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 #include <net/flow_offload.h> 33 34 #include <trace/events/skb.h> 35 #include <trace/events/napi.h> 36 37 #include <asm/unaligned.h> 38 39 #define TRACE_ON 1 40 #define TRACE_OFF 0 41 42 /* 43 * Globals, our netlink socket pointer 44 * and the work handle that will send up 45 * netlink alerts 46 */ 47 static int trace_state = TRACE_OFF; 48 static bool monitor_hw; 49 50 /* net_dm_mutex 51 * 52 * An overall lock guarding every operation coming from userspace. 53 * It also guards the global 'hw_stats_list' list. 54 */ 55 static DEFINE_MUTEX(net_dm_mutex); 56 57 struct net_dm_stats { 58 u64 dropped; 59 struct u64_stats_sync syncp; 60 }; 61 62 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40 63 64 struct net_dm_hw_entry { 65 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN]; 66 u32 count; 67 }; 68 69 struct net_dm_hw_entries { 70 u32 num_entries; 71 struct net_dm_hw_entry entries[]; 72 }; 73 74 struct per_cpu_dm_data { 75 spinlock_t lock; /* Protects 'skb', 'hw_entries' and 76 * 'send_timer' 77 */ 78 union { 79 struct sk_buff *skb; 80 struct net_dm_hw_entries *hw_entries; 81 }; 82 struct sk_buff_head drop_queue; 83 struct work_struct dm_alert_work; 84 struct timer_list send_timer; 85 struct net_dm_stats stats; 86 }; 87 88 struct dm_hw_stat_delta { 89 struct net_device *dev; 90 unsigned long last_rx; 91 struct list_head list; 92 struct rcu_head rcu; 93 unsigned long last_drop_val; 94 }; 95 96 static struct genl_family net_drop_monitor_family; 97 98 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); 99 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data); 100 101 static int dm_hit_limit = 64; 102 static int dm_delay = 1; 103 static unsigned long dm_hw_check_delta = 2*HZ; 104 static LIST_HEAD(hw_stats_list); 105 106 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY; 107 static u32 net_dm_trunc_len; 108 static u32 net_dm_queue_len = 1000; 109 110 struct net_dm_alert_ops { 111 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, 112 void *location); 113 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi, 114 int work, int budget); 115 void (*work_item_func)(struct work_struct *work); 116 void (*hw_work_item_func)(struct work_struct *work); 117 void (*hw_probe)(struct sk_buff *skb, 118 const struct net_dm_hw_metadata *hw_metadata); 119 }; 120 121 struct net_dm_skb_cb { 122 union { 123 struct net_dm_hw_metadata *hw_metadata; 124 void *pc; 125 }; 126 }; 127 128 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) 129 130 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) 131 { 132 size_t al; 133 struct net_dm_alert_msg *msg; 134 struct nlattr *nla; 135 struct sk_buff *skb; 136 unsigned long flags; 137 void *msg_header; 138 139 al = sizeof(struct net_dm_alert_msg); 140 al += dm_hit_limit * sizeof(struct net_dm_drop_point); 141 al += sizeof(struct nlattr); 142 143 skb = genlmsg_new(al, GFP_KERNEL); 144 145 if (!skb) 146 goto err; 147 148 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family, 149 0, NET_DM_CMD_ALERT); 150 if (!msg_header) { 151 nlmsg_free(skb); 152 skb = NULL; 153 goto err; 154 } 155 nla = nla_reserve(skb, NLA_UNSPEC, 156 sizeof(struct net_dm_alert_msg)); 157 if (!nla) { 158 nlmsg_free(skb); 159 skb = NULL; 160 goto err; 161 } 162 msg = nla_data(nla); 163 memset(msg, 0, al); 164 goto out; 165 166 err: 167 mod_timer(&data->send_timer, jiffies + HZ / 10); 168 out: 169 spin_lock_irqsave(&data->lock, flags); 170 swap(data->skb, skb); 171 spin_unlock_irqrestore(&data->lock, flags); 172 173 if (skb) { 174 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; 175 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh); 176 177 genlmsg_end(skb, genlmsg_data(gnlh)); 178 } 179 180 return skb; 181 } 182 183 static const struct genl_multicast_group dropmon_mcgrps[] = { 184 { .name = "events", }, 185 }; 186 187 static void send_dm_alert(struct work_struct *work) 188 { 189 struct sk_buff *skb; 190 struct per_cpu_dm_data *data; 191 192 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 193 194 skb = reset_per_cpu_data(data); 195 196 if (skb) 197 genlmsg_multicast(&net_drop_monitor_family, skb, 0, 198 0, GFP_KERNEL); 199 } 200 201 /* 202 * This is the timer function to delay the sending of an alert 203 * in the event that more drops will arrive during the 204 * hysteresis period. 205 */ 206 static void sched_send_work(struct timer_list *t) 207 { 208 struct per_cpu_dm_data *data = from_timer(data, t, send_timer); 209 210 schedule_work(&data->dm_alert_work); 211 } 212 213 static void trace_drop_common(struct sk_buff *skb, void *location) 214 { 215 struct net_dm_alert_msg *msg; 216 struct net_dm_drop_point *point; 217 struct nlmsghdr *nlh; 218 struct nlattr *nla; 219 int i; 220 struct sk_buff *dskb; 221 struct per_cpu_dm_data *data; 222 unsigned long flags; 223 224 local_irq_save(flags); 225 data = this_cpu_ptr(&dm_cpu_data); 226 spin_lock(&data->lock); 227 dskb = data->skb; 228 229 if (!dskb) 230 goto out; 231 232 nlh = (struct nlmsghdr *)dskb->data; 233 nla = genlmsg_data(nlmsg_data(nlh)); 234 msg = nla_data(nla); 235 point = msg->points; 236 for (i = 0; i < msg->entries; i++) { 237 if (!memcmp(&location, &point->pc, sizeof(void *))) { 238 point->count++; 239 goto out; 240 } 241 point++; 242 } 243 if (msg->entries == dm_hit_limit) 244 goto out; 245 /* 246 * We need to create a new entry 247 */ 248 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point)); 249 