byteorder.c
/*
* (C) 2012-2013 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 <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/expr.h>
#include <libnftnl/rule.h>
struct nftnl_expr_byteorder {
enum nft_registers sreg;
enum nft_registers dreg;
enum nft_byteorder_ops op;
unsigned int len;
unsigned int size;
};
static int
nftnl_expr_byteorder_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_BYTEORDER_SREG:
memcpy(&byteorder->sreg, data, sizeof(byteorder->sreg));
break;
case NFTNL_EXPR_BYTEORDER_DREG:
memcpy(&byteorder->dreg, data, sizeof(byteorder->dreg));
break;
case NFTNL_EXPR_BYTEORDER_OP:
memcpy(&byteorder->op, data, sizeof(byteorder->op));
break;
case NFTNL_EXPR_BYTEORDER_LEN:
memcpy(&byteorder->len, data, sizeof(byteorder->len));
break;
case NFTNL_EXPR_BYTEORDER_SIZE:
memcpy(&byteorder->size, data, sizeof(byteorder->size));
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_byteorder_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_BYTEORDER_SREG:
*data_len = sizeof(byteorder->sreg);
return &byteorder->sreg;
case NFTNL_EXPR_BYTEORDER_DREG:
*data_len = sizeof(byteorder->dreg);
return &byteorder->dreg;
case NFTNL_EXPR_BYTEORDER_OP:
*data_len = sizeof(byteorder->op);
return &byteorder->op;
case NFTNL_EXPR_BYTEORDER_LEN:
*data_len = sizeof(byteorder->len);
return &byteorder->len;
case NFTNL_EXPR_BYTEORDER_SIZE:
*data_len = sizeof(byteorder->size);
return &byteorder->size;
}
return NULL;
}
static int nftnl_expr_byteorder_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_BYTEORDER_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_BYTEORDER_SREG:
case NFTA_BYTEORDER_DREG:
case NFTA_BYTEORDER_OP:
case NFTA_BYTEORDER_LEN:
case NFTA_BYTEORDER_SIZE:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_byteorder_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SREG)) {
mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SREG,
htonl(byteorder->sreg));
}
if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_DREG)) {
mnl_attr_put_u32(nlh, NFTA_BYTEORDER_DREG,
htonl(byteorder->dreg));
}
if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_OP)) {
mnl_attr_put_u32(nlh, NFTA_BYTEORDER_OP,
htonl(byteorder->op));
}
if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_LEN)) {
mnl_attr_put_u32(nlh, NFTA_BYTEORDER_LEN,
htonl(byteorder->len));
}
if (e->flags & (1 << NFTNL_EXPR_BYTEORDER_SIZE)) {
mnl_attr_put_u32(nlh, NFTA_BYTEORDER_SIZE,
htonl(byteorder->size));
}
}
static int
nftnl_expr_byteorder_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
struct nlattr *tb[NFTA_BYTEORDER_MAX+1] = {};
int ret = 0;
if (mnl_attr_parse_nested(attr, nftnl_expr_byteorder_cb, tb) < 0)
return -1;
if (tb[NFTA_BYTEORDER_SREG]) {
byteorder->sreg =
ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SREG]));
e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SREG);
}
if (tb[NFTA_BYTEORDER_DREG]) {
byteorder->dreg =
ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_DREG]));
e->flags |= (1 << NFTNL_EXPR_BYTEORDER_DREG);
}
if (tb[NFTA_BYTEORDER_OP]) {
byteorder->op =
ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_OP]));
e->flags |= (1 << NFTNL_EXPR_BYTEORDER_OP);
}
if (tb[NFTA_BYTEORDER_LEN]) {
byteorder->len =
ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_LEN]));
e->flags |= (1 << NFTNL_EXPR_BYTEORDER_LEN);
}
if (tb[NFTA_BYTEORDER_SIZE]) {
byteorder->size =
ntohl(mnl_attr_get_u32(tb[NFTA_BYTEORDER_SIZE]));
e->flags |= (1 << NFTNL_EXPR_BYTEORDER_SIZE);
}
return ret;
}
static const char *expr_byteorder_str[] = {
[NFT_BYTEORDER_HTON] = "hton",
[NFT_BYTEORDER_NTOH] = "ntoh",
};
static const char *bo2str(uint32_t type)
{
if (type > NFT_BYTEORDER_HTON)
return "unknown";
return expr_byteorder_str[type];
}
static inline int nftnl_str2ntoh(const char *op)
{
if (strcmp(op, "ntoh") == 0)
return NFT_BYTEORDER_NTOH;
else if (strcmp(op, "hton") == 0)
return NFT_BYTEORDER_HTON;
else {
errno = EINVAL;
return -1;
}
}
static int nftnl_expr_byteorder_snprintf_default(char *buf, size_t size,
const struct nftnl_expr *e)
{
struct nftnl_expr_byteorder *byteorder = nftnl_expr_data(e);
int remain = size, offset = 0, ret;
ret = snprintf(buf, remain, "reg %u = %s(reg %u, %u, %u) ",
byteorder->dreg, bo2str(byteorder->op),
byteorder->sreg, byteorder->size, byteorder->len);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
return offset;
}
static int
nftnl_expr_byteorder_snprintf(char *buf, size_t size, uint32_t type,
uint32_t flags, const struct nftnl_expr *e)
{
switch (type) {
case NFTNL_OUTPUT_DEFAULT:
return nftnl_expr_byteorder_snprintf_default(buf, size, e);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
struct expr_ops expr_ops_byteorder = {
.name = "byteorder",
.alloc_len = sizeof(struct nftnl_expr_byteorder),
.max_attr = NFTA_BYTEORDER_MAX,
.set = nftnl_expr_byteorder_set,
.get = nftnl_expr_byteorder_get,
.parse = nftnl_expr_byteorder_parse,
.build = nftnl_expr_byteorder_build,
.snprintf = nftnl_expr_byteorder_snprintf,
};
nftnl_expr_byteorder
Definition: byteorder.c:24