tproxy.c
/*
* Copyright (c) 2018 Máté Eckl <ecklm94@gmail.com>
*
* 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.
*/
#include "internal.h"
#include <stdio.h>
#include <stdint.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nf_tables.h>
#include <libnftnl/expr.h>
#include <libnftnl/rule.h>
struct nftnl_expr_tproxy {
enum nft_registers sreg_addr;
enum nft_registers sreg_port;
int family;
};
static int
nftnl_expr_tproxy_set(struct nftnl_expr *e, uint16_t type,
const void *data, uint32_t data_len)
{
struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_TPROXY_FAMILY:
memcpy(&tproxy->family, data, sizeof(tproxy->family));
break;
case NFTNL_EXPR_TPROXY_REG_ADDR:
memcpy(&tproxy->sreg_addr, data, sizeof(tproxy->sreg_addr));
break;
case NFTNL_EXPR_TPROXY_REG_PORT:
memcpy(&tproxy->sreg_port, data, sizeof(tproxy->sreg_port));
break;
default:
return -1;
}
return 0;
}
static const void *
nftnl_expr_tproxy_get(const struct nftnl_expr *e, uint16_t type,
uint32_t *data_len)
{
struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
switch(type) {
case NFTNL_EXPR_TPROXY_FAMILY:
*data_len = sizeof(tproxy->family);
return &tproxy->family;
case NFTNL_EXPR_TPROXY_REG_ADDR:
*data_len = sizeof(tproxy->sreg_addr);
return &tproxy->sreg_addr;
case NFTNL_EXPR_TPROXY_REG_PORT:
*data_len = sizeof(tproxy->sreg_port);
return &tproxy->sreg_port;
}
return NULL;
}
static int nftnl_expr_tproxy_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_TPROXY_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case NFTA_TPROXY_FAMILY:
case NFTA_TPROXY_REG_ADDR:
case NFTA_TPROXY_REG_PORT:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
abi_breakage();
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static int
nftnl_expr_tproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
{
struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
struct nlattr *tb[NFTA_TPROXY_MAX + 1] = {};
if (mnl_attr_parse_nested(attr, nftnl_expr_tproxy_cb, tb) < 0)
return -1;
if (tb[NFTA_TPROXY_FAMILY]) {
tproxy->family = ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_FAMILY]));
e->flags |= (1 << NFTNL_EXPR_TPROXY_FAMILY);
}
if (tb[NFTA_TPROXY_REG_ADDR]) {
tproxy->sreg_addr =
ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_ADDR]));
e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_ADDR);
}
if (tb[NFTA_TPROXY_REG_PORT]) {
tproxy->sreg_port =
ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_PORT]));
e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_PORT);
}
return 0;
}
static void
nftnl_expr_tproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
{
struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
if (e->flags & (1 << NFTNL_EXPR_TPROXY_FAMILY))
mnl_attr_put_u32(nlh, NFTA_TPROXY_FAMILY, htonl(tproxy->family));
if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR))
mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_ADDR,
htonl(tproxy->sreg_addr));
if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT))
mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_PORT,
htonl(tproxy->sreg_port));
}
static int
nftnl_expr_tproxy_snprintf_default(char *buf, size_t size,
const struct nftnl_expr *e)
{
struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
int remain = size, offset = 0, ret = 0;
if (tproxy->family != NFTA_TPROXY_UNSPEC) {
ret = snprintf(buf + offset, remain, "%s ",
nftnl_family2str(tproxy->family));
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
}
if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR)) {
ret = snprintf(buf + offset, remain,
"addr reg %u ", tproxy->sreg_addr);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
}
if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT)) {
ret = snprintf(buf + offset, remain,
"port reg %u ", tproxy->sreg_port);
SNPRINTF_BUFFER_SIZE(ret, remain, offset);
}
return offset;
}
static int
nftnl_expr_tproxy_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_tproxy_snprintf_default(buf, size, e);
default:
break;
}
return -1;
}
struct expr_ops expr_ops_tproxy = {
.name = "tproxy",
.alloc_len = sizeof(struct nftnl_expr_tproxy),
.max_attr = NFTA_TPROXY_MAX,
.set = nftnl_expr_tproxy_set,
.get = nftnl_expr_tproxy_get,
.parse = nftnl_expr_tproxy_parse,
.build = nftnl_expr_tproxy_build,
.snprintf = nftnl_expr_tproxy_snprintf,
};
nftnl_expr_tproxy
Definition: tproxy.c:23