conntrack module development problem

[Brad Chapman]

Mr. Shore,

   Change the helper init function to read like this:

   int ret;

   /* rest of function */

   ret = ip_conntrack_helper_register(&icq);
   if (ret < 0) {
       DEBUGP("KABOOM! Aiee, I'm not in!\n");        ;-)
       return ret;
   }
   DEBUGP("Ahhh, I'm in at last\n");                 ;-)

   Maybe you have bugs initializing the helper; this will detect that. If it
works, then you initialized it incorrectly in some fashion. BTW will 
this actually
become a `real' conntrack helper for ICQ? IIRC, no one else has worked 
on it.....

Brad

S. Shore wrote:

> Hi!
> 
> I'm trying to make a new conntrack module, but it doesn't seem to be
> receiving packets that I've set the tuple for.  See code below.
> 
> As you can see, at this point it's very similar to the sample code in the
> netfilter howtos, and it compiles cleanly. I've included the compile
> options specified at the end of the source. It's not supposed to do
> anything useful yet, just print debug messages.
> 
> It should printk an "ICQ packet received" whenever an icq packet goes by,
> but it doesn't. It does print the "I'm in!" and "I'm out!" printk's at
> module load and release, though.
> 
> What am I missing here? Any assistance would be greatly appreciated.
> 
> Cheers,
> Scott <sshore@escape.ca>
> 
> 
> 
> #include <linux/version.h>
> #include <linux/module.h>
> #include <linux/netfilter.h>
> #include <linux/ip.h>
> #include <linux/ctype.h>
> #include <net/checksum.h>
> #include <net/udp.h>
> #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
> 
> #define ICQ_PORT 4000
> #define DEBUGP(format, args...) printk(KERN_DEBUG __FILE__ ":" __FUNCTION__ \
> 				":" format, ## args)
> 
> static int icq_help(const struct iphdr *iph, size_t len,
> 			struct ip_conntrack *ct,
> 			enum ip_conntrack_info ct_info)
> {
> 	DEBUGP("ICQ packet received\n");
> 
> 	return NF_ACCEPT;
> }
> 
> static struct ip_conntrack_helper icq;
> 
> static int __init init(void)
> {
> 	memset(&icq, 0, sizeof(struct ip_conntrack_helper));
> 
> 	icq.tuple.dst.protonum = IPPROTO_UDP;
> 	icq.tuple.dst.u.udp.port = htons(ICQ_PORT);
> 	icq.mask.dst.protonum = 0xFFFF;
> 	icq.mask.dst.u.udp.port = 0xFFFF;
> 	icq.help = icq_help;
> 
> 	DEBUGP("I'm in!\n");
> 
> 	return ip_conntrack_helper_register(&icq);
> }
> 
> static void __exit fini(void)
> {
> 	DEBUGP("I'm out!\n");
> 	ip_conntrack_helper_unregister(&icq);
> }
> 
> module_init(init);
> module_exit(fini);
> 
> /* gcc -D__KERNEL__ -I/usr/src/linux/include -Wall -Wstrict-prototypes -O2
> -fomit-frame-pointer -fno-strict-aliasing -pipe -march=i486 -DMODULE -c -o
> test.o test.c */
> 
> 
> 
>