net/core/drop_monitor.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Monitoring code for network dropped packet alerts
   4  *
   5  * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/netdevice.h>
  11 #include <linux/etherdevice.h>
  12 #include <linux/string.h>
  13 #include <linux/if_arp.h>
  14 #include <linux/inetdevice.h>
  15 #include <linux/inet.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/netpoll.h>
  18 #include <linux/sched.h>
  19 #include <linux/delay.h>
  20 #include <linux/types.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/netlink.h>
  23 #include <linux/net_dropmon.h>
  24 #include <linux/percpu.h>
  25 #include <linux/timer.h>
  26 #include <linux/bitops.h>
  27 #include <linux/slab.h>
  28 #include <linux/module.h>
  29 #include <net/drop_monitor.h>
  30 #include <net/genetlink.h>
  31 #include <net/netevent.h>
  32
  33 #include <trace/events/skb.h>
  34 #include <trace/events/napi.h>
  35
  36 #include <asm/unaligned.h>
  37
  38 #define TRACE_ON 1
  39 #define TRACE_OFF 0
  40
  41 /*
  42  * Globals, our netlink socket pointer
  43  * and the work handle that will send up
  44  * netlink alerts
  45  */
  46 static int trace_state = TRACE_OFF;
  47 static bool monitor_hw;
  48
  49 /* net_dm_mutex
  50  *
  51  * An overall lock guarding every operation coming from userspace.
  52  * It also guards the global 'hw_stats_list' list.
  53  */
  54 static DEFINE_MUTEX(net_dm_mutex);
  55
  56 struct net_dm_stats {
  57         u64 dropped;
  58         struct u64_stats_sync syncp;
  59 };
  60
  61 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
  62
  63 struct net_dm_hw_entry {
  64         char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  65         u32 count;
  66 };
  67
  68 struct net_dm_hw_entries {
  69         u32 num_entries;
  70         struct net_dm_hw_entry entries[0];
  71 };
  72
  73 struct per_cpu_dm_data {
  74         spinlock_t              lock;   /* Protects 'skb', 'hw_entries' and
  75                                          * 'send_timer'
  76                                          */
  77         union {
  78                 struct sk_buff                  *skb;
  79                 struct net_dm_hw_entries        *hw_entries;
  80         };
  81         struct sk_buff_head     drop_queue;
  82         struct work_struct      dm_alert_work;
  83         struct timer_list       send_timer;
  84         struct net_dm_stats     stats;
  85 };
  86
  87 struct dm_hw_stat_delta {
  88         struct net_device *dev;
  89         unsigned long last_rx;
  90         struct list_head list;
  91         struct rcu_head rcu;
  92         unsigned long last_drop_val;
  93 };
  94
  95 static struct genl_family net_drop_monitor_family;
  96
  97 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
  98 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
  99
 100 static int dm_hit_limit = 64;
 101 static int dm_delay = 1;
 102 static unsigned long dm_hw_check_delta = 2*HZ;
 103 static LIST_HEAD(hw_stats_list);
 104
 105 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 106 static u32 net_dm_trunc_len;
 107 static u32 net_dm_queue_len = 1000;
 108
 109 struct net_dm_alert_ops {
 110         void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
 111                                 void *location);
 112         void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 113                                 int work, int budget);
 114         void (*work_item_func)(struct work_struct *work);
 115         void (*hw_work_item_func)(struct work_struct *work);
 116         void (*hw_probe)(struct sk_buff *skb,
 117                          const struct net_dm_hw_metadata *hw_metadata);
 118 };
 119
 120 struct net_dm_skb_cb {
 121         union {
 122                 struct net_dm_hw_metadata *hw_metadata;
 123                 void *pc;
 124         };
 125 };
 126
 127 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
 128
 129 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 130 {
 131         size_t al;
 132         struct net_dm_alert_msg *msg;
 133         struct nlattr *nla;
 134         struct sk_buff *skb;
 135         unsigned long flags;
 136         void *msg_header;
 137
 138         al = sizeof(struct net_dm_alert_msg);
 139         al += dm_hit_limit * sizeof(struct net_dm_drop_point);
 140         al += sizeof(struct nlattr);
 141
 142         skb = genlmsg_new(al, GFP_KERNEL);
 143
 144         if (!skb)
 145                 goto err;
 146
 147         msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
 148                                  0, NET_DM_CMD_ALERT);
 149         if (!msg_header) {
 150                 nlmsg_free(skb);
 151                 skb = NULL;
 152                 goto err;
 153         }
 154         nla = nla_reserve(skb, NLA_UNSPEC,
 155                           sizeof(struct net_dm_alert_msg));
 156         if (!nla) {
 157                 nlmsg_free(skb);
 158                 skb = NULL;
 159                 goto err;
 160         }
 161         msg = nla_data(nla);
 162         memset(msg, 0, al);
 163         goto out;
 164
 165 err:
 166         mod_timer(&data->send_timer, jiffies + HZ / 10);
 167 out:
 168         spin_lock_irqsave(&data->lock, flags);
 169         swap(data->skb, skb);
 170         spin_unlock_irqrestore(&data->lock, flags);
 171
 172         if (skb) {
 173                 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
 174                 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
 175
 176                 genlmsg_end(skb, genlmsg_data(gnlh));
 177         }
 178
 179         return skb;
 180 }
 181
 182 static const struct genl_multicast_group dropmon_mcgrps[] = {
 183         { .name = "events", },
 184 };
 185
 186 static void send_dm_alert(struct work_struct *work)
 187 {
 188         struct sk_buff *skb;
 189         struct per_cpu_dm_data *data;
 190
 191         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 192
 193         skb = reset_per_cpu_data(data);
 194
 195         if (skb)
 196                 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
 197                                   0, GFP_KERNEL);
 198 }
 199
 200 /*
 201  * This is the timer function to delay the sending of an alert
 202  * in the event that more drops will arrive during the
 203  * hysteresis period.
