expr.c
/*
* (C) 2012 by 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 as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This code has been sponsored by Sophos Astaro <http://www.sophos.com>
*/
#include "internal.h"
#include <time.h>
#include <endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/expr.h>
EXPORT_SYMBOL(nftnl_expr_alloc);
struct nftnl_expr *nftnl_expr_alloc(const char *name)
{
struct nftnl_expr *expr;
struct expr_ops *ops;
ops = nftnl_expr_ops_lookup(name);
if (ops == NULL)
return NULL;
expr = calloc(1, sizeof(struct nftnl_expr) + ops->alloc_len);
if (expr == NULL)
return NULL;
/* Manually set expression name attribute */
expr->flags |= (1 << NFTNL_EXPR_NAME);
expr->ops = ops;
if (ops->init)
ops->init(expr);
return expr;
}
EXPORT_SYMBOL(nftnl_expr_free);
void nftnl_expr_free(const struct nftnl_expr *expr)
{
if (expr->ops->free)
expr->ops->free(expr);
xfree(expr);
}
EXPORT_SYMBOL(nftnl_expr_is_set);
bool nftnl_expr_is_set(const struct nftnl_expr *expr, uint16_t type)
{
return expr->flags & (1 << type);
}
EXPORT_SYMBOL(nftnl_expr_set);
int nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
const void *data, uint32_t data_len)
{
switch(type) {
case NFTNL_EXPR_NAME: /* cannot be modified */
return 0;
default:
if (expr->ops->set(expr, type, data, data_len) < 0)
return -1;
}
expr->flags |= (1 << type);
return 0;
}
EXPORT_SYMBOL(nftnl_expr_set_u8);
void
nftnl_expr_set_u8(struct nftnl_expr *expr, uint16_t type, uint8_t data)
{
nftnl_expr_set(expr, type, &data, sizeof(uint8_t));
}
EXPORT_SYMBOL(nftnl_expr_set_u16);
void
nftnl_expr_set_u16(struct nftnl_expr *expr, uint16_t type, uint16_t data)
{
nftnl_expr_set(expr, type, &data, sizeof(uint16_t));
}
EXPORT_SYMBOL(nftnl_expr_set_u32);
void
nftnl_expr_set_u32(struct nftnl_expr *expr, uint16_t type, uint32_t data)
{
nftnl_expr_set(expr, type, &data, sizeof(uint32_t));
}
EXPORT_SYMBOL(nftnl_expr_set_u64);
void
nftnl_expr_set_u64(struct nftnl_expr *expr, uint16_t type, uint64_t data)
{
nftnl_expr_set(expr, type, &data, sizeof(uint64_t));
}
EXPORT_SYMBOL(nftnl_expr_set_str);
int nftnl_expr_set_str(struct nftnl_expr *expr, uint16_t type, const char *str)
{
return nftnl_expr_set(expr, type, str, strlen(str) + 1);
}
EXPORT_SYMBOL(nftnl_expr_get);
const void *nftnl_expr_get(const struct nftnl_expr *expr,
uint16_t type, uint32_t *data_len)
{
const void *ret;
if (!(expr->flags & (1 << type)))
return NULL;
switch(type) {
case NFTNL_EXPR_NAME:
*data_len = strlen(expr->ops->name) + 1;
ret = expr->ops->name;
break;
default:
ret = expr->ops->get(expr, type, data_len);
break;
}
return ret;
}
EXPORT_SYMBOL(nftnl_expr_get_u8);
uint8_t nftnl_expr_get_u8(const struct nftnl_expr *expr, uint16_t type)
{
const void *data;
uint32_t data_len;
data = nftnl_expr_get(expr, type, &data_len);
if (data == NULL)
return 0;
if (data_len != sizeof(uint8_t))
return 0;
return *((uint8_t *)data);
}
EXPORT_SYMBOL(nftnl_expr_get_u16);
uint16_t nftnl_expr_get_u16(const struct nftnl_expr *expr, uint16_t type)
{
const void *data;
uint32_t data_len;
data = nftnl_expr_get(expr, type, &data_len);
if (data == NULL)
return 0;
if (data_len != sizeof(uint16_t))
return 0;
return *((uint16_t *)data);
}
EXPORT_SYMBOL(nftnl_expr_get_u32);
uint32_t nftnl_expr_get_u32(const struct nftnl_expr *expr, uint16_t type)
{
const void *data;
uint32_t data_len;
data = nftnl_expr_get(expr, type, &data_len);
if (data == NULL)
return 0;
if (data_len != sizeof(uint32_t))
return 0;
return *((uint32_t *)data);
}
EXPORT_SYMBOL(nftnl_expr_get_u64);
uint64_t nftnl_expr_get_u64(const struct nftnl_expr *expr, uint16_t type)
{
const void *data;
uint32_t data_len;
data = nftnl_expr_get(expr, type, &data_len);
if (data == NULL)
return 0;
if (data_len != sizeof(uint64_t))
return 0;
return *((uint64_t *)data);
}
EXPORT_SYMBOL(nftnl_expr_get_str);
const char *nftnl_expr_get_str(const struct nftnl_expr *expr, uint16_t type)
{
uint32_t data_len;
return (const char *)nftnl_expr_get(expr, type, &data_len);
}
EXPORT_SYMBOL(nftnl_expr_build_payload);
void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
{
struct nlattr *nest;
mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
if (!expr->ops->build)
return;
nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
expr->ops->build(nlh, expr);
mnl_attr_nest_end(nlh, nest);
}
static int nftnl_rule_parse_expr_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_EXPR_MAX) < 0)
return MNL_CB_OK;
switch (type) {
case NFTA_EXPR_NAME:
if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
abi_breakage();
break;
case NFTA_EXPR_DATA:
if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
{
struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
struct nftnl_expr *expr;
if (mnl_attr_parse_nested(attr, nftnl_rule_parse_expr_cb, tb) < 0)
goto err1;
expr = nftnl_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
if (expr == NULL)
goto err1;
if (tb[NFTA_EXPR_DATA] &&
expr->ops->parse &&
expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
goto err2;
return expr;
err2:
xfree(expr);
err1:
return NULL;
}
EXPORT_SYMBOL(nftnl_expr_snprintf);
int nftnl_expr_snprintf(char *buf, size_t size, const struct nftnl_expr *expr,
uint32_t type, uint32_t flags)
{
int ret;
unsigned int offset = 0, remain = size;
if (size)
buf[0] = '\0';
if (!expr->ops->snprintf)
return 0;
ret = expr->ops->snprintf(buf + offset, remain, type, flags, expr);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
return offset;
}
static int nftnl_expr_do_snprintf(char *buf, size_t size, const void *e,
uint32_t cmd, uint32_t type, uint32_t flags)
{
return nftnl_expr_snprintf(buf, size, e, type, flags);
}
EXPORT_SYMBOL(nftnl_expr_fprintf);
int nftnl_expr_fprintf(FILE *fp, const struct nftnl_expr *expr, uint32_t type,
uint32_t flags)
{
return nftnl_fprintf(fp, expr, NFTNL_CMD_UNSPEC, type, flags,
nftnl_expr_do_snprintf);
}