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