[lwip-users] Problems with testing lwip on FreeBSD

[Henk Dijkstra]

I have a problem with testing LWIP (1.1.0) with the unix simhost program
on FreeBSD 5.3 wich seems not related
to lwip, but with the working of the tap0 Interface.

   System 1:
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 10.15.47.115 netmask 0xfffff000 broadcast 10.15.47.255
        inet6 fe80::204:75ff:fef8:5f08%xl0 prefixlen 64 scopeid 0x1
        ether 00:04:75:f8:5f:08
        media: Ethernet autoselect (10baseT/UTP)
        status: active


   System 2:
   This system also runs lwip:
   IP4_ADDR(&gw,10,15,46,199)
   IP4_ADDR(&ipaddr,10,15,46,200)
   IP4_ADDR(&netmask,255,255,255,0)

   so ifconfig shows:
bge0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu
1500
        options=1a<TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
        inet 10.15.47.238 netmask 0xfffff000 broadcast 10.15.47.255
        inet6 fe80::20b:cdff:fef3:d40c%bge0 prefixlen 64 scopeid 0x1
        ether 00:0b:cd:f3:d4:0c
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
tap0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu
1500
        inet6 fe80::2bd:25ff:fe73:8600%tap0 prefixlen 64 scopeid 0x4
        inet 10.15.46.199 netmask 0xffffff00 broadcast 10.15.46.255
        ether 00:bd:25:73:86:00
        Opened by PID 34228

When I ping from system 1 to 10.15.46.200 (the simhost app) and look at
the tap0 traffic on System 2:

15:33:13.393676 IP 10.15.47.115 > 10.15.46.200: icmp 64: echo request
seq 60674
        0x0000:  4500 0054 d1b2 0000 4001 369e 0a0f 2f73
address@hidden/s
        0x0010:  0a0f 2ec8 0800 46e4 0fb1 ed02 27a2 b243
......F.....'..C
        0x0020:  ec7e 0300 0809 0a0b 0c0d 0e0f 1011 1213
.~..............
        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223
.............!"#
        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233
$%&'()*+,-./0123
        0x0050:  3435 3637                                4567
15:33:13.394016 IP 10.15.46.200 > 10.15.47.115: icmp 64: echo reply seq
60674
        0x0000:  4500 0054 d1b2 0000 4001 369e 0a0f 2ec8
address@hidden
        0x0010:  0a0f 2f73 0000 4ee4 0fb1 ed02 27a2 b243
../s..N.....'..C
        0x0020:  ec7e 0300 0809 0a0b 0c0d 0e0f 1011 1213
.~..............
        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223
.............!"#
        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233
$%&'()*+,-./0123
        0x0050:  3435 3637                                4567

Everything looks alright, however on the bge0 interface the reply from
lwip is missing:

15:34:42.268409 IP 10.15.47.115 > 10.15.46.200: icmp 64: echo request
seq 17667
        0x0000:  4500 0054 d20a 0000 4001 3646 0a0f 2f73
address@hidden/s
        0x0010:  0a0f 2ec8 0800 f4d9 0fb1 4503 80a2 b243
..........E....C
        0x0020:  8f88 0100 0809 0a0b 0c0d 0e0f 1011 1213
................
        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223
.............!"#
        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233
$%&'()*+,-./0123
        0x0050:  3435 3637                                4567
15:34:43.278318 IP 10.15.47.115 > 10.15.46.200: icmp 64: echo request
seq 17923
        0x0000:  4500 0054 d20b 0000 4001 3645 0a0f 2f73
address@hidden/s
        0x0010:  0a0f 2ec8 0800 4fb3 0fb1 4603 81a2 b243
......O...F....C
        0x0020:  32af 0100 0809 0a0b 0c0d 0e0f 1011 1213
2...............
        0x0030:  1415 1617 1819 1a1b 1c1d 1e1f 2021 2223
.............!"#
        0x0040:  2425 2627 2829 2a2b 2c2d 2e2f 3031 3233
$%&'()*+,-./0123
        0x0050:  3435 3637                                4567

It looks like FreeBSD doesn't want to route the outgoing traffic from
the tap0 interface to the physical bge0 interface.
(I also tried a direct ping to System 1, from withing simhost, but these
messages don't show up on the bge0 interface neither.  Anyone with
experience on FreeBSD got some hints?

Regards,

Henk Dijkstra