1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Monitoring code for network dropped packet alerts 4 * 5 * Copyright (C) 2009 Neil Horman <nhorman@tuxdriver.com> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/netdevice.h> 11 #include <linux/etherdevice.h> 12 #include <linux/string.h> 13 #include <linux/if_arp.h> 14 #include <linux/inetdevice.h> 15 #include <linux/inet.h> 16 #include <linux/interrupt.h> 17 #include <linux/netpoll.h> 18 #include <linux/sched.h> 19 #include <linux/delay.h> 20 #include <linux/types.h> 21 #include <linux/workqueue.h> 22 #include <linux/netlink.h> 23 #include <linux/net_dropmon.h> 24 #include <linux/percpu.h> 25 #include <linux/timer.h> 26 #include <linux/bitops.h> 27 #include <linux/slab.h> 28 #include <linux/module.h> 29 #include <net/genetlink.h> 30 #include <net/netevent.h> 31 #include <net/flow_offload.h> 32 #include <net/devlink.h> 33 34 #include <trace/events/skb.h> 35 #include <trace/events/napi.h> 36 #include <trace/events/devlink.h> 37 38 #include <asm/unaligned.h> 39 40 #define TRACE_ON 1 41 #define TRACE_OFF 0 42 43 /* 44 * Globals, our netlink socket pointer 45 * and the work handle that will send up 46 * netlink alerts 47 */ 48 static int trace_state = TRACE_OFF; 49 static bool monitor_hw; 50 51 /* net_dm_mutex 52 * 53 * An overall lock guarding every operation coming from userspace. 54 */ 55 static DEFINE_MUTEX(net_dm_mutex); 56 57 struct net_dm_stats { 58 u64_stats_t 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 unsigned long last_rx; 90 unsigned long last_drop_val; 91 struct rcu_head rcu; 92 }; 93 94 static struct genl_family net_drop_monitor_family; 95 96 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); 97 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data); 98 99 static int dm_hit_limit = 64; 100 static int dm_delay = 1; 101 static unsigned long dm_hw_check_delta = 2*HZ; 102 103 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY; 104 static u32 net_dm_trunc_len; 105 static u32 net_dm_queue_len = 1000; 106 107 struct net_dm_alert_ops { 108 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, 109 void *location, 110 enum skb_drop_reason reason); 111 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi, 112 int work, int budget); 113 void (*work_item_func)(struct work_struct *work); 114 void (*hw_work_item_func)(struct work_struct *work); 115 void (*hw_trap_probe)(void *ignore, const struct devlink *devlink, 116 struct sk_buff *skb, 117 const struct devlink_trap_metadata *metadata); 118 }; 119 120 struct net_dm_skb_cb { 121 union { 122 struct devlink_trap_metadata *hw_metadata; 123 void *pc; 124 }; 125 enum skb_drop_reason reason; 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, 264 void *location, 265 enum skb_drop_reason reason) 266 { 267 trace_drop_common(skb, location); 268 } 269 270 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, 271 int work, int budget) 272 { 273 struct net_device *dev = napi->dev; 274 struct dm_hw_stat_delta *stat; 275 /* 276 * Don't check napi structures with no associated device 277 */ 278 if (!dev) 279 return; 280 281 rcu_read_lock(); 282 stat = rcu_dereference(dev->dm_private); 283 if (stat) { 284 /* 285 * only add a note to our monitor buffer if: 286 * 1) its after the last_rx delta 287 * 2) our rx_dropped count has gone up 288 */ 289 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) && 290 (dev->stats.rx_dropped != stat->last_drop_val)) { 291 trace_drop_common(NULL, NULL); 292 stat->last_drop_val = dev->stats.rx_dropped; 293 stat->last_rx = jiffies; 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_trap_summary_probe(void *ignore, const struct devlink *devlink, 436 struct sk_buff *skb, 437 const struct devlink_trap_metadata *metadata) 438 { 439 struct net_dm_hw_entries *hw_entries; 440 struct net_dm_hw_entry *hw_entry; 441 struct per_cpu_dm_data *hw_data; 442 unsigned long flags; 443 int i; 444 445 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 446 return; 447 448 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 449 spin_lock_irqsave(&hw_data->lock, flags); 450 hw_entries = hw_data->hw_entries; 451 452 if (!hw_entries) 453 goto out; 454 455 for (i = 0; i < hw_entries->num_entries; i++) { 456 hw_entry = &hw_entries->entries[i]; 457 if (!strncmp(hw_entry->trap_name, metadata->trap_name, 458 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) { 459 hw_entry->count++; 460 goto out; 461 } 462 } 463 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit)) 464 goto out; 465 466 hw_entry = &hw_entries->entries[hw_entries->num_entries]; 467 strscpy(hw_entry->trap_name, metadata->trap_name, 468 NET_DM_MAX_HW_TRAP_NAME_LEN - 1); 469 hw_entry->count = 1; 470 hw_entries->num_entries++; 471 472 if (!timer_pending(&hw_data->send_timer)) { 473 hw_data->send_timer.expires = jiffies + dm_delay * HZ; 474 add_timer(&hw_data->send_timer); 475 } 476 477 