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net/ipv6: Add fib6_null_entry
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ip6_null_entry will stay a dst based return for lookups that fail to
match an entry.

Add a new fib6_null_entry which constitutes the root node and leafs
for fibs. Replace existing references to ip6_null_entry with the
new fib6_null_entry when dealing with FIBs.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@dsahern @davem330
dsahern authored and davem330 committed Apr 18, 2018
1 parent 1489568 commit 421842e
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Showing 3 changed files with 58 additions and 33 deletions.
3 changes: 2 additions & 1 deletion include/net/netns/ipv6.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,8 @@ struct netns_ipv6 {
#endif
struct xt_table *ip6table_nat;
#endif
struct rt6_info *ip6_null_entry;
struct rt6_info *fib6_null_entry;
struct rt6_info *ip6_null_entry;
struct rt6_statistics *rt6_stats;
struct timer_list ip6_fib_timer;
struct hlist_head *fib_table_hash;
Expand Down
26 changes: 13 additions & 13 deletions net/ipv6/ip6_fib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -231,7 +231,7 @@ static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
if (table) {
table->tb6_id = id;
rcu_assign_pointer(table->tb6_root.leaf,
net->ipv6.ip6_null_entry);
net->ipv6.fib6_null_entry);
table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
inet_peer_base_init(&table->tb6_peers);
}
Expand Down Expand Up @@ -369,7 +369,7 @@ struct fib6_dump_arg {

static void fib6_rt_dump(struct rt6_info *rt, struct fib6_dump_arg *arg)
{
if (rt == arg->net->ipv6.ip6_null_entry)
if (rt == arg->net->ipv6.fib6_null_entry)
return;
call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
}
Expand Down Expand Up @@ -658,7 +658,7 @@ static struct fib6_node *fib6_add_1(struct net *net,
/* remove null_entry in the root node */
} else if (fn->fn_flags & RTN_TL_ROOT &&
rcu_access_pointer(fn->leaf) ==
net->ipv6.ip6_null_entry) {
net->ipv6.fib6_null_entry) {
RCU_INIT_POINTER(fn->leaf, NULL);
}

Expand Down Expand Up @@ -1171,9 +1171,9 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt,
if (!sfn)
goto failure;

atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
atomic_inc(&info->nl_net->ipv6.fib6_null_entry->rt6i_ref);
rcu_assign_pointer(sfn->leaf,
info->nl_net->ipv6.ip6_null_entry);
info->nl_net->ipv6.fib6_null_entry);
sfn->fn_flags = RTN_ROOT;

/* Now add the first leaf node to new subtree */
Expand Down Expand Up @@ -1212,7 +1212,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt,
if (fn->fn_flags & RTN_TL_ROOT) {
/* put back null_entry for root node */
rcu_assign_pointer(fn->leaf,
info->nl_net->ipv6.ip6_null_entry);
info->nl_net->ipv6.fib6_null_entry);
} else {
atomic_inc(&rt->rt6i_ref);
rcu_assign_pointer(fn->leaf, rt);
Expand Down Expand Up @@ -1251,7 +1251,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt,
if (!pn_leaf) {
WARN_ON(!pn_leaf);
pn_leaf =
info->nl_net->ipv6.ip6_null_entry;
info->nl_net->ipv6.fib6_null_entry;
}
#endif
atomic_inc(&pn_leaf->rt6i_ref);
Expand Down Expand Up @@ -1494,7 +1494,7 @@ static struct rt6_info *fib6_find_prefix(struct net *net,
struct fib6_node *child_left, *child_right;

if (fn->fn_flags & RTN_ROOT)
return net->ipv6.ip6_null_entry;
return net->ipv6.fib6_null_entry;

while (fn) {
child_left = rcu_dereference_protected(fn->left,
Expand Down Expand Up @@ -1531,7 +1531,7 @@ static struct fib6_node *fib6_repair_tree(struct net *net,

/* Set fn->leaf to null_entry for root node. */
if (fn->fn_flags & RTN_TL_ROOT) {
rcu_assign_pointer(fn->leaf, net->ipv6.ip6_null_entry);
rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
return fn;
}

Expand Down Expand Up @@ -1576,7 +1576,7 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
#if RT6_DEBUG >= 2
if (!new_fn_leaf) {
WARN_ON(!new_fn_leaf);
new_fn_leaf = net->ipv6.ip6_null_entry;
new_fn_leaf = net->ipv6.fib6_null_entry;
}
#endif
atomic_inc(&new_fn_leaf->rt6i_ref);
Expand Down Expand Up @@ -1726,7 +1726,7 @@ int fib6_del(struct rt6_info *rt, struct nl_info *info)
return -ENOENT;
}
#endif
if (!fn || rt == net->ipv6.ip6_null_entry)
if (!fn || rt == net->ipv6.fib6_null_entry)
return -ENOENT;

WARN_ON(!(fn->fn_flags & RTN_RTINFO));
Expand Down Expand Up @@ -2087,7 +2087,7 @@ static int __net_init fib6_net_init(struct net *net)

net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
net->ipv6.ip6_null_entry);
net->ipv6.fib6_null_entry);
net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
Expand All @@ -2099,7 +2099,7 @@ static int __net_init fib6_net_init(struct net *net)
goto out_fib6_main_tbl;
net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
net->ipv6.ip6_null_entry);
net->ipv6.fib6_null_entry);
net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
Expand Down
62 changes: 43 additions & 19 deletions net/ipv6/route.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -276,6 +276,15 @@ static const u32 ip6_template_metrics[RTAX_MAX] = {
[RTAX_HOPLIMIT - 1] = 0,
};

static const struct rt6_info fib6_null_entry_template = {
.rt6i_flags = (RTF_REJECT | RTF_NONEXTHOP),
.rt6i_protocol = RTPROT_KERNEL,
.rt6i_metric = ~(u32)0,
.rt6i_ref = ATOMIC_INIT(1),
.fib6_type = RTN_UNREACHABLE,
.fib6_metrics = (struct dst_metrics *)&dst_default_metrics,
};

static const struct rt6_info ip6_null_entry_template = {
.dst = {
.__refcnt = ATOMIC_INIT(1),
Expand Down Expand Up @@ -522,10 +531,10 @@ static inline struct rt6_info *rt6_device_match(struct net *net,
return local;

if (flags & RT6_LOOKUP_F_IFACE)
return net->ipv6.ip6_null_entry;
return net->ipv6.fib6_null_entry;
}

return rt->fib6_nh.nh_flags & RTNH_F_DEAD ? net->ipv6.ip6_null_entry : rt;
return rt->fib6_nh.nh_flags & RTNH_F_DEAD ? net->ipv6.fib6_null_entry : rt;
}

#ifdef CONFIG_IPV6_ROUTER_PREF
Expand Down Expand Up @@ -758,8 +767,8 @@ static struct rt6_info *rt6_select(struct net *net, struct fib6_node *fn,
bool do_rr = false;
int key_plen;

if (!leaf || leaf == net->ipv6.ip6_null_entry)
return net->ipv6.ip6_null_entry;
if (!leaf || leaf == net->ipv6.fib6_null_entry)
return net->ipv6.fib6_null_entry;

rt0 = rcu_dereference(fn->rr_ptr);
if (!rt0)
Expand All @@ -776,7 +785,7 @@ static struct rt6_info *rt6_select(struct net *net, struct fib6_node *fn,
key_plen = rt0->rt6i_src.plen;
#endif
if (fn->fn_bit != key_plen)
return net->ipv6.ip6_null_entry;
return net->ipv6.fib6_null_entry;

match = find_rr_leaf(fn, leaf, rt0, rt0->rt6i_metric, oif, strict,
&do_rr);
Expand All @@ -797,7 +806,7 @@ static struct rt6_info *rt6_select(struct net *net, struct fib6_node *fn,
}
}

return match ? match : net->ipv6.ip6_null_entry;
return match ? match : net->ipv6.fib6_null_entry;
}