 204  */
 205 static void sched_send_work(struct timer_list *t)
 206 {
 207         struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
 208
 209         schedule_work(&data->dm_alert_work);
 210 }
 211
 212 static void trace_drop_common(struct sk_buff *skb, void *location)
 213 {
 214         struct net_dm_alert_msg *msg;
 215         struct net_dm_drop_point *point;
 216         struct nlmsghdr *nlh;
 217         struct nlattr *nla;
 218         int i;
 219         struct sk_buff *dskb;
 220         struct per_cpu_dm_data *data;
 221         unsigned long flags;
 222
 223         local_irq_save(flags);
 224         data = this_cpu_ptr(&dm_cpu_data);
 225         spin_lock(&data->lock);
 226         dskb = data->skb;
 227
 228         if (!dskb)
 229                 goto out;
 230
 231         nlh = (struct nlmsghdr *)dskb->data;
 232         nla = genlmsg_data(nlmsg_data(nlh));
 233         msg = nla_data(nla);
 234         point = msg->points;
 235         for (i = 0; i < msg->entries; i++) {
 236                 if (!memcmp(&location, &point->pc, sizeof(void *))) {
 237                         point->count++;
 238                         goto out;
 239                 }
 240                 point++;
 241         }
 242         if (msg->entries == dm_hit_limit)
 243                 goto out;
 244         /*
 245          * We need to create a new entry
 246          */
 247         __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
 248         nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
 249         memcpy(point->pc, &location, sizeof(void *));
 250         point->count = 1;
 251         msg->entries++;
 252
 253         if (!timer_pending(&data->send_timer)) {
 254                 data->send_timer.expires = jiffies + dm_delay * HZ;
 255                 add_timer(&data->send_timer);
 256         }
 257
 258 out:
 259         spin_unlock_irqrestore(&data->lock, flags);
 260 }
 261
 262 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
 263 {
 264         trace_drop_common(skb, location);
 265 }
 266
 267 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 268                                 int work, int budget)
 269 {
 270         struct dm_hw_stat_delta *new_stat;
 271
 272         /*
 273          * Don't check napi structures with no associated device
 274          */
 275         if (!napi->dev)
 276                 return;
 277
 278         rcu_read_lock();
 279         list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
 280                 struct net_device *dev;
 281
 282                 /*
 283                  * only add a note to our monitor buffer if:
 284                  * 1) this is the dev we received on
 285                  * 2) its after the last_rx delta
 286                  * 3) our rx_dropped count has gone up
 287                  */
 288                 /* Paired with WRITE_ONCE() in dropmon_net_event() */
 289                 dev = READ_ONCE(new_stat->dev);
 290                 if ((dev == napi->dev)  &&
 291                     (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
 292                     (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
 293                         trace_drop_common(NULL, NULL);
 294                         new_stat->last_drop_val = napi->dev->stats.rx_dropped;
 295                         new_stat->last_rx = jiffies;
 296                         break;
 297                 }
 298         }
 299         rcu_read_unlock();
 300 }
 301
 302 static struct net_dm_hw_entries *
 303 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 304 {
 305         struct net_dm_hw_entries *hw_entries;
 306         unsigned long flags;
 307
 308         hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
 309                              GFP_KERNEL);
 310         if (!hw_entries) {
 311                 /* If the memory allocation failed, we try to perform another
 312                  * allocation in 1/10 second. Otherwise, the probe function
 313                  * will constantly bail out.
 314                  */
 315                 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 316         }
 317
 318         spin_lock_irqsave(&hw_data->lock, flags);
 319         swap(hw_data->hw_entries, hw_entries);
 320         spin_unlock_irqrestore(&hw_data->lock, flags);
 321
 322         return hw_entries;
 323 }
 324
 325 static int net_dm_hw_entry_put(struct sk_buff *msg,
 326                                const struct net_dm_hw_entry *hw_entry)
 327 {
 328         struct nlattr *attr;
 329
 330         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
 331         if (!attr)
 332                 return -EMSGSIZE;
 333
 334         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
 335                 goto nla_put_failure;
 336
 337         if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
 338                 goto nla_put_failure;
 339
 340         nla_nest_end(msg, attr);
 341
 342         return 0;
 343
 344 nla_put_failure:
 345         nla_nest_cancel(msg, attr);
 346         return -EMSGSIZE;
 347 }
 348
 349 static int net_dm_hw_entries_put(struct sk_buff *msg,
 350                                  const struct net_dm_hw_entries *hw_entries)
 351 {
 352         struct nlattr *attr;
 353         int i;
 354
 355         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
 356         if (!attr)
 357                 return -EMSGSIZE;
 358
 359         for (i = 0; i < hw_entries->num_entries; i++) {
 360                 int rc;
 361
 362                 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
 363                 if (rc)
 364                         goto nla_put_failure;
 365         }
 366
 367         nla_nest_end(msg, attr);
 368
 369         return 0;
 370
 371 nla_put_failure:
 372         nla_nest_cancel(msg, attr);
 373         return -EMSGSIZE;
 374 }
 375
 376 static int
 377 net_dm_hw_summary_report_fill(struct sk_buff *msg,
 378                               const struct net_dm_hw_entries *hw_entries)
 379 {
 380         struct net_dm_alert_msg anc_hdr = { 0 };
 381         void *hdr;
 382         int rc;
 383
 384         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 385                           NET_DM_CMD_ALERT);
 386         if (!hdr)
 387                 return -EMSGSIZE;
 388
 389         /* We need to put the ancillary header in order not to break user
 390          * space.
