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 <[email protected]>
   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/bitfield.h>
  25 #include <linux/percpu.h>
  26 #include <linux/timer.h>
  27 #include <linux/bitops.h>
  28 #include <linux/slab.h>
  29 #include <linux/module.h>
  30 #include <net/genetlink.h>
  31 #include <net/netevent.h>
  32 #include <net/flow_offload.h>
  33 #include <net/dropreason.h>
  34 #include <net/devlink.h>
  35
  36 #include <trace/events/skb.h>
  37 #include <trace/events/napi.h>
  38 #include <trace/events/devlink.h>
  39
  40 #include <asm/unaligned.h>
  41
  42 #define TRACE_ON 1
  43 #define TRACE_OFF 0
  44
  45 /*
  46  * Globals, our netlink socket pointer
  47  * and the work handle that will send up
  48  * netlink alerts
  49  */
  50 static int trace_state = TRACE_OFF;
  51 static bool monitor_hw;
  52
  53 /* net_dm_mutex
  54  *
  55  * An overall lock guarding every operation coming from userspace.
  56  */
  57 static DEFINE_MUTEX(net_dm_mutex);
  58
  59 struct net_dm_stats {
  60         u64_stats_t dropped;
  61         struct u64_stats_sync syncp;
  62 };
  63
  64 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
  65
  66 struct net_dm_hw_entry {
  67         char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  68         u32 count;
  69 };
  70
  71 struct net_dm_hw_entries {
  72         u32 num_entries;
  73         struct net_dm_hw_entry entries[];
  74 };
  75
  76 struct per_cpu_dm_data {
  77         spinlock_t              lock;   /* Protects 'skb', 'hw_entries' and
  78                                          * 'send_timer'
  79                                          */
  80         union {
  81                 struct sk_buff                  *skb;
  82                 struct net_dm_hw_entries        *hw_entries;
  83         };
  84         struct sk_buff_head     drop_queue;
  85         struct work_struct      dm_alert_work;
  86         struct timer_list       send_timer;
  87         struct net_dm_stats     stats;
  88 };
  89
  90 struct dm_hw_stat_delta {
  91         unsigned long last_rx;
  92         unsigned long last_drop_val;
  93         struct rcu_head rcu;
  94 };
  95
  96 static struct genl_family net_drop_monitor_family;
  97
  98 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
  99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 100
 101 static int dm_hit_limit = 64;
 102 static int dm_delay = 1;
 103 static unsigned long dm_hw_check_delta = 2*HZ;
 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                                 enum skb_drop_reason reason);
 113         void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 114                                 int work, int budget);
 115         void (*work_item_func)(struct work_struct *work);
 116         void (*hw_work_item_func)(struct work_struct *work);
 117         void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
 118                               struct sk_buff *skb,
 119                               const struct devlink_trap_metadata *metadata);
 120 };
 121
 122 struct net_dm_skb_cb {
 123         union {
 124                 struct devlink_trap_metadata *hw_metadata;
 125                 void *pc;
 126         };
 127         enum skb_drop_reason reason;
 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,
 266                                 void *location,
 267                                 enum skb_drop_reason reason)
 268 {
 269         trace_drop_common(skb, location);
 270 }
 271
 272 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 273                                 int work, int budget)
 274 {
 275         struct net_device *dev = napi->dev;
 276         struct dm_hw_stat_delta *stat;
 277         /*
 278          * Don't check napi structures with no associated device
 279          */
 280         if (!dev)
 281                 return;
 282
 283         rcu_read_lock();
 284         stat = rcu_dereference(dev->dm_private);
 285         if (stat) {
 286                 /*
 287                  * only add a note to our monitor buffer if:
 288                  * 1) its after the last_rx delta
 289                  * 2) our rx_dropped count has gone up
 290                  */
 291                 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) &&
 292                     (dev->stats.rx_dropped != stat->last_drop_val)) {
 293                         trace_drop_common(NULL, NULL);
 294                         stat->last_drop_val = dev->stats.rx_dropped;
 295                         stat->last_rx = jiffies;
 296                 }
 297         }
 298         rcu_read_unlock();
 299 }
 300
 301 static struct net_dm_hw_entries *
 302 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 303 {
 304         struct net_dm_hw_entries *hw_entries;
 305         unsigned long flags;
 306
 307         hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
 308                              GFP_KERNEL);
 309         if (!hw_entries) {
 310                 /* If the memory allocation failed, we try to perform another
 311                  * allocation in 1/10 second. Otherwise, the probe function
 312                  * will constantly bail out.
