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 nskb = skb_clone(skb, GFP_ATOMIC); 491 if (!nskb) 492 return; 493 494 NET_DM_SKB_CB(nskb)->pc = location; 495 /* Override the timestamp because we care about the time when the 496 * packet was dropped. 497 */ 498 nskb->tstamp = tstamp; 499 500 data = this_cpu_ptr(&dm_cpu_data); 501 502 spin_lock_irqsave(&data->drop_queue.lock, flags); 503 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 504 __skb_queue_tail(&data->drop_queue, nskb); 505 else 506 goto unlock_free; 507 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 508 509 schedule_work(&data->dm_alert_work); 510 511 return; 512 513 unlock_free: 514 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 515 u64_stats_update_begin(&data->stats.syncp); 516 data->stats.dropped++; 517 u64_stats_update_end(&data->stats.syncp); 518 consume_skb(nskb); 519 } 520 521 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 522 struct napi_struct *napi, 523 int work, int budget) 524 { 525 } 526 527 static size_t net_dm_in_port_size(void) 528 { 529 /* NET_DM_ATTR_IN_PORT nest */ 530 return nla_total_size(0) + 531 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 532 nla_total_size(sizeof(u32)) + 533 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 534 nla_total_size(IFNAMSIZ + 1); 535 } 536 537 #define NET_DM_MAX_SYMBOL_LEN 40 538 539 static size_t net_dm_packet_report_size(size_t payload_len) 540 { 541 size_t size; 542 543 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 544 545 return NLMSG_ALIGN(size) + 546 /* NET_DM_ATTR_ORIGIN */ 547 nla_total_size(sizeof(u16)) + 548 /* NET_DM_ATTR_PC */ 549 nla_total_size(sizeof(u64)) + 550 /* NET_DM_ATTR_SYMBOL */ 551 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 552 /* NET_DM_ATTR_IN_PORT */ 553 net_dm_in_port_size() + 554 /* NET_DM_ATTR_TIMESTAMP */ 555 nla_total_size(sizeof(u64)) + 556 /* NET_DM_ATTR_ORIG_LEN */ 557 nla_total_size(sizeof(u32)) + 558 /* NET_DM_ATTR_PROTO */ 559 nla_total_size(sizeof(u16)) + 560 /* NET_DM_ATTR_PAYLOAD */ 561 nla_total_size(payload_len); 562 } 563 564 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 565 const char *name) 566 { 567 struct nlattr *attr; 568 569 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 570 if (!attr) 571 return -EMSGSIZE; 572 573 if (ifindex && 574 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 575 goto nla_put_failure; 576 577 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 578 goto nla_put_failure; 579 580 nla_nest_end(msg, attr); 581 582 return 0; 583 584 nla_put_failure: 585 nla_nest_cancel(msg, attr); 586 return -EMSGSIZE; 587 } 588 589 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 590 size_t payload_len) 591 { 592 u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; 593 char buf[NET_DM_MAX_SYMBOL_LEN]; 594 struct nlattr *attr; 595 void *hdr; 596 int rc; 597 598 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 599 NET_DM_CMD_PACKET_ALERT); 600 if (!hdr) 601 return -EMSGSIZE; 602 603 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 604 goto nla_put_failure; 605 606 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) 607 goto nla_put_failure; 608 609 snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); 610 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 611 goto nla_put_failure; 612 613 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 614 if (rc) 615 goto nla_put_failure; 616 617 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 618 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 619 goto nla_put_failure; 620 621 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 622 goto nla_put_failure; 623 624 if (!payload_len) 625 goto out; 626 627 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 628 goto nla_put_failure; 629 630 attr = skb_put(msg, nla_total_size(payload_len)); 631 attr->nla_type = NET_DM_ATTR_PAYLOAD; 632 