net/core/drop_monitor.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Monitoring code for network dropped packet alerts
   4  *
   5  * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/netdevice.h>
  11 #include <linux/etherdevice.h>
  12 #include <linux/string.h>
  13 #include <linux/if_arp.h>
  14 #include <linux/inetdevice.h>
  15 #include <linux/inet.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/netpoll.h>
  18 #include <linux/sched.h>
  19 #include <linux/delay.h>
  20 #include <linux/types.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/netlink.h>
  23 #include <linux/net_dropmon.h>
  24 #include <linux/percpu.h>
  25 #include <linux/timer.h>
  26 #include <linux/bitops.h>
  27 #include <linux/slab.h>
  28 #include <linux/module.h>
  29 #include <net/genetlink.h>
  30 #include <net/netevent.h>
  31 #include <net/flow_offload.h>
  32 #include <net/devlink.h>
  33
  34 #include <trace/events/skb.h>
  35 #include <trace/events/napi.h>
  36 #include <trace/events/devlink.h>
  37
  38 #include <asm/unaligned.h>
  39
  40 #define TRACE_ON 1
  41 #define TRACE_OFF 0
  42
  43 /*
  44  * Globals, our netlink socket pointer
  45  * and the work handle that will send up
  46  * netlink alerts
  47  */
  48 static int trace_state = TRACE_OFF;
  49 static bool monitor_hw;
  50
  51 /* net_dm_mutex
  52  *
  53  * An overall lock guarding every operation coming from userspace.
  54  * It also guards the global 'hw_stats_list' list.
  55  */
  56 static DEFINE_MUTEX(net_dm_mutex);
  57
  58 struct net_dm_stats {
  59         u64 dropped;
  60         struct u64_stats_sync syncp;
  61 };
  62
  63 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40
  64
  65 struct net_dm_hw_entry {
  66         char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  67         u32 count;
  68 };
  69
  70 struct net_dm_hw_entries {
  71         u32 num_entries;
  72         struct net_dm_hw_entry entries[];
  73 };
  74
  75 struct per_cpu_dm_data {
  76         spinlock_t              lock;   /* Protects 'skb', 'hw_entries' and
  77                                          * 'send_timer'
  78                                          */
  79         union {
  80                 struct sk_buff                  *skb;
  81                 struct net_dm_hw_entries        *hw_entries;
  82         };
  83         struct sk_buff_head     drop_queue;
  84         struct work_struct      dm_alert_work;
  85         struct timer_list       send_timer;
  86         struct net_dm_stats     stats;
  87 };
  88
  89 struct dm_hw_stat_delta {
  90         struct net_device *dev;
  91         unsigned long last_rx;
  92         struct list_head list;
  93         struct rcu_head rcu;
  94         unsigned long last_drop_val;
  95 };
  96
  97 static struct genl_family net_drop_monitor_family;
  98
  99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
 100 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 101
 102 static int dm_hit_limit = 64;
 103 static int dm_delay = 1;
 104 static unsigned long dm_hw_check_delta = 2*HZ;
 105 static LIST_HEAD(hw_stats_list);
 106
 107 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 108 static u32 net_dm_trunc_len;
 109 static u32 net_dm_queue_len = 1000;
 110
 111 struct net_dm_alert_ops {
 112         void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
 113                                 void *location,
 114                                 enum skb_drop_reason reason);
 115         void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 116                                 int work, int budget);
 117         void (*work_item_func)(struct work_struct *work);
 118         void (*hw_work_item_func)(struct work_struct *work);
 119         void (*hw_trap_probe)(void *ignore, const struct devlink *devlink,
 120                               struct sk_buff *skb,
 121                               const struct devlink_trap_metadata *metadata);
 122 };
 123
 124 struct net_dm_skb_cb {
 125         union {
 126                 struct devlink_trap_metadata *hw_metadata;
 127                 void *pc;
 128         };
 129 };
 130
 131 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
 132
 133 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 134 {
 135         size_t al;
 136         struct net_dm_alert_msg *msg;
 137         struct nlattr *nla;
 138         struct sk_buff *skb;
 139         unsigned long flags;
 140         void *msg_header;
 141
 142         al = sizeof(struct net_dm_alert_msg);
 143         al += dm_hit_limit * sizeof(struct net_dm_drop_point);
 144         al += sizeof(struct nlattr);
 145
 146         skb = genlmsg_new(al, GFP_KERNEL);
 147
 148         if (!skb)
 149                 goto err;
 150
 151         msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family,
 152                                  0, NET_DM_CMD_ALERT);
 153         if (!msg_header) {
 154                 nlmsg_free(skb);
 155                 skb = NULL;
 156                 goto err;
 157         }
 158         nla = nla_reserve(skb, NLA_UNSPEC,
 159                           sizeof(struct net_dm_alert_msg));
 160         if (!nla) {
 161                 nlmsg_free(skb);
 162                 skb = NULL;
 163                 goto err;
 164         }
 165         msg = nla_data(nla);
 166         memset(msg, 0, al);
 167         goto out;
 168
 169 err:
 170         mod_timer(&data->send_timer, jiffies + HZ / 10);
 171 out:
 172         spin_lock_irqsave(&data->lock, flags);
 173         swap(data->skb, skb);
 174         spin_unlock_irqrestore(&data->lock, flags);
 175
 176         if (skb) {
 177                 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
 178                 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh);
 179
 180                 genlmsg_end(skb, genlmsg_data(gnlh));
 181         }
 182
 183         return skb;
 184 }
 185
 186 static const struct genl_multicast_group dropmon_mcgrps[] = {
 187         { .name = "events", },
 188 };
 189
 190 static void send_dm_alert(struct work_struct *work)
 191 {
 192         struct sk_buff *skb;
 193         struct per_cpu_dm_data *data;
 194
 195         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 196
 197         skb = reset_per_cpu_data(data);
 198
 199         if (skb)
 200                 genlmsg_multicast(&net_drop_monitor_family, skb, 0,
 201                                   0, GFP_KERNEL);
 202 }
 203
 204 /*
 205  * This is the timer function to delay the sending of an alert
 206  * in the event that more drops will arrive during the
 207  * hysteresis period.
