path: root/src/chain.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 <time.h>
#include <endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <netinet/in.h>
#include <errno.h>
#include <inttypes.h>

#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <linux/netfilter.h>

#include <libnftables/chain.h>

struct nft_chain {
	struct list_head head;

	char		name[NFT_CHAIN_MAXNAMELEN];
	const char	*type;
	const char	*table;
	uint8_t		family;
	uint32_t	policy;
	uint32_t	hooknum;
	int32_t		prio;
	uint32_t	use;
	uint64_t	packets;
	uint64_t	bytes;
	uint64_t	handle;
	uint32_t	flags;
};

static const char *hooknum2str_array[NF_INET_NUMHOOKS] = {
	[NF_INET_PRE_ROUTING]	= "NF_INET_PRE_ROUTING",
	[NF_INET_LOCAL_IN]	= "NF_INET_LOCAL_IN",
	[NF_INET_FORWARD]	= "NF_INET_FORWARD",
	[NF_INET_LOCAL_OUT]	= "NF_INET_LOCAL_OUT",
	[NF_INET_POST_ROUTING]	= "NF_INET_POST_ROUTING",
};

struct nft_chain *nft_chain_alloc(void)
{
	return calloc(1, sizeof(struct nft_chain));
}
EXPORT_SYMBOL(nft_chain_alloc);

void nft_chain_free(struct nft_chain *c)
{
	if (c->table != NULL)
		xfree(c->table);
	if (c->type != NULL)
		xfree(c->type);

	xfree(c);
}
EXPORT_SYMBOL(nft_chain_free);

bool nft_chain_attr_is_set(const struct nft_chain *c, uint16_t attr)
{
	return c->flags & (1 << attr);
}
EXPORT_SYMBOL(nft_chain_attr_is_set);

void nft_chain_attr_unset(struct nft_chain *c, uint16_t attr)
{
	if (!(c->flags & (1 << attr)))
		return;

	switch (attr) {
	case NFT_CHAIN_ATTR_TABLE:
		if (c->table) {
			xfree(c->table);
			c->table = NULL;
		}
		break;
	case NFT_CHAIN_ATTR_USE:
		/* cannot be unset?, ignore it */
		return;
	case NFT_CHAIN_ATTR_TYPE:
		if (c->type) {
			xfree(c->type);
			c->type = NULL;
		}
		break;
	case NFT_CHAIN_ATTR_NAME:
	case NFT_CHAIN_ATTR_HOOKNUM:
	case NFT_CHAIN_ATTR_PRIO:
	case NFT_CHAIN_ATTR_POLICY:
	case NFT_CHAIN_ATTR_BYTES:
	case NFT_CHAIN_ATTR_PACKETS:
	case NFT_CHAIN_ATTR_HANDLE:
	case NFT_CHAIN_ATTR_FAMILY:
		break;
	default:
		return;
	}

	c->flags &= ~(1 << attr);
}
EXPORT_SYMBOL(nft_chain_attr_unset);

void nft_chain_attr_set(struct nft_chain *c, uint16_t attr, const void *data)
{
	switch(attr) {
	case NFT_CHAIN_ATTR_NAME:
		strncpy(c->name, data, NFT_CHAIN_MAXNAMELEN);
		break;
	case NFT_CHAIN_ATTR_TABLE:
		if (c->table)
			xfree(c->table);

		c->table = strdup(data);
		break;
	case NFT_CHAIN_ATTR_HOOKNUM:
		memcpy(&c->hooknum, data, sizeof(c->hooknum));
		break;
	case NFT_CHAIN_ATTR_PRIO:
		memcpy(&c->prio, data, sizeof(c->prio));
		break;
	case NFT_CHAIN_ATTR_POLICY:
		c->policy = *((uint32_t *)data);
		break;
	case NFT_CHAIN_ATTR_USE:
		/* cannot be set, ignore it */
		return;
	case NFT_CHAIN_ATTR_BYTES:
		c->bytes = *((uint64_t *)data);
		break;
	case NFT_CHAIN_ATTR_PACKETS:
		c->packets = *((uint64_t *)data);
		break;
	case NFT_CHAIN_ATTR_HANDLE:
		c->handle = *((uint64_t *)data);
		break;
	case NFT_CHAIN_ATTR_FAMILY:
		c->family = *((uint8_t *)data);
		break;
	case NFT_CHAIN_ATTR_TYPE:
		if (c->type)
			xfree(c->type);