attr->nla_len = nla_attr_size(payload_len); 633 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 634 goto nla_put_failure; 635 636 out: 637 genlmsg_end(msg, hdr); 638 639 return 0; 640 641 nla_put_failure: 642 genlmsg_cancel(msg, hdr); 643 return -EMSGSIZE; 644 } 645 646 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 647 648 static void net_dm_packet_report(struct sk_buff *skb) 649 { 650 struct sk_buff *msg; 651 size_t payload_len; 652 int rc; 653 654 /* Make sure we start copying the packet from the MAC header */ 655 if (skb->data > skb_mac_header(skb)) 656 skb_push(skb, skb->data - skb_mac_header(skb)); 657 else 658 skb_pull(skb, skb_mac_header(skb) - skb->data); 659 660 /* Ensure packet fits inside a single netlink attribute */ 661 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 662 if (net_dm_trunc_len) 663 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 664 665 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 666 if (!msg) 667 goto out; 668 669 rc = net_dm_packet_report_fill(msg, skb, payload_len); 670 if (rc) { 671 nlmsg_free(msg); 672 goto out; 673 } 674 675 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 676 677 out: 678 consume_skb(skb); 679 } 680 681 static void net_dm_packet_work(struct work_struct *work) 682 { 683 struct per_cpu_dm_data *data; 684 struct sk_buff_head list; 685 struct sk_buff *skb; 686 unsigned long flags; 687 688 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 689 690 __skb_queue_head_init(&list); 691 692 spin_lock_irqsave(&data->drop_queue.lock, flags); 693 skb_queue_splice_tail_init(&data->drop_queue, &list); 694 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 695 696 while ((skb = __skb_dequeue(&list))) 697 net_dm_packet_report(skb); 698 } 699 700 static size_t 701 net_dm_hw_packet_report_size(size_t payload_len, 702 const struct net_dm_hw_metadata *hw_metadata) 703 { 704 size_t size; 705 706 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 707 708 return NLMSG_ALIGN(size) + 709 /* NET_DM_ATTR_ORIGIN */ 710 nla_total_size(sizeof(u16)) + 711 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 712 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 713 /* NET_DM_ATTR_HW_TRAP_NAME */ 714 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 715 /* NET_DM_ATTR_IN_PORT */ 716 net_dm_in_port_size() + 717 /* NET_DM_ATTR_TIMESTAMP */ 718 nla_total_size(sizeof(u64)) + 719 /* NET_DM_ATTR_ORIG_LEN */ 720 nla_total_size(sizeof(u32)) + 721 /* NET_DM_ATTR_PROTO */ 722 nla_total_size(sizeof(u16)) + 723 /* NET_DM_ATTR_PAYLOAD */ 724 nla_total_size(payload_len); 725 } 726 727 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 728 struct sk_buff *skb, size_t payload_len) 729 { 730 struct net_dm_hw_metadata *hw_metadata; 731 struct nlattr *attr; 732 void *hdr; 733 734 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 735 736 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 737 NET_DM_CMD_PACKET_ALERT); 738 if (!hdr) 739 return -EMSGSIZE; 740 741 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 742 goto nla_put_failure; 743 744 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 745 hw_metadata->trap_group_name)) 746 goto nla_put_failure; 747 748 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 749 hw_metadata->trap_name)) 750 goto nla_put_failure; 751 752 if (hw_metadata->input_dev) { 753 struct net_device *dev = hw_metadata->input_dev; 754 int rc; 755 756 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 757 dev->name); 758 if (rc) 759 goto nla_put_failure; 760 } 761 762 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 763 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 764 goto nla_put_failure; 765 766 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 767 goto nla_put_failure; 768 769 if (!payload_len) 770 goto out; 771 772 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 773 goto nla_put_failure; 