 313                  */
 314                 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 315         }
 316
 317         spin_lock_irqsave(&hw_data->lock, flags);
 318         swap(hw_data->hw_entries, hw_entries);
 319         spin_unlock_irqrestore(&hw_data->lock, flags);
 320
 321         return hw_entries;
 322 }
 323
 324 static int net_dm_hw_entry_put(struct sk_buff *msg,
 325                                const struct net_dm_hw_entry *hw_entry)
 326 {
 327         struct nlattr *attr;
 328
 329         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
 330         if (!attr)
 331                 return -EMSGSIZE;
 332
 333         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
 334                 goto nla_put_failure;
 335
 336         if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
 337                 goto nla_put_failure;
 338
 339         nla_nest_end(msg, attr);
 340
 341         return 0;
 342
 343 nla_put_failure:
 344         nla_nest_cancel(msg, attr);
 345         return -EMSGSIZE;
 346 }
 347
 348 static int net_dm_hw_entries_put(struct sk_buff *msg,
 349                                  const struct net_dm_hw_entries *hw_entries)
 350 {
 351         struct nlattr *attr;
 352         int i;
 353
 354         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
 355         if (!attr)
 356                 return -EMSGSIZE;
 357
 358         for (i = 0; i < hw_entries->num_entries; i++) {
 359                 int rc;
 360
 361                 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
 362                 if (rc)
 363                         goto nla_put_failure;
 364         }
 365
 366         nla_nest_end(msg, attr);
 367
 368         return 0;
 369
 370 nla_put_failure:
 371         nla_nest_cancel(msg, attr);
 372         return -EMSGSIZE;
 373 }
 374
 375 static int
 376 net_dm_hw_summary_report_fill(struct sk_buff *msg,
 377                               const struct net_dm_hw_entries *hw_entries)
 378 {
 379         struct net_dm_alert_msg anc_hdr = { 0 };
 380         void *hdr;
 381         int rc;
 382
 383         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 384                           NET_DM_CMD_ALERT);
 385         if (!hdr)
 386                 return -EMSGSIZE;
 387
 388         /* We need to put the ancillary header in order not to break user
 389          * space.
 390          */
 391         if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
 392                 goto nla_put_failure;
 393
 394         rc = net_dm_hw_entries_put(msg, hw_entries);
 395         if (rc)
 396                 goto nla_put_failure;
 397
 398         genlmsg_end(msg, hdr);
 399
 400         return 0;
 401
 402 nla_put_failure:
 403         genlmsg_cancel(msg, hdr);
 404         return -EMSGSIZE;
 405 }
 406
 407 static void net_dm_hw_summary_work(struct work_struct *work)
 408 {
 409         struct net_dm_hw_entries *hw_entries;
 410         struct per_cpu_dm_data *hw_data;
 411         struct sk_buff *msg;
 412         int rc;
 413
 414         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 415
 416         hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
 417         if (!hw_entries)
 418                 return;
 419
 420         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 421         if (!msg)
 422                 goto out;
 423
 424         rc = net_dm_hw_summary_report_fill(msg, hw_entries);
 425         if (rc) {
 426                 nlmsg_free(msg);
 427                 goto out;
 428         }
 429
 430         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 431
 432 out:
 433         kfree(hw_entries);
 434 }
 435
 436 static void
 437 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
 438                              struct sk_buff *skb,
 439                              const struct devlink_trap_metadata *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         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 448                 return;
 449
 450         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 451         spin_lock_irqsave(&hw_data->lock, flags);
 452         hw_entries = hw_data->hw_entries;
 453
 454         if (!hw_entries)
 455                 goto out;
 456
 457         for (i = 0; i < hw_entries->num_entries; i++) {
 458                 hw_entry = &hw_entries->entries[i];
 459                 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
 460                              NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
 461                         hw_entry->count++;
 462                         goto out;
 463                 }
 464         }
 465         if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
 466                 goto out;
 467
 468         hw_entry = &hw_entries->entries[hw_entries->num_entries];
 469         strscpy(hw_entry->trap_name, metadata->trap_name,
 470                 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
 471         hw_entry->count = 1;
 472         hw_entries->num_entries++;
 473
 474         if (!timer_pending(&hw_data->send_timer)) {
 475                 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
 476                 add_timer(&hw_data->send_timer);
 477         }
 478
 479 out:
 480         spin_unlock_irqrestore(&hw_data->lock, flags);
 481 }
 482
 483 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 484         .kfree_skb_probe        = trace_kfree_skb_hit,
 485         .napi_poll_probe        = trace_napi_poll_hit,
 486         .work_item_func         = send_dm_alert,
 487         .hw_work_item_func      = net_dm_hw_summary_work,
 488         .hw_trap_probe          = net_dm_hw_trap_summary_probe,
 489 };
 490
 491 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 492                                               struct sk_buff *skb,
 493                                               void *location,
 494                                               enum skb_drop_reason reason)
 495 {
 496         ktime_t tstamp = ktime_get_real();
 497         struct per_cpu_dm_data *data;
 498         struct net_dm_skb_cb *cb;
 499         struct sk_buff *nskb;
 500         unsigned long flags;
 501
 502         if (!skb_mac_header_was_set(skb))
 503                 return;
 504
 505         nskb = skb_clone(skb, GFP_ATOMIC);
 506         if (!nskb)
 507                 return;
 508
 509         cb = NET_DM_SKB_CB(nskb);
 510         cb->reason = reason;
 511         cb->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         u64_stats_inc(&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 #define NET_DM_MAX_REASON_LEN 50
 556
 557 static size_t net_dm_packet_report_size(size_t payload_len)
 558 {
 559         size_t size;
 560
 561         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 562
