net/core/drop_monitor.c

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