netfilter: nftables_offload: set address type in control dissector

This patch adds nft_flow_rule_set_addr_type() to set the address type
from the nft_payload expression accordingly.

If the address type is not set in the control dissector then a rule that
matches either on source or destination IP address does not work.

After this patch, nft hardware offload generates the flow dissector
configuration as tc-flower does to match on an IP address.

This patch has been also tested functionally to make sure packets are
filtered out by the NIC.

This is also getting the code aligned with the existing netfilter flow
offload infrastructure which is also setting the control dissector.

Fixes: c9626a2c ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables_offload.h

@@ -37,6 +37,7 @@ void nft_offload_update_dependency(struct nft_offload_ctx *ctx,
 
 struct nft_flow_key {
 	struct flow_dissector_key_basic			basic;
+	struct flow_dissector_key_control		control;
 	union {
 		struct flow_dissector_key_ipv4_addrs	ipv4;
 		struct flow_dissector_key_ipv6_addrs	ipv6;
@@ -62,6 +63,9 @@ struct nft_flow_rule {
 
 #define NFT_OFFLOAD_F_ACTION	(1 << 0)
 
+void nft_flow_rule_set_addr_type(struct nft_flow_rule *flow,
+				 enum flow_dissector_key_id addr_type);
+
 struct nft_rule;
 struct nft_flow_rule *nft_flow_rule_create(struct net *net, const struct nft_rule *rule);
 void nft_flow_rule_destroy(struct nft_flow_rule *flow);

net/netfilter/nf_tables_offload.c

@@ -28,6 +28,23 @@ static struct nft_flow_rule *nft_flow_rule_alloc(int num_actions)
 	return flow;
 }
 
+void nft_flow_rule_set_addr_type(struct nft_flow_rule *flow,
+				 enum flow_dissector_key_id addr_type)
+{
+	struct nft_flow_match *match = &flow->match;
+	struct nft_flow_key *mask = &match->mask;
+	struct nft_flow_key *key = &match->key;
+
+	if (match->dissector.used_keys & BIT(FLOW_DISSECTOR_KEY_CONTROL))
+		return;
+
+	key->control.addr_type = addr_type;
+	mask->control.addr_type = 0xffff;
+	match->dissector.used_keys |= BIT(FLOW_DISSECTOR_KEY_CONTROL);
+	match->dissector.offset[FLOW_DISSECTOR_KEY_CONTROL] =
+		offsetof(struct nft_flow_key, control);
+}
+
 struct nft_flow_rule *nft_flow_rule_create(struct net *net,
 					   const struct nft_rule *rule)
 {

net/netfilter/nft_payload.c

@@ -244,6 +244,7 @@ static int nft_payload_offload_ip(struct nft_offload_ctx *ctx,
 
 		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4, src,
 				  sizeof(struct in_addr), reg);
+		nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV4_ADDRS);
 		break;
 	case offsetof(struct iphdr, daddr):
 		if (priv->len != sizeof(struct in_addr))
@@ -251,6 +252,7 @@ static int nft_payload_offload_ip(struct nft_offload_ctx *ctx,
 
 		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4, dst,
 				  sizeof(struct in_addr), reg);
+		nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV4_ADDRS);
 		break;
 	case offsetof(struct iphdr, protocol):
 		if (priv->len != sizeof(__u8))
@@ -280,6 +282,7 @@ static int nft_payload_offload_ip6(struct nft_offload_ctx *ctx,
 
 		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6, src,
 				  sizeof(struct in6_addr), reg);
+		nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV6_ADDRS);
 		break;
 	case offsetof(struct ipv6hdr, daddr):
 		if (priv->len != sizeof(struct in6_addr))
@@ -287,6 +290,7 @@ static int nft_payload_offload_ip6(struct nft_offload_ctx *ctx,
 
 		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6, dst,
 				  sizeof(struct in6_addr), reg);
+		nft_flow_rule_set_addr_type(flow, FLOW_DISSECTOR_KEY_IPV6_ADDRS);
 		break;
 	case offsetof(struct ipv6hdr, nexthdr):
 		if (priv->len != sizeof(__u8))