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/bitfield.h> 25 #include <linux/percpu.h> 26 #include <linux/timer.h> 27 #include <linux/bitops.h> 28 #include <linux/slab.h> 29 #include <linux/module.h> 30 #include <net/genetlink.h> 31 #include <net/netevent.h> 32 #include <net/flow_offload.h> 33 #include <net/dropreason.h> 34 #include <net/devlink.h> 35 36 #include <trace/events/skb.h> 37 #include <trace/events/napi.h> 38 #include <trace/events/devlink.h> 39 40 #include <linux/unaligned.h> 41 42 #define TRACE_ON 1 43 #define TRACE_OFF 0 44 45 /* 46 * Globals, our netlink socket pointer 47 * and the work handle that will send up 48 * netlink alerts 49 */ 50 static int trace_state = TRACE_OFF; 51 static bool monitor_hw; 52 53 /* net_dm_mutex 54 * 55 * An overall lock guarding every operation coming from userspace. 56 */ 57 static DEFINE_MUTEX(net_dm_mutex); 58 59 struct net_dm_stats { 60 u64_stats_t dropped; 61 struct u64_stats_sync syncp; 62 }; 63 64 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40 65 66 struct net_dm_hw_entry { 67 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN]; 68 u32 count; 69 }; 70 71 struct net_dm_hw_entries { 72 u32 num_entries; 73 struct net_dm_hw_entry entries[]; 74 }; 75 76 struct per_cpu_dm_data { 77 raw_spinlock_t lock; /* Protects 'skb', 'hw_entries' and 78 * 'send_timer' 79 */ 80 union { 81 struct sk_buff *skb; 82 struct net_dm_hw_entries *hw_entries; 83 }; 84 struct sk_buff_head drop_queue; 85 struct work_struct dm_alert_work; 86 struct timer_list send_timer; 87 struct net_dm_stats stats; 88 }; 89 90 struct dm_hw_stat_delta { 91 unsigned long last_rx; 92 unsigned long last_drop_val; 93 struct rcu_head rcu; 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; 104 105 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY; 106 static u32 net_dm_trunc_len; 107 static u32 net_dm_queue_len = 1000; 108 109 struct net_dm_alert_ops { 110 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, 111 void *location, 112 enum skb_drop_reason reason, 113 const struct sock *rx_sk); 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 enum skb_drop_reason reason; 129 }; 130 131 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) 132 133 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) 134 { 135 size_t al; 136 struct net_dm_alert_msg *msg; 137 struct nlattr *nla; 138 struct sk_buff *skb; 139 unsigned long flags; 140 void *msg_header; 141 142 al = sizeof(struct net_dm_alert_msg); 143 al += dm_hit_limit * sizeof(struct net_dm_drop_point); 144 145 skb = genlmsg_new(nla_total_size(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 raw_spin_lock_irqsave(&data->lock, flags); 172 swap(data->skb, skb); 173 raw_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", .flags = GENL_MCAST_CAP_SYS_ADMIN, }, 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 = timer_container_of(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 raw_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 raw_spin_unlock_irqrestore(&data->lock, flags); 263 } 264 265 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, 266 void *location, 267 enum skb_drop_reason reason, 268 const struct sock *rx_sk) 269 { 270 trace_drop_common(skb, location); 271 } 272 273 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, 274 int work, int budget) 275 { 276 struct net_device *dev = napi->dev; 277 struct dm_hw_stat_delta *stat; 278 /* 279 * Don't check napi structures with no associated device 280 */ 281 if (!dev) 282 return; 283 284 rcu_read_lock(); 285 stat = rcu_dereference(dev->dm_private); 286 if (stat) { 287 /* 288 * only add a note to our monitor buffer if: 289 * 1) its after the last_rx delta 290 * 2) our rx_dropped count has gone up 291 */ 292 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) && 293 (dev->stats.rx_dropped != stat->last_drop_val)) { 294 trace_drop_common(NULL, NULL); 295 stat->last_drop_val = dev->stats.rx_dropped; 296 stat->last_rx = jiffies; 297 } 298 } 299 rcu_read_unlock(); 300 } 301 302 static struct net_dm_hw_entries * 303 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data) 304 { 305 struct net_dm_hw_entries *hw_entries; 306 unsigned long flags; 307 308 hw_entries = kzalloc_flex(*hw_entries, entries, dm_hit_limit); 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 raw_spin_lock_irqsave(&hw_data->lock, flags); 318 swap(hw_data->hw_entries, hw_entries); 319 raw_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 = raw_cpu_ptr(&dm_hw_cpu_data); 451 raw_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 strscpy(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 raw_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 enum skb_drop_reason reason, 495 const struct sock *rx_sk) 496 { 497 ktime_t tstamp = ktime_get_real(); 498 struct per_cpu_dm_data *data; 499 struct net_dm_skb_cb *cb; 500 struct sk_buff *nskb; 501 unsigned long flags; 502 503 if (!skb_mac_header_was_set(skb)) 504 return; 505 506 nskb = skb_clone(skb, GFP_ATOMIC); 507 if (!nskb) 508 return; 509 510 cb = NET_DM_SKB_CB(nskb); 511 cb->reason = reason; 512 cb->pc = location; 513 /* Override the timestamp because we care about the time when the 514 * packet was dropped. 