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linux/net/ipv4/fib_trie.c
Alexander Duyck 64c6272351 fib_trie: Various clean-ups for handling slen 
While doing further work on the fib_trie I noted a few items.

First I was using calls that were far more complicated than they needed to
be for determining when to push/pull the suffix length.  I have updated the
code to reflect the simplier logic.

The second issue is that I realised we weren't necessarily handling the
case of a leaf_info struct surviving a flush.  I have updated the logic so
that now we will call pull_suffix in the event of having a leaf info value
left in the leaf after flushing it.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-25 14:47:16 -08:00

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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 <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 "fib_lookup.h"
#define MAX_STAT_DEPTH 32
#define KEYLENGTH (8*sizeof(t_key))
#define KEY_MAX ((t_key)~0)
typedef unsigned int t_key;
#define IS_TNODE(n) ((n)->bits)
#define IS_LEAF(n) (!(n)->bits)
#define get_index(_key, _kv) (((_key) ^ (_kv)->key) >> (_kv)->pos)
struct tnode {
t_key key;
unsigned char bits; /* 2log(KEYLENGTH) bits needed */
unsigned char pos; /* 2log(KEYLENGTH) bits needed */
unsigned char slen;
struct tnode __rcu *parent;
struct rcu_head rcu;
union {
/* The fields in this struct are valid if bits > 0 (TNODE) */
struct {
t_key empty_children; /* KEYLENGTH bits needed */
t_key full_children; /* KEYLENGTH bits needed */
struct tnode __rcu *child[0];
};
/* This list pointer if valid if bits == 0 (LEAF) */
struct hlist_head list;
};
};
struct leaf_info {
struct hlist_node hlist;
int plen;
u32 mask_plen; /* ntohl(inet_make_mask(plen)) */
struct list_head falh;
struct rcu_head rcu;
};
#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 tnode __rcu *trie;
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats __percpu *stats;
#endif
};
static void resize(struct trie *t, struct tnode *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;
/* caller must hold RTNL */
#define node_parent(n) rtnl_dereference((n)->parent)
/* caller must hold RCU read lock or RTNL */
#define node_parent_rcu(n) rcu_dereference_rtnl((n)->parent)
/* wrapper for rcu_assign_pointer */
static inline void node_set_parent(struct tnode *n, struct tnode *tp)
{
if (n)
rcu_assign_pointer(n->parent, tp);
}
#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER((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 tnode_child_length(const struct tnode *tn)
{
return (1ul << tn->bits) & ~(1ul);
}
/* caller must hold RTNL */
static inline struct tnode *tnode_get_child(const struct tnode *tn,
unsigned long i)
{
return rtnl_dereference(tn->child[i]);
}
/* caller must hold RCU read lock or RTNL */
static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn,
unsigned long i)
{
return rcu_dereference_rtnl(tn->child[i]);
}
/* 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 (tn->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 + n->bits), 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 - sizeof(struct tnode)) / sizeof(struct tnode *))
static void __node_free_rcu(struct rcu_head *head)
{
struct tnode *n = container_of(head, struct tnode, rcu);
if (IS_LEAF(n))
kmem_cache_free(trie_leaf_kmem, n);
else if (n->bits <= TNODE_KMALLOC_MAX)
kfree(n);
else
vfree(n);
}
#define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
static inline void free_leaf_info(struct leaf_info *leaf)
{
kfree_rcu(leaf, rcu);
}
static struct tnode *tnode_alloc(size_t size)
{
if (size <= PAGE_SIZE)
return kzalloc(size, GFP_KERNEL);
else
return vzalloc(size);
}
static inline void empty_child_inc(struct tnode *n)
{
++n->empty_children ? : ++n->full_children;
}
static inline void empty_child_dec(struct tnode *n)
{
n->empty_children-- ? : n->full_children--;
}
