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linux_dsm_epyc7002/net/ipv4/fib_semantics.c
Eric Dumazet 3fb07daff8 ipv4: add reference counting to metrics 
Andrey Konovalov reported crashes in ipv4_mtu()

I could reproduce the issue with KASAN kernels, between
10.246.7.151 and 10.246.7.152 :

1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 &

2) At the same time run following loop :
while :
do
 ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
 ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
done

Cong Wang attempted to add back rt->fi in commit
82486aa6f1 ("ipv4: restore rt->fi for reference counting")
but this proved to add some issues that were complex to solve.

Instead, I suggested to add a refcount to the metrics themselves,
being a standalone object (in particular, no reference to other objects)

I tried to make this patch as small as possible to ease its backport,
instead of being super clean. Note that we believe that only ipv4 dst
need to take care of the metric refcount. But if this is wrong,
this patch adds the basic infrastructure to extend this to other
families.

Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang
for his efforts on this problem.

Fixes: 2860583fe8 ("ipv4: Kill rt->fi")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-26 14:57:07 -04:00

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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 Forwarding Information Base: semantics.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <net/arp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <net/netlink.h>
#include <net/nexthop.h>
#include <net/lwtunnel.h>
#include "fib_lookup.h"
static DEFINE_SPINLOCK(fib_info_lock);
static struct hlist_head *fib_info_hash;
static struct hlist_head *fib_info_laddrhash;
static unsigned int fib_info_hash_size;
static unsigned int fib_info_cnt;
#define DEVINDEX_HASHBITS 8
#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
#ifdef CONFIG_IP_ROUTE_MULTIPATH
#define for_nexthops(fi) { \
int nhsel; const struct fib_nh *nh; \
for (nhsel = 0, nh = (fi)->fib_nh; \
nhsel < (fi)->fib_nhs; \
nh++, nhsel++)
#define change_nexthops(fi) { \
int nhsel; struct fib_nh *nexthop_nh; \
for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
nhsel < (fi)->fib_nhs; \
nexthop_nh++, nhsel++)
#else /* CONFIG_IP_ROUTE_MULTIPATH */
/* Hope, that gcc will optimize it to get rid of dummy loop */
#define for_nexthops(fi) { \
int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
for (nhsel = 0; nhsel < 1; nhsel++)
#define change_nexthops(fi) { \
int nhsel; \
struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
for (nhsel = 0; nhsel < 1; nhsel++)
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
#define endfor_nexthops(fi) }
const struct fib_prop fib_props[RTN_MAX + 1] = {
[RTN_UNSPEC] = {
.error = 0,
.scope = RT_SCOPE_NOWHERE,
},
[RTN_UNICAST] = {
.error = 0,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_LOCAL] = {
.error = 0,
.scope = RT_SCOPE_HOST,
},
[RTN_BROADCAST] = {
.error = 0,
.scope = RT_SCOPE_LINK,
},
[RTN_ANYCAST] = {
.error = 0,
.scope = RT_SCOPE_LINK,
},
[RTN_MULTICAST] = {
.error = 0,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_BLACKHOLE] = {
.error = -EINVAL,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_UNREACHABLE] = {
.error = -EHOSTUNREACH,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_PROHIBIT] = {
.error = -EACCES,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_THROW] = {
.error = -EAGAIN,
.scope = RT_SCOPE_UNIVERSE,
},
[RTN_NAT] = {
.error = -EINVAL,
.scope = RT_SCOPE_NOWHERE,
},
[RTN_XRESOLVE] = {
.error = -EINVAL,
.scope = RT_SCOPE_NOWHERE,
},
};
static void rt_fibinfo_free(struct rtable __rcu **rtp)
{
struct rtable *rt = rcu_dereference_protected(*rtp, 1);
if (!rt)
return;
/* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
* because we waited an RCU grace period before calling
* free_fib_info_rcu()
*/
dst_free(&rt->dst);