 563         return NLMSG_ALIGN(size) +
 564                /* NET_DM_ATTR_ORIGIN */
 565                nla_total_size(sizeof(u16)) +
 566                /* NET_DM_ATTR_PC */
 567                nla_total_size(sizeof(u64)) +
 568                /* NET_DM_ATTR_SYMBOL */
 569                nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
 570                /* NET_DM_ATTR_IN_PORT */
 571                net_dm_in_port_size() +
 572                /* NET_DM_ATTR_TIMESTAMP */
 573                nla_total_size(sizeof(u64)) +
 574                /* NET_DM_ATTR_ORIG_LEN */
 575                nla_total_size(sizeof(u32)) +
 576                /* NET_DM_ATTR_PROTO */
 577                nla_total_size(sizeof(u16)) +
 578                /* NET_DM_ATTR_REASON */
 579                nla_total_size(NET_DM_MAX_REASON_LEN + 1) +
 580                /* NET_DM_ATTR_PAYLOAD */
 581                nla_total_size(payload_len);
 582 }
 583
 584 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
 585                                             const char *name)
 586 {
 587         struct nlattr *attr;
 588
 589         attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
 590         if (!attr)
 591                 return -EMSGSIZE;
 592
 593         if (ifindex &&
 594             nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
 595                 goto nla_put_failure;
 596
 597         if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
 598                 goto nla_put_failure;
 599
 600         nla_nest_end(msg, attr);
 601
 602         return 0;
 603
 604 nla_put_failure:
 605         nla_nest_cancel(msg, attr);
 606         return -EMSGSIZE;
 607 }
 608
 609 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
 610                                      size_t payload_len)
 611 {
 612         struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
 613         const struct drop_reason_list *list = NULL;
 614         unsigned int subsys, subsys_reason;
 615         char buf[NET_DM_MAX_SYMBOL_LEN];
 616         struct nlattr *attr;
 617         void *hdr;
 618         int rc;
 619
 620         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 621                           NET_DM_CMD_PACKET_ALERT);
 622         if (!hdr)
 623                 return -EMSGSIZE;
 624
 625         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
 626                 goto nla_put_failure;
 627
 628         if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc,
 629                               NET_DM_ATTR_PAD))
 630                 goto nla_put_failure;
 631
 632         rcu_read_lock();
 633         subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK);
 634         if (subsys < SKB_DROP_REASON_SUBSYS_NUM)
 635                 list = rcu_dereference(drop_reasons_by_subsys[subsys]);
 636         subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK;
 637         if (!list ||
 638             subsys_reason >= list->n_reasons ||
 639             !list->reasons[subsys_reason] ||
 640             strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) {
 641                 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]);
 642                 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 643         }
 644         if (nla_put_string(msg, NET_DM_ATTR_REASON,
 645                            list->reasons[subsys_reason])) {
 646                 rcu_read_unlock();
 647                 goto nla_put_failure;
 648         }
 649         rcu_read_unlock();
 650
 651         snprintf(buf, sizeof(buf), "%pS", cb->pc);
 652         if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
 653                 goto nla_put_failure;
 654
 655         rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
 656         if (rc)
 657                 goto nla_put_failure;
 658
 659         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 660                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 661                 goto nla_put_failure;
 662
 663         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 664                 goto nla_put_failure;
 665
 666         if (!payload_len)
 667                 goto out;
 668
 669         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 670                 goto nla_put_failure;
 671
 672         attr = skb_put(msg, nla_total_size(payload_len));
 673         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 674         attr->nla_len = nla_attr_size(payload_len);
 675         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 676                 goto nla_put_failure;
 677
 678 out:
 679         genlmsg_end(msg, hdr);
 680
 681         return 0;
 682
 683 nla_put_failure:
 684         genlmsg_cancel(msg, hdr);
 685         return -EMSGSIZE;
 686 }
 687
 688 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
 689
 690 static void net_dm_packet_report(struct sk_buff *skb)
 691 {
 692         struct sk_buff *msg;
 693         size_t payload_len;
 694         int rc;
 695
 696         /* Make sure we start copying the packet from the MAC header */
 697         if (skb->data > skb_mac_header(skb))
 698                 skb_push(skb, skb->data - skb_mac_header(skb));
 699         else
 700                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 701
 702         /* Ensure packet fits inside a single netlink attribute */
 703         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 704         if (net_dm_trunc_len)
 705                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 706
 707         msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
 708         if (!msg)
 709                 goto out;
 710
 711         rc = net_dm_packet_report_fill(msg, skb, payload_len);
 712         if (rc) {
 713                 nlmsg_free(msg);
 714                 goto out;
 715         }
 716
 717         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 718
 719 out:
 720         consume_skb(skb);
 721 }
 722
 723 static void net_dm_packet_work(struct work_struct *work)
 724 {
 725         struct per_cpu_dm_data *data;
 726         struct sk_buff_head list;
 727         struct sk_buff *skb;
 728         unsigned long flags;
 729
 730         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 731
 732         __skb_queue_head_init(&list);
 733
 734         spin_lock_irqsave(&data->drop_queue.lock, flags);
 735         skb_queue_splice_tail_init(&data->drop_queue, &list);
 736         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 737
 738         while ((skb = __skb_dequeue(&list)))
 739                 net_dm_packet_report(skb);
 740 }
 741
 742 static size_t
 743 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
 744 {
 745         return hw_metadata->fa_cookie ?
