/net/netfilter/ipvs/ip_vs_conn.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * IPVS         An implementation of the IP virtual server support for the
   4 *              LINUX operating system.  IPVS is now implemented as a module
   5 *              over the Netfilter framework. IPVS can be used to build a
   6 *              high-performance and highly available server based on a
   7 *              cluster of servers.
   8 *
   9 * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
  10 *              Peter Kese <peter.kese@ijs.si>
  11 *              Julian Anastasov <ja@ssi.bg>
  12 *
  13 * The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
  14 * with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
  15 * and others. Many code here is taken from IP MASQ code of kernel 2.2.
  16 *
  17 * Changes:
  18 */
  19
  20#define KMSG_COMPONENT "IPVS"
  21#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  22
  23#include <linux/interrupt.h>
  24#include <linux/in.h>
  25#include <linux/inet.h>
  26#include <linux/net.h>
  27#include <linux/kernel.h>
  28#include <linux/module.h>
  29#include <linux/vmalloc.h>
  30#include <linux/proc_fs.h>		/* for proc_net_* */
  31#include <linux/slab.h>
  32#include <linux/seq_file.h>
  33#include <linux/jhash.h>
  34#include <linux/random.h>
  35
  36#include <net/net_namespace.h>
  37#include <net/ip_vs.h>
  38
  39
  40#ifndef CONFIG_IP_VS_TAB_BITS
  41#define CONFIG_IP_VS_TAB_BITS	12
  42#endif
  43
  44/*
  45 * Connection hash size. Default is what was selected at compile time.
  46*/
  47static int ip_vs_conn_tab_bits = CONFIG_IP_VS_TAB_BITS;
  48module_param_named(conn_tab_bits, ip_vs_conn_tab_bits, int, 0444);
  49MODULE_PARM_DESC(conn_tab_bits, "Set connections' hash size");
  50
  51/* size and mask values */
  52int ip_vs_conn_tab_size __read_mostly;
  53static int ip_vs_conn_tab_mask __read_mostly;
  54
  55/*
  56 *  Connection hash table: for input and output packets lookups of IPVS
  57 */
  58static struct hlist_head *ip_vs_conn_tab __read_mostly;
  59
  60/*  SLAB cache for IPVS connections */
  61static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
  62
  63/*  counter for no client port connections */
  64static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
  65
  66/* random value for IPVS connection hash */
  67static unsigned int ip_vs_conn_rnd __read_mostly;
  68
  69/*
  70 *  Fine locking granularity for big connection hash table
  71 */
  72#define CT_LOCKARRAY_BITS  5
  73#define CT_LOCKARRAY_SIZE  (1<<CT_LOCKARRAY_BITS)
  74#define CT_LOCKARRAY_MASK  (CT_LOCKARRAY_SIZE-1)
  75
  76/* We need an addrstrlen that works with or without v6 */
  77#ifdef CONFIG_IP_VS_IPV6
  78#define IP_VS_ADDRSTRLEN INET6_ADDRSTRLEN
  79#else
  80#define IP_VS_ADDRSTRLEN (8+1)
  81#endif
  82
  83struct ip_vs_aligned_lock
  84{
  85	spinlock_t	l;
  86} __attribute__((__aligned__(SMP_CACHE_BYTES)));
  87
  88/* lock array for conn table */
  89static struct ip_vs_aligned_lock
  90__ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
  91
  92static inline void ct_write_lock_bh(unsigned int key)
  93{
  94	spin_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
  95}
  96
  97static inline void ct_write_unlock_bh(unsigned int key)
  98{
  99	spin_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
 100}
 101
 102static void ip_vs_conn_expire(struct timer_list *t);
 103
 104/*
 105 *	Returns hash value for IPVS connection entry
 106 */
 107static unsigned int ip_vs_conn_hashkey(struct netns_ipvs *ipvs, int af, unsigned int proto,
 108				       const union nf_inet_addr *addr,
 109				       __be16 port)
 110{
 111#ifdef CONFIG_IP_VS_IPV6
 112	if (af == AF_INET6)
 113		return (jhash_3words(jhash(addr, 16, ip_vs_conn_rnd),
 114				    (__force u32)port, proto, ip_vs_conn_rnd) ^
 115			((size_t)ipvs>>8)) & ip_vs_conn_tab_mask;
 116#endif
 117	return (jhash_3words((__force u32)addr->ip, (__force u32)port, proto,
 118			    ip_vs_conn_rnd) ^
 119		((size_t)ipvs>>8)) & ip_vs_conn_tab_mask;
 120}
 121
 122static unsigned int ip_vs_conn_hashkey_param(const struct ip_vs_conn_param *p,
 123					     bool inverse)
 124{
 125	const union nf_inet_addr *addr;
 126	__be16 port;
 127
 128	if (p->pe_data && p->pe->hashkey_raw)
 129		return p->pe->hashkey_raw(p, ip_vs_conn_rnd, inverse) &
 130			ip_vs_conn_tab_mask;
 131
 132	if (likely(!inverse)) {
 133		addr = p->caddr;
 134		port = p->cport;
 135	} else {
 136		addr = p->vaddr;
 137		port = p->vport;
 138	}
 139
 140	return ip_vs_conn_hashkey(p->ipvs, p->af, p->protocol, addr, port);
 141}
 142
 143static unsigned int ip_vs_conn_hashkey_conn(const struct ip_vs_conn *cp)
 144{
 145	struct ip_vs_conn_param p;
 146
 147	ip_vs_conn_fill_param(cp->ipvs, cp->af, cp->protocol,
 148			      &cp->caddr, cp->cport, NULL, 0, &p);
 149
 150	if (cp->pe) {
 151		p.pe = cp->pe;
 152		p.pe_data = cp->pe_data;
 153		p.pe_data_len = cp->pe_data_len;
 154	}
 155
 156	return ip_vs_conn_hashkey_param(&p, false);
 157}
 158
 159/*
 160 *	Hashes ip_vs_conn in ip_vs_conn_tab by netns,proto,addr,port.
 161 *	returns bool success.
 162 */
 163static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
 164{
 165	unsigned int hash;
 166	int ret;
 167
 168	if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
 169		return 0;
 170
 171	/* Hash by protocol, client address and port */
 172	hash = ip_vs_conn_hashkey_conn(cp);
 173
 174	ct_write_lock_bh(hash);
 175	spin_lock(&cp->lock);
 176
 177	if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
 178		cp->flags |= IP_VS_CONN_F_HASHED;
 179		refcount_inc(&cp->refcnt);
 180		hlist_add_head_rcu(&cp->c_list, &ip_vs_conn_tab[hash]);
 181		ret = 1;
 182	} else {
 183		pr_err("%s(): request for already hashed, called from %pS\n",
 184		       __func__, __builtin_return_address(0));
 185		ret = 0;
 186	}
 187
 188	spin_unlock(&cp->lock);
 189	ct_write_unlock_bh(hash);
 190
 191	return ret;
 192}
 193
 194
 195/*
 196 *	UNhashes ip_vs_conn from ip_vs_conn_tab.
