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
 455size_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	fri.offload_failed = fa->offload_failed;
 525	err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
 526	if (err < 0) {
 527		/* -EMSGSIZE implies BUG in fib_nlmsg_size() */
 528		WARN_ON(err == -EMSGSIZE);
 529		kfree_skb(skb);
 530		goto errout;
 531	}
 532	rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
 533		    info->nlh, GFP_KERNEL);
 534	return;
 535errout:
 536	if (err < 0)
 537		rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
 538}
 539
 540static int fib_detect_death(struct fib_info *fi, int order,
 541			    struct fib_info **last_resort, int *last_idx,
 542			    int dflt)
 543{
 544	const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
 545	struct neighbour *n;
 546	int state = NUD_NONE;
 547
 548	if (likely(nhc->nhc_gw_family == AF_INET))
 549		n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
 550	else if (nhc->nhc_gw_family == AF_INET6)
 551		n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
 552				 nhc->nhc_dev);
 553	else
 554		n = NULL;
 555
 556	if (n) {
 557		state = n->nud_state;
 558		neigh_release(n);
 559	} else {
 560		return 0;
 561	}
 562	if (state == NUD_REACHABLE)
 563		return 0;
 564	if ((state & NUD_VALID) && order != dflt)
 565		return 0;
 566	if ((state & NUD_VALID) ||
 567	    (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
 568		*last_resort = fi;
 569		*last_idx = order;
 570	}
 571	return 1;
 572}
 573
 574int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 575		       struct nlattr *encap, u16 encap_type,
 576		       void *cfg, gfp_t gfp_flags,
 577		       struct netlink_ext_ack *extack)
 578{
 579	int err;
 580
 581	nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
 582						    gfp_flags);
 583	if (!nhc->nhc_pcpu_rth_output)
 584		return -ENOMEM;
 585
 586	if (encap) {
 587		struct lwtunnel_state *lwtstate;
 588
 589		if (encap_type == LWTUNNEL_ENCAP_NONE) {
 590			NL_SET_ERR_MSG(extack, "LWT encap type not specified");
 591			err = -EINVAL;
 592			goto lwt_failure;
 593		}
 594		err = lwtunnel_build_state(net, encap_type, encap,
 595					   nhc->nhc_family, cfg, &lwtstate,
 596					   extack);
 597		if (err)
 598			goto lwt_failure;
 599
 600		nhc->nhc_lwtstate = lwtstate_get(lwtstate);
 601	}
 602
 603	return 0;
 604
 605lwt_failure:
 606	rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
 607	nhc->nhc_pcpu_rth_output = NULL;
 608	return err;
 609}
 610EXPORT_SYMBOL_GPL(fib_nh_common_init);
 611
 612int fib_nh_init(struct net *net, struct fib_nh *nh,
 613		struct fib_config *cfg, int nh_weight,
 614		struct netlink_ext_ack *extack)
 615{
 616	int err;
 617
 618	nh->fib_nh_family = AF_INET;
 619
 620	err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
 621				 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
 622	if (err)
 623		return err;
 624
 625	nh->fib_nh_oif = cfg->fc_oif;
 626	nh->fib_nh_gw_family = cfg->fc_gw_family;
 627	if (cfg->fc_gw_family == AF_INET)
 628		nh->fib_nh_gw4 = cfg->fc_gw4;
 629	else if (cfg->fc_gw_family == AF_INET6)
 630		nh->fib_nh_gw6 = cfg->fc_gw6;
 631
 632	nh->fib_nh_flags = cfg->fc_flags;
 633
 634#ifdef CONFIG_IP_ROUTE_CLASSID
 635	nh->nh_tclassid = cfg->fc_flow;
 636	if (nh->nh_tclassid)
 637		net->ipv4.fib_num_tclassid_users++;
 638#endif
 639#ifdef CONFIG_IP_ROUTE_MULTIPATH
 640	nh->fib_nh_weight = nh_weight;
 641#endif
 642	return 0;
 643}
 644
 645#ifdef CONFIG_IP_ROUTE_MULTIPATH
 646
 647static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
 648			      struct netlink_ext_ack *extack)
 649{
 650	int nhs = 0;
 651
 652	while (rtnh_ok(rtnh, remaining)) {
 653		nhs++;
 654		rtnh = rtnh_next(rtnh, &remaining);
 655	}
 656
 657	/* leftover implies invalid nexthop configuration, discard it */
 658	if (remaining > 0) {
 659		NL_SET_ERR_MSG(extack,
 660			       "Invalid nexthop configuration - extra data after nexthops");
 661		nhs = 0;
 662	}
 663
 664	return nhs;
 665}
 666
 667/* only called when fib_nh is integrated into fib_info */
 668static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 669		       int remaining, struct fib_config *cfg,
 670		       struct netlink_ext_ack *extack)
 671{
 672	struct net *net = fi->fib_net;
 673	struct fib_config fib_cfg;
 674	struct fib_nh *nh;
 675	int ret;
 676
 677	change_nexthops(fi) {
 678		int attrlen;
 679
 680		memset(&fib_cfg, 0, sizeof(fib_cfg));
 681
 682		if (!rtnh_ok(rtnh, remaining)) {
 683			NL_SET_ERR_MSG(extack,
 684				       "Invalid nexthop configuration - extra data after nexthop");
 685			return -EINVAL;
 686		}
 687
 688		if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
 689			NL_SET_ERR_MSG(extack,
 690				       "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 691			return -EINVAL;
 692		}
 693
 694		fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
 695		fib_cfg.fc_oif = rtnh->rtnh_ifindex;
 
 
 696
 697		attrlen = rtnh_attrlen(rtnh);
 698		if (attrlen > 0) {
 699			struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 700
 701			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 702			nlav = nla_find(attrs, attrlen, RTA_VIA);
 703			if (nla && nlav) {
 704				NL_SET_ERR_MSG(extack,
 705					       "Nexthop configuration can not contain both GATEWAY and VIA");
 706				return -EINVAL;
 707			}
 
 
 708			if (nla) {
 709				fib_cfg.fc_gw4 = nla_get_in_addr(nla);
 710				if (fib_cfg.fc_gw4)
 711					fib_cfg.fc_gw_family = AF_INET;
 712			} else if (nlav) {
 713				ret = fib_gw_from_via(&fib_cfg, nlav, extack);
 
 
 
 
 
 
 
 
 
 714				if (ret)
 715					goto errout;
 
