From: unobe@cpan.org
To: 9front@9front.org
Subject: Re: [9front] [PITCH] ip/null
Date: Mon, 11 Dec 2023 10:54:58 -0800 [thread overview]
Message-ID: <0C0E7B64F2E5A67D8B1525C4B2EF8C7A@smtp.pobox.com> (raw)
In-Reply-To: <fd9f3ff2-645c-9ff2-22d0-7e218dc88ed8@posixcafe.org>
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 18:56 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 [this message]
2023-12-11 19:00 ` Jacob Moody
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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