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/bitfield.h> 25 #include <linux/percpu.h> 26 #include <linux/timer.h> 27 #include <linux/bitops.h> 28 #include <linux/slab.h> 29 #include <linux/module.h> 30 #include <net/genetlink.h> 31 #include <net/netevent.h> 32 #include <net/flow_offload.h> 33 #include <net/dropreason.h> 34 #include <net/devlink.h> 35 36 #include <trace/events/skb.h> 37 #include <trace/events/napi.h> 38 #include <trace/events/devlink.h> 39 40 #include <asm/unaligned.h> 41 42 #define TRACE_ON 1 43 #define TRACE_OFF 0 44 45 /* 46 * Globals, our netlink socket pointer 47 * and the work handle that will send up 48 * netlink alerts 49 */ 50 static int trace_state = TRACE_OFF; 51 static bool monitor_hw; 52 53 /* net_dm_mutex 54 * 55 * An overall lock guarding every operation coming from userspace. 56 */ 57 static DEFINE_MUTEX(net_dm_mutex); 58 59 struct net_dm_stats { 60 u64_stats_t dropped; 61 struct u64_stats_sync syncp; 62 }; 63 64 #define NET_DM_MAX_HW_TRAP_NAME_LEN 40 65 66 struct net_dm_hw_entry { 67 char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN]; 68 u32 count; 69 }; 70 71 struct net_dm_hw_entries { 72 u32 num_entries; 73 struct net_dm_hw_entry entries[]; 74 }; 75 76 struct per_cpu_dm_data { 77 spinlock_t lock; /* Protects 'skb', 'hw_entries' and 78 * 'send_timer' 79 */ 80 union { 81 struct sk_buff *skb; 82 struct net_dm_hw_entries *hw_entries; 83 }; 84 struct sk_buff_head drop_queue; 85 struct work_struct dm_alert_work; 86 struct timer_list send_timer; 87 struct net_dm_stats stats; 88 }; 89 90 struct dm_hw_stat_delta { 91 unsigned long last_rx; 92 unsigned long last_drop_val; 93 struct rcu_head rcu; 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; 104 105 static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY; 106 static u32 net_dm_trunc_len; 107 static u32 net_dm_queue_len = 1000; 108 109 struct net_dm_alert_ops { 110 void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb, 111 void *location, 112 enum skb_drop_reason reason); 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_trap_probe)(void *ignore, const struct devlink *devlink, 118 struct sk_buff *skb, 119 const struct devlink_trap_metadata *metadata); 120 }; 121 122 struct net_dm_skb_cb { 123 union { 124 struct devlink_trap_metadata *hw_metadata; 125 void *pc; 126 }; 127 enum skb_drop_reason reason; 128 }; 129 130 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) 131 132 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) 133 { 134 size_t al; 135 struct net_dm_alert_msg *msg; 136 struct nlattr *nla; 137 struct sk_buff *skb; 138 unsigned long flags; 139 void *msg_header; 140 141 al = sizeof(struct net_dm_alert_msg); 142 al += dm_hit_limit * sizeof(struct net_dm_drop_point); 143 al += sizeof(struct nlattr); 144 145 skb = genlmsg_new(al, GFP_KERNEL); 146 147 if (!skb) 148 goto err; 149 150 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family, 151 0, NET_DM_CMD_ALERT); 152 if (!msg_header) { 153 nlmsg_free(skb); 154 skb = NULL; 155 goto err; 156 } 157 nla = nla_reserve(skb, NLA_UNSPEC, 158 sizeof(struct net_dm_alert_msg)); 159 if (!nla) { 160 nlmsg_free(skb); 161 skb = NULL; 162 goto err; 163 } 164 msg = nla_data(nla); 165 memset(msg, 0, al); 166 goto out; 167 168 err: 169 mod_timer(&data->send_timer, jiffies + HZ / 10); 170 out: 171 spin_lock_irqsave(&data->lock, flags); 172 swap(data->skb, skb); 173 spin_unlock_irqrestore(&data->lock, flags); 174 175 if (skb) { 176 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; 177 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh); 178 179 genlmsg_end(skb, genlmsg_data(gnlh)); 180 } 181 182 return skb; 183 } 184 185 static const struct genl_multicast_group dropmon_mcgrps[] = { 186 { .name = "events", }, 187 }; 188 189 static void send_dm_alert(struct work_struct *work) 190 { 191 struct sk_buff *skb; 192 struct per_cpu_dm_data *data; 193 194 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 195 196 skb = reset_per_cpu_data(data); 197 198 if (skb) 199 genlmsg_multicast(&net_drop_monitor_family, skb, 0, 200 0, GFP_KERNEL); 201 } 202 203 /* 204 * This is the timer function to delay the sending of an alert 205 * in the event that more drops will arrive during the 206 * hysteresis period. 207 */ 208 static void sched_send_work(struct timer_list *t) 209 { 210 struct per_cpu_dm_data *data = from_timer(data, t, send_timer); 211 212 schedule_work(&data->dm_alert_work); 213 } 214 215 static void trace_drop_common(struct sk_buff *skb, void *location) 216 { 217 struct net_dm_alert_msg *msg; 218 struct net_dm_drop_point *point; 219 struct nlmsghdr *nlh; 220 struct nlattr *nla; 221 int i; 222 struct sk_buff *dskb; 223 struct per_cpu_dm_data *data; 224 unsigned long flags; 225 226 local_irq_save(flags); 227 data = this_cpu_ptr(&dm_cpu_data); 228 spin_lock(&data->lock); 229 dskb = data->skb; 230 231 if (!dskb) 232 goto out; 233 234 nlh = (struct nlmsghdr *)dskb->data; 235 nla = genlmsg_data(nlmsg_data(nlh)); 236 msg = nla_data(nla); 237 point = msg->points; 238 for (i = 0; i < msg->entries; i++) { 239 if (!memcmp(&location, &point->pc, sizeof(void *))) { 240 point->count++; 241 goto out; 242 } 243 point++; 244 } 245 if (msg->entries == dm_hit_limit) 246 goto out; 247 /* 248 * We need to create a new entry 249 */ 250 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point)); 251 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); 252 