/*
 * Hash expression definitions.
 *
 * Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <nftables.h>
#include <expression.h>
#include <datatype.h>
#include <gmputil.h>
#include <hash.h>
#include <utils.h>

static void hash_expr_print(const struct expr *expr, struct output_ctx *octx)
{
	switch (expr->hash.type) {
	case NFT_HASH_SYM:
		nft_print(octx, "symhash");
	break;
	case NFT_HASH_JENKINS:
	default:
		nft_print(octx, "jhash ");
		expr_print(expr->hash.expr, octx);
	}

	nft_print(octx, " mod %u", expr->hash.mod);
	if (expr->hash.seed_set)
		nft_print(octx, " seed 0x%x", expr->hash.seed);
	if (expr->hash.offset)
		nft_print(octx, " offset %u", expr->hash.offset);
}

static bool hash_expr_cmp(const struct expr *e1, const struct expr *e2)
{
	return (e1->hash.expr ||
		expr_cmp(e1->hash.expr, e2->hash.expr)) &&
	       e1->hash.mod == e2->hash.mod &&
	       e1->hash.seed_set == e2->hash.seed_set &&
	       e1->hash.seed == e2->hash.seed &&
	       e1->hash.offset == e2->hash.offset &&
	       e1->hash.type == e2->hash.type;
}

static void hash_expr_clone(struct expr *new, const struct expr *expr)
{
	if (expr->hash.expr)
		new->hash.expr = expr_clone(expr->hash.expr);
	new->hash.mod = expr->hash.mod;
	new->hash.seed_set = expr->hash.seed_set;
	new->hash.seed = expr->hash.seed;
	new->hash.offset = expr->hash.offset;
	new->hash.type = expr->hash.type;
}

static const struct expr_ops hash_expr_ops = {
	.type		= EXPR_HASH,
	.name		= "hash",
	.print		= hash_expr_print,
	.cmp		= hash_expr_cmp,
	.clone		= hash_expr_clone,
};

struct expr *hash_expr_alloc(const struct location *loc,
			     uint32_t mod,
			     bool seed_set, uint32_t seed,
			     uint32_t offset,
			     enum nft_hash_types type)
{
	struct expr *expr;

	expr = expr_alloc(loc, &hash_expr_ops, &integer_type,
			  BYTEORDER_HOST_ENDIAN, 4 * BITS_PER_BYTE);
	expr->hash.mod  = mod;
	expr->hash.seed_set = seed_set;
	expr->hash.seed = seed;
	expr->hash.offset = offset;
	expr->hash.type = type;

	return expr;
}
