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 #undef EM
  52 #undef EMe
  53
  54 #define EM(a, b)        [a] = #b,
  55 #define EMe(a, b)       [a] = #b
  56
  57 /* drop_reasons is used to translate 'enum skb_drop_reason' to string,
  58  * which is reported to user space.
  59  */
  60 static const char * const drop_reasons[] = {
  61         TRACE_SKB_DROP_REASON
  62 };
  63
  64 /* net_dm_mutex
  65  *
  66  * An overall lock guarding every operation coming from userspace.
  67  */
  68 static DEFINE_MUTEX(net_dm_mutex);
  69
  70 struct net_dm_stats {
  71         u64 dropped;
  72         struct u64_stats_sync syncp;
  73 };
  74
  75 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
  76
  77 struct net_dm_hw_entry {
  78         char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  79         u32 count;
  80 };
  81
  82 struct net_dm_hw_entries {
  83         u32 num_entries;
  84         struct net_dm_hw_entry entries[];
  85 };
  86
  87 struct per_cpu_dm_data {
  88         spinlock_t              lock;   /* Protects 'skb', 'hw_entries' and
  89                                          * 'send_timer'
  90                                          */
  91         union {
  92                 struct sk_buff                  *skb;
  93                 struct net_dm_hw_entries        *hw_entries;
  94         };
  95         struct sk_buff_head     drop_queue;
  96         struct work_struct      dm_alert_work;
  97         struct timer_list       send_timer;
  98         struct net_dm_stats     stats;
  99 };
 100
 101 struct dm_hw_stat_delta {
 102         unsigned long last_rx;
 103         unsigned long last_drop_val;
 104         struct rcu_head rcu;
 105 };
 106
 107 static struct genl_family net_drop_monitor_family;
 108
 109 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
 110 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 111
 112 static int dm_hit_limit = 64;
 113 static int dm_delay = 1;
 114 static unsigned long dm_hw_check_delta = 2*HZ;
 115
 116 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 117 static u32 net_dm_trunc_len;
 118 static u32 net_dm_queue_len = 1000;
 119
 120 struct net_dm_alert_ops {
 121         void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
 122                                 void *location,
 123                                 enum skb_drop_reason reason);
 124         void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 125                                 int work, int budget);
 126         void (*work_item_func)(struct work_struct *work);
 127         void (*hw_work_item_func)(struct work_struct *work);
 128         void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
 129                               struct sk_buff *skb,
 130                               const struct devlink_trap_metadata *metadata);
 131 };
 132
 133 struct net_dm_skb_cb {
 134         union {
 135                 struct devlink_trap_metadata *hw_metadata;
 136                 void *pc;
 137         };
 138         enum skb_drop_reason reason;
 139 };
 140
 141 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
 142
 143 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 144 {
 145         size_t al;
 146         struct net_dm_alert_msg *msg;
 147         struct nlattr *nla;
 148         struct sk_buff *skb;
 149         unsigned long flags;
 150         void *msg_header;
 151
 152         al = sizeof(struct net_dm_alert_msg);
 153         al += dm_hit_limit * sizeof(struct net_dm_drop_point);
 154         al += sizeof(struct nlattr);
 155
 156         skb = genlmsg_new(al, GFP_KERNEL);
 157
 158         if (!skb)
 159                 goto err;
 160
 161         msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
 162                                  0, NET_DM_CMD_ALERT);
 163         if (!msg_header) {
 164                 nlmsg_free(skb);
 165                 skb = NULL;
 166                 goto err;
 167         }
 168         nla = nla_reserve(skb, NLA_UNSPEC,
 169                           sizeof(struct net_dm_alert_msg));
 170         if (!nla) {
 171                 nlmsg_free(skb);
 172                 skb = NULL;
 173                 goto err;
 174         }
 175         msg = nla_data(nla);
 176         memset(msg, 0, al);
 177         goto out;
 178
 179 err:
 180         mod_timer(&data->send_timer, jiffies + HZ / 10);
 181 out:
 182         spin_lock_irqsave(&data->lock, flags);
 183         swap(data->skb, skb);
 184         spin_unlock_irqrestore(&data->lock, flags);
 185
 186         if (skb) {
 187                 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
 188                 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
 189
 190                 genlmsg_end(skb, genlmsg_data(gnlh));
 191         }
 192
 193         return skb;
 194 }
 195
 196 static const struct genl_multicast_group dropmon_mcgrps[] = {
 197         { .name = "events", },
 198 };
 199
 200 static void send_dm_alert(struct work_struct *work)
 201 {
 202         struct sk_buff *skb;
 203         struct per_cpu_dm_data *data;
 204
 205         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 206
 207         skb = reset_per_cpu_data(data);
 208
 209         if (skb)
 210                 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
 211                                   0, GFP_KERNEL);
 212 }
 213
 214 /*
 215  * This is the timer function to delay the sending of an alert
 216  * in the event that more drops will arrive during the
 217  * hysteresis period.
