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/* Copyright (C) 2018 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Eric Leblond <eric@regit.org>
*/
#include "suricata-common.h"
#include "util-bpf.h"
#include "threads.h"
#include "conf.h"
#include "util-debug.h"
void ConfSetBPFFilter(
ConfNode *if_root, ConfNode *if_default, const char *iface, const char **bpf_filter)
{
if (*bpf_filter != NULL) {
SCLogInfo("BPF filter already configured");
return;
}
/* command line value has precedence */
if (ConfGet("bpf-filter", bpf_filter) == 1) {
if (strlen(*bpf_filter) > 0) {
SCLogConfig("%s: using command-line provided bpf filter '%s'", iface, *bpf_filter);
}
} else if (ConfGetChildValueWithDefault(if_root, if_default, "bpf-filter", bpf_filter) ==
1) { // reading from a file
if (strlen(*bpf_filter) > 0) {
SCLogConfig("%s: using file provided bpf filter %s", iface, *bpf_filter);
}
} else {
SCLogDebug("No BPF filter found, skipping");
}
}
/** protect bpf filter build, as it is not thread safe */
static SCMutex bpf_set_filter_lock = SCMUTEX_INITIALIZER;
void SCBPFFree(struct bpf_program *program)
{
if (program)
pcap_freecode(program);
}
int SCBPFCompile(int snaplen_arg, int linktype_arg, struct bpf_program *program,
const char *buf,
int optimize, uint32_t mask,
char *errbuf, size_t errbuf_len)
{
pcap_t *p;
int ret;
p = pcap_open_dead(linktype_arg, snaplen_arg);
if (p == NULL)
return (-1);
SCMutexLock(&bpf_set_filter_lock);
ret = pcap_compile(p, program, buf, optimize, mask);
if (ret == -1) {
if (errbuf) {
snprintf(errbuf, errbuf_len, "%s", pcap_geterr(p));
}
pcap_close(p);
SCMutexUnlock(&bpf_set_filter_lock);
return (-1);
}
pcap_close(p);
SCMutexUnlock(&bpf_set_filter_lock);
if (program->bf_insns == NULL) {
if (errbuf) {
snprintf(errbuf, errbuf_len, "Filter badly setup");
}
SCBPFFree(program);
return (-1);
}
return (ret);
}
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