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/genetlink.h>
  30 #include <net/netevent.h>
  31 #include <net/flow_offload.h>
  32 #include <net/devlink.h>
  33
  34 #include <trace/events/skb.h>
  35 #include <trace/events/napi.h>
  36 #include <trace/events/devlink.h>
  37
  38 #include <asm/unaligned.h>
  39
  40 #define TRACE_ON 1
  41 #define TRACE_OFF 0
  42
  43 /*
  44  * Globals, our netlink socket pointer
  45  * and the work handle that will send up
  46  * netlink alerts
  47  */
  48 static int trace_state = TRACE_OFF;
  49 static bool monitor_hw;
  50
  51 /* net_dm_mutex
  52  *
  53  * An overall lock guarding every operation coming from userspace.
  54  * It also guards the global 'hw_stats_list' list.
  55  */
  56 static DEFINE_MUTEX(net_dm_mutex);
  57
  58 struct net_dm_stats {
  59         u64 dropped;
  60         struct u64_stats_sync syncp;
  61 };
  62
  63 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
  64
  65 struct net_dm_hw_entry {
  66         char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  67         u32 count;
  68 };
  69
  70 struct net_dm_hw_entries {
  71         u32 num_entries;
  72         struct net_dm_hw_entry entries[];
  73 };
  74
  75 struct per_cpu_dm_data {
  76         spinlock_t              lock;   /* Protects 'skb', 'hw_entries' and
  77                                          * 'send_timer'
  78                                          */
  79         union {
  80                 struct sk_buff                  *skb;
  81                 struct net_dm_hw_entries        *hw_entries;
  82         };
  83         struct sk_buff_head     drop_queue;
  84         struct work_struct      dm_alert_work;
  85         struct timer_list       send_timer;
  86         struct net_dm_stats     stats;
  87 };
  88
  89 struct dm_hw_stat_delta {
  90         struct net_device *dev;
  91         unsigned long last_rx;
  92         struct list_head list;
  93         struct rcu_head rcu;
  94         unsigned long last_drop_val;
  95 };
  96
  97 static struct genl_family net_drop_monitor_family;
  98
  99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
 100 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 101
 102 static int dm_hit_limit = 64;
 103 static int dm_delay = 1;
 104 static unsigned long dm_hw_check_delta = 2*HZ;
 105 static LIST_HEAD(hw_stats_list);
 106
 107 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 108 static u32 net_dm_trunc_len;
 109 static u32 net_dm_queue_len = 1000;
 110
 111 struct net_dm_alert_ops {
 112         void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
 113                                 void *location);
 114         void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 115                                 int work, int budget);
 116         void (*work_item_func)(struct work_struct *work);
 117         void (*hw_work_item_func)(struct work_struct *work);
 118         void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
 119                               struct sk_buff *skb,
 120                               const struct devlink_trap_metadata *metadata);
 121 };
 122
 123 struct net_dm_skb_cb {
 124         union {
 125                 struct devlink_trap_metadata *hw_metadata;
 126                 void *pc;
 127         };
 128 };
 129
 130 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
 131
 132 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 133 {
 134         size_t al;
 135         struct net_dm_alert_msg *msg;
 136         struct nlattr *nla;
 137         struct sk_buff *skb;
 138         unsigned long flags;
 139         void *msg_header;
 140
 141         al = sizeof(struct net_dm_alert_msg);
 142         al += dm_hit_limit * sizeof(struct net_dm_drop_point);
 143         al += sizeof(struct nlattr);
 144
 145         skb = genlmsg_new(al, GFP_KERNEL);
 146
 147         if (!skb)
 148                 goto err;
 149
 150         msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
 151                                  0, NET_DM_CMD_ALERT);
 152         if (!msg_header) {
 153                 nlmsg_free(skb);
 154                 skb = NULL;
 155                 goto err;
 156         }
 157         nla = nla_reserve(skb, NLA_UNSPEC,
 158                           sizeof(struct net_dm_alert_msg));
 159         if (!nla) {
 160                 nlmsg_free(skb);
 161                 skb = NULL;
 162                 goto err;
 163         }
 164         msg = nla_data(nla);
 165         memset(msg, 0, al);
 166         goto out;
 167
 168 err:
 169         mod_timer(&data->send_timer, jiffies + HZ / 10);
 170 out:
 171         spin_lock_irqsave(&data->lock, flags);
 172         swap(data->skb, skb);
 173         spin_unlock_irqrestore(&data->lock, flags);
 174
 175         if (skb) {
 176                 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
 177                 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
 178
 179                 genlmsg_end(skb, genlmsg_data(gnlh));
 180         }
 181
 182         return skb;
 183 }
 184
 185 static const struct genl_multicast_group dropmon_mcgrps[] = {
 186         { .name = "events", },
 187 };
 188
 189 static void send_dm_alert(struct work_struct *work)
 190 {
 191         struct sk_buff *skb;
 192         struct per_cpu_dm_data *data;
 193
 194         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 195
 196         skb = reset_per_cpu_data(data);
 197
 198         if (skb)
 199                 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
 200                                   0, GFP_KERNEL);
 201 }
 202
 203 /*
 204  * This is the timer function to delay the sending of an alert
 205  * in the event that more drops will arrive during the
 206  * hysteresis period.
