1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Monitoring code for network dropped packet alerts 4 * 5 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/netdevice.h> 11 #include <linux/etherdevice.h> 12 #include <linux/string.h> 13 #include <linux/if_arp.h> 14 #include <linux/inetdevice.h> 15 #include <linux/inet.h> 16 #include <linux/interrupt.h> 17 #include <linux/netpoll.h> 18 #include <linux/sched.h> 19 #include <linux/delay.h> 20 #include <linux/types.h> 21 #include <linux/workqueue.h> 22 #include <linux/netlink.h> 23 #include <linux/net_dropmon.h> 24 #include <linux/percpu.h> 25 #include <linux/timer.h> 26 #include <linux/bitops.h> 27 #include <linux/slab.h> 28 #include <linux/module.h> 29 #include <net/genetlink.h> 30 #include <net/netevent.h> 31 #include <net/flow_offload.h> 32 #include <net/devlink.h> 33 34 #include <trace/events/skb.h> 35 #include <trace/events/napi.h> 36 #include <trace/events/devlink.h> 37 38 #include <asm/unaligned.h> 39 40 #define TRACE_ON 1 41 #define TRACE_OFF 0 42 43 /* 44 * Globals, our netlink socket pointer 45 * and the work handle that will send up 46 * netlink alerts 47 */ 48 static int trace_state = TRACE_OFF; 49 static bool monitor_hw; 50 51 /* net_dm_mutex 52 * 53 * An overall lock guarding every operation coming from userspace. 54 * It also guards the global 'hw_stats_list' list. 55 */ 56 static DEFINE_MUTEX(net_dm_mutex); 57 58 struct net_dm_stats { 59 u64 dropped; 60 struct u64_stats_sync syncp; 61 }; 62 63 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40 64 65 struct net_dm_hw_entry { 66 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN]; 67 u32 count; 68 }; 69 70 struct net_dm_hw_entries { 71 u32 num_entries; 72 struct net_dm_hw_entry entries[]; 73 }; 74 75 struct per_cpu_dm_data { 76 spinlock_t lock; /* Protects 'skb', 'hw_entries' and 77 * 'send_timer' 78 */ 79 union { 80 struct sk_buff *skb; 81 struct net_dm_hw_entries *hw_entries; 82 }; 83 struct sk_buff_head drop_queue; 84 struct work_struct dm_alert_work; 85 struct timer_list send_timer; 86 struct net_dm_stats stats; 87 }; 88 89 struct dm_hw_stat_delta { 90 struct net_device *dev; 91 unsigned long last_rx; 92 struct list_head list; 93 struct rcu_head rcu; 94 unsigned long last_drop_val; 95 }; 96 97 static struct genl_family net_drop_monitor_family; 98 99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); 100 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data); 101 102 static int dm_hit_limit = 64; 103 static int dm_delay = 1; 104 static unsigned long dm_hw_check_delta = 2*HZ; 105 static LIST_HEAD(hw_stats_list); 106 107 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY; 108 static u32 net_dm_trunc_len; 109 static u32 net_dm_queue_len = 1000; 110 111 struct net_dm_alert_ops { 112 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, 113 void *location, 114 enum skb_drop_reason reason); 115 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi, 116 int work, int budget); 117 void (*work_item_func)(struct work_struct *work); 118 void (*hw_work_item_func)(struct work_struct *work); 119 void (*hw_trap_probe)(void *ignore, const struct devlink *devlink, 120 struct sk_buff *skb, 121 const struct devlink_trap_metadata *metadata); 122 }; 123 124 struct net_dm_skb_cb { 125 union { 126 struct devlink_trap_metadata *hw_metadata; 127 void *pc; 128 }; 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 al += sizeof(struct nlattr); 145 146 skb = genlmsg_new(al, GFP_KERNEL); 147 148 if (!skb) 149 goto err; 150 151 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family, 152 0, NET_DM_CMD_ALERT); 153 if (!msg_header) { 154 nlmsg_free(skb); 155 skb = NULL; 156 goto err; 157 } 158 nla = nla_reserve(skb, NLA_UNSPEC, 159 sizeof(struct net_dm_alert_msg)); 160 if (!nla) { 161 nlmsg_free(skb); 162 skb = NULL; 163 goto err; 164 } 165 msg = nla_data(nla); 166 memset(msg, 0, al); 167 goto out; 168 169 err: 170 mod_timer(&data->send_timer, jiffies + HZ / 10); 171 out: 172 spin_lock_irqsave(&data->lock, flags); 173 swap(data->skb, skb); 174 spin_unlock_irqrestore(&data->lock, flags); 175 176 if (skb) { 177 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; 178 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh); 179 180 genlmsg_end(skb, genlmsg_data(gnlh)); 181 } 182 183 return skb; 184 } 185 186 static const struct genl_multicast_group dropmon_mcgrps[] = { 187 { .name = "events", }, 188 }; 189 190 static void send_dm_alert(struct work_struct *work) 191 { 192 struct sk_buff *skb; 193 struct per_cpu_dm_data *data; 194 195 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 196 197 skb = reset_per_cpu_data(data); 198 199 if (skb) 200 genlmsg_multicast(&net_drop_monitor_family, skb, 0, 201 0, GFP_KERNEL); 202 } 203 204 /* 205 * This is the timer function to delay the sending of an alert 206 * in the event that more drops will arrive during the 207 * hysteresis period. 