1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * INET		An implementation of the TCP/IP protocol suite for the LINUX
   4 *		operating system.  INET is implemented using the  BSD Socket
   5 *		interface as the means of communication with the user level.
   6 *
   7 *		IPv4 Forwarding Information Base: semantics.
   8 *
   9 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10 */
  11
  12#include <linux/uaccess.h>
  13#include <linux/bitops.h>
  14#include <linux/types.h>
  15#include <linux/kernel.h>
  16#include <linux/jiffies.h>
  17#include <linux/mm.h>
  18#include <linux/string.h>
  19#include <linux/socket.h>
  20#include <linux/sockios.h>
  21#include <linux/errno.h>
  22#include <linux/in.h>
  23#include <linux/inet.h>
  24#include <linux/inetdevice.h>
  25#include <linux/netdevice.h>
  26#include <linux/if_arp.h>
  27#include <linux/proc_fs.h>
  28#include <linux/skbuff.h>
  29#include <linux/init.h>
  30#include <linux/slab.h>
  31#include <linux/netlink.h>
  32
  33#include <net/arp.h>
  34#include <net/ip.h>
  35#include <net/protocol.h>
  36#include <net/route.h>
  37#include <net/tcp.h>
  38#include <net/sock.h>
  39#include <net/ip_fib.h>
  40#include <net/ip6_fib.h>
  41#include <net/nexthop.h>
  42#include <net/netlink.h>
  43#include <net/rtnh.h>
  44#include <net/lwtunnel.h>
  45#include <net/fib_notifier.h>
  46#include <net/addrconf.h>
  47
  48#include "fib_lookup.h"
  49
  50static DEFINE_SPINLOCK(fib_info_lock);
  51static struct hlist_head *fib_info_hash;
  52static struct hlist_head *fib_info_laddrhash;
  53static unsigned int fib_info_hash_size;
  54static unsigned int fib_info_cnt;
  55
  56#define DEVINDEX_HASHBITS 8
  57#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
  58static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
  59
  60/* for_nexthops and change_nexthops only used when nexthop object
  61 * is not set in a fib_info. The logic within can reference fib_nh.
  62 */
  63#ifdef CONFIG_IP_ROUTE_MULTIPATH
  64
  65#define for_nexthops(fi) {						\
  66	int nhsel; const struct fib_nh *nh;				\
  67	for (nhsel = 0, nh = (fi)->fib_nh;				\
  68	     nhsel < fib_info_num_path((fi));				\
  69	     nh++, nhsel++)
  70
  71#define change_nexthops(fi) {						\
  72	int nhsel; struct fib_nh *nexthop_nh;				\
  73	for (nhsel = 0,	nexthop_nh = (struct fib_nh *)((fi)->fib_nh);	\
  74	     nhsel < fib_info_num_path((fi));				\
  75	     nexthop_nh++, nhsel++)
  76
  77#else /* CONFIG_IP_ROUTE_MULTIPATH */
  78
  79/* Hope, that gcc will optimize it to get rid of dummy loop */
  80
  81#define for_nexthops(fi) {						\
  82	int nhsel; const struct fib_nh *nh = (fi)->fib_nh;		\
  83	for (nhsel = 0; nhsel < 1; nhsel++)
  84
  85#define change_nexthops(fi) {						\
  86	int nhsel;							\
  87	struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);	\
  88	for (nhsel = 0; nhsel < 1; nhsel++)
  89
  90#endif /* CONFIG_IP_ROUTE_MULTIPATH */
  91
  92#define endfor_nexthops(fi) }
  93
  94
  95const struct fib_prop fib_props[RTN_MAX + 1] = {
  96	[RTN_UNSPEC] = {
  97		.error	= 0,
  98		.scope	= RT_SCOPE_NOWHERE,
  99	},
 100	[RTN_UNICAST] = {
 101		.error	= 0,
 102		.scope	= RT_SCOPE_UNIVERSE,
 103	},
 104	[RTN_LOCAL] = {
 105		.error	= 0,
 106		.scope	= RT_SCOPE_HOST,
 107	},
 108	[RTN_BROADCAST] = {
 109		.error	= 0,
 110		.scope	= RT_SCOPE_LINK,
 111	},
 112	[RTN_ANYCAST] = {
 113		.error	= 0,
 114		.scope	= RT_SCOPE_LINK,
 115	},
 116	[RTN_MULTICAST] = {
 117		.error	= 0,
 118		.scope	= RT_SCOPE_UNIVERSE,
 119	},
 120	[RTN_BLACKHOLE] = {
 121		.error	= -EINVAL,
 122		.scope	= RT_SCOPE_UNIVERSE,
 123	},
 124	[RTN_UNREACHABLE] = {
 125		.error	= -EHOSTUNREACH,
 126		.scope	= RT_SCOPE_UNIVERSE,
 127	},
 128	[RTN_PROHIBIT] = {
 129		.error	= -EACCES,
 130		.scope	= RT_SCOPE_UNIVERSE,
 131	},
 132	[RTN_THROW] = {
 133		.error	= -EAGAIN,
 134		.scope	= RT_SCOPE_UNIVERSE,
 135	},
 136	[RTN_NAT] = {
 137		.error	= -EINVAL,
 138		.scope	= RT_SCOPE_NOWHERE,
 139	},
 140	[RTN_XRESOLVE] = {
 141		.error	= -EINVAL,
 142		.scope	= RT_SCOPE_NOWHERE,
 143	},
 144};
 145
 146static void rt_fibinfo_free(struct rtable __rcu **rtp)
 147{
 148	struct rtable *rt = rcu_dereference_protected(*rtp, 1);
 149
 150	if (!rt)
 151		return;
 152
 153	/* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
 154	 * because we waited an RCU grace period before calling
 155	 * free_fib_info_rcu()
 156	 */
 157
 158	dst_dev_put(&rt->dst);
 159	dst_release_immediate(&rt->dst);
 160}
 161
 162static void free_nh_exceptions(struct fib_nh_common *nhc)
 163{
 164	struct fnhe_hash_bucket *hash;
 165	int i;
 166
 167	hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
 168	if (!hash)
 169		return;
 170	for (i = 0; i < FNHE_HASH_SIZE; i++) {
 171		struct fib_nh_exception *fnhe;
 172
 173		fnhe = rcu_dereference_protected(hash[i].chain, 1);
 174		while (fnhe) {
 175			struct fib_nh_exception *next;
 176
 177			next = rcu_dereference_protected(fnhe->fnhe_next, 1);
 178
 179			rt_fibinfo_free(&fnhe->fnhe_rth_input);
 180			rt_fibinfo_free(&fnhe->fnhe_rth_output);
 181
 182			kfree(fnhe);
 183
 184			fnhe = next;
 185		}
 186	}
 187	kfree(hash);
 188}
 189
 190static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 191{
 192	int cpu;
 193
 194	if (!rtp)
 195		return;
 196
 197	for_each_possible_cpu(cpu) {
 198		struct rtable *rt;
 199
 200		rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
 201		if (rt) {
 202			dst_dev_put(&rt->dst);
 203			dst_release_immediate(&rt->dst);
 204		}
 205	}
 206	free_percpu(rtp);
 207}
 208
 209void fib_nh_common_release(struct fib_nh_common *nhc)
 210{
 211	if (nhc->nhc_dev)
 212		dev_put(nhc->nhc_dev);
 213
 214	lwtstate_put(nhc->nhc_lwtstate);
 215	rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 216	rt_fibinfo_free(&nhc->nhc_rth_input);
 217	free_nh_exceptions(nhc);
 218}
 219EXPORT_SYMBOL_GPL(fib_nh_common_release);
 220
 221void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 222{
 223#ifdef CONFIG_IP_ROUTE_CLASSID
 224	if (fib_nh->nh_tclassid)
 225		net->ipv4.fib_num_tclassid_users--;
 226#endif
 227	fib_nh_common_release(&fib_nh->nh_common);
 228}
 229
 230/* Release a nexthop info record */
 231static void free_fib_info_rcu(struct rcu_head *head)
 232{
 233	struct fib_info *fi = container_of(head, struct fib_info, rcu);
 234
 235	if (fi->nh) {
 236		nexthop_put(fi->nh);
 237	} else {
 238		change_nexthops(fi) {
 239			fib_nh_release(fi->fib_net, nexthop_nh);
 240		} endfor_nexthops(fi);
 241	}
 242
 243	ip_fib_metrics_put(fi->fib_metrics);
 244
 245	kfree(fi);
 246}
 247
 248void free_fib_info(struct fib_info *fi)
 249{
 250	if (fi->fib_dead == 0) {
 251		pr_warn("Freeing alive fib_info %p\n", fi);
 252		return;
 253	}
 254	fib_info_cnt--;
 255
 256	call_rcu(&fi->rcu, free_fib_info_rcu);
 257}
 258EXPORT_SYMBOL_GPL(free_fib_info);
 259
 260void fib_release_info(struct fib_info *fi)
 261{
 262	spin_lock_bh(&fib_info_lock);
 263	if (fi && --fi->fib_treeref == 0) {
 264		hlist_del(&fi->fib_hash);
 265		if (fi->fib_prefsrc)
 266			hlist_del(&fi->fib_lhash);
 267		if (fi->nh) {
 268			list_del(&fi->nh_list);
 269		} else {
 270			change_nexthops(fi) {
 271				if (!nexthop_nh->fib_nh_dev)
 272					continue;
 273				hlist_del(&nexthop_nh->nh_hash);
 274			} endfor_nexthops(fi)
 275		}
 276		fi->fib_dead = 1;
 277		fib_info_put(fi);
 278	}
 279	spin_unlock_bh(&fib_info_lock);
 280}
 281