 207  */
 208 static void sched_send_work(struct timer_list *t)
 209 {
 210         struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
 211
 212         schedule_work(&data->dm_alert_work);
 213 }
 214
 215 static void trace_drop_common(struct sk_buff *skb, void *location)
 216 {
 217         struct net_dm_alert_msg *msg;
 218         struct net_dm_drop_point *point;
 219         struct nlmsghdr *nlh;
 220         struct nlattr *nla;
 221         int i;
 222         struct sk_buff *dskb;
 223         struct per_cpu_dm_data *data;
 224         unsigned long flags;
 225
 226         local_irq_save(flags);
 227         data = this_cpu_ptr(&dm_cpu_data);
 228         spin_lock(&data->lock);
 229         dskb = data->skb;
 230
 231         if (!dskb)
 232                 goto out;
 233
 234         nlh = (struct nlmsghdr *)dskb->data;
 235         nla = genlmsg_data(nlmsg_data(nlh));
 236         msg = nla_data(nla);
 237         point = msg->points;
 238         for (i = 0; i < msg->entries; i++) {
 239                 if (!memcmp(&location, &point->pc, sizeof(void *))) {
 240                         point->count++;
 241                         goto out;
 242                 }
 243                 point++;
 244         }
 245         if (msg->entries == dm_hit_limit)
 246                 goto out;
 247         /*
 248          * We need to create a new entry
 249          */
 250         __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
 251         nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
 252         memcpy(point->pc, &location, sizeof(void *));
 253         point->count = 1;
 254         msg->entries++;
 255
 256         if (!timer_pending(&data->send_timer)) {
 257                 data->send_timer.expires = jiffies + dm_delay * HZ;
 258                 add_timer(&data->send_timer);
 259         }
 260
 261 out:
 262         spin_unlock_irqrestore(&data->lock, flags);
 263 }
 264
 265 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
 266 {
 267         trace_drop_common(skb, location);
 268 }
 269
 270 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 271                                 int work, int budget)
 272 {
 273         struct dm_hw_stat_delta *new_stat;
 274
 275         /*
 276          * Don't check napi structures with no associated device
 277          */
 278         if (!napi->dev)
 279                 return;
 280
 281         rcu_read_lock();
 282         list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
 283                 struct net_device *dev;
 284
 285                 /*
 286                  * only add a note to our monitor buffer if:
 287                  * 1) this is the dev we received on
 288                  * 2) its after the last_rx delta
 289                  * 3) our rx_dropped count has gone up
 290                  */
 291                 /* Paired with WRITE_ONCE() in dropmon_net_event() */
 292                 dev = READ_ONCE(new_stat->dev);
 293                 if ((dev == napi->dev)  &&
 294                     (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
 295                     (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
 296                         trace_drop_common(NULL, NULL);
 297                         new_stat->last_drop_val = napi->dev->stats.rx_dropped;
 298                         new_stat->last_rx = jiffies;
 299                         break;
 300                 }
 301         }
 302         rcu_read_unlock();
 303 }
 304
 305 static struct net_dm_hw_entries *
 306 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 307 {
 308         struct net_dm_hw_entries *hw_entries;
 309         unsigned long flags;
 310
 311         hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
 312                              GFP_KERNEL);
 313         if (!hw_entries) {
 314                 /* If the memory allocation failed, we try to perform another
 315                  * allocation in 1/10 second. Otherwise, the probe function
 316                  * will constantly bail out.
 317                  */
 318                 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 319         }
 320
 321         spin_lock_irqsave(&hw_data->lock, flags);
 322         swap(hw_data->hw_entries, hw_entries);
 323         spin_unlock_irqrestore(&hw_data->lock, flags);
 324
 325         return hw_entries;
 326 }
 327
 328 static int net_dm_hw_entry_put(struct sk_buff *msg,
 329                                const struct net_dm_hw_entry *hw_entry)
 330 {
 331         struct nlattr *attr;
 332
 333         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
 334         if (!attr)
 335                 return -EMSGSIZE;
 336
 337         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
 338                 goto nla_put_failure;
 339
 340         if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
 341                 goto nla_put_failure;
 342
 343         nla_nest_end(msg, attr);
 344
 345         return 0;
 346
 347 nla_put_failure:
 348         nla_nest_cancel(msg, attr);
 349         return -EMSGSIZE;
 350 }
 351
 352 static int net_dm_hw_entries_put(struct sk_buff *msg,
 353                                  const struct net_dm_hw_entries *hw_entries)
 354 {
 355         struct nlattr *attr;
 356         int i;
 357
 358         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
 359         if (!attr)
 360                 return -EMSGSIZE;
 361
 362         for (i = 0; i < hw_entries->num_entries; i++) {
 363                 int rc;
 364
 365                 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
 366                 if (rc)
 367                         goto nla_put_failure;
 368         }
 369
 370         nla_nest_end(msg, attr);
 371
 372         return 0;
 373
 374 nla_put_failure:
 375         nla_nest_cancel(msg, attr);
 376         return -EMSGSIZE;
 377 }
 378
 379 static int
 380 net_dm_hw_summary_report_fill(struct sk_buff *msg,
 381                               const struct net_dm_hw_entries *hw_entries)
 382 {
 383         struct net_dm_alert_msg anc_hdr = { 0 };
 384         void *hdr;
 385         int rc;
 386
 387         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 388                           NET_DM_CMD_ALERT);
 389         if (!hdr)
 390                 return -EMSGSIZE;
 391
 392         /* We need to put the ancillary header in order not to break user
 393          * space.
