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WSL2-Linux-Kernel/net/ipv6/ip6_fib.c

1604 строки
33 KiB
C
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/*
* Linux INET6 implementation
* Forwarding Information Database
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/*
* 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.
*/
#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/ipv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#define RT6_DEBUG 2
#if RT6_DEBUG >= 3
#define RT6_TRACE(x...) printk(KERN_DEBUG x)
#else
#define RT6_TRACE(x...) do { ; } while (0)
#endif
static struct kmem_cache * fib6_node_kmem __read_mostly;
enum fib_walk_state_t
{
#ifdef CONFIG_IPV6_SUBTREES
FWS_S,
#endif
FWS_L,
FWS_R,
FWS_C,
FWS_U
};
struct fib6_cleaner_t
{
struct fib6_walker_t w;
struct net *net;
int (*func)(struct rt6_info *, void *arg);
void *arg;
};
static DEFINE_RWLOCK(fib6_walker_lock);
#ifdef CONFIG_IPV6_SUBTREES
#define FWS_INIT FWS_S
#else
#define FWS_INIT FWS_L
#endif
static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
struct rt6_info *rt);
static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
static struct fib6_node *fib6_repair_tree(struct net *net, struct fib6_node *fn);
static int fib6_walk(struct fib6_walker_t *w);
static int fib6_walk_continue(struct fib6_walker_t *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 __u32 rt_sernum;
static void fib6_gc_timer_cb(unsigned long arg);
static LIST_HEAD(fib6_walkers);
#define FOR_WALKERS(w) list_for_each_entry(w, &fib6_walkers, lh)
static inline void fib6_walker_link(struct fib6_walker_t *w)
{
write_lock_bh(&fib6_walker_lock);
list_add(&w->lh, &fib6_walkers);
write_unlock_bh(&fib6_walker_lock);
}
static inline void fib6_walker_unlink(struct fib6_walker_t *w)
{
write_lock_bh(&fib6_walker_lock);
list_del(&w->lh);
write_unlock_bh(&fib6_walker_lock);
}
static __inline__ u32 fib6_new_sernum(void)
{
u32 n = ++rt_sernum;
if ((__s32)n <= 0)
rt_sernum = n = 1;
return n;
}
/*
* 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 __inline__ __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];
}
static __inline__ struct fib6_node * node_alloc(void)
{
struct fib6_node *fn;
fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
return fn;
}
static __inline__ void node_free(struct fib6_node * fn)
{
kmem_cache_free(fib6_node_kmem, fn);
}
static __inline__ void rt6_release(struct rt6_info *rt)
{
if (atomic_dec_and_test(&rt->rt6i_ref))
dst_free(&rt->dst);
}
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.
*/
rwlock_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 != NULL) {
table->tb6_id = id;
table->tb6_root.leaf = net->ipv6.ip6_null_entry;
table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
}
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 != NULL)
fib6_link_table(net, tb);
return tb;
}
struct fib6_table *fib6_get_table(struct net *net, u32 id)
{
struct fib6_table *tb;
struct hlist_head *head;
struct hlist_node *node;
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, node, head, tb6_hlist) {
if (tb->tb6_id == id) {
rcu_read_unlock();
return tb;
}
}
rcu_read_unlock();
return NULL;
}
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,
int flags, pol_lookup_t lookup)
{
return (struct dst_entry *) lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
}
static void __net_init fib6_tables_init(struct net *net)
{
fib6_link_table(net, net->ipv6.fib6_main_tbl);
}
#endif
static int fib6_dump_node(struct fib6_walker_t *w)
{
int res;
struct rt6_info *rt;
for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
res = rt6_dump_route(rt, w->args);
if (res < 0) {
/* Frame is full, suspend walking */
w->leaf = rt;
return 1;
}
WARN_ON(res == 0);