static struct tnode *leaf_new(t_key key)
{
struct tnode *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
if (l) {
l->parent = NULL;
/* set key and pos to reflect full key value
* any trailing zeros in the key should be ignored
* as the nodes are searched
*/
l->key = key;
l->slen = 0;
l->pos = 0;
/* set bits to 0 indicating we are not a tnode */
l->bits = 0;
INIT_HLIST_HEAD(&l->list);
}
return l;
}
static struct leaf_info *leaf_info_new(int plen)
{
struct leaf_info *li = kmalloc(sizeof(struct leaf_info), GFP_KERNEL);
if (li) {
li->plen = plen;
li->mask_plen = ntohl(inet_make_mask(plen));
INIT_LIST_HEAD(&li->falh);
}
return li;
}
static struct tnode *tnode_new(t_key key, int pos, int bits)
{
size_t sz = offsetof(struct tnode, child[1ul << bits]);
struct tnode *tn = tnode_alloc(sz);
unsigned int shift = pos + bits;
/* verify bits and pos their msb bits clear and values are valid */
BUG_ON(!bits || (shift > KEYLENGTH));
if (tn) {
tn->parent = NULL;
tn->slen = pos;
tn->pos = pos;
tn->bits = bits;
tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
if (bits == KEYLENGTH)
tn->full_children = 1;
else
tn->empty_children = 1ul << bits;
}
pr_debug("AT %p s=%zu %zu\n", tn, sizeof(struct tnode),
sizeof(struct tnode *) << bits);
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(const struct tnode *tn, const struct tnode *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 tnode *tn, unsigned long i, struct tnode *n)
{
struct tnode *chi = tnode_get_child(tn, i);
int isfull, wasfull;
BUG_ON(i >= tnode_child_length(tn));
/* update emptyChildren, overflow into fullChildren */
if (n == NULL && chi != NULL)
empty_child_inc(tn);
if (n != NULL && chi == NULL)
empty_child_dec(tn);
/* update fullChildren */
wasfull = tnode_full(tn, chi);
isfull = tnode_full(tn, n);
if (wasfull && !isfull)
tn->full_children--;
else if (!wasfull && isfull)
tn->full_children++;
if (n && (tn->slen < n->slen))
tn->slen = n->slen;
rcu_assign_pointer(tn->child[i], n);
}
static void update_children(struct tnode *tn)
{
unsigned long i;
/* update all of the child parent pointers */
for (i = tnode_child_length(tn); i;) {
struct tnode *inode = tnode_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 tnode *tp, struct trie *t,
t_key key, struct tnode *n)
{
if (tp)
put_child(tp, get_index(key, tp), n);
else
rcu_assign_pointer(t->trie, n);
}
static inline void tnode_free_init(struct tnode *tn)
{
tn->rcu.next = NULL;
}
static inline void tnode_free_append(struct tnode *tn, struct tnode *n)
{
n->rcu.next = tn->rcu.next;
tn->rcu.next = &n->rcu;
}
static void tnode_free(struct tnode *tn)
{
struct callback_head *head = &tn->rcu;
while (head) {
head = head->next;
tnode_free_size += offsetof(struct tnode, child[1 << tn->bits]);
node_free(tn);
tn = container_of(head, struct tnode, rcu);
}
if (tnode_free_size >= PAGE_SIZE * sync_pages) {
tnode_free_size = 0;
synchronize_rcu();
}
}
static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
{
struct tnode *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, t, 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 = tnode_child_length(tn); i;) {
struct tnode *inode = tnode_get_child(tn, --i);
/* resize child node */
if (tnode_full(tn, inode))
resize(t, inode);
}
}
static int inflate(struct trie *t, struct tnode *oldtnode)
{
struct tnode *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)
return -ENOMEM;
/* 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 = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
struct tnode *inode = tnode_get_child(oldtnode, --i);
struct tnode *node0, *node1;
unsigned long j, k;
/* An empty child */
if (inode == NULL)
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, tnode_get_child(inode, 1));
put_child(tn, 2 * i, tnode_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 = tnode_child_length(inode), j = k / 2; j;) {
put_child(node1, --j, tnode_get_child(inode, --k));