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); 250 memcpy(point->pc, &location, sizeof(void *)); 251 point->count = 1; 252 msg->entries++; 253 254 if (!timer_pending(&data->send_timer)) { 255 data->send_timer.expires = jiffies + dm_delay * HZ; 256 add_timer(&data->send_timer); 257 } 258 259 out: 260 spin_unlock_irqrestore(&data->lock, flags); 261 } 262 263 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location) 264 { 265 trace_drop_common(skb, location); 266 } 267 268 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, 269 int work, int budget) 270 { 271 struct dm_hw_stat_delta *new_stat; 272 273 /* 274 * Don't check napi structures with no associated device 275 */ 276 if (!napi->dev) 277 return; 278 279 rcu_read_lock(); 280 list_for_each_entry_rcu(new_stat, &hw_stats_list, list) { 281 /* 282 * only add a note to our monitor buffer if: 283 * 1) this is the dev we received on 284 * 2) its after the last_rx delta 285 * 3) our rx_dropped count has gone up 286 */ 287 if ((new_stat->dev == napi->dev) && 288 (time_after(jiffies, new_stat->last_rx + dm_hw_check_delta)) && 289 (napi->dev->stats.rx_dropped != new_stat->last_drop_val)) { 290 trace_drop_common(NULL, NULL); 291 new_stat->last_drop_val = napi->dev->stats.rx_dropped; 292 new_stat->last_rx = jiffies; 293 break; 294 } 295 } 296 rcu_read_unlock(); 297 } 298 299 static struct net_dm_hw_entries * 300 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data) 301 { 302 struct net_dm_hw_entries *hw_entries; 303 unsigned long flags; 304 305 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit), 306 GFP_KERNEL); 307 if (!hw_entries) { 308 /* If the memory allocation failed, we try to perform another 309 * allocation in 1/10 second. Otherwise, the probe function 310 * will constantly bail out. 311 */ 312 mod_timer(&hw_data->send_timer, jiffies + HZ / 10); 313 } 314 315 spin_lock_irqsave(&hw_data->lock, flags); 316 swap(hw_data->hw_entries, hw_entries); 317 spin_unlock_irqrestore(&hw_data->lock, flags); 318 319 return hw_entries; 320 } 321 322 static int net_dm_hw_entry_put(struct sk_buff *msg, 323 const struct net_dm_hw_entry *hw_entry) 324 { 325 struct nlattr *attr; 326 327 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY); 328 if (!attr) 329 return -EMSGSIZE; 330 331 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name)) 332 goto nla_put_failure; 333 334 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count)) 335 goto nla_put_failure; 336 337 nla_nest_end(msg, attr); 338 339 return 0; 340 341 nla_put_failure: 342 nla_nest_cancel(msg, attr); 343 return -EMSGSIZE; 344 } 345 346 static int net_dm_hw_entries_put(struct sk_buff *msg, 347 const struct net_dm_hw_entries *hw_entries) 348 { 349 struct nlattr *attr; 350 int i; 351 352 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES); 353 if (!attr) 354 return -EMSGSIZE; 355 356 for (i = 0; i < hw_entries->num_entries; i++) { 357 int rc; 358 359 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]); 360 if (rc) 361 goto nla_put_failure; 362 } 363 364 nla_nest_end(msg, attr); 365 366 return 0; 367 368 nla_put_failure: 369 nla_nest_cancel(msg, attr); 370 return -EMSGSIZE; 371 } 372 373 static int 374 net_dm_hw_summary_report_fill(struct sk_buff *msg, 375 const struct net_dm_hw_entries *hw_entries) 376 { 377 struct net_dm_alert_msg anc_hdr = { 0 }; 378 void *hdr; 379 int rc; 380 381 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 382 NET_DM_CMD_ALERT); 383 if (!hdr) 384 return -EMSGSIZE; 385 386 /* We need to put the ancillary header in order not to break user 387 * space. 388 */ 389 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr)) 390 goto nla_put_failure; 391 392 rc = net_dm_hw_entries_put(msg, hw_entries); 393 if (rc) 394 goto nla_put_failure; 395 396 genlmsg_end(msg, hdr); 397 398 return 0; 399 400 nla_put_failure: 401 genlmsg_cancel(msg, hdr); 402 return -EMSGSIZE; 403 } 404 405 static void net_dm_hw_summary_work(struct work_struct *work) 406 { 407 struct net_dm_hw_entries *hw_entries; 408 struct per_cpu_dm_data *hw_data; 409 struct sk_buff *msg; 410 int rc; 411 412 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 413 414 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 415 if (!hw_entries) 416 return; 417 418 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 419 if (!msg) 420 goto out; 421 422 rc = net_dm_hw_summary_report_fill(msg, hw_entries); 423 if (rc) { 424 nlmsg_free(msg); 425 goto out; 426 } 427 428 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 429 430 out: 431 kfree(hw_entries); 432 } 433 434 static void 435 net_dm_hw_summary_probe(struct sk_buff *skb, 436 const struct net_dm_hw_metadata *hw_metadata) 437 { 438 struct net_dm_hw_entries *hw_entries; 439 struct net_dm_hw_entry *hw_entry; 440 struct per_cpu_dm_data *hw_data; 441 unsigned long flags; 442 int i; 443 444 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 445 spin_lock_irqsave(&hw_data->lock, flags); 446 hw_entries = hw_data->hw_entries; 447 448 if (!hw_entries) 449 goto out; 450 451 for (i = 0; i < hw_entries->num_entries; i++) { 452 hw_entry = &hw_entries->entries[i]; 453 if (!strncmp(hw_entry->trap_name, hw_metadata->trap_name, 454 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) { 455 hw_entry->count++; 456 goto out; 457 } 458 } 459 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit)) 460 goto out; 461 462 hw_entry = &hw_entries->entries[hw_entries->num_entries]; 463 strlcpy(hw_entry->trap_name, hw_metadata->trap_name, 464 NET_DM_MAX_HW_TRAP_NAME_LEN - 1); 465 hw_entry->count = 1; 466 hw_entries->num_entries++; 467 468 if (!timer_pending(&hw_data->send_timer)) { 469 hw_data->send_timer.expires = jiffies + dm_delay * HZ; 470 add_timer(&hw_data->send_timer); 471 } 472 473 out: 474 spin_unlock_irqrestore(&hw_data->lock, flags); 475 } 476 477 static const struct net_dm_alert_ops net_dm_alert_summary_ops = { 478 .kfree_skb_probe = trace_kfree_skb_hit, 479 .napi_poll_probe = trace_napi_poll_hit, 480 .work_item_func = send_dm_alert, 481 .hw_work_item_func = net_dm_hw_summary_work, 482 .hw_probe = net_dm_hw_summary_probe, 483 }; 484 485 static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 486 struct sk_buff *skb, 487 void *location) 488 { 489 ktime_t tstamp = ktime_get_real(); 490 struct per_cpu_dm_data *data; 491 struct sk_buff *nskb; 492 unsigned long flags; 493 494 if (!skb_mac_header_was_set(skb)) 495 return; 496 497 nskb = skb_clone(skb, GFP_ATOMIC); 498 if (!nskb) 499 return; 500 501 NET_DM_SKB_CB(nskb)->pc = location; 502 /* Override the timestamp because we care about the time when the 503 * packet was dropped. 504 */ 505 nskb->tstamp = tstamp; 506 507 data = this_cpu_ptr(&dm_cpu_data); 508 509 spin_lock_irqsave(&data->drop_queue.lock, flags); 510 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 511 __skb_queue_tail(&data->drop_queue, nskb); 512 else 513 goto unlock_free; 514 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 515 516 schedule_work(&data->dm_alert_work); 517 518 return; 519 520 unlock_free: 521 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 522 u64_stats_update_begin(&data->stats.syncp); 523 data->stats.dropped++; 524 u64_stats_update_end(&data->stats.syncp); 525 consume_skb(nskb); 526 } 527 528 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 529 struct napi_struct *napi, 530 int work, int budget) 531 { 532 } 533 534 static size_t net_dm_in_port_size(void) 535 { 536 /* NET_DM_ATTR_IN_PORT nest */ 537 return nla_total_size(0) + 538 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 539 nla_total_size(sizeof(u32)) + 540 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 541 nla_total_size(IFNAMSIZ + 1); 542 } 543 544 #define NET_DM_MAX_SYMBOL_LEN 40 545 546 static size_t net_dm_packet_report_size(size_t payload_len) 547 { 548 size_t size; 549 550 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 551 552 return NLMSG_ALIGN(size) + 553 /* NET_DM_ATTR_ORIGIN */ 554 nla_total_size(sizeof(u16)) + 555 /* NET_DM_ATTR_PC */ 556 nla_total_size(sizeof(u64)) + 557 /* NET_DM_ATTR_SYMBOL */ 558 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 559 /* NET_DM_ATTR_IN_PORT */ 560 net_dm_in_port_size() + 561 /* NET_DM_ATTR_TIMESTAMP */ 562 nla_total_size(sizeof(u64)) + 563 /* NET_DM_ATTR_ORIG_LEN */ 564 nla_total_size(sizeof(u32)) + 565 /* NET_DM_ATTR_PROTO */ 566 nla_total_size(sizeof(u16)) + 567 /* NET_DM_ATTR_PAYLOAD */ 568 nla_total_size(payload_len); 569 } 570 571 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 572 const char *name) 573 { 574 struct nlattr *attr; 575 576 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 577 if (!attr) 578 return -EMSGSIZE; 579 580 if (ifindex && 581 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 582 goto nla_put_failure; 583 584 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 585 goto nla_put_failure; 586 587 nla_nest_end(msg, attr); 588 589 return 0; 590 591 nla_put_failure: 592 nla_nest_cancel(msg, attr); 593 return -EMSGSIZE; 594 } 595 596 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 597 size_t payload_len) 598 { 599 u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc; 600 char buf[NET_DM_MAX_SYMBOL_LEN]; 601 struct nlattr *attr; 602 void *hdr; 603 int rc; 604 605 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 606 NET_DM_CMD_PACKET_ALERT); 607 if (!hdr) 608 return -EMSGSIZE; 609 610 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 611 goto nla_put_failure; 612 613 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD)) 614 goto nla_put_failure; 615 616 snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc); 617 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 618 goto nla_put_failure; 619 620 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 621 if (rc) 622 goto nla_put_failure; 623 624 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 625 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 626 goto nla_put_failure; 627 628 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 629 goto nla_put_failure; 630 631 if (!payload_len) 632 goto out; 633 634 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 635 goto nla_put_failure; 636 637 attr = skb_put(msg, nla_total_size(payload_len)); 638 attr->nla_type = NET_DM_ATTR_PAYLOAD; 639 attr->nla_len = nla_attr_size(payload_len); 640 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 641 goto nla_put_failure; 642 643 out: 644 genlmsg_end(msg, hdr); 645 646 return 0; 647 648 nla_put_failure: 649 genlmsg_cancel(msg, hdr); 650 return -EMSGSIZE; 651 } 652 653 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 654 655 static void net_dm_packet_report(struct sk_buff *skb) 656 { 657 struct sk_buff *msg; 658 size_t payload_len; 659 int rc; 660 661 /* Make sure we start copying the packet from the MAC header */ 662 if (skb->data > skb_mac_header(skb)) 663 skb_push(skb, skb->data - skb_mac_header(skb)); 664 else 665 skb_pull(skb, skb_mac_header(skb) - skb->data); 666 667 /* Ensure packet fits inside a single netlink attribute */ 668 