src/main.c

/*
 * (C) 2005-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
 *                  Harald Welte <laforge@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.
 */
#include <libnfnetlink/libnfnetlink.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>

#include "internal/internal.h"

struct nfct_handle *nfct_open_nfnl(struct nfnl_handle *nfnlh,
				   uint8_t subsys_id,
				   unsigned int subscriptions)
{

	return nfct_open_nfnl2(nfnlh, subsys_id, subscriptions, true);
}

struct nfct_handle *nfct_open_nfnl2(struct nfnl_handle *nfnlh,
				   uint8_t subsys_id,
				   unsigned int subscriptions, bool bind)
{
	struct nfct_handle *cth;

	cth = malloc(sizeof(struct nfct_handle));
	if (!cth)
		return NULL;
	memset(cth, 0, sizeof(*cth));
	cth->nfnlh = nfnlh;

	if (subsys_id == 0 || subsys_id == NFNL_SUBSYS_CTNETLINK) {
		cth->nfnlssh_ct = nfnl_subsys_open2(cth->nfnlh,
						   NFNL_SUBSYS_CTNETLINK,
						   IPCTNL_MSG_MAX,
						   subscriptions,
						   bind);
		if (!cth->nfnlssh_ct)
			goto out_free;
	}

	if (subsys_id == 0 || subsys_id == NFNL_SUBSYS_CTNETLINK_EXP) {
		cth->nfnlssh_exp = nfnl_subsys_open2(cth->nfnlh,
						    NFNL_SUBSYS_CTNETLINK_EXP,
						    IPCTNL_MSG_EXP_MAX,
						    subscriptions,
						    bind);
		if (!cth->nfnlssh_exp)
			goto out_free;
	}

	return cth;

out_free:
	if (cth->nfnlssh_exp) {
		nfnl_subsys_close(cth->nfnlssh_exp);
		cth->nfnlssh_exp = NULL;
	}
	if (cth->nfnlssh_ct) {
		nfnl_subsys_close(cth->nfnlssh_ct);
		cth->nfnlssh_ct = NULL;
	}
	free(cth);
	return NULL;
}
/**
 * \defgroup LibrarySetup Library setup
 * @{
 */


/**
 * nfct_open - open a ctnetlink handler
 * \param subsys_id can be NFNL_SUBSYS_CTNETLINK or NFNL_SUBSYS_CTNETLINK_EXP
 * \param subscriptions ctnetlink groups to subscribe to events
 *
 * This function returns a handler to send commands to and receive replies from
 * kernel-space. You can pass the following subsystem IDs:
 *
 * - NFNL_SUBSYS_CTNETLINK: if you are only interested in conntrack operations
 * (excluding expectations).
 * - NFNL_SUBSYS_CTNETLINK_EXP: if you are only interested in expectation
 * operations (exclude conntracks).
 * - NFNL_SUBSYS_NONE: if you are interested in both conntrack and expectation
 * operations.
 *
 * On error, NULL is returned and errno is explicitly set.
 */
struct nfct_handle *nfct_open(uint8_t subsys_id, unsigned subscriptions)
{
	struct nfnl_handle *nfnlh = nfnl_open();
	struct nfct_handle *nfcth;

	if (!nfnlh)
		return NULL;

	nfcth = nfct_open_nfnl(nfnlh, subsys_id, subscriptions);
	if (!nfcth)
		nfnl_close(nfnlh);
	return nfcth;
}

/**
 * nfct_open2 - open a ctnetlink handler by given fd
 * \param subsys_id can be NFNL_SUBSYS_CTNETLINK or NFNL_SUBSYS_CTNETLINK_EXP
 * \param subscriptions ctnetlink groups to subscribe to events
 * \param fd use bound file descriptor to get nfnl_handle
 *
 * This function returns a handler to send commands to and receive replies from
 * kernel-space. You can pass the following subsystem IDs:
 *
 * - NFNL_SUBSYS_CTNETLINK: if you are only interested in conntrack operations
 * (excluding expectations).
 * - NFNL_SUBSYS_CTNETLINK_EXP: if you are only interested in expectation
 * operations (exclude conntracks).
 * - NFNL_SUBSYS_NONE: if you are interested in both conntrack and expectation
 * operations.
 *
 * On error, NULL is returned and errno is explicitly set.
 */
struct nfct_handle *nfct_open2(uint8_t subsys_id, unsigned subscriptions, int fd)
{
	struct nfnl_handle *nfnlh = nfnl_open2(fd, false);
	struct nfct_handle *nfcth;

	if (!nfnlh)
		return NULL;

	nfcth = nfct_open_nfnl2(nfnlh, subsys_id, subscriptions, false);
	if (!nfcth) {
		nfnl_close2(nfnlh);
	}
	return nfcth;
}

/**
 * nfct_close - close a ctnetlink handler
 * \param cth handler obtained via nfct_open()
 *
 * This function returns -1 on error and errno is explicitly set.
 */
int nfct_close(struct nfct_handle *cth)
{
	return nfct_close2(cth, false);
}

/**
 * nfct_close2 - close a ctnetlink handler
 * \param cth handler obtained via nfct_open()
 * \param keep_fd to indicate not close the file descriptor
 *
 * This function returns -1 on error and errno is explicitly set.
 */
int nfct_close2(struct nfct_handle *cth, bool keep_fd)
{
	int err;

	if (cth->nfnlssh_exp) {
		nfnl_subsys_close(cth->nfnlssh_exp);
		cth->nfnlssh_exp = NULL;
	}
	if (cth->nfnlssh_ct) {
		nfnl_subsys_close(cth->nfnlssh_ct);
		cth->nfnlssh_ct = NULL;
	}

	/* required by the new API */
	cth->cb = NULL;
	cth->cb2 = NULL;
	cth->expect_cb = NULL;
	cth->expect_cb2 = NULL;
	free(cth->nfnl_cb_ct.data);
	free(cth->nfnl_cb_exp.data);

	cth->nfnl_cb_ct.call = NULL;
	cth->nfnl_cb_ct.data = NULL;
	cth->nfnl_cb_ct.attr_count = 0;

	cth->nfnl_cb_exp.call = NULL;
	cth->nfnl_cb_exp.data = NULL;
	cth->nfnl_cb_exp.attr_count = 0;

	if (keep_fd)
		err = nfnl_close2(cth->nfnlh);
	else
	err = nfnl_close(cth->nfnlh);
	free(cth);

	return err;
}

/**
 * nfct_fd - get the Netlink file descriptor of one existing ctnetlink handler
 * \param cth handler obtained via nfct_open()
 */
int nfct_fd(struct nfct_handle *cth)
{
	return nfnl_fd(cth->nfnlh);
}

const struct nfnl_handle *nfct_nfnlh(struct nfct_handle *cth)
{
	return cth->nfnlh;
}

/**
 * @}
 */