out: 478 spin_unlock_irqrestore(&hw_data->lock, flags); 479 } 480 481 static const struct net_dm_alert_ops net_dm_alert_summary_ops = { 482 .kfree_skb_probe = trace_kfree_skb_hit, 483 .napi_poll_probe = trace_napi_poll_hit, 484 .work_item_func = send_dm_alert, 485 .hw_work_item_func = net_dm_hw_summary_work, 486 .hw_trap_probe = net_dm_hw_trap_summary_probe, 487 }; 488 489 static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 490 struct sk_buff *skb, 491 void *location, 492 enum skb_drop_reason reason) 493 { 494 ktime_t tstamp = ktime_get_real(); 495 struct per_cpu_dm_data *data; 496 struct net_dm_skb_cb *cb; 497 struct sk_buff *nskb; 498 unsigned long flags; 499 500 if (!skb_mac_header_was_set(skb)) 501 return; 502 503 nskb = skb_clone(skb, GFP_ATOMIC); 504 if (!nskb) 505 return; 506 507 if (unlikely(reason >= SKB_DROP_REASON_MAX || reason <= 0)) 508 reason = SKB_DROP_REASON_NOT_SPECIFIED; 509 cb = NET_DM_SKB_CB(nskb); 510 cb->reason = reason; 511 cb->pc = location; 512 /* Override the timestamp because we care about the time when the 513 * packet was dropped. 514 */ 515 nskb->tstamp = tstamp; 516 517 data = this_cpu_ptr(&dm_cpu_data); 518 519 spin_lock_irqsave(&data->drop_queue.lock, flags); 520 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 521 __skb_queue_tail(&data->drop_queue, nskb); 522 else 523 goto unlock_free; 524 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 525 526 schedule_work(&data->dm_alert_work); 527 528 return; 529 530 unlock_free: 531 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 532 u64_stats_update_begin(&data->stats.syncp); 533 u64_stats_inc(&data->stats.dropped); 534 u64_stats_update_end(&data->stats.syncp); 535 consume_skb(nskb); 536 } 537 538 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 539 struct napi_struct *napi, 540 int work, int budget) 541 { 542 } 543 544 static size_t net_dm_in_port_size(void) 545 { 546 /* NET_DM_ATTR_IN_PORT nest */ 547 return nla_total_size(0) + 548 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 549 nla_total_size(sizeof(u32)) + 550 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 551 nla_total_size(IFNAMSIZ + 1); 552 } 553 554 #define NET_DM_MAX_SYMBOL_LEN 40 555 556 static size_t net_dm_packet_report_size(size_t payload_len, 557 enum skb_drop_reason reason) 558 { 559 size_t size; 560 561 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 562 563 return NLMSG_ALIGN(size) + 564 /* NET_DM_ATTR_ORIGIN */ 565 nla_total_size(sizeof(u16)) + 566 /* NET_DM_ATTR_PC */ 567 nla_total_size(sizeof(u64)) + 568 /* NET_DM_ATTR_SYMBOL */ 569 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 570 /* NET_DM_ATTR_IN_PORT */ 571 net_dm_in_port_size() + 572 /* NET_DM_ATTR_TIMESTAMP */ 573 nla_total_size(sizeof(u64)) + 574 /* NET_DM_ATTR_ORIG_LEN */ 575 nla_total_size(sizeof(u32)) + 576 /* NET_DM_ATTR_PROTO */ 577 nla_total_size(sizeof(u16)) + 578 /* NET_DM_ATTR_REASON */ 579 nla_total_size(strlen(drop_reasons[reason]) + 1) + 580 /* NET_DM_ATTR_PAYLOAD */ 581 nla_total_size(payload_len); 582 } 583 584 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 585 const char *name) 586 { 587 struct nlattr *attr; 588 589 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 590 if (!attr) 591 return -EMSGSIZE; 592 593 if (ifindex && 594 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 595 goto nla_put_failure; 596 597 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 598 goto nla_put_failure; 599 600 nla_nest_end(msg, attr); 601 602 return 0; 603 604 nla_put_failure: 605 nla_nest_cancel(msg, attr); 606 return -EMSGSIZE; 607 } 608 609 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 610 size_t payload_len) 611 { 612 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); 613 char buf[NET_DM_MAX_SYMBOL_LEN]; 614 struct nlattr *attr; 615 void *hdr; 616 int rc; 617 618 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 619 NET_DM_CMD_PACKET_ALERT); 620 if (!hdr) 621 return -EMSGSIZE; 622 623 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 624 goto nla_put_failure; 625 626 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, 627 NET_DM_ATTR_PAD)) 628 goto nla_put_failure; 629 630 if (nla_put_string(msg, NET_DM_ATTR_REASON, 631 drop_reasons[cb->reason])) 632 goto nla_put_failure; 633 634 snprintf(buf, sizeof(buf), "%pS", cb->pc); 635 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 636 goto nla_put_failure; 637 638 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 639 if (rc) 640 goto nla_put_failure; 641 642 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 643 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 644 goto nla_put_failure; 645 646 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 647 goto nla_put_failure; 648 649 if (!payload_len) 650 goto out; 651 652 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 653 goto nla_put_failure; 654 655 attr = skb_put(msg, nla_total_size(payload_len)); 656 attr->nla_type = NET_DM_ATTR_PAYLOAD; 657 attr->nla_len = nla_attr_size(payload_len); 658 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 659 goto nla_put_failure; 660 661 out: 662 genlmsg_end(msg, hdr); 663 664 return 0; 665 666 nla_put_failure: 667 genlmsg_cancel(msg, hdr); 668 return -EMSGSIZE; 669 } 670 671 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 672 673 static void net_dm_packet_report(struct sk_buff *skb) 674 { 675 struct sk_buff *msg; 676 size_t payload_len; 677 int rc; 678 679 /* Make sure we start copying the packet from the MAC header */ 680 if (skb->data > skb_mac_header(skb)) 681 skb_push(skb, skb->data - skb_mac_header(skb)); 682 else 683 skb_pull(skb, skb_mac_header(skb) - skb->data); 684 685 /* Ensure packet fits inside a single netlink attribute */ 686 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 687 if (net_dm_trunc_len) 688 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 689 690 msg = nlmsg_new(net_dm_packet_report_size(payload_len, 691 NET_DM_SKB_CB(skb)->reason), 692 GFP_KERNEL); 693 if (!msg) 694 goto out; 695 696 rc = net_dm_packet_report_fill(msg, skb, payload_len); 697 if (rc) { 698 nlmsg_free(msg); 699 goto out; 700 } 701 702 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 703 704 out: 705 consume_skb(skb); 706 } 707 708 static void net_dm_packet_work(struct work_struct *work) 709 { 710 struct per_cpu_dm_data *data; 711 struct sk_buff_head list; 712 struct sk_buff *skb; 713 unsigned long flags; 714 715 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 716 717 __skb_queue_head_init(&list); 718 719 spin_lock_irqsave(&data->drop_queue.lock, flags); 720 skb_queue_splice_tail_init(&data->drop_queue, &list); 721 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 722 723 while ((skb = __skb_dequeue(&list))) 724 net_dm_packet_report(skb); 725 } 726 727 static size_t 728 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) 729 { 730 return hw_metadata->fa_cookie ? 731 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 732 } 733 734 static size_t 735 net_dm_hw_packet_report_size(size_t payload_len, 736 const struct devlink_trap_metadata *hw_metadata) 737 { 738 size_t size; 739 740 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 741 742 return NLMSG_ALIGN(size) + 743 /* NET_DM_ATTR_ORIGIN */ 744 nla_total_size(sizeof(u16)) + 745 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 746 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 747 /* NET_DM_ATTR_HW_TRAP_NAME */ 748 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 749 /* NET_DM_ATTR_IN_PORT */ 750 net_dm_in_port_size() + 751 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 752 net_dm_flow_action_cookie_size(hw_metadata) + 753 /* NET_DM_ATTR_TIMESTAMP */ 754 nla_total_size(sizeof(u64)) + 755 /* NET_DM_ATTR_ORIG_LEN */ 756 nla_total_size(sizeof(u32)) + 757 /* NET_DM_ATTR_PROTO */ 758 nla_total_size(sizeof(u16)) + 759 /* NET_DM_ATTR_PAYLOAD */ 760 nla_total_size(payload_len); 761 } 762 763 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 764 struct sk_buff *skb, size_t payload_len) 765 { 766 struct devlink_trap_metadata *hw_metadata; 767 struct nlattr *attr; 768 void *hdr; 769 770 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 771 772 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 773 NET_DM_CMD_PACKET_ALERT); 774 if (!hdr) 775 return -EMSGSIZE; 776 777 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 778 goto nla_put_failure; 779 780 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 781 hw_metadata->trap_group_name)) 782 goto nla_put_failure; 783 784 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 785 hw_metadata->trap_name)) 786 goto nla_put_failure; 787 788 if (hw_metadata->input_dev) { 789 struct net_device *dev = hw_metadata->input_dev; 790 int rc; 791 792 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 793 dev->name); 794 if (rc) 795 goto nla_put_failure; 796 } 797 798 if (hw_metadata->fa_cookie && 799 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 800 hw_metadata->fa_cookie->cookie_len, 801 hw_metadata->fa_cookie->cookie)) 802 goto nla_put_failure; 803 804 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 805 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 806 goto nla_put_failure; 807 808 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 809 goto nla_put_failure; 810 811 if (!payload_len) 812 goto out; 813 814 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 815 goto nla_put_failure; 816 817 attr = skb_put(msg, nla_total_size(payload_len)); 818 attr->nla_type = NET_DM_ATTR_PAYLOAD; 819 attr->nla_len = nla_attr_size(payload_len); 820 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 821 goto nla_put_failure; 822 823 out: 824 genlmsg_end(msg, hdr); 825 826 return 0; 827 828 nla_put_failure: 829 genlmsg_cancel(msg, hdr); 830 return -EMSGSIZE; 831 } 832 833 static struct devlink_trap_metadata * 834 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) 835 { 836 const struct flow_action_cookie *fa_cookie; 837 struct devlink_trap_metadata *hw_metadata; 838 const char *trap_group_name; 839 const char *trap_name; 840 841 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); 842 if (!hw_metadata) 843 return NULL; 844 845 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); 846 if (!trap_group_name) 847 goto free_hw_metadata; 848 hw_metadata->trap_group_name = trap_group_name; 849 850 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); 851 if (!trap_name) 852 goto free_trap_group; 853 hw_metadata->trap_name = trap_name; 854 855 if (metadata->fa_cookie) { 856 size_t cookie_size = sizeof(*fa_cookie) + 857 metadata->fa_cookie->cookie_len; 858 859 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, 860 GFP_ATOMIC); 861 if (!fa_cookie) 862 goto free_trap_name; 863 hw_metadata->fa_cookie = fa_cookie; 864 } 865 866 hw_metadata->input_dev = metadata->input_dev; 867 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker, 868 GFP_ATOMIC); 869 870 return hw_metadata; 871 872 free_trap_name: 873 kfree(trap_name); 874 free_trap_group: 875 kfree(trap_group_name); 876 free_hw_metadata: 877 kfree(hw_metadata); 878 return NULL; 879 } 880 881 static void 882 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) 883 { 884 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker); 885 kfree(hw_metadata->fa_cookie); 886 kfree(hw_metadata->trap_name); 887 kfree(hw_metadata->trap_group_name); 888 kfree(hw_metadata); 889 } 890 891 static void net_dm_hw_packet_report(struct sk_buff *skb) 892 { 893 struct devlink_trap_metadata *hw_metadata; 894 struct sk_buff *msg; 895 size_t payload_len; 896 int rc; 897 898 if (skb->data > skb_mac_header(skb)) 899 skb_push(skb, skb->data - skb_mac_header(skb)); 900 else 901 skb_pull(skb, skb_mac_header(skb) - skb->data); 902 903 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 904 if (net_dm_trunc_len) 905 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 906 907 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 908 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 909 GFP_KERNEL); 910 if (!msg) 911 goto out; 912 913 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 914 if (rc) { 915 nlmsg_free(msg); 916 goto out; 917 } 918 919 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 920 921 out: 922 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 923 consume_skb(skb); 924 } 925 926 static void net_dm_hw_packet_work(struct work_struct *work) 927 { 928 struct per_cpu_dm_data *hw_data; 929 struct sk_buff_head list; 930 struct sk_buff *skb; 931 unsigned long flags; 932 933 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 934 935 __skb_queue_head_init(&list); 936 937 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 938 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 939 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 940 941 while ((skb = __skb_dequeue(&list))) 942 net_dm_hw_packet_report(skb); 943 } 944 945 static void 946 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink, 947 struct sk_buff *skb, 948 const struct devlink_trap_metadata *metadata) 949 { 950 struct devlink_trap_metadata *n_hw_metadata; 951 ktime_t tstamp = ktime_get_real(); 952 struct per_cpu_dm_data *hw_data; 953 struct sk_buff *nskb; 954 unsigned long flags; 955 956 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 957 return; 958 959 if (!skb_mac_header_was_set(skb)) 960 return; 961 962 nskb = skb_clone(skb, GFP_ATOMIC); 963 if (!nskb) 964 return; 965 966 n_hw_metadata = net_dm_hw_metadata_copy(metadata); 967 if (!n_hw_metadata) 968 goto free; 969 970 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 971 nskb->tstamp = tstamp; 972 973 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 974 975 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 976 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 977 __skb_queue_tail(&hw_data->drop_queue, nskb); 978 else 979 goto unlock_free; 980 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 981 982 schedule_work(&hw_data->dm_alert_work); 983 984 return; 985 986 unlock_free: 987 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 988 u64_stats_update_begin(&hw_data->stats.syncp); 989 u64_stats_inc(&hw_data->stats.dropped); 990 u64_stats_update_end(&hw_data->stats.syncp); 991 net_dm_hw_metadata_free(n_hw_metadata); 992 free: 993 consume_skb(nskb); 994 } 995 996 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 997 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 998 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 999 .work_item_func = net_dm_packet_work, 1000 .hw_work_item_func = net_dm_hw_packet_work, 1001 .hw_trap_probe = net_dm_hw_trap_packet_probe, 1002 }; 1003 1004 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 