ipv4: Plumb support for nexthop object in a fib_info

Add 'struct nexthop' and nh_list list_head to fib_info. nh_list is the
fib_info side of the nexthop <-> fib_info relationship.

Add fi_list list_head to 'struct nexthop' to track fib_info entries
using a nexthop instance. Add __remove_nexthop_fib and add it to
__remove_nexthop to walk the new list_head and mark those fib entries
as dead when the nexthop is deleted.

Add a few nexthop helpers for use when a nexthop is added to fib_info:
- nexthop_cmp to determine if 2 nexthops are the same
- nexthop_path_fib_result to select a path for a multipath
  'struct nexthop'
- nexthop_fib_nhc to select a specific fib_nh_common within a
  multipath 'struct nexthop'

Update existing fib_info_nhc to use nexthop_fib_nhc if a fib_info uses
a 'struct nexthop', and mark fib_info_nh as only used for the non-nexthop
case.

Update the fib_info functions to check for fi->nh and take a different
path as needed:
- free_fib_info_rcu - put the nexthop object reference
- fib_release_info - remove the fib_info from the nexthop's fi_list
- nh_comp - use nexthop_cmp when either fib_info references a nexthop
  object
- fib_info_hashfn - use the nexthop id for the hashing vs the oif of
  each fib_nh in a fib_info
- fib_nlmsg_size - add space for the RTA_NH_ID attribute
- fib_create_info - verify nexthop reference can be taken, verify
  nexthop spec is valid for fib entry, and add fib_info to fi_list for
  a nexthop
- fib_select_multipath - use the new nexthop_path_fib_result to select a
  path when nexthop objects are used
- fib_table_lookup - if the 'struct nexthop' is a blackhole nexthop, treat
  it the same as a fib entry using 'blackhole'

The bulk of the changes are in fib_semantics.c and most of that is
moving the existing change_nexthops into an else branch.

Update the nexthop code to walk fi_list on a nexthop deleted to remove
fib entries referencing it.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2019-06-03 20:19:51 -07:00 committed by David S. Miller
parent dcb1ecb50e
commit 4c7e8084fd
5 changed files with 229 additions and 36 deletions

View File

@ -129,9 +129,12 @@ struct fib_nh {
* This structure contains data shared by many of routes.
*/
struct nexthop;
struct fib_info {
struct hlist_node fib_hash;
struct hlist_node fib_lhash;
struct list_head nh_list;
struct net *fib_net;
int fib_treeref;
refcount_t fib_clntref;
@ -151,6 +154,7 @@ struct fib_info {
int fib_nhs;
bool fib_nh_is_v6;
bool nh_updated;
struct nexthop *nh;
struct rcu_head rcu;
struct fib_nh fib_nh[0];
};

View File

@ -77,6 +77,7 @@ struct nh_group {
struct nexthop {
struct rb_node rb_node; /* entry on netns rbtree */
struct list_head fi_list; /* v4 entries using nh */
struct list_head grp_list; /* nh group entries using this nh */
struct net *net;
@ -110,6 +111,12 @@ static inline void nexthop_put(struct nexthop *nh)
call_rcu(&nh->rcu, nexthop_free_rcu);
}
static inline bool nexthop_cmp(const struct nexthop *nh1,
const struct nexthop *nh2)
{
return nh1 == nh2;
}
static inline bool nexthop_is_multipath(const struct nexthop *nh)
{
if (nh->is_group) {
@ -193,18 +200,59 @@ static inline bool nexthop_is_blackhole(const struct nexthop *nh)
return nhi->reject_nh;
}
static inline void nexthop_path_fib_result(struct fib_result *res, int hash)
{
struct nh_info *nhi;
struct nexthop *nh;
nh = nexthop_select_path(res->fi->nh, hash);
nhi = rcu_dereference(nh->nh_info);
res->nhc = &nhi->fib_nhc;
}
/* called with rcu read lock or rtnl held */
static inline
struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, int nhsel)
{
struct nh_info *nhi;
BUILD_BUG_ON(offsetof(struct fib_nh, nh_common) != 0);
BUILD_BUG_ON(offsetof(struct fib6_nh, nh_common) != 0);
if (nexthop_is_multipath(nh)) {
nh = nexthop_mpath_select(nh, nhsel);
if (!nh)
return NULL;
}
nhi = rcu_dereference_rtnl(nh->nh_info);
return &nhi->fib_nhc;
}
static inline unsigned int fib_info_num_path(const struct fib_info *fi)
{
if (unlikely(fi->nh))
return nexthop_num_path(fi->nh);
return fi->fib_nhs;
}
int fib_check_nexthop(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack);
static inline struct fib_nh_common *fib_info_nhc(struct fib_info *fi, int nhsel)
{
if (unlikely(fi->nh))
return nexthop_fib_nhc(fi->nh, nhsel);
return &fi->fib_nh[nhsel].nh_common;
}
/* only used when fib_nh is built into fib_info */
static inline struct fib_nh *fib_info_nh(struct fib_info *fi, int nhsel)
{
WARN_ON(fi->nh);
return &fi->fib_nh[nhsel];
}
#endif

