immediate.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 <stdio.h>
#include <stdint.h>
#include <string.h>
#include <arpa/inet.h>
#include <errno.h>
#include "internal.h"
#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>
struct nftnl_expr_immediate {
union nftnl_data_reg data;
enum nft_registers dreg;
};
static int
nftnl_expr_immediate_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_IMM_DREG:
memcpy(&imm->dreg, data, sizeof(imm->dreg));
break;
case NFTNL_EXPR_IMM_DATA:
memcpy(&imm->data.val, data, data_len);
imm->data.len = data_len;
break;
case NFTNL_EXPR_IMM_VERDICT:
memcpy(&imm->data.verdict, data, sizeof(imm->data.verdict));
break;
case NFTNL_EXPR_IMM_CHAIN:
if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
xfree(imm->data.chain);
imm->data.chain = strdup(data);
if (!imm->data.chain)
return -1;
break;
case NFTNL_EXPR_IMM_CHAIN_ID:
memcpy(&imm->data.chain_id, data, sizeof(uint32_t));
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_IMM_DREG:
*data_len = sizeof(imm->dreg);
return &imm->dreg;
case NFTNL_EXPR_IMM_DATA:
*data_len = imm->data.len;
return &imm->data.val;
case NFTNL_EXPR_IMM_VERDICT:
*data_len = sizeof(imm->data.verdict);
return &imm->data.verdict;
case NFTNL_EXPR_IMM_CHAIN:
*data_len = strlen(imm->data.chain)+1;
return imm->data.chain;
case NFTNL_EXPR_IMM_CHAIN_ID:
*data_len = sizeof(imm->data.chain_id);
return &imm->data.chain_id;
}
return NULL;
}
static int nftnl_expr_immediate_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_IMMEDIATE_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_IMMEDIATE_DREG:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
case NFTA_IMMEDIATE_DATA:
if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
/* Sane configurations allows you to set ONLY one of these two below */
if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
struct nlattr *nest;
nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
mnl_attr_nest_end(nlh, nest);
} else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
struct nlattr *nest1, *nest2;
nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) {
mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID,
htonl(imm->data.chain_id));
}
mnl_attr_nest_end(nlh, nest1);
mnl_attr_nest_end(nlh, nest2);
}
}
static int
nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
int ret = 0;
if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
return -1;
if (tb[NFTA_IMMEDIATE_DREG]) {
imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
}
if (tb[NFTA_IMMEDIATE_DATA]) {
int type;
ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
if (ret < 0)
return ret;
switch(type) {
case DATA_VALUE:
/* real immediate data to be loaded to destination */
e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
break;
case DATA_VERDICT:
/* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
break;
case DATA_CHAIN:
/* NFTNL_GOTO and NFTNL_JUMP case */
e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
(1 << NFTNL_EXPR_IMM_CHAIN);
break;
}
}
return ret;
}
static int
nftnl_expr_immediate_snprintf_default(char *buf, size_t len,
const struct nftnl_expr *e,
uint32_t flags)
{
int remain = len, offset = 0, ret;
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
ret = snprintf(buf, remain, "reg %u ", imm->dreg);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
NFTNL_OUTPUT_DEFAULT, flags, DATA_VALUE);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
} else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
NFTNL_OUTPUT_DEFAULT, flags, DATA_VERDICT);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
} else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
NFTNL_OUTPUT_DEFAULT, flags, DATA_CHAIN);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
}
return offset;
}
static int
nftnl_expr_immediate_snprintf(char *buf, size_t len, uint32_t type,
uint32_t flags, const struct nftnl_expr *e)
{
switch(type) {
case NFTNL_OUTPUT_DEFAULT:
return nftnl_expr_immediate_snprintf_default(buf, len, e, flags);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
static void nftnl_expr_immediate_free(const struct nftnl_expr *e)
{
struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT))
nftnl_free_verdict(&imm->data);
}
struct expr_ops expr_ops_immediate = {
.name = "immediate",
.alloc_len = sizeof(struct nftnl_expr_immediate),
.max_attr = NFTA_IMMEDIATE_MAX,
.free = nftnl_expr_immediate_free,
.set = nftnl_expr_immediate_set,
.get = nftnl_expr_immediate_get,
.parse = nftnl_expr_immediate_parse,
.build = nftnl_expr_immediate_build,
.snprintf = nftnl_expr_immediate_snprintf,
};
nftnl_expr_immediate
Definition: immediate.c:23