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 = kmemdup(hw_metadata->trap_group_name, 806 strlen(hw_metadata->trap_group_name) + 1, 807 GFP_ATOMIC | __GFP_ZERO); 808 if (!trap_group_name) 809 goto free_hw_metadata; 810 n_hw_metadata->trap_group_name = trap_group_name; 811 812 trap_name = kmemdup(hw_metadata->trap_name, 813 strlen(hw_metadata->trap_name) + 1, 814 GFP_ATOMIC | __GFP_ZERO); 815 if (!trap_name) 816 goto free_trap_group; 817 n_hw_metadata->trap_name = trap_name; 818 819 n_hw_metadata->input_dev = hw_metadata->input_dev; 820 if (n_hw_metadata->input_dev) 821 dev_hold(n_hw_metadata->input_dev); 822 823 return n_hw_metadata; 824 825 free_trap_group: 826 kfree(trap_group_name); 827 free_hw_metadata: 828 kfree(n_hw_metadata); 829 return NULL; 830 } 831 832 static void 833 net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata) 834 { 835 if (hw_metadata->input_dev) 836 dev_put(hw_metadata->input_dev); 837 kfree(hw_metadata->trap_name); 838 kfree(hw_metadata->trap_group_name); 839 kfree(hw_metadata); 840 } 841 842 static void net_dm_hw_packet_report(struct sk_buff *skb) 843 { 844 struct net_dm_hw_metadata *hw_metadata; 845 struct sk_buff *msg; 846 size_t payload_len; 847 int rc; 848 849 if (skb->data > skb_mac_header(skb)) 850 skb_push(skb, skb->data - skb_mac_header(skb)); 851 else 852 skb_pull(skb, skb_mac_header(skb) - skb->data); 853 854 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 855 if (net_dm_trunc_len) 856 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 857 858 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 859 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 860 GFP_KERNEL); 861 if (!msg) 862 goto out; 863 864 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 865 if (rc) { 866 nlmsg_free(msg); 867 goto out; 868 } 869 870 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 871 872 out: 873 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 874 consume_skb(skb); 875 } 876 877 static void net_dm_hw_packet_work(struct work_struct *work) 878 { 879 struct per_cpu_dm_data *hw_data; 880 struct sk_buff_head list; 881 struct sk_buff *skb; 882 unsigned long flags; 883 884 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 885 886 __skb_queue_head_init(&list); 887 888 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 889 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 890 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 891 892 while ((skb = __skb_dequeue(&list))) 893 net_dm_hw_packet_report(skb); 894 } 895 896 static void 897 net_dm_hw_packet_probe(struct sk_buff *skb, 898 const struct net_dm_hw_metadata *hw_metadata) 899 { 900 struct net_dm_hw_metadata *n_hw_metadata; 901 ktime_t tstamp = ktime_get_real(); 902 struct per_cpu_dm_data *hw_data; 903 struct sk_buff *nskb; 904 unsigned long flags; 905 906 if (!skb_mac_header_was_set(skb)) 907 return; 908 909 nskb = skb_clone(skb, GFP_ATOMIC); 910 if (!nskb) 911 return; 912 913 n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata); 914 if (!n_hw_metadata) 915 goto free; 916 917 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 918 nskb->tstamp = tstamp; 919 920 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 921 922 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 923 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 924 __skb_queue_tail(&hw_data->drop_queue, nskb); 925 else 926 goto unlock_free; 927 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 928 929 schedule_work(&hw_data->dm_alert_work); 930 931 return; 932 933 unlock_free: 934 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 935 u64_stats_update_begin(&hw_data->stats.syncp); 936 hw_data->stats.dropped++; 937 u64_stats_update_end(&hw_data->stats.syncp); 938 net_dm_hw_metadata_free(n_hw_metadata); 939 free: 