1005 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 1006 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 1007 }; 1008 1009 #if IS_ENABLED(CONFIG_NET_DEVLINK) 1010 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1011 { 1012 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1013 } 1014 1015 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1016 { 1017 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1018 tracepoint_synchronize_unregister(); 1019 } 1020 #else 1021 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1022 { 1023 return -EOPNOTSUPP; 1024 } 1025 1026 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1027 { 1028 } 1029 #endif 1030 1031 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1032 { 1033 const struct net_dm_alert_ops *ops; 1034 int cpu, rc; 1035 1036 if (monitor_hw) { 1037 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1038 return -EAGAIN; 1039 } 1040 1041 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1042 1043 if (!try_module_get(THIS_MODULE)) { 1044 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1045 return -ENODEV; 1046 } 1047 1048 for_each_possible_cpu(cpu) { 1049 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1050 struct net_dm_hw_entries *hw_entries; 1051 1052 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1053 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1054 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1055 kfree(hw_entries); 1056 } 1057 1058 rc = net_dm_hw_probe_register(ops); 1059 if (rc) { 1060 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); 1061 goto err_module_put; 1062 } 1063 1064 monitor_hw = true; 1065 1066 return 0; 1067 1068 err_module_put: 1069 for_each_possible_cpu(cpu) { 1070 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1071 struct sk_buff *skb; 1072 1073 del_timer_sync(&hw_data->send_timer); 1074 cancel_work_sync(&hw_data->dm_alert_work); 1075 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1076 struct devlink_trap_metadata *hw_metadata; 1077 1078 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1079 net_dm_hw_metadata_free(hw_metadata); 1080 consume_skb(skb); 1081 } 1082 } 1083 module_put(THIS_MODULE); 1084 return rc; 1085 } 1086 1087 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1088 { 1089 const struct net_dm_alert_ops *ops; 1090 int cpu; 1091 1092 if (!monitor_hw) { 1093 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1094 return; 1095 } 1096 1097 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1098 1099 monitor_hw = false; 1100 1101 net_dm_hw_probe_unregister(ops); 1102 1103 for_each_possible_cpu(cpu) { 1104 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1105 struct sk_buff *skb; 1106 1107 del_timer_sync(&hw_data->send_timer); 1108 cancel_work_sync(&hw_data->dm_alert_work); 1109 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1110 struct devlink_trap_metadata *hw_metadata; 1111 1112 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1113 net_dm_hw_metadata_free(hw_metadata); 1114 consume_skb(skb); 1115 } 1116 } 1117 1118 module_put(THIS_MODULE); 1119 } 1120 1121 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1122 { 1123 const struct net_dm_alert_ops *ops; 1124 int cpu, rc; 1125 1126 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1127 1128 if (!try_module_get(THIS_MODULE)) { 1129 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1130 return -ENODEV; 1131 } 1132 1133 for_each_possible_cpu(cpu) { 1134 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1135 struct sk_buff *skb; 1136 1137 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1138 timer_setup(&data->send_timer, sched_send_work, 0); 1139 /* Allocate a new per-CPU skb for the summary alert message and 1140 * free the old one which might contain stale data from 1141 * previous tracing. 1142 */ 1143 skb = reset_per_cpu_data(data); 1144 consume_skb(skb); 1145 } 1146 1147 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1148 if (rc) { 1149 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1150 goto err_module_put; 1151 } 1152 1153 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1154 if (rc) { 1155 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1156 goto err_unregister_trace; 1157 } 1158 1159 return 0; 1160 1161 err_unregister_trace: 1162 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1163 err_module_put: 1164 for_each_possible_cpu(cpu) { 1165 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1166 struct sk_buff *skb; 1167 1168 del_timer_sync(&data->send_timer); 1169 cancel_work_sync(&data->dm_alert_work); 1170 while ((skb = __skb_dequeue(&data->drop_queue))) 1171 consume_skb(skb); 1172 } 1173 module_put(THIS_MODULE); 1174 return rc; 1175 } 1176 1177 static void net_dm_trace_off_set(void) 1178 { 1179 const struct net_dm_alert_ops *ops; 1180 int cpu; 1181 1182 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1183 1184 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1185 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1186 1187 tracepoint_synchronize_unregister(); 1188 1189 /* Make sure we do not send notifications to user space after request 1190 * to stop tracing returns. 