 218  */
 219 static void sched_send_work(struct timer_list *t)
 220 {
 221         struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
 222
 223         schedule_work(&data->dm_alert_work);
 224 }
 225
 226 static void trace_drop_common(struct sk_buff *skb, void *location)
 227 {
 228         struct net_dm_alert_msg *msg;
 229         struct net_dm_drop_point *point;
 230         struct nlmsghdr *nlh;
 231         struct nlattr *nla;
 232         int i;
 233         struct sk_buff *dskb;
 234         struct per_cpu_dm_data *data;
 235         unsigned long flags;
 236
 237         local_irq_save(flags);
 238         data = this_cpu_ptr(&dm_cpu_data);
 239         spin_lock(&data->lock);
 240         dskb = data->skb;
 241
 242         if (!dskb)
 243                 goto out;
 244
 245         nlh = (struct nlmsghdr *)dskb->data;
 246         nla = genlmsg_data(nlmsg_data(nlh));
 247         msg = nla_data(nla);
 248         point = msg->points;
 249         for (i = 0; i < msg->entries; i++) {
 250                 if (!memcmp(&location, &point->pc, sizeof(void *))) {
 251                         point->count++;
 252                         goto out;
 253                 }
 254                 point++;
 255         }
 256         if (msg->entries == dm_hit_limit)
 257                 goto out;
 258         /*
 259          * We need to create a new entry
 260          */
 261         __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
 262         nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
 263         memcpy(point->pc, &location, sizeof(void *));
 264         point->count = 1;
 265         msg->entries++;
 266
 267         if (!timer_pending(&data->send_timer)) {
 268                 data->send_timer.expires = jiffies + dm_delay * HZ;
 269                 add_timer(&data->send_timer);
 270         }
 271
 272 out:
 273         spin_unlock_irqrestore(&data->lock, flags);
 274 }
 275
 276 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
 277                                 void *location,
 278                                 enum skb_drop_reason reason)
 279 {
 280         trace_drop_common(skb, location);
 281 }
 282
 283 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 284                                 int work, int budget)
 285 {
 286         struct net_device *dev = napi->dev;
 287         struct dm_hw_stat_delta *stat;
 288         /*
 289          * Don't check napi structures with no associated device
 290          */
 291         if (!dev)
 292                 return;
 293
 294         rcu_read_lock();
 295         stat = rcu_dereference(dev->dm_private);
 296         if (stat) {
 297                 /*
 298                  * only add a note to our monitor buffer if:
 299                  * 1) its after the last_rx delta
 300                  * 2) our rx_dropped count has gone up
 301                  */
 302                 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) &&
 303                     (dev->stats.rx_dropped != stat->last_drop_val)) {
 304                         trace_drop_common(NULL, NULL);
 305                         stat->last_drop_val = dev->stats.rx_dropped;
 306                         stat->last_rx = jiffies;
 307                 }
 308         }
 309         rcu_read_unlock();
 310 }
 311
 312 static struct net_dm_hw_entries *
 313 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 314 {
 315         struct net_dm_hw_entries *hw_entries;
 316         unsigned long flags;
 317
 318         hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
 319                              GFP_KERNEL);
 320         if (!hw_entries) {
 321                 /* If the memory allocation failed, we try to perform another
 322                  * allocation in 1/10 second. Otherwise, the probe function
 323                  * will constantly bail out.
 324                  */
 325                 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 326         }
 327
 328         spin_lock_irqsave(&hw_data->lock, flags);
 329         swap(hw_data->hw_entries, hw_entries);
 330         spin_unlock_irqrestore(&hw_data->lock, flags);
 331
 332         return hw_entries;
 333 }
 334
 335 static int net_dm_hw_entry_put(struct sk_buff *msg,
 336                                const struct net_dm_hw_entry *hw_entry)
 337 {
 338         struct nlattr *attr;
 339
 340         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
 341         if (!attr)
 342                 return -EMSGSIZE;
 343
 344         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
 345                 goto nla_put_failure;
 346
 347         if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
 348                 goto nla_put_failure;
 349
 350         nla_nest_end(msg, attr);
 351
 352         return 0;
 353
 354 nla_put_failure:
 355         nla_nest_cancel(msg, attr);
 356         return -EMSGSIZE;
 357 }
 358
 359 static int net_dm_hw_entries_put(struct sk_buff *msg,
 360                                  const struct net_dm_hw_entries *hw_entries)
 361 {
 362         struct nlattr *attr;
 363         int i;
 364
 365         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
 366         if (!attr)
 367                 return -EMSGSIZE;
 368
 369         for (i = 0; i < hw_entries->num_entries; i++) {
 370                 int rc;
 371
 372                 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
 373                 if (rc)
 374                         goto nla_put_failure;
 375         }
 376
 377         nla_nest_end(msg, attr);
 378
 379         return 0;
 380
 381 nla_put_failure:
 382         nla_nest_cancel(msg, attr);
 383         return -EMSGSIZE;
 384 }
 385
 386 static int
 387 net_dm_hw_summary_report_fill(struct sk_buff *msg,
 388                               const struct net_dm_hw_entries *hw_entries)
 389 {
 390         struct net_dm_alert_msg anc_hdr = { 0 };
 391         void *hdr;
 392         int rc;
 393
 394         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 395                           NET_DM_CMD_ALERT);
 396         if (!hdr)
 397                 return -EMSGSIZE;
 398
 399         /* We need to put the ancillary header in order not to break user
 400          * space.
 401          */
 402         if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
 403                 goto nla_put_failure;
 404
 405         rc = net_dm_hw_entries_put(msg, hw_entries);
 406         if (rc)
 407                 goto nla_put_failure;
 408
 409         genlmsg_end(msg, hdr);
 410
 411         return 0;
 412
 413 nla_put_failure:
 414         genlmsg_cancel(msg, hdr);
 415         return -EMSGSIZE;
 416 }
 417
 418 static void net_dm_hw_summary_work(struct work_struct *work)
 419 {
 420         struct net_dm_hw_entries *hw_entries;
 421         struct per_cpu_dm_data *hw_data;
 422         struct sk_buff *msg;
 423         int rc;
 424
 425         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 426
 427         hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
 428         if (!hw_entries)
 429                 return;
 430
 431         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 432         if (!msg)
 433                 goto out;
 434
 435         rc = net_dm_hw_summary_report_fill(msg, hw_entries);
 436         if (rc) {
 437                 nlmsg_free(msg);
 438                 goto out;
 439         }
 440
 441         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 442
 443 out:
 444         kfree(hw_entries);
 445 }
 446
 447 static void
 448 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
 449                              struct sk_buff *skb,
 450                              const struct devlink_trap_metadata *metadata)
 451 {
 452         struct net_dm_hw_entries *hw_entries;
 453         struct net_dm_hw_entry *hw_entry;
 454         struct per_cpu_dm_data *hw_data;
 455         unsigned long flags;
 456         int i;
 457
 458         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 459                 return;
 460
 461         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 462         spin_lock_irqsave(&hw_data->lock, flags);
 463         hw_entries = hw_data->hw_entries;
 464
 465         if (!hw_entries)
 466                 goto out;
 467
 468         for (i = 0; i < hw_entries->num_entries; i++) {
 469                 hw_entry = &hw_entries->entries[i];
