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fib_semantics.c
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fib_semantics.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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, <[email protected]>
*/
#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 <linux/netlink.h>
#include <linux/hash.h>
#include <linux/nospec.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/ip6_fib.h>
#include <net/nexthop.h>
#include <net/netlink.h>
#include <net/rtnh.h>
#include <net/lwtunnel.h>
#include <net/fib_notifier.h>
#include <net/addrconf.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];
/* for_nexthops and change_nexthops only used when nexthop object
* is not set in a fib_info. The logic within can reference fib_nh.
*/
#ifdef CONFIG_IP_ROUTE_MULTIPATH
#define for_nexthops(fi) { \
int nhsel; const struct fib_nh *nh; \
for (nhsel = 0, nh = (fi)->fib_nh; \
nhsel < fib_info_num_path((fi)); \
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 < fib_info_num_path((fi)); \
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,
},
[RTN_POLICY_FAILED] = {
.error = -EACCES,
.scope = RT_SCOPE_UNIVERSE,
},
};
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_dev_put(&rt->dst);
dst_release_immediate(&rt->dst);
}
static void free_nh_exceptions(struct fib_nh_common *nhc)
{
struct fnhe_hash_bucket *hash;
int i;
hash = rcu_dereference_protected(nhc->nhc_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_dev_put(&rt->dst);
dst_release_immediate(&rt->dst);
}
}
free_percpu(rtp);
}
void fib_nh_common_release(struct fib_nh_common *nhc)
{
dev_put(nhc->nhc_dev);
lwtstate_put(nhc->nhc_lwtstate);
rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
rt_fibinfo_free(&nhc->nhc_rth_input);
free_nh_exceptions(nhc);
}
EXPORT_SYMBOL_GPL(fib_nh_common_release);
void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
{
#ifdef CONFIG_IP_ROUTE_CLASSID
if (fib_nh->nh_tclassid)
atomic_dec(&net->ipv4.fib_num_tclassid_users);
#endif
fib_nh_common_release(&fib_nh->nh_common);
}
/* 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);
if (fi->nh) {
nexthop_put(fi->nh);
} else {
change_nexthops(fi) {
fib_nh_release(fi->fib_net, nexthop_nh);
} endfor_nexthops(fi);
}
ip_fib_metrics_put(fi->fib_metrics);
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;
}
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 && refcount_dec_and_test(&fi->fib_treeref)) {
hlist_del(&fi->fib_hash);
/* Paired with READ_ONCE() in fib_create_info(). */
WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
if (fi->nh) {
list_del(&fi->nh_list);
} else {
change_nexthops(fi) {
if (!nexthop_nh->fib_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(struct fib_info *fi, struct fib_info *ofi)
{
const struct fib_nh *onh;
if (fi->nh || ofi->nh)
return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
if (ofi->fib_nhs == 0)
return 0;
for_nexthops(fi) {
onh = fib_info_nh(ofi, nhsel);
if (nh->fib_nh_oif != onh->fib_nh_oif ||
nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
nh->fib_nh_scope != onh->fib_nh_scope ||
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->fib_nh_weight != onh->fib_nh_weight ||
#endif
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid != onh->nh_tclassid ||
#endif
lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
return -1;
if (nh->fib_nh_gw_family == AF_INET &&
nh->fib_nh_gw4 != onh->fib_nh_gw4)
return -1;
if (nh->fib_nh_gw_family == AF_INET6 &&
ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
return -1;
} endfor_nexthops(fi);
return 0;
}
static inline unsigned int fib_devindex_hashfn(unsigned int val)
{
return hash_32(val, DEVINDEX_HASHBITS);
}
static struct hlist_head *
fib_info_devhash_bucket(const struct net_device *dev)
{
u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
return &fib_info_devhash[fib_devindex_hashfn(val)];
}
static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
u32 prefsrc, u32 priority)
{
unsigned int val = init_val;
val ^= (protocol << 8) | scope;
