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