A question on modifying packet.

[Niu Zhixiong]

Sry, The problem is that I receive the packet from this NIC and send this
packet via the same NIC? Does netmap can help me?

Regards,
Niu Zhixiong
－－－－－－－－－－－－－－－
 kaiaixi at gmail.com


On Thu, Jul 10, 2014 at 1:47 AM, Sami Halabi <sodynet1 at gmail.com> wrote:

> use netgraph.
> In theory it should work.. in practice It worked for me once, but couldn't
> repeat the success.
>
> See ng_patch. Here is the code i tried:
> kldload ng_patch
> kldload ng_ipfw
> /usr/sbin/ngctl -f- << SEQ
>                  mkpeer ipfw: patch 300 in
>                  name ipfw:300 src_dst_chg
>                  msg src_dst_chg: setconfig { count=2 csum_flags=1
> ops=[         \
>                          { mode=1 value=0xc0a8e609 length=4 offset=12 }  \
>                          { mode=1 value=0xc0a8e680 length=4 offset=16 } ] }
>          SEQ
> /sbin/ipfw add 600 netgraph 300 log ip from any to 239.0.0.19 dst-port
> 1234 in via vlan999
>
> Sami
> On 7/9/14, 1:01 PM, Niu Zhixiong wrote:
>
>> Hi, all
>> I have only one NIC. I want to capture packets from one certain ip address
>> and change the both src and dst addresses and forward to other destination
>> via the same NIC. It is possible? Is there any library to help me do this?
>>
> there is no library, but look at how natd does this using divert sockets.
>
>
>>
>> Regards,
>> Niu Zhixiong
>> －－－－－－－－－－－－－－－
>>   kaiaixi at gmail.com
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