Netgraph - Breaks "ping"

[Len Gross]

I'm trying to "monitor" an ethernet interface with a tee node, but ping
breaks when I setup the graph.  I suspect I'm doing something "dumb" with
respect to how the Ethernet node and/or  the iface (ng0) need to be
configured in order to make this work, or possibly I'm really using ng0
incorrectly.  (I've also tried this with a "direct connect" of rl0: to ng0:
which also doesn't work.)



Before Netgraph

  Machine Setup

  Machine 1 192.168.4.1

  Machine 2: 192.168.4.4 (rl0)

  Machine 1 can ping machine 2 going through rl0



BSD-1# ifconfig rl0

rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500

        options=8<VLAN_MTU>

        inet6 fe80::248:54ff:fe8b:1cc8%rl0 prefixlen 64 scopeid 0x3

        inet 192.168.4.4 netmask 0xffffff00 broadcast 192.168.4.255

        ether 00:48:54:8b:1c:c8

        media: Ethernet autoselect (100baseTX <full-duplex>)

        status: active



Now on Machine 2, I set up netgraph:



Kldload ng_ether



Using ngctl to create a path from rl0: to tee: to ng0:

Here is the list and show output.



There are 6 total nodes:

  Name: ng0                   Type: iface           ID: 00000008   Num
hooks: 1

  Name: tee                   Type: tee                    ID: 00000007   Num
hooks: 4

  Name: rl0                   Type: ether           ID: 00000004   Num
hooks: 1

  Name: wi0                  Type: ether           ID: 00000003   Num hooks:
0

  Name: xl0                    Type: ether           ID: 00000002   Num
hooks: 0

  Name: ngctl681           Type: socket          ID: 00000001   Num hooks: 2



+ show tee:

  Name: tee             Type: tee             ID: 00000007   Num hooks: 4

  Local hook      Peer name       Peer type    Peer ID         Peer hook


  ----------      ---------       ---------    -------         ---------


  left2right      ngctl681        socket       00000001        upper


  left                   ng0             iface        00000008
inet


  right                rl0             ether        00000004
lower


  right2left      ngctl681        socket       00000001        lower



+ show rl0:

  Name: rl0             Type: ether           ID: 00000004   Num hooks: 1

  Local hook      Peer name       Peer type    Peer ID         Peer hook


  ----------      ---------       ---------    -------         ---------


  lower           tee             tee          00000007        right



+ show ng0:

  Name: ng0             Type: iface           ID: 00000008   Num hooks: 1

  Local hook      Peer name       Peer type    Peer ID         Peer hook


  ----------      ---------       ---------    -------         ---------


  inet            tee             tee          00000007        left






Now I use machine 1 to ping machine 2 and here is what I get on the ngctl
screen.



Rec'd data packet on hook "lower":

0000:  00 48 54 8b 1c c8 00 02 3f 8a d6 44 08 00 45 00  .HT.....?..D..E.

0010:  00 3c 02 19 00 00 80 01 af 52 c0 a8 04 01 c0 a8  .<.......R......

0020:  04 04 08 00 2a 5c 02 00 21 00 61 62 63 64 65 66  ....*\..!.abcdef

0030:  67 68 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76  ghijklmnopqrstuv

0040:  77 61 62 63 64 65 66 67 68 69                    wabcdefghi



This looks kind-of right, but I don't get anything back from the ng0 node (
i.e no other output to ngctl.)  Also, machine 1 "times out" its ping.



BSD-1# ifconfig ng0

ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1500

        inet6 fe80::201:3ff:fe24:ffe3%ng0 prefixlen 64 scopeid 0x6



I've also tried giving ng0 inet addresses, but got the same results.



Help!



-- Len