put_child(node0, j, tnode_get_child(inode, j));
put_child(node1, --j, tnode_get_child(inode, --k));
put_child(node0, j, tnode_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 */
replace(t, oldtnode, tn);
return 0;
nomem:
/* all pointers should be clean so we are done */
tnode_free(tn);
return -ENOMEM;
}
static int halve(struct trie *t, struct tnode *oldtnode)
{
struct tnode *tn;
unsigned long i;
pr_debug("In halve\n");
tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
if (!tn)
return -ENOMEM;
/* 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 = tnode_child_length(oldtnode); i;) {
struct tnode *node1 = tnode_get_child(oldtnode, --i);
struct tnode *node0 = tnode_get_child(oldtnode, --i);
struct tnode *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) {
tnode_free(tn);
return -ENOMEM;
}
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 */
replace(t, oldtnode, tn);
return 0;
}
static void collapse(struct trie *t, struct tnode *oldtnode)
{
struct tnode *n, *tp;
unsigned long i;
/* scan the tnode looking for that one child that might still exist */
for (n = NULL, i = tnode_child_length(oldtnode); !n && i;)
n = tnode_get_child(oldtnode, --i);
/* compress one level */
tp = node_parent(oldtnode);
put_child_root(tp, t, oldtnode->key, n);
node_set_parent(n, tp);
/* drop dead node */
node_free(oldtnode);
}
static unsigned char update_suffix(struct tnode *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 < tnode_child_length(tn); i += stride) {
struct tnode *n = tnode_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
* tnode_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: tnode_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 = tnode_child_length(tn) - tn->empty_children -
* tn->full_children;
*
* new_child_length = tnode_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 * (tnode_child_length(tn) - tn->empty_children +
* tn->full_children) >= inflate_threshold * new_child_length
*
* expand new_child_length:
* 100 * (tnode_child_length(tn) - tn->empty_children +
* tn->full_children) >=
* inflate_threshold * tnode_child_length(tn) * 2
*
* shorten again:
* 50 * (tn->full_children + tnode_child_length(tn) -
* tn->empty_children) >= inflate_threshold *
* tnode_child_length(tn)
*
*/
static bool should_inflate(const struct tnode *tp, const struct tnode *tn)
{
unsigned long used = tnode_child_length(tn);
unsigned long threshold = used;
/* Keep root node larger */
threshold *= tp ? inflate_threshold : inflate_threshold_root;
used -= tn->empty_children;
used += tn->full_children;
/* if bits == KEYLENGTH then pos = 0, and will fail below */
return (used > 1) && tn->pos && ((50 * used) >= threshold);
}
static bool should_halve(const struct tnode *tp, const struct tnode *tn)
{
unsigned long used = tnode_child_length(tn);
unsigned long threshold = used;
/* Keep root node larger */
threshold *= tp ? halve_threshold : halve_threshold_root;
used -= 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 bool should_collapse(const struct tnode *tn)
{
unsigned long used = tnode_child_length(tn);
used -= tn->empty_children;
/* account for bits == KEYLENGTH case */
if ((tn->bits == KEYLENGTH) && 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 void resize(struct trie *t, struct tnode *tn)
{
struct tnode *tp = node_parent(tn);
struct tnode __rcu **cptr;
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
*/
cptr = tp ? &tp->child[get_index(tn->key, tp)] : &t->trie;
BUG_ON(tn != rtnl_dereference(*cptr));
/* 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) {
if (inflate(t, tn)) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(t->stats->resize_node_skipped);
#endif
break;
}
max_work--;
tn = rtnl_dereference(*cptr);
}
/* Return if at least one inflate is run */
if (max_work != MAX_WORK)
return;
/* Halve as long as the number of empty children in this
* node is above threshold.
