drop_point)); |
Neil Horman | 683703a | 2009-04-27 03:17:31 -0700 | [diff] [blame] | 159 | nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 160 | memcpy(msg->points[msg->entries].pc, &location, sizeof(void *)); |
| 161 | msg->points[msg->entries].count = 1; |
| 162 | msg->entries++; |
| 163 | |
| 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()); |
| 167 | } |
| 168 | |
| 169 | out: |
| 170 | return; |
| 171 | } |
| 172 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 173 | static void trace_kfree_skb_hit(struct sk_buff *skb, void *location) |
| 174 | { |
| 175 | trace_drop_common(skb, location); |
| 176 | } |
| 177 | |
| 178 | static void trace_napi_poll_hit(struct napi_struct *napi) |
| 179 | { |
| 180 | struct dm_hw_stat_delta *new_stat; |
| 181 | |
| 182 | /* |
| 183 | * Ratelimit our check time to dm_hw_check_delta jiffies |
| 184 | */ |
| 185 | if (!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta)) |
| 186 | return; |
| 187 | |
| 188 | rcu_read_lock(); |
| 189 | list_for_each_entry_rcu(new_stat, &hw_stats_list, list) { |
| 190 | if ((new_stat->dev == napi->dev) && |
| 191 | (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) { |
| 192 | trace_drop_common(NULL, NULL); |
| 193 | new_stat->last_drop_val = napi->dev->stats.rx_dropped; |
| 194 | break; |
| 195 | } |
| 196 | } |
| 197 | rcu_read_unlock(); |
| 198 | } |
| 199 | |
| 200 | |
| 201 | static void free_dm_hw_stat(struct rcu_head *head) |
| 202 | { |
| 203 | struct dm_hw_stat_delta *n; |
| 204 | n = container_of(head, struct dm_hw_stat_delta, rcu); |
| 205 | kfree(n); |
| 206 | } |
| 207 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 208 | static int set_all_monitor_traces(int state) |
| 209 | { |
| 210 | int rc = 0; |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 211 | struct dm_hw_stat_delta *new_stat = NULL; |
| 212 | struct dm_hw_stat_delta *temp; |
| 213 | |
| 214 | spin_lock(&trace_state_lock); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 215 | |
| 216 | switch (state) { |
| 217 | case TRACE_ON: |
| 218 | rc |= register_trace_kfree_skb(trace_kfree_skb_hit); |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 219 | rc |= register_trace_napi_poll(trace_napi_poll_hit); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 220 | break; |
| 221 | case TRACE_OFF: |
| 222 | rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit); |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 223 | rc |= unregister_trace_napi_poll(trace_napi_poll_hit); |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 224 | |
| 225 | tracepoint_synchronize_unregister(); |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 226 | |
| 227 | /* |
| 228 | * Clean the device list |
| 229 | */ |
| 230 | list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { |
| 231 | if (new_stat->dev == NULL) { |
| 232 | list_del_rcu(&new_stat->list); |
| 233 | call_rcu(&new_stat->rcu, free_dm_hw_stat); |
| 234 | } |
| 235 | } |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 236 | break; |
| 237 | default: |
| 238 | rc = 1; |
| 239 | break; |
| 240 | } |
| 241 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 242 | if (!rc) |
| 243 | trace_state = state; |
| 244 | |
| 245 | spin_unlock(&trace_state_lock); |
| 246 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 247 | if (rc) |
| 248 | return -EINPROGRESS; |
| 249 | return rc; |
| 250 | } |
| 251 | |
| 252 | |
| 253 | static int net_dm_cmd_config(struct sk_buff *skb, |
| 254 | struct genl_info *info) |
| 255 | { |
| 256 | return -ENOTSUPP; |
| 257 | } |
| 258 | |
| 259 | static int net_dm_cmd_trace(struct sk_buff *skb, |
| 260 | struct genl_info *info) |
| 261 | { |
| 262 | switch (info->genlhdr->cmd) { |
| 263 | case NET_DM_CMD_START: |
| 264 | return set_all_monitor_traces(TRACE_ON); |
| 265 | break; |
| 266 | case NET_DM_CMD_STOP: |
| 267 | return set_all_monitor_traces(TRACE_OFF); |
| 268 | break; |
| 269 | } |
| 270 | |
| 271 | return -ENOTSUPP; |
| 272 | } |