 470                 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
 471                              NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
 472                         hw_entry->count++;
 473                         goto out;
 474                 }
 475         }
 476         if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
 477                 goto out;
 478
 479         hw_entry = &hw_entries->entries[hw_entries->num_entries];
 480         strlcpy(hw_entry->trap_name, metadata->trap_name,
 481                 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
 482         hw_entry->count = 1;
 483         hw_entries->num_entries++;
 484
 485         if (!timer_pending(&hw_data->send_timer)) {
 486                 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
 487                 add_timer(&hw_data->send_timer);
 488         }
 489
 490 out:
 491         spin_unlock_irqrestore(&hw_data->lock, flags);
 492 }
 493
 494 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 495         .kfree_skb_probe        = trace_kfree_skb_hit,
 496         .napi_poll_probe        = trace_napi_poll_hit,
 497         .work_item_func         = send_dm_alert,
 498         .hw_work_item_func      = net_dm_hw_summary_work,
 499         .hw_trap_probe          = net_dm_hw_trap_summary_probe,
 500 };
 501
 502 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 503                                               struct sk_buff *skb,
 504                                               void *location,
 505                                               enum skb_drop_reason reason)
 506 {
 507         ktime_t tstamp = ktime_get_real();
 508         struct per_cpu_dm_data *data;
 509         struct net_dm_skb_cb *cb;
 510         struct sk_buff *nskb;
 511         unsigned long flags;
 512
 513         if (!skb_mac_header_was_set(skb))
 514                 return;
 515
 516         nskb = skb_clone(skb, GFP_ATOMIC);
 517         if (!nskb)
 518                 return;
 519
 520         if (unlikely(reason >= SKB_DROP_REASON_MAX || reason <= 0))
 521                 reason = SKB_DROP_REASON_NOT_SPECIFIED;
 522         cb = NET_DM_SKB_CB(nskb);
 523         cb->reason = reason;
 524         cb->pc = location;
 525         /* Override the timestamp because we care about the time when the
 526          * packet was dropped.
 527          */
 528         nskb->tstamp = tstamp;
 529
 530         data = this_cpu_ptr(&dm_cpu_data);
 531
 532         spin_lock_irqsave(&data->drop_queue.lock, flags);
 533         if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
 534                 __skb_queue_tail(&data->drop_queue, nskb);
 535         else
 536                 goto unlock_free;
 537         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 538
 539         schedule_work(&data->dm_alert_work);
 540
 541         return;
 542
 543 unlock_free:
 544         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 545         u64_stats_update_begin(&data->stats.syncp);
 546         data->stats.dropped++;
 547         u64_stats_update_end(&data->stats.syncp);
 548         consume_skb(nskb);
 549 }
 550
 551 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
 552                                               struct napi_struct *napi,
 553                                               int work, int budget)
 554 {
 555 }
 556
 557 static size_t net_dm_in_port_size(void)
 558 {
 559                /* NET_DM_ATTR_IN_PORT nest */
 560         return nla_total_size(0) +
 561                /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
 562                nla_total_size(sizeof(u32)) +
 563                /* NET_DM_ATTR_PORT_NETDEV_NAME */
 564                nla_total_size(IFNAMSIZ + 1);
 565 }
 566
 567 #define NET_DM_MAX_SYMBOL_LEN 40
 568
 569 static size_t net_dm_packet_report_size(size_t payload_len,
 570                                         enum skb_drop_reason reason)
 571 {
 572         size_t size;
 573
 574         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 575
 576         return NLMSG_ALIGN(size) +
 577                /* NET_DM_ATTR_ORIGIN */
 578                nla_total_size(sizeof(u16)) +
 579                /* NET_DM_ATTR_PC */
 580                nla_total_size(sizeof(u64)) +
 581                /* NET_DM_ATTR_SYMBOL */
 582                nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
 583                /* NET_DM_ATTR_IN_PORT */
 584                net_dm_in_port_size() +
 585                /* NET_DM_ATTR_TIMESTAMP */
 586                nla_total_size(sizeof(u64)) +
 587                /* NET_DM_ATTR_ORIG_LEN */
 588                nla_total_size(sizeof(u32)) +
 589                /* NET_DM_ATTR_PROTO */
 590                nla_total_size(sizeof(u16)) +
 591                /* NET_DM_ATTR_REASON */
 592                nla_total_size(strlen(drop_reasons[reason]) + 1) +
 593                /* NET_DM_ATTR_PAYLOAD */
 594                nla_total_size(payload_len);
 595 }
 596
 597 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
 598                                             const char *name)
 599 {
 600         struct nlattr *attr;
 601
 602         attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
 603         if (!attr)
 604                 return -EMSGSIZE;
 605
 606         if (ifindex &&
 607             nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
 608                 goto nla_put_failure;
 609
 610         if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
 611                 goto nla_put_failure;
 612
 613         nla_nest_end(msg, attr);
 614
 615         return 0;
 616
 617 nla_put_failure:
 618         nla_nest_cancel(msg, attr);
 619         return -EMSGSIZE;
 620 }
 621
 622 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
 623                                      size_t payload_len)
 624 {
 625         struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb);
 626         char buf[NET_DM_MAX_SYMBOL_LEN];
 627         struct nlattr *attr;
 628         void *hdr;
 629         int rc;
 630
 631         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 632                           NET_DM_CMD_PACKET_ALERT);
 633         if (!hdr)
 634                 return -EMSGSIZE;
 635
 636         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
 637                 goto nla_put_failure;
 638
 639         if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc,
 640                               NET_DM_ATTR_PAD))
 641                 goto nla_put_failure;
 642
 643         if (nla_put_string(msg, NET_DM_ATTR_REASON,
 644                            drop_reasons[cb->reason]))
 645                 goto nla_put_failure;
 646
 647         snprintf(buf, sizeof(buf), "%pS", cb->pc);
 648         if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
 649                 goto nla_put_failure;
 650
 651         rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
 652         if (rc)
 653                 goto nla_put_failure;
 654
 655         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 656                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 657                 goto nla_put_failure;
 658
 659         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 660                 goto nla_put_failure;
 661
 662         if (!payload_len)
 663                 goto out;
 664
 665         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 666                 goto nla_put_failure;
 667
 668         attr = skb_put(msg, nla_total_size(payload_len));
 669         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 670         attr->nla_len = nla_attr_size(payload_len);
 671         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 672                 goto nla_put_failure;
 673
 674 out:
 675         genlmsg_end(msg, hdr);
 676
 677         return 0;
 678
 679 nla_put_failure:
 680         genlmsg_cancel(msg, hdr);
 681         return -EMSGSIZE;
 682 }
 683
 684 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
 685
 686 static void net_dm_packet_report(struct sk_buff *skb)
 687 {
 688         struct sk_buff *msg;
 689         size_t payload_len;
 690         int rc;
 691
 692         /* Make sure we start copying the packet from the MAC header */
 693         if (skb->data > skb_mac_header(skb))
 694                 skb_push(skb, skb->data - skb_mac_header(skb));