 394          */
 395         if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
 396                 goto nla_put_failure;
 397
 398         rc = net_dm_hw_entries_put(msg, hw_entries);
 399         if (rc)
 400                 goto nla_put_failure;
 401
 402         genlmsg_end(msg, hdr);
 403
 404         return 0;
 405
 406 nla_put_failure:
 407         genlmsg_cancel(msg, hdr);
 408         return -EMSGSIZE;
 409 }
 410
 411 static void net_dm_hw_summary_work(struct work_struct *work)
 412 {
 413         struct net_dm_hw_entries *hw_entries;
 414         struct per_cpu_dm_data *hw_data;
 415         struct sk_buff *msg;
 416         int rc;
 417
 418         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 419
 420         hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
 421         if (!hw_entries)
 422                 return;
 423
 424         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 425         if (!msg)
 426                 goto out;
 427
 428         rc = net_dm_hw_summary_report_fill(msg, hw_entries);
 429         if (rc) {
 430                 nlmsg_free(msg);
 431                 goto out;
 432         }
 433
 434         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 435
 436 out:
 437         kfree(hw_entries);
 438 }
 439
 440 static void
 441 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
 442                              struct sk_buff *skb,
 443                              const struct devlink_trap_metadata *metadata)
 444 {
 445         struct net_dm_hw_entries *hw_entries;
 446         struct net_dm_hw_entry *hw_entry;
 447         struct per_cpu_dm_data *hw_data;
 448         unsigned long flags;
 449         int i;
 450
 451         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 452                 return;
 453
 454         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 455         spin_lock_irqsave(&hw_data->lock, flags);
 456         hw_entries = hw_data->hw_entries;
 457
 458         if (!hw_entries)
 459                 goto out;
 460
 461         for (i = 0; i < hw_entries->num_entries; i++) {
 462                 hw_entry = &hw_entries->entries[i];
 463                 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
 464                              NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
 465                         hw_entry->count++;
 466                         goto out;
 467                 }
 468         }
 469         if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
 470                 goto out;
 471
 472         hw_entry = &hw_entries->entries[hw_entries->num_entries];
 473         strlcpy(hw_entry->trap_name, metadata->trap_name,
 474                 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
 475         hw_entry->count = 1;
 476         hw_entries->num_entries++;
 477
 478         if (!timer_pending(&hw_data->send_timer)) {
 479                 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
 480                 add_timer(&hw_data->send_timer);
 481         }
 482
 483 out:
 484         spin_unlock_irqrestore(&hw_data->lock, flags);
 485 }
 486
 487 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 488         .kfree_skb_probe        = trace_kfree_skb_hit,
 489         .napi_poll_probe        = trace_napi_poll_hit,
 490         .work_item_func         = send_dm_alert,
 491         .hw_work_item_func      = net_dm_hw_summary_work,
 492         .hw_trap_probe          = net_dm_hw_trap_summary_probe,
 493 };
 494
 495 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 496                                               struct sk_buff *skb,
 497                                               void *location)
 498 {
 499         ktime_t tstamp = ktime_get_real();
 500         struct per_cpu_dm_data *data;
 501         struct sk_buff *nskb;
 502         unsigned long flags;
 503
 504         if (!skb_mac_header_was_set(skb))
 505                 return;
 506
 507         nskb = skb_clone(skb, GFP_ATOMIC);
 508         if (!nskb)
 509                 return;
 510
 511         NET_DM_SKB_CB(nskb)->pc = location;
 512         /* Override the timestamp because we care about the time when the
 513          * packet was dropped.
 514          */
 515         nskb->tstamp = tstamp;
 516
 517         data = this_cpu_ptr(&dm_cpu_data);
 518
 519         spin_lock_irqsave(&data->drop_queue.lock, flags);
 520         if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
 521                 __skb_queue_tail(&data->drop_queue, nskb);
 522         else
 523                 goto unlock_free;
 524         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 525
 526         schedule_work(&data->dm_alert_work);
 527
 528         return;
 529
 530 unlock_free:
 531         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 532         u64_stats_update_begin(&data->stats.syncp);
 533         data->stats.dropped++;
 534         u64_stats_update_end(&data->stats.syncp);
 535         consume_skb(nskb);
 536 }
 537
 538 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
 539                                               struct napi_struct *napi,
 540                                               int work, int budget)
 541 {
 542 }
 543
 544 static size_t net_dm_in_port_size(void)
 545 {
 546                /* NET_DM_ATTR_IN_PORT nest */
 547         return nla_total_size(0) +
 548                /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
 549                nla_total_size(sizeof(u32)) +
 550                /* NET_DM_ATTR_PORT_NETDEV_NAME */
 551                nla_total_size(IFNAMSIZ + 1);
 552 }
 553
 554 #define NET_DM_MAX_SYMBOL_LEN 40
 555
 556 static size_t net_dm_packet_report_size(size_t payload_len)
 557 {
 558         size_t size;
 559
 560         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 561
 562         return NLMSG_ALIGN(size) +
 563                /* NET_DM_ATTR_ORIGIN */
 564                nla_total_size(sizeof(u16)) +
 565                /* NET_DM_ATTR_PC */
 566                nla_total_size(sizeof(u64)) +
 567                /* NET_DM_ATTR_SYMBOL */
 568                nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
 569                /* NET_DM_ATTR_IN_PORT */
 570                net_dm_in_port_size() +
 571                /* NET_DM_ATTR_TIMESTAMP */
 572                nla_total_size(sizeof(u64)) +
 573                /* NET_DM_ATTR_ORIG_LEN */
 574                nla_total_size(sizeof(u32)) +
 575                /* NET_DM_ATTR_PROTO */
 576                nla_total_size(sizeof(u16)) +
 577                /* NET_DM_ATTR_PAYLOAD */
 578                nla_total_size(payload_len);
 579 }
 580
 581 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
 582                                             const char *name)
 583 {
 584         struct nlattr *attr;
 585
 586         attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
 587         if (!attr)
 588                 return -EMSGSIZE;
 589
 590         if (ifindex &&
 591             nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
 592                 goto nla_put_failure;
 593
 594         if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
 595                 goto nla_put_failure;
 596
 597         nla_nest_end(msg, attr);
 598
 599         return 0;
 600
 601 nla_put_failure:
 602         nla_nest_cancel(msg, attr);
 603         return -EMSGSIZE;
 604 }
 605
 606 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
 607                                      size_t payload_len)
 608 {
 609         u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
 610         char buf[NET_DM_MAX_SYMBOL_LEN];
 611         struct nlattr *attr;
 612         void *hdr;
 613         int rc;
 614
 615         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 616                           NET_DM_CMD_PACKET_ALERT);
 617         if (!hdr)
 618                 return -EMSGSIZE;
 619
 620         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
 621                 goto nla_put_failure;
 622
 623         if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
 624                 goto nla_put_failure;
 625
 626         snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
 627         if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
 628                 goto nla_put_failure;
 629
 630         rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
 631         if (rc)
 632                 goto nla_put_failure;
 633
 634         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 635                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 636                 goto nla_put_failure;
 637
 638         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 639                 goto nla_put_failure;
 640
 641         if (!payload_len)
 642                 goto out;
 643
 644         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 645                 goto nla_put_failure;
 646
 647         attr = skb_put(msg, nla_total_size(payload_len));
 648         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 649         attr->nla_len = nla_attr_size(payload_len);
 650         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 651                 goto nla_put_failure;
 652
 653 out:
 654         genlmsg_end(msg, hdr);
 655
 656         return 0;
 657
 658 nla_put_failure:
 659         genlmsg_cancel(msg, hdr);
 660         return -EMSGSIZE;
 661 }
 662
 663 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
 664
 665 static void net_dm_packet_report(struct sk_buff *skb)
 666 {
 667         struct sk_buff *msg;
 668         size_t payload_len;
 669         int rc;
 670
 671         /* Make sure we start copying the packet from the MAC header */
 672         if (skb->data > skb_mac_header(skb))
 673                 skb_push(skb, skb->data - skb_mac_header(skb));
 674         else
 675                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 676
 677         /* Ensure packet fits inside a single netlink attribute */
 678         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 679         if (net_dm_trunc_len)
 680                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 681
 682         msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
 683         if (!msg)
 684                 goto out;
 685
 686         rc = net_dm_packet_report_fill(msg, skb, payload_len);
 687         if (rc) {
 688                 nlmsg_free(msg);
 689                 goto out;
 690         }
 691
 692         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 693
 694 out:
 695         consume_skb(skb);
 696 }
 697
 698 static void net_dm_packet_work(struct work_struct *work)
 699 {
 700         struct per_cpu_dm_data *data;
 701         struct sk_buff_head list;
 702         struct sk_buff *skb;
 703         unsigned long flags;
 704
 705         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 706
 707         __skb_queue_head_init(&list);
 708
 709         spin_lock_irqsave(&data->drop_queue.lock, flags);
 710         skb_queue_splice_tail_init(&data->drop_queue, &list);
 711         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 712
 713         while ((skb = __skb_dequeue(&list)))
 714                 net_dm_packet_report(skb);
 715 }
 716
 717 static size_t
 718 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
 719 {
 720         return hw_metadata->fa_cookie ?