}
w->leaf = NULL;
return 0;
}
static void fib6_dump_end(struct netlink_callback *cb)
{
struct fib6_walker_t *w = (void*)cb->args[2];
if (w) {
if (cb->args[4]) {
cb->args[4] = 0;
fib6_walker_unlink(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 fib6_walker_t *w;
int res;
w = (void *)cb->args[2];
w->root = &table->tb6_root;
if (cb->args[4] == 0) {
w->count = 0;
w->skip = 0;
read_lock_bh(&table->tb6_lock);
res = fib6_walk(w);
read_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;
read_lock_bh(&table->tb6_lock);
res = fib6_walk_continue(w);
read_unlock_bh(&table->tb6_lock);
if (res <= 0) {
fib6_walker_unlink(w);
cb->args[4] = 0;
}
}
return res;
}
static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
unsigned int h, s_h;
unsigned int e = 0, s_e;
struct rt6_rtnl_dump_arg arg;
struct fib6_walker_t *w;
struct fib6_table *tb;
struct hlist_node *node;
struct hlist_head *head;
int res = 0;
s_h = cb->args[0];
s_e = cb->args[1];
w = (void *)cb->args[2];
if (w == NULL) {
/* 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 == NULL)
return -ENOMEM;
w->func = fib6_dump_node;
cb->args[2] = (long)w;
}
arg.skb = skb;
arg.cb = cb;
arg.net = net;
w->args = &arg;
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, node, head, tb6_hlist) {
if (e < s_e)
goto next;
res = fib6_dump_table(tb, skb, cb);
if (res != 0)
goto out;
next:
e++;
}
}
out:
rcu_read_unlock();
cb->args[1] = e;
cb->args[0] = h;
res = res < 0 ? res : skb->len;
if (res <= 0)
fib6_dump_end(cb);
return res;
}
/*
* 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 fib6_node *root, void *addr,
int addrlen, int plen,
int offset)
{
struct fib6_node *fn, *in, *ln;
struct fib6_node *pn = NULL;
struct rt6key *key;
int bit;
__be32 dir = 0;
__u32 sernum = fib6_new_sernum();
RT6_TRACE("fib6_add_1\n");
/* insert node in tree */
fn = root;
do {
key = (struct rt6key *)((u8 *)fn->leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
goto insert_above;
/*
* Exact match ?
*/
if (plen == fn->fn_bit) {
/* clean up an intermediate node */
if ((fn->fn_flags & RTN_RTINFO) == 0) {
rt6_release(fn->leaf);
fn->leaf = NULL;
}
fn->fn_sernum = sernum;
return fn;
}
/*
* We have more bits to go
*/
/* Try to walk down on tree. */
fn->fn_sernum = sernum;
dir = addr_bit_set(addr, fn->fn_bit);
pn = fn;
fn = dir ? fn->right: fn->left;
} while (fn);
/*
* We walked to the bottom of tree.
* Create new leaf node without children.
*/
ln = node_alloc();
if (ln == NULL)
return NULL;
ln->fn_bit = plen;
ln->parent = pn;
ln->fn_sernum = sernum;
if (dir)
pn->right = ln;
else
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 = fn->parent;
/* 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, addrlen);
/*
* (intermediate)[in]
* / \
* (new leaf node)[ln] (old node)[fn]
*/
if (plen > bit) {
in = node_alloc();
ln = node_alloc();
if (in == NULL || ln == NULL) {
if (in)
node_free(in);
if (ln)
node_free(ln);
return NULL;
}
/*
* 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;
in->parent = pn;
in->leaf = fn->leaf;
atomic_inc(&in->leaf->rt6i_ref);
in->fn_sernum = sernum;
/* update parent pointer */
if (dir)
pn->right = in;
else
pn->left = in;
ln->fn_bit = plen;
ln->parent = in;
fn->parent = in;
ln->fn_sernum = sernum;
if (addr_bit_set(addr, bit)) {
in->right = ln;
in->left = fn;
} else {
in->left = ln;
in->right = fn;
}
} else { /* plen <= bit */
/*
* (new leaf node)[ln]
* / \
* (old node)[fn] NULL
*/
ln = node_alloc();
if (ln == NULL)
return NULL;
ln->fn_bit = plen;
ln->parent = pn;
ln->fn_sernum = sernum;
if (dir)
pn->right = ln;
else
pn->left = ln;
if (addr_bit_set(&key->addr, plen))
ln->right = fn;
else
ln->left = fn;
fn->parent = ln;
}
return ln;
}
/*
* Insert routing information in a node.
