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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <libmnl/libmnl.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
struct callback_args {
struct mnl_socket *nl;
unsigned int seq;
int bit;
};
static void set_label(struct nf_conntrack *ct, struct callback_args *cbargs)
{
struct nfct_bitmask *b = (void *) nfct_get_attr(ct, ATTR_CONNLABELS);
int bit = cbargs->bit;
char buf[MNL_SOCKET_BUFFER_SIZE];
struct nlmsghdr *nlh;
struct nfgenmsg *nfh;
if (b) {
if (bit < 0)
b = nfct_bitmask_new(0);
else if (nfct_bitmask_test_bit(b, bit))
return;
} else {
b = nfct_bitmask_new(0);
}
if (!b)
return;
if (bit >= 0)
nfct_bitmask_set_bit(b, bit);
nfct_set_attr(ct, ATTR_CONNLABELS, b);
if (bit >= 0) {
b = nfct_bitmask_new(bit);
if (b) {
nfct_bitmask_set_bit(b, bit);
nfct_set_attr(ct, ATTR_CONNLABELS_MASK, b);
}
}
cbargs->seq++;
nlh = mnl_nlmsg_put_header(buf);
nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_NEW;
nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE;
nlh->nlmsg_seq = cbargs->seq;
nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
nfh->nfgen_family = nfct_get_attr_u8(ct, ATTR_L3PROTO);
nfh->version = NFNETLINK_V0;
nfh->res_id = 0;
nfct_nlmsg_build(nlh, ct);
if (mnl_socket_sendto(cbargs->nl, nlh, nlh->nlmsg_len) < 0)
perror("mnl_socket_sendto");
}
static int data_cb(const struct nlmsghdr *nlh, void *data)
{
struct nf_conntrack *ct;
char buf[4096];
ct = nfct_new();
if (ct == NULL)
return MNL_CB_OK;
nfct_nlmsg_parse(nlh, ct);
nfct_snprintf(buf, sizeof(buf), ct, NFCT_T_UNKNOWN, NFCT_O_DEFAULT, 0);
printf("%s\n", buf);
set_label(ct, data);
nfct_destroy(ct);
return MNL_CB_OK;
}
static void show_labels(struct nfct_labelmap *l)
{
unsigned int i = 0;
const char *name;
if (l) {
fputs("usage: program label, configured labels are:\n", stderr);
while ((name = nfct_labelmap_get_name(l, i))) {
if (*name)
fprintf(stderr, "%s -> bit %d\n", name, i);
i++;
}
} else {
fputs("no labels configured, usage: program bit\n", stderr);
}
exit(1);
}
static struct mnl_socket *sock_nl_create(void)
{
struct mnl_socket *nl;
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL) {
perror("mnl_socket_open");
exit(EXIT_FAILURE);
}
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
perror("mnl_socket_bind");
exit(EXIT_FAILURE);
}
return nl;
}
int main(int argc, char *argv[])
{
struct mnl_socket *nl;
struct nlmsghdr *nlh;
struct nfgenmsg *nfh;
char buf[MNL_SOCKET_BUFFER_SIZE];
unsigned int seq, portid;
struct callback_args cbargs;
int ret;
struct nfct_labelmap *l = nfct_labelmap_new(NULL);
if (argc < 2)
show_labels(l);
cbargs.bit = l ? nfct_labelmap_get_bit(l, argv[1]) : -1;
if (cbargs.bit < 0) {
cbargs.bit = atoi(argv[1]);
if (cbargs.bit == 0 && argv[1][0] != '0')
show_labels(l);
}
if (cbargs.bit < 0)
puts("will clear all labels");
else
printf("will set label bit %d\n", cbargs.bit);
nl = sock_nl_create();
portid = mnl_socket_get_portid(nl);
nlh = mnl_nlmsg_put_header(buf);
nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK << 8) | IPCTNL_MSG_CT_GET;
nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP;
nlh->nlmsg_seq = seq = time(NULL);
nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
nfh->nfgen_family = AF_UNSPEC;
nfh->version = NFNETLINK_V0;
nfh->res_id = 0;
ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
if (ret == -1) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
cbargs.nl = sock_nl_create();
cbargs.seq = seq;
while (ret > 0) {
ret = mnl_cb_run(buf, ret, seq, portid, data_cb, &cbargs);
if (ret <= MNL_CB_STOP)
break;
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
}
if (ret == -1) {
perror("mnl_socket_recvfrom");
exit(EXIT_FAILURE);
}
if (l)
nfct_labelmap_destroy(l);
mnl_socket_close(nl);
return 0;
}
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