1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
/*
* (C) 2010 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
static int parse_ip_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = (const struct nlattr **)data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTA_IP_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case CTA_IP_V4_SRC:
case CTA_IP_V4_DST:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void print_ip(const struct nlattr *nest)
{
struct nlattr *tb[CTA_IP_MAX+1] = {};
mnl_attr_parse_nested(nest, parse_ip_cb, tb);
if (tb[CTA_IP_V4_SRC]) {
struct in_addr *in = mnl_attr_get_payload(tb[CTA_IP_V4_SRC]);
printf("src=%s ", inet_ntoa(*in));
}
if (tb[CTA_IP_V4_DST]) {
struct in_addr *in = mnl_attr_get_payload(tb[CTA_IP_V4_DST]);
printf("dst=%s ", inet_ntoa(*in));
}
}
static int parse_proto_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = (const struct nlattr **)data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTA_PROTO_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case CTA_PROTO_NUM:
case CTA_PROTO_ICMP_TYPE:
case CTA_PROTO_ICMP_CODE:
if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
case CTA_PROTO_SRC_PORT:
case CTA_PROTO_DST_PORT:
case CTA_PROTO_ICMP_ID:
if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void print_proto(const struct nlattr *nest)
{
struct nlattr *tb[CTA_PROTO_MAX+1] = {};
mnl_attr_parse_nested(nest, parse_proto_cb, tb);
if (tb[CTA_PROTO_NUM]) {
printf("proto=%u ", mnl_attr_get_u16(tb[CTA_PROTO_NUM]));
}
if (tb[CTA_PROTO_SRC_PORT]) {
printf("sport=%u ", mnl_attr_get_u16(tb[CTA_PROTO_SRC_PORT]));
}
if (tb[CTA_PROTO_DST_PORT]) {
printf("dport=%u ", mnl_attr_get_u16(tb[CTA_PROTO_DST_PORT]));
}
if (tb[CTA_PROTO_ICMP_ID]) {
printf("id=%u ", mnl_attr_get_u16(tb[CTA_PROTO_ICMP_ID]));
}
if (tb[CTA_PROTO_ICMP_TYPE]) {
printf("type=%u ", mnl_attr_get_u16(tb[CTA_PROTO_ICMP_TYPE]));
}
if (tb[CTA_PROTO_ICMP_CODE]) {
printf("code=%u ", mnl_attr_get_u16(tb[CTA_PROTO_ICMP_CODE]));
}
}
static int parse_tuple_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = (const struct nlattr **)data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTA_TUPLE_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case CTA_TUPLE_IP:
if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
case CTA_TUPLE_PROTO:
if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static void print_tuple(const struct nlattr *nest)
{
struct nlattr *tb[CTA_TUPLE_MAX+1] = {};
mnl_attr_parse_nested(nest, parse_tuple_cb, tb);
if (tb[CTA_TUPLE_IP]) {
print_ip(tb[CTA_TUPLE_IP]);
}
if (tb[CTA_TUPLE_PROTO]) {
print_proto(tb[CTA_TUPLE_PROTO]);
}
}
static int data_attr_cb(const struct nlattr *attr, void *data)
{
const struct nlattr **tb = (const struct nlattr **)data;
int type = mnl_attr_get_type(attr);
if (mnl_attr_type_valid(attr, CTA_MAX) < 0)
return MNL_CB_OK;
switch(type) {
case CTA_TUPLE_ORIG:
if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
case CTA_TIMEOUT:
case CTA_MARK:
case CTA_SECMARK:
if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
perror("mnl_attr_validate");
return MNL_CB_ERROR;
}
break;
}
tb[type] = attr;
return MNL_CB_OK;
}
static int data_cb(const struct nlmsghdr *nlh, void *data)
{
struct nlattr *tb[CTA_MAX+1] = {};
struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
switch(nlh->nlmsg_type & 0xFF) {
case IPCTNL_MSG_CT_NEW:
if (nlh->nlmsg_flags & (NLM_F_CREATE|NLM_F_EXCL))
printf("%9s ", "[NEW] ");
else
printf("%9s ", "[UPDATE] ");
break;
case IPCTNL_MSG_CT_DELETE:
printf("%9s ", "[DESTROY] ");
break;
}
mnl_attr_parse(nlh, sizeof(*nfg), data_attr_cb, tb);
if (tb[CTA_TUPLE_ORIG]) {
print_tuple(tb[CTA_TUPLE_ORIG]);
}
if (tb[CTA_MARK]) {
printf("mark=%u ", mnl_attr_get_u32(tb[CTA_MARK]));
}
if (tb[CTA_SECMARK]) {
printf("secmark=%u ", mnl_attr_get_u32(tb[CTA_SECMARK]));
}
printf("\n");
return MNL_CB_OK;
}
int main()
{
struct mnl_socket *nl;
char buf[getpagesize()];
int ret;
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL) {
perror("mnl_socket_open");
exit(EXIT_FAILURE);
}
if (mnl_socket_bind(nl, NFNLGRP_CONNTRACK_NEW |
NFNLGRP_CONNTRACK_UPDATE |
NFNLGRP_CONNTRACK_DESTROY,
MNL_SOCKET_AUTOPID) < 0) {
perror("mnl_socket_bind");
exit(EXIT_FAILURE);
}
while (1) {
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
if (ret == -1) {
perror("mnl_socket_recvfrom");
exit(EXIT_FAILURE);
}
ret = mnl_cb_run(buf, ret, 0, 0, data_cb, NULL);
if (ret == -1) {
perror("mnl_cb_run");
exit(EXIT_FAILURE);
}
}
mnl_socket_close(nl);
return 0;
}
|