940 consume_skb(nskb); 941 } 942 943 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 944 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 945 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 946 .work_item_func = net_dm_packet_work, 947 .hw_work_item_func = net_dm_hw_packet_work, 948 .hw_probe = net_dm_hw_packet_probe, 949 }; 950 951 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 952 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 953 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 954 }; 955 956 void net_dm_hw_report(struct sk_buff *skb, 957 const struct net_dm_hw_metadata *hw_metadata) 958 { 959 rcu_read_lock(); 960 961 if (!monitor_hw) 962 goto out; 963 964 net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata); 965 966 out: 967 rcu_read_unlock(); 968 } 969 EXPORT_SYMBOL_GPL(net_dm_hw_report); 970 971 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 972 { 973 const struct net_dm_alert_ops *ops; 974 int cpu; 975 976 if (monitor_hw) { 977 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 978 return -EAGAIN; 979 } 980 981 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 982 983 if (!try_module_get(THIS_MODULE)) { 984 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 985 return -ENODEV; 986 } 987 988 for_each_possible_cpu(cpu) { 989 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 990 struct net_dm_hw_entries *hw_entries; 991 992 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 993 timer_setup(&hw_data->send_timer, sched_send_work, 0); 994 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 995 kfree(hw_entries); 996 } 997 998 monitor_hw = true; 999 1000 return 0; 1001 } 1002 1003 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1004 { 1005 int cpu; 1006 1007 if (!monitor_hw) 1008 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1009 1010 monitor_hw = false; 1011 1012 /* After this call returns we are guaranteed that no CPU is processing 1013 * any hardware drops. 1014 */ 1015 synchronize_rcu(); 1016 1017 for_each_possible_cpu(cpu) { 1018 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1019 struct sk_buff *skb; 1020 1021 del_timer_sync(&hw_data->send_timer); 1022 cancel_work_sync(&hw_data->dm_alert_work); 1023 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1024 struct net_dm_hw_metadata *hw_metadata; 1025 1026 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1027 net_dm_hw_metadata_free(hw_metadata); 1028 consume_skb(skb); 1029 } 1030 } 1031 1032 module_put(THIS_MODULE); 1033 } 1034 1035 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1036 { 1037 const struct net_dm_alert_ops *ops; 1038 int cpu, rc; 1039 1040 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1041 1042 if (!try_module_get(THIS_MODULE)) { 1043 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1044 return -ENODEV; 1045 } 1046 1047 for_each_possible_cpu(cpu) { 1048 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1049 struct sk_buff *skb; 1050 1051 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1052 timer_setup(&data->send_timer, sched_send_work, 0); 1053 /* Allocate a new per-CPU skb for the summary alert message and 1054 * free the old one which might contain stale data from 1055 * previous tracing. 