 695         else
 696                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 697
 698         /* Ensure packet fits inside a single netlink attribute */
 699         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 700         if (net_dm_trunc_len)
 701                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 702
 703         msg = nlmsg_new(net_dm_packet_report_size(payload_len,
 704                                                   NET_DM_SKB_CB(skb)->reason),
 705                         GFP_KERNEL);
 706         if (!msg)
 707                 goto out;
 708
 709         rc = net_dm_packet_report_fill(msg, skb, payload_len);
 710         if (rc) {
 711                 nlmsg_free(msg);
 712                 goto out;
 713         }
 714
 715         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 716
 717 out:
 718         consume_skb(skb);
 719 }
 720
 721 static void net_dm_packet_work(struct work_struct *work)
 722 {
 723         struct per_cpu_dm_data *data;
 724         struct sk_buff_head list;
 725         struct sk_buff *skb;
 726         unsigned long flags;
 727
 728         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 729
 730         __skb_queue_head_init(&list);
 731
 732         spin_lock_irqsave(&data->drop_queue.lock, flags);
 733         skb_queue_splice_tail_init(&data->drop_queue, &list);
 734         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 735
 736         while ((skb = __skb_dequeue(&list)))
 737                 net_dm_packet_report(skb);
 738 }
 739
 740 static size_t
 741 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
 742 {
 743         return hw_metadata->fa_cookie ?
 744                nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
 745 }
 746
 747 static size_t
 748 net_dm_hw_packet_report_size(size_t payload_len,
 749                              const struct devlink_trap_metadata *hw_metadata)
 750 {
 751         size_t size;
 752
 753         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 754
 755         return NLMSG_ALIGN(size) +
 756                /* NET_DM_ATTR_ORIGIN */
 757                nla_total_size(sizeof(u16)) +
 758                /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
 759                nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
 760                /* NET_DM_ATTR_HW_TRAP_NAME */
 761                nla_total_size(strlen(hw_metadata->trap_name) + 1) +
 762                /* NET_DM_ATTR_IN_PORT */
 763                net_dm_in_port_size() +
 764                /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
 765                net_dm_flow_action_cookie_size(hw_metadata) +
 766                /* NET_DM_ATTR_TIMESTAMP */
 767                nla_total_size(sizeof(u64)) +
 768                /* NET_DM_ATTR_ORIG_LEN */
 769                nla_total_size(sizeof(u32)) +
 770                /* NET_DM_ATTR_PROTO */
 771                nla_total_size(sizeof(u16)) +
 772                /* NET_DM_ATTR_PAYLOAD */
 773                nla_total_size(payload_len);
 774 }
 775
 776 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 777                                         struct sk_buff *skb, size_t payload_len)
 778 {
 779         struct devlink_trap_metadata *hw_metadata;
 780         struct nlattr *attr;
 781         void *hdr;
 782
 783         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 784
 785         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 786                           NET_DM_CMD_PACKET_ALERT);
 787         if (!hdr)
 788                 return -EMSGSIZE;
 789
 790         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
 791                 goto nla_put_failure;
 792
 793         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
 794                            hw_metadata->trap_group_name))
 795                 goto nla_put_failure;
 796
 797         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
 798                            hw_metadata->trap_name))
 799                 goto nla_put_failure;
 800
 801         if (hw_metadata->input_dev) {
 802                 struct net_device *dev = hw_metadata->input_dev;
 803                 int rc;
 804
 805                 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
 806                                                       dev->name);
 807                 if (rc)
 808                         goto nla_put_failure;
 809         }
 810
 811         if (hw_metadata->fa_cookie &&
 812             nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
 813                     hw_metadata->fa_cookie->cookie_len,
 814                     hw_metadata->fa_cookie->cookie))
 815                 goto nla_put_failure;
 816
 817         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 818                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 819                 goto nla_put_failure;
 820
 821         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 822                 goto nla_put_failure;
 823
 824         if (!payload_len)
 825                 goto out;
 826
 827         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 828                 goto nla_put_failure;
 829
 830         attr = skb_put(msg, nla_total_size(payload_len));
 831         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 832         attr->nla_len = nla_attr_size(payload_len);
 833         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 834                 goto nla_put_failure;
 835
 836 out:
 837         genlmsg_end(msg, hdr);
 838
 839         return 0;
 840
 841 nla_put_failure:
 842         genlmsg_cancel(msg, hdr);
 843         return -EMSGSIZE;
 844 }
 845
 846 static struct devlink_trap_metadata *
 847 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
 848 {
 849         const struct flow_action_cookie *fa_cookie;
 850         struct devlink_trap_metadata *hw_metadata;
 851         const char *trap_group_name;
 852         const char *trap_name;
 853
 854         hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
 855         if (!hw_metadata)
 856                 return NULL;
 857
 858         trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
 859         if (!trap_group_name)
 860                 goto free_hw_metadata;
 861         hw_metadata->trap_group_name = trap_group_name;
 862
 863         trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
 864         if (!trap_name)
 865                 goto free_trap_group;
 866         hw_metadata->trap_name = trap_name;
 867
 868         if (metadata->fa_cookie) {
 869                 size_t cookie_size = sizeof(*fa_cookie) +
 870                                      metadata->fa_cookie->cookie_len;
 871
 872                 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
 873                                     GFP_ATOMIC);
 874                 if (!fa_cookie)
 875                         goto free_trap_name;
 876                 hw_metadata->fa_cookie = fa_cookie;
 877         }
 878
 879         hw_metadata->input_dev = metadata->input_dev;
 880         dev_hold_track(hw_metadata->input_dev, &hw_metadata->dev_tracker, GFP_ATOMIC);
 881
 882         return hw_metadata;
 883
 884 free_trap_name:
 885         kfree(trap_name);
 886 free_trap_group:
 887         kfree(trap_group_name);
 888 free_hw_metadata:
 889         kfree(hw_metadata);
 890         return NULL;
 891 }
 892
 893 static void
 894 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata)
 895 {
 896         dev_put_track(hw_metadata->input_dev, &hw_metadata->dev_tracker);
 897         kfree(hw_metadata->fa_cookie);
 898         kfree(hw_metadata->trap_name);
 899         kfree(hw_metadata->trap_group_name);
 900         kfree(hw_metadata);
 901 }
 902
 903 static void net_dm_hw_packet_report(struct sk_buff *skb)
 904 {
 905         struct devlink_trap_metadata *hw_metadata;
 906         struct sk_buff *msg;
 907         size_t payload_len;
 908         int rc;
 909
 910         if (skb->data > skb_mac_header(skb))
 911                 skb_push(skb, skb->data - skb_mac_header(skb));
 912         else
 913                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 914
 915         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 916         if (net_dm_trunc_len)
 917                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 918