		c->type = strdup(data);
		break;
	default:
		return;
	}
	c->flags |= (1 << attr);
}
EXPORT_SYMBOL(nft_chain_attr_set);

void nft_chain_attr_set_u32(struct nft_chain *c, uint16_t attr, uint32_t data)
{
	nft_chain_attr_set(c, attr, &data);
}
EXPORT_SYMBOL(nft_chain_attr_set_u32);

void nft_chain_attr_set_s32(struct nft_chain *c, uint16_t attr, int32_t data)
{
	nft_chain_attr_set(c, attr, &data);
}
EXPORT_SYMBOL(nft_chain_attr_set_s32);

void nft_chain_attr_set_u64(struct nft_chain *c, uint16_t attr, uint64_t data)
{
	nft_chain_attr_set(c, attr, &data);
}
EXPORT_SYMBOL(nft_chain_attr_set_u64);

void nft_chain_attr_set_str(struct nft_chain *c, uint16_t attr, const char *str)
{
	nft_chain_attr_set(c, attr, str);
}
EXPORT_SYMBOL(nft_chain_attr_set_str);

const void *nft_chain_attr_get(struct nft_chain *c, uint16_t attr)
{
	if (!(c->flags & (1 << attr)))
		return NULL;

	switch(attr) {
	case NFT_CHAIN_ATTR_NAME:
		return c->name;
	case NFT_CHAIN_ATTR_TABLE:
		return c->table;
	case NFT_CHAIN_ATTR_HOOKNUM:
		return &c->hooknum;
	case NFT_CHAIN_ATTR_PRIO:
		return &c->prio;
	case NFT_CHAIN_ATTR_POLICY:
		return &c->policy;
	case NFT_CHAIN_ATTR_USE:
		return &c->use;
	case NFT_CHAIN_ATTR_BYTES:
		return &c->bytes;
	case NFT_CHAIN_ATTR_PACKETS:
		return &c->packets;
	case NFT_CHAIN_ATTR_HANDLE:
		return &c->handle;
	case NFT_CHAIN_ATTR_FAMILY:
		return &c->family;
	case NFT_CHAIN_ATTR_TYPE:
		return c->type;
	}
	return NULL;
}
EXPORT_SYMBOL(nft_chain_attr_get);

const char *nft_chain_attr_get_str(struct nft_chain *c, uint16_t attr)
{
	return nft_chain_attr_get(c, attr);
}
EXPORT_SYMBOL(nft_chain_attr_get_str);

uint32_t nft_chain_attr_get_u32(struct nft_chain *c, uint16_t attr)
{
	const uint32_t *val = nft_chain_attr_get(c, attr);
	return val ? *val : 0;
}
EXPORT_SYMBOL(nft_chain_attr_get_u32);

int32_t nft_chain_attr_get_s32(struct nft_chain *c, uint16_t attr)
{
	const int32_t *val = nft_chain_attr_get(c, attr);
	return val ? *val : 0;
}
EXPORT_SYMBOL(nft_chain_attr_get_s32);

uint64_t nft_chain_attr_get_u64(struct nft_chain *c, uint16_t attr)
{
	const uint64_t *val = nft_chain_attr_get(c, attr);
	return val ? *val : 0;
}
EXPORT_SYMBOL(nft_chain_attr_get_u64);

struct nlmsghdr *
nft_chain_nlmsg_build_hdr(char *buf, uint16_t cmd, uint16_t family,
			  uint16_t type, uint32_t seq)
{
	struct nlmsghdr *nlh;
	struct nfgenmsg *nfh;

	nlh = mnl_nlmsg_put_header(buf);
	nlh->nlmsg_type = (NFNL_SUBSYS_NFTABLES << 8) | cmd;
	nlh->nlmsg_flags = NLM_F_REQUEST | type;
	nlh->nlmsg_seq = seq;

	nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
	nfh->nfgen_family = family;
	nfh->version = NFNETLINK_V0;
	nfh->res_id = 0;

	return nlh;
}
EXPORT_SYMBOL(nft_chain_nlmsg_build_hdr);