 208  */
 209 static void sched_send_work(struct timer_list *t)
 210 {
 211         struct per_cpu_dm_data *data = from_timer(data, t, send_timer);
 212
 213         schedule_work(&data->dm_alert_work);
 214 }
 215
 216 static void trace_drop_common(struct sk_buff *skb, void *location)
 217 {
 218         struct net_dm_alert_msg *msg;
 219         struct net_dm_drop_point *point;
 220         struct nlmsghdr *nlh;
 221         struct nlattr *nla;
 222         int i;
 223         struct sk_buff *dskb;
 224         struct per_cpu_dm_data *data;
 225         unsigned long flags;
 226
 227         local_irq_save(flags);
 228         data = this_cpu_ptr(&dm_cpu_data);
 229         spin_lock(&data->lock);
 230         dskb = data->skb;
 231
 232         if (!dskb)
 233                 goto out;
 234
 235         nlh = (struct nlmsghdr *)dskb->data;
 236         nla = genlmsg_data(nlmsg_data(nlh));
 237         msg = nla_data(nla);
 238         point = msg->points;
 239         for (i = 0; i < msg->entries; i++) {
 240                 if (!memcmp(&location, &point->pc, sizeof(void *))) {
 241                         point->count++;
 242                         goto out;
 243                 }
 244                 point++;
 245         }
 246         if (msg->entries == dm_hit_limit)
 247                 goto out;
 248         /*
 249          * We need to create a new entry
 250          */
 251         __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
 252         nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
 253         memcpy(point->pc, &location, sizeof(void *));
 254         point->count = 1;
 255         msg->entries++;
 256
 257         if (!timer_pending(&data->send_timer)) {
 258                 data->send_timer.expires = jiffies + dm_delay * HZ;
 259                 add_timer(&data->send_timer);
 260         }
 261
 262 out:
 263         spin_unlock_irqrestore(&data->lock, flags);
 264 }
 265
 266 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
 267                                 void *location,
 268                                 enum skb_drop_reason reason)
 269 {
 270         trace_drop_common(skb, location);
 271 }
 272
 273 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 274                                 int work, int budget)
 275 {
 276         struct dm_hw_stat_delta *new_stat;
 277
 278         /*
 279          * Don't check napi structures with no associated device
 280          */
 281         if (!napi->dev)
 282                 return;
 283
 284         rcu_read_lock();
 285         list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
 286                 struct net_device *dev;
 287
 288                 /*
 289                  * only add a note to our monitor buffer if:
 290                  * 1) this is the dev we received on
 291                  * 2) its after the last_rx delta
 292                  * 3) our rx_dropped count has gone up
 293                  */
 294                 /* Paired with WRITE_ONCE() in dropmon_net_event() */
 295                 dev = READ_ONCE(new_stat->dev);
 296                 if ((dev == napi->dev)  &&
 297                     (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) &&
 298                     (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
 299                         trace_drop_common(NULL, NULL);
 300                         new_stat->last_drop_val = napi->dev->stats.rx_dropped;
 301                         new_stat->last_rx = jiffies;
 302                         break;
 303                 }
 304         }
 305         rcu_read_unlock();
 306 }
 307
 308 static struct net_dm_hw_entries *
 309 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 310 {
 311         struct net_dm_hw_entries *hw_entries;
 312         unsigned long flags;
 313
 314         hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
 315                              GFP_KERNEL);
 316         if (!hw_entries) {
 317                 /* If the memory allocation failed, we try to perform another
 318                  * allocation in 1/10 second. Otherwise, the probe function
 319                  * will constantly bail out.
 320                  */
 321                 mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
 322         }
 323
 324         spin_lock_irqsave(&hw_data->lock, flags);
 325         swap(hw_data->hw_entries, hw_entries);
 326         spin_unlock_irqrestore(&hw_data->lock, flags);
 327
 328         return hw_entries;
 329 }
 330
 331 static int net_dm_hw_entry_put(struct sk_buff *msg,
 332                                const struct net_dm_hw_entry *hw_entry)
 333 {
 334         struct nlattr *attr;
 335
 336         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
 337         if (!attr)
 338                 return -EMSGSIZE;
 339
 340         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
 341                 goto nla_put_failure;
 342
 343         if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
 344                 goto nla_put_failure;
 345
 346         nla_nest_end(msg, attr);
 347
 348         return 0;
 349
 350 nla_put_failure:
 351         nla_nest_cancel(msg, attr);
 352         return -EMSGSIZE;
 353 }
 354
 355 static int net_dm_hw_entries_put(struct sk_buff *msg,
 356                                  const struct net_dm_hw_entries *hw_entries)
 357 {
 358         struct nlattr *attr;
 359         int i;
 360
 361         attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
 362         if (!attr)
 363                 return -EMSGSIZE;
 364
 365         for (i = 0; i < hw_entries->num_entries; i++) {
 366                 int rc;
 367
 368                 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
 369                 if (rc)
 370                         goto nla_put_failure;
 371         }
 372
 373         nla_nest_end(msg, attr);
 374
 375         return 0;
 376
 377 nla_put_failure:
 378         nla_nest_cancel(msg, attr);
 379         return -EMSGSIZE;
 380 }
 381
 382 static int
 383 net_dm_hw_summary_report_fill(struct sk_buff *msg,
 384                               const struct net_dm_hw_entries *hw_entries)
 385 {
 386         struct net_dm_alert_msg anc_hdr = { 0 };
 387         void *hdr;
 388         int rc;
 389
 390         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 391                           NET_DM_CMD_ALERT);
 392         if (!hdr)
 393                 return -EMSGSIZE;
 394
 395         /* We need to put the ancillary header in order not to break user
 396          * space.