 
 716			}
 717
 718			nla = nla_find(attrs, attrlen, RTA_FLOW);
 719			if (nla)
 720				fib_cfg.fc_flow = nla_get_u32(nla);
 721
 722			fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
 723			nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
 724			if (nla)
 725				fib_cfg.fc_encap_type = nla_get_u16(nla);
 726		}
 727
 728		ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
 729				  rtnh->rtnh_hops + 1, extack);
 730		if (ret)
 731			goto errout;
 732
 733		rtnh = rtnh_next(rtnh, &remaining);
 734	} endfor_nexthops(fi);
 735
 
 
 
 736	ret = -EINVAL;
 737	nh = fib_info_nh(fi, 0);
 738	if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
 739		NL_SET_ERR_MSG(extack,
 740			       "Nexthop device index does not match RTA_OIF");
 741		goto errout;
 742	}
 743	if (cfg->fc_gw_family) {
 744		if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
 745		    (cfg->fc_gw_family == AF_INET &&
 746		     nh->fib_nh_gw4 != cfg->fc_gw4) ||
 747		    (cfg->fc_gw_family == AF_INET6 &&
 748		     ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
 749			NL_SET_ERR_MSG(extack,
 750				       "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
 751			goto errout;
 752		}
 753	}
 754#ifdef CONFIG_IP_ROUTE_CLASSID
 755	if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
 756		NL_SET_ERR_MSG(extack,
 757			       "Nexthop class id does not match RTA_FLOW");
 758		goto errout;
 759	}
 760#endif
 761	ret = 0;
 762errout:
 763	return ret;
 764}
 765
 766/* only called when fib_nh is integrated into fib_info */
 767static void fib_rebalance(struct fib_info *fi)
 768{
 769	int total;
 770	int w;
 
 771
 772	if (fib_info_num_path(fi) < 2)
 773		return;
 774
 775	total = 0;
 776	for_nexthops(fi) {
 777		if (nh->fib_nh_flags & RTNH_F_DEAD)
 778			continue;
 779
 780		if (ip_ignore_linkdown(nh->fib_nh_dev) &&
 781		    nh->fib_nh_flags & RTNH_F_LINKDOWN)
 
 
 
 782			continue;
 783
 784		total += nh->fib_nh_weight;
 785	} endfor_nexthops(fi);
 786
 787	w = 0;
 788	change_nexthops(fi) {
 789		int upper_bound;
 790
 791		if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
 
 
 792			upper_bound = -1;
 793		} else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
 794			   nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
 
 795			upper_bound = -1;
 796		} else {
 797			w += nexthop_nh->fib_nh_weight;
 798			upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
 799							    total) - 1;
 800		}
 801
 802		atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
 803	} endfor_nexthops(fi);
 
 
 
 804}
 805#else /* CONFIG_IP_ROUTE_MULTIPATH */
 806
 807static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 808		       int remaining, struct fib_config *cfg,
 809		       struct netlink_ext_ack *extack)
 810{
 811	NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
 812
 813	return -EINVAL;
 814}
 815
 
 
 816#define fib_rebalance(fi) do { } while (0)
 
 817
 818#endif /* CONFIG_IP_ROUTE_MULTIPATH */
 819
 820static int fib_encap_match(struct net *net, u16 encap_type,
 821			   struct nlattr *encap,
 822			   const struct fib_nh *nh,
 823			   const struct fib_config *cfg,
 824			   struct netlink_ext_ack *extack)
 825{
 826	struct lwtunnel_state *lwtstate;
 
 827	int ret, result = 0;
 828
 829	if (encap_type == LWTUNNEL_ENCAP_NONE)
 830		return 0;
 831
 832	ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
 833				   cfg, &lwtstate, extack);
 
 
 834	if (!ret) {
 835		result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
 836		lwtstate_free(lwtstate);
 837	}
 838
 839	return result;
 840}
 841
 842int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
 843		 struct netlink_ext_ack *extack)
 844{
 
 845#ifdef CONFIG_IP_ROUTE_MULTIPATH
 846	struct rtnexthop *rtnh;
 847	int remaining;
 848#endif
 849
 850	if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
 851		return 1;
 852
 853	if (cfg->fc_nh_id) {
 854		if (fi->nh && cfg->fc_nh_id == fi->nh->id)
 855			return 0;
 856		return 1;
 857	}
 858
 859	if (cfg->fc_oif || cfg->fc_gw_family) {
 860		struct fib_nh *nh = fib_info_nh(fi, 0);
 861
 862		if (cfg->fc_encap) {
 863			if (fib_encap_match(net, cfg->fc_encap_type,
 864					    cfg->fc_encap, nh, cfg, extack))
 865				return 1;
 