 282static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
 283{
 284	const struct fib_nh *onh;
 285
 286	if (fi->nh || ofi->nh)
 287		return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
 288
 289	if (ofi->fib_nhs == 0)
 290		return 0;
 291
 292	for_nexthops(fi) {
 293		onh = fib_info_nh(ofi, nhsel);
 294
 295		if (nh->fib_nh_oif != onh->fib_nh_oif ||
 296		    nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
 297		    nh->fib_nh_scope != onh->fib_nh_scope ||
 298#ifdef CONFIG_IP_ROUTE_MULTIPATH
 299		    nh->fib_nh_weight != onh->fib_nh_weight ||
 300#endif
 301#ifdef CONFIG_IP_ROUTE_CLASSID
 302		    nh->nh_tclassid != onh->nh_tclassid ||
 303#endif
 304		    lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
 305		    ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
 306			return -1;
 307
 308		if (nh->fib_nh_gw_family == AF_INET &&
 309		    nh->fib_nh_gw4 != onh->fib_nh_gw4)
 310			return -1;
 311
 312		if (nh->fib_nh_gw_family == AF_INET6 &&
 313		    ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
 314			return -1;
 315	} endfor_nexthops(fi);
 316	return 0;
 317}
 318
 319static inline unsigned int fib_devindex_hashfn(unsigned int val)
 320{
 321	unsigned int mask = DEVINDEX_HASHSIZE - 1;
 322
 323	return (val ^
 324		(val >> DEVINDEX_HASHBITS) ^
 325		(val >> (DEVINDEX_HASHBITS * 2))) & mask;
 326}
 327
 328static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
 329				      u32 prefsrc, u32 priority)
 330{
 331	unsigned int val = init_val;
 332
 333	val ^= (protocol << 8) | scope;
 334	val ^= prefsrc;
 335	val ^= priority;
 336
 337	return val;
 338}
 339
 340static unsigned int fib_info_hashfn_result(unsigned int val)
 341{
 342	unsigned int mask = (fib_info_hash_size - 1);
 343
 344	return (val ^ (val >> 7) ^ (val >> 12)) & mask;
 345}
 346
 347static inline unsigned int fib_info_hashfn(struct fib_info *fi)
 348{
 349	unsigned int val;
 350
 351	val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
 352				fi->fib_scope, (__force u32)fi->fib_prefsrc,
 353				fi->fib_priority);
 354
 355	if (fi->nh) {
 356		val ^= fib_devindex_hashfn(fi->nh->id);
 357	} else {
 358		for_nexthops(fi) {
 359			val ^= fib_devindex_hashfn(nh->fib_nh_oif);
 360		} endfor_nexthops(fi)
 361	}
 362
 363	return fib_info_hashfn_result(val);
 364}
 365
 366/* no metrics, only nexthop id */
 367static struct fib_info *fib_find_info_nh(struct net *net,
 368					 const struct fib_config *cfg)
 369{
 370	struct hlist_head *head;
 371	struct fib_info *fi;
 372	unsigned int hash;
 373
 374	hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
 375				 cfg->fc_protocol, cfg->fc_scope,
 376				 (__force u32)cfg->fc_prefsrc,
 377				 cfg->fc_priority);
 378	hash = fib_info_hashfn_result(hash);
 379	head = &fib_info_hash[hash];
 380
 381	hlist_for_each_entry(fi, head, fib_hash) {
 382		if (!net_eq(fi->fib_net, net))
 383			continue;
 384		if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
 385			continue;
 386		if (cfg->fc_protocol == fi->fib_protocol &&
 387		    cfg->fc_scope == fi->fib_scope &&
 388		    cfg->fc_prefsrc == fi->fib_prefsrc &&
 389		    cfg->fc_priority == fi->fib_priority &&
 390		    cfg->fc_type == fi->fib_type &&
 391		    cfg->fc_table == fi->fib_tb_id &&
 392		    !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
 393			return fi;
 394	}
 395
 396	return NULL;
 397}
 398
 399static struct fib_info *fib_find_info(struct fib_info *nfi)
 400{
 401	struct hlist_head *head;
 402	struct fib_info *fi;
 403	unsigned int hash;
 404
 405	hash = fib_info_hashfn(nfi);
 406	head = &fib_info_hash[hash];
 407
 408	hlist_for_each_entry(fi, head, fib_hash) {
 409		if (!net_eq(fi->fib_net, nfi->fib_net))
 410			continue;
 411		if (fi->fib_nhs != nfi->fib_nhs)
 412			continue;
 413		if (nfi->fib_protocol == fi->fib_protocol &&
 414		    nfi->fib_scope == fi->fib_scope &&
 415		    nfi->fib_prefsrc == fi->fib_prefsrc &&
 416		    nfi->fib_priority == fi->fib_priority &&
 417		    nfi->fib_type == fi->fib_type &&
 418		    memcmp(nfi->fib_metrics, fi->fib_metrics,
 419			   sizeof(u32) * RTAX_MAX) == 0 &&
 420		    !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
 421		    nh_comp(fi, nfi) == 0)
 422			return fi;
 423	}
 424
 425	return NULL;
 426}
 427
 428/* Check, that the gateway is already configured.
 429 * Used only by redirect accept routine.
 430 */
 431int ip_fib_check_default(__be32 gw, struct net_device *dev)
 432{
 433	struct hlist_head *head;
 434	struct fib_nh *nh;
 435	unsigned int hash;
 436
 437	spin_lock(&fib_info_lock);
 438
 439	hash = fib_devindex_hashfn(dev->ifindex);
 440	head = &fib_info_devhash[hash];
 441	hlist_for_each_entry(nh, head, nh_hash) {
 442		if (nh->fib_nh_dev == dev &&
 443		    nh->fib_nh_gw4 == gw &&
 444		    !(nh->fib_nh_flags & RTNH_F_DEAD)) {
 445			spin_unlock(&fib_info_lock);
 446			return 0;
 447		}
 448	}
 449
 450	spin_unlock(&fib_info_lock);
 451
 452	return -1;
 453}
 454
 455static inline size_t fib_nlmsg_size(struct fib_info *fi)
 456{
 457	size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
 458			 + nla_total_size(4) /* RTA_TABLE */
 459			 + nla_total_size(4) /* RTA_DST */
 460			 + nla_total_size(4) /* RTA_PRIORITY */
 461			 + nla_total_size(4) /* RTA_PREFSRC */
 462			 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
 463	unsigned int nhs = fib_info_num_path(fi);
 464
 465	/* space for nested metrics */
 466	payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
 467
 468	if (fi->nh)
 469		payload += nla_total_size(4); /* RTA_NH_ID */
 470
 471	if (nhs) {
 472		size_t nh_encapsize = 0;
 473		/* Also handles the special case nhs == 1 */
 474
 475		/* each nexthop is packed in an attribute */
 476		size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
 477		unsigned int i;
 478
 479		/* may contain flow and gateway attribute */
 480		nhsize += 2 * nla_total_size(4);
 481
 482		/* grab encap info */
 483		for (i = 0; i < fib_info_num_path(fi); i++) {
 484			struct fib_nh_common *nhc = fib_info_nhc(fi, i);
 485
 486			if (nhc->nhc_lwtstate) {
 487				/* RTA_ENCAP_TYPE */
 488				nh_encapsize += lwtunnel_get_encap_size(
 489						nhc->nhc_lwtstate);
 490				/* RTA_ENCAP */
 491				nh_encapsize +=  nla_total_size(2);
 492			}
 493		}
 494
 495		/* all nexthops are packed in a nested attribute */
 496		payload += nla_total_size((nhs * nhsize) + nh_encapsize);
 497
 498	}
 499
 500	return payload;
 501}
 502
 503void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
 504	       int dst_len, u32 tb_id, const struct nl_info *info,
 505	       unsigned int nlm_flags)
 506{
 507	struct fib_rt_info fri;
 508	struct sk_buff *skb;
 509	u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
 510	int err = -ENOBUFS;
 511
 512	skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
 513	if (!skb)
 514		goto errout;
 515
 516	fri.fi = fa->fa_info;
 517	fri.tb_id = tb_id;
 518	fri.dst = key;
 519	fri.dst_len = dst_len;
 520	fri.tos = fa->fa_tos;
 521	fri.type = fa->fa_type;
 522	fri.offload = fa->offload;
 523	fri.trap = fa->trap;
 
 524	err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
 525	if (err < 0) {
 526		/* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 527		WARN_ON(err == -EMSGSIZE);
 528		kfree_skb(skb);
 529		goto errout;
 530	}
 531	rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 532		    info->nlh, GFP_KERNEL);
 533	return;
 534errout:
 535	if (err < 0)
