flow_offload.c

#include "internal.h"

#include <stdio.h>
#include <stdint.h>
#include <string.h> /* for memcpy */
#include <arpa/inet.h>
#include <errno.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/rule.h>
#include <libnftnl/expr.h>

struct nftnl_expr_flow {
        char                    *table_name;
};

static int
nftnl_expr_flow_set(struct nftnl_expr *e, uint16_t type,
                    const void *data, uint32_t data_len, uint32_t byteorder)
{
        struct nftnl_expr_flow *flow = nftnl_expr_data(e);

        switch (type) {
        case NFTNL_EXPR_FLOW_TABLE_NAME:
                flow->table_name = strdup((const char *)data);
                if (!flow->table_name)
                        return -1;
                break;
        }
        return 0;
}

static const void *nftnl_expr_flow_get(const struct nftnl_expr *e,
                                       uint16_t type, uint32_t *data_len)
{
        struct nftnl_expr_flow *flow = nftnl_expr_data(e);

        switch(type) {
        case NFTNL_EXPR_FLOW_TABLE_NAME:
                *data_len = strlen(flow->table_name) + 1;
                return flow->table_name;
        }
        return NULL;
}

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

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

        switch(type) {
        case NFTA_FLOW_TABLE_NAME:
                if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
                        abi_breakage();
                break;
        }

        tb[type] = attr;
        return MNL_CB_OK;
}

static void nftnl_expr_flow_build(struct nlmsghdr *nlh,
                                  const struct nftnl_expr *e)
{
        struct nftnl_expr_flow *flow = nftnl_expr_data(e);

        if (e->flags & (1 << NFTNL_EXPR_FLOW_TABLE_NAME))
                mnl_attr_put_strz(nlh, NFTA_FLOW_TABLE_NAME, flow->table_name);
}

static int nftnl_expr_flow_parse(struct nftnl_expr *e, struct nlattr *attr)
{
        struct nftnl_expr_flow *flow = nftnl_expr_data(e);
        struct nlattr *tb[NFTA_FLOW_MAX+1] = {};
        int ret = 0;

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

        if (nftnl_parse_str_attr(tb[NFTA_FLOW_TABLE_NAME],
                                 NFTNL_EXPR_FLOW_TABLE_NAME,
                                 (const char **)&flow->table_name,
                                 &e->flags) < 0)
                return -1;

        return ret;
}

static int nftnl_expr_flow_snprintf(char *buf, size_t remain,
                                    uint32_t flags, const struct nftnl_expr *e)
{
        struct nftnl_expr_flow *l = nftnl_expr_data(e);
        int offset = 0, ret;

        ret = snprintf(buf, remain, "flowtable %s ", l->table_name);
        SNPRINTF_BUFFER_SIZE(ret, remain, offset);

        return offset;
}

static void nftnl_expr_flow_free(const struct nftnl_expr *e)
{
        struct nftnl_expr_flow *flow = nftnl_expr_data(e);

        xfree(flow->table_name);
}

static struct attr_policy flow_offload_attr_policy[__NFTNL_EXPR_FLOW_MAX] = {
        [NFTNL_EXPR_FLOW_TABLE_NAME] = { .maxlen = NFT_NAME_MAXLEN },
};

struct expr_ops expr_ops_flow = {
        .name           = "flow_offload",
        .alloc_len      = sizeof(struct nftnl_expr_flow),
        .nftnl_max_attr = __NFTNL_EXPR_FLOW_MAX - 1,
        .attr_policy    = flow_offload_attr_policy,
        .free           = nftnl_expr_flow_free,
        .set            = nftnl_expr_flow_set,
        .get            = nftnl_expr_flow_get,
        .parse          = nftnl_expr_flow_parse,
        .build          = nftnl_expr_flow_build,
        .output         = nftnl_expr_flow_snprintf,
};