}
static void free_nh_exceptions(struct fib_nh *nh)
{
struct fnhe_hash_bucket *hash;
int i;
hash = rcu_dereference_protected(nh->nh_exceptions, 1);
if (!hash)
return;
for (i = 0; i < FNHE_HASH_SIZE; i++) {
struct fib_nh_exception *fnhe;
fnhe = rcu_dereference_protected(hash[i].chain, 1);
while (fnhe) {
struct fib_nh_exception *next;
next = rcu_dereference_protected(fnhe->fnhe_next, 1);
rt_fibinfo_free(&fnhe->fnhe_rth_input);
rt_fibinfo_free(&fnhe->fnhe_rth_output);
kfree(fnhe);
fnhe = next;
}
}
kfree(hash);
}
static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
{
int cpu;
if (!rtp)
return;
for_each_possible_cpu(cpu) {
struct rtable *rt;
rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
if (rt)
dst_free(&rt->dst);
}
free_percpu(rtp);
}
/* Release a nexthop info record */
static void free_fib_info_rcu(struct rcu_head *head)
{
struct fib_info *fi = container_of(head, struct fib_info, rcu);
struct dst_metrics *m;
change_nexthops(fi) {
if (nexthop_nh->nh_dev)
dev_put(nexthop_nh->nh_dev);
lwtstate_put(nexthop_nh->nh_lwtstate);
free_nh_exceptions(nexthop_nh);
rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
rt_fibinfo_free(&nexthop_nh->nh_rth_input);
} endfor_nexthops(fi);
m = fi->fib_metrics;
if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
kfree(m);
kfree(fi);
}
void free_fib_info(struct fib_info *fi)
{
if (fi->fib_dead == 0) {
pr_warn("Freeing alive fib_info %p\n", fi);
return;
}
fib_info_cnt--;
#ifdef CONFIG_IP_ROUTE_CLASSID
change_nexthops(fi) {
if (nexthop_nh->nh_tclassid)
fi->fib_net->ipv4.fib_num_tclassid_users--;
} endfor_nexthops(fi);
#endif
call_rcu(&fi->rcu, free_fib_info_rcu);
}
EXPORT_SYMBOL_GPL(free_fib_info);
void fib_release_info(struct fib_info *fi)
{
spin_lock_bh(&fib_info_lock);
if (fi && --fi->fib_treeref == 0) {
hlist_del(&fi->fib_hash);
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
change_nexthops(fi) {
if (!nexthop_nh->nh_dev)
continue;
hlist_del(&nexthop_nh->nh_hash);
} endfor_nexthops(fi)
fi->fib_dead = 1;
fib_info_put(fi);
}
spin_unlock_bh(&fib_info_lock);
}
static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
{
const struct fib_nh *onh = ofi->fib_nh;
for_nexthops(fi) {
if (nh->nh_oif != onh->nh_oif ||
nh->nh_gw != onh->nh_gw ||
nh->nh_scope != onh->nh_scope ||
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->nh_weight != onh->nh_weight ||
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid != onh->nh_tclassid ||
#endif
lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
return -1;
onh++;
} endfor_nexthops(fi);
return 0;
}
static inline unsigned int fib_devindex_hashfn(unsigned int val)
{
unsigned int mask = DEVINDEX_HASHSIZE - 1;
return (val ^
(val >> DEVINDEX_HASHBITS) ^
(val >> (DEVINDEX_HASHBITS * 2))) & mask;
}
static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
{
unsigned int mask = (fib_info_hash_size - 1);
unsigned int val = fi->fib_nhs;
val ^= (fi->fib_protocol << 8) | fi->fib_scope;
val ^= (__force u32)fi->fib_prefsrc;
val ^= fi->fib_priority;
for_nexthops(fi) {
val ^= fib_devindex_hashfn(nh->nh_oif);
} endfor_nexthops(fi)
return (val ^ (val >> 7) ^ (val >> 12)) & mask;
}
static struct fib_info *fib_find_info(const struct fib_info *nfi)
{
struct hlist_head *head;
struct fib_info *fi;
unsigned int hash;
hash = fib_info_hashfn(nfi);
head = &fib_info_hash[hash];
hlist_for_each_entry(fi, head, fib_hash) {
if (!net_eq(fi->fib_net, nfi->fib_net))
continue;
if (fi->fib_nhs != nfi->fib_nhs)
continue;
if (nfi->fib_protocol == fi->fib_protocol &&
nfi->fib_scope == fi->fib_scope &&
nfi->fib_prefsrc == fi->fib_prefsrc &&
nfi->fib_priority == fi->fib_priority &&
nfi->fib_type == fi->fib_type &&
memcmp(nfi->fib_metrics, fi->fib_metrics,
sizeof(u32) * RTAX_MAX) == 0 &&
!((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
(nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
return fi;
}
return NULL;
}
/* Check, that the gateway is already configured.
* Used only by redirect accept routine.