 536		rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 537}
 538
 539static int fib_detect_death(struct fib_info *fi, int order,
 540			    struct fib_info **last_resort, int *last_idx,
 541			    int dflt)
 542{
 543	const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 544	struct neighbour *n;
 545	int state = NUD_NONE;
 546
 547	if (likely(nhc->nhc_gw_family == AF_INET))
 548		n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 549	else if (nhc->nhc_gw_family == AF_INET6)
 550		n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 551				 nhc->nhc_dev);
 552	else
 553		n = NULL;
 554
 555	if (n) {
 556		state = n->nud_state;
 557		neigh_release(n);
 558	} else {
 559		return 0;
 560	}
 561	if (state == NUD_REACHABLE)
 562		return 0;
 563	if ((state & NUD_VALID) && order != dflt)
 564		return 0;
 565	if ((state & NUD_VALID) ||
 566	    (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 567		*last_resort = fi;
 568		*last_idx = order;
 569	}
 570	return 1;
 571}
 572
 573int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 574		       struct nlattr *encap, u16 encap_type,
 575		       void *cfg, gfp_t gfp_flags,
 576		       struct netlink_ext_ack *extack)
 577{
 578	int err;
 579
 580	nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 581						    gfp_flags);
 582	if (!nhc->nhc_pcpu_rth_output)
 583		return -ENOMEM;
 584
 585	if (encap) {
 586		struct lwtunnel_state *lwtstate;
 587
 588		if (encap_type == LWTUNNEL_ENCAP_NONE) {
 589			NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 590			err = -EINVAL;
 591			goto lwt_failure;
 592		}
 593		err = lwtunnel_build_state(net, encap_type, encap,
 594					   nhc->nhc_family, cfg, &lwtstate,
 595					   extack);
 596		if (err)
 597			goto lwt_failure;
 598
 599		nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 600	}
 601
 602	return 0;
 603
 604lwt_failure:
 605	rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 606	nhc->nhc_pcpu_rth_output = NULL;
 607	return err;
 608}
 609EXPORT_SYMBOL_GPL(fib_nh_common_init);
 610
 611int fib_nh_init(struct net *net, struct fib_nh *nh,
 612		struct fib_config *cfg, int nh_weight,
 613		struct netlink_ext_ack *extack)
 614{
 615	int err;
 616
 617	nh->fib_nh_family = AF_INET;
 618
 619	err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
 620				 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 621	if (err)
 622		return err;
 623
 624	nh->fib_nh_oif = cfg->fc_oif;
 625	nh->fib_nh_gw_family = cfg->fc_gw_family;
 626	if (cfg->fc_gw_family == AF_INET)
 627		nh->fib_nh_gw4 = cfg->fc_gw4;
 628	else if (cfg->fc_gw_family == AF_INET6)
 629		nh->fib_nh_gw6 = cfg->fc_gw6;
 630
 631	nh->fib_nh_flags = cfg->fc_flags;
 632
 633#ifdef CONFIG_IP_ROUTE_CLASSID
 634	nh->nh_tclassid = cfg->fc_flow;
 635	if (nh->nh_tclassid)
 636		net->ipv4.fib_num_tclassid_users++;
 637#endif
 638#ifdef CONFIG_IP_ROUTE_MULTIPATH
 639	nh->fib_nh_weight = nh_weight;
 640#endif
 641	return 0;
 642}
 643
 644#ifdef CONFIG_IP_ROUTE_MULTIPATH
 645
 646static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 647			      struct netlink_ext_ack *extack)
 648{
 649	int nhs = 0;
 650
 651	while (rtnh_ok(rtnh, remaining)) {
 652		nhs++;
 653		rtnh = rtnh_next(rtnh, &remaining);
 654	}
 655
 656	/* leftover implies invalid nexthop configuration, discard it */
 657	if (remaining > 0) {
 658		NL_SET_ERR_MSG(extack,
 659			       "Invalid nexthop configuration - extra data after nexthops");
 660		nhs = 0;
 661	}
 662
 663	return nhs;
 664}
 665
 666/* only called when fib_nh is integrated into fib_info */
 667static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 668		       int remaining, struct fib_config *cfg,
 669		       struct netlink_ext_ack *extack)
 670{
 671	struct net *net = fi->fib_net;
 672	struct fib_config fib_cfg;
 673	struct fib_nh *nh;
 674	int ret;
 675
 676	change_nexthops(fi) {
 677		int attrlen;
 678
 679		memset(&fib_cfg, 0, sizeof(fib_cfg));
 680
 681		if (!rtnh_ok(rtnh, remaining)) {
 682			NL_SET_ERR_MSG(extack,
 683				       "Invalid nexthop configuration - extra data after nexthop");
 684			return -EINVAL;
 685		}
 686
 687		if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 688			NL_SET_ERR_MSG(extack,
 689				       "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 690			return -EINVAL;
 691		}
 692
 693		fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 694		fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 695
 696		attrlen = rtnh_attrlen(rtnh);
 697		if (attrlen > 0) {
 698			struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 699
 700			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 701			nlav = nla_find(attrs, attrlen, RTA_VIA);
 702			if (nla && nlav) {
 703				NL_SET_ERR_MSG(extack,
 704					       "Nexthop configuration can not contain both GATEWAY and VIA");
 705				return -EINVAL;
 706			}
 707			if (nla) {
 708				fib_cfg.fc_gw4 = nla_get_in_addr(nla);
 709				if (fib_cfg.fc_gw4)
 710					fib_cfg.fc_gw_family = AF_INET;
 711			} else if (nlav) {
 712				ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 713				if (ret)
 714					goto errout;
 715			}
 716
 717			nla = nla_find(attrs, attrlen, RTA_FLOW);
 718			if (nla)
 719				fib_cfg.fc_flow = nla_get_u32(nla);
 720
 721			fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 722			nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 723			if (nla)
 724				fib_cfg.fc_encap_type = nla_get_u16(nla);
 725		}
 726
 727		ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 728				  rtnh->rtnh_hops + 1, extack);
 729		if (ret)
 730			goto errout;
 731
 732		rtnh = rtnh_next(rtnh, &remaining);
 733	} endfor_nexthops(fi);
 734
 735	ret = -EINVAL;
 736	nh = fib_info_nh(fi, 0);
 737	if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 738		NL_SET_ERR_MSG(extack,
 739			       "Nexthop device index does not match RTA_OIF");
 740		goto errout;
 741	}
 742	if (cfg->fc_gw_family) {
 743		if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 744		    (cfg->fc_gw_family == AF_INET &&
 745		     nh->fib_nh_gw4 != cfg->fc_gw4) ||
 746		    (cfg->fc_gw_family == AF_INET6 &&
 747		     ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 748			NL_SET_ERR_MSG(extack,
 749				       "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 750			goto errout;
 751		}
 752	}
 753#ifdef CONFIG_IP_ROUTE_CLASSID
 754	if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 755		NL_SET_ERR_MSG(extack,
 756			       "Nexthop class id does not match RTA_FLOW");
 757		goto errout;
 758	}
 759#endif
 760	ret = 0;
 761errout:
 762	return ret;
 763}
 764
 765/* only called when fib_nh is integrated into fib_info */
 766static void fib_rebalance(struct fib_info *fi)
 767{
 768	int total;
 769	int w;
 770
 771	if (fib_info_num_path(fi) < 2)
 772		return;
 773
 774	total = 0;
 775	for_nexthops(fi) {
 776		if (nh->fib_nh_flags & RTNH_F_DEAD)
 777			continue;
 778
 779		if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 780		    nh->fib_nh_flags & RTNH_F_LINKDOWN)
 781			continue;
 782
 783		total += nh->fib_nh_weight;
 784	} endfor_nexthops(fi);
 785
 786	w = 0;
 787	change_nexthops(fi) {
 788		int upper_bound;
 789
 790		if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 791			upper_bound = -1;
 792		} else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 793			   nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 794			upper_bound = -1;
 795		} else {