774 775 attr = skb_put(msg, nla_total_size(payload_len)); 776 attr->nla_type = NET_DM_ATTR_PAYLOAD; 777 attr->nla_len = nla_attr_size(payload_len); 778 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 779 goto nla_put_failure; 780 781 out: 782 genlmsg_end(msg, hdr); 783 784 return 0; 785 786 nla_put_failure: 787 genlmsg_cancel(msg, hdr); 788 return -EMSGSIZE; 789 } 790 791 static struct net_dm_hw_metadata * 792 net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata) 793 { 794 struct net_dm_hw_metadata *n_hw_metadata; 795 const char *trap_group_name; 796 const char *trap_name; 797 798 n_hw_metadata = kmalloc(sizeof(*hw_metadata), GFP_ATOMIC); 799 if (!n_hw_metadata) 800 return NULL; 801 802 trap_group_name = kmemdup(hw_metadata->trap_group_name, 803 strlen(hw_metadata->trap_group_name) + 1, 804 GFP_ATOMIC | __GFP_ZERO); 805 if (!trap_group_name) 806 goto free_hw_metadata; 807 n_hw_metadata->trap_group_name = trap_group_name; 808 809 trap_name = kmemdup(hw_metadata->trap_name, 810 strlen(hw_metadata->trap_name) + 1, 811 GFP_ATOMIC | __GFP_ZERO); 812 if (!trap_name) 813 goto free_trap_group; 814 n_hw_metadata->trap_name = trap_name; 815 816 n_hw_metadata->input_dev = hw_metadata->input_dev; 817 if (n_hw_metadata->input_dev) 818 dev_hold(n_hw_metadata->input_dev); 819 820 return n_hw_metadata; 821 822 free_trap_group: 823 kfree(trap_group_name); 824 free_hw_metadata: 825 kfree(n_hw_metadata); 826 return NULL; 827 } 828 829 static void 830 net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata) 831 { 832 if (hw_metadata->input_dev) 833 dev_put(hw_metadata->input_dev); 834 kfree(hw_metadata->trap_name); 835 kfree(hw_metadata->trap_group_name); 836 kfree(hw_metadata); 837 } 838 839 static void net_dm_hw_packet_report(struct sk_buff *skb) 840 { 841 struct net_dm_hw_metadata *hw_metadata; 842 struct sk_buff *msg; 843 size_t payload_len; 844 int rc; 845 846 if (skb->data > skb_mac_header(skb)) 847 skb_push(skb, skb->data - skb_mac_header(skb)); 848 else 849 skb_pull(skb, skb_mac_header(skb) - skb->data); 850 851 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 852 if (net_dm_trunc_len) 853 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 854 855 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 856 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 857 GFP_KERNEL); 858 if (!msg) 859 goto out; 860 861 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 862 if (rc) { 863 nlmsg_free(msg); 864 goto out; 865 } 866 867 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 868 869 out: 870 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 871 consume_skb(skb); 872 } 873 874 static void net_dm_hw_packet_work(struct work_struct *work) 875 { 876 struct per_cpu_dm_data *hw_data; 877 struct sk_buff_head list; 878 struct sk_buff *skb; 879 unsigned long flags; 880 881 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 882 883 __skb_queue_head_init(&list); 884 885 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 886 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 887 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 888 889 while ((skb = __skb_dequeue(&list))) 890 net_dm_hw_packet_report(skb); 891 } 892 893 static void 894 net_dm_hw_packet_probe(struct sk_buff *skb, 895 const struct net_dm_hw_metadata *hw_metadata) 896 { 897 struct net_dm_hw_metadata *n_hw_metadata; 898 ktime_t tstamp = ktime_get_real(); 899 struct per_cpu_dm_data *hw_data; 900 struct sk_buff *nskb; 901 unsigned long flags; 902 903 nskb = skb_clone(skb, GFP_ATOMIC); 904 if (!nskb) 905 return; 906 907 n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata); 908 if (!n_hw_metadata) 909 goto free; 910 911 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 912 nskb->tstamp = tstamp; 913 914 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 915 916 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 917 