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linux-sg2042/net/ipv6/ip6_fib.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux INET6 implementation
* Forwarding Information Database
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* Changes:
* Yuji SEKIYA @USAGI: Support default route on router node;
* remove ip6_null_entry from the top of
* routing table.
* Ville Nuorvala: Fixed routing subtrees.
*/
#define pr_fmt(fmt) "IPv6: " fmt
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/net.h>
#include <linux/route.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/lwtunnel.h>
#include <net/fib_notifier.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
static struct kmem_cache *fib6_node_kmem __read_mostly;
struct fib6_cleaner {
struct fib6_walker w;
struct net *net;
int (*func)(struct fib6_info *, void *arg);
int sernum;
void *arg;
bool skip_notify;
};
#ifdef CONFIG_IPV6_SUBTREES
#define FWS_INIT FWS_S
#else
#define FWS_INIT FWS_L
#endif
static struct fib6_info *fib6_find_prefix(struct net *net,
struct fib6_table *table,
struct fib6_node *fn);
static struct fib6_node *fib6_repair_tree(struct net *net,
struct fib6_table *table,
struct fib6_node *fn);
static int fib6_walk(struct net *net, struct fib6_walker *w);
static int fib6_walk_continue(struct fib6_walker *w);
/*
* A routing update causes an increase of the serial number on the
* affected subtree. This allows for cached routes to be asynchronously
* tested when modifications are made to the destination cache as a
* result of redirects, path MTU changes, etc.
*/
static void fib6_gc_timer_cb(struct timer_list *t);
#define FOR_WALKERS(net, w) \
list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
static void fib6_walker_link(struct net *net, struct fib6_walker *w)
{
write_lock_bh(&net->ipv6.fib6_walker_lock);
list_add(&w->lh, &net->ipv6.fib6_walkers);
write_unlock_bh(&net->ipv6.fib6_walker_lock);
}
static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
{
write_lock_bh(&net->ipv6.fib6_walker_lock);
list_del(&w->lh);
write_unlock_bh(&net->ipv6.fib6_walker_lock);
}
static int fib6_new_sernum(struct net *net)
{
int new, old;
do {
old = atomic_read(&net->ipv6.fib6_sernum);
new = old < INT_MAX ? old + 1 : 1;
} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
old, new) != old);
return new;
}
enum {
FIB6_NO_SERNUM_CHANGE = 0,
};
void fib6_update_sernum(struct net *net, struct fib6_info *f6i)
{
struct fib6_node *fn;
fn = rcu_dereference_protected(f6i->fib6_node,
lockdep_is_held(&f6i->fib6_table->tb6_lock));
if (fn)
fn->fn_sernum = fib6_new_sernum(net);
}
/*
* Auxiliary address test functions for the radix tree.
*
* These assume a 32bit processor (although it will work on
* 64bit processors)
*/
/*
* test bit
*/
#if defined(__LITTLE_ENDIAN)
# define BITOP_BE32_SWIZZLE (0x1F & ~7)
#else
# define BITOP_BE32_SWIZZLE 0
#endif
static __be32 addr_bit_set(const void *token, int fn_bit)
{
const __be32 *addr = token;
/*
* Here,
* 1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
* is optimized version of
* htonl(1 << ((~fn_bit)&0x1F))
* See include/asm-generic/bitops/le.h.
*/
return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
addr[fn_bit >> 5];
}
struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh)
{
struct fib6_info *f6i;
size_t sz = sizeof(*f6i);
if (with_fib6_nh)
sz += sizeof(struct fib6_nh);
f6i = kzalloc(sz, gfp_flags);
if (!f6i)
return NULL;
/* fib6_siblings is a union with nh_list, so this initializes both */
INIT_LIST_HEAD(&f6i->fib6_siblings);
refcount_set(&f6i->fib6_ref, 1);
return f6i;
}
void fib6_info_destroy_rcu(struct rcu_head *head)
{
struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
WARN_ON(f6i->fib6_node);
if (f6i->nh)
nexthop_put(f6i->nh);
else
fib6_nh_release(f6i->fib6_nh);
ip_fib_metrics_put(f6i->fib6_metrics);
kfree(f6i);
}
EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
static struct fib6_node *node_alloc(struct net *net)
{
struct fib6_node *fn;
fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
if (fn)
net->ipv6.rt6_stats->fib_nodes++;
return fn;
}
static void node_free_immediate(struct net *net, struct fib6_node *fn)
{
kmem_cache_free(fib6_node_kmem, fn);
net->ipv6.rt6_stats->fib_nodes--;
}
static void node_free_rcu(struct rcu_head *head)
{
struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
kmem_cache_free(fib6_node_kmem, fn);
}
static void node_free(struct net *net, struct fib6_node *fn)
{
call_rcu(&fn->rcu, node_free_rcu);
net->ipv6.rt6_stats->fib_nodes--;
}
static void fib6_free_table(struct fib6_table *table)
{
inetpeer_invalidate_tree(&table->tb6_peers);
kfree(table);
}
static void fib6_link_table(struct net *net, struct fib6_table *tb)
{
unsigned int h;
/*
* Initialize table lock at a single place to give lockdep a key,
* tables aren't visible prior to being linked to the list.
*/
spin_lock_init(&tb->tb6_lock);
h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
/*
* No protection necessary, this is the only list mutatation
* operation, tables never disappear once they exist.
*/
hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
}
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
{
struct fib6_table *table;
table = kzalloc(sizeof(*table), GFP_ATOMIC);
if (table) {
table->tb6_id = id;
rcu_assign_pointer(table->tb6_root.leaf,
net->ipv6.fib6_null_entry);
table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
inet_peer_base_init(&table->tb6_peers);
}
return table;
}
struct fib6_table *fib6_new_table(struct net *net, u32 id)
{
struct fib6_table *tb;
if (id == 0)
id = RT6_TABLE_MAIN;
tb = fib6_get_table(net, id);
if (tb)
return tb;
tb = fib6_alloc_table(net, id);
if (tb)
fib6_link_table(net, tb);
return tb;
}
EXPORT_SYMBOL_GPL(fib6_new_table);
struct fib6_table *fib6_get_table(struct net *net, u32 id)
{
struct fib6_table *tb;
struct hlist_head *head;
unsigned int h;
if (id == 0)
id = RT6_TABLE_MAIN;
h = id & (FIB6_TABLE_HASHSZ - 1);
rcu_read_lock();
head = &net->ipv6.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
if (tb->tb6_id == id) {
rcu_read_unlock();
return tb;
}
}
rcu_read_unlock();
return NULL;
}
EXPORT_SYMBOL_GPL(fib6_get_table);
static void __net_init fib6_tables_init(struct net *net)
{
fib6_link_table(net, net->ipv6.fib6_main_tbl);
fib6_link_table(net, net->ipv6.fib6_local_tbl);
}
#else
struct fib6_table *fib6_new_table(struct net *net, u32 id)
{
return fib6_get_table(net, id);
}
struct fib6_table *fib6_get_table(struct net *net, u32 id)
{
return net->ipv6.fib6_main_tbl;
}
struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
const struct sk_buff *skb,
int flags, pol_lookup_t lookup)
{
struct rt6_info *rt;
rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
if (rt->dst.error == -EAGAIN) {
ip6_rt_put_flags(rt, flags);
rt = net->ipv6.ip6_null_entry;
if (!(flags & RT6_LOOKUP_F_DST_NOREF))
dst_hold(&rt->dst);
}
return &rt->dst;
}
/* called with rcu lock held; no reference taken on fib6_info */
int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