208 */ 209 static void sched_send_work(struct timer_list *t) 210 { 211 struct per_cpu_dm_data *data = from_timer(data, t, send_timer); 212 213 schedule_work(&data->dm_alert_work); 214 } 215 216 static void trace_drop_common(struct sk_buff *skb, void *location) 217 { 218 struct net_dm_alert_msg *msg; 219 struct net_dm_drop_point *point; 220 struct nlmsghdr *nlh; 221 struct nlattr *nla; 222 int i; 223 struct sk_buff *dskb; 224 struct per_cpu_dm_data *data; 225 unsigned long flags; 226 227 local_irq_save(flags); 228 data = this_cpu_ptr(&dm_cpu_data); 229 spin_lock(&data->lock); 230 dskb = data->skb; 231 232 if (!dskb) 233 goto out; 234 235 nlh = (struct nlmsghdr *)dskb->data; 236 nla = genlmsg_data(nlmsg_data(nlh)); 237 msg = nla_data(nla); 238 point = msg->points; 239 for (i = 0; i < msg->entries; i++) { 240 if (!memcmp(&location, &point->pc, sizeof(void *))) { 241 point->count++; 242 goto out; 243 } 244 point++; 245 } 246 if (msg->entries == dm_hit_limit) 247 goto out; 248 /* 249 * We need to create a new entry 250 */ 251 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point)); 252 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); 253 memcpy(point->pc, &location, sizeof(void *)); 254 point->count = 1; 255 msg->entries++; 256 257 if (!timer_pending(&data->send_timer)) { 258 data->send_timer.expires = jiffies + dm_delay * HZ; 259 add_timer(&data->send_timer); 260 } 261 262 out: 263 spin_unlock_irqrestore(&data->lock, flags); 264 } 265 266 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, 267 void *location, 268 enum skb_drop_reason reason) 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 dm_hw_stat_delta *new_stat; 277 278 /* 279 * Don't check napi structures with no associated device 280 */ 281 if (!napi->dev) 282 return; 283 284 rcu_read_lock(); 285 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) { 286 /* 287 * only add a note to our monitor buffer if: 288 * 1) this is the dev we received on 289 * 2) its after the last_rx delta 290 * 3) our rx_dropped count has gone up 291 */ 292 if ((new_stat->dev == napi->dev) && 293 (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) && 294 (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) { 295 trace_drop_common(NULL, NULL); 296 new_stat->last_drop_val = napi->dev->stats.rx_dropped; 297 new_stat->last_rx = jiffies; 298 break; 299 } 300 } 301 rcu_read_unlock(); 302 } 303 304 static struct net_dm_hw_entries * 305 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data) 306 { 307 struct net_dm_hw_entries *hw_entries; 308 unsigned long flags; 309 310 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit), 311 GFP_KERNEL); 312 if (!hw_entries) { 313 /* If the memory allocation failed, we try to perform another 314 * allocation in 1/10 second. Otherwise, the probe function 315 * will constantly bail out. 316 */ 317 mod_timer(&hw_data->send_timer, jiffies + HZ / 10); 318 } 319 320 spin_lock_irqsave(&hw_data->lock, flags); 321 swap(hw_data->hw_entries, hw_entries); 322 spin_unlock_irqrestore(&hw_data->lock, flags); 323 324 return hw_entries; 325 } 326 327 static int net_dm_hw_entry_put(struct sk_buff *msg, 328 const struct net_dm_hw_entry *hw_entry) 329 { 330 struct nlattr *attr; 331 332 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY); 333 if (!attr) 334 return -EMSGSIZE; 335 336 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name)) 337 goto nla_put_failure; 338 339 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count)) 340 goto nla_put_failure; 341 342 nla_nest_end(msg, attr); 343 344 return 0; 345 346 nla_put_failure: 347 nla_nest_cancel(msg, attr); 348 return -EMSGSIZE; 349 } 350 351 static int net_dm_hw_entries_put(struct sk_buff *msg, 352 const struct net_dm_hw_entries *hw_entries) 353 { 354 struct nlattr *attr; 355 int i; 356 357 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES); 358 if (!attr) 359 return -EMSGSIZE; 360 361 for (i = 0; i < hw_entries->num_entries; i++) { 362 int rc; 363 364 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]); 365 if (rc) 366 goto nla_put_failure; 367 } 368 369 nla_nest_end(msg, attr); 370 371 return 0; 372 373 nla_put_failure: 374 nla_nest_cancel(msg, attr); 375 return -EMSGSIZE; 376 } 377 378 static int 379 net_dm_hw_summary_report_fill(struct sk_buff *msg, 380 const struct net_dm_hw_entries *hw_entries) 381 { 382 struct net_dm_alert_msg anc_hdr = { 0 }; 383 void *hdr; 384 int rc; 385 386 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 387 NET_DM_CMD_ALERT); 388 if (!hdr) 389 return -EMSGSIZE; 390 391 /* We need to put the ancillary header in order not to break user 392 * space. 393 */ 394 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr)) 395 goto nla_put_failure; 396 397 rc = net_dm_hw_entries_put(msg, hw_entries); 398 if (rc) 399 goto nla_put_failure; 400 401 genlmsg_end(msg, hdr); 402 403 return 0; 404 405 nla_put_failure: 406 genlmsg_cancel(msg, hdr); 407 return -EMSGSIZE; 408 } 409 410 static void net_dm_hw_summary_work(struct work_struct *work) 411 { 412 struct net_dm_hw_entries *hw_entries; 413 struct per_cpu_dm_data *hw_data; 414 struct sk_buff *msg; 415 int rc; 416 417 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 418 419 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 420 if (!hw_entries) 421 return; 422 423 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 424 if (!msg) 425 goto out; 426 427 rc = net_dm_hw_summary_report_fill(msg, hw_entries); 428 if (rc) { 429 nlmsg_free(msg); 430 goto out; 431 } 432 433 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 434 435 out: 436 kfree(hw_entries); 437 } 438 439 static void 440 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink, 441 struct sk_buff *skb, 442 const struct devlink_trap_metadata *metadata) 443 { 444 struct net_dm_hw_entries *hw_entries; 445 struct net_dm_hw_entry *hw_entry; 446 struct per_cpu_dm_data *hw_data; 447 unsigned long flags; 448 int i; 449 450 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 451 return; 452 453 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 454 spin_lock_irqsave(&hw_data->lock, flags); 455 hw_entries = hw_data->hw_entries; 456 457 if (!hw_entries) 458 goto out; 459 460 for (i = 0; i < hw_entries->num_entries; i++) { 461 hw_entry = &hw_entries->entries[i]; 462 if (!strncmp(hw_entry->trap_name, metadata->trap_name, 463 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) { 464 hw_entry->count++; 465 goto out; 466 } 467 } 468 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit)) 469 goto out; 470 471 hw_entry = &hw_entries->entries[hw_entries->num_entries]; 