*/
static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
struct nl_info *info)
{
struct rt6_info *iter = NULL;
struct rt6_info **ins;
ins = &fn->leaf;
for (iter = fn->leaf; iter; iter=iter->dst.rt6_next) {
/*
* Search for duplicates
*/
if (iter->rt6i_metric == rt->rt6i_metric) {
/*
* Same priority level
*/
if (iter->rt6i_dev == rt->rt6i_dev &&
iter->rt6i_idev == rt->rt6i_idev &&
ipv6_addr_equal(&iter->rt6i_gateway,
&rt->rt6i_gateway)) {
if (!(iter->rt6i_flags&RTF_EXPIRES))
return -EEXIST;
iter->rt6i_expires = rt->rt6i_expires;
if (!(rt->rt6i_flags&RTF_EXPIRES)) {
iter->rt6i_flags &= ~RTF_EXPIRES;
iter->rt6i_expires = 0;
}
return -EEXIST;
}
}
if (iter->rt6i_metric > rt->rt6i_metric)
break;
ins = &iter->dst.rt6_next;
}
/* Reset round-robin state, if necessary */
if (ins == &fn->leaf)
fn->rr_ptr = NULL;
/*
* insert node
*/
rt->dst.rt6_next = iter;
*ins = rt;
rt->rt6i_node = fn;
atomic_inc(&rt->rt6i_ref);
inet6_rt_notify(RTM_NEWROUTE, rt, info);
info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
if ((fn->fn_flags & RTN_RTINFO) == 0) {
info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
fn->fn_flags |= RTN_RTINFO;
}
return 0;
}
static __inline__ void fib6_start_gc(struct net *net, struct rt6_info *rt)
{
if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
(rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
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);
}
/*
* Add routing information to the routing tree.
* <destination addr>/<source addr>
* with source addr info in sub-trees
*/
int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
{
struct fib6_node *fn, *pn = NULL;
int err = -ENOMEM;
fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
if (fn == NULL)
goto out;
pn = fn;
#ifdef CONFIG_IPV6_SUBTREES
if (rt->rt6i_src.plen) {
struct fib6_node *sn;
if (fn->subtree == NULL) {
struct fib6_node *sfn;
/*
* Create subtree.
*
* fn[main tree]
* |
* sfn[subtree root]
* \
* sn[new leaf node]
*/
/* Create subtree root node */
sfn = node_alloc();
if (sfn == NULL)
goto st_failure;
sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
sfn->fn_flags = RTN_ROOT;
sfn->fn_sernum = fib6_new_sernum();
/* Now add the first leaf node to new subtree */
sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
sizeof(struct in6_addr), rt->rt6i_src.plen,
offsetof(struct rt6_info, rt6i_src));
if (sn == NULL) {
/* If it is failed, discard just allocated
root, and then (in st_failure) stale node
in main tree.
*/
node_free(sfn);
goto st_failure;
}
/* Now link new subtree to main tree */
sfn->parent = fn;
fn->subtree = sfn;
} else {
sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
sizeof(struct in6_addr), rt->rt6i_src.plen,
offsetof(struct rt6_info, rt6i_src));
if (sn == NULL)
goto st_failure;
}
if (fn->leaf == NULL) {
fn->leaf = rt;
atomic_inc(&rt->rt6i_ref);
}
fn = sn;
}
#endif
err = fib6_add_rt2node(fn, rt, info);
if (err == 0) {
fib6_start_gc(info->nl_net, rt);
if (!(rt->rt6i_flags&RTF_CACHE))
fib6_prune_clones(info->nl_net, pn, 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 && pn->leaf == rt) {
pn->leaf = NULL;
atomic_dec(&rt->rt6i_ref);
}
if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
pn->leaf = fib6_find_prefix(info->nl_net, pn);
#if RT6_DEBUG >= 2
if (!pn->leaf) {
WARN_ON(pn->leaf == NULL);
pn->leaf = info->nl_net->ipv6.ip6_null_entry;
}
#endif
atomic_inc(&pn->leaf->rt6i_ref);
}
#endif
dst_free(&rt->dst);
}
return err;
#ifdef CONFIG_IPV6_SUBTREES
/* Subtree creation failed, probably main tree node
is orphan. If it is, shoot it.