val ^= prefsrc;
val ^= priority;
return val;
}
static unsigned int fib_info_hashfn_result(unsigned int val)
{
unsigned int mask = (fib_info_hash_size - 1);
return (val ^ (val >> 7) ^ (val >> 12)) & mask;
}
static inline unsigned int fib_info_hashfn(struct fib_info *fi)
{
unsigned int val;
val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
fi->fib_scope, (__force u32)fi->fib_prefsrc,
fi->fib_priority);
if (fi->nh) {
val ^= fib_devindex_hashfn(fi->nh->id);
} else {
for_nexthops(fi) {
val ^= fib_devindex_hashfn(nh->fib_nh_oif);
} endfor_nexthops(fi)
}
return fib_info_hashfn_result(val);
}
/* no metrics, only nexthop id */
static struct fib_info *fib_find_info_nh(struct net *net,
const struct fib_config *cfg)
{
struct hlist_head *head;
struct fib_info *fi;
unsigned int hash;
hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
cfg->fc_protocol, cfg->fc_scope,
(__force u32)cfg->fc_prefsrc,
cfg->fc_priority);
hash = fib_info_hashfn_result(hash);
head = &fib_info_hash[hash];
hlist_for_each_entry(fi, head, fib_hash) {
if (!net_eq(fi->fib_net, net))
continue;
if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
continue;
if (cfg->fc_protocol == fi->fib_protocol &&
cfg->fc_scope == fi->fib_scope &&
cfg->fc_prefsrc == fi->fib_prefsrc &&
cfg->fc_priority == fi->fib_priority &&
cfg->fc_type == fi->fib_type &&
cfg->fc_table == fi->fib_tb_id &&
!((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
return fi;
}
return NULL;
}
static struct fib_info *fib_find_info(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 &&
nfi->fib_tb_id == fi->fib_tb_id &&
memcmp(nfi->fib_metrics, fi->fib_metrics,
sizeof(u32) * RTAX_MAX) == 0 &&
!((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
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;
spin_lock(&fib_info_lock);
head = fib_info_devhash_bucket(dev);
hlist_for_each_entry(nh, head, nh_hash) {
if (nh->fib_nh_dev == dev &&
nh->fib_nh_gw4 == gw &&
!(nh->fib_nh_flags & RTNH_F_DEAD)) {
spin_unlock(&fib_info_lock);
return 0;
}
}
spin_unlock(&fib_info_lock);
return -1;
}
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 */
unsigned int nhs = fib_info_num_path(fi);
/* space for nested metrics */
payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
if (fi->nh)
payload += nla_total_size(4); /* RTA_NH_ID */
if (nhs) {
size_t nh_encapsize = 0;
/* Also handles the special case nhs == 1 */
/* each nexthop is packed in an attribute */
size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
unsigned int i;
/* may contain flow and gateway attribute */
nhsize += 2 * nla_total_size(4);
/* grab encap info */
for (i = 0; i < fib_info_num_path(fi); i++) {
struct fib_nh_common *nhc = fib_info_nhc(fi, i);
if (nhc->nhc_lwtstate) {
/* RTA_ENCAP_TYPE */
nh_encapsize += lwtunnel_get_encap_size(
nhc->nhc_lwtstate);
/* RTA_ENCAP */
nh_encapsize += nla_total_size(2);
}
}
/* all nexthops are packed in a nested attribute */
payload += nla_total_size((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 fib_rt_info fri;
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;
fri.fi = fa->fa_info;
fri.tb_id = tb_id;
fri.dst = key;
fri.dst_len = dst_len;
fri.tos = fa->fa_tos;
fri.type = fa->fa_type;
fri.offload = READ_ONCE(fa->offload);
fri.trap = READ_ONCE(fa->trap);
fri.offload_failed = READ_ONCE(fa->offload_failed);
err = fib_dump_info(skb, info->portid, seq, event, &fri, 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)
{
const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
struct neighbour *n;
int state = NUD_NONE;
if (likely(nhc->nhc_gw_family == AF_INET))
n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
else if (nhc->nhc_gw_family == AF_INET6)
n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
nhc->nhc_dev);
else
n = NULL;
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;
}
int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
struct nlattr *encap, u16 encap_type,
void *cfg, gfp_t gfp_flags,
struct netlink_ext_ack *extack)
{
int err;
nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
gfp_flags);
if (!nhc->nhc_pcpu_rth_output)
return -ENOMEM;
if (encap) {
struct lwtunnel_state *lwtstate;
if (encap_type == LWTUNNEL_ENCAP_NONE) {
NL_SET_ERR_MSG(extack, "LWT encap type not specified");
err = -EINVAL;
goto lwt_failure;
}
err = lwtunnel_build_state(net, encap_type, encap,
nhc->nhc_family, cfg, &lwtstate,
extack);
if (err)
goto lwt_failure;
nhc->nhc_lwtstate = lwtstate_get(lwtstate);
}
return 0;
lwt_failure:
rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
nhc->nhc_pcpu_rth_output = NULL;
return err;
}
EXPORT_SYMBOL_GPL(fib_nh_common_init);
int fib_nh_init(struct net *net, struct fib_nh *nh,
struct fib_config *cfg, int nh_weight,
struct netlink_ext_ack *extack)
{
int err;
nh->fib_nh_family = AF_INET;
err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
if (err)
return err;
nh->fib_nh_oif = cfg->fc_oif;
nh->fib_nh_gw_family = cfg->fc_gw_family;
if (cfg->fc_gw_family == AF_INET)
nh->fib_nh_gw4 = cfg->fc_gw4;
else if (cfg->fc_gw_family == AF_INET6)
nh->fib_nh_gw6 = cfg->fc_gw6;
nh->fib_nh_flags = cfg->fc_flags;
#ifdef CONFIG_IP_ROUTE_CLASSID
nh->nh_tclassid = cfg->fc_flow;
if (nh->nh_tclassid)
atomic_inc(&net->ipv4.fib_num_tclassid_users);
#endif
#ifdef CONFIG_IP_ROUTE_MULTIPATH
nh->fib_nh_weight = nh_weight;
#endif
return 0;
}
#ifdef CONFIG_IP_ROUTE_MULTIPATH
static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
struct netlink_ext_ack *extack)
{
int nhs = 0;
while (rtnh_ok(rtnh, remaining)) {
nhs++;
rtnh = rtnh_next(rtnh, &remaining);
}
/* leftover implies invalid nexthop configuration, discard it */
if (remaining > 0) {
NL_SET_ERR_MSG(extack,
"Invalid nexthop configuration - extra data after nexthops");
nhs = 0;
}
return nhs;
}
static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
struct netlink_ext_ack *extack)
{
if (nla_len(nla) < sizeof(*gw)) {
NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
return -EINVAL;
}
*gw = nla_get_in_addr(nla);
return 0;
}
/* only called when fib_nh is integrated into fib_info */
static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
int remaining, struct fib_config *cfg,
struct netlink_ext_ack *extack)
{
struct net *net = fi->fib_net;
struct fib_config fib_cfg;
struct fib_nh *nh;
int ret;
change_nexthops(fi) {
int attrlen;
memset(&fib_cfg, 0, sizeof(fib_cfg));
if (!rtnh_ok(rtnh, remaining)) {
NL_SET_ERR_MSG(extack,
"Invalid nexthop configuration - extra data after nexthop");
return -EINVAL;
}
if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
NL_SET_ERR_MSG(extack,
"Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
return -EINVAL;
}
fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
fib_cfg.fc_oif = rtnh->rtnh_ifindex;
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
nlav = nla_find(attrs, attrlen, RTA_VIA);
if (nla && nlav) {
NL_SET_ERR_MSG(extack,
"Nexthop configuration can not contain both GATEWAY and VIA");
return -EINVAL;
}
if (nla) {
ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
extack);
if (ret)
goto errout;
if (fib_cfg.fc_gw4)
fib_cfg.fc_gw_family = AF_INET;
} else if (nlav) {
ret = fib_gw_from_via(&fib_cfg, nlav, extack);
if (ret)
goto errout;
}
nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nla) {
if (nla_len(nla) < sizeof(u32)) {
NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
return -EINVAL;
}
fib_cfg.fc_flow = nla_get_u32(nla);
}
fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
/* RTA_ENCAP_TYPE length checked in
* lwtunnel_valid_encap_type_attr
*/
nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
if (nla)
fib_cfg.fc_encap_type = nla_get_u16(nla);
}
ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
rtnh->rtnh_hops + 1, extack);
if (ret)
goto errout;
rtnh = rtnh_next(rtnh, &remaining);
} endfor_nexthops(fi);
ret = -EINVAL;
nh = fib_info_nh(fi, 0);
if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
NL_SET_ERR_MSG(extack,
"Nexthop device index does not match RTA_OIF");
goto errout;
}
if (cfg->fc_gw_family) {
if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
(cfg->fc_gw_family == AF_INET &&