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 918 __skb_queue_tail(&hw_data->drop_queue, nskb); 919 else 920 goto unlock_free; 921 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 922 923 schedule_work(&hw_data->dm_alert_work); 924 925 return; 926 927 unlock_free: 928 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 929 u64_stats_update_begin(&hw_data->stats.syncp); 930 hw_data->stats.dropped++; 931 u64_stats_update_end(&hw_data->stats.syncp); 932 net_dm_hw_metadata_free(n_hw_metadata); 933 free: 934 consume_skb(nskb); 935 } 936 937 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 938 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 939 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 940 .work_item_func = net_dm_packet_work, 941 .hw_work_item_func = net_dm_hw_packet_work, 942 .hw_probe = net_dm_hw_packet_probe, 943 }; 944 945 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 946 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 947 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 948 }; 949 950 void net_dm_hw_report(struct sk_buff *skb, 951 const struct net_dm_hw_metadata *hw_metadata) 952 { 953 rcu_read_lock(); 954 955 if (!monitor_hw) 956 goto out; 957 958 net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata); 959 960 out: 961 rcu_read_unlock(); 962 } 963 EXPORT_SYMBOL_GPL(net_dm_hw_report); 964 965 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 966 { 967 const struct net_dm_alert_ops *ops; 968 int cpu; 969 970 if (monitor_hw) { 971 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 972 return -EAGAIN; 973 } 974 975 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 976 977 if (!try_module_get(THIS_MODULE)) { 978 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 979 return -ENODEV; 980 } 981 982 for_each_possible_cpu(cpu) { 983 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 984 struct net_dm_hw_entries *hw_entries; 985 986 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 987 timer_setup(&hw_data->send_timer, sched_send_work, 0); 988 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 989 kfree(hw_entries); 990 } 991 992 monitor_hw = true; 993 994 return 0; 995 } 996 997 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 998 { 999 int cpu; 1000 1001 if (!monitor_hw) 1002 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1003 1004 monitor_hw = false; 1005 1006 /* After this call returns we are guaranteed that no CPU is processing 1007 * any hardware drops. 1008 */ 1009 synchronize_rcu(); 1010 1011 for_each_possible_cpu(cpu) { 1012 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1013 struct sk_buff *skb; 1014 1015 del_timer_sync(&hw_data->send_timer); 1016 cancel_work_sync(&hw_data->dm_alert_work); 1017 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1018 struct net_dm_hw_metadata *hw_metadata; 1019 1020 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1021 net_dm_hw_metadata_free(hw_metadata); 1022 consume_skb(skb); 1023 } 1024 } 1025 1026 module_put(THIS_MODULE); 1027 } 1028 1029 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1030 { 1031 const struct net_dm_alert_ops *ops; 1032 int cpu, rc; 1033 1034 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1035 1036 if (!try_module_get(THIS_MODULE)) { 1037 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1038 return -ENODEV; 1039 } 1040 1041 for_each_possible_cpu(cpu) { 1042 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1043 struct sk_buff *skb; 1044 1045 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1046 timer_setup(&data->send_timer, sched_send_work, 0); 1047 /* Allocate a new per-CPU skb for the summary alert message and 1048 * free the old one which might contain stale data from 1049 * previous tracing. 