 919         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 920         msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
 921                         GFP_KERNEL);
 922         if (!msg)
 923                 goto out;
 924
 925         rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
 926         if (rc) {
 927                 nlmsg_free(msg);
 928                 goto out;
 929         }
 930
 931         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 932
 933 out:
 934         net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 935         consume_skb(skb);
 936 }
 937
 938 static void net_dm_hw_packet_work(struct work_struct *work)
 939 {
 940         struct per_cpu_dm_data *hw_data;
 941         struct sk_buff_head list;
 942         struct sk_buff *skb;
 943         unsigned long flags;
 944
 945         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 946
 947         __skb_queue_head_init(&list);
 948
 949         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 950         skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
 951         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 952
 953         while ((skb = __skb_dequeue(&list)))
 954                 net_dm_hw_packet_report(skb);
 955 }
 956
 957 static void
 958 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
 959                             struct sk_buff *skb,
 960                             const struct devlink_trap_metadata *metadata)
 961 {
 962         struct devlink_trap_metadata *n_hw_metadata;
 963         ktime_t tstamp = ktime_get_real();
 964         struct per_cpu_dm_data *hw_data;
 965         struct sk_buff *nskb;
 966         unsigned long flags;
 967
 968         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 969                 return;
 970
 971         if (!skb_mac_header_was_set(skb))
 972                 return;
 973
 974         nskb = skb_clone(skb, GFP_ATOMIC);
 975         if (!nskb)
 976                 return;
 977
 978         n_hw_metadata = net_dm_hw_metadata_copy(metadata);
 979         if (!n_hw_metadata)
 980                 goto free;
 981
 982         NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
 983         nskb->tstamp = tstamp;
 984
 985         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 986
 987         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 988         if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
 989                 __skb_queue_tail(&hw_data->drop_queue, nskb);
 990         else
 991                 goto unlock_free;
 992         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 993
 994         schedule_work(&hw_data->dm_alert_work);
 995
 996         return;
 997
 998 unlock_free:
 999         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
1000         u64_stats_update_begin(&hw_data->stats.syncp);
1001         hw_data->stats.dropped++;
1002         u64_stats_update_end(&hw_data->stats.syncp);
1003         net_dm_hw_metadata_free(n_hw_metadata);
1004 free:
1005         consume_skb(nskb);
1006 }
1007
1008 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
1009         .kfree_skb_probe        = net_dm_packet_trace_kfree_skb_hit,
1010         .napi_poll_probe        = net_dm_packet_trace_napi_poll_hit,
1011         .work_item_func         = net_dm_packet_work,
1012         .hw_work_item_func      = net_dm_hw_packet_work,
1013         .hw_trap_probe          = net_dm_hw_trap_packet_probe,
1014 };
1015
1016 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
1017         [NET_DM_ALERT_MODE_SUMMARY]     = &net_dm_alert_summary_ops,
1018         [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
1019 };
1020
1021 #if IS_ENABLED(CONFIG_NET_DEVLINK)
1022 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1023 {
1024         return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1025 }
1026
1027 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1028 {
1029         unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1030         tracepoint_synchronize_unregister();
1031 }
1032 #else
1033 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1034 {
1035         return -EOPNOTSUPP;
1036 }
1037
1038 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1039 {
1040 }
1041 #endif
1042
1043 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1044 {
1045         const struct net_dm_alert_ops *ops;
1046         int cpu, rc;
1047
1048         if (monitor_hw) {
1049                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1050                 return -EAGAIN;
1051         }
1052
1053         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1054
1055         if (!try_module_get(THIS_MODULE)) {
1056                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1057                 return -ENODEV;
1058         }
1059
1060         for_each_possible_cpu(cpu) {
1061                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1062                 struct net_dm_hw_entries *hw_entries;
1063
1064                 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1065                 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1066                 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1067                 kfree(hw_entries);
1068         }
1069
1070         rc = net_dm_hw_probe_register(ops);
1071         if (rc) {
1072                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1073                 goto err_module_put;
1074         }
1075
1076         monitor_hw = true;
1077
1078         return 0;
1079
1080 err_module_put:
1081         for_each_possible_cpu(cpu) {
1082                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1083                 struct sk_buff *skb;
1084
1085                 del_timer_sync(&hw_data->send_timer);
1086                 cancel_work_sync(&hw_data->dm_alert_work);
1087                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1088                         struct devlink_trap_metadata *hw_metadata;
1089
1090                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1091                         net_dm_hw_metadata_free(hw_metadata);
1092                         consume_skb(skb);
1093                 }
1094         }
1095         module_put(THIS_MODULE);
1096         return rc;
1097 }
1098
1099 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1100 {
1101         const struct net_dm_alert_ops *ops;
1102         int cpu;
1103
1104         if (!monitor_hw) {
1105                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1106                 return;
1107         }
1108
1109         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1110
1111         monitor_hw = false;
1112
1113         net_dm_hw_probe_unregister(ops);
1114
1115         for_each_possible_cpu(cpu) {
1116                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1117                 struct sk_buff *skb;
1118
1119                 del_timer_sync(&hw_data->send_timer);
1120                 cancel_work_sync(&hw_data->dm_alert_work);
1121                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1122                         struct devlink_trap_metadata *hw_metadata;
1123
1124                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1125                         net_dm_hw_metadata_free(hw_metadata);
1126                         consume_skb(skb);
1127                 }
1128         }
1129
1130         module_put(THIS_MODULE);
1131 }
1132
1133 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1134 {
1135         const struct net_dm_alert_ops *ops;
1136         int cpu, rc;
1137
1138         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1139
1140         if (!try_module_get(THIS_MODULE)) {
1141                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1142                 return -ENODEV;
1143         }
1144
1145         for_each_possible_cpu(cpu) {
1146                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1147                 struct sk_buff *skb;
1148
1149                 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1150                 timer_setup(&data->send_timer, sched_send_work, 0);
1151                 /* Allocate a new per-CPU skb for the summary alert message and
1152                  * free the old one which might contain stale data from
1153                  * previous tracing.