| 273 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 274 | static int dropmon_net_event(struct notifier_block *ev_block, |
| 275 | unsigned long event, void *ptr) |
| 276 | { |
| 277 | struct net_device *dev = ptr; |
| 278 | struct dm_hw_stat_delta *new_stat = NULL; |
| 279 | struct dm_hw_stat_delta *tmp; |
| 280 | |
| 281 | switch (event) { |
| 282 | case NETDEV_REGISTER: |
| 283 | new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); |
| 284 | |
| 285 | if (!new_stat) |
| 286 | goto out; |
| 287 | |
| 288 | new_stat->dev = dev; |
| 289 | INIT_RCU_HEAD(&new_stat->rcu); |
| 290 | spin_lock(&trace_state_lock); |
| 291 | list_add_rcu(&new_stat->list, &hw_stats_list); |
| 292 | spin_unlock(&trace_state_lock); |
| 293 | break; |
| 294 | case NETDEV_UNREGISTER: |
| 295 | spin_lock(&trace_state_lock); |
| 296 | list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { |
| 297 | if (new_stat->dev == dev) { |
| 298 | new_stat->dev = NULL; |
| 299 | if (trace_state == TRACE_OFF) { |
| 300 | list_del_rcu(&new_stat->list); |
| 301 | call_rcu(&new_stat->rcu, free_dm_hw_stat); |
| 302 | break; |
| 303 | } |
| 304 | } |
| 305 | } |
| 306 | spin_unlock(&trace_state_lock); |
| 307 | break; |
| 308 | } |
| 309 | out: |
| 310 | return NOTIFY_DONE; |
| 311 | } |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 312 | |
| 313 | static struct genl_ops dropmon_ops[] = { |
| 314 | { |
| 315 | .cmd = NET_DM_CMD_CONFIG, |
| 316 | .doit = net_dm_cmd_config, |
| 317 | }, |
| 318 | { |
| 319 | .cmd = NET_DM_CMD_START, |
| 320 | .doit = net_dm_cmd_trace, |
| 321 | }, |
| 322 | { |
| 323 | .cmd = NET_DM_CMD_STOP, |
| 324 | .doit = net_dm_cmd_trace, |
| 325 | }, |
| 326 | }; |
| 327 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 328 | static struct notifier_block dropmon_net_notifier = { |
| 329 | .notifier_call = dropmon_net_event |
| 330 | }; |
| 331 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 332 | static int __init init_net_drop_monitor(void) |
| 333 | { |
| 334 | int cpu; |
| 335 | int rc, i, ret; |
| 336 | struct per_cpu_dm_data *data; |
| 337 | printk(KERN_INFO "Initalizing network drop monitor service\n"); |
| 338 | |
| 339 | if (sizeof(void *) > 8) { |
| 340 | printk(KERN_ERR "Unable to store program counters on this arch, Drop monitor failed\n"); |
| 341 | return -ENOSPC; |
| 342 | } |
| 343 | |
| 344 | if (genl_register_family(&net_drop_monitor_family) < 0) { |
| 345 | printk(KERN_ERR "Could not create drop monitor netlink family\n"); |
| 346 | return -EFAULT; |
| 347 | } |
| 348 | |
| 349 | rc = -EFAULT; |
| 350 | |
| 351 | for (i = 0; i < ARRAY_SIZE(dropmon_ops); i++) { |
| 352 | ret = genl_register_ops(&net_drop_monitor_family, |
| 353 | &dropmon_ops[i]); |
| 354 | if (ret) { |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 355 | printk(KERN_CRIT "Failed to register operation %d\n", |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 356 | dropmon_ops[i].cmd); |
| 357 | goto out_unreg; |
| 358 | } |
| 359 | } |
| 360 | |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 361 | rc = register_netdevice_notifier(&dropmon_net_notifier); |
| 362 | if (rc < 0) { |
| 363 | printk(KERN_CRIT "Failed to register netdevice notifier\n"); |
| 364 | goto out_unreg; |
| 365 | } |
| 366 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 367 | rc = 0; |
| 368 | |
| 369 | for_each_present_cpu(cpu) { |
| 370 | data = &per_cpu(dm_cpu_data, cpu); |
| 371 | reset_per_cpu_data(data); |
| 372 | INIT_WORK(&data->dm_alert_work, send_dm_alert); |
| 373 | init_timer(&data->send_timer); |
| 374 | data->send_timer.data = cpu; |
| 375 | data->send_timer.function = sched_send_work; |
| 376 | } |
Neil Horman | 4ea7e38 | 2009-05-21 07:36:08 +0000 | [diff] [blame] | 377 | |
Neil Horman | 9a8afc8 | 2009-03-11 09:51:26 +0000 | [diff] [blame] | 378 | goto out; |
| 379 | |
| 380 | out_unreg: |
| 381 | genl_unregister_family(&net_drop_monitor_family); |
| 382 | out: |
| 383 | return rc; |
| 384 | } |
| 385 | |
| 386 | late_initcall(init_net_drop_monitor); |