 391          */
 392         if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
 393                 goto nla_put_failure;
 394
 395         rc = net_dm_hw_entries_put(msg, hw_entries);
 396         if (rc)
 397                 goto nla_put_failure;
 398
 399         genlmsg_end(msg, hdr);
 400
 401         return 0;
 402
 403 nla_put_failure:
 404         genlmsg_cancel(msg, hdr);
 405         return -EMSGSIZE;
 406 }
 407
 408 static void net_dm_hw_summary_work(struct work_struct *work)
 409 {
 410         struct net_dm_hw_entries *hw_entries;
 411         struct per_cpu_dm_data *hw_data;
 412         struct sk_buff *msg;
 413         int rc;
 414
 415         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 416
 417         hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
 418         if (!hw_entries)
 419                 return;
 420
 421         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 422         if (!msg)
 423                 goto out;
 424
 425         rc = net_dm_hw_summary_report_fill(msg, hw_entries);
 426         if (rc) {
 427                 nlmsg_free(msg);
 428                 goto out;
 429         }
 430
 431         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 432
 433 out:
 434         kfree(hw_entries);
 435 }
 436
 437 static void
 438 net_dm_hw_summary_probe(struct sk_buff *skb,
 439                         const struct net_dm_hw_metadata *hw_metadata)
 440 {
 441         struct net_dm_hw_entries *hw_entries;
 442         struct net_dm_hw_entry *hw_entry;
 443         struct per_cpu_dm_data *hw_data;
 444         unsigned long flags;
 445         int i;
 446
 447         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 448         spin_lock_irqsave(&hw_data->lock, flags);
 449         hw_entries = hw_data->hw_entries;
 450
 451         if (!hw_entries)
 452                 goto out;
 453
 454         for (i = 0; i < hw_entries->num_entries; i++) {
 455                 hw_entry = &hw_entries->entries[i];
 456                 if (!strncmp(hw_entry->trap_name, hw_metadata->trap_name,
 457                              NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
 458                         hw_entry->count++;
 459                         goto out;
 460                 }
 461         }
 462         if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
 463                 goto out;
 464
 465         hw_entry = &hw_entries->entries[hw_entries->num_entries];
 466         strlcpy(hw_entry->trap_name, hw_metadata->trap_name,
 467                 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
 468         hw_entry->count = 1;
 469         hw_entries->num_entries++;
 470
 471         if (!timer_pending(&hw_data->send_timer)) {
 472                 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
 473                 add_timer(&hw_data->send_timer);
 474         }
 475
 476 out:
 477         spin_unlock_irqrestore(&hw_data->lock, flags);
 478 }
 479
 480 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 481         .kfree_skb_probe        = trace_kfree_skb_hit,
 482         .napi_poll_probe        = trace_napi_poll_hit,
 483         .work_item_func         = send_dm_alert,
 484         .hw_work_item_func      = net_dm_hw_summary_work,
 485         .hw_probe               = net_dm_hw_summary_probe,
 486 };
 487
 488 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 489                                               struct sk_buff *skb,
 490                                               void *location)
 491 {
 492         ktime_t tstamp = ktime_get_real();
 493         struct per_cpu_dm_data *data;
 494         struct sk_buff *nskb;
 495         unsigned long flags;
 496
 497         if (!skb_mac_header_was_set(skb))
 498                 return;
 499
 500         nskb = skb_clone(skb, GFP_ATOMIC);
 501         if (!nskb)
 502                 return;
 503
 504         NET_DM_SKB_CB(nskb)->pc = location;
 505         /* Override the timestamp because we care about the time when the
 506          * packet was dropped.
 507          */
 508         nskb->tstamp = tstamp;
 509
 510         data = this_cpu_ptr(&dm_cpu_data);
 511
 512         spin_lock_irqsave(&data->drop_queue.lock, flags);
 513         if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
 514                 __skb_queue_tail(&data->drop_queue, nskb);
 515         else
 516                 goto unlock_free;
 517         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 518
 519         schedule_work(&data->dm_alert_work);
 520
 521         return;
 522
 523 unlock_free:
 524         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 525         u64_stats_update_begin(&data->stats.syncp);
 526         data->stats.dropped++;
 527         u64_stats_update_end(&data->stats.syncp);
 528         consume_skb(nskb);
 529 }
 530
 531 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
 532                                               struct napi_struct *napi,
 533                                               int work, int budget)
 534 {
 535 }
 536
 537 static size_t net_dm_in_port_size(void)
 538 {
 539                /* NET_DM_ATTR_IN_PORT nest */
 540         return nla_total_size(0) +
 541                /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
 542                nla_total_size(sizeof(u32)) +
 543                /* NET_DM_ATTR_PORT_NETDEV_NAME */
 544                nla_total_size(IFNAMSIZ + 1);
 545 }
 546
 547 #define NET_DM_MAX_SYMBOL_LEN 40
 548
 549 static size_t net_dm_packet_report_size(size_t payload_len)
 550 {
 551         size_t size;
 552
 553         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 554
 555         return NLMSG_ALIGN(size) +
 556                /* NET_DM_ATTR_ORIGIN */
 557                nla_total_size(sizeof(u16)) +
 558                /* NET_DM_ATTR_PC */
 559                nla_total_size(sizeof(u64)) +
 560                /* NET_DM_ATTR_SYMBOL */
 561                nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
 562                /* NET_DM_ATTR_IN_PORT */
 563                net_dm_in_port_size() +
 564                /* NET_DM_ATTR_TIMESTAMP */
 565                nla_total_size(sizeof(u64)) +
 566                /* NET_DM_ATTR_ORIG_LEN */
 567                nla_total_size(sizeof(u32)) +
 568                /* NET_DM_ATTR_PROTO */
 569                nla_total_size(sizeof(u16)) +
 570                /* NET_DM_ATTR_PAYLOAD */
 571                nla_total_size(payload_len);
 572 }
 573
 574 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
 575                                             const char *name)
 576 {
 577         struct nlattr *attr;
 578
 579         attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
 580         if (!attr)
 581                 return -EMSGSIZE;
 582
 583         if (ifindex &&
 584             nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
 585                 goto nla_put_failure;
 586
 587         if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
 588                 goto nla_put_failure;
 589
 590         nla_nest_end(msg, attr);
 591
 592         return 0;
 593
 594 nla_put_failure:
 595         nla_nest_cancel(msg, attr);
 596         return -EMSGSIZE;
 597 }
 598
 599 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
 600                                      size_t payload_len)
 601 {
 602         u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