515 */ 516 nskb->tstamp = tstamp; 517 518 data = raw_cpu_ptr(&dm_cpu_data); 519 520 spin_lock_irqsave(&data->drop_queue.lock, flags); 521 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 522 __skb_queue_tail(&data->drop_queue, nskb); 523 else 524 goto unlock_free; 525 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 526 527 schedule_work(&data->dm_alert_work); 528 529 return; 530 531 unlock_free: 532 u64_stats_update_begin(&data->stats.syncp); 533 u64_stats_inc(&data->stats.dropped); 534 u64_stats_update_end(&data->stats.syncp); 535 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 536 consume_skb(nskb); 537 } 538 539 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 540 struct napi_struct *napi, 541 int work, int budget) 542 { 543 } 544 545 static size_t net_dm_in_port_size(void) 546 { 547 /* NET_DM_ATTR_IN_PORT nest */ 548 return nla_total_size(0) + 549 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 550 nla_total_size(sizeof(u32)) + 551 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 552 nla_total_size(IFNAMSIZ + 1); 553 } 554 555 #define NET_DM_MAX_SYMBOL_LEN 40 556 #define NET_DM_MAX_REASON_LEN 50 557 558 static size_t net_dm_packet_report_size(size_t payload_len) 559 { 560 size_t size; 561 562 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 563 564 return NLMSG_ALIGN(size) + 565 /* NET_DM_ATTR_ORIGIN */ 566 nla_total_size(sizeof(u16)) + 567 /* NET_DM_ATTR_PC */ 568 nla_total_size_64bit(sizeof(u64)) + 569 /* NET_DM_ATTR_SYMBOL */ 570 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 571 /* NET_DM_ATTR_IN_PORT */ 572 net_dm_in_port_size() + 573 /* NET_DM_ATTR_TIMESTAMP */ 574 nla_total_size_64bit(sizeof(u64)) + 575 /* NET_DM_ATTR_ORIG_LEN */ 576 nla_total_size(sizeof(u32)) + 577 /* NET_DM_ATTR_PROTO */ 578 nla_total_size(sizeof(u16)) + 579 /* NET_DM_ATTR_REASON */ 580 nla_total_size(NET_DM_MAX_REASON_LEN + 1) + 581 /* NET_DM_ATTR_PAYLOAD */ 582 nla_total_size(payload_len); 583 } 584 585 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 586 const char *name) 587 { 588 struct nlattr *attr; 589 590 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 591 if (!attr) 592 return -EMSGSIZE; 593 594 if (ifindex && 595 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 596 goto nla_put_failure; 597 598 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 599 goto nla_put_failure; 600 601 nla_nest_end(msg, attr); 602 603 return 0; 604 605 nla_put_failure: 606 nla_nest_cancel(msg, attr); 607 return -EMSGSIZE; 608 } 609 610 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 611 size_t payload_len) 612 { 613 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); 614 const struct drop_reason_list *list = NULL; 615 unsigned int subsys, subsys_reason; 616 char buf[NET_DM_MAX_SYMBOL_LEN]; 617 struct nlattr *attr; 618 void *hdr; 619 int rc; 620 621 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 622 NET_DM_CMD_PACKET_ALERT); 623 if (!hdr) 624 return -EMSGSIZE; 625 626 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 627 goto nla_put_failure; 628 629 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, 630 NET_DM_ATTR_PAD)) 631 goto nla_put_failure; 632 633 rcu_read_lock(); 634 subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK); 635 if (subsys < SKB_DROP_REASON_SUBSYS_NUM) 636 list = rcu_dereference(drop_reasons_by_subsys[subsys]); 637 subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK; 638 if (!list || 639 subsys_reason >= list->n_reasons || 640 !list->reasons[subsys_reason] || 641 strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) { 642 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]); 643 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED; 644 } 645 if (nla_put_string(msg, NET_DM_ATTR_REASON, 646 list->reasons[subsys_reason])) { 647 rcu_read_unlock(); 648 goto nla_put_failure; 649 } 650 rcu_read_unlock(); 651 652 snprintf(buf, sizeof(buf), "%pS", cb->pc); 653 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 654 goto nla_put_failure; 655 656 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 657 if (rc) 658 goto nla_put_failure; 659 660 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 661 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 662 goto nla_put_failure; 663 664 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 665 goto nla_put_failure; 666 667 if (!payload_len) 668 goto out; 669 670 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 671 goto nla_put_failure; 672 673 attr = __nla_reserve(msg, NET_DM_ATTR_PAYLOAD, payload_len); 