Netgraph ng_patch and ng_input: where to find packets?

[Victor Gamov]

On 26Nov, 2013, at 03:57, Julian Elischer wrote:

> On 11/24/13, 5:05 AM, Victor Gamov wrote:
>> Hi All
>> 
>> I want to get 2 or 3 copies of input packet at my system to resend it to new destinations.  So I prepare following configuration:
>> 
>> # ipfw add 10000 ngtee 100 udp from any to 239.0.0.19 dst-port 1234 in via vlan999
>> 
>> # ngctl mkpeer ipfw: hub 100 hub-in
>> # ngctl name ipfw:100 hub100
>> 
>> # ngctl mkpeer hub100: patch hub100-out1 in
>> # ngctl name hub100:hub100-out1 patch100
>> # ngctl msg patch100: setconfig '{ count=1 csum_flags=1 ops=[ { value=0xc0a8e680 offset=16 length=4 mode=1 } ] }'
>> 
>> Now when I connect to patch:out as
>> # nghook -a patch100: out
>> 
>> then I see packets with new IP:
>> 
>> 0000:  45 00 05 40 00 00 40 00 ff 11 b9 27 c0 a8 0d 12
>> 0010:  c0 a8 e6 80 04 dc 04 dc 05 2c 00 00 47 4c ef 1a
>> 
>> Now I want to put this packets back into IP processing to send it to new destination 192.168.230.128 (0xc0a8e680):
>> 
>> # ngctl mkpeer patch100: ip_input out new100_to_dst_1
>> 
>> But packets not shown on outgoing interface:
>> 
>> # ifconfig vlan333
>> vlan333: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>> 	options=103<RXCSUM,TXCSUM,TSO4>
>> 	ether 00:1b:21:5b:7e:e9
>> 	inet 192.168.230.9 netmask 0xffffff00 broadcast 192.168.230.255
>> 
>> # arp 192.168.230.128
>> ? (192.168.230.128) at 62:99:4c:3b:22:fc on vlan333 expires in 1190 seconds
> I would looking at giving the packet back to the firewall as suggested..
> 
>  netgraph cookie
>             Divert packet into netgraph with given cookie.  The search termi-
>             nates.  If packet is later returned from netgraph it is either
>             accepted or continues with the next rule, depending on
>             net.inet.ip.fw.one_pass sysctl variable.
> see ng_ipfw for more details..

Yes I read this manuals :-)   But I still can't see packets neither at ipfw nor at outgoing interface.

net.inet.ip.fw.one_pass: 0
net.inet.ip.forwarding: 1

Is my original idea is correct?

--
CU,
Victor Gamov