1056 */ 1057 skb = reset_per_cpu_data(data); 1058 consume_skb(skb); 1059 } 1060 1061 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1062 if (rc) { 1063 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1064 goto err_module_put; 1065 } 1066 1067 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1068 if (rc) { 1069 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1070 goto err_unregister_trace; 1071 } 1072 1073 return 0; 1074 1075 err_unregister_trace: 1076 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1077 err_module_put: 1078 module_put(THIS_MODULE); 1079 return rc; 1080 } 1081 1082 static void net_dm_trace_off_set(void) 1083 { 1084 struct dm_hw_stat_delta *new_stat, *temp; 1085 const struct net_dm_alert_ops *ops; 1086 int cpu; 1087 1088 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1089 1090 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1091 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1092 1093 tracepoint_synchronize_unregister(); 1094 1095 /* Make sure we do not send notifications to user space after request 1096 * to stop tracing returns. 1097 */ 1098 for_each_possible_cpu(cpu) { 1099 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1100 struct sk_buff *skb; 1101 1102 del_timer_sync(&data->send_timer); 1103 cancel_work_sync(&data->dm_alert_work); 1104 while ((skb = __skb_dequeue(&data->drop_queue))) 1105 consume_skb(skb); 1106 } 1107 1108 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { 1109 if (new_stat->dev == NULL) { 1110 list_del_rcu(&new_stat->list); 1111 kfree_rcu(new_stat, rcu); 1112 } 1113 } 1114 1115 module_put(THIS_MODULE); 1116 } 1117 1118 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1119 { 1120 int rc = 0; 1121 1122 if (state == trace_state) { 1123 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1124 return -EAGAIN; 1125 } 1126 1127 switch (state) { 1128 case TRACE_ON: 1129 rc = net_dm_trace_on_set(extack); 1130 break; 1131 case TRACE_OFF: 1132 net_dm_trace_off_set(); 1133 break; 1134 default: 1135 rc = 1; 1136 break; 1137 } 1138 1139 if (!rc) 1140 trace_state = state; 1141 else 1142 rc = -EINPROGRESS; 1143 1144 return rc; 1145 } 1146 1147 static bool net_dm_is_monitoring(void) 1148 { 1149 return trace_state == TRACE_ON || monitor_hw; 1150 } 1151 1152 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1153 enum net_dm_alert_mode *p_alert_mode) 1154 { 1155 u8 val; 1156 1157 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1158 1159 switch (val) { 1160 case NET_DM_ALERT_MODE_SUMMARY: /* fall-through */ 1161 case NET_DM_ALERT_MODE_PACKET: 1162 *p_alert_mode = val; 1163 break; 1164 default: 1165 return -EINVAL; 1166 } 1167 1168 return 0; 1169 } 1170 1171 static int net_dm_alert_mode_set(struct genl_info *info) 1172 { 1173 struct netlink_ext_ack *extack = info->extack; 1174 enum net_dm_alert_mode alert_mode; 1175 int rc; 1176 1177 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1178 return 0; 1179 1180 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1181 if (rc) { 1182 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1183 return -EINVAL; 1184 } 1185 1186 net_dm_alert_mode = alert_mode; 1187 1188 return 0; 1189 } 1190 1191 static void net_dm_trunc_len_set(struct genl_info *info) 1192 { 1193 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1194 return; 1195 1196 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1197 } 1198 1199 static void net_dm_queue_len_set(struct genl_info *info) 1200 { 1201 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1202 return; 1203 1204 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1205 } 1206 1207 static int net_dm_cmd_config(struct sk_buff *skb, 1208 struct genl_info *info) 1209 { 1210 struct netlink_ext_ack *extack = info->extack; 1211 int rc; 1212 1213 if (net_dm_is_monitoring()) { 1214 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1215 return -EBUSY; 1216 } 1217 1218 rc = net_dm_alert_mode_set(info); 1219 if (rc) 1220 return rc; 1221 1222 net_dm_trunc_len_set(info); 1223 1224 net_dm_queue_len_set(info); 1225 1226 return 0; 1227 } 1228 1229 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1230 struct netlink_ext_ack *extack) 1231 { 1232 bool sw_set = false; 1233 int rc; 1234 1235 if (set_sw) { 1236 rc = set_all_monitor_traces(TRACE_ON, extack); 1237 if (rc) 1238 return rc; 1239 sw_set = true; 1240 } 1241 1242 if (set_hw) { 1243 rc = net_dm_hw_monitor_start(extack); 1244 if (rc) 1245 goto err_monitor_hw; 1246 } 1247 1248 return 0; 1249 1250 err_monitor_hw: 1251 if (sw_set) 1252 set_all_monitor_traces(TRACE_OFF, extack); 1253 return rc; 1254 } 1255 1256 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1257 struct netlink_ext_ack *extack) 1258 { 1259 if (set_hw) 1260 net_dm_hw_monitor_stop(extack); 1261 if (set_sw) 1262 set_all_monitor_traces(TRACE_OFF, extack); 1263 } 1264 1265 static int net_dm_cmd_trace(struct sk_buff *skb, 1266 struct genl_info *info) 1267 { 1268 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1269 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1270 struct netlink_ext_ack *extack = info->extack; 1271 1272 /* To maintain backward compatibility, we start / stop monitoring of 1273 * software drops if no flag is specified. 1274 */ 1275 if (!set_sw && !set_hw) 1276 set_sw = true; 1277 1278 switch (info->genlhdr->cmd) { 1279 case NET_DM_CMD_START: 1280 return net_dm_monitor_start(set_sw, set_hw, extack); 1281 case NET_DM_CMD_STOP: 1282 net_dm_monitor_stop(set_sw, set_hw, extack); 1283 return 0; 1284 } 1285 1286 return -EOPNOTSUPP; 1287 } 1288 1289 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1290 { 1291 void *hdr; 1292 1293 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1294 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1295 if (!hdr) 1296 return -EMSGSIZE; 1297 1298 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1299 goto nla_put_failure; 1300 1301 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1302 goto nla_put_failure; 1303 1304 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1305 goto nla_put_failure; 1306 1307 genlmsg_end(msg, hdr); 1308 1309 return 0; 1310 1311 nla_put_failure: 1312 genlmsg_cancel(msg, hdr); 1313 return -EMSGSIZE; 1314 } 1315 1316 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1317 { 1318 struct sk_buff *msg; 1319 int rc; 1320 1321 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1322 if (!msg) 1323 return -ENOMEM; 1324 1325 rc = net_dm_config_fill(msg, info); 1326 if (rc) 1327 goto free_msg; 1328 1329 return genlmsg_reply(msg, info); 1330 1331 free_msg: 1332 nlmsg_free(msg); 1333 return rc; 1334 } 1335 1336 static void net_dm_stats_read(struct net_dm_stats *stats) 1337 { 1338 int cpu; 1339 1340 memset(stats, 0, sizeof(*stats)); 1341 for_each_possible_cpu(cpu) { 1342 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1343 struct net_dm_stats *cpu_stats = &data->stats; 1344 unsigned int start; 1345 u64 dropped; 1346 1347 do { 1348 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1349 dropped = cpu_stats->dropped; 1350 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1351 1352 stats->dropped += dropped; 1353 } 1354 } 1355 1356 static int net_dm_stats_put(struct sk_buff *msg) 1357 { 1358 struct net_dm_stats stats; 1359 struct nlattr *attr; 1360 1361 net_dm_stats_read(&stats); 1362 1363 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1364 if (!attr) 1365 return -EMSGSIZE; 1366 1367 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1368 stats.dropped, NET_DM_ATTR_PAD)) 1369 goto nla_put_failure; 1370 1371 nla_nest_end(msg, attr); 1372 1373 return 0; 1374 1375 nla_put_failure: 1376 nla_nest_cancel(msg, attr); 1377 return -EMSGSIZE; 1378 } 1379 1380 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1381 { 1382 int cpu; 1383 1384 memset(stats, 0, sizeof(*stats)); 1385 for_each_possible_cpu(cpu) { 1386 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1387 struct net_dm_stats *cpu_stats = &hw_data->stats; 1388 unsigned int start; 1389 u64 dropped; 1390 1391 do { 1392 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1393 dropped = cpu_stats->dropped; 1394 