674 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 675 goto nla_put_failure; 676 677 out: 678 genlmsg_end(msg, hdr); 679 680 return 0; 681 682 nla_put_failure: 683 genlmsg_cancel(msg, hdr); 684 return -EMSGSIZE; 685 } 686 687 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 688 689 static void net_dm_packet_report(struct sk_buff *skb) 690 { 691 struct sk_buff *msg; 692 size_t payload_len; 693 int rc; 694 695 /* Make sure we start copying the packet from the MAC header */ 696 if (skb->data > skb_mac_header(skb)) 697 skb_push(skb, skb->data - skb_mac_header(skb)); 698 else 699 skb_pull(skb, skb_mac_header(skb) - skb->data); 700 701 /* Ensure packet fits inside a single netlink attribute */ 702 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 703 if (net_dm_trunc_len) 704 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 705 706 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 707 if (!msg) 708 goto out; 709 710 rc = net_dm_packet_report_fill(msg, skb, payload_len); 711 if (rc) { 712 nlmsg_free(msg); 713 goto out; 714 } 715 716 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 717 718 out: 719 consume_skb(skb); 720 } 721 722 static void net_dm_packet_work(struct work_struct *work) 723 { 724 struct per_cpu_dm_data *data; 725 struct sk_buff_head list; 726 struct sk_buff *skb; 727 unsigned long flags; 728 729 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 730 731 __skb_queue_head_init(&list); 732 733 spin_lock_irqsave(&data->drop_queue.lock, flags); 734 skb_queue_splice_tail_init(&data->drop_queue, &list); 735 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 736 737 while ((skb = __skb_dequeue(&list))) 738 net_dm_packet_report(skb); 739 } 740 741 static size_t 742 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) 743 { 744 return hw_metadata->fa_cookie ? 745 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 746 } 747 748 static size_t 749 net_dm_hw_packet_report_size(size_t payload_len, 750 const struct devlink_trap_metadata *hw_metadata) 751 { 752 size_t size; 753 754 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 755 756 return NLMSG_ALIGN(size) + 757 /* NET_DM_ATTR_ORIGIN */ 758 nla_total_size(sizeof(u16)) + 759 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 760 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 761 /* NET_DM_ATTR_HW_TRAP_NAME */ 762 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 763 /* NET_DM_ATTR_IN_PORT */ 764 net_dm_in_port_size() + 765 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 766 net_dm_flow_action_cookie_size(hw_metadata) + 767 /* NET_DM_ATTR_TIMESTAMP */ 768 nla_total_size_64bit(sizeof(u64)) + 769 /* NET_DM_ATTR_ORIG_LEN */ 770 nla_total_size(sizeof(u32)) + 771 /* NET_DM_ATTR_PROTO */ 772 nla_total_size(sizeof(u16)) + 773 /* NET_DM_ATTR_PAYLOAD */ 774 nla_total_size(payload_len); 775 } 776 777 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 778 struct sk_buff *skb, size_t payload_len) 779 { 780 struct devlink_trap_metadata *hw_metadata; 781 struct nlattr *attr; 782 void *hdr; 783 784 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 785 786 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 787 NET_DM_CMD_PACKET_ALERT); 788 if (!hdr) 789 return -EMSGSIZE; 790 791 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 792 goto nla_put_failure; 793 794 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 795 hw_metadata->trap_group_name)) 796 goto nla_put_failure; 797 798 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 799 hw_metadata->trap_name)) 800 goto nla_put_failure; 801 802 if (hw_metadata->input_dev) { 803 struct net_device *dev = hw_metadata->input_dev; 804 int rc; 805 806 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 807 dev->name); 808 if (rc) 809 goto nla_put_failure; 810 } 811 812 if (hw_metadata->fa_cookie && 813 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 814 hw_metadata->fa_cookie->cookie_len, 815 hw_metadata->fa_cookie->cookie)) 816 goto nla_put_failure; 817 818 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 819 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 820 goto nla_put_failure; 821 822 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 823 goto nla_put_failure; 824 825 if (!payload_len) 826 goto out; 827 828 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 829 goto nla_put_failure; 830 831 attr = __nla_reserve(msg, NET_DM_ATTR_PAYLOAD, payload_len); 832 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 833 goto nla_put_failure; 834 835 out: 836 genlmsg_end(msg, hdr); 837 838 return 0; 839 840 nla_put_failure: 841 genlmsg_cancel(msg, hdr); 842 return -EMSGSIZE; 843 } 844 845 static struct devlink_trap_metadata * 846 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) 847 { 848 const struct flow_action_cookie *fa_cookie; 849 struct devlink_trap_metadata *hw_metadata; 