 866		}
 867#ifdef CONFIG_IP_ROUTE_CLASSID
 868		if (cfg->fc_flow &&
 869		    cfg->fc_flow != nh->nh_tclassid)
 870			return 1;
 871#endif
 872		if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
 873		    (cfg->fc_gw_family &&
 874		     cfg->fc_gw_family != nh->fib_nh_gw_family))
 875			return 1;
 876
 877		if (cfg->fc_gw_family == AF_INET &&
 878		    cfg->fc_gw4 != nh->fib_nh_gw4)
 879			return 1;
 880
 881		if (cfg->fc_gw_family == AF_INET6 &&
 882		    ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
 883			return 1;
 884
 885		return 0;
 886	}
 887
 888#ifdef CONFIG_IP_ROUTE_MULTIPATH
 889	if (!cfg->fc_mp)
 890		return 0;
 891
 892	rtnh = cfg->fc_mp;
 893	remaining = cfg->fc_mp_len;
 894
 895	for_nexthops(fi) {
 896		int attrlen;
 897
 898		if (!rtnh_ok(rtnh, remaining))
 899			return -EINVAL;
 900
 901		if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
 902			return 1;
 903
 904		attrlen = rtnh_attrlen(rtnh);
 905		if (attrlen > 0) {
 906			struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
 907
 908			nla = nla_find(attrs, attrlen, RTA_GATEWAY);
 909			nlav = nla_find(attrs, attrlen, RTA_VIA);
 910			if (nla && nlav) {
 911				NL_SET_ERR_MSG(extack,
 912					       "Nexthop configuration can not contain both GATEWAY and VIA");
 913				return -EINVAL;
 914			}
 915
 916			if (nla) {
 917				if (nh->fib_nh_gw_family != AF_INET ||
 918				    nla_get_in_addr(nla) != nh->fib_nh_gw4)
 919					return 1;
 920			} else if (nlav) {
 921				struct fib_config cfg2;
 922				int err;
 923
 924				err = fib_gw_from_via(&cfg2, nlav, extack);
 925				if (err)
 926					return err;
 927
 928				switch (nh->fib_nh_gw_family) {
 929				case AF_INET:
 930					if (cfg2.fc_gw_family != AF_INET ||
 931					    cfg2.fc_gw4 != nh->fib_nh_gw4)
 932						return 1;
 933					break;
 934				case AF_INET6:
 935					if (cfg2.fc_gw_family != AF_INET6 ||
 936					    ipv6_addr_cmp(&cfg2.fc_gw6,
 937							  &nh->fib_nh_gw6))
 938						return 1;
 939					break;
 940				}
 941			}
 942
 943#ifdef CONFIG_IP_ROUTE_CLASSID
 944			nla = nla_find(attrs, attrlen, RTA_FLOW);
 945			if (nla && nla_get_u32(nla) != nh->nh_tclassid)
 946				return 1;
 947#endif
 948		}
 949
 950		rtnh = rtnh_next(rtnh, &remaining);
 951	} endfor_nexthops(fi);
 952#endif
 953	return 0;
 954}
 955
 956bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
 957{
 958	struct nlattr *nla;
 959	int remaining;
 960
 961	if (!cfg->fc_mx)
 962		return true;
 963
 964	nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
 965		int type = nla_type(nla);
 966		u32 fi_val, val;
 967
 968		if (!type)
 969			continue;
 970		if (type > RTAX_MAX)
 971			return false;
 972
 973		if (type == RTAX_CC_ALGO) {
 974			char tmp[TCP_CA_NAME_MAX];
 975			bool ecn_ca = false;
 976
 977			nla_strscpy(tmp, nla, sizeof(tmp));
 978			val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
 979		} else {
 980			if (nla_len(nla) != sizeof(u32))
 981				return false;
 982			val = nla_get_u32(nla);
 983		}
 984
 985		fi_val = fi->fib_metrics->metrics[type - 1];
 986		if (type == RTAX_FEATURES)
 987			fi_val &= ~DST_FEATURE_ECN_CA;
 988
 989		if (fi_val != val)
 990			return false;
 991	}
 992
 993	return true;
 994}
 995
 996static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
 997			      u32 table, struct netlink_ext_ack *extack)
 998{
 999	struct fib6_config cfg = {
1000		.fc_table = table,
1001		.fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1002		.fc_ifindex = nh->fib_nh_oif,
1003		.fc_gateway = nh->fib_nh_gw6,
1004	};
1005	struct fib6_nh fib6_nh = {};
1006	int err;
1007
1008	err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1009	if (!err) {
1010		nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1011		dev_hold(nh->fib_nh_dev);
1012		nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1013		nh->fib_nh_scope = RT_SCOPE_LINK;
1014
1015		ipv6_stub->fib6_nh_release(&fib6_nh);
1016	}
1017
1018	return err;
1019}
1020
1021/*
1022 * Picture
1023 * -------
1024 *
1025 * Semantics of nexthop is very messy by historical reasons.
1026 * We have to take into account, that:
1027 * a) gateway can be actually local interface address,
1028 *    so that gatewayed route is direct.
1029 * b) gateway must be on-link address, possibly
1030 *    described not by an ifaddr, but also by a direct route.
1031 * c) If both gateway and interface are specified, they should not
1032 *    contradict.
1033 * d) If we use tunnel routes, gateway could be not on-link.
1034 *
1035 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1036 * results in pretty ugly and hairy code with obscure logic.
1037 *
1038 * I chose to generalized it instead, so that the size
1039 * of code does not increase practically, but it becomes
1040 * much more general.
1041 * Every prefix is assigned a "scope" value: "host" is local address,
1042 * "link" is direct route,
1043 * [ ... "site" ... "interior" ... ]
1044 * and "universe" is true gateway route with global meaning.
1045 *
1046 * Every prefix refers to a set of "nexthop"s (gw, oif),
1047 * where gw must have narrower scope. This recursion stops
1048 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1049 * which means that gw is forced to be on link.
1050 *
1051 * Code is still hairy, but now it is apparently logically
1052 * consistent and very flexible. F.e. as by-product it allows
1053 * to co-exists in peace independent exterior and interior
1054 * routing processes.
1055 *
1056 * Normally it looks as following.
1057 *
1058 * {universe prefix}  -> (gw, oif) [scope link]
1059 *		  |
1060 *		  |-> {link prefix} -> (gw, oif) [scope local]
1061 *					|
1062 *					|-> {local prefix} (terminal node)
1063 */
1064static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1065			      u8 scope, struct netlink_ext_ack *extack)
1066{
1067	struct net_device *dev;
1068	struct fib_result res;
1069	int err = 0;
 
 
1070
1071	if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1072		unsigned int addr_type;
 
1073
1074		if (scope >= RT_SCOPE_LINK) {
1075			NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1076			return -EINVAL;
1077		}
1078		dev = __dev_get_by_index(net, nh->fib_nh_oif);
1079		if (!dev) {
1080			NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1081			return -ENODEV;
1082		}
1083		if (!(dev->flags & IFF_UP)) {
1084			NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1085			return -ENETDOWN;
1086		}
1087		addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1088		if (addr_type != RTN_UNICAST) {
1089			NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1090			return -EINVAL;
1091		}
1092		if (!netif_carrier_ok(dev))
1093			nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1094		nh->fib_nh_dev = dev;
1095		dev_hold(dev);
1096		nh->fib_nh_scope = RT_SCOPE_LINK;
1097		return 0;
1098	}
1099	rcu_read_lock();
1100	{
1101		struct fib_table *tbl = NULL;
1102		struct flowi4 fl4 = {
1103			.daddr = nh->fib_nh_gw4,
1104			.flowi4_scope = scope + 1,
1105			.flowi4_oif = nh->fib_nh_oif,
1106			.flowi4_iif = LOOPBACK_IFINDEX,
1107		};
1108
1109		/* It is not necessary, but requires a bit of thinking */
1110		if (fl4.flowi4_scope < RT_SCOPE_LINK)
1111			fl4.flowi4_scope = RT_SCOPE_LINK;
1112
1113		if (table && table != RT_TABLE_MAIN)
1114			tbl = fib_get_table(net, table);
1115
1116		if (tbl)
1117			err = fib_table_lookup(tbl, &fl4, &res,
1118					       FIB_LOOKUP_IGNORE_LINKSTATE |
1119					       FIB_LOOKUP_NOREF);
1120
1121		/* on error or if no table given do full lookup. This
1122		 * is needed for example when nexthops are in the local
1123		 * table rather than the given table
1124		 */
1125		if (!tbl || err) {
1126			err = fib_lookup(net, &fl4, &res,
1127					 FIB_LOOKUP_IGNORE_LINKSTATE);
1128		}
1129
1130		if (err) {
1131			NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1132			goto out;
 
 
 
 
 
 
 
 
 
 
 
 
 
