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 raw_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 struct sock *rx_sk); 114 void (*napi_poll_probe)(void *ignore, struct napi_struct *napi, 115 int work, int budget); 116 void (*work_item_func)(struct work_struct *work); 117 void (*hw_work_item_func)(struct work_struct *work); 118 void (*hw_trap_probe)(void *ignore, const struct devlink *devlink, 119 struct sk_buff *skb, 120 const struct devlink_trap_metadata *metadata); 121 }; 122 123 struct net_dm_skb_cb { 124 union { 125 struct devlink_trap_metadata *hw_metadata; 126 void *pc; 127 }; 128 enum skb_drop_reason reason; 129 }; 130 131 #define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0])) 132 133 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) 134 { 135 size_t al; 136 struct net_dm_alert_msg *msg; 137 struct nlattr *nla; 138 struct sk_buff *skb; 139 unsigned long flags; 140 void *msg_header; 141 142 al = sizeof(struct net_dm_alert_msg); 143 al += dm_hit_limit * sizeof(struct net_dm_drop_point); 144 al += sizeof(struct nlattr); 145 146 skb = genlmsg_new(al, GFP_KERNEL); 147 148 if (!skb) 149 goto err; 150 151 msg_header = genlmsg_put(skb, 0, 0, &net_drop_monitor_family, 152 0, NET_DM_CMD_ALERT); 153 if (!msg_header) { 154 nlmsg_free(skb); 155 skb = NULL; 156 goto err; 157 } 158 nla = nla_reserve(skb, NLA_UNSPEC, 159 sizeof(struct net_dm_alert_msg)); 160 if (!nla) { 161 nlmsg_free(skb); 162 skb = NULL; 163 goto err; 164 } 165 msg = nla_data(nla); 166 memset(msg, 0, al); 167 goto out; 168 169 err: 170 mod_timer(&data->send_timer, jiffies + HZ / 10); 171 out: 172 raw_spin_lock_irqsave(&data->lock, flags); 173 swap(data->skb, skb); 174 raw_spin_unlock_irqrestore(&data->lock, flags); 175 176 if (skb) { 177 struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data; 178 struct genlmsghdr *gnlh = (struct genlmsghdr *)nlmsg_data(nlh); 179 180 genlmsg_end(skb, genlmsg_data(gnlh)); 181 } 182 183 return skb; 184 } 185 186 static const struct genl_multicast_group dropmon_mcgrps[] = { 187 { .name = "events", .flags = GENL_MCAST_CAP_SYS_ADMIN, }, 188 }; 189 190 static void send_dm_alert(struct work_struct *work) 191 { 192 struct sk_buff *skb; 193 struct per_cpu_dm_data *data; 194 195 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 196 197 skb = reset_per_cpu_data(data); 198 199 if (skb) 200 genlmsg_multicast(&net_drop_monitor_family, skb, 0, 201 0, GFP_KERNEL); 202 } 203 204 /* 205 * This is the timer function to delay the sending of an alert 206 * in the event that more drops will arrive during the 207 * hysteresis period. 208 */ 209 static void sched_send_work(struct timer_list *t) 210 { 211 struct per_cpu_dm_data *data = from_timer(data, t, send_timer); 212 213 schedule_work(&data->dm_alert_work); 214 } 215 216 static void trace_drop_common(struct sk_buff *skb, void *location) 217 { 218 struct net_dm_alert_msg *msg; 219 struct net_dm_drop_point *point; 220 struct nlmsghdr *nlh; 221 struct nlattr *nla; 222 int i; 223 struct sk_buff *dskb; 224 struct per_cpu_dm_data *data; 225 unsigned long flags; 226 227 local_irq_save(flags); 228 data = this_cpu_ptr(&dm_cpu_data); 229 raw_spin_lock(&data->lock); 230 dskb = data->skb; 231 232 if (!dskb) 233 goto out; 234 235 nlh = (struct nlmsghdr *)dskb->data; 236 nla = genlmsg_data(nlmsg_data(nlh)); 237 msg = nla_data(nla); 238 point = msg->points; 239 for (i = 0; i < msg->entries; i++) { 240 if (!memcmp(&location, &point->pc, sizeof(void *))) { 241 point->count++; 242 goto out; 243 } 244 point++; 245 } 246 if (msg->entries == dm_hit_limit) 247 goto out; 248 /* 249 * We need to create a new entry 250 */ 251 __nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point)); 252 nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point)); 253 memcpy(point->pc, &location, sizeof(void *)); 254 point->count = 1; 255 msg->entries++; 256 257 if (!timer_pending(&data->send_timer)) { 258 data->send_timer.expires = jiffies + dm_delay * HZ; 259 add_timer(&data->send_timer); 260 } 261 262 out: 263 raw_spin_unlock_irqrestore(&data->lock, flags); 264 } 265 266 static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, 267 void *location, 268 enum skb_drop_reason reason, 269 struct sock *rx_sk) 270 { 271 trace_drop_common(skb, location); 272 } 273 274 static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi, 275 int work, int budget) 276 { 277 struct net_device *dev = napi->dev; 278 struct dm_hw_stat_delta *stat; 279 /* 280 * Don't check napi structures with no associated device 281 */ 282 if (!dev) 283 return; 284 285 rcu_read_lock(); 286 stat = rcu_dereference(dev->dm_private); 287 if (stat) { 288 /* 289 * only add a note to our monitor buffer if: 290 * 1) its after the last_rx delta 291 * 2) our rx_dropped count has gone up 292 */ 293 if (time_after(jiffies, stat->last_rx + dm_hw_check_delta) && 294 (dev->stats.rx_dropped != stat->last_drop_val)) { 295 trace_drop_common(NULL, NULL); 296 stat->last_drop_val = dev->stats.rx_dropped; 297 stat->last_rx = jiffies; 298 } 299 } 300 rcu_read_unlock(); 301 } 302 303 static struct net_dm_hw_entries * 304 net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data) 305 { 306 struct net_dm_hw_entries *hw_entries; 307 unsigned long flags; 308 309 hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit), 310 GFP_KERNEL); 311 if (!hw_entries) { 312 /* If the memory allocation failed, we try to perform another 313 * allocation in 1/10 second. Otherwise, the probe function 314 * will constantly bail out. 315 */ 316 mod_timer(&hw_data->send_timer, jiffies + HZ / 10); 317 } 318 319 raw_spin_lock_irqsave(&hw_data->lock, flags); 320 