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

1227 строки
24 KiB
C
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/*
* Linux INET6 implementation
* Forwarding Information Database
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*
* $Id: ip6_fib.c,v 1.25 2001/10/31 21:55:55 davem Exp $
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
/*
* Changes:
* Yuji SEKIYA @USAGI: Support default route on router node;
* remove ip6_null_entry from the top of
* routing table.
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/net.h>
#include <linux/route.h>
#include <linux/netdevice.h>
#include <linux/in6.h>
#include <linux/init.h>
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
#endif
#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/ip6_fib.h>
#include <net/ip6_route.h>
#define RT6_DEBUG 2
#if RT6_DEBUG >= 3
#define RT6_TRACE(x...) printk(KERN_DEBUG x)
#else
#define RT6_TRACE(x...) do { ; } while (0)
#endif
struct rt6_statistics rt6_stats;
static kmem_cache_t * fib6_node_kmem __read_mostly;
enum fib_walk_state_t
{
#ifdef CONFIG_IPV6_SUBTREES
FWS_S,
#endif
FWS_L,
FWS_R,
FWS_C,
FWS_U
};
struct fib6_cleaner_t
{
struct fib6_walker_t w;
int (*func)(struct rt6_info *, void *arg);
void *arg;
};
DEFINE_RWLOCK(fib6_walker_lock);
#ifdef CONFIG_IPV6_SUBTREES
#define FWS_INIT FWS_S
#define SUBTREE(fn) ((fn)->subtree)
#else
#define FWS_INIT FWS_L
#define SUBTREE(fn) NULL
#endif
static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt);
static struct fib6_node * fib6_repair_tree(struct fib6_node *fn);
/*
* A routing update causes an increase of the serial number on the
* affected subtree. This allows for cached routes to be asynchronously
* tested when modifications are made to the destination cache as a
* result of redirects, path MTU changes, etc.
*/
static __u32 rt_sernum;
static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0);
struct fib6_walker_t fib6_walker_list = {
.prev = &fib6_walker_list,
.next = &fib6_walker_list,
};
#define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next)
static __inline__ u32 fib6_new_sernum(void)
{
u32 n = ++rt_sernum;
if ((__s32)n <= 0)
rt_sernum = n = 1;
return n;
}
/*
* Auxiliary address test functions for the radix tree.
*
* These assume a 32bit processor (although it will work on
* 64bit processors)
*/
/*
* test bit
*/
static __inline__ int addr_bit_set(void *token, int fn_bit)
{
__u32 *addr = token;
return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5];
}
/*
* find the first different bit between two addresses
* length of address must be a multiple of 32bits
*/
static __inline__ int addr_diff(void *token1, void *token2, int addrlen)
{
__u32 *a1 = token1;
__u32 *a2 = token2;
int i;
addrlen >>= 2;
for (i = 0; i < addrlen; i++) {
__u32 xb;
xb = a1[i] ^ a2[i];
if (xb) {
int j = 31;
xb = ntohl(xb);
while ((xb & (1 << j)) == 0)
j--;
return (i * 32 + 31 - j);
}
}
/*
* we should *never* get to this point since that
* would mean the addrs are equal
*
* However, we do get to it 8) And exacly, when
* addresses are equal 8)
*
* ip route add 1111::/128 via ...
* ip route add 1111::/64 via ...
* and we are here.
*
* Ideally, this function should stop comparison
* at prefix length. It does not, but it is still OK,
* if returned value is greater than prefix length.
* --ANK (980803)
*/
return addrlen<<5;
}
static __inline__ struct fib6_node * node_alloc(void)
{
struct fib6_node *fn;
if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL)
memset(fn, 0, sizeof(struct fib6_node));
return fn;
}
static __inline__ void node_free(struct fib6_node * fn)
{
kmem_cache_free(fib6_node_kmem, fn);
}
static __inline__ void rt6_release(struct rt6_info *rt)
{
if (atomic_dec_and_test(&rt->rt6i_ref))
dst_free(&rt->u.dst);
}
/*
* Routing Table
*
* return the appropriate node for a routing tree "add" operation
* by either creating and inserting or by returning an existing
* node.