 197 *	returns bool success. Caller should hold conn reference.
 198 */
 199static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
 200{
 201	unsigned int hash;
 202	int ret;
 203
 204	/* unhash it and decrease its reference counter */
 205	hash = ip_vs_conn_hashkey_conn(cp);
 206
 207	ct_write_lock_bh(hash);
 208	spin_lock(&cp->lock);
 209
 210	if (cp->flags & IP_VS_CONN_F_HASHED) {
 211		hlist_del_rcu(&cp->c_list);
 212		cp->flags &= ~IP_VS_CONN_F_HASHED;
 213		refcount_dec(&cp->refcnt);
 214		ret = 1;
 215	} else
 216		ret = 0;
 217
 218	spin_unlock(&cp->lock);
 219	ct_write_unlock_bh(hash);
 220
 221	return ret;
 222}
 223
 224/* Try to unlink ip_vs_conn from ip_vs_conn_tab.
 225 * returns bool success.
 226 */
 227static inline bool ip_vs_conn_unlink(struct ip_vs_conn *cp)
 228{
 229	unsigned int hash;
 230	bool ret = false;
 231
 232	if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
 233		return refcount_dec_if_one(&cp->refcnt);
 234
 235	hash = ip_vs_conn_hashkey_conn(cp);
 236
 237	ct_write_lock_bh(hash);
 238	spin_lock(&cp->lock);
 239
 240	if (cp->flags & IP_VS_CONN_F_HASHED) {
 241		/* Decrease refcnt and unlink conn only if we are last user */
 242		if (refcount_dec_if_one(&cp->refcnt)) {
 243			hlist_del_rcu(&cp->c_list);
 244			cp->flags &= ~IP_VS_CONN_F_HASHED;
 245			ret = true;
 246		}
 247	}
 248
 249	spin_unlock(&cp->lock);
 250	ct_write_unlock_bh(hash);
 251
 252	return ret;
 253}
 254
 255
 256/*
 257 *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 258 *  Called for pkts coming from OUTside-to-INside.
 259 *	p->caddr, p->cport: pkt source address (foreign host)
 260 *	p->vaddr, p->vport: pkt dest address (load balancer)
 261 */
 262static inline struct ip_vs_conn *
 263__ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
 264{
 265	unsigned int hash;
 266	struct ip_vs_conn *cp;
 267
 268	hash = ip_vs_conn_hashkey_param(p, false);
 269
 270	rcu_read_lock();
 271
 272	hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
 273		if (p->cport == cp->cport && p->vport == cp->vport &&
 274		    cp->af == p->af &&
 275		    ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
 276		    ip_vs_addr_equal(p->af, p->vaddr, &cp->vaddr) &&
 277		    ((!p->cport) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
 278		    p->protocol == cp->protocol &&
 279		    cp->ipvs == p->ipvs) {
 280			if (!__ip_vs_conn_get(cp))
 281				continue;
 282			/* HIT */
 283			rcu_read_unlock();
 284			return cp;
 285		}
 286	}
 287
 288	rcu_read_unlock();
 289
 290	return NULL;
 291}
 292
 293struct ip_vs_conn *ip_vs_conn_in_get(const struct ip_vs_conn_param *p)
 294{
 295	struct ip_vs_conn *cp;
 296
 297	cp = __ip_vs_conn_in_get(p);
 298	if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt)) {
 299		struct ip_vs_conn_param cport_zero_p = *p;
 300		cport_zero_p.cport = 0;
 301		cp = __ip_vs_conn_in_get(&cport_zero_p);
 302	}
 303
 304	IP_VS_DBG_BUF(9, "lookup/in %s %s:%d->%s:%d %s\n",
 305		      ip_vs_proto_name(p->protocol),
 306		      IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
 307		      IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
 308		      cp ? "hit" : "not hit");
 309
 310	return cp;
 311}
 312
 313static int
 314ip_vs_conn_fill_param_proto(struct netns_ipvs *ipvs,
 315			    int af, const struct sk_buff *skb,
 316			    const struct ip_vs_iphdr *iph,
 317			    struct ip_vs_conn_param *p)
 318{
 319	__be16 _ports[2], *pptr;
 320
 321	pptr = frag_safe_skb_hp(skb, iph->len, sizeof(_ports), _ports);
 322	if (pptr == NULL)
 323		return 1;
 324
 325	if (likely(!ip_vs_iph_inverse(iph)))
 326		ip_vs_conn_fill_param(ipvs, af, iph->protocol, &iph->saddr,
 327				      pptr[0], &iph->daddr, pptr[1], p);
 328	else
 329		ip_vs_conn_fill_param(ipvs, af, iph->protocol, &iph->daddr,
 330				      pptr[1], &iph->saddr, pptr[0], p);
 331	return 0;
 332}
 333
 334struct ip_vs_conn *
 335ip_vs_conn_in_get_proto(struct netns_ipvs *ipvs, int af,
 336			const struct sk_buff *skb,
 337			const struct ip_vs_iphdr *iph)
 338{
 339	struct ip_vs_conn_param p;
 340
 341	if (ip_vs_conn_fill_param_proto(ipvs, af, skb, iph, &p))
 342		return NULL;
 343
 344	return ip_vs_conn_in_get(&p);
 345}
 346EXPORT_SYMBOL_GPL(ip_vs_conn_in_get_proto);
 347
 348/* Get reference to connection template */
 349struct ip_vs_conn *ip_vs_ct_in_get(const struct ip_vs_conn_param *p)
 350{
 351	unsigned int hash;
 352	struct ip_vs_conn *cp;
 353
 354	hash = ip_vs_conn_hashkey_param(p, false);
 355
 356	rcu_read_lock();
 357
 358	hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
 359		if (unlikely(p->pe_data && p->pe->ct_match)) {
 360			if (cp->ipvs != p->ipvs)
 361				continue;
 362			if (p->pe == cp->pe && p->pe->ct_match(p, cp)) {
 363				if (__ip_vs_conn_get(cp))
 364					goto out;
 365			}
 366			continue;
 367		}
 368
 369		if (cp->af == p->af &&
 370		    ip_vs_addr_equal(p->af, p->caddr, &cp->caddr) &&
 371		    /* protocol should only be IPPROTO_IP if
 372		     * p->vaddr is a fwmark */
 373		    ip_vs_addr_equal(p->protocol == IPPROTO_IP ? AF_UNSPEC :
 374				     p->af, p->vaddr, &cp->vaddr) &&
 375		    p->vport == cp->vport && p->cport == cp->cport &&
 376		    cp->flags & IP_VS_CONN_F_TEMPLATE &&
 377		    p->protocol == cp->protocol &&
 378		    cp->ipvs == p->ipvs) {
 379			if (__ip_vs_conn_get(cp))
 380				goto out;
 381		}
 382	}
 383	cp = NULL;
 384
 385  out:
 386	rcu_read_unlock();
 387
 388	IP_VS_DBG_BUF(9, "template lookup/in %s %s:%d->%s:%d %s\n",
 389		      ip_vs_proto_name(p->protocol),
 390		      IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
 391		      IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
 392		      cp ? "hit" : "not hit");
 393
 394	return cp;
 395}
 396
 397/* Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
 398 * Called for pkts coming from inside-to-OUTside.
