flow_offload: add flow_rule and flow_match structures and use them

This patch wraps the dissector key and mask - that flower uses to
represent the matching side - around the flow_match structure.

To avoid a follow up patch that would edit the same LoCs in the drivers,
this patch also wraps this new flow match structure around the flow rule
object. This new structure will also contain the flow actions in follow
up patches.

This introduces two new interfaces:

	bool flow_rule_match_key(rule, dissector_id)

that returns true if a given matching key is set on, and:

	flow_rule_match_XYZ(rule, &match);

To fetch the matching side XYZ into the match container structure, to
retrieve the key and the mask with one single call.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 178 insertions, 14 deletions

diff --git a/net/core/Makefile b/net/core/Makefile
index fccd31e0e7f7..f97d6254e564 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -11,7 +11,7 @@ obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
 obj-y		     += dev.o ethtool.o dev_addr_lists.o dst.o netevent.o \
 			neighbour.o rtnetlink.o utils.o link_watch.o filter.o \
 			sock_diag.o dev_ioctl.o tso.o sock_reuseport.o \
-			fib_notifier.o xdp.o
+			fib_notifier.o xdp.o flow_offload.o
 
 obj-y += net-sysfs.o
 obj-$(CONFIG_PAGE_POOL) += page_pool.o
diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c
new file mode 100644
index 000000000000..2fbf6903d2f6
--- /dev/null
+++ b/net/core/flow_offload.c
@@ -0,0 +1,143 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <net/flow_offload.h>
+
+struct flow_rule *flow_rule_alloc(void)
+{
+	return kzalloc(sizeof(struct flow_rule), GFP_KERNEL);
+}
+EXPORT_SYMBOL(flow_rule_alloc);
+
+#define FLOW_DISSECTOR_MATCH(__rule, __type, __out)				\
+	const struct flow_match *__m = &(__rule)->match;			\
+	struct flow_dissector *__d = (__m)->dissector;				\
+										\
+	(__out)->key = skb_flow_dissector_target(__d, __type, (__m)->key);	\
+	(__out)->mask = skb_flow_dissector_target(__d, __type, (__m)->mask);	\
+
+void flow_rule_match_basic(const struct flow_rule *rule,
+			   struct flow_match_basic *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_BASIC, out);
+}
+EXPORT_SYMBOL(flow_rule_match_basic);
+
+void flow_rule_match_control(const struct flow_rule *rule,
+			     struct flow_match_control *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_CONTROL, out);
+}
+EXPORT_SYMBOL(flow_rule_match_control);
+
+void flow_rule_match_eth_addrs(const struct flow_rule *rule,
+			       struct flow_match_eth_addrs *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ETH_ADDRS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_eth_addrs);
+
+void flow_rule_match_vlan(const struct flow_rule *rule,
+			  struct flow_match_vlan *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_VLAN, out);
+}
+EXPORT_SYMBOL(flow_rule_match_vlan);
+
+void flow_rule_match_ipv4_addrs(const struct flow_rule *rule,
+				struct flow_match_ipv4_addrs *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IPV4_ADDRS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_ipv4_addrs);
+
+void flow_rule_match_ipv6_addrs(const struct flow_rule *rule,
+				struct flow_match_ipv6_addrs *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IPV6_ADDRS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_ipv6_addrs);
+
+void flow_rule_match_ip(const struct flow_rule *rule,
+			struct flow_match_ip *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_IP, out);
+}
+EXPORT_SYMBOL(flow_rule_match_ip);
+
+void flow_rule_match_ports(const struct flow_rule *rule,
+			   struct flow_match_ports *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_PORTS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_ports);
+
+void flow_rule_match_tcp(const struct flow_rule *rule,
+			 struct flow_match_tcp *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_TCP, out);
+}
+EXPORT_SYMBOL(flow_rule_match_tcp);
+
+void flow_rule_match_icmp(const struct flow_rule *rule,
+			  struct flow_match_icmp *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ICMP, out);
+}
+EXPORT_SYMBOL(flow_rule_match_icmp);
+
+void flow_rule_match_mpls(const struct flow_rule *rule,
+			  struct flow_match_mpls *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_MPLS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_mpls);
+
+void flow_rule_match_enc_control(const struct flow_rule *rule,
+				 struct flow_match_control *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_CONTROL, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_control);
+
+void flow_rule_match_enc_ipv4_addrs(const struct flow_rule *rule,
+				    struct flow_match_ipv4_addrs *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_ipv4_addrs);
+
+void flow_rule_match_enc_ipv6_addrs(const struct flow_rule *rule,
+				    struct flow_match_ipv6_addrs *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_ipv6_addrs);
+
+void flow_rule_match_enc_ip(const struct flow_rule *rule,
+			    struct flow_match_ip *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_IP, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_ip);
+
+void flow_rule_match_enc_ports(const struct flow_rule *rule,
+			       struct flow_match_ports *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_PORTS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_ports);
+
+void flow_rule_match_enc_keyid(const struct flow_rule *rule,
+			       struct flow_match_enc_keyid *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_KEYID, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_keyid);
+
+void flow_rule_match_enc_opts(const struct flow_rule *rule,
+			      struct flow_match_enc_opts *out)
+{
+	FLOW_DISSECTOR_MATCH(rule, FLOW_DISSECTOR_KEY_ENC_OPTS, out);
+}
+EXPORT_SYMBOL(flow_rule_match_enc_opts);
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index f6aa57fbbbaf..aaffea0b66e9 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -381,16 +381,22 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
 	bool skip_sw = tc_skip_sw(f->flags);
 	int err;
 