 603         char buf[NET_DM_MAX_SYMBOL_LEN];
 604         struct nlattr *attr;
 605         void *hdr;
 606         int rc;
 607
 608         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 609                           NET_DM_CMD_PACKET_ALERT);
 610         if (!hdr)
 611                 return -EMSGSIZE;
 612
 613         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
 614                 goto nla_put_failure;
 615
 616         if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
 617                 goto nla_put_failure;
 618
 619         snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
 620         if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
 621                 goto nla_put_failure;
 622
 623         rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
 624         if (rc)
 625                 goto nla_put_failure;
 626
 627         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 628                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 629                 goto nla_put_failure;
 630
 631         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 632                 goto nla_put_failure;
 633
 634         if (!payload_len)
 635                 goto out;
 636
 637         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 638                 goto nla_put_failure;
 639
 640         attr = skb_put(msg, nla_total_size(payload_len));
 641         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 642         attr->nla_len = nla_attr_size(payload_len);
 643         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 644                 goto nla_put_failure;
 645
 646 out:
 647         genlmsg_end(msg, hdr);
 648
 649         return 0;
 650
 651 nla_put_failure:
 652         genlmsg_cancel(msg, hdr);
 653         return -EMSGSIZE;
 654 }
 655
 656 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
 657
 658 static void net_dm_packet_report(struct sk_buff *skb)
 659 {
 660         struct sk_buff *msg;
 661         size_t payload_len;
 662         int rc;
 663
 664         /* Make sure we start copying the packet from the MAC header */
 665         if (skb->data > skb_mac_header(skb))
 666                 skb_push(skb, skb->data - skb_mac_header(skb));
 667         else
 668                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 669
 670         /* Ensure packet fits inside a single netlink attribute */
 671         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 672         if (net_dm_trunc_len)
 673                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 674
 675         msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
 676         if (!msg)
 677                 goto out;
 678
 679         rc = net_dm_packet_report_fill(msg, skb, payload_len);
 680         if (rc) {
 681                 nlmsg_free(msg);
 682                 goto out;
 683         }
 684
 685         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 686
 687 out:
 688         consume_skb(skb);
 689 }
 690
 691 static void net_dm_packet_work(struct work_struct *work)
 692 {
 693         struct per_cpu_dm_data *data;
 694         struct sk_buff_head list;
 695         struct sk_buff *skb;
 696         unsigned long flags;
 697
 698         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 699
 700         __skb_queue_head_init(&list);
 701
 702         spin_lock_irqsave(&data->drop_queue.lock, flags);
 703         skb_queue_splice_tail_init(&data->drop_queue, &list);
 704         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 705
 706         while ((skb = __skb_dequeue(&list)))
 707                 net_dm_packet_report(skb);
 708 }
 709
 710 static size_t
 711 net_dm_hw_packet_report_size(size_t payload_len,
 712                              const struct net_dm_hw_metadata *hw_metadata)
 713 {
 714         size_t size;
 715
 716         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 717
 718         return NLMSG_ALIGN(size) +
 719                /* NET_DM_ATTR_ORIGIN */
 720                nla_total_size(sizeof(u16)) +
 721                /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
 722                nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
 723                /* NET_DM_ATTR_HW_TRAP_NAME */
 724                nla_total_size(strlen(hw_metadata->trap_name) + 1) +
 725                /* NET_DM_ATTR_IN_PORT */
 726                net_dm_in_port_size() +
 727                /* NET_DM_ATTR_TIMESTAMP */
 728                nla_total_size(sizeof(u64)) +
 729                /* NET_DM_ATTR_ORIG_LEN */
 730                nla_total_size(sizeof(u32)) +
 731                /* NET_DM_ATTR_PROTO */
 732                nla_total_size(sizeof(u16)) +
 733                /* NET_DM_ATTR_PAYLOAD */
 734                nla_total_size(payload_len);
 735 }
 736
 737 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 738                                         struct sk_buff *skb, size_t payload_len)
 739 {
 740         struct net_dm_hw_metadata *hw_metadata;
 741         struct nlattr *attr;
 742         void *hdr;
 743
 744         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 745
 746         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 747                           NET_DM_CMD_PACKET_ALERT);
 748         if (!hdr)
 749                 return -EMSGSIZE;
 750
 751         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
 752                 goto nla_put_failure;
 753
 754         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
 755                            hw_metadata->trap_group_name))
 756                 goto nla_put_failure;
 757
 758         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
 759                            hw_metadata->trap_name))
 760                 goto nla_put_failure;
 761
 762         if (hw_metadata->input_dev) {
 763                 struct net_device *dev = hw_metadata->input_dev;
 764                 int rc;
 765
 766                 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
 767                                                       dev->name);
 768                 if (rc)
 769                         goto nla_put_failure;
 770         }
 771
 772         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 773                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 774                 goto nla_put_failure;
 775
 776         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 777                 goto nla_put_failure;
 778
 779         if (!payload_len)
 780                 goto out;
 781
 782         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 783                 goto nla_put_failure;
 784
 785         attr = skb_put(msg, nla_total_size(payload_len));
 786         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 787         attr->nla_len = nla_attr_size(payload_len);
 788         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 789                 goto nla_put_failure;
 790
 791 out:
 792         genlmsg_end(msg, hdr);
 793
 794         return 0;
 795
 796 nla_put_failure:
 797         genlmsg_cancel(msg, hdr);
 798         return -EMSGSIZE;
 799 }
 800
 801 static struct net_dm_hw_metadata *
 802 net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata)
 803 {
 804         struct net_dm_hw_metadata *n_hw_metadata;
 805         const char *trap_group_name;
 806         const char *trap_name;
 807
 808         n_hw_metadata = kmalloc(sizeof(*hw_metadata), GFP_ATOMIC);
