net: openvswitch: Support masked set actions.

OVS userspace already probes the openvswitch kernel module for
OVS_ACTION_ATTR_SET_MASKED support.  This patch adds the kernel module
implementation of masked set actions.

The existing set action sets many fields at once.  When only a subset
of the IP header fields, for example, should be modified, all the IP
fields need to be exact matched so that the other field values can be
copied to the set action.  A masked set action allows modification of
an arbitrary subset of the supported header bits without requiring the
rest to be matched.

Masked set action is now supported for all writeable key types, except
for the tunnel key.  The set tunnel action is an exception as any
input tunnel info is cleared before action processing starts, so there
is no tunnel info to mask.

The kernel module converts all (non-tunnel) set actions to masked set
actions.  This makes action processing more uniform, and results in
less branching and duplicating the action processing code.  When
returning actions to userspace, the fully masked set actions are
converted back to normal set actions.  We use a kernel internal action
code to be able to tell the userspace provided and converted masked
set actions apart.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/openvswitch.h

@@ -599,6 +599,12 @@ struct ovs_action_hash {
  * @OVS_ACTION_ATTR_SET: Replaces the contents of an existing header.  The
  * single nested %OVS_KEY_ATTR_* attribute specifies a header to modify and its
  * value.
+ * @OVS_ACTION_ATTR_SET_MASKED: Replaces the contents of an existing header.  A
+ * nested %OVS_KEY_ATTR_* attribute specifies a header to modify, its value,
+ * and a mask.  For every bit set in the mask, the corresponding bit value
+ * is copied from the value to the packet header field, rest of the bits are
+ * left unchanged.  The non-masked value bits must be passed in as zeroes.
+ * Masking is not supported for the %OVS_KEY_ATTR_TUNNEL attribute.
  * @OVS_ACTION_ATTR_PUSH_VLAN: Push a new outermost 802.1Q header onto the
  * packet.
  * @OVS_ACTION_ATTR_POP_VLAN: Pop the outermost 802.1Q header off the packet.
@@ -617,6 +623,9 @@ struct ovs_action_hash {
  * Only a single header can be set with a single %OVS_ACTION_ATTR_SET.  Not all
  * fields within a header are modifiable, e.g. the IPv4 protocol and fragment
  * type may not be changed.
+ *
+ * @OVS_ACTION_ATTR_SET_TO_MASKED: Kernel internal masked set action translated
+ * from the @OVS_ACTION_ATTR_SET.
  */
 
 enum ovs_action_attr {
@@ -631,8 +640,19 @@ enum ovs_action_attr {
 	OVS_ACTION_ATTR_HASH,	      /* struct ovs_action_hash. */
 	OVS_ACTION_ATTR_PUSH_MPLS,    /* struct ovs_action_push_mpls. */
 	OVS_ACTION_ATTR_POP_MPLS,     /* __be16 ethertype. */
+	OVS_ACTION_ATTR_SET_MASKED,   /* One nested OVS_KEY_ATTR_* including
+				       * data immediately followed by a mask.
+				       * The data must be zero for the unmasked
+				       * bits. */
+
+	__OVS_ACTION_ATTR_MAX,	      /* Nothing past this will be accepted
+				       * from userspace. */
 
-	__OVS_ACTION_ATTR_MAX
+#ifdef __KERNEL__
+	OVS_ACTION_ATTR_SET_TO_MASKED, /* Kernel module internal masked
+					* set action converted from
+					* OVS_ACTION_ATTR_SET. */
+#endif
 };
 
 #define OVS_ACTION_ATTR_MAX (__OVS_ACTION_ATTR_MAX - 1)

net/openvswitch/flow_netlink.c

@@ -1695,16 +1695,6 @@ static int validate_and_copy_sample(const struct nlattr *attr,
 	return 0;
 }
 
-static int validate_tp_port(const struct sw_flow_key *flow_key,
-			    __be16 eth_type)
-{
-	if ((eth_type == htons(ETH_P_IP) || eth_type == htons(ETH_P_IPV6)) &&
-	    (flow_key->tp.src || flow_key->tp.dst))
-		return 0;
-
-	return -EINVAL;
-}
-
 void ovs_match_init(struct sw_flow_match *match,
 		    struct sw_flow_key *key,
 		    struct sw_flow_mask *mask)
@@ -1805,23 +1795,45 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
 	return err;
 }
 
