hash.c

/*
 * 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:
                octx->print(octx->ctx, "symhash");
        break;
        case NFT_HASH_JENKINS:
        default:
                octx->print(octx->ctx, "jhash ");
                expr_print(expr->hash.expr, octx);
        }

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