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 669 if (net_dm_trunc_len) 670 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 671 672 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 673 if (!msg) 674 goto out; 675 676 rc = net_dm_packet_report_fill(msg, skb, payload_len); 677 if (rc) { 678 nlmsg_free(msg); 679 goto out; 680 } 681 682 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 683 684 out: 685 consume_skb(skb); 686 } 687 688 static void net_dm_packet_work(struct work_struct *work) 689 { 690 struct per_cpu_dm_data *data; 691 struct sk_buff_head list; 692 struct sk_buff *skb; 693 unsigned long flags; 694 695 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 696 697 __skb_queue_head_init(&list); 698 699 spin_lock_irqsave(&data->drop_queue.lock, flags); 700 skb_queue_splice_tail_init(&data->drop_queue, &list); 701 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 702 703 while ((skb = __skb_dequeue(&list))) 704 net_dm_packet_report(skb); 705 } 706 707 static size_t 708 net_dm_flow_action_cookie_size(const struct net_dm_hw_metadata *hw_metadata) 709 { 710 return hw_metadata->fa_cookie ? 711 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 712 } 713 714 static size_t 715 net_dm_hw_packet_report_size(size_t payload_len, 716 const struct net_dm_hw_metadata *hw_metadata) 717 { 718 size_t size; 719 720 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 721 722 return NLMSG_ALIGN(size) + 723 /* NET_DM_ATTR_ORIGIN */ 724 nla_total_size(sizeof(u16)) + 725 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 726 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 727 /* NET_DM_ATTR_HW_TRAP_NAME */ 728 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 729 /* NET_DM_ATTR_IN_PORT */ 730 net_dm_in_port_size() + 731 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 732 net_dm_flow_action_cookie_size(hw_metadata) + 733 /* NET_DM_ATTR_TIMESTAMP */ 734 nla_total_size(sizeof(u64)) + 735 /* NET_DM_ATTR_ORIG_LEN */ 736 nla_total_size(sizeof(u32)) + 737 /* NET_DM_ATTR_PROTO */ 738 nla_total_size(sizeof(u16)) + 739 /* NET_DM_ATTR_PAYLOAD */ 740 nla_total_size(payload_len); 741 } 742 743 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 744 struct sk_buff *skb, size_t payload_len) 745 { 746 struct net_dm_hw_metadata *hw_metadata; 747 struct nlattr *attr; 748 void *hdr; 749 750 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 751 752 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 753 NET_DM_CMD_PACKET_ALERT); 754 if (!hdr) 755 return -EMSGSIZE; 756 757 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 758 goto nla_put_failure; 759 760 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 761 hw_metadata->trap_group_name)) 762 goto nla_put_failure; 763 764 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 765 hw_metadata->trap_name)) 766 goto nla_put_failure; 767 768 if (hw_metadata->input_dev) { 769 struct net_device *dev = hw_metadata->input_dev; 770 int rc; 771 772 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 773 dev->name); 774 if (rc) 775 goto nla_put_failure; 776 } 777 778 if (hw_metadata->fa_cookie && 779 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 780 hw_metadata->fa_cookie->cookie_len, 781 hw_metadata->fa_cookie->cookie)) 782 goto nla_put_failure; 783 784 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 785 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 786 goto nla_put_failure; 787 788 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 789 goto nla_put_failure; 790 791 if (!payload_len) 792 goto out; 793 794 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 795 goto nla_put_failure; 796 797 attr = skb_put(msg, nla_total_size(payload_len)); 798 attr->nla_type = NET_DM_ATTR_PAYLOAD; 799 attr->nla_len = nla_attr_size(payload_len); 800 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 801 goto nla_put_failure; 802 803 out: 804 genlmsg_end(msg, hdr); 805 806 return 0; 807 808 nla_put_failure: 809 genlmsg_cancel(msg, hdr); 810 return -EMSGSIZE; 811 } 812 813 static struct net_dm_hw_metadata * 814 net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata) 815 { 816 const struct flow_action_cookie *fa_cookie; 817 struct net_dm_hw_metadata *n_hw_metadata; 818 const char *trap_group_name; 819 const char *trap_name; 820 821 n_hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); 822 if (!n_hw_metadata) 823 return NULL; 824 825 trap_group_name = kstrdup(hw_metadata->trap_group_name, GFP_ATOMIC); 826 if (!trap_group_name) 827 goto free_hw_metadata; 828 n_hw_metadata->trap_group_name = trap_group_name; 829 830 trap_name = kstrdup(hw_metadata->trap_name, GFP_ATOMIC); 831 if (!trap_name) 832 goto free_trap_group; 833 n_hw_metadata->trap_name = trap_name; 834 835 if (hw_metadata->fa_cookie) { 836 size_t cookie_size = sizeof(*fa_cookie) + 837 hw_metadata->fa_cookie->cookie_len; 838 839 fa_cookie = kmemdup(hw_metadata->fa_cookie, cookie_size, 840 GFP_ATOMIC); 841 if (!fa_cookie) 842 goto free_trap_name; 843 n_hw_metadata->fa_cookie = fa_cookie; 844 } 845 846 n_hw_metadata->input_dev = hw_metadata->input_dev; 847 if (n_hw_metadata->input_dev) 848 dev_hold(n_hw_metadata->input_dev); 849 850 return n_hw_metadata; 851 852 free_trap_name: 853 kfree(trap_name); 854 free_trap_group: 855 kfree(trap_group_name); 856 free_hw_metadata: 857 kfree(n_hw_metadata); 858 return NULL; 859 } 860 861 static void 862 net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata) 863 { 864 if (hw_metadata->input_dev) 