swap(hw_data->hw_entries, hw_entries); 321 raw_spin_unlock_irqrestore(&hw_data->lock, flags); 322 323 return hw_entries; 324 } 325 326 static int net_dm_hw_entry_put(struct sk_buff *msg, 327 const struct net_dm_hw_entry *hw_entry) 328 { 329 struct nlattr *attr; 330 331 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY); 332 if (!attr) 333 return -EMSGSIZE; 334 335 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name)) 336 goto nla_put_failure; 337 338 if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count)) 339 goto nla_put_failure; 340 341 nla_nest_end(msg, attr); 342 343 return 0; 344 345 nla_put_failure: 346 nla_nest_cancel(msg, attr); 347 return -EMSGSIZE; 348 } 349 350 static int net_dm_hw_entries_put(struct sk_buff *msg, 351 const struct net_dm_hw_entries *hw_entries) 352 { 353 struct nlattr *attr; 354 int i; 355 356 attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES); 357 if (!attr) 358 return -EMSGSIZE; 359 360 for (i = 0; i < hw_entries->num_entries; i++) { 361 int rc; 362 363 rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]); 364 if (rc) 365 goto nla_put_failure; 366 } 367 368 nla_nest_end(msg, attr); 369 370 return 0; 371 372 nla_put_failure: 373 nla_nest_cancel(msg, attr); 374 return -EMSGSIZE; 375 } 376 377 static int 378 net_dm_hw_summary_report_fill(struct sk_buff *msg, 379 const struct net_dm_hw_entries *hw_entries) 380 { 381 struct net_dm_alert_msg anc_hdr = { 0 }; 382 void *hdr; 383 int rc; 384 385 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 386 NET_DM_CMD_ALERT); 387 if (!hdr) 388 return -EMSGSIZE; 389 390 /* We need to put the ancillary header in order not to break user 391 * space. 392 */ 393 if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr)) 394 goto nla_put_failure; 395 396 rc = net_dm_hw_entries_put(msg, hw_entries); 397 if (rc) 398 goto nla_put_failure; 399 400 genlmsg_end(msg, hdr); 401 402 return 0; 403 404 nla_put_failure: 405 genlmsg_cancel(msg, hdr); 406 return -EMSGSIZE; 407 } 408 409 static void net_dm_hw_summary_work(struct work_struct *work) 410 { 411 struct net_dm_hw_entries *hw_entries; 412 struct per_cpu_dm_data *hw_data; 413 struct sk_buff *msg; 414 int rc; 415 416 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 417 418 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 419 if (!hw_entries) 420 return; 421 422 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 423 if (!msg) 424 goto out; 425 426 rc = net_dm_hw_summary_report_fill(msg, hw_entries); 427 if (rc) { 428 nlmsg_free(msg); 429 goto out; 430 } 431 432 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 433 434 out: 435 kfree(hw_entries); 436 } 437 438 static void 439 net_dm_hw_trap_summary_probe(void *ignore, const struct devlink *devlink, 440 struct sk_buff *skb, 441 const struct devlink_trap_metadata *metadata) 442 { 443 struct net_dm_hw_entries *hw_entries; 444 struct net_dm_hw_entry *hw_entry; 445 struct per_cpu_dm_data *hw_data; 446 unsigned long flags; 447 int i; 448 449 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 450 return; 451 452 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 453 raw_spin_lock_irqsave(&hw_data->lock, flags); 454 hw_entries = hw_data->hw_entries; 455 456 if (!hw_entries) 457 goto out; 458 459 for (i = 0; i < hw_entries->num_entries; i++) { 460 hw_entry = &hw_entries->entries[i]; 461 if (!strncmp(hw_entry->trap_name, metadata->trap_name, 462 NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) { 463 hw_entry->count++; 464 goto out; 465 } 466 } 467 if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit)) 468 goto out; 469 470 hw_entry = &hw_entries->entries[hw_entries->num_entries]; 471 strscpy(hw_entry->trap_name, metadata->trap_name, 472 NET_DM_MAX_HW_TRAP_NAME_LEN - 1); 473 hw_entry->count = 1; 474 hw_entries->num_entries++; 475 476 if (!timer_pending(&hw_data->send_timer)) { 477 hw_data->send_timer.expires = jiffies + dm_delay * HZ; 478 add_timer(&hw_data->send_timer); 479 } 480 481 out: 482 raw_spin_unlock_irqrestore(&hw_data->lock, flags); 483 } 484 485 static const struct net_dm_alert_ops net_dm_alert_summary_ops = { 486 .kfree_skb_probe = trace_kfree_skb_hit, 487 .napi_poll_probe = trace_napi_poll_hit, 488 .work_item_func = send_dm_alert, 489 .hw_work_item_func = net_dm_hw_summary_work, 490 .hw_trap_probe = net_dm_hw_trap_summary_probe, 491 }; 492 493 static void net_dm_packet_trace_kfree_skb_hit(void *ignore, 494 struct sk_buff *skb, 495 void *location, 496 enum skb_drop_reason reason, 497 struct sock *rx_sk) 498 { 499 ktime_t tstamp = ktime_get_real(); 500 struct per_cpu_dm_data *data; 501 struct net_dm_skb_cb *cb; 502 struct sk_buff *nskb; 503 unsigned long flags; 504 505 if (!skb_mac_header_was_set(skb)) 506 return; 507 508 nskb = skb_clone(skb, GFP_ATOMIC); 509 if (!nskb) 510 return; 511 512 cb = NET_DM_SKB_CB(nskb); 513 cb->reason = reason; 514 cb->pc = location; 515 /* Override the timestamp because we care about the time when the 516 * packet was dropped. 