 397          */
 398         if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
 399                 goto nla_put_failure;
 400
 401         rc = net_dm_hw_entries_put(msg, hw_entries);
 402         if (rc)
 403                 goto nla_put_failure;
 404
 405         genlmsg_end(msg, hdr);
 406
 407         return 0;
 408
 409 nla_put_failure:
 410         genlmsg_cancel(msg, hdr);
 411         return -EMSGSIZE;
 412 }
 413
 414 static void net_dm_hw_summary_work(struct work_struct *work)
 415 {
 416         struct net_dm_hw_entries *hw_entries;
 417         struct per_cpu_dm_data *hw_data;
 418         struct sk_buff *msg;
 419         int rc;
 420
 421         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 422
 423         hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
 424         if (!hw_entries)
 425                 return;
 426
 427         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 428         if (!msg)
 429                 goto out;
 430
 431         rc = net_dm_hw_summary_report_fill(msg, hw_entries);
 432         if (rc) {
 433                 nlmsg_free(msg);
 434                 goto out;
 435         }
 436
 437         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 438
 439 out:
 440         kfree(hw_entries);
 441 }
 442
 443 static void
 444 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink,
 445                              struct sk_buff *skb,
 446                              const struct devlink_trap_metadata *metadata)
 447 {
 448         struct net_dm_hw_entries *hw_entries;
 449         struct net_dm_hw_entry *hw_entry;
 450         struct per_cpu_dm_data *hw_data;
 451         unsigned long flags;
 452         int i;
 453
 454         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 455                 return;
 456
 457         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 458         spin_lock_irqsave(&hw_data->lock, flags);
 459         hw_entries = hw_data->hw_entries;
 460
 461         if (!hw_entries)
 462                 goto out;
 463
 464         for (i = 0; i < hw_entries->num_entries; i++) {
 465                 hw_entry = &hw_entries->entries[i];
 466                 if (!strncmp(hw_entry->trap_name, metadata->trap_name,
 467                              NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
 468                         hw_entry->count++;
 469                         goto out;
 470                 }
 471         }
 472         if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
 473                 goto out;
 474
 475         hw_entry = &hw_entries->entries[hw_entries->num_entries];
 476         strscpy(hw_entry->trap_name, metadata->trap_name,
 477                 NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
 478         hw_entry->count = 1;
 479         hw_entries->num_entries++;
 480
 481         if (!timer_pending(&hw_data->send_timer)) {
 482                 hw_data->send_timer.expires = jiffies + dm_delay * HZ;
 483                 add_timer(&hw_data->send_timer);
 484         }
 485
 486 out:
 487         spin_unlock_irqrestore(&hw_data->lock, flags);
 488 }
 489
 490 static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 491         .kfree_skb_probe        = trace_kfree_skb_hit,
 492         .napi_poll_probe        = trace_napi_poll_hit,
 493         .work_item_func         = send_dm_alert,
 494         .hw_work_item_func      = net_dm_hw_summary_work,
 495         .hw_trap_probe          = net_dm_hw_trap_summary_probe,
 496 };
 497
 498 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 499                                               struct sk_buff *skb,
 500                                               void *location,
 501                                               enum skb_drop_reason reason)
 502 {
 503         ktime_t tstamp = ktime_get_real();
 504         struct per_cpu_dm_data *data;
 505         struct sk_buff *nskb;
 506         unsigned long flags;
 507
 508         if (!skb_mac_header_was_set(skb))
 509                 return;
 510
 511         nskb = skb_clone(skb, GFP_ATOMIC);
 512         if (!nskb)
 513                 return;
 514
 515         NET_DM_SKB_CB(nskb)->pc = location;
 516         /* Override the timestamp because we care about the time when the
 517          * packet was dropped.
 518          */
 519         nskb->tstamp = tstamp;
 520
 521         data = this_cpu_ptr(&dm_cpu_data);
 522
 523         spin_lock_irqsave(&data->drop_queue.lock, flags);
 524         if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
 525                 __skb_queue_tail(&data->drop_queue, nskb);
 526         else
 527                 goto unlock_free;
 528         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 529
 530         schedule_work(&data->dm_alert_work);
 531
 532         return;
 533
 534 unlock_free:
 535         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 536         u64_stats_update_begin(&data->stats.syncp);
 537         data->stats.dropped++;
 538         u64_stats_update_end(&data->stats.syncp);
 539         consume_skb(nskb);
 540 }
 541
 542 static void net_dm_packet_trace_napi_poll_hit(void *ignore,
 543                                               struct napi_struct *napi,
 544                                               int work, int budget)
 545 {
 546 }
 547
 548 static size_t net_dm_in_port_size(void)
 549 {
 550                /* NET_DM_ATTR_IN_PORT nest */
 551         return nla_total_size(0) +
 552                /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
 553                nla_total_size(sizeof(u32)) +
 554                /* NET_DM_ATTR_PORT_NETDEV_NAME */
 555                nla_total_size(IFNAMSIZ + 1);
 556 }
 557
 558 #define NET_DM_MAX_SYMBOL_LEN 40
 559
 560 static size_t net_dm_packet_report_size(size_t payload_len)
 561 {
 562         size_t size;
 563
 564         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 565
 566         return NLMSG_ALIGN(size) +
 567                /* NET_DM_ATTR_ORIGIN */
 568                nla_total_size(sizeof(u16)) +
 569                /* NET_DM_ATTR_PC */
 570                nla_total_size(sizeof(u64)) +
 571                /* NET_DM_ATTR_SYMBOL */
 572                nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
 573                /* NET_DM_ATTR_IN_PORT */
 574                net_dm_in_port_size() +
 575                /* NET_DM_ATTR_TIMESTAMP */
 576                nla_total_size(sizeof(u64)) +
 577                /* NET_DM_ATTR_ORIG_LEN */
 578                nla_total_size(sizeof(u32)) +
 579                /* NET_DM_ATTR_PROTO */
 580                nla_total_size(sizeof(u16)) +
 581                /* NET_DM_ATTR_PAYLOAD */
 582                nla_total_size(payload_len);
 583 }
 584
 585 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
 586                                             const char *name)
 587 {
 588         struct nlattr *attr;
 589
 590         attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
 591         if (!attr)
 592                 return -EMSGSIZE;
 593
 594         if (ifindex &&
 595             nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
 596                 goto nla_put_failure;
 597
 598         if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
 599                 goto nla_put_failure;
 600
 601         nla_nest_end(msg, attr);
 602
 603         return 0;
 604
 605 nla_put_failure:
 606         nla_nest_cancel(msg, attr);
 607         return -EMSGSIZE;
 608 }
 609
 610 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
 611                                      size_t payload_len)
 612 {
 613         u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
 614         char buf[NET_DM_MAX_SYMBOL_LEN];
 615         struct nlattr *attr;
 616         void *hdr;
 617         int rc;
 618
 619         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 620                           NET_DM_CMD_PACKET_ALERT);
 621         if (!hdr)
 622                 return -EMSGSIZE;
 623
 624         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
 625                 goto nla_put_failure;
 626
 627         if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
 628                 goto nla_put_failure;
 629
 630         snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
 631         if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
 632                 goto nla_put_failure;
 633
 634         rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
 635         if (rc)
 636                 goto nla_put_failure;
 637
 638         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 639                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 640                 goto nla_put_failure;
 641
 642         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 643                 goto nla_put_failure;
 644
 645         if (!payload_len)
 646                 goto out;
 647
 648         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 649                 goto nla_put_failure;
 650
 651         attr = skb_put(msg, nla_total_size(payload_len));
 652         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 653         attr->nla_len = nla_attr_size(payload_len);
 654         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 655                 goto nla_put_failure;
 656
 657 out:
 658         genlmsg_end(msg, hdr);
 659
 660         return 0;
 661
 662 nla_put_failure:
 663         genlmsg_cancel(msg, hdr);
 664         return -EMSGSIZE;
 665 }
 666
 667 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
 668
 669 static void net_dm_packet_report(struct sk_buff *skb)
 670 {
 671         struct sk_buff *msg;
 672         size_t payload_len;
 673         int rc;
 674
 675         /* Make sure we start copying the packet from the MAC header */
 676         if (skb->data > skb_mac_header(skb))
 677                 skb_push(skb, skb->data - skb_mac_header(skb));
 678         else
 679                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 680
 681         /* Ensure packet fits inside a single netlink attribute */
 682         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 683         if (net_dm_trunc_len)
 684                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 685
 686         msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
 687         if (!msg)
 688                 goto out;
 689
 690         rc = net_dm_packet_report_fill(msg, skb, payload_len);
 691         if (rc) {
 692                 nlmsg_free(msg);
 693                 goto out;
 694         }
 695
 696         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 697
 698 out:
 699         consume_skb(skb);
 700 }
 701
 702 static void net_dm_packet_work(struct work_struct *work)
 703 {
 704         struct per_cpu_dm_data *data;
 705         struct sk_buff_head list;
 706         struct sk_buff *skb;
 707         unsigned long flags;
 708
 709         data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 710
 711         __skb_queue_head_init(&list);
 712
 713         spin_lock_irqsave(&data->drop_queue.lock, flags);
 714         skb_queue_splice_tail_init(&data->drop_queue, &list);
 715         spin_unlock_irqrestore(&data->drop_queue.lock, flags);
 716
 717         while ((skb = __skb_dequeue(&list)))
 718                 net_dm_packet_report(skb);
 719 }
 720
 721 static size_t
 722 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata)
 723 {
 724         return hw_metadata->fa_cookie ?