1050 */ 1051 skb = reset_per_cpu_data(data); 1052 consume_skb(skb); 1053 } 1054 1055 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1056 if (rc) { 1057 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1058 goto err_module_put; 1059 } 1060 1061 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1062 if (rc) { 1063 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1064 goto err_unregister_trace; 1065 } 1066 1067 return 0; 1068 1069 err_unregister_trace: 1070 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1071 err_module_put: 1072 module_put(THIS_MODULE); 1073 return rc; 1074 } 1075 1076 static void net_dm_trace_off_set(void) 1077 { 1078 struct dm_hw_stat_delta *new_stat, *temp; 1079 const struct net_dm_alert_ops *ops; 1080 int cpu; 1081 1082 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1083 1084 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1085 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1086 1087 tracepoint_synchronize_unregister(); 1088 1089 /* Make sure we do not send notifications to user space after request 1090 * to stop tracing returns. 1091 */ 1092 for_each_possible_cpu(cpu) { 1093 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1094 struct sk_buff *skb; 1095 1096 del_timer_sync(&data->send_timer); 1097 cancel_work_sync(&data->dm_alert_work); 1098 while ((skb = __skb_dequeue(&data->drop_queue))) 1099 consume_skb(skb); 1100 } 1101 1102 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { 1103 if (new_stat->dev == NULL) { 1104 list_del_rcu(&new_stat->list); 1105 kfree_rcu(new_stat, rcu); 1106 } 1107 } 1108 1109 module_put(THIS_MODULE); 1110 } 1111 1112 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1113 { 1114 int rc = 0; 1115 1116 if (state == trace_state) { 1117 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1118 return -EAGAIN; 1119 } 1120 1121 switch (state) { 1122 case TRACE_ON: 1123 rc = net_dm_trace_on_set(extack); 1124 break; 1125 case TRACE_OFF: 1126 net_dm_trace_off_set(); 1127 break; 1128 default: 1129 rc = 1; 1130 break; 1131 } 1132 1133 if (!rc) 1134 trace_state = state; 1135 else 1136 rc = -EINPROGRESS; 1137 1138 return rc; 1139 } 1140 1141 static bool net_dm_is_monitoring(void) 1142 { 1143 return trace_state == TRACE_ON || monitor_hw; 1144 } 1145 1146 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1147 enum net_dm_alert_mode *p_alert_mode) 1148 { 1149 u8 val; 1150 1151 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1152 1153 switch (val) { 1154 case NET_DM_ALERT_MODE_SUMMARY: /* fall-through */ 1155 case NET_DM_ALERT_MODE_PACKET: 1156 *p_alert_mode = val; 1157 break; 1158 default: 1159 return -EINVAL; 1160 } 1161 1162 return 0; 1163 } 1164 1165 static int net_dm_alert_mode_set(struct genl_info *info) 1166 { 1167 struct netlink_ext_ack *extack = info->extack; 1168 enum net_dm_alert_mode alert_mode; 1169 int rc; 1170 1171 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1172 return 0; 1173 1174 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1175 if (rc) { 1176 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1177 return -EINVAL; 1178 } 1179 1180 net_dm_alert_mode = alert_mode; 1181 1182 return 0; 1183 } 1184 1185 static void net_dm_trunc_len_set(struct genl_info *info) 1186 { 1187 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1188 return; 1189 1190 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1191 } 1192 1193 static void net_dm_queue_len_set(struct genl_info *info) 1194 { 1195 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1196 return; 1197 1198 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1199 } 1200 1201 static int net_dm_cmd_config(struct sk_buff *skb, 1202 struct genl_info *info) 1203 { 1204 struct netlink_ext_ack *extack = info->extack; 1205 int rc; 1206 1207 if (net_dm_is_monitoring()) { 1208 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1209 return -EBUSY; 1210 } 1211 1212 rc = net_dm_alert_mode_set(info); 1213 if (rc) 1214 return rc; 1215 1216 net_dm_trunc_len_set(info); 1217 1218 