 796			w += nexthop_nh->fib_nh_weight;
 797			upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 798							    total) - 1;
 799		}
 800
 801		atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 802	} endfor_nexthops(fi);
 803}
 804#else /* CONFIG_IP_ROUTE_MULTIPATH */
 805
 806static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 807		       int remaining, struct fib_config *cfg,
 808		       struct netlink_ext_ack *extack)
 809{
 810	NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 811
 812	return -EINVAL;
 813}
 814
 815#define fib_rebalance(fi) do { } while (0)
 816
 817#endif /* CONFIG_IP_ROUTE_MULTIPATH */
 818
 819static int fib_encap_match(struct net *net, u16 encap_type,
 820			   struct nlattr *encap,
 821			   const struct fib_nh *nh,
 822			   const struct fib_config *cfg,
 823			   struct netlink_ext_ack *extack)
 824{
 825	struct lwtunnel_state *lwtstate;
 826	int ret, result = 0;
 827
 828	if (encap_type == LWTUNNEL_ENCAP_NONE)
 829		return 0;
 830
 831	ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
 832				   cfg, &lwtstate, extack);
 833	if (!ret) {
 834		result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 835		lwtstate_free(lwtstate);
 836	}
 837
 838	return result;
 839}
 840
 841int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
 842		 struct netlink_ext_ack *extack)
 843{
 844#ifdef CONFIG_IP_ROUTE_MULTIPATH
 845	struct rtnexthop *rtnh;
 846	int remaining;
 847#endif
 848
 849	if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 850		return 1;
 851
 852	if (cfg->fc_nh_id) {
 853		if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 854			return 0;
 855		return 1;
 856	}
 857
 858	if (cfg->fc_oif || cfg->fc_gw_family) {
 859		struct fib_nh *nh = fib_info_nh(fi, 0);
 860
 861		if (cfg->fc_encap) {
 862			if (fib_encap_match(net, cfg->fc_encap_type,
 863					    cfg->fc_encap, nh, cfg, extack))
 864				return 1;
 865		}
 866#ifdef CONFIG_IP_ROUTE_CLASSID
 867		if (cfg->fc_flow &&
 868		    cfg->fc_flow != nh->nh_tclassid)
 869			return 1;
 870#endif
 871		if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 872		    (cfg->fc_gw_family &&
 873		     cfg->fc_gw_family != nh->fib_nh_gw_family))
 874			return 1;
 875
 876		if (cfg->fc_gw_family == AF_INET &&
 877		    cfg->fc_gw4 != nh->fib_nh_gw4)
 878			return 1;
 879
 880		if (cfg->fc_gw_family == AF_INET6 &&
 881		    ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 882			return 1;
 883
 884		return 0;
 885	}
 886
 887#ifdef CONFIG_IP_ROUTE_MULTIPATH
 888	if (!cfg->fc_mp)
 889		return 0;
 890
 891	rtnh = cfg->fc_mp;
 892	remaining = cfg->fc_mp_len;
 893
 894	for_nexthops(fi) {
 895		int attrlen;
 896
 897		if (!rtnh_ok(rtnh, remaining))
 898			return -EINVAL;
 899
 900		if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 901			return 1;
 902
 903		attrlen = rtnh_attrlen(rtnh);
 904		if (attrlen > 0) {
 905			struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 906
 907			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 908			nlav = nla_find(attrs, attrlen, RTA_VIA);
 909			if (nla && nlav) {
 910				NL_SET_ERR_MSG(extack,
 911					       "Nexthop configuration can not contain both GATEWAY and VIA");
 912				return -EINVAL;
 913			}
 914
 915			if (nla) {
 916				if (nh->fib_nh_gw_family != AF_INET ||
 917				    nla_get_in_addr(nla) != nh->fib_nh_gw4)
 918					return 1;
 919			} else if (nlav) {
 920				struct fib_config cfg2;
 921				int err;
 922
 923				err = fib_gw_from_via(&cfg2, nlav, extack);
 924				if (err)
 925					return err;
 926
 927				switch (nh->fib_nh_gw_family) {
 928				case AF_INET:
 929					if (cfg2.fc_gw_family != AF_INET ||
 930					    cfg2.fc_gw4 != nh->fib_nh_gw4)
 931						return 1;
 932					break;
 933				case AF_INET6:
 934					if (cfg2.fc_gw_family != AF_INET6 ||
 935					    ipv6_addr_cmp(&cfg2.fc_gw6,
 936							  &nh->fib_nh_gw6))
 937						return 1;
 938					break;
 939				}
 940			}
 941
 942#ifdef CONFIG_IP_ROUTE_CLASSID
 943			nla = nla_find(attrs, attrlen, RTA_FLOW);
 944			if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 945				return 1;
 946#endif
 947		}
 948
 949		rtnh = rtnh_next(rtnh, &remaining);
 950	} endfor_nexthops(fi);
 951#endif
 952	return 0;
 953}
 954
 955bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 956{
 957	struct nlattr *nla;
 958	int remaining;
 959
 960	if (!cfg->fc_mx)
 961		return true;
 962
 963	nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 964		int type = nla_type(nla);
 965		u32 fi_val, val;
 966
 967		if (!type)
 968			continue;
 969		if (type > RTAX_MAX)
 970			return false;
 971
 972		if (type == RTAX_CC_ALGO) {
 973			char tmp[TCP_CA_NAME_MAX];
 974			bool ecn_ca = false;
 975
 976			nla_strlcpy(tmp, nla, sizeof(tmp));
 977			val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 978		} else {
 979			if (nla_len(nla) != sizeof(u32))
 980				return false;
 981			val = nla_get_u32(nla);
 982		}
 983
 984		fi_val = fi->fib_metrics->metrics[type - 1];
 985		if (type == RTAX_FEATURES)
 986			fi_val &= ~DST_FEATURE_ECN_CA;
 987
 988		if (fi_val != val)
 989			return false;
 990	}
 991
 992	return true;
 993}
 994
 995static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
 996			      u32 table, struct netlink_ext_ack *extack)
 997{
 998	struct fib6_config cfg = {
 999		.fc_table = table,
1000		.fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1001		.fc_ifindex = nh->fib_nh_oif,
1002		.fc_gateway = nh->fib_nh_gw6,
1003	};
1004	struct fib6_nh fib6_nh = {};
1005	int err;
1006
1007	err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1008	if (!err) {
1009		nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1010		dev_hold(nh->fib_nh_dev);
1011		nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1012		nh->fib_nh_scope = RT_SCOPE_LINK;
1013
1014		ipv6_stub->fib6_nh_release(&fib6_nh);
1015	}
1016
1017	return err;
1018}
1019
1020/*
1021 * Picture
1022 * -------
1023 *
1024 * Semantics of nexthop is very messy by historical reasons.
1025 * We have to take into account, that:
1026 * a) gateway can be actually local interface address,
1027 *    so that gatewayed route is direct.
1028 * b) gateway must be on-link address, possibly
1029 *    described not by an ifaddr, but also by a direct route.
1030 * c) If both gateway and interface are specified, they should not
1031 *    contradict.
1032 * d) If we use tunnel routes, gateway could be not on-link.
1033 *
1034 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1035 * results in pretty ugly and hairy code with obscure logic.
1036 *
1037 * I chose to generalized it instead, so that the size
1038 * of code does not increase practically, but it becomes
1039 * much more general.
1040 * Every prefix is assigned a "scope" value: "host" is local address,
1041 * "link" is direct route,
1042 * [ ... "site" ... "interior" ... ]
1043 * and "universe" is true gateway route with global meaning.
1044 *
1045 * Every prefix refers to a set of "nexthop"s (gw, oif),
1046 * where gw must have narrower scope. This recursion stops
1047 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1048 * which means that gw is forced to be on link.
1049 *
1050 * Code is still hairy, but now it is apparently logically
1051 * consistent and very flexible. F.e. as by-product it allows
1052 * to co-exists in peace independent exterior and interior
1053 * routing processes.
1054 *
1055 * Normally it looks as following.