*/
int ip_fib_check_default(__be32 gw, struct net_device *dev)
{
struct hlist_head *head;
struct fib_nh *nh;
unsigned int hash;
spin_lock(&fib_info_lock);
hash = fib_devindex_hashfn(dev->ifindex);
head = &fib_info_devhash[hash];
hlist_for_each_entry(nh, head, nh_hash) {
if (nh->nh_dev == dev &&
nh->nh_gw == gw &&
!(nh->nh_flags & RTNH_F_DEAD)) {
spin_unlock(&fib_info_lock);
return 0;
}
}
spin_unlock(&fib_info_lock);
return -1;
}
static inline size_t fib_nlmsg_size(struct fib_info *fi)
{
size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
+ nla_total_size(4) /* RTA_TABLE */
+ nla_total_size(4) /* RTA_DST */
+ nla_total_size(4) /* RTA_PRIORITY */
+ nla_total_size(4) /* RTA_PREFSRC */
+ nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
/* space for nested metrics */
payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
if (fi->fib_nhs) {
size_t nh_encapsize = 0;
/* Also handles the special case fib_nhs == 1 */
/* each nexthop is packed in an attribute */
size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
/* may contain flow and gateway attribute */
nhsize += 2 * nla_total_size(4);
/* grab encap info */
for_nexthops(fi) {
if (nh->nh_lwtstate) {
/* RTA_ENCAP_TYPE */
nh_encapsize += lwtunnel_get_encap_size(
nh->nh_lwtstate);
/* RTA_ENCAP */
nh_encapsize += nla_total_size(2);
}
} endfor_nexthops(fi);
/* all nexthops are packed in a nested attribute */
payload += nla_total_size((fi->fib_nhs * nhsize) +
nh_encapsize);
}
return payload;
}
void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
int dst_len, u32 tb_id, const struct nl_info *info,
unsigned int nlm_flags)
{
struct sk_buff *skb;
u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
int err = -ENOBUFS;
skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
if (!skb)
goto errout;
err = fib_dump_info(skb, info->portid, seq, event, tb_id,
fa->fa_type, key, dst_len,
fa->fa_tos, fa->fa_info, nlm_flags);
if (err < 0) {
/* -EMSGSIZE implies BUG in fib_nlmsg_size() */
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto errout;
}
rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
info->nlh, GFP_KERNEL);
return;
errout:
if (err < 0)
rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
}
static int fib_detect_death(struct fib_info *fi, int order,
struct fib_info **last_resort, int *last_idx,
int dflt)
{
struct neighbour *n;
int state = NUD_NONE;
n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
if (n) {
state = n->nud_state;
neigh_release(n);
} else {
return 0;
}
if (state == NUD_REACHABLE)
return 0;
if ((state & NUD_VALID) && order != dflt)
return 0;
if ((state & NUD_VALID) ||
(*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
*last_resort = fi;
*last_idx = order;
}
return 1;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
{
int nhs = 0;
while (rtnh_ok(rtnh, remaining)) {
nhs++;
rtnh = rtnh_next(rtnh, &remaining);
}
/* leftover implies invalid nexthop configuration, discard it */
return remaining > 0 ? 0 : nhs;
}
static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
int remaining, struct fib_config *cfg)
{
int ret;
change_nexthops(fi) {
int attrlen;
if (!rtnh_ok(rtnh, remaining))
return -EINVAL;
if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
return -EINVAL;
nexthop_nh->nh_flags =
(cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
#ifdef CONFIG_IP_ROUTE_CLASSID
nla = nla_find(attrs, attrlen, RTA_FLOW);
nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
if (nexthop_nh->nh_tclassid)
fi->fib_net->ipv4.fib_num_tclassid_users++;
#endif
nla = nla_find(attrs, attrlen, RTA_ENCAP);
if (nla) {
struct lwtunnel_state *lwtstate;
struct nlattr *nla_entype;
nla_entype = nla_find(attrs, attrlen,
RTA_ENCAP_TYPE);
if (!nla_entype)
goto err_inval;
ret = lwtunnel_build_state(nla_get_u16(
nla_entype),
nla, AF_INET, cfg,
&lwtstate);
if (ret)
goto errout;
nexthop_nh->nh_lwtstate =
lwtstate_get(lwtstate);
}
}
rtnh = rtnh_next(rtnh, &remaining);
} endfor_nexthops(fi);
return 0;
err_inval:
ret = -EINVAL;
errout:
return ret;
}
static void fib_rebalance(struct fib_info *fi)
{
int total;
int w;
struct in_device *in_dev;
if (fi->fib_nhs < 2)
return;
total = 0;
for_nexthops(fi) {
if (nh->nh_flags & RTNH_F_DEAD)
continue;
in_dev = __in_dev_get_rtnl(nh->nh_dev);
if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
nh->nh_flags & RTNH_F_LINKDOWN)
continue;
total += nh->nh_weight;
} endfor_nexthops(fi);
w = 0;
change_nexthops(fi) {
int upper_bound;
in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
upper_bound = -1;
} else if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
upper_bound = -1;
} else {
w += nexthop_nh->nh_weight;
upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
total) - 1;
}
atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
} endfor_nexthops(fi);
}
static inline void fib_add_weight(struct fib_info *fi,
const struct fib_nh *nh)
{
fi->fib_weight += nh->nh_weight;
}
#else /* CONFIG_IP_ROUTE_MULTIPATH */
#define fib_rebalance(fi) do { } while (0)
#define fib_add_weight(fi, nh) do { } while (0)
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
static int fib_encap_match(u16 encap_type,
struct nlattr *encap,
const struct fib_nh *nh,
const struct fib_config *cfg)
{
struct lwtunnel_state *lwtstate;
int ret, result = 0;
if (encap_type == LWTUNNEL_ENCAP_NONE)
return 0;
ret = lwtunnel_build_state(encap_type, encap,
AF_INET, cfg, &lwtstate);
if (!ret) {
result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
lwtstate_free(lwtstate);
}
return result;
}
int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH
struct rtnexthop *rtnh;
int remaining;
#endif
if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
return 1;
if (cfg->fc_oif || cfg->fc_gw) {
if (cfg->fc_encap) {
if (fib_encap_match(cfg->fc_encap_type,
cfg->fc_encap, fi->fib_nh, cfg))
return 1;
}
if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
(!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
return 0;
return 1;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (!cfg->fc_mp)
return 0;
rtnh = cfg->fc_mp;
remaining = cfg->fc_mp_len;
for_nexthops(fi) {
int attrlen;
if (!rtnh_ok(rtnh, remaining))
return -EINVAL;
if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
return 1;
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
if (nla && nla_get_in_addr(nla) != nh->nh_gw)
return 1;
#ifdef CONFIG_IP_ROUTE_CLASSID
nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nla && nla_get_u32(nla) != nh->nh_tclassid)
return 1;
#endif
}
rtnh = rtnh_next(rtnh, &remaining);
} endfor_nexthops(fi);
#endif
return 0;
}
/*
* Picture
* -------
*
* Semantics of nexthop is very messy by historical reasons.