1191 */ 1192 for_each_possible_cpu(cpu) { 1193 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1194 struct sk_buff *skb; 1195 1196 del_timer_sync(&data->send_timer); 1197 cancel_work_sync(&data->dm_alert_work); 1198 while ((skb = __skb_dequeue(&data->drop_queue))) 1199 consume_skb(skb); 1200 } 1201 1202 module_put(THIS_MODULE); 1203 } 1204 1205 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1206 { 1207 int rc = 0; 1208 1209 if (state == trace_state) { 1210 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1211 return -EAGAIN; 1212 } 1213 1214 switch (state) { 1215 case TRACE_ON: 1216 rc = net_dm_trace_on_set(extack); 1217 break; 1218 case TRACE_OFF: 1219 net_dm_trace_off_set(); 1220 break; 1221 default: 1222 rc = 1; 1223 break; 1224 } 1225 1226 if (!rc) 1227 trace_state = state; 1228 else 1229 rc = -EINPROGRESS; 1230 1231 return rc; 1232 } 1233 1234 static bool net_dm_is_monitoring(void) 1235 { 1236 return trace_state == TRACE_ON || monitor_hw; 1237 } 1238 1239 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1240 enum net_dm_alert_mode *p_alert_mode) 1241 { 1242 u8 val; 1243 1244 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1245 1246 switch (val) { 1247 case NET_DM_ALERT_MODE_SUMMARY: 1248 case NET_DM_ALERT_MODE_PACKET: 1249 *p_alert_mode = val; 1250 break; 1251 default: 1252 return -EINVAL; 1253 } 1254 1255 return 0; 1256 } 1257 1258 static int net_dm_alert_mode_set(struct genl_info *info) 1259 { 1260 struct netlink_ext_ack *extack = info->extack; 1261 enum net_dm_alert_mode alert_mode; 1262 int rc; 1263 1264 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1265 return 0; 1266 1267 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1268 if (rc) { 1269 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1270 return -EINVAL; 1271 } 1272 1273 net_dm_alert_mode = alert_mode; 1274 1275 return 0; 1276 } 1277 1278 static void net_dm_trunc_len_set(struct genl_info *info) 1279 { 1280 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1281 return; 1282 1283 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1284 } 1285 1286 static void net_dm_queue_len_set(struct genl_info *info) 1287 { 1288 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1289 return; 1290 1291 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1292 } 1293 1294 static int net_dm_cmd_config(struct sk_buff *skb, 1295 struct genl_info *info) 1296 { 1297 struct netlink_ext_ack *extack = info->extack; 1298 int rc; 1299 1300 if (net_dm_is_monitoring()) { 1301 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1302 return -EBUSY; 1303 } 1304 1305 rc = net_dm_alert_mode_set(info); 1306 if (rc) 1307 return rc; 1308 1309 net_dm_trunc_len_set(info); 1310 1311 net_dm_queue_len_set(info); 1312 1313 return 0; 1314 } 1315 1316 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1317 struct netlink_ext_ack *extack) 1318 { 1319 bool sw_set = false; 1320 int rc; 1321 1322 if (set_sw) { 1323 rc = set_all_monitor_traces(TRACE_ON, extack); 1324 if (rc) 1325 return rc; 1326 sw_set = true; 1327 } 1328 1329 if (set_hw) { 1330 rc = net_dm_hw_monitor_start(extack); 1331 if (rc) 1332 goto err_monitor_hw; 1333 } 1334 1335 return 0; 1336 1337 err_monitor_hw: 1338 if (sw_set) 1339 set_all_monitor_traces(TRACE_OFF, extack); 1340 return rc; 1341 } 1342 1343 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1344 struct netlink_ext_ack *extack) 1345 { 1346 if (set_hw) 1347 net_dm_hw_monitor_stop(extack); 1348 if (set_sw) 1349 set_all_monitor_traces(TRACE_OFF, extack); 1350 } 1351 1352 static int net_dm_cmd_trace(struct sk_buff *skb, 1353 struct genl_info *info) 1354 { 1355 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1356 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1357 struct netlink_ext_ack *extack = info->extack; 1358 1359 /* To maintain backward compatibility, we start / stop monitoring of 1360 * software drops if no flag is specified. 