 721                nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
 722 }
 723
 724 static size_t
 725 net_dm_hw_packet_report_size(size_t payload_len,
 726                              const struct devlink_trap_metadata *hw_metadata)
 727 {
 728         size_t size;
 729
 730         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 731
 732         return NLMSG_ALIGN(size) +
 733                /* NET_DM_ATTR_ORIGIN */
 734                nla_total_size(sizeof(u16)) +
 735                /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
 736                nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
 737                /* NET_DM_ATTR_HW_TRAP_NAME */
 738                nla_total_size(strlen(hw_metadata->trap_name) + 1) +
 739                /* NET_DM_ATTR_IN_PORT */
 740                net_dm_in_port_size() +
 741                /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
 742                net_dm_flow_action_cookie_size(hw_metadata) +
 743                /* NET_DM_ATTR_TIMESTAMP */
 744                nla_total_size(sizeof(u64)) +
 745                /* NET_DM_ATTR_ORIG_LEN */
 746                nla_total_size(sizeof(u32)) +
 747                /* NET_DM_ATTR_PROTO */
 748                nla_total_size(sizeof(u16)) +
 749                /* NET_DM_ATTR_PAYLOAD */
 750                nla_total_size(payload_len);
 751 }
 752
 753 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 754                                         struct sk_buff *skb, size_t payload_len)
 755 {
 756         struct devlink_trap_metadata *hw_metadata;
 757         struct nlattr *attr;
 758         void *hdr;
 759
 760         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 761
 762         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 763                           NET_DM_CMD_PACKET_ALERT);
 764         if (!hdr)
 765                 return -EMSGSIZE;
 766
 767         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
 768                 goto nla_put_failure;
 769
 770         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
 771                            hw_metadata->trap_group_name))
 772                 goto nla_put_failure;
 773
 774         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
 775                            hw_metadata->trap_name))
 776                 goto nla_put_failure;
 777
 778         if (hw_metadata->input_dev) {
 779                 struct net_device *dev = hw_metadata->input_dev;
 780                 int rc;
 781
 782                 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
 783                                                       dev->name);
 784                 if (rc)
 785                         goto nla_put_failure;
 786         }
 787
 788         if (hw_metadata->fa_cookie &&
 789             nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
 790                     hw_metadata->fa_cookie->cookie_len,
 791                     hw_metadata->fa_cookie->cookie))
 792                 goto nla_put_failure;
 793
 794         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 795                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 796                 goto nla_put_failure;
 797
 798         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 799                 goto nla_put_failure;
 800
 801         if (!payload_len)
 802                 goto out;
 803
 804         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 805                 goto nla_put_failure;
 806
 807         attr = skb_put(msg, nla_total_size(payload_len));
 808         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 809         attr->nla_len = nla_attr_size(payload_len);
 810         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 811                 goto nla_put_failure;
 812
 813 out:
 814         genlmsg_end(msg, hdr);
 815
 816         return 0;
 817
 818 nla_put_failure:
 819         genlmsg_cancel(msg, hdr);
 820         return -EMSGSIZE;
 821 }
 822
 823 static struct devlink_trap_metadata *
 824 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
 825 {
 826         const struct flow_action_cookie *fa_cookie;
 827         struct devlink_trap_metadata *hw_metadata;
 828         const char *trap_group_name;
 829         const char *trap_name;
 830
 831         hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
 832         if (!hw_metadata)
 833                 return NULL;
 834
 835         trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
 836         if (!trap_group_name)
 837                 goto free_hw_metadata;
 838         hw_metadata->trap_group_name = trap_group_name;
 839
 840         trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
 841         if (!trap_name)
 842                 goto free_trap_group;
 843         hw_metadata->trap_name = trap_name;
 844
 845         if (metadata->fa_cookie) {
 846                 size_t cookie_size = sizeof(*fa_cookie) +
 847                                      metadata->fa_cookie->cookie_len;
 848
 849                 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
 850                                     GFP_ATOMIC);
 851                 if (!fa_cookie)
 852                         goto free_trap_name;
 853                 hw_metadata->fa_cookie = fa_cookie;
 854         }
 855
 856         hw_metadata->input_dev = metadata->input_dev;
 857         dev_hold(hw_metadata->input_dev);
 858
 859         return hw_metadata;
 860
 861 free_trap_name:
 862         kfree(trap_name);
 863 free_trap_group:
 864         kfree(trap_group_name);
 865 free_hw_metadata:
 866         kfree(hw_metadata);
 867         return NULL;
 868 }
 869
 870 static void
 871 net_dm_hw_metadata_free(const struct devlink_trap_metadata *hw_metadata)
 872 {
 873         dev_put(hw_metadata->input_dev);
 874         kfree(hw_metadata->fa_cookie);
 875         kfree(hw_metadata->trap_name);
 876         kfree(hw_metadata->trap_group_name);
 877         kfree(hw_metadata);
 878 }
 879
 880 static void net_dm_hw_packet_report(struct sk_buff *skb)
 881 {
 882         struct devlink_trap_metadata *hw_metadata;
 883         struct sk_buff *msg;
 884         size_t payload_len;
 885         int rc;
 886
 887         if (skb->data > skb_mac_header(skb))
 888                 skb_push(skb, skb->data - skb_mac_header(skb));
 889         else
 890                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 891
 892         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 893         if (net_dm_trunc_len)
 894                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 895
 896         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 897         msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
 898                         GFP_KERNEL);
 899         if (!msg)
 900                 goto out;
 901
 902         rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
 903         if (rc) {
 904                 nlmsg_free(msg);
 905                 goto out;
 906         }
 907
 908         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 909
 910 out:
 911         net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 912         consume_skb(skb);
 913 }
 914
 915 static void net_dm_hw_packet_work(struct work_struct *work)
 916 {
 917         struct per_cpu_dm_data *hw_data;
 918         struct sk_buff_head list;
 919         struct sk_buff *skb;
 920         unsigned long flags;
 921
 922         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 923