 725                nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0;
 726 }
 727
 728 static size_t
 729 net_dm_hw_packet_report_size(size_t payload_len,
 730                              const struct devlink_trap_metadata *hw_metadata)
 731 {
 732         size_t size;
 733
 734         size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
 735
 736         return NLMSG_ALIGN(size) +
 737                /* NET_DM_ATTR_ORIGIN */
 738                nla_total_size(sizeof(u16)) +
 739                /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
 740                nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
 741                /* NET_DM_ATTR_HW_TRAP_NAME */
 742                nla_total_size(strlen(hw_metadata->trap_name) + 1) +
 743                /* NET_DM_ATTR_IN_PORT */
 744                net_dm_in_port_size() +
 745                /* NET_DM_ATTR_FLOW_ACTION_COOKIE */
 746                net_dm_flow_action_cookie_size(hw_metadata) +
 747                /* NET_DM_ATTR_TIMESTAMP */
 748                nla_total_size(sizeof(u64)) +
 749                /* NET_DM_ATTR_ORIG_LEN */
 750                nla_total_size(sizeof(u32)) +
 751                /* NET_DM_ATTR_PROTO */
 752                nla_total_size(sizeof(u16)) +
 753                /* NET_DM_ATTR_PAYLOAD */
 754                nla_total_size(payload_len);
 755 }
 756
 757 static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
 758                                         struct sk_buff *skb, size_t payload_len)
 759 {
 760         struct devlink_trap_metadata *hw_metadata;
 761         struct nlattr *attr;
 762         void *hdr;
 763
 764         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 765
 766         hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
 767                           NET_DM_CMD_PACKET_ALERT);
 768         if (!hdr)
 769                 return -EMSGSIZE;
 770
 771         if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
 772                 goto nla_put_failure;
 773
 774         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
 775                            hw_metadata->trap_group_name))
 776                 goto nla_put_failure;
 777
 778         if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
 779                            hw_metadata->trap_name))
 780                 goto nla_put_failure;
 781
 782         if (hw_metadata->input_dev) {
 783                 struct net_device *dev = hw_metadata->input_dev;
 784                 int rc;
 785
 786                 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
 787                                                       dev->name);
 788                 if (rc)
 789                         goto nla_put_failure;
 790         }
 791
 792         if (hw_metadata->fa_cookie &&
 793             nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE,
 794                     hw_metadata->fa_cookie->cookie_len,
 795                     hw_metadata->fa_cookie->cookie))
 796                 goto nla_put_failure;
 797
 798         if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
 799                               ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
 800                 goto nla_put_failure;
 801
 802         if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
 803                 goto nla_put_failure;
 804
 805         if (!payload_len)
 806                 goto out;
 807
 808         if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
 809                 goto nla_put_failure;
 810
 811         attr = skb_put(msg, nla_total_size(payload_len));
 812         attr->nla_type = NET_DM_ATTR_PAYLOAD;
 813         attr->nla_len = nla_attr_size(payload_len);
 814         if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
 815                 goto nla_put_failure;
 816
 817 out:
 818         genlmsg_end(msg, hdr);
 819
 820         return 0;
 821
 822 nla_put_failure:
 823         genlmsg_cancel(msg, hdr);
 824         return -EMSGSIZE;
 825 }
 826
 827 static struct devlink_trap_metadata *
 828 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata)
 829 {
 830         const struct flow_action_cookie *fa_cookie;
 831         struct devlink_trap_metadata *hw_metadata;
 832         const char *trap_group_name;
 833         const char *trap_name;
 834
 835         hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC);
 836         if (!hw_metadata)
 837                 return NULL;
 838
 839         trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC);
 840         if (!trap_group_name)
 841                 goto free_hw_metadata;
 842         hw_metadata->trap_group_name = trap_group_name;
 843
 844         trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC);
 845         if (!trap_name)
 846                 goto free_trap_group;
 847         hw_metadata->trap_name = trap_name;
 848
 849         if (metadata->fa_cookie) {
 850                 size_t cookie_size = sizeof(*fa_cookie) +
 851                                      metadata->fa_cookie->cookie_len;
 852
 853                 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size,
 854                                     GFP_ATOMIC);
 855                 if (!fa_cookie)
 856                         goto free_trap_name;
 857                 hw_metadata->fa_cookie = fa_cookie;
 858         }
 859
 860         hw_metadata->input_dev = metadata->input_dev;
 861         dev_hold(hw_metadata->input_dev);
 862
 863         return hw_metadata;
 864
 865 free_trap_name:
 866         kfree(trap_name);
 867 free_trap_group:
 868         kfree(trap_group_name);
 869 free_hw_metadata:
 870         kfree(hw_metadata);
 871         return NULL;
 872 }
 873
 874 static void
 875 net_dm_hw_metadata_free(const struct devlink_trap_metadata *hw_metadata)
 876 {
 877         dev_put(hw_metadata->input_dev);
 878         kfree(hw_metadata->fa_cookie);
 879         kfree(hw_metadata->trap_name);
 880         kfree(hw_metadata->trap_group_name);
 881         kfree(hw_metadata);
 882 }
 883
 884 static void net_dm_hw_packet_report(struct sk_buff *skb)
 885 {
 886         struct devlink_trap_metadata *hw_metadata;
 887         struct sk_buff *msg;
 888         size_t payload_len;
 889         int rc;
 890
 891         if (skb->data > skb_mac_header(skb))
 892                 skb_push(skb, skb->data - skb_mac_header(skb));
 893         else
 894                 skb_pull(skb, skb_mac_header(skb) - skb->data);
 895
 896         payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
 897         if (net_dm_trunc_len)
 898                 payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
 899
 900         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
 901         msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
 902                         GFP_KERNEL);
 903         if (!msg)
 904                 goto out;
 905
 906         rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
 907         if (rc) {
 908                 nlmsg_free(msg);
 909                 goto out;
 910         }
 911
 912         genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
 913
 914 out:
 915         net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 916         consume_skb(skb);
 917 }
 918
 919 static void net_dm_hw_packet_work(struct work_struct *work)
 920 {
 921         struct per_cpu_dm_data *hw_data;
 922         struct sk_buff_head list;
 923         struct sk_buff *skb;
 924         unsigned long flags;
 925
 926         hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
