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 <linux/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 */
  50static int trace_state = TRACE_OFF;
  51static bool monitor_hw;
  52
  53/* net_dm_mutex
  54 *
  55 * An overall lock guarding every operation coming from userspace.
  56 */
  57static DEFINE_MUTEX(net_dm_mutex);
  58
  59struct 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
  66struct net_dm_hw_entry {
  67	char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
  68	u32 count;
  69};
  70
  71struct net_dm_hw_entries {
  72	u32 num_entries;
  73	struct net_dm_hw_entry entries[];
  74};
  75
  76struct 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
  90struct dm_hw_stat_delta {
 
  91	unsigned long last_rx;
  92	unsigned long last_drop_val;
  93	struct rcu_head rcu;
 
  94};
  95
  96static struct genl_family net_drop_monitor_family;
 
 
 
 
 
  97
  98static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
  99static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 100
 101static int dm_hit_limit = 64;
 102static int dm_delay = 1;
 103static unsigned long dm_hw_check_delta = 2*HZ;
 104
 105static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
 106static u32 net_dm_trunc_len;
 107static u32 net_dm_queue_len = 1000;
 108
 109struct 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
 123struct 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
 133static 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
 169err:
 170	mod_timer(&data->send_timer, jiffies + HZ / 10);
 171out:
 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
 186static const struct genl_multicast_group dropmon_mcgrps[] = {
 187	{ .name = "events", .flags = GENL_MCAST_CAP_SYS_ADMIN, },
 188};
 189
 190static 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 */
 209static 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
 216static 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
 262out:
 263	raw_spin_unlock_irqrestore(&data->lock, flags);
 264}
 265
 266static 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
 274static 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
 303static struct net_dm_hw_entries *
 304net_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
 326static 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
 345nla_put_failure:
 346	nla_nest_cancel(msg, attr);
 347	return -EMSGSIZE;
 348}
 349
 350static 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
 372nla_put_failure:
 373	nla_nest_cancel(msg, attr);
 374	return -EMSGSIZE;
 375}
 376
 377static int
 378net_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
 404nla_put_failure:
 405	genlmsg_cancel(msg, hdr);
 406	return -EMSGSIZE;
 407}
 408
 409static 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
 434out:
 435	kfree(hw_entries);
 436}
 437
 438static void
 439net_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
 481out:
 482	raw_spin_unlock_irqrestore(&hw_data->lock, flags);
 483}
 484
 485static 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
 493static 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
 533unlock_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
 541static void net_dm_packet_trace_napi_poll_hit(void *ignore,
 542					      struct napi_struct *napi,
 543					      int work, int budget)
 544{
 545}
 546
 547static 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
 560static 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
 587static 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
 607nla_put_failure:
 608	nla_nest_cancel(msg, attr);
 609	return -EMSGSIZE;
 610}
 611
 612static 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
 681out:
 682	genlmsg_end(msg, hdr);
 683
 684	return 0;
 685
 686nla_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
 693static 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
 722out:
 723	consume_skb(skb);
 724}
 725
 726static 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
 745static size_t
 746net_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
 752static size_t
 753net_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
 781static 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
 841out:
 842	genlmsg_end(msg, hdr);
 843
 844	return 0;
 845
 846nla_put_failure:
 847	genlmsg_cancel(msg, hdr);
 848	return -EMSGSIZE;
 849}
 850
 851static struct devlink_trap_metadata *
 852net_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
 890free_trap_name:
 891	kfree(trap_name);
 892free_trap_group:
 893	kfree(trap_group_name);
 894free_hw_metadata:
 895	kfree(hw_metadata);
 896	return NULL;
 897}
 898
 899static void
 900net_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
 909static 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
 939out:
 940	net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
 941	consume_skb(skb);
 942}
 943
 944static 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
 963static void
 964net_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
1004unlock_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);
1010free:
1011	consume_skb(nskb);
1012}
1013
1014static 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
1022static 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)
1028static 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
1033static 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
1039static int net_dm_hw_probe_register(const struct net_dm_alert_ops *ops)
1040{
1041	return -EOPNOTSUPP;
1042}
1043
1044static void net_dm_hw_probe_unregister(const struct net_dm_alert_ops *ops)
1045{
1046}
1047#endif
1048
1049static 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
1086err_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
1105static 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
1139static 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
1179err_unregister_trace:
1180	unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
1181err_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
1195static 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
1223static 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
1252static bool net_dm_is_monitoring(void)
1253{
1254	return trace_state == TRACE_ON || monitor_hw;
1255}
1256
1257static 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
1276static 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
1296static 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
1304static 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
1312static 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
1334static 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
1355err_monitor_hw:
1356	if (sw_set)
1357		set_all_monitor_traces(TRACE_OFF, extack);
1358	return rc;
1359}
1360
1361static 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
1370static 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
1394static 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
1416nla_put_failure:
1417	genlmsg_cancel(msg, hdr);
1418	return -EMSGSIZE;
1419}
1420
1421static 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
1436free_msg:
1437	nlmsg_free(msg);
1438	return rc;
1439}
1440
1441static 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
1461static 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
1480nla_put_failure:
1481	nla_nest_cancel(msg, attr);
1482	return -EMSGSIZE;
1483}
1484
1485static 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
1505static 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
1524nla_put_failure:
1525	nla_nest_cancel(msg, attr);
1526	return -EMSGSIZE;
1527}
1528
1529static 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
1551nla_put_failure:
1552	genlmsg_cancel(msg, hdr);
1553	return -EMSGSIZE;
1554}
1555
1556static 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
1571free_msg:
1572	nlmsg_free(msg);
1573	return rc;
1574}
1575
1576static 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
1605static 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
1614static 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
1643static 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
1651static 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
1657static 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
1673static struct notifier_block dropmon_net_notifier = {
1674	.notifier_call = dropmon_net_event
1675};
1676
1677static 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
1684static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
1685{
1686	WARN_ON(!skb_queue_empty(&data->drop_queue));
1687}
1688
1689static 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
1697static 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
1709static 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
1717static 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
1726static 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	for_each_possible_cpu(cpu) {
1738		net_dm_cpu_data_init(cpu);
1739		net_dm_hw_cpu_data_init(cpu);
 
