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