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>

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: