path: root/src/expr/nat.c

/*
 * (C) 2012 Intel Corporation
 *
 * 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.
 *
 * Authors:
 * 	Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
 */

#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 <libnftables/expr.h>
#include <libnftables/rule.h>
#include "expr_ops.h"

struct nft_expr_nat {
	enum nft_registers sreg_addr_min;
	enum nft_registers sreg_addr_max;
	enum nft_registers sreg_proto_min;
	enum nft_registers sreg_proto_max;
	int                family;
	enum nft_nat_types type;
};

static int
nft_rule_expr_nat_set(struct nft_rule_expr *e, uint16_t type,
		      const void *data, uint32_t data_len)
{
	struct nft_expr_nat *nat = nft_expr_data(e);

	switch(type) {
	case NFT_EXPR_NAT_TYPE:
		nat->type = *((uint32_t *)data);
		break;
	case NFT_EXPR_NAT_FAMILY:
		nat->family = *((uint32_t *)data);
		break;
	case NFT_EXPR_NAT_REG_ADDR_MIN:
		nat->sreg_addr_min = *((uint32_t *)data);
		break;
	case NFT_EXPR_NAT_REG_ADDR_MAX:
		nat->sreg_addr_max = *((uint32_t *)data);
		break;
	case NFT_EXPR_NAT_REG_PROTO_MIN:
		nat->sreg_proto_min = *((uint32_t *)data);
		break;
	case NFT_EXPR_NAT_REG_PROTO_MAX:
		nat->sreg_proto_max = *((uint32_t *)data);
		break;
	default:
		return -1;
	}

	return 0;
}

static const void *
nft_rule_expr_nat_get(const struct nft_rule_expr *e, uint16_t type,
		      uint32_t *data_len)
{
	struct nft_expr_nat *nat = nft_expr_data(e);

	switch(type) {
	case NFT_EXPR_NAT_TYPE:
		*data_len = sizeof(nat->type);
		return &nat->type;
	case NFT_EXPR_NAT_FAMILY:
		*data_len = sizeof(nat->family);
		return &nat->family;
	case NFT_EXPR_NAT_REG_ADDR_MIN:
		*data_len = sizeof(nat->sreg_addr_min);
		return &nat->sreg_addr_min;
	case NFT_EXPR_NAT_REG_ADDR_MAX:
		*data_len = sizeof(nat->sreg_addr_max);
		return &nat->sreg_addr_max;
	case NFT_EXPR_NAT_REG_PROTO_MIN:
		*data_len = sizeof(nat->sreg_proto_min);
		return &nat->sreg_proto_min;
	case NFT_EXPR_NAT_REG_PROTO_MAX:
		*data_len = sizeof(nat->sreg_proto_max);
		return &nat->sreg_proto_max;
	}
	return NULL;
}

static int nft_rule_expr_nat_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_NAT_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_NAT_TYPE:
	case NFTA_NAT_FAMILY:
	case NFTA_NAT_REG_ADDR_MIN:
	case NFTA_NAT_REG_ADDR_MAX:
	case NFTA_NAT_REG_PROTO_MIN:
	case NFTA_NAT_REG_PROTO_MAX:
		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	}

	tb[type] = attr;
	return MNL_CB_OK;
}

static int
nft_rule_expr_nat_parse(struct nft_rule_expr *e, struct nlattr *attr)
{
	struct nft_expr_nat *nat = nft_expr_data(e);
	struct nlattr *tb[NFTA_NAT_MAX+1] = {};

	if (mnl_attr_parse_nested(attr, nft_rule_expr_nat_cb, tb) < 0)
		return -1;