472 strlcpy(hw_entry->trap_name, metadata->trap_name, 473 NET_DM_MAX_HW_TRAP_NAME_LEN - 1); 474 hw_entry->count = 1; 475 hw_entries->num_entries++; 476 477 if (!timer_pending(&hw_data->send_timer)) { 478 hw_data->send_timer.expires = jiffies + dm_delay * HZ; 479 add_timer(&hw_data->send_timer); 480 } 481 482 out: 483 spin_unlock_irqrestore(&hw_data->lock, flags); 484 } 485 486 static const struct net_dm_alert_ops net_dm_alert_summary_ops = { 487 .kfree_skb_probe = trace_kfree_skb_hit, 488 .napi_poll_probe = trace_napi_poll_hit, 489 .work_item_func = send_dm_alert, 490 .hw_work_item_func = net_dm_hw_summary_work, 491 .hw_trap_probe = net_dm_hw_trap_summary_probe, 492 }; 493 494 static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 495 struct sk_buff *skb, 496 void *location, 497 enum skb_drop_reason reason) 498 { 499 ktime_t tstamp = ktime_get_real(); 500 struct per_cpu_dm_data *data; 501 struct sk_buff *nskb; 502 unsigned long flags; 503 504 if (!skb_mac_header_was_set(skb)) 505 return; 506 507 nskb = skb_clone(skb, GFP_ATOMIC); 508 if (!nskb) 509 return; 510 511 NET_DM_SKB_CB(nskb)->pc = location; 512 /* Override the timestamp because we care about the time when the 513 * packet was dropped. 514 */ 515 nskb->tstamp = tstamp; 516 517 data = this_cpu_ptr(&dm_cpu_data); 518 519 spin_lock_irqsave(&data->drop_queue.lock, flags); 520 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 521 __skb_queue_tail(&data->drop_queue, nskb); 522 else 523 goto unlock_free; 524 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 525 526 schedule_work(&data->dm_alert_work); 527 528 return; 529 530 unlock_free: 531 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 532 u64_stats_update_begin(&data->stats.syncp); 533 data->stats.dropped++; 534 u64_stats_update_end(&data->stats.syncp); 535 consume_skb(nskb); 536 } 537 538 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 539 struct napi_struct *napi, 540 int work, int budget) 541 { 542 } 543 544 static size_t net_dm_in_port_size(void) 545 { 546 /* NET_DM_ATTR_IN_PORT nest */ 547 return nla_total_size(0) + 548 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 549 nla_total_size(sizeof(u32)) + 550 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 551 nla_total_size(IFNAMSIZ + 1); 552 } 553 554 #define NET_DM_MAX_SYMBOL_LEN 40 555 556 static size_t net_dm_packet_report_size(size_t payload_len) 557 { 558 size_t size; 559 560 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 561 562 return NLMSG_ALIGN(size) + 563 /* NET_DM_ATTR_ORIGIN */ 564 nla_total_size(sizeof(u16)) + 565 /* NET_DM_ATTR_PC */ 566 nla_total_size(sizeof(u64)) + 567 /* NET_DM_ATTR_SYMBOL */ 568 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 569 /* NET_DM_ATTR_IN_PORT */ 570 net_dm_in_port_size() + 571 /* NET_DM_ATTR_TIMESTAMP */ 572 nla_total_size(sizeof(u64)) + 573 /* NET_DM_ATTR_ORIG_LEN */ 574 nla_total_size(sizeof(u32)) + 575 /* NET_DM_ATTR_PROTO */ 576 nla_total_size(sizeof(u16)) + 577 /* NET_DM_ATTR_PAYLOAD */ 578 nla_total_size(payload_len); 579 } 580 581 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 582 const char *name) 583 { 584 struct nlattr *attr; 585 586 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 587 if (!attr) 588 return -EMSGSIZE; 589 590 if (ifindex && 591 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 592 goto nla_put_failure; 593 594 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 595 goto nla_put_failure; 596 597 nla_nest_end(msg, attr); 598 599 return 0; 600 601 nla_put_failure: 602 nla_nest_cancel(msg, attr); 603 return -EMSGSIZE; 604 } 605 606 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 607 size_t payload_len) 608 { 609 u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; 610 char buf[NET_DM_MAX_SYMBOL_LEN]; 611 struct nlattr *attr; 612 void *hdr; 613 int rc; 614 615 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 616 NET_DM_CMD_PACKET_ALERT); 617 if (!hdr) 618 return -EMSGSIZE; 619 620 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 621 goto nla_put_failure; 622 623 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) 624 goto nla_put_failure; 625 626 snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); 627 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 628 goto nla_put_failure; 629 630 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 631 if (rc) 632 goto nla_put_failure; 633 634 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 635 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 636 goto nla_put_failure; 637 638 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 639 goto nla_put_failure; 640 641 if (!payload_len) 642 goto out; 643 644 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 645 goto nla_put_failure; 646 647 attr = skb_put(msg, nla_total_size(payload_len)); 648 attr->nla_type = NET_DM_ATTR_PAYLOAD; 649 attr->nla_len = nla_attr_size(payload_len); 650 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 651 goto nla_put_failure; 652 653 out: 654 genlmsg_end(msg, hdr); 655 656 return 0; 657 658 nla_put_failure: 659 genlmsg_cancel(msg, hdr); 660 return -EMSGSIZE; 661 } 662 663 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 664 665 static void net_dm_packet_report(struct sk_buff *skb) 666 { 667 struct sk_buff *msg; 668 size_t payload_len; 669 int rc; 670 671 /* Make sure we start copying the packet from the MAC header */ 672 if (skb->data > skb_mac_header(skb)) 673 skb_push(skb, skb->data - skb_mac_header(skb)); 674 else 675 skb_pull(skb, skb_mac_header(skb) - skb->data); 676 677 /* Ensure packet fits inside a single netlink attribute */ 678 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 679 if (net_dm_trunc_len) 680 