 746                nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
 747 }
 748
 749 static size_t
 750 net_dm_hw_packet_report_size(size_t payload_len,
 751                              const struct devlink_trap_metadata *hw_metadata)
 752 {
 753         size_t size;
 754
 755         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 756
 757         return NLMSG_ALIGN(size) +
 758                /* NET_DM_ATTR_ORIGIN */
 759                nla_total_size(sizeof(u16)) +
 760                /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
 761                nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
 762                /* NET_DM_ATTR_HW_TRAP_NAME */
 763                nla_total_size(strlen(hw_metadata->trap_name) + 1) +
 764                /* NET_DM_ATTR_IN_PORT */
 765                net_dm_in_port_size() +
 766                /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
 767                net_dm_flow_action_cookie_size(hw_metadata) +
 768                /* NET_DM_ATTR_TIMESTAMP */
 769                nla_total_size(sizeof(u64)) +
 770                /* NET_DM_ATTR_ORIG_LEN */
 771                nla_total_size(sizeof(u32)) +
 772                /* NET_DM_ATTR_PROTO */
 773                nla_total_size(sizeof(u16)) +
 774                /* NET_DM_ATTR_PAYLOAD */
 775                nla_total_size(payload_len);
 776 }
 777
 778 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 779                                         struct sk_buff *skb, size_t payload_len)
 780 {
 781         struct devlink_trap_metadata *hw_metadata;
 782         struct nlattr *attr;
 783         void *hdr;
 784
 785         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 786
 787         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 788                           NET_DM_CMD_PACKET_ALERT);
 789         if (!hdr)
 790                 return -EMSGSIZE;
 791
 792         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
 793                 goto nla_put_failure;
 794
 795         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
 796                            hw_metadata->trap_group_name))
 797                 goto nla_put_failure;
 798
 799         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
 800                            hw_metadata->trap_name))
 801                 goto nla_put_failure;
 802
 803         if (hw_metadata->input_dev) {
 804                 struct net_device *dev = hw_metadata->input_dev;
 805                 int rc;
 806
 807                 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
 808                                                       dev->name);
 809                 if (rc)
 810                         goto nla_put_failure;
 811         }
 812
 813         if (hw_metadata->fa_cookie &&
 814             nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
 815                     hw_metadata->fa_cookie->cookie_len,
 816                     hw_metadata->fa_cookie->cookie))
 817                 goto nla_put_failure;
 818
 819         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 820                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 821                 goto nla_put_failure;
 822
 823         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 824                 goto nla_put_failure;
 825
 826         if (!payload_len)
 827                 goto out;
 828
 829         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 830                 goto nla_put_failure;
 831
 832         attr = skb_put(msg, nla_total_size(payload_len));
 833         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 834         attr->nla_len = nla_attr_size(payload_len);
 835         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 836                 goto nla_put_failure;
 837
 838 out:
 839         genlmsg_end(msg, hdr);
 840
 841         return 0;
 842
 843 nla_put_failure:
 844         genlmsg_cancel(msg, hdr);
 845         return -EMSGSIZE;
 846 }
 847
 848 static struct devlink_trap_metadata *
 849 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
 850 {
 851         const struct flow_action_cookie *fa_cookie;
 852         struct devlink_trap_metadata *hw_metadata;
 853         const char *trap_group_name;
 854         const char *trap_name;
 855
 856         hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
 857         if (!hw_metadata)
 858                 return NULL;
 859
 860         trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
 861         if (!trap_group_name)
 862                 goto free_hw_metadata;
 863         hw_metadata->trap_group_name = trap_group_name;
 864
 865         trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
 866         if (!trap_name)
 867                 goto free_trap_group;
 868         hw_metadata->trap_name = trap_name;
 869
 870         if (metadata->fa_cookie) {
 871                 size_t cookie_size = sizeof(*fa_cookie) +
 872                                      metadata->fa_cookie->cookie_len;
 873
 874                 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
 875                                     GFP_ATOMIC);
 876                 if (!fa_cookie)
 877                         goto free_trap_name;
 878                 hw_metadata->fa_cookie = fa_cookie;
 879         }
 880
 881         hw_metadata->input_dev = metadata->input_dev;
 882         netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker,
 883                     GFP_ATOMIC);
 884
 885         return hw_metadata;
 886
 887 free_trap_name:
 888         kfree(trap_name);
 889 free_trap_group:
 890         kfree(trap_group_name);
 891 free_hw_metadata:
 892         kfree(hw_metadata);
 893         return NULL;
 894 }
 895
 896 static void
 897 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
 898 {
 899         netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker);
 900         kfree(hw_metadata->fa_cookie);
 901         kfree(hw_metadata->trap_name);
 902         kfree(hw_metadata->trap_group_name);
 903         kfree(hw_metadata);
 904 }
 905
 906 static void net_dm_hw_packet_report(struct sk_buff *skb)
 907 {
 908         struct devlink_trap_metadata *hw_metadata;
 909         struct sk_buff *msg;
 910         size_t payload_len;
 911         int rc;
 912
 913         if (skb->data > skb_mac_header(skb))
 914                 skb_push(skb, skb->data - skb_mac_header(skb));
 915         else
 916                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 917
 918         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 919         if (net_dm_trunc_len)
 920                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 921
 922         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 923         msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
 924                         GFP_KERNEL);
 925         if (!msg)
 926                 goto out;
 927
 928         rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
 929         if (rc) {
 930                 nlmsg_free(msg);
 931                 goto out;
 932         }
 933
 934         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 935
 936 out:
 937         net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 938         consume_skb(skb);
 939 }
 940
 941 static void net_dm_hw_packet_work(struct work_struct *work)
 942 {
 943         struct per_cpu_dm_data *hw_data;
 944         struct sk_buff_head list;
 945         struct sk_buff *skb;
 946         unsigned long flags;
 947
 948         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 949
 950         __skb_queue_head_init(&list);
 951
 952         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 953         skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
 954         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 955
 956         while ((skb = __skb_dequeue(&list)))
 957                 net_dm_hw_packet_report(skb);
 958 }
 959
 960 static void
 961 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
 962                             struct sk_buff *skb,
 963                             const struct devlink_trap_metadata *metadata)
 964 {
 965         struct devlink_trap_metadata *n_hw_metadata;
 966         ktime_t tstamp = ktime_get_real();
 967         struct per_cpu_dm_data *hw_data;
 968         struct sk_buff *nskb;
 969         unsigned long flags;
 970