 927
 928         __skb_queue_head_init(&list);
 929
 930         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 931         skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
 932         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 933
 934         while ((skb = __skb_dequeue(&list)))
 935                 net_dm_hw_packet_report(skb);
 936 }
 937
 938 static void
 939 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink,
 940                             struct sk_buff *skb,
 941                             const struct devlink_trap_metadata *metadata)
 942 {
 943         struct devlink_trap_metadata *n_hw_metadata;
 944         ktime_t tstamp = ktime_get_real();
 945         struct per_cpu_dm_data *hw_data;
 946         struct sk_buff *nskb;
 947         unsigned long flags;
 948
 949         if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL)
 950                 return;
 951
 952         if (!skb_mac_header_was_set(skb))
 953                 return;
 954
 955         nskb = skb_clone(skb, GFP_ATOMIC);
 956         if (!nskb)
 957                 return;
 958
 959         n_hw_metadata = net_dm_hw_metadata_copy(metadata);
 960         if (!n_hw_metadata)
 961                 goto free;
 962
 963         NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
 964         nskb->tstamp = tstamp;
 965
 966         hw_data = this_cpu_ptr(&dm_hw_cpu_data);
 967
 968         spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
 969         if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
 970                 __skb_queue_tail(&hw_data->drop_queue, nskb);
 971         else
 972                 goto unlock_free;
 973         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 974
 975         schedule_work(&hw_data->dm_alert_work);
 976
 977         return;
 978
 979 unlock_free:
 980         spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
 981         u64_stats_update_begin(&hw_data->stats.syncp);
 982         hw_data->stats.dropped++;
 983         u64_stats_update_end(&hw_data->stats.syncp);
 984         net_dm_hw_metadata_free(n_hw_metadata);
 985 free:
 986         consume_skb(nskb);
 987 }
 988
 989 static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
 990         .kfree_skb_probe        = net_dm_packet_trace_kfree_skb_hit,
 991         .napi_poll_probe        = net_dm_packet_trace_napi_poll_hit,
 992         .work_item_func         = net_dm_packet_work,
 993         .hw_work_item_func      = net_dm_hw_packet_work,
 994         .hw_trap_probe          = net_dm_hw_trap_packet_probe,
 995 };
 996
 997 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
 998         [NET_DM_ALERT_MODE_SUMMARY]     = &net_dm_alert_summary_ops,
 999         [NET_DM_ALERT_MODE_PACKET]      = &net_dm_alert_packet_ops,
1000 };
1001
1002 #if IS_ENABLED(CONFIG_NET_DEVLINK)
1003 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1004 {
1005         return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1006 }
1007
1008 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1009 {
1010         unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL);
1011         tracepoint_synchronize_unregister();
1012 }
1013 #else
1014 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1015 {
1016         return -EOPNOTSUPP;
1017 }
1018
1019 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1020 {
1021 }
1022 #endif
1023
1024 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
1025 {
1026         const struct net_dm_alert_ops *ops;
1027         int cpu, rc;
1028
1029         if (monitor_hw) {
1030                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
1031                 return -EAGAIN;
1032         }
1033
1034         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1035
1036         if (!try_module_get(THIS_MODULE)) {
1037                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1038                 return -ENODEV;
1039         }
1040
1041         for_each_possible_cpu(cpu) {
1042                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1043                 struct net_dm_hw_entries *hw_entries;
1044
1045                 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
1046                 timer_setup(&hw_data->send_timer, sched_send_work, 0);
1047                 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
1048                 kfree(hw_entries);
1049         }
1050
1051         rc = net_dm_hw_probe_register(ops);
1052         if (rc) {
1053                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint");
1054                 goto err_module_put;
1055         }
1056
1057         monitor_hw = true;
1058
1059         return 0;
1060
1061 err_module_put:
1062         for_each_possible_cpu(cpu) {
1063                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1064                 struct sk_buff *skb;
1065
1066                 del_timer_sync(&hw_data->send_timer);
1067                 cancel_work_sync(&hw_data->dm_alert_work);
1068                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1069                         struct devlink_trap_metadata *hw_metadata;
1070
1071                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1072                         net_dm_hw_metadata_free(hw_metadata);
1073                         consume_skb(skb);
1074                 }
1075         }
1076         module_put(THIS_MODULE);
1077         return rc;
1078 }
1079
1080 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
1081 {
1082         const struct net_dm_alert_ops *ops;
1083         int cpu;
1084
1085         if (!monitor_hw) {
1086                 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
1087                 return;
1088         }
1089
1090         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1091
1092         monitor_hw = false;
1093
1094         net_dm_hw_probe_unregister(ops);
1095
1096         for_each_possible_cpu(cpu) {
1097                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1098                 struct sk_buff *skb;
1099
1100                 del_timer_sync(&hw_data->send_timer);
1101                 cancel_work_sync(&hw_data->dm_alert_work);
1102                 while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
1103                         struct devlink_trap_metadata *hw_metadata;
1104
1105                         hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
1106                         net_dm_hw_metadata_free(hw_metadata);
1107                         consume_skb(skb);
1108                 }
1109         }
1110
1111         module_put(THIS_MODULE);
1112 }
1113
1114 static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
1115 {
1116         const struct net_dm_alert_ops *ops;
1117         int cpu, rc;
1118
1119         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1120
1121         if (!try_module_get(THIS_MODULE)) {
1122                 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
1123                 return -ENODEV;
1124         }
1125
1126         for_each_possible_cpu(cpu) {
1127                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1128                 struct sk_buff *skb;
1129
1130                 INIT_WORK(&data->dm_alert_work, ops->work_item_func);
1131                 timer_setup(&data->send_timer, sched_send_work, 0);
1132                 /* Allocate a new per-CPU skb for the summary alert message and
1133                  * free the old one which might contain stale data from
1134                  * previous tracing.