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 681 682 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 683 if (!msg) 684 goto out; 685 686 rc = net_dm_packet_report_fill(msg, skb, payload_len); 687 if (rc) { 688 nlmsg_free(msg); 689 goto out; 690 } 691 692 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 693 694 out: 695 consume_skb(skb); 696 } 697 698 static void net_dm_packet_work(struct work_struct *work) 699 { 700 struct per_cpu_dm_data *data; 701 struct sk_buff_head list; 702 struct sk_buff *skb; 703 unsigned long flags; 704 705 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 706 707 __skb_queue_head_init(&list); 708 709 spin_lock_irqsave(&data->drop_queue.lock, flags); 710 skb_queue_splice_tail_init(&data->drop_queue, &list); 711 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 712 713 while ((skb = __skb_dequeue(&list))) 714 net_dm_packet_report(skb); 715 } 716 717 static size_t 718 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) 719 { 720 return hw_metadata->fa_cookie ? 721 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 722 } 723 724 static size_t 725 net_dm_hw_packet_report_size(size_t payload_len, 726 const struct devlink_trap_metadata *hw_metadata) 727 { 728 size_t size; 729 730 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 731 732 return NLMSG_ALIGN(size) + 733 /* NET_DM_ATTR_ORIGIN */ 734 nla_total_size(sizeof(u16)) + 735 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 736 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 737 /* NET_DM_ATTR_HW_TRAP_NAME */ 738 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 739 /* NET_DM_ATTR_IN_PORT */ 740 net_dm_in_port_size() + 741 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 742 net_dm_flow_action_cookie_size(hw_metadata) + 743 /* NET_DM_ATTR_TIMESTAMP */ 744 nla_total_size(sizeof(u64)) + 745 /* NET_DM_ATTR_ORIG_LEN */ 746 nla_total_size(sizeof(u32)) + 747 /* NET_DM_ATTR_PROTO */ 748 nla_total_size(sizeof(u16)) + 749 /* NET_DM_ATTR_PAYLOAD */ 750 nla_total_size(payload_len); 751 } 752 753 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 754 struct sk_buff *skb, size_t payload_len) 755 { 756 struct devlink_trap_metadata *hw_metadata; 757 struct nlattr *attr; 758 void *hdr; 759 760 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 761 762 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 763 NET_DM_CMD_PACKET_ALERT); 764 if (!hdr) 765 return -EMSGSIZE; 766 767 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 768 goto nla_put_failure; 769 770 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 771 hw_metadata->trap_group_name)) 772 goto nla_put_failure; 773 774 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 775 hw_metadata->trap_name)) 776 goto nla_put_failure; 777 778 if (hw_metadata->input_dev) { 779 struct net_device *dev = hw_metadata->input_dev; 780 int rc; 781 782 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 783 dev->name); 784 if (rc) 785 goto nla_put_failure; 786 } 787 788 if (hw_metadata->fa_cookie && 789 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 790 hw_metadata->fa_cookie->cookie_len, 791 hw_metadata->fa_cookie->cookie)) 792 goto nla_put_failure; 793 794 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 795 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 796 goto nla_put_failure; 797 798 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 799 goto nla_put_failure; 800 801 if (!payload_len) 802 goto out; 803 804 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 805 goto nla_put_failure; 806 807 attr = skb_put(msg, nla_total_size(payload_len)); 808 attr->nla_type = NET_DM_ATTR_PAYLOAD; 809 attr->nla_len = nla_attr_size(payload_len); 810 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 811 goto nla_put_failure; 812 813 out: 814 genlmsg_end(msg, hdr); 815 816 return 0; 817 818 nla_put_failure: 819 genlmsg_cancel(msg, hdr); 820 return -EMSGSIZE; 821 } 822 823 static struct devlink_trap_metadata * 824 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) 825 { 826 const struct flow_action_cookie *fa_cookie; 827 struct devlink_trap_metadata *hw_metadata; 828 const char *trap_group_name; 829 const char *trap_name; 830 831 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); 832 if (!hw_metadata) 833 return NULL; 834 835 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); 836 if (!trap_group_name) 837 goto free_hw_metadata; 838 hw_metadata->trap_group_name = trap_group_name; 839 840 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); 841 if (!trap_name) 842 goto free_trap_group; 843 hw_metadata->trap_name = trap_name; 844 845 if (metadata->fa_cookie) { 846 size_t cookie_size = sizeof(*fa_cookie) + 847 metadata->fa_cookie->cookie_len; 848 849 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, 850 GFP_ATOMIC); 851 if (!fa_cookie) 852 goto free_trap_name; 853 hw_metadata->fa_cookie = fa_cookie; 854 } 855 856 hw_metadata->input_dev = metadata->input_dev; 857 dev_hold_track(hw_metadata->input_dev, &hw_metadata->dev_tracker, GFP_ATOMIC); 858 859 return hw_metadata; 860 861 free_trap_name: 862 kfree(trap_name); 863 free_trap_group: 864 kfree(trap_group_name); 865 free_hw_metadata: 866 kfree(hw_metadata); 867 return NULL; 868 } 869 870 static void 871 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) 872 { 873 dev_put_track(hw_metadata->input_dev, &hw_metadata->dev_tracker); 874 kfree(hw_metadata->fa_cookie); 875 kfree(hw_metadata->trap_name); 876 kfree(hw_metadata->trap_group_name); 877 kfree(hw_metadata); 878 } 879 880 static void net_dm_hw_packet_report(struct sk_buff *skb) 881 { 882 struct devlink_trap_metadata *hw_metadata; 883 struct sk_buff *msg; 884 size_t payload_len; 885 int rc; 886 887 if (skb->data > skb_mac_header(skb)) 888 skb_push(skb, skb->data - skb_mac_header(skb)); 889 else 890 skb_pull(skb, skb_mac_header(skb) - skb->data); 891 892 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 893 if (net_dm_trunc_len) 894 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 895 896 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 897 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 898 GFP_KERNEL); 899 if (!msg) 900 goto out; 901 902 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 903 if (rc) { 904 nlmsg_free(msg); 905 goto out; 906 } 907 908 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 909 910 out: 911 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 912 consume_skb(skb); 913 } 914 915 static void net_dm_hw_packet_work(struct work_struct *work) 916 { 917 struct per_cpu_dm_data *hw_data; 918 struct sk_buff_head list; 919 struct sk_buff *skb; 920 unsigned long flags; 921 922 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 923 924 __skb_queue_head_init(&list); 925 926 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 927 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 928 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 929 930 while ((skb = __skb_dequeue(&list))) 931 net_dm_hw_packet_report(skb); 932 } 933 934 static void 935 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink, 936 struct sk_buff *skb, 937 const struct devlink_trap_metadata *metadata) 938 { 939 struct devlink_trap_metadata *n_hw_metadata; 940 ktime_t tstamp = ktime_get_real(); 941 struct per_cpu_dm_data *hw_data; 942 struct sk_buff *nskb; 943 unsigned long flags; 944 945 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 946 return; 947 948 if (!skb_mac_header_was_set(skb)) 949 return; 950 951 nskb = skb_clone(skb, GFP_ATOMIC); 952 if (!nskb) 953 return; 954 955 n_hw_metadata = net_dm_hw_metadata_copy(metadata); 956 if (!n_hw_metadata) 957 goto free; 958 959 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 960 nskb->tstamp = tstamp; 961 962 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 963 964 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 965 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 966 __skb_queue_tail(&hw_data->drop_queue, nskb); 967 else 968 goto unlock_free; 969 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 970 971 schedule_work(&hw_data->dm_alert_work); 972 973 return; 974 975 unlock_free: 976 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 977 u64_stats_update_begin(&hw_data->stats.syncp); 978 hw_data->stats.dropped++; 979 u64_stats_update_end(&hw_data->stats.syncp); 980 net_dm_hw_metadata_free(n_hw_metadata); 981 free: 982 consume_skb(nskb); 983 } 984 985 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 986 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 987 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 988 .work_item_func = net_dm_packet_work, 989 .hw_work_item_func = net_dm_hw_packet_work, 990 .hw_trap_probe = net_dm_hw_trap_packet_probe, 991 }; 992 993 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 994 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 995 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 996 }; 997 998 #if IS_ENABLED(CONFIG_NET_DEVLINK) 999 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1000 { 1001 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1002 } 1003 1004 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1005 { 1006 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1007 tracepoint_synchronize_unregister(); 1008 } 1009 #else 1010 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1011 { 1012 return -EOPNOTSUPP; 1013 } 1014 1015 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1016 { 1017 } 1018 #endif 1019 1020 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1021 { 1022 const struct net_dm_alert_ops *ops; 1023 int cpu, rc; 1024 1025 if (monitor_hw) { 1026 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1027 return -EAGAIN; 1028 } 1029 1030 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1031 1032 if (!try_module_get(THIS_MODULE)) { 1033 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1034 return -ENODEV; 1035 } 1036 1037 for_each_possible_cpu(cpu) { 1038 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1039 struct net_dm_hw_entries *hw_entries; 1040 1041 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1042 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1043 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1044 kfree(hw_entries); 1045 } 1046 1047 rc = net_dm_hw_probe_register(ops); 1048 if (rc) { 1049 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); 1050 goto err_module_put; 1051 } 1052 1053 monitor_hw = true; 1054 1055 return 0; 1056 1057 err_module_put: 1058 for_each_possible_cpu(cpu) { 1059 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1060 struct sk_buff *skb; 1061 1062 del_timer_sync(&hw_data->send_timer); 1063 cancel_work_sync(&hw_data->dm_alert_work); 1064 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1065 struct devlink_trap_metadata *hw_metadata; 1066 1067 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1068 net_dm_hw_metadata_free(hw_metadata); 1069 consume_skb(skb); 1070 } 1071 } 1072 module_put(THIS_MODULE); 1073 return rc; 1074 } 1075 1076 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1077 { 1078 const struct net_dm_alert_ops *ops; 1079 int cpu; 1080 1081 if (!monitor_hw) { 1082 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1083 return; 1084 } 1085 1086 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1087 1088 monitor_hw = false; 1089 1090 net_dm_hw_probe_unregister(ops); 1091 1092 for_each_possible_cpu(cpu) { 1093 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1094 