Re: [PATCH net-next 09/10] net/mlx4_en: Manage flow steering rules with ethtool

On 7/1/2012 7:00 PM, Ben Hutchings wrote:

quoted

+#define not_all_zeros_or_all_ones(field, type) \

quoted

+	(field && (type)~field)
+
+static int mlx4_en_validate_flow(struct net_device *dev,
+				 struct ethtool_rxnfc *cmd)
+{
+	struct ethtool_usrip4_spec *l3_mask;
+	struct ethtool_tcpip4_spec *l4_mask;
+	struct ethhdr *eth_mask;
+	u64 full_mac = ~0ull;
+	u64 zero_mac = 0;
+
+	if (cmd->fs.location >= MAX_NUM_OF_FS_RULES)
+		return -EINVAL;
+
+	switch (cmd->fs.flow_type & ~FLOW_EXT) {
+	case TCP_V4_FLOW:
+	case UDP_V4_FLOW:
+		if (cmd->fs.h_u.tcp_ip4_spec.tos)
+			return -EOPNOTSUPP;

I suspect that your filter ignores TOS, rather than only matching TOS ==
0, so you should actually be checking the corresponding field in the
mask (fs.m_u). [...]

OK, thanks for pointing this over, will fix.

quoted

+		break;
+	case IP_USER_FLOW:
+		l3_mask = &cmd->fs.m_u.usr_ip4_spec;
+		if (cmd->fs.h_u.usr_ip4_spec.l4_4_bytes ||
+		    cmd->fs.h_u.usr_ip4_spec.tos ||

I think this should be checking l4_4_bytes and tos in the mask.

OK

quoted

quoted

+		    cmd->fs.h_u.usr_ip4_spec.proto ||
+		    cmd->fs.h_u.usr_ip4_spec.ip_ver != ETH_RX_NFC_IP4 ||
+		    (!cmd->fs.h_u.usr_ip4_spec.ip4src &&
+		     !cmd->fs.h_u.usr_ip4_spec.ip4dst) ||
+		    not_all_zeros_or_all_ones(l3_mask->ip4src, __be32) ||
+		    not_all_zeros_or_all_ones(l3_mask->ip4dst, __be32))
+			return -EOPNOTSUPP;
+		break;
+	case ETHER_FLOW:
+		eth_mask = &cmd->fs.m_u.ether_spec;
+		if (memcmp(eth_mask->h_source, &zero_mac, ETH_ALEN))
+			return -EOPNOTSUPP;
+		if (!memcmp(eth_mask->h_dest, &zero_mac, ETH_ALEN))
+			return -EOPNOTSUPP;

But in the next statement you test whether eth_mask->h_dest is either
all-zeroes or all-ones.  Is all-zeroes valid or not?  I suspect you
actually intend to reject the case where both h_dest and h_proto are masked out.

indeed, this code section can be better written, will fix for V1

quoted

quoted

+		if (not_all_zeros_or_all_ones(eth_mask->h_proto, __be16) ||
+		    (memcmp(eth_mask->h_dest, &zero_mac, ETH_ALEN) &&
+		     memcmp(eth_mask->h_dest, &full_mac, ETH_ALEN)))
+			return -EOPNOTSUPP;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if ((cmd->fs.flow_type & FLOW_EXT)) {
+		if (cmd->fs.m_ext.vlan_etype ||
+		    not_all_zeros_or_all_ones(cmd->fs.m_ext.vlan_tci,
+					       __be16)) {
+			return -EOPNOTSUPP;
+		}
+	}
+
+	return 0;
+}