/src/suricata7/src/util-bpf.c
Line | Count | Source |
1 | | /* Copyright (C) 2018 Open Information Security Foundation |
2 | | * |
3 | | * You can copy, redistribute or modify this Program under the terms of |
4 | | * the GNU General Public License version 2 as published by the Free |
5 | | * Software Foundation. |
6 | | * |
7 | | * This program is distributed in the hope that it will be useful, |
8 | | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
9 | | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
10 | | * GNU General Public License for more details. |
11 | | * |
12 | | * You should have received a copy of the GNU General Public License |
13 | | * version 2 along with this program; if not, write to the Free Software |
14 | | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
15 | | * 02110-1301, USA. |
16 | | */ |
17 | | |
18 | | /** |
19 | | * \file |
20 | | * |
21 | | * \author Eric Leblond <eric@regit.org> |
22 | | */ |
23 | | |
24 | | #include "suricata-common.h" |
25 | | #include "util-bpf.h" |
26 | | #include "threads.h" |
27 | | #include "conf.h" |
28 | | #include "util-debug.h" |
29 | | |
30 | | void ConfSetBPFFilter( |
31 | | ConfNode *if_root, ConfNode *if_default, const char *iface, const char **bpf_filter) |
32 | 0 | { |
33 | 0 | if (*bpf_filter != NULL) { |
34 | 0 | SCLogInfo("BPF filter already configured"); |
35 | 0 | return; |
36 | 0 | } |
37 | | |
38 | | /* command line value has precedence */ |
39 | 0 | if (ConfGet("bpf-filter", bpf_filter) == 1) { |
40 | 0 | if (strlen(*bpf_filter) > 0) { |
41 | 0 | SCLogConfig("%s: using command-line provided bpf filter '%s'", iface, *bpf_filter); |
42 | 0 | } |
43 | 0 | } else if (ConfGetChildValueWithDefault(if_root, if_default, "bpf-filter", bpf_filter) == |
44 | 0 | 1) { // reading from a file |
45 | 0 | if (strlen(*bpf_filter) > 0) { |
46 | 0 | SCLogConfig("%s: using file provided bpf filter %s", iface, *bpf_filter); |
47 | 0 | } |
48 | 0 | } else { |
49 | 0 | SCLogDebug("No BPF filter found, skipping"); |
50 | 0 | } |
51 | 0 | } |
52 | | |
53 | | /** protect bpf filter build, as it is not thread safe */ |
54 | | static SCMutex bpf_set_filter_lock = SCMUTEX_INITIALIZER; |
55 | | |
56 | | void SCBPFFree(struct bpf_program *program) |
57 | 0 | { |
58 | 0 | if (program) |
59 | 0 | pcap_freecode(program); |
60 | 0 | } |
61 | | |
62 | | int SCBPFCompile(int snaplen_arg, int linktype_arg, struct bpf_program *program, |
63 | | const char *buf, |
64 | | int optimize, uint32_t mask, |
65 | | char *errbuf, size_t errbuf_len) |
66 | 0 | { |
67 | 0 | pcap_t *p; |
68 | 0 | int ret; |
69 | |
|
70 | 0 | p = pcap_open_dead(linktype_arg, snaplen_arg); |
71 | 0 | if (p == NULL) |
72 | 0 | return (-1); |
73 | | |
74 | 0 | SCMutexLock(&bpf_set_filter_lock); |
75 | 0 | ret = pcap_compile(p, program, buf, optimize, mask); |
76 | 0 | if (ret == -1) { |
77 | 0 | if (errbuf) { |
78 | 0 | snprintf(errbuf, errbuf_len, "%s", pcap_geterr(p)); |
79 | 0 | } |
80 | 0 | pcap_close(p); |
81 | 0 | SCMutexUnlock(&bpf_set_filter_lock); |
82 | 0 | return (-1); |
83 | 0 | } |
84 | 0 | pcap_close(p); |
85 | 0 | SCMutexUnlock(&bpf_set_filter_lock); |
86 | |
|
87 | 0 | if (program->bf_insns == NULL) { |
88 | 0 | if (errbuf) { |
89 | 0 | snprintf(errbuf, errbuf_len, "Filter badly setup"); |
90 | 0 | } |
91 | 0 | SCBPFFree(program); |
92 | 0 | return (-1); |
93 | 0 | } |
94 | | |
95 | 0 | return (ret); |
96 | 0 | } |