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1395 1396 stats->dropped += dropped; 1397 } 1398 } 1399 1400 static int net_dm_hw_stats_put(struct sk_buff *msg) 1401 { 1402 struct net_dm_stats stats; 1403 struct nlattr *attr; 1404 1405 net_dm_hw_stats_read(&stats); 1406 1407 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1408 if (!attr) 1409 return -EMSGSIZE; 1410 1411 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1412 stats.dropped, NET_DM_ATTR_PAD)) 1413 goto nla_put_failure; 1414 1415 nla_nest_end(msg, attr); 1416 1417 return 0; 1418 1419 nla_put_failure: 1420 nla_nest_cancel(msg, attr); 1421 return -EMSGSIZE; 1422 } 1423 1424 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1425 { 1426 void *hdr; 1427 int rc; 1428 1429 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1430 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1431 if (!hdr) 1432 return -EMSGSIZE; 1433 1434 rc = net_dm_stats_put(msg); 1435 if (rc) 1436 goto nla_put_failure; 1437 1438 rc = net_dm_hw_stats_put(msg); 1439 if (rc) 1440 goto nla_put_failure; 1441 1442 genlmsg_end(msg, hdr); 1443 1444 return 0; 1445 1446 nla_put_failure: 1447 genlmsg_cancel(msg, hdr); 1448 return -EMSGSIZE; 1449 } 1450 1451 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1452 { 1453 struct sk_buff *msg; 1454 int rc; 1455 1456 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1457 if (!msg) 1458 return -ENOMEM; 1459 1460 rc = net_dm_stats_fill(msg, info); 1461 if (rc) 1462 goto free_msg; 1463 1464 return genlmsg_reply(msg, info); 1465 1466 free_msg: 1467 nlmsg_free(msg); 1468 return rc; 1469 } 1470 1471 static int dropmon_net_event(struct notifier_block *ev_block, 1472 unsigned long event, void *ptr) 1473 { 1474 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1475 struct dm_hw_stat_delta *new_stat = NULL; 1476 struct dm_hw_stat_delta *tmp; 1477 1478 switch (event) { 1479 case NETDEV_REGISTER: 1480 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); 1481 1482 if (!new_stat) 1483 goto out; 1484 1485 new_stat->dev = dev; 1486 new_stat->last_rx = jiffies; 1487 mutex_lock(&net_dm_mutex); 1488 list_add_rcu(&new_stat->list, &hw_stats_list); 1489 mutex_unlock(&net_dm_mutex); 1490 break; 1491 case NETDEV_UNREGISTER: 1492 mutex_lock(&net_dm_mutex); 1493 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { 1494 if (new_stat->dev == dev) { 1495 new_stat->dev = NULL; 1496 if (trace_state == TRACE_OFF) { 1497 list_del_rcu(&new_stat->list); 1498 kfree_rcu(new_stat, rcu); 1499 break; 1500 } 1501 } 1502 } 1503 mutex_unlock(&net_dm_mutex); 1504 break; 1505 } 1506 out: 1507 return NOTIFY_DONE; 1508 } 1509 1510 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1511 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1512 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1513 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1514 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1515 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1516 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1517 }; 1518 1519 static const struct genl_ops dropmon_ops[] = { 1520 { 1521 .cmd = NET_DM_CMD_CONFIG, 1522 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1523 .doit = net_dm_cmd_config, 1524 .flags = GENL_ADMIN_PERM, 1525 }, 1526 { 1527 .cmd = NET_DM_CMD_START, 1528 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1529 .doit = net_dm_cmd_trace, 1530 }, 1531 { 1532 .cmd = NET_DM_CMD_STOP, 1533 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1534 .doit = net_dm_cmd_trace, 1535 }, 1536 { 1537 .cmd = NET_DM_CMD_CONFIG_GET, 1538 .doit = net_dm_cmd_config_get, 1539 }, 1540 { 1541 .cmd = NET_DM_CMD_STATS_GET, 1542 .doit = net_dm_cmd_stats_get, 1543 }, 1544 }; 1545 1546 static int net_dm_nl_pre_doit(const struct genl_ops *ops, 1547 struct sk_buff *skb, struct