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WSL2-Linux-Kernel/net/ipv4/fib_trie.c

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/*
* 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.
*
* Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
* & Swedish University of Agricultural Sciences.
*
* Jens Laas <jens.laas@data.slu.se> Swedish University of
* Agricultural Sciences.
*
* Hans Liss <hans.liss@its.uu.se> Uppsala Universitet
*
* This work is based on the LPC-trie which is originally described in:
*
* An experimental study of compression methods for dynamic tries
* Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
* http://www.csc.kth.se/~snilsson/software/dyntrie2/
*
*
* IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
* IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
*
*
* Code from fib_hash has been reused which includes the following header:
*
*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 FIB: lookup engine and maintenance routines.
*
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* 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.
*
* Substantial contributions to this work comes from:
*
* David S. Miller, <davem@davemloft.net>
* Stephen Hemminger <shemminger@osdl.org>
* Paul E. McKenney <paulmck@us.ibm.com>
* Patrick McHardy <kaber@trash.net>
*/
#define VERSION "0.409"
#include <asm/uaccess.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/rcupdate.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/vmalloc.h>
#include <linux/notifier.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#include <trace/events/fib.h>
#include "fib_lookup.h"
static BLOCKING_NOTIFIER_HEAD(fib_chain);
int register_fib_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&fib_chain, nb);
}
EXPORT_SYMBOL(register_fib_notifier);
int unregister_fib_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&fib_chain, nb);
}
EXPORT_SYMBOL(unregister_fib_notifier);
int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info)
{
info->net = net;
return blocking_notifier_call_chain(&fib_chain, event_type, info);
}
static int call_fib_entry_notifiers(struct net *net,
enum fib_event_type event_type, u32 dst,
int dst_len, struct fib_info *fi,
u8 tos, u8 type, u32 tb_id, u32 nlflags)
{
struct fib_entry_notifier_info info = {
.dst = dst,
.dst_len = dst_len,
.fi = fi,
.tos = tos,
.type = type,
.tb_id = tb_id,
.nlflags = nlflags,
};
return call_fib_notifiers(net, event_type, &info.info);
}
#define MAX_STAT_DEPTH 32
#define KEYLENGTH (8*sizeof(t_key))
#define KEY_MAX ((t_key)~0)
typedef unsigned int t_key;
#define IS_TRIE(n) ((n)->pos >= KEYLENGTH)
#define IS_TNODE(n) ((n)->bits)
#define IS_LEAF(n) (!(n)->bits)
struct key_vector {
t_key key;
unsigned char pos; /* 2log(KEYLENGTH) bits needed */
unsigned char bits; /* 2log(KEYLENGTH) bits needed */
unsigned char slen;
union {
/* This list pointer if valid if (pos | bits) == 0 (LEAF) */
struct hlist_head leaf;
/* This array is valid if (pos | bits) > 0 (TNODE) */
struct key_vector __rcu *tnode[0];
};
};
struct tnode {
struct rcu_head rcu;
t_key empty_children; /* KEYLENGTH bits needed */
t_key full_children; /* KEYLENGTH bits needed */
struct key_vector __rcu *parent;
struct key_vector kv[1];
#define tn_bits kv[0].bits
};
#define TNODE_SIZE(n) offsetof(struct tnode, kv[0].tnode[n])
#define LEAF_SIZE TNODE_SIZE(1)
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats {
unsigned int gets;
unsigned int backtrack;
unsigned int semantic_match_passed;
unsigned int semantic_match_miss;
unsigned int null_node_hit;
unsigned int resize_node_skipped;
};
#endif
struct trie_stat {
unsigned int totdepth;
unsigned int maxdepth;
unsigned int tnodes;
unsigned int leaves;
unsigned int nullpointers;
unsigned int prefixes;
unsigned int nodesizes[MAX_STAT_DEPTH];
};
struct trie {
struct key_vector kv[1];
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats __percpu *stats;
#endif
};
static struct key_vector *resize(struct trie *t, struct key_vector *tn);
static size_t tnode_free_size;
/*
* synchronize_rcu after call_rcu for that many pages; it should be especially
* useful before resizing the root node with PREEMPT_NONE configs; the value was
* obtained experimentally, aiming to avoid visible slowdown.
*/
static const int sync_pages = 128;
static struct kmem_cache *fn_alias_kmem __read_mostly;
static struct kmem_cache *trie_leaf_kmem __read_mostly;
static inline struct tnode *tn_info(struct key_vector *kv)
{
return container_of(kv, struct tnode, kv[0]);
}
/* caller must hold RTNL */
#define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
#define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
/* caller must hold RCU read lock or RTNL */
#define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
#define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
/* wrapper for rcu_assign_pointer */
static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
{
if (n)
rcu_assign_pointer(tn_info(n)->parent, tp);
}
#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
/* This provides us with the number of children in this node, in the case of a
* leaf this will return 0 meaning none of the children are accessible.
*/
static inline unsigned long child_length(const struct key_vector *tn)
{
return (1ul << tn->bits) & ~(1ul);
}
#define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
static inline unsigned long get_index(t_key key, struct key_vector *kv)
{
unsigned long index = key ^ kv->key;
if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
return 0;
return index >> kv->pos;
}
/* To understand this stuff, an understanding of keys and all their bits is
* necessary. Every node in the trie has a key associated with it, but not
* all of the bits in that key are significant.
*
* Consider a node 'n' and its parent 'tp'.
*
* If n is a leaf, every bit in its key is significant. Its presence is
* necessitated by path compression, since during a tree traversal (when
* searching for a leaf - unless we are doing an insertion) we will completely
* ignore all skipped bits we encounter. Thus we need to verify, at the end of
* a potentially successful search, that we have indeed been walking the
* correct key path.
*
* Note that we can never "miss" the correct key in the tree if present by
* following the wrong path. Path compression ensures that segments of the key
* that are the same for all keys with a given prefix are skipped, but the
* skipped part *is* identical for each node in the subtrie below the skipped
* bit! trie_insert() in this implementation takes care of that.
*
* if n is an internal node - a 'tnode' here, the various parts of its key
* have many different meanings.
*
* Example:
* _________________________________________________________________
* | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
* -----------------------------------------------------------------
* 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
*
* _________________________________________________________________
* | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
* -----------------------------------------------------------------
* 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
*
* tp->pos = 22
* tp->bits = 3
* n->pos = 13
* n->bits = 4
*
* First, let's just ignore the bits that come before the parent tp, that is
* the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
* point we do not use them for anything.
*
* The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
* index into the parent's child array. That is, they will be used to find
* 'n' among tp's children.
*
* The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
* for the node n.
*
* All the bits we have seen so far are significant to the node n. The rest
* of the bits are really not needed or indeed known in n->key.
*
* The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
* n's child array, and will of course be different for each child.
*
* The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
* at this point.