memcpy(point->pc, &location, sizeof(void *)); 253 point->count = 1; 254 msg->entries++; 255 256 if (!timer_pending(&data->send_timer)) { 257 data->send_timer.expires = jiffies + dm_delay * HZ; 258 add_timer(&data->send_timer); 259 } 260 261 out: 262 spin_unlock_irqrestore(&data->lock, flags); 263 } 264 265 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, 266 void *location, 267 enum skb_drop_reason reason) 268 { 269 trace_drop_common(skb, location); 270 } 271 272 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, 273 int work, int budget) 274 { 275 struct net_device *dev = napi->dev; 276 struct dm_hw_stat_delta *stat; 277 /* 278 * Don't check napi structures with no associated device 279 */ 280 if (!dev) 281 return; 282 283 rcu_read_lock(); 284 stat = rcu_dereference(dev->dm_private); 285 if (stat) { 286 /* 287 * only add a note to our monitor buffer if: 288 * 1) its after the last_rx delta 289 * 2) our rx_dropped count has gone up 290 */ 291 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) && 292 (dev->stats.rx_dropped != stat->last_drop_val)) { 293 trace_drop_common(NULL, NULL); 294 stat->last_drop_val = dev->stats.rx_dropped; 295 stat->last_rx = jiffies; 296 } 297 } 298 rcu_read_unlock(); 299 } 300 301 static struct net_dm_hw_entries * 302 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data) 303 { 304 struct net_dm_hw_entries *hw_entries; 305 unsigned long flags; 306 307 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit), 308 GFP_KERNEL); 309 if (!hw_entries) { 310 /* If the memory allocation failed, we try to perform another 311 * allocation in 1/10 second. Otherwise, the probe function 312 * will constantly bail out. 313 */ 314 mod_timer(&hw_data->send_timer, jiffies + HZ / 10); 315 } 316 317 spin_lock_irqsave(&hw_data->lock, flags); 318 swap(hw_data->hw_entries, hw_entries); 319 spin_unlock_irqrestore(&hw_data->lock, flags); 320 321 return hw_entries; 322 } 323 324 static int net_dm_hw_entry_put(struct sk_buff *msg, 325 const struct net_dm_hw_entry *hw_entry) 326 { 327 struct nlattr *attr; 328 329 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY); 330 if (!attr) 331 return -EMSGSIZE; 332 333 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name)) 334 goto nla_put_failure; 335 336 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count)) 337 goto nla_put_failure; 338 339 nla_nest_end(msg, attr); 340 341 return 0; 342 343 nla_put_failure: 344 nla_nest_cancel(msg, attr); 345 return -EMSGSIZE; 346 } 347 348 static int net_dm_hw_entries_put(struct sk_buff *msg, 349 const struct net_dm_hw_entries *hw_entries) 350 { 351 struct nlattr *attr; 352 int i; 353 354 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES); 355 if (!attr) 356 return -EMSGSIZE; 357 358 for (i = 0; i < hw_entries->num_entries; i++) { 359 int rc; 360 361 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]); 362 if (rc) 363 goto nla_put_failure; 364 } 365 366 nla_nest_end(msg, attr); 367 368 return 0; 369 370 nla_put_failure: 371 nla_nest_cancel(msg, attr); 372 return -EMSGSIZE; 373 } 374 375 static int 376 net_dm_hw_summary_report_fill(struct sk_buff *msg, 377 const struct net_dm_hw_entries *hw_entries) 378 { 379 struct net_dm_alert_msg anc_hdr = { 0 }; 380 void *hdr; 381 int rc; 382 383 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 384 NET_DM_CMD_ALERT); 385 if (!hdr) 386 return -EMSGSIZE; 387 388 /* We need to put the ancillary header in order not to break user 389 * space. 390 */ 391 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr)) 392 goto nla_put_failure; 393 394 rc = net_dm_hw_entries_put(msg, hw_entries); 395 if (rc) 396 goto nla_put_failure; 397 398 genlmsg_end(msg, hdr); 399 400 return 0; 401 402 nla_put_failure: 403 genlmsg_cancel(msg, hdr); 404 return -EMSGSIZE; 405 } 406 407 static void net_dm_hw_summary_work(struct work_struct *work) 408 { 409 struct net_dm_hw_entries *hw_entries; 410 struct per_cpu_dm_data *hw_data; 411 struct sk_buff *msg; 412 int rc; 413 414 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 415 416 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 417 if (!hw_entries) 418 return; 419 420 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 421 if (!msg) 422 goto out; 423 424 rc = net_dm_hw_summary_report_fill(msg, hw_entries); 425 if (rc) { 426 nlmsg_free(msg); 427 goto out; 428 } 429 430 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 431 432 out: 433 kfree(hw_entries); 434 } 435 436 static void 437 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink, 438 struct sk_buff *skb, 439 const struct devlink_trap_metadata *metadata) 440 { 441 struct net_dm_hw_entries *hw_entries; 442 struct net_dm_hw_entry *hw_entry; 443 struct per_cpu_dm_data *hw_data; 444 unsigned long flags; 445 int i; 446 447 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 448 return; 449 450 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 451 spin_lock_irqsave(&hw_data->lock, flags); 452 hw_entries = hw_data->hw_entries; 453 454 if (!hw_entries) 455 goto out; 456 457 for (i = 0; i < hw_entries->num_entries; i++) { 458 hw_entry = &hw_entries->entries[i]; 459 if (!strncmp(hw_entry->trap_name, metadata->trap_name, 460 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) { 461 hw_entry->count++; 462 goto out; 463 } 464 } 465 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit)) 466 goto out; 467 468 hw_entry = &hw_entries->entries[hw_entries->num_entries]; 