View File

@ -236,9 +236,13 @@ static void free_fib_info_rcu(struct rcu_head *head)
{
struct fib_info *fi = container_of(head, struct fib_info, rcu);
change_nexthops(fi) {
fib_nh_release(fi->fib_net, nexthop_nh);
} endfor_nexthops(fi);
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);
@ -264,11 +268,15 @@ void fib_release_info(struct fib_info *fi)
hlist_del(&fi->fib_hash);
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
change_nexthops(fi) {
if (!nexthop_nh->fib_nh_dev)
continue;
hlist_del(&nexthop_nh->nh_hash);
} endfor_nexthops(fi)
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);
}
@ -279,6 +287,12 @@ 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);
@ -323,9 +337,14 @@ static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
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->fib_nh_oif);
} endfor_nexthops(fi)
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 (val ^ (val >> 7) ^ (val >> 12)) & mask;
}
@ -352,7 +371,7 @@ static struct fib_info *fib_find_info(struct fib_info *nfi)
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))
nh_comp(fi, nfi) == 0)
return fi;
}
@ -399,6 +418,9 @@ static inline size_t fib_nlmsg_size(struct fib_info *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 */
@ -585,6 +607,7 @@ static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
return nhs;
}
/* 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)
@ -683,6 +706,7 @@ errout:
return ret;
}
/* only called when fib_nh is integrated into fib_info */
static void fib_rebalance(struct fib_info *fi)
{
int total;
@ -1262,6 +1286,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
{
int err;
struct fib_info *fi = NULL;
struct nexthop *nh = NULL;
struct fib_info *ofi;
int nhs = 1;
struct net *net = cfg->fc_nlinfo.nl_net;
@ -1333,14 +1358,25 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
fi->fib_tb_id = cfg->fc_table;
fi->fib_nhs = nhs;
change_nexthops(fi) {
nexthop_nh->nh_parent = fi;
} endfor_nexthops(fi)
if (nh) {
if (!nexthop_get(nh)) {
NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
err = -EINVAL;
} else {
err = 0;
fi->nh = nh;
}
} else {
change_nexthops(fi) {
nexthop_nh->nh_parent = fi;
} endfor_nexthops(fi)
if (cfg->fc_mp)
err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
else
err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
if (cfg->fc_mp)
err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
extack);
else
err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
}
if (err != 0)
goto failure;
@ -1371,7 +1407,11 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
goto err_inval;
}
if (cfg->fc_scope == RT_SCOPE_HOST) {
if (fi->nh) {
err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
if (err)
goto failure;
} else if (cfg->fc_scope == RT_SCOPE_HOST) {
struct fib_nh *nh = fi->fib_nh;
/* Local address is added. */
@ -1411,14 +1451,16 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
goto err_inval;
}
change_nexthops(fi) {
fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
fi->fib_scope);
if (nexthop_nh->fib_nh_gw_family == AF_INET6)
fi->fib_nh_is_v6 = true;
} endfor_nexthops(fi)
if (!fi->nh) {
change_nexthops(fi) {
fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
fi->fib_scope);
if (nexthop_nh->fib_nh_gw_family == AF_INET6)
fi->fib_nh_is_v6 = true;
} endfor_nexthops(fi)
fib_rebalance(fi);
fib_rebalance(fi);
}
link_it:
ofi = fib_find_info(fi);
@ -1440,16 +1482,20 @@ link_it:
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 (fi->nh) {
list_add(&fi->nh_list, &nh->fi_list);
} else {
change_nexthops(fi) {
struct hlist_head *head;
unsigned int hash;
if (!nexthop_nh->fib_nh_dev)
continue;
hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
head = &fib_info_devhash[hash];
hlist_add_head(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
if (!nexthop_nh->fib_nh_dev)
continue;
hash = fib_devindex_hashfn(nexthop_nh->fib_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;
@ -1576,6 +1622,12 @@ static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
if (!mp)
goto nla_put_failure;
if (unlikely(fi->nh)) {
if (nexthop_mpath_fill_node(skb, fi->nh) < 0)
goto nla_put_failure;
goto mp_end;
}
for_nexthops(fi) {
if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight) < 0)
goto nla_put_failure;
@ -1586,6 +1638,7 @@ static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
#endif
} endfor_nexthops(fi);
mp_end:
nla_nest_end(skb, mp);
return 0;
@ -1640,6 +1693,14 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
if (fi->fib_prefsrc &&
nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
goto nla_put_failure;
if (fi->nh) {
if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
goto nla_put_failure;
if (nexthop_is_blackhole(fi->nh))
rtm->rtm_type = RTN_BLACKHOLE;
}
if (nhs == 1) {
const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
unsigned char flags = 0;
@ -1784,6 +1845,8 @@ void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
* 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
*
* only used when fib_nh is built into fib_info
*/
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
{
@ -1931,6 +1994,8 @@ out:
/*
* Dead device goes up. We wake up dead nexthops.
* It takes sense only on multipath routes.
*
* only used when fib_nh is built into fib_info
*/
int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
{
@ -2025,6 +2090,11 @@ void fib_select_multipath(struct fib_result *res, int hash)
struct net *net = fi->fib_net;
bool first = false;
if (unlikely(res->fi->nh)) {
nexthop_path_fib_result(res, hash);
return;
}
change_nexthops(fi) {
if (net->ipv4.sysctl_fib_multipath_use_neigh) {
if (!fib_good_nh(nexthop_nh))