* We have to take into account, that:
* a) gateway can be actually local interface address,
* so that gatewayed route is direct.
* b) gateway must be on-link address, possibly
* described not by an ifaddr, but also by a direct route.
* c) If both gateway and interface are specified, they should not
* contradict.
* d) If we use tunnel routes, gateway could be not on-link.
*
* Attempt to reconcile all of these (alas, self-contradictory) conditions
* results in pretty ugly and hairy code with obscure logic.
*
* I chose to generalized it instead, so that the size
* of code does not increase practically, but it becomes
* much more general.
* Every prefix is assigned a "scope" value: "host" is local address,
* "link" is direct route,
* [ ... "site" ... "interior" ... ]
* and "universe" is true gateway route with global meaning.
*
* Every prefix refers to a set of "nexthop"s (gw, oif),
* where gw must have narrower scope. This recursion stops
* when gw has LOCAL scope or if "nexthop" is declared ONLINK,
* which means that gw is forced to be on link.
*
* Code is still hairy, but now it is apparently logically
* consistent and very flexible. F.e. as by-product it allows
* to co-exists in peace independent exterior and interior
* routing processes.
*
* Normally it looks as following.
*
* {universe prefix} -> (gw, oif) [scope link]
* |
* |-> {link prefix} -> (gw, oif) [scope local]
* |
* |-> {local prefix} (terminal node)
*/
static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
struct fib_nh *nh)
{
int err = 0;
struct net *net;
struct net_device *dev;
net = cfg->fc_nlinfo.nl_net;
if (nh->nh_gw) {
struct fib_result res;
if (nh->nh_flags & RTNH_F_ONLINK) {
unsigned int addr_type;
if (cfg->fc_scope >= RT_SCOPE_LINK)
return -EINVAL;
dev = __dev_get_by_index(net, nh->nh_oif);
if (!dev)
return -ENODEV;
if (!(dev->flags & IFF_UP))
return -ENETDOWN;
addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
if (addr_type != RTN_UNICAST)
return -EINVAL;
if (!netif_carrier_ok(dev))
nh->nh_flags |= RTNH_F_LINKDOWN;
nh->nh_dev = dev;
dev_hold(dev);
nh->nh_scope = RT_SCOPE_LINK;
return 0;
}
rcu_read_lock();
{
struct fib_table *tbl = NULL;
struct flowi4 fl4 = {
.daddr = nh->nh_gw,
.flowi4_scope = cfg->fc_scope + 1,
.flowi4_oif = nh->nh_oif,
.flowi4_iif = LOOPBACK_IFINDEX,
};
/* It is not necessary, but requires a bit of thinking */
if (fl4.flowi4_scope < RT_SCOPE_LINK)
fl4.flowi4_scope = RT_SCOPE_LINK;
if (cfg->fc_table)
tbl = fib_get_table(net, cfg->fc_table);
if (tbl)
err = fib_table_lookup(tbl, &fl4, &res,
FIB_LOOKUP_IGNORE_LINKSTATE |
FIB_LOOKUP_NOREF);
/* on error or if no table given do full lookup. This
* is needed for example when nexthops are in the local
* table rather than the given table
*/
if (!tbl || err) {
err = fib_lookup(net, &fl4, &res,
FIB_LOOKUP_IGNORE_LINKSTATE);
}
if (err) {
rcu_read_unlock();
return err;
}
}
err = -EINVAL;
if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
goto out;
nh->nh_scope = res.scope;
nh->nh_oif = FIB_RES_OIF(res);
nh->nh_dev = dev = FIB_RES_DEV(res);
if (!dev)
goto out;
dev_hold(dev);
if (!netif_carrier_ok(dev))
nh->nh_flags |= RTNH_F_LINKDOWN;
err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
} else {
struct in_device *in_dev;
if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
return -EINVAL;
rcu_read_lock();
err = -ENODEV;
in_dev = inetdev_by_index(net, nh->nh_oif);
if (!in_dev)
goto out;
err = -ENETDOWN;
if (!(in_dev->dev->flags & IFF_UP))
goto out;
nh->nh_dev = in_dev->dev;
dev_hold(nh->nh_dev);
nh->nh_scope = RT_SCOPE_HOST;
if (!netif_carrier_ok(nh->nh_dev))
nh->nh_flags |= RTNH_F_LINKDOWN;
err = 0;
}
out:
rcu_read_unlock();
return err;
}
static inline unsigned int fib_laddr_hashfn(__be32 val)
{
unsigned int mask = (fib_info_hash_size - 1);
return ((__force u32)val ^
((__force u32)val >> 7) ^
((__force u32)val >> 14)) & mask;
}
static struct hlist_head *fib_info_hash_alloc(int bytes)
{
if (bytes <= PAGE_SIZE)
return kzalloc(bytes, GFP_KERNEL);
else
return (struct hlist_head *)
__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(bytes));
}
static void fib_info_hash_free(struct hlist_head *hash, int bytes)
{
if (!hash)
return;
if (bytes <= PAGE_SIZE)
kfree(hash);
else
free_pages((unsigned long) hash, get_order(bytes));
}
static void fib_info_hash_move(struct hlist_head *new_info_hash,
struct hlist_head *new_laddrhash,
unsigned int new_size)