*/
static const int halve_threshold = 25;
static const int inflate_threshold = 50;
static const int halve_threshold_root = 15;
static const int inflate_threshold_root = 30;
static void __alias_free_mem(struct rcu_head *head)
{
struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
kmem_cache_free(fn_alias_kmem, fa);
}
static inline void alias_free_mem_rcu(struct fib_alias *fa)
{
call_rcu(&fa->rcu, __alias_free_mem);
}
#define TNODE_KMALLOC_MAX \
ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
#define TNODE_VMALLOC_MAX \
ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
static void __node_free_rcu(struct rcu_head *head)
{
struct tnode *n = container_of(head, struct tnode, rcu);
if (!n->tn_bits)
kmem_cache_free(trie_leaf_kmem, n);
else
kvfree(n);
}
#define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
static struct tnode *tnode_alloc(int bits)
{
size_t size;
/* verify bits is within bounds */
if (bits > TNODE_VMALLOC_MAX)
return NULL;
/* determine size and verify it is non-zero and didn't overflow */
size = TNODE_SIZE(1ul << bits);
if (size <= PAGE_SIZE)
return kzalloc(size, GFP_KERNEL);
else
return vzalloc(size);
}
static inline void empty_child_inc(struct key_vector *n)
{
++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
}
static inline void empty_child_dec(struct key_vector *n)
{
tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
}
static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
{
struct key_vector *l;
struct tnode *kv;
kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
if (!kv)
return NULL;
/* initialize key vector */
l = kv->kv;
l->key = key;
l->pos = 0;
l->bits = 0;
l->slen = fa->fa_slen;
/* link leaf to fib alias */
INIT_HLIST_HEAD(&l->leaf);
hlist_add_head(&fa->fa_list, &l->leaf);
return l;
}
static struct key_vector *tnode_new(t_key key, int pos, int bits)
{
unsigned int shift = pos + bits;
struct key_vector *tn;
struct tnode *tnode;
/* verify bits and pos their msb bits clear and values are valid */
BUG_ON(!bits || (shift > KEYLENGTH));
tnode = tnode_alloc(bits);
if (!tnode)
return NULL;
pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
sizeof(struct key_vector *) << bits);
if (bits == KEYLENGTH)
tnode->full_children = 1;
else
tnode->empty_children = 1ul << bits;
tn = tnode->kv;
tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
tn->pos = pos;
tn->bits = bits;
tn->slen = pos;
return tn;
}
/* Check whether a tnode 'n' is "full", i.e. it is an internal node
* and no bits are skipped. See discussion in dyntree paper p. 6
*/
static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
{
return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
}
/* Add a child at position i overwriting the old value.
* Update the value of full_children and empty_children.
*/
static void put_child(struct key_vector *tn, unsigned long i,
struct key_vector *n)
{
struct key_vector *chi = get_child(tn, i);
int isfull, wasfull;
BUG_ON(i >= child_length(tn));
/* update emptyChildren, overflow into fullChildren */
if (!n && chi)
empty_child_inc(tn);
if (n && !chi)
empty_child_dec(tn);
/* update fullChildren */
wasfull = tnode_full(tn, chi);
isfull = tnode_full(tn, n);
if (wasfull && !isfull)
tn_info(tn)->full_children--;
else if (!wasfull && isfull)
tn_info(tn)->full_children++;
if (n && (tn->slen < n->slen))
tn->slen = n->slen;
rcu_assign_pointer(tn->tnode[i], n);
}
static void update_children(struct key_vector *tn)
{
unsigned long i;
/* update all of the child parent pointers */
for (i = child_length(tn); i;) {
struct key_vector *inode = get_child(tn, --i);
if (!inode)
continue;
/* Either update the children of a tnode that
* already belongs to us or update the child
* to point to ourselves.
*/
if (node_parent(inode) == tn)
update_children(inode);
else
node_set_parent(inode, tn);
}
}
static inline void put_child_root(struct key_vector *tp, t_key key,
struct key_vector *n)
{
if (IS_TRIE(tp))
rcu_assign_pointer(tp->tnode[0], n);
else
put_child(tp, get_index(key, tp), n);
}
static inline void tnode_free_init(struct key_vector *tn)
{
tn_info(tn)->rcu.next = NULL;
}
static inline void tnode_free_append(struct key_vector *tn,
struct key_vector *n)
{
tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
tn_info(tn)->rcu.next = &tn_info(n)->rcu;
}
static void tnode_free(struct key_vector *tn)
{
struct callback_head *head = &tn_info(tn)->rcu;
while (head) {
head = head->next;
tnode_free_size += TNODE_SIZE(1ul << tn->bits);
node_free(tn);
tn = container_of(head, struct tnode, rcu)->kv;
}
if (tnode_free_size >= PAGE_SIZE * sync_pages) {
tnode_free_size = 0;
synchronize_rcu();
}
}
static struct key_vector *replace(struct trie *t,
struct key_vector *oldtnode,
struct key_vector *tn)
{
struct key_vector *tp = node_parent(oldtnode);
unsigned long i;
/* setup the parent pointer out of and back into this node */
NODE_INIT_PARENT(tn, tp);
put_child_root(tp, tn->key, tn);
/* update all of the child parent pointers */
update_children(tn);
/* all pointers should be clean so we are done */
tnode_free(oldtnode);
/* resize children now that oldtnode is freed */
for (i = child_length(tn); i;) {
struct key_vector *inode = get_child(tn, --i);
/* resize child node */
if (tnode_full(tn, inode))
tn = resize(t, inode);
}
return tp;
}
static struct key_vector *inflate(struct trie *t,
struct key_vector *oldtnode)
{
struct key_vector *tn;
unsigned long i;
t_key m;
pr_debug("In inflate\n");
tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
if (!tn)
goto notnode;
/* prepare oldtnode to be freed */
tnode_free_init(oldtnode);
/* Assemble all of the pointers in our cluster, in this case that
* represents all of the pointers out of our allocated nodes that
* point to existing tnodes and the links between our allocated
* nodes.
*/
for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
struct key_vector *inode = get_child(oldtnode, --i);
struct key_vector *node0, *node1;
unsigned long j, k;
/* An empty child */
if (!inode)
continue;
/* A leaf or an internal node with skipped bits */
if (!tnode_full(oldtnode, inode)) {
put_child(tn, get_index(inode->key, tn), inode);
continue;
}
/* drop the node in the old tnode free list */
tnode_free_append(oldtnode, inode);
/* An internal node with two children */
if (inode->bits == 1) {
put_child(tn, 2 * i + 1, get_child(inode, 1));
put_child(tn, 2 * i, get_child(inode, 0));
continue;
}
/* We will replace this node 'inode' with two new
* ones, 'node0' and 'node1', each with half of the
* original children. The two new nodes will have
* a position one bit further down the key and this
* means that the "significant" part of their keys
* (see the discussion near the top of this file)
* will differ by one bit, which will be "0" in
* node0's key and "1" in node1's key. Since we are
* moving the key position by one step, the bit that
* we are moving away from - the bit at position
* (tn->pos) - is the one that will differ between
* node0 and node1. So... we synthesize that bit in the
* two new keys.
*/
node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
if (!node1)
goto nomem;
node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
tnode_free_append(tn, node1);
if (!node0)
goto nomem;
tnode_free_append(tn, node0);
/* populate child pointers in new nodes */
for (k = child_length(inode), j = k / 2; j;) {
put_child(node1, --j, get_child(inode, --k));
put_child(node0, j, get_child(inode, j));
put_child(node1, --j, get_child(inode, --k));
put_child(node0, j, get_child(inode, j));
}
/* link new nodes to parent */
NODE_INIT_PARENT(node1, tn);
NODE_INIT_PARENT(node0, tn);
/* link parent to nodes */
put_child(tn, 2 * i + 1, node1);
put_child(tn, 2 * i, node0);
}
/* setup the parent pointers into and out of this node */
return replace(t, oldtnode, tn);
nomem:
/* all pointers should be clean so we are done */
tnode_free(tn);
notnode:
return NULL;
}
static struct key_vector *halve(struct trie *t,
struct key_vector *oldtnode)
{
struct key_vector *tn;
unsigned long i;
pr_debug("In halve\n");
tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
if (!tn)
goto notnode;
/* prepare oldtnode to be freed */
tnode_free_init(oldtnode);
/* Assemble all of the pointers in our cluster, in this case that
* represents all of the pointers out of our allocated nodes that
* point to existing tnodes and the links between our allocated
* nodes.