+	cls_flower.rule = flow_rule_alloc();
+	if (!cls_flower.rule)
+		return -ENOMEM;
+
 	tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, extack);
 	cls_flower.command = TC_CLSFLOWER_REPLACE;
 	cls_flower.cookie = (unsigned long) f;
-	cls_flower.dissector = &f->mask->dissector;
-	cls_flower.mask = &f->mask->key;
-	cls_flower.key = &f->mkey;
+	cls_flower.rule->match.dissector = &f->mask->dissector;
+	cls_flower.rule->match.mask = &f->mask->key;
+	cls_flower.rule->match.key = &f->mkey;
 	cls_flower.exts = &f->exts;
 	cls_flower.classid = f->res.classid;
 
 	err = tc_setup_cb_call(block, TC_SETUP_CLSFLOWER, &cls_flower, skip_sw);
+	kfree(cls_flower.rule);
+
 	if (err < 0) {
 		fl_hw_destroy_filter(tp, f, NULL);
 		return err;
@@ -1463,18 +1469,24 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
 			if (tc_skip_hw(f->flags))
 				continue;
 
+			cls_flower.rule = flow_rule_alloc();
+			if (!cls_flower.rule)
+				return -ENOMEM;
+
 			tc_cls_common_offload_init(&cls_flower.common, tp,
 						   f->flags, extack);
 			cls_flower.command = add ?
 				TC_CLSFLOWER_REPLACE : TC_CLSFLOWER_DESTROY;
 			cls_flower.cookie = (unsigned long)f;
-			cls_flower.dissector = &mask->dissector;
-			cls_flower.mask = &mask->key;
-			cls_flower.key = &f->mkey;
+			cls_flower.rule->match.dissector = &mask->dissector;
+			cls_flower.rule->match.mask = &mask->key;
+			cls_flower.rule->match.key = &f->mkey;
 			cls_flower.exts = &f->exts;
 			cls_flower.classid = f->res.classid;
 
 			err = cb(TC_SETUP_CLSFLOWER, &cls_flower, cb_priv);
+			kfree(cls_flower.rule);
+
 			if (err) {
 				if (add && tc_skip_sw(f->flags))
 					return err;
@@ -1489,25 +1501,32 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
 	return 0;
 }
 
-static void fl_hw_create_tmplt(struct tcf_chain *chain,
-			       struct fl_flow_tmplt *tmplt)
+static int fl_hw_create_tmplt(struct tcf_chain *chain,
+			      struct fl_flow_tmplt *tmplt)
 {
 	struct tc_cls_flower_offload cls_flower = {};
 	struct tcf_block *block = chain->block;
 	struct tcf_exts dummy_exts = { 0, };
 
+	cls_flower.rule = flow_rule_alloc();
+	if (!cls_flower.rule)
+		return -ENOMEM;
+
 	cls_flower.common.chain_index = chain->index;
 	cls_flower.command = TC_CLSFLOWER_TMPLT_CREATE;
 	cls_flower.cookie = (unsigned long) tmplt;
-	cls_flower.dissector = &tmplt->dissector;
-	cls_flower.mask = &tmplt->mask;
-	cls_flower.key = &tmplt->dummy_key;
+	cls_flower.rule->match.dissector = &tmplt->dissector;
+	cls_flower.rule->match.mask = &tmplt->mask;
+	cls_flower.rule->match.key = &tmplt->dummy_key;
 	cls_flower.exts = &dummy_exts;
 
 	/* We don't care if driver (any of them) fails to handle this
 	 * call. It serves just as a hint for it.
 	 */
 	tc_setup_cb_call(block, TC_SETUP_CLSFLOWER, &cls_flower, false);
+	kfree(cls_flower.rule);
+
+	return 0;
 }
 
 static void fl_hw_destroy_tmplt(struct tcf_chain *chain,
@@ -1551,12 +1570,14 @@ static void *fl_tmplt_create(struct net *net, struct tcf_chain *chain,
 	err = fl_set_key(net, tb, &tmplt->dummy_key, &tmplt->mask, extack);
 	if (err)
 		goto errout_tmplt;
-	kfree(tb);
 
 	fl_init_dissector(&tmplt->dissector, &tmplt->mask);
 
-	fl_hw_create_tmplt(chain, tmplt);
+	err = fl_hw_create_tmplt(chain, tmplt);
+	if (err)
+		goto errout_tmplt;
 
+	kfree(tb);
 	return tmplt;
 
 errout_tmplt: