Date: Tue, 12 Jan 2010 02:29:59 +0200 From: Maxim Ignatenko <gelraen.ua@gmail.com> To: Julian Elischer <julian@elischer.org> Cc: freebsd-net@freebsd.org Subject: Re: ng_patch node Message-ID: <ac42db051001111629p118cf6e4p4adce3dc4fb90065@mail.gmail.com> In-Reply-To: <4B4BBE59.9010908@elischer.org> References: <ac42db051001111440p7b460641g855e4264d9433f58@mail.gmail.com> <4B4BBE59.9010908@elischer.org>
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2010/1/12 Julian Elischer <julian@elischer.org>:
> Maxim Ignatenko wrote:
>>
>> Hi,
>> I've written netgraph node able to modify arbitrary (8|16|32)-bit
>> unsigned integer in passing packets. Node applies one of =3D,+,-,&,| and
>> ^ operations to number at given offset.
>> Modification applied to each packet received on "in" hook. If "out"
>> hook is connected - resulting packets passed on it, otherwise -
>> returned back on "in" (for more easy use with ng_ipfw). Packets
>> received on "out" hook passed on "in" unmodified.
>> Node supports two control messages: "getconfig" and "setconfig".
>> Configuration represented in next structure:
>> struct ng_patch_config {
>> =C2=A0 =C2=A0 =C2=A0 uint32_t =C2=A0 =C2=A0 =C2=A0 =C2=A0value; /* argum=
ent passed to requested operation */
>> =C2=A0 =C2=A0 =C2=A0 uint32_t =C2=A0 =C2=A0 =C2=A0 =C2=A0offset; /* offs=
et in bytes */
>> =C2=A0 =C2=A0 =C2=A0 uint32_t =C2=A0 =C2=A0 =C2=A0 =C2=A0length; /* 1,2 =
or 4 bytes */
>> =C2=A0 =C2=A0 =C2=A0 uint32_t =C2=A0 =C2=A0 =C2=A0 =C2=A0mode; /* operat=
ion code: 1 - "=3D", 2 - "+", 3 -
>> "-", 4 - "&", 5 - "|", 6 - "^" */
>> };
>> Same names used in ASCII representation.
>>
>> I wanted to make ipfw able to modify TTL and ToS fields in IP packets,
>> but after some generalization idea looked like described above.
>
>
> I like it :-)
> if you can provide a short man page, I can commit it for you.
>
I'll try to do this in few days, thanks :)
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