 399 *	p->caddr, p->cport: pkt source address (inside host)
 400 *	p->vaddr, p->vport: pkt dest address (foreign host) */
 401struct ip_vs_conn *ip_vs_conn_out_get(const struct ip_vs_conn_param *p)
 402{
 403	unsigned int hash;
 404	struct ip_vs_conn *cp, *ret=NULL;
 405
 406	/*
 407	 *	Check for "full" addressed entries
 408	 */
 409	hash = ip_vs_conn_hashkey_param(p, true);
 410
 411	rcu_read_lock();
 412
 413	hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
 414		if (p->vport == cp->cport && p->cport == cp->dport &&
 415		    cp->af == p->af &&
 416		    ip_vs_addr_equal(p->af, p->vaddr, &cp->caddr) &&
 417		    ip_vs_addr_equal(p->af, p->caddr, &cp->daddr) &&
 418		    p->protocol == cp->protocol &&
 419		    cp->ipvs == p->ipvs) {
 420			if (!__ip_vs_conn_get(cp))
 421				continue;
 422			/* HIT */
 423			ret = cp;
 424			break;
 425		}
 426	}
 427
 428	rcu_read_unlock();
 429
 430	IP_VS_DBG_BUF(9, "lookup/out %s %s:%d->%s:%d %s\n",
 431		      ip_vs_proto_name(p->protocol),
 432		      IP_VS_DBG_ADDR(p->af, p->caddr), ntohs(p->cport),
 433		      IP_VS_DBG_ADDR(p->af, p->vaddr), ntohs(p->vport),
 434		      ret ? "hit" : "not hit");
 435
 436	return ret;
 437}
 438
 439struct ip_vs_conn *
 440ip_vs_conn_out_get_proto(struct netns_ipvs *ipvs, int af,
 441			 const struct sk_buff *skb,
 442			 const struct ip_vs_iphdr *iph)
 443{
 444	struct ip_vs_conn_param p;
 445
 446	if (ip_vs_conn_fill_param_proto(ipvs, af, skb, iph, &p))
 447		return NULL;
 448
 449	return ip_vs_conn_out_get(&p);
 450}
 451EXPORT_SYMBOL_GPL(ip_vs_conn_out_get_proto);
 452
 453/*
 454 *      Put back the conn and restart its timer with its timeout
 455 */
 456static void __ip_vs_conn_put_timer(struct ip_vs_conn *cp)
 457{
 458	unsigned long t = (cp->flags & IP_VS_CONN_F_ONE_PACKET) ?
 459		0 : cp->timeout;
 460	mod_timer(&cp->timer, jiffies+t);
 461
 462	__ip_vs_conn_put(cp);
 463}
 464
 465void ip_vs_conn_put(struct ip_vs_conn *cp)
 466{
 467	if ((cp->flags & IP_VS_CONN_F_ONE_PACKET) &&
 468	    (refcount_read(&cp->refcnt) == 1) &&
 469	    !timer_pending(&cp->timer))
 470		/* expire connection immediately */
 471		ip_vs_conn_expire(&cp->timer);
 472	else
 473		__ip_vs_conn_put_timer(cp);
 474}
 475
 476/*
 477 *	Fill a no_client_port connection with a client port number
 478 */
 479void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
 480{
 481	if (ip_vs_conn_unhash(cp)) {
 482		spin_lock_bh(&cp->lock);
 483		if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
 484			atomic_dec(&ip_vs_conn_no_cport_cnt);
 485			cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
 486			cp->cport = cport;
 487		}
 488		spin_unlock_bh(&cp->lock);
 489
 490		/* hash on new dport */
 491		ip_vs_conn_hash(cp);
 492	}
 493}
 494
 495
 496/*
 497 *	Bind a connection entry with the corresponding packet_xmit.
 498 *	Called by ip_vs_conn_new.
 499 */
 500static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
 501{
 502	switch (IP_VS_FWD_METHOD(cp)) {
 503	case IP_VS_CONN_F_MASQ:
 504		cp->packet_xmit = ip_vs_nat_xmit;
 505		break;
 506
 507	case IP_VS_CONN_F_TUNNEL:
 508#ifdef CONFIG_IP_VS_IPV6
 509		if (cp->daf == AF_INET6)
 510			cp->packet_xmit = ip_vs_tunnel_xmit_v6;
 511		else
 512#endif
 513			cp->packet_xmit = ip_vs_tunnel_xmit;
 514		break;
 515
 516	case IP_VS_CONN_F_DROUTE:
 517		cp->packet_xmit = ip_vs_dr_xmit;
 518		break;
 519
 520	case IP_VS_CONN_F_LOCALNODE:
 521		cp->packet_xmit = ip_vs_null_xmit;
 522		break;
 523
 524	case IP_VS_CONN_F_BYPASS:
 525		cp->packet_xmit = ip_vs_bypass_xmit;
 526		break;
 527	}
 528}
 529
 530#ifdef CONFIG_IP_VS_IPV6
 531static inline void ip_vs_bind_xmit_v6(struct ip_vs_conn *cp)
 532{
 533	switch (IP_VS_FWD_METHOD(cp)) {
 534	case IP_VS_CONN_F_MASQ:
 535		cp->packet_xmit = ip_vs_nat_xmit_v6;
 536		break;
 537
 538	case IP_VS_CONN_F_TUNNEL:
 539		if (cp->daf == AF_INET6)
 540			cp->packet_xmit = ip_vs_tunnel_xmit_v6;
 541		else
 542			cp->packet_xmit = ip_vs_tunnel_xmit;
 543		break;
 544
 545	case IP_VS_CONN_F_DROUTE:
 546		cp->packet_xmit = ip_vs_dr_xmit_v6;
 547		break;
 548
 549	case IP_VS_CONN_F_LOCALNODE:
 550		cp->packet_xmit = ip_vs_null_xmit;
 551		break;
 552
 553	case IP_VS_CONN_F_BYPASS:
 554		cp->packet_xmit = ip_vs_bypass_xmit_v6;
 555		break;
 556	}
 557}
 558#endif
 559
 560
 561static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
 562{
 563	return atomic_read(&dest->activeconns)
 564		+ atomic_read(&dest->inactconns);
 565}
 566
 567/*
 568 *	Bind a connection entry with a virtual service destination
 569 *	Called just after a new connection entry is created.