struct fib6_result *res, int flags)
{
return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
res, flags);
}
static void __net_init fib6_tables_init(struct net *net)
{
fib6_link_table(net, net->ipv6.fib6_main_tbl);
}
#endif
unsigned int fib6_tables_seq_read(struct net *net)
{
unsigned int h, fib_seq = 0;
rcu_read_lock();
for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
struct hlist_head *head = &net->ipv6.fib_table_hash[h];
struct fib6_table *tb;
hlist_for_each_entry_rcu(tb, head, tb6_hlist)
fib_seq += tb->fib_seq;
}
rcu_read_unlock();
return fib_seq;
}
static int call_fib6_entry_notifier(struct notifier_block *nb,
enum fib_event_type event_type,
struct fib6_info *rt,
struct netlink_ext_ack *extack)
{
struct fib6_entry_notifier_info info = {
.info.extack = extack,
.rt = rt,
};
return call_fib6_notifier(nb, event_type, &info.info);
}
int call_fib6_entry_notifiers(struct net *net,
enum fib_event_type event_type,
struct fib6_info *rt,
struct netlink_ext_ack *extack)
{
struct fib6_entry_notifier_info info = {
.info.extack = extack,
.rt = rt,
};
rt->fib6_table->fib_seq++;
return call_fib6_notifiers(net, event_type, &info.info);
}
int call_fib6_multipath_entry_notifiers(struct net *net,
enum fib_event_type event_type,
struct fib6_info *rt,
unsigned int nsiblings,
struct netlink_ext_ack *extack)
{
struct fib6_entry_notifier_info info = {
.info.extack = extack,
.rt = rt,
.nsiblings = nsiblings,
};
rt->fib6_table->fib_seq++;
return call_fib6_notifiers(net, event_type, &info.info);
}
struct fib6_dump_arg {
struct net *net;
struct notifier_block *nb;
struct netlink_ext_ack *extack;
};
static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
{
if (rt == arg->net->ipv6.fib6_null_entry)
return 0;
return call_fib6_entry_notifier(arg->nb, FIB_EVENT_ENTRY_ADD,
rt, arg->extack);
}
static int fib6_node_dump(struct fib6_walker *w)
{
struct fib6_info *rt;
int err = 0;
for_each_fib6_walker_rt(w) {
err = fib6_rt_dump(rt, w->args);
if (err)
break;
}
w->leaf = NULL;
return err;
}
static int fib6_table_dump(struct net *net, struct fib6_table *tb,
struct fib6_walker *w)
{
int err;
w->root = &tb->tb6_root;
spin_lock_bh(&tb->tb6_lock);
err = fib6_walk(net, w);
spin_unlock_bh(&tb->tb6_lock);
return err;
}
/* Called with rcu_read_lock() */
int fib6_tables_dump(struct net *net, struct notifier_block *nb,
struct netlink_ext_ack *extack)
{
struct fib6_dump_arg arg;
struct fib6_walker *w;
unsigned int h;
int err = 0;
w = kzalloc(sizeof(*w), GFP_ATOMIC);
if (!w)
return -ENOMEM;
w->func = fib6_node_dump;
arg.net = net;
arg.nb = nb;
arg.extack = extack;
w->args = &arg;
for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
struct hlist_head *head = &net->ipv6.fib_table_hash[h];
struct fib6_table *tb;
hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
err = fib6_table_dump(net, tb, w);
if (err < 0)
goto out;
}
}
out:
kfree(w);
return err;
}
static int fib6_dump_node(struct fib6_walker *w)
{
int res;
struct fib6_info *rt;
for_each_fib6_walker_rt(w) {
res = rt6_dump_route(rt, w->args, w->skip_in_node);
if (res >= 0) {
/* Frame is full, suspend walking */
w->leaf = rt;
/* We'll restart from this node, so if some routes were
* already dumped, skip them next time.
*/
w->skip_in_node += res;
return 1;
}
w->skip_in_node = 0;
/* Multipath routes are dumped in one route with the
* RTA_MULTIPATH attribute. Jump 'rt' to point to the
* last sibling of this route (no need to dump the
* sibling routes again)
*/
if (rt->fib6_nsiblings)
rt = list_last_entry(&rt->fib6_siblings,
struct fib6_info,
fib6_siblings);
}
w->leaf = NULL;
return 0;
}
static void fib6_dump_end(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct fib6_walker *w = (void *)cb->args[2];
if (w) {
if (cb->args[4]) {
cb->args[4] = 0;
fib6_walker_unlink(net, w);
}
cb->args[2] = 0;
kfree(w);
}
cb->done = (void *)cb->args[3];
cb->args[1] = 3;
}
static int fib6_dump_done(struct netlink_callback *cb)
{
fib6_dump_end(cb);
return cb->done ? cb->done(cb) : 0;
}
static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
struct fib6_walker *w;
int res;
w = (void *)cb->args[2];
w->root = &table->tb6_root;
if (cb->args[4] == 0) {
w->count = 0;
w->skip = 0;
w->skip_in_node = 0;
spin_lock_bh(&table->tb6_lock);
res = fib6_walk(net, w);
spin_unlock_bh(&table->tb6_lock);
if (res > 0) {
cb->args[4] = 1;
cb->args[5] = w->root->fn_sernum;
}
} else {
if (cb->args[5] != w->root->fn_sernum) {
/* Begin at the root if the tree changed */
cb->args[5] = w->root->fn_sernum;
w->state = FWS_INIT;
w->node = w->root;
w->skip = w->count;
w->skip_in_node = 0;
} else
w->skip = 0;
spin_lock_bh(&table->tb6_lock);
res = fib6_walk_continue(w);
spin_unlock_bh(&table->tb6_lock);
if (res <= 0) {
fib6_walker_unlink(net, w);
cb->args[4] = 0;
}
}
return res;
}
static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
{
struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
.filter.dump_routes = true };
const struct nlmsghdr *nlh = cb->nlh;
struct net *net = sock_net(skb->sk);
unsigned int h, s_h;
unsigned int e = 0, s_e;
struct fib6_walker *w;
struct fib6_table *tb;
struct hlist_head *head;
int res = 0;
if (cb->strict_check) {
int err;
err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
if (err < 0)
return err;
} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
struct rtmsg *rtm = nlmsg_data(nlh);
if (rtm->rtm_flags & RTM_F_PREFIX)
arg.filter.flags = RTM_F_PREFIX;
}
w = (void *)cb->args[2];
if (!w) {
/* New dump:
*
* 1. hook callback destructor.
*/
cb->args[3] = (long)cb->done;
cb->done = fib6_dump_done;
/*
* 2. allocate and initialize walker.
*/
w = kzalloc(sizeof(*w), GFP_ATOMIC);
if (!w)
return -ENOMEM;
w->func = fib6_dump_node;
cb->args[2] = (long)w;
}
arg.skb = skb;
arg.cb = cb;
arg.net = net;
w->args = &arg;
if (arg.filter.table_id) {
tb = fib6_get_table(net, arg.filter.table_id);
if (!tb) {
if (arg.filter.dump_all_families)
goto out;
NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
return -ENOENT;
}
if (!cb->args[0]) {
res = fib6_dump_table(tb, skb, cb);
if (!res)
cb->args[0] = 1;
}
goto out;
}
s_h = cb->args[0];
s_e = cb->args[1];
rcu_read_lock();
for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
e = 0;
head = &net->ipv6.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
if (e < s_e)
goto next;
res = fib6_dump_table(tb, skb, cb);
if (res != 0)
goto out_unlock;
next:
e++;
}
}
out_unlock:
rcu_read_unlock();
cb->args[1] = e;
cb->args[0] = h;
out:
res = res < 0 ? res : skb->len;
if (res <= 0)
fib6_dump_end(cb);
return res;
}
void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
{
if (!f6i)
return;
if (f6i->fib6_metrics == &dst_default_metrics) {
struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
if (!p)
return;
refcount_set(&p->refcnt, 1);
f6i->fib6_metrics = p;
}
f6i->fib6_metrics->metrics[metric - 1] = val;
}
/*
* Routing Table
*
* return the appropriate node for a routing tree "add" operation
* by either creating and inserting or by returning an existing
* node.