	if (tb[NFTA_NAT_TYPE]) {
		nat->type = ntohl(mnl_attr_get_u32(tb[NFTA_NAT_TYPE]));
		e->flags |= (1 << NFT_EXPR_NAT_TYPE);
	}
	if (tb[NFTA_NAT_FAMILY]) {
		nat->family = ntohl(mnl_attr_get_u32(tb[NFTA_NAT_FAMILY]));
		e->flags |= (1 << NFT_EXPR_NAT_FAMILY);
	}
	if (tb[NFTA_NAT_REG_ADDR_MIN]) {
		nat->sreg_addr_min =
			ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_ADDR_MIN]));
		e->flags |= (1 << NFT_EXPR_NAT_REG_ADDR_MIN);
	}
	if (tb[NFTA_NAT_REG_ADDR_MAX]) {
		nat->sreg_addr_max =
			ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_ADDR_MAX]));
		e->flags |= (1 << NFT_EXPR_NAT_REG_ADDR_MAX);
	}
	if (tb[NFTA_NAT_REG_PROTO_MIN]) {
		nat->sreg_proto_min =
			ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_PROTO_MIN]));
		e->flags |= (1 << NFT_EXPR_NAT_REG_PROTO_MIN);
	}
	if (tb[NFTA_NAT_REG_PROTO_MAX]) {
		nat->sreg_proto_max =
			ntohl(mnl_attr_get_u32(tb[NFTA_NAT_REG_PROTO_MAX]));
		e->flags |= (1 << NFT_EXPR_NAT_REG_PROTO_MAX);
	}

	return 0;
}

static void
nft_rule_expr_nat_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
{
	struct nft_expr_nat *nat = nft_expr_data(e);

	if (e->flags & (1 << NFT_EXPR_NAT_TYPE))
		mnl_attr_put_u32(nlh, NFTA_NAT_TYPE, htonl(nat->type));
	if (e->flags & (1 << NFT_EXPR_NAT_FAMILY))
		mnl_attr_put_u32(nlh, NFTA_NAT_FAMILY, htonl(nat->family));
	if (e->flags & (1 << NFT_EXPR_NAT_REG_ADDR_MIN))
		mnl_attr_put_u32(nlh, NFTA_NAT_REG_ADDR_MIN,
				 htonl(nat->sreg_addr_min));
	if (e->flags & (1 << NFT_EXPR_NAT_REG_ADDR_MAX))
		mnl_attr_put_u32(nlh, NFTA_NAT_REG_ADDR_MAX,
				 htonl(nat->sreg_addr_max));
	if (e->flags & (1 << NFT_EXPR_NAT_REG_PROTO_MIN))
		mnl_attr_put_u32(nlh, NFTA_NAT_REG_PROTO_MIN,
				 htonl(nat->sreg_proto_min));
	if (e->flags & (1 << NFT_EXPR_NAT_REG_PROTO_MAX))
		mnl_attr_put_u32(nlh, NFTA_NAT_REG_PROTO_MAX,
				 htonl(nat->sreg_proto_max));
}

static inline int nft_str2nat(const char *nat)
{
	if (strcmp(nat, "snat") == 0)
		return NFT_NAT_SNAT;
	else if (strcmp(nat, "dnat") == 0)
		return NFT_NAT_DNAT;
	else {
		errno = EINVAL;
		return -1;
	}
}

static int nft_rule_expr_nat_json_parse(struct nft_rule_expr *e, json_t *root,
					struct nft_parse_err *err)
{
#ifdef JSON_PARSING
	const char *nat_type, *family_str;
	uint32_t reg;
	int val32;

	nat_type = nft_jansson_parse_str(root, "nat_type", err);
	if (nat_type == NULL)
		return -1;

	val32 = nft_str2nat(nat_type);
	if (val32 < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_TYPE, val32);

	family_str = nft_jansson_parse_str(root, "family", err);
	if (family_str == NULL)
		return -1;

	val32 = nft_str2family(family_str);
	if (val32 < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_FAMILY, val32);

	if (nft_jansson_parse_reg(root, "sreg_addr_min", NFT_TYPE_U32,
				  &reg, err) < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_REG_ADDR_MIN, reg);

	if (nft_jansson_parse_reg(root, "sreg_addr_max", NFT_TYPE_U32,
				  &reg, err) < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_REG_ADDR_MAX, reg);

	if (nft_jansson_parse_reg(root, "sreg_proto_min", NFT_TYPE_U32,
				  &reg, err) < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_REG_PROTO_MIN, reg);

	if (nft_jansson_parse_reg(root, "sreg_proto_max", NFT_TYPE_U32,
				  &reg, err) < 0)
		return -1;

	nft_rule_expr_set_u32(e, NFT_EXPR_NAT_REG_PROTO_MAX, reg);

	return 0;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

static int nft_rule_expr_nat_xml_parse(struct nft_rule_expr *e, mxml_node_t *tree,
				       struct nft_parse_err *err)
{
#ifdef XML_PARSING
	struct nft_expr_nat *nat = nft_expr_data(e);
	const char *nat_type;
	int family, nat_type_value;
	uint32_t reg;

	nat_type = nft_mxml_str_parse(tree, "type", MXML_DESCEND_FIRST,
				      NFT_XML_MAND, err);
	if (nat_type == NULL)
		return -1;

	nat_type_value = nft_str2nat(nat_type);
	if (nat_type_value < 0)
		return -1;

	nat->type = nat_type_value;
	e->flags |= (1 << NFT_EXPR_NAT_TYPE);

	family = nft_mxml_family_parse(tree, "family", MXML_DESCEND_FIRST,
				       NFT_XML_MAND, err);
	if (family < 0) {
		mxmlDelete(tree);
		return -1;
	}

	nat->family = family;
	e->flags |= (1 << NFT_EXPR_NAT_FAMILY);

	if (nft_mxml_reg_parse(tree, "sreg_addr_min", &reg,
			       MXML_DESCEND, NFT_XML_MAND, err) != 0)
		return -1;

	nat->sreg_addr_min = reg;
	e->flags |= (1 << NFT_EXPR_NAT_REG_ADDR_MIN);

	if (nft_mxml_reg_parse(tree, "sreg_addr_max", &reg,
			       MXML_DESCEND, NFT_XML_MAND, err) != 0)
		return -1;

	nat->sreg_addr_max = reg;
	e->flags |= (1 << NFT_EXPR_NAT_REG_ADDR_MAX);

	if (nft_mxml_reg_parse(tree, "sreg_proto_min", &reg,
			       MXML_DESCEND, NFT_XML_MAND, err) != 0)
		return -1;

	nat->sreg_proto_min = reg;
	e->flags |= (1 << NFT_EXPR_NAT_REG_PROTO_MIN);

	if (nft_mxml_reg_parse(tree, "sreg_proto_max", &reg,
			       MXML_DESCEND, NFT_XML_MAND, err) != 0)
		return -1;

	nat->sreg_proto_max = reg;
	e->flags |= (1 << NFT_EXPR_NAT_REG_PROTO_MAX);

	return 0;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

static int
nft_rule_expr_nat_snprintf_json(char *buf, size_t size,
				struct nft_rule_expr *e)
{
	struct nft_expr_nat *nat = nft_expr_data(e);
	int len = size, offset = 0, ret = 0;

	if (nat->type == NFT_NAT_SNAT)
		ret = snprintf(buf, len, "\"nat_type\":\"snat\",");
	else if (nat->type == NFT_NAT_DNAT)
		ret = snprintf(buf, len, "\"nat_type\":\"dnat\",");

	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = snprintf(buf+offset, len, "\"family\":\"%s\",",
		       nft_family2str(nat->family));
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	if (e->flags & (1 << NFT_EXPR_NAT_REG_ADDR_MIN)) {
		ret = snprintf(buf+offset, len, "\"sreg_addr_min\":%u,"
						"\"sreg_addr_max\":%u,",
			       nat->sreg_addr_min, nat->sreg_addr_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	if (e->flags & (1 << NFT_EXPR_NAT_REG_PROTO_MIN)) {
		ret = snprintf(buf+offset, len, "\"sreg_proto_min\":%u,"
						"\"sreg_proto_max\":%u",
		       nat->sreg_proto_min, nat->sreg_proto_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	return offset;
}


static int
nft_rule_expr_nat_snprintf_xml(char *buf, size_t size,
				struct nft_rule_expr *e)
{
	struct nft_expr_nat *nat = nft_expr_data(e);
	int len = size, offset = 0, ret = 0;