1133		}
1134	}
1135
1136	err = -EINVAL;
1137	if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1138		NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139		goto out;
1140	}
1141	nh->fib_nh_scope = res.scope;
1142	nh->fib_nh_oif = FIB_RES_OIF(res);
1143	nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1144	if (!dev) {
1145		NL_SET_ERR_MSG(extack,
1146			       "No egress device for nexthop gateway");
1147		goto out;
1148	}
1149	dev_hold(dev);
1150	if (!netif_carrier_ok(dev))
1151		nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1152	err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1153out:
1154	rcu_read_unlock();
1155	return err;
1156}
1157
1158static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1159			      struct netlink_ext_ack *extack)
1160{
1161	struct in_device *in_dev;
1162	int err;
 
1163
1164	if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1165		NL_SET_ERR_MSG(extack,
1166			       "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1167		return -EINVAL;
1168	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1169
1170	rcu_read_lock();
 
1171
1172	err = -ENODEV;
1173	in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1174	if (!in_dev)
1175		goto out;
1176	err = -ENETDOWN;
1177	if (!(in_dev->dev->flags & IFF_UP)) {
1178		NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1179		goto out;
 
 
 
 
 
 
1180	}
1181
1182	nh->fib_nh_dev = in_dev->dev;
1183	dev_hold(nh->fib_nh_dev);
1184	nh->fib_nh_scope = RT_SCOPE_HOST;
1185	if (!netif_carrier_ok(nh->fib_nh_dev))
1186		nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1187	err = 0;
1188out:
1189	rcu_read_unlock();
1190	return err;
1191}
1192
1193int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1194		 struct netlink_ext_ack *extack)
1195{
1196	int err;
1197
1198	if (nh->fib_nh_gw_family == AF_INET)
1199		err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1200	else if (nh->fib_nh_gw_family == AF_INET6)
1201		err = fib_check_nh_v6_gw(net, nh, table, extack);
1202	else
1203		err = fib_check_nh_nongw(net, nh, extack);
1204
1205	return err;
1206}
1207
1208static inline unsigned int fib_laddr_hashfn(__be32 val)
1209{
1210	unsigned int mask = (fib_info_hash_size - 1);
1211
1212	return ((__force u32)val ^
1213		((__force u32)val >> 7) ^
1214		((__force u32)val >> 14)) & mask;
1215}
1216
1217static struct hlist_head *fib_info_hash_alloc(int bytes)
1218{
1219	if (bytes <= PAGE_SIZE)
1220		return kzalloc(bytes, GFP_KERNEL);
1221	else
1222		return (struct hlist_head *)
1223			__get_free_pages(GFP_KERNEL | __GFP_ZERO,
1224					 get_order(bytes));
1225}
1226
1227static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1228{
1229	if (!hash)
1230		return;
1231
1232	if (bytes <= PAGE_SIZE)
1233		kfree(hash);
1234	else
1235		free_pages((unsigned long) hash, get_order(bytes));
1236}
1237
1238static void fib_info_hash_move(struct hlist_head *new_info_hash,
1239			       struct hlist_head *new_laddrhash,
1240			       unsigned int new_size)
1241{
1242	struct hlist_head *old_info_hash, *old_laddrhash;
1243	unsigned int old_size = fib_info_hash_size;
1244	unsigned int i, bytes;
1245
1246	spin_lock_bh(&fib_info_lock);
1247	old_info_hash = fib_info_hash;
1248	old_laddrhash = fib_info_laddrhash;
1249	fib_info_hash_size = new_size;
1250
1251	for (i = 0; i < old_size; i++) {
1252		struct hlist_head *head = &fib_info_hash[i];
1253		struct hlist_node *n;
1254		struct fib_info *fi;
1255
1256		hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1257			struct hlist_head *dest;
1258			unsigned int new_hash;
1259
1260			new_hash = fib_info_hashfn(fi);
1261			dest = &new_info_hash[new_hash];
1262			hlist_add_head(&fi->fib_hash, dest);
1263		}
1264	}
1265	fib_info_hash = new_info_hash;
1266
1267	for (i = 0; i < old_size; i++) {
1268		struct hlist_head *lhead = &fib_info_laddrhash[i];
1269		struct hlist_node *n;
1270		struct fib_info *fi;
1271
1272		hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1273			struct hlist_head *ldest;
1274			unsigned int new_hash;
1275
1276			new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1277			ldest = &new_laddrhash[new_hash];
1278			hlist_add_head(&fi->fib_lhash, ldest);
1279		}
1280	}
1281	fib_info_laddrhash = new_laddrhash;
1282
1283	spin_unlock_bh(&fib_info_lock);
1284
1285	bytes = old_size * sizeof(struct hlist_head *);
1286	fib_info_hash_free(old_info_hash, bytes);
1287	fib_info_hash_free(old_laddrhash, bytes);
1288}
1289
1290__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1291				 unsigned char scope)
1292{
1293	struct fib_nh *nh;
1294
1295	if (nhc->nhc_family != AF_INET)
1296		return inet_select_addr(nhc->nhc_dev, 0, scope);
1297
1298	nh = container_of(nhc, struct fib_nh, nh_common);
1299	nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1300	nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1301
1302	return nh->nh_saddr;
1303}
1304
1305__be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1306{
1307	struct fib_nh_common *nhc = res->nhc;
1308
1309	if (res->fi->fib_prefsrc)
1310		return res->fi->fib_prefsrc;
1311
1312	if (nhc->nhc_family == AF_INET) {
1313		struct fib_nh *nh;
1314
1315		nh = container_of(nhc, struct fib_nh, nh_common);
1316		if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1317			return nh->nh_saddr;
1318	}
1319
1320	return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1321}
1322
1323static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1324{
1325	if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1326	    fib_prefsrc != cfg->fc_dst) {
1327		u32 tb_id = cfg->fc_table;
1328		int rc;
1329
1330		if (tb_id == RT_TABLE_MAIN)
1331			tb_id = RT_TABLE_LOCAL;
1332
1333		rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1334					  fib_prefsrc, tb_id);
1335
1336		if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1337			rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1338						  fib_prefsrc, RT_TABLE_LOCAL);
1339		}
1340
1341		if (rc != RTN_LOCAL)
1342			return false;
1343	}
1344	return true;
1345}
1346
1347struct fib_info *fib_create_info(struct fib_config *cfg,
1348				 struct netlink_ext_ack *extack)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1349{
1350	int err;
1351	struct fib_info *fi = NULL;
1352	struct nexthop *nh = NULL;
1353	struct fib_info *ofi;
1354	int nhs = 1;
1355	struct net *net = cfg->fc_nlinfo.nl_net;
1356
1357	if (cfg->fc_type > RTN_MAX)
1358		goto err_inval;
1359
1360	/* Fast check to catch the most weird cases */
1361	if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1362		NL_SET_ERR_MSG(extack, "Invalid scope");
1363		goto err_inval;
1364	}
1365
1366	if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1367		NL_SET_ERR_MSG(extack,
1368			       "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1369		goto err_inval;
1370	}
1371
1372	if (cfg->fc_nh_id) {
1373		if (!cfg->fc_mx) {
1374			fi = fib_find_info_nh(net, cfg);
1375			if (fi) {
1376				fi->fib_treeref++;
1377				return fi;
1378			}
1379		}
1380
1381		nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1382		if (!nh) {
1383			NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1384			goto err_inval;
1385		}
1386		nhs = 0;
1387	}
1388
1389#ifdef CONFIG_IP_ROUTE_MULTIPATH
1390	if (cfg->fc_mp) {
1391		nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1392		if (nhs == 0)
1393			goto err_inval;
1394	}
1395#endif
1396
1397	err = -ENOBUFS;
1398	if (fib_info_cnt >= fib_info_hash_size) {
1399		unsigned int new_size = fib_info_hash_size << 1;
1400		struct hlist_head *new_info_hash;
1401		struct hlist_head *new_laddrhash;
1402		unsigned int bytes;
1403
1404		if (!new_size)
1405			new_size = 16;
1406		bytes = new_size * sizeof(struct hlist_head *);
1407		new_info_hash = fib_info_hash_alloc(bytes);
1408		new_laddrhash = fib_info_hash_alloc(bytes);
1409		if (!new_info_hash || !new_laddrhash) {
1410			fib_info_hash_free(new_info_hash, bytes);
1411			fib_info_hash_free(new_laddrhash, bytes);
1412		} else
1413			fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1414
1415		if (!fib_info_hash_size)
1416			goto failure;
1417	}
1418
1419	fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1420	if (!fi)
1421		goto failure;
1422	fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1423					      cfg->fc_mx_len, extack);
1424	if (IS_ERR(fi->fib_metrics)) {
1425		err = PTR_ERR(fi->fib_metrics);
1426		kfree(fi);
1427		return ERR_PTR(err);
1428	}
1429
1430	fib_info_cnt++;
 
