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Commit 554cfb7e authored by YOSHIFUJI Hideaki's avatar YOSHIFUJI Hideaki Committed by David S. Miller
Browse files

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



And prepare for more advanced router selection.

Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 519fbd87

include/net/ip6_route.h

+0 −2
Original line number Diff line number Diff line
@@ -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,

net/ipv6/ip6_fib.c

+0 −1
Original line number Diff line number Diff line
@@ -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++;

net/ipv6/route.c

+69 −128
Original line number Diff line number Diff line
@@ -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;



	for (sprt = rt; sprt; sprt = sprt->u.next) {

		struct neighbour *neigh;

	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;

}



		if (!oif ||

		    (sprt->rt6i_dev &&

		     sprt->rt6i_dev->ifindex == oif))

			m += 8;

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 (rt6_check_expired(sprt))

			continue;

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 (sprt == rt6_dflt_pointer)

			m += 4;

	RT6_TRACE("%s(head=%p(*head=%p), oif=%d)\n",

		  __FUNCTION__, head, head ? *head : NULL, oif);



		if ((neigh = sprt->rt6i_nexthop) != NULL) {

			read_lock_bh(&neigh->lock);

			switch (neigh->nud_state) {

			case NUD_REACHABLE:

				m += 3;

				break;

	for (rt = rt0, metric = rt0->rt6i_metric;

	     rt && rt->rt6i_metric == metric;

	     rt = rt->u.next) {

		int m;



			case NUD_STALE:

			case NUD_DELAY:

			case NUD_PROBE:

				m += 2;

				break;

		if (rt6_check_expired(rt))

			continue;



			case NUD_NOARP:

			case NUD_PERMANENT:

				m += 1;

				break;

		last = rt;



			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) {

		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 @@ struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl) 
		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 @@ void rt6_purge_dflt_routers(void) 
		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);