From: Jacob Moody <moody@posixcafe.org>
To: 9front@9front.org
Subject: Re: [9front] [PITCH] ip/null
Date: Mon, 11 Dec 2023 13:00:47 -0600 [thread overview]
Message-ID: <d806068d-f846-4880-8e01-bbe30f492720@posixcafe.org> (raw)
In-Reply-To: <0C0E7B64F2E5A67D8B1525C4B2EF8C7A@smtp.pobox.com>
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;
>> + }
>> +}
>
next prev parent reply other threads:[~2023-12-11 19:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 3:42 Jacob Moody
2023-12-11 18:54 ` unobe
2023-12-11 19:00 ` Jacob Moody [this message]
2023-12-11 19:05 ` hiro
2023-12-11 19:11 ` Jacob Moody
2023-12-11 19:17 ` hiro
2023-12-11 19:22 ` Jacob Moody
2023-12-11 19:32 ` hiro
2023-12-11 19:45 ` unobe
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