From c92b96553a80c1dbe2ebe128bbe37c8f98f148bf Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Mon, 8 Oct 2012 11:41:19 +0000 Subject: 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: Julian Anastasov Signed-off-by: David S. Miller --- include/net/flow.h | 1 + net/ipv4/route.c | 21 +++++++++++++++++---- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/include/net/flow.h b/include/net/flow.h index e1dd508..628e11b 100644 --- a/include/net/flow.h +++ b/include/net/flow.h @@ -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; }; diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 3a116cb..1a0da8d 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -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); -- cgit v1.1