1056 *
1057 * {universe prefix}  -> (gw, oif) [scope link]
1058 *		  |
1059 *		  |-> {link prefix} -> (gw, oif) [scope local]
1060 *					|
1061 *					|-> {local prefix} (terminal node)
1062 */
1063static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1064			      u8 scope, struct netlink_ext_ack *extack)
1065{
1066	struct net_device *dev;
1067	struct fib_result res;
1068	int err = 0;
1069
1070	if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1071		unsigned int addr_type;
1072
1073		if (scope >= RT_SCOPE_LINK) {
1074			NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1075			return -EINVAL;
1076		}
1077		dev = __dev_get_by_index(net, nh->fib_nh_oif);
1078		if (!dev) {
1079			NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1080			return -ENODEV;
1081		}
1082		if (!(dev->flags & IFF_UP)) {
1083			NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1084			return -ENETDOWN;
1085		}
1086		addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1087		if (addr_type != RTN_UNICAST) {
1088			NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1089			return -EINVAL;
1090		}
1091		if (!netif_carrier_ok(dev))
1092			nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1093		nh->fib_nh_dev = dev;
1094		dev_hold(dev);
1095		nh->fib_nh_scope = RT_SCOPE_LINK;
1096		return 0;
1097	}
1098	rcu_read_lock();
1099	{
1100		struct fib_table *tbl = NULL;
1101		struct flowi4 fl4 = {
1102			.daddr = nh->fib_nh_gw4,
1103			.flowi4_scope = scope + 1,
1104			.flowi4_oif = nh->fib_nh_oif,
1105			.flowi4_iif = LOOPBACK_IFINDEX,
1106		};
1107
1108		/* It is not necessary, but requires a bit of thinking */
1109		if (fl4.flowi4_scope < RT_SCOPE_LINK)
1110			fl4.flowi4_scope = RT_SCOPE_LINK;
1111
1112		if (table && table != RT_TABLE_MAIN)
1113			tbl = fib_get_table(net, table);
1114
1115		if (tbl)
1116			err = fib_table_lookup(tbl, &fl4, &res,
1117					       FIB_LOOKUP_IGNORE_LINKSTATE |
1118					       FIB_LOOKUP_NOREF);
1119
1120		/* on error or if no table given do full lookup. This
1121		 * is needed for example when nexthops are in the local
1122		 * table rather than the given table
1123		 */
1124		if (!tbl || err) {
1125			err = fib_lookup(net, &fl4, &res,
1126					 FIB_LOOKUP_IGNORE_LINKSTATE);
1127		}
1128
1129		if (err) {
1130			NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1131			goto out;
1132		}
1133	}
1134
1135	err = -EINVAL;
1136	if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1137		NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1138		goto out;
1139	}
1140	nh->fib_nh_scope = res.scope;
1141	nh->fib_nh_oif = FIB_RES_OIF(res);
1142	nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1143	if (!dev) {
1144		NL_SET_ERR_MSG(extack,
1145			       "No egress device for nexthop gateway");
1146		goto out;
1147	}
1148	dev_hold(dev);
1149	if (!netif_carrier_ok(dev))
1150		nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1151	err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1152out:
1153	rcu_read_unlock();
1154	return err;
1155}
1156
1157static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1158			      struct netlink_ext_ack *extack)
1159{
1160	struct in_device *in_dev;
1161	int err;
1162
1163	if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1164		NL_SET_ERR_MSG(extack,
1165			       "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1166		return -EINVAL;
1167	}
1168
1169	rcu_read_lock();
1170
1171	err = -ENODEV;
1172	in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1173	if (!in_dev)
1174		goto out;
1175	err = -ENETDOWN;
1176	if (!(in_dev->dev->flags & IFF_UP)) {
1177		NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1178		goto out;
1179	}
1180
1181	nh->fib_nh_dev = in_dev->dev;
1182	dev_hold(nh->fib_nh_dev);
1183	nh->fib_nh_scope = RT_SCOPE_HOST;
1184	if (!netif_carrier_ok(nh->fib_nh_dev))
1185		nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1186	err = 0;
1187out:
1188	rcu_read_unlock();
1189	return err;
1190}
1191
1192int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1193		 struct netlink_ext_ack *extack)
1194{
1195	int err;
1196
1197	if (nh->fib_nh_gw_family == AF_INET)
1198		err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1199	else if (nh->fib_nh_gw_family == AF_INET6)
1200		err = fib_check_nh_v6_gw(net, nh, table, extack);
1201	else
1202		err = fib_check_nh_nongw(net, nh, extack);
1203
1204	return err;
1205}
1206
1207static inline unsigned int fib_laddr_hashfn(__be32 val)
1208{
1209	unsigned int mask = (fib_info_hash_size - 1);
1210
1211	return ((__force u32)val ^
1212		((__force u32)val >> 7) ^
1213		((__force u32)val >> 14)) & mask;
1214}
1215
1216static struct hlist_head *fib_info_hash_alloc(int bytes)
1217{
1218	if (bytes <= PAGE_SIZE)
1219		return kzalloc(bytes, GFP_KERNEL);
1220	else
1221		return (struct hlist_head *)
1222			__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1223					 get_order(bytes));
1224}
1225
1226static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1227{
1228	if (!hash)
1229		return;
1230
1231	if (bytes <= PAGE_SIZE)
1232		kfree(hash);
1233	else
1234		free_pages((unsigned long) hash, get_order(bytes));
1235}
1236
1237static void fib_info_hash_move(struct hlist_head *new_info_hash,
1238			       struct hlist_head *new_laddrhash,
1239			       unsigned int new_size)
1240{
1241	struct hlist_head *old_info_hash, *old_laddrhash;
1242	unsigned int old_size = fib_info_hash_size;
1243	unsigned int i, bytes;
1244
1245	spin_lock_bh(&fib_info_lock);
1246	old_info_hash = fib_info_hash;
1247	old_laddrhash = fib_info_laddrhash;
1248	fib_info_hash_size = new_size;
1249
1250	for (i = 0; i < old_size; i++) {
1251		struct hlist_head *head = &fib_info_hash[i];
1252		struct hlist_node *n;
1253		struct fib_info *fi;
1254
1255		hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1256			struct hlist_head *dest;
1257			unsigned int new_hash;
1258
1259			new_hash = fib_info_hashfn(fi);
1260			dest = &new_info_hash[new_hash];
1261			hlist_add_head(&fi->fib_hash, dest);
1262		}
1263	}
1264	fib_info_hash = new_info_hash;
1265
1266	for (i = 0; i < old_size; i++) {
1267		struct hlist_head *lhead = &fib_info_laddrhash[i];
1268		struct hlist_node *n;
1269		struct fib_info *fi;
1270
1271		hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1272			struct hlist_head *ldest;
1273			unsigned int new_hash;
1274
1275			new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1276			ldest = &new_laddrhash[new_hash];
1277			hlist_add_head(&fi->fib_lhash, ldest);
1278		}
1279	}
1280	fib_info_laddrhash = new_laddrhash;
1281
1282	spin_unlock_bh(&fib_info_lock);
1283
1284	bytes = old_size * sizeof(struct hlist_head *);
1285	fib_info_hash_free(old_info_hash, bytes);
1286	fib_info_hash_free(old_laddrhash, bytes);
1287}
1288
1289__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1290				 unsigned char scope)
1291{
1292	struct fib_nh *nh;
1293
1294	if (nhc->nhc_family != AF_INET)
1295		return inet_select_addr(nhc->nhc_dev, 0, scope);
1296
1297	nh = container_of(nhc, struct fib_nh, nh_common);
1298	nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1299	nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1300
1301	return nh->nh_saddr;
1302}
1303
1304__be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1305{
1306	struct fib_nh_common *nhc = res->nhc;
1307
1308	if (res->fi->fib_prefsrc)
1309		return res->fi->fib_prefsrc;
1310
1311	if (nhc->nhc_family == AF_INET) {
1312		struct fib_nh *nh;
1313
1314		nh = container_of(nhc, struct fib_nh, nh_common);
1315		if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1316			return nh->nh_saddr;
1317	}
1318
1319	return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1320}
1321
1322static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1323{
1324	if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1325	    fib_prefsrc != cfg->fc_dst) {
1326		u32 tb_id = cfg->fc_table;
1327		int rc;
1328
1329		if (tb_id == RT_TABLE_MAIN)
1330			tb_id = RT_TABLE_LOCAL;
1331
1332		rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1333					  fib_prefsrc, tb_id);
1334
1335		if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1336			rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1337						  fib_prefsrc, RT_TABLE_LOCAL);