 570 */
 571static inline void
 572ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 573{
 574	unsigned int conn_flags;
 575	__u32 flags;
 576
 577	/* if dest is NULL, then return directly */
 578	if (!dest)
 579		return;
 580
 581	/* Increase the refcnt counter of the dest */
 582	ip_vs_dest_hold(dest);
 583
 584	conn_flags = atomic_read(&dest->conn_flags);
 585	if (cp->protocol != IPPROTO_UDP)
 586		conn_flags &= ~IP_VS_CONN_F_ONE_PACKET;
 587	flags = cp->flags;
 588	/* Bind with the destination and its corresponding transmitter */
 589	if (flags & IP_VS_CONN_F_SYNC) {
 590		/* if the connection is not template and is created
 591		 * by sync, preserve the activity flag.
 592		 */
 593		if (!(flags & IP_VS_CONN_F_TEMPLATE))
 594			conn_flags &= ~IP_VS_CONN_F_INACTIVE;
 595		/* connections inherit forwarding method from dest */
 596		flags &= ~(IP_VS_CONN_F_FWD_MASK | IP_VS_CONN_F_NOOUTPUT);
 597	}
 598	flags |= conn_flags;
 599	cp->flags = flags;
 600	cp->dest = dest;
 601
 602	IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
 603		      "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 604		      "dest->refcnt:%d\n",
 605		      ip_vs_proto_name(cp->protocol),
 606		      IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 607		      IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 608		      IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
 609		      ip_vs_fwd_tag(cp), cp->state,
 610		      cp->flags, refcount_read(&cp->refcnt),
 611		      refcount_read(&dest->refcnt));
 612
 613	/* Update the connection counters */
 614	if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
 615		/* It is a normal connection, so modify the counters
 616		 * according to the flags, later the protocol can
 617		 * update them on state change
 618		 */
 619		if (!(flags & IP_VS_CONN_F_INACTIVE))
 620			atomic_inc(&dest->activeconns);
 621		else
 622			atomic_inc(&dest->inactconns);
 623	} else {
 624		/* It is a persistent connection/template, so increase
 625		   the persistent connection counter */
 626		atomic_inc(&dest->persistconns);
 627	}
 628
 629	if (dest->u_threshold != 0 &&
 630	    ip_vs_dest_totalconns(dest) >= dest->u_threshold)
 631		dest->flags |= IP_VS_DEST_F_OVERLOAD;
 632}
 633
 634
 635/*
 636 * Check if there is a destination for the connection, if so
 637 * bind the connection to the destination.
 638 */
 639void ip_vs_try_bind_dest(struct ip_vs_conn *cp)
 640{
 641	struct ip_vs_dest *dest;
 642
 643	rcu_read_lock();
 644
 645	/* This function is only invoked by the synchronization code. We do
 646	 * not currently support heterogeneous pools with synchronization,
 647	 * so we can make the assumption that the svc_af is the same as the
 648	 * dest_af
 649	 */
 650	dest = ip_vs_find_dest(cp->ipvs, cp->af, cp->af, &cp->daddr,
 651			       cp->dport, &cp->vaddr, cp->vport,
 652			       cp->protocol, cp->fwmark, cp->flags);
 653	if (dest) {
 654		struct ip_vs_proto_data *pd;
 655
 656		spin_lock_bh(&cp->lock);
 657		if (cp->dest) {
 658			spin_unlock_bh(&cp->lock);
 659			rcu_read_unlock();
 660			return;
 661		}
 662
 663		/* Applications work depending on the forwarding method
 664		 * but better to reassign them always when binding dest */
 665		if (cp->app)
 666			ip_vs_unbind_app(cp);
 667
 668		ip_vs_bind_dest(cp, dest);
 669		spin_unlock_bh(&cp->lock);
 670
 671		/* Update its packet transmitter */
 672		cp->packet_xmit = NULL;
 673#ifdef CONFIG_IP_VS_IPV6
 674		if (cp->af == AF_INET6)
 675			ip_vs_bind_xmit_v6(cp);
 676		else
 677#endif
 678			ip_vs_bind_xmit(cp);
 679
 680		pd = ip_vs_proto_data_get(cp->ipvs, cp->protocol);
 681		if (pd && atomic_read(&pd->appcnt))
 682			ip_vs_bind_app(cp, pd->pp);
 683	}
 684	rcu_read_unlock();
 685}
 686
 687
 688/*
 689 *	Unbind a connection entry with its VS destination
 690 *	Called by the ip_vs_conn_expire function.
 691 */
 692static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
 693{
 694	struct ip_vs_dest *dest = cp->dest;
 695
 696	if (!dest)
 697		return;
 698
 699	IP_VS_DBG_BUF(7, "Unbind-dest %s c:%s:%d v:%s:%d "
 700		      "d:%s:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
 701		      "dest->refcnt:%d\n",
 702		      ip_vs_proto_name(cp->protocol),
 703		      IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
 704		      IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
 705		      IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
 706		      ip_vs_fwd_tag(cp), cp->state,
 707		      cp->flags, refcount_read(&cp->refcnt),
 708		      refcount_read(&dest->refcnt));
 709
 710	/* Update the connection counters */
 711	if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
 712		/* It is a normal connection, so decrease the inactconns
 713		   or activeconns counter */
 714		if (cp->flags & IP_VS_CONN_F_INACTIVE) {
 715			atomic_dec(&dest->inactconns);
 716		} else {
 717			atomic_dec(&dest->activeconns);
 718		}
 719	} else {
 720		/* It is a persistent connection/template, so decrease
 721		   the persistent connection counter */
 722		atomic_dec(&dest->persistconns);
 723	}
 724
 725	if (dest->l_threshold != 0) {
 726		if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
 727			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 728	} else if (dest->u_threshold != 0) {
 729		if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
 730			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 731	} else {
 732		if (dest->flags & IP_VS_DEST_F_OVERLOAD)
 733			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 734	}
 735
 736	ip_vs_dest_put(dest);
 737}
 738
 739static int expire_quiescent_template(struct netns_ipvs *ipvs,
 740				     struct ip_vs_dest *dest)
 741{
 742#ifdef CONFIG_SYSCTL
 743	return ipvs->sysctl_expire_quiescent_template &&
 744		(atomic_read(&dest->weight) == 0);
 745#else
 746	return 0;
 747#endif
 748}
 749
 750/*
 751 *	Checking if the destination of a connection template is available.