517 */ 518 nskb->tstamp = tstamp; 519 520 data = this_cpu_ptr(&dm_cpu_data); 521 522 spin_lock_irqsave(&data->drop_queue.lock, flags); 523 if (skb_queue_len(&data->drop_queue) < net_dm_queue_len) 524 __skb_queue_tail(&data->drop_queue, nskb); 525 else 526 goto unlock_free; 527 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 528 529 schedule_work(&data->dm_alert_work); 530 531 return; 532 533 unlock_free: 534 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 535 u64_stats_update_begin(&data->stats.syncp); 536 u64_stats_inc(&data->stats.dropped); 537 u64_stats_update_end(&data->stats.syncp); 538 consume_skb(nskb); 539 } 540 541 static void net_dm_packet_trace_napi_poll_hit(void *ignore, 542 struct napi_struct *napi, 543 int work, int budget) 544 { 545 } 546 547 static size_t net_dm_in_port_size(void) 548 { 549 /* NET_DM_ATTR_IN_PORT nest */ 550 return nla_total_size(0) + 551 /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */ 552 nla_total_size(sizeof(u32)) + 553 /* NET_DM_ATTR_PORT_NETDEV_NAME */ 554 nla_total_size(IFNAMSIZ + 1); 555 } 556 557 #define NET_DM_MAX_SYMBOL_LEN 40 558 #define NET_DM_MAX_REASON_LEN 50 559 560 static size_t net_dm_packet_report_size(size_t payload_len) 561 { 562 size_t size; 563 564 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 565 566 return NLMSG_ALIGN(size) + 567 /* NET_DM_ATTR_ORIGIN */ 568 nla_total_size(sizeof(u16)) + 569 /* NET_DM_ATTR_PC */ 570 nla_total_size(sizeof(u64)) + 571 /* NET_DM_ATTR_SYMBOL */ 572 nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + 573 /* NET_DM_ATTR_IN_PORT */ 574 net_dm_in_port_size() + 575 /* NET_DM_ATTR_TIMESTAMP */ 576 nla_total_size(sizeof(u64)) + 577 /* NET_DM_ATTR_ORIG_LEN */ 578 nla_total_size(sizeof(u32)) + 579 /* NET_DM_ATTR_PROTO */ 580 nla_total_size(sizeof(u16)) + 581 /* NET_DM_ATTR_REASON */ 582 nla_total_size(NET_DM_MAX_REASON_LEN + 1) + 583 /* NET_DM_ATTR_PAYLOAD */ 584 nla_total_size(payload_len); 585 } 586 587 static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex, 588 const char *name) 589 { 590 struct nlattr *attr; 591 592 attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT); 593 if (!attr) 594 return -EMSGSIZE; 595 596 if (ifindex && 597 nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex)) 598 goto nla_put_failure; 599 600 if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name)) 601 goto nla_put_failure; 602 603 nla_nest_end(msg, attr); 604 605 return 0; 606 607 nla_put_failure: 608 nla_nest_cancel(msg, attr); 609 return -EMSGSIZE; 610 } 611 612 static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb, 613 size_t payload_len) 614 { 615 struct net_dm_skb_cb *cb = NET_DM_SKB_CB(skb); 616 const struct drop_reason_list *list = NULL; 617 unsigned int subsys, subsys_reason; 618 char buf[NET_DM_MAX_SYMBOL_LEN]; 619 struct nlattr *attr; 620 void *hdr; 621 int rc; 622 623 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 624 NET_DM_CMD_PACKET_ALERT); 625 if (!hdr) 626 return -EMSGSIZE; 627 628 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW)) 629 goto nla_put_failure; 630 631 if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, (u64)(uintptr_t)cb->pc, 632 NET_DM_ATTR_PAD)) 633 goto nla_put_failure; 634 635 rcu_read_lock(); 636 subsys = u32_get_bits(cb->reason, SKB_DROP_REASON_SUBSYS_MASK); 637 if (subsys < SKB_DROP_REASON_SUBSYS_NUM) 638 list = rcu_dereference(drop_reasons_by_subsys[subsys]); 639 subsys_reason = cb->reason & ~SKB_DROP_REASON_SUBSYS_MASK; 640 if (!list || 641 subsys_reason >= list->n_reasons || 642 !list->reasons[subsys_reason] || 643 strlen(list->reasons[subsys_reason]) > NET_DM_MAX_REASON_LEN) { 644 list = rcu_dereference(drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_CORE]); 645 subsys_reason = SKB_DROP_REASON_NOT_SPECIFIED; 646 } 647 if (nla_put_string(msg, NET_DM_ATTR_REASON, 648 list->reasons[subsys_reason])) { 649 rcu_read_unlock(); 650 goto nla_put_failure; 651 } 652 rcu_read_unlock(); 653 654 snprintf(buf, sizeof(buf), "%pS", cb->pc); 655 if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf)) 656 goto nla_put_failure; 657 658 rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL); 659 if (rc) 660 goto nla_put_failure; 661 662 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 663 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 664 goto nla_put_failure; 665 666 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 667 goto nla_put_failure; 668 669 if (!payload_len) 670 goto out; 671 672 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 673 goto nla_put_failure; 674 675 attr = skb_put(msg, nla_total_size(payload_len)); 676 attr->nla_type = NET_DM_ATTR_PAYLOAD; 677 attr->nla_len = nla_attr_size(payload_len); 678 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 679 goto nla_put_failure; 680 681 out: 682 genlmsg_end(msg, hdr); 683 684 return 0; 685 686 nla_put_failure: 687 genlmsg_cancel(msg, hdr); 688 return -EMSGSIZE; 689 } 690 691 #define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO) 692 693 static void net_dm_packet_report(struct sk_buff *skb) 694 { 695 struct sk_buff *msg; 696 size_t payload_len; 697 int rc; 698 699 /* Make sure we start copying the packet from the MAC header */ 700 if (skb->data > skb_mac_header(skb)) 701 skb_push(skb, skb->data - skb_mac_header(skb)); 702 else 703 skb_pull(skb, skb_mac_header(skb) - skb->data); 704 705 /* Ensure packet fits inside a single netlink attribute */ 706 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 707 if (net_dm_trunc_len) 708 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 709 710 msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL); 711 if (!msg) 712 goto out; 713 714 rc = net_dm_packet_report_fill(msg, skb, payload_len); 715 if (rc) { 716 nlmsg_free(msg); 717 goto out; 718 } 719 720 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 721 722 out: 723 consume_skb(skb); 724 } 725 726 static void net_dm_packet_work(struct work_struct *work) 727 { 728 struct per_cpu_dm_data *data; 729 struct sk_buff_head list; 730 struct sk_buff *skb; 731 unsigned long flags; 732 733 data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 734 735 __skb_queue_head_init(&list); 736 737 spin_lock_irqsave(&data->drop_queue.lock, flags); 738 skb_queue_splice_tail_init(&data->drop_queue, &list); 739 spin_unlock_irqrestore(&data->drop_queue.lock, flags); 740 741 while ((skb = __skb_dequeue(&list))) 742 net_dm_packet_report(skb); 743 } 744 745 static size_t 746 net_dm_flow_action_cookie_size(const struct devlink_trap_metadata *hw_metadata) 747 { 748 return hw_metadata->fa_cookie ? 