469 strscpy(hw_entry->trap_name, metadata->trap_name, 470 NET_DM_MAX_HW_TRAP_NAME_LEN - 1); 471 hw_entry->count = 1; 472 hw_entries->num_entries++; 473 474 if (!timer_pending(&hw_data->send_timer)) { 475 hw_data->send_timer.expires = jiffies + dm_delay * HZ; 476 add_timer(&hw_data->send_timer); 477 } 478 479 out: 480 spin_unlock_irqrestore(&hw_data->lock, flags); 481 } 482 483 static const struct net_dm_alert_ops net_dm_alert_summary_ops = { 484 .kfree_skb_probe = trace_kfree_skb_hit, 485 .napi_poll_probe = trace_napi_poll_hit, 486 .work_item_func = send_dm_alert, 487 .hw_work_item_func = net_dm_hw_summary_work, 488 .hw_trap_probe = net_dm_hw_trap_summary_probe, 489 }; 490 491 static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 492 struct sk_buff *skb, 493 void *location, 494 enum skb_drop_reason reason) 495 { 496 ktime_t tstamp = ktime_get_real(); 497 struct per_cpu_dm_data *data; 498 struct net_dm_skb_cb *cb; 499 struct sk_buff *nskb; 500 unsigned long flags; 501 502 if (!skb_mac_header_was_set(skb)) 503 return; 504 505 nskb = skb_clone(skb, GFP_ATOMIC); 506 if (!nskb) 507 return; 508 509 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 #define NET_DM_MAX_REASON_LEN 50 556 557 static size_t net_dm_packet_report_size(size_t payload_len) 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(NET_DM_MAX_REASON_LEN + 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 const struct drop_reason_list *list = NULL; 614 unsigned int subsys, subsys_reason; 615 char buf[NET_DM_MAX_SYMBOL_LEN]; 616 struct nlattr *attr; 617 void *hdr; 618 int rc; 619 620 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 621 NET_DM_CMD_PACKET_ALERT); 622 if (!hdr) 623 return -EMSGSIZE; 624 625 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 626 goto nla_put_failure; 627 628 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, 629 NET_DM_ATTR_PAD)) 630 goto nla_put_failure; 631 632 rcu_read_lock(); 633 subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK); 634 if (subsys < SKB_DROP_REASON_SUBSYS_NUM) 635 list = rcu_dereference(drop_reasons_by_subsys[subsys]); 636 subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK; 637 if (!list || 638 subsys_reason >= list->n_reasons || 639 !list->reasons[subsys_reason] || 640 strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) { 641 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]); 642 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED; 643 } 644 if (nla_put_string(msg, NET_DM_ATTR_REASON, 645 list->reasons[subsys_reason])) { 646 rcu_read_unlock(); 647 goto nla_put_failure; 648 } 649 rcu_read_unlock(); 650 651 snprintf(buf, sizeof(buf), "%pS", cb->pc); 652 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 653 goto nla_put_failure; 654 655 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 656 if (rc) 657 goto nla_put_failure; 658 659 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 660 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 661 goto nla_put_failure; 662 663 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 664 goto nla_put_failure; 665 666 if (!payload_len) 667 goto out; 668 669 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 670 goto nla_put_failure; 671 672 attr = skb_put(msg, nla_total_size(payload_len)); 673 attr->nla_type = NET_DM_ATTR_PAYLOAD; 674 attr->nla_len = nla_attr_size(payload_len); 675 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 676 goto nla_put_failure; 677 678 out: 679 genlmsg_end(msg, hdr); 680 681 return 0; 682 683 nla_put_failure: 684 genlmsg_cancel(msg, hdr); 685 return -EMSGSIZE; 686 } 687 688 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 689 690 static void net_dm_packet_report(struct sk_buff *skb) 691 { 692 struct sk_buff *msg; 693 size_t payload_len; 694 int rc; 695 696 /* Make sure we start copying the packet from the MAC header */ 697 if (skb->data > skb_mac_header(skb)) 698 skb_push(skb, skb->data - skb_mac_header(skb)); 699 else 700 skb_pull(skb, skb_mac_header(skb) - skb->data); 701 702 /* Ensure packet fits inside a single netlink attribute */ 703 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 704 if (net_dm_trunc_len) 705 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 706 707 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 708 if (!msg) 709 goto out; 710 711 rc = net_dm_packet_report_fill(msg, skb, payload_len); 712 if (rc) { 713 nlmsg_free(msg); 714 goto out; 715 } 716 717 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 718 719 out: 720 consume_skb(skb); 721 } 722 723 static void net_dm_packet_work(struct work_struct *work) 724 { 725 struct per_cpu_dm_data *data; 726 struct sk_buff_head list; 727 struct sk_buff *skb; 728 unsigned long flags; 729 730 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 731 732 __skb_queue_head_init(&list); 733 734 spin_lock_irqsave(&data->drop_queue.lock, flags); 735 skb_queue_splice_tail_init(&data->drop_queue, &list); 736 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 737 738 while ((skb = __skb_dequeue(&list))) 739 net_dm_packet_report(skb); 740 } 741 742 static size_t 743 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) 744 { 745 return hw_metadata->fa_cookie ? 