 752 *	If available, return 1, otherwise invalidate this connection
 753 *	template and return 0.
 754 */
 755int ip_vs_check_template(struct ip_vs_conn *ct, struct ip_vs_dest *cdest)
 756{
 757	struct ip_vs_dest *dest = ct->dest;
 758	struct netns_ipvs *ipvs = ct->ipvs;
 759
 760	/*
 761	 * Checking the dest server status.
 762	 */
 763	if ((dest == NULL) ||
 764	    !(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
 765	    expire_quiescent_template(ipvs, dest) ||
 766	    (cdest && (dest != cdest))) {
 767		IP_VS_DBG_BUF(9, "check_template: dest not available for "
 768			      "protocol %s s:%s:%d v:%s:%d "
 769			      "-> d:%s:%d\n",
 770			      ip_vs_proto_name(ct->protocol),
 771			      IP_VS_DBG_ADDR(ct->af, &ct->caddr),
 772			      ntohs(ct->cport),
 773			      IP_VS_DBG_ADDR(ct->af, &ct->vaddr),
 774			      ntohs(ct->vport),
 775			      IP_VS_DBG_ADDR(ct->daf, &ct->daddr),
 776			      ntohs(ct->dport));
 777
 778		/*
 779		 * Invalidate the connection template
 780		 */
 781		if (ct->vport != htons(0xffff)) {
 782			if (ip_vs_conn_unhash(ct)) {
 783				ct->dport = htons(0xffff);
 784				ct->vport = htons(0xffff);
 785				ct->cport = 0;
 786				ip_vs_conn_hash(ct);
 787			}
 788		}
 789
 790		/*
 791		 * Simply decrease the refcnt of the template,
 792		 * don't restart its timer.
 793		 */
 794		__ip_vs_conn_put(ct);
 795		return 0;
 796	}
 797	return 1;
 798}
 799
 800static void ip_vs_conn_rcu_free(struct rcu_head *head)
 801{
 802	struct ip_vs_conn *cp = container_of(head, struct ip_vs_conn,
 803					     rcu_head);
 804
 805	ip_vs_pe_put(cp->pe);
 806	kfree(cp->pe_data);
 807	kmem_cache_free(ip_vs_conn_cachep, cp);
 808}
 809
 810static void ip_vs_conn_expire(struct timer_list *t)
 811{
 812	struct ip_vs_conn *cp = from_timer(cp, t, timer);
 813	struct netns_ipvs *ipvs = cp->ipvs;
 814
 815	/*
 816	 *	do I control anybody?
 817	 */
 818	if (atomic_read(&cp->n_control))
 819		goto expire_later;
 820
 821	/* Unlink conn if not referenced anymore */
 822	if (likely(ip_vs_conn_unlink(cp))) {
 823		struct ip_vs_conn *ct = cp->control;
 824
 825		/* delete the timer if it is activated by other users */
 826		del_timer(&cp->timer);
 827
 828		/* does anybody control me? */
 829		if (ct) {
 830			ip_vs_control_del(cp);
 831			/* Drop CTL or non-assured TPL if not used anymore */
 832			if (!cp->timeout && !atomic_read(&ct->n_control) &&
 833			    (!(ct->flags & IP_VS_CONN_F_TEMPLATE) ||
 834			     !(ct->state & IP_VS_CTPL_S_ASSURED))) {
 835				IP_VS_DBG(4, "drop controlling connection\n");
 836				ct->timeout = 0;
 837				ip_vs_conn_expire_now(ct);
 838			}
 839		}
 840
 841		if ((cp->flags & IP_VS_CONN_F_NFCT) &&
 842		    !(cp->flags & IP_VS_CONN_F_ONE_PACKET)) {
 843			/* Do not access conntracks during subsys cleanup
 844			 * because nf_conntrack_find_get can not be used after
 845			 * conntrack cleanup for the net.
 846			 */
 847			smp_rmb();
 848			if (ipvs->enable)
 849				ip_vs_conn_drop_conntrack(cp);
 850		}
 851
 852		if (unlikely(cp->app != NULL))
 853			ip_vs_unbind_app(cp);
 854		ip_vs_unbind_dest(cp);
 855		if (cp->flags & IP_VS_CONN_F_NO_CPORT)
 856			atomic_dec(&ip_vs_conn_no_cport_cnt);
 857		if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
 858			ip_vs_conn_rcu_free(&cp->rcu_head);
 859		else
 860			call_rcu(&cp->rcu_head, ip_vs_conn_rcu_free);
 861		atomic_dec(&ipvs->conn_count);
 862		return;
 863	}
 864
 865  expire_later:
 866	IP_VS_DBG(7, "delayed: conn->refcnt=%d conn->n_control=%d\n",
 867		  refcount_read(&cp->refcnt),
 868		  atomic_read(&cp->n_control));
 869
 870	refcount_inc(&cp->refcnt);
 871	cp->timeout = 60*HZ;
 872
 873	if (ipvs->sync_state & IP_VS_STATE_MASTER)
 874		ip_vs_sync_conn(ipvs, cp, sysctl_sync_threshold(ipvs));
 875
 876	__ip_vs_conn_put_timer(cp);
 877}
 878
 879/* Modify timer, so that it expires as soon as possible.
 880 * Can be called without reference only if under RCU lock.
 881 * We can have such chain of conns linked with ->control: DATA->CTL->TPL
 882 * - DATA (eg. FTP) and TPL (persistence) can be present depending on setup
 883 * - cp->timeout=0 indicates all conns from chain should be dropped but
 884 * TPL is not dropped if in assured state
 885 */
 886void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
 887{
 888	/* Using mod_timer_pending will ensure the timer is not
 889	 * modified after the final del_timer in ip_vs_conn_expire.