+/* Return false if there are any non-masked bits set.
+ * Mask follows data immediately, before any netlink padding.
+ */
+static bool validate_masked(u8 *data, int len)
+{
+	u8 *mask = data + len;
+
+	while (len--)
+		if (*data++ & ~*mask++)
+			return false;
+
+	return true;
+}
+
 static int validate_set(const struct nlattr *a,
 			const struct sw_flow_key *flow_key,
 			struct sw_flow_actions **sfa,
-			bool *set_tun, __be16 eth_type, bool log)
+			bool *skip_copy, __be16 eth_type, bool masked, bool log)
 {
 	const struct nlattr *ovs_key = nla_data(a);
 	int key_type = nla_type(ovs_key);
+	size_t key_len;
 
 	/* There can be only one key in a action */
 	if (nla_total_size(nla_len(ovs_key)) != nla_len(a))
 		return -EINVAL;
 
+	key_len = nla_len(ovs_key);
+	if (masked)
+		key_len /= 2;
+
 	if (key_type > OVS_KEY_ATTR_MAX ||
-	    (ovs_key_lens[key_type].len != nla_len(ovs_key) &&
+	    (ovs_key_lens[key_type].len != key_len &&
 	     ovs_key_lens[key_type].len != OVS_ATTR_NESTED))
 		return -EINVAL;
 
+	if (masked && !validate_masked(nla_data(ovs_key), key_len))
+		return -EINVAL;
+
 	switch (key_type) {
 	const struct ovs_key_ipv4 *ipv4_key;
 	const struct ovs_key_ipv6 *ipv6_key;
@@ -1836,7 +1848,10 @@ static int validate_set(const struct nlattr *a,
 		if (eth_p_mpls(eth_type))
 			return -EINVAL;
 
-		*set_tun = true;
+		if (masked)
+			return -EINVAL; /* Masked tunnel set not supported. */
+
+		*skip_copy = true;
 		err = validate_and_copy_set_tun(a, sfa, log);
 		if (err)
 			return err;
@@ -1846,48 +1861,66 @@ static int validate_set(const struct nlattr *a,
 		if (eth_type != htons(ETH_P_IP))
 			return -EINVAL;
 
-		if (!flow_key->ip.proto)
-			return -EINVAL;
-
 		ipv4_key = nla_data(ovs_key);
-		if (ipv4_key->ipv4_proto != flow_key->ip.proto)
-			return -EINVAL;
 
-		if (ipv4_key->ipv4_frag != flow_key->ip.frag)
-			return -EINVAL;
+		if (masked) {
+			const struct ovs_key_ipv4 *mask = ipv4_key + 1;
 
+			/* Non-writeable fields. */
+			if (mask->ipv4_proto || mask->ipv4_frag)
+				return -EINVAL;
+		} else {
+			if (ipv4_key->ipv4_proto != flow_key->ip.proto)
+				return -EINVAL;
+
+			if (ipv4_key->ipv4_frag != flow_key->ip.frag)
+				return -EINVAL;
+		}
 		break;
 
 	case OVS_KEY_ATTR_IPV6:
 		if (eth_type != htons(ETH_P_IPV6))
 			return -EINVAL;
 
-		if (!flow_key->ip.proto)
-			return -EINVAL;
-
 		ipv6_key = nla_data(ovs_key);
-		if (ipv6_key->ipv6_proto != flow_key->ip.proto)
-			return -EINVAL;
 
-		if (ipv6_key->ipv6_frag != flow_key->ip.frag)
-			return -EINVAL;
+		if (masked) {
+			const struct ovs_key_ipv6 *mask = ipv6_key + 1;
+
+			/* Non-writeable fields. */
+			if (mask->ipv6_proto || mask->ipv6_frag)
+				return -EINVAL;
+
+			/* Invalid bits in the flow label mask? */
+			if (ntohl(mask->ipv6_label) & 0xFFF00000)
+				return -EINVAL;
+		} else {
+			if (ipv6_key->ipv6_proto != flow_key->ip.proto)
+				return -EINVAL;
 