void nft_chain_nlmsg_build_payload(struct nlmsghdr *nlh, const struct nft_chain *c)
{
	if (c->flags & (1 << NFT_CHAIN_ATTR_TABLE))
		mnl_attr_put_strz(nlh, NFTA_CHAIN_TABLE, c->table);
	if (c->flags & (1 << NFT_CHAIN_ATTR_NAME))
		mnl_attr_put_strz(nlh, NFTA_CHAIN_NAME, c->name);
	if ((c->flags & (1 << NFT_CHAIN_ATTR_HOOKNUM)) &&
	    (c->flags & (1 << NFT_CHAIN_ATTR_PRIO))) {
		struct nlattr *nest;

		nest = mnl_attr_nest_start(nlh, NFTA_CHAIN_HOOK);
		mnl_attr_put_u32(nlh, NFTA_HOOK_HOOKNUM, htonl(c->hooknum));
		mnl_attr_put_u32(nlh, NFTA_HOOK_PRIORITY, htonl(c->prio));
		mnl_attr_nest_end(nlh, nest);
	}
	if (c->flags & (1 << NFT_CHAIN_ATTR_POLICY))
		mnl_attr_put_u32(nlh, NFTA_CHAIN_POLICY, htonl(c->policy));
	if ((c->flags & (1 << NFT_CHAIN_ATTR_PACKETS)) &&
	    (c->flags & (1 << NFT_CHAIN_ATTR_BYTES))) {
		struct nlattr *nest;

		nest = mnl_attr_nest_start(nlh, NFTA_CHAIN_COUNTERS);
		mnl_attr_put_u64(nlh, NFTA_COUNTER_PACKETS, be64toh(c->packets));
		mnl_attr_put_u64(nlh, NFTA_COUNTER_BYTES, be64toh(c->bytes));
		mnl_attr_nest_end(nlh, nest);
	}
	if (c->flags & (1 << NFT_CHAIN_ATTR_HANDLE))
		mnl_attr_put_u64(nlh, NFTA_CHAIN_HANDLE, be64toh(c->handle));
	if (c->flags & (1 << NFT_CHAIN_ATTR_TYPE))
		mnl_attr_put_strz(nlh, NFTA_CHAIN_TYPE, c->type);
}
EXPORT_SYMBOL(nft_chain_nlmsg_build_payload);

static int nft_chain_parse_attr_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_CHAIN_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_CHAIN_NAME:
	case NFTA_CHAIN_TABLE:
	case NFTA_CHAIN_TYPE:
		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	case NFTA_CHAIN_HOOK:
	case NFTA_CHAIN_COUNTERS:
		if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	case NFTA_CHAIN_POLICY:
	case NFTA_CHAIN_USE:
		if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	case NFTA_CHAIN_HANDLE:
		if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	}

	tb[type] = attr;
	return MNL_CB_OK;
}

static int nft_chain_parse_counters_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_COUNTER_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_COUNTER_BYTES:
	case NFTA_COUNTER_PACKETS:
		if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
			perror("mnl_attr_validate");
			return MNL_CB_ERROR;
		}
		break;
	}

	tb[type] = attr;
	return MNL_CB_OK;
}

static int nft_chain_parse_counters(struct nlattr *attr, struct nft_chain *c)
{
	struct nlattr *tb[NFTA_COUNTER_MAX+1] = {};

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

	if (tb[NFTA_COUNTER_PACKETS]) {
		c->packets = be64toh(mnl_attr_get_u64(tb[NFTA_COUNTER_PACKETS]));
		c->flags |= (1 << NFT_CHAIN_ATTR_PACKETS);
	}
	if (tb[NFTA_COUNTER_BYTES]) {
		c->bytes = be64toh(mnl_attr_get_u64(tb[NFTA_COUNTER_BYTES]));
		c->flags |= (1 << NFT_CHAIN_ATTR_BYTES);
	}

	return 0;
}
static int nft_chain_parse_hook_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_HOOK_MAX) < 0)
		return MNL_CB_OK;

	switch(type) {
	case NFTA_HOOK_HOOKNUM:
	case NFTA_HOOK_PRIORITY:
		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_chain_parse_hook(struct nlattr *attr, struct nft_chain *c)
{
	struct nlattr *tb[NFTA_HOOK_MAX+1] = {};