 890	 */
 891	if (timer_pending(&cp->timer) &&
 892	    time_after(cp->timer.expires, jiffies))
 893		mod_timer_pending(&cp->timer, jiffies);
 894}
 895
 896
 897/*
 898 *	Create a new connection entry and hash it into the ip_vs_conn_tab
 899 */
 900struct ip_vs_conn *
 901ip_vs_conn_new(const struct ip_vs_conn_param *p, int dest_af,
 902	       const union nf_inet_addr *daddr, __be16 dport, unsigned int flags,
 903	       struct ip_vs_dest *dest, __u32 fwmark)
 904{
 905	struct ip_vs_conn *cp;
 906	struct netns_ipvs *ipvs = p->ipvs;
 907	struct ip_vs_proto_data *pd = ip_vs_proto_data_get(p->ipvs,
 908							   p->protocol);
 909
 910	cp = kmem_cache_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
 911	if (cp == NULL) {
 912		IP_VS_ERR_RL("%s(): no memory\n", __func__);
 913		return NULL;
 914	}
 915
 916	INIT_HLIST_NODE(&cp->c_list);
 917	timer_setup(&cp->timer, ip_vs_conn_expire, 0);
 918	cp->ipvs	   = ipvs;
 919	cp->af		   = p->af;
 920	cp->daf		   = dest_af;
 921	cp->protocol	   = p->protocol;
 922	ip_vs_addr_set(p->af, &cp->caddr, p->caddr);
 923	cp->cport	   = p->cport;
 924	/* proto should only be IPPROTO_IP if p->vaddr is a fwmark */
 925	ip_vs_addr_set(p->protocol == IPPROTO_IP ? AF_UNSPEC : p->af,
 926		       &cp->vaddr, p->vaddr);
 927	cp->vport	   = p->vport;
 928	ip_vs_addr_set(cp->daf, &cp->daddr, daddr);
 929	cp->dport          = dport;
 930	cp->flags	   = flags;
 931	cp->fwmark         = fwmark;
 932	if (flags & IP_VS_CONN_F_TEMPLATE && p->pe) {
 933		ip_vs_pe_get(p->pe);
 934		cp->pe = p->pe;
 935		cp->pe_data = p->pe_data;
 936		cp->pe_data_len = p->pe_data_len;
 937	} else {
 938		cp->pe = NULL;
 939		cp->pe_data = NULL;
 940		cp->pe_data_len = 0;
 941	}
 942	spin_lock_init(&cp->lock);
 943
 944	/*
 945	 * Set the entry is referenced by the current thread before hashing
 946	 * it in the table, so that other thread run ip_vs_random_dropentry
 947	 * but cannot drop this entry.
 948	 */
 949	refcount_set(&cp->refcnt, 1);
 950
 951	cp->control = NULL;
 952	atomic_set(&cp->n_control, 0);
 953	atomic_set(&cp->in_pkts, 0);
 954
 955	cp->packet_xmit = NULL;
 956	cp->app = NULL;
 957	cp->app_data = NULL;
 958	/* reset struct ip_vs_seq */
 959	cp->in_seq.delta = 0;
 960	cp->out_seq.delta = 0;
 961
 962	atomic_inc(&ipvs->conn_count);
 963	if (flags & IP_VS_CONN_F_NO_CPORT)
 964		atomic_inc(&ip_vs_conn_no_cport_cnt);
 965
 966	/* Bind the connection with a destination server */
 967	cp->dest = NULL;
 968	ip_vs_bind_dest(cp, dest);
 969
 970	/* Set its state and timeout */
 971	cp->state = 0;
 972	cp->old_state = 0;
 973	cp->timeout = 3*HZ;
 974	cp->sync_endtime = jiffies & ~3UL;
 975
 976	/* Bind its packet transmitter */
 977#ifdef CONFIG_IP_VS_IPV6
 978	if (p->af == AF_INET6)
 979		ip_vs_bind_xmit_v6(cp);
 980	else
 981#endif
 982		ip_vs_bind_xmit(cp);
 983
 984	if (unlikely(pd && atomic_read(&pd->appcnt)))
 985		ip_vs_bind_app(cp, pd->pp);
 986
 987	/*
 988	 * Allow conntrack to be preserved. By default, conntrack
 989	 * is created and destroyed for every packet.
 990	 * Sometimes keeping conntrack can be useful for
 991	 * IP_VS_CONN_F_ONE_PACKET too.
 992	 */
 993
 994	if (ip_vs_conntrack_enabled(ipvs))
 995		cp->flags |= IP_VS_CONN_F_NFCT;
 996
 997	/* Hash it in the ip_vs_conn_tab finally */
 998	ip_vs_conn_hash(cp);
 999
1000	return cp;
1001}
1002
1003/*
1004 *	/proc/net/ip_vs_conn entries
1005 */
1006#ifdef CONFIG_PROC_FS
1007struct ip_vs_iter_state {
1008	struct seq_net_private	p;
1009	struct hlist_head	*l;
1010};
1011
1012static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
1013{
1014	int idx;
1015	struct ip_vs_conn *cp;
1016	struct ip_vs_iter_state *iter = seq->private;
1017
1018	for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1019		hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1020			/* __ip_vs_conn_get() is not needed by
1021			 * ip_vs_conn_seq_show and ip_vs_conn_sync_seq_show
1022			 */
1023			if (pos-- == 0) {
1024				iter->l = &ip_vs_conn_tab[idx];
1025				return cp;
1026			}
1027		}
1028		cond_resched_rcu();
1029	}
1030
1031	return NULL;
1032}
1033
1034static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
1035	__acquires(RCU)
1036{
1037	struct ip_vs_iter_state *iter = seq->private;
1038
1039	iter->l = NULL;
1040	rcu_read_lock();
1041	return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
1042}
1043
1044static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1045{
1046	struct ip_vs_conn *cp = v;
1047	struct ip_vs_iter_state *iter = seq->private;
1048	struct hlist_node *e;
1049	struct hlist_head *l = iter->l;
1050	int idx;
1051
1052	++*pos;
1053	if (v == SEQ_START_TOKEN)
1054		return ip_vs_conn_array(seq, 0);
1055
1056	/* more on same hash chain? */
1057	e = rcu_dereference(hlist_next_rcu(&cp->c_list));
1058	if (e)
1059		return hlist_entry(e, struct ip_vs_conn, c_list);
1060
1061	idx = l - ip_vs_conn_tab;
1062	while (++idx < ip_vs_conn_tab_size) {
1063		hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1064			iter->l = &ip_vs_conn_tab[idx];
1065			return cp;
1066		}
1067		cond_resched_rcu();
1068	}
1069	iter->l = NULL;
1070	return NULL;
1071}
1072
1073static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
1074	__releases(RCU)
1075{
1076	rcu_read_unlock();
1077}
1078
1079static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
1080{
1081
1082	if (v == SEQ_START_TOKEN)
1083		seq_puts(seq,
1084   "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Expires PEName PEData\n");
1085	else {
1086		const struct ip_vs_conn *cp = v;
1087		struct net *net = seq_file_net(seq);
1088		char pe_data[IP_VS_PENAME_MAXLEN + IP_VS_PEDATA_MAXLEN + 3];
1089		size_t len = 0;
1090		char dbuf[IP_VS_ADDRSTRLEN];
1091
1092		if (!net_eq(cp->ipvs->net, net))
1093			return 0;
1094		if (cp->pe_data) {
1095			pe_data[0] = ' ';
1096			len = strlen(cp->pe->name);
1097			memcpy(pe_data + 1, cp->pe->name, len);
1098			pe_data[len + 1] = ' ';
1099			len += 2;
1100			len += cp->pe->show_pe_data(cp, pe_data + len);
1101		}
1102		pe_data[len] = '\0';
1103
1104#ifdef CONFIG_IP_VS_IPV6
1105		if (cp->daf == AF_INET6)
1106			snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1107		else
1108#endif
1109			snprintf(dbuf, sizeof(dbuf), "%08X",
1110				 ntohl(cp->daddr.ip));
1111
1112#ifdef CONFIG_IP_VS_IPV6
1113		if (cp->af == AF_INET6)
1114			seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1115				"%s %04X %-11s %7u%s\n",
1116				ip_vs_proto_name(cp->protocol),
1117				&cp->caddr.in6, ntohs(cp->cport),
1118				&cp->vaddr.in6, ntohs(cp->vport),
1119				dbuf, ntohs(cp->dport),
1120				ip_vs_state_name(cp),
1121				jiffies_delta_to_msecs(cp->timer.expires -
1122						       jiffies) / 1000,
1123				pe_data);
1124		else
1125#endif
1126			seq_printf(seq,
1127				"%-3s %08X %04X %08X %04X"
1128				" %s %04X %-11s %7u%s\n",
1129				ip_vs_proto_name(cp->protocol),
1130				ntohl(cp->caddr.ip), ntohs(cp->cport),
1131				ntohl(cp->vaddr.ip), ntohs(cp->vport),
1132				dbuf, ntohs(cp->dport),
1133				ip_vs_state_name(cp),
1134				jiffies_delta_to_msecs(cp->timer.expires -
1135						       jiffies) / 1000,
1136				pe_data);
1137	}
1138	return 0;
1139}
1140
1141static const struct seq_operations ip_vs_conn_seq_ops = {
1142	.start = ip_vs_conn_seq_start,
1143	.next  = ip_vs_conn_seq_next,
1144	.stop  = ip_vs_conn_seq_stop,
1145	.show  = ip_vs_conn_seq_show,
1146};
1147
1148static const char *ip_vs_origin_name(unsigned int flags)
1149{
1150	if (flags & IP_VS_CONN_F_SYNC)
1151		return "SYNC";
1152	else
1153		return "LOCAL";
1154}
1155
1156static int ip_vs_conn_sync_seq_show(struct seq_file *seq, void *v)
1157{
1158	char dbuf[IP_VS_ADDRSTRLEN];
1159
1160	if (v == SEQ_START_TOKEN)
1161		seq_puts(seq,
1162   "Pro FromIP   FPrt ToIP     TPrt DestIP   DPrt State       Origin Expires\n");
1163	else {
1164		const struct ip_vs_conn *cp = v;
1165		struct net *net = seq_file_net(seq);
1166
1167		if (!net_eq(cp->ipvs->net, net))
1168			return 0;
1169
1170#ifdef CONFIG_IP_VS_IPV6
1171		if (cp->daf == AF_INET6)
1172			snprintf(dbuf, sizeof(dbuf), "%pI6", &cp->daddr.in6);
1173		else
1174#endif
1175			snprintf(dbuf, sizeof(dbuf), "%08X",
1176				 ntohl(cp->daddr.ip));
1177
1178#ifdef CONFIG_IP_VS_IPV6
1179		if (cp->af == AF_INET6)
1180			seq_printf(seq, "%-3s %pI6 %04X %pI6 %04X "
1181				"%s %04X %-11s %-6s %7u\n",
1182				ip_vs_proto_name(cp->protocol),
1183				&cp->caddr.in6, ntohs(cp->cport),
1184				&cp->vaddr.in6, ntohs(cp->vport),
1185				dbuf, ntohs(cp->dport),
1186				ip_vs_state_name(cp),
1187				ip_vs_origin_name(cp->flags),
1188				jiffies_delta_to_msecs(cp->timer.expires -
1189						       jiffies) / 1000);
1190		else
1191#endif
1192			seq_printf(seq,
1193				"%-3s %08X %04X %08X %04X "
1194				"%s %04X %-11s %-6s %7u\n",
1195				ip_vs_proto_name(cp->protocol),
1196				ntohl(cp->caddr.ip), ntohs(cp->cport),
1197				ntohl(cp->vaddr.ip), ntohs(cp->vport),
1198				dbuf, ntohs(cp->dport),
1199				ip_vs_state_name(cp),
1200				ip_vs_origin_name(cp->flags),
1201				jiffies_delta_to_msecs(cp->timer.expires -
1202						       jiffies) / 1000);
1203	}
1204	return 0;
1205}
1206
1207static const struct seq_operations ip_vs_conn_sync_seq_ops = {
1208	.start = ip_vs_conn_seq_start,
1209	.next  = ip_vs_conn_seq_next,
1210	.stop  = ip_vs_conn_seq_stop,
1211	.show  = ip_vs_conn_sync_seq_show,
1212};
1213#endif
1214
1215
1216/* Randomly drop connection entries before running out of memory
1217 * Can be used for DATA and CTL conns. For TPL conns there are exceptions:
1218 * - traffic for services in OPS mode increases ct->in_pkts, so it is supported
1219 * - traffic for services not in OPS mode does not increase ct->in_pkts in
1220 * all cases, so it is not supported
1221 */
1222static inline int todrop_entry(struct ip_vs_conn *cp)
1223{
1224	/*
1225	 * The drop rate array needs tuning for real environments.
1226	 * Called from timer bh only => no locking
1227	 */
1228	static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
1229	static char todrop_counter[9] = {0};
1230	int i;
1231
1232	/* if the conn entry hasn't lasted for 60 seconds, don't drop it.