1135                  */
1136                 skb = reset_per_cpu_data(data);
1137                 consume_skb(skb);
1138         }
1139
1140         rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1141         if (rc) {
1142                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
1143                 goto err_module_put;
1144         }
1145
1146         rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
1147         if (rc) {
1148                 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
1149                 goto err_unregister_trace;
1150         }
1151
1152         return 0;
1153
1154 err_unregister_trace:
1155         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1156 err_module_put:
1157         for_each_possible_cpu(cpu) {
1158                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1159                 struct sk_buff *skb;
1160
1161                 del_timer_sync(&data->send_timer);
1162                 cancel_work_sync(&data->dm_alert_work);
1163                 while ((skb = __skb_dequeue(&data->drop_queue)))
1164                         consume_skb(skb);
1165         }
1166         module_put(THIS_MODULE);
1167         return rc;
1168 }
1169
1170 static void net_dm_trace_off_set(void)
1171 {
1172         struct dm_hw_stat_delta *new_stat, *temp;
1173         const struct net_dm_alert_ops *ops;
1174         int cpu;
1175
1176         ops = net_dm_alert_ops_arr[net_dm_alert_mode];
1177
1178         unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
1179         unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1180
1181         tracepoint_synchronize_unregister();
1182
1183         /* Make sure we do not send notifications to user space after request
1184          * to stop tracing returns.
1185          */
1186         for_each_possible_cpu(cpu) {
1187                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1188                 struct sk_buff *skb;
1189
1190                 del_timer_sync(&data->send_timer);
1191                 cancel_work_sync(&data->dm_alert_work);
1192                 while ((skb = __skb_dequeue(&data->drop_queue)))
1193                         consume_skb(skb);
1194         }
1195
1196         list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
1197                 if (new_stat->dev == NULL) {
1198                         list_del_rcu(&new_stat->list);
1199                         kfree_rcu(new_stat, rcu);
1200                 }
1201         }
1202
1203         module_put(THIS_MODULE);
1204 }
1205
1206 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
1207 {
1208         int rc = 0;
1209
1210         if (state == trace_state) {
1211                 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
1212                 return -EAGAIN;
1213         }
1214
1215         switch (state) {
1216         case TRACE_ON:
1217                 rc = net_dm_trace_on_set(extack);
1218                 break;
1219         case TRACE_OFF:
1220                 net_dm_trace_off_set();
1221                 break;
1222         default:
1223                 rc = 1;
1224                 break;
1225         }
1226
1227         if (!rc)
1228                 trace_state = state;
1229         else
1230                 rc = -EINPROGRESS;
1231
1232         return rc;
1233 }
1234
1235 static bool net_dm_is_monitoring(void)
1236 {
1237         return trace_state == TRACE_ON || monitor_hw;
1238 }
1239
1240 static int net_dm_alert_mode_get_from_info(struct genl_info *info,
1241                                            enum net_dm_alert_mode *p_alert_mode)
1242 {
1243         u8 val;
1244
1245         val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
1246
1247         switch (val) {
1248         case NET_DM_ALERT_MODE_SUMMARY:
1249         case NET_DM_ALERT_MODE_PACKET:
1250                 *p_alert_mode = val;
1251                 break;
1252         default:
1253                 return -EINVAL;
1254         }
1255
1256         return 0;
1257 }
1258
1259 static int net_dm_alert_mode_set(struct genl_info *info)
1260 {
1261         struct netlink_ext_ack *extack = info->extack;
1262         enum net_dm_alert_mode alert_mode;
1263         int rc;
1264
1265         if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
1266                 return 0;
1267
1268         rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
1269         if (rc) {
1270                 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
1271                 return -EINVAL;
1272         }
1273
1274         net_dm_alert_mode = alert_mode;
1275
1276         return 0;
1277 }
1278
1279 static void net_dm_trunc_len_set(struct genl_info *info)
1280 {
1281         if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
1282                 return;
1283
1284         net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
1285 }
1286
1287 static void net_dm_queue_len_set(struct genl_info *info)
1288 {
1289         if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
1290                 return;
1291
1292         net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
1293 }
1294
1295 static int net_dm_cmd_config(struct sk_buff *skb,
1296                         struct genl_info *info)
1297 {
1298         struct netlink_ext_ack *extack = info->extack;
1299         int rc;
1300
1301         if (net_dm_is_monitoring()) {
1302                 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
1303                 return -EBUSY;
1304         }
1305
1306         rc = net_dm_alert_mode_set(info);
1307         if (rc)
1308                 return rc;
1309
1310         net_dm_trunc_len_set(info);
1311
1312         net_dm_queue_len_set(info);
1313
1314         return 0;
1315 }
1316
1317 static int net_dm_monitor_start(bool set_sw, bool set_hw,
1318                                 struct netlink_ext_ack *extack)
1319 {
1320         bool sw_set = false;
1321         int rc;
1322
1323         if (set_sw) {
1324                 rc = set_all_monitor_traces(TRACE_ON, extack);
1325                 if (rc)
1326                         return rc;
1327                 sw_set = true;
1328         }
1329
1330         if (set_hw) {
1331                 rc = net_dm_hw_monitor_start(extack);
1332                 if (rc)
1333                         goto err_monitor_hw;
1334         }
1335
1336         return 0;
1337
1338 err_monitor_hw:
1339         if (sw_set)
1340                 set_all_monitor_traces(TRACE_OFF, extack);
1341         return rc;
1342 }
1343
1344 static void net_dm_monitor_stop(bool set_sw, bool set_hw,
1345                                 struct netlink_ext_ack *extack)
1346 {
1347         if (set_hw)
1348                 net_dm_hw_monitor_stop(extack);
1349         if (set_sw)
1350                 set_all_monitor_traces(TRACE_OFF, extack);
1351 }
1352
1353 static int net_dm_cmd_trace(struct sk_buff *skb,
1354                         struct genl_info *info)
1355 {
1356         bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
1357         bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
1358         struct netlink_ext_ack *extack = info->extack;
1359
1360         /* To maintain backward compatibility, we start / stop monitoring of
1361          * software drops if no flag is specified.