	/* Is a mandatory element. Provide a default, even empty */
	if (nat->type == NFT_NAT_SNAT)
		ret = snprintf(buf, len, "<type>snat</type>");
	else if (nat->type == NFT_NAT_DNAT)
		ret = snprintf(buf, len, "<type>dnat</type>");
	else
		ret = snprintf(buf, len, "<type>unknown</type>");

	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	ret = snprintf(buf+offset, len, "<family>%s</family>",
		       nft_family2str(nat->family));
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	if (e->flags & (1 << NFT_EXPR_NAT_REG_ADDR_MIN)) {
		ret = snprintf(buf+offset, len,
				"<sreg_addr_min>%u</sreg_addr_min>"
				"<sreg_addr_max>%u</sreg_addr_max>",
			       nat->sreg_addr_min, nat->sreg_addr_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	if (e->flags & (1 << NFT_EXPR_NAT_REG_PROTO_MIN)) {
		ret = snprintf(buf+offset, len,
				"<sreg_proto_min>%u</sreg_proto_min>"
				"<sreg_proto_max>%u</sreg_proto_max>",
		       nat->sreg_proto_min, nat->sreg_proto_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	return offset;
}

static int
nft_rule_expr_nat_snprintf_default(char *buf, size_t size,
				   struct nft_rule_expr *e)
{
	struct nft_expr_nat *nat = nft_expr_data(e);
	int len = size, offset = 0, ret = 0;

	switch (nat->type) {
	case NFT_NAT_SNAT:
		ret = snprintf(buf, len, "snat ");
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
		break;
	case NFT_NAT_DNAT:
		ret = snprintf(buf, len, "dnat ");
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
		break;
	}

	ret = snprintf(buf+offset, len, "%s ", nft_family2str(nat->family));
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	if (e->flags & (1 << NFT_EXPR_NAT_REG_ADDR_MIN)) {
		ret = snprintf(buf+offset, len,
			       "addr_min reg %u addr_max reg %u ",
			       nat->sreg_addr_min, nat->sreg_addr_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	if (e->flags & (1 << NFT_EXPR_NAT_REG_PROTO_MIN)) {
		ret = snprintf(buf+offset, len,
			       "proto_min reg %u proto_max reg %u ",
			       nat->sreg_proto_min, nat->sreg_proto_max);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	return offset;
}

static int
nft_rule_expr_nat_snprintf(char *buf, size_t size, uint32_t type,
			   uint32_t flags, struct nft_rule_expr *e)
{
	switch (type) {
	case NFT_OUTPUT_DEFAULT:
		return nft_rule_expr_nat_snprintf_default(buf, size, e);
	case NFT_OUTPUT_XML:
		return nft_rule_expr_nat_snprintf_xml(buf, size, e);
	case NFT_OUTPUT_JSON:
		return nft_rule_expr_nat_snprintf_json(buf, size, e);
	default:
		break;
	}
	return -1;
}

struct expr_ops expr_ops_nat = {
	.name		= "nat",
	.alloc_len	= sizeof(struct nft_expr_nat),
	.max_attr	= NFTA_NAT_MAX,
	.set		= nft_rule_expr_nat_set,
	.get		= nft_rule_expr_nat_get,
	.parse		= nft_rule_expr_nat_parse,
	.build		= nft_rule_expr_nat_build,
	.snprintf	= nft_rule_expr_nat_snprintf,
	.xml_parse	= nft_rule_expr_nat_xml_parse,
	.json_parse	= nft_rule_expr_nat_json_parse,
};

static void __init expr_nat_init(void)
{
	nft_expr_ops_register(&expr_ops_nat);
}