*/
static struct fib6_node *fib6_add_1(struct net *net,
struct fib6_table *table,
struct fib6_node *root,
struct in6_addr *addr, int plen,
int offset, int allow_create,
int replace_required,
struct netlink_ext_ack *extack)
{
struct fib6_node *fn, *in, *ln;
struct fib6_node *pn = NULL;
struct rt6key *key;
int bit;
__be32 dir = 0;
RT6_TRACE("fib6_add_1\n");
/* insert node in tree */
fn = root;
do {
struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
lockdep_is_held(&table->tb6_lock));
key = (struct rt6key *)((u8 *)leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
if (!allow_create) {
if (replace_required) {
NL_SET_ERR_MSG(extack,
"Can not replace route - no match found");
pr_warn("Can't replace route, no match found\n");
return ERR_PTR(-ENOENT);
}
pr_warn("NLM_F_CREATE should be set when creating new route\n");
}
goto insert_above;
}
/*
* Exact match ?
*/
if (plen == fn->fn_bit) {
/* clean up an intermediate node */
if (!(fn->fn_flags & RTN_RTINFO)) {
RCU_INIT_POINTER(fn->leaf, NULL);
fib6_info_release(leaf);
/* remove null_entry in the root node */
} else if (fn->fn_flags & RTN_TL_ROOT &&
rcu_access_pointer(fn->leaf) ==
net->ipv6.fib6_null_entry) {
RCU_INIT_POINTER(fn->leaf, NULL);
}
return fn;
}
/*
* We have more bits to go
*/
/* Try to walk down on tree. */
dir = addr_bit_set(addr, fn->fn_bit);
pn = fn;
fn = dir ?
rcu_dereference_protected(fn->right,
lockdep_is_held(&table->tb6_lock)) :
rcu_dereference_protected(fn->left,
lockdep_is_held(&table->tb6_lock));
} while (fn);
if (!allow_create) {
/* We should not create new node because
* NLM_F_REPLACE was specified without NLM_F_CREATE
* I assume it is safe to require NLM_F_CREATE when
* REPLACE flag is used! Later we may want to remove the
* check for replace_required, because according
* to netlink specification, NLM_F_CREATE
* MUST be specified if new route is created.
* That would keep IPv6 consistent with IPv4
*/
if (replace_required) {
NL_SET_ERR_MSG(extack,
"Can not replace route - no match found");
pr_warn("Can't replace route, no match found\n");
return ERR_PTR(-ENOENT);
}
pr_warn("NLM_F_CREATE should be set when creating new route\n");
}
/*
* We walked to the bottom of tree.
* Create new leaf node without children.
*/
ln = node_alloc(net);
if (!ln)
return ERR_PTR(-ENOMEM);
ln->fn_bit = plen;
RCU_INIT_POINTER(ln->parent, pn);
if (dir)
rcu_assign_pointer(pn->right, ln);
else
rcu_assign_pointer(pn->left, ln);
return ln;
insert_above:
/*
* split since we don't have a common prefix anymore or
* we have a less significant route.
* we've to insert an intermediate node on the list
* this new node will point to the one we need to create
* and the current
*/
pn = rcu_dereference_protected(fn->parent,
lockdep_is_held(&table->tb6_lock));
/* find 1st bit in difference between the 2 addrs.
See comment in __ipv6_addr_diff: bit may be an invalid value,
but if it is >= plen, the value is ignored in any case.
*/
bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
/*
* (intermediate)[in]
* / \
* (new leaf node)[ln] (old node)[fn]
*/
if (plen > bit) {
in = node_alloc(net);
ln = node_alloc(net);
if (!in || !ln) {
if (in)
node_free_immediate(net, in);
if (ln)
node_free_immediate(net, ln);
return ERR_PTR(-ENOMEM);
}
/*
* new intermediate node.
* RTN_RTINFO will
* be off since that an address that chooses one of
* the branches would not match less specific routes
* in the other branch
*/
in->fn_bit = bit;
RCU_INIT_POINTER(in->parent, pn);
in->leaf = fn->leaf;
fib6_info_hold(rcu_dereference_protected(in->leaf,
lockdep_is_held(&table->tb6_lock)));
/* update parent pointer */
if (dir)
rcu_assign_pointer(pn->right, in);
else
rcu_assign_pointer(pn->left, in);
ln->fn_bit = plen;
RCU_INIT_POINTER(ln->parent, in);
rcu_assign_pointer(fn->parent, in);
if (addr_bit_set(addr, bit)) {
rcu_assign_pointer(in->right, ln);
rcu_assign_pointer(in->left, fn);
} else {
rcu_assign_pointer(in->left, ln);
rcu_assign_pointer(in->right, fn);
}
} else { /* plen <= bit */
/*
* (new leaf node)[ln]
* / \
* (old node)[fn] NULL
*/
ln = node_alloc(net);
if (!ln)
return ERR_PTR(-ENOMEM);
ln->fn_bit = plen;
RCU_INIT_POINTER(ln->parent, pn);
if (addr_bit_set(&key->addr, plen))
RCU_INIT_POINTER(ln->right, fn);
else
RCU_INIT_POINTER(ln->left, fn);
rcu_assign_pointer(fn->parent, ln);
if (dir)
rcu_assign_pointer(pn->right, ln);
else
rcu_assign_pointer(pn->left, ln);
}
return ln;
}
static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
const struct fib6_info *match,
const struct fib6_table *table)
{
int cpu;
if (!fib6_nh->rt6i_pcpu)
return;
/* release the reference to this fib entry from
* all of its cached pcpu routes
*/
for_each_possible_cpu(cpu) {
struct rt6_info **ppcpu_rt;
struct rt6_info *pcpu_rt;
ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
pcpu_rt = *ppcpu_rt;
/* only dropping the 'from' reference if the cached route
* is using 'match'. The cached pcpu_rt->from only changes
* from a fib6_info to NULL (ip6_dst_destroy); it can never
* change from one fib6_info reference to another
*/
if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
struct fib6_info *from;
from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
fib6_info_release(from);
}
}
}
struct fib6_nh_pcpu_arg {
struct fib6_info *from;
const struct fib6_table *table;
};
static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
{
struct fib6_nh_pcpu_arg *arg = _arg;
__fib6_drop_pcpu_from(nh, arg->from, arg->table);
return 0;
}
static void fib6_drop_pcpu_from(struct fib6_info *f6i,
const struct fib6_table *table)
{
/* Make sure rt6_make_pcpu_route() wont add other percpu routes
* while we are cleaning them here.
*/
f6i->fib6_destroying = 1;
mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
if (f6i->nh) {
struct fib6_nh_pcpu_arg arg = {
.from = f6i,
.table = table
};
nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from,
&arg);
} else {
struct fib6_nh *fib6_nh;
fib6_nh = f6i->fib6_nh;
__fib6_drop_pcpu_from(fib6_nh, f6i, table);
}
}
static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
struct net *net)
{
struct fib6_table *table = rt->fib6_table;
fib6_drop_pcpu_from(rt, table);
if (rt->nh && !list_empty(&rt->nh_list))
list_del_init(&rt->nh_list);
if (refcount_read(&rt->fib6_ref) != 1) {
/* This route is used as dummy address holder in some split
* nodes. It is not leaked, but it still holds other resources,
* which must be released in time. So, scan ascendant nodes
* and replace dummy references to this route with references
* to still alive ones.
*/
while (fn) {
struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
lockdep_is_held(&table->tb6_lock));
struct fib6_info *new_leaf;
if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
new_leaf = fib6_find_prefix(net, table, fn);
fib6_info_hold(new_leaf);
rcu_assign_pointer(fn->leaf, new_leaf);
fib6_info_release(rt);
}
fn = rcu_dereference_protected(fn->parent,
lockdep_is_held(&table->tb6_lock));
}
}
}
/*
* Insert routing information in a node.