746 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 747 } 748 749 static size_t 750 net_dm_hw_packet_report_size(size_t payload_len, 751 const struct devlink_trap_metadata *hw_metadata) 752 { 753 size_t size; 754 755 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 756 757 return NLMSG_ALIGN(size) + 758 /* NET_DM_ATTR_ORIGIN */ 759 nla_total_size(sizeof(u16)) + 760 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 761 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 762 /* NET_DM_ATTR_HW_TRAP_NAME */ 763 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 764 /* NET_DM_ATTR_IN_PORT */ 765 net_dm_in_port_size() + 766 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 767 net_dm_flow_action_cookie_size(hw_metadata) + 768 /* NET_DM_ATTR_TIMESTAMP */ 769 nla_total_size(sizeof(u64)) + 770 /* NET_DM_ATTR_ORIG_LEN */ 771 nla_total_size(sizeof(u32)) + 772 /* NET_DM_ATTR_PROTO */ 773 nla_total_size(sizeof(u16)) + 774 /* NET_DM_ATTR_PAYLOAD */ 775 nla_total_size(payload_len); 776 } 777 778 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 779 struct sk_buff *skb, size_t payload_len) 780 { 781 struct devlink_trap_metadata *hw_metadata; 782 struct nlattr *attr; 783 void *hdr; 784 785 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 786 787 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 788 NET_DM_CMD_PACKET_ALERT); 789 if (!hdr) 790 return -EMSGSIZE; 791 792 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 793 goto nla_put_failure; 794 795 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 796 hw_metadata->trap_group_name)) 797 goto nla_put_failure; 798 799 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 800 hw_metadata->trap_name)) 801 goto nla_put_failure; 802 803 if (hw_metadata->input_dev) { 804 struct net_device *dev = hw_metadata->input_dev; 805 int rc; 806 807 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 808 dev->name); 809 if (rc) 810 goto nla_put_failure; 811 } 812 813 if (hw_metadata->fa_cookie && 814 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 815 hw_metadata->fa_cookie->cookie_len, 816 hw_metadata->fa_cookie->cookie)) 817 goto nla_put_failure; 818 819 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 820 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 821 goto nla_put_failure; 822 823 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 824 goto nla_put_failure; 825 826 if (!payload_len) 827 goto out; 828 829 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 830 goto nla_put_failure; 831 832 attr = skb_put(msg, nla_total_size(payload_len)); 833 attr->nla_type = NET_DM_ATTR_PAYLOAD; 834 attr->nla_len = nla_attr_size(payload_len); 835 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 836 goto nla_put_failure; 837 838 out: 839 genlmsg_end(msg, hdr); 840 841 return 0; 842 843 nla_put_failure: 844 genlmsg_cancel(msg, hdr); 845 return -EMSGSIZE; 846 } 847 848 static struct devlink_trap_metadata * 849 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) 850 { 851 const struct flow_action_cookie *fa_cookie; 852 struct devlink_trap_metadata *hw_metadata; 853 const char *trap_group_name; 854 const char *trap_name; 855 856 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); 857 if (!hw_metadata) 858 return NULL; 859 860 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); 861 if (!trap_group_name) 862 goto free_hw_metadata; 863 hw_metadata->trap_group_name = trap_group_name; 864 865 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); 866 if (!trap_name) 867 goto free_trap_group; 868 hw_metadata->trap_name = trap_name; 869 870 if (metadata->fa_cookie) { 871 size_t cookie_size = sizeof(*fa_cookie) + 872 metadata->fa_cookie->cookie_len; 873 874 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, 875 GFP_ATOMIC); 876 if (!fa_cookie) 877 goto free_trap_name; 878 hw_metadata->fa_cookie = fa_cookie; 879 } 880 881 hw_metadata->input_dev = metadata->input_dev; 882 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker, 883 GFP_ATOMIC); 884 885 return hw_metadata; 886 887 free_trap_name: 888 kfree(trap_name); 889 free_trap_group: 890 kfree(trap_group_name); 891 free_hw_metadata: 892 kfree(hw_metadata); 893 return NULL; 894 } 895 896 static void 897 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) 898 { 899 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker); 900 kfree(hw_metadata->fa_cookie); 901 kfree(hw_metadata->trap_name); 902 kfree(hw_metadata->trap_group_name); 903 kfree(hw_metadata); 904 } 905 906 static void net_dm_hw_packet_report(struct sk_buff *skb) 907 { 908 struct devlink_trap_metadata *hw_metadata; 909 struct sk_buff *msg; 910 size_t payload_len; 911 int rc; 912 913 if (skb->data > skb_mac_header(skb)) 914 skb_push(skb, skb->data - skb_mac_header(skb)); 915 else 916 skb_pull(skb, skb_mac_header(skb) - skb->data); 917 918 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 919 if (net_dm_trunc_len) 920 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 921 922 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 923 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 924 GFP_KERNEL); 925 if (!msg) 926 goto out; 927 928 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 929 if (rc) { 930 nlmsg_free(msg); 931 goto out; 932 } 933 934 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 935 936 out: 937 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 938 consume_skb(skb); 939 } 940 941 static void net_dm_hw_packet_work(struct work_struct *work) 942 { 943 struct per_cpu_dm_data *hw_data; 944 struct sk_buff_head list; 945 struct sk_buff *skb; 946 unsigned long flags; 947 948 