*/
for (i = child_length(oldtnode); i;) {
struct key_vector *node1 = get_child(oldtnode, --i);
struct key_vector *node0 = get_child(oldtnode, --i);
struct key_vector *inode;
/* At least one of the children is empty */
if (!node1 || !node0) {
put_child(tn, i / 2, node1 ? : node0);
continue;
}
/* Two nonempty children */
inode = tnode_new(node0->key, oldtnode->pos, 1);
if (!inode)
goto nomem;
tnode_free_append(tn, inode);
/* initialize pointers out of node */
put_child(inode, 1, node1);
put_child(inode, 0, node0);
NODE_INIT_PARENT(inode, tn);
/* link parent to node */
put_child(tn, i / 2, inode);
}
/* setup the parent pointers into and out of this node */
return replace(t, oldtnode, tn);
nomem:
/* all pointers should be clean so we are done */
tnode_free(tn);
notnode:
return NULL;
}
static struct key_vector *collapse(struct trie *t,
struct key_vector *oldtnode)
{
struct key_vector *n, *tp;
unsigned long i;
/* scan the tnode looking for that one child that might still exist */
for (n = NULL, i = child_length(oldtnode); !n && i;)
n = get_child(oldtnode, --i);
/* compress one level */
tp = node_parent(oldtnode);
put_child_root(tp, oldtnode->key, n);
node_set_parent(n, tp);
/* drop dead node */
node_free(oldtnode);
return tp;
}
static unsigned char update_suffix(struct key_vector *tn)
{
unsigned char slen = tn->pos;
unsigned long stride, i;
/* search though the list of children looking for nodes that might
* have a suffix greater than the one we currently have. This is
* why we start with a stride of 2 since a stride of 1 would
* represent the nodes with suffix length equal to tn->pos
*/
for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
struct key_vector *n = get_child(tn, i);
if (!n || (n->slen <= slen))
continue;
/* update stride and slen based on new value */
stride <<= (n->slen - slen);
slen = n->slen;
i &= ~(stride - 1);
/* if slen covers all but the last bit we can stop here
* there will be nothing longer than that since only node
* 0 and 1 << (bits - 1) could have that as their suffix
* length.
*/
if ((slen + 1) >= (tn->pos + tn->bits))
break;
}
tn->slen = slen;
return slen;
}
/* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
* the Helsinki University of Technology and Matti Tikkanen of Nokia
* Telecommunications, page 6:
* "A node is doubled if the ratio of non-empty children to all
* children in the *doubled* node is at least 'high'."
*
* 'high' in this instance is the variable 'inflate_threshold'. It
* is expressed as a percentage, so we multiply it with
* child_length() and instead of multiplying by 2 (since the
* child array will be doubled by inflate()) and multiplying
* the left-hand side by 100 (to handle the percentage thing) we
* multiply the left-hand side by 50.
*
* The left-hand side may look a bit weird: child_length(tn)
* - tn->empty_children is of course the number of non-null children
* in the current node. tn->full_children is the number of "full"
* children, that is non-null tnodes with a skip value of 0.
* All of those will be doubled in the resulting inflated tnode, so
* we just count them one extra time here.
*
* A clearer way to write this would be:
*
* to_be_doubled = tn->full_children;
* not_to_be_doubled = child_length(tn) - tn->empty_children -
* tn->full_children;
*
* new_child_length = child_length(tn) * 2;
*
* new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
* new_child_length;
* if (new_fill_factor >= inflate_threshold)
*
* ...and so on, tho it would mess up the while () loop.
*
* anyway,
* 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
* inflate_threshold
*
* avoid a division:
* 100 * (not_to_be_doubled + 2*to_be_doubled) >=
* inflate_threshold * new_child_length
*
* expand not_to_be_doubled and to_be_doubled, and shorten:
* 100 * (child_length(tn) - tn->empty_children +
* tn->full_children) >= inflate_threshold * new_child_length
*
* expand new_child_length:
* 100 * (child_length(tn) - tn->empty_children +
* tn->full_children) >=
* inflate_threshold * child_length(tn) * 2
*
* shorten again:
* 50 * (tn->full_children + child_length(tn) -
* tn->empty_children) >= inflate_threshold *
* child_length(tn)
*
*/
static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
{
unsigned long used = child_length(tn);
unsigned long threshold = used;
/* Keep root node larger */
threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
used -= tn_info(tn)->empty_children;
used += tn_info(tn)->full_children;
/* if bits == KEYLENGTH then pos = 0, and will fail below */
return (used > 1) && tn->pos && ((50 * used) >= threshold);
}
static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
{
unsigned long used = child_length(tn);
unsigned long threshold = used;
/* Keep root node larger */
threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
used -= tn_info(tn)->empty_children;
/* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
}
static inline bool should_collapse(struct key_vector *tn)
{
unsigned long used = child_length(tn);
used -= tn_info(tn)->empty_children;
/* account for bits == KEYLENGTH case */
if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
used -= KEY_MAX;
/* One child or none, time to drop us from the trie */
return used < 2;
}
#define MAX_WORK 10
static struct key_vector *resize(struct trie *t, struct key_vector *tn)
{
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats __percpu *stats = t->stats;
#endif
struct key_vector *tp = node_parent(tn);
unsigned long cindex = get_index(tn->key, tp);
int max_work = MAX_WORK;
pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
tn, inflate_threshold, halve_threshold);
/* track the tnode via the pointer from the parent instead of
* doing it ourselves. This way we can let RCU fully do its
* thing without us interfering
*/
BUG_ON(tn != get_child(tp, cindex));
/* Double as long as the resulting node has a number of
* nonempty nodes that are above the threshold.
*/
while (should_inflate(tp, tn) && max_work) {
tp = inflate(t, tn);
if (!tp) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->resize_node_skipped);
#endif
break;
}
max_work--;
tn = get_child(tp, cindex);
}
/* update parent in case inflate failed */
tp = node_parent(tn);
/* Return if at least one inflate is run */
if (max_work != MAX_WORK)
return tp;
/* Halve as long as the number of empty children in this
* node is above threshold.
*/
while (should_halve(tp, tn) && max_work) {
tp = halve(t, tn);
if (!tp) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->resize_node_skipped);
#endif
break;
}
max_work--;
tn = get_child(tp, cindex);
}
/* Only one child remains */
if (should_collapse(tn))
return collapse(t, tn);
/* update parent in case halve failed */
tp = node_parent(tn);
/* Return if at least one deflate was run */
if (max_work != MAX_WORK)
return tp;
/* push the suffix length to the parent node */
if (tn->slen > tn->pos) {
unsigned char slen = update_suffix(tn);
if (slen > tp->slen)
tp->slen = slen;
}
return tp;
}
static void leaf_pull_suffix(struct key_vector *tp, struct key_vector *l)
{
while ((tp->slen > tp->pos) && (tp->slen > l->slen)) {
if (update_suffix(tp) > l->slen)
break;
tp = node_parent(tp);
}
}
static void leaf_push_suffix(struct key_vector *tn, struct key_vector *l)
{
/* if this is a new leaf then tn will be NULL and we can sort
* out parent suffix lengths as a part of trie_rebalance
*/
while (tn->slen < l->slen) {
tn->slen = l->slen;
tn = node_parent(tn);
}
}
/* rcu_read_lock needs to be hold by caller from readside */
static struct key_vector *fib_find_node(struct trie *t,
struct key_vector **tp, u32 key)
{
struct key_vector *pn, *n = t->kv;
unsigned long index = 0;
do {
pn = n;
n = get_child_rcu(n, index);
if (!n)
break;
index = get_cindex(key, n);
/* This bit of code is a bit tricky but it combines multiple
* checks into a single check. The prefix consists of the
* prefix plus zeros for the bits in the cindex. The index
* is the difference between the key and this value. From
* this we can actually derive several pieces of data.
