[dpdk-dev] [PATCH 3/3] mlx4: do not expose broadcast address in MAC list

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

From: Didier Pallard <didier.pallard@6wind.com>

Use the last array entry to store the broadcast address and keep it hidden
by not reporting the entire array size.

This is done to prevent DPDK applications from attempting to modify or
remove it.

Signed-off-by: Didier Pallard <didier.pallard@6wind.com>
---
 drivers/net/mlx4/mlx4.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 9614471..af31573 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -3836,7 +3836,8 @@ mlx4_dev_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *info)
 		max = 65535;
 	info->max_rx_queues = max;
 	info->max_tx_queues = max;
-	info->max_mac_addrs = elemof(priv->mac);
+	/* Last array entry is reserved for broadcast. */
+	info->max_mac_addrs = (elemof(priv->mac) - 1);
 	info->rx_offload_capa =
 		(priv->hw_csum ?
 		 (DEV_RX_OFFLOAD_IPV4_CKSUM |
@@ -3969,11 +3970,8 @@ mlx4_mac_addr_remove(struct rte_eth_dev *dev, uint32_t index)
 	priv_lock(priv);
 	DEBUG("%p: removing MAC address from index %" PRIu32,
 	      (void *)dev, index);
-	if (index >= MLX4_MAX_MAC_ADDRESSES)
-		goto end;
-	/* Refuse to remove the broadcast address, this one is special. */
-	if (!memcmp(priv->mac[index].addr_bytes, "\xff\xff\xff\xff\xff\xff",
-		    ETHER_ADDR_LEN))
+	/* Last array entry is reserved for broadcast. */
+	if (index >= (elemof(priv->mac) - 1))
 		goto end;
 	priv_mac_addr_del(priv, index);
 end:
@@ -4002,11 +4000,8 @@ mlx4_mac_addr_add(struct rte_eth_dev *dev, struct ether_addr *mac_addr,
 	priv_lock(priv);
 	DEBUG("%p: adding MAC address at index %" PRIu32,
 	      (void *)dev, index);
-	if (index >= MLX4_MAX_MAC_ADDRESSES)
-		goto end;
-	/* Refuse to add the broadcast address, this one is special. */
-	if (!memcmp(mac_addr->addr_bytes, "\xff\xff\xff\xff\xff\xff",
-		    ETHER_ADDR_LEN))
+	/* Last array entry is reserved for broadcast. */
+	if (index >= (elemof(priv->mac) - 1))
 		goto end;
 	priv_mac_addr_add(priv, index,
 			  (const uint8_t (*)[ETHER_ADDR_LEN])
@@ -4943,7 +4938,7 @@ mlx4_pci_devinit(struct rte_pci_driver *pci_drv, struct rte_pci_device *pci_dev)
 		claim_zero(priv_mac_addr_add(priv, 0,
 					     (const uint8_t (*)[ETHER_ADDR_LEN])
 					     mac.addr_bytes));
-		claim_zero(priv_mac_addr_add(priv, 1,
+		claim_zero(priv_mac_addr_add(priv, (elemof(priv->mac) - 1),
 					     &(const uint8_t [ETHER_ADDR_LEN])
 					     { "\xff\xff\xff\xff\xff\xff" }));
 #ifndef NDEBUG
-- 
2.1.0