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 949 950 __skb_queue_head_init(&list); 951 952 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 953 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 954 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 955 956 while ((skb = __skb_dequeue(&list))) 957 net_dm_hw_packet_report(skb); 958 } 959 960 static void 961 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink, 962 struct sk_buff *skb, 963 const struct devlink_trap_metadata *metadata) 964 { 965 struct devlink_trap_metadata *n_hw_metadata; 966 ktime_t tstamp = ktime_get_real(); 967 struct per_cpu_dm_data *hw_data; 968 struct sk_buff *nskb; 969 unsigned long flags; 970 971 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 972 return; 973 974 if (!skb_mac_header_was_set(skb)) 975 return; 976 977 nskb = skb_clone(skb, GFP_ATOMIC); 978 if (!nskb) 979 return; 980 981 n_hw_metadata = net_dm_hw_metadata_copy(metadata); 982 if (!n_hw_metadata) 983 goto free; 984 985 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 986 nskb->tstamp = tstamp; 987 988 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 989 990 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 991 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 992 __skb_queue_tail(&hw_data->drop_queue, nskb); 993 else 994 goto unlock_free; 995 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 996 997 schedule_work(&hw_data->dm_alert_work); 998 999 return; 1000 1001 unlock_free: 1002 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 1003 u64_stats_update_begin(&hw_data->stats.syncp); 1004 u64_stats_inc(&hw_data->stats.dropped); 1005 u64_stats_update_end(&hw_data->stats.syncp); 1006 net_dm_hw_metadata_free(n_hw_metadata); 1007 free: 1008 consume_skb(nskb); 1009 } 1010 1011 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 1012 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 1013 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 1014 .work_item_func = net_dm_packet_work, 1015 .hw_work_item_func = net_dm_hw_packet_work, 1016 .hw_trap_probe = net_dm_hw_trap_packet_probe, 1017 }; 1018 1019 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 1020 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 1021 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 1022 }; 1023 1024 #if IS_ENABLED(CONFIG_NET_DEVLINK) 1025 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1026 { 1027 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1028 } 1029 1030 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1031 { 1032 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1033 tracepoint_synchronize_unregister(); 1034 } 1035 #else 1036 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1037 { 1038 return -EOPNOTSUPP; 1039 } 1040 1041 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1042 { 1043 } 1044 #endif 1045 1046 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1047 { 1048 const struct net_dm_alert_ops *ops; 1049 int cpu, rc; 1050 1051 if (monitor_hw) { 1052 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1053 return -EAGAIN; 1054 } 1055 1056 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1057 1058 if (!try_module_get(THIS_MODULE)) { 1059 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1060 return -ENODEV; 1061 } 1062 1063 for_each_possible_cpu(cpu) { 1064 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1065 struct net_dm_hw_entries *hw_entries; 1066 1067 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1068 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1069 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1070 kfree(hw_entries); 1071 } 1072 1073 rc = net_dm_hw_probe_register(ops); 1074 if (rc) { 1075 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); 1076 goto err_module_put; 1077 } 1078 1079 monitor_hw = true; 1080 1081 return 0; 1082 1083 err_module_put: 1084 for_each_possible_cpu(cpu) { 1085 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1086 struct sk_buff *skb; 1087 1088 del_timer_sync(&hw_data->send_timer); 1089 cancel_work_sync(&hw_data->dm_alert_work); 1090 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1091 struct devlink_trap_metadata *hw_metadata; 1092 1093 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1094 net_dm_hw_metadata_free(hw_metadata); 1095 consume_skb(skb); 1096 } 1097 } 1098 module_put(THIS_MODULE); 1099 return rc; 1100 } 1101 1102 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1103 { 1104 const struct net_dm_alert_ops *ops; 1105 int cpu; 1106 1107 if (!monitor_hw) { 1108 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1109 return; 1110 } 1111 1112 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1113 1114 monitor_hw = false; 1115 1116 net_dm_hw_probe_unregister(ops); 1117 1118 for_each_possible_cpu(cpu) { 1119 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1120 struct sk_buff *skb; 1121 1122 del_timer_sync(&hw_data->send_timer); 1123 cancel_work_sync(&hw_data->dm_alert_work); 1124 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1125 struct devlink_trap_metadata *hw_metadata; 1126 1127 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1128 net_dm_hw_metadata_free(hw_metadata); 1129 consume_skb(skb); 1130 } 1131 } 1132 1133 module_put(THIS_MODULE); 1134 } 1135 1136 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1137 { 1138 const struct net_dm_alert_ops *ops; 1139 int cpu, rc; 1140 1141 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1142 1143 if (!try_module_get(THIS_MODULE)) { 1144 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1145 return -ENODEV; 1146 } 1147 1148 for_each_possible_cpu(cpu) { 1149 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1150 struct sk_buff *skb; 1151 1152 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1153 timer_setup(&data->send_timer, sched_send_work, 0); 1154 /* Allocate a new per-CPU skb for the summary alert message and 1155 * free the old one which might contain stale data from 1156 * previous tracing. 