 
 
 
 
 
 
1431	fi->fib_net = net;
1432	fi->fib_protocol = cfg->fc_protocol;
1433	fi->fib_scope = cfg->fc_scope;
1434	fi->fib_flags = cfg->fc_flags;
1435	fi->fib_priority = cfg->fc_priority;
1436	fi->fib_prefsrc = cfg->fc_prefsrc;
1437	fi->fib_type = cfg->fc_type;
1438	fi->fib_tb_id = cfg->fc_table;
1439
1440	fi->fib_nhs = nhs;
1441	if (nh) {
1442		if (!nexthop_get(nh)) {
1443			NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1444			err = -EINVAL;
1445		} else {
1446			err = 0;
1447			fi->nh = nh;
1448		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1449	} else {
1450		change_nexthops(fi) {
1451			nexthop_nh->nh_parent = fi;
1452		} endfor_nexthops(fi)
1453
1454		if (cfg->fc_mp)
1455			err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1456					  extack);
1457		else
1458			err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1459	}
1460
1461	if (err != 0)
1462		goto failure;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1463
1464	if (fib_props[cfg->fc_type].error) {
1465		if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1466			NL_SET_ERR_MSG(extack,
1467				       "Gateway, device and multipath can not be specified for this route type");
1468			goto err_inval;
1469		}
1470		goto link_it;
1471	} else {
1472		switch (cfg->fc_type) {
1473		case RTN_UNICAST:
1474		case RTN_LOCAL:
1475		case RTN_BROADCAST:
1476		case RTN_ANYCAST:
1477		case RTN_MULTICAST:
1478			break;
1479		default:
1480			NL_SET_ERR_MSG(extack, "Invalid route type");
1481			goto err_inval;
1482		}
1483	}
1484
1485	if (cfg->fc_scope > RT_SCOPE_HOST) {
1486		NL_SET_ERR_MSG(extack, "Invalid scope");
1487		goto err_inval;
1488	}
1489
1490	if (fi->nh) {
1491		err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1492		if (err)
1493			goto failure;
1494	} else if (cfg->fc_scope == RT_SCOPE_HOST) {
1495		struct fib_nh *nh = fi->fib_nh;
1496
1497		/* Local address is added. */
1498		if (nhs != 1) {
1499			NL_SET_ERR_MSG(extack,
1500				       "Route with host scope can not have multiple nexthops");
1501			goto err_inval;
1502		}
1503		if (nh->fib_nh_gw_family) {
1504			NL_SET_ERR_MSG(extack,
1505				       "Route with host scope can not have a gateway");
1506			goto err_inval;
1507		}
1508		nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1509		nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1510		err = -ENODEV;
1511		if (!nh->fib_nh_dev)
1512			goto failure;
1513	} else {
1514		int linkdown = 0;
1515
1516		change_nexthops(fi) {
1517			err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1518					   cfg->fc_table, cfg->fc_scope,
1519					   extack);
1520			if (err != 0)
1521				goto failure;
1522			if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1523				linkdown++;
1524		} endfor_nexthops(fi)
1525		if (linkdown == fi->fib_nhs)
1526			fi->fib_flags |= RTNH_F_LINKDOWN;
1527	}
1528
1529	if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1530		NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1531		goto err_inval;
1532	}
1533
1534	if (!fi->nh) {
1535		change_nexthops(fi) {
1536			fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1537						  fi->fib_scope);
1538			if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1539				fi->fib_nh_is_v6 = true;
1540		} endfor_nexthops(fi)
1541
1542		fib_rebalance(fi);
1543	}
1544
1545link_it:
1546	ofi = fib_find_info(fi);
1547	if (ofi) {
1548		fi->fib_dead = 1;
1549		free_fib_info(fi);
1550		ofi->fib_treeref++;
1551		return ofi;
1552	}
1553
1554	fi->fib_treeref++;
1555	refcount_set(&fi->fib_clntref, 1);
1556	spin_lock_bh(&fib_info_lock);
1557	hlist_add_head(&fi->fib_hash,
1558		       &fib_info_hash[fib_info_hashfn(fi)]);
1559	if (fi->fib_prefsrc) {
1560		struct hlist_head *head;
1561
1562		head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1563		hlist_add_head(&fi->fib_lhash, head);
1564	}
1565	if (fi->nh) {
1566		list_add(&fi->nh_list, &nh->fi_list);
1567	} else {
1568		change_nexthops(fi) {
1569			struct hlist_head *head;
1570			unsigned int hash;
1571
1572			if (!nexthop_nh->fib_nh_dev)
1573				continue;
1574			hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1575			head = &fib_info_devhash[hash];
1576			hlist_add_head(&nexthop_nh->nh_hash, head);
1577		} endfor_nexthops(fi)
1578	}
1579	spin_unlock_bh(&fib_info_lock);
1580	return fi;
1581
1582err_inval:
1583	err = -EINVAL;
1584
1585failure:
1586	if (fi) {
1587		fi->fib_dead = 1;
1588		free_fib_info(fi);
1589	}
1590
1591	return ERR_PTR(err);
1592}
1593
1594int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1595		     u8 rt_family, unsigned char *flags, bool skip_oif)
1596{
1597	if (nhc->nhc_flags & RTNH_F_DEAD)
1598		*flags |= RTNH_F_DEAD;
1599
1600	if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1601		*flags |= RTNH_F_LINKDOWN;
1602
1603		rcu_read_lock();
1604		switch (nhc->nhc_family) {
1605		case AF_INET:
1606			if (ip_ignore_linkdown(nhc->nhc_dev))
1607				*flags |= RTNH_F_DEAD;
1608			break;
1609		case AF_INET6:
1610			if (ip6_ignore_linkdown(nhc->nhc_dev))
1611				*flags |= RTNH_F_DEAD;
1612			break;
1613		}
1614		rcu_read_unlock();
1615	}
1616
1617	switch (nhc->nhc_gw_family) {
1618	case AF_INET:
1619		if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1620			goto nla_put_failure;
1621		break;
1622	case AF_INET6:
1623		/* if gateway family does not match nexthop family
1624		 * gateway is encoded as RTA_VIA
1625		 */
1626		if (rt_family != nhc->nhc_gw_family) {
1627			int alen = sizeof(struct in6_addr);
1628			struct nlattr *nla;
1629			struct rtvia *via;
1630
1631			nla = nla_reserve(skb, RTA_VIA, alen + 2);
1632			if (!nla)
1633				goto nla_put_failure;
1634
1635			via = nla_data(nla);
1636			via->rtvia_family = AF_INET6;
1637			memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1638		} else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1639					    &nhc->nhc_gw.ipv6) < 0) {
1640			goto nla_put_failure;
1641		}
1642		break;
1643	}
1644
1645	*flags |= (nhc->nhc_flags &
1646		   (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
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, u32 nh_tclassid)
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	if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1685		goto nla_put_failure;
1686
1687	/* length of rtnetlink header + attributes */
1688	rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1689
1690	return 0;
1691
1692nla_put_failure:
1693	return -EMSGSIZE;
1694}
1695EXPORT_SYMBOL_GPL(fib_add_nexthop);
1696#endif
1697
1698#ifdef CONFIG_IP_ROUTE_MULTIPATH
1699static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1700{
1701	struct nlattr *mp;
1702
1703	mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1704	if (!mp)
1705		goto nla_put_failure;
1706
1707	if (unlikely(fi->nh)) {
1708		if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1709			goto nla_put_failure;
1710		goto mp_end;
1711	}
1712
1713	for_nexthops(fi) {
1714		u32 nh_tclassid = 0;
1715#ifdef CONFIG_IP_ROUTE_CLASSID
1716		nh_tclassid = nh->nh_tclassid;
1717#endif
1718		if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1719				    AF_INET, nh_tclassid) < 0)
1720			goto nla_put_failure;
1721	} endfor_nexthops(fi);
1722
1723mp_end:
1724	nla_nest_end(skb, mp);
1725
1726	return 0;
1727
1728nla_put_failure:
1729	return -EMSGSIZE;
1730}
1731#else
1732static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1733{
1734	return 0;
1735}
1736#endif
1737
1738int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1739		  const struct fib_rt_info *fri, unsigned int flags)
 