*/
while (should_halve(tp, tn) && max_work) {
if (halve(t, tn)) {
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(t->stats->resize_node_skipped);
#endif
break;
}
max_work--;
tn = rtnl_dereference(*cptr);
}
/* Only one child remains */
if (should_collapse(tn)) {
collapse(t, tn);
return;
}
/* Return if at least one deflate was run */
if (max_work != MAX_WORK)
return;
/* push the suffix length to the parent node */
if (tn->slen > tn->pos) {
unsigned char slen = update_suffix(tn);
if (tp && (slen > tp->slen))
tp->slen = slen;
}
}
/* readside must use rcu_read_lock currently dump routines
via get_fa_head and dump */
static struct leaf_info *find_leaf_info(struct tnode *l, int plen)
{
struct hlist_head *head = &l->list;
struct leaf_info *li;
hlist_for_each_entry_rcu(li, head, hlist)
if (li->plen == plen)
return li;
return NULL;
}
static inline struct list_head *get_fa_head(struct tnode *l, int plen)
{
struct leaf_info *li = find_leaf_info(l, plen);
if (!li)
return NULL;
return &li->falh;
}
static void leaf_pull_suffix(struct tnode *l)
{
struct tnode *tp = node_parent(l);
while (tp && (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 tnode *l)
{
struct tnode *tn = node_parent(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 && (tn->slen < l->slen)) {
tn->slen = l->slen;
tn = node_parent(tn);
}
}
static void remove_leaf_info(struct tnode *l, struct leaf_info *old)
{
/* record the location of the previous list_info entry */
struct hlist_node **pprev = old->hlist.pprev;
struct leaf_info *li = hlist_entry(pprev, typeof(*li), hlist.next);
/* remove the leaf info from the list */
hlist_del_rcu(&old->hlist);
/* only access li if it is pointing at the last valid hlist_node */
if (hlist_empty(&l->list) || (*pprev))
return;
/* update the trie with the latest suffix length */
l->slen = KEYLENGTH - li->plen;
leaf_pull_suffix(l);
}
static void insert_leaf_info(struct tnode *l, struct leaf_info *new)
{
struct hlist_head *head = &l->list;
struct leaf_info *li = NULL, *last = NULL;
if (hlist_empty(head)) {
hlist_add_head_rcu(&new->hlist, head);
} else {
hlist_for_each_entry(li, head, hlist) {
if (new->plen > li->plen)
break;
last = li;
}
if (last)
hlist_add_behind_rcu(&new->hlist, &last->hlist);
else
hlist_add_before_rcu(&new->hlist, &li->hlist);
}
/* if we added to the tail node then we need to update slen */
if (l->slen < (KEYLENGTH - new->plen)) {
l->slen = KEYLENGTH - new->plen;
leaf_push_suffix(l);
}
}
/* rcu_read_lock needs to be hold by caller from readside */
static struct tnode *fib_find_node(struct trie *t, u32 key)
{
struct tnode *n = rcu_dereference_rtnl(t->trie);
while (n) {
unsigned long index = get_index(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 & (~0ul << bits))
* we have a mismatch in skip bits and failed
* else
* we know the value is cindex
*/
if (index & (~0ul << n->bits))
return NULL;
/* we have found a leaf. Prefixes have already been compared */
if (IS_LEAF(n))
break;
n = tnode_get_child_rcu(n, index);
}
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 list_head *fah, u8 tos, u32 prio)
{
struct fib_alias *fa;
if (!fah)
return NULL;
list_for_each_entry(fa, fah, fa_list) {
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 tnode *tn)
{
struct tnode *tp;
while ((tp = node_parent(tn)) != NULL) {
resize(t, tn);
tn = tp;
}
/* Handle last (top) tnode */
if (IS_TNODE(tn))
resize(t, tn);
}
/* only used from updater-side */
static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen)
{
struct list_head *fa_head = NULL;
struct tnode *l, *n, *tp = NULL;
struct leaf_info *li;
li = leaf_info_new(plen);
if (!li)
return NULL;
fa_head = &li->falh;
n = rtnl_dereference(t->trie);
/* If we point to NULL, stop. Either the tree is empty and we should
* just put a new leaf in if, or we have reached an empty child slot,
* and we should just put our new leaf in that.
*
* If we hit a node with a key that does't match then we should stop
* and create a new tnode to replace that node and insert ourselves
* and the other node into the new tnode.
*/
while (n) {
unsigned long index = get_index(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 >> bits)
* we know the value is child index
* else
* we have a mismatch in skip bits and failed
*/
if (index >> n->bits)
break;
/* we have found a leaf. Prefixes have already been compared */
if (IS_LEAF(n)) {
/* Case 1: n is a leaf, and prefixes match*/
insert_leaf_info(n, li);
return fa_head;
}
tp = n;
n = tnode_get_child_rcu(n, index);
}
l = leaf_new(key);
if (!l) {
free_leaf_info(li);
return NULL;
}
insert_leaf_info(l, li);
/* 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 tnode *tn;
tn = tnode_new(key, __fls(key ^ n->key), 1);
if (!tn) {
free_leaf_info(li);
node_free(l);
return NULL;
}
/* 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, t, 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 */
if (tp) {
NODE_INIT_PARENT(l, tp);
put_child(tp, get_index(key, tp), l);
trie_rebalance(t, tp);
} else {
rcu_assign_pointer(t->trie, l);
}
return fa_head;
}
/*
* Caller must hold RTNL.
