3.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Julian Anastasov <j...@ssi.bg>
[ Upstream commit c92b96553a80c1dbe2ebe128bbe37c8f98f148bf ]
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 <j...@ssi.bg>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
include/net/flow.h | 1 +
net/ipv4/route.c | 21 +++++++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)
--- 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;
};
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1762,6 +1762,7 @@ static struct rtable *__mkroute_output(c
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(c
}
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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