*/
static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
struct nl_info *info,
struct netlink_ext_ack *extack)
{
struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
lockdep_is_held(&rt->fib6_table->tb6_lock));
struct fib6_info *iter = NULL;
struct fib6_info __rcu **ins;
struct fib6_info __rcu **fallback_ins = NULL;
int replace = (info->nlh &&
(info->nlh->nlmsg_flags & NLM_F_REPLACE));
int add = (!info->nlh ||
(info->nlh->nlmsg_flags & NLM_F_CREATE));
int found = 0;
bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
u16 nlflags = NLM_F_EXCL;
int err;
if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
nlflags |= NLM_F_APPEND;
ins = &fn->leaf;
for (iter = leaf; iter;
iter = rcu_dereference_protected(iter->fib6_next,
lockdep_is_held(&rt->fib6_table->tb6_lock))) {
/*
* Search for duplicates
*/
if (iter->fib6_metric == rt->fib6_metric) {
/*
* Same priority level
*/
if (info->nlh &&
(info->nlh->nlmsg_flags & NLM_F_EXCL))
return -EEXIST;
nlflags &= ~NLM_F_EXCL;
if (replace) {
if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
found++;
break;
}
if (rt_can_ecmp)
fallback_ins = fallback_ins ?: ins;
goto next_iter;
}
if (rt6_duplicate_nexthop(iter, rt)) {
if (rt->fib6_nsiblings)
rt->fib6_nsiblings = 0;
if (!(iter->fib6_flags & RTF_EXPIRES))
return -EEXIST;
if (!(rt->fib6_flags & RTF_EXPIRES))
fib6_clean_expires(iter);
else
fib6_set_expires(iter, rt->expires);
if (rt->fib6_pmtu)
fib6_metric_set(iter, RTAX_MTU,
rt->fib6_pmtu);
return -EEXIST;
}
/* If we have the same destination and the same metric,
* but not the same gateway, then the route we try to
* add is sibling to this route, increment our counter
* of siblings, and later we will add our route to the
* list.
* Only static routes (which don't have flag
* RTF_EXPIRES) are used for ECMPv6.
*
* To avoid long list, we only had siblings if the
* route have a gateway.
*/
if (rt_can_ecmp &&
rt6_qualify_for_ecmp(iter))
rt->fib6_nsiblings++;
}
if (iter->fib6_metric > rt->fib6_metric)
break;
next_iter:
ins = &iter->fib6_next;
}
if (fallback_ins && !found) {
/* No ECMP-able route found, replace first non-ECMP one */
ins = fallback_ins;
iter = rcu_dereference_protected(*ins,
lockdep_is_held(&rt->fib6_table->tb6_lock));
found++;
}
/* Reset round-robin state, if necessary */
if (ins == &fn->leaf)
fn->rr_ptr = NULL;
/* Link this route to others same route. */
if (rt->fib6_nsiblings) {
unsigned int fib6_nsiblings;
struct fib6_info *sibling, *temp_sibling;
/* Find the first route that have the same metric */
sibling = leaf;
while (sibling) {
if (sibling->fib6_metric == rt->fib6_metric &&
rt6_qualify_for_ecmp(sibling)) {
list_add_tail(&rt->fib6_siblings,
&sibling->fib6_siblings);
break;
}
sibling = rcu_dereference_protected(sibling->fib6_next,
lockdep_is_held(&rt->fib6_table->tb6_lock));
}
/* For each sibling in the list, increment the counter of
* siblings. BUG() if counters does not match, list of siblings
* is broken!
*/
fib6_nsiblings = 0;
list_for_each_entry_safe(sibling, temp_sibling,
&rt->fib6_siblings, fib6_siblings) {
sibling->fib6_nsiblings++;
BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
fib6_nsiblings++;
}
BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
rt6_multipath_rebalance(temp_sibling);
}
/*
* insert node
*/
if (!replace) {
if (!add)
pr_warn("NLM_F_CREATE should be set when creating new route\n");
add:
nlflags |= NLM_F_CREATE;
if (!info->skip_notify_kernel) {
err = call_fib6_entry_notifiers(info->nl_net,
FIB_EVENT_ENTRY_ADD,
rt, extack);
if (err) {
struct fib6_info *sibling, *next_sibling;
/* If the route has siblings, then it first
* needs to be unlinked from them.
*/
if (!rt->fib6_nsiblings)
return err;
list_for_each_entry_safe(sibling, next_sibling,
&rt->fib6_siblings,
fib6_siblings)
sibling->fib6_nsiblings--;
rt->fib6_nsiblings = 0;
list_del_init(&rt->fib6_siblings);
rt6_multipath_rebalance(next_sibling);
return err;
}
}
rcu_assign_pointer(rt->fib6_next, iter);
fib6_info_hold(rt);
rcu_assign_pointer(rt->fib6_node, fn);
rcu_assign_pointer(*ins, rt);
if (!info->skip_notify)
inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
if (!(fn->fn_flags & RTN_RTINFO)) {
info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
fn->fn_flags |= RTN_RTINFO;
}
} else {
int nsiblings;
if (!found) {
if (add)
goto add;
pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
return -ENOENT;
}
if (!info->skip_notify_kernel) {
err = call_fib6_entry_notifiers(info->nl_net,
FIB_EVENT_ENTRY_REPLACE,
rt, extack);
if (err)
return err;
}
fib6_info_hold(rt);
rcu_assign_pointer(rt->fib6_node, fn);
rt->fib6_next = iter->fib6_next;
rcu_assign_pointer(*ins, rt);
if (!info->skip_notify)
inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
if (!(fn->fn_flags & RTN_RTINFO)) {
info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
fn->fn_flags |= RTN_RTINFO;
}
nsiblings = iter->fib6_nsiblings;
iter->fib6_node = NULL;
fib6_purge_rt(iter, fn, info->nl_net);
if (rcu_access_pointer(fn->rr_ptr) == iter)
fn->rr_ptr = NULL;
fib6_info_release(iter);
if (nsiblings) {
/* Replacing an ECMP route, remove all siblings */
ins = &rt->fib6_next;
iter = rcu_dereference_protected(*ins,
lockdep_is_held(&rt->fib6_table->tb6_lock));
while (iter) {
if (iter->fib6_metric > rt->fib6_metric)
break;
if (rt6_qualify_for_ecmp(iter)) {
*ins = iter->fib6_next;
iter->fib6_node = NULL;
fib6_purge_rt(iter, fn, info->nl_net);
if (rcu_access_pointer(fn->rr_ptr) == iter)
fn->rr_ptr = NULL;
fib6_info_release(iter);
nsiblings--;
info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
} else {
ins = &iter->fib6_next;
}
iter = rcu_dereference_protected(*ins,
lockdep_is_held(&rt->fib6_table->tb6_lock));
}
WARN_ON(nsiblings != 0);
}
}
return 0;
}
static void fib6_start_gc(struct net *net, struct fib6_info *rt)
{
if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
(rt->fib6_flags & RTF_EXPIRES))
mod_timer(&net->ipv6.ip6_fib_timer,
jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
}
void fib6_force_start_gc(struct net *net)
{
if (!timer_pending(&net->ipv6.ip6_fib_timer))
mod_timer(&net->ipv6.ip6_fib_timer,
jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
}
static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
int sernum)
{
struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
lockdep_is_held(&rt->fib6_table->tb6_lock));
/* paired with smp_rmb() in rt6_get_cookie_safe() */
smp_wmb();
while (fn) {
fn->fn_sernum = sernum;
fn = rcu_dereference_protected(fn->parent,
lockdep_is_held(&rt->fib6_table->tb6_lock));
}
}
void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
{
__fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
}
/* allow ipv4 to update sernum via ipv6_stub */
void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
{
spin_lock_bh(&f6i->fib6_table->tb6_lock);
fib6_update_sernum_upto_root(net, f6i);
spin_unlock_bh(&f6i->fib6_table->tb6_lock);
}
/*
* Add routing information to the routing tree.