1157 */ 1158 skb = reset_per_cpu_data(data); 1159 consume_skb(skb); 1160 } 1161 1162 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1163 if (rc) { 1164 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1165 goto err_module_put; 1166 } 1167 1168 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1169 if (rc) { 1170 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1171 goto err_unregister_trace; 1172 } 1173 1174 return 0; 1175 1176 err_unregister_trace: 1177 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1178 err_module_put: 1179 for_each_possible_cpu(cpu) { 1180 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1181 struct sk_buff *skb; 1182 1183 del_timer_sync(&data->send_timer); 1184 cancel_work_sync(&data->dm_alert_work); 1185 while ((skb = __skb_dequeue(&data->drop_queue))) 1186 consume_skb(skb); 1187 } 1188 module_put(THIS_MODULE); 1189 return rc; 1190 } 1191 1192 static void net_dm_trace_off_set(void) 1193 { 1194 const struct net_dm_alert_ops *ops; 1195 int cpu; 1196 1197 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1198 1199 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1200 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1201 1202 tracepoint_synchronize_unregister(); 1203 1204 /* Make sure we do not send notifications to user space after request 1205 * to stop tracing returns. 1206 */ 1207 for_each_possible_cpu(cpu) { 1208 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1209 struct sk_buff *skb; 1210 1211 del_timer_sync(&data->send_timer); 1212 cancel_work_sync(&data->dm_alert_work); 1213 while ((skb = __skb_dequeue(&data->drop_queue))) 1214 consume_skb(skb); 1215 } 1216 1217 module_put(THIS_MODULE); 1218 } 1219 1220 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1221 { 1222 int rc = 0; 1223 1224 if (state == trace_state) { 1225 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1226 return -EAGAIN; 1227 } 1228 1229 switch (state) { 1230 case TRACE_ON: 1231 rc = net_dm_trace_on_set(extack); 1232 break; 1233 case TRACE_OFF: 1234 net_dm_trace_off_set(); 1235 break; 1236 default: 1237 rc = 1; 1238 break; 1239 } 1240 1241 if (!rc) 1242 trace_state = state; 1243 else 1244 rc = -EINPROGRESS; 1245 1246 return rc; 1247 } 1248 1249 static bool net_dm_is_monitoring(void) 1250 { 1251 return trace_state == TRACE_ON || monitor_hw; 1252 } 1253 1254 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1255 enum net_dm_alert_mode *p_alert_mode) 1256 { 1257 u8 val; 1258 1259 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1260 1261 switch (val) { 1262 case NET_DM_ALERT_MODE_SUMMARY: 1263 case NET_DM_ALERT_MODE_PACKET: 1264 *p_alert_mode = val; 1265 break; 1266 default: 1267 return -EINVAL; 1268 } 1269 1270 return 0; 1271 } 1272 1273 static int net_dm_alert_mode_set(struct genl_info *info) 1274 { 1275 struct netlink_ext_ack *extack = info->extack; 1276 enum net_dm_alert_mode alert_mode; 1277 int rc; 1278 1279 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1280 return 0; 1281 1282 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1283 if (rc) { 1284 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1285 return -EINVAL; 1286 } 1287 1288 net_dm_alert_mode = alert_mode; 1289 1290 return 0; 1291 } 1292 1293 static void net_dm_trunc_len_set(struct genl_info *info) 1294 { 1295 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1296 return; 1297 1298 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1299 } 1300 1301 static void net_dm_queue_len_set(struct genl_info *info) 1302 { 1303 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1304 return; 1305 1306 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1307 } 1308 1309 static int net_dm_cmd_config(struct sk_buff *skb, 1310 struct genl_info *info) 1311 { 1312 struct netlink_ext_ack *extack = info->extack; 1313 int rc; 1314 1315 if (net_dm_is_monitoring()) { 1316 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1317 return -EBUSY; 1318 } 1319 1320 rc = net_dm_alert_mode_set(info); 1321 if (rc) 1322 return rc; 1323 1324 net_dm_trunc_len_set(info); 1325 1326 net_dm_queue_len_set(info); 1327 1328 return 0; 1329 } 1330 1331 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1332 struct netlink_ext_ack *extack) 1333 { 1334 bool sw_set = false; 1335 int rc; 1336 1337 if (set_sw) { 1338 rc = set_all_monitor_traces(TRACE_ON, extack); 1339 if (rc) 1340 return rc; 1341 sw_set = true; 1342 } 1343 1344 if (set_hw) { 1345 rc = net_dm_hw_monitor_start(extack); 1346 if (rc) 1347 goto err_monitor_hw; 1348 } 1349 1350 return 0; 1351 1352 err_monitor_hw: 1353 if (sw_set) 1354 set_all_monitor_traces(TRACE_OFF, extack); 1355 return rc; 1356 } 1357 1358 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1359 struct netlink_ext_ack *extack) 1360 { 1361 if (set_hw) 1362 net_dm_hw_monitor_stop(extack); 1363 if (set_sw) 1364 set_all_monitor_traces(TRACE_OFF, extack); 1365 } 1366 1367 static int net_dm_cmd_trace(struct sk_buff *skb, 1368 struct genl_info *info) 1369 { 1370 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1371 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1372 struct netlink_ext_ack *extack = info->extack; 1373 1374 /* To maintain backward compatibility, we start / stop monitoring of 1375 * software drops if no flag is specified. 