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

	if (tb[NFTA_HOOK_HOOKNUM]) {
		c->hooknum = ntohl(mnl_attr_get_u32(tb[NFTA_HOOK_HOOKNUM]));
		c->flags |= (1 << NFT_CHAIN_ATTR_HOOKNUM);
	}
	if (tb[NFTA_HOOK_PRIORITY]) {
		c->prio = ntohl(mnl_attr_get_u32(tb[NFTA_HOOK_PRIORITY]));
		c->flags |= (1 << NFT_CHAIN_ATTR_PRIO);
	}

	return 0;
}

int nft_chain_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_chain *c)
{
	struct nlattr *tb[NFTA_CHAIN_MAX+1] = {};
	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
	int ret = 0;

	mnl_attr_parse(nlh, sizeof(*nfg), nft_chain_parse_attr_cb, tb);
	if (tb[NFTA_CHAIN_NAME]) {
		strncpy(c->name, mnl_attr_get_str(tb[NFTA_CHAIN_NAME]),
			NFT_CHAIN_MAXNAMELEN);
		c->flags |= (1 << NFT_CHAIN_ATTR_NAME);
	}
	if (tb[NFTA_CHAIN_TABLE]) {
		c->table = strdup(mnl_attr_get_str(tb[NFTA_CHAIN_TABLE]));
		c->flags |= (1 << NFT_CHAIN_ATTR_TABLE);
	}
	if (tb[NFTA_CHAIN_HOOK])
		ret = nft_chain_parse_hook(tb[NFTA_CHAIN_HOOK], c);
	if (tb[NFTA_CHAIN_POLICY]) {
		c->policy = ntohl(mnl_attr_get_u32(tb[NFTA_CHAIN_POLICY]));
		c->flags |= (1 << NFT_CHAIN_ATTR_POLICY);
	}
	if (tb[NFTA_CHAIN_USE]) {
		c->use = ntohl(mnl_attr_get_u32(tb[NFTA_CHAIN_USE]));
		c->flags |= (1 << NFT_CHAIN_ATTR_USE);
	}
	if (tb[NFTA_CHAIN_COUNTERS])
		ret = nft_chain_parse_counters(tb[NFTA_CHAIN_COUNTERS], c);
	if (tb[NFTA_CHAIN_HANDLE]) {
		c->handle = be64toh(mnl_attr_get_u64(tb[NFTA_CHAIN_HANDLE]));
		c->flags |= (1 << NFT_CHAIN_ATTR_HANDLE);
	}
	if (tb[NFTA_CHAIN_TYPE]) {
		c->type = strdup(mnl_attr_get_str(tb[NFTA_CHAIN_TYPE]));
		c->flags |= (1 << NFT_CHAIN_ATTR_TYPE);
	}

	c->family = nfg->nfgen_family;
	c->flags |= (1 << NFT_CHAIN_ATTR_FAMILY);

	return ret;
}
EXPORT_SYMBOL(nft_chain_nlmsg_parse);

static inline int nft_str2hooknum(const char *hook)
{
	int hooknum;

	for (hooknum = 0; hooknum < NF_INET_NUMHOOKS; hooknum++) {
		if (strcmp(hook, hooknum2str_array[hooknum]) == 0)
			return hooknum;
	}
	return -1;
}

static int nft_chain_json_parse(struct nft_chain *c, const char *json)
{
#ifdef JSON_PARSING
	json_t *root, *node;
	json_error_t error;
	uint64_t uval64;
	uint32_t policy;
	int32_t val32;
	const char *valstr;

	node = nft_jansson_create_root(json, &error);
	if (node == NULL)
		return -1;

	root = nft_jansson_get_node(node, "chain");
	if (root == NULL)
		return -1;

	valstr = nft_jansson_parse_str(root, "name");
	if (valstr == NULL)
		goto err;

	nft_chain_attr_set_str(c, NFT_CHAIN_ATTR_NAME, valstr);

	if (nft_jansson_parse_val(root, "handle", NFT_TYPE_U64, &uval64) < 0)
		goto err;

	nft_chain_attr_set_u64(c,NFT_CHAIN_ATTR_HANDLE, uval64);

	if (nft_jansson_parse_val(root, "bytes", NFT_TYPE_U64, &uval64) < 0)
		goto err;

