match.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 <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 <linux/netfilter/nf_tables_compat.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>
/* From include/linux/netfilter/x_tables.h */
#define XT_EXTENSION_MAXNAMELEN 29
struct nftnl_expr_match {
char name[XT_EXTENSION_MAXNAMELEN];
uint32_t rev;
uint32_t data_len;
const void *data;
};
static int
nftnl_expr_match_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_match *mt = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_MT_NAME:
snprintf(mt->name, sizeof(mt->name), "%.*s", data_len,
(const char *)data);
break;
case NFTNL_EXPR_MT_REV:
memcpy(&mt->rev, data, sizeof(mt->rev));
break;
case NFTNL_EXPR_MT_INFO:
if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
xfree(mt->data);
mt->data = data;
mt->data_len = data_len;
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_match_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_match *mt = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_MT_NAME:
*data_len = sizeof(mt->name);
return mt->name;
case NFTNL_EXPR_MT_REV:
*data_len = sizeof(mt->rev);
return &mt->rev;
case NFTNL_EXPR_MT_INFO:
*data_len = mt->data_len;
return mt->data;
}
return NULL;
}
static int nftnl_expr_match_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_MATCH_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_MATCH_NAME:
if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0)
abi_breakage();
break;
case NFTA_MATCH_REV:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
case NFTA_MATCH_INFO:
if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_match_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_match *mt = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_MT_NAME))
mnl_attr_put_strz(nlh, NFTA_MATCH_NAME, mt->name);
if (e->flags & (1 << NFTNL_EXPR_MT_REV))
mnl_attr_put_u32(nlh, NFTA_MATCH_REV, htonl(mt->rev));
if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
mnl_attr_put(nlh, NFTA_MATCH_INFO, mt->data_len, mt->data);
}
static int nftnl_expr_match_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_match *match = nftnl_expr_data(e);
struct nlattr *tb[NFTA_MATCH_MAX+1] = {};
if (mnl_attr_parse_nested(attr, nftnl_expr_match_cb, tb) < 0)
return -1;
if (tb[NFTA_MATCH_NAME]) {
snprintf(match->name, XT_EXTENSION_MAXNAMELEN, "%s",
mnl_attr_get_str(tb[NFTA_MATCH_NAME]));
match->name[XT_EXTENSION_MAXNAMELEN-1] = '\0';
e->flags |= (1 << NFTNL_EXPR_MT_NAME);
}
if (tb[NFTA_MATCH_REV]) {
match->rev = ntohl(mnl_attr_get_u32(tb[NFTA_MATCH_REV]));
e->flags |= (1 << NFTNL_EXPR_MT_REV);
}
if (tb[NFTA_MATCH_INFO]) {
uint32_t len = mnl_attr_get_payload_len(tb[NFTA_MATCH_INFO]);
void *match_data;
if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
xfree(match->data);
match_data = calloc(1, len);
if (match_data == NULL)
return -1;
memcpy(match_data, mnl_attr_get_payload(tb[NFTA_MATCH_INFO]), len);
match->data = match_data;
match->data_len = len;
e->flags |= (1 << NFTNL_EXPR_MT_INFO);
}
return 0;
}
static int
nftnl_expr_match_snprintf(char *buf, size_t len, uint32_t type,
uint32_t flags, const struct nftnl_expr *e)
{
struct nftnl_expr_match *match = nftnl_expr_data(e);
switch (type) {
case NFTNL_OUTPUT_DEFAULT:
return snprintf(buf, len, "name %s rev %u ",
match->name, match->rev);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
static void nftnl_expr_match_free(const struct nftnl_expr *e)
{
struct nftnl_expr_match *match = nftnl_expr_data(e);
xfree(match->data);
}
struct expr_ops expr_ops_match = {
.name = "match",
.alloc_len = sizeof(struct nftnl_expr_match),
.max_attr = NFTA_MATCH_MAX,
.free = nftnl_expr_match_free,
.set = nftnl_expr_match_set,
.get = nftnl_expr_match_get,
.parse = nftnl_expr_match_parse,
.build = nftnl_expr_match_build,
.snprintf = nftnl_expr_match_snprintf,
};
nftnl_expr_match
Definition: match.c:30