850 const char *trap_group_name; 851 const char *trap_name; 852 853 hw_metadata = kzalloc_obj(*hw_metadata, GFP_ATOMIC); 854 if (!hw_metadata) 855 return NULL; 856 857 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); 858 if (!trap_group_name) 859 goto free_hw_metadata; 860 hw_metadata->trap_group_name = trap_group_name; 861 862 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); 863 if (!trap_name) 864 goto free_trap_group; 865 hw_metadata->trap_name = trap_name; 866 867 if (metadata->fa_cookie) { 868 size_t cookie_size = sizeof(*fa_cookie) + 869 metadata->fa_cookie->cookie_len; 870 871 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, 872 GFP_ATOMIC); 873 if (!fa_cookie) 874 goto free_trap_name; 875 hw_metadata->fa_cookie = fa_cookie; 876 } 877 878 hw_metadata->input_dev = metadata->input_dev; 879 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker, 880 GFP_ATOMIC); 881 882 return hw_metadata; 883 884 free_trap_name: 885 kfree(trap_name); 886 free_trap_group: 887 kfree(trap_group_name); 888 free_hw_metadata: 889 kfree(hw_metadata); 890 return NULL; 891 } 892 893 static void 894 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) 895 { 896 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker); 897 kfree(hw_metadata->fa_cookie); 898 kfree(hw_metadata->trap_name); 899 kfree(hw_metadata->trap_group_name); 900 kfree(hw_metadata); 901 } 902 903 static void net_dm_hw_packet_report(struct sk_buff *skb) 904 { 905 struct devlink_trap_metadata *hw_metadata; 906 struct sk_buff *msg; 907 size_t payload_len; 908 int rc; 909 910 if (skb->data > skb_mac_header(skb)) 911 skb_push(skb, skb->data - skb_mac_header(skb)); 912 else 913 skb_pull(skb, skb_mac_header(skb) - skb->data); 914 915 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 916 if (net_dm_trunc_len) 917 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 918 919 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 920 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 921 GFP_KERNEL); 922 if (!msg) 923 goto out; 924 925 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 926 if (rc) { 927 nlmsg_free(msg); 928 goto out; 929 } 930 931 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 932 933 out: 934 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 935 consume_skb(skb); 936 } 937 938 static void net_dm_hw_packet_work(struct work_struct *work) 939 { 940 struct per_cpu_dm_data *hw_data; 941 struct sk_buff_head list; 942 struct sk_buff *skb; 943 unsigned long flags; 944 945 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 946 947 __skb_queue_head_init(&list); 948 949 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 950 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 951 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 952 953 while ((skb = __skb_dequeue(&list))) 954 net_dm_hw_packet_report(skb); 955 } 956 957 static void 958 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink, 959 struct sk_buff *skb, 960 const struct devlink_trap_metadata *metadata) 961 { 962 struct devlink_trap_metadata *n_hw_metadata; 963 ktime_t tstamp = ktime_get_real(); 964 struct per_cpu_dm_data *hw_data; 965 struct sk_buff *nskb; 966 unsigned long flags; 967 968 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 969 return; 970 971 if (!skb_mac_header_was_set(skb)) 972 return; 973 974 nskb = skb_clone(skb, GFP_ATOMIC); 975 if (!nskb) 976 return; 977 978 n_hw_metadata = net_dm_hw_metadata_copy(metadata); 979 if (!n_hw_metadata) 980 goto free; 981 982 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 983 nskb->tstamp = tstamp; 984 985 hw_data = raw_cpu_ptr(&dm_hw_cpu_data); 986 987 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 988 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 989 __skb_queue_tail(&hw_data->drop_queue, nskb); 990 else 991 goto unlock_free; 992 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 993 994 schedule_work(&hw_data->dm_alert_work); 995 996 return; 997 998 unlock_free: 999 u64_stats_update_begin(&hw_data->stats.syncp); 1000 u64_stats_inc(&hw_data->stats.dropped); 1001 u64_stats_update_end(&hw_data->stats.syncp); 1002 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 1003 net_dm_hw_metadata_free(n_hw_metadata); 1004 free: 1005 consume_skb(nskb); 1006 } 1007 1008 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 1009 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 1010 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 1011 .work_item_func = net_dm_packet_work, 1012 .hw_work_item_func = net_dm_hw_packet_work, 1013 .hw_trap_probe = net_dm_hw_trap_packet_probe, 1014 }; 1015 1016 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 1017 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 1018 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 1019 }; 1020 1021 #if IS_ENABLED(CONFIG_NET_DEVLINK) 1022 