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linux_dsm_epyc7002/net/ipv4/fib_trie.c
Alexander Duyck 69fa57b1e4 fib_trie: Fix RCU bug and merge similar bits of inflate/halve 
This patch addresses two issues.

The first issue is the fact that I believe I had the RCU freeing sequence
slightly out of order.  As a result we could get into an issue if a caller
went into a child of a child of the new node, then backtraced into the to be
freed parent, and then attempted to access a child of a child that may have
been consumed in a resize of one of the new nodes children.  To resolve this I
have moved the resize after we have freed the oldtnode.  The only side effect
of this is that we will now be calling resize on more nodes in the case of
inflate due to the fact that we don't have a good way to test to see if a
full_tnode on the new node was there before or after the allocation.  This
should have minimal impact however since the node should already be
correctly size so it is just the cost of calling should_inflate that we
will be taking on the node which is only a couple of cycles.

The second issue is the fact that inflate and halve were essentially doing
the same thing after the new node was added to the trie replacing the old
one.  As such it wasn't really necessary to keep the code in both functions
so I have split it out into two other functions, called replace and
update_children.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-25 14:47:15 -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))
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 {
unsigned int full_children; /* KEYLENGTH bits needed */
unsigned int empty_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 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[1 << 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;
tn->full_children = 0;
tn->empty_children = 1<<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 */
if (n == NULL && chi != NULL)
tn->empty_children++;
else if (n != NULL && chi == NULL)
tn->empty_children--;
/* 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 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->full_children;
used -= tn->empty_children;
return 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;
return (tn->bits > 1) && ((100 * used) < threshold);
}
#define MAX_WORK 10
static void resize(struct trie *t, struct tnode *tn)
{
struct tnode *tp = node_parent(tn), *n = NULL;
struct tnode __rcu **cptr;
int 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));
/* No children */
if (tn->empty_children > (tnode_child_length(tn) - 1))
goto no_children;
/* One child */
if (tn->empty_children == (tnode_child_length(tn) - 1))
goto one_child;
/* Double as long as the resulting node has a number of
* nonempty nodes that are above the threshold.
*/
max_work = MAX_WORK;
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;
}
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.
*/
max_work = MAX_WORK;
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;
}
tn = rtnl_dereference(*cptr);
}
/* Only one child remains */
if (tn->empty_children == (tnode_child_length(tn) - 1)) {
unsigned long i;
one_child:
for (i = tnode_child_length(tn); !n && i;)
n = tnode_get_child(tn, --i);
no_children:
/* compress one level */
put_child_root(tp, t, tn->key, n);
node_set_parent(n, tp);
/* drop dead node */
tnode_free_init(tn);
tnode_free(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)
{
struct hlist_node *prev;
/* record the location of the pointer to this object */
prev = rtnl_dereference(hlist_pprev_rcu(&old->hlist));
/* remove the leaf info from the list */
hlist_del_rcu(&old->hlist);
/* 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->list))
return;
/* if we removed the tail then we need to update slen */
if (!rcu_access_pointer(hlist_next_rcu(prev))) {
struct leaf_info *li = hlist_entry(prev, typeof(*li), hlist);
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 (!rcu_access_pointer(hlist_next_rcu(&new->hlist))) {
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;
}
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;
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);
}
}
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 && hlist_empty(&ll->list))
trie_leaf_remove(t, ll);
ll = l;
}
if (ll && hlist_empty(&ll->list))
trie_leaf_remove(t, 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 {
unsigned long i;
s->tnodes++;
if (n->bits < MAX_STAT_DEPTH)
s->nodesizes[n->bits]++;
for (i = tnode_child_length(n); i--;) {
if (!rcu_access_pointer(n->child[i]))
s->nullpointers++;
}
}
}
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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