*/
int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
{
struct trie *t = (struct trie *) tb->tb_data;
struct fib_alias *fa, *new_fa;
struct list_head *fa_head = NULL;
struct fib_info *fi;
int plen = cfg->fc_dst_len;
u8 tos = cfg->fc_tos;
u32 key, mask;
int err;
struct tnode *l;
if (plen > 32)
return -EINVAL;
key = ntohl(cfg->fc_dst);
pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
mask = ntohl(inet_make_mask(plen));
if (key & ~mask)
return -EINVAL;
key = key & mask;
fi = fib_create_info(cfg);
if (IS_ERR(fi)) {
err = PTR_ERR(fi);
goto err;
}
l = fib_find_node(t, key);
fa = NULL;
if (l) {
fa_head = get_fa_head(l, plen);
fa = fib_find_alias(fa_head, tos, fi->fib_priority);
}
/* 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 head of f.
*
* If f is NULL, no fib node matched the destination key
* and we need to allocate a new one of those as well.
*/
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;
/* 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;
fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
list_for_each_entry_continue(fa, fa_head, fa_list) {
if (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;
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 == NULL)
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;
list_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);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);
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))
fa = fa_first;
}
err = -ENOENT;
if (!(cfg->fc_nlflags & NLM_F_CREATE))
goto out;
err = -ENOBUFS;
new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
if (new_fa == NULL)
goto out;
new_fa->fa_info = fi;
new_fa->fa_tos = tos;
new_fa->fa_type = cfg->fc_type;
new_fa->fa_state = 0;
/*
* Insert new entry to the list.
*/
if (!fa_head) {
fa_head = fib_insert_node(t, key, plen);
if (unlikely(!fa_head)) {
err = -ENOMEM;
goto out_free_new_fa;
}
}
if (!plen)
tb->tb_num_default++;
list_add_tail_rcu(&new_fa->fa_list,
(fa ? &fa->fa_list : fa_head));
rt_cache_flush(cfg->fc_nlinfo.nl_net);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, tb->tb_id,
&cfg->fc_nlinfo, 0);
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 tnode *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 tnode *n, *pn;
struct leaf_info *li;
t_key cindex;
n = rcu_dereference(t->trie);
if (!n)
return -EAGAIN;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->gets);
#endif
pn = n;
cindex = 0;
/* Step 1: Travel to the longest prefix match in the trie */
for (;;) {
unsigned long index = get_index(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 & (~0ul << bits))
* we have a mismatch in skip bits and failed
* else
* we know the value is cindex
*/
if (index & (~0ul << 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 = tnode_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 tnode __rcu **cptr = n->child;
/* 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;
pn = node_parent_rcu(pn);
if (unlikely(!pn))
return -EAGAIN;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->backtrack);
#endif
/* Get Child's index */
cindex = get_index(pkey, pn);
}
/* strip the least significant bit from the cindex */
cindex &= cindex - 1;
/* grab pointer for next child node */
cptr = &pn->child[cindex];
}
}
found:
/* Step 3: Process the leaf, if that fails fall back to backtracing */
hlist_for_each_entry_rcu(li, &n->list, hlist) {
struct fib_alias *fa;
if ((key ^ n->key) & li->mask_plen)
continue;
list_for_each_entry_rcu(fa, &li->falh, fa_list) {
struct fib_info *fi = fa->fa_info;
int nhsel, err;
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];
if (nh->nh_flags & RTNH_F_DEAD)
continue;
if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
continue;
if (!(fib_flags & FIB_LOOKUP_NOREF))
atomic_inc(&fi->fib_clntref);
res->prefixlen = li->plen;
res->nh_sel = nhsel;
res->type = fa->fa_type;
res->scope = fi->fib_scope;
res->fi = fi;
res->table = tb;
res->fa_head = &li->falh;
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_passed);
#endif
return err;
}
}
#ifdef CONFIG_IP_FIB_TRIE_STATS
this_cpu_inc(stats->semantic_match_miss);
#endif
}
goto backtrace;
}
EXPORT_SYMBOL_GPL(fib_table_lookup);
/*
* Remove the leaf and return parent.
