src: add offset attribute for hash expression

Add support to add an offset to the hash generator, eg.

 ct mark set hash ip saddr mod 10 offset 100

This will generate marks with series between 100-109.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/hash.c b/src/hash.c
index 125b3202..d26b2eda 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -22,13 +22,16 @@ static void hash_expr_print(const struct expr *expr)
 	printf(" mod %u", expr->hash.mod);
 	if (expr->hash.seed)
 		printf(" seed 0x%x", expr->hash.seed);
+	if (expr->hash.offset)
+		printf(" offset %u", expr->hash.offset);
 }
 
 static bool hash_expr_cmp(const struct expr *e1, const struct expr *e2)
 {
 	return expr_cmp(e1->hash.expr, e2->hash.expr) &&
 	       e1->hash.mod == e2->hash.mod &&
-	       e1->hash.seed == e2->hash.seed;
+	       e1->hash.seed == e2->hash.seed &&
+	       e1->hash.offset == e2->hash.offset;
 }
 
 static void hash_expr_clone(struct expr *new, const struct expr *expr)
@@ -36,6 +39,7 @@ static void hash_expr_clone(struct expr *new, const struct expr *expr)
 	new->hash.expr = expr_clone(expr->hash.expr);
 	new->hash.mod = expr->hash.mod;
 	new->hash.seed = expr->hash.seed;
+	new->hash.offset = expr->hash.offset;
 }
 
 static const struct expr_ops hash_expr_ops = {
@@ -47,7 +51,7 @@ static const struct expr_ops hash_expr_ops = {
 };
 
 struct expr *hash_expr_alloc(const struct location *loc, uint32_t mod,
-			     uint32_t seed)
+			     uint32_t seed, uint32_t offset)
 {
 	struct expr *expr;
 
@@ -55,6 +59,7 @@ struct expr *hash_expr_alloc(const struct location *loc, uint32_t mod,
 			  BYTEORDER_HOST_ENDIAN, 4 * BITS_PER_BYTE);
 	expr->hash.mod  = mod;
 	expr->hash.seed = seed;
+	expr->hash.offset = offset;
 
 	return expr;
 }