net_dm_queue_len_set(info); 1219 1220 return 0; 1221 } 1222 1223 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1224 struct netlink_ext_ack *extack) 1225 { 1226 bool sw_set = false; 1227 int rc; 1228 1229 if (set_sw) { 1230 rc = set_all_monitor_traces(TRACE_ON, extack); 1231 if (rc) 1232 return rc; 1233 sw_set = true; 1234 } 1235 1236 if (set_hw) { 1237 rc = net_dm_hw_monitor_start(extack); 1238 if (rc) 1239 goto err_monitor_hw; 1240 } 1241 1242 return 0; 1243 1244 err_monitor_hw: 1245 if (sw_set) 1246 set_all_monitor_traces(TRACE_OFF, extack); 1247 return rc; 1248 } 1249 1250 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1251 struct netlink_ext_ack *extack) 1252 { 1253 if (set_hw) 1254 net_dm_hw_monitor_stop(extack); 1255 if (set_sw) 1256 set_all_monitor_traces(TRACE_OFF, extack); 1257 } 1258 1259 static int net_dm_cmd_trace(struct sk_buff *skb, 1260 struct genl_info *info) 1261 { 1262 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1263 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1264 struct netlink_ext_ack *extack = info->extack; 1265 1266 /* To maintain backward compatibility, we start / stop monitoring of 1267 * software drops if no flag is specified. 1268 */ 1269 if (!set_sw && !set_hw) 1270 set_sw = true; 1271 1272 switch (info->genlhdr->cmd) { 1273 case NET_DM_CMD_START: 1274 return net_dm_monitor_start(set_sw, set_hw, extack); 1275 case NET_DM_CMD_STOP: 1276 net_dm_monitor_stop(set_sw, set_hw, extack); 1277 return 0; 1278 } 1279 1280 return -EOPNOTSUPP; 1281 } 1282 1283 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1284 { 1285 void *hdr; 1286 1287 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1288 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1289 if (!hdr) 1290 return -EMSGSIZE; 1291 1292 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1293 goto nla_put_failure; 1294 1295 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1296 goto nla_put_failure; 1297 1298 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1299 goto nla_put_failure; 1300 1301 genlmsg_end(msg, hdr); 1302 1303 return 0; 1304 1305 nla_put_failure: 1306 genlmsg_cancel(msg, hdr); 1307 return -EMSGSIZE; 1308 } 1309 1310 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1311 { 1312 struct sk_buff *msg; 1313 int rc; 1314 1315 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1316 if (!msg) 1317 return -ENOMEM; 1318 1319 rc = net_dm_config_fill(msg, info); 1320 if (rc) 1321 goto free_msg; 1322 1323 return genlmsg_reply(msg, info); 1324 1325 free_msg: 1326 nlmsg_free(msg); 1327 return rc; 1328 } 1329 1330 static void net_dm_stats_read(struct net_dm_stats *stats) 1331 { 1332 int cpu; 1333 1334 memset(stats, 0, sizeof(*stats)); 1335 for_each_possible_cpu(cpu) { 1336 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1337 struct net_dm_stats *cpu_stats = &data->stats; 1338 unsigned int start; 1339 u64 dropped; 1340 1341 do { 1342 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1343 dropped = cpu_stats->dropped; 1344 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1345 1346 stats->dropped += dropped; 1347 } 1348 } 1349 1350 static int net_dm_stats_put(struct sk_buff *msg) 1351 { 1352 struct net_dm_stats stats; 1353 struct nlattr *attr; 1354 1355 net_dm_stats_read(&stats); 1356 1357 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1358 if (!attr) 1359 return -EMSGSIZE; 1360 1361 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1362 stats.dropped, NET_DM_ATTR_PAD)) 1363 goto nla_put_failure; 1364 1365 nla_nest_end(msg, attr); 1366 1367 return 0; 1368 1369 nla_put_failure: 1370 nla_nest_cancel(msg, attr); 1371 return -EMSGSIZE; 1372 } 1373 1374 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1375 { 1376 int cpu; 1377 1378 memset(stats, 0, sizeof(*stats)); 1379 for_each_possible_cpu(cpu) { 1380 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1381 struct net_dm_stats *cpu_stats = &hw_data->stats; 1382 unsigned int start; 1383 u64 dropped; 1384 1385 do { 1386 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1387 dropped = cpu_stats->dropped; 1388 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1389 1390 stats->dropped += dropped; 1391 } 1392 } 1393 1394 static int net_dm_hw_stats_put(struct sk_buff *msg) 1395 { 1396 struct net_dm_stats stats; 1397 struct nlattr *attr; 1398 1399 net_dm_hw_stats_read(&stats); 1400 1401 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1402 if (!attr) 1403 return -EMSGSIZE; 1404 1405 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1406 stats.dropped, NET_DM_ATTR_PAD)) 1407 goto nla_put_failure; 1408 1409 nla_nest_end(msg, attr); 1410 1411 return 0; 1412 1413 nla_put_failure: 1414 nla_nest_cancel(msg, attr); 1415 return -EMSGSIZE; 1416 } 1417 1418 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1419 { 1420 void *hdr; 1421 int rc; 1422 1423 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1424 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1425 if (!hdr) 1426 return -EMSGSIZE; 1427 1428 rc = net_dm_stats_put(msg); 1429 if (rc) 1430 goto nla_put_failure; 1431 1432 rc = net_dm_hw_stats_put(msg); 1433 if (rc) 1434 goto nla_put_failure; 1435 1436 genlmsg_end(msg, hdr); 1437 1438 return 0; 1439 1440 nla_put_failure: 1441 genlmsg_cancel(msg, hdr); 1442 return -EMSGSIZE; 1443 } 1444 1445 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1446 { 1447 struct sk_buff *msg; 1448 int rc; 1449 1450 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1451 if (!msg) 1452 return -ENOMEM; 1453 1454 rc = net_dm_stats_fill(msg, info); 1455 if (rc) 1456 goto free_msg; 1457 1458 return genlmsg_reply(msg, info); 1459 1460 free_msg: 1461 nlmsg_free(msg); 1462 return rc; 1463 } 1464 1465 static int dropmon_net_event(struct notifier_block *ev_block, 1466 unsigned long event, void *ptr) 1467 { 1468 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1469 struct dm_hw_stat_delta *new_stat = NULL; 1470 struct dm_hw_stat_delta *tmp; 1471 1472 switch (event) { 1473 case NETDEV_REGISTER: 1474 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); 1475 1476 if (!new_stat) 1477 goto out; 1478 1479 new_stat->dev = dev; 1480 new_stat->last_rx = jiffies; 1481 mutex_lock(&net_dm_mutex); 1482 list_add_rcu(&new_stat->list, &hw_stats_list); 1483 mutex_unlock(&net_dm_mutex); 1484 break; 1485 case NETDEV_UNREGISTER: 1486 mutex_lock(&net_dm_mutex); 1487 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { 1488 if (new_stat->dev == dev) { 1489 new_stat->dev = NULL; 1490 if (trace_state == TRACE_OFF) { 1491 list_del_rcu(&new_stat->list); 1492 kfree_rcu(new_stat, rcu); 1493 break; 1494 } 1495 } 1496 } 1497 mutex_unlock(&net_dm_mutex); 1498 break; 1499 } 1500 out: 1501 return NOTIFY_DONE; 1502 } 1503 1504 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1505 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1506 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1507 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1508 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1509 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1510 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1511 }; 1512 1513 static const struct genl_ops dropmon_ops[] = { 1514 { 1515 .cmd = NET_DM_CMD_CONFIG, 1516 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1517 .doit = net_dm_cmd_config, 1518 .flags = GENL_ADMIN_PERM, 1519 }, 1520 { 1521 .cmd = NET_DM_CMD_START, 1522 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1523 .doit = net_dm_cmd_trace, 1524 }, 1525 { 1526 .cmd = NET_DM_CMD_STOP, 1527 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1528 .doit = net_dm_cmd_trace, 1529 }, 1530 { 1531 .cmd = NET_DM_CMD_CONFIG_GET, 1532 .doit = net_dm_cmd_config_get, 1533 }, 1534 { 1535 .cmd = NET_DM_CMD_STATS_GET, 1536 .doit = net_dm_cmd_stats_get, 1537 }, 