*/
st_failure:
if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
fib6_repair_tree(info->nl_net, fn);
dst_free(&rt->dst);
return err;
#endif
}
/*
* Routing tree lookup
*
*/
struct lookup_args {
int offset; /* key offset on rt6_info */
const struct in6_addr *addr; /* search key */
};
static struct fib6_node * fib6_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 ? fn->right : fn->left;
if (next) {
fn = next;
continue;
}
break;
}
while(fn) {
if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
struct rt6key *key;
key = (struct rt6key *) ((u8 *) fn->leaf +
args->offset);
if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
#ifdef CONFIG_IPV6_SUBTREES
if (fn->subtree)
fn = fib6_lookup_1(fn->subtree, args + 1);
#endif
if (!fn || fn->fn_flags & RTN_RTINFO)
return fn;
}
}
if (fn->fn_flags & RTN_ROOT)
break;
fn = fn->parent;
}
return NULL;
}
struct fib6_node * fib6_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 rt6_info, rt6i_dst),
.addr = daddr,
},
#ifdef CONFIG_IPV6_SUBTREES
{
.offset = offsetof(struct rt6_info, rt6i_src),
.addr = saddr,
},
#endif
{
.offset = 0, /* sentinel */
}
};
fn = fib6_lookup_1(root, daddr ? args : args + 1);
if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
fn = root;
return fn;
}
/*
* Get node with specified destination prefix (and source prefix,
* if subtrees are used)
*/
static struct fib6_node * fib6_locate_1(struct fib6_node *root,
const struct in6_addr *addr,
int plen, int offset)
{
struct fib6_node *fn;
for (fn = root; fn ; ) {
struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
return NULL;
if (plen == fn->fn_bit)
return fn;
/*
* We have more bits to go
*/
if (addr_bit_set(addr, fn->fn_bit))
fn = fn->right;
else
fn = fn->left;
}
return NULL;
}
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)
{
struct fib6_node *fn;
fn = fib6_locate_1(root, daddr, dst_len,
offsetof(struct rt6_info, rt6i_dst));
#ifdef CONFIG_IPV6_SUBTREES
if (src_len) {
WARN_ON(saddr == NULL);
if (fn && fn->subtree)
fn = fib6_locate_1(fn->subtree, saddr, src_len,
offsetof(struct rt6_info, rt6i_src));
}
#endif
if (fn && fn->fn_flags&RTN_RTINFO)
return fn;
return NULL;
}
/*
* Deletion
*
*/
static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
{
if (fn->fn_flags&RTN_ROOT)
return net->ipv6.ip6_null_entry;
while(fn) {
if(fn->left)
return fn->left->leaf;
if(fn->right)
return fn->right->leaf;
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.
*/
static struct fib6_node *fib6_repair_tree(struct net *net,
struct fib6_node *fn)
{
int children;
int nstate;
struct fib6_node *child, *pn;
struct fib6_walker_t *w;
int iter = 0;
for (;;) {
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 != NULL);
children = 0;
child = NULL;
if (fn->right) child = fn->right, children |= 1;
if (fn->left) child = fn->left, 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
) {
fn->leaf = fib6_find_prefix(net, fn);
#if RT6_DEBUG >= 2
if (fn->leaf==NULL) {
WARN_ON(!fn->leaf);
fn->leaf = net->ipv6.ip6_null_entry;
}
#endif
atomic_inc(&fn->leaf->rt6i_ref);
return fn->parent;
}
pn = fn->parent;
#ifdef CONFIG_IPV6_SUBTREES
if (FIB6_SUBTREE(pn) == fn) {
WARN_ON(!(fn->fn_flags & RTN_ROOT));
FIB6_SUBTREE(pn) = NULL;
nstate = FWS_L;
} else {
WARN_ON(fn->fn_flags & RTN_ROOT);
#endif
if (pn->right == fn) pn->right = child;
else if (pn->left == fn) pn->left = child;
#if RT6_DEBUG >= 2
else
WARN_ON(1);
#endif
if (child)
child->parent = pn;
nstate = FWS_R;
#ifdef CONFIG_IPV6_SUBTREES
}
#endif
read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
if (child == NULL) {
if (w->root == fn) {
w->root = w->node = NULL;
RT6_TRACE("W %p adjusted by delroot 1\n", w);
} else 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->root == fn) {
w->root = child;
RT6_TRACE("W %p adjusted by delroot 2\n", w);
}
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(&fib6_walker_lock);
node_free(fn);
if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn))
return pn;
rt6_release(pn->leaf);
pn->leaf = NULL;