*/
static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
int addrlen, int plen,
int offset)
{
struct fib6_node *fn, *in, *ln;
struct fib6_node *pn = NULL;
struct rt6key *key;
int bit;
int dir = 0;
__u32 sernum = fib6_new_sernum();
RT6_TRACE("fib6_add_1\n");
/* insert node in tree */
fn = root;
do {
key = (struct rt6key *)((u8 *)fn->leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
goto insert_above;
/*
* Exact match ?
*/
if (plen == fn->fn_bit) {
/* clean up an intermediate node */
if ((fn->fn_flags & RTN_RTINFO) == 0) {
rt6_release(fn->leaf);
fn->leaf = NULL;
}
fn->fn_sernum = sernum;
return fn;
}
/*
* We have more bits to go
*/
/* Try to walk down on tree. */
fn->fn_sernum = sernum;
dir = addr_bit_set(addr, fn->fn_bit);
pn = fn;
fn = dir ? fn->right: fn->left;
} while (fn);
/*
* We walked to the bottom of tree.
* Create new leaf node without children.
*/
ln = node_alloc();
if (ln == NULL)
return NULL;
ln->fn_bit = plen;
ln->parent = pn;
ln->fn_sernum = sernum;
if (dir)
pn->right = ln;
else
pn->left = ln;
return ln;
insert_above:
/*
* split since we don't have a common prefix anymore or
* we have a less significant route.
* we've to insert an intermediate node on the list
* this new node will point to the one we need to create
* and the current
*/
pn = fn->parent;
/* find 1st bit in difference between the 2 addrs.
See comment in addr_diff: bit may be an invalid value,
but if it is >= plen, the value is ignored in any case.
*/
bit = addr_diff(addr, &key->addr, addrlen);
/*
* (intermediate)[in]
* / \
* (new leaf node)[ln] (old node)[fn]
*/
if (plen > bit) {
in = node_alloc();
ln = node_alloc();
if (in == NULL || ln == NULL) {
if (in)
node_free(in);
if (ln)
node_free(ln);
return NULL;
}
/*
* new intermediate node.
* RTN_RTINFO will
* be off since that an address that chooses one of
* the branches would not match less specific routes
* in the other branch
*/
in->fn_bit = bit;
in->parent = pn;
in->leaf = fn->leaf;
atomic_inc(&in->leaf->rt6i_ref);
in->fn_sernum = sernum;
/* update parent pointer */
if (dir)
pn->right = in;
else
pn->left = in;
ln->fn_bit = plen;
ln->parent = in;
fn->parent = in;
ln->fn_sernum = sernum;
if (addr_bit_set(addr, bit)) {
in->right = ln;
in->left = fn;
} else {
in->left = ln;
in->right = fn;
}
} else { /* plen <= bit */
/*
* (new leaf node)[ln]
* / \
* (old node)[fn] NULL
*/
ln = node_alloc();
if (ln == NULL)
return NULL;
ln->fn_bit = plen;
ln->parent = pn;
ln->fn_sernum = sernum;
if (dir)
pn->right = ln;
else
pn->left = ln;
if (addr_bit_set(&key->addr, plen))
ln->right = fn;
else
ln->left = fn;
fn->parent = ln;
}
return ln;
}
/*
* Insert routing information in a node.
*/
static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
struct nlmsghdr *nlh, struct netlink_skb_parms *req)
{
struct rt6_info *iter = NULL;
struct rt6_info **ins;
ins = &fn->leaf;
if (fn->fn_flags&RTN_TL_ROOT &&
fn->leaf == &ip6_null_entry &&
!(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){
fn->leaf = rt;
rt->u.next = NULL;
goto out;
}
for (iter = fn->leaf; iter; iter=iter->u.next) {
/*
* Search for duplicates
*/
if (iter->rt6i_metric == rt->rt6i_metric) {
/*
* Same priority level
*/
if (iter->rt6i_dev == rt->rt6i_dev &&
iter->rt6i_idev == rt->rt6i_idev &&
ipv6_addr_equal(&iter->rt6i_gateway,
&rt->rt6i_gateway)) {
if (!(iter->rt6i_flags&RTF_EXPIRES))
return -EEXIST;
iter->rt6i_expires = rt->rt6i_expires;
if (!(rt->rt6i_flags&RTF_EXPIRES)) {
iter->rt6i_flags &= ~RTF_EXPIRES;
iter->rt6i_expires = 0;
}
return -EEXIST;
}
}
if (iter->rt6i_metric > rt->rt6i_metric)
break;
ins = &iter->u.next;
}
/*
* insert node
*/
out:
rt->u.next = iter;
*ins = rt;
rt->rt6i_node = fn;
atomic_inc(&rt->rt6i_ref);
inet6_rt_notify(RTM_NEWROUTE, rt, nlh, req);
rt6_stats.fib_rt_entries++;
if ((fn->fn_flags & RTN_RTINFO) == 0) {
rt6_stats.fib_route_nodes++;
fn->fn_flags |= RTN_RTINFO;
}
return 0;
}
static __inline__ void fib6_start_gc(struct rt6_info *rt)
{
if (ip6_fib_timer.expires == 0 &&
(rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
}
void fib6_force_start_gc(void)
{
if (ip6_fib_timer.expires == 0)
mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
}
/*
* Add routing information to the routing tree.