{
struct hlist_head *old_info_hash, *old_laddrhash;
unsigned int old_size = fib_info_hash_size;
unsigned int i, bytes;
spin_lock_bh(&fib_info_lock);
old_info_hash = fib_info_hash;
old_laddrhash = fib_info_laddrhash;
fib_info_hash_size = new_size;
for (i = 0; i < old_size; i++) {
struct hlist_head *head = &fib_info_hash[i];
struct hlist_node *n;
struct fib_info *fi;
hlist_for_each_entry_safe(fi, n, head, fib_hash) {
struct hlist_head *dest;
unsigned int new_hash;
new_hash = fib_info_hashfn(fi);
dest = &new_info_hash[new_hash];
hlist_add_head(&fi->fib_hash, dest);
}
}
fib_info_hash = new_info_hash;
for (i = 0; i < old_size; i++) {
struct hlist_head *lhead = &fib_info_laddrhash[i];
struct hlist_node *n;
struct fib_info *fi;
hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
struct hlist_head *ldest;
unsigned int new_hash;
new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
ldest = &new_laddrhash[new_hash];
hlist_add_head(&fi->fib_lhash, ldest);
}
}
fib_info_laddrhash = new_laddrhash;
spin_unlock_bh(&fib_info_lock);
bytes = old_size * sizeof(struct hlist_head *);
fib_info_hash_free(old_info_hash, bytes);
fib_info_hash_free(old_laddrhash, bytes);
}
__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
{
nh->nh_saddr = inet_select_addr(nh->nh_dev,
nh->nh_gw,
nh->nh_parent->fib_scope);
nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
return nh->nh_saddr;
}
static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
{
if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
fib_prefsrc != cfg->fc_dst) {
u32 tb_id = cfg->fc_table;
int rc;
if (tb_id == RT_TABLE_MAIN)
tb_id = RT_TABLE_LOCAL;
rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
fib_prefsrc, tb_id);
if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
fib_prefsrc, RT_TABLE_LOCAL);
}
if (rc != RTN_LOCAL)
return false;
}
return true;
}
static int
fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
{
bool ecn_ca = false;
struct nlattr *nla;
int remaining;
if (!cfg->fc_mx)
return 0;
nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
int type = nla_type(nla);
u32 val;
if (!type)
continue;
if (type > RTAX_MAX)
return -EINVAL;
if (type == RTAX_CC_ALGO) {
char tmp[TCP_CA_NAME_MAX];
nla_strlcpy(tmp, nla, sizeof(tmp));
val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
if (val == TCP_CA_UNSPEC)
return -EINVAL;
} else {
val = nla_get_u32(nla);
}
if (type == RTAX_ADVMSS && val > 65535 - 40)
val = 65535 - 40;
if (type == RTAX_MTU && val > 65535 - 15)
val = 65535 - 15;
if (type == RTAX_HOPLIMIT && val > 255)
val = 255;
if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
return -EINVAL;
fi->fib_metrics->metrics[type - 1] = val;
}
if (ecn_ca)
fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
return 0;
}
struct fib_info *fib_create_info(struct fib_config *cfg)
{
int err;
struct fib_info *fi = NULL;
struct fib_info *ofi;
int nhs = 1;
struct net *net = cfg->fc_nlinfo.nl_net;
if (cfg->fc_type > RTN_MAX)
goto err_inval;
/* Fast check to catch the most weird cases */
if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
goto err_inval;
if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
goto err_inval;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (cfg->fc_mp) {
nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
if (nhs == 0)
goto err_inval;
}
#endif
err = -ENOBUFS;
if (fib_info_cnt >= fib_info_hash_size) {
unsigned int new_size = fib_info_hash_size << 1;
struct hlist_head *new_info_hash;
struct hlist_head *new_laddrhash;
unsigned int bytes;
if (!new_size)
new_size = 16;
bytes = new_size * sizeof(struct hlist_head *);
new_info_hash = fib_info_hash_alloc(bytes);
new_laddrhash = fib_info_hash_alloc(bytes);
if (!new_info_hash || !new_laddrhash) {
fib_info_hash_free(new_info_hash, bytes);
fib_info_hash_free(new_laddrhash, bytes);
} else
fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
if (!fib_info_hash_size)
goto failure;
}
fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
if (!fi)
goto failure;
fib_info_cnt++;
if (cfg->fc_mx) {
fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
if (!fi->fib_metrics)
goto failure;
atomic_set(&fi->fib_metrics->refcnt, 1);
} else
fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
fi->fib_net = net;
fi->fib_protocol = cfg->fc_protocol;
fi->fib_scope = cfg->fc_scope;
fi->fib_flags = cfg->fc_flags;
fi->fib_priority = cfg->fc_priority;
fi->fib_prefsrc = cfg->fc_prefsrc;
fi->fib_type = cfg->fc_type;
fi->fib_tb_id = cfg->fc_table;
fi->fib_nhs = nhs;
change_nexthops(fi) {
nexthop_nh->nh_parent = fi;
nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
if (!nexthop_nh->nh_pcpu_rth_output)
goto failure;
} endfor_nexthops(fi)
err = fib_convert_metrics(fi, cfg);
if (err)
goto failure;
if (cfg->fc_mp) {
#ifdef CONFIG_IP_ROUTE_MULTIPATH
err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
if (err != 0)
goto failure;
if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
goto err_inval;
if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
goto err_inval;
#ifdef CONFIG_IP_ROUTE_CLASSID
if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
goto err_inval;
#endif
#else
goto err_inval;
#endif
} else {
struct fib_nh *nh = fi->fib_nh;
if (cfg->fc_encap) {
struct lwtunnel_state *lwtstate;
if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
goto err_inval;
err = lwtunnel_build_state(cfg->fc_encap_type,
cfg->fc_encap, AF_INET, cfg,
&lwtstate);
if (err)
goto failure;
nh->nh_lwtstate = lwtstate_get(lwtstate);
}
nh->nh_oif = cfg->fc_oif;
nh->nh_gw = cfg->fc_gw;
nh->nh_flags = cfg->fc_flags;
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid = cfg->fc_flow;
if (nh->nh_tclassid)
fi->fib_net->ipv4.fib_num_tclassid_users++;
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->nh_weight = 1;
#endif
}
if (fib_props[cfg->fc_type].error) {
if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
goto err_inval;
goto link_it;
} else {
switch (cfg->fc_type) {
case RTN_UNICAST:
case RTN_LOCAL:
case RTN_BROADCAST:
case RTN_ANYCAST:
case RTN_MULTICAST:
break;
default:
goto err_inval;
}
}
if (cfg->fc_scope > RT_SCOPE_HOST)
goto err_inval;
if (cfg->fc_scope == RT_SCOPE_HOST) {
struct fib_nh *nh = fi->fib_nh;
/* Local address is added. */
if (nhs != 1 || nh->nh_gw)
goto err_inval;
nh->nh_scope = RT_SCOPE_NOWHERE;
nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
err = -ENODEV;
if (!nh->nh_dev)
goto failure;
} else {
int linkdown = 0;
change_nexthops(fi) {
err = fib_check_nh(cfg, fi, nexthop_nh);
if (err != 0)
goto failure;
if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
linkdown++;
} endfor_nexthops(fi)
if (linkdown == fi->fib_nhs)
fi->fib_flags |= RTNH_F_LINKDOWN;
}
if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
goto err_inval;
change_nexthops(fi) {
fib_info_update_nh_saddr(net, nexthop_nh);
fib_add_weight(fi, nexthop_nh);
} endfor_nexthops(fi)
fib_rebalance(fi);
link_it:
ofi = fib_find_info(fi);
if (ofi) {
fi->fib_dead = 1;
free_fib_info(fi);
ofi->fib_treeref++;
return ofi;
}
fi->fib_treeref++;
atomic_inc(&fi->fib_clntref);
spin_lock_bh(&fib_info_lock);
hlist_add_head(&fi->fib_hash,
&fib_info_hash[fib_info_hashfn(fi)]);
if (fi->fib_prefsrc) {
struct hlist_head *head;
head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
hlist_add_head(&fi->fib_lhash, head);
}
change_nexthops(fi) {
struct hlist_head *head;
unsigned int hash;
if (!nexthop_nh->nh_dev)
continue;
hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
head = &fib_info_devhash[hash];
hlist_add_head(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
spin_unlock_bh(&fib_info_lock);
return fi;
err_inval:
err = -EINVAL;
failure:
if (fi) {
fi->fib_dead = 1;
free_fib_info(fi);
}
return ERR_PTR(err);
}
int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
struct fib_info *fi, unsigned int flags)
{
struct nlmsghdr *nlh;
struct rtmsg *rtm;
nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
if (!nlh)
return -EMSGSIZE;
rtm = nlmsg_data(nlh);
rtm->rtm_family = AF_INET;
rtm->rtm_dst_len = dst_len;
rtm->rtm_src_len = 0;
rtm->rtm_tos = tos;
if (tb_id < 256)
rtm->rtm_table = tb_id;
else
rtm->rtm_table = RT_TABLE_COMPAT;
if (nla_put_u32(skb, RTA_TABLE, tb_id))
goto nla_put_failure;
rtm->rtm_type = type;
rtm->rtm_flags = fi->fib_flags;
rtm->rtm_scope = fi->fib_scope;
rtm->rtm_protocol = fi->fib_protocol;
if (rtm->rtm_dst_len &&
nla_put_in_addr(skb, RTA_DST, dst))
goto nla_put_failure;
if (fi->fib_priority &&
nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
goto nla_put_failure;
if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
goto nla_put_failure;
if (fi->fib_prefsrc &&
nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
goto nla_put_failure;
if (fi->fib_nhs == 1) {
struct in_device *in_dev;
if (fi->fib_nh->nh_gw &&
nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