865 dev_put(hw_metadata->input_dev); 866 kfree(hw_metadata->fa_cookie); 867 kfree(hw_metadata->trap_name); 868 kfree(hw_metadata->trap_group_name); 869 kfree(hw_metadata); 870 } 871 872 static void net_dm_hw_packet_report(struct sk_buff *skb) 873 { 874 struct net_dm_hw_metadata *hw_metadata; 875 struct sk_buff *msg; 876 size_t payload_len; 877 int rc; 878 879 if (skb->data > skb_mac_header(skb)) 880 skb_push(skb, skb->data - skb_mac_header(skb)); 881 else 882 skb_pull(skb, skb_mac_header(skb) - skb->data); 883 884 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 885 if (net_dm_trunc_len) 886 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 887 888 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 889 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 890 GFP_KERNEL); 891 if (!msg) 892 goto out; 893 894 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 895 if (rc) { 896 nlmsg_free(msg); 897 goto out; 898 } 899 900 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 901 902 out: 903 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 904 consume_skb(skb); 905 } 906 907 static void net_dm_hw_packet_work(struct work_struct *work) 908 { 909 struct per_cpu_dm_data *hw_data; 910 struct sk_buff_head list; 911 struct sk_buff *skb; 912 unsigned long flags; 913 914 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 915 916 __skb_queue_head_init(&list); 917 918 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 919 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 920 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 921 922 while ((skb = __skb_dequeue(&list))) 923 net_dm_hw_packet_report(skb); 924 } 925 926 static void 927 net_dm_hw_packet_probe(struct sk_buff *skb, 928 const struct net_dm_hw_metadata *hw_metadata) 929 { 930 struct net_dm_hw_metadata *n_hw_metadata; 931 ktime_t tstamp = ktime_get_real(); 932 struct per_cpu_dm_data *hw_data; 933 struct sk_buff *nskb; 934 unsigned long flags; 935 936 if (!skb_mac_header_was_set(skb)) 937 return; 938 939 nskb = skb_clone(skb, GFP_ATOMIC); 940 if (!nskb) 941 return; 942 943 n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata); 944 if (!n_hw_metadata) 945 goto free; 946 947 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 948 nskb->tstamp = tstamp; 949 950 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 951 952 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 953 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 954 __skb_queue_tail(&hw_data->drop_queue, nskb); 955 else 956 goto unlock_free; 957 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 958 959 schedule_work(&hw_data->dm_alert_work); 960 961 return; 962 963 unlock_free: 964 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 965 u64_stats_update_begin(&hw_data->stats.syncp); 966 hw_data->stats.dropped++; 967 u64_stats_update_end(&hw_data->stats.syncp); 968 net_dm_hw_metadata_free(n_hw_metadata); 969 free: 970 consume_skb(nskb); 971 } 972 973 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 974 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 975 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 976 .work_item_func = net_dm_packet_work, 977 .hw_work_item_func = net_dm_hw_packet_work, 978 .hw_probe = net_dm_hw_packet_probe, 979 }; 980 981 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 982 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 983 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 984 }; 985 986 void net_dm_hw_report(struct sk_buff *skb, 987 const struct net_dm_hw_metadata *hw_metadata) 988 { 989 rcu_read_lock(); 990 991 if (!monitor_hw) 992 goto out; 993 994 net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata); 995 996 out: 997 rcu_read_unlock(); 998 } 999 EXPORT_SYMBOL_GPL(net_dm_hw_report); 1000 1001 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1002 { 1003 const struct net_dm_alert_ops *ops; 1004 int cpu; 1005 1006 if (monitor_hw) { 1007 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1008 return -EAGAIN; 1009 } 1010 1011 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1012 1013 if (!try_module_get(THIS_MODULE)) { 1014 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1015 return -ENODEV; 1016 } 1017 1018 for_each_possible_cpu(cpu) { 1019 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1020 struct net_dm_hw_entries *hw_entries; 1021 1022 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1023 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1024 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1025 kfree(hw_entries); 1026 } 1027 1028 monitor_hw = true; 1029 1030 return 0; 1031 } 1032 1033 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1034 { 1035 int cpu; 1036 1037 if (!monitor_hw) { 1038 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1039 return; 1040 } 1041 1042 monitor_hw = false; 1043 1044 /* After this call returns we are guaranteed that no CPU is processing 1045 * any hardware drops. 