* <destination addr>/<source addr>
* with source addr info in sub-trees
*/
int fib6_add(struct fib6_node *root, struct rt6_info *rt,
struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
{
struct fib6_node *fn;
int err = -ENOMEM;
fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
if (fn == NULL)
goto out;
#ifdef CONFIG_IPV6_SUBTREES
if (rt->rt6i_src.plen) {
struct fib6_node *sn;
if (fn->subtree == NULL) {
struct fib6_node *sfn;
/*
* Create subtree.
*
* fn[main tree]
* |
* sfn[subtree root]
* \
* sn[new leaf node]
*/
/* Create subtree root node */
sfn = node_alloc();
if (sfn == NULL)
goto st_failure;
sfn->leaf = &ip6_null_entry;
atomic_inc(&ip6_null_entry.rt6i_ref);
sfn->fn_flags = RTN_ROOT;
sfn->fn_sernum = fib6_new_sernum();
/* Now add the first leaf node to new subtree */
sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
sizeof(struct in6_addr), rt->rt6i_src.plen,
offsetof(struct rt6_info, rt6i_src));
if (sn == NULL) {
/* If it is failed, discard just allocated
root, and then (in st_failure) stale node
in main tree.
*/
node_free(sfn);
goto st_failure;
}
/* Now link new subtree to main tree */
sfn->parent = fn;
fn->subtree = sfn;
if (fn->leaf == NULL) {
fn->leaf = rt;
atomic_inc(&rt->rt6i_ref);
}
} else {
sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
sizeof(struct in6_addr), rt->rt6i_src.plen,
offsetof(struct rt6_info, rt6i_src));
if (sn == NULL)
goto st_failure;
}
fn = sn;
}
#endif
err = fib6_add_rt2node(fn, rt, nlh, req);
if (err == 0) {
fib6_start_gc(rt);
if (!(rt->rt6i_flags&RTF_CACHE))
fib6_prune_clones(fn, rt);
}
out:
if (err)
dst_free(&rt->u.dst);
return err;
#ifdef CONFIG_IPV6_SUBTREES
/* Subtree creation failed, probably main tree node
is orphan. If it is, shoot it.
*/
st_failure:
if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
fib6_repair_tree(fn);
dst_free(&rt->u.dst);
return err;
#endif
}
/*
* Routing tree lookup
*
*/
struct lookup_args {
int offset; /* key offset on rt6_info */
struct in6_addr *addr; /* search key */
};
static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
struct lookup_args *args)
{
struct fib6_node *fn;
int dir;
/*
* Descend on a tree
*/
fn = root;
for (;;) {
struct fib6_node *next;
dir = addr_bit_set(args->addr, fn->fn_bit);
next = dir ? fn->right : fn->left;
if (next) {
fn = next;
continue;
}
break;
}
while ((fn->fn_flags & RTN_ROOT) == 0) {
#ifdef CONFIG_IPV6_SUBTREES
if (fn->subtree) {
struct fib6_node *st;
struct lookup_args *narg;
narg = args + 1;
if (narg->addr) {
st = fib6_lookup_1(fn->subtree, narg);
if (st && !(st->fn_flags & RTN_ROOT))
return st;
}
}
#endif
if (fn->fn_flags & RTN_RTINFO) {
struct rt6key *key;
key = (struct rt6key *) ((u8 *) fn->leaf +
args->offset);
if (ipv6_prefix_equal(&key->addr, args->addr, key->plen))
return fn;
}
fn = fn->parent;
}
return NULL;
}
struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
struct in6_addr *saddr)
{
struct lookup_args args[2];
struct fib6_node *fn;
args[0].offset = offsetof(struct rt6_info, rt6i_dst);
args[0].addr = daddr;
#ifdef CONFIG_IPV6_SUBTREES
args[1].offset = offsetof(struct rt6_info, rt6i_src);
args[1].addr = saddr;
#endif