1338		}
1339
1340		if (rc != RTN_LOCAL)
1341			return false;
1342	}
1343	return true;
1344}
1345
1346struct fib_info *fib_create_info(struct fib_config *cfg,
1347				 struct netlink_ext_ack *extack)
1348{
1349	int err;
1350	struct fib_info *fi = NULL;
1351	struct nexthop *nh = NULL;
1352	struct fib_info *ofi;
1353	int nhs = 1;
1354	struct net *net = cfg->fc_nlinfo.nl_net;
1355
1356	if (cfg->fc_type > RTN_MAX)
1357		goto err_inval;
1358
1359	/* Fast check to catch the most weird cases */
1360	if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1361		NL_SET_ERR_MSG(extack, "Invalid scope");
1362		goto err_inval;
1363	}
1364
1365	if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1366		NL_SET_ERR_MSG(extack,
1367			       "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1368		goto err_inval;
1369	}
1370
1371	if (cfg->fc_nh_id) {
1372		if (!cfg->fc_mx) {
1373			fi = fib_find_info_nh(net, cfg);
1374			if (fi) {
1375				fi->fib_treeref++;
1376				return fi;
1377			}
1378		}
1379
1380		nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1381		if (!nh) {
1382			NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1383			goto err_inval;
1384		}
1385		nhs = 0;
1386	}
1387
1388#ifdef CONFIG_IP_ROUTE_MULTIPATH
1389	if (cfg->fc_mp) {
1390		nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1391		if (nhs == 0)
1392			goto err_inval;
1393	}
1394#endif
1395
1396	err = -ENOBUFS;
1397	if (fib_info_cnt >= fib_info_hash_size) {
1398		unsigned int new_size = fib_info_hash_size << 1;
1399		struct hlist_head *new_info_hash;
1400		struct hlist_head *new_laddrhash;
1401		unsigned int bytes;
1402
1403		if (!new_size)
1404			new_size = 16;
1405		bytes = new_size * sizeof(struct hlist_head *);
1406		new_info_hash = fib_info_hash_alloc(bytes);
1407		new_laddrhash = fib_info_hash_alloc(bytes);
1408		if (!new_info_hash || !new_laddrhash) {
1409			fib_info_hash_free(new_info_hash, bytes);
1410			fib_info_hash_free(new_laddrhash, bytes);
1411		} else
1412			fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1413
1414		if (!fib_info_hash_size)
1415			goto failure;
1416	}
1417
1418	fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1419	if (!fi)
1420		goto failure;
1421	fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1422					      cfg->fc_mx_len, extack);
1423	if (IS_ERR(fi->fib_metrics)) {
1424		err = PTR_ERR(fi->fib_metrics);
1425		kfree(fi);
1426		return ERR_PTR(err);
1427	}
1428
1429	fib_info_cnt++;
1430	fi->fib_net = net;
1431	fi->fib_protocol = cfg->fc_protocol;
1432	fi->fib_scope = cfg->fc_scope;
1433	fi->fib_flags = cfg->fc_flags;
1434	fi->fib_priority = cfg->fc_priority;
1435	fi->fib_prefsrc = cfg->fc_prefsrc;
1436	fi->fib_type = cfg->fc_type;
1437	fi->fib_tb_id = cfg->fc_table;
1438
1439	fi->fib_nhs = nhs;
1440	if (nh) {
1441		if (!nexthop_get(nh)) {
1442			NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1443			err = -EINVAL;
1444		} else {
1445			err = 0;
1446			fi->nh = nh;
1447		}
1448	} else {
1449		change_nexthops(fi) {
1450			nexthop_nh->nh_parent = fi;
1451		} endfor_nexthops(fi)
1452
1453		if (cfg->fc_mp)
1454			err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1455					  extack);
1456		else
1457			err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1458	}
1459
1460	if (err != 0)
1461		goto failure;
1462
1463	if (fib_props[cfg->fc_type].error) {
1464		if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1465			NL_SET_ERR_MSG(extack,
1466				       "Gateway, device and multipath can not be specified for this route type");
1467			goto err_inval;
1468		}
1469		goto link_it;
1470	} else {
1471		switch (cfg->fc_type) {
1472		case RTN_UNICAST:
1473		case RTN_LOCAL:
1474		case RTN_BROADCAST:
1475		case RTN_ANYCAST:
1476		case RTN_MULTICAST:
1477			break;
1478		default:
1479			NL_SET_ERR_MSG(extack, "Invalid route type");
1480			goto err_inval;
1481		}
1482	}
1483
1484	if (cfg->fc_scope > RT_SCOPE_HOST) {
1485		NL_SET_ERR_MSG(extack, "Invalid scope");
1486		goto err_inval;
1487	}
1488
1489	if (fi->nh) {
1490		err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1491		if (err)
1492			goto failure;
1493	} else if (cfg->fc_scope == RT_SCOPE_HOST) {
1494		struct fib_nh *nh = fi->fib_nh;
1495
1496		/* Local address is added. */
1497		if (nhs != 1) {
1498			NL_SET_ERR_MSG(extack,
1499				       "Route with host scope can not have multiple nexthops");
1500			goto err_inval;
1501		}
1502		if (nh->fib_nh_gw_family) {
1503			NL_SET_ERR_MSG(extack,
1504				       "Route with host scope can not have a gateway");
1505			goto err_inval;
1506		}
1507		nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1508		nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1509		err = -ENODEV;
1510		if (!nh->fib_nh_dev)
1511			goto failure;
1512	} else {
1513		int linkdown = 0;
1514
1515		change_nexthops(fi) {
1516			err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1517					   cfg->fc_table, cfg->fc_scope,
1518					   extack);
1519			if (err != 0)
1520				goto failure;
1521			if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1522				linkdown++;
1523		} endfor_nexthops(fi)
1524		if (linkdown == fi->fib_nhs)
1525			fi->fib_flags |= RTNH_F_LINKDOWN;
1526	}
1527
1528	if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1529		NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1530		goto err_inval;
1531	}
1532
1533	if (!fi->nh) {
1534		change_nexthops(fi) {
1535			fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1536						  fi->fib_scope);
1537			if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1538				fi->fib_nh_is_v6 = true;
1539		} endfor_nexthops(fi)
1540
1541		fib_rebalance(fi);
1542	}
1543
1544link_it:
1545	ofi = fib_find_info(fi);
1546	if (ofi) {
1547		fi->fib_dead = 1;
1548		free_fib_info(fi);
1549		ofi->fib_treeref++;
1550		return ofi;
1551	}
1552
1553	fi->fib_treeref++;
1554	refcount_set(&fi->fib_clntref, 1);
1555	spin_lock_bh(&fib_info_lock);
1556	hlist_add_head(&fi->fib_hash,
1557		       &fib_info_hash[fib_info_hashfn(fi)]);
1558	if (fi->fib_prefsrc) {
1559		struct hlist_head *head;
1560
1561		head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1562		hlist_add_head(&fi->fib_lhash, head);
1563	}
1564	if (fi->nh) {
1565		list_add(&fi->nh_list, &nh->fi_list);
1566	} else {
1567		change_nexthops(fi) {
1568			struct hlist_head *head;
1569			unsigned int hash;
1570
1571			if (!nexthop_nh->fib_nh_dev)
1572				continue;
1573			hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1574			head = &fib_info_devhash[hash];
1575			hlist_add_head(&nexthop_nh->nh_hash, head);
1576		} endfor_nexthops(fi)
1577	}
1578	spin_unlock_bh(&fib_info_lock);
1579	return fi;
1580
1581err_inval:
1582	err = -EINVAL;
1583
1584failure:
1585	if (fi) {
1586		fi->fib_dead = 1;
1587		free_fib_info(fi);
1588	}
1589
1590	return ERR_PTR(err);
1591}
1592
1593int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1594		     u8 rt_family, unsigned char *flags, bool skip_oif)
1595{
1596	if (nhc->nhc_flags & RTNH_F_DEAD)
1597		*flags |= RTNH_F_DEAD;
1598
1599	if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1600		*flags |= RTNH_F_LINKDOWN;
1601
1602		rcu_read_lock();
1603		switch (nhc->nhc_family) {
1604		case AF_INET:
1605			if (ip_ignore_linkdown(nhc->nhc_dev))
1606				*flags |= RTNH_F_DEAD;
1607			break;
1608		case AF_INET6:
1609			if (ip6_ignore_linkdown(nhc->nhc_dev))
1610				*flags |= RTNH_F_DEAD;
1611			break;
1612		}
1613		rcu_read_unlock();
1614	}
1615
1616	switch (nhc->nhc_gw_family) {
1617	case AF_INET:
1618		if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1619			goto nla_put_failure;
1620		break;
1621	case AF_INET6:
1622		/* if gateway family does not match nexthop family
1623		 * gateway is encoded as RTA_VIA
1624		 */
1625		if (rt_family != nhc->nhc_gw_family) {
1626			int alen = sizeof(struct in6_addr);
1627			struct nlattr *nla;
1628			struct rtvia *via;
1629
1630			nla = nla_reserve(skb, RTA_VIA, alen + 2);
1631			if (!nla)
1632				goto nla_put_failure;
1633
1634			via = nla_data(nla);
1635			via->rtvia_family = AF_INET6;
1636			memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1637		} else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1638					    &nhc->nhc_gw.ipv6) < 0) {
