net/core/drop_monitor.c

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