1046 */ 1047 synchronize_rcu(); 1048 1049 for_each_possible_cpu(cpu) { 1050 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1051 struct sk_buff *skb; 1052 1053 del_timer_sync(&hw_data->send_timer); 1054 cancel_work_sync(&hw_data->dm_alert_work); 1055 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1056 struct net_dm_hw_metadata *hw_metadata; 1057 1058 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1059 net_dm_hw_metadata_free(hw_metadata); 1060 consume_skb(skb); 1061 } 1062 } 1063 1064 module_put(THIS_MODULE); 1065 } 1066 1067 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1068 { 1069 const struct net_dm_alert_ops *ops; 1070 int cpu, rc; 1071 1072 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1073 1074 if (!try_module_get(THIS_MODULE)) { 1075 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1076 return -ENODEV; 1077 } 1078 1079 for_each_possible_cpu(cpu) { 1080 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1081 struct sk_buff *skb; 1082 1083 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1084 timer_setup(&data->send_timer, sched_send_work, 0); 1085 /* Allocate a new per-CPU skb for the summary alert message and 1086 * free the old one which might contain stale data from 1087 * previous tracing. 1088 */ 1089 skb = reset_per_cpu_data(data); 1090 consume_skb(skb); 1091 } 1092 1093 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1094 if (rc) { 1095 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1096 goto err_module_put; 1097 } 1098 1099 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1100 if (rc) { 1101 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1102 goto err_unregister_trace; 1103 } 1104 1105 return 0; 1106 1107 err_unregister_trace: 1108 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1109 err_module_put: 1110 module_put(THIS_MODULE); 1111 return rc; 1112 } 1113 1114 static void net_dm_trace_off_set(void) 1115 { 1116 struct dm_hw_stat_delta *new_stat, *temp; 1117 const struct net_dm_alert_ops *ops; 1118 int cpu; 1119 1120 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1121 1122 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1123 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1124 1125 tracepoint_synchronize_unregister(); 1126 1127 /* Make sure we do not send notifications to user space after request 1128 * to stop tracing returns. 1129 */ 1130 for_each_possible_cpu(cpu) { 1131 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1132 struct sk_buff *skb; 1133 1134 del_timer_sync(&data->send_timer); 1135 cancel_work_sync(&data->dm_alert_work); 1136 while ((skb = __skb_dequeue(&data->drop_queue))) 1137 consume_skb(skb); 1138 } 1139 1140 list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) { 1141 if (new_stat->dev == NULL) { 1142 list_del_rcu(&new_stat->list); 1143 kfree_rcu(new_stat, rcu); 1144 } 1145 } 1146 1147 module_put(THIS_MODULE); 1148 } 1149 1150 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1151 { 1152 int rc = 0; 1153 1154 if (state == trace_state) { 1155 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1156 return -EAGAIN; 1157 } 1158 1159 switch (state) { 1160 case TRACE_ON: 1161 rc = net_dm_trace_on_set(extack); 1162 break; 1163 case TRACE_OFF: 1164 net_dm_trace_off_set(); 1165 break; 1166 default: 1167 rc = 1; 1168 break; 1169 } 1170 1171 if (!rc) 1172 trace_state = state; 1173 else 1174 rc = -EINPROGRESS; 1175 1176 return rc; 1177 } 1178 1179 static bool net_dm_is_monitoring(void) 1180 { 1181 return trace_state == TRACE_ON || monitor_hw; 1182 } 1183 1184 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1185 enum net_dm_alert_mode *p_alert_mode) 1186 { 1187 u8 val; 1188 1189 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1190 1191 switch (val) { 1192 case NET_DM_ALERT_MODE_SUMMARY: 1193 case NET_DM_ALERT_MODE_PACKET: 1194 *p_alert_mode = val; 1195 break; 1196 default: 1197 return -EINVAL; 1198 } 1199 1200 return 0; 1201 } 1202 1203 static int net_dm_alert_mode_set(struct genl_info *info) 1204 { 1205 struct netlink_ext_ack *extack = info->extack; 1206 enum net_dm_alert_mode alert_mode; 1207 int rc; 1208 1209 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1210 return 0; 1211 1212 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1213 if (rc) { 1214 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1215 return -EINVAL; 1216 } 1217 1218 net_dm_alert_mode = alert_mode; 1219 1220 return 0; 1221 } 1222 1223 static void net_dm_trunc_len_set(struct genl_info *info) 1224 { 1225 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1226 return; 1227 1228 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1229 } 1230 1231 static void net_dm_queue_len_set(struct genl_info *info) 1232 { 1233 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1234 return; 1235 1236 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1237 } 1238 1239 static int net_dm_cmd_config(struct sk_buff *skb, 1240 struct genl_info *info) 1241 { 1242 struct netlink_ext_ack *extack = info->extack; 1243 int rc; 1244 1245 if (net_dm_is_monitoring()) { 1246 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1247 return -EBUSY; 1248 } 1249 1250 rc = net_dm_alert_mode_set(info); 1251 if (rc) 1252 return rc; 1253 1254 net_dm_trunc_len_set(info); 1255 1256 net_dm_queue_len_set(info); 1257 1258 return 0; 1259 } 1260 1261 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1262 struct netlink_ext_ack *extack) 1263 { 1264 bool sw_set = false; 1265 int rc; 1266 1267 if (set_sw) { 1268 rc = set_all_monitor_traces(TRACE_ON, extack); 1269 if (rc) 1270 return rc; 1271 sw_set = true; 1272 } 1273 1274 if (set_hw) { 1275 rc = net_dm_hw_monitor_start(extack); 1276 if (rc) 1277 goto err_monitor_hw; 1278 } 1279 1280 return 0; 1281 1282 err_monitor_hw: 1283 if (sw_set) 1284 set_all_monitor_traces(TRACE_OFF, extack); 1285 return rc; 1286 } 1287 1288 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1289 struct netlink_ext_ack *extack) 1290 { 1291 if (set_hw) 1292 net_dm_hw_monitor_stop(extack); 1293 if (set_sw) 1294 set_all_monitor_traces(TRACE_OFF, extack); 1295 } 1296 1297 static int net_dm_cmd_trace(struct sk_buff *skb, 1298 struct genl_info *info) 1299 { 1300 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1301 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1302 struct netlink_ext_ack *extack = info->extack; 1303 1304 /* To maintain backward compatibility, we start / stop monitoring of 1305 * software drops if no flag is specified. 