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authorYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>2006-03-20 17:00:26 -0800
committerDavid S. Miller <davem@davemloft.net>2006-03-20 17:00:26 -0800
commit554cfb7ee5d4f2d0edb280e66e4a2db1906a8300 (patch)
tree586bca2143a23157ac2619b1c211144662ddf8f3 /net/ipv6
parent519fbd8715ce6413ec8e122bf02f09b0e49d3ca5 (diff)
downloadblackbird-op-linux-554cfb7ee5d4f2d0edb280e66e4a2db1906a8300.tar.gz
blackbird-op-linux-554cfb7ee5d4f2d0edb280e66e4a2db1906a8300.zip
[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>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_fib.c1
-rw-r--r--net/ipv6/route.c197
2 files changed, 69 insertions, 129 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 1bf6d9a769e6..2cb6149349bf 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -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++;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 6a4019a4ca89..f71e2365b43d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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);
+static int inline rt6_check_dev(struct rt6_info *rt, int oif)
+{
+ 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;
+}
-void rt6_reset_dflt_pointer(struct rt6_info *rt)
+static int inline rt6_check_neigh(struct rt6_info *rt)
{
- 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;
+ 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);
}
- spin_unlock_bh(&rt6_dflt_lock);
+ return m;
}
-/* Default Router Selection (RFC 2461 6.3.6) */
-static struct rt6_info *rt6_best_dflt(struct rt6_info *rt, int oif)
+static int rt6_score_route(struct rt6_info *rt, int oif,
+ int strict)
{
- struct rt6_info *match = NULL;
- struct rt6_info *sprt;
- int mpri = 0;
+ 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;
+}
- for (sprt = rt; sprt; sprt = sprt->u.next) {
- struct neighbour *neigh;
- int m = 0;
+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 (!oif ||
- (sprt->rt6i_dev &&
- sprt->rt6i_dev->ifindex == oif))
- m += 8;
+ RT6_TRACE("%s(head=%p(*head=%p), oif=%d)\n",
+ __FUNCTION__, head, head ? *head : NULL, oif);
- if (rt6_check_expired(sprt))
+ 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;
-
- 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 {
+ last = rt;
+
+ 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) {
- if (rt6_dflt_pointer != match)
- RT6_TRACE("changed default router: %p->%p\n",
- rt6_dflt_pointer, match);
- rt6_dflt_pointer = match;
+ 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;
}
- spin_unlock(&rt6_dflt_lock);
- 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;
- }
- }
+ RT6_TRACE("%s() => %p, score=%d\n",
+ __FUNCTION__, match, mpri);
- 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);
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