Hi,
I'm a new user to libnetfilter_queue. I ran the test example of
libnetfilter_queue-1.0.0 on a Debian x86 (Linux debian 2.6.26-1-686)
host but I found that the pakcets queue in NFQUEUE were not dequeued
after recv() was invoked. I ran the iptables command on the debain host:
iptables -A INPUT -p udp --dport 8192:32000 -j NFQUEUE --queue-num 0
Then I send UDP packets from another machine with destination port in
the range. By default, the libnetfilter_queue received 1000 packets on
Debian host and stopped (blocked in recv()). Then I set the queue length
to 12000 nfq_set_queue_maxlen(qh, 1200) . This time, the
libnetfilter_queue received 1200 packets and stopped (blocked in
recv()).
Looks like the pakcets were not dequeued from NFQUEUE? How can I fix
this problem?
int main(int argc, char **argv)
{
struct nfq_handle *h;
struct nfq_q_handle *qh;
struct nfnl_handle *nh;
int fd;
int rv;
char buf[4096] __attribute__ ((aligned));
printf("opening library handle\n");
h = nfq_open();
if (!h) {
fprintf(stderr, "error during nfq_open()\n");
exit(1);
}
printf("unbinding existing nf_queue handler for AF_INET (if
any)\n");
if (nfq_unbind_pf(h, AF_INET) < 0) {
fprintf(stderr, "error during nfq_unbind_pf()\n");
exit(1);
}
printf("binding nfnetlink_queue as nf_queue handler for
AF_INET\n");
if (nfq_bind_pf(h, AF_INET) < 0) {
fprintf(stderr, "error during nfq_bind_pf()\n");
exit(1);
}
printf("binding this socket to queue '0'\n");
qh = nfq_create_queue(h, 0, &cb, NULL);
if (!qh) {
fprintf(stderr, "error during nfq_create_queue()\n");
exit(1);
}
printf("setting copy_packet mode\n");
if (nfq_set_mode(qh, NFQNL_COPY_PACKET, 0xffff) < 0) {
fprintf(stderr, "can't set packet_copy mode\n");
exit(1);
}
if (nfq_set_queue_maxlen(qh, 1200) < 0) {
fprintf(stderr, "can't set queue_maxlen\n");
exit(1);
}
fd = nfq_fd(h);
while ((rv = recv(fd, buf, sizeof(buf), 0)) && rv >= 0) {
nfq_handle_packet(h, buf, rv);
}
printf("unbinding from queue 0\n");
nfq_destroy_queue(qh);
#ifdef INSANE
/* normally, applications SHOULD NOT issue this command, since
* it detaches other programs/sockets from AF_INET, too ! */
printf("unbinding from AF_INET\n");
nfq_unbind_pf(h, AF_INET);
#endif
printf("closing library handle\n");
nfq_close(h);
exit(0);
}
Best regards
===========================
Mai Jin
Alcatel Shanghai Bell (Nanjing) Co. Ltd.
Alcatel-Net: 2735-5011
Tel: (+86)-25-8473 1240-5011
Addr: 11F, Yangtse River Tech Park.
Building No.40 of Nanchang Road,
Gulou District, Nanjing, China
Zip: 210037
jin.mai@xxxxxxxxxxxxxxxxxxxx
ASB/MoAD/RDR/BSR APL
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