* if (index >= (1ul << bits))
* we have a mismatch in skip bits and failed
* else
* we know the value is cindex
*
* This check is safe even if bits == KEYLENGTH due to the
* fact that we can only allocate a node with 32 bits if a
* long is greater than 32 bits.
*/
if (index >= (1ul << n->bits)) {
n = NULL;
break;
}
/* keep searching until we find a perfect match leaf or NULL */
} while (IS_TNODE(n));
*tp = pn;
return n;
}
/* Return the first fib alias matching TOS with
* priority less than or equal to PRIO.
*/
static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
u8 tos, u32 prio, u32 tb_id)
{
struct fib_alias *fa;
if (!fah)
return NULL;
hlist_for_each_entry(fa, fah, fa_list) {
if (fa->fa_slen < slen)
continue;
if (fa->fa_slen != slen)
break;
if (fa->tb_id > tb_id)
continue;
if (fa->tb_id != tb_id)
break;
if (fa->fa_tos > tos)
continue;
if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
return fa;
}
return NULL;
}
static void trie_rebalance(struct trie *t, struct key_vector *tn)
{
while (!IS_TRIE(tn))
tn = resize(t, tn);
}
static int fib_insert_node(struct trie *t, struct key_vector *tp,
struct fib_alias *new, t_key key)
{
struct key_vector *n, *l;
l = leaf_new(key, new);
if (!l)
goto noleaf;
/* retrieve child from parent node */
n = get_child(tp, get_index(key, tp));
/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
*
* Add a new tnode here
* first tnode need some special handling
* leaves us in position for handling as case 3
*/
if (n) {
struct key_vector *tn;
tn = tnode_new(key, __fls(key ^ n->key), 1);
if (!tn)
goto notnode;
/* initialize routes out of node */
NODE_INIT_PARENT(tn, tp);
put_child(tn, get_index(key, tn) ^ 1, n);
/* start adding routes into the node */
put_child_root(tp, key, tn);
node_set_parent(n, tn);
/* parent now has a NULL spot where the leaf can go */
tp = tn;
}
/* Case 3: n is NULL, and will just insert a new leaf */
NODE_INIT_PARENT(l, tp);
put_child_root(tp, key, l);
trie_rebalance(t, tp);
return 0;
notnode:
node_free(l);
noleaf:
return -ENOMEM;
}
static int fib_insert_alias(struct trie *t, struct key_vector *tp,
struct key_vector *l, struct fib_alias *new,
struct fib_alias *fa, t_key key)
{
if (!l)
return fib_insert_node(t, tp, new, key);
if (fa) {
hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
} else {
struct fib_alias *last;
hlist_for_each_entry(last, &l->leaf, fa_list) {
if (new->fa_slen < last->fa_slen)
break;
if ((new->fa_slen == last->fa_slen) &&
(new->tb_id > last->tb_id))
break;
fa = last;
}
if (fa)
hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
else
hlist_add_head_rcu(&new->fa_list, &l->leaf);
}
/* if we added to the tail node then we need to update slen */
if (l->slen < new->fa_slen) {
l->slen = new->fa_slen;
leaf_push_suffix(tp, l);
}
return 0;
}
/* Caller must hold RTNL. */
int fib_table_insert(struct net *net, struct fib_table *tb,
struct fib_config *cfg)
{
struct trie *t = (struct trie *)tb->tb_data;
struct fib_alias *fa, *new_fa;
struct key_vector *l, *tp;
u16 nlflags = NLM_F_EXCL;
struct fib_info *fi;
u8 plen = cfg->fc_dst_len;
u8 slen = KEYLENGTH - plen;
u8 tos = cfg->fc_tos;
u32 key;
int err;
if (plen > KEYLENGTH)
return -EINVAL;
key = ntohl(cfg->fc_dst);
pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
if ((plen < KEYLENGTH) && (key << plen))
return -EINVAL;
fi = fib_create_info(cfg);
if (IS_ERR(fi)) {
err = PTR_ERR(fi);
goto err;
}
l = fib_find_node(t, &tp, key);
fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
tb->tb_id) : NULL;
/* Now fa, if non-NULL, points to the first fib alias
* with the same keys [prefix,tos,priority], if such key already
* exists or to the node before which we will insert new one.
*
* If fa is NULL, we will need to allocate a new one and
* insert to the tail of the section matching the suffix length
* of the new alias.
*/
if (fa && fa->fa_tos == tos &&
fa->fa_info->fib_priority == fi->fib_priority) {
struct fib_alias *fa_first, *fa_match;
err = -EEXIST;
if (cfg->fc_nlflags & NLM_F_EXCL)
goto out;
nlflags &= ~NLM_F_EXCL;
/* We have 2 goals:
* 1. Find exact match for type, scope, fib_info to avoid
* duplicate routes
* 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
*/
fa_match = NULL;
fa_first = fa;
hlist_for_each_entry_from(fa, fa_list) {
if ((fa->fa_slen != slen) ||
(fa->tb_id != tb->tb_id) ||
(fa->fa_tos != tos))
break;
if (fa->fa_info->fib_priority != fi->fib_priority)
break;
if (fa->fa_type == cfg->fc_type &&
fa->fa_info == fi) {
fa_match = fa;
break;
}
}
if (cfg->fc_nlflags & NLM_F_REPLACE) {
struct fib_info *fi_drop;
u8 state;
nlflags |= NLM_F_REPLACE;
fa = fa_first;
if (fa_match) {
if (fa == fa_match)
err = 0;
goto out;
}
err = -ENOBUFS;
new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
if (!new_fa)
goto out;
fi_drop = fa->fa_info;
new_fa->fa_tos = fa->fa_tos;
new_fa->fa_info = fi;
new_fa->fa_type = cfg->fc_type;
state = fa->fa_state;
new_fa->fa_state = state & ~FA_S_ACCESSED;
new_fa->fa_slen = fa->fa_slen;
new_fa->tb_id = tb->tb_id;
new_fa->fa_default = -1;
hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
alias_free_mem_rcu(fa);
fib_release_info(fi_drop);
if (state & FA_S_ACCESSED)
rt_cache_flush(cfg->fc_nlinfo.nl_net);
call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_ADD,
key, plen, fi,
new_fa->fa_tos, cfg->fc_type,
tb->tb_id, cfg->fc_nlflags);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
tb->tb_id, &cfg->fc_nlinfo, nlflags);
goto succeeded;
}
/* Error if we find a perfect match which
* uses the same scope, type, and nexthop
* information.
*/
if (fa_match)
goto out;
if (cfg->fc_nlflags & NLM_F_APPEND)
nlflags |= NLM_F_APPEND;
else
fa = fa_first;
}
err = -ENOENT;
if (!(cfg->fc_nlflags & NLM_F_CREATE))
goto out;
nlflags |= NLM_F_CREATE;
err = -ENOBUFS;
new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
if (!new_fa)
goto out;
new_fa->fa_info = fi;
new_fa->fa_tos = tos;
new_fa->fa_type = cfg->fc_type;
new_fa->fa_state = 0;
new_fa->fa_slen = slen;
new_fa->tb_id = tb->tb_id;
new_fa->fa_default = -1;
/* Insert new entry to the list. */
err = fib_insert_alias(t, tp, l, new_fa, fa, key);
if (err)
goto out_free_new_fa;
if (!plen)
tb->tb_num_default++;
rt_cache_flush(cfg->fc_nlinfo.nl_net);
call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_ADD, key, plen, fi, tos,
cfg->fc_type, tb->tb_id, cfg->fc_nlflags);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
&cfg->fc_nlinfo, nlflags);
succeeded:
return 0;
out_free_new_fa:
kmem_cache_free(fn_alias_kmem, new_fa);
out:
fib_release_info(fi);
err:
return err;
}
static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
{
t_key prefix = n->key;
return (key ^ prefix) & (prefix | -prefix);
}
/* should be called with rcu_read_lock */
int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
struct fib_result *res, int fib_flags)
{
struct trie *t = (struct trie *) tb->tb_data;
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats __percpu *stats = t->stats;
#endif
const t_key key = ntohl(flp->daddr);
struct key_vector *n, *pn;
struct fib_alias *fa;
unsigned long index;
t_key cindex;
trace_fib_table_lookup(tb->tb_id, flp);
pn = t->kv;
cindex = 0;
n = get_child_rcu(pn, cindex);
if (!n)
return -EAGAIN;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->gets);
#endif
/* Step 1: Travel to the longest prefix match in the trie */
for (;;) {
index = get_cindex(key, n);
/* This bit of code is a bit tricky but it combines multiple
* checks into a single check. The prefix consists of the
* prefix plus zeros for the "bits" in the prefix. The index
* is the difference between the key and this value. From
* this we can actually derive several pieces of data.