+			if (ipv6_key->ipv6_frag != flow_key->ip.frag)
+				return -EINVAL;
+		}
 		if (ntohl(ipv6_key->ipv6_label) & 0xFFF00000)
 			return -EINVAL;
 
 		break;
 
 	case OVS_KEY_ATTR_TCP:
-		if (flow_key->ip.proto != IPPROTO_TCP)
+		if ((eth_type != htons(ETH_P_IP) &&
+		     eth_type != htons(ETH_P_IPV6)) ||
+		    flow_key->ip.proto != IPPROTO_TCP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		break;
 
 	case OVS_KEY_ATTR_UDP:
-		if (flow_key->ip.proto != IPPROTO_UDP)
+		if ((eth_type != htons(ETH_P_IP) &&
+		     eth_type != htons(ETH_P_IPV6)) ||
+		    flow_key->ip.proto != IPPROTO_UDP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		break;
 
 	case OVS_KEY_ATTR_MPLS:
 		if (!eth_p_mpls(eth_type))
@@ -1895,15 +1928,45 @@ static int validate_set(const struct nlattr *a,
 		break;
 
 	case OVS_KEY_ATTR_SCTP:
-		if (flow_key->ip.proto != IPPROTO_SCTP)
+		if ((eth_type != htons(ETH_P_IP) &&
+		     eth_type != htons(ETH_P_IPV6)) ||
+		    flow_key->ip.proto != IPPROTO_SCTP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		break;
 
 	default:
 		return -EINVAL;
 	}
 
+	/* Convert non-masked non-tunnel set actions to masked set actions. */
+	if (!masked && key_type != OVS_KEY_ATTR_TUNNEL) {
+		int start, len = key_len * 2;
+		struct nlattr *at;
+
+		*skip_copy = true;
+
+		start = add_nested_action_start(sfa,
+						OVS_ACTION_ATTR_SET_TO_MASKED,
+						log);
+		if (start < 0)
+			return start;
+
+		at = __add_action(sfa, key_type, NULL, len, log);
+		if (IS_ERR(at))
+			return PTR_ERR(at);
+
+		memcpy(nla_data(at), nla_data(ovs_key), key_len); /* Key. */
+		memset(nla_data(at) + key_len, 0xff, key_len);    /* Mask. */
+		/* Clear non-writeable bits from otherwise writeable fields. */
+		if (key_type == OVS_KEY_ATTR_IPV6) {
+			struct ovs_key_ipv6 *mask = nla_data(at) + key_len;
+
+			mask->ipv6_label &= htonl(0x000FFFFF);
+		}
+		add_nested_action_end(*sfa, start);
+	}
+
 	return 0;
 }
 
@@ -1965,6 +2028,7 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 			[OVS_ACTION_ATTR_PUSH_VLAN] = sizeof(struct ovs_action_push_vlan),
 			[OVS_ACTION_ATTR_POP_VLAN] = 0,
 			[OVS_ACTION_ATTR_SET] = (u32)-1,
+			[OVS_ACTION_ATTR_SET_MASKED] = (u32)-1,
 			[OVS_ACTION_ATTR_SAMPLE] = (u32)-1,
 			[OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash)
 		};
@@ -2060,7 +2124,14 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 
 		case OVS_ACTION_ATTR_SET:
 			err = validate_set(a, key, sfa,
-					   &skip_copy, eth_type, log);
+					   &skip_copy, eth_type, false, log);
+			if (err)
+				return err;
+			break;
+
+		case OVS_ACTION_ATTR_SET_MASKED:
+			err = validate_set(a, key, sfa,
+					   &skip_copy, eth_type, true, log);
 			if (err)
 				return err;
 			break;
@@ -2090,6 +2161,7 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 	return 0;
 }
 
+/* 'key' must be the masked key. */
 int ovs_nla_copy_actions(const struct nlattr *attr,
 			 const struct sw_flow_key *key,
 			 struct sw_flow_actions **sfa, bool log)
@@ -2177,6 +2249,21 @@ static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
 	return 0;
 }
 
+static int masked_set_action_to_set_action_attr(const struct nlattr *a,
+						struct sk_buff *skb)
+{
+	const struct nlattr *ovs_key = nla_data(a);
+	size_t key_len = nla_len(ovs_key) / 2;
+
+	/* Revert the conversion we did from a non-masked set action to
+	 * masked set action.
+	 */
+	if (nla_put(skb, OVS_ACTION_ATTR_SET, nla_len(a) - key_len, ovs_key))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
 int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
 {
 	const struct nlattr *a;
@@ -2192,6 +2279,12 @@ int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
 				return err;
 			break;
 
+		case OVS_ACTION_ATTR_SET_TO_MASKED:
+			err = masked_set_action_to_set_action_attr(a, skb);
+			if (err)
+				return err;
+			break;
+
 		case OVS_ACTION_ATTR_SAMPLE:
 			err = sample_action_to_attr(a, skb);
 			if (err)