	nft_chain_attr_set_u64(c, NFT_CHAIN_ATTR_BYTES, uval64);

	if (nft_jansson_parse_val(root, "packets", NFT_TYPE_U64, &uval64) < 0)
		goto err;

	nft_chain_attr_set_u64(c, NFT_CHAIN_ATTR_PACKETS, uval64);

	if (nft_jansson_parse_family(root, &val32) != 0)
		goto err;

	nft_chain_attr_set_u32(c, NFT_CHAIN_ATTR_FAMILY, val32);

	valstr = nft_jansson_parse_str(root, "table");

	if (valstr == NULL)
		goto err;

	nft_chain_attr_set_str(c, NFT_CHAIN_ATTR_TABLE, valstr);

	if (nft_jansson_node_exist(root, "hooknum")) {
		valstr = nft_jansson_parse_str(root, "type");

		if (valstr == NULL)
			goto err;

		nft_chain_attr_set_str(c, NFT_CHAIN_ATTR_TYPE, valstr);

		if (nft_jansson_parse_val(root, "prio", NFT_TYPE_S32,
					  &val32) < 0)
			goto err;

		nft_chain_attr_set_s32(c, NFT_CHAIN_ATTR_PRIO, val32);

		valstr = nft_jansson_parse_str(root, "hooknum");
		if (valstr == NULL)
			goto err;

		val32 = nft_str2hooknum(valstr);
		if (val32 == -1)
			goto err;

		nft_chain_attr_set_u32(c, NFT_CHAIN_ATTR_HOOKNUM, val32);

		valstr = nft_jansson_parse_str(root, "policy");
		if (valstr == NULL)
			goto err;

		policy = nft_str2verdict(valstr);
		if (policy == -1)
			goto err;

		nft_chain_attr_set_u32(c, NFT_CHAIN_ATTR_POLICY, policy);
	}

	nft_jansson_free_root(node);
	return 0;

err:
	nft_jansson_free_root(node);
	return -1;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

static int nft_chain_xml_parse(struct nft_chain *c, const char *xml)
{
#ifdef XML_PARSING
	mxml_node_t *tree;
	const char *table, *name, *hooknum_str, *policy_str, *type;
	int family, hooknum, policy;

	tree = mxmlLoadString(NULL, xml, MXML_OPAQUE_CALLBACK);
	if (tree == NULL)
		return -1;

	if (strcmp(tree->value.opaque, "chain") != 0)
		goto err;

	name = nft_mxml_str_parse(tree, "name", MXML_DESCEND_FIRST);
	if (name == NULL)
		goto err;

	strncpy(c->name, name, NFT_CHAIN_MAXNAMELEN);
	c->flags |= (1 << NFT_CHAIN_ATTR_NAME);

	if (nft_mxml_num_parse(tree, "handle", MXML_DESCEND_FIRST, BASE_DEC,
			       &c->handle, NFT_TYPE_U64) != 0)
		goto err;

	c->flags |= (1 << NFT_CHAIN_ATTR_HANDLE);

	if (nft_mxml_num_parse(tree, "bytes", MXML_DESCEND_FIRST, BASE_DEC,
			       &c->bytes, NFT_TYPE_U64) != 0)
		goto err;

	c->flags |= (1 << NFT_CHAIN_ATTR_BYTES);

	if (nft_mxml_num_parse(tree, "packets", MXML_DESCEND_FIRST, BASE_DEC,
			       &c->packets, NFT_TYPE_U64) != 0)
		goto err;

	c->flags |= (1 << NFT_CHAIN_ATTR_PACKETS);

	type = nft_mxml_str_parse(tree, "type", MXML_DESCEND_FIRST);
	if (type == NULL)
		goto err;

	if (c->type)
		xfree(c->type);

	c->type = strdup(type);
	c->flags |= (1 << NFT_CHAIN_ATTR_TYPE);

	table = nft_mxml_str_parse(tree, "table", MXML_DESCEND_FIRST);
	if (table == NULL)
		goto err;

	if (c->table)
		xfree(c->table);

	c->table = strdup(table);
	c->flags |= (1 << NFT_CHAIN_ATTR_TABLE);