goto nla_put_failure;
if (fi->fib_nh->nh_oif &&
nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
goto nla_put_failure;
if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
rtm->rtm_flags |= RTNH_F_DEAD;
}
#ifdef CONFIG_IP_ROUTE_CLASSID
if (fi->fib_nh[0].nh_tclassid &&
nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
goto nla_put_failure;
#endif
if (fi->fib_nh->nh_lwtstate &&
lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
goto nla_put_failure;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (fi->fib_nhs > 1) {
struct rtnexthop *rtnh;
struct nlattr *mp;
mp = nla_nest_start(skb, RTA_MULTIPATH);
if (!mp)
goto nla_put_failure;
for_nexthops(fi) {
struct in_device *in_dev;
rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
if (!rtnh)
goto nla_put_failure;
rtnh->rtnh_flags = nh->nh_flags & 0xFF;
if (nh->nh_flags & RTNH_F_LINKDOWN) {
in_dev = __in_dev_get_rtnl(nh->nh_dev);
if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
rtnh->rtnh_flags |= RTNH_F_DEAD;
}
rtnh->rtnh_hops = nh->nh_weight - 1;
rtnh->rtnh_ifindex = nh->nh_oif;
if (nh->nh_gw &&
nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
goto nla_put_failure;
#ifdef CONFIG_IP_ROUTE_CLASSID
if (nh->nh_tclassid &&
nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
goto nla_put_failure;
#endif
if (nh->nh_lwtstate &&
lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
goto nla_put_failure;
/* length of rtnetlink header + attributes */
rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
} endfor_nexthops(fi);
nla_nest_end(skb, mp);
}
#endif
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
nlmsg_cancel(skb, nlh);
return -EMSGSIZE;
}
/*
* Update FIB if:
* - local address disappeared -> we must delete all the entries
* referring to it.
* - device went down -> we must shutdown all nexthops going via it.
*/
int fib_sync_down_addr(struct net_device *dev, __be32 local)
{
int ret = 0;
unsigned int hash = fib_laddr_hashfn(local);
struct hlist_head *head = &fib_info_laddrhash[hash];
struct net *net = dev_net(dev);
int tb_id = l3mdev_fib_table(dev);
struct fib_info *fi;
if (!fib_info_laddrhash || local == 0)
return 0;
hlist_for_each_entry(fi, head, fib_lhash) {
if (!net_eq(fi->fib_net, net) ||
fi->fib_tb_id != tb_id)
continue;
if (fi->fib_prefsrc == local) {
fi->fib_flags |= RTNH_F_DEAD;
ret++;
}
}
return ret;
}
static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
enum fib_event_type event_type)
{
struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
struct fib_nh_notifier_info info = {
.fib_nh = fib_nh,
};
switch (event_type) {
case FIB_EVENT_NH_ADD:
if (fib_nh->nh_flags & RTNH_F_DEAD)
break;
if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
fib_nh->nh_flags & RTNH_F_LINKDOWN)
break;
return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type,
&info.info);
case FIB_EVENT_NH_DEL:
if ((IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
(fib_nh->nh_flags & RTNH_F_DEAD))
return call_fib_notifiers(dev_net(fib_nh->nh_dev),
event_type, &info.info);
default:
break;
}
return NOTIFY_DONE;
}
/* Event force Flags Description
* NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
* NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
* NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
* NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
*/
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
{
int ret = 0;
int scope = RT_SCOPE_NOWHERE;
struct fib_info *prev_fi = NULL;
unsigned int hash = fib_devindex_hashfn(dev->ifindex);
struct hlist_head *head = &fib_info_devhash[hash];
struct fib_nh *nh;
if (force)
scope = -1;
hlist_for_each_entry(nh, head, nh_hash) {
struct fib_info *fi = nh->nh_parent;
int dead;
BUG_ON(!fi->fib_nhs);
if (nh->nh_dev != dev || fi == prev_fi)
continue;
prev_fi = fi;
dead = 0;
change_nexthops(fi) {
if (nexthop_nh->nh_flags & RTNH_F_DEAD)
dead++;
else if (nexthop_nh->nh_dev == dev &&
nexthop_nh->nh_scope != scope) {
switch (event) {
case NETDEV_DOWN:
case NETDEV_UNREGISTER:
nexthop_nh->nh_flags |= RTNH_F_DEAD;
/* fall through */
case NETDEV_CHANGE:
nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
break;
}
call_fib_nh_notifiers(nexthop_nh,
FIB_EVENT_NH_DEL);
dead++;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (event == NETDEV_UNREGISTER &&
nexthop_nh->nh_dev == dev) {
dead = fi->fib_nhs;
break;
}
#endif
} endfor_nexthops(fi)