1233	   This will leave enough time for normal connection to get
1234	   through. */
1235	if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
1236		return 0;
1237
1238	/* Don't drop the entry if its number of incoming packets is not
1239	   located in [0, 8] */
1240	i = atomic_read(&cp->in_pkts);
1241	if (i > 8 || i < 0) return 0;
1242
1243	if (!todrop_rate[i]) return 0;
1244	if (--todrop_counter[i] > 0) return 0;
1245
1246	todrop_counter[i] = todrop_rate[i];
1247	return 1;
1248}
1249
1250static inline bool ip_vs_conn_ops_mode(struct ip_vs_conn *cp)
1251{
1252	struct ip_vs_service *svc;
1253
1254	if (!cp->dest)
1255		return false;
1256	svc = rcu_dereference(cp->dest->svc);
1257	return svc && (svc->flags & IP_VS_SVC_F_ONEPACKET);
1258}
1259
1260/* Called from keventd and must protect itself from softirqs */
1261void ip_vs_random_dropentry(struct netns_ipvs *ipvs)
1262{
1263	int idx;
1264	struct ip_vs_conn *cp;
1265
1266	rcu_read_lock();
1267	/*
1268	 * Randomly scan 1/32 of the whole table every second
1269	 */
1270	for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
1271		unsigned int hash = prandom_u32() & ip_vs_conn_tab_mask;
1272
1273		hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
1274			if (cp->ipvs != ipvs)
1275				continue;
1276			if (atomic_read(&cp->n_control))
1277				continue;
1278			if (cp->flags & IP_VS_CONN_F_TEMPLATE) {
1279				/* connection template of OPS */
1280				if (ip_vs_conn_ops_mode(cp))
1281					goto try_drop;
1282				if (!(cp->state & IP_VS_CTPL_S_ASSURED))
1283					goto drop;
1284				continue;
1285			}
1286			if (cp->protocol == IPPROTO_TCP) {
1287				switch(cp->state) {
1288				case IP_VS_TCP_S_SYN_RECV:
1289				case IP_VS_TCP_S_SYNACK:
1290					break;
1291
1292				case IP_VS_TCP_S_ESTABLISHED:
1293					if (todrop_entry(cp))
1294						break;
1295					continue;
1296
1297				default:
1298					continue;
1299				}
1300			} else if (cp->protocol == IPPROTO_SCTP) {
1301				switch (cp->state) {
1302				case IP_VS_SCTP_S_INIT1:
1303				case IP_VS_SCTP_S_INIT:
1304					break;
1305				case IP_VS_SCTP_S_ESTABLISHED:
1306					if (todrop_entry(cp))
1307						break;
1308					continue;
1309				default:
1310					continue;
1311				}
1312			} else {
1313try_drop:
1314				if (!todrop_entry(cp))
1315					continue;
1316			}
1317
1318drop:
1319			IP_VS_DBG(4, "drop connection\n");
1320			cp->timeout = 0;
1321			ip_vs_conn_expire_now(cp);
1322		}
1323		cond_resched_rcu();
1324	}
1325	rcu_read_unlock();
1326}
1327
1328
1329/*
1330 *      Flush all the connection entries in the ip_vs_conn_tab
1331 */
1332static void ip_vs_conn_flush(struct netns_ipvs *ipvs)
1333{
1334	int idx;
1335	struct ip_vs_conn *cp, *cp_c;
1336
1337flush_again:
1338	rcu_read_lock();
1339	for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
1340
1341		hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
1342			if (cp->ipvs != ipvs)
1343				continue;
1344			/* As timers are expired in LIFO order, restart
1345			 * the timer of controlling connection first, so
1346			 * that it is expired after us.
1347			 */
1348			cp_c = cp->control;
1349			/* cp->control is valid only with reference to cp */
1350			if (cp_c && __ip_vs_conn_get(cp)) {
1351				IP_VS_DBG(4, "del controlling connection\n");
1352				ip_vs_conn_expire_now(cp_c);
1353				__ip_vs_conn_put(cp);
1354			}
1355			IP_VS_DBG(4, "del connection\n");
1356			ip_vs_conn_expire_now(cp);
1357		}
1358		cond_resched_rcu();
1359	}
1360	rcu_read_unlock();
1361
1362	/* the counter may be not NULL, because maybe some conn entries
1363	   are run by slow timer handler or unhashed but still referred */
1364	if (atomic_read(&ipvs->conn_count) != 0) {
1365		schedule();
1366		goto flush_again;
1367	}
1368}
1369/*
1370 * per netns init and exit
1371 */
1372int __net_init ip_vs_conn_net_init(struct netns_ipvs *ipvs)
1373{
1374	atomic_set(&ipvs->conn_count, 0);
1375
1376	proc_create_net("ip_vs_conn", 0, ipvs->net->proc_net,
1377			&ip_vs_conn_seq_ops, sizeof(struct ip_vs_iter_state));
1378	proc_create_net("ip_vs_conn_sync", 0, ipvs->net->proc_net,
1379			&ip_vs_conn_sync_seq_ops,
1380			sizeof(struct ip_vs_iter_state));
1381	return 0;
1382}
1383
1384void __net_exit ip_vs_conn_net_cleanup(struct netns_ipvs *ipvs)
1385{
1386	/* flush all the connection entries first */
1387	ip_vs_conn_flush(ipvs);
1388	remove_proc_entry("ip_vs_conn", ipvs->net->proc_net);
1389	remove_proc_entry("ip_vs_conn_sync", ipvs->net->proc_net);
1390}
1391
1392int __init ip_vs_conn_init(void)
1393{
1394	int idx;
1395
1396	/* Compute size and mask */
1397	ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits;
1398	ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;
1399
1400	/*
1401	 * Allocate the connection hash table and initialize its list heads
1402	 */
1403	ip_vs_conn_tab = vmalloc(array_size(ip_vs_conn_tab_size,
1404					    sizeof(*ip_vs_conn_tab)));
1405	if (!ip_vs_conn_tab)
1406		return -ENOMEM;
1407
1408	/* Allocate ip_vs_conn slab cache */
1409	ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
1410					      sizeof(struct ip_vs_conn), 0,
1411					      SLAB_HWCACHE_ALIGN, NULL);
1412	if (!ip_vs_conn_cachep) {
1413		vfree(ip_vs_conn_tab);
1414		return -ENOMEM;
1415	}
1416
1417	pr_info("Connection hash table configured "
1418		"(size=%d, memory=%ldKbytes)\n",
1419		ip_vs_conn_tab_size,
1420		(long)(ip_vs_conn_tab_size*sizeof(struct list_head))/1024);
1421	IP_VS_DBG(0, "Each connection entry needs %zd bytes at least\n",
1422		  sizeof(struct ip_vs_conn));
1423
1424	for (idx = 0; idx < ip_vs_conn_tab_size; idx++)
1425		INIT_HLIST_HEAD(&ip_vs_conn_tab[idx]);
1426
1427	for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++)  {
1428		spin_lock_init(&__ip_vs_conntbl_lock_array[idx].l);
1429	}
1430
1431	/* calculate the random value for connection hash */
1432	get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
1433
1434	return 0;
1435}
1436
1437void ip_vs_conn_cleanup(void)
1438{
1439	/* Wait all ip_vs_conn_rcu_free() callbacks to complete */
1440	rcu_barrier();
1441	/* Release the empty cache */
1442	kmem_cache_destroy(ip_vs_conn_cachep);
1443	vfree(ip_vs_conn_tab);
1444}