genl_info *info) 1548 { 1549 mutex_lock(&net_dm_mutex); 1550 1551 return 0; 1552 } 1553 1554 static void net_dm_nl_post_doit(const struct genl_ops *ops, 1555 struct sk_buff *skb, struct genl_info *info) 1556 { 1557 mutex_unlock(&net_dm_mutex); 1558 } 1559 1560 static struct genl_family net_drop_monitor_family __ro_after_init = { 1561 .hdrsize = 0, 1562 .name = "NET_DM", 1563 .version = 2, 1564 .maxattr = NET_DM_ATTR_MAX, 1565 .policy = net_dm_nl_policy, 1566 .pre_doit = net_dm_nl_pre_doit, 1567 .post_doit = net_dm_nl_post_doit, 1568 .module = THIS_MODULE, 1569 .ops = dropmon_ops, 1570 .n_ops = ARRAY_SIZE(dropmon_ops), 1571 .mcgrps = dropmon_mcgrps, 1572 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1573 }; 1574 1575 static struct notifier_block dropmon_net_notifier = { 1576 .notifier_call = dropmon_net_event 1577 }; 1578 1579 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1580 { 1581 spin_lock_init(&data->lock); 1582 skb_queue_head_init(&data->drop_queue); 1583 u64_stats_init(&data->stats.syncp); 1584 } 1585 1586 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1587 { 1588 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1589 } 1590 1591 static void net_dm_cpu_data_init(int cpu) 1592 { 1593 struct per_cpu_dm_data *data; 1594 1595 data = &per_cpu(dm_cpu_data, cpu); 1596 __net_dm_cpu_data_init(data); 1597 } 1598 1599 static void net_dm_cpu_data_fini(int cpu) 1600 { 1601 struct per_cpu_dm_data *data; 1602 1603 data = &per_cpu(dm_cpu_data, cpu); 1604 /* At this point, we should have exclusive access 1605 * to this struct and can free the skb inside it. 1606 */ 1607 consume_skb(data->skb); 1608 __net_dm_cpu_data_fini(data); 1609 } 1610 1611 static void net_dm_hw_cpu_data_init(int cpu) 1612 { 1613 struct per_cpu_dm_data *hw_data; 1614 1615 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1616 __net_dm_cpu_data_init(hw_data); 1617 } 1618 1619 static void net_dm_hw_cpu_data_fini(int cpu) 1620 { 1621 struct per_cpu_dm_data *hw_data; 1622 1623 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1624 kfree(hw_data->hw_entries); 1625 __net_dm_cpu_data_fini(hw_data); 1626 } 1627 1628 static int __init init_net_drop_monitor(void) 1629 { 1630 int cpu, rc; 1631 1632 pr_info("Initializing network drop monitor service\n"); 1633 1634 if (sizeof(void *) > 8) { 1635 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1636 return -ENOSPC; 1637 } 1638 1639 rc = genl_register_family(&net_drop_monitor_family); 1640 if (rc) { 1641 pr_err("Could not create drop monitor netlink family\n"); 1642 return rc; 1643 } 1644 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1645 1646 rc = register_netdevice_notifier(&dropmon_net_notifier); 1647 if (rc < 0) { 1648 pr_crit("Failed to register netdevice notifier\n"); 1649 goto out_unreg; 1650 } 1651 1652 rc = 0; 1653 1654 for_each_possible_cpu(cpu) { 1655 net_dm_cpu_data_init(cpu); 1656 net_dm_hw_cpu_data_init(cpu); 1657 } 1658 1659 goto out; 1660 1661 out_unreg: 1662 genl_unregister_family(&net_drop_monitor_family); 1663 out: 1664 return rc; 1665 } 1666 1667 static void exit_net_drop_monitor(void) 1668 { 1669 int cpu; 1670 1671 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1672 1673 /* 1674 * Because of the module_get/put we do in the trace state change path 1675 * we are guarnateed not to have any current users when we get here 1676 */ 1677 1678 for_each_possible_cpu(cpu) { 1679 net_dm_hw_cpu_data_fini(cpu); 1680 net_dm_cpu_data_fini(cpu); 1681 } 1682 1683 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1684 } 1685 1686 module_init(init_net_drop_monitor); 1687 module_exit(exit_net_drop_monitor); 1688 1689 MODULE_LICENSE("GPL v2"); 1690 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1691 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1692