749 nla_total_size(hw_metadata->fa_cookie->cookie_len) : 0; 750 } 751 752 static size_t 753 net_dm_hw_packet_report_size(size_t payload_len, 754 const struct devlink_trap_metadata *hw_metadata) 755 { 756 size_t size; 757 758 size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize); 759 760 return NLMSG_ALIGN(size) + 761 /* NET_DM_ATTR_ORIGIN */ 762 nla_total_size(sizeof(u16)) + 763 /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */ 764 nla_total_size(strlen(hw_metadata->trap_group_name) + 1) + 765 /* NET_DM_ATTR_HW_TRAP_NAME */ 766 nla_total_size(strlen(hw_metadata->trap_name) + 1) + 767 /* NET_DM_ATTR_IN_PORT */ 768 net_dm_in_port_size() + 769 /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ 770 net_dm_flow_action_cookie_size(hw_metadata) + 771 /* NET_DM_ATTR_TIMESTAMP */ 772 nla_total_size(sizeof(u64)) + 773 /* NET_DM_ATTR_ORIG_LEN */ 774 nla_total_size(sizeof(u32)) + 775 /* NET_DM_ATTR_PROTO */ 776 nla_total_size(sizeof(u16)) + 777 /* NET_DM_ATTR_PAYLOAD */ 778 nla_total_size(payload_len); 779 } 780 781 static int net_dm_hw_packet_report_fill(struct sk_buff *msg, 782 struct sk_buff *skb, size_t payload_len) 783 { 784 struct devlink_trap_metadata *hw_metadata; 785 struct nlattr *attr; 786 void *hdr; 787 788 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 789 790 hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0, 791 NET_DM_CMD_PACKET_ALERT); 792 if (!hdr) 793 return -EMSGSIZE; 794 795 if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW)) 796 goto nla_put_failure; 797 798 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME, 799 hw_metadata->trap_group_name)) 800 goto nla_put_failure; 801 802 if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, 803 hw_metadata->trap_name)) 804 goto nla_put_failure; 805 806 if (hw_metadata->input_dev) { 807 struct net_device *dev = hw_metadata->input_dev; 808 int rc; 809 810 rc = net_dm_packet_report_in_port_put(msg, dev->ifindex, 811 dev->name); 812 if (rc) 813 goto nla_put_failure; 814 } 815 816 if (hw_metadata->fa_cookie && 817 nla_put(msg, NET_DM_ATTR_FLOW_ACTION_COOKIE, 818 hw_metadata->fa_cookie->cookie_len, 819 hw_metadata->fa_cookie->cookie)) 820 goto nla_put_failure; 821 822 if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP, 823 ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD)) 824 goto nla_put_failure; 825 826 if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len)) 827 goto nla_put_failure; 828 829 if (!payload_len) 830 goto out; 831 832 if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol))) 833 goto nla_put_failure; 834 835 attr = skb_put(msg, nla_total_size(payload_len)); 836 attr->nla_type = NET_DM_ATTR_PAYLOAD; 837 attr->nla_len = nla_attr_size(payload_len); 838 if (skb_copy_bits(skb, 0, nla_data(attr), payload_len)) 839 goto nla_put_failure; 840 841 out: 842 genlmsg_end(msg, hdr); 843 844 return 0; 845 846 nla_put_failure: 847 genlmsg_cancel(msg, hdr); 848 return -EMSGSIZE; 849 } 850 851 static struct devlink_trap_metadata * 852 net_dm_hw_metadata_copy(const struct devlink_trap_metadata *metadata) 853 { 854 const struct flow_action_cookie *fa_cookie; 855 struct devlink_trap_metadata *hw_metadata; 856 const char *trap_group_name; 857 const char *trap_name; 858 859 hw_metadata = kzalloc(sizeof(*hw_metadata), GFP_ATOMIC); 860 if (!hw_metadata) 861 return NULL; 862 863 trap_group_name = kstrdup(metadata->trap_group_name, GFP_ATOMIC); 864 if (!trap_group_name) 865 goto free_hw_metadata; 866 hw_metadata->trap_group_name = trap_group_name; 867 868 trap_name = kstrdup(metadata->trap_name, GFP_ATOMIC); 869 if (!trap_name) 870 goto free_trap_group; 871 hw_metadata->trap_name = trap_name; 872 873 if (metadata->fa_cookie) { 874 size_t cookie_size = sizeof(*fa_cookie) + 875 metadata->fa_cookie->cookie_len; 876 877 fa_cookie = kmemdup(metadata->fa_cookie, cookie_size, 878 GFP_ATOMIC); 879 if (!fa_cookie) 880 goto free_trap_name; 881 hw_metadata->fa_cookie = fa_cookie; 882 } 883 884 hw_metadata->input_dev = metadata->input_dev; 885 netdev_hold(hw_metadata->input_dev, &hw_metadata->dev_tracker, 886 GFP_ATOMIC); 887 888 return hw_metadata; 889 890 free_trap_name: 891 kfree(trap_name); 892 free_trap_group: 893 kfree(trap_group_name); 894 free_hw_metadata: 895 kfree(hw_metadata); 896 return NULL; 897 } 898 899 static void 900 net_dm_hw_metadata_free(struct devlink_trap_metadata *hw_metadata) 901 { 902 netdev_put(hw_metadata->input_dev, &hw_metadata->dev_tracker); 903 kfree(hw_metadata->fa_cookie); 904 kfree(hw_metadata->trap_name); 905 kfree(hw_metadata->trap_group_name); 906 kfree(hw_metadata); 907 } 908 909 static void net_dm_hw_packet_report(struct sk_buff *skb) 910 { 911 struct devlink_trap_metadata *hw_metadata; 912 struct sk_buff *msg; 913 size_t payload_len; 914 int rc; 915 916 if (skb->data > skb_mac_header(skb)) 917 skb_push(skb, skb->data - skb_mac_header(skb)); 918 else 919 skb_pull(skb, skb_mac_header(skb) - skb->data); 920 921 payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE); 922 if (net_dm_trunc_len) 923 payload_len = min_t(size_t, net_dm_trunc_len, payload_len); 924 925 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 926 msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata), 927 GFP_KERNEL); 928 if (!msg) 929 goto out; 930 931 rc = net_dm_hw_packet_report_fill(msg, skb, payload_len); 932 if (rc) { 933 nlmsg_free(msg); 934 goto out; 935 } 936 937 genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL); 938 939 out: 940 net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata); 941 consume_skb(skb); 942 } 943 944 static void net_dm_hw_packet_work(struct work_struct *work) 945 { 946 struct per_cpu_dm_data *hw_data; 947 struct sk_buff_head list; 948 struct sk_buff *skb; 949 unsigned long flags; 950 951 hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work); 952 953 __skb_queue_head_init(&list); 954 955 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 956 skb_queue_splice_tail_init(&hw_data->drop_queue, &list); 957 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 958 959 while ((skb = __skb_dequeue(&list))) 960 net_dm_hw_packet_report(skb); 961 } 962 963 static void 964 net_dm_hw_trap_packet_probe(void *ignore, const struct devlink *devlink, 965 struct sk_buff *skb, 966 const struct devlink_trap_metadata *metadata) 967 { 968 struct devlink_trap_metadata *n_hw_metadata; 969 ktime_t tstamp = ktime_get_real(); 970 struct per_cpu_dm_data *hw_data; 971 struct sk_buff *nskb; 972 unsigned long flags; 973 974 if (metadata->trap_type == DEVLINK_TRAP_TYPE_CONTROL) 975 return; 976 977 if (!skb_mac_header_was_set(skb)) 978 return; 979 980 nskb = skb_clone(skb, GFP_ATOMIC); 981 if (!nskb) 982 return; 983 984 n_hw_metadata = net_dm_hw_metadata_copy(metadata); 985 if (!n_hw_metadata) 986 goto free; 987 988 NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata; 989 nskb->tstamp = tstamp; 990 991 hw_data = this_cpu_ptr(&dm_hw_cpu_data); 992 993 spin_lock_irqsave(&hw_data->drop_queue.lock, flags); 994 if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len) 995 __skb_queue_tail(&hw_data->drop_queue, nskb); 996 else 997 goto unlock_free; 998 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 999 1000 schedule_work(&hw_data->dm_alert_work); 1001 1002 return; 1003 1004 unlock_free: 1005 spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags); 1006 u64_stats_update_begin(&hw_data->stats.syncp); 1007 u64_stats_inc(&hw_data->stats.dropped); 1008 u64_stats_update_end(&hw_data->stats.syncp); 1009 net_dm_hw_metadata_free(n_hw_metadata); 1010 free: 1011 consume_skb(nskb); 1012 } 1013 1014 static const struct net_dm_alert_ops net_dm_alert_packet_ops = { 1015 .kfree_skb_probe = net_dm_packet_trace_kfree_skb_hit, 1016 .napi_poll_probe = net_dm_packet_trace_napi_poll_hit, 1017 .work_item_func = net_dm_packet_work, 1018 .hw_work_item_func = net_dm_hw_packet_work, 1019 .hw_trap_probe = net_dm_hw_trap_packet_probe, 1020 }; 1021 1022 static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = { 1023 [NET_DM_ALERT_MODE_SUMMARY] = &net_dm_alert_summary_ops, 1024 [NET_DM_ALERT_MODE_PACKET] = &net_dm_alert_packet_ops, 1025 }; 1026 1027 #if IS_ENABLED(CONFIG_NET_DEVLINK) 1028 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1029 { 1030 return register_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1031 } 1032 1033 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1034 { 1035 unregister_trace_devlink_trap_report(ops->hw_trap_probe, NULL); 1036 tracepoint_synchronize_unregister(); 1037 } 1038 #else 1039 static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops) 1040 { 1041 return -EOPNOTSUPP; 1042 } 1043 1044 static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops) 1045 { 1046 } 1047 #endif 1048 1049 static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack) 1050 { 1051 const struct net_dm_alert_ops *ops; 1052 int cpu, rc; 1053 1054 if (monitor_hw) { 1055 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled"); 1056 return -EAGAIN; 1057 } 1058 1059 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1060 1061 if (!try_module_get(THIS_MODULE)) { 1062 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1063 return -ENODEV; 1064 } 1065 1066 for_each_possible_cpu(cpu) { 1067 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1068 struct net_dm_hw_entries *hw_entries; 1069 1070 INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func); 1071 timer_setup(&hw_data->send_timer, sched_send_work, 0); 1072 hw_entries = net_dm_hw_reset_per_cpu_data(hw_data); 1073 kfree(hw_entries); 1074 } 1075 1076 rc = net_dm_hw_probe_register(ops); 1077 if (rc) { 1078 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to devlink_trap_probe() tracepoint"); 1079 goto err_module_put; 1080 } 1081 1082 monitor_hw = true; 1083 1084 return 0; 1085 1086 err_module_put: 1087 for_each_possible_cpu(cpu) { 1088 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1089 struct sk_buff *skb; 1090 1091 del_timer_sync(&hw_data->send_timer); 1092 cancel_work_sync(&hw_data->dm_alert_work); 1093 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1094 struct devlink_trap_metadata *hw_metadata; 1095 1096 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1097 net_dm_hw_metadata_free(hw_metadata); 1098 consume_skb(skb); 1099 } 1100 } 1101 module_put(THIS_MODULE); 1102 return rc; 1103 } 1104 1105 static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack) 1106 { 1107 const struct net_dm_alert_ops *ops; 1108 int cpu; 1109 1110 if (!monitor_hw) { 1111 NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled"); 1112 return; 1113 } 1114 1115 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1116 1117 monitor_hw = false; 1118 1119 net_dm_hw_probe_unregister(ops); 1120 1121 for_each_possible_cpu(cpu) { 1122 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1123 struct sk_buff *skb; 1124 1125 del_timer_sync(&hw_data->send_timer); 1126 cancel_work_sync(&hw_data->dm_alert_work); 1127 while ((skb = __skb_dequeue(&hw_data->drop_queue))) { 1128 struct devlink_trap_metadata *hw_metadata; 1129 1130 hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata; 1131 net_dm_hw_metadata_free(hw_metadata); 1132 consume_skb(skb); 1133 } 1134 } 1135 1136 module_put(THIS_MODULE); 1137 } 1138 1139 static int net_dm_trace_on_set(struct netlink_ext_ack *extack) 1140 { 1141 const struct net_dm_alert_ops *ops; 1142 int cpu, rc; 1143 1144 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1145 1146 if (!try_module_get(THIS_MODULE)) { 1147 NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module"); 1148 return -ENODEV; 1149 } 1150 1151 for_each_possible_cpu(cpu) { 1152 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1153 struct sk_buff *skb; 1154 1155 INIT_WORK(&data->dm_alert_work, ops->work_item_func); 1156 timer_setup(&data->send_timer, sched_send_work, 0); 1157 /* Allocate a new per-CPU skb for the summary alert message and 1158 * free the old one which might contain stale data from 1159 * previous tracing. 1160 */ 1161 skb = reset_per_cpu_data(data); 1162 consume_skb(skb); 1163 } 1164 1165 rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1166 if (rc) { 1167 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint"); 1168 goto err_module_put; 1169 } 1170 1171 rc = register_trace_napi_poll(ops->napi_poll_probe, NULL); 1172 if (rc) { 1173 NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint"); 1174 goto err_unregister_trace; 1175 } 1176 1177 return 0; 1178 1179 err_unregister_trace: 1180 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1181 err_module_put: 1182 for_each_possible_cpu(cpu) { 1183 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1184 struct sk_buff *skb; 1185 1186 del_timer_sync(&data->send_timer); 1187 cancel_work_sync(&data->dm_alert_work); 1188 while ((skb = __skb_dequeue(&data->drop_queue))) 1189 consume_skb(skb); 1190 } 1191 module_put(THIS_MODULE); 1192 return rc; 1193 } 1194 1195 static void net_dm_trace_off_set(void) 1196 { 1197 const struct net_dm_alert_ops *ops; 1198 int cpu; 1199 1200 ops = net_dm_alert_ops_arr[net_dm_alert_mode]; 1201 1202 unregister_trace_napi_poll(ops->napi_poll_probe, NULL); 1203 unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); 1204 1205 tracepoint_synchronize_unregister(); 1206 1207 /* Make sure we do not send notifications to user space after request 1208 * to stop tracing returns. 1209 */ 1210 for_each_possible_cpu(cpu) { 1211 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1212 struct sk_buff *skb; 1213 1214 del_timer_sync(&data->send_timer); 1215 cancel_work_sync(&data->dm_alert_work); 1216 while ((skb = __skb_dequeue(&data->drop_queue))) 1217 consume_skb(skb); 1218 } 1219 1220 module_put(THIS_MODULE); 1221 } 1222 1223 static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack) 1224 { 1225 int rc = 0; 1226 1227 if (state == trace_state) { 1228 NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state"); 1229 return -EAGAIN; 1230 } 1231 1232 switch (state) { 1233 case TRACE_ON: 1234 rc = net_dm_trace_on_set(extack); 1235 break; 1236 case TRACE_OFF: 1237 net_dm_trace_off_set(); 1238 break; 1239 default: 1240 rc = 1; 1241 break; 1242 } 1243 1244 if (!rc) 1245 trace_state = state; 1246 else 1247 rc = -EINPROGRESS; 1248 1249 return rc; 1250 } 1251 1252 static bool net_dm_is_monitoring(void) 1253 { 1254 return trace_state == TRACE_ON || monitor_hw; 1255 } 1256 1257 static int net_dm_alert_mode_get_from_info(struct genl_info *info, 1258 enum net_dm_alert_mode *p_alert_mode) 1259 { 1260 u8 val; 1261 1262 val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]); 1263 1264 switch (val) { 1265 case NET_DM_ALERT_MODE_SUMMARY: 1266 case NET_DM_ALERT_MODE_PACKET: 1267 *p_alert_mode = val; 1268 break; 1269 default: 1270 return -EINVAL; 1271 } 1272 1273 return 0; 1274 } 1275 1276 static int net_dm_alert_mode_set(struct genl_info *info) 1277 { 1278 struct netlink_ext_ack *extack = info->extack; 1279 enum net_dm_alert_mode alert_mode; 1280 int rc; 1281 1282 if (!info->attrs[NET_DM_ATTR_ALERT_MODE]) 1283 return 0; 1284 1285 rc = net_dm_alert_mode_get_from_info(info, &alert_mode); 1286 if (rc) { 1287 NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode"); 1288 return -EINVAL; 1289 } 1290 1291 net_dm_alert_mode = alert_mode; 1292 1293 return 0; 1294 } 1295 1296 static void net_dm_trunc_len_set(struct genl_info *info) 1297 { 1298 if (!info->attrs[NET_DM_ATTR_TRUNC_LEN]) 1299 return; 1300 1301 net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]); 1302 } 1303 1304 static void net_dm_queue_len_set(struct genl_info *info) 1305 { 1306 if (!info->attrs[NET_DM_ATTR_QUEUE_LEN]) 1307 return; 1308 1309 net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]); 1310 } 1311 1312 static int net_dm_cmd_config(struct sk_buff *skb, 1313 struct genl_info *info) 1314 { 1315 struct netlink_ext_ack *extack = info->extack; 1316 int rc; 1317 1318 if (net_dm_is_monitoring()) { 1319 NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring"); 1320 return -EBUSY; 1321 } 1322 1323 rc = net_dm_alert_mode_set(info); 1324 if (rc) 1325 return rc; 1326 1327 net_dm_trunc_len_set(info); 1328 1329 net_dm_queue_len_set(info); 1330 1331 return 0; 1332 } 1333 1334 static int net_dm_monitor_start(bool set_sw, bool set_hw, 1335 struct netlink_ext_ack *extack) 1336 { 1337 bool sw_set = false; 1338 int rc; 1339 1340 if (set_sw) { 1341 rc = set_all_monitor_traces(TRACE_ON, extack); 1342 if (rc) 1343 return rc; 1344 sw_set = true; 1345 } 1346 1347 if (set_hw) { 1348 rc = net_dm_hw_monitor_start(extack); 1349 if (rc) 1350 goto err_monitor_hw; 1351 } 1352 1353 return 0; 1354 1355 err_monitor_hw: 1356 if (sw_set) 1357 set_all_monitor_traces(TRACE_OFF, extack); 1358 return rc; 1359 } 1360 1361 static void net_dm_monitor_stop(bool set_sw, bool set_hw, 1362 struct netlink_ext_ack *extack) 1363 { 1364 if (set_hw) 1365 net_dm_hw_monitor_stop(extack); 1366 if (set_sw) 1367 set_all_monitor_traces(TRACE_OFF, extack); 1368 } 1369 1370 static int net_dm_cmd_trace(struct sk_buff *skb, 1371 struct genl_info *info) 1372 { 1373 bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS]; 1374 bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS]; 1375 struct netlink_ext_ack *extack = info->extack; 1376 1377 /* To maintain backward compatibility, we start / stop monitoring of 1378 * software drops if no flag is specified. 