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      1 /*
      2  * (C) 2005-2011 by Pablo Neira Ayuso <pablo (at) netfilter.org>
      3  *                  Harald Welte <laforge (at) netfilter.org>
      4  *
      5  * This program is free software; you can redistribute it and/or modify it
      6  * under the terms of the GNU General Public License as published by
      7  * the Free Software Foundation; either version 2 of the License, or
      8  * (at your option) any later version.
      9  */
     10 #include <libnfnetlink/libnfnetlink.h>
     11 #include <libnetfilter_conntrack/libnetfilter_conntrack.h>
     12 
     13 #include "internal/internal.h"
     14 
     15 struct nfct_handle *nfct_open_nfnl(struct nfnl_handle *nfnlh,
     16 				   uint8_t subsys_id,
     17 				   unsigned int subscriptions)
     18 {
     19 	struct nfct_handle *cth;
     20 
     21 	cth = malloc(sizeof(struct nfct_handle));
     22 	if (!cth)
     23 		return NULL;
     24 
     25 	memset(cth, 0, sizeof(*cth));
     26 	cth->nfnlh = nfnlh;
     27 
     28 	if (subsys_id == 0 || subsys_id == NFNL_SUBSYS_CTNETLINK) {
     29 		cth->nfnlssh_ct = nfnl_subsys_open(cth->nfnlh,
     30 						   NFNL_SUBSYS_CTNETLINK,
     31 						   IPCTNL_MSG_MAX,
     32 						   subscriptions);
     33 		if (!cth->nfnlssh_ct)
     34 			goto out_free;
     35 	}
     36 
     37 	if (subsys_id == 0 || subsys_id == NFNL_SUBSYS_CTNETLINK_EXP) {
     38 		cth->nfnlssh_exp = nfnl_subsys_open(cth->nfnlh,
     39 						    NFNL_SUBSYS_CTNETLINK_EXP,
     40 						    IPCTNL_MSG_EXP_MAX,
     41 						    subscriptions);
     42 		if (!cth->nfnlssh_exp)
     43 			goto out_free;
     44 	}
     45 
     46 	return cth;
     47 
     48 out_free:
     49 	if (cth->nfnlssh_exp) {
     50 		nfnl_subsys_close(cth->nfnlssh_exp);
     51 		cth->nfnlssh_exp = NULL;
     52 	}
     53 	if (cth->nfnlssh_ct) {
     54 		nfnl_subsys_close(cth->nfnlssh_ct);
     55 		cth->nfnlssh_ct = NULL;
     56 	}
     57 	free(cth);
     58 	return NULL;
     59 }
     60 
     61 /**
     62  * \defgroup LibrarySetup Library setup
     63  * @{
     64  */
     65 
     66 
     67 /**
     68  * nfct_open - open a ctnetlink handler
     69  * \param subsys_id can be NFNL_SUBSYS_CTNETLINK or NFNL_SUBSYS_CTNETLINK_EXP
     70  * \param subscriptions ctnetlink groups to subscribe to events
     71  *
     72  * This function returns a handler to send commands to and receive replies from
     73  * kernel-space. You can pass the following subsystem IDs:
     74  *
     75  * - NFNL_SUBSYS_CTNETLINK: if you are only interested in conntrack operations
     76  * (excluding expectations).
     77  * - NFNL_SUBSYS_CTNETLINK_EXP: if you are only interested in expectation
     78  * operations (exclude conntracks).
     79  * - NFNL_SUBSYS_NONE: if you are interested in both conntrack and expectation
     80  * operations.
     81  *
     82  * On error, NULL is returned and errno is explicitly set.
     83  */
     84 struct nfct_handle *nfct_open(uint8_t subsys_id, unsigned subscriptions)
     85 {
     86 	struct nfnl_handle *nfnlh = nfnl_open();
     87 	struct nfct_handle *nfcth;
     88 
     89 	if (!nfnlh)
     90 		return NULL;
     91 
     92 	nfcth = nfct_open_nfnl(nfnlh, subsys_id, subscriptions);
     93 	if (!nfcth)
     94 		nfnl_close(nfnlh);
     95 
     96 	return nfcth;
     97 }
     98 
     99 /**
    100  * nfct_close - close a ctnetlink handler
    101  * \param cth handler obtained via nfct_open()
    102  *
    103  * This function returns -1 on error and errno is explicitly set.
    104  */
    105 int nfct_close(struct nfct_handle *cth)
    106 {
    107 	int err;
    108 
    109 	if (cth->nfnlssh_exp) {
    110 		nfnl_subsys_close(cth->nfnlssh_exp);
    111 		cth->nfnlssh_exp = NULL;
    112 	}
    113 	if (cth->nfnlssh_ct) {
    114 		nfnl_subsys_close(cth->nfnlssh_ct);
    115 		cth->nfnlssh_ct = NULL;
    116 	}
    117 
    118 	/* required by the new API */
    119 	cth->cb = NULL;
    120 	cth->cb2 = NULL;
    121 	cth->expect_cb = NULL;
    122 	cth->expect_cb2 = NULL;
    123 	free(cth->nfnl_cb_ct.data);
    124 	free(cth->nfnl_cb_exp.data);
    125 
    126 	cth->nfnl_cb_ct.call = NULL;
    127 	cth->nfnl_cb_ct.data = NULL;
    128 	cth->nfnl_cb_ct.attr_count = 0;
    129 
    130 	cth->nfnl_cb_exp.call = NULL;
    131 	cth->nfnl_cb_exp.data = NULL;
    132 	cth->nfnl_cb_exp.attr_count = 0;
    133 
    134 	err = nfnl_close(cth->nfnlh);
    135 	free(cth);
    136 
    137 	return err;
    138 }
    139 
    140 /**
    141  * nfct_fd - get the Netlink file descriptor of one existing ctnetlink handler
    142  * \param cth handler obtained via nfct_open()
    143  */
    144 int nfct_fd(struct nfct_handle *cth)
    145 {
    146 	return nfnl_fd(cth->nfnlh);
    147 }
    148 
    149 const struct nfnl_handle *nfct_nfnlh(struct nfct_handle *cth)
    150 {
    151 	return cth->nfnlh;
    152 }
    153 
    154 /**
    155  * @}
    156  */
    157