1362          */
1363         if (!set_sw && !set_hw)
1364                 set_sw = true;
1365
1366         switch (info->genlhdr->cmd) {
1367         case NET_DM_CMD_START:
1368                 return net_dm_monitor_start(set_sw, set_hw, extack);
1369         case NET_DM_CMD_STOP:
1370                 net_dm_monitor_stop(set_sw, set_hw, extack);
1371                 return 0;
1372         }
1373
1374         return -EOPNOTSUPP;
1375 }
1376
1377 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
1378 {
1379         void *hdr;
1380
1381         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1382                           &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
1383         if (!hdr)
1384                 return -EMSGSIZE;
1385
1386         if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
1387                 goto nla_put_failure;
1388
1389         if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
1390                 goto nla_put_failure;
1391
1392         if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
1393                 goto nla_put_failure;
1394
1395         genlmsg_end(msg, hdr);
1396
1397         return 0;
1398
1399 nla_put_failure:
1400         genlmsg_cancel(msg, hdr);
1401         return -EMSGSIZE;
1402 }
1403
1404 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
1405 {
1406         struct sk_buff *msg;
1407         int rc;
1408
1409         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1410         if (!msg)
1411                 return -ENOMEM;
1412
1413         rc = net_dm_config_fill(msg, info);
1414         if (rc)
1415                 goto free_msg;
1416
1417         return genlmsg_reply(msg, info);
1418
1419 free_msg:
1420         nlmsg_free(msg);
1421         return rc;
1422 }
1423
1424 static void net_dm_stats_read(struct net_dm_stats *stats)
1425 {
1426         int cpu;
1427
1428         memset(stats, 0, sizeof(*stats));
1429         for_each_possible_cpu(cpu) {
1430                 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
1431                 struct net_dm_stats *cpu_stats = &data->stats;
1432                 unsigned int start;
1433                 u64 dropped;
1434
1435                 do {
1436                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1437                         dropped = cpu_stats->dropped;
1438                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1439
1440                 stats->dropped += dropped;
1441         }
1442 }
1443
1444 static int net_dm_stats_put(struct sk_buff *msg)
1445 {
1446         struct net_dm_stats stats;
1447         struct nlattr *attr;
1448
1449         net_dm_stats_read(&stats);
1450
1451         attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
1452         if (!attr)
1453                 return -EMSGSIZE;
1454
1455         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1456                               stats.dropped, NET_DM_ATTR_PAD))
1457                 goto nla_put_failure;
1458
1459         nla_nest_end(msg, attr);
1460
1461         return 0;
1462
1463 nla_put_failure:
1464         nla_nest_cancel(msg, attr);
1465         return -EMSGSIZE;
1466 }
1467
1468 static void net_dm_hw_stats_read(struct net_dm_stats *stats)
1469 {
1470         int cpu;
1471
1472         memset(stats, 0, sizeof(*stats));
1473         for_each_possible_cpu(cpu) {
1474                 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1475                 struct net_dm_stats *cpu_stats = &hw_data->stats;
1476                 unsigned int start;
1477                 u64 dropped;
1478
1479                 do {
1480                         start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
1481                         dropped = cpu_stats->dropped;
1482                 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
1483
1484                 stats->dropped += dropped;
1485         }
1486 }
1487
1488 static int net_dm_hw_stats_put(struct sk_buff *msg)
1489 {
1490         struct net_dm_stats stats;
1491         struct nlattr *attr;
1492
1493         net_dm_hw_stats_read(&stats);
1494
1495         attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
1496         if (!attr)
1497                 return -EMSGSIZE;
1498
1499         if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
1500                               stats.dropped, NET_DM_ATTR_PAD))
1501                 goto nla_put_failure;
1502
1503         nla_nest_end(msg, attr);
1504
1505         return 0;
1506
1507 nla_put_failure:
1508         nla_nest_cancel(msg, attr);
1509         return -EMSGSIZE;
1510 }
1511
1512 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
1513 {
1514         void *hdr;
1515         int rc;
1516
1517         hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
1518                           &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
1519         if (!hdr)
1520                 return -EMSGSIZE;
1521
1522         rc = net_dm_stats_put(msg);
1523         if (rc)
1524                 goto nla_put_failure;
1525
1526         rc = net_dm_hw_stats_put(msg);
1527         if (rc)
1528                 goto nla_put_failure;
1529
1530         genlmsg_end(msg, hdr);
1531
1532         return 0;
1533
1534 nla_put_failure:
1535         genlmsg_cancel(msg, hdr);
1536         return -EMSGSIZE;
1537 }
1538
1539 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
1540 {
1541         struct sk_buff *msg;
1542         int rc;
1543
1544         msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
1545         if (!msg)
1546                 return -ENOMEM;
1547
1548         rc = net_dm_stats_fill(msg, info);
1549         if (rc)
1550                 goto free_msg;
1551
1552         return genlmsg_reply(msg, info);
1553
1554 free_msg:
1555         nlmsg_free(msg);
1556         return rc;
1557 }
1558
1559 static int dropmon_net_event(struct notifier_block *ev_block,
1560                              unsigned long event, void *ptr)
1561 {
1562         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1563         struct dm_hw_stat_delta *new_stat = NULL;
1564         struct dm_hw_stat_delta *tmp;
1565
1566         switch (event) {
1567         case NETDEV_REGISTER:
1568                 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
1569
1570                 if (!new_stat)
1571                         goto out;
1572
1573                 new_stat->dev = dev;
1574                 new_stat->last_rx = jiffies;
1575                 mutex_lock(&net_dm_mutex);
1576                 list_add_rcu(&new_stat->list, &hw_stats_list);
1577                 mutex_unlock(&net_dm_mutex);
1578                 break;
1579         case NETDEV_UNREGISTER:
1580                 mutex_lock(&net_dm_mutex);
1581                 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
1582                         if (new_stat->dev == dev) {