1154                  */
1155                 skb = reset_per_cpu_data(data);
1156                 consume_skb(skb);
1157         }
1158
1159         rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1160         if (rc) {
1161                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1162                 goto err_module_put;
1163         }
1164
1165         rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1166         if (rc) {
1167                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1168                 goto err_unregister_trace;
1169         }
1170
1171         return 0;
1172
1173 err_unregister_trace:
1174         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1175 err_module_put:
1176         for_each_possible_cpu(cpu) {
1177                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1178                 struct sk_buff *skb;
1179
1180                 del_timer_sync(&data->send_timer);
1181                 cancel_work_sync(&data->dm_alert_work);
1182                 while ((skb = __skb_dequeue(&data->drop_queue)))
1183                         consume_skb(skb);
1184         }
1185         module_put(THIS_MODULE);
1186         return rc;
1187 }
1188
1189 static void net_dm_trace_off_set(void)
1190 {
1191         const struct net_dm_alert_ops *ops;
1192         int cpu;
1193
1194         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1195
1196         unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1197         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1198
1199         tracepoint_synchronize_unregister();
1200
1201         /* Make sure we do not send notifications to user space after request
1202          * to stop tracing returns.
1203          */
1204         for_each_possible_cpu(cpu) {
1205                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1206                 struct sk_buff *skb;
1207
1208                 del_timer_sync(&data->send_timer);
1209                 cancel_work_sync(&data->dm_alert_work);
1210                 while ((skb = __skb_dequeue(&data->drop_queue)))
1211                         consume_skb(skb);
1212         }
1213
1214         module_put(THIS_MODULE);
1215 }
1216
1217 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1218 {
1219         int rc = 0;
1220
1221         if (state == trace_state) {
1222                 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1223                 return -EAGAIN;
1224         }
1225
1226         switch (state) {
1227         case TRACE_ON:
1228                 rc = net_dm_trace_on_set(extack);
1229                 break;
1230         case TRACE_OFF:
1231                 net_dm_trace_off_set();
1232                 break;
1233         default:
1234                 rc = 1;
1235                 break;
1236         }
1237
1238         if (!rc)
1239                 trace_state = state;
1240         else
1241                 rc = -EINPROGRESS;
1242
1243         return rc;
1244 }
1245
1246 static bool net_dm_is_monitoring(void)
1247 {
1248         return trace_state == TRACE_ON || monitor_hw;
1249 }
1250
1251 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1252                                            enum net_dm_alert_mode *p_alert_mode)
1253 {
1254         u8 val;
1255
1256         val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1257
1258         switch (val) {
1259         case NET_DM_ALERT_MODE_SUMMARY:
1260         case NET_DM_ALERT_MODE_PACKET:
1261                 *p_alert_mode = val;
1262                 break;
1263         default:
1264                 return -EINVAL;
1265         }
1266
1267         return 0;
1268 }
1269
1270 static int net_dm_alert_mode_set(struct genl_info *info)
1271 {
1272         struct netlink_ext_ack *extack = info->extack;
1273         enum net_dm_alert_mode alert_mode;
1274         int rc;
1275
1276         if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1277                 return 0;
1278
1279         rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1280         if (rc) {
1281                 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1282                 return -EINVAL;
1283         }
1284
1285         net_dm_alert_mode = alert_mode;
1286
1287         return 0;
1288 }
1289
1290 static void net_dm_trunc_len_set(struct genl_info *info)
1291 {
1292         if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1293                 return;
1294
1295         net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1296 }
1297
1298 static void net_dm_queue_len_set(struct genl_info *info)
1299 {
1300         if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1301                 return;
1302
1303         net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1304 }
1305
1306 static int net_dm_cmd_config(struct sk_buff *skb,
1307                         struct genl_info *info)
1308 {
1309         struct netlink_ext_ack *extack = info->extack;
1310         int rc;
1311
1312         if (net_dm_is_monitoring()) {
1313                 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1314                 return -EBUSY;
1315         }
1316
1317         rc = net_dm_alert_mode_set(info);
1318         if (rc)
1319                 return rc;
1320
1321         net_dm_trunc_len_set(info);
1322
1323         net_dm_queue_len_set(info);
1324
1325         return 0;
1326 }
1327
1328 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1329                                 struct netlink_ext_ack *extack)
1330 {
1331         bool sw_set = false;
1332         int rc;
1333
1334         if (set_sw) {
1335                 rc = set_all_monitor_traces(TRACE_ON, extack);
1336                 if (rc)
1337                         return rc;
1338                 sw_set = true;
1339         }
1340
1341         if (set_hw) {
1342                 rc = net_dm_hw_monitor_start(extack);
1343                 if (rc)
1344                         goto err_monitor_hw;
1345         }
1346
1347         return 0;
1348
1349 err_monitor_hw:
1350         if (sw_set)
1351                 set_all_monitor_traces(TRACE_OFF, extack);
1352         return rc;
1353 }
1354
1355 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1356                                 struct netlink_ext_ack *extack)
1357 {
1358         if (set_hw)
1359                 net_dm_hw_monitor_stop(extack);
1360         if (set_sw)
1361                 set_all_monitor_traces(TRACE_OFF, extack);
1362 }
1363
1364 static int net_dm_cmd_trace(struct sk_buff *skb,
1365                         struct genl_info *info)
1366 {
1367         bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1368         bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1369         struct netlink_ext_ack *extack = info->extack;
1370
1371         /* To maintain backward compatibility, we start / stop monitoring of
1372          * software drops if no flag is specified.