1538 }; 1539 1540 static int net_dm_nl_pre_doit(const struct genl_ops *ops, 1541 struct sk_buff *skb, struct genl_info *info) 1542 { 1543 mutex_lock(&net_dm_mutex); 1544 1545 return 0; 1546 } 1547 1548 static void net_dm_nl_post_doit(const struct genl_ops *ops, 1549 struct sk_buff *skb, struct genl_info *info) 1550 { 1551 mutex_unlock(&net_dm_mutex); 1552 } 1553 1554 static struct genl_family net_drop_monitor_family __ro_after_init = { 1555 .hdrsize = 0, 1556 .name = "NET_DM", 1557 .version = 2, 1558 .maxattr = NET_DM_ATTR_MAX, 1559 .policy = net_dm_nl_policy, 1560 .pre_doit = net_dm_nl_pre_doit, 1561 .post_doit = net_dm_nl_post_doit, 1562 .module = THIS_MODULE, 1563 .ops = dropmon_ops, 1564 .n_ops = ARRAY_SIZE(dropmon_ops), 1565 .mcgrps = dropmon_mcgrps, 1566 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1567 }; 1568 1569 static struct notifier_block dropmon_net_notifier = { 1570 .notifier_call = dropmon_net_event 1571 }; 1572 1573 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1574 { 1575 spin_lock_init(&data->lock); 1576 skb_queue_head_init(&data->drop_queue); 1577 u64_stats_init(&data->stats.syncp); 1578 } 1579 1580 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1581 { 1582 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1583 } 1584 1585 static void net_dm_cpu_data_init(int cpu) 1586 { 1587 struct per_cpu_dm_data *data; 1588 1589 data = &per_cpu(dm_cpu_data, cpu); 1590 __net_dm_cpu_data_init(data); 1591 } 1592 1593 static void net_dm_cpu_data_fini(int cpu) 1594 { 1595 struct per_cpu_dm_data *data; 1596 1597 data = &per_cpu(dm_cpu_data, cpu); 1598 /* At this point, we should have exclusive access 1599 * to this struct and can free the skb inside it. 1600 */ 1601 consume_skb(data->skb); 1602 __net_dm_cpu_data_fini(data); 1603 } 1604 1605 static void net_dm_hw_cpu_data_init(int cpu) 1606 { 1607 struct per_cpu_dm_data *hw_data; 1608 1609 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1610 __net_dm_cpu_data_init(hw_data); 1611 } 1612 1613 static void net_dm_hw_cpu_data_fini(int cpu) 1614 { 1615 struct per_cpu_dm_data *hw_data; 1616 1617 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1618 kfree(hw_data->hw_entries); 1619 __net_dm_cpu_data_fini(hw_data); 1620 } 1621 1622 static int __init init_net_drop_monitor(void) 1623 { 1624 int cpu, rc; 1625 1626 pr_info("Initializing network drop monitor service\n"); 1627 1628 if (sizeof(void *) > 8) { 1629 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1630 return -ENOSPC; 1631 } 1632 1633 rc = genl_register_family(&net_drop_monitor_family); 1634 if (rc) { 1635 pr_err("Could not create drop monitor netlink family\n"); 1636 return rc; 1637 } 1638 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1639 1640 rc = register_netdevice_notifier(&dropmon_net_notifier); 1641 if (rc < 0) { 1642 pr_crit("Failed to register netdevice notifier\n"); 1643 goto out_unreg; 1644 } 1645 1646 rc = 0; 1647 1648 for_each_possible_cpu(cpu) { 1649 net_dm_cpu_data_init(cpu); 1650 net_dm_hw_cpu_data_init(cpu); 1651 } 1652 1653 goto out; 1654 1655 out_unreg: 1656 genl_unregister_family(&net_drop_monitor_family); 1657 out: 1658 return rc; 1659 } 1660 1661 static void exit_net_drop_monitor(void) 1662 { 1663 int cpu; 1664 1665 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1666 1667 /* 1668 * Because of the module_get/put we do in the trace state change path 1669 * we are guarnateed not to have any current users when we get here 1670 */ 1671 1672 for_each_possible_cpu(cpu) { 1673 net_dm_hw_cpu_data_fini(cpu); 1674 net_dm_cpu_data_fini(cpu); 1675 } 1676 1677 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1678 } 1679 1680 module_init(init_net_drop_monitor); 1681 module_exit(exit_net_drop_monitor); 1682 1683 MODULE_LICENSE("GPL v2"); 1684 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1685 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1686