*/
static void trie_leaf_remove(struct trie *t, struct tnode *l)
{
struct tnode *tp = node_parent(l);
pr_debug("entering trie_leaf_remove(%p)\n", l);
if (tp) {
put_child(tp, get_index(l->key, tp), NULL);
trie_rebalance(t, tp);
} else {
RCU_INIT_POINTER(t->trie, NULL);
}
node_free(l);
}
/*
* Caller must hold RTNL.
*/
int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
{
struct trie *t = (struct trie *) tb->tb_data;
u32 key, mask;
int plen = cfg->fc_dst_len;
u8 tos = cfg->fc_tos;
struct fib_alias *fa, *fa_to_delete;
struct list_head *fa_head;
struct tnode *l;
struct leaf_info *li;
if (plen > 32)
return -EINVAL;
key = ntohl(cfg->fc_dst);
mask = ntohl(inet_make_mask(plen));
if (key & ~mask)
return -EINVAL;
key = key & mask;
l = fib_find_node(t, key);
if (!l)
return -ESRCH;
li = find_leaf_info(l, plen);
if (!li)
return -ESRCH;
fa_head = &li->falh;
fa = fib_find_alias(fa_head, tos, 0);
if (!fa)
return -ESRCH;
pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
fa_to_delete = NULL;
fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
list_for_each_entry_continue(fa, fa_head, fa_list) {
struct fib_info *fi = fa->fa_info;
if (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;
fa = fa_to_delete;
rtmsg_fib(RTM_DELROUTE, htonl(key), fa, plen, tb->tb_id,
&cfg->fc_nlinfo, 0);
list_del_rcu(&fa->fa_list);
if (!plen)
tb->tb_num_default--;
if (list_empty(fa_head)) {
remove_leaf_info(l, li);
free_leaf_info(li);
}
if (hlist_empty(&l->list))
trie_leaf_remove(t, l);
if (fa->fa_state & FA_S_ACCESSED)
rt_cache_flush(cfg->fc_nlinfo.nl_net);
fib_release_info(fa->fa_info);
alias_free_mem_rcu(fa);
return 0;
}
static int trie_flush_list(struct list_head *head)
{
struct fib_alias *fa, *fa_node;
int found = 0;
list_for_each_entry_safe(fa, fa_node, head, fa_list) {
struct fib_info *fi = fa->fa_info;
if (fi && (fi->fib_flags & RTNH_F_DEAD)) {
list_del_rcu(&fa->fa_list);
fib_release_info(fa->fa_info);
alias_free_mem_rcu(fa);
found++;
}
}
return found;
}
static int trie_flush_leaf(struct tnode *l)
{
int found = 0;
struct hlist_head *lih = &l->list;
struct hlist_node *tmp;
struct leaf_info *li = NULL;
unsigned char plen = KEYLENGTH;
hlist_for_each_entry_safe(li, tmp, lih, hlist) {
found += trie_flush_list(&li->falh);
if (list_empty(&li->falh)) {
hlist_del_rcu(&li->hlist);
free_leaf_info(li);
continue;
}
plen = li->plen;
}
l->slen = KEYLENGTH - plen;
return found;
}
/*
* Scan for the next right leaf starting at node p->child[idx]
* Since we have back pointer, no recursion necessary.
*/
static struct tnode *leaf_walk_rcu(struct tnode *p, struct tnode *c)
{
do {
unsigned long idx = c ? idx = get_index(c->key, p) + 1 : 0;
while (idx < tnode_child_length(p)) {
c = tnode_get_child_rcu(p, idx++);
if (!c)
continue;
if (IS_LEAF(c))
return c;
/* Rescan start scanning in new node */
p = c;
idx = 0;
}
/* Node empty, walk back up to parent */
c = p;
} while ((p = node_parent_rcu(c)) != NULL);
return NULL; /* Root of trie */
}
static struct tnode *trie_firstleaf(struct trie *t)
{
struct tnode *n = rcu_dereference_rtnl(t->trie);
if (!n)
return NULL;
if (IS_LEAF(n)) /* trie is just a leaf */
return n;
return leaf_walk_rcu(n, NULL);
}
static struct tnode *trie_nextleaf(struct tnode *l)
{
struct tnode *p = node_parent_rcu(l);
if (!p)
return NULL; /* trie with just one leaf */
return leaf_walk_rcu(p, l);
}
static struct tnode *trie_leafindex(struct trie *t, int index)
{
struct tnode *l = trie_firstleaf(t);
while (l && index-- > 0)
l = trie_nextleaf(l);
return l;
}
/*
* Caller must hold RTNL.