1740{
1741	unsigned int nhs = fib_info_num_path(fri->fi);
1742	struct fib_info *fi = fri->fi;
1743	u32 tb_id = fri->tb_id;
1744	struct nlmsghdr *nlh;
1745	struct rtmsg *rtm;
1746
1747	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1748	if (!nlh)
1749		return -EMSGSIZE;
1750
1751	rtm = nlmsg_data(nlh);
1752	rtm->rtm_family = AF_INET;
1753	rtm->rtm_dst_len = fri->dst_len;
1754	rtm->rtm_src_len = 0;
1755	rtm->rtm_tos = fri->tos;
1756	if (tb_id < 256)
1757		rtm->rtm_table = tb_id;
1758	else
1759		rtm->rtm_table = RT_TABLE_COMPAT;
1760	if (nla_put_u32(skb, RTA_TABLE, tb_id))
1761		goto nla_put_failure;
1762	rtm->rtm_type = fri->type;
1763	rtm->rtm_flags = fi->fib_flags;
1764	rtm->rtm_scope = fi->fib_scope;
1765	rtm->rtm_protocol = fi->fib_protocol;
1766
1767	if (rtm->rtm_dst_len &&
1768	    nla_put_in_addr(skb, RTA_DST, fri->dst))
1769		goto nla_put_failure;
1770	if (fi->fib_priority &&
1771	    nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1772		goto nla_put_failure;
1773	if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1774		goto nla_put_failure;
1775
1776	if (fi->fib_prefsrc &&
1777	    nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1778		goto nla_put_failure;
 
 
1779
1780	if (fi->nh) {
1781		if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1782			goto nla_put_failure;
1783		if (nexthop_is_blackhole(fi->nh))
1784			rtm->rtm_type = RTN_BLACKHOLE;
1785		if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1786			goto offload;
 
 
 
 
 
 
 
 
 
 
 
 
1787	}
 
 
 
 
1788
1789	if (nhs == 1) {
1790		const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1791		unsigned char flags = 0;
1792
1793		if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1794			goto nla_put_failure;
1795
1796		rtm->rtm_flags = flags;
1797#ifdef CONFIG_IP_ROUTE_CLASSID
1798		if (nhc->nhc_family == AF_INET) {
1799			struct fib_nh *nh;
 
 
 
 
 
 
 
 
 
 
 
 
1800
1801			nh = container_of(nhc, struct fib_nh, nh_common);
 
 
 
1802			if (nh->nh_tclassid &&
1803			    nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1804				goto nla_put_failure;
1805		}
1806#endif
1807	} else {
1808		if (fib_add_multipath(skb, fi) < 0)
1809			goto nla_put_failure;
1810	}
1811
1812offload:
1813	if (fri->offload)
1814		rtm->rtm_flags |= RTM_F_OFFLOAD;
1815	if (fri->trap)
1816		rtm->rtm_flags |= RTM_F_TRAP;
1817	if (fri->offload_failed)
1818		rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1819
 