 971         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 972                 return;
 973
 974         if (!skb_mac_header_was_set(skb))
 975                 return;
 976
 977         nskb = skb_clone(skb, GFP_ATOMIC);
 978         if (!nskb)
 979                 return;
 980
 981         n_hw_metadata = net_dm_hw_metadata_copy(metadata);
 982         if (!n_hw_metadata)
 983                 goto free;
 984
 985         NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
 986         nskb->tstamp = tstamp;
 987
 988         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 989
 990         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 991         if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
 992                 __skb_queue_tail(&hw_data->drop_queue, nskb);
 993         else
 994                 goto unlock_free;
 995         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 996
 997         schedule_work(&hw_data->dm_alert_work);
 998
 999         return;
1000
1001 unlock_free:
1002         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
1003         u64_stats_update_begin(&hw_data->stats.syncp);
1004         u64_stats_inc(&hw_data->stats.dropped);
1005         u64_stats_update_end(&hw_data->stats.syncp);
1006         net_dm_hw_metadata_free(n_hw_metadata);
1007 free:
1008         consume_skb(nskb);
1009 }
1010
1011 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
1012         .kfree_skb_probe        = net_dm_packet_trace_kfree_skb_hit,
1013         .napi_poll_probe        = net_dm_packet_trace_napi_poll_hit,
1014         .work_item_func         = net_dm_packet_work,
1015         .hw_work_item_func      = net_dm_hw_packet_work,
1016         .hw_trap_probe          = net_dm_hw_trap_packet_probe,
1017 };
1018
1019 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1020         [NET_DM_ALERT_MODE_SUMMARY]     = &net_dm_alert_summary_ops,
1021         [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
1022 };
1023
1024 #if IS_ENABLED(CONFIG_NET_DEVLINK)
1025 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1026 {
1027         return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1028 }
1029
1030 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1031 {
1032         unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1033         tracepoint_synchronize_unregister();
1034 }
1035 #else
1036 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1037 {
1038         return -EOPNOTSUPP;
1039 }
1040
1041 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1042 {
1043 }
1044 #endif
1045
1046 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1047 {
1048         const struct net_dm_alert_ops *ops;
1049         int cpu, rc;
1050
1051         if (monitor_hw) {
1052                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1053                 return -EAGAIN;
1054         }
1055
1056         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1057
1058         if (!try_module_get(THIS_MODULE)) {
1059                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1060                 return -ENODEV;
1061         }
1062
1063         for_each_possible_cpu(cpu) {
1064                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1065                 struct net_dm_hw_entries *hw_entries;
1066
1067                 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1068                 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1069                 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1070                 kfree(hw_entries);
1071         }
1072
1073         rc = net_dm_hw_probe_register(ops);
1074         if (rc) {
1075                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1076                 goto err_module_put;
1077         }
1078
1079         monitor_hw = true;
1080
1081         return 0;
1082
1083 err_module_put:
1084         for_each_possible_cpu(cpu) {
1085                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1086                 struct sk_buff *skb;
1087
1088                 del_timer_sync(&hw_data->send_timer);
1089                 cancel_work_sync(&hw_data->dm_alert_work);
1090                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1091                         struct devlink_trap_metadata *hw_metadata;
1092
1093                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1094                         net_dm_hw_metadata_free(hw_metadata);
1095                         consume_skb(skb);
1096                 }
1097         }
1098         module_put(THIS_MODULE);
1099         return rc;
1100 }
1101
1102 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1103 {
1104         const struct net_dm_alert_ops *ops;
1105         int cpu;
1106
1107         if (!monitor_hw) {
1108                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1109                 return;
1110         }
1111
1112         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1113
1114         monitor_hw = false;
1115
1116         net_dm_hw_probe_unregister(ops);
1117
1118         for_each_possible_cpu(cpu) {
1119                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1120                 struct sk_buff *skb;
1121
1122                 del_timer_sync(&hw_data->send_timer);
1123                 cancel_work_sync(&hw_data->dm_alert_work);
1124                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1125                         struct devlink_trap_metadata *hw_metadata;
1126
1127                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1128                         net_dm_hw_metadata_free(hw_metadata);
1129                         consume_skb(skb);
1130                 }
1131         }
1132
1133         module_put(THIS_MODULE);
1134 }
1135
1136 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1137 {
1138         const struct net_dm_alert_ops *ops;
1139         int cpu, rc;
1140
1141         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1142
1143         if (!try_module_get(THIS_MODULE)) {
1144                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1145                 return -ENODEV;
1146         }
1147
1148         for_each_possible_cpu(cpu) {
1149                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1150                 struct sk_buff *skb;
1151
1152                 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1153                 timer_setup(&data->send_timer, sched_send_work, 0);
1154                 /* Allocate a new per-CPU skb for the summary alert message and
1155                  * free the old one which might contain stale data from
1156                  * previous tracing.
1157                  */
1158                 skb = reset_per_cpu_data(data);
1159                 consume_skb(skb);
1160         }
1161
1162         rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1163         if (rc) {
1164                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1165                 goto err_module_put;
1166         }
1167
1168         rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1169         if (rc) {
1170                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1171                 goto err_unregister_trace;
1172         }
1173
1174         return 0;
1175
1176 err_unregister_trace:
1177         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1178 err_module_put:
1179         for_each_possible_cpu(cpu) {
1180                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1181                 struct sk_buff *skb;
1182
1183                 del_timer_sync(&data->send_timer);
1184                 cancel_work_sync(&data->dm_alert_work);
1185                 while ((skb = __skb_dequeue(&data->drop_queue)))
1186                         consume_skb(skb);
1187         }
1188         module_put(THIS_MODULE);
1189         return rc;
1190 }
1191
1192 static void net_dm_trace_off_set(void)
1193 {
1194         const struct net_dm_alert_ops *ops;
1195         int cpu;
1196
1197         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1198
1199         unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1200         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1201
1202         tracepoint_synchronize_unregister();
1203
1204         /* Make sure we do not send notifications to user space after request
1205          * to stop tracing returns.
