Commit c92b9655 authored by Julian Anastasov's avatar Julian Anastasov Committed by David S. Miller
Browse files

ipv4: Add FLOWI_FLAG_KNOWN_NH 



Add flag to request that output route should be
returned with known rt_gateway, in case we want to use
it as nexthop for neighbour resolving.

	The returned route can be cached as follows:

- in NH exception: because the cached routes are not shared
	with other destinations
- in FIB NH: when using gateway because all destinations for
	NH share same gateway

	As last option, to return rt_gateway!=0 we have to
set DST_NOCACHE.

Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 155e8336

include/net/flow.h

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ struct flowi_common { 
	__u8	flowic_flags;

#define FLOWI_FLAG_ANYSRC		0x01

#define FLOWI_FLAG_CAN_SLEEP		0x02

#define FLOWI_FLAG_KNOWN_NH		0x04

	__u32	flowic_secid;

};

net/ipv4/route.c

+17 −4
Original line number Diff line number Diff line
@@ -1762,6 +1762,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res, 
	struct in_device *in_dev;

	u16 type = res->type;

	struct rtable *rth;

	bool do_cache;



	in_dev = __in_dev_get_rcu(dev_out);

	if (!in_dev)
@@ -1798,24 +1799,36 @@ static struct rtable *__mkroute_output(const struct fib_result *res, 
	}



	fnhe = NULL;

	do_cache = fi != NULL;

	if (fi) {

		struct rtable __rcu **prth;

		struct fib_nh *nh = &FIB_RES_NH(*res);



		fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);

		fnhe = find_exception(nh, fl4->daddr);

		if (fnhe)

			prth = &fnhe->fnhe_rth;

		else

			prth = __this_cpu_ptr(FIB_RES_NH(*res).nh_pcpu_rth_output);

		else {

			if (unlikely(fl4->flowi4_flags &

				     FLOWI_FLAG_KNOWN_NH &&

				     !(nh->nh_gw &&

				       nh->nh_scope == RT_SCOPE_LINK))) {

				do_cache = false;

				goto add;

			}

			prth = __this_cpu_ptr(nh->nh_pcpu_rth_output);

		}

		rth = rcu_dereference(*prth);

		if (rt_cache_valid(rth)) {

			dst_hold(&rth->dst);

			return rth;

		}

	}



add:

	rth = rt_dst_alloc(dev_out,

			   IN_DEV_CONF_GET(in_dev, NOPOLICY),

			   IN_DEV_CONF_GET(in_dev, NOXFRM),

			   fi);

			   do_cache);

	if (!rth)

		return ERR_PTR(-ENOBUFS);

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