1373          */
1374         if (!set_sw && !set_hw)
1375                 set_sw = true;
1376
1377         switch (info->genlhdr->cmd) {
1378         case NET_DM_CMD_START:
1379                 return net_dm_monitor_start(set_sw, set_hw, extack);
1380         case NET_DM_CMD_STOP:
1381                 net_dm_monitor_stop(set_sw, set_hw, extack);
1382                 return 0;
1383         }
1384
1385         return -EOPNOTSUPP;
1386 }
1387
1388 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1389 {
1390         void *hdr;
1391
1392         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1393                           &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1394         if (!hdr)
1395                 return -EMSGSIZE;
1396
1397         if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1398                 goto nla_put_failure;
1399
1400         if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1401                 goto nla_put_failure;
1402
1403         if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1404                 goto nla_put_failure;
1405
1406         genlmsg_end(msg, hdr);
1407
1408         return 0;
1409
1410 nla_put_failure:
1411         genlmsg_cancel(msg, hdr);
1412         return -EMSGSIZE;
1413 }
1414
1415 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1416 {
1417         struct sk_buff *msg;
1418         int rc;
1419
1420         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1421         if (!msg)
1422                 return -ENOMEM;
1423
1424         rc = net_dm_config_fill(msg, info);
1425         if (rc)
1426                 goto free_msg;
1427
1428         return genlmsg_reply(msg, info);
1429
1430 free_msg:
1431         nlmsg_free(msg);
1432         return rc;
1433 }
1434
1435 static void net_dm_stats_read(struct net_dm_stats *stats)
1436 {
1437         int cpu;
1438
1439         memset(stats, 0, sizeof(*stats));
1440         for_each_possible_cpu(cpu) {
1441                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1442                 struct net_dm_stats *cpu_stats = &data->stats;
1443                 unsigned int start;
1444                 u64 dropped;
1445
1446                 do {
1447                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1448                         dropped = cpu_stats->dropped;
1449                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1450
1451                 stats->dropped += dropped;
1452         }
1453 }
1454
1455 static int net_dm_stats_put(struct sk_buff *msg)
1456 {
1457         struct net_dm_stats stats;
1458         struct nlattr *attr;
1459
1460         net_dm_stats_read(&stats);
1461
1462         attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1463         if (!attr)
1464                 return -EMSGSIZE;
1465
1466         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1467                               stats.dropped, NET_DM_ATTR_PAD))
1468                 goto nla_put_failure;
1469
1470         nla_nest_end(msg, attr);
1471
1472         return 0;
1473
1474 nla_put_failure:
1475         nla_nest_cancel(msg, attr);
1476         return -EMSGSIZE;
1477 }
1478
1479 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1480 {
1481         int cpu;
1482
1483         memset(stats, 0, sizeof(*stats));
1484         for_each_possible_cpu(cpu) {
1485                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1486                 struct net_dm_stats *cpu_stats = &hw_data->stats;
1487                 unsigned int start;
1488                 u64 dropped;
1489
1490                 do {
1491                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1492                         dropped = cpu_stats->dropped;
1493                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1494
1495                 stats->dropped += dropped;
1496         }
1497 }
1498
1499 static int net_dm_hw_stats_put(struct sk_buff *msg)
1500 {
1501         struct net_dm_stats stats;
1502         struct nlattr *attr;
1503
1504         net_dm_hw_stats_read(&stats);
1505
1506         attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1507         if (!attr)
1508                 return -EMSGSIZE;
1509
1510         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1511                               stats.dropped, NET_DM_ATTR_PAD))
1512                 goto nla_put_failure;
1513
1514         nla_nest_end(msg, attr);
1515
1516         return 0;
1517
1518 nla_put_failure:
1519         nla_nest_cancel(msg, attr);
1520         return -EMSGSIZE;
1521 }
1522
1523 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1524 {
1525         void *hdr;
1526         int rc;
1527
1528         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1529                           &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1530         if (!hdr)
1531                 return -EMSGSIZE;
1532
1533         rc = net_dm_stats_put(msg);
1534         if (rc)
1535                 goto nla_put_failure;
1536
1537         rc = net_dm_hw_stats_put(msg);
1538         if (rc)
1539                 goto nla_put_failure;
1540
1541         genlmsg_end(msg, hdr);
1542
1543         return 0;
1544
1545 nla_put_failure:
1546         genlmsg_cancel(msg, hdr);
1547         return -EMSGSIZE;
1548 }
1549
1550 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1551 {
1552         struct sk_buff *msg;
1553         int rc;
1554
1555         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1556         if (!msg)
1557                 return -ENOMEM;
1558
1559         rc = net_dm_stats_fill(msg, info);
1560         if (rc)
1561                 goto free_msg;
1562
1563         return genlmsg_reply(msg, info);
1564
1565 free_msg:
1566         nlmsg_free(msg);
1567         return rc;
1568 }
1569
1570 static int dropmon_net_event(struct notifier_block *ev_block,
1571                              unsigned long event, void *ptr)
1572 {
1573         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1574         struct dm_hw_stat_delta *stat;
1575
1576         switch (event) {
1577         case NETDEV_REGISTER:
1578                 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private)))
1579                         break;
1580                 stat = kzalloc(sizeof(*stat), GFP_KERNEL);
1581                 if (!stat)
1582                         break;
1583
1584                 stat->last_rx = jiffies;
1585                 rcu_assign_pointer(dev->dm_private, stat);
1586
1587                 break;