* if (index >= (1ul << bits))
* we have a mismatch in skip bits and failed
* else
* we know the value is cindex
*
* This check is safe even if bits == KEYLENGTH due to the
* fact that we can only allocate a node with 32 bits if a
* long is greater than 32 bits.
*/
if (index >= (1ul << n->bits))
break;
/* we have found a leaf. Prefixes have already been compared */
if (IS_LEAF(n))
goto found;
/* only record pn and cindex if we are going to be chopping
* bits later. Otherwise we are just wasting cycles.
*/
if (n->slen > n->pos) {
pn = n;
cindex = index;
}
n = get_child_rcu(n, index);
if (unlikely(!n))
goto backtrace;
}
/* Step 2: Sort out leaves and begin backtracing for longest prefix */
for (;;) {
/* record the pointer where our next node pointer is stored */
struct key_vector __rcu **cptr = n->tnode;
/* This test verifies that none of the bits that differ
* between the key and the prefix exist in the region of
* the lsb and higher in the prefix.
*/
if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
goto backtrace;
/* exit out and process leaf */
if (unlikely(IS_LEAF(n)))
break;
/* Don't bother recording parent info. Since we are in
* prefix match mode we will have to come back to wherever
* we started this traversal anyway
*/
while ((n = rcu_dereference(*cptr)) == NULL) {
backtrace:
#ifdef CONFIG_IP_FIB_TRIE_STATS
if (!n)
this_cpu_inc(stats->null_node_hit);
#endif
/* If we are at cindex 0 there are no more bits for
* us to strip at this level so we must ascend back
* up one level to see if there are any more bits to
* be stripped there.
*/
while (!cindex) {
t_key pkey = pn->key;
/* If we don't have a parent then there is
* nothing for us to do as we do not have any
* further nodes to parse.
*/
if (IS_TRIE(pn))
return -EAGAIN;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->backtrack);
#endif
/* Get Child's index */
pn = node_parent_rcu(pn);
cindex = get_index(pkey, pn);
}
/* strip the least significant bit from the cindex */
cindex &= cindex - 1;
/* grab pointer for next child node */
cptr = &pn->tnode[cindex];
}
}
found:
/* this line carries forward the xor from earlier in the function */
index = key ^ n->key;
/* Step 3: Process the leaf, if that fails fall back to backtracing */
hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
struct fib_info *fi = fa->fa_info;
int nhsel, err;
if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
if (index >= (1ul << fa->fa_slen))
continue;
}
if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
continue;
if (fi->fib_dead)
continue;
if (fa->fa_info->fib_scope < flp->flowi4_scope)
continue;
fib_alias_accessed(fa);
err = fib_props[fa->fa_type].error;
if (unlikely(err < 0)) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_passed);
#endif
return err;
}
if (fi->fib_flags & RTNH_F_DEAD)
continue;
for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
const struct fib_nh *nh = &fi->fib_nh[nhsel];
struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
if (nh->nh_flags & RTNH_F_DEAD)
continue;
if (in_dev &&
IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
nh->nh_flags & RTNH_F_LINKDOWN &&
!(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
continue;
if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
if (flp->flowi4_oif &&
flp->flowi4_oif != nh->nh_oif)
continue;
}
if (!(fib_flags & FIB_LOOKUP_NOREF))
atomic_inc(&fi->fib_clntref);
res->prefixlen = KEYLENGTH - fa->fa_slen;
res->nh_sel = nhsel;
res->type = fa->fa_type;
res->scope = fi->fib_scope;
res->fi = fi;
res->table = tb;
res->fa_head = &n->leaf;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_passed);
#endif
trace_fib_table_lookup_nh(nh);
return err;
}
}
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_miss);
#endif
goto backtrace;
}
EXPORT_SYMBOL_GPL(fib_table_lookup);
static void fib_remove_alias(struct trie *t, struct key_vector *tp,
struct key_vector *l, struct fib_alias *old)
{
/* record the location of the previous list_info entry */
struct hlist_node **pprev = old->fa_list.pprev;
struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
/* remove the fib_alias from the list */
hlist_del_rcu(&old->fa_list);
/* if we emptied the list this leaf will be freed and we can sort
* out parent suffix lengths as a part of trie_rebalance
*/
if (hlist_empty(&l->leaf)) {
put_child_root(tp, l->key, NULL);
node_free(l);
trie_rebalance(t, tp);
return;
}
/* only access fa if it is pointing at the last valid hlist_node */
if (*pprev)
return;
/* update the trie with the latest suffix length */
l->slen = fa->fa_slen;
leaf_pull_suffix(tp, l);
}
/* Caller must hold RTNL. */
int fib_table_delete(struct net *net, struct fib_table *tb,
struct fib_config *cfg)
{
struct trie *t = (struct trie *) tb->tb_data;
struct fib_alias *fa, *fa_to_delete;
struct key_vector *l, *tp;
u8 plen = cfg->fc_dst_len;
u8 slen = KEYLENGTH - plen;
u8 tos = cfg->fc_tos;
u32 key;
if (plen > KEYLENGTH)
return -EINVAL;
key = ntohl(cfg->fc_dst);
if ((plen < KEYLENGTH) && (key << plen))
return -EINVAL;
l = fib_find_node(t, &tp, key);
if (!l)
return -ESRCH;
fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
if (!fa)
return -ESRCH;
pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
fa_to_delete = NULL;
hlist_for_each_entry_from(fa, fa_list) {
struct fib_info *fi = fa->fa_info;
if ((fa->fa_slen != slen) ||
(fa->tb_id != tb->tb_id) ||
(fa->fa_tos != tos))
break;
if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
(cfg->fc_scope == RT_SCOPE_NOWHERE ||
fa->fa_info->fib_scope == cfg->fc_scope) &&
(!cfg->fc_prefsrc ||
fi->fib_prefsrc == cfg->fc_prefsrc) &&
(!cfg->fc_protocol ||
fi->fib_protocol == cfg->fc_protocol) &&
fib_nh_match(cfg, fi) == 0) {
fa_to_delete = fa;
break;
}
}
if (!fa_to_delete)
return -ESRCH;
call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
fa_to_delete->fa_info, tos, cfg->fc_type,
tb->tb_id, 0);
rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
&cfg->fc_nlinfo, 0);
if (!plen)
tb->tb_num_default--;
fib_remove_alias(t, tp, l, fa_to_delete);