struct sk_buff *skb; 1095 1096 del_timer_sync(&hw_data->send_timer); 1097 cancel_work_sync(&hw_data->dm_alert_work); 1098 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1099 struct devlink_trap_metadata *hw_metadata; 1100 1101 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1102 net_dm_hw_metadata_free(hw_metadata); 1103 consume_skb(skb); 1104 } 1105 } 1106 1107 module_put(THIS_MODULE); 1108 } 1109 1110 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1111 { 1112 const struct net_dm_alert_ops *ops; 1113 int cpu, rc; 1114 1115 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1116 1117 if (!try_module_get(THIS_MODULE)) { 1118 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1119 return -ENODEV; 1120 } 1121 1122 for_each_possible_cpu(cpu) { 1123 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1124 struct sk_buff *skb; 1125 1126 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1127 timer_setup(&data->send_timer, sched_send_work, 0); 1128 /* Allocate a new per-CPU skb for the summary alert message and 1129 * free the old one which might contain stale data from 1130 * previous tracing. 1131 */ 1132 skb = reset_per_cpu_data(data); 1133 consume_skb(skb); 1134 } 1135 1136 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1137 if (rc) { 1138 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1139 goto err_module_put; 1140 } 1141 1142 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1143 if (rc) { 1144 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1145 goto err_unregister_trace; 1146 } 1147 1148 return 0; 1149 1150 err_unregister_trace: 1151 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1152 err_module_put: 1153 for_each_possible_cpu(cpu) { 1154 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1155 struct sk_buff *skb; 1156 1157 del_timer_sync(&data->send_timer); 1158 cancel_work_sync(&data->dm_alert_work); 1159 while ((skb = __skb_dequeue(&data->drop_queue))) 1160 consume_skb(skb); 1161 } 1162 module_put(THIS_MODULE); 1163 return rc; 1164 } 1165 1166 static void net_dm_trace_off_set(void) 1167 { 1168 struct dm_hw_stat_delta *new_stat, *temp; 1169 const struct net_dm_alert_ops *ops; 1170 int cpu; 1171 1172 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1173 1174 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1175 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1176 1177 tracepoint_synchronize_unregister(); 1178 1179 /* Make sure we do not send notifications to user space after request 1180 * to stop tracing returns. 1181 */ 1182 for_each_possible_cpu(cpu) { 1183 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1184 struct sk_buff *skb; 1185 1186 del_timer_sync(&data->send_timer); 1187 cancel_work_sync(&data->dm_alert_work); 1188 while ((skb = __skb_dequeue(&data->drop_queue))) 1189 consume_skb(skb); 1190 } 1191 1192 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { 1193 if (new_stat->dev == NULL) { 1194 list_del_rcu(&new_stat->list); 1195 kfree_rcu(new_stat, rcu); 1196 } 1197 } 1198 1199 module_put(THIS_MODULE); 1200 } 1201 1202 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1203 { 1204 int rc = 0; 1205 1206 if (state == trace_state) { 1207 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1208 return -EAGAIN; 1209 } 1210 1211 switch (state) { 1212 case TRACE_ON: 1213 rc = net_dm_trace_on_set(extack); 1214 break; 1215 case TRACE_OFF: 1216 net_dm_trace_off_set(); 1217 break; 1218 default: 1219 rc = 1; 1220 break; 1221 } 1222 1223 if (!rc) 1224 trace_state = state; 1225 else 1226 rc = -EINPROGRESS; 1227 1228 return rc; 1229 } 1230 1231 static bool net_dm_is_monitoring(void) 1232 { 1233 return trace_state == TRACE_ON || monitor_hw; 1234 } 1235 1236 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1237 enum net_dm_alert_mode *p_alert_mode) 1238 { 1239 u8 val; 1240 1241 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1242 1243 switch (val) { 1244 case NET_DM_ALERT_MODE_SUMMARY: 1245 case NET_DM_ALERT_MODE_PACKET: 1246 *p_alert_mode = val; 1247 break; 1248 default: 1249 return -EINVAL; 1250 } 1251 1252 return 0; 1253 } 1254 1255 static int net_dm_alert_mode_set(struct genl_info *info) 1256 { 1257 struct netlink_ext_ack *extack = info->extack; 1258 enum net_dm_alert_mode alert_mode; 1259 int rc; 1260 1261 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1262 return 0; 1263 1264 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1265 if (rc) { 1266 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1267 return -EINVAL; 1268 } 1269 1270 net_dm_alert_mode = alert_mode; 1271 1272 return 0; 1273 } 1274 1275 static void net_dm_trunc_len_set(struct genl_info *info) 1276 { 1277 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1278 return; 1279 1280 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1281 } 1282 1283 static void net_dm_queue_len_set(struct genl_info *info) 1284 { 1285 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1286 return; 1287 1288 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1289 } 1290 1291 static int net_dm_cmd_config(struct sk_buff *skb, 1292 struct genl_info *info) 1293 { 1294 struct netlink_ext_ack *extack = info->extack; 1295 int rc; 1296 1297 if (net_dm_is_monitoring()) { 1298 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1299 return -EBUSY; 1300 } 1301 1302 rc = net_dm_alert_mode_set(info); 1303 if (rc) 1304 return rc; 1305 1306 net_dm_trunc_len_set(info); 1307 1308 net_dm_queue_len_set(info); 1309 1310 return 0; 1311 } 1312 1313 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1314 struct netlink_ext_ack *extack) 1315 { 1316 bool sw_set = false; 1317 int rc; 1318 1319 if (set_sw) { 1320 rc = set_all_monitor_traces(TRACE_ON, extack); 1321 if (rc) 1322 