nh->fib_nh_gw4 != cfg->fc_gw4) ||
(cfg->fc_gw_family == AF_INET6 &&
ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
NL_SET_ERR_MSG(extack,
"Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
goto errout;
}
}
#ifdef CONFIG_IP_ROUTE_CLASSID
if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
NL_SET_ERR_MSG(extack,
"Nexthop class id does not match RTA_FLOW");
goto errout;
}
#endif
ret = 0;
errout:
return ret;
}
/* only called when fib_nh is integrated into fib_info */
static void fib_rebalance(struct fib_info *fi)
{
int total;
int w;
if (fib_info_num_path(fi) < 2)
return;
total = 0;
for_nexthops(fi) {
if (nh->fib_nh_flags & RTNH_F_DEAD)
continue;
if (ip_ignore_linkdown(nh->fib_nh_dev) &&
nh->fib_nh_flags & RTNH_F_LINKDOWN)
continue;
total += nh->fib_nh_weight;
} endfor_nexthops(fi);
w = 0;
change_nexthops(fi) {
int upper_bound;
if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
upper_bound = -1;
} else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
upper_bound = -1;
} else {
w += nexthop_nh->fib_nh_weight;
upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
total) - 1;
}
atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
} endfor_nexthops(fi);
}
#else /* CONFIG_IP_ROUTE_MULTIPATH */
static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
int remaining, struct fib_config *cfg,
struct netlink_ext_ack *extack)
{
NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
return -EINVAL;
}
#define fib_rebalance(fi) do { } while (0)
#endif /* CONFIG_IP_ROUTE_MULTIPATH */
static int fib_encap_match(struct net *net, u16 encap_type,
struct nlattr *encap,
const struct fib_nh *nh,
const struct fib_config *cfg,
struct netlink_ext_ack *extack)
{
struct lwtunnel_state *lwtstate;
int ret, result = 0;
if (encap_type == LWTUNNEL_ENCAP_NONE)
return 0;
ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
cfg, &lwtstate, extack);
if (!ret) {
result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
lwtstate_free(lwtstate);
}
return result;
}
int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
struct netlink_ext_ack *extack)
{
#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_nh_id) {
if (fi->nh && cfg->fc_nh_id == fi->nh->id)
return 0;
return 1;
}
if (fi->nh) {
if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
return 1;
return 0;
}
if (cfg->fc_oif || cfg->fc_gw_family) {
struct fib_nh *nh;
nh = fib_info_nh(fi, 0);
if (cfg->fc_encap) {
if (fib_encap_match(net, cfg->fc_encap_type,
cfg->fc_encap, nh, cfg, extack))
return 1;
}
#ifdef CONFIG_IP_ROUTE_CLASSID
if (cfg->fc_flow &&
cfg->fc_flow != nh->nh_tclassid)
return 1;
#endif
if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
(cfg->fc_gw_family &&
cfg->fc_gw_family != nh->fib_nh_gw_family))
return 1;
if (cfg->fc_gw_family == AF_INET &&
cfg->fc_gw4 != nh->fib_nh_gw4)
return 1;
if (cfg->fc_gw_family == AF_INET6 &&
ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
return 1;
return 0;
}
#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->fib_nh_oif)
return 1;
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
int err;
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
nlav = nla_find(attrs, attrlen, RTA_VIA);
if (nla && nlav) {
NL_SET_ERR_MSG(extack,
"Nexthop configuration can not contain both GATEWAY and VIA");
return -EINVAL;
}
if (nla) {
__be32 gw;
err = fib_gw_from_attr(&gw, nla, extack);
if (err)
return err;
if (nh->fib_nh_gw_family != AF_INET ||
gw != nh->fib_nh_gw4)
return 1;
} else if (nlav) {
struct fib_config cfg2;
err = fib_gw_from_via(&cfg2, nlav, extack);
if (err)
return err;
switch (nh->fib_nh_gw_family) {
case AF_INET:
if (cfg2.fc_gw_family != AF_INET ||
cfg2.fc_gw4 != nh->fib_nh_gw4)
return 1;
break;
case AF_INET6:
if (cfg2.fc_gw_family != AF_INET6 ||
ipv6_addr_cmp(&cfg2.fc_gw6,
&nh->fib_nh_gw6))
return 1;
break;
}
}
#ifdef CONFIG_IP_ROUTE_CLASSID
nla = nla_find(attrs, attrlen, RTA_FLOW);
if (nla) {
if (nla_len(nla) < sizeof(u32)) {
NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
return -EINVAL;
}
if (nla_get_u32(nla) != nh->nh_tclassid)
return 1;