 
 
1820	nlmsg_end(skb, nlh);
1821	return 0;
1822
1823nla_put_failure:
1824	nlmsg_cancel(skb, nlh);
1825	return -EMSGSIZE;
1826}
1827
1828/*
1829 * Update FIB if:
1830 * - local address disappeared -> we must delete all the entries
1831 *   referring to it.
1832 * - device went down -> we must shutdown all nexthops going via it.
1833 */
1834int fib_sync_down_addr(struct net_device *dev, __be32 local)
1835{
1836	int ret = 0;
1837	unsigned int hash = fib_laddr_hashfn(local);
1838	struct hlist_head *head = &fib_info_laddrhash[hash];
1839	int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1840	struct net *net = dev_net(dev);
1841	struct fib_info *fi;
1842
1843	if (!fib_info_laddrhash || local == 0)
1844		return 0;
1845
1846	hlist_for_each_entry(fi, head, fib_lhash) {
1847		if (!net_eq(fi->fib_net, net) ||
1848		    fi->fib_tb_id != tb_id)
1849			continue;
1850		if (fi->fib_prefsrc == local) {
1851			fi->fib_flags |= RTNH_F_DEAD;
1852			ret++;
1853		}
1854	}
1855	return ret;
1856}
1857
1858static int call_fib_nh_notifiers(struct fib_nh *nh,
1859				 enum fib_event_type event_type)
1860{
1861	bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1862	struct fib_nh_notifier_info info = {
1863		.fib_nh = nh,
1864	};
1865
1866	switch (event_type) {
1867	case FIB_EVENT_NH_ADD:
1868		if (nh->fib_nh_flags & RTNH_F_DEAD)
1869			break;
1870		if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1871			break;
1872		return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1873					   &info.info);
1874	case FIB_EVENT_NH_DEL:
1875		if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1876		    (nh->fib_nh_flags & RTNH_F_DEAD))
1877			return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1878						   event_type, &info.info);
1879		break;
1880	default:
1881		break;
1882	}
1883
1884	return NOTIFY_DONE;
1885}
1886
1887/* Update the PMTU of exceptions when:
1888 * - the new MTU of the first hop becomes smaller than the PMTU
1889 * - the old MTU was the same as the PMTU, and it limited discovery of
1890 *   larger MTUs on the path. With that limit raised, we can now
1891 *   discover larger MTUs
1892 * A special case is locked exceptions, for which the PMTU is smaller
1893 * than the minimal accepted PMTU:
1894 * - if the new MTU is greater than the PMTU, don't make any change
1895 * - otherwise, unlock and set PMTU
1896 */
1897void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1898{
1899	struct fnhe_hash_bucket *bucket;
1900	int i;
1901
1902	bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1903	if (!bucket)
1904		return;
1905
1906	for (i = 0; i < FNHE_HASH_SIZE; i++) {
1907		struct fib_nh_exception *fnhe;
1908
1909		for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1910		     fnhe;
1911		     fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1912			if (fnhe->fnhe_mtu_locked) {
1913				if (new <= fnhe->fnhe_pmtu) {
1914					fnhe->fnhe_pmtu = new;
1915					fnhe->fnhe_mtu_locked = false;
1916				}
1917			} else if (new < fnhe->fnhe_pmtu ||
1918				   orig == fnhe->fnhe_pmtu) {
1919				fnhe->fnhe_pmtu = new;
1920			}
1921		}
1922	}
1923}
1924
1925void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1926{
1927	unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1928	struct hlist_head *head = &fib_info_devhash[hash];
1929	struct fib_nh *nh;
1930
1931	hlist_for_each_entry(nh, head, nh_hash) {
1932		if (nh->fib_nh_dev == dev)
1933			fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1934	}
1935}
1936
1937/* Event              force Flags           Description
1938 * NETDEV_CHANGE      0     LINKDOWN        Carrier OFF, not for scope host
1939 * NETDEV_DOWN        0     LINKDOWN|DEAD   Link down, not for scope host
1940 * NETDEV_DOWN        1     LINKDOWN|DEAD   Last address removed
1941 * NETDEV_UNREGISTER  1     LINKDOWN|DEAD   Device removed
1942 *
1943 * only used when fib_nh is built into fib_info
1944 */
1945int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1946{
1947	int ret = 0;
1948	int scope = RT_SCOPE_NOWHERE;
1949	struct fib_info *prev_fi = NULL;
1950	unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1951	struct hlist_head *head = &fib_info_devhash[hash];
1952	struct fib_nh *nh;
1953
1954	if (force)
1955		scope = -1;
1956
1957	hlist_for_each_entry(nh, head, nh_hash) {
1958		struct fib_info *fi = nh->nh_parent;
1959		int dead;
1960
1961		BUG_ON(!fi->fib_nhs);
1962		if (nh->fib_nh_dev != dev || fi == prev_fi)
1963			continue;
1964		prev_fi = fi;
1965		dead = 0;
1966		change_nexthops(fi) {
1967			if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1968				dead++;
1969			else if (nexthop_nh->fib_nh_dev == dev &&
1970				 nexthop_nh->fib_nh_scope != scope) {
1971				switch (event) {
1972				case NETDEV_DOWN:
1973				case NETDEV_UNREGISTER:
1974					nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1975					fallthrough;
1976				case NETDEV_CHANGE:
1977					nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1978					break;
1979				}
1980				call_fib_nh_notifiers(nexthop_nh,
1981						      FIB_EVENT_NH_DEL);
1982				dead++;
1983			}
1984#ifdef CONFIG_IP_ROUTE_MULTIPATH
1985			if (event == NETDEV_UNREGISTER &&
1986			    nexthop_nh->fib_nh_dev == dev) {
1987				dead = fi->fib_nhs;
1988				break;
1989			}
1990#endif
1991		} endfor_nexthops(fi)
1992		if (dead == fi->fib_nhs) {
1993			switch (event) {
1994			case NETDEV_DOWN:
1995			case NETDEV_UNREGISTER:
1996				fi->fib_flags |= RTNH_F_DEAD;
1997				fallthrough;
1998			case NETDEV_CHANGE:
1999				fi->fib_flags |= RTNH_F_LINKDOWN;
2000				break;
2001			}
2002			ret++;
2003		}
2004
2005		fib_rebalance(fi);
2006	}
2007
2008	return ret;
2009}
2010
2011/* Must be invoked inside of an RCU protected region.  */
2012static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2013{