1361 */ 1362 if (!set_sw && !set_hw) 1363 set_sw = true; 1364 1365 switch (info->genlhdr->cmd) { 1366 case NET_DM_CMD_START: 1367 return net_dm_monitor_start(set_sw, set_hw, extack); 1368 case NET_DM_CMD_STOP: 1369 net_dm_monitor_stop(set_sw, set_hw, extack); 1370 return 0; 1371 } 1372 1373 return -EOPNOTSUPP; 1374 } 1375 1376 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1377 { 1378 void *hdr; 1379 1380 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1381 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1382 if (!hdr) 1383 return -EMSGSIZE; 1384 1385 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1386 goto nla_put_failure; 1387 1388 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1389 goto nla_put_failure; 1390 1391 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1392 goto nla_put_failure; 1393 1394 genlmsg_end(msg, hdr); 1395 1396 return 0; 1397 1398 nla_put_failure: 1399 genlmsg_cancel(msg, hdr); 1400 return -EMSGSIZE; 1401 } 1402 1403 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1404 { 1405 struct sk_buff *msg; 1406 int rc; 1407 1408 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1409 if (!msg) 1410 return -ENOMEM; 1411 1412 rc = net_dm_config_fill(msg, info); 1413 if (rc) 1414 goto free_msg; 1415 1416 return genlmsg_reply(msg, info); 1417 1418 free_msg: 1419 nlmsg_free(msg); 1420 return rc; 1421 } 1422 1423 static void net_dm_stats_read(struct net_dm_stats *stats) 1424 { 1425 int cpu; 1426 1427 memset(stats, 0, sizeof(*stats)); 1428 for_each_possible_cpu(cpu) { 1429 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1430 struct net_dm_stats *cpu_stats = &data->stats; 1431 unsigned int start; 1432 u64 dropped; 1433 1434 do { 1435 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1436 dropped = u64_stats_read(&cpu_stats->dropped); 1437 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1438 1439 u64_stats_add(&stats->dropped, dropped); 1440 } 1441 } 1442 1443 static int net_dm_stats_put(struct sk_buff *msg) 1444 { 1445 struct net_dm_stats stats; 1446 struct nlattr *attr; 1447 1448 net_dm_stats_read(&stats); 1449 1450 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1451 if (!attr) 1452 return -EMSGSIZE; 1453 1454 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1455 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1456 goto nla_put_failure; 1457 1458 nla_nest_end(msg, attr); 1459 1460 return 0; 1461 1462 nla_put_failure: 1463 nla_nest_cancel(msg, attr); 1464 return -EMSGSIZE; 1465 } 1466 1467 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1468 { 1469 int cpu; 1470 1471 memset(stats, 0, sizeof(*stats)); 1472 for_each_possible_cpu(cpu) { 1473 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1474 struct net_dm_stats *cpu_stats = &hw_data->stats; 1475 unsigned int start; 1476 u64 dropped; 1477 1478 do { 1479 start = u64_stats_fetch_begin_irq(&cpu_stats->syncp); 1480 dropped = u64_stats_read(&cpu_stats->dropped); 1481 } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start)); 1482 1483 u64_stats_add(&stats->dropped, dropped); 1484 } 1485 } 1486 1487 static int net_dm_hw_stats_put(struct sk_buff *msg) 1488 { 1489 struct net_dm_stats stats; 1490 struct nlattr *attr; 1491 1492 net_dm_hw_stats_read(&stats); 1493 1494 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1495 if (!attr) 1496 return -EMSGSIZE; 1497 1498 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1499 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1500 goto nla_put_failure; 1501 1502 nla_nest_end(msg, attr); 1503 1504 return 0; 1505 1506 nla_put_failure: 1507 nla_nest_cancel(msg, attr); 1508 return -EMSGSIZE; 1509 } 1510 1511 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1512 { 1513 void *hdr; 1514 int rc; 1515 1516 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1517 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1518 if (!hdr) 1519 return -EMSGSIZE; 1520 1521 rc = net_dm_stats_put(msg); 1522 if (rc) 1523 goto nla_put_failure; 1524 1525 rc = net_dm_hw_stats_put(msg); 1526 if (rc) 1527 goto nla_put_failure; 1528 1529 genlmsg_end(msg, hdr); 1530 1531 return 0; 1532 1533 nla_put_failure: 1534 genlmsg_cancel(msg, hdr); 1535 return -EMSGSIZE; 1536 } 1537 1538 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1539 { 1540 struct sk_buff *msg; 1541 int rc; 1542 1543 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1544 if (!msg) 1545 return -ENOMEM; 1546 1547 rc = net_dm_stats_fill(msg, info); 1548 if (rc) 1549 goto free_msg; 1550 1551 return genlmsg_reply(msg, info); 1552 1553 free_msg: 1554 nlmsg_free(msg); 1555 return rc; 1556 } 1557 1558 static int dropmon_net_event(struct notifier_block *ev_block, 1559 unsigned long event, void *ptr) 1560 { 1561 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1562 struct dm_hw_stat_delta *stat; 1563 1564 switch (event) { 1565 case NETDEV_REGISTER: 1566 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private))) 1567 break; 1568 stat = kzalloc(sizeof(*stat), GFP_KERNEL); 1569 if (!stat) 1570 break; 1571 1572 stat->last_rx = jiffies; 1573 rcu_assign_pointer(dev->dm_private, stat); 1574 1575 break; 1576 case NETDEV_UNREGISTER: 1577 stat = rtnl_dereference(dev->dm_private); 1578 if (stat) { 1579 rcu_assign_pointer(dev->dm_private, NULL); 1580 kfree_rcu(stat, rcu); 1581 } 1582 break; 1583 } 1584 return NOTIFY_DONE; 1585 } 1586 1587 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1588 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1589 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1590 