return rc; 1323 sw_set = true; 1324 } 1325 1326 if (set_hw) { 1327 rc = net_dm_hw_monitor_start(extack); 1328 if (rc) 1329 goto err_monitor_hw; 1330 } 1331 1332 return 0; 1333 1334 err_monitor_hw: 1335 if (sw_set) 1336 set_all_monitor_traces(TRACE_OFF, extack); 1337 return rc; 1338 } 1339 1340 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1341 struct netlink_ext_ack *extack) 1342 { 1343 if (set_hw) 1344 net_dm_hw_monitor_stop(extack); 1345 if (set_sw) 1346 set_all_monitor_traces(TRACE_OFF, extack); 1347 } 1348 1349 static int net_dm_cmd_trace(struct sk_buff *skb, 1350 struct genl_info *info) 1351 { 1352 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1353 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1354 struct netlink_ext_ack *extack = info->extack; 1355 1356 /* To maintain backward compatibility, we start / stop monitoring of 1357 * software drops if no flag is specified. 1358 */ 1359 if (!set_sw && !set_hw) 1360 set_sw = true; 1361 1362 switch (info->genlhdr->cmd) { 1363 case NET_DM_CMD_START: 1364 return net_dm_monitor_start(set_sw, set_hw, extack); 1365 case NET_DM_CMD_STOP: 1366 net_dm_monitor_stop(set_sw, set_hw, extack); 1367 return 0; 1368 } 1369 1370 return -EOPNOTSUPP; 1371 } 1372 1373 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1374 { 1375 void *hdr; 1376 1377 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1378 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1379 if (!hdr) 1380 return -EMSGSIZE; 1381 1382 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1383 goto nla_put_failure; 1384 1385 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1386 goto nla_put_failure; 1387 1388 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1389 goto nla_put_failure; 1390 1391 genlmsg_end(msg, hdr); 1392 1393 return 0; 1394 1395 nla_put_failure: 1396 genlmsg_cancel(msg, hdr); 1397 return -EMSGSIZE; 1398 } 1399 1400 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1401 { 1402 struct sk_buff *msg; 1403 int rc; 1404 1405 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1406 if (!msg) 1407 return -ENOMEM; 1408 1409 rc = net_dm_config_fill(msg, info); 1410 if (rc) 1411 goto free_msg; 1412 1413 return genlmsg_reply(msg, info); 1414 1415 free_msg: 1416 nlmsg_free(msg); 1417 return rc; 1418 } 1419 1420 static void net_dm_stats_read(struct net_dm_stats *stats) 1421 { 1422 int cpu; 1423 1424 memset(stats, 0, sizeof(*stats)); 1425 for_each_possible_cpu(cpu) { 1426 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1427 struct net_dm_stats *cpu_stats = &data->stats; 1428 unsigned int start; 1429 u64 dropped; 1430 1431 do { 1432 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1433 dropped = cpu_stats->dropped; 1434 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1435 1436 stats->dropped += dropped; 1437 } 1438 } 1439 1440 static int net_dm_stats_put(struct sk_buff *msg) 1441 { 1442 struct net_dm_stats stats; 1443 struct nlattr *attr; 1444 1445 net_dm_stats_read(&stats); 1446 1447 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1448 if (!attr) 1449 return -EMSGSIZE; 1450 1451 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1452 stats.dropped, NET_DM_ATTR_PAD)) 1453 goto nla_put_failure; 1454 1455 nla_nest_end(msg, attr); 1456 1457 return 0; 1458 1459 nla_put_failure: 1460 nla_nest_cancel(msg, attr); 1461 return -EMSGSIZE; 1462 } 1463 1464 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1465 { 1466 int cpu; 1467 1468 memset(stats, 0, sizeof(*stats)); 1469 for_each_possible_cpu(cpu) { 1470 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1471 struct net_dm_stats *cpu_stats = &hw_data->stats; 1472 unsigned int start; 1473 u64 dropped; 1474 1475 do { 1476 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1477 dropped = cpu_stats->dropped; 1478 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1479 1480 stats->dropped += dropped; 1481 } 1482 } 1483 1484 static int net_dm_hw_stats_put(struct sk_buff *msg) 1485 { 1486 struct net_dm_stats stats; 1487 struct nlattr *attr; 1488 1489 net_dm_hw_stats_read(&stats); 1490 1491 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1492 if (!attr) 1493 return -EMSGSIZE; 1494 1495 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1496 stats.dropped, NET_DM_ATTR_PAD)) 1497 goto nla_put_failure; 1498 1499 nla_nest_end(msg, attr); 1500 1501 return 0; 1502 1503 nla_put_failure: 1504 nla_nest_cancel(msg, attr); 1505 return -EMSGSIZE; 1506 } 1507 1508 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1509 { 1510 void *hdr; 1511 int rc; 1512 1513 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1514 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1515 if (!hdr) 1516 return -EMSGSIZE; 1517 1518 rc = net_dm_stats_put(msg); 1519 if (rc) 1520 goto nla_put_failure; 1521 1522 rc = net_dm_hw_stats_put(msg); 1523 if (rc) 1524 goto nla_put_failure; 1525 1526 genlmsg_end(msg, hdr); 1527 1528 return 0; 1529 1530 nla_put_failure: 1531 genlmsg_cancel(msg, hdr); 1532 return -EMSGSIZE; 1533 } 1534 1535 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1536 { 1537 struct sk_buff *msg; 1538 int rc; 1539 1540 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1541 if (!msg) 1542 return -ENOMEM; 1543 1544 rc = net_dm_stats_fill(msg, info); 1545 if (rc) 1546 goto free_msg; 1547 1548 return genlmsg_reply(msg, info); 1549 1550 free_msg: 1551 nlmsg_free(msg); 1552 return rc; 1553 } 1554 1555 static int dropmon_net_event(struct notifier_block *ev_block, 1556 unsigned long event, void *ptr) 1557 { 1558 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1559 struct dm_hw_stat_delta *new_stat = NULL; 1560 struct dm_hw_stat_delta *tmp; 1561 1562 switch (event) { 1563 case NETDEV_REGISTER: 1564 