* <destination addr>/<source addr>
* with source addr info in sub-trees
* Need to own table->tb6_lock
*/
int fib6_add(struct fib6_node *root, struct fib6_info *rt,
struct nl_info *info, struct netlink_ext_ack *extack)
{
struct fib6_table *table = rt->fib6_table;
struct fib6_node *fn, *pn = NULL;
int err = -ENOMEM;
int allow_create = 1;
int replace_required = 0;
int sernum = fib6_new_sernum(info->nl_net);
if (info->nlh) {
if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
allow_create = 0;
if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
replace_required = 1;
}
if (!allow_create && !replace_required)
pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
fn = fib6_add_1(info->nl_net, table, root,
&rt->fib6_dst.addr, rt->fib6_dst.plen,
offsetof(struct fib6_info, fib6_dst), allow_create,
replace_required, extack);
if (IS_ERR(fn)) {
err = PTR_ERR(fn);
fn = NULL;
goto out;
}
pn = fn;
#ifdef CONFIG_IPV6_SUBTREES
if (rt->fib6_src.plen) {
struct fib6_node *sn;
if (!rcu_access_pointer(fn->subtree)) {
struct fib6_node *sfn;
/*
* Create subtree.
*
* fn[main tree]
* |
* sfn[subtree root]
* \
* sn[new leaf node]
*/
/* Create subtree root node */
sfn = node_alloc(info->nl_net);
if (!sfn)
goto failure;
fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
rcu_assign_pointer(sfn->leaf,
info->nl_net->ipv6.fib6_null_entry);
sfn->fn_flags = RTN_ROOT;
/* Now add the first leaf node to new subtree */
sn = fib6_add_1(info->nl_net, table, sfn,
&rt->fib6_src.addr, rt->fib6_src.plen,
offsetof(struct fib6_info, fib6_src),
allow_create, replace_required, extack);
if (IS_ERR(sn)) {
/* If it is failed, discard just allocated
root, and then (in failure) stale node
in main tree.
*/
node_free_immediate(info->nl_net, sfn);
err = PTR_ERR(sn);
goto failure;
}
/* Now link new subtree to main tree */
rcu_assign_pointer(sfn->parent, fn);
rcu_assign_pointer(fn->subtree, sfn);
} else {
sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
&rt->fib6_src.addr, rt->fib6_src.plen,
offsetof(struct fib6_info, fib6_src),
allow_create, replace_required, extack);
if (IS_ERR(sn)) {
err = PTR_ERR(sn);
goto failure;
}
}
if (!rcu_access_pointer(fn->leaf)) {
if (fn->fn_flags & RTN_TL_ROOT) {
/* put back null_entry for root node */
rcu_assign_pointer(fn->leaf,
info->nl_net->ipv6.fib6_null_entry);
} else {
fib6_info_hold(rt);
rcu_assign_pointer(fn->leaf, rt);
}
}
fn = sn;
}
#endif
err = fib6_add_rt2node(fn, rt, info, extack);
if (!err) {
if (rt->nh)
list_add(&rt->nh_list, &rt->nh->f6i_list);
__fib6_update_sernum_upto_root(rt, sernum);
fib6_start_gc(info->nl_net, rt);
}
out:
if (err) {
#ifdef CONFIG_IPV6_SUBTREES
/*
* If fib6_add_1 has cleared the old leaf pointer in the
* super-tree leaf node we have to find a new one for it.
*/
if (pn != fn) {
struct fib6_info *pn_leaf =
rcu_dereference_protected(pn->leaf,
lockdep_is_held(&table->tb6_lock));
if (pn_leaf == rt) {
pn_leaf = NULL;
RCU_INIT_POINTER(pn->leaf, NULL);
fib6_info_release(rt);
}
if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
pn_leaf = fib6_find_prefix(info->nl_net, table,
pn);
#if RT6_DEBUG >= 2
if (!pn_leaf) {
WARN_ON(!pn_leaf);
pn_leaf =
info->nl_net->ipv6.fib6_null_entry;
}
#endif
fib6_info_hold(pn_leaf);
rcu_assign_pointer(pn->leaf, pn_leaf);
}
}
#endif
goto failure;
} else if (fib6_requires_src(rt)) {
fib6_routes_require_src_inc(info->nl_net);
}
return err;
failure:
/* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
* 1. fn is an intermediate node and we failed to add the new
* route to it in both subtree creation failure and fib6_add_rt2node()
* failure case.
* 2. fn is the root node in the table and we fail to add the first
* default route to it.
*/
if (fn &&
(!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
(fn->fn_flags & RTN_TL_ROOT &&
!rcu_access_pointer(fn->leaf))))
fib6_repair_tree(info->nl_net, table, fn);
return err;
}
/*
* Routing tree lookup
*
*/
struct lookup_args {
int offset; /* key offset on fib6_info */
const struct in6_addr *addr; /* search key */
};
static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
struct lookup_args *args)
{
struct fib6_node *fn;
__be32 dir;
if (unlikely(args->offset == 0))
return NULL;
/*
* Descend on a tree
*/
fn = root;
for (;;) {
struct fib6_node *next;
dir = addr_bit_set(args->addr, fn->fn_bit);
next = dir ? rcu_dereference(fn->right) :
rcu_dereference(fn->left);
if (next) {
fn = next;
continue;
}
break;
}
while (fn) {
struct fib6_node *subtree = FIB6_SUBTREE(fn);
if (subtree || fn->fn_flags & RTN_RTINFO) {
struct fib6_info *leaf = rcu_dereference(fn->leaf);
struct rt6key *key;
if (!leaf)
goto backtrack;
key = (struct rt6key *) ((u8 *)leaf + args->offset);
if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
#ifdef CONFIG_IPV6_SUBTREES
if (subtree) {
struct fib6_node *sfn;
sfn = fib6_node_lookup_1(subtree,
args + 1);
if (!sfn)
goto backtrack;
fn = sfn;
}
#endif
if (fn->fn_flags & RTN_RTINFO)
return fn;
}
}
backtrack:
if (fn->fn_flags & RTN_ROOT)
break;
fn = rcu_dereference(fn->parent);
}
return NULL;
}
/* called with rcu_read_lock() held
*/
struct fib6_node *fib6_node_lookup(struct fib6_node *root,
const struct in6_addr *daddr,
const struct in6_addr *saddr)
{
struct fib6_node *fn;
struct lookup_args args[] = {
{
.offset = offsetof(struct fib6_info, fib6_dst),
.addr = daddr,
},
#ifdef CONFIG_IPV6_SUBTREES
{
.offset = offsetof(struct fib6_info, fib6_src),
.addr = saddr,
},
#endif
{
.offset = 0, /* sentinel */
}
};
fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
if (!fn || fn->fn_flags & RTN_TL_ROOT)
fn = root;
return fn;
}
/*
* Get node with specified destination prefix (and source prefix,
* if subtrees are used)
* exact_match == true means we try to find fn with exact match of
* the passed in prefix addr
* exact_match == false means we try to find fn with longest prefix
* match of the passed in prefix addr. This is useful for finding fn
* for cached route as it will be stored in the exception table under
* the node with longest prefix length.