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1591 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1592 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1593 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1594 }; 1595 1596 static const struct genl_small_ops dropmon_ops[] = { 1597 { 1598 .cmd = NET_DM_CMD_CONFIG, 1599 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1600 .doit = net_dm_cmd_config, 1601 .flags = GENL_ADMIN_PERM, 1602 }, 1603 { 1604 .cmd = NET_DM_CMD_START, 1605 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1606 .doit = net_dm_cmd_trace, 1607 }, 1608 { 1609 .cmd = NET_DM_CMD_STOP, 1610 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1611 .doit = net_dm_cmd_trace, 1612 }, 1613 { 1614 .cmd = NET_DM_CMD_CONFIG_GET, 1615 .doit = net_dm_cmd_config_get, 1616 }, 1617 { 1618 .cmd = NET_DM_CMD_STATS_GET, 1619 .doit = net_dm_cmd_stats_get, 1620 }, 1621 }; 1622 1623 static int net_dm_nl_pre_doit(const struct genl_ops *ops, 1624 struct sk_buff *skb, struct genl_info *info) 1625 { 1626 mutex_lock(&net_dm_mutex); 1627 1628 return 0; 1629 } 1630 1631 static void net_dm_nl_post_doit(const struct genl_ops *ops, 1632 struct sk_buff *skb, struct genl_info *info) 1633 { 1634 mutex_unlock(&net_dm_mutex); 1635 } 1636 1637 static struct genl_family net_drop_monitor_family __ro_after_init = { 1638 .hdrsize = 0, 1639 .name = "NET_DM", 1640 .version = 2, 1641 .maxattr = NET_DM_ATTR_MAX, 1642 .policy = net_dm_nl_policy, 1643 .pre_doit = net_dm_nl_pre_doit, 1644 .post_doit = net_dm_nl_post_doit, 1645 .module = THIS_MODULE, 1646 .small_ops = dropmon_ops, 1647 .n_small_ops = ARRAY_SIZE(dropmon_ops), 1648 .resv_start_op = NET_DM_CMD_STATS_GET + 1, 1649 .mcgrps = dropmon_mcgrps, 1650 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1651 }; 1652 1653 static struct notifier_block dropmon_net_notifier = { 1654 .notifier_call = dropmon_net_event 1655 }; 1656 1657 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1658 { 1659 spin_lock_init(&data->lock); 1660 skb_queue_head_init(&data->drop_queue); 1661 u64_stats_init(&data->stats.syncp); 1662 } 1663 1664 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1665 { 1666 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1667 } 1668 1669 static void net_dm_cpu_data_init(int cpu) 1670 { 1671 struct per_cpu_dm_data *data; 1672 1673 data = &per_cpu(dm_cpu_data, cpu); 1674 __net_dm_cpu_data_init(data); 1675 } 1676 1677 static void net_dm_cpu_data_fini(int cpu) 1678 { 1679 struct per_cpu_dm_data *data; 1680 1681 data = &per_cpu(dm_cpu_data, cpu); 1682 /* At this point, we should have exclusive access 1683 * to this struct and can free the skb inside it. 1684 */ 1685 consume_skb(data->skb); 1686 __net_dm_cpu_data_fini(data); 1687 } 1688 1689 static void net_dm_hw_cpu_data_init(int cpu) 1690 { 1691 struct per_cpu_dm_data *hw_data; 1692 1693 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1694 __net_dm_cpu_data_init(hw_data); 1695 } 1696 1697 static void net_dm_hw_cpu_data_fini(int cpu) 1698 { 1699 struct per_cpu_dm_data *hw_data; 1700 1701 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1702 kfree(hw_data->hw_entries); 1703 __net_dm_cpu_data_fini(hw_data); 1704 } 1705 1706 static int __init init_net_drop_monitor(void) 1707 { 1708 int cpu, rc; 1709 1710 pr_info("Initializing network drop monitor service\n"); 1711 1712 if (sizeof(void *) > 8) { 1713 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1714 return -ENOSPC; 1715 } 1716 1717 rc = genl_register_family(&net_drop_monitor_family); 1718 if (rc) { 1719 pr_err("Could not create drop monitor netlink family\n"); 1720 return rc; 1721 } 1722 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1723 1724 rc = register_netdevice_notifier(&dropmon_net_notifier); 1725 if (rc < 0) { 1726 pr_crit("Failed to register netdevice notifier\n"); 1727 goto out_unreg; 1728 } 1729 1730 rc = 0; 1731 1732 for_each_possible_cpu(cpu) { 1733 net_dm_cpu_data_init(cpu); 1734 net_dm_hw_cpu_data_init(cpu); 1735 } 1736 1737 goto out; 1738 1739 out_unreg: 1740 genl_unregister_family(&net_drop_monitor_family); 1741 out: 1742 return rc; 1743 } 1744 1745 static void exit_net_drop_monitor(void) 1746 { 1747 int cpu; 1748 1749 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1750 1751 /* 1752 * Because of the module_get/put we do in the trace state change path 1753 * we are guaranteed not to have any current users when we get here 1754 */ 1755 1756 for_each_possible_cpu(cpu) { 1757 net_dm_hw_cpu_data_fini(cpu); 1758 net_dm_cpu_data_fini(cpu); 1759 } 1760 1761 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1762 } 1763 1764 module_init(init_net_drop_monitor); 1765 module_exit(exit_net_drop_monitor); 1766 1767 MODULE_LICENSE("GPL v2"); 1768 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1769 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1770 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1771