cmp.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>
#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_cmp {
union nftnl_data_reg data;
enum nft_registers sreg;
enum nft_cmp_ops op;
};
static int
nftnl_expr_cmp_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_cmp *cmp = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_CMP_SREG:
memcpy(&cmp->sreg, data, sizeof(cmp->sreg));
break;
case NFTNL_EXPR_CMP_OP:
memcpy(&cmp->op, data, sizeof(cmp->op));
break;
case NFTNL_EXPR_CMP_DATA:
memcpy(&cmp->data.val, data, data_len);
cmp->data.len = data_len;
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_cmp_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_cmp *cmp = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_CMP_SREG:
*data_len = sizeof(cmp->sreg);
return &cmp->sreg;
case NFTNL_EXPR_CMP_OP:
*data_len = sizeof(cmp->op);
return &cmp->op;
case NFTNL_EXPR_CMP_DATA:
*data_len = cmp->data.len;
return &cmp->data.val;
}
return NULL;
}
static int nftnl_expr_cmp_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_CMP_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_CMP_SREG:
case NFTA_CMP_OP:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
case NFTA_CMP_DATA:
if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void
nftnl_expr_cmp_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_cmp *cmp = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_CMP_SREG))
mnl_attr_put_u32(nlh, NFTA_CMP_SREG, htonl(cmp->sreg));
if (e->flags & (1 << NFTNL_EXPR_CMP_OP))
mnl_attr_put_u32(nlh, NFTA_CMP_OP, htonl(cmp->op));
if (e->flags & (1 << NFTNL_EXPR_CMP_DATA)) {
struct nlattr *nest;
nest = mnl_attr_nest_start(nlh, NFTA_CMP_DATA);
mnl_attr_put(nlh, NFTA_DATA_VALUE, cmp->data.len, cmp->data.val);
mnl_attr_nest_end(nlh, nest);
}
}
static int
nftnl_expr_cmp_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_cmp *cmp = nftnl_expr_data(e);
struct nlattr *tb[NFTA_CMP_MAX+1] = {};
int ret = 0;
if (mnl_attr_parse_nested(attr, nftnl_expr_cmp_cb, tb) < 0)
return -1;
if (tb[NFTA_CMP_SREG]) {
cmp->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_SREG]));
e->flags |= (1 << NFTA_CMP_SREG);
}
if (tb[NFTA_CMP_OP]) {
cmp->op = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_OP]));
e->flags |= (1 << NFTA_CMP_OP);
}
if (tb[NFTA_CMP_DATA]) {
ret = nftnl_parse_data(&cmp->data, tb[NFTA_CMP_DATA], NULL);
e->flags |= (1 << NFTA_CMP_DATA);
}
return ret;
}
static const char *expr_cmp_str[] = {
[NFT_CMP_EQ] = "eq",
[NFT_CMP_NEQ] = "neq",
[NFT_CMP_LT] = "lt",
[NFT_CMP_LTE] = "lte",
[NFT_CMP_GT] = "gt",
[NFT_CMP_GTE] = "gte",
};
static const char *cmp2str(uint32_t op)
{
if (op > NFT_CMP_GTE)
return "unknown";
return expr_cmp_str[op];
}
static inline int nftnl_str2cmp(const char *op)
{
if (strcmp(op, "eq") == 0)
return NFT_CMP_EQ;
else if (strcmp(op, "neq") == 0)
return NFT_CMP_NEQ;
else if (strcmp(op, "lt") == 0)
return NFT_CMP_LT;
else if (strcmp(op, "lte") == 0)
return NFT_CMP_LTE;
else if (strcmp(op, "gt") == 0)
return NFT_CMP_GT;
else if (strcmp(op, "gte") == 0)
return NFT_CMP_GTE;
else {
errno = EINVAL;
return -1;
}
}
static int nftnl_expr_cmp_snprintf_default(char *buf, size_t size,
const struct nftnl_expr *e)
{
struct nftnl_expr_cmp *cmp = nftnl_expr_data(e);
int remain = size, offset = 0, ret;
ret = snprintf(buf, remain, "%s reg %u ",
cmp2str(cmp->op), cmp->sreg);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
ret = nftnl_data_reg_snprintf(buf + offset, remain, &cmp->data,
NFTNL_OUTPUT_DEFAULT, 0, DATA_VALUE);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
return offset;
}
static int
nftnl_expr_cmp_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_cmp_snprintf_default(buf, size, e);
case NFTNL_OUTPUT_XML:
case NFTNL_OUTPUT_JSON:
default:
break;
}
return -1;
}
struct expr_ops expr_ops_cmp = {
.name = "cmp",
.alloc_len = sizeof(struct nftnl_expr_cmp),
.max_attr = NFTA_CMP_MAX,
.set = nftnl_expr_cmp_set,
.get = nftnl_expr_cmp_get,
.parse = nftnl_expr_cmp_parse,
.build = nftnl_expr_cmp_build,
.snprintf = nftnl_expr_cmp_snprintf,
};
nftnl_expr_cmp
Definition: cmp.c:25