*/
static struct fib6_node *fib6_locate_1(struct fib6_node *root,
const struct in6_addr *addr,
int plen, int offset,
bool exact_match)
{
struct fib6_node *fn, *prev = NULL;
for (fn = root; fn ; ) {
struct fib6_info *leaf = rcu_dereference(fn->leaf);
struct rt6key *key;
/* This node is being deleted */
if (!leaf) {
if (plen <= fn->fn_bit)
goto out;
else
goto next;
}
key = (struct rt6key *)((u8 *)leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
goto out;
if (plen == fn->fn_bit)
return fn;
if (fn->fn_flags & RTN_RTINFO)
prev = fn;
next:
/*
* We have more bits to go
*/
if (addr_bit_set(addr, fn->fn_bit))
fn = rcu_dereference(fn->right);
else
fn = rcu_dereference(fn->left);
}
out:
if (exact_match)
return NULL;
else
return prev;
}
struct fib6_node *fib6_locate(struct fib6_node *root,
const struct in6_addr *daddr, int dst_len,
const struct in6_addr *saddr, int src_len,
bool exact_match)
{
struct fib6_node *fn;
fn = fib6_locate_1(root, daddr, dst_len,
offsetof(struct fib6_info, fib6_dst),
exact_match);
#ifdef CONFIG_IPV6_SUBTREES
if (src_len) {
WARN_ON(saddr == NULL);
if (fn) {
struct fib6_node *subtree = FIB6_SUBTREE(fn);
if (subtree) {
fn = fib6_locate_1(subtree, saddr, src_len,
offsetof(struct fib6_info, fib6_src),
exact_match);
}
}
}
#endif
if (fn && fn->fn_flags & RTN_RTINFO)
return fn;
return NULL;
}
/*
* Deletion
*
*/
static struct fib6_info *fib6_find_prefix(struct net *net,
struct fib6_table *table,
struct fib6_node *fn)
{
struct fib6_node *child_left, *child_right;
if (fn->fn_flags & RTN_ROOT)
return net->ipv6.fib6_null_entry;
while (fn) {
child_left = rcu_dereference_protected(fn->left,
lockdep_is_held(&table->tb6_lock));
child_right = rcu_dereference_protected(fn->right,
lockdep_is_held(&table->tb6_lock));
if (child_left)
return rcu_dereference_protected(child_left->leaf,
lockdep_is_held(&table->tb6_lock));
if (child_right)
return rcu_dereference_protected(child_right->leaf,
lockdep_is_held(&table->tb6_lock));
fn = FIB6_SUBTREE(fn);
}
return NULL;
}
/*
* Called to trim the tree of intermediate nodes when possible. "fn"
* is the node we want to try and remove.
* Need to own table->tb6_lock
*/
static struct fib6_node *fib6_repair_tree(struct net *net,
struct fib6_table *table,
struct fib6_node *fn)
{
int children;
int nstate;
struct fib6_node *child;
struct fib6_walker *w;
int iter = 0;
/* Set fn->leaf to null_entry for root node. */
if (fn->fn_flags & RTN_TL_ROOT) {
rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
return fn;
}
for (;;) {
struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
lockdep_is_held(&table->tb6_lock));
struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
lockdep_is_held(&table->tb6_lock));
struct fib6_node *pn = rcu_dereference_protected(fn->parent,
lockdep_is_held(&table->tb6_lock));
struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
lockdep_is_held(&table->tb6_lock));
struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
lockdep_is_held(&table->tb6_lock));
struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
lockdep_is_held(&table->tb6_lock));
struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
lockdep_is_held(&table->tb6_lock));
struct fib6_info *new_fn_leaf;
RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
iter++;
WARN_ON(fn->fn_flags & RTN_RTINFO);
WARN_ON(fn->fn_flags & RTN_TL_ROOT);
WARN_ON(fn_leaf);
children = 0;
child = NULL;
if (fn_r)
child = fn_r, children |= 1;
if (fn_l)
child = fn_l, children |= 2;
if (children == 3 || FIB6_SUBTREE(fn)
#ifdef CONFIG_IPV6_SUBTREES
/* Subtree root (i.e. fn) may have one child */
|| (children && fn->fn_flags & RTN_ROOT)
#endif
) {
new_fn_leaf = fib6_find_prefix(net, table, fn);
#if RT6_DEBUG >= 2
if (!new_fn_leaf) {
WARN_ON(!new_fn_leaf);
new_fn_leaf = net->ipv6.fib6_null_entry;
}
#endif
fib6_info_hold(new_fn_leaf);
rcu_assign_pointer(fn->leaf, new_fn_leaf);
return pn;
}
#ifdef CONFIG_IPV6_SUBTREES
if (FIB6_SUBTREE(pn) == fn) {
WARN_ON(!(fn->fn_flags & RTN_ROOT));
RCU_INIT_POINTER(pn->subtree, NULL);
nstate = FWS_L;
} else {
WARN_ON(fn->fn_flags & RTN_ROOT);
#endif
if (pn_r == fn)
rcu_assign_pointer(pn->right, child);
else if (pn_l == fn)
rcu_assign_pointer(pn->left, child);
#if RT6_DEBUG >= 2
else
WARN_ON(1);
#endif
if (child)
rcu_assign_pointer(child->parent, pn);
nstate = FWS_R;
#ifdef CONFIG_IPV6_SUBTREES
}
#endif
read_lock(&net->ipv6.fib6_walker_lock);
FOR_WALKERS(net, w) {
if (!child) {
if (w->node == fn) {
RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
w->node = pn;
w->state = nstate;
}
} else {
if (w->node == fn) {
w->node = child;
if (children&2) {
RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
} else {
RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
}
}
}
}
read_unlock(&net->ipv6.fib6_walker_lock);
node_free(net, fn);
if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
return pn;
RCU_INIT_POINTER(pn->leaf, NULL);
fib6_info_release(pn_leaf);
fn = pn;
}
}
static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
struct fib6_info __rcu **rtp, struct nl_info *info)
{
struct fib6_walker *w;
struct fib6_info *rt = rcu_dereference_protected(*rtp,
lockdep_is_held(&table->tb6_lock));
struct net *net = info->nl_net;
RT6_TRACE("fib6_del_route\n");
/* Unlink it */
*rtp = rt->fib6_next;
rt->fib6_node = NULL;
net->ipv6.rt6_stats->fib_rt_entries--;
net->ipv6.rt6_stats->fib_discarded_routes++;
/* Flush all cached dst in exception table */
rt6_flush_exceptions(rt);
/* Reset round-robin state, if necessary */
if (rcu_access_pointer(fn->rr_ptr) == rt)
fn->rr_ptr = NULL;
/* Remove this entry from other siblings */
if (rt->fib6_nsiblings) {
struct fib6_info *sibling, *next_sibling;
list_for_each_entry_safe(sibling, next_sibling,
&rt->fib6_siblings, fib6_siblings)
sibling->fib6_nsiblings--;
rt->fib6_nsiblings = 0;
list_del_init(&rt->fib6_siblings);
rt6_multipath_rebalance(next_sibling);
}
/* Adjust walkers */
read_lock(&net->ipv6.fib6_walker_lock);
FOR_WALKERS(net, w) {
if (w->state == FWS_C && w->leaf == rt) {
RT6_TRACE("walker %p adjusted by delroute\n", w);
w->leaf = rcu_dereference_protected(rt->fib6_next,
lockdep_is_held(&table->tb6_lock));
if (!w->leaf)
w->state = FWS_U;
}
}
read_unlock(&net->ipv6.fib6_walker_lock);
/* If it was last route, call fib6_repair_tree() to:
* 1. For root node, put back null_entry as how the table was created.
* 2. For other nodes, expunge its radix tree node.
