optimize: merge rules with same selectors into a concatenation

This patch extends the ruleset optimization infrastructure to collapse
several rules with the same selectors into a concatenation.

Transform:

  meta iifname eth1 ip saddr 1.1.1.1 ip daddr 2.2.2.3 accept
  meta iifname eth1 ip saddr 1.1.1.2 ip daddr 2.2.2.5 accept
  meta iifname eth2 ip saddr 1.1.1.3 ip daddr 2.2.2.6 accept

into:

  meta iifname . ip saddr . ip daddr { eth1 . 1.1.1.1 . 2.2.2.6, eth1 . 1.1.1.2 . 2.2.2.5 , eth1 . 1.1.1.3 . 2.2.2.6 } accept

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 43 insertions, 1 deletions

diff --git a/src/optimize.c b/src/optimize.c
index bae36d76..5950e852 100644
--- a/src/optimize.c
+++ b/src/optimize.c
@@ -271,6 +271,48 @@ static void merge_stmts(const struct optimize_ctx *ctx,
 	stmt_a->expr->right = set;
 }
 
+static void merge_concat_stmts(const struct optimize_ctx *ctx,
+			       uint32_t from, uint32_t to,
+			       const struct merge *merge)
+{
+	struct expr *concat, *elem, *set;
+	struct stmt *stmt, *stmt_a;
+	uint32_t i, k;
+
+	stmt = ctx->stmt_matrix[from][merge->stmt[0]];
+	/* build concatenation of selectors, eg. ifname . ip daddr . tcp dport */
+	concat = concat_expr_alloc(&internal_location);
+
+	for (k = 0; k < merge->num_stmts; k++) {
+		stmt_a = ctx->stmt_matrix[from][merge->stmt[k]];
+		compound_expr_add(concat, expr_get(stmt_a->expr->left));
+	}
+	expr_free(stmt->expr->left);
+	stmt->expr->left = concat;
+
+	/* build set data contenation, eg. { eth0 . 1.1.1.1 . 22 } */
+	set = set_expr_alloc(&internal_location, NULL);
+	set->set_flags |= NFT_SET_ANONYMOUS;
+
+	for (i = from; i <= to; i++) {
+		concat = concat_expr_alloc(&internal_location);
+		for (k = 0; k < merge->num_stmts; k++) {
+			stmt_a = ctx->stmt_matrix[i][merge->stmt[k]];
+			compound_expr_add(concat, expr_get(stmt_a->expr->right));
+		}
+		elem = set_elem_expr_alloc(&internal_location, concat);
+		compound_expr_add(set, elem);
+	}
+	expr_free(stmt->expr->right);
+	stmt->expr->right = set;
+
+	for (k = 1; k < merge->num_stmts; k++) {
+		stmt_a = ctx->stmt_matrix[from][merge->stmt[k]];
+		list_del(&stmt_a->list);
+		stmt_free(stmt_a);
+	}
+}
+
 static void rule_optimize_print(struct output_ctx *octx,
 				const struct rule *rule)
 {
@@ -312,7 +354,7 @@ static void merge_rules(const struct optimize_ctx *ctx,
 	uint32_t i;
 
 	if (merge->num_stmts > 1) {
-		return;
+		merge_concat_stmts(ctx, from, to, merge);
 	} else {
 		merge_stmts(ctx, from, to, merge);
 	}