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[IPV6]: ROUTE: Eliminate lock for default route pointer. 

And prepare for more advanced router selection.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
YOSHIFUJI Hideaki 2006-03-20 17:00:26 -08:00 committed by David S. Miller
parent 519fbd8715
commit 554cfb7ee5
3 changed files with 70 additions and 132 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/ip6_route.h
View File

@ -91,8 +91,6 @@ extern struct rt6_info * rt6_add_dflt_router(struct in6_addr *gwaddr,
extern void rt6_purge_dflt_routers(void);
extern void rt6_reset_dflt_pointer(struct rt6_info *rt);
extern void rt6_redirect(struct in6_addr *dest,
struct in6_addr *saddr,
struct neighbour *neigh,

1
net/ipv6/ip6_fib.c
View File

@ -1105,7 +1105,6 @@ static int fib6_age(struct rt6_info *rt, void *arg)
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++;

199
net/ipv6/route.c
View File

@ -74,6 +74,9 @@
#define CLONE_OFFLINK_ROUTE 0
#define RT6_SELECT_F_IFACE 0x1
#define RT6_SELECT_F_REACHABLE 0x2
static int ip6_rt_max_size = 4096;
static int ip6_rt_gc_min_interval = HZ / 2;
static int ip6_rt_gc_timeout = 60*HZ;
@ -216,148 +219,89 @@ static __inline__ struct rt6_info *rt6_device_match(struct rt6_info *rt,
}
/*
* pointer to the last default router chosen. BH is disabled locally.
* Default Router Selection (RFC 2461 6.3.6)
*/
static struct rt6_info *rt6_dflt_pointer;
static DEFINE_SPINLOCK(rt6_dflt_lock);
void rt6_reset_dflt_pointer(struct rt6_info *rt)
static int inline rt6_check_dev(struct rt6_info *rt, int oif)
{
spin_lock_bh(&rt6_dflt_lock);
if (rt == NULL || rt == rt6_dflt_pointer) {
RT6_TRACE("reset default router: %p->NULL\n", rt6_dflt_pointer);
rt6_dflt_pointer = NULL;
}
spin_unlock_bh(&rt6_dflt_lock);
struct net_device *dev = rt->rt6i_dev;
if (!oif || dev->ifindex == oif)
return 2;
if ((dev->flags & IFF_LOOPBACK) &&
rt->rt6i_idev && rt->rt6i_idev->dev->ifindex == oif)
return 1;
return 0;
}
/* Default Router Selection (RFC 2461 6.3.6) */
static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
static int inline rt6_check_neigh(struct rt6_info *rt)
{
struct rt6_info *match = NULL;
struct rt6_info *sprt;
int mpri = 0;
struct neighbour *neigh = rt->rt6i_nexthop;
int m = 0;
if (neigh) {
read_lock_bh(&neigh->lock);
if (neigh->nud_state & NUD_VALID)
m = 1;
read_unlock_bh(&neigh->lock);
}
return m;
}
for (sprt = rt; sprt; sprt = sprt->u.next) {
struct neighbour *neigh;
int m = 0;
static int rt6_score_route(struct rt6_info *rt, int oif,
int strict)
{
int m = rt6_check_dev(rt, oif);
if (!m && (strict & RT6_SELECT_F_IFACE))
return -1;
if (rt6_check_neigh(rt))
m |= 4;
else if (strict & RT6_SELECT_F_REACHABLE)
return -1;
return m;
}
if (!oif ||
(sprt->rt6i_dev &&
sprt->rt6i_dev->ifindex == oif))
m += 8;
static struct rt6_info *rt6_select(struct rt6_info **head, int oif,
int strict)
{
struct rt6_info *match = NULL, *last = NULL;
struct rt6_info *rt, *rt0 = *head;
u32 metric;
int mpri = -1;
if (rt6_check_expired(sprt))
RT6_TRACE("%s(head=%p(*head=%p), oif=%d)\n",
__FUNCTION__, head, head ? *head : NULL, oif);
for (rt = rt0, metric = rt0->rt6i_metric;
rt && rt->rt6i_metric == metric;
rt = rt->u.next) {
int m;
if (rt6_check_expired(rt))
continue;
if (sprt == rt6_dflt_pointer)
m += 4;