1639			goto nla_put_failure;
1640		}
1641		break;
1642	}
1643
1644	*flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1645	if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1646		*flags |= RTNH_F_OFFLOAD;
1647
1648	if (!skip_oif && nhc->nhc_dev &&
1649	    nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1650		goto nla_put_failure;
1651
1652	if (nhc->nhc_lwtstate &&
1653	    lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1654				RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1655		goto nla_put_failure;
1656
1657	return 0;
1658
1659nla_put_failure:
1660	return -EMSGSIZE;
1661}
1662EXPORT_SYMBOL_GPL(fib_nexthop_info);
1663
1664#if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1665int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1666		    int nh_weight, u8 rt_family)
1667{
1668	const struct net_device *dev = nhc->nhc_dev;
1669	struct rtnexthop *rtnh;
1670	unsigned char flags = 0;
1671
1672	rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1673	if (!rtnh)
1674		goto nla_put_failure;
1675
1676	rtnh->rtnh_hops = nh_weight - 1;
1677	rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1678
1679	if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1680		goto nla_put_failure;
1681
1682	rtnh->rtnh_flags = flags;
1683
 
 
 
1684	/* length of rtnetlink header + attributes */
1685	rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1686
1687	return 0;
1688
1689nla_put_failure:
1690	return -EMSGSIZE;
1691}
1692EXPORT_SYMBOL_GPL(fib_add_nexthop);
1693#endif
1694
1695#ifdef CONFIG_IP_ROUTE_MULTIPATH
1696static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1697{
1698	struct nlattr *mp;
1699
1700	mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1701	if (!mp)
1702		goto nla_put_failure;
1703
1704	if (unlikely(fi->nh)) {
1705		if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1706			goto nla_put_failure;
1707		goto mp_end;
1708	}
1709
1710	for_nexthops(fi) {
1711		if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1712				    AF_INET) < 0)
1713			goto nla_put_failure;
1714#ifdef CONFIG_IP_ROUTE_CLASSID
1715		if (nh->nh_tclassid &&
1716		    nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1717			goto nla_put_failure;
1718#endif
 
 
 
1719	} endfor_nexthops(fi);
1720
1721mp_end:
1722	nla_nest_end(skb, mp);
1723
1724	return 0;
1725
1726nla_put_failure:
1727	return -EMSGSIZE;
1728}
1729#else
1730static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1731{
1732	return 0;
1733}
1734#endif
1735
1736int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1737		  struct fib_rt_info *fri, unsigned int flags)
1738{
1739	unsigned int nhs = fib_info_num_path(fri->fi);
1740	struct fib_info *fi = fri->fi;
1741	u32 tb_id = fri->tb_id;
1742	struct nlmsghdr *nlh;
1743	struct rtmsg *rtm;
1744
1745	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1746	if (!nlh)
1747		return -EMSGSIZE;
1748
1749	rtm = nlmsg_data(nlh);
1750	rtm->rtm_family = AF_INET;
1751	rtm->rtm_dst_len = fri->dst_len;
1752	rtm->rtm_src_len = 0;
1753	rtm->rtm_tos = fri->tos;
1754	if (tb_id < 256)
1755		rtm->rtm_table = tb_id;
1756	else
1757		rtm->rtm_table = RT_TABLE_COMPAT;
1758	if (nla_put_u32(skb, RTA_TABLE, tb_id))
1759		goto nla_put_failure;
1760	rtm->rtm_type = fri->type;
1761	rtm->rtm_flags = fi->fib_flags;
1762	rtm->rtm_scope = fi->fib_scope;
1763	rtm->rtm_protocol = fi->fib_protocol;
1764
1765	if (rtm->rtm_dst_len &&
1766	    nla_put_in_addr(skb, RTA_DST, fri->dst))
1767		goto nla_put_failure;
1768	if (fi->fib_priority &&
1769	    nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1770		goto nla_put_failure;
1771	if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1772		goto nla_put_failure;
1773
1774	if (fi->fib_prefsrc &&
1775	    nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1776		goto nla_put_failure;
1777
1778	if (fi->nh) {
1779		if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1780			goto nla_put_failure;
1781		if (nexthop_is_blackhole(fi->nh))
1782			rtm->rtm_type = RTN_BLACKHOLE;
1783		if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1784			goto offload;
1785	}
1786
1787	if (nhs == 1) {
1788		const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1789		unsigned char flags = 0;
1790
1791		if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1792			goto nla_put_failure;
1793
1794		rtm->rtm_flags = flags;
1795#ifdef CONFIG_IP_ROUTE_CLASSID
1796		if (nhc->nhc_family == AF_INET) {
1797			struct fib_nh *nh;
1798
1799			nh = container_of(nhc, struct fib_nh, nh_common);
1800			if (nh->nh_tclassid &&
1801			    nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1802				goto nla_put_failure;
1803		}
1804#endif
1805	} else {
1806		if (fib_add_multipath(skb, fi) < 0)
1807			goto nla_put_failure;
1808	}
1809
1810offload:
1811	if (fri->offload)
1812		rtm->rtm_flags |= RTM_F_OFFLOAD;
1813	if (fri->trap)
1814		rtm->rtm_flags |= RTM_F_TRAP;
 
 
1815
1816	nlmsg_end(skb, nlh);
1817	return 0;
1818
1819nla_put_failure:
1820	nlmsg_cancel(skb, nlh);
1821	return -EMSGSIZE;
1822}
1823
1824/*
1825 * Update FIB if:
1826 * - local address disappeared -> we must delete all the entries
1827 *   referring to it.
1828 * - device went down -> we must shutdown all nexthops going via it.
1829 */
1830int fib_sync_down_addr(struct net_device *dev, __be32 local)
1831{
1832	int ret = 0;
1833	unsigned int hash = fib_laddr_hashfn(local);
1834	struct hlist_head *head = &fib_info_laddrhash[hash];
1835	int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1836	struct net *net = dev_net(dev);
1837	struct fib_info *fi;
1838
1839	if (!fib_info_laddrhash || local == 0)
1840		return 0;
1841
1842	hlist_for_each_entry(fi, head, fib_lhash) {
1843		if (!net_eq(fi->fib_net, net) ||
1844		    fi->fib_tb_id != tb_id)
1845			continue;
1846		if (fi->fib_prefsrc == local) {
1847			fi->fib_flags |= RTNH_F_DEAD;
1848			ret++;
1849		}
1850	}
1851	return ret;
1852}
1853
1854static int call_fib_nh_notifiers(struct fib_nh *nh,
1855				 enum fib_event_type event_type)
1856{
1857	bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1858	struct fib_nh_notifier_info info = {
1859		.fib_nh = nh,
1860	};
1861
1862	switch (event_type) {
1863	case FIB_EVENT_NH_ADD:
1864		if (nh->fib_nh_flags & RTNH_F_DEAD)
1865			break;
1866		if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1867			break;
1868		return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1869					   &info.info);
1870	case FIB_EVENT_NH_DEL:
1871		if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1872		    (nh->fib_nh_flags & RTNH_F_DEAD))
1873			return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1874						   event_type, &info.info);
 
1875	default:
1876		break;
1877	}
1878
1879	return NOTIFY_DONE;
1880}
1881
1882/* Update the PMTU of exceptions when:
1883 * - the new MTU of the first hop becomes smaller than the PMTU
1884 * - the old MTU was the same as the PMTU, and it limited discovery of
1885 *   larger MTUs on the path. With that limit raised, we can now
1886 *   discover larger MTUs
1887 * A special case is locked exceptions, for which the PMTU is smaller
1888 * than the minimal accepted PMTU:
1889 * - if the new MTU is greater than the PMTU, don't make any change
1890 * - otherwise, unlock and set PMTU
1891 */
1892void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1893{
1894	struct fnhe_hash_bucket *bucket;
1895	int i;
1896
1897	bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1898	if (!bucket)
1899		return;
1900
1901	for (i = 0; i < FNHE_HASH_SIZE; i++) {
1902		struct fib_nh_exception *fnhe;
1903
1904		for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1905		     fnhe;
1906		     fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1907			if (fnhe->fnhe_mtu_locked) {
1908				if (new <= fnhe->fnhe_pmtu) {
1909					fnhe->fnhe_pmtu = new;
1910					fnhe->fnhe_mtu_locked = false;
1911				}
1912			} else if (new < fnhe->fnhe_pmtu ||
1913				   orig == fnhe->fnhe_pmtu) {
1914				fnhe->fnhe_pmtu = new;
1915			}
1916		}
1917	}
1918}
1919
1920void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1921{
1922	unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1923	struct hlist_head *head = &fib_info_devhash[hash];