*/
int fib_table_flush(struct fib_table *tb)
{
struct trie *t = (struct trie *) tb->tb_data;
struct tnode *l, *ll = NULL;
int found = 0;
for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {
found += trie_flush_leaf(l);
if (ll) {
if (hlist_empty(&ll->list))
trie_leaf_remove(t, ll);
else
leaf_pull_suffix(ll);
}
ll = l;
}
if (ll) {
if (hlist_empty(&ll->list))
trie_leaf_remove(t, ll);
else
leaf_pull_suffix(ll);
}
pr_debug("trie_flush found=%d\n", found);
return found;
}
void fib_free_table(struct fib_table *tb)
{
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie *t = (struct trie *)tb->tb_data;
free_percpu(t->stats);
#endif /* CONFIG_IP_FIB_TRIE_STATS */
kfree(tb);
}
static int fn_trie_dump_fa(t_key key, int plen, struct list_head *fah,
struct fib_table *tb,
struct sk_buff *skb, struct netlink_callback *cb)
{
int i, s_i;
struct fib_alias *fa;
__be32 xkey = htonl(key);
s_i = cb->args[5];
i = 0;
/* rcu_read_lock is hold by caller */
list_for_each_entry_rcu(fa, fah, fa_list) {
if (i < s_i) {
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,
plen,
fa->fa_tos,
fa->fa_info, NLM_F_MULTI) < 0) {
cb->args[5] = i;
return -1;
}
i++;
}
cb->args[5] = i;
return skb->len;
}
static int fn_trie_dump_leaf(struct tnode *l, struct fib_table *tb,
struct sk_buff *skb, struct netlink_callback *cb)
{
struct leaf_info *li;
int i, s_i;
s_i = cb->args[4];
i = 0;
/* rcu_read_lock is hold by caller */
hlist_for_each_entry_rcu(li, &l->list, hlist) {
if (i < s_i) {
i++;
continue;
}
if (i > s_i)
cb->args[5] = 0;
if (list_empty(&li->falh))
continue;
if (fn_trie_dump_fa(l->key, li->plen, &li->falh, tb, skb, cb) < 0) {
cb->args[4] = i;
return -1;
}
i++;
}
cb->args[4] = i;
return skb->len;
}
int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct tnode *l;
struct trie *t = (struct trie *) tb->tb_data;
t_key key = cb->args[2];
int count = cb->args[3];
rcu_read_lock();
/* Dump starting at last key.
* Note: 0.0.0.0/0 (ie default) is first key.
*/
if (count == 0)
l = trie_firstleaf(t);
else {
/* Normally, continue from last key, but if that is missing
* fallback to using slow rescan
*/
l = fib_find_node(t, key);
if (!l)
l = trie_leafindex(t, count);
}
while (l) {
cb->args[2] = l->key;
if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
cb->args[3] = count;
rcu_read_unlock();
return -1;
}
++count;
l = trie_nextleaf(l);
memset(&cb->args[4], 0,
sizeof(cb->args) - 4*sizeof(cb->args[0]));
}
cb->args[3] = count;
rcu_read_unlock();
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",
max(sizeof(struct tnode),
sizeof(struct leaf_info)),
0, SLAB_PANIC, NULL);
}
struct fib_table *fib_trie_table(u32 id)
{
struct fib_table *tb;
struct trie *t;
tb = kmalloc(sizeof(struct fib_table) + sizeof(struct trie),
GFP_KERNEL);
if (tb == NULL)
return NULL;
tb->tb_id = id;
tb->tb_default = -1;
tb->tb_num_default = 0;
t = (struct trie *) tb->tb_data;
RCU_INIT_POINTER(t->trie, NULL);
#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 tnode *tnode;
unsigned int index;
unsigned int depth;
};
static struct tnode *fib_trie_get_next(struct fib_trie_iter *iter)
{
unsigned long cindex = iter->index;
struct tnode *tn = iter->tnode;
struct tnode *p;
/* A single entry routing table */
if (!tn)
return NULL;
pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
iter->tnode, iter->index, iter->depth);
rescan:
while (cindex < tnode_child_length(tn)) {
struct tnode *n = tnode_get_child_rcu(tn, cindex);
if (n) {
if (IS_LEAF(n)) {
iter->tnode = tn;
iter->index = cindex + 1;
} else {
/* push down one level */
iter->tnode = n;
iter->index = 0;
++iter->depth;
}
return n;
}
++cindex;
}
/* Current node exhausted, pop back up */
p = node_parent_rcu(tn);
if (p) {
cindex = get_index(tn->key, p) + 1;
tn = p;
--iter->depth;