last = rt;
if ((neigh = sprt->rt6i_nexthop) != NULL) {
read_lock_bh(&neigh->lock);
switch (neigh->nud_state) {
case NUD_REACHABLE:
m += 3;
break;
case NUD_STALE:
case NUD_DELAY:
case NUD_PROBE:
m += 2;
break;
case NUD_NOARP:
case NUD_PERMANENT:
m += 1;
break;
case NUD_INCOMPLETE:
default:
read_unlock_bh(&neigh->lock);
continue;
}
read_unlock_bh(&neigh->lock);
} else {
m = rt6_score_route(rt, oif, strict);
if (m < 0)
continue;
}
if (m > mpri || m >= 12) {
match = sprt;
if (m > mpri) {
match = rt;
mpri = m;
if (m >= 12) {
/* we choose the last default router if it
* is in (probably) reachable state.
* If route changed, we should do pmtu
* discovery. --yoshfuji
*/
break;
}
}
}
spin_lock(&rt6_dflt_lock);
if (!match) {
/*
* No default routers are known to be reachable.
* SHOULD round robin
*/
if (rt6_dflt_pointer) {
for (sprt = rt6_dflt_pointer->u.next;
sprt; sprt = sprt->u.next) {
if (sprt->u.dst.obsolete <= 0 &&
sprt->u.dst.error == 0 &&
!rt6_check_expired(sprt)) {
match = sprt;
break;
}
}
for (sprt = rt;
!match && sprt;
sprt = sprt->u.next) {
if (sprt->u.dst.obsolete <= 0 &&
sprt->u.dst.error == 0 &&
!rt6_check_expired(sprt)) {
match = sprt;
break;
}
if (sprt == rt6_dflt_pointer)
break;
}
}
if (!match &&
(strict & RT6_SELECT_F_REACHABLE) &&
last && last != rt0) {
/* no entries matched; do round-robin */
*head = rt0->u.next;
rt0->u.next = last->u.next;
last->u.next = rt0;
}
if (match) {
if (rt6_dflt_pointer != match)
RT6_TRACE("changed default router: %p->%p\n",
rt6_dflt_pointer, match);
rt6_dflt_pointer = match;
}
spin_unlock(&rt6_dflt_lock);
RT6_TRACE("%s() => %p, score=%d\n",
__FUNCTION__, match, mpri);
if (!match) {
/*
* Last Resort: if no default routers found,
* use addrconf default route.
* We don't record this route.
*/
for (sprt = ip6_routing_table.leaf;
sprt; sprt = sprt->u.next) {
if (!rt6_check_expired(sprt) &&
(sprt->rt6i_flags & RTF_DEFAULT) &&
(!oif ||
(sprt->rt6i_dev &&
sprt->rt6i_dev->ifindex == oif))) {
match = sprt;
break;
}
}
if (!match) {
/* no default route. give up. */
match = &ip6_null_entry;
}
}
return match;
return (match ? match : &ip6_null_entry);
}
struct rt6_info *rt6_lookup(struct in6_addr *daddr, struct in6_addr *saddr,
@ -542,7 +486,7 @@ struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl)
int attempts = 3;
int err;
strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL);
strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL) ? RT6_SELECT_F_IFACE : 0;
relookup:
read_lock_bh(&rt6_lock);
@ -558,8 +502,9 @@ restart:
goto out;
}
if (rt->rt6i_flags & RTF_DEFAULT) {
if (rt->rt6i_metric >= IP6_RT_PRIO_ADDRCONF)
rt = rt6_best_dflt(rt, fl->oif);
rt = rt6_select(&fn->leaf, fl->oif, strict | RT6_SELECT_F_REACHABLE);
if (rt == &ip6_null_entry)
rt = rt6_select(&fn->leaf, fl->oif, strict);
} else {
rt = rt6_device_match(rt, fl->oif, strict);
BACKTRACK();
@ -1025,8 +970,6 @@ int ip6_del_rt(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr, struct
write_lock_bh(&rt6_lock);
rt6_reset_dflt_pointer(NULL);
err = fib6_del(rt, nlh, _rtattr, req);
dst_release(&rt->u.dst);
@ -1341,8 +1284,6 @@ restart:
if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) {
dst_hold(&rt->u.dst);
rt6_reset_dflt_pointer(NULL);
read_unlock_bh(&rt6_lock);
ip6_del_rt(rt, NULL, NULL, NULL);