1379 */ 1380 if (!set_sw && !set_hw) 1381 set_sw = true; 1382 1383 switch (info->genlhdr->cmd) { 1384 case NET_DM_CMD_START: 1385 return net_dm_monitor_start(set_sw, set_hw, extack); 1386 case NET_DM_CMD_STOP: 1387 net_dm_monitor_stop(set_sw, set_hw, extack); 1388 return 0; 1389 } 1390 1391 return -EOPNOTSUPP; 1392 } 1393 1394 static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info) 1395 { 1396 void *hdr; 1397 1398 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1399 &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW); 1400 if (!hdr) 1401 return -EMSGSIZE; 1402 1403 if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode)) 1404 goto nla_put_failure; 1405 1406 if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len)) 1407 goto nla_put_failure; 1408 1409 if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len)) 1410 goto nla_put_failure; 1411 1412 genlmsg_end(msg, hdr); 1413 1414 return 0; 1415 1416 nla_put_failure: 1417 genlmsg_cancel(msg, hdr); 1418 return -EMSGSIZE; 1419 } 1420 1421 static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info) 1422 { 1423 struct sk_buff *msg; 1424 int rc; 1425 1426 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1427 if (!msg) 1428 return -ENOMEM; 1429 1430 rc = net_dm_config_fill(msg, info); 1431 if (rc) 1432 goto free_msg; 1433 1434 return genlmsg_reply(msg, info); 1435 1436 free_msg: 1437 nlmsg_free(msg); 1438 return rc; 1439 } 1440 1441 static void net_dm_stats_read(struct net_dm_stats *stats) 1442 { 1443 int cpu; 1444 1445 memset(stats, 0, sizeof(*stats)); 1446 for_each_possible_cpu(cpu) { 1447 struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); 1448 struct net_dm_stats *cpu_stats = &data->stats; 1449 unsigned int start; 1450 u64 dropped; 1451 1452 do { 1453 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1454 dropped = u64_stats_read(&cpu_stats->dropped); 1455 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1456 1457 u64_stats_add(&stats->dropped, dropped); 1458 } 1459 } 1460 1461 static int net_dm_stats_put(struct sk_buff *msg) 1462 { 1463 struct net_dm_stats stats; 1464 struct nlattr *attr; 1465 1466 net_dm_stats_read(&stats); 1467 1468 attr = nla_nest_start(msg, NET_DM_ATTR_STATS); 1469 if (!attr) 1470 return -EMSGSIZE; 1471 1472 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1473 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1474 goto nla_put_failure; 1475 1476 nla_nest_end(msg, attr); 1477 1478 return 0; 1479 1480 nla_put_failure: 1481 nla_nest_cancel(msg, attr); 1482 return -EMSGSIZE; 1483 } 1484 1485 static void net_dm_hw_stats_read(struct net_dm_stats *stats) 1486 { 1487 int cpu; 1488 1489 memset(stats, 0, sizeof(*stats)); 1490 for_each_possible_cpu(cpu) { 1491 struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1492 struct net_dm_stats *cpu_stats = &hw_data->stats; 1493 unsigned int start; 1494 u64 dropped; 1495 1496 do { 1497 start = u64_stats_fetch_begin(&cpu_stats->syncp); 1498 dropped = u64_stats_read(&cpu_stats->dropped); 1499 } while (u64_stats_fetch_retry(&cpu_stats->syncp, start)); 1500 1501 u64_stats_add(&stats->dropped, dropped); 1502 } 1503 } 1504 1505 static int net_dm_hw_stats_put(struct sk_buff *msg) 1506 { 1507 struct net_dm_stats stats; 1508 struct nlattr *attr; 1509 1510 net_dm_hw_stats_read(&stats); 1511 1512 attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS); 1513 if (!attr) 1514 return -EMSGSIZE; 1515 1516 if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED, 1517 u64_stats_read(&stats.dropped), NET_DM_ATTR_PAD)) 1518 goto nla_put_failure; 1519 1520 nla_nest_end(msg, attr); 1521 1522 return 0; 1523 1524 nla_put_failure: 1525 nla_nest_cancel(msg, attr); 1526 return -EMSGSIZE; 1527 } 1528 1529 static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info) 1530 { 1531 void *hdr; 1532 int rc; 1533 1534 hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, 1535 &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW); 1536 if (!hdr) 1537 return -EMSGSIZE; 1538 1539 rc = net_dm_stats_put(msg); 1540 if (rc) 1541 goto nla_put_failure; 1542 1543 rc = net_dm_hw_stats_put(msg); 1544 if (rc) 1545 goto nla_put_failure; 1546 1547 genlmsg_end(msg, hdr); 1548 1549 return 0; 1550 1551 nla_put_failure: 1552 genlmsg_cancel(msg, hdr); 1553 return -EMSGSIZE; 1554 } 1555 1556 static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info) 1557 { 1558 struct sk_buff *msg; 1559 int rc; 1560 1561 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1562 if (!msg) 1563 return -ENOMEM; 1564 1565 rc = net_dm_stats_fill(msg, info); 1566 if (rc) 1567 goto free_msg; 1568 1569 return genlmsg_reply(msg, info); 1570 1571 free_msg: 1572 nlmsg_free(msg); 1573 return rc; 1574 } 1575 1576 static int dropmon_net_event(struct notifier_block *ev_block, 1577 unsigned long event, void *ptr) 1578 { 1579 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1580 struct dm_hw_stat_delta *stat; 1581 1582 switch (event) { 1583 case NETDEV_REGISTER: 1584 if (WARN_ON_ONCE(rtnl_dereference(dev->dm_private))) 