static bool rt6_is_gw_or_nonexthop(const struct rt6_info *rt)
Expand Down Expand Up @@ -1063,15 +1072,15 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net,
restart:
rt = rcu_dereference(fn->leaf);
if (!rt) {
rt = net->ipv6.ip6_null_entry;
rt = net->ipv6.fib6_null_entry;
} else {
rt = rt6_device_match(net, rt, &fl6->saddr,
fl6->flowi6_oif, flags);
if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
rt = rt6_multipath_select(net, rt, fl6, fl6->flowi6_oif,
skb, flags);
}
if (rt == net->ipv6.ip6_null_entry) {
if (rt == net->ipv6.fib6_null_entry) {
fn = fib6_backtrack(fn, &fl6->saddr);
if (fn)
goto restart;
Expand Down Expand Up @@ -1820,7 +1829,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
rt = rt6_select(net, fn, oif, strict);
if (rt->rt6i_nsiblings)
rt = rt6_multipath_select(net, rt, fl6, oif, skb, strict);
if (rt == net->ipv6.ip6_null_entry) {
if (rt == net->ipv6.fib6_null_entry) {
fn = fib6_backtrack(fn, &fl6->saddr);
if (fn)
goto redo_rt6_select;
Expand All @@ -1837,7 +1846,8 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
if (rt_cache)
rt = rt_cache;

if (rt == net->ipv6.ip6_null_entry) {
if (rt == net->ipv6.fib6_null_entry) {
rt = net->ipv6.ip6_null_entry;
rcu_read_unlock();
dst_hold(&rt->dst);
trace_fib6_table_lookup(net, rt, table, fl6);
Expand Down Expand Up @@ -2412,13 +2422,13 @@ static struct rt6_info *__ip6_route_redirect(struct net *net,
}

if (!rt)
rt = net->ipv6.ip6_null_entry;
rt = net->ipv6.fib6_null_entry;
else if (rt->rt6i_flags & RTF_REJECT) {
rt = net->ipv6.ip6_null_entry;
goto out;
}

if (rt == net->ipv6.ip6_null_entry) {
if (rt == net->ipv6.fib6_null_entry) {
fn = fib6_backtrack(fn, &fl6->saddr);
if (fn)
goto restart;
Expand Down Expand Up @@ -3051,7 +3061,7 @@ static int __ip6_del_rt(struct rt6_info *rt, struct nl_info *info)
struct fib6_table *table;
int err;

if (rt == net->ipv6.ip6_null_entry) {
if (rt == net->ipv6.fib6_null_entry) {
err = -ENOENT;
goto out;
}
Expand Down Expand Up @@ -3081,7 +3091,7 @@ static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg)
struct fib6_table *table;
int err = -ENOENT;

if (rt == net->ipv6.ip6_null_entry)
if (rt == net->ipv6.fib6_null_entry)
goto out_put;
table = rt->rt6i_table;
spin_lock_bh(&table->tb6_lock);
Expand Down Expand Up @@ -3634,7 +3644,7 @@ static int fib6_remove_prefsrc(struct rt6_info *rt, void *arg)
struct in6_addr *addr = ((struct arg_dev_net_ip *)arg)->addr;

if (((void *)rt->fib6_nh.nh_dev == dev || !dev) &&
rt != net->ipv6.ip6_null_entry &&
rt != net->ipv6.fib6_null_entry &&
ipv6_addr_equal(addr, &rt->rt6i_prefsrc.addr)) {
spin_lock_bh(&rt6_exception_lock);
/* remove prefsrc entry */
Expand Down Expand Up @@ -3789,7 +3799,7 @@ static int fib6_ifup(struct rt6_info *rt, void *p_arg)
const struct arg_netdev_event *arg = p_arg;
struct net *net = dev_net(arg->dev);

if (rt != net->ipv6.ip6_null_entry && rt->fib6_nh.nh_dev == arg->dev) {
if (rt != net->ipv6.fib6_null_entry && rt->fib6_nh.nh_dev == arg->dev) {
rt->fib6_nh.nh_flags &= ~arg->nh_flags;
fib6_update_sernum_upto_root(net, rt);
rt6_multipath_rebalance(rt);
Expand Down Expand Up @@ -3873,7 +3883,7 @@ static int fib6_ifdown(struct rt6_info *rt, void *p_arg)
const struct net_device *dev = arg->dev;
struct net *net = dev_net(dev);

