linux-kernel - [PATCH net] openvswitch: Fix mask generation for IPv6 labels.

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Message-Id: <1416336857-61405-1-git-send-email-joestringer@nicira.com>
Date:	Tue, 18 Nov 2014 10:54:17 -0800
From:	Joe Stringer <joestringer@...ira.com>
To:	netdev@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, pshelar@...ira.com,
	dev@...nvswitch.org
Subject: [PATCH net] openvswitch: Fix mask generation for IPv6 labels.

When userspace doesn't provide a mask, OVS datapath generates a fully
unwildcarded mask for the flow. This is done by taking a copy of the
flow key, then iterating across its attributes, setting all values to
0xff. This works for most attributes, as the length of the netlink
attribute typically matches the length of the value. However, IPv6
labels only use the lower 20 bits of the field. This patch makes a
special case to handle this.

This fixes the following error seen when installing IPv6 flows without a mask:

openvswitch: netlink: Invalid IPv6 flow label value (value=ffffffff, max=fffff)

Signed-off-by: Joe Stringer <joestringer@...ira.com>
---
 net/openvswitch/flow_netlink.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index fa4ec2e..7a5b28f 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -825,7 +825,7 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match, u64 attrs,
 	return 0;
 }
 
-static void nlattr_set(struct nlattr *attr, u8 val, bool is_attr_mask_key)
+static void mask_set_nlattr(struct nlattr *attr)
 {
 	struct nlattr *nla;
 	int rem;
@@ -835,16 +835,18 @@ static void nlattr_set(struct nlattr *attr, u8 val, bool is_attr_mask_key)
 		/* We assume that ovs_key_lens[type] == -1 means that type is a
 		 * nested attribute
 		 */
-		if (is_attr_mask_key && ovs_key_lens[nla_type(nla)] == -1)
-			nlattr_set(nla, val, false);
+		if (ovs_key_lens[nla_type(nla)] == -1)
+			nla_for_each_nested(nla, attr, rem)
+				memset(nla_data(nla), 0xff, nla_len(nla));
 		else
-			memset(nla_data(nla), val, nla_len(nla));
-	}
-}
+			memset(nla_data(nla), 0xff, nla_len(nla));
 
-static void mask_set_nlattr(struct nlattr *attr, u8 val)
-{
-	nlattr_set(attr, val, true);
+		if (nla_type(nla) == OVS_KEY_ATTR_IPV6) {
+			struct ovs_key_ipv6 *ipv6_key = nla_data(nla);
+
+			ipv6_key->ipv6_label &= htonl(0x000FFFFF);
+		}
+	}
 }
 
 /**
@@ -926,7 +928,7 @@ int ovs_nla_get_match(struct sw_flow_match *match,
 		if (!newmask)
 			return -ENOMEM;
 
-		mask_set_nlattr(newmask, 0xff);
+		mask_set_nlattr(newmask);
 
 		/* The userspace does not send tunnel attributes that are 0,
 		 * but we should not wildcard them nonetheless.
-- 
1.7.10.4

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