 924         __skb_queue_head_init(&list);
 925
 926         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 927         skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
 928         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 929
 930         while ((skb = __skb_dequeue(&list)))
 931                 net_dm_hw_packet_report(skb);
 932 }
 933
 934 static void
 935 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
 936                             struct sk_buff *skb,
 937                             const struct devlink_trap_metadata *metadata)
 938 {
 939         struct devlink_trap_metadata *n_hw_metadata;
 940         ktime_t tstamp = ktime_get_real();
 941         struct per_cpu_dm_data *hw_data;
 942         struct sk_buff *nskb;
 943         unsigned long flags;
 944
 945         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 946                 return;
 947
 948         if (!skb_mac_header_was_set(skb))
 949                 return;
 950
 951         nskb = skb_clone(skb, GFP_ATOMIC);
 952         if (!nskb)
 953                 return;
 954
 955         n_hw_metadata = net_dm_hw_metadata_copy(metadata);
 956         if (!n_hw_metadata)
 957                 goto free;
 958
 959         NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
 960         nskb->tstamp = tstamp;
 961
 962         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 963
 964         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 965         if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
 966                 __skb_queue_tail(&hw_data->drop_queue, nskb);
 967         else
 968                 goto unlock_free;
 969         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 970
 971         schedule_work(&hw_data->dm_alert_work);
 972
 973         return;
 974
 975 unlock_free:
 976         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 977         u64_stats_update_begin(&hw_data->stats.syncp);
 978         hw_data->stats.dropped++;
 979         u64_stats_update_end(&hw_data->stats.syncp);
 980         net_dm_hw_metadata_free(n_hw_metadata);
 981 free:
 982         consume_skb(nskb);
 983 }
 984
 985 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
 986         .kfree_skb_probe        = net_dm_packet_trace_kfree_skb_hit,
 987         .napi_poll_probe        = net_dm_packet_trace_napi_poll_hit,
 988         .work_item_func         = net_dm_packet_work,
 989         .hw_work_item_func      = net_dm_hw_packet_work,
 990         .hw_trap_probe          = net_dm_hw_trap_packet_probe,
 991 };
 992
 993 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
 994         [NET_DM_ALERT_MODE_SUMMARY]     = &net_dm_alert_summary_ops,
 995         [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
 996 };
 997
 998 #if IS_ENABLED(CONFIG_NET_DEVLINK)
 999 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1000 {
1001         return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1002 }
1003
1004 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1005 {
1006         unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1007         tracepoint_synchronize_unregister();
1008 }
1009 #else
1010 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1011 {
1012         return -EOPNOTSUPP;
1013 }
1014
1015 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1016 {
1017 }
1018 #endif
1019
1020 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1021 {
1022         const struct net_dm_alert_ops *ops;
1023         int cpu, rc;
1024
1025         if (monitor_hw) {
1026                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1027                 return -EAGAIN;
1028         }
1029
1030         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1031
1032         if (!try_module_get(THIS_MODULE)) {
1033                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1034                 return -ENODEV;
1035         }
1036
1037         for_each_possible_cpu(cpu) {
1038                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1039                 struct net_dm_hw_entries *hw_entries;
1040
1041                 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1042                 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1043                 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1044                 kfree(hw_entries);
1045         }
1046
1047         rc = net_dm_hw_probe_register(ops);
1048         if (rc) {
1049                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1050                 goto err_module_put;
1051         }
1052
1053         monitor_hw = true;
1054
1055         return 0;
1056
1057 err_module_put:
1058         for_each_possible_cpu(cpu) {
1059                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1060                 struct sk_buff *skb;
1061
1062                 del_timer_sync(&hw_data->send_timer);
1063                 cancel_work_sync(&hw_data->dm_alert_work);
1064                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1065                         struct devlink_trap_metadata *hw_metadata;
1066
1067                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1068                         net_dm_hw_metadata_free(hw_metadata);
1069                         consume_skb(skb);
1070                 }
1071         }
1072         module_put(THIS_MODULE);
1073         return rc;
1074 }
1075
1076 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1077 {
1078         const struct net_dm_alert_ops *ops;
1079         int cpu;
1080
1081         if (!monitor_hw) {
1082                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1083                 return;
1084         }
1085
1086         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1087
1088         monitor_hw = false;
1089
1090         net_dm_hw_probe_unregister(ops);
1091
1092         for_each_possible_cpu(cpu) {
1093                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1094                 struct sk_buff *skb;
1095
1096                 del_timer_sync(&hw_data->send_timer);
1097                 cancel_work_sync(&hw_data->dm_alert_work);
1098                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1099                         struct devlink_trap_metadata *hw_metadata;
1100
1101                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1102                         net_dm_hw_metadata_free(hw_metadata);
1103                         consume_skb(skb);
1104                 }
1105         }
1106
1107         module_put(THIS_MODULE);
1108 }
1109
1110 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1111 {
1112         const struct net_dm_alert_ops *ops;
1113         int cpu, rc;
1114
1115         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1116
1117         if (!try_module_get(THIS_MODULE)) {
1118                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1119                 return -ENODEV;
1120         }
1121
1122         for_each_possible_cpu(cpu) {
1123                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1124                 struct sk_buff *skb;
1125
1126                 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1127                 timer_setup(&data->send_timer, sched_send_work, 0);
1128                 /* Allocate a new per-CPU skb for the summary alert message and
1129                  * free the old one which might contain stale data from
1130                  * previous tracing.