fn = pn;
}
}
static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
struct nl_info *info)
{
struct fib6_walker_t *w;
struct rt6_info *rt = *rtp;
struct net *net = info->nl_net;
RT6_TRACE("fib6_del_route\n");
/* Unlink it */
*rtp = rt->dst.rt6_next;
rt->rt6i_node = NULL;
net->ipv6.rt6_stats->fib_rt_entries--;
net->ipv6.rt6_stats->fib_discarded_routes++;
/* Reset round-robin state, if necessary */
if (fn->rr_ptr == rt)
fn->rr_ptr = NULL;
/* Adjust walkers */
read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
if (w->state == FWS_C && w->leaf == rt) {
RT6_TRACE("walker %p adjusted by delroute\n", w);
w->leaf = rt->dst.rt6_next;
if (w->leaf == NULL)
w->state = FWS_U;
}
}
read_unlock(&fib6_walker_lock);
rt->dst.rt6_next = NULL;
/* If it was last route, expunge its radix tree node */
if (fn->leaf == NULL) {
fn->fn_flags &= ~RTN_RTINFO;
net->ipv6.rt6_stats->fib_route_nodes--;
fn = fib6_repair_tree(net, fn);
}
if (atomic_read(&rt->rt6i_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) {
if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
fn->leaf = fib6_find_prefix(net, fn);
atomic_inc(&fn->leaf->rt6i_ref);
rt6_release(rt);
}
fn = fn->parent;
}
/* No more references are possible at this point. */
BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
}
inet6_rt_notify(RTM_DELROUTE, rt, info);
rt6_release(rt);
}
int fib6_del(struct rt6_info *rt, struct nl_info *info)
{
struct net *net = info->nl_net;
struct fib6_node *fn = rt->rt6i_node;
struct rt6_info **rtp;
#if RT6_DEBUG >= 2
if (rt->dst.obsolete>0) {
WARN_ON(fn != NULL);
return -ENOENT;
}
#endif
if (fn == NULL || rt == net->ipv6.ip6_null_entry)
return -ENOENT;
WARN_ON(!(fn->fn_flags & RTN_RTINFO));
if (!(rt->rt6i_flags&RTF_CACHE)) {
struct fib6_node *pn = fn;
#ifdef CONFIG_IPV6_SUBTREES
/* clones of this route might be in another subtree */
if (rt->rt6i_src.plen) {
while (!(pn->fn_flags&RTN_ROOT))
pn = pn->parent;
pn = pn->parent;
}
#endif
fib6_prune_clones(info->nl_net, pn, rt);
}
/*
* Walk the leaf entries looking for ourself
*/
for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
if (*rtp == rt) {
fib6_del_route(fn, rtp, info);
return 0;
}
}
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.
*/
static int fib6_walk_continue(struct fib6_walker_t *w)
{
struct fib6_node *fn, *pn;
for (;;) {
fn = w->node;
if (fn == NULL)
return 0;
if (w->prune && fn != w->root &&
fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
w->state = FWS_C;
w->leaf = fn->leaf;
}
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
case FWS_L:
if (fn->left) {
w->node = fn->left;
w->state = FWS_INIT;
continue;
}
w->state = FWS_R;
case FWS_R:
if (fn->right) {
w->node = fn->right;
w->state = FWS_INIT;
continue;
}
w->state = FWS_C;
w->leaf = fn->leaf;
case FWS_C:
if (w->leaf && fn->fn_flags&RTN_RTINFO) {
int err;
if (w->count < w->skip) {
w->count++;
continue;
}
err = w->func(w);
if (err)
return err;
w->count++;
continue;
}
w->state = FWS_U;
case FWS_U:
if (fn == w->root)
return 0;
pn = fn->parent;
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 (pn->left == fn) {
w->state = FWS_R;
continue;
}
if (pn->right == fn) {
w->state = FWS_C;
w->leaf = w->node->leaf;
continue;
}
#if RT6_DEBUG >= 2
WARN_ON(1);
#endif
}
}
}
static int fib6_walk(struct fib6_walker_t *w)
{
int res;
w->state = FWS_INIT;
w->node = w->root;
fib6_walker_link(w);
res = fib6_walk_continue(w);
if (res <= 0)
fib6_walker_unlink(w);
return res;
}
static int fib6_clean_node(struct fib6_walker_t *w)
{
int res;
struct rt6_info *rt;
struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
struct nl_info info = {
.nl_net = c->net,
};
for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
res = c->func(rt, c->arg);
if (res < 0) {
w->leaf = rt;
res = fib6_del(rt, &info);
if (res) {
#if RT6_DEBUG >= 2
printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
#endif
continue;
}
return 0;
}
WARN_ON(res != 0);
}
w->leaf = rt;
return 0;
}
/*
* Convenient frontend to tree walker.