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1023 { 1024 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1025 } 1026 1027 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1028 { 1029 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1030 tracepoint_synchronize_unregister(); 1031 } 1032 #else 1033 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1034 { 1035 return -EOPNOTSUPP; 1036 } 1037 1038 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1039 { 1040 } 1041 #endif 1042 1043 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1044 { 1045 const struct net_dm_alert_ops *ops; 1046 int cpu, rc; 1047 1048 if (monitor_hw) { 1049 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1050 return -EAGAIN; 1051 } 1052 1053 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1054 1055 if (!try_module_get(THIS_MODULE)) { 1056 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1057 return -ENODEV; 1058 } 1059 1060 for_each_possible_cpu(cpu) { 1061 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1062 struct net_dm_hw_entries *hw_entries; 1063 1064 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1065 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1066 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1067 kfree(hw_entries); 1068 } 1069 1070 rc = net_dm_hw_probe_register(ops); 1071 if (rc) { 1072 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); 1073 goto err_module_put; 1074 } 1075 1076 monitor_hw = true; 1077 1078 return 0; 1079 1080 err_module_put: 1081 for_each_possible_cpu(cpu) { 1082 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1083 struct sk_buff *skb; 1084 1085 timer_shutdown_sync(&hw_data->send_timer); 1086 cancel_work_sync(&hw_data->dm_alert_work); 1087 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1088 struct devlink_trap_metadata *hw_metadata; 1089 1090 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1091 net_dm_hw_metadata_free(hw_metadata); 1092 consume_skb(skb); 1093 } 1094 } 1095 module_put(THIS_MODULE); 1096 return rc; 1097 } 1098 1099 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1100 { 1101 const struct net_dm_alert_ops *ops; 1102 int cpu; 1103 1104 if (!monitor_hw) { 1105 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1106 return; 1107 } 1108 1109 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1110 1111 monitor_hw = false; 1112 1113 net_dm_hw_probe_unregister(ops); 1114 1115 for_each_possible_cpu(cpu) { 1116 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1117 struct sk_buff *skb; 1118 1119 timer_shutdown_sync(&hw_data->send_timer); 1120 cancel_work_sync(&hw_data->dm_alert_work); 1121 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1122 struct devlink_trap_metadata *hw_metadata; 1123 1124 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1125 net_dm_hw_metadata_free(hw_metadata); 1126 consume_skb(skb); 1127 } 1128 } 1129 1130 module_put(THIS_MODULE); 1131 } 1132 1133 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1134 { 1135 const struct net_dm_alert_ops *ops; 1136 int cpu, rc; 1137 1138 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1139 1140 if (!try_module_get(THIS_MODULE)) { 1141 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1142 return -ENODEV; 1143 } 1144 1145 for_each_possible_cpu(cpu) { 1146 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1147 struct sk_buff *skb; 1148 1149 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1150 timer_setup(&data->send_timer, sched_send_work, 0); 1151 /* Allocate a new per-CPU skb for the summary alert message and 1152 * free the old one which might contain stale data from 1153 * previous tracing. 1154 */ 1155 skb = reset_per_cpu_data(data); 1156 consume_skb(skb); 1157 } 1158 1159 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1160 if (rc) { 1161 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1162 goto err_module_put; 1163 } 1164 1165 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1166 if (rc) { 1167 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1168 goto err_unregister_trace; 1169 } 1170 1171 return 0; 1172 1173 err_unregister_trace: 1174 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1175 tracepoint_synchronize_unregister(); 1176 err_module_put: 1177 for_each_possible_cpu(cpu) { 1178 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1179 struct sk_buff *skb; 1180 1181 timer_shutdown_sync(&data->send_timer); 1182 cancel_work_sync(&data->dm_alert_work); 1183 while ((skb = __skb_dequeue(&data->drop_queue))) 1184 consume_skb(skb); 1185 } 1186 module_put(THIS_MODULE); 1187 return rc; 1188 } 1189 1190 static void net_dm_trace_off_set(void) 1191 { 1192 const struct net_dm_alert_ops *ops; 1193 int cpu; 1194 1195 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1196 1197 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1198 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1199 1200 tracepoint_synchronize_unregister(); 1201 1202 /* Make sure we do not send notifications to user space after request 1203 * to stop tracing returns. 