1585 break; 1586 stat = kzalloc(sizeof(*stat), GFP_KERNEL); 1587 if (!stat) 1588 break; 1589 1590 stat->last_rx = jiffies; 1591 rcu_assign_pointer(dev->dm_private, stat); 1592 1593 break; 1594 case NETDEV_UNREGISTER: 1595 stat = rtnl_dereference(dev->dm_private); 1596 if (stat) { 1597 rcu_assign_pointer(dev->dm_private, NULL); 1598 kfree_rcu(stat, rcu); 1599 } 1600 break; 1601 } 1602 return NOTIFY_DONE; 1603 } 1604 1605 static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = { 1606 [NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 }, 1607 [NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 }, 1608 [NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 }, 1609 [NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 }, 1610 [NET_DM_ATTR_SW_DROPS] = {. type = NLA_FLAG }, 1611 [NET_DM_ATTR_HW_DROPS] = {. type = NLA_FLAG }, 1612 }; 1613 1614 static const struct genl_small_ops dropmon_ops[] = { 1615 { 1616 .cmd = NET_DM_CMD_CONFIG, 1617 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1618 .doit = net_dm_cmd_config, 1619 .flags = GENL_ADMIN_PERM, 1620 }, 1621 { 1622 .cmd = NET_DM_CMD_START, 1623 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1624 .doit = net_dm_cmd_trace, 1625 .flags = GENL_ADMIN_PERM, 1626 }, 1627 { 1628 .cmd = NET_DM_CMD_STOP, 1629 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1630 .doit = net_dm_cmd_trace, 1631 .flags = GENL_ADMIN_PERM, 1632 }, 1633 { 1634 .cmd = NET_DM_CMD_CONFIG_GET, 1635 .doit = net_dm_cmd_config_get, 1636 }, 1637 { 1638 .cmd = NET_DM_CMD_STATS_GET, 1639 .doit = net_dm_cmd_stats_get, 1640 }, 1641 }; 1642 1643 static int net_dm_nl_pre_doit(const struct genl_split_ops *ops, 1644 struct sk_buff *skb, struct genl_info *info) 1645 { 1646 mutex_lock(&net_dm_mutex); 1647 1648 return 0; 1649 } 1650 1651 static void net_dm_nl_post_doit(const struct genl_split_ops *ops, 1652 struct sk_buff *skb, struct genl_info *info) 1653 { 1654 mutex_unlock(&net_dm_mutex); 1655 } 1656 1657 static struct genl_family net_drop_monitor_family __ro_after_init = { 1658 .hdrsize = 0, 1659 .name = "NET_DM", 1660 .version = 2, 1661 .maxattr = NET_DM_ATTR_MAX, 1662 .policy = net_dm_nl_policy, 1663 .pre_doit = net_dm_nl_pre_doit, 1664 .post_doit = net_dm_nl_post_doit, 1665 .module = THIS_MODULE, 1666 .small_ops = dropmon_ops, 1667 .n_small_ops = ARRAY_SIZE(dropmon_ops), 1668 .resv_start_op = NET_DM_CMD_STATS_GET + 1, 1669 .mcgrps = dropmon_mcgrps, 1670 .n_mcgrps = ARRAY_SIZE(dropmon_mcgrps), 1671 }; 1672 1673 static struct notifier_block dropmon_net_notifier = { 1674 .notifier_call = dropmon_net_event 1675 }; 1676 1677 static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data) 1678 { 1679 raw_spin_lock_init(&data->lock); 1680 skb_queue_head_init(&data->drop_queue); 1681 u64_stats_init(&data->stats.syncp); 1682 } 1683 1684 static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data) 1685 { 1686 WARN_ON(!skb_queue_empty(&data->drop_queue)); 1687 } 1688 1689 static void net_dm_cpu_data_init(int cpu) 1690 { 1691 struct per_cpu_dm_data *data; 1692 1693 data = &per_cpu(dm_cpu_data, cpu); 1694 __net_dm_cpu_data_init(data); 1695 } 1696 1697 static void net_dm_cpu_data_fini(int cpu) 1698 { 1699 struct per_cpu_dm_data *data; 1700 1701 data = &per_cpu(dm_cpu_data, cpu); 1702 /* At this point, we should have exclusive access 1703 * to this struct and can free the skb inside it. 1704 */ 1705 consume_skb(data->skb); 1706 __net_dm_cpu_data_fini(data); 1707 } 1708 1709 static void net_dm_hw_cpu_data_init(int cpu) 1710 { 1711 struct per_cpu_dm_data *hw_data; 1712 1713 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1714 __net_dm_cpu_data_init(hw_data); 1715 } 1716 1717 static void net_dm_hw_cpu_data_fini(int cpu) 1718 { 1719 struct per_cpu_dm_data *hw_data; 1720 1721 hw_data = &per_cpu(dm_hw_cpu_data, cpu); 1722 kfree(hw_data->hw_entries); 1723 __net_dm_cpu_data_fini(hw_data); 1724 } 1725 1726 static int __init init_net_drop_monitor(void) 1727 { 1728 int cpu, rc; 1729 1730 pr_info("Initializing network drop monitor service\n"); 1731 1732 if (sizeof(void *) > 8) { 1733 pr_err("Unable to store program counters on this arch, Drop monitor failed\n"); 1734 return -ENOSPC; 1735 } 1736 1737 rc = genl_register_family(&net_drop_monitor_family); 1738 if (rc) { 1739 pr_err("Could not create drop monitor netlink family\n"); 1740 return rc; 1741 } 1742 WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT); 1743 1744 rc = register_netdevice_notifier(&dropmon_net_notifier); 1745 if (rc < 0) { 1746 pr_crit("Failed to register netdevice notifier\n"); 1747 goto out_unreg; 1748 } 1749 1750 rc = 0; 1751 1752 for_each_possible_cpu(cpu) { 1753 net_dm_cpu_data_init(cpu); 1754 net_dm_hw_cpu_data_init(cpu); 1755 } 1756 1757 goto out; 1758 1759 out_unreg: 1760 genl_unregister_family(&net_drop_monitor_family); 1761 out: 1762 return rc; 1763 } 1764 1765 static void exit_net_drop_monitor(void) 1766 { 1767 int cpu; 1768 1769 BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier)); 1770 1771 /* 1772 * Because of the module_get/put we do in the trace state change path 1773 * we are guaranteed not to have any current users when we get here 1774 */ 1775 1776 for_each_possible_cpu(cpu) { 1777 net_dm_hw_cpu_data_fini(cpu); 1778 net_dm_cpu_data_fini(cpu); 1779 } 1780 1781 BUG_ON(genl_unregister_family(&net_drop_monitor_family)); 1782 } 1783 1784 module_init(init_net_drop_monitor); 1785 module_exit(exit_net_drop_monitor); 1786 1787 MODULE_LICENSE("GPL v2"); 1788 MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>"); 1789 MODULE_ALIAS_GENL_FAMILY("NET_DM"); 1790 MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts"); 1791