*
* func is called on each route.
* It may return -1 -> delete this route.
* 0 -> continue walking
*
* prune==1 -> only immediate children of node (certainly,
* ignoring pure split nodes) will be scanned.
*/
static void fib6_clean_tree(struct net *net, struct fib6_node *root,
int (*func)(struct rt6_info *, void *arg),
int prune, void *arg)
{
struct fib6_cleaner_t c;
c.w.root = root;
c.w.func = fib6_clean_node;
c.w.prune = prune;
c.w.count = 0;
c.w.skip = 0;
c.func = func;
c.arg = arg;
c.net = net;
fib6_walk(&c.w);
}
void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
int prune, void *arg)
{
struct fib6_table *table;
struct hlist_node *node;
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, node, head, tb6_hlist) {
write_lock_bh(&table->tb6_lock);
fib6_clean_tree(net, &table->tb6_root,
func, prune, arg);
write_unlock_bh(&table->tb6_lock);
}
}
rcu_read_unlock();
}
static int fib6_prune_clone(struct rt6_info *rt, void *arg)
{
if (rt->rt6i_flags & RTF_CACHE) {
RT6_TRACE("pruning clone %p\n", rt);
return -1;
}
return 0;
}
static void fib6_prune_clones(struct net *net, struct fib6_node *fn,
struct rt6_info *rt)
{
fib6_clean_tree(net, fn, fib6_prune_clone, 1, rt);
}
/*
* Garbage collection
*/
static struct fib6_gc_args
{
int timeout;
int more;
} gc_args;
static int fib6_age(struct rt6_info *rt, void *arg)
{
unsigned long now = jiffies;
/*
* check addrconf expiration here.
* Routes are expired even if they are in use.
*
* Also age clones. Note, that clones are aged out
* only if they are not in use now.
*/
if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
if (time_after(now, rt->rt6i_expires)) {
RT6_TRACE("expiring %p\n", rt);
return -1;
}
gc_args.more++;
} else if (rt->rt6i_flags & RTF_CACHE) {
if (atomic_read(&rt->dst.__refcnt) == 0 &&
time_after_eq(now, rt->dst.lastuse + gc_args.timeout)) {
RT6_TRACE("aging clone %p\n", rt);
return -1;
} else if ((rt->rt6i_flags & RTF_GATEWAY) &&
(!(dst_get_neighbour_raw(&rt->dst)->flags & NTF_ROUTER))) {
RT6_TRACE("purging route %p via non-router but gateway\n",
rt);
return -1;
}
gc_args.more++;
}
return 0;
}
static DEFINE_SPINLOCK(fib6_gc_lock);
void fib6_run_gc(unsigned long expires, struct net *net)
{
if (expires != ~0UL) {
spin_lock_bh(&fib6_gc_lock);
gc_args.timeout = expires ? (int)expires :
net->ipv6.sysctl.ip6_rt_gc_interval;
} else {
if (!spin_trylock_bh(&fib6_gc_lock)) {
mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
return;
}
gc_args.timeout = net->ipv6.sysctl.ip6_rt_gc_interval;
}
gc_args.more = icmp6_dst_gc();
fib6_clean_all(net, fib6_age, 0, NULL);
if (gc_args.more)
mod_timer(&net->ipv6.ip6_fib_timer,
round_jiffies(jiffies
+ net->ipv6.sysctl.ip6_rt_gc_interval));
else
del_timer(&net->ipv6.ip6_fib_timer);
spin_unlock_bh(&fib6_gc_lock);
}
static void fib6_gc_timer_cb(unsigned long arg)
{
fib6_run_gc(0, (struct net *)arg);
}
static int __net_init fib6_net_init(struct net *net)
{
size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
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;
net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
#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;
net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_null_entry;
net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
#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:
return -ENOMEM;
}
static void fib6_net_exit(struct net *net)
{
rt6_ifdown(net, NULL);
del_timer_sync(&net->ipv6.ip6_fib_timer);
#ifdef CONFIG_IPV6_MULTIPLE_TABLES
kfree(net->ipv6.fib6_local_tbl);
#endif
kfree(net->ipv6.fib6_main_tbl);
kfree(net->ipv6.fib_table_hash);
kfree(net->ipv6.rt6_stats);
}
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(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib,
NULL);
if (ret)
goto out_unregister_subsys;
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);
}
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