libnetfilter_conntrack 1.0.9
conntrack_filter.c
1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <errno.h>
5#include <arpa/inet.h>
6
7#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
8#include <libnetfilter_conntrack/libnetfilter_conntrack_tcp.h>
9
10static int event_cb(enum nf_conntrack_msg_type type,
11 struct nf_conntrack *ct,
12 void *data)
13{
14 static int n = 0;
15 char buf[1024];
16
17 nfct_snprintf(buf, sizeof(buf), ct, type, NFCT_O_PLAIN, NFCT_OF_TIME);
18 printf("%s\n", buf);
19
20 if (++n == 10)
21 return NFCT_CB_STOP;
22
23 return NFCT_CB_CONTINUE;
24}
25
26int main(void)
27{
28 int ret;
29 struct nfct_handle *h;
30 struct nfct_filter *filter;
31
32 h = nfct_open(CONNTRACK, NF_NETLINK_CONNTRACK_NEW |
33 NF_NETLINK_CONNTRACK_UPDATE);
34 if (!h) {
35 perror("nfct_open");
36 return 0;
37 }
38
39 filter = nfct_filter_create();
40 if (!filter) {
41 perror("nfct_create_filter");
42 return 0;
43 }
44
45 nfct_filter_add_attr_u32(filter, NFCT_FILTER_L4PROTO, IPPROTO_UDP);
46 nfct_filter_add_attr_u32(filter, NFCT_FILTER_L4PROTO, IPPROTO_TCP);
47
48 struct nfct_filter_proto filter_proto = {
49 .proto = IPPROTO_TCP,
50 .state = TCP_CONNTRACK_ESTABLISHED
51 };
52
53 nfct_filter_add_attr(filter, NFCT_FILTER_L4PROTO_STATE, &filter_proto);
54
55 /* BSF always wants data in host-byte order */
56 struct nfct_filter_ipv4 filter_ipv4 = {
57 .addr = ntohl(inet_addr("127.0.0.1")),
58 .mask = 0xffffffff,
59 };
60
61 /* ignore whatever that comes from 127.0.0.1 */
63 NFCT_FILTER_SRC_IPV4,
64 NFCT_FILTER_LOGIC_NEGATIVE);
65
66 nfct_filter_add_attr(filter, NFCT_FILTER_SRC_IPV4, &filter_ipv4);
67
68 /* BSF always wants data in host-byte order */
69 struct nfct_filter_ipv6 filter_ipv6 = {
70 .addr = { 0x0, 0x0, 0x0, 0x1 },
71 .mask = { 0xffffffff, 0xffffffff, 0xffffffff, 0xffffffff },
72 };
73
74 /* ignore whatever that comes from ::1 (loopback) */
76 NFCT_FILTER_SRC_IPV6,
77 NFCT_FILTER_LOGIC_NEGATIVE);
78
79 nfct_filter_add_attr(filter, NFCT_FILTER_SRC_IPV6, &filter_ipv6);
80
81 if (nfct_filter_attach(nfct_fd(h), filter) == -1) {
82 perror("nfct_filter_attach");
83 return 0;
84 }
85
86 /* release the filter object, this does not detach the filter */
87 nfct_filter_destroy(filter);
88
89 nfct_callback_register(h, NFCT_T_ALL, event_cb, NULL);
90
91 printf("TEST: waiting for 10 events...\n");
92
93 ret = nfct_catch(h);
94
95 printf("TEST: conntrack events ");
96 if (ret == -1)
97 printf("(%d)(%s)\n", ret, strerror(errno));
98 else
99 printf("(OK)\n");
100
101 nfct_close(h);
102
103 ret == -1 ? exit(EXIT_FAILURE) : exit(EXIT_SUCCESS);
104}
int nfct_callback_register(struct nfct_handle *h, enum nf_conntrack_msg_type type, int(*cb)(enum nf_conntrack_msg_type type, struct nf_conntrack *ct, void *data), void *data)
struct nfct_handle * nfct_open(uint8_t, unsigned)
Definition: main.c:84
int nfct_close(struct nfct_handle *cth)
Definition: main.c:105
int nfct_fd(struct nfct_handle *cth)
Definition: main.c:144
void nfct_filter_destroy(struct nfct_filter *filter)
int nfct_filter_set_logic(struct nfct_filter *filter, const enum nfct_filter_attr attr, const enum nfct_filter_logic logic)
int nfct_filter_attach(int fd, struct nfct_filter *filter)
void nfct_filter_add_attr_u32(struct nfct_filter *filter, const enum nfct_filter_attr attr, const uint32_t value)
void nfct_filter_add_attr(struct nfct_filter *filter, const enum nfct_filter_attr attr, const void *value)
struct nfct_filter * nfct_filter_create(void)
int nfct_catch(struct nfct_handle *h)
int nfct_snprintf(char *buf, unsigned int size, const struct nf_conntrack *ct, const unsigned int msg_type, const unsigned int out_type, const unsigned int out_flags)