1206          */
1207         for_each_possible_cpu(cpu) {
1208                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1209                 struct sk_buff *skb;
1210
1211                 del_timer_sync(&data->send_timer);
1212                 cancel_work_sync(&data->dm_alert_work);
1213                 while ((skb = __skb_dequeue(&data->drop_queue)))
1214                         consume_skb(skb);
1215         }
1216
1217         module_put(THIS_MODULE);
1218 }
1219
1220 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1221 {
1222         int rc = 0;
1223
1224         if (state == trace_state) {
1225                 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1226                 return -EAGAIN;
1227         }
1228
1229         switch (state) {
1230         case TRACE_ON:
1231                 rc = net_dm_trace_on_set(extack);
1232                 break;
1233         case TRACE_OFF:
1234                 net_dm_trace_off_set();
1235                 break;
1236         default:
1237                 rc = 1;
1238                 break;
1239         }
1240
1241         if (!rc)
1242                 trace_state = state;
1243         else
1244                 rc = -EINPROGRESS;
1245
1246         return rc;
1247 }
1248
1249 static bool net_dm_is_monitoring(void)
1250 {
1251         return trace_state == TRACE_ON || monitor_hw;
1252 }
1253
1254 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1255                                            enum net_dm_alert_mode *p_alert_mode)
1256 {
1257         u8 val;
1258
1259         val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1260
1261         switch (val) {
1262         case NET_DM_ALERT_MODE_SUMMARY:
1263         case NET_DM_ALERT_MODE_PACKET:
1264                 *p_alert_mode = val;
1265                 break;
1266         default:
1267                 return -EINVAL;
1268         }
1269
1270         return 0;
1271 }
1272
1273 static int net_dm_alert_mode_set(struct genl_info *info)
1274 {
1275         struct netlink_ext_ack *extack = info->extack;
1276         enum net_dm_alert_mode alert_mode;
1277         int rc;
1278
1279         if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1280                 return 0;
1281
1282         rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1283         if (rc) {
1284                 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1285                 return -EINVAL;
1286         }
1287
1288         net_dm_alert_mode = alert_mode;
1289
1290         return 0;
1291 }
1292
1293 static void net_dm_trunc_len_set(struct genl_info *info)
1294 {
1295         if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1296                 return;
1297
1298         net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1299 }
1300
1301 static void net_dm_queue_len_set(struct genl_info *info)
1302 {
1303         if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1304                 return;
1305
1306         net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1307 }
1308
1309 static int net_dm_cmd_config(struct sk_buff *skb,
1310                         struct genl_info *info)
1311 {
1312         struct netlink_ext_ack *extack = info->extack;
1313         int rc;
1314
1315         if (net_dm_is_monitoring()) {
1316                 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1317                 return -EBUSY;
1318         }
1319
1320         rc = net_dm_alert_mode_set(info);
1321         if (rc)
1322                 return rc;
1323
1324         net_dm_trunc_len_set(info);
1325
1326         net_dm_queue_len_set(info);
1327
1328         return 0;
1329 }
1330
1331 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1332                                 struct netlink_ext_ack *extack)
1333 {
1334         bool sw_set = false;
1335         int rc;
1336
1337         if (set_sw) {
1338                 rc = set_all_monitor_traces(TRACE_ON, extack);
1339                 if (rc)
1340                         return rc;
1341                 sw_set = true;
1342         }
1343
1344         if (set_hw) {
1345                 rc = net_dm_hw_monitor_start(extack);
1346                 if (rc)
1347                         goto err_monitor_hw;
1348         }
1349
1350         return 0;
1351
1352 err_monitor_hw:
1353         if (sw_set)
1354                 set_all_monitor_traces(TRACE_OFF, extack);
1355         return rc;
1356 }
1357
1358 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1359                                 struct netlink_ext_ack *extack)
1360 {
1361         if (set_hw)
1362                 net_dm_hw_monitor_stop(extack);
1363         if (set_sw)
1364                 set_all_monitor_traces(TRACE_OFF, extack);
1365 }
1366
1367 static int net_dm_cmd_trace(struct sk_buff *skb,
1368                         struct genl_info *info)
1369 {
1370         bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1371         bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1372         struct netlink_ext_ack *extack = info->extack;
1373
1374         /* To maintain backward compatibility, we start / stop monitoring of
1375          * software drops if no flag is specified.
