Thread (21 messages) flat view 21 messages, 2 authors, 2018-10-12
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[PATCH net-next 08/19] mlxsw: spectrum: Seed LAG hash function

From: Ido Schimmel <hidden>
Date: 2018-10-11 15:14:06
Subsystem: mellanox ethernet switch drivers, networking drivers, the rest · Maintainers: Ido Schimmel, Petr Machata, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Currently, the seed of the LAG hash function is always set to 0, which
means it is identical across all switches. Instead, use a random number.

This is especially important now that VxLAN is supported, as the LAG
hash function is used to calculate the UDP source port of the
encapsulated packet.

Signed-off-by: Ido Schimmel <redacted>
Reviewed-by: Petr Machata <redacted>
---
 drivers/net/ethernet/mellanox/mlxsw/reg.h      | 9 ++++++++-
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 5 ++++-
 2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/reg.h b/drivers/net/ethernet/mellanox/mlxsw/reg.h
index a0441f3d4284..4988d24a628c 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/reg.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/reg.h
@@ -1321,12 +1321,19 @@ MLXSW_ITEM32(reg, slcr, type, 0x00, 0, 4);
  */
 MLXSW_ITEM32(reg, slcr, lag_hash, 0x04, 0, 20);
 
-static inline void mlxsw_reg_slcr_pack(char *payload, u16 lag_hash)
+/* reg_slcr_seed
+ * LAG seed value. The seed is the same for all ports.
+ * Access: RW
+ */
+MLXSW_ITEM32(reg, slcr, seed, 0x08, 0, 32);
+
+static inline void mlxsw_reg_slcr_pack(char *payload, u16 lag_hash, u32 seed)
 {
 	MLXSW_REG_ZERO(slcr, payload);
 	mlxsw_reg_slcr_pp_set(payload, MLXSW_REG_SLCR_PP_GLOBAL);
 	mlxsw_reg_slcr_type_set(payload, MLXSW_REG_SLCR_TYPE_CRC);
 	mlxsw_reg_slcr_lag_hash_set(payload, lag_hash);
+	mlxsw_reg_slcr_seed_set(payload, seed);
 }
 
 /* SLCOR - Switch LAG Collector Register
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 2b14fd0dcc42..d42980df57b7 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -21,6 +21,7 @@
 #include <linux/dcbnl.h>
 #include <linux/inetdevice.h>
 #include <linux/netlink.h>
+#include <linux/random.h>
 #include <net/switchdev.h>
 #include <net/pkt_cls.h>
 #include <net/tc_act/tc_mirred.h>
@@ -3666,8 +3667,10 @@ static void mlxsw_sp_traps_fini(struct mlxsw_sp *mlxsw_sp)
 static int mlxsw_sp_lag_init(struct mlxsw_sp *mlxsw_sp)
 {
 	char slcr_pl[MLXSW_REG_SLCR_LEN];
+	u32 seed;
 	int err;
 
+	get_random_bytes(&seed, sizeof(seed));
 	mlxsw_reg_slcr_pack(slcr_pl, MLXSW_REG_SLCR_LAG_HASH_SMAC |
 				     MLXSW_REG_SLCR_LAG_HASH_DMAC |
 				     MLXSW_REG_SLCR_LAG_HASH_ETHERTYPE |
@@ -3676,7 +3679,7 @@ static int mlxsw_sp_lag_init(struct mlxsw_sp *mlxsw_sp)
 				     MLXSW_REG_SLCR_LAG_HASH_DIP |
 				     MLXSW_REG_SLCR_LAG_HASH_SPORT |
 				     MLXSW_REG_SLCR_LAG_HASH_DPORT |
-				     MLXSW_REG_SLCR_LAG_HASH_IPPROTO);
+				     MLXSW_REG_SLCR_LAG_HASH_IPPROTO, seed);
 	err = mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(slcr), slcr_pl);
 	if (err)
 		return err;
-- 
2.17.1
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