if (fa_to_delete->fa_state & FA_S_ACCESSED)
rt_cache_flush(cfg->fc_nlinfo.nl_net);
fib_release_info(fa_to_delete->fa_info);
alias_free_mem_rcu(fa_to_delete);
return 0;
}
/* Scan for the next leaf starting at the provided key value */
static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
{
struct key_vector *pn, *n = *tn;
unsigned long cindex;
/* this loop is meant to try and find the key in the trie */
do {
/* record parent and next child index */
pn = n;
cindex = (key > pn->key) ? get_index(key, pn) : 0;
if (cindex >> pn->bits)
break;
/* descend into the next child */
n = get_child_rcu(pn, cindex++);
if (!n)
break;
/* guarantee forward progress on the keys */
if (IS_LEAF(n) && (n->key >= key))
goto found;
} while (IS_TNODE(n));
/* this loop will search for the next leaf with a greater key */
while (!IS_TRIE(pn)) {
/* if we exhausted the parent node we will need to climb */
if (cindex >= (1ul << pn->bits)) {
t_key pkey = pn->key;
pn = node_parent_rcu(pn);
cindex = get_index(pkey, pn) + 1;
continue;
}
/* grab the next available node */
n = get_child_rcu(pn, cindex++);
if (!n)
continue;
/* no need to compare keys since we bumped the index */
if (IS_LEAF(n))
goto found;
/* Rescan start scanning in new node */
pn = n;
cindex = 0;
}
*tn = pn;
return NULL; /* Root of trie */
found:
/* if we are at the limit for keys just return NULL for the tnode */
*tn = pn;
return n;
}
static void fib_trie_free(struct fib_table *tb)
{
struct trie *t = (struct trie *)tb->tb_data;
struct key_vector *pn = t->kv;
unsigned long cindex = 1;
struct hlist_node *tmp;
struct fib_alias *fa;
/* walk trie in reverse order and free everything */
for (;;) {
struct key_vector *n;
if (!(cindex--)) {
t_key pkey = pn->key;
if (IS_TRIE(pn))
break;
n = pn;
pn = node_parent(pn);
/* drop emptied tnode */
put_child_root(pn, n->key, NULL);
node_free(n);
cindex = get_index(pkey, pn);
continue;
}
/* grab the next available node */
n = get_child(pn, cindex);
if (!n)
continue;
if (IS_TNODE(n)) {
/* record pn and cindex for leaf walking */
pn = n;
cindex = 1ul << n->bits;
continue;
}
hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
hlist_del_rcu(&fa->fa_list);
alias_free_mem_rcu(fa);
}
put_child_root(pn, n->key, NULL);
node_free(n);
}
#ifdef CONFIG_IP_FIB_TRIE_STATS
free_percpu(t->stats);
#endif
kfree(tb);
}
struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
{
struct trie *ot = (struct trie *)oldtb->tb_data;
struct key_vector *l, *tp = ot->kv;
struct fib_table *local_tb;
struct fib_alias *fa;
struct trie *lt;
t_key key = 0;
if (oldtb->tb_data == oldtb->__data)
return oldtb;
local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
if (!local_tb)
return NULL;
lt = (struct trie *)local_tb->tb_data;
while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
struct key_vector *local_l = NULL, *local_tp;
hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
struct fib_alias *new_fa;
if (local_tb->tb_id != fa->tb_id)
continue;
/* clone fa for new local table */
new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
if (!new_fa)
goto out;
memcpy(new_fa, fa, sizeof(*fa));
/* insert clone into table */
if (!local_l)
local_l = fib_find_node(lt, &local_tp, l->key);
if (fib_insert_alias(lt, local_tp, local_l, new_fa,
NULL, l->key))
goto out;
}
/* stop loop if key wrapped back to 0 */
key = l->key + 1;
if (key < l->key)
break;
}
return local_tb;
out:
fib_trie_free(local_tb);
return NULL;
}
/* Caller must hold RTNL. */
int fib_table_flush(struct net *net, struct fib_table *tb)
{
struct trie *t = (struct trie *)tb->tb_data;
struct key_vector *pn = t->kv;
unsigned long cindex = 1;
struct hlist_node *tmp;
struct fib_alias *fa;
int found = 0;
/* walk trie in reverse order */
for (;;) {
unsigned char slen = 0;
struct key_vector *n;
if (!(cindex--)) {
t_key pkey = pn->key;
/* cannot resize the trie vector */
if (IS_TRIE(pn))
break;
/* resize completed node */
pn = resize(t, pn);
cindex = get_index(pkey, pn);
continue;
}
/* grab the next available node */
n = get_child(pn, cindex);
if (!n)
continue;
if (IS_TNODE(n)) {
/* record pn and cindex for leaf walking */
pn = n;
cindex = 1ul << n->bits;
continue;
}
hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
struct fib_info *fi = fa->fa_info;
if (!fi || !(fi->fib_flags & RTNH_F_DEAD)) {
slen = fa->fa_slen;
continue;
}
call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
n->key,
KEYLENGTH - fa->fa_slen,
fi, fa->fa_tos, fa->fa_type,
tb->tb_id, 0);
hlist_del_rcu(&fa->fa_list);
fib_release_info(fa->fa_info);
alias_free_mem_rcu(fa);
found++;
}
/* update leaf slen */
n->slen = slen;
if (hlist_empty(&n->leaf)) {
put_child_root(pn, n->key, NULL);
node_free(n);
}
}
pr_debug("trie_flush found=%d\n", found);
return found;
}
static void __trie_free_rcu(struct rcu_head *head)
{
struct fib_table *tb = container_of(head, struct fib_table, rcu);
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie *t = (struct trie *)tb->tb_data;
if (tb->tb_data == tb->__data)
free_percpu(t->stats);
#endif /* CONFIG_IP_FIB_TRIE_STATS */
kfree(tb);
}
void fib_free_table(struct fib_table *tb)
{
call_rcu(&tb->rcu, __trie_free_rcu);
}
static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
struct sk_buff *skb, struct netlink_callback *cb)
{
__be32 xkey = htonl(l->key);
struct fib_alias *fa;
int i, s_i;
s_i = cb->args[4];
i = 0;
/* rcu_read_lock is hold by caller */
hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
if (i < s_i) {
i++;
continue;
}
if (tb->tb_id != fa->tb_id) {
i++;
continue;
}
if (fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
RTM_NEWROUTE,
tb->tb_id,
fa->fa_type,
xkey,
KEYLENGTH - fa->fa_slen,
fa->fa_tos,
fa->fa_info, NLM_F_MULTI) < 0) {
cb->args[4] = i;
return -1;
}
i++;
}
cb->args[4] = i;
return skb->len;
}
/* rcu_read_lock needs to be hold by caller from readside */
int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct trie *t = (struct trie *)tb->tb_data;
struct key_vector *l, *tp = t->kv;
/* Dump starting at last key.
* Note: 0.0.0.0/0 (ie default) is first key.