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); 1565 1566 if (!new_stat) 1567 goto out; 1568 1569 new_stat->dev = dev; 1570 new_stat->last_rx = jiffies; 1571 mutex_lock(&net_dm_mutex); 1572 list_add_rcu(&new_stat->list, &hw_stats_list); 1573 mutex_unlock(&net_dm_mutex); 1574 break; 1575 case NETDEV_UNREGISTER: 1576 mutex_lock(&net_dm_mutex); 1577 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { 1578 if (new_stat->dev == dev) { 1579 new_stat->dev = NULL; 1580 if (trace_state == TRACE_OFF) { 1581 list_del_rcu(&new_stat->list); 1582 kfree_rcu(new_stat, rcu); 1583 break; 1584 } 1585 } 1586 } 1587 mutex_unlock(&net_dm_mutex); 1588 break; 1589 } 1590 out: 1591 return NOTIFY_DONE; 1592 } 1593 1594 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1595 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1596 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1597 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1598 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1599 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1600 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1601 }; 1602 1603 static const struct genl_small_ops dropmon_ops[] = { 1604 { 1605 .cmd = NET_DM_CMD_CONFIG, 1606 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1607 .doit = net_dm_cmd_config, 1608 .flags = GENL_ADMIN_PERM, 1609 }, 1610 { 1611 .cmd = NET_DM_CMD_START, 1612 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1613 .doit = net_dm_cmd_trace, 1614 }, 1615 { 1616 .cmd = NET_DM_CMD_STOP, 1617 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1618 .doit = net_dm_cmd_trace, 1619 }, 1620 { 1621 .cmd = NET_DM_CMD_CONFIG_GET, 1622 .doit = net_dm_cmd_config_get, 1623 }, 1624 { 1625 .cmd = NET_DM_CMD_STATS_GET, 1626 .doit = net_dm_cmd_stats_get, 1627 }, 1628 }; 1629 1630 static int net_dm_nl_pre_doit(const struct genl_ops *ops, 1631 struct sk_buff *skb, struct genl_info *info) 1632 { 1633 mutex_lock(&net_dm_mutex); 1634 1635 return 0; 1636 } 1637 1638 static void net_dm_nl_post_doit(const struct genl_ops *ops, 1639 struct sk_buff *skb, struct genl_info *info) 1640 { 1641 mutex_unlock(&net_dm_mutex); 1642 } 1643 1644 static struct genl_family net_drop_monitor_family __ro_after_init = { 1645 .hdrsize = 0, 1646 .name = "NET_DM", 1647 .version = 2, 1648 .maxattr = NET_DM_ATTR_MAX, 1649 .policy = net_dm_nl_policy, 1650 .pre_doit = net_dm_nl_pre_doit, 1651 .post_doit = net_dm_nl_post_doit, 1652 .module = THIS_MODULE, 1653 .small_ops = dropmon_ops, 1654 .n_small_ops = ARRAY_SIZE(dropmon_ops), 1655 .mcgrps = dropmon_mcgrps, 1656 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1657 }; 1658 1659 static struct notifier_block dropmon_net_notifier = { 1660 .notifier_call = dropmon_net_event 1661 }; 1662 1663 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1664 { 1665 spin_lock_init(&data->lock); 1666 skb_queue_head_init(&data->drop_queue); 1667 u64_stats_init(&data->stats.syncp); 1668 } 1669 1670 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1671 { 1672 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1673 } 1674 1675 static void net_dm_cpu_data_init(int cpu) 1676 { 1677 struct per_cpu_dm_data *data; 1678 1679 data = &per_cpu(dm_cpu_data, cpu); 1680 __net_dm_cpu_data_init(data); 1681 } 1682 1683 static void net_dm_cpu_data_fini(int cpu) 1684 { 1685 struct per_cpu_dm_data *data; 1686 1687 data = &per_cpu(dm_cpu_data, cpu); 1688 /* At this point, we should have exclusive access 1689 * to this struct and can free the skb inside it. 1690 */ 1691 consume_skb(data->skb); 1692 __net_dm_cpu_data_fini(data); 1693 } 1694 1695 static void net_dm_hw_cpu_data_init(int cpu) 1696 { 1697 struct per_cpu_dm_data *hw_data; 1698 1699 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1700 __net_dm_cpu_data_init(hw_data); 1701 } 1702 1703 static void net_dm_hw_cpu_data_fini(int cpu) 1704 { 1705 struct per_cpu_dm_data *hw_data; 1706 1707 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1708 kfree(hw_data->hw_entries); 1709 __net_dm_cpu_data_fini(hw_data); 1710 } 1711 1712 static int __init init_net_drop_monitor(void) 1713 { 1714 int cpu, rc; 1715 1716 pr_info("Initializing network drop monitor service\n"); 1717 1718 if (sizeof(void *) > 8) { 1719 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1720 return -ENOSPC; 1721 } 1722 1723 rc = genl_register_family(&net_drop_monitor_family); 1724 if (rc) { 1725 pr_err("Could not create drop monitor netlink family\n"); 1726 return rc; 1727 } 1728 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1729 1730 rc = register_netdevice_notifier(&dropmon_net_notifier); 1731 if (rc < 0) { 1732 pr_crit("Failed to register netdevice notifier\n"); 1733 goto out_unreg; 1734 } 1735 1736 rc = 0; 1737 1738 for_each_possible_cpu(cpu) { 1739 net_dm_cpu_data_init(cpu); 1740 net_dm_hw_cpu_data_init(cpu); 1741 } 1742 1743 goto out; 1744 1745 out_unreg: 1746 genl_unregister_family(&net_drop_monitor_family); 1747 out: 1748 return rc; 1749 } 1750 1751 static void exit_net_drop_monitor(void) 1752 { 1753 int cpu; 1754 1755 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1756 1757 /* 1758 * Because of the module_get/put we do in the trace state change path 1759 * we are guaranteed not to have any current users when we get here 1760 */ 1761 1762 for_each_possible_cpu(cpu) { 1763 net_dm_hw_cpu_data_fini(cpu); 1764 net_dm_cpu_data_fini(cpu); 1765 } 1766 1767 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1768 } 1769 1770 module_init(init_net_drop_monitor); 1771 module_exit(exit_net_drop_monitor); 1772 1773 MODULE_LICENSE("GPL v2"); 1774 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1775 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1776 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1777