[PATCH 4.4 18/27] net: ipv4: Fix multipath selection with vrf

From: Greg Kroah-Hartman
Date: Fri Jan 13 2017 - 06:40:24 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>


[ Upstream commit 7a18c5b9fb31a999afc62b0e60978aa896fc89e9 ]

fib_select_path does not call fib_select_multipath if oif is set in the
flow struct. For VRF use cases oif is always set, so multipath route
selection is bypassed. Use the FLOWI_FLAG_SKIP_NH_OIF to skip the oif
check similar to what is done in fib_table_lookup.

Add saddr and proto to the flow struct for the fib lookup done by the
VRF driver to better match hash computation for a flow.

Fixes: 613d09b30f8b ("net: Use VRF device index for lookups on TX")
Signed-off-by: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/vrf.c | 2 ++
net/ipv4/fib_semantics.c | 9 +++++++--
2 files changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -301,7 +301,9 @@ static netdev_tx_t vrf_process_v4_outbou
.flowi4_tos = RT_TOS(ip4h->tos),
.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_L3MDEV_SRC |
FLOWI_FLAG_SKIP_NH_OIF,
+ .flowi4_proto = ip4h->protocol,
.daddr = ip4h->daddr,
+ .saddr = ip4h->saddr,
};

if (vrf_send_v4_prep(skb, &fl4, vrf_dev))
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1588,8 +1588,13 @@ void fib_select_multipath(struct fib_res
void fib_select_path(struct net *net, struct fib_result *res,
struct flowi4 *fl4, int mp_hash)
{
+ bool oif_check;
+
+ oif_check = (fl4->flowi4_oif == 0 ||
+ fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
+
#ifdef CONFIG_IP_ROUTE_MULTIPATH
- if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
+ if (res->fi->fib_nhs > 1 && oif_check) {
if (mp_hash < 0)
mp_hash = get_hash_from_flowi4(fl4) >> 1;

@@ -1599,7 +1604,7 @@ void fib_select_path(struct net *net, st
#endif
if (!res->prefixlen &&
res->table->tb_num_default > 1 &&
- res->type == RTN_UNICAST && !fl4->flowi4_oif)
+ res->type == RTN_UNICAST && oif_check)
fib_select_default(fl4, res);

if (!fl4->saddr)