fn = fib6_lookup_1(root, args);
if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
fn = root;
return fn;
}
/*
* Get node with specified destination prefix (and source prefix,
* if subtrees are used)
*/
static struct fib6_node * fib6_locate_1(struct fib6_node *root,
struct in6_addr *addr,
int plen, int offset)
{
struct fib6_node *fn;
for (fn = root; fn ; ) {
struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
/*
* Prefix match
*/
if (plen < fn->fn_bit ||
!ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
return NULL;
if (plen == fn->fn_bit)
return fn;
/*
* We have more bits to go
*/
if (addr_bit_set(addr, fn->fn_bit))
fn = fn->right;
else
fn = fn->left;
}
return NULL;
}
struct fib6_node * fib6_locate(struct fib6_node *root,
struct in6_addr *daddr, int dst_len,
struct in6_addr *saddr, int src_len)
{
struct fib6_node *fn;
fn = fib6_locate_1(root, daddr, dst_len,
offsetof(struct rt6_info, rt6i_dst));
#ifdef CONFIG_IPV6_SUBTREES
if (src_len) {
BUG_TRAP(saddr!=NULL);
if (fn == NULL)
fn = fn->subtree;
if (fn)
fn = fib6_locate_1(fn, saddr, src_len,
offsetof(struct rt6_info, rt6i_src));
}
#endif
if (fn && fn->fn_flags&RTN_RTINFO)
return fn;
return NULL;
}
/*
* Deletion
*
*/
static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
{
if (fn->fn_flags&RTN_ROOT)
return &ip6_null_entry;
while(fn) {
if(fn->left)
return fn->left->leaf;
if(fn->right)
return fn->right->leaf;
fn = SUBTREE(fn);
}
return NULL;
}
/*
* Called to trim the tree of intermediate nodes when possible. "fn"
* is the node we want to try and remove.
*/
static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
{
int children;
int nstate;
struct fib6_node *child, *pn;
struct fib6_walker_t *w;
int iter = 0;
for (;;) {
RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
iter++;
BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
BUG_TRAP(fn->leaf==NULL);
children = 0;
child = NULL;
if (fn->right) child = fn->right, children |= 1;
if (fn->left) child = fn->left, children |= 2;
if (children == 3 || SUBTREE(fn)
#ifdef CONFIG_IPV6_SUBTREES
/* Subtree root (i.e. fn) may have one child */
|| (children && fn->fn_flags&RTN_ROOT)
#endif
) {
fn->leaf = fib6_find_prefix(fn);
#if RT6_DEBUG >= 2
if (fn->leaf==NULL) {
BUG_TRAP(fn->leaf);
fn->leaf = &ip6_null_entry;
}
#endif
atomic_inc(&fn->leaf->rt6i_ref);
return fn->parent;
}
pn = fn->parent;
#ifdef CONFIG_IPV6_SUBTREES
if (SUBTREE(pn) == fn) {
BUG_TRAP(fn->fn_flags&RTN_ROOT);
SUBTREE(pn) = NULL;
nstate = FWS_L;
} else {
BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
#endif
if (pn->right == fn) pn->right = child;
else if (pn->left == fn) pn->left = child;
#if RT6_DEBUG >= 2
else BUG_TRAP(0);
#endif
if (child)
child->parent = pn;
nstate = FWS_R;
#ifdef CONFIG_IPV6_SUBTREES
}
#endif
read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
if (child == NULL) {
if (w->root == fn) {
w->root = w->node = NULL;
RT6_TRACE("W %p adjusted by delroot 1\n", w);
} else if (w->node == fn) {
RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
w->node = pn;
w->state = nstate;
}
} else {
if (w->root == fn) {
w->root = child;
RT6_TRACE("W %p adjusted by delroot 2\n", w);