1376          */
1377         if (!set_sw && !set_hw)
1378                 set_sw = true;
1379
1380         switch (info->genlhdr->cmd) {
1381         case NET_DM_CMD_START:
1382                 return net_dm_monitor_start(set_sw, set_hw, extack);
1383         case NET_DM_CMD_STOP:
1384                 net_dm_monitor_stop(set_sw, set_hw, extack);
1385                 return 0;
1386         }
1387
1388         return -EOPNOTSUPP;
1389 }
1390
1391 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1392 {
1393         void *hdr;
1394
1395         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1396                           &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1397         if (!hdr)
1398                 return -EMSGSIZE;
1399
1400         if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1401                 goto nla_put_failure;
1402
1403         if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1404                 goto nla_put_failure;
1405
1406         if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1407                 goto nla_put_failure;
1408
1409         genlmsg_end(msg, hdr);
1410
1411         return 0;
1412
1413 nla_put_failure:
1414         genlmsg_cancel(msg, hdr);
1415         return -EMSGSIZE;
1416 }
1417
1418 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1419 {
1420         struct sk_buff *msg;
1421         int rc;
1422
1423         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1424         if (!msg)
1425                 return -ENOMEM;
1426
1427         rc = net_dm_config_fill(msg, info);
1428         if (rc)
1429                 goto free_msg;
1430
1431         return genlmsg_reply(msg, info);
1432
1433 free_msg:
1434         nlmsg_free(msg);
1435         return rc;
1436 }
1437
1438 static void net_dm_stats_read(struct net_dm_stats *stats)
1439 {
1440         int cpu;
1441
1442         memset(stats, 0, sizeof(*stats));
1443         for_each_possible_cpu(cpu) {
1444                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1445                 struct net_dm_stats *cpu_stats = &data->stats;
1446                 unsigned int start;
1447                 u64 dropped;
1448
1449                 do {
1450                         start = u64_stats_fetch_begin(&cpu_stats->syncp);
1451                         dropped = u64_stats_read(&cpu_stats->dropped);
1452                 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1453
1454                 u64_stats_add(&stats->dropped, dropped);
1455         }
1456 }
1457
1458 static int net_dm_stats_put(struct sk_buff *msg)
1459 {
1460         struct net_dm_stats stats;
1461         struct nlattr *attr;
1462
1463         net_dm_stats_read(&stats);
1464
1465         attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1466         if (!attr)
1467                 return -EMSGSIZE;
1468
1469         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1470                               u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1471                 goto nla_put_failure;
1472
1473         nla_nest_end(msg, attr);
1474
1475         return 0;
1476
1477 nla_put_failure:
1478         nla_nest_cancel(msg, attr);
1479         return -EMSGSIZE;
1480 }
1481
1482 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1483 {
1484         int cpu;
1485
1486         memset(stats, 0, sizeof(*stats));
1487         for_each_possible_cpu(cpu) {
1488                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1489                 struct net_dm_stats *cpu_stats = &hw_data->stats;
1490                 unsigned int start;
1491                 u64 dropped;
1492
1493                 do {
1494                         start = u64_stats_fetch_begin(&cpu_stats->syncp);
1495                         dropped = u64_stats_read(&cpu_stats->dropped);
1496                 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start));
1497
1498                 u64_stats_add(&stats->dropped, dropped);
1499         }
1500 }
1501
1502 static int net_dm_hw_stats_put(struct sk_buff *msg)
1503 {
1504         struct net_dm_stats stats;
1505         struct nlattr *attr;
1506
1507         net_dm_hw_stats_read(&stats);
1508
1509         attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1510         if (!attr)
1511                 return -EMSGSIZE;
1512
1513         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1514                               u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD))
1515                 goto nla_put_failure;
1516
1517         nla_nest_end(msg, attr);
1518
1519         return 0;
1520
1521 nla_put_failure:
1522         nla_nest_cancel(msg, attr);
1523         return -EMSGSIZE;
1524 }
1525
1526 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1527 {
1528         void *hdr;
1529         int rc;
1530
1531         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1532                           &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1533         if (!hdr)
1534                 return -EMSGSIZE;
1535
1536         rc = net_dm_stats_put(msg);
1537         if (rc)
1538                 goto nla_put_failure;
1539
1540         rc = net_dm_hw_stats_put(msg);
1541         if (rc)
1542                 goto nla_put_failure;
1543
1544         genlmsg_end(msg, hdr);
1545
1546         return 0;
1547
1548 nla_put_failure:
1549         genlmsg_cancel(msg, hdr);
1550         return -EMSGSIZE;
1551 }
1552
1553 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1554 {
1555         struct sk_buff *msg;
1556         int rc;
1557
1558         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1559         if (!msg)
1560                 return -ENOMEM;
1561
1562         rc = net_dm_stats_fill(msg, info);
1563         if (rc)
1564                 goto free_msg;
1565
1566         return genlmsg_reply(msg, info);
1567
1568 free_msg:
1569         nlmsg_free(msg);
1570         return rc;
1571 }
1572
1573 static int dropmon_net_event(struct notifier_block *ev_block,
1574                              unsigned long event, void *ptr)
1575 {
1576         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1577         struct dm_hw_stat_delta *stat;
1578
1579         switch (event) {
1580         case NETDEV_REGISTER:
1581                 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1582                         break;
1583                 stat = kzalloc(sizeof(*stat), GFP_KERNEL);
1584                 if (!stat)
1585                         break;
1586
1587                 stat->last_rx = jiffies;
1588                 rcu_assign_pointer(dev->dm_private, stat);