1376 */ 1377 if (!set_sw && !set_hw) 1378 set_sw = true; 1379 1380 switch (info->genlhdr->cmd) { 1381 case NET_DM_CMD_START: 1382 return net_dm_monitor_start(set_sw, set_hw, extack); 1383 case NET_DM_CMD_STOP: 1384 net_dm_monitor_stop(set_sw, set_hw, extack); 1385 return 0; 1386 } 1387 1388 return -EOPNOTSUPP; 1389 } 1390 1391 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1392 { 1393 void *hdr; 1394 1395 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1396 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1397 if (!hdr) 1398 return -EMSGSIZE; 1399 1400 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1401 goto nla_put_failure; 1402 1403 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1404 goto nla_put_failure; 1405 1406 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1407 goto nla_put_failure; 1408 1409 genlmsg_end(msg, hdr); 1410 1411 return 0; 1412 1413 nla_put_failure: 1414 genlmsg_cancel(msg, hdr); 1415 return -EMSGSIZE; 1416 } 1417 1418 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1419 { 1420 struct sk_buff *msg; 1421 int rc; 1422 1423 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1424 if (!msg) 1425 return -ENOMEM; 1426 1427 rc = net_dm_config_fill(msg, info); 1428 if (rc) 1429 goto free_msg; 1430 1431 return genlmsg_reply(msg, info); 1432 1433 free_msg: 1434 nlmsg_free(msg); 1435 return rc; 1436 } 1437 1438 static void net_dm_stats_read(struct net_dm_stats *stats) 1439 { 1440 int cpu; 1441 1442 memset(stats, 0, sizeof(*stats)); 1443 for_each_possible_cpu(cpu) { 1444 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1445 struct net_dm_stats *cpu_stats = &data->stats; 1446 unsigned int start; 1447 u64 dropped; 1448 1449 do { 1450 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1451 dropped = u64_stats_read(&cpu_stats->dropped); 1452 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1453 1454 u64_stats_add(&stats->dropped, dropped); 1455 } 1456 } 1457 1458 static int net_dm_stats_put(struct sk_buff *msg) 1459 { 1460 struct net_dm_stats stats; 1461 struct nlattr *attr; 1462 1463 net_dm_stats_read(&stats); 1464 1465 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1466 if (!attr) 1467 return -EMSGSIZE; 1468 1469 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1470 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1471 goto nla_put_failure; 1472 1473 nla_nest_end(msg, attr); 1474 1475 return 0; 1476 1477 nla_put_failure: 1478 nla_nest_cancel(msg, attr); 1479 return -EMSGSIZE; 1480 } 1481 1482 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1483 { 1484 int cpu; 1485 1486 memset(stats, 0, sizeof(*stats)); 1487 for_each_possible_cpu(cpu) { 1488 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1489 struct net_dm_stats *cpu_stats = &hw_data->stats; 1490 unsigned int start; 1491 u64 dropped; 1492 1493 do { 1494 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1495 dropped = u64_stats_read(&cpu_stats->dropped); 1496 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1497 1498 u64_stats_add(&stats->dropped, dropped); 1499 } 1500 } 1501 1502 static int net_dm_hw_stats_put(struct sk_buff *msg) 1503 { 1504 struct net_dm_stats stats; 1505 struct nlattr *attr; 1506 1507 net_dm_hw_stats_read(&stats); 1508 1509 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1510 if (!attr) 1511 return -EMSGSIZE; 1512 1513 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1514 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1515 goto nla_put_failure; 1516 1517 nla_nest_end(msg, attr); 1518 1519 return 0; 1520 1521 nla_put_failure: 1522 nla_nest_cancel(msg, attr); 1523 return -EMSGSIZE; 1524 } 1525 1526 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1527 { 1528 void *hdr; 1529 int rc; 1530 1531 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1532 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1533 if (!hdr) 1534 return -EMSGSIZE; 1535 1536 rc = net_dm_stats_put(msg); 1537 if (rc) 1538 goto nla_put_failure; 1539 1540 rc = net_dm_hw_stats_put(msg); 1541 if (rc) 1542 goto nla_put_failure; 1543 1544 genlmsg_end(msg, hdr); 1545 1546 return 0; 1547 1548 nla_put_failure: 1549 genlmsg_cancel(msg, hdr); 1550 return -EMSGSIZE; 1551 } 1552 1553 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1554 { 1555 struct sk_buff *msg; 1556 int rc; 1557 1558 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1559 if (!msg) 1560 return -ENOMEM; 1561 1562 rc = net_dm_stats_fill(msg, info); 1563 if (rc) 1564 goto free_msg; 1565 1566 return genlmsg_reply(msg, info); 1567 1568 free_msg: 1569 nlmsg_free(msg); 1570 return rc; 1571 } 1572 1573 static int dropmon_net_event(struct notifier_block *ev_block, 1574 unsigned long event, void *ptr) 1575 { 1576 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1577 struct dm_hw_stat_delta *stat; 1578 1579 switch (event) { 1580 case NETDEV_REGISTER: 1581 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private))) 1582 break; 1583 stat = kzalloc(sizeof(*stat), GFP_KERNEL); 1584 if (!stat) 1585 break; 1586 1587 