 809         if (!n_hw_metadata)
 810                 return NULL;
 811
 812         trap_group_name = kmemdup(hw_metadata->trap_group_name,
 813                                   strlen(hw_metadata->trap_group_name) + 1,
 814                                   GFP_ATOMIC | __GFP_ZERO);
 815         if (!trap_group_name)
 816                 goto free_hw_metadata;
 817         n_hw_metadata->trap_group_name = trap_group_name;
 818
 819         trap_name = kmemdup(hw_metadata->trap_name,
 820                             strlen(hw_metadata->trap_name) + 1,
 821                             GFP_ATOMIC | __GFP_ZERO);
 822         if (!trap_name)
 823                 goto free_trap_group;
 824         n_hw_metadata->trap_name = trap_name;
 825
 826         n_hw_metadata->input_dev = hw_metadata->input_dev;
 827         if (n_hw_metadata->input_dev)
 828                 dev_hold(n_hw_metadata->input_dev);
 829
 830         return n_hw_metadata;
 831
 832 free_trap_group:
 833         kfree(trap_group_name);
 834 free_hw_metadata:
 835         kfree(n_hw_metadata);
 836         return NULL;
 837 }
 838
 839 static void
 840 net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata)
 841 {
 842         if (hw_metadata->input_dev)
 843                 dev_put(hw_metadata->input_dev);
 844         kfree(hw_metadata->trap_name);
 845         kfree(hw_metadata->trap_group_name);
 846         kfree(hw_metadata);
 847 }
 848
 849 static void net_dm_hw_packet_report(struct sk_buff *skb)
 850 {
 851         struct net_dm_hw_metadata *hw_metadata;
 852         struct sk_buff *msg;
 853         size_t payload_len;
 854         int rc;
 855
 856         if (skb->data > skb_mac_header(skb))
 857                 skb_push(skb, skb->data - skb_mac_header(skb));
 858         else
 859                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 860
 861         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 862         if (net_dm_trunc_len)
 863                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 864
 865         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 866         msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
 867                         GFP_KERNEL);
 868         if (!msg)
 869                 goto out;
 870
 871         rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
 872         if (rc) {
 873                 nlmsg_free(msg);
 874                 goto out;
 875         }
 876
 877         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 878
 879 out:
 880         net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 881         consume_skb(skb);
 882 }
 883
 884 static void net_dm_hw_packet_work(struct work_struct *work)
 885 {
 886         struct per_cpu_dm_data *hw_data;
 887         struct sk_buff_head list;
 888         struct sk_buff *skb;
 889         unsigned long flags;
 890
 891         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 892
 893         __skb_queue_head_init(&list);
 894
 895         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 896         skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
 897         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 898
 899         while ((skb = __skb_dequeue(&list)))
 900                 net_dm_hw_packet_report(skb);
 901 }
 902
 903 static void
 904 net_dm_hw_packet_probe(struct sk_buff *skb,
 905                        const struct net_dm_hw_metadata *hw_metadata)
 906 {
 907         struct net_dm_hw_metadata *n_hw_metadata;
 908         ktime_t tstamp = ktime_get_real();
 909         struct per_cpu_dm_data *hw_data;
 910         struct sk_buff *nskb;
 911         unsigned long flags;
 912
 913         if (!skb_mac_header_was_set(skb))
 914                 return;
 915
 916         nskb = skb_clone(skb, GFP_ATOMIC);
 917         if (!nskb)
 918                 return;
 919
 920         n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata);
 921         if (!n_hw_metadata)
 922                 goto free;
 923
 924         NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
 925         nskb->tstamp = tstamp;
 926
 927         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 928
 929         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 930         if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
 931                 __skb_queue_tail(&hw_data->drop_queue, nskb);
 932         else
 933                 goto unlock_free;
 934         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 935
 936         schedule_work(&hw_data->dm_alert_work);
 937
 938         return;
 939
 940 unlock_free:
 941         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 942         u64_stats_update_begin(&hw_data->stats.syncp);
 943         hw_data->stats.dropped++;
 944         u64_stats_update_end(&hw_data->stats.syncp);
 945         net_dm_hw_metadata_free(n_hw_metadata);
 946 free:
 947         consume_skb(nskb);
 948 }
 949
 950 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
 951         .kfree_skb_probe        = net_dm_packet_trace_kfree_skb_hit,
 952         .napi_poll_probe        = net_dm_packet_trace_napi_poll_hit,
 953         .work_item_func         = net_dm_packet_work,
 954         .hw_work_item_func      = net_dm_hw_packet_work,
 955         .hw_probe               = net_dm_hw_packet_probe,
 956 };
 957
 958 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
 959         [NET_DM_ALERT_MODE_SUMMARY]     = &net_dm_alert_summary_ops,
 960         [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
 961 };
 962
 963 void net_dm_hw_report(struct sk_buff *skb,
 964                       const struct net_dm_hw_metadata *hw_metadata)
 965 {
 966         rcu_read_lock();
 967
 968         if (!monitor_hw)
 969                 goto out;
 970
 971         net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata);
 972
 973 out:
 974         rcu_read_unlock();
 975 }
 976 EXPORT_SYMBOL_GPL(net_dm_hw_report);
 977
 978 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
 979 {
 980         const struct net_dm_alert_ops *ops;
 981         int cpu;
 982
 983         if (monitor_hw) {
 984                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
 985                 return -EAGAIN;
 986         }
 987
 988         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
 989
 990         if (!try_module_get(THIS_MODULE)) {
 991                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
 992                 return -ENODEV;
 993         }
 994
 995         for_each_possible_cpu(cpu) {
 996                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
 997                 struct net_dm_hw_entries *hw_entries;
 998
 999                 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1000                 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1001                 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1002                 kfree(hw_entries);
1003         }
1004
1005         monitor_hw = true;
1006
1007         return 0;
1008 }
1009
1010 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1011 {
1012         int cpu;
1013
1014         if (!monitor_hw) {
1015                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1016                 return;
1017         }
1018
1019         monitor_hw = false;
1020
1021         /* After this call returns we are guaranteed that no CPU is processing
1022          * any hardware drops.