if (dead == fi->fib_nhs) {
switch (event) {
case NETDEV_DOWN:
case NETDEV_UNREGISTER:
fi->fib_flags |= RTNH_F_DEAD;
/* fall through */
case NETDEV_CHANGE:
fi->fib_flags |= RTNH_F_LINKDOWN;
break;
}
ret++;
}
fib_rebalance(fi);
}
return ret;
}
/* Must be invoked inside of an RCU protected region. */
static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
{
struct fib_info *fi = NULL, *last_resort = NULL;
struct hlist_head *fa_head = res->fa_head;
struct fib_table *tb = res->table;
u8 slen = 32 - res->prefixlen;
int order = -1, last_idx = -1;
struct fib_alias *fa, *fa1 = NULL;
u32 last_prio = res->fi->fib_priority;
u8 last_tos = 0;
hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
struct fib_info *next_fi = fa->fa_info;
if (fa->fa_slen != slen)
continue;
if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
continue;
if (fa->tb_id != tb->tb_id)
continue;
if (next_fi->fib_priority > last_prio &&
fa->fa_tos == last_tos) {
if (last_tos)
continue;
break;
}
if (next_fi->fib_flags & RTNH_F_DEAD)
continue;
last_tos = fa->fa_tos;
last_prio = next_fi->fib_priority;
if (next_fi->fib_scope != res->scope ||
fa->fa_type != RTN_UNICAST)
continue;
if (!next_fi->fib_nh[0].nh_gw ||
next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
continue;
fib_alias_accessed(fa);
if (!fi) {
if (next_fi != res->fi)
break;
fa1 = fa;
} else if (!fib_detect_death(fi, order, &last_resort,
&last_idx, fa1->fa_default)) {
fib_result_assign(res, fi);
fa1->fa_default = order;
goto out;
}
fi = next_fi;
order++;
}
if (order <= 0 || !fi) {
if (fa1)
fa1->fa_default = -1;
goto out;
}
if (!fib_detect_death(fi, order, &last_resort, &last_idx,
fa1->fa_default)) {
fib_result_assign(res, fi);
fa1->fa_default = order;
goto out;
}
if (last_idx >= 0)
fib_result_assign(res, last_resort);
fa1->fa_default = last_idx;
out:
return;
}
/*
* Dead device goes up. We wake up dead nexthops.
* It takes sense only on multipath routes.
*/
int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
{
struct fib_info *prev_fi;
unsigned int hash;
struct hlist_head *head;
struct fib_nh *nh;
int ret;
if (!(dev->flags & IFF_UP))
return 0;
if (nh_flags & RTNH_F_DEAD) {
unsigned int flags = dev_get_flags(dev);
if (flags & (IFF_RUNNING | IFF_LOWER_UP))
nh_flags |= RTNH_F_LINKDOWN;
}
prev_fi = NULL;
hash = fib_devindex_hashfn(dev->ifindex);
head = &fib_info_devhash[hash];
ret = 0;
hlist_for_each_entry(nh, head, nh_hash) {
struct fib_info *fi = nh->nh_parent;
int alive;
BUG_ON(!fi->fib_nhs);
if (nh->nh_dev != dev || fi == prev_fi)
continue;
prev_fi = fi;
alive = 0;
change_nexthops(fi) {
if (!(nexthop_nh->nh_flags & nh_flags)) {
alive++;
continue;
}
if (!nexthop_nh->nh_dev ||
!(nexthop_nh->nh_dev->flags & IFF_UP))
continue;
if (nexthop_nh->nh_dev != dev ||
!__in_dev_get_rtnl(dev))
continue;
alive++;
nexthop_nh->nh_flags &= ~nh_flags;
call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
} endfor_nexthops(fi)
if (alive > 0) {
fi->fib_flags &= ~nh_flags;
ret++;
}
fib_rebalance(fi);
}
return ret;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
static bool fib_good_nh(const struct fib_nh *nh)
{
int state = NUD_REACHABLE;
if (nh->nh_scope == RT_SCOPE_LINK) {
struct neighbour *n;
rcu_read_lock_bh();
n = __ipv4_neigh_lookup_noref(nh->nh_dev,
(__force u32)nh->nh_gw);
if (n)
state = n->nud_state;
rcu_read_unlock_bh();
}
return !!(state & NUD_VALID);
}
void fib_select_multipath(struct fib_result *res, int hash)
{
struct fib_info *fi = res->fi;
struct net *net = fi->fib_net;
bool first = false;
for_nexthops(fi) {
if (hash > atomic_read(&nh->nh_upper_bound))
continue;
if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
fib_good_nh(nh)) {
res->nh_sel = nhsel;
return;
}
if (!first) {
res->nh_sel = nhsel;
first = true;
}
} endfor_nexthops(fi);
}
#endif
void fib_select_path(struct net *net, struct fib_result *res,
struct flowi4 *fl4, const struct sk_buff *skb)
{
bool oif_check;
oif_check = (fl4->flowi4_oif == 0 ||
fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
if (res->fi->fib_nhs > 1 && oif_check) {
int h = fib_multipath_hash(res->fi, fl4, skb);
fib_select_multipath(res, h);
}
else
#endif
if (!res->prefixlen &&
res->table->tb_num_default > 1 &&
res->type == RTN_UNICAST && oif_check)
fib_select_default(fl4, res);
if (!fl4->saddr)
fl4->saddr = FIB_RES_PREFSRC(net, *res);
}
EXPORT_SYMBOL_GPL(fib_select_path);
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