*/
int count = cb->args[2];
t_key key = cb->args[3];
while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
cb->args[3] = key;
cb->args[2] = count;
return -1;
}
++count;
key = l->key + 1;
memset(&cb->args[4], 0,
sizeof(cb->args) - 4*sizeof(cb->args[0]));
/* stop loop if key wrapped back to 0 */
if (key < l->key)
break;
}
cb->args[3] = key;
cb->args[2] = count;
return skb->len;
}
void __init fib_trie_init(void)
{
fn_alias_kmem = kmem_cache_create("ip_fib_alias",
sizeof(struct fib_alias),
0, SLAB_PANIC, NULL);
trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
LEAF_SIZE,
0, SLAB_PANIC, NULL);
}
struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
{
struct fib_table *tb;
struct trie *t;
size_t sz = sizeof(*tb);
if (!alias)
sz += sizeof(struct trie);
tb = kzalloc(sz, GFP_KERNEL);
if (!tb)
return NULL;
tb->tb_id = id;
tb->tb_num_default = 0;
tb->tb_data = (alias ? alias->__data : tb->__data);
if (alias)
return tb;
t = (struct trie *) tb->tb_data;
t->kv[0].pos = KEYLENGTH;
t->kv[0].slen = KEYLENGTH;
#ifdef CONFIG_IP_FIB_TRIE_STATS
t->stats = alloc_percpu(struct trie_use_stats);
if (!t->stats) {
kfree(tb);
tb = NULL;
}
#endif
return tb;
}
#ifdef CONFIG_PROC_FS
/* Depth first Trie walk iterator */
struct fib_trie_iter {
struct seq_net_private p;
struct fib_table *tb;
struct key_vector *tnode;
unsigned int index;
unsigned int depth;
};
static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
{
unsigned long cindex = iter->index;
struct key_vector *pn = iter->tnode;
t_key pkey;
pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
iter->tnode, iter->index, iter->depth);
while (!IS_TRIE(pn)) {
while (cindex < child_length(pn)) {
struct key_vector *n = get_child_rcu(pn, cindex++);
if (!n)
continue;
if (IS_LEAF(n)) {
iter->tnode = pn;
iter->index = cindex;
} else {
/* push down one level */
iter->tnode = n;
iter->index = 0;
++iter->depth;
}
return n;
}
/* Current node exhausted, pop back up */
pkey = pn->key;
pn = node_parent_rcu(pn);
cindex = get_index(pkey, pn) + 1;
--iter->depth;
}
/* record root node so further searches know we are done */
iter->tnode = pn;
iter->index = 0;
return NULL;
}
static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
struct trie *t)
{
struct key_vector *n, *pn;
if (!t)
return NULL;
pn = t->kv;
n = rcu_dereference(pn->tnode[0]);
if (!n)
return NULL;
if (IS_TNODE(n)) {
iter->tnode = n;
iter->index = 0;
iter->depth = 1;
} else {
iter->tnode = pn;
iter->index = 0;
iter->depth = 0;
}
return n;
}
static void trie_collect_stats(struct trie *t, struct trie_stat *s)
{
struct key_vector *n;
struct fib_trie_iter iter;
memset(s, 0, sizeof(*s));
rcu_read_lock();
for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
if (IS_LEAF(n)) {
struct fib_alias *fa;
s->leaves++;
s->totdepth += iter.depth;
if (iter.depth > s->maxdepth)
s->maxdepth = iter.depth;
hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
++s->prefixes;
} else {
s->tnodes++;
if (n->bits < MAX_STAT_DEPTH)
s->nodesizes[n->bits]++;
s->nullpointers += tn_info(n)->empty_children;
}
}
rcu_read_unlock();
}
/*
* This outputs /proc/net/fib_triestats
*/
static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
{
unsigned int i, max, pointers, bytes, avdepth;
if (stat->leaves)
avdepth = stat->totdepth*100 / stat->leaves;
else
avdepth = 0;
seq_printf(seq, "\tAver depth: %u.%02d\n",
avdepth / 100, avdepth % 100);
seq_printf(seq, "\tMax depth: %u\n", stat->maxdepth);
seq_printf(seq, "\tLeaves: %u\n", stat->leaves);
bytes = LEAF_SIZE * stat->leaves;
seq_printf(seq, "\tPrefixes: %u\n", stat->prefixes);
bytes += sizeof(struct fib_alias) * stat->prefixes;
seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
bytes += TNODE_SIZE(0) * stat->tnodes;
max = MAX_STAT_DEPTH;
while (max > 0 && stat->nodesizes[max-1] == 0)
max--;
pointers = 0;
for (i = 1; i < max; i++)
if (stat->nodesizes[i] != 0) {
seq_printf(seq, " %u: %u", i, stat->nodesizes[i]);
pointers += (1<<i) * stat->nodesizes[i];
}
seq_putc(seq, '\n');
seq_printf(seq, "\tPointers: %u\n", pointers);
bytes += sizeof(struct key_vector *) * pointers;
seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
seq_printf(seq, "Total size: %u kB\n", (bytes + 1023) / 1024);
}
#ifdef CONFIG_IP_FIB_TRIE_STATS
static void trie_show_usage(struct seq_file *seq,
const struct trie_use_stats __percpu *stats)
{
struct trie_use_stats s = { 0 };
int cpu;
/* loop through all of the CPUs and gather up the stats */
for_each_possible_cpu(cpu) {
const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
s.gets += pcpu->gets;
s.backtrack += pcpu->backtrack;
s.semantic_match_passed += pcpu->semantic_match_passed;
s.semantic_match_miss += pcpu->semantic_match_miss;
s.null_node_hit += pcpu->null_node_hit;
s.resize_node_skipped += pcpu->resize_node_skipped;
}
seq_printf(seq, "\nCounters:\n---------\n");
seq_printf(seq, "gets = %u\n", s.gets);
seq_printf(seq, "backtracks = %u\n", s.backtrack);
seq_printf(seq, "semantic match passed = %u\n",
s.semantic_match_passed);
seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
}
#endif /* CONFIG_IP_FIB_TRIE_STATS */
static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
{
if (tb->tb_id == RT_TABLE_LOCAL)
seq_puts(seq, "Local:\n");
else if (tb->tb_id == RT_TABLE_MAIN)
seq_puts(seq, "Main:\n");
else
seq_printf(seq, "Id %d:\n", tb->tb_id);
}
static int fib_triestat_seq_show(struct seq_file *seq, void *v)
{
struct net *net = (struct net *)seq->private;
unsigned int h;
seq_printf(seq,
"Basic info: size of leaf:"
" %Zd bytes, size of tnode: %Zd bytes.\n",
LEAF_SIZE, TNODE_SIZE(0));
for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
struct hlist_head *head = &net->ipv4.fib_table_hash[h];
struct fib_table *tb;
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
struct trie *t = (struct trie *) tb->tb_data;
struct trie_stat stat;
if (!t)
continue;
fib_table_print(seq, tb);
trie_collect_stats(t, &stat);
trie_show_stats(seq, &stat);
#ifdef CONFIG_IP_FIB_TRIE_STATS
trie_show_usage(seq, t->stats);
#endif
}
}
return 0;
}
static int fib_triestat_seq_open(struct inode *inode, struct file *file)
{
return single_open_net(inode, file, fib_triestat_seq_show);
}
static const struct file_operations fib_triestat_fops = {
.owner = THIS_MODULE,
.open = fib_triestat_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release_net,
};
static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
{
struct fib_trie_iter *iter = seq->private;
struct net *net = seq_file_net(seq);
loff_t idx = 0;
unsigned int h;
for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
struct hlist_head *head = &net->ipv4.fib_table_hash[h];
struct fib_table *tb;
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
struct key_vector *n;
for (n = fib_trie_get_first(iter,
(struct trie *) tb->tb_data);
n; n = fib_trie_get_next(iter))
if (pos == idx++) {
iter->tb = tb;
return n;
}
}
}
return NULL;
}
static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
rcu_read_lock();
return fib_trie_get_idx(seq, *pos);
}
static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct fib_trie_iter *iter = seq->private;
struct net *net = seq_file_net(seq);
struct fib_table *tb = iter->tb;
struct hlist_node *tb_node;
unsigned int h;
struct key_vector *n;
++*pos;