if (rt == net->ipv6.ip6_null_entry)
if (rt == net->ipv6.fib6_null_entry)
return 0;

switch (arg->event) {
Expand Down Expand Up @@ -4624,7 +4634,7 @@ int rt6_dump_route(struct rt6_info *rt, void *p_arg)
struct rt6_rtnl_dump_arg *arg = (struct rt6_rtnl_dump_arg *) p_arg;
struct net *net = arg->net;

if (rt == net->ipv6.ip6_null_entry)
if (rt == net->ipv6.fib6_null_entry)
return 0;

if (nlmsg_len(arg->cb->nlh) >= sizeof(struct rtmsg)) {
Expand Down Expand Up @@ -4813,6 +4823,8 @@ static int ip6_route_dev_notify(struct notifier_block *this,
return NOTIFY_OK;

if (event == NETDEV_REGISTER) {
net->ipv6.fib6_null_entry->fib6_nh.nh_dev = dev;
net->ipv6.fib6_null_entry->rt6i_idev = in6_dev_get(dev);
net->ipv6.ip6_null_entry->dst.dev = dev;
net->ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(dev);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
Expand All @@ -4826,6 +4838,7 @@ static int ip6_route_dev_notify(struct notifier_block *this,
/* NETDEV_UNREGISTER could be fired for multiple times by
* netdev_wait_allrefs(). Make sure we only call this once.
*/
in6_dev_put_clear(&net->ipv6.fib6_null_entry->rt6i_idev);
in6_dev_put_clear(&net->ipv6.ip6_null_entry->rt6i_idev);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
in6_dev_put_clear(&net->ipv6.ip6_prohibit_entry->rt6i_idev);
Expand Down Expand Up @@ -5009,11 +5022,17 @@ static int __net_init ip6_route_net_init(struct net *net)
if (dst_entries_init(&net->ipv6.ip6_dst_ops) < 0)
goto out_ip6_dst_ops;

net->ipv6.fib6_null_entry = kmemdup(&fib6_null_entry_template,
sizeof(*net->ipv6.fib6_null_entry),
GFP_KERNEL);
if (!net->ipv6.fib6_null_entry)
goto out_ip6_dst_entries;

net->ipv6.ip6_null_entry = kmemdup(&ip6_null_entry_template,
sizeof(*net->ipv6.ip6_null_entry),
GFP_KERNEL);
if (!net->ipv6.ip6_null_entry)
goto out_ip6_dst_entries;
goto out_fib6_null_entry;
net->ipv6.ip6_null_entry->dst.ops = &net->ipv6.ip6_dst_ops;
dst_init_metrics(&net->ipv6.ip6_null_entry->dst,
ip6_template_metrics, true);
Expand Down Expand Up @@ -5060,6 +5079,8 @@ static int __net_init ip6_route_net_init(struct net *net)
out_ip6_null_entry:
kfree(net->ipv6.ip6_null_entry);
#endif
out_fib6_null_entry:
kfree(net->ipv6.fib6_null_entry);
out_ip6_dst_entries:
dst_entries_destroy(&net->ipv6.ip6_dst_ops);
out_ip6_dst_ops:
Expand All @@ -5068,6 +5089,7 @@ static int __net_init ip6_route_net_init(struct net *net)

static void __net_exit ip6_route_net_exit(struct net *net)
{
kfree(net->ipv6.fib6_null_entry);
kfree(net->ipv6.ip6_null_entry);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
kfree(net->ipv6.ip6_prohibit_entry);
Expand Down Expand Up @@ -5138,6 +5160,8 @@ void __init ip6_route_init_special_entries(void)
/* Registering of the loopback is done before this portion of code,
* the loopback reference in rt6_info will not be taken, do it
* manually for init_net */
init_net.ipv6.fib6_null_entry->fib6_nh.nh_dev = init_net.loopback_dev;
init_net.ipv6.fib6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
init_net.ipv6.ip6_null_entry->dst.dev = init_net.loopback_dev;
init_net.ipv6.ip6_null_entry->rt6i_idev = in6_dev_get(init_net.loopback_dev);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
Expand Down

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