*/
if (!rcu_access_pointer(fn->leaf)) {
if (!(fn->fn_flags & RTN_TL_ROOT)) {
fn->fn_flags &= ~RTN_RTINFO;
net->ipv6.rt6_stats->fib_route_nodes--;
}
fn = fib6_repair_tree(net, table, fn);
}
fib6_purge_rt(rt, fn, net);
if (!info->skip_notify_kernel)
call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
if (!info->skip_notify)
inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
fib6_info_release(rt);
}
/* Need to own table->tb6_lock */
int fib6_del(struct fib6_info *rt, struct nl_info *info)
{
struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
lockdep_is_held(&rt->fib6_table->tb6_lock));
struct fib6_table *table = rt->fib6_table;
struct net *net = info->nl_net;
struct fib6_info __rcu **rtp;
struct fib6_info __rcu **rtp_next;
if (!fn || rt == net->ipv6.fib6_null_entry)
return -ENOENT;
WARN_ON(!(fn->fn_flags & RTN_RTINFO));
/*
* Walk the leaf entries looking for ourself
*/
for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
struct fib6_info *cur = rcu_dereference_protected(*rtp,
lockdep_is_held(&table->tb6_lock));
if (rt == cur) {
if (fib6_requires_src(cur))
fib6_routes_require_src_dec(info->nl_net);
fib6_del_route(table, fn, rtp, info);
return 0;
}
rtp_next = &cur->fib6_next;
}
return -ENOENT;
}
/*
* Tree traversal function.
*
* Certainly, it is not interrupt safe.
* However, it is internally reenterable wrt itself and fib6_add/fib6_del.
* It means, that we can modify tree during walking
* and use this function for garbage collection, clone pruning,
* cleaning tree when a device goes down etc. etc.
*
* It guarantees that every node will be traversed,
* and that it will be traversed only once.
*
* Callback function w->func may return:
* 0 -> continue walking.
* positive value -> walking is suspended (used by tree dumps,
* and probably by gc, if it will be split to several slices)
* negative value -> terminate walking.
*
* The function itself returns:
* 0 -> walk is complete.
* >0 -> walk is incomplete (i.e. suspended)
* <0 -> walk is terminated by an error.
*
* This function is called with tb6_lock held.
*/
static int fib6_walk_continue(struct fib6_walker *w)
{
struct fib6_node *fn, *pn, *left, *right;
/* w->root should always be table->tb6_root */
WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
for (;;) {
fn = w->node;
if (!fn)
return 0;
switch (w->state) {
#ifdef CONFIG_IPV6_SUBTREES
case FWS_S:
if (FIB6_SUBTREE(fn)) {
w->node = FIB6_SUBTREE(fn);
continue;
}
w->state = FWS_L;
#endif
/* fall through */
case FWS_L:
left = rcu_dereference_protected(fn->left, 1);
if (left) {
w->node = left;
w->state = FWS_INIT;
continue;
}
w->state = FWS_R;
/* fall through */
case FWS_R:
right = rcu_dereference_protected(fn->right, 1);
if (right) {
w->node = right;
w->state = FWS_INIT;
continue;
}
w->state = FWS_C;
w->leaf = rcu_dereference_protected(fn->leaf, 1);
/* fall through */
case FWS_C:
if (w->leaf && fn->fn_flags & RTN_RTINFO) {
int err;
if (w->skip) {
w->skip--;
goto skip;
}
err = w->func(w);
if (err)
return err;
w->count++;
continue;
}
skip:
w->state = FWS_U;
/* fall through */
case FWS_U:
if (fn == w->root)
return 0;
pn = rcu_dereference_protected(fn->parent, 1);
left = rcu_dereference_protected(pn->left, 1);
right = rcu_dereference_protected(pn->right, 1);
w->node = pn;
#ifdef CONFIG_IPV6_SUBTREES
if (FIB6_SUBTREE(pn) == fn) {
WARN_ON(!(fn->fn_flags & RTN_ROOT));
w->state = FWS_L;
continue;
}
#endif
if (left == fn) {
w->state = FWS_R;
continue;
}
if (right == fn) {
w->state = FWS_C;
w->leaf = rcu_dereference_protected(w->node->leaf, 1);
continue;
}
#if RT6_DEBUG >= 2
WARN_ON(1);
#endif
}
}
}
static int fib6_walk(struct net *net, struct fib6_walker *w)
{
int res;
w->state = FWS_INIT;
w->node = w->root;
fib6_walker_link(net, w);
res = fib6_walk_continue(w);
if (res <= 0)
fib6_walker_unlink(net, w);
return res;
}
static int fib6_clean_node(struct fib6_walker *w)
{
int res;
struct fib6_info *rt;
struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
struct nl_info info = {
.nl_net = c->net,
.skip_notify = c->skip_notify,
};
if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
w->node->fn_sernum != c->sernum)
w->node->fn_sernum = c->sernum;
if (!c->func) {
WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
w->leaf = NULL;
return 0;
}
for_each_fib6_walker_rt(w) {
res = c->func(rt, c->arg);
if (res == -1) {
w->leaf = rt;
res = fib6_del(rt, &info);
if (res) {
#if RT6_DEBUG >= 2
pr_debug("%s: del failed: rt=%p@%p err=%d\n",
__func__, rt,
rcu_access_pointer(rt->fib6_node),
res);
#endif
continue;
}
return 0;
} else if (res == -2) {
if (WARN_ON(!rt->fib6_nsiblings))
continue;
rt = list_last_entry(&rt->fib6_siblings,
struct fib6_info, fib6_siblings);
continue;
}
WARN_ON(res != 0);
}
w->leaf = rt;
return 0;
}
/*
* Convenient frontend to tree walker.
*
* func is called on each route.
* It may return -2 -> skip multipath route.
* -1 -> delete this route.
* 0 -> continue walking
*/
static void fib6_clean_tree(struct net *net, struct fib6_node *root,
int (*func)(struct fib6_info *, void *arg),
int sernum, void *arg, bool skip_notify)
{
struct fib6_cleaner c;
c.w.root = root;
c.w.func = fib6_clean_node;
c.w.count = 0;
c.w.skip = 0;
c.w.skip_in_node = 0;
c.func = func;
c.sernum = sernum;
c.arg = arg;
c.net = net;
c.skip_notify = skip_notify;
fib6_walk(net, &c.w);
}
static void __fib6_clean_all(struct net *net,
int (*func)(struct fib6_info *, void *),
int sernum, void *arg, bool skip_notify)
{
struct fib6_table *table;
struct hlist_head *head;
unsigned int h;
rcu_read_lock();
for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
head = &net->ipv6.fib_table_hash[h];
hlist_for_each_entry_rcu(table, head, tb6_hlist) {
spin_lock_bh(&table->tb6_lock);
fib6_clean_tree(net, &table->tb6_root,
func, sernum, arg, skip_notify);
spin_unlock_bh(&table->tb6_lock);
}
}
rcu_read_unlock();
}
void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
void *arg)
{
__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
}
void fib6_clean_all_skip_notify(struct net *net,
int (*func)(struct fib6_info *, void *),
void *arg)
{
__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
}
static void fib6_flush_trees(struct net *net)
{
int new_sernum = fib6_new_sernum(net);
__fib6_clean_all(net, NULL, new_sernum, NULL, false);
}
/*
* Garbage collection
*/
static int fib6_age(struct fib6_info *rt, void *arg)
{
struct fib6_gc_args *gc_args = arg;
unsigned long now = jiffies;
/*
* check addrconf expiration here.
* Routes are expired even if they are in use.
*/
if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
if (time_after(now, rt->expires)) {
RT6_TRACE("expiring %p\n", rt);
return -1;
}
gc_args->more++;
}
/* Also age clones in the exception table.
* Note, that clones are aged out
* only if they are not in use now.