1588         case NETDEV_UNREGISTER:
1589                 stat = rtnl_dereference(dev->dm_private);
1590                 if (stat) {
1591                         rcu_assign_pointer(dev->dm_private, NULL);
1592                         kfree_rcu(stat, rcu);
1593                 }
1594                 break;
1595         }
1596         return NOTIFY_DONE;
1597 }
1598
1599 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1600         [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1601         [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1602         [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1603         [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1604         [NET_DM_ATTR_SW_DROPS]  = {. type = NLA_FLAG },
1605         [NET_DM_ATTR_HW_DROPS]  = {. type = NLA_FLAG },
1606 };
1607
1608 static const struct genl_small_ops dropmon_ops[] = {
1609         {
1610                 .cmd = NET_DM_CMD_CONFIG,
1611                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1612                 .doit = net_dm_cmd_config,
1613                 .flags = GENL_ADMIN_PERM,
1614         },
1615         {
1616                 .cmd = NET_DM_CMD_START,
1617                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1618                 .doit = net_dm_cmd_trace,
1619         },
1620         {
1621                 .cmd = NET_DM_CMD_STOP,
1622                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1623                 .doit = net_dm_cmd_trace,
1624         },
1625         {
1626                 .cmd = NET_DM_CMD_CONFIG_GET,
1627                 .doit = net_dm_cmd_config_get,
1628         },
1629         {
1630                 .cmd = NET_DM_CMD_STATS_GET,
1631                 .doit = net_dm_cmd_stats_get,
1632         },
1633 };
1634
1635 static int net_dm_nl_pre_doit(const struct genl_ops *ops,
1636                               struct sk_buff *skb, struct genl_info *info)
1637 {
1638         mutex_lock(&net_dm_mutex);
1639
1640         return 0;
1641 }
1642
1643 static void net_dm_nl_post_doit(const struct genl_ops *ops,
1644                                 struct sk_buff *skb, struct genl_info *info)
1645 {
1646         mutex_unlock(&net_dm_mutex);
1647 }
1648
1649 static struct genl_family net_drop_monitor_family __ro_after_init = {
1650         .hdrsize        = 0,
1651         .name           = "NET_DM",
1652         .version        = 2,
1653         .maxattr        = NET_DM_ATTR_MAX,
1654         .policy         = net_dm_nl_policy,
1655         .pre_doit       = net_dm_nl_pre_doit,
1656         .post_doit      = net_dm_nl_post_doit,
1657         .module         = THIS_MODULE,
1658         .small_ops      = dropmon_ops,
1659         .n_small_ops    = ARRAY_SIZE(dropmon_ops),
1660         .mcgrps         = dropmon_mcgrps,
1661         .n_mcgrps       = ARRAY_SIZE(dropmon_mcgrps),
1662 };
1663
1664 static struct notifier_block dropmon_net_notifier = {
1665         .notifier_call = dropmon_net_event
1666 };
1667
1668 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1669 {
1670         spin_lock_init(&data->lock);
1671         skb_queue_head_init(&data->drop_queue);
1672         u64_stats_init(&data->stats.syncp);
1673 }
1674
1675 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1676 {
1677         WARN_ON(!skb_queue_empty(&data->drop_queue));
1678 }
1679
1680 static void net_dm_cpu_data_init(int cpu)
1681 {
1682         struct per_cpu_dm_data *data;
1683
1684         data = &per_cpu(dm_cpu_data, cpu);
1685         __net_dm_cpu_data_init(data);
1686 }
1687
1688 static void net_dm_cpu_data_fini(int cpu)
1689 {
1690         struct per_cpu_dm_data *data;
1691
1692         data = &per_cpu(dm_cpu_data, cpu);
1693         /* At this point, we should have exclusive access
1694          * to this struct and can free the skb inside it.
1695          */
1696         consume_skb(data->skb);
1697         __net_dm_cpu_data_fini(data);
1698 }
1699
1700 static void net_dm_hw_cpu_data_init(int cpu)
1701 {
1702         struct per_cpu_dm_data *hw_data;
1703
1704         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1705         __net_dm_cpu_data_init(hw_data);
1706 }
1707
1708 static void net_dm_hw_cpu_data_fini(int cpu)
1709 {
1710         struct per_cpu_dm_data *hw_data;
1711
1712         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1713         kfree(hw_data->hw_entries);
1714         __net_dm_cpu_data_fini(hw_data);
1715 }
1716
1717 static int __init init_net_drop_monitor(void)
1718 {
1719         int cpu, rc;
1720
1721         pr_info("Initializing network drop monitor service\n");
1722
1723         if (sizeof(void *) > 8) {
1724                 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1725                 return -ENOSPC;
1726         }
1727
1728         rc = genl_register_family(&net_drop_monitor_family);
1729         if (rc) {
1730                 pr_err("Could not create drop monitor netlink family\n");
1731                 return rc;
1732         }
1733         WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1734
1735         rc = register_netdevice_notifier(&dropmon_net_notifier);
1736         if (rc < 0) {
1737                 pr_crit("Failed to register netdevice notifier\n");
1738                 goto out_unreg;
1739         }
1740
1741         rc = 0;
1742
1743         for_each_possible_cpu(cpu) {
1744                 net_dm_cpu_data_init(cpu);
1745                 net_dm_hw_cpu_data_init(cpu);
1746         }
1747
1748         goto out;
1749
1750 out_unreg:
1751         genl_unregister_family(&net_drop_monitor_family);
1752 out:
1753         return rc;
1754 }
1755
1756 static void exit_net_drop_monitor(void)
1757 {
1758         int cpu;
1759
1760         BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1761
1762         /*
1763          * Because of the module_get/put we do in the trace state change path
1764          * we are guaranteed not to have any current users when we get here
1765          */
1766
1767         for_each_possible_cpu(cpu) {
1768                 net_dm_hw_cpu_data_fini(cpu);
1769                 net_dm_cpu_data_fini(cpu);
1770         }
1771
1772         BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1773 }
1774
1775 module_init(init_net_drop_monitor);
1776 module_exit(exit_net_drop_monitor);
1777
1778 MODULE_LICENSE("GPL v2");
1779 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1780 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1781 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");