1023          */
1024         synchronize_rcu();
1025
1026         for_each_possible_cpu(cpu) {
1027                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1028                 struct sk_buff *skb;
1029
1030                 del_timer_sync(&hw_data->send_timer);
1031                 cancel_work_sync(&hw_data->dm_alert_work);
1032                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1033                         struct net_dm_hw_metadata *hw_metadata;
1034
1035                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1036                         net_dm_hw_metadata_free(hw_metadata);
1037                         consume_skb(skb);
1038                 }
1039         }
1040
1041         module_put(THIS_MODULE);
1042 }
1043
1044 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1045 {
1046         const struct net_dm_alert_ops *ops;
1047         int cpu, rc;
1048
1049         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1050
1051         if (!try_module_get(THIS_MODULE)) {
1052                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1053                 return -ENODEV;
1054         }
1055
1056         for_each_possible_cpu(cpu) {
1057                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1058                 struct sk_buff *skb;
1059
1060                 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1061                 timer_setup(&data->send_timer, sched_send_work, 0);
1062                 /* Allocate a new per-CPU skb for the summary alert message and
1063                  * free the old one which might contain stale data from
1064                  * previous tracing.
1065                  */
1066                 skb = reset_per_cpu_data(data);
1067                 consume_skb(skb);
1068         }
1069
1070         rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1071         if (rc) {
1072                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1073                 goto err_module_put;
1074         }
1075
1076         rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1077         if (rc) {
1078                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1079                 goto err_unregister_trace;
1080         }
1081
1082         return 0;
1083
1084 err_unregister_trace:
1085         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1086 err_module_put:
1087         module_put(THIS_MODULE);
1088         return rc;
1089 }
1090
1091 static void net_dm_trace_off_set(void)
1092 {
1093         struct dm_hw_stat_delta *new_stat, *temp;
1094         const struct net_dm_alert_ops *ops;
1095         int cpu;
1096
1097         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1098
1099         unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1100         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1101
1102         tracepoint_synchronize_unregister();
1103
1104         /* Make sure we do not send notifications to user space after request
1105          * to stop tracing returns.
1106          */
1107         for_each_possible_cpu(cpu) {
1108                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1109                 struct sk_buff *skb;
1110
1111                 del_timer_sync(&data->send_timer);
1112                 cancel_work_sync(&data->dm_alert_work);
1113                 while ((skb = __skb_dequeue(&data->drop_queue)))
1114                         consume_skb(skb);
1115         }
1116
1117         list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
1118                 if (new_stat->dev == NULL) {
1119                         list_del_rcu(&new_stat->list);
1120                         kfree_rcu(new_stat, rcu);
1121                 }
1122         }
1123
1124         module_put(THIS_MODULE);
1125 }
1126
1127 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1128 {
1129         int rc = 0;
1130
1131         if (state == trace_state) {
1132                 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1133                 return -EAGAIN;
1134         }
1135
1136         switch (state) {
1137         case TRACE_ON:
1138                 rc = net_dm_trace_on_set(extack);
1139                 break;
1140         case TRACE_OFF:
1141                 net_dm_trace_off_set();
1142                 break;
1143         default:
1144                 rc = 1;
1145                 break;
1146         }
1147
1148         if (!rc)
1149                 trace_state = state;
1150         else
1151                 rc = -EINPROGRESS;
1152
1153         return rc;
1154 }
1155
1156 static bool net_dm_is_monitoring(void)
1157 {
1158         return trace_state == TRACE_ON || monitor_hw;
1159 }
1160
1161 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1162                                            enum net_dm_alert_mode *p_alert_mode)
1163 {
1164         u8 val;
1165
1166         val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1167
1168         switch (val) {
1169         case NET_DM_ALERT_MODE_SUMMARY: /* fall-through */
1170         case NET_DM_ALERT_MODE_PACKET:
1171                 *p_alert_mode = val;
1172                 break;
1173         default:
1174                 return -EINVAL;
1175         }
1176
1177         return 0;
1178 }
1179
1180 static int net_dm_alert_mode_set(struct genl_info *info)
1181 {
1182         struct netlink_ext_ack *extack = info->extack;
1183         enum net_dm_alert_mode alert_mode;
1184         int rc;
1185
1186         if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1187                 return 0;
1188
1189         rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1190         if (rc) {
1191                 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1192                 return -EINVAL;
1193         }
1194
1195         net_dm_alert_mode = alert_mode;
1196
1197         return 0;
1198 }
1199
1200 static void net_dm_trunc_len_set(struct genl_info *info)
1201 {
1202         if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1203                 return;
1204
1205         net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1206 }
1207
1208 static void net_dm_queue_len_set(struct genl_info *info)
1209 {
1210         if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1211                 return;
1212
1213         net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1214 }
1215
1216 static int net_dm_cmd_config(struct sk_buff *skb,
1217                         struct genl_info *info)
1218 {
1219         struct netlink_ext_ack *extack = info->extack;
1220         int rc;
1221
1222         if (net_dm_is_monitoring()) {
1223                 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1224                 return -EBUSY;
1225         }
1226
1227         rc = net_dm_alert_mode_set(info);
1228         if (rc)
1229                 return rc;
1230
1231         net_dm_trunc_len_set(info);
1232
1233         net_dm_queue_len_set(info);
1234
1235         return 0;
1236 }
1237
1238 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1239                                 struct netlink_ext_ack *extack)
1240 {
1241         bool sw_set = false;
1242         int rc;
1243
1244         if (set_sw) {
1245                 rc = set_all_monitor_traces(TRACE_ON, extack);
1246                 if (rc)
1247                         return rc;
1248                 sw_set = true;
1249         }
1250
1251         if (set_hw) {
1252                 rc = net_dm_hw_monitor_start(extack);
1253                 if (rc)
1254                         goto err_monitor_hw;
1255         }
1256
1257         return 0;
1258
1259 err_monitor_hw:
1260         if (sw_set)
1261                 set_all_monitor_traces(TRACE_OFF, extack);
1262         return rc;
1263 }
1264
1265 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1266                                 struct netlink_ext_ack *extack)
1267 {
1268         if (set_hw)
1269                 net_dm_hw_monitor_stop(extack);
1270         if (set_sw)
1271                 set_all_monitor_traces(TRACE_OFF, extack);
1272 }
1273
1274 static int net_dm_cmd_trace(struct sk_buff *skb,
1275                         struct genl_info *info)
1276 {
1277         bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1278         bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1279         struct netlink_ext_ack *extack = info->extack;
1280
1281         /* To maintain backward compatibility, we start / stop monitoring of
1282          * software drops if no flag is specified.