1306 */ 1307 if (!set_sw && !set_hw) 1308 set_sw = true; 1309 1310 switch (info->genlhdr->cmd) { 1311 case NET_DM_CMD_START: 1312 return net_dm_monitor_start(set_sw, set_hw, extack); 1313 case NET_DM_CMD_STOP: 1314 net_dm_monitor_stop(set_sw, set_hw, extack); 1315 return 0; 1316 } 1317 1318 return -EOPNOTSUPP; 1319 } 1320 1321 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1322 { 1323 void *hdr; 1324 1325 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1326 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1327 if (!hdr) 1328 return -EMSGSIZE; 1329 1330 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1331 goto nla_put_failure; 1332 1333 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1334 goto nla_put_failure; 1335 1336 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1337 goto nla_put_failure; 1338 1339 genlmsg_end(msg, hdr); 1340 1341 return 0; 1342 1343 nla_put_failure: 1344 genlmsg_cancel(msg, hdr); 1345 return -EMSGSIZE; 1346 } 1347 1348 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1349 { 1350 struct sk_buff *msg; 1351 int rc; 1352 1353 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1354 if (!msg) 1355 return -ENOMEM; 1356 1357 rc = net_dm_config_fill(msg, info); 1358 if (rc) 1359 goto free_msg; 1360 1361 return genlmsg_reply(msg, info); 1362 1363 free_msg: 1364 nlmsg_free(msg); 1365 return rc; 1366 } 1367 1368 static void net_dm_stats_read(struct net_dm_stats *stats) 1369 { 1370 int cpu; 1371 1372 memset(stats, 0, sizeof(*stats)); 1373 for_each_possible_cpu(cpu) { 1374 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1375 struct net_dm_stats *cpu_stats = &data->stats; 1376 unsigned int start; 1377 u64 dropped; 1378 1379 do { 1380 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1381 dropped = cpu_stats->dropped; 1382 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1383 1384 stats->dropped += dropped; 1385 } 1386 } 1387 1388 static int net_dm_stats_put(struct sk_buff *msg) 1389 { 1390 struct net_dm_stats stats; 1391 struct nlattr *attr; 1392 1393 net_dm_stats_read(&stats); 1394 1395 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1396 if (!attr) 1397 return -EMSGSIZE; 1398 1399 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1400 stats.dropped, NET_DM_ATTR_PAD)) 1401 goto nla_put_failure; 1402 1403 nla_nest_end(msg, attr); 1404 1405 return 0; 1406 1407 nla_put_failure: 1408 nla_nest_cancel(msg, attr); 1409 return -EMSGSIZE; 1410 } 1411 1412 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1413 { 1414 int cpu; 1415 1416 memset(stats, 0, sizeof(*stats)); 1417 for_each_possible_cpu(cpu) { 1418 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1419 struct net_dm_stats *cpu_stats = &hw_data->stats; 1420 unsigned int start; 1421 u64 dropped; 1422 1423 do { 1424 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1425 dropped = cpu_stats->dropped; 1426 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1427 1428 stats->dropped += dropped; 1429 } 1430 } 1431 1432 static int net_dm_hw_stats_put(struct sk_buff *msg) 1433 { 1434 struct net_dm_stats stats; 1435 struct nlattr *attr; 1436 1437 net_dm_hw_stats_read(&stats); 1438 1439 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1440 if (!attr) 1441 return -EMSGSIZE; 1442 1443 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1444 stats.dropped, NET_DM_ATTR_PAD)) 1445 goto nla_put_failure; 1446 1447 nla_nest_end(msg, attr); 1448 1449 return 0; 1450 1451 nla_put_failure: 1452 nla_nest_cancel(msg, attr); 1453 return -EMSGSIZE; 1454 } 1455 1456 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1457 { 1458 void *hdr; 1459 int rc; 1460 1461 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1462 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1463 if (!hdr) 1464 return -EMSGSIZE; 1465 1466 rc = net_dm_stats_put(msg); 1467 if (rc) 1468 goto nla_put_failure; 1469 1470 rc = net_dm_hw_stats_put(msg); 1471 if (rc) 1472 goto nla_put_failure; 1473 1474 genlmsg_end(msg, hdr); 1475 1476 return 0; 1477 1478 nla_put_failure: 1479 genlmsg_cancel(msg, hdr); 1480 return -EMSGSIZE; 1481 } 1482 1483 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1484 { 1485 struct sk_buff *msg; 1486 int rc; 1487 1488 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1489 if (!msg) 1490 return -ENOMEM; 1491 1492 rc = net_dm_stats_fill(msg, info); 1493 if (rc) 1494 goto free_msg; 1495 1496 return genlmsg_reply(msg, info); 1497 1498 free_msg: 1499 nlmsg_free(msg); 1500 return rc; 1501 } 1502 1503 static int dropmon_net_event(struct notifier_block *ev_block, 1504 unsigned long event, void *ptr) 1505 { 1506 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1507 struct dm_hw_stat_delta *new_stat = NULL; 1508 struct dm_hw_stat_delta *tmp; 1509 1510 switch (event) { 1511 case NETDEV_REGISTER: 1512 new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL); 1513 1514 if (!new_stat) 1515 goto out; 1516 1517 new_stat->dev = dev; 1518 new_stat->last_rx = jiffies; 1519 mutex_lock(&net_dm_mutex); 1520 list_add_rcu(&new_stat->list, &hw_stats_list); 1521 