1589
1590                 break;
1591         case NETDEV_UNREGISTER:
1592                 stat = rtnl_dereference(dev->dm_private);
1593                 if (stat) {
1594                         rcu_assign_pointer(dev->dm_private, NULL);
1595                         kfree_rcu(stat, rcu);
1596                 }
1597                 break;
1598         }
1599         return NOTIFY_DONE;
1600 }
1601
1602 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1603         [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1604         [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1605         [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1606         [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1607         [NET_DM_ATTR_SW_DROPS]  = {. type = NLA_FLAG },
1608         [NET_DM_ATTR_HW_DROPS]  = {. type = NLA_FLAG },
1609 };
1610
1611 static const struct genl_small_ops dropmon_ops[] = {
1612         {
1613                 .cmd = NET_DM_CMD_CONFIG,
1614                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1615                 .doit = net_dm_cmd_config,
1616                 .flags = GENL_ADMIN_PERM,
1617         },
1618         {
1619                 .cmd = NET_DM_CMD_START,
1620                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1621                 .doit = net_dm_cmd_trace,
1622         },
1623         {
1624                 .cmd = NET_DM_CMD_STOP,
1625                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1626                 .doit = net_dm_cmd_trace,
1627         },
1628         {
1629                 .cmd = NET_DM_CMD_CONFIG_GET,
1630                 .doit = net_dm_cmd_config_get,
1631         },
1632         {
1633                 .cmd = NET_DM_CMD_STATS_GET,
1634                 .doit = net_dm_cmd_stats_get,
1635         },
1636 };
1637
1638 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
1639                               struct sk_buff *skb, struct genl_info *info)
1640 {
1641         mutex_lock(&net_dm_mutex);
1642
1643         return 0;
1644 }
1645
1646 static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
1647                                 struct sk_buff *skb, struct genl_info *info)
1648 {
1649         mutex_unlock(&net_dm_mutex);
1650 }
1651
1652 static struct genl_family net_drop_monitor_family __ro_after_init = {
1653         .hdrsize        = 0,
1654         .name           = "NET_DM",
1655         .version        = 2,
1656         .maxattr        = NET_DM_ATTR_MAX,
1657         .policy         = net_dm_nl_policy,
1658         .pre_doit       = net_dm_nl_pre_doit,
1659         .post_doit      = net_dm_nl_post_doit,
1660         .module         = THIS_MODULE,
1661         .small_ops      = dropmon_ops,
1662         .n_small_ops    = ARRAY_SIZE(dropmon_ops),
1663         .resv_start_op  = NET_DM_CMD_STATS_GET + 1,
1664         .mcgrps         = dropmon_mcgrps,
1665         .n_mcgrps       = ARRAY_SIZE(dropmon_mcgrps),
1666 };
1667
1668 static struct notifier_block dropmon_net_notifier = {
1669         .notifier_call = dropmon_net_event
1670 };
1671
1672 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1673 {
1674         spin_lock_init(&data->lock);
1675         skb_queue_head_init(&data->drop_queue);
1676         u64_stats_init(&data->stats.syncp);
1677 }
1678
1679 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1680 {
1681         WARN_ON(!skb_queue_empty(&data->drop_queue));
1682 }
1683
1684 static void net_dm_cpu_data_init(int cpu)
1685 {
1686         struct per_cpu_dm_data *data;
1687
1688         data = &per_cpu(dm_cpu_data, cpu);
1689         __net_dm_cpu_data_init(data);
1690 }
1691
1692 static void net_dm_cpu_data_fini(int cpu)
1693 {
1694         struct per_cpu_dm_data *data;
1695
1696         data = &per_cpu(dm_cpu_data, cpu);
1697         /* At this point, we should have exclusive access
1698          * to this struct and can free the skb inside it.
1699          */
1700         consume_skb(data->skb);
1701         __net_dm_cpu_data_fini(data);
1702 }
1703
1704 static void net_dm_hw_cpu_data_init(int cpu)
1705 {
1706         struct per_cpu_dm_data *hw_data;
1707
1708         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1709         __net_dm_cpu_data_init(hw_data);
1710 }
1711
1712 static void net_dm_hw_cpu_data_fini(int cpu)
1713 {
1714         struct per_cpu_dm_data *hw_data;
1715
1716         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1717         kfree(hw_data->hw_entries);
1718         __net_dm_cpu_data_fini(hw_data);
1719 }
1720
1721 static int __init init_net_drop_monitor(void)
1722 {
1723         int cpu, rc;
1724
1725         pr_info("Initializing network drop monitor service\n");
1726
1727         if (sizeof(void *) > 8) {
1728                 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1729                 return -ENOSPC;
1730         }
1731
1732         rc = genl_register_family(&net_drop_monitor_family);
1733         if (rc) {
1734                 pr_err("Could not create drop monitor netlink family\n");
1735                 return rc;
1736         }
1737         WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1738
1739         rc = register_netdevice_notifier(&dropmon_net_notifier);
1740         if (rc < 0) {
1741                 pr_crit("Failed to register netdevice notifier\n");
1742                 goto out_unreg;
1743         }
1744
1745         rc = 0;
1746
1747         for_each_possible_cpu(cpu) {
1748                 net_dm_cpu_data_init(cpu);
1749                 net_dm_hw_cpu_data_init(cpu);
1750         }
1751
1752         goto out;
1753
1754 out_unreg:
1755         genl_unregister_family(&net_drop_monitor_family);
1756 out:
1757         return rc;
1758 }
1759
1760 static void exit_net_drop_monitor(void)
1761 {
1762         int cpu;
1763
1764         BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1765
1766         /*
1767          * Because of the module_get/put we do in the trace state change path
1768          * we are guaranteed not to have any current users when we get here
1769          */
1770
1771         for_each_possible_cpu(cpu) {
1772                 net_dm_hw_cpu_data_fini(cpu);
1773                 net_dm_cpu_data_fini(cpu);
1774         }
1775
1776         BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1777 }
1778
1779 module_init(init_net_drop_monitor);
1780 module_exit(exit_net_drop_monitor);
1781
1782 MODULE_LICENSE("GPL v2");
1783 MODULE_AUTHOR("Neil Horman <[email protected]>");
1784 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1785 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");