1283          */
1284         if (!set_sw && !set_hw)
1285                 set_sw = true;
1286
1287         switch (info->genlhdr->cmd) {
1288         case NET_DM_CMD_START:
1289                 return net_dm_monitor_start(set_sw, set_hw, extack);
1290         case NET_DM_CMD_STOP:
1291                 net_dm_monitor_stop(set_sw, set_hw, extack);
1292                 return 0;
1293         }
1294
1295         return -EOPNOTSUPP;
1296 }
1297
1298 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1299 {
1300         void *hdr;
1301
1302         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1303                           &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1304         if (!hdr)
1305                 return -EMSGSIZE;
1306
1307         if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1308                 goto nla_put_failure;
1309
1310         if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1311                 goto nla_put_failure;
1312
1313         if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1314                 goto nla_put_failure;
1315
1316         genlmsg_end(msg, hdr);
1317
1318         return 0;
1319
1320 nla_put_failure:
1321         genlmsg_cancel(msg, hdr);
1322         return -EMSGSIZE;
1323 }
1324
1325 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1326 {
1327         struct sk_buff *msg;
1328         int rc;
1329
1330         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1331         if (!msg)
1332                 return -ENOMEM;
1333
1334         rc = net_dm_config_fill(msg, info);
1335         if (rc)
1336                 goto free_msg;
1337
1338         return genlmsg_reply(msg, info);
1339
1340 free_msg:
1341         nlmsg_free(msg);
1342         return rc;
1343 }
1344
1345 static void net_dm_stats_read(struct net_dm_stats *stats)
1346 {
1347         int cpu;
1348
1349         memset(stats, 0, sizeof(*stats));
1350         for_each_possible_cpu(cpu) {
1351                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1352                 struct net_dm_stats *cpu_stats = &data->stats;
1353                 unsigned int start;
1354                 u64 dropped;
1355
1356                 do {
1357                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1358                         dropped = cpu_stats->dropped;
1359                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1360
1361                 stats->dropped += dropped;
1362         }
1363 }
1364
1365 static int net_dm_stats_put(struct sk_buff *msg)
1366 {
1367         struct net_dm_stats stats;
1368         struct nlattr *attr;
1369
1370         net_dm_stats_read(&stats);
1371
1372         attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1373         if (!attr)
1374                 return -EMSGSIZE;
1375
1376         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1377                               stats.dropped, NET_DM_ATTR_PAD))
1378                 goto nla_put_failure;
1379
1380         nla_nest_end(msg, attr);
1381
1382         return 0;
1383
1384 nla_put_failure:
1385         nla_nest_cancel(msg, attr);
1386         return -EMSGSIZE;
1387 }
1388
1389 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1390 {
1391         int cpu;
1392
1393         memset(stats, 0, sizeof(*stats));
1394         for_each_possible_cpu(cpu) {
1395                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1396                 struct net_dm_stats *cpu_stats = &hw_data->stats;
1397                 unsigned int start;
1398                 u64 dropped;
1399
1400                 do {
1401                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1402                         dropped = cpu_stats->dropped;
1403                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1404
1405                 stats->dropped += dropped;
1406         }
1407 }
1408
1409 static int net_dm_hw_stats_put(struct sk_buff *msg)
1410 {
1411         struct net_dm_stats stats;
1412         struct nlattr *attr;
1413
1414         net_dm_hw_stats_read(&stats);
1415
1416         attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1417         if (!attr)
1418                 return -EMSGSIZE;
1419
1420         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1421                               stats.dropped, NET_DM_ATTR_PAD))
1422                 goto nla_put_failure;
1423
1424         nla_nest_end(msg, attr);
1425
1426         return 0;
1427
1428 nla_put_failure:
1429         nla_nest_cancel(msg, attr);
1430         return -EMSGSIZE;
1431 }
1432
1433 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1434 {
1435         void *hdr;
1436         int rc;
1437
1438         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1439                           &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1440         if (!hdr)
1441                 return -EMSGSIZE;
1442
1443         rc = net_dm_stats_put(msg);
1444         if (rc)
1445                 goto nla_put_failure;
1446
1447         rc = net_dm_hw_stats_put(msg);
1448         if (rc)
1449                 goto nla_put_failure;
1450
1451         genlmsg_end(msg, hdr);
1452
1453         return 0;
1454
1455 nla_put_failure:
1456         genlmsg_cancel(msg, hdr);
1457         return -EMSGSIZE;
1458 }
1459
1460 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1461 {
1462         struct sk_buff *msg;
1463         int rc;
1464
1465         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1466         if (!msg)
1467                 return -ENOMEM;
1468
1469         rc = net_dm_stats_fill(msg, info);
1470         if (rc)
1471                 goto free_msg;
1472
1473         return genlmsg_reply(msg, info);
1474
1475 free_msg:
1476         nlmsg_free(msg);
1477         return rc;
1478 }
1479
1480 static int dropmon_net_event(struct notifier_block *ev_block,
1481                              unsigned long event, void *ptr)
1482 {
1483         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1484         struct dm_hw_stat_delta *new_stat = NULL;
1485         struct dm_hw_stat_delta *tmp;
1486
1487         switch (event) {
1488         case NETDEV_REGISTER:
1489                 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
1490
1491                 if (!new_stat)
1492                         goto out;
1493
1494                 new_stat->dev = dev;
1495                 new_stat->last_rx = jiffies;
1496                 mutex_lock(&net_dm_mutex);
1497                 list_add_rcu(&new_stat->list, &hw_stats_list);
1498                 mutex_unlock(&net_dm_mutex);
1499                 break;
1500         case NETDEV_UNREGISTER:
1501                 mutex_lock(&net_dm_mutex);
1502                 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