goto rescan;
}
/* got root? */
return NULL;
}
static struct tnode *fib_trie_get_first(struct fib_trie_iter *iter,
struct trie *t)
{
struct tnode *n;
if (!t)
return NULL;
n = rcu_dereference(t->trie);
if (!n)
return NULL;
if (IS_TNODE(n)) {
iter->tnode = n;
iter->index = 0;
iter->depth = 1;
} else {
iter->tnode = NULL;
iter->index = 0;
iter->depth = 0;
}
return n;
}
static void trie_collect_stats(struct trie *t, struct trie_stat *s)
{
struct tnode *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 leaf_info *li;
s->leaves++;
s->totdepth += iter.depth;
if (iter.depth > s->maxdepth)
s->maxdepth = iter.depth;
hlist_for_each_entry_rcu(li, &n->list, hlist)
++s->prefixes;
} else {
s->tnodes++;
if (n->bits < MAX_STAT_DEPTH)
s->nodesizes[n->bits]++;
s->nullpointers += 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 = sizeof(struct tnode) * stat->leaves;
seq_printf(seq, "\tPrefixes: %u\n", stat->prefixes);
bytes += sizeof(struct leaf_info) * stat->prefixes;
seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
bytes += sizeof(struct tnode) * 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 tnode *) * 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",
sizeof(struct tnode), sizeof(struct tnode));
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 tnode *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 tnode *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 tnode *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 tnode *n = v;
if (!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,
n->full_children, n->empty_children);
} else {
struct leaf_info *li;
__be32 val = htonl(n->key);
seq_indent(seq, iter->depth);
seq_printf(seq, " |-- %pI4\n", &val);
hlist_for_each_entry_rcu(li, &n->list, hlist) {
struct fib_alias *fa;
list_for_each_entry_rcu(fa, &li->falh, fa_list) {
char buf1[32], buf2[32];
seq_indent(seq, iter->depth+1);
seq_printf(seq, " /%d %s %s", li->plen,
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 trie *main_trie;
loff_t pos;
t_key key;
};
static struct tnode *fib_route_get_idx(struct fib_route_iter *iter, loff_t pos)
{
struct tnode *l = NULL;
struct trie *t = iter->main_trie;
/* use cache location of last found key */
if (iter->pos > 0 && pos >= iter->pos && (l = fib_find_node(t, iter->key)))
pos -= iter->pos;
else {
iter->pos = 0;
l = trie_firstleaf(t);
}
while (l && pos-- > 0) {
iter->pos++;
l = trie_nextleaf(l);
}
if (l)
iter->key = pos; /* 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;
rcu_read_lock();
tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
if (!tb)
return NULL;
iter->main_trie = (struct trie *) tb->tb_data;
if (*pos == 0)
return SEQ_START_TOKEN;
else
return fib_route_get_idx(iter, *pos - 1);
}
static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct fib_route_iter *iter = seq->private;
struct tnode *l = v;
++*pos;
if (v == SEQ_START_TOKEN) {
iter->pos = 0;
l = trie_firstleaf(iter->main_trie);
} else {
iter->pos++;
l = trie_nextleaf(l);
}
if (l)
iter->key = l->key;
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 tnode *l = v;
struct leaf_info *li;
if (v == SEQ_START_TOKEN) {
seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
"\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
"\tWindow\tIRTT");
return 0;
}
hlist_for_each_entry_rcu(li, &l->list, hlist) {
struct fib_alias *fa;
__be32 mask, prefix;
mask = inet_make_mask(li->plen);
prefix = htonl(l->key);
list_for_each_entry_rcu(fa, &li->falh, fa_list) {
const struct fib_info *fi = fa->fa_info;
unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
if (fa->fa_type == RTN_BROADCAST
|| fa->fa_type == RTN_MULTICAST)
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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