mutex_unlock(&net_dm_mutex); 1522 break; 1523 case NETDEV_UNREGISTER: 1524 mutex_lock(&net_dm_mutex); 1525 list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) { 1526 if (new_stat->dev == dev) { 1527 new_stat->dev = NULL; 1528 if (trace_state == TRACE_OFF) { 1529 list_del_rcu(&new_stat->list); 1530 kfree_rcu(new_stat, rcu); 1531 break; 1532 } 1533 } 1534 } 1535 mutex_unlock(&net_dm_mutex); 1536 break; 1537 } 1538 out: 1539 return NOTIFY_DONE; 1540 } 1541 1542 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1543 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1544 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1545 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1546 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1547 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1548 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1549 }; 1550 1551 static const struct genl_ops dropmon_ops[] = { 1552 { 1553 .cmd = NET_DM_CMD_CONFIG, 1554 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1555 .doit = net_dm_cmd_config, 1556 .flags = GENL_ADMIN_PERM, 1557 }, 1558 { 1559 .cmd = NET_DM_CMD_START, 1560 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1561 .doit = net_dm_cmd_trace, 1562 }, 1563 { 1564 .cmd = NET_DM_CMD_STOP, 1565 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1566 .doit = net_dm_cmd_trace, 1567 }, 1568 { 1569 .cmd = NET_DM_CMD_CONFIG_GET, 1570 .doit = net_dm_cmd_config_get, 1571 }, 1572 { 1573 .cmd = NET_DM_CMD_STATS_GET, 1574 .doit = net_dm_cmd_stats_get, 1575 }, 1576 }; 1577 1578 static int net_dm_nl_pre_doit(const struct genl_ops *ops, 1579 struct sk_buff *skb, struct genl_info *info) 1580 { 1581 mutex_lock(&net_dm_mutex); 1582 1583 return 0; 1584 } 1585 1586 static void net_dm_nl_post_doit(const struct genl_ops *ops, 1587 struct sk_buff *skb, struct genl_info *info) 1588 { 1589 mutex_unlock(&net_dm_mutex); 1590 } 1591 1592 static struct genl_family net_drop_monitor_family __ro_after_init = { 1593 .hdrsize = 0, 1594 .name = "NET_DM", 1595 .version = 2, 1596 .maxattr = NET_DM_ATTR_MAX, 1597 .policy = net_dm_nl_policy, 1598 .pre_doit = net_dm_nl_pre_doit, 1599 .post_doit = net_dm_nl_post_doit, 1600 .module = THIS_MODULE, 1601 .ops = dropmon_ops, 1602 .n_ops = ARRAY_SIZE(dropmon_ops), 1603 .mcgrps = dropmon_mcgrps, 1604 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1605 }; 1606 1607 static struct notifier_block dropmon_net_notifier = { 1608 .notifier_call = dropmon_net_event 1609 }; 1610 1611 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1612 { 1613 spin_lock_init(&data->lock); 1614 skb_queue_head_init(&data->drop_queue); 1615 u64_stats_init(&data->stats.syncp); 1616 } 1617 1618 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1619 { 1620 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1621 } 1622 1623 static void net_dm_cpu_data_init(int cpu) 1624 { 1625 struct per_cpu_dm_data *data; 1626 1627 data = &per_cpu(dm_cpu_data, cpu); 1628 __net_dm_cpu_data_init(data); 1629 } 1630 1631 static void net_dm_cpu_data_fini(int cpu) 1632 { 1633 struct per_cpu_dm_data *data; 1634 1635 data = &per_cpu(dm_cpu_data, cpu); 1636 /* At this point, we should have exclusive access 1637 * to this struct and can free the skb inside it. 1638 */ 1639 consume_skb(data->skb); 1640 __net_dm_cpu_data_fini(data); 1641 } 1642 1643 static void net_dm_hw_cpu_data_init(int cpu) 1644 { 1645 struct per_cpu_dm_data *hw_data; 1646 1647 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1648 __net_dm_cpu_data_init(hw_data); 1649 } 1650 1651 static void net_dm_hw_cpu_data_fini(int cpu) 1652 { 1653 struct per_cpu_dm_data *hw_data; 1654 1655 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1656 kfree(hw_data->hw_entries); 1657 __net_dm_cpu_data_fini(hw_data); 1658 } 1659 1660 static int __init init_net_drop_monitor(void) 1661 { 1662 int cpu, rc; 1663 1664 pr_info("Initializing network drop monitor service\n"); 1665 1666 if (sizeof(void *) > 8) { 1667 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1668 return -ENOSPC; 1669 } 1670 1671 rc = genl_register_family(&net_drop_monitor_family); 1672 if (rc) { 1673 pr_err("Could not create drop monitor netlink family\n"); 1674 return rc; 1675 } 1676 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1677 1678 rc = register_netdevice_notifier(&dropmon_net_notifier); 1679 if (rc < 0) { 1680 pr_crit("Failed to register netdevice notifier\n"); 1681 goto out_unreg; 1682 } 1683 1684 rc = 0; 1685 1686 for_each_possible_cpu(cpu) { 1687 net_dm_cpu_data_init(cpu); 1688 net_dm_hw_cpu_data_init(cpu); 1689 } 1690 1691 goto out; 1692 1693 out_unreg: 1694 genl_unregister_family(&net_drop_monitor_family); 1695 out: 1696 return rc; 1697 } 1698 1699 static void exit_net_drop_monitor(void) 1700 { 1701 int cpu; 1702 1703 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1704 1705 /* 1706 * Because of the module_get/put we do in the trace state change path 1707 * we are guarnateed not to have any current users when we get here 1708 */ 1709 1710 for_each_possible_cpu(cpu) { 1711 net_dm_hw_cpu_data_fini(cpu); 1712 net_dm_cpu_data_fini(cpu); 1713 } 1714 1715 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1716 } 1717 1718 module_init(init_net_drop_monitor); 1719 module_exit(exit_net_drop_monitor); 1720 1721 MODULE_LICENSE("GPL v2"); 1722 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1723 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1724 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1725