}
if (w->node == fn) {
w->node = child;
if (children&2) {
RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
} else {
RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
}
}
}
}
read_unlock(&fib6_walker_lock);
node_free(fn);
if (pn->fn_flags&RTN_RTINFO || SUBTREE(pn))
return pn;
rt6_release(pn->leaf);
pn->leaf = NULL;
fn = pn;
}
}
static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
{
struct fib6_walker_t *w;
struct rt6_info *rt = *rtp;
RT6_TRACE("fib6_del_route\n");
/* Unlink it */
*rtp = rt->u.next;
rt->rt6i_node = NULL;
rt6_stats.fib_rt_entries--;
rt6_stats.fib_discarded_routes++;
/* Adjust walkers */
read_lock(&fib6_walker_lock);
FOR_WALKERS(w) {
if (w->state == FWS_C && w->leaf == rt) {
RT6_TRACE("walker %p adjusted by delroute\n", w);
w->leaf = rt->u.next;
if (w->leaf == NULL)
w->state = FWS_U;
}
}
read_unlock(&fib6_walker_lock);
rt->u.next = NULL;
if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT)
fn->leaf = &ip6_null_entry;
/* If it was last route, expunge its radix tree node */
if (fn->leaf == NULL) {
fn->fn_flags &= ~RTN_RTINFO;
rt6_stats.fib_route_nodes--;
fn = fib6_repair_tree(fn);
}
if (atomic_read(&rt->rt6i_ref) != 1) {
/* This route is used as dummy address holder in some split
* nodes. It is not leaked, but it still holds other resources,
* which must be released in time. So, scan ascendant nodes
* and replace dummy references to this route with references
* to still alive ones.
*/
while (fn) {
if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
fn->leaf = fib6_find_prefix(fn);
atomic_inc(&fn->leaf->rt6i_ref);
rt6_release(rt);
}
fn = fn->parent;
}
/* No more references are possible at this point. */
if (atomic_read(&rt->rt6i_ref) != 1) BUG();
}
inet6_rt_notify(RTM_DELROUTE, rt, nlh, req);
rt6_release(rt);
}
int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
{
struct fib6_node *fn = rt->rt6i_node;
struct rt6_info **rtp;
#if RT6_DEBUG >= 2
if (rt->u.dst.obsolete>0) {
BUG_TRAP(fn==NULL);
return -ENOENT;
}
#endif
if (fn == NULL || rt == &ip6_null_entry)
return -ENOENT;
BUG_TRAP(fn->fn_flags&RTN_RTINFO);
if (!(rt->rt6i_flags&RTF_CACHE))
fib6_prune_clones(fn, rt);
/*
* Walk the leaf entries looking for ourself
*/
for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) {
if (*rtp == rt) {
fib6_del_route(fn, rtp, nlh, _rtattr, req);
return 0;
}
}
return -ENOENT;
}
/*
* Tree traversal function.
*
* Certainly, it is not interrupt safe.
* However, it is internally reenterable wrt itself and fib6_add/fib6_del.
* It means, that we can modify tree during walking
* and use this function for garbage collection, clone pruning,
* cleaning tree when a device goes down etc. etc.
*
* It guarantees that every node will be traversed,
* and that it will be traversed only once.
*
* Callback function w->func may return:
* 0 -> continue walking.
* positive value -> walking is suspended (used by tree dumps,
* and probably by gc, if it will be split to several slices)
* negative value -> terminate walking.
*
* The function itself returns:
* 0 -> walk is complete.
* >0 -> walk is incomplete (i.e. suspended)
* <0 -> walk is terminated by an error.