1204 */ 1205 for_each_possible_cpu(cpu) { 1206 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1207 struct sk_buff *skb; 1208 1209 timer_shutdown_sync(&data->send_timer); 1210 cancel_work_sync(&data->dm_alert_work); 1211 while ((skb = __skb_dequeue(&data->drop_queue))) 1212 consume_skb(skb); 1213 } 1214 1215 module_put(THIS_MODULE); 1216 } 1217 1218 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1219 { 1220 int rc = 0; 1221 1222 if (state == trace_state) { 1223 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1224 return -EAGAIN; 1225 } 1226 1227 switch (state) { 1228 case TRACE_ON: 1229 rc = net_dm_trace_on_set(extack); 1230 break; 1231 case TRACE_OFF: 1232 net_dm_trace_off_set(); 1233 break; 1234 default: 1235 rc = 1; 1236 break; 1237 } 1238 1239 if (!rc) 1240 trace_state = state; 1241 else 1242 rc = -EINPROGRESS; 1243 1244 return rc; 1245 } 1246 1247 static bool net_dm_is_monitoring(void) 1248 { 1249 return trace_state == TRACE_ON || monitor_hw; 1250 } 1251 1252 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1253 enum net_dm_alert_mode *p_alert_mode) 1254 { 1255 u8 val; 1256 1257 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1258 1259 switch (val) { 1260 case NET_DM_ALERT_MODE_SUMMARY: 1261 case NET_DM_ALERT_MODE_PACKET: 1262 *p_alert_mode = val; 1263 break; 1264 default: 1265 return -EINVAL; 1266 } 1267 1268 return 0; 1269 } 1270 1271 static int net_dm_alert_mode_set(struct genl_info *info) 1272 { 1273 struct netlink_ext_ack *extack = info->extack; 1274 enum net_dm_alert_mode alert_mode; 1275 int rc; 1276 1277 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1278 return 0; 1279 1280 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1281 if (rc) { 1282 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1283 return -EINVAL; 1284 } 1285 1286 net_dm_alert_mode = alert_mode; 1287 1288 return 0; 1289 } 1290 1291 static void net_dm_trunc_len_set(struct genl_info *info) 1292 { 1293 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1294 return; 1295 1296 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1297 } 1298 1299 static void net_dm_queue_len_set(struct genl_info *info) 1300 { 1301 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1302 return; 1303 1304 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1305 } 1306 1307 static int net_dm_cmd_config(struct sk_buff *skb, 1308 struct genl_info *info) 1309 { 1310 struct netlink_ext_ack *extack = info->extack; 1311 int rc; 1312 1313 if (net_dm_is_monitoring()) { 1314 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1315 return -EBUSY; 1316 } 1317 1318 rc = net_dm_alert_mode_set(info); 1319 if (rc) 1320 return rc; 1321 1322 net_dm_trunc_len_set(info); 1323 1324 net_dm_queue_len_set(info); 1325 1326 return 0; 1327 } 1328 1329 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1330 struct netlink_ext_ack *extack) 1331 { 1332 bool sw_set = false; 1333 int rc; 1334 1335 if (set_sw) { 1336 rc = set_all_monitor_traces(TRACE_ON, extack); 1337 if (rc) 1338 return rc; 1339 sw_set = true; 1340 } 1341 1342 if (set_hw) { 1343 rc = net_dm_hw_monitor_start(extack); 1344 if (rc) 1345 goto err_monitor_hw; 1346 } 1347 1348 return 0; 1349 1350 err_monitor_hw: 1351 if (sw_set) 1352 set_all_monitor_traces(TRACE_OFF, extack); 1353 return rc; 1354 } 1355 1356 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1357 struct netlink_ext_ack *extack) 1358 { 1359 if (set_hw) 1360 net_dm_hw_monitor_stop(extack); 1361 if (set_sw) 1362 set_all_monitor_traces(TRACE_OFF, extack); 1363 } 1364 1365 static int net_dm_cmd_trace(struct sk_buff *skb, 1366 struct genl_info *info) 1367 { 1368 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1369 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1370 struct netlink_ext_ack *extack = info->extack; 1371 1372 /* To maintain backward compatibility, we start / stop monitoring of 1373 * software drops if no flag is specified. 1374 */ 1375 if (!set_sw && !set_hw) 1376 set_sw = true; 1377 1378 switch (info->genlhdr->cmd) { 1379 case NET_DM_CMD_START: 1380 return net_dm_monitor_start(set_sw, set_hw, extack); 1381 case NET_DM_CMD_STOP: 1382 net_dm_monitor_stop(set_sw, set_hw, extack); 1383 return 0; 1384 } 1385 1386 return -EOPNOTSUPP; 1387 } 1388 1389 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1390 { 1391 void *hdr; 1392 1393 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1394 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1395 if (!hdr) 1396 return -EMSGSIZE; 1397 1398 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1399 goto nla_put_failure; 1400 1401 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1402 goto nla_put_failure; 1403 1404 