Patch "net: ipv4: Fix multipath selection with vrf" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

net: ipv4: Fix multipath selection with vrf

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-ipv4-fix-multipath-selection-with-vrf.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Ahern <[email protected]>
Date: Tue, 10 Jan 2017 14:37:35 -0800
Subject: net: ipv4: Fix multipath selection with vrf

From: David Ahern <[email protected]>

[ 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.

---
 drivers/net/vrf.c        |    2 ++
 net/ipv4/fib_semantics.c |    9 +++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

@@ -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))

@@ -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)

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/net-vrf-drop-conntrack-data-after-pass-through-vrf-device-on-tx.patch queue-4.4/net-ipv4-fix-multipath-selection-with-vrf.patch queue-4.4/net-vrf-do-not-allow-table-id-0.patch