libnetfilter_conntrack  1.0.6
nfct-mnl-set-label.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <time.h>
5 
6 #include <libmnl/libmnl.h>
7 #include <libnetfilter_conntrack/libnetfilter_conntrack.h>
8 
9 struct callback_args {
10  struct mnl_socket *nl;
11  unsigned int seq;
12  int bit;
13 };
14 
15 static void set_label(struct nf_conntrack *ct, struct callback_args *cbargs)
16 {
17  struct nfct_bitmask *b = (void *) nfct_get_attr(ct, ATTR_CONNLABELS);
18  int bit = cbargs->bit;
19  char buf[MNL_SOCKET_BUFFER_SIZE];
20  struct nlmsghdr *nlh;
21  struct nfgenmsg *nfh;
22 
23  if (b) {
24  if (bit < 0)
25  b = nfct_bitmask_new(0);
26  else if (nfct_bitmask_test_bit(b, bit))
27  return;
28  } else {
29  b = nfct_bitmask_new(0);
30  }
31 
32  if (!b)
33  return;
34  if (bit >= 0)
35  nfct_bitmask_set_bit(b, bit);
36  nfct_set_attr(ct, ATTR_CONNLABELS, b);
37 
38  if (bit >= 0) {
39  b = nfct_bitmask_new(bit);
40  if (b) {
41  nfct_bitmask_set_bit(b, bit);
42  nfct_set_attr(ct, ATTR_CONNLABELS_MASK, b);
43  }
44  }
45 
46  cbargs->seq++;
47 
48  nlh = mnl_nlmsg_put_header(buf);
49  nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW;
50  nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE;
51  nlh->nlmsg_seq = cbargs->seq;
52 
53  nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
54  nfh->nfgen_family = nfct_get_attr_u8(ct, ATTR_L3PROTO);
55  nfh->version = NFNETLINK_V0;
56  nfh->res_id = 0;
57 
58  nfct_nlmsg_build(nlh, ct);
59 
60  if (mnl_socket_sendto(cbargs->nl, nlh, nlh->nlmsg_len) < 0)
61  perror("mnl_socket_sendto");
62 }
63 
64 static int data_cb(const struct nlmsghdr *nlh, void *data)
65 {
66  struct nf_conntrack *ct;
67  char buf[4096];
68 
69  ct = nfct_new();
70  if (ct == NULL)
71  return MNL_CB_OK;
72 
73  nfct_nlmsg_parse(nlh, ct);
74 
75  nfct_snprintf(buf, sizeof(buf), ct, NFCT_T_UNKNOWN, NFCT_O_DEFAULT, 0);
76  printf("%s\n", buf);
77 
78  set_label(ct, data);
79 
80  nfct_destroy(ct);
81 
82  return MNL_CB_OK;
83 }
84 
85 static void show_labels(struct nfct_labelmap *l)
86 {
87  unsigned int i = 0;
88  const char *name;
89 
90  if (l) {
91  fputs("usage: program label, configured labels are:\n", stderr);
92  while ((name = nfct_labelmap_get_name(l, i))) {
93  if (*name)
94  fprintf(stderr, "%s -> bit %d\n", name, i);
95  i++;
96  }
97  } else {
98  fputs("no labels configured, usage: program bit\n", stderr);
99  }
100  exit(1);
101 }
102 
103 static struct mnl_socket *sock_nl_create(void)
104 {
105  struct mnl_socket *nl;
106 
107  nl = mnl_socket_open(NETLINK_NETFILTER);
108  if (nl == NULL) {
109  perror("mnl_socket_open");
110  exit(EXIT_FAILURE);
111  }
112 
113  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
114  perror("mnl_socket_bind");
115  exit(EXIT_FAILURE);
116  }
117 
118  return nl;
119 }
120 
121 int main(int argc, char *argv[])
122 {
123  struct mnl_socket *nl;
124  struct nlmsghdr *nlh;
125  struct nfgenmsg *nfh;
126  char buf[MNL_SOCKET_BUFFER_SIZE];
127  unsigned int seq, portid;
128  struct callback_args cbargs;
129  int ret;
130  struct nfct_labelmap *l = nfct_labelmap_new(NULL);
131 
132  if (argc < 2)
133  show_labels(l);
134 
135  cbargs.bit = l ? nfct_labelmap_get_bit(l, argv[1]) : -1;
136 
137  if (cbargs.bit < 0) {
138  cbargs.bit = atoi(argv[1]);
139  if (cbargs.bit == 0 && argv[1][0] != '0')
140  show_labels(l);
141  }
142 
143  if (cbargs.bit < 0)
144  puts("will clear all labels");
145  else
146  printf("will set label bit %d\n", cbargs.bit);
147 
148  nl = sock_nl_create();
149  portid = mnl_socket_get_portid(nl);
150 
151  nlh = mnl_nlmsg_put_header(buf);
152  nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_GET;
153  nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP;
154  nlh->nlmsg_seq = seq = time(NULL);
155 
156  nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
157  nfh->nfgen_family = AF_UNSPEC;
158  nfh->version = NFNETLINK_V0;
159  nfh->res_id = 0;
160 
161 
162  ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
163  if (ret == -1) {
164  perror("mnl_socket_sendto");
165  exit(EXIT_FAILURE);
166  }
167 
168  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
169 
170 
171  cbargs.nl = sock_nl_create();
172  cbargs.seq = seq;
173 
174  while (ret > 0) {
175  ret = mnl_cb_run(buf, ret, seq, portid, data_cb, &cbargs);
176  if (ret <= MNL_CB_STOP)
177  break;
178  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
179  }
180  if (ret == -1) {
181  perror("mnl_socket_recvfrom");
182  exit(EXIT_FAILURE);
183  }
184 
185  if (l)
187  mnl_socket_close(nl);
188 
189  return 0;
190 }
uint8_t nfct_get_attr_u8(const struct nf_conntrack *ct, const enum nf_conntrack_attr type)
const char * nfct_labelmap_get_name(struct nfct_labelmap *m, unsigned int bit)
void nfct_set_attr(struct nf_conntrack *ct, const enum nf_conntrack_attr type, const void *value)
void nfct_destroy(struct nf_conntrack *ct)
Definition: conntrack/api.c:92
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)
struct nfct_labelmap * nfct_labelmap_new(const char *mapfile)
struct nf_conntrack * nfct_new(void)
Definition: conntrack/api.c:75
const void * nfct_get_attr(const struct nf_conntrack *ct, const enum nf_conntrack_attr type)
int nfct_labelmap_get_bit(struct nfct_labelmap *m, const char *name)
void nfct_labelmap_destroy(struct nfct_labelmap *map)