*/
rt6_age_exceptions(rt, gc_args, now);
return 0;
}
void fib6_run_gc(unsigned long expires, struct net *net, bool force)
{
struct fib6_gc_args gc_args;
unsigned long now;
if (force) {
spin_lock_bh(&net->ipv6.fib6_gc_lock);
} else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
return;
}
gc_args.timeout = expires ? (int)expires :
net->ipv6.sysctl.ip6_rt_gc_interval;
gc_args.more = 0;
fib6_clean_all(net, fib6_age, &gc_args);
now = jiffies;
net->ipv6.ip6_rt_last_gc = now;
if (gc_args.more)
mod_timer(&net->ipv6.ip6_fib_timer,
round_jiffies(now
+ net->ipv6.sysctl.ip6_rt_gc_interval));
else
del_timer(&net->ipv6.ip6_fib_timer);
spin_unlock_bh(&net->ipv6.fib6_gc_lock);
}
static void fib6_gc_timer_cb(struct timer_list *t)
{
struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
fib6_run_gc(0, arg, true);
}
static int __net_init fib6_net_init(struct net *net)
{
size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
int err;
err = fib6_notifier_init(net);
if (err)
return err;
spin_lock_init(&net->ipv6.fib6_gc_lock);
rwlock_init(&net->ipv6.fib6_walker_lock);
INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
if (!net->ipv6.rt6_stats)
goto out_timer;
/* Avoid false sharing : Use at least a full cache line */
size = max_t(size_t, size, L1_CACHE_BYTES);
net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
if (!net->ipv6.fib_table_hash)
goto out_rt6_stats;
net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
GFP_KERNEL);
if (!net->ipv6.fib6_main_tbl)
goto out_fib_table_hash;
net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
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);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
GFP_KERNEL);
if (!net->ipv6.fib6_local_tbl)
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.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);
#endif
fib6_tables_init(net);
return 0;
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
out_fib6_main_tbl:
kfree(net->ipv6.fib6_main_tbl);
#endif
out_fib_table_hash:
kfree(net->ipv6.fib_table_hash);
out_rt6_stats:
kfree(net->ipv6.rt6_stats);
out_timer:
fib6_notifier_exit(net);
return -ENOMEM;
}
static void fib6_net_exit(struct net *net)
{
unsigned int i;
del_timer_sync(&net->ipv6.ip6_fib_timer);
for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
struct hlist_head *head = &net->ipv6.fib_table_hash[i];
struct hlist_node *tmp;
struct fib6_table *tb;
hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
hlist_del(&tb->tb6_hlist);
fib6_free_table(tb);
}
}
kfree(net->ipv6.fib_table_hash);
kfree(net->ipv6.rt6_stats);
fib6_notifier_exit(net);
}
static struct pernet_operations fib6_net_ops = {
.init = fib6_net_init,
.exit = fib6_net_exit,
};
int __init fib6_init(void)
{
int ret = -ENOMEM;
fib6_node_kmem = kmem_cache_create("fib6_nodes",
sizeof(struct fib6_node),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (!fib6_node_kmem)
goto out;
ret = register_pernet_subsys(&fib6_net_ops);
if (ret)
goto out_kmem_cache_create;
ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
inet6_dump_fib, 0);
if (ret)
goto out_unregister_subsys;
__fib6_flush_trees = fib6_flush_trees;
out:
return ret;
out_unregister_subsys:
unregister_pernet_subsys(&fib6_net_ops);
out_kmem_cache_create:
kmem_cache_destroy(fib6_node_kmem);
goto out;
}
void fib6_gc_cleanup(void)
{
unregister_pernet_subsys(&fib6_net_ops);
kmem_cache_destroy(fib6_node_kmem);
}
#ifdef CONFIG_PROC_FS
static int ipv6_route_seq_show(struct seq_file *seq, void *v)
{
struct fib6_info *rt = v;
struct ipv6_route_iter *iter = seq->private;
struct fib6_nh *fib6_nh = rt->fib6_nh;
unsigned int flags = rt->fib6_flags;
const struct net_device *dev;
if (rt->nh)
fib6_nh = nexthop_fib6_nh(rt->nh);
seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
#ifdef CONFIG_IPV6_SUBTREES
seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
#else
seq_puts(seq, "00000000000000000000000000000000 00 ");
#endif
if (fib6_nh->fib_nh_gw_family) {
flags |= RTF_GATEWAY;
seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6);
} else {
seq_puts(seq, "00000000000000000000000000000000");
}
dev = fib6_nh->fib_nh_dev;
seq_printf(seq, " %08x %08x %08x %08x %8s\n",
rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
flags, dev ? dev->name : "");
iter->w.leaf = NULL;
return 0;
}
static int ipv6_route_yield(struct fib6_walker *w)
{
struct ipv6_route_iter *iter = w->args;
if (!iter->skip)
return 1;
do {
iter->w.leaf = rcu_dereference_protected(
iter->w.leaf->fib6_next,
lockdep_is_held(&iter->tbl->tb6_lock));
iter->skip--;
if (!iter->skip && iter->w.leaf)
return 1;
} while (iter->w.leaf);
return 0;
}
static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
struct net *net)
{
memset(&iter->w, 0, sizeof(iter->w));
iter->w.func = ipv6_route_yield;
iter->w.root = &iter->tbl->tb6_root;
iter->w.state = FWS_INIT;
iter->w.node = iter->w.root;
iter->w.args = iter;
iter->sernum = iter->w.root->fn_sernum;
INIT_LIST_HEAD(&iter->w.lh);
fib6_walker_link(net, &iter->w);
}
static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
struct net *net)
{
unsigned int h;
struct hlist_node *node;
if (tbl) {
h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
} else {
h = 0;
node = NULL;
}
while (!node && h < FIB6_TABLE_HASHSZ) {
node = rcu_dereference_bh(
hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
}
return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
}
static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
{
if (iter->sernum != iter->w.root->fn_sernum) {
iter->sernum = iter->w.root->fn_sernum;
iter->w.state = FWS_INIT;
iter->w.node = iter->w.root;
WARN_ON(iter->w.skip);
iter->w.skip = iter->w.count;
}
}
static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
int r;
struct fib6_info *n;
struct net *net = seq_file_net(seq);
struct ipv6_route_iter *iter = seq->private;
if (!v)
goto iter_table;
n = rcu_dereference_bh(((struct fib6_info *)v)->fib6_next);
if (n) {
++*pos;
return n;
}
iter_table:
ipv6_route_check_sernum(iter);
spin_lock_bh(&iter->tbl->tb6_lock);
r = fib6_walk_continue(&iter->w);
spin_unlock_bh(&iter->tbl->tb6_lock);
if (r > 0) {
if (v)
++*pos;
return iter->w.leaf;
} else if (r < 0) {
fib6_walker_unlink(net, &iter->w);
return NULL;
}
fib6_walker_unlink(net, &iter->w);
iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
if (!iter->tbl)
return NULL;
ipv6_route_seq_setup_walk(iter, net);
goto iter_table;
}
static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU_BH)
{
struct net *net = seq_file_net(seq);
struct ipv6_route_iter *iter = seq->private;
rcu_read_lock_bh();
iter->tbl = ipv6_route_seq_next_table(NULL, net);
iter->skip = *pos;
if (iter->tbl) {
ipv6_route_seq_setup_walk(iter, net);
return ipv6_route_seq_next(seq, NULL, pos);
} else {
return NULL;
}
}
static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
{
struct fib6_walker *w = &iter->w;
return w->node && !(w->state == FWS_U && w->node == w->root);
}
static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
__releases(RCU_BH)
{
struct net *net = seq_file_net(seq);
struct ipv6_route_iter *iter = seq->private;
if (ipv6_route_iter_active(iter))
fib6_walker_unlink(net, &iter->w);
rcu_read_unlock_bh();
}
const struct seq_operations ipv6_route_seq_ops = {
.start = ipv6_route_seq_start,
.next = ipv6_route_seq_next,
.stop = ipv6_route_seq_stop,
.show = ipv6_route_seq_show
};
#endif /* CONFIG_PROC_FS */
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