last.c

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * (C) 2016 by Pablo Neira Ayuso <pablo@netfilter.org>
 */

#include <stdio.h>
#include <stdint.h>
#include <arpa/inet.h>
#include <errno.h>
#include <inttypes.h>

#include <linux/netfilter/nf_tables.h>

#include "internal.h"
#include <libmnl/libmnl.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>

struct nftnl_expr_last {
        uint64_t        msecs;
        uint32_t        set;
};

static int
nftnl_expr_last_set(struct nftnl_expr *e, uint16_t type,
                    const void *data, uint32_t data_len, uint32_t byteorder)
{
        struct nftnl_expr_last *last = nftnl_expr_data(e);

        switch (type) {
        case NFTNL_EXPR_LAST_MSECS:
                memcpy(&last->msecs, data, data_len);
                break;
        case NFTNL_EXPR_LAST_SET:
                memcpy(&last->set, data, data_len);
                break;
        }
        return 0;
}

static const void *nftnl_expr_last_get(const struct nftnl_expr *e,
                                        uint16_t type, uint32_t *data_len)
{
        struct nftnl_expr_last *last = nftnl_expr_data(e);

        switch (type) {
        case NFTNL_EXPR_LAST_MSECS:
                *data_len = sizeof(last->msecs);
                return &last->msecs;
        case NFTNL_EXPR_LAST_SET:
                *data_len = sizeof(last->set);
                return &last->set;
        }
        return NULL;
}

static int nftnl_expr_last_cb(const struct nlattr *attr, void *data)
{
        int type = mnl_attr_get_type(attr);
        const struct nlattr **tb = data;

        if (mnl_attr_type_valid(attr, NFTA_LAST_MAX) < 0)
                return MNL_CB_OK;

        switch(type) {
        case NFTA_LAST_MSECS:
                if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0)
                        abi_breakage();
                break;
        case NFTA_LAST_SET:
                if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
                        abi_breakage();
                break;
        }

        tb[type] = attr;
        return MNL_CB_OK;
}

static void
nftnl_expr_last_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
        struct nftnl_expr_last *last = nftnl_expr_data(e);

        if (e->flags & (1 << NFTNL_EXPR_LAST_MSECS))
                mnl_attr_put_u64(nlh, NFTA_LAST_MSECS, htobe64(last->msecs));
        if (e->flags & (1 << NFTNL_EXPR_LAST_SET))
                mnl_attr_put_u32(nlh, NFTA_LAST_SET, htonl(last->set));
}

static int
nftnl_expr_last_parse(struct nftnl_expr *e, struct nlattr *attr)
{
        struct nftnl_expr_last *last = nftnl_expr_data(e);
        struct nlattr *tb[NFTA_LAST_MAX + 1] = {};

        if (mnl_attr_parse_nested(attr, nftnl_expr_last_cb, tb) < 0)
                return -1;

        if (tb[NFTA_LAST_MSECS]) {
                last->msecs = be64toh(mnl_attr_get_u64(tb[NFTA_LAST_MSECS]));
                e->flags |= (1 << NFTNL_EXPR_LAST_MSECS);
        }
        if (tb[NFTA_LAST_SET]) {
                last->set = ntohl(mnl_attr_get_u32(tb[NFTA_LAST_SET]));
                e->flags |= (1 << NFTNL_EXPR_LAST_SET);
        }

        return 0;
}

static int nftnl_expr_last_snprintf(char *buf, size_t len,
                                       uint32_t flags,
                                       const struct nftnl_expr *e)
{
        struct nftnl_expr_last *last = nftnl_expr_data(e);

        if (!last->set)
                return snprintf(buf, len, "never ");

        return snprintf(buf, len, "%"PRIu64" ", last->msecs);
}

static struct attr_policy last_attr_policy[__NFTNL_EXPR_LAST_MAX] = {
        [NFTNL_EXPR_LAST_MSECS] = { .maxlen = sizeof(uint64_t) },
        [NFTNL_EXPR_LAST_SET]   = { .maxlen = sizeof(uint32_t) },
};

struct expr_ops expr_ops_last = {
        .name           = "last",
        .alloc_len      = sizeof(struct nftnl_expr_last),
        .nftnl_max_attr = __NFTNL_EXPR_LAST_MAX - 1,
        .attr_policy    = last_attr_policy,
        .set            = nftnl_expr_last_set,
        .get            = nftnl_expr_last_get,
        .parse          = nftnl_expr_last_parse,
        .build          = nftnl_expr_last_build,
        .output         = nftnl_expr_last_snprintf,
};