1583
1584                                 /* Paired with READ_ONCE() in trace_napi_poll_hit() */
1585                                 WRITE_ONCE(new_stat->dev, NULL);
1586
1587                                 if (trace_state == TRACE_OFF) {
1588                                         list_del_rcu(&new_stat->list);
1589                                         kfree_rcu(new_stat, rcu);
1590                                         break;
1591                                 }
1592                         }
1593                 }
1594                 mutex_unlock(&net_dm_mutex);
1595                 break;
1596         }
1597 out:
1598         return NOTIFY_DONE;
1599 }
1600
1601 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
1602         [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
1603         [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
1604         [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
1605         [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
1606         [NET_DM_ATTR_SW_DROPS]  = {. type = NLA_FLAG },
1607         [NET_DM_ATTR_HW_DROPS]  = {. type = NLA_FLAG },
1608 };
1609
1610 static const struct genl_small_ops dropmon_ops[] = {
1611         {
1612                 .cmd = NET_DM_CMD_CONFIG,
1613                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1614                 .doit = net_dm_cmd_config,
1615                 .flags = GENL_ADMIN_PERM,
1616         },
1617         {
1618                 .cmd = NET_DM_CMD_START,
1619                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1620                 .doit = net_dm_cmd_trace,
1621         },
1622         {
1623                 .cmd = NET_DM_CMD_STOP,
1624                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1625                 .doit = net_dm_cmd_trace,
1626         },
1627         {
1628                 .cmd = NET_DM_CMD_CONFIG_GET,
1629                 .doit = net_dm_cmd_config_get,
1630         },
1631         {
1632                 .cmd = NET_DM_CMD_STATS_GET,
1633                 .doit = net_dm_cmd_stats_get,
1634         },
1635 };
1636
1637 static int net_dm_nl_pre_doit(const struct genl_ops *ops,
1638                               struct sk_buff *skb, struct genl_info *info)
1639 {
1640         mutex_lock(&net_dm_mutex);
1641
1642         return 0;
1643 }
1644
1645 static void net_dm_nl_post_doit(const struct genl_ops *ops,
1646                                 struct sk_buff *skb, struct genl_info *info)
1647 {
1648         mutex_unlock(&net_dm_mutex);
1649 }
1650
1651 static struct genl_family net_drop_monitor_family __ro_after_init = {
1652         .hdrsize        = 0,
1653         .name           = "NET_DM",
1654         .version        = 2,
1655         .maxattr        = NET_DM_ATTR_MAX,
1656         .policy         = net_dm_nl_policy,
1657         .pre_doit       = net_dm_nl_pre_doit,
1658         .post_doit      = net_dm_nl_post_doit,
1659         .module         = THIS_MODULE,
1660         .small_ops      = dropmon_ops,
1661         .n_small_ops    = ARRAY_SIZE(dropmon_ops),
1662         .mcgrps         = dropmon_mcgrps,
1663         .n_mcgrps       = ARRAY_SIZE(dropmon_mcgrps),
1664 };
1665
1666 static struct notifier_block dropmon_net_notifier = {
1667         .notifier_call = dropmon_net_event
1668 };
1669
1670 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
1671 {
1672         spin_lock_init(&data->lock);
1673         skb_queue_head_init(&data->drop_queue);
1674         u64_stats_init(&data->stats.syncp);
1675 }
1676
1677 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1678 {
1679         WARN_ON(!skb_queue_empty(&data->drop_queue));
1680 }
1681
1682 static void net_dm_cpu_data_init(int cpu)
1683 {
1684         struct per_cpu_dm_data *data;
1685
1686         data = &per_cpu(dm_cpu_data, cpu);
1687         __net_dm_cpu_data_init(data);
1688 }
1689
1690 static void net_dm_cpu_data_fini(int cpu)
1691 {
1692         struct per_cpu_dm_data *data;
1693
1694         data = &per_cpu(dm_cpu_data, cpu);
1695         /* At this point, we should have exclusive access
1696          * to this struct and can free the skb inside it.
1697          */
1698         consume_skb(data->skb);
1699         __net_dm_cpu_data_fini(data);
1700 }
1701
1702 static void net_dm_hw_cpu_data_init(int cpu)
1703 {
1704         struct per_cpu_dm_data *hw_data;
1705
1706         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1707         __net_dm_cpu_data_init(hw_data);
1708 }
1709
1710 static void net_dm_hw_cpu_data_fini(int cpu)
1711 {
1712         struct per_cpu_dm_data *hw_data;
1713
1714         hw_data = &per_cpu(dm_hw_cpu_data, cpu);
1715         kfree(hw_data->hw_entries);
1716         __net_dm_cpu_data_fini(hw_data);
1717 }
1718
1719 static int __init init_net_drop_monitor(void)
1720 {
1721         int cpu, rc;
1722
1723         pr_info("Initializing network drop monitor service\n");
1724
1725         if (sizeof(void *) > 8) {
1726                 pr_err("Unable to store program counters on this arch, Drop monitor failed\n");
1727                 return -ENOSPC;
1728         }
1729
1730         rc = genl_register_family(&net_drop_monitor_family);
1731         if (rc) {
1732                 pr_err("Could not create drop monitor netlink family\n");
1733                 return rc;
1734         }
1735         WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1736
1737         rc = register_netdevice_notifier(&dropmon_net_notifier);
1738         if (rc < 0) {
1739                 pr_crit("Failed to register netdevice notifier\n");
1740                 goto out_unreg;
1741         }
1742
1743         rc = 0;
1744
1745         for_each_possible_cpu(cpu) {
1746                 net_dm_cpu_data_init(cpu);
1747                 net_dm_hw_cpu_data_init(cpu);
1748         }
1749
1750         goto out;
1751
1752 out_unreg:
1753         genl_unregister_family(&net_drop_monitor_family);
1754 out:
1755         return rc;
1756 }
1757
1758 static void exit_net_drop_monitor(void)
1759 {
1760         int cpu;
1761
1762         BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1763
1764         /*
1765          * Because of the module_get/put we do in the trace state change path
1766          * we are guaranteed not to have any current users when we get here
1767          */
1768
1769         for_each_possible_cpu(cpu) {
1770                 net_dm_hw_cpu_data_fini(cpu);
1771                 net_dm_cpu_data_fini(cpu);
1772         }
1773
1774         BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1775 }
1776
1777 module_init(init_net_drop_monitor);
1778 module_exit(exit_net_drop_monitor);
1779
1780 MODULE_LICENSE("GPL v2");
1781 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1782 MODULE_ALIAS_GENL_FAMILY("NET_DM");
1783 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");