	if (nft_mxml_num_parse(tree, "prio", MXML_DESCEND, BASE_DEC, &c->prio,
			       NFT_TYPE_S32) != 0)
		goto err;

	c->flags |= (1 << NFT_CHAIN_ATTR_PRIO);

	hooknum_str = nft_mxml_str_parse(tree, "hooknum", MXML_DESCEND_FIRST);
	if (hooknum_str == NULL)
		goto err;

	hooknum = nft_str2hooknum(hooknum_str);
	if (hooknum < 0)
		goto err;

	c->hooknum = hooknum;
	c->flags |= (1 << NFT_CHAIN_ATTR_HOOKNUM);

	policy_str = nft_mxml_str_parse(tree, "policy", MXML_DESCEND);
	if (policy_str == NULL)
		goto err;

	policy = nft_str2verdict(policy_str);
	if (policy == -1)
		goto err;

	c->policy = policy;
	c->flags |= (1 << NFT_CHAIN_ATTR_POLICY);

	family = nft_mxml_family_parse(tree, "family", MXML_DESCEND_FIRST);
	if (family < 0)
		goto err;

	c->family = family;
	c->flags |= (1 << NFT_CHAIN_ATTR_FAMILY);

	mxmlDelete(tree);
	return 0;
err:
	mxmlDelete(tree);
	return -1;
#else
	errno = EOPNOTSUPP;
	return -1;
#endif
}

int nft_chain_parse(struct nft_chain *c, enum nft_chain_parse_type type,
		    const char *data)
{
	int ret;

	switch (type) {
	case NFT_CHAIN_PARSE_XML:
		ret = nft_chain_xml_parse(c, data);
		break;
	case NFT_CHAIN_PARSE_JSON:
		ret = nft_chain_json_parse(c, data);
		break;
	default:
		ret = -1;
		errno = EOPNOTSUPP;
		break;
	}

	return ret;
}
EXPORT_SYMBOL(nft_chain_parse);

static int nft_chain_snprintf_json(char *buf, size_t size, struct nft_chain *c)
{
	int ret, len = size, offset = 0;

	ret = snprintf(buf, size,
		"{ \"chain\": {"
			"\"name\": \"%s\","
			"\"handle\": %"PRIu64","
			"\"bytes\": %"PRIu64","
			"\"packets\": %"PRIu64","
			"\"family\": \"%s\","
			"\"table\": \"%s\","
			"\"use\": %d",
			c->name, c->handle, c->bytes, c->packets,
			nft_family2str(c->family),
			c->table, c->use);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	if (c->flags & (1 << NFT_CHAIN_ATTR_HOOKNUM)) {
		ret =  snprintf(buf+offset, size,
				",\"type\": \"%s\","
				"\"hooknum\": \"%s\","
				"\"prio\": %d,"
				"\"policy\": \"%s\"",
			c->type, hooknum2str_array[c->hooknum], c->prio,
			nft_verdict2str(c->policy));
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	ret = snprintf(buf+offset, size,
		"}"
		"}");
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	return offset;
}

static int nft_chain_snprintf_xml(char *buf, size_t size, struct nft_chain *c)
{
	int ret, len = size, offset = 0;

	ret = snprintf(buf, size, "<chain><name>%s</name>"
		       "<handle>%"PRIu64"</handle><bytes>%"PRIu64"</bytes>"
		       "<packets>%"PRIu64"</packets><type>%s</type>"
		       "<table>%s</table><prio>%d</prio>"
		       "<hooknum>%s</hooknum>",
		       c->name, c->handle, c->bytes, c->packets,
		       c->type, c->table,
		       c->prio, hooknum2str_array[c->hooknum]);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	/* The parsing will fail both if there are something different
	 * than {accept|drop} or if the <policy> node is missing.
	 */
	if (c->policy == NF_ACCEPT) {
		ret = snprintf(buf+offset, size, "<policy>accept</policy>");
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	} else if (c->policy == NF_DROP) {
		ret = snprintf(buf+offset, size, "<policy>drop</policy>");
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