View File

@ -1461,6 +1461,7 @@ found:
fib_alias_accessed(fa);
err = fib_props[fa->fa_type].error;
if (unlikely(err < 0)) {
out_reject:
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_passed);
#endif
@ -1469,6 +1470,12 @@ found:
}
if (fi->fib_flags & RTNH_F_DEAD)
continue;
if (unlikely(fi->nh && nexthop_is_blackhole(fi->nh))) {
err = fib_props[RTN_BLACKHOLE].error;
goto out_reject;
}
for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);

View File

@ -105,6 +105,7 @@ static struct nexthop *nexthop_alloc(void)
nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
if (nh) {
INIT_LIST_HEAD(&nh->fi_list);
INIT_LIST_HEAD(&nh->grp_list);
}
return nh;
@ -515,6 +516,54 @@ struct nexthop *nexthop_select_path(struct nexthop *nh, int hash)
}
EXPORT_SYMBOL_GPL(nexthop_select_path);
static int nexthop_check_scope(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
nhi = rtnl_dereference(nh->nh_info);
if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {
NL_SET_ERR_MSG(extack,
"Route with host scope can not have a gateway");
return -EINVAL;
}
if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {
NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");
return -EINVAL;
}
return 0;
}
/* Invoked by fib add code to verify nexthop by id is ok with
* config for prefix; parts of fib_check_nh not done when nexthop
* object is used.
*/
int fib_check_nexthop(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
int err = 0;
if (nh->is_group) {
struct nh_group *nhg;
if (scope == RT_SCOPE_HOST) {
NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");
err = -EINVAL;
goto out;
}
nhg = rtnl_dereference(nh->nh_grp);
/* all nexthops in a group have the same scope */
err = nexthop_check_scope(nhg->nh_entries[0].nh, scope, extack);
} else {
err = nexthop_check_scope(nh, scope, extack);
}
out:
return err;
}
static void nh_group_rebalance(struct nh_group *nhg)
{
int total = 0;
@ -607,9 +656,24 @@ static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo)
}
}
static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
{
bool do_flush = false;
struct fib_info *fi;
list_for_each_entry(fi, &nh->fi_list, nh_list) {
fi->fib_flags |= RTNH_F_DEAD;
do_flush = true;
}
if (do_flush)
fib_flush(net);
}
static void __remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
__remove_nexthop_fib(net, nh);
if (nh->is_group) {
remove_nexthop_group(nh, nlinfo);
} else {