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1405 goto nla_put_failure; 1406 1407 genlmsg_end(msg, hdr); 1408 1409 return 0; 1410 1411 nla_put_failure: 1412 genlmsg_cancel(msg, hdr); 1413 return -EMSGSIZE; 1414 } 1415 1416 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1417 { 1418 struct sk_buff *msg; 1419 int rc; 1420 1421 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1422 if (!msg) 1423 return -ENOMEM; 1424 1425 rc = net_dm_config_fill(msg, info); 1426 if (rc) 1427 goto free_msg; 1428 1429 return genlmsg_reply(msg, info); 1430 1431 free_msg: 1432 nlmsg_free(msg); 1433 return rc; 1434 } 1435 1436 static void net_dm_stats_read(struct net_dm_stats *stats) 1437 { 1438 int cpu; 1439 1440 memset(stats, 0, sizeof(*stats)); 1441 for_each_possible_cpu(cpu) { 1442 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1443 struct net_dm_stats *cpu_stats = &data->stats; 1444 unsigned int start; 1445 u64 dropped; 1446 1447 do { 1448 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1449 dropped = u64_stats_read(&cpu_stats->dropped); 1450 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1451 1452 u64_stats_add(&stats->dropped, dropped); 1453 } 1454 } 1455 1456 static int net_dm_stats_put(struct sk_buff *msg) 1457 { 1458 struct net_dm_stats stats; 1459 struct nlattr *attr; 1460 1461 net_dm_stats_read(&stats); 1462 1463 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1464 if (!attr) 1465 return -EMSGSIZE; 1466 1467 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1468 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1469 goto nla_put_failure; 1470 1471 nla_nest_end(msg, attr); 1472 1473 return 0; 1474 1475 nla_put_failure: 1476 nla_nest_cancel(msg, attr); 1477 return -EMSGSIZE; 1478 } 1479 1480 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1481 { 1482 int cpu; 1483 1484 memset(stats, 0, sizeof(*stats)); 1485 for_each_possible_cpu(cpu) { 1486 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1487 struct net_dm_stats *cpu_stats = &hw_data->stats; 1488 unsigned int start; 1489 u64 dropped; 1490 1491 do { 1492 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1493 dropped = u64_stats_read(&cpu_stats->dropped); 1494 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1495 1496 u64_stats_add(&stats->dropped, dropped); 1497 } 1498 } 1499 1500 static int net_dm_hw_stats_put(struct sk_buff *msg) 1501 { 1502 struct net_dm_stats stats; 1503 struct nlattr *attr; 1504 1505 net_dm_hw_stats_read(&stats); 1506 1507 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1508 if (!attr) 1509 return -EMSGSIZE; 1510 1511 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1512 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1513 goto nla_put_failure; 1514 1515 nla_nest_end(msg, attr); 1516 1517 return 0; 1518 1519 nla_put_failure: 1520 nla_nest_cancel(msg, attr); 1521 return -EMSGSIZE; 1522 } 1523 1524 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1525 { 1526 void *hdr; 1527 int rc; 1528 1529 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1530 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1531 if (!hdr) 1532 return -EMSGSIZE; 1533 1534 rc = net_dm_stats_put(msg); 1535 if (rc) 1536 goto nla_put_failure; 1537 1538 rc = net_dm_hw_stats_put(msg); 1539 if (rc) 1540 goto nla_put_failure; 1541 1542 genlmsg_end(msg, hdr); 1543 1544 return 0; 1545 1546 nla_put_failure: 1547 genlmsg_cancel(msg, hdr); 1548 return -EMSGSIZE; 1549 } 1550 1551 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1552 { 1553 struct sk_buff *msg; 1554 int rc; 1555 1556 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1557 if (!msg) 1558 return -ENOMEM; 1559 1560 rc = net_dm_stats_fill(msg, info); 1561 if (rc) 1562 goto free_msg; 1563 1564 return genlmsg_reply(msg, info); 1565 1566 free_msg: 1567 nlmsg_free(msg); 1568 return rc; 1569 } 1570 1571 static int dropmon_net_event(struct notifier_block *ev_block, 1572 unsigned long event, void *ptr) 1573 { 1574 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1575 struct dm_hw_stat_delta *stat; 1576 1577 switch (event) { 1578 case NETDEV_REGISTER: 1579 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private))) 1580 break; 1581 stat = kzalloc_obj(*stat); 1582 if (!stat) 1583 break; 1584 1585 stat->last_rx = jiffies; 1586 rcu_assign_pointer(dev->dm_private, stat); 1587 1588 break; 1589 case NETDEV_UNREGISTER: 1590 stat = rtnl_dereference(dev->dm_private); 1591 if (stat) { 1592 rcu_assign_pointer(dev->dm_private, NULL); 1593 kfree_rcu(stat, rcu); 1594 } 1595 break; 1596 } 1597 return NOTIFY_DONE; 1598 } 1599 1600 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1601 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1602 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1603 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1604 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1605 