1131                  */
1132                 skb = reset_per_cpu_data(data);
1133                 consume_skb(skb);
1134         }
1135
1136         rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1137         if (rc) {
1138                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1139                 goto err_module_put;
1140         }
1141
1142         rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1143         if (rc) {
1144                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1145                 goto err_unregister_trace;
1146         }
1147
1148         return 0;
1149
1150 err_unregister_trace:
1151         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1152 err_module_put:
1153         for_each_possible_cpu(cpu) {
1154                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1155                 struct sk_buff *skb;
1156
1157                 del_timer_sync(&data->send_timer);
1158                 cancel_work_sync(&data->dm_alert_work);
1159                 while ((skb = __skb_dequeue(&data->drop_queue)))
1160                         consume_skb(skb);
1161         }
1162         module_put(THIS_MODULE);
1163         return rc;
1164 }
1165
1166 static void net_dm_trace_off_set(void)
1167 {
1168         struct dm_hw_stat_delta *new_stat, *temp;
1169         const struct net_dm_alert_ops *ops;
1170         int cpu;
1171
1172         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1173
1174         unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1175         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1176
1177         tracepoint_synchronize_unregister();
1178
1179         /* Make sure we do not send notifications to user space after request
1180          * to stop tracing returns.
1181          */
1182         for_each_possible_cpu(cpu) {
1183                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1184                 struct sk_buff *skb;
1185
1186                 del_timer_sync(&data->send_timer);
1187                 cancel_work_sync(&data->dm_alert_work);
1188                 while ((skb = __skb_dequeue(&data->drop_queue)))
1189                         consume_skb(skb);
1190         }
1191
1192         list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
1193                 if (new_stat->dev == NULL) {
1194                         list_del_rcu(&new_stat->list);
1195                         kfree_rcu(new_stat, rcu);
1196                 }
1197         }
1198
1199         module_put(THIS_MODULE);
1200 }
1201
1202 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1203 {
1204         int rc = 0;
1205
1206         if (state == trace_state) {
1207                 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1208                 return -EAGAIN;
1209         }
1210
1211         switch (state) {
1212         case TRACE_ON:
1213                 rc = net_dm_trace_on_set(extack);
1214                 break;
1215         case TRACE_OFF:
1216                 net_dm_trace_off_set();
1217                 break;
1218         default:
1219                 rc = 1;
1220                 break;
1221         }
1222
1223         if (!rc)
1224                 trace_state = state;
1225         else
1226                 rc = -EINPROGRESS;
1227
1228         return rc;
1229 }
1230
1231 static bool net_dm_is_monitoring(void)
1232 {
1233         return trace_state == TRACE_ON || monitor_hw;
1234 }
1235
1236 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1237                                            enum net_dm_alert_mode *p_alert_mode)
1238 {
1239         u8 val;
1240
1241         val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1242
1243         switch (val) {
1244         case NET_DM_ALERT_MODE_SUMMARY:
1245         case NET_DM_ALERT_MODE_PACKET:
1246                 *p_alert_mode = val;
1247                 break;
1248         default:
1249                 return -EINVAL;
1250         }
1251
1252         return 0;
1253 }
1254
1255 static int net_dm_alert_mode_set(struct genl_info *info)
1256 {
1257         struct netlink_ext_ack *extack = info->extack;
1258         enum net_dm_alert_mode alert_mode;
1259         int rc;
1260
1261         if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1262                 return 0;
1263
1264         rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1265         if (rc) {
1266                 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1267                 return -EINVAL;
1268         }
1269
1270         net_dm_alert_mode = alert_mode;
1271
1272         return 0;
1273 }
1274
1275 static void net_dm_trunc_len_set(struct genl_info *info)
1276 {
1277         if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1278                 return;
1279
1280         net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1281 }
1282
1283 static void net_dm_queue_len_set(struct genl_info *info)
1284 {
1285         if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1286                 return;
1287
1288         net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1289 }
1290
1291 static int net_dm_cmd_config(struct sk_buff *skb,
1292                         struct genl_info *info)
1293 {
1294         struct netlink_ext_ack *extack = info->extack;
1295         int rc;
1296
1297         if (net_dm_is_monitoring()) {
1298                 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1299                 return -EBUSY;
1300         }
1301
1302         rc = net_dm_alert_mode_set(info);
1303         if (rc)
1304                 return rc;
1305
1306         net_dm_trunc_len_set(info);
1307
1308         net_dm_queue_len_set(info);
1309
1310         return 0;
1311 }
1312
1313 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1314                                 struct netlink_ext_ack *extack)
1315 {
1316         bool sw_set = false;
1317         int rc;
1318
1319         if (set_sw) {
1320                 rc = set_all_monitor_traces(TRACE_ON, extack);
1321                 if (rc)
1322                         return rc;
1323                 sw_set = true;
1324         }
1325
1326         if (set_hw) {
1327                 rc = net_dm_hw_monitor_start(extack);
1328                 if (rc)
1329                         goto err_monitor_hw;
1330         }
1331
1332         return 0;
1333
1334 err_monitor_hw:
1335         if (sw_set)
1336                 set_all_monitor_traces(TRACE_OFF, extack);
1337         return rc;
1338 }
1339
1340 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1341                                 struct netlink_ext_ack *extack)
1342 {
1343         if (set_hw)
1344                 net_dm_hw_monitor_stop(extack);
1345         if (set_sw)
1346                 set_all_monitor_traces(TRACE_OFF, extack);
1347 }
1348
1349 static int net_dm_cmd_trace(struct sk_buff *skb,
1350                         struct genl_info *info)
1351 {
1352         bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1353         bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1354         struct netlink_ext_ack *extack = info->extack;
1355
1356         /* To maintain backward compatibility, we start / stop monitoring of
1357          * software drops if no flag is specified.
