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bf9a8a061d
linux/net/ipv6/ip6_fib.c
Stefano Brivio bf9a8a061d ipv6/route: Change return code of rt6_dump_route() for partial node dumps 
In the next patch, we are going to add optional dump of exceptions to
rt6_dump_route().

Change the return code of rt6_dump_route() to accomodate partial node
dumps: we might dump multiple routes per node, and might be able to dump
only a given number of them, so fib6_dump_node() will need to know how
many routes have been dumped on partial dump, to restart the dump from the
point where it was interrupted.

Note that fib6_dump_node() is the only caller and already handles all
non-negative return codes as success: those become -1 to signal that we're
done with the node. If we fail, return 0, as we were unable to dump the
single route in the node, but we're not done with it.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-24 10:18:49 -07:00

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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, struct net *net,
enum fib_event_type event_type,
struct fib6_info *rt)
{
struct fib6_entry_notifier_info info = {
.rt = rt,
};
return call_fib6_notifier(nb, net, 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;
};
static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
{
if (rt == arg->net->ipv6.fib6_null_entry)
return;
call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
}
static int fib6_node_dump(struct fib6_walker *w)
{
struct fib6_info *rt;
for_each_fib6_walker_rt(w)
fib6_rt_dump(rt, w->args);
w->leaf = NULL;
return 0;
}
static void fib6_table_dump(struct net *net, struct fib6_table *tb,
struct fib6_walker *w)
{
w->root = &tb->tb6_root;
spin_lock_bh(&tb->tb6_lock);
fib6_walk(net, w);
spin_unlock_bh(&tb->tb6_lock);
}
/* Called with rcu_read_lock() */
int fib6_tables_dump(struct net *net, struct notifier_block *nb)
{
struct fib6_dump_arg arg;
struct fib6_walker *w;
unsigned int h;
w = kzalloc(sizeof(*w), GFP_ATOMIC);
if (!w)
return -ENOMEM;
w->func = fib6_node_dump;
arg.net = net;
arg.nb = nb;
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)
fib6_table_dump(net, tb, w);
}
kfree(w);
return 0;
}
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);
if (res >= 0) {
/* Frame is full, suspend walking */
w->leaf = rt;
return 1;
}
/* 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;
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;
} 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)
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;
}
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;
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) {
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.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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