*/
int fib6_walk_continue(struct fib6_walker_t *w)
{
struct fib6_node *fn, *pn;
for (;;) {
fn = w->node;
if (fn == NULL)
return 0;
if (w->prune && fn != w->root &&
fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
w->state = FWS_C;
w->leaf = fn->leaf;
}
switch (w->state) {
#ifdef CONFIG_IPV6_SUBTREES
case FWS_S:
if (SUBTREE(fn)) {
w->node = SUBTREE(fn);
continue;
}
w->state = FWS_L;
#endif
case FWS_L:
if (fn->left) {
w->node = fn->left;
w->state = FWS_INIT;
continue;
}
w->state = FWS_R;
case FWS_R:
if (fn->right) {
w->node = fn->right;
w->state = FWS_INIT;
continue;
}
w->state = FWS_C;
w->leaf = fn->leaf;
case FWS_C:
if (w->leaf && fn->fn_flags&RTN_RTINFO) {
int err = w->func(w);
if (err)
return err;
continue;
}
w->state = FWS_U;
case FWS_U:
if (fn == w->root)
return 0;
pn = fn->parent;
w->node = pn;
#ifdef CONFIG_IPV6_SUBTREES
if (SUBTREE(pn) == fn) {
BUG_TRAP(fn->fn_flags&RTN_ROOT);
w->state = FWS_L;
continue;
}
#endif
if (pn->left == fn) {
w->state = FWS_R;
continue;
}
if (pn->right == fn) {
w->state = FWS_C;
w->leaf = w->node->leaf;
continue;
}
#if RT6_DEBUG >= 2
BUG_TRAP(0);
#endif
}
}
}
int fib6_walk(struct fib6_walker_t *w)
{
int res;
w->state = FWS_INIT;
w->node = w->root;
fib6_walker_link(w);
res = fib6_walk_continue(w);
if (res <= 0)
fib6_walker_unlink(w);
return res;
}
static int fib6_clean_node(struct fib6_walker_t *w)
{
int res;
struct rt6_info *rt;
struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w;
for (rt = w->leaf; rt; rt = rt->u.next) {
res = c->func(rt, c->arg);
if (res < 0) {
w->leaf = rt;
res = fib6_del(rt, NULL, NULL, NULL);
if (res) {
#if RT6_DEBUG >= 2
printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
#endif
continue;
}
return 0;
}
BUG_TRAP(res==0);
}
w->leaf = rt;
return 0;
}
/*
* Convenient frontend to tree walker.
*
* func is called on each route.
* It may return -1 -> delete this route.
* 0 -> continue walking
*
* prune==1 -> only immediate children of node (certainly,
* ignoring pure split nodes) will be scanned.
*/
void fib6_clean_tree(struct fib6_node *root,
int (*func)(struct rt6_info *, void *arg),
int prune, void *arg)
{
struct fib6_cleaner_t c;
c.w.root = root;
c.w.func = fib6_clean_node;
c.w.prune = prune;
c.func = func;
c.arg = arg;
fib6_walk(&c.w);
}
static int fib6_prune_clone(struct rt6_info *rt, void *arg)
{
if (rt->rt6i_flags & RTF_CACHE) {
RT6_TRACE("pruning clone %p\n", rt);
return -1;
}
return 0;
}
static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
{
fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
}
/*
* Garbage collection
*/
static struct fib6_gc_args
{
int timeout;
int more;
} gc_args;
static int fib6_age(struct rt6_info *rt, void *arg)
{
unsigned long now = jiffies;
/*
* check addrconf expiration here.
* Routes are expired even if they are in use.
*
* Also age clones. Note, that clones are aged out
* only if they are not in use now.
*/
if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
if (time_after(now, rt->rt6i_expires)) {
RT6_TRACE("expiring %p\n", rt);
rt6_reset_dflt_pointer(rt);
return -1;
}
gc_args.more++;
} else if (rt->rt6i_flags & RTF_CACHE) {
if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
RT6_TRACE("aging clone %p\n", rt);
return -1;
} else if ((rt->rt6i_flags & RTF_GATEWAY) &&
(!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
RT6_TRACE("purging route %p via non-router but gateway\n",
rt);
return -1;
}
gc_args.more++;
}
return 0;
}
static DEFINE_SPINLOCK(fib6_gc_lock);
void fib6_run_gc(unsigned long dummy)
{
if (dummy != ~0UL) {
spin_lock_bh(&fib6_gc_lock);
gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval;
} else {
local_bh_disable();
if (!spin_trylock(&fib6_gc_lock)) {
mod_timer(&ip6_fib_timer, jiffies + HZ);
local_bh_enable();
return;
}
gc_args.timeout = ip6_rt_gc_interval;
}
gc_args.more = 0;
write_lock_bh(&rt6_lock);
ndisc_dst_gc(&gc_args.more);
fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL);
write_unlock_bh(&rt6_lock);
if (gc_args.more)
mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
else {
del_timer(&ip6_fib_timer);
ip6_fib_timer.expires = 0;
}
spin_unlock_bh(&fib6_gc_lock);
}
void __init fib6_init(void)
{
fib6_node_kmem = kmem_cache_create("fib6_nodes",
sizeof(struct fib6_node),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (!fib6_node_kmem)
panic("cannot create fib6_nodes cache");
}
void fib6_gc_cleanup(void)
{
del_timer(&ip6_fib_timer);
kmem_cache_destroy(fib6_node_kmem);
}
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