[PATCH net-next 0/2] mlxsw: Small routing improvements

[PATCH net-next 0/2] mlxsw: Small routing improvements

[Ido Schimmel]

Patch #1 switches the driver to use a unique and stable ECMP/LAG seed.
This allows for consistent behavior across reboots and avoids hash
polarization at the same time.

Patch #2 relaxes the FIB rule validation in the driver to allow the
installation of rules that direct locally generated traffic (iif=lo).
This does not result in a discrepancy between both data paths because
packets received by the device would never match such rules.

Ido Schimmel (2):
  mlxsw: spectrum: Use a stable ECMP/LAG seed
  mlxsw: spectrum_router: Relax FIB rule validation

 drivers/net/ethernet/mellanox/mlxsw/spectrum.c        | 4 ++--
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 8 ++++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

-- 
2.20.1

[PATCH net-next 1/2] mlxsw: spectrum: Use a stable ECMP/LAG seed

[Ido Schimmel]

In order to get a consistent behavior of traffic flows across reboots /
module unload, we need to use the same ECMP/LAG seed.

Calculate the seed by hashing the base MAC of the device. This results
in a seed that is both unique (to avoid polarization) and consistent.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c        | 4 ++--
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index fc325f1213fb..a1c2b117a2b3 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -21,7 +21,7 @@
 #include <linux/dcbnl.h>
 #include <linux/inetdevice.h>
 #include <linux/netlink.h>
-#include <linux/random.h>
+#include <linux/jhash.h>
 #include <net/switchdev.h>
 #include <net/pkt_cls.h>
 #include <net/tc_act/tc_mirred.h>
@@ -4227,7 +4227,7 @@ static int mlxsw_sp_lag_init(struct mlxsw_sp *mlxsw_sp)
 	u32 seed;
 	int err;
 
-	get_random_bytes(&seed, sizeof(seed));
+	seed = jhash(mlxsw_sp->base_mac, sizeof(mlxsw_sp->base_mac), 0);
 	mlxsw_reg_slcr_pack(slcr_pl, MLXSW_REG_SLCR_LAG_HASH_SMAC |
 				     MLXSW_REG_SLCR_LAG_HASH_DMAC |
 				     MLXSW_REG_SLCR_LAG_HASH_ETHERTYPE |
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 64498c9f55ab..6c73400b1508 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -13,9 +13,9 @@
 #include <linux/socket.h>
 #include <linux/route.h>
 #include <linux/gcd.h>
-#include <linux/random.h>
 #include <linux/if_macvlan.h>
 #include <linux/refcount.h>
+#include <linux/jhash.h>
 #include <net/netevent.h>
 #include <net/neighbour.h>
 #include <net/arp.h>
@@ -7831,7 +7831,7 @@ static int mlxsw_sp_mp_hash_init(struct mlxsw_sp *mlxsw_sp)
 	char recr2_pl[MLXSW_REG_RECR2_LEN];
 	u32 seed;
 
-	get_random_bytes(&seed, sizeof(seed));
+	seed = jhash(mlxsw_sp->base_mac, sizeof(mlxsw_sp->base_mac), 0);
 	mlxsw_reg_recr2_pack(recr2_pl, seed);
 	mlxsw_sp_mp4_hash_init(recr2_pl);
 	mlxsw_sp_mp6_hash_init(recr2_pl);
-- 
2.20.1

[PATCH net-next 2/2] mlxsw: spectrum_router: Relax FIB rule validation

[Ido Schimmel]

Currently, mlxsw does not support policy-based routing (PBR) and
therefore forbids the installation of non-default FIB rules except for
the l3mdev rule which is used for VRFs.

Relax the check to allow the installation of FIB rules that would never
match packets received by the device. Specifically, if the iif is that
of the loopback netdev. This is useful for users that need to redirect
locally generated packets based on FIB rules.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Tested-by: Alexander Petrovskiy <alexpe@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 6c73400b1508..8f31c2ddc538 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -6050,6 +6050,10 @@ static int mlxsw_sp_router_fib_rule_event(unsigned long event,
 	fr_info = container_of(info, struct fib_rule_notifier_info, info);
 	rule = fr_info->rule;
 
+	/* Rule only affects locally generated traffic */
+	if (rule->iifindex == info->net->loopback_dev->ifindex)
+		return 0;
+
 	switch (info->family) {
 	case AF_INET:
 		if (!fib4_rule_default(rule) && !rule->l3mdev)
-- 
2.20.1

Re: [PATCH net-next 0/2] mlxsw: Small routing improvements

[David Miller]

From: Ido Schimmel <idosch@mellanox.com>
Date: Sun, 21 Apr 2019 07:18:33 +0000

> Patch #1 switches the driver to use a unique and stable ECMP/LAG seed.
> This allows for consistent behavior across reboots and avoids hash
> polarization at the same time.
> 
> Patch #2 relaxes the FIB rule validation in the driver to allow the
> installation of rules that direct locally generated traffic (iif=lo).
> This does not result in a discrepancy between both data paths because
> packets received by the device would never match such rules.

Series applied, thanks.