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1606 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1607 }; 1608 1609 static const struct genl_small_ops dropmon_ops[] = { 1610 { 1611 .cmd = NET_DM_CMD_CONFIG, 1612 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1613 .doit = net_dm_cmd_config, 1614 .flags = GENL_ADMIN_PERM, 1615 }, 1616 { 1617 .cmd = NET_DM_CMD_START, 1618 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1619 .doit = net_dm_cmd_trace, 1620 .flags = GENL_ADMIN_PERM, 1621 }, 1622 { 1623 .cmd = NET_DM_CMD_STOP, 1624 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1625 .doit = net_dm_cmd_trace, 1626 .flags = GENL_ADMIN_PERM, 1627 }, 1628 { 1629 .cmd = NET_DM_CMD_CONFIG_GET, 1630 .doit = net_dm_cmd_config_get, 1631 }, 1632 { 1633 .cmd = NET_DM_CMD_STATS_GET, 1634 .doit = net_dm_cmd_stats_get, 1635 }, 1636 }; 1637 1638 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops, 1639 struct sk_buff *skb, struct genl_info *info) 1640 { 1641 mutex_lock(&net_dm_mutex); 1642 1643 return 0; 1644 } 1645 1646 static void net_dm_nl_post_doit(const struct genl_split_ops *ops, 1647 struct sk_buff *skb, struct genl_info *info) 1648 { 1649 mutex_unlock(&net_dm_mutex); 1650 } 1651 1652 static struct genl_family net_drop_monitor_family __ro_after_init = { 1653 .hdrsize = 0, 1654 .name = "NET_DM", 1655 .version = 2, 1656 .maxattr = NET_DM_ATTR_MAX, 1657 .policy = net_dm_nl_policy, 1658 .pre_doit = net_dm_nl_pre_doit, 1659 .post_doit = net_dm_nl_post_doit, 1660 .module = THIS_MODULE, 1661 .small_ops = dropmon_ops, 1662 .n_small_ops = ARRAY_SIZE(dropmon_ops), 1663 .resv_start_op = NET_DM_CMD_STATS_GET + 1, 1664 .mcgrps = dropmon_mcgrps, 1665 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1666 }; 1667 1668 static struct notifier_block dropmon_net_notifier = { 1669 .notifier_call = dropmon_net_event 1670 }; 1671 1672 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1673 { 1674 raw_spin_lock_init(&data->lock); 1675 skb_queue_head_init(&data->drop_queue); 1676 u64_stats_init(&data->stats.syncp); 1677 } 1678 1679 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1680 { 1681 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1682 } 1683 1684 static void net_dm_cpu_data_init(int cpu) 1685 { 1686 struct per_cpu_dm_data *data; 1687 1688 data = &per_cpu(dm_cpu_data, cpu); 1689 __net_dm_cpu_data_init(data); 1690 } 1691 1692 static void net_dm_cpu_data_fini(int cpu) 1693 { 1694 struct per_cpu_dm_data *data; 1695 1696 data = &per_cpu(dm_cpu_data, cpu); 1697 /* At this point, we should have exclusive access 1698 * to this struct and can free the skb inside it. 1699 */ 1700 consume_skb(data->skb); 1701 __net_dm_cpu_data_fini(data); 1702 } 1703 1704 static void net_dm_hw_cpu_data_init(int cpu) 1705 { 1706 struct per_cpu_dm_data *hw_data; 1707 1708 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1709 __net_dm_cpu_data_init(hw_data); 1710 } 1711 1712 static void net_dm_hw_cpu_data_fini(int cpu) 1713 { 1714 struct per_cpu_dm_data *hw_data; 1715 1716 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1717 kfree(hw_data->hw_entries); 1718 __net_dm_cpu_data_fini(hw_data); 1719 } 1720 1721 static int __init init_net_drop_monitor(void) 1722 { 1723 int cpu, rc; 1724 1725 pr_info("Initializing network drop monitor service\n"); 1726 1727 if (sizeof(void *) > 8) { 1728 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1729 return -ENOSPC; 1730 } 1731 1732 for_each_possible_cpu(cpu) { 1733 net_dm_cpu_data_init(cpu); 1734 net_dm_hw_cpu_data_init(cpu); 1735 } 1736 1737 rc = register_netdevice_notifier(&dropmon_net_notifier); 1738 if (rc < 0) { 1739 pr_crit("Failed to register netdevice notifier\n"); 1740 return rc; 1741 } 1742 1743 rc = genl_register_family(&net_drop_monitor_family); 1744 if (rc) { 1745 pr_err("Could not create drop monitor netlink family\n"); 1746 goto out_unreg; 1747 } 1748 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1749 1750 rc = 0; 1751 1752 goto out; 1753 1754 out_unreg: 1755 WARN_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1756 out: 1757 return rc; 1758 } 1759 1760 static void exit_net_drop_monitor(void) 1761 { 1762 int cpu; 1763 1764 /* 1765 * Because of the module_get/put we do in the trace state change path 1766 * we are guaranteed not to have any current users when we get here 1767 */ 1768 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1769 1770 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1771 1772 for_each_possible_cpu(cpu) { 1773 net_dm_hw_cpu_data_fini(cpu); 1774 net_dm_cpu_data_fini(cpu); 1775 } 1776 } 1777 1778 module_init(init_net_drop_monitor); 1779 module_exit(exit_net_drop_monitor); 1780 1781 MODULE_LICENSE("GPL v2"); 1782 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1783 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1784 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1785