openvswitch: Allow matching on conntrack label

Allow matching and setting the ct_label field. As with ct_mark, this is
populated by executing the CT action. The label field may be modified by
specifying a label and mask nested under the CT action. It is stored as
metadata attached to the connection. Label modification occurs after
lookup, and will only persist when the conntrack entry is committed by
providing the COMMIT flag to the CT action. Labels are currently fixed
to 128 bits in size.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 126 insertions, 2 deletions

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index e53dafccf21f..a0417fb33d1d 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -15,6 +15,7 @@
 #include <linux/openvswitch.h>
 #include <net/ip.h>
 #include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_labels.h>
 #include <net/netfilter/nf_conntrack_zones.h>
 #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
 
@@ -34,6 +35,12 @@ struct md_mark {
 	u32 mask;
 };
 
+/* Metadata label for masked write to conntrack label. */
+struct md_label {
+	struct ovs_key_ct_label value;
+	struct ovs_key_ct_label mask;
+};
+
 /* Conntrack action context for execution. */
 struct ovs_conntrack_info {
 	struct nf_conntrack_zone zone;
@@ -41,6 +48,7 @@ struct ovs_conntrack_info {
 	u32 flags;
 	u16 family;
 	struct md_mark mark;
+	struct md_label label;
 };
 
 static u16 key_to_nfproto(const struct sw_flow_key *key)
@@ -90,6 +98,24 @@ static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
 	return ct_state;
 }
 
+static void ovs_ct_get_label(const struct nf_conn *ct,
+			     struct ovs_key_ct_label *label)
+{
+	struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL;
+
+	if (cl) {
+		size_t len = cl->words * sizeof(long);
+
+		if (len > OVS_CT_LABEL_LEN)
+			len = OVS_CT_LABEL_LEN;
+		else if (len < OVS_CT_LABEL_LEN)
+			memset(label, 0, OVS_CT_LABEL_LEN);
+		memcpy(label, cl->bits, len);
+	} else {
+		memset(label, 0, OVS_CT_LABEL_LEN);
+	}
+}
+
 static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
 				const struct nf_conntrack_zone *zone,
 				const struct nf_conn *ct)
@@ -97,6 +123,7 @@ static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
 	key->ct.state = state;
 	key->ct.zone = zone->id;
 	key->ct.mark = ct ? ct->mark : 0;
+	ovs_ct_get_label(ct, &key->ct.label);
 }
 
 /* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has
@@ -140,6 +167,11 @@ int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
 	    nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark))
 		return -EMSGSIZE;
 
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABEL) &&
+	    nla_put(skb, OVS_KEY_ATTR_CT_LABEL, sizeof(key->ct.label),
+		    &key->ct.label))
+		return -EMSGSIZE;
+
 	return 0;
 }
 
@@ -168,6 +200,40 @@ static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key,
 	return 0;
 }
 
+static int ovs_ct_set_label(struct sk_buff *skb, struct sw_flow_key *key,
+			    const struct ovs_key_ct_label *label,
+			    const struct ovs_key_ct_label *mask)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn_labels *cl;
+	struct nf_conn *ct;
+	int err;
+
+	if (!IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS))
+		return -ENOTSUPP;
+
+	/* The connection could be invalid, in which case set_label is no-op.*/
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct)
+		return 0;
+
+	cl = nf_ct_labels_find(ct);
+	if (!cl) {
+		nf_ct_labels_ext_add(ct);
+		cl = nf_ct_labels_find(ct);
+	}
+	if (!cl || cl->words * sizeof(long) < OVS_CT_LABEL_LEN)
+		return -ENOSPC;
+
+	err = nf_connlabels_replace(ct, (u32 *)label, (u32 *)mask,
+				    OVS_CT_LABEL_LEN / sizeof(u32));
+	if (err)
+		return err;
+
+	ovs_ct_get_label(ct, &key->ct.label);
+	return 0;
+}
+
 static int handle_fragments(struct net *net, struct sw_flow_key *key,
 			    u16 zone, struct sk_buff *skb)
 {
@@ -327,6 +393,17 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 	return 0;
 }
 
+static bool label_nonzero(const struct ovs_key_ct_label *label)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(*label); i++)
+		if (label->ct_label[i])
+			return true;
+
+	return false;
+}
+
 int ovs_ct_execute(struct net *net, struct sk_buff *skb,
 		   struct sw_flow_key *key,
 		   const struct ovs_conntrack_info *info)
@@ -351,9 +428,15 @@ int ovs_ct_execute(struct net *net, struct sk_buff *skb,
 	if (err)
 		goto err;
 
-	if (info->mark.mask)
+	if (info->mark.mask) {
 		err = ovs_ct_set_mark(skb, key, info->mark.value,
 				      info->mark.mask);
+		if (err)
+			goto err;
+	}
+	if (label_nonzero(&info->label.mask))
+		err = ovs_ct_set_label(skb, key, &info->label.value,
+				       &info->label.mask);
 err:
 	skb_push(skb, nh_ofs);
 	return err;
@@ -366,6 +449,8 @@ static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
 				    .maxlen = sizeof(u16) },
 	[OVS_CT_ATTR_MARK]	= { .minlen = sizeof(struct md_mark),
 				    .maxlen = sizeof(struct md_mark) },
+	[OVS_CT_ATTR_LABEL]	= { .minlen = sizeof(struct md_label),
+				    .maxlen = sizeof(struct md_label) },
 };
 
 static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
@@ -409,6 +494,14 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
 			break;
 		}
 #endif
+#ifdef CONFIG_NF_CONNTRACK_LABELS
+		case OVS_CT_ATTR_LABEL: {
+			struct md_label *label = nla_data(a);
+
+			info->label = *label;
+			break;
+		}
+#endif
 		default:
 			OVS_NLERR(log, "Unknown conntrack attr (%d)",
 				  type);
@@ -424,7 +517,7 @@ static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
 	return 0;
 }
 
-bool ovs_ct_verify(enum ovs_key_attr attr)
+bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
 {
 	if (attr == OVS_KEY_ATTR_CT_STATE)
 		return true;
@@ -434,6 +527,12 @@ bool ovs_ct_verify(enum ovs_key_attr attr)
 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
 	    attr == OVS_KEY_ATTR_CT_MARK)
 		return true;
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
+	    attr == OVS_KEY_ATTR_CT_LABEL) {
+		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+
+		return ovs_net->xt_label;
+	}
 
 	return false;
 }
@@ -500,6 +599,10 @@ int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
 	    nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
 		    &ct_info->mark))
 		return -EMSGSIZE;
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
+	    nla_put(skb, OVS_CT_ATTR_LABEL, sizeof(ct_info->label),
+		    &ct_info->label))
+		return -EMSGSIZE;
 
 	nla_nest_end(skb, start);
 
@@ -513,3 +616,24 @@ void ovs_ct_free_action(const struct nlattr *a)
 	if (ct_info->ct)
 		nf_ct_put(ct_info->ct);
 }
+
+void ovs_ct_init(struct net *net)
+{
+	unsigned int n_bits = sizeof(struct ovs_key_ct_label) * BITS_PER_BYTE;
+	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+
+	if (nf_connlabels_get(net, n_bits)) {
+		ovs_net->xt_label = false;
+		OVS_NLERR(true, "Failed to set connlabel length");
+	} else {
+		ovs_net->xt_label = true;
+	}
+}
+
+void ovs_ct_exit(struct net *net)
+{
+	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+
+	if (ovs_net->xt_label)
+		nf_connlabels_put(net);
+}