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authorJulian Anastasov <ja@ssi.bg>2012-10-08 13:41:19 +0200
committerDavid S. Miller <davem@davemloft.net>2012-10-08 23:42:36 +0200
commitc92b96553a80c1dbe2ebe128bbe37c8f98f148bf (patch)
tree2c08aaddff418e7be5c0674aeb9e4b94ec538179
parentipv4: introduce rt_uses_gateway (diff)
downloadlinux-c92b96553a80c1dbe2ebe128bbe37c8f98f148bf.tar.xz
linux-c92b96553a80c1dbe2ebe128bbe37c8f98f148bf.zip
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 <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/flow.h1
-rw-r--r--net/ipv4/route.c21
2 files changed, 18 insertions, 4 deletions
diff --git a/include/net/flow.h b/include/net/flow.h
index e1dd5082ec7e..628e11b98c58 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 3a116cb0991a..1a0da8dc8180 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);