2014	struct fib_info *fi = NULL, *last_resort = NULL;
2015	struct hlist_head *fa_head = res->fa_head;
2016	struct fib_table *tb = res->table;
2017	u8 slen = 32 - res->prefixlen;
2018	int order = -1, last_idx = -1;
2019	struct fib_alias *fa, *fa1 = NULL;
2020	u32 last_prio = res->fi->fib_priority;
2021	u8 last_tos = 0;
2022
2023	hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2024		struct fib_info *next_fi = fa->fa_info;
2025		struct fib_nh_common *nhc;
2026
2027		if (fa->fa_slen != slen)
2028			continue;
2029		if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2030			continue;
2031		if (fa->tb_id != tb->tb_id)
2032			continue;
2033		if (next_fi->fib_priority > last_prio &&
2034		    fa->fa_tos == last_tos) {
2035			if (last_tos)
2036				continue;
2037			break;
2038		}
2039		if (next_fi->fib_flags & RTNH_F_DEAD)
2040			continue;
2041		last_tos = fa->fa_tos;
2042		last_prio = next_fi->fib_priority;
2043
2044		if (next_fi->fib_scope != res->scope ||
2045		    fa->fa_type != RTN_UNICAST)
2046			continue;
2047
2048		nhc = fib_info_nhc(next_fi, 0);
2049		if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2050			continue;
2051
2052		fib_alias_accessed(fa);
2053
2054		if (!fi) {
2055			if (next_fi != res->fi)
2056				break;
2057			fa1 = fa;
2058		} else if (!fib_detect_death(fi, order, &last_resort,
2059					     &last_idx, fa1->fa_default)) {
2060			fib_result_assign(res, fi);
2061			fa1->fa_default = order;
2062			goto out;
2063		}
2064		fi = next_fi;
2065		order++;
2066	}
2067
2068	if (order <= 0 || !fi) {
2069		if (fa1)
2070			fa1->fa_default = -1;
2071		goto out;
2072	}
2073
2074	if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2075			      fa1->fa_default)) {
2076		fib_result_assign(res, fi);
2077		fa1->fa_default = order;
2078		goto out;
2079	}
2080
2081	if (last_idx >= 0)
2082		fib_result_assign(res, last_resort);
2083	fa1->fa_default = last_idx;
2084out:
2085	return;
2086}
2087
2088/*
2089 * Dead device goes up. We wake up dead nexthops.
2090 * It takes sense only on multipath routes.
2091 *
2092 * only used when fib_nh is built into fib_info
2093 */
2094int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2095{
2096	struct fib_info *prev_fi;
2097	unsigned int hash;
2098	struct hlist_head *head;
2099	struct fib_nh *nh;
2100	int ret;
2101
2102	if (!(dev->flags & IFF_UP))
2103		return 0;
2104
2105	if (nh_flags & RTNH_F_DEAD) {
2106		unsigned int flags = dev_get_flags(dev);
2107
2108		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2109			nh_flags |= RTNH_F_LINKDOWN;
2110	}
2111
2112	prev_fi = NULL;
2113	hash = fib_devindex_hashfn(dev->ifindex);
2114	head = &fib_info_devhash[hash];
2115	ret = 0;
2116
2117	hlist_for_each_entry(nh, head, nh_hash) {
2118		struct fib_info *fi = nh->nh_parent;
2119		int alive;
2120
2121		BUG_ON(!fi->fib_nhs);
2122		if (nh->fib_nh_dev != dev || fi == prev_fi)
2123			continue;
2124
2125		prev_fi = fi;
2126		alive = 0;
2127		change_nexthops(fi) {
2128			if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2129				alive++;
2130				continue;
2131			}
2132			if (!nexthop_nh->fib_nh_dev ||
2133			    !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2134				continue;
2135			if (nexthop_nh->fib_nh_dev != dev ||
2136			    !__in_dev_get_rtnl(dev))
2137				continue;
2138			alive++;
2139			nexthop_nh->fib_nh_flags &= ~nh_flags;
2140			call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2141		} endfor_nexthops(fi)
2142
2143		if (alive > 0) {
2144			fi->fib_flags &= ~nh_flags;
2145			ret++;
2146		}
2147
2148		fib_rebalance(fi);
2149	}
2150
2151	return ret;
2152}
2153
2154#ifdef CONFIG_IP_ROUTE_MULTIPATH
2155static bool fib_good_nh(const struct fib_nh *nh)
2156{
2157	int state = NUD_REACHABLE;
2158
2159	if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2160		struct neighbour *n;
2161
2162		rcu_read_lock_bh();
2163
2164		if (likely(nh->fib_nh_gw_family == AF_INET))
2165			n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2166						   (__force u32)nh->fib_nh_gw4);
2167		else if (nh->fib_nh_gw_family == AF_INET6)
2168			n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2169							   &nh->fib_nh_gw6);
2170		else
2171			n = NULL;
2172		if (n)
2173			state = n->nud_state;
2174
2175		rcu_read_unlock_bh();
2176	}
2177
2178	return !!(state & NUD_VALID);
2179}
2180
2181void fib_select_multipath(struct fib_result *res, int hash)
2182{
2183	struct fib_info *fi = res->fi;
2184	struct net *net = fi->fib_net;
2185	bool first = false;
2186
2187	if (unlikely(res->fi->nh)) {
2188		nexthop_path_fib_result(res, hash);
2189		return;
2190	}
2191
2192	change_nexthops(fi) {
2193		if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2194			if (!fib_good_nh(nexthop_nh))
2195				continue;
2196			if (!first) {
2197				res->nh_sel = nhsel;
2198				res->nhc = &nexthop_nh->nh_common;
2199				first = true;
2200			}
2201		}
2202
2203		if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2204			continue;
2205
2206		res->nh_sel = nhsel;
2207		res->nhc = &nexthop_nh->nh_common;
2208		return;
2209	} endfor_nexthops(fi);
 
 
 
2210}
2211#endif
2212
2213void fib_select_path(struct net *net, struct fib_result *res,
2214		     struct flowi4 *fl4, const struct sk_buff *skb)
2215{
2216	if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2217		goto check_saddr;
2218
2219#ifdef CONFIG_IP_ROUTE_MULTIPATH
2220	if (fib_info_num_path(res->fi) > 1) {
2221		int h = fib_multipath_hash(net, fl4, skb, NULL);
 
2222
2223		fib_select_multipath(res, h);
2224	}
2225	else
2226#endif
2227	if (!res->prefixlen &&
2228	    res->table->tb_num_default > 1 &&
2229	    res->type == RTN_UNICAST)
2230		fib_select_default(fl4, res);
2231
2232check_saddr:
2233	if (!fl4->saddr)
2234		fl4->saddr = fib_result_prefsrc(net, res);
2235}