1358          */
1359         if (!set_sw && !set_hw)
1360                 set_sw = true;
1361
1362         switch (info->genlhdr->cmd) {
1363         case NET_DM_CMD_START:
1364                 return net_dm_monitor_start(set_sw, set_hw, extack);
1365         case NET_DM_CMD_STOP:
1366                 net_dm_monitor_stop(set_sw, set_hw, extack);
1367                 return 0;
1368         }
1369
1370         return -EOPNOTSUPP;
1371 }
1372
1373 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1374 {
1375         void *hdr;
1376
1377         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1378                           &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1379         if (!hdr)
1380                 return -EMSGSIZE;
1381
1382         if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1383                 goto nla_put_failure;
1384
1385         if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1386                 goto nla_put_failure;
1387
1388         if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1389                 goto nla_put_failure;
1390
1391         genlmsg_end(msg, hdr);
1392
1393         return 0;
1394
1395 nla_put_failure:
1396         genlmsg_cancel(msg, hdr);
1397         return -EMSGSIZE;
1398 }
1399
1400 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1401 {
1402         struct sk_buff *msg;
1403         int rc;
1404
1405         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1406         if (!msg)
1407                 return -ENOMEM;
1408
1409         rc = net_dm_config_fill(msg, info);
1410         if (rc)
1411                 goto free_msg;
1412
1413         return genlmsg_reply(msg, info);
1414
1415 free_msg:
1416         nlmsg_free(msg);
1417         return rc;
1418 }
1419
1420 static void net_dm_stats_read(struct net_dm_stats *stats)
1421 {
1422         int cpu;
1423
1424         memset(stats, 0, sizeof(*stats));
1425         for_each_possible_cpu(cpu) {
1426                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1427                 struct net_dm_stats *cpu_stats = &data->stats;
1428                 unsigned int start;
1429                 u64 dropped;
1430
1431                 do {
1432                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1433                         dropped = cpu_stats->dropped;
1434                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1435
1436                 stats->dropped += dropped;
1437         }
1438 }
1439
1440 static int net_dm_stats_put(struct sk_buff *msg)
1441 {
1442         struct net_dm_stats stats;
1443         struct nlattr *attr;
1444
1445         net_dm_stats_read(&stats);
1446
1447         attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1448         if (!attr)
1449                 return -EMSGSIZE;
1450
1451         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1452                               stats.dropped, NET_DM_ATTR_PAD))
1453                 goto nla_put_failure;
1454
1455         nla_nest_end(msg, attr);
1456
1457         return 0;
1458
1459 nla_put_failure:
1460         nla_nest_cancel(msg, attr);
1461         return -EMSGSIZE;
1462 }
1463
1464 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1465 {
1466         int cpu;
1467
1468         memset(stats, 0, sizeof(*stats));
1469         for_each_possible_cpu(cpu) {
1470                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1471                 struct net_dm_stats *cpu_stats = &hw_data->stats;
1472                 unsigned int start;
1473                 u64 dropped;
1474
1475                 do {
1476                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1477                         dropped = cpu_stats->dropped;
1478                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1479
1480                 stats->dropped += dropped;
1481         }
1482 }
1483
1484 static int net_dm_hw_stats_put(struct sk_buff *msg)
1485 {
1486         struct net_dm_stats stats;
1487         struct nlattr *attr;
1488
1489         net_dm_hw_stats_read(&stats);
1490
1491         attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1492         if (!attr)
1493                 return -EMSGSIZE;
1494
1495         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1496                               stats.dropped, NET_DM_ATTR_PAD))
1497                 goto nla_put_failure;
1498
1499         nla_nest_end(msg, attr);
1500
1501         return 0;
1502
1503 nla_put_failure:
1504         nla_nest_cancel(msg, attr);
1505         return -EMSGSIZE;
1506 }
1507
1508 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1509 {
1510         void *hdr;
1511         int rc;
1512
1513         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1514                           &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1515         if (!hdr)
1516                 return -EMSGSIZE;
1517
1518         rc = net_dm_stats_put(msg);
1519         if (rc)
1520                 goto nla_put_failure;
1521
1522         rc = net_dm_hw_stats_put(msg);
1523         if (rc)
1524                 goto nla_put_failure;
1525
1526         genlmsg_end(msg, hdr);
1527
1528         return 0;
1529
1530 nla_put_failure:
1531         genlmsg_cancel(msg, hdr);
1532         return -EMSGSIZE;
1533 }
1534
1535 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1536 {
1537         struct sk_buff *msg;
1538         int rc;
1539
1540         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1541         if (!msg)
1542                 return -ENOMEM;
1543
1544         rc = net_dm_stats_fill(msg, info);
1545         if (rc)
1546                 goto free_msg;
1547
1548         return genlmsg_reply(msg, info);
1549
1550 free_msg:
1551         nlmsg_free(msg);
1552         return rc;
1553 }
1554
1555 static int dropmon_net_event(struct notifier_block *ev_block,
1556                              unsigned long event, void *ptr)
1557 {
1558         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1559         struct dm_hw_stat_delta *new_stat = NULL;
1560         struct dm_hw_stat_delta *tmp;
1561
1562         switch (event) {
1563         case NETDEV_REGISTER:
1564                 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
1565
1566                 if (!new_stat)
1567                         goto out;
1568
1569                 new_stat->dev = dev;
1570                 new_stat->last_rx = jiffies;
1571                 mutex_lock(&net_dm_mutex);
1572                 list_add_rcu(&new_stat->list, &hw_stats_list);
1573                 mutex_unlock(&net_dm_mutex);
1574                 break;
1575         case NETDEV_UNREGISTER:
1576                 mutex_lock(&net_dm_mutex);
1577                 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
1578                         if (new_stat->dev == dev) {
1579
