linux/net/ipv6/ip6_fib.c
Jamal Hadi Salim 0d51aa80a9 [IPV6]: V6 route events reported with wrong netlink PID and seq number
Essentially netlink at the moment always reports a pid and sequence of 0
always for v6 route activities. 
To understand the repurcassions of this look at:
http://lists.quagga.net/pipermail/quagga-dev/2005-June/003507.html

While fixing this, i took the liberty to resolve the outstanding issue
of IPV6 routes inserted via ioctls to have the correct pids as well.

This patch tries to behave as close as possible to the v4 routes i.e
maintains whatever PID the socket issuing the command owns as opposed to
the process. That made the patch a little bulky.

I have tested against both netlink derived utility to add/del routes as
well as ioctl derived one. The Quagga folks have tested against quagga.
This fixes the problem and so far hasnt been detected to introduce any
new issues.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-21 13:51:04 -07:00

1227 lines
24 KiB
C

/*
* 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;
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 struct timer_list ip6_fib_timer = TIMER_INITIALIZER(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);
}