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

	return offset;
}

static int nft_chain_snprintf_default(char *buf, size_t size,
				      struct nft_chain *c)
{
	int ret, len = size, offset = 0;

	ret = snprintf(buf, size, "%s %s %s",
			nft_family2str(c->family), c->table, c->name);
	SNPRINTF_BUFFER_SIZE(ret, size, len, offset);

	if (c->flags & (1 << NFT_CHAIN_ATTR_HOOKNUM)) {
		ret = snprintf(buf+offset, size,
			       " type %s hook %s prio %d policy %s use %d "
			       "packets %"PRIu64" bytes %"PRIu64"",
			       c->type, hooknum2str_array[c->hooknum], c->prio,
			       nft_verdict2str(c->policy), c->use,
			       c->packets, c->bytes);
		SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
	}

	return offset;
}

int nft_chain_snprintf(char *buf, size_t size, struct nft_chain *c,
		       uint32_t type, uint32_t flags)
{
	switch(type) {
	case NFT_CHAIN_O_DEFAULT:
		return nft_chain_snprintf_default(buf, size, c);
	case NFT_CHAIN_O_XML:
		return nft_chain_snprintf_xml(buf, size, c);
	case NFT_CHAIN_O_JSON:
		return nft_chain_snprintf_json(buf, size, c);
	default:
		break;
	}
	return -1;
}
EXPORT_SYMBOL(nft_chain_snprintf);

struct nft_chain_list {
	struct list_head list;
};

struct nft_chain_list *nft_chain_list_alloc(void)
{
	struct nft_chain_list *list;

	list = calloc(1, sizeof(struct nft_chain_list));
	if (list == NULL)
		return NULL;

	INIT_LIST_HEAD(&list->list);

	return list;
}
EXPORT_SYMBOL(nft_chain_list_alloc);

void nft_chain_list_free(struct nft_chain_list *list)
{
	struct nft_chain *r, *tmp;

	list_for_each_entry_safe(r, tmp, &list->list, head) {
		list_del(&r->head);
		nft_chain_free(r);
	}
	xfree(list);
}
EXPORT_SYMBOL(nft_chain_list_free);

int nft_chain_list_is_empty(struct nft_chain_list *list)
{
	return list_empty(&list->list);
}
EXPORT_SYMBOL(nft_chain_list_is_empty);

void nft_chain_list_add(struct nft_chain *r, struct nft_chain_list *list)
{
	list_add(&r->head, &list->list);
}
EXPORT_SYMBOL(nft_chain_list_add);

void nft_chain_list_add_tail(struct nft_chain *r, struct nft_chain_list *list)
{
	list_add_tail(&r->head, &list->list);
}
EXPORT_SYMBOL(nft_chain_list_add_tail);

void nft_chain_list_del(struct nft_chain *r)
{
	list_del(&r->head);
}
EXPORT_SYMBOL(nft_chain_list_del);

int nft_chain_list_foreach(struct nft_chain_list *chain_list,
			   int (*cb)(struct nft_chain *r, void *data),
			   void *data)
{
	struct nft_chain *cur, *tmp;
	int ret;

	list_for_each_entry_safe(cur, tmp, &chain_list->list, head) {
		ret = cb(cur, data);
		if (ret < 0)
			return ret;
	}
	return 0;
}
EXPORT_SYMBOL(nft_chain_list_foreach);

struct nft_chain_list_iter {
	struct nft_chain_list	*list;
	struct nft_chain	*cur;
};

struct nft_chain_list_iter *nft_chain_list_iter_create(struct nft_chain_list *l)
{
	struct nft_chain_list_iter *iter;

	iter = calloc(1, sizeof(struct nft_chain_list_iter));
	if (iter == NULL)
		return NULL;

	iter->list = l;
	iter->cur = list_entry(l->list.next, struct nft_chain, head);

	return iter;
}
EXPORT_SYMBOL(nft_chain_list_iter_create);

struct nft_chain *nft_chain_list_iter_next(struct nft_chain_list_iter *iter)
{
	struct nft_chain *r = iter->cur;

	/* get next chain, if any */
	iter->cur = list_entry(iter->cur->head.next, struct nft_chain, head);
	if (&iter->cur->head == iter->list->list.next)
		return NULL;

	return r;
}
EXPORT_SYMBOL(nft_chain_list_iter_next);

void nft_chain_list_iter_destroy(struct nft_chain_list_iter *iter)
{
	xfree(iter);
}
EXPORT_SYMBOL(nft_chain_list_iter_destroy);