1580                                 /* Paired with READ_ONCE() in trace_napi_poll_hit() */
1581                                 WRITE_ONCE(new_stat->dev, NULL);
1582
1583                                 if (trace_state == TRACE_OFF) {
1584                                         list_del_rcu(&new_stat->list);
1585                                         kfree_rcu(new_stat, rcu);
1586                                         break;
1587                                 }
1588                         }
1589                 }
1590                 mutex_unlock(&net_dm_mutex);
1591                 break;
1592         }
1593 out:
1594         return NOTIFY_DONE;
1595 }
1596
1597 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1598         [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1599         [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1600         [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1601         [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1602         [NET_DM_ATTR_SW_DROPS]  = {. type = NLA_FLAG },
1603         [NET_DM_ATTR_HW_DROPS]  = {. type = NLA_FLAG },
1604 };
1605
1606 static const struct genl_small_ops dropmon_ops[] = {
1607         {
1608                 .cmd = NET_DM_CMD_CONFIG,
1609                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1610                 .doit = net_dm_cmd_config,
1611                 .flags = GENL_ADMIN_PERM,
1612         },
1613         {
1614                 .cmd = NET_DM_CMD_START,
1615                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1616                 .doit = net_dm_cmd_trace,
1617         },
1618         {
1619                 .cmd = NET_DM_CMD_STOP,
1620                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1621                 .doit = net_dm_cmd_trace,
1622         },
1623         {
1624                 .cmd = NET_DM_CMD_CONFIG_GET,
1625                 .doit = net_dm_cmd_config_get,
1626         },
1627         {
1628                 .cmd = NET_DM_CMD_STATS_GET,
1629                 .doit = net_dm_cmd_stats_get,
1630         },
1631 };
1632
1633 static int net_dm_nl_pre_doit(const struct genl_ops *ops,
1634                               struct sk_buff *skb, struct genl_info *info)
1635 {
1636         mutex_lock(&net_dm_mutex);
1637
1638         return 0;
1639 }
1640
1641 static void net_dm_nl_post_doit(const struct genl_ops *ops,
1642                                 struct sk_buff *skb, struct genl_info *info)
1643 {
1644         mutex_unlock(&net_dm_mutex);
1645 }
1646
1647 static struct genl_family net_drop_monitor_family __ro_after_init = {
1648         .hdrsize        = 0,
1649         .name           = "NET_DM",
1650         .version        = 2,
1651         .maxattr        = NET_DM_ATTR_MAX,
1652         .policy         = net_dm_nl_policy,
1653         .pre_doit       = net_dm_nl_pre_doit,
1654         .post_doit      = net_dm_nl_post_doit,
1655         .module         = THIS_MODULE,
1656         .small_ops      = dropmon_ops,
1657         .n_small_ops    = ARRAY_SIZE(dropmon_ops),
1658         .mcgrps         = dropmon_mcgrps,
1659         .n_mcgrps       = ARRAY_SIZE(dropmon_mcgrps),
1660 };
1661
1662 static struct notifier_block dropmon_net_notifier = {
1663         .notifier_call = dropmon_net_event
1664 };
1665
1666 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1667 {
1668         spin_lock_init(&data->lock);
1669         skb_queue_head_init(&data->drop_queue);
1670         u64_stats_init(&data->stats.syncp);
1671 }
1672
1673 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1674 {
1675         WARN_ON(!skb_queue_empty(&data->drop_queue));
1676 }
1677
1678 static void net_dm_cpu_data_init(int cpu)
1679 {
1680         struct per_cpu_dm_data *data;
1681
1682         data = &per_cpu(dm_cpu_data, cpu);
1683         __net_dm_cpu_data_init(data);
1684 }
1685
1686 static void net_dm_cpu_data_fini(int cpu)
1687 {
1688         struct per_cpu_dm_data *data;
1689
1690         data = &per_cpu(dm_cpu_data, cpu);
1691         /* At this point, we should have exclusive access
1692          * to this struct and can free the skb inside it.
1693          */
1694         consume_skb(data->skb);
1695         __net_dm_cpu_data_fini(data);
1696 }
1697
1698 static void net_dm_hw_cpu_data_init(int cpu)
1699 {
1700         struct per_cpu_dm_data *hw_data;
1701
1702         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1703         __net_dm_cpu_data_init(hw_data);
1704 }
1705
1706 static void net_dm_hw_cpu_data_fini(int cpu)
1707 {
1708         struct per_cpu_dm_data *hw_data;
1709
1710         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1711         kfree(hw_data->hw_entries);
1712         __net_dm_cpu_data_fini(hw_data);
1713 }
1714
1715 static int __init init_net_drop_monitor(void)
1716 {
1717         int cpu, rc;
1718
1719         pr_info("Initializing network drop monitor service\n");
1720
1721         if (sizeof(void *) > 8) {
1722                 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1723                 return -ENOSPC;
1724         }
1725
1726         rc = genl_register_family(&net_drop_monitor_family);
1727         if (rc) {
1728                 pr_err("Could not create drop monitor netlink family\n");
1729                 return rc;
1730         }
1731         WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1732
1733         rc = register_netdevice_notifier(&dropmon_net_notifier);
1734         if (rc < 0) {
1735                 pr_crit("Failed to register netdevice notifier\n");
1736                 goto out_unreg;
1737         }
1738
1739         rc = 0;
1740
1741         for_each_possible_cpu(cpu) {
1742                 net_dm_cpu_data_init(cpu);
1743                 net_dm_hw_cpu_data_init(cpu);
1744         }
1745
1746         goto out;
1747
1748 out_unreg:
1749         genl_unregister_family(&net_drop_monitor_family);
1750 out:
1751         return rc;
1752 }
1753
1754 static void exit_net_drop_monitor(void)
1755 {
1756         int cpu;
1757
1758         BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1759
1760         /*
1761          * Because of the module_get/put we do in the trace state change path
1762          * we are guaranteed not to have any current users when we get here
1763          */
1764
1765         for_each_possible_cpu(cpu) {
1766                 net_dm_hw_cpu_data_fini(cpu);
1767                 net_dm_cpu_data_fini(cpu);
1768         }
1769
1770         BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1771 }
1772
1773 module_init(init_net_drop_monitor);
1774 module_exit(exit_net_drop_monitor);
1775
1776 MODULE_LICENSE("GPL v2");
1777 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1778 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1779 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");