Re: libnet_write

Hi Amit,
as i understand it libnet_write_raw_ipv4() is part of the libnet functions 
but for internal usage(like many others). Many functions from libnet 0.x.x.x 
are used indirectly in the current 1.x.x.x but they are hidden internally. 
If you check the source code you will notice this.

So to answer your question.....yes, libnet_write_raw_ipv4() can be used 
directly to write a packet, but you won't have all the nice checks nor the 
statistics stored in the libnet handle "l" like if you use 
libnet_adv_write_raw(). for consistency I would rather use the latter.

Although I have to admit that i use the libnet_do_checksum() fn. directly, 
which is part of the 0.x.x.x ver. originally, but it is used in the current 
1.x.x.x internally to calculate the checksums when you for example set the 
checksum field of libnet_build_tcp() to ZERO.

I hope it is clearer for you now.

Regards,
Mustaffa Abu Sedira


>From: [email protected]
>To: "Mustafa Abu Sedera" <[email protected]>
>CC: [email protected], [email protected], [email protected]
>Subject: Re: libnet_write
>Date: Tue, 8 Jun 2004 21:51:36 +0530
>
>
>
>
>
>Hi Mustafa,
>
>    Yes I saw that libnet_write_raw_ipv4 is used in your function, but as
>you said it is not part of 1.1.2.1, then how did it work ? thats confusing
>?? So if this worked, then we can use libnet_write_raw_ipv4 directly also,
>right ?
>
>thanks
>Amit
>
>
>
>
>"Mustafa Abu Sedera" <[email protected]> on 06/08/2004 09:54:35 PM
>
>To:    Amit Kumar Singh/HSS@HSS
>cc:    [email protected], [email protected], [email protected]
>
>Subject:    Re: libnet_write
>
>
>
>Hi,
>libnet_write_raw_ipv4 is an official function in the old libnet API 0.x.x.x
>not in 1.x.x.x. But if you look carefully in the code you can see that it
>is
>used. I used this libnet_adv_write_raw with libnet 1.1.2 and it worked
>without problems.
>
>Regards,
>Mustaffa Abu Sedira
>
> >From: [email protected]
> >To: "Mustafa Abu Sedera" <[email protected]>
> >CC: [email protected], [email protected], [email protected]
> >Subject: Re: libnet_write
> >Date: Tue, 8 Jun 2004 20:45:45 +0530
> >
> >
> >
> >
> >
> >thanks mustafa,
> >
> >   I havent been able to try it out because of time. Just one question,
> >agreed libnet_adv_write_raw is not an official function, but
> >libnet_write_raw_ipv4 is an official libnet function, right ? and which
> >libnet version are we talking of ?, is libnet_write_ipv4 available in
> >libnet 1.1.2.1, because I use thie version , and I believe this is the
> >latest.
> >
> >regards,
> >Amit
> >
> >
> >
> >
> >"Mustafa Abu Sedera" <[email protected]> on 06/08/2004 08:40:40 PM
> >
> >To:    Amit Kumar Singh/HSS@HSS, [email protected]
> >cc:    [email protected], [email protected]
> >
> >Subject:    Re: libnet_write
> >
> >
> >
> >Hi,
> >like I wrote before.....if you don't want do build the eth hdr you can 
>use
> >libnet_adv_write_raw().
> >This is nto an "official" function in libnet. I modified the
> >libnet_adv_write_link() so that it injects the packet to the kernel which
> >takes care of the eth hdr because i needed it in a program.
> >You just copy and paste the code at the beginning of your program or in a
> >header file then use it like an ordinary libnet function.
> >I suggested before to add it to the libnet API but didn't get any
>feedback.
> >Please try it out as it made my job much easier.
> >here it is again if you have deleted the previous email:
> >
> >int
> >libnet_adv_write_raw(libnet_t *l, u_int8_t *packet, u_int32_t len)
> >{
> >     u_int c;
> >
> >     if (l == NULL)
> >     {
> >         return (-1);
> >     }
> >
> >     /* assume error */
> >     c = -1;
> >
> >     switch (l->injection_type)
> >     {
> >         case LIBNET_RAW4_ADV:
> >             if (len > LIBNET_MAX_PACKET)
> >             {
> >                 snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
> >                         "%s(): packet is too large %d\n", __func__, 
>len);
> >                 return (c);
> >             }
> >             c = libnet_write_raw_ipv4(l, packet, len);
> >             break;
> >
> >         case LIBNET_RAW6_ADV:
> >             c = libnet_write_raw_ipv6(l, packet, len);
> >             break;
> >
> >         default:
> >             snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
> >                 "%s(): advanced raw mode not enabled\n", __func__);
> >             return (-1);
> >     }
> >
> >     /* do statistics */
> >     if (c == len)
> >     {
> >         l->stats.packets_sent++;
> >         l->stats.bytes_written += c;
> >     }
> >     else
> >     {
> >         l->stats.packet_errors++;
> >         /*
> >          *  XXX - we probably should have a way to retrieve the number 
>of
> >          *  bytes actually written (since we might have written
> >something).
> >          */
> >         if (c > 0)
> >         {
> >             l->stats.bytes_written += c;
> >         }
> >     }
> >
> >     return (c);
> >}
> >To describe the function again....
> >You pass a pointer "packet" which would point to the ip header of a 
>packet
> >with length "len" (total IP packet length without the eth hdr) and it
> >writes
> >the packet to libnet handle "l".
> >
> >Regards,
> >Mustaffa Abu Sedira
> >
> >
> > >From: [email protected]
> > >To: Aaron Turner <[email protected]>
> > >CC: "Jee J.Z." <[email protected]>, [email protected]
> > >Subject: Re: libnet_write
> > >Date: Mon, 7 Jun 2004 10:01:44 +0530
> > >
> > >
> > >
> > >
> > >
> > >Hi,
> > >
> > >   What if I do not want to build the ethernet header. I want the 
>packet
> >to
> > >be a raw packet that is handed to ip after the write call. What about
> > >libnet_write_raw_ipv4, i tihink that is no longer supported, i use
>libnet
> > >1.1.2.1.
> > >  Mustafa talked about libnet_write_raw_ipv4, but I can't finds that in
> >my
> > >help either, such a function exists ?
> > >
> > >thanks
> > >Amit
> > >
> >
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