1924	struct fib_nh *nh;
1925
1926	hlist_for_each_entry(nh, head, nh_hash) {
1927		if (nh->fib_nh_dev == dev)
1928			fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1929	}
1930}
1931
1932/* Event              force Flags           Description
1933 * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1934 * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1935 * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1936 * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1937 *
1938 * only used when fib_nh is built into fib_info
1939 */
1940int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1941{
1942	int ret = 0;
1943	int scope = RT_SCOPE_NOWHERE;
1944	struct fib_info *prev_fi = NULL;
1945	unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1946	struct hlist_head *head = &fib_info_devhash[hash];
1947	struct fib_nh *nh;
1948
1949	if (force)
1950		scope = -1;
1951
1952	hlist_for_each_entry(nh, head, nh_hash) {
1953		struct fib_info *fi = nh->nh_parent;
1954		int dead;
1955
1956		BUG_ON(!fi->fib_nhs);
1957		if (nh->fib_nh_dev != dev || fi == prev_fi)
1958			continue;
1959		prev_fi = fi;
1960		dead = 0;
1961		change_nexthops(fi) {
1962			if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1963				dead++;
1964			else if (nexthop_nh->fib_nh_dev == dev &&
1965				 nexthop_nh->fib_nh_scope != scope) {
1966				switch (event) {
1967				case NETDEV_DOWN:
1968				case NETDEV_UNREGISTER:
1969					nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1970					fallthrough;
1971				case NETDEV_CHANGE:
1972					nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1973					break;
1974				}
1975				call_fib_nh_notifiers(nexthop_nh,
1976						      FIB_EVENT_NH_DEL);
1977				dead++;
1978			}
1979#ifdef CONFIG_IP_ROUTE_MULTIPATH
1980			if (event == NETDEV_UNREGISTER &&
1981			    nexthop_nh->fib_nh_dev == dev) {
1982				dead = fi->fib_nhs;
1983				break;
1984			}
1985#endif
1986		} endfor_nexthops(fi)
1987		if (dead == fi->fib_nhs) {
1988			switch (event) {
1989			case NETDEV_DOWN:
1990			case NETDEV_UNREGISTER:
1991				fi->fib_flags |= RTNH_F_DEAD;
1992				fallthrough;
1993			case NETDEV_CHANGE:
1994				fi->fib_flags |= RTNH_F_LINKDOWN;
1995				break;
1996			}
1997			ret++;
1998		}
1999
2000		fib_rebalance(fi);
2001	}
2002
2003	return ret;
2004}
2005
2006/* Must be invoked inside of an RCU protected region.  */
2007static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2008{
2009	struct fib_info *fi = NULL, *last_resort = NULL;
2010	struct hlist_head *fa_head = res->fa_head;
2011	struct fib_table *tb = res->table;
2012	u8 slen = 32 - res->prefixlen;
2013	int order = -1, last_idx = -1;
2014	struct fib_alias *fa, *fa1 = NULL;
2015	u32 last_prio = res->fi->fib_priority;
2016	u8 last_tos = 0;
2017
2018	hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2019		struct fib_info *next_fi = fa->fa_info;
2020		struct fib_nh_common *nhc;
2021
2022		if (fa->fa_slen != slen)
2023			continue;
2024		if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2025			continue;
2026		if (fa->tb_id != tb->tb_id)
2027			continue;
2028		if (next_fi->fib_priority > last_prio &&
2029		    fa->fa_tos == last_tos) {
2030			if (last_tos)
2031				continue;
2032			break;
2033		}
2034		if (next_fi->fib_flags & RTNH_F_DEAD)
2035			continue;
2036		last_tos = fa->fa_tos;
2037		last_prio = next_fi->fib_priority;
2038
2039		if (next_fi->fib_scope != res->scope ||
2040		    fa->fa_type != RTN_UNICAST)
2041			continue;
2042
2043		nhc = fib_info_nhc(next_fi, 0);
2044		if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2045			continue;
2046
2047		fib_alias_accessed(fa);
2048
2049		if (!fi) {
2050			if (next_fi != res->fi)
2051				break;
2052			fa1 = fa;
2053		} else if (!fib_detect_death(fi, order, &last_resort,
2054					     &last_idx, fa1->fa_default)) {
2055			fib_result_assign(res, fi);
2056			fa1->fa_default = order;
2057			goto out;
2058		}
2059		fi = next_fi;
2060		order++;
2061	}
2062
2063	if (order <= 0 || !fi) {
2064		if (fa1)
2065			fa1->fa_default = -1;
2066		goto out;
2067	}
2068
2069	if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2070			      fa1->fa_default)) {
2071		fib_result_assign(res, fi);
2072		fa1->fa_default = order;
2073		goto out;
2074	}
2075
2076	if (last_idx >= 0)
2077		fib_result_assign(res, last_resort);
2078	fa1->fa_default = last_idx;
2079out:
2080	return;
2081}
2082
2083/*
2084 * Dead device goes up. We wake up dead nexthops.
2085 * It takes sense only on multipath routes.
2086 *
2087 * only used when fib_nh is built into fib_info
2088 */
2089int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2090{
2091	struct fib_info *prev_fi;
2092	unsigned int hash;
2093	struct hlist_head *head;
2094	struct fib_nh *nh;
2095	int ret;
2096
2097	if (!(dev->flags & IFF_UP))
2098		return 0;
2099
2100	if (nh_flags & RTNH_F_DEAD) {
2101		unsigned int flags = dev_get_flags(dev);
2102
2103		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2104			nh_flags |= RTNH_F_LINKDOWN;
2105	}
2106
2107	prev_fi = NULL;
2108	hash = fib_devindex_hashfn(dev->ifindex);
2109	head = &fib_info_devhash[hash];
2110	ret = 0;
2111
2112	hlist_for_each_entry(nh, head, nh_hash) {
2113		struct fib_info *fi = nh->nh_parent;
2114		int alive;
2115
2116		BUG_ON(!fi->fib_nhs);
2117		if (nh->fib_nh_dev != dev || fi == prev_fi)
2118			continue;
2119
2120		prev_fi = fi;
2121		alive = 0;
2122		change_nexthops(fi) {
2123			if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2124				alive++;
2125				continue;
2126			}
2127			if (!nexthop_nh->fib_nh_dev ||
2128			    !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2129				continue;
2130			if (nexthop_nh->fib_nh_dev != dev ||
2131			    !__in_dev_get_rtnl(dev))
2132				continue;
2133			alive++;
2134			nexthop_nh->fib_nh_flags &= ~nh_flags;
2135			call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2136		} endfor_nexthops(fi)
2137
2138		if (alive > 0) {
2139			fi->fib_flags &= ~nh_flags;
2140			ret++;
2141		}
2142
2143		fib_rebalance(fi);
2144	}
2145
2146	return ret;
2147}
2148
2149#ifdef CONFIG_IP_ROUTE_MULTIPATH
2150static bool fib_good_nh(const struct fib_nh *nh)
2151{
2152	int state = NUD_REACHABLE;
2153
2154	if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2155		struct neighbour *n;
2156
2157		rcu_read_lock_bh();
2158
2159		if (likely(nh->fib_nh_gw_family == AF_INET))
2160			n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2161						   (__force u32)nh->fib_nh_gw4);
2162		else if (nh->fib_nh_gw_family == AF_INET6)
2163			n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2164							   &nh->fib_nh_gw6);
2165		else
2166			n = NULL;
2167		if (n)
2168			state = n->nud_state;
2169
2170		rcu_read_unlock_bh();
2171	}
2172
2173	return !!(state & NUD_VALID);
2174}
2175
2176void fib_select_multipath(struct fib_result *res, int hash)
2177{
2178	struct fib_info *fi = res->fi;
2179	struct net *net = fi->fib_net;
2180	bool first = false;
2181
2182	if (unlikely(res->fi->nh)) {
2183		nexthop_path_fib_result(res, hash);
2184		return;
2185	}
2186
2187	change_nexthops(fi) {
2188		if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2189			if (!fib_good_nh(nexthop_nh))
2190				continue;
2191			if (!first) {
2192				res->nh_sel = nhsel;
2193				res->nhc = &nexthop_nh->nh_common;
2194				first = true;
2195			}
2196		}
2197
2198		if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2199			continue;
2200
2201		res->nh_sel = nhsel;
2202		res->nhc = &nexthop_nh->nh_common;
2203		return;
2204	} endfor_nexthops(fi);
2205}
2206#endif
2207
2208void fib_select_path(struct net *net, struct fib_result *res,
2209		     struct flowi4 *fl4, const struct sk_buff *skb)
2210{
2211	if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2212		goto check_saddr;
2213
2214#ifdef CONFIG_IP_ROUTE_MULTIPATH
2215	if (fib_info_num_path(res->fi) > 1) {
2216		int h = fib_multipath_hash(net, fl4, skb, NULL);
2217
2218		fib_select_multipath(res, h);
2219	}
2220	else
2221#endif
2222	if (!res->prefixlen &&
2223	    res->table->tb_num_default > 1 &&
2224	    res->type == RTN_UNICAST)
2225		fib_select_default(fl4, res);
2226
2227check_saddr:
2228	if (!fl4->saddr)
2229		fl4->saddr = fib_result_prefsrc(net, res);
2230}