 
1740	}
 
1741
1742	rc = register_netdevice_notifier(&dropmon_net_notifier);
1743	if (rc < 0) {
1744		pr_crit("Failed to register netdevice notifier\n");
1745		return rc;
1746	}
1747
1748	rc = genl_register_family(&net_drop_monitor_family);
1749	if (rc) {
1750		pr_err("Could not create drop monitor netlink family\n");
1751		goto out_unreg;
1752	}
1753	WARN_ON(net_drop_monitor_family.mcgrp_offset != NET_DM_GRP_ALERT);
1754
1755	rc = 0;
1756
 
 
 
 
 
 
 
 
 
 
 
1757	goto out;
1758
1759out_unreg:
1760	WARN_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1761out:
1762	return rc;
1763}
1764
1765static void exit_net_drop_monitor(void)
1766{
 
1767	int cpu;
1768
 
 
1769	/*
1770	 * Because of the module_get/put we do in the trace state change path
1771	 * we are guaranteed not to have any current users when we get here
 
 
1772	 */
1773	BUG_ON(genl_unregister_family(&net_drop_monitor_family));
1774
1775	BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
1776
1777	for_each_possible_cpu(cpu) {
1778		net_dm_hw_cpu_data_fini(cpu);
1779		net_dm_cpu_data_fini(cpu);
 
 
 
 
 
 
1780	}
 
 
1781}
1782
1783module_init(init_net_drop_monitor);
1784module_exit(exit_net_drop_monitor);
1785
1786MODULE_LICENSE("GPL v2");
1787MODULE_AUTHOR("Neil Horman <nhorman@tuxdriver.com>");
1788MODULE_ALIAS_GENL_FAMILY("NET_DM");
1789MODULE_DESCRIPTION("Monitoring code for network dropped packet alerts");