Re: [9front] [PITCH] ip/null

[hiro <23hiro@gmail.com>]

is your example more fine-grained than routing tables?
in that case i misread the example.

On 12/11/23, Jacob Moody <moody@posixcafe.org> wrote:
> Indeed, but right now ipmux is the only tool we have for doing any
> filtering more fine grained then routing tables as far as I know.
>
> I would like our own pf-like but that would require going back to
> the drawing board.
>
> On 12/11/23 13:05, hiro wrote:
>> it would be good if it wouldn't need to get all the way to userland
>> before being dropped.
>>
>> On 12/11/23, Jacob Moody <moody@posixcafe.org> wrote:
>>> This as obsoleted by cinap's aux/dial(1).
>>> It functionally works the same here except you would
>>> need an explicit direction to /dev/null.
>>>
>>> ie.
>>>
>>> aux/dial
>>> 'ipmux!ifc=my.external.ip;dst=192.168.0.0&255.255.0.0|10.0.0.0&255.0.0.0'
>>> >
>>> /dev/null
>>>
>>> On 12/11/23 12:54, unobe@cpan.org wrote:
>>>> FWIW, I haven't seen anyone else comment on this, but I like it.
>>>>
>>>> Quoth Jacob Moody <moody@mail.posixcafe.org>:
>>>>> As I play around more with 9front as my router, I found myself
>>>>> reaching
>>>>> for some
>>>>> kind of 'firewall'. I find that we already have a pretty good
>>>>> interface
>>>>> in the kernel
>>>>> in the form of ipmux. But there isn't too many ways of making use of
>>>>> it
>>>>> as is. I hacked up
>>>>> something quick to just drop packets matching a filter on to the
>>>>> floor.
>>>>> If others find it
>>>>> useful I can make up a man page and present again with a bit more
>>>>> polish.
>>>>>
>>>>> Some examples:
>>>>> # Drop inbound private range
>>>>> ip/null
>>>>> 'ifc=my.external.ip;dst=192.168.0.0&255.255.0.0|10.0.0.0&255.0.0.0'
>>>>>
>>>>> # google verboden
>>>>> ip/null 'ifc=my.internal.ip;dst=8.8.8.8;src=192.168.0.0&255.255.0.0'
>>>>>
>>>>> thanks,
>>>>> moody
>>>>>
>>>>> --- /dev/null
>>>>> +++ b//sys/src/cmd/ip/null.c
>>>>> @@ -1,0 +1,36 @@
>>>>> +#include <u.h>
>>>>> +#include <libc.h>
>>>>> +
>>>>> +void
>>>>> +usage(void)
>>>>> +{
>>>>> +	fprint(2, "usage: %s filter\n", argv0);
>>>>> +	exits("usage");
>>>>> +}
>>>>> +
>>>>> +void
>>>>> +main(int argc, char **argv)
>>>>> +{
>>>>> +	char buf[64 * 1024];
>>>>> +	int fd;
>>>>> +
>>>>> +	ARGBEGIN{
>>>>> +	default:
>>>>> +		usage();
>>>>> +		break;
>>>>> +	}ARGEND
>>>>> +	if(argc < 1)
>>>>> +		usage();
>>>>> +
>>>>> +	fd = dial(smprint("ipmux!%s", argv[0]), nil, nil, nil);
>>>>> +	if(fd < 0)
>>>>> +		sysfatal("dial: %r");
>>>>> +
>>>>> +	for(;;)
>>>>> +		switch(read(fd, buf, sizeof buf)){
>>>>> +		case -1:
>>>>> +			sysfatal("read: %r");
>>>>> +		case 0:
>>>>> +			return;
>>>>> +		}
>>>>> +}
>>>>
>>>
>>>
>
>