hi Micha,
What exatly i want that each IP,TCP,ICMP packet that goes out of machine should include my own 8 byte data checksum that i want to include along with total packet at Ip layer.
what it helps? It helps to know other computer that somebody has changed data in packet which doesnot have any checksum at Ip layer.
I think you will now understand what i want to do ? Now whatever i ask you uptill now is related with same but considering only ICMP implementation.
regards,
parag.
On Sat, 15 May 2004 Micha Feigin wrote :
>On Fri, May 14, 2004 at 10:10:38AM -0000, bunty wrote:
> >
> > hi Michia,
> > so i have to implement a new protocol in between ICMP and IP
> > protocol. so for that i have to implement a function that takes control from
> > ICMP and gives to IP layer. but still dont you feel that there should be
> > problem again of space. Because how does it knoes total space to be alloacted
> > for packet with new protocol layer.
> > regards,
> > parag.
> >
>
>You would actually want to implement a protocol that sits above ICMP,
>since your protocol will be aware of ICMP, but not the other way
>around.
>
>Your protocol would implement a new socket type so the entry function
>would be in your protocol, it would add its header and then send call
>ICMP to handle the data further.
>
>I am not sure though how to get incoming packets to pass through your
>protocol handler. You should probably look at the specs or the code for
>incoming packets to see how the kernel is aware of the next protocol
>layer, you may need to modify the ICMP code for that.
>
>Any reason why you want this in kernel space and not user space?
>
> >
> > On Thu, 13 May 2004 Micha Feigin wrote :
> > >On Thu, May 13, 2004 at 07:21:25AM -0000, bunty wrote:
> > > >
> > > > hi,
> > > > i acually increase icmp header length but when i build kernel i
> > > > am getting iph hook: happy cracking which is because of ip packet
> > > > header is not completely add to skb so its iphdr's len became short
> > > > for that i want to know where should i change the space allocated for
> > > > packet i change the same sock_alloc_send_skb length by the value i
> > > > want it should be increased?
> > > >
> > >
> > >I'm afraid I don't know the answer to that. Some googling seems to show
> > >that icmp is part of IP so you may have to enlarge the size of the IP
> > >header to allow for the extra data or maybe play with the value of
> > >skb->nh.iph.
> > >
> > >You should look at the specs first to see if they allow that though.
> > >
> > >I think the right (although maybe not the easiest) method is to add
> > >another protocol layer either at the level of tcp/ip (level 4 i think)
> > >or above them, depending on where you want the data.
> > >
> > >Try having a look for example at:
> > >http://www.freesoft.org/CIE/Course/Section3/7.htm
> > >http://www.onlamp.com/pub/a/bsd/2001/04/04/FreeBSD_Basics.html
> > >http://www.freesoft.org/CIE/Course/Section3/index.htm
> > >
> > >
> > > > regards,
> > > > parag.
> > > >
> > > >
> > > > _[_h_t_t_p_:_/_/_a_d_s_._r_e_d_i_f_f_._c_o_m_/
> > _R_e_a_l_M_e_d_i_a_/_a_d_s_/
> > _a_d_s_t_r_e_a_m___n_x_._c_g_i_/
> > _w_w_w_._r_e_d_i_f_f_m_a_i_l_._c_o_m_/
> > > > _i_n_b_o_x_._h_t_m_@_B_o_t_t_o_m_]
> > > > +++++++++++++++++++++++++++++++++++++++++++
> > > > This Mail Was Scanned By Mail-seCure System
> > > > at the Tel-Aviv University CC.
> >
> >
> > _[_h_t_t_p_:_/_/_a_d_s_._r_e_d_i_f_f_._c_o_m_/_R_e_a_l_M_e_d_i_a_/_a_d_s_/_a_d_s_t_r_e_a_m___n_x_._c_g_i_/_w_w_w_._r_e_d_i_f_f_m_a_i_l_._c_o_m_/
> > _i_n_b_o_x_._h_t_m_@_B_o_t_t_o_m_]
> > +++++++++++++++++++++++++++++++++++++++++++
> > This Mail Was Scanned By Mail-seCure System
> > at the Tel-Aviv University CC.
>
>--
>Kernelnewbies: Help each other learn about the Linux kernel.
>Archive: http://mail.nl.linux.org/kernelnewbies/
>FAQ: http://kernelnewbies.org/faq/
>