1503                         if (new_stat->dev == dev) {
1504
1505                                 /* Paired with READ_ONCE() in trace_napi_poll_hit() */
1506                                 WRITE_ONCE(new_stat->dev, NULL);
1507
1508                                 if (trace_state == TRACE_OFF) {
1509                                         list_del_rcu(&new_stat->list);
1510                                         kfree_rcu(new_stat, rcu);
1511                                         break;
1512                                 }
1513                         }
1514                 }
1515                 mutex_unlock(&net_dm_mutex);
1516                 break;
1517         }
1518 out:
1519         return NOTIFY_DONE;
1520 }
1521
1522 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1523         [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1524         [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1525         [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1526         [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1527         [NET_DM_ATTR_SW_DROPS]  = {. type = NLA_FLAG },
1528         [NET_DM_ATTR_HW_DROPS]  = {. type = NLA_FLAG },
1529 };
1530
1531 static const struct genl_ops dropmon_ops[] = {
1532         {
1533                 .cmd = NET_DM_CMD_CONFIG,
1534                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1535                 .doit = net_dm_cmd_config,
1536                 .flags = GENL_ADMIN_PERM,
1537         },
1538         {
1539                 .cmd = NET_DM_CMD_START,
1540                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1541                 .doit = net_dm_cmd_trace,
1542         },
1543         {
1544                 .cmd = NET_DM_CMD_STOP,
1545                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1546                 .doit = net_dm_cmd_trace,
1547         },
1548         {
1549                 .cmd = NET_DM_CMD_CONFIG_GET,
1550                 .doit = net_dm_cmd_config_get,
1551         },
1552         {
1553                 .cmd = NET_DM_CMD_STATS_GET,
1554                 .doit = net_dm_cmd_stats_get,
1555         },
1556 };
1557
1558 static int net_dm_nl_pre_doit(const struct genl_ops *ops,
1559                               struct sk_buff *skb, struct genl_info *info)
1560 {
1561         mutex_lock(&net_dm_mutex);
1562
1563         return 0;
1564 }
1565
1566 static void net_dm_nl_post_doit(const struct genl_ops *ops,
1567                                 struct sk_buff *skb, struct genl_info *info)
1568 {
1569         mutex_unlock(&net_dm_mutex);
1570 }
1571
1572 static struct genl_family net_drop_monitor_family __ro_after_init = {
1573         .hdrsize        = 0,
1574         .name           = "NET_DM",
1575         .version        = 2,
1576         .maxattr        = NET_DM_ATTR_MAX,
1577         .policy         = net_dm_nl_policy,
1578         .pre_doit       = net_dm_nl_pre_doit,
1579         .post_doit      = net_dm_nl_post_doit,
1580         .module         = THIS_MODULE,
1581         .ops            = dropmon_ops,
1582         .n_ops          = ARRAY_SIZE(dropmon_ops),
1583         .mcgrps         = dropmon_mcgrps,
1584         .n_mcgrps       = ARRAY_SIZE(dropmon_mcgrps),
1585 };
1586
1587 static struct notifier_block dropmon_net_notifier = {
1588         .notifier_call = dropmon_net_event
1589 };
1590
1591 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1592 {
1593         spin_lock_init(&data->lock);
1594         skb_queue_head_init(&data->drop_queue);
1595         u64_stats_init(&data->stats.syncp);
1596 }
1597
1598 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1599 {
1600         WARN_ON(!skb_queue_empty(&data->drop_queue));
1601 }
1602
1603 static void net_dm_cpu_data_init(int cpu)
1604 {
1605         struct per_cpu_dm_data *data;
1606
1607         data = &per_cpu(dm_cpu_data, cpu);
1608         __net_dm_cpu_data_init(data);
1609 }
1610
1611 static void net_dm_cpu_data_fini(int cpu)
1612 {
1613         struct per_cpu_dm_data *data;
1614
1615         data = &per_cpu(dm_cpu_data, cpu);
1616         /* At this point, we should have exclusive access
1617          * to this struct and can free the skb inside it.
1618          */
1619         consume_skb(data->skb);
1620         __net_dm_cpu_data_fini(data);
1621 }
1622
1623 static void net_dm_hw_cpu_data_init(int cpu)
1624 {
1625         struct per_cpu_dm_data *hw_data;
1626
1627         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1628         __net_dm_cpu_data_init(hw_data);
1629 }
1630
1631 static void net_dm_hw_cpu_data_fini(int cpu)
1632 {
1633         struct per_cpu_dm_data *hw_data;
1634
1635         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1636         kfree(hw_data->hw_entries);
1637         __net_dm_cpu_data_fini(hw_data);
1638 }
1639
1640 static int __init init_net_drop_monitor(void)
1641 {
1642         int cpu, rc;
1643
1644         pr_info("Initializing network drop monitor service\n");
1645
1646         if (sizeof(void *) > 8) {
1647                 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1648                 return -ENOSPC;
1649         }
1650
1651         rc = genl_register_family(&net_drop_monitor_family);
1652         if (rc) {
1653                 pr_err("Could not create drop monitor netlink family\n");
1654                 return rc;
1655         }
1656         WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1657
1658         rc = register_netdevice_notifier(&dropmon_net_notifier);
1659         if (rc < 0) {
1660                 pr_crit("Failed to register netdevice notifier\n");
1661                 goto out_unreg;
1662         }
1663
1664         rc = 0;
1665
1666         for_each_possible_cpu(cpu) {
1667                 net_dm_cpu_data_init(cpu);
1668                 net_dm_hw_cpu_data_init(cpu);
1669         }
1670
1671         goto out;
1672
1673 out_unreg:
1674         genl_unregister_family(&net_drop_monitor_family);
1675 out:
1676         return rc;
1677 }
1678
1679 static void exit_net_drop_monitor(void)
1680 {
1681         int cpu;
1682
1683         BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1684
1685         /*
1686          * Because of the module_get/put we do in the trace state change path
1687          * we are guarnateed not to have any current users when we get here
1688          */
1689
1690         for_each_possible_cpu(cpu) {
1691                 net_dm_hw_cpu_data_fini(cpu);
1692                 net_dm_cpu_data_fini(cpu);
1693         }
1694
1695         BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1696 }
1697
1698 module_init(init_net_drop_monitor);
1699 module_exit(exit_net_drop_monitor);
1700
1701 MODULE_LICENSE("GPL v2");
1702 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1703 MODULE_ALIAS_GENL_FAMILY("NET_DM");