/* next node in same table */
n = fib_trie_get_next(iter);
if (n)
return n;
/* walk rest of this hash chain */
h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
if (n)
goto found;
}
/* new hash chain */
while (++h < FIB_TABLE_HASHSZ) {
struct hlist_head *head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
if (n)
goto found;
}
}
return NULL;
found:
iter->tb = tb;
return n;
}
static void fib_trie_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
rcu_read_unlock();
}
static void seq_indent(struct seq_file *seq, int n)
{
while (n-- > 0)
seq_puts(seq, " ");
}
static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
{
switch (s) {
case RT_SCOPE_UNIVERSE: return "universe";
case RT_SCOPE_SITE: return "site";
case RT_SCOPE_LINK: return "link";
case RT_SCOPE_HOST: return "host";
case RT_SCOPE_NOWHERE: return "nowhere";
default:
snprintf(buf, len, "scope=%d", s);
return buf;
}
}
static const char *const rtn_type_names[__RTN_MAX] = {
[RTN_UNSPEC] = "UNSPEC",
[RTN_UNICAST] = "UNICAST",
[RTN_LOCAL] = "LOCAL",
[RTN_BROADCAST] = "BROADCAST",
[RTN_ANYCAST] = "ANYCAST",
[RTN_MULTICAST] = "MULTICAST",
[RTN_BLACKHOLE] = "BLACKHOLE",
[RTN_UNREACHABLE] = "UNREACHABLE",
[RTN_PROHIBIT] = "PROHIBIT",
[RTN_THROW] = "THROW",
[RTN_NAT] = "NAT",
[RTN_XRESOLVE] = "XRESOLVE",
};
static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
{
if (t < __RTN_MAX && rtn_type_names[t])
return rtn_type_names[t];
snprintf(buf, len, "type %u", t);
return buf;
}
/* Pretty print the trie */
static int fib_trie_seq_show(struct seq_file *seq, void *v)
{
const struct fib_trie_iter *iter = seq->private;
struct key_vector *n = v;
if (IS_TRIE(node_parent_rcu(n)))
fib_table_print(seq, iter->tb);
if (IS_TNODE(n)) {
__be32 prf = htonl(n->key);
seq_indent(seq, iter->depth-1);
seq_printf(seq, " +-- %pI4/%zu %u %u %u\n",
&prf, KEYLENGTH - n->pos - n->bits, n->bits,
tn_info(n)->full_children,
tn_info(n)->empty_children);
} else {
__be32 val = htonl(n->key);
struct fib_alias *fa;
seq_indent(seq, iter->depth);
seq_printf(seq, " |-- %pI4\n", &val);
hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
char buf1[32], buf2[32];
seq_indent(seq, iter->depth + 1);
seq_printf(seq, " /%zu %s %s",
KEYLENGTH - fa->fa_slen,
rtn_scope(buf1, sizeof(buf1),
fa->fa_info->fib_scope),
rtn_type(buf2, sizeof(buf2),
fa->fa_type));
if (fa->fa_tos)
seq_printf(seq, " tos=%d", fa->fa_tos);
seq_putc(seq, '\n');
}
}
return 0;
}
static const struct seq_operations fib_trie_seq_ops = {
.start = fib_trie_seq_start,
.next = fib_trie_seq_next,
.stop = fib_trie_seq_stop,
.show = fib_trie_seq_show,
};
static int fib_trie_seq_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &fib_trie_seq_ops,
sizeof(struct fib_trie_iter));
}
static const struct file_operations fib_trie_fops = {
.owner = THIS_MODULE,
.open = fib_trie_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
struct fib_route_iter {
struct seq_net_private p;
struct fib_table *main_tb;
struct key_vector *tnode;
loff_t pos;
t_key key;
};
static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
loff_t pos)
{
struct key_vector *l, **tp = &iter->tnode;
t_key key;
/* use cache location of next-to-find key */
if (iter->pos > 0 && pos >= iter->pos) {
pos -= iter->pos;
key = iter->key;
} else {
iter->pos = 0;
key = 0;
}
while ((l = leaf_walk_rcu(tp, key)) != NULL) {
key = l->key + 1;
iter->pos++;
if (--pos <= 0)
break;
l = NULL;
/* handle unlikely case of a key wrap */
if (!key)
break;
}
if (l)
iter->key = key; /* remember it */
else
iter->pos = 0; /* forget it */
return l;
}
static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
struct fib_route_iter *iter = seq->private;
struct fib_table *tb;
struct trie *t;
rcu_read_lock();
tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
if (!tb)
return NULL;
iter->main_tb = tb;
t = (struct trie *)tb->tb_data;
iter->tnode = t->kv;
if (*pos != 0)
return fib_route_get_idx(iter, *pos);
iter->pos = 0;
iter->key = 0;
return SEQ_START_TOKEN;
}
static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct fib_route_iter *iter = seq->private;
struct key_vector *l = NULL;
t_key key = iter->key;
++*pos;
/* only allow key of 0 for start of sequence */
if ((v == SEQ_START_TOKEN) || key)
l = leaf_walk_rcu(&iter->tnode, key);
if (l) {
iter->key = l->key + 1;
iter->pos++;
} else {
iter->pos = 0;
}
return l;
}
static void fib_route_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
rcu_read_unlock();
}
static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
{
unsigned int flags = 0;
if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
flags = RTF_REJECT;
if (fi && fi->fib_nh->nh_gw)
flags |= RTF_GATEWAY;
if (mask == htonl(0xFFFFFFFF))
flags |= RTF_HOST;
flags |= RTF_UP;
return flags;
}
/*
* This outputs /proc/net/route.
* The format of the file is not supposed to be changed
* and needs to be same as fib_hash output to avoid breaking
* legacy utilities
*/
static int fib_route_seq_show(struct seq_file *seq, void *v)
{
struct fib_route_iter *iter = seq->private;
struct fib_table *tb = iter->main_tb;
struct fib_alias *fa;
struct key_vector *l = v;
__be32 prefix;
if (v == SEQ_START_TOKEN) {
seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
"\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
"\tWindow\tIRTT");
return 0;
}
prefix = htonl(l->key);
hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
const struct fib_info *fi = fa->fa_info;
__be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
if ((fa->fa_type == RTN_BROADCAST) ||
(fa->fa_type == RTN_MULTICAST))
continue;
if (fa->tb_id != tb->tb_id)
continue;
seq_setwidth(seq, 127);
if (fi)
seq_printf(seq,
"%s\t%08X\t%08X\t%04X\t%d\t%u\t"
"%d\t%08X\t%d\t%u\t%u",
fi->fib_dev ? fi->fib_dev->name : "*",
prefix,
fi->fib_nh->nh_gw, flags, 0, 0,
fi->fib_priority,
mask,
(fi->fib_advmss ?
fi->fib_advmss + 40 : 0),
fi->fib_window,
fi->fib_rtt >> 3);
else
seq_printf(seq,
"*\t%08X\t%08X\t%04X\t%d\t%u\t"
"%d\t%08X\t%d\t%u\t%u",
prefix, 0, flags, 0, 0, 0,
mask, 0, 0, 0);
seq_pad(seq, '\n');
}
return 0;
}
static const struct seq_operations fib_route_seq_ops = {
.start = fib_route_seq_start,
.next = fib_route_seq_next,
.stop = fib_route_seq_stop,
.show = fib_route_seq_show,
};
static int fib_route_seq_open(struct inode *inode, struct file *file)
{
return seq_open_net(inode, file, &fib_route_seq_ops,
sizeof(struct fib_route_iter));
}
static const struct file_operations fib_route_fops = {
.owner = THIS_MODULE,
.open = fib_route_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_net,
};
int __net_init fib_proc_init(struct net *net)
{
if (!proc_create("fib_trie", S_IRUGO, net->proc_net, &fib_trie_fops))
goto out1;
if (!proc_create("fib_triestat", S_IRUGO, net->proc_net,
&fib_triestat_fops))
goto out2;
if (!proc_create("route", S_IRUGO, net->proc_net, &fib_route_fops))
goto out3;
return 0;
out3:
remove_proc_entry("fib_triestat", net->proc_net);
out2:
remove_proc_entry("fib_trie", net->proc_net);
out1:
return -ENOMEM;
}
void __net_exit fib_proc_exit(struct net *net)
{
remove_proc_entry("fib_trie", net->proc_net);
remove_proc_entry("fib_triestat", net->proc_net);
remove_proc_entry("route", net->proc_net);
}
#endif /* CONFIG_PROC_FS */
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