stat->last_rx = jiffies; 1588 rcu_assign_pointer(dev->dm_private, stat); 1589 1590 break; 1591 case NETDEV_UNREGISTER: 1592 stat = rtnl_dereference(dev->dm_private); 1593 if (stat) { 1594 rcu_assign_pointer(dev->dm_private, NULL); 1595 kfree_rcu(stat, rcu); 1596 } 1597 break; 1598 } 1599 return NOTIFY_DONE; 1600 } 1601 1602 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1603 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1604 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1605 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1606 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1607 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1608 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1609 }; 1610 1611 static const struct genl_small_ops dropmon_ops[] = { 1612 { 1613 .cmd = NET_DM_CMD_CONFIG, 1614 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1615 .doit = net_dm_cmd_config, 1616 .flags = GENL_ADMIN_PERM, 1617 }, 1618 { 1619 .cmd = NET_DM_CMD_START, 1620 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1621 .doit = net_dm_cmd_trace, 1622 }, 1623 { 1624 .cmd = NET_DM_CMD_STOP, 1625 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1626 .doit = net_dm_cmd_trace, 1627 }, 1628 { 1629 .cmd = NET_DM_CMD_CONFIG_GET, 1630 .doit = net_dm_cmd_config_get, 1631 }, 1632 { 1633 .cmd = NET_DM_CMD_STATS_GET, 1634 .doit = net_dm_cmd_stats_get, 1635 }, 1636 }; 1637 1638 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops, 1639 struct sk_buff *skb, struct genl_info *info) 1640 { 1641 mutex_lock(&net_dm_mutex); 1642 1643 return 0; 1644 } 1645 1646 static void net_dm_nl_post_doit(const struct genl_split_ops *ops, 1647 struct sk_buff *skb, struct genl_info *info) 1648 { 1649 mutex_unlock(&net_dm_mutex); 1650 } 1651 1652 static struct genl_family net_drop_monitor_family __ro_after_init = { 1653 .hdrsize = 0, 1654 .name = "NET_DM", 1655 .version = 2, 1656 .maxattr = NET_DM_ATTR_MAX, 1657 .policy = net_dm_nl_policy, 1658 .pre_doit = net_dm_nl_pre_doit, 1659 .post_doit = net_dm_nl_post_doit, 1660 .module = THIS_MODULE, 1661 .small_ops = dropmon_ops, 1662 .n_small_ops = ARRAY_SIZE(dropmon_ops), 1663 .resv_start_op = NET_DM_CMD_STATS_GET + 1, 1664 .mcgrps = dropmon_mcgrps, 1665 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1666 }; 1667 1668 static struct notifier_block dropmon_net_notifier = { 1669 .notifier_call = dropmon_net_event 1670 }; 1671 1672 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1673 { 1674 spin_lock_init(&data->lock); 1675 skb_queue_head_init(&data->drop_queue); 1676 u64_stats_init(&data->stats.syncp); 1677 } 1678 1679 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1680 { 1681 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1682 } 1683 1684 static void net_dm_cpu_data_init(int cpu) 1685 { 1686 struct per_cpu_dm_data *data; 1687 1688 data = &per_cpu(dm_cpu_data, cpu); 1689 __net_dm_cpu_data_init(data); 1690 } 1691 1692 static void net_dm_cpu_data_fini(int cpu) 1693 { 1694 struct per_cpu_dm_data *data; 1695 1696 data = &per_cpu(dm_cpu_data, cpu); 1697 /* At this point, we should have exclusive access 1698 * to this struct and can free the skb inside it. 1699 */ 1700 consume_skb(data->skb); 1701 __net_dm_cpu_data_fini(data); 1702 } 1703 1704 static void net_dm_hw_cpu_data_init(int cpu) 1705 { 1706 struct per_cpu_dm_data *hw_data; 1707 1708 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1709 __net_dm_cpu_data_init(hw_data); 1710 } 1711 1712 static void net_dm_hw_cpu_data_fini(int cpu) 1713 { 1714 struct per_cpu_dm_data *hw_data; 1715 1716 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1717 kfree(hw_data->hw_entries); 1718 __net_dm_cpu_data_fini(hw_data); 1719 } 1720 1721 static int __init init_net_drop_monitor(void) 1722 { 1723 int cpu, rc; 1724 1725 pr_info("Initializing network drop monitor service\n"); 1726 1727 if (sizeof(void *) > 8) { 1728 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1729 return -ENOSPC; 1730 } 1731 1732 rc = genl_register_family(&net_drop_monitor_family); 1733 if (rc) { 1734 pr_err("Could not create drop monitor netlink family\n"); 1735 return rc; 1736 } 1737 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1738 1739 rc = register_netdevice_notifier(&dropmon_net_notifier); 1740 if (rc < 0) { 1741 pr_crit("Failed to register netdevice notifier\n"); 1742 goto out_unreg; 1743 } 1744 1745 rc = 0; 1746 1747 for_each_possible_cpu(cpu) { 1748 net_dm_cpu_data_init(cpu); 1749 net_dm_hw_cpu_data_init(cpu); 1750 } 1751 1752 goto out; 1753 1754 out_unreg: 1755 genl_unregister_family(&net_drop_monitor_family); 1756 out: 1757 return rc; 1758 } 1759 1760 static void exit_net_drop_monitor(void) 1761 { 1762 int cpu; 1763 1764 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1765 1766 /* 1767 * Because of the module_get/put we do in the trace state change path 1768 * we are guaranteed not to have any current users when we get here 1769 */ 1770 1771 for_each_possible_cpu(cpu) { 1772 net_dm_hw_cpu_data_fini(cpu); 1773 net_dm_cpu_data_fini(cpu); 1774 } 1775 1776 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1777 } 1778 1779 module_init(init_net_drop_monitor); 1780 module_exit(exit_net_drop_monitor); 1781 1782 MODULE_LICENSE("GPL v2"); 1783 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1784 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1785 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1786