nic_bridge DHCP problem

Markus Partheymueller mail at ...119...
Fri Sep 14 14:38:24 CEST 2012

Hey folks,

I'm having some trouble with the nic_bridge provided. When using the
nic_drv as single instance, everything works fine.

But when I replace it with the nic_bridge, the requests don't seem to
make it through. In qemu's TCP dump, I recognized a difference
regarding the DHCP broadcast:

13:08:25.494579 IP (tos 0x0, ttl 64, id 5118, offset 0, flags [none],
proto UDP (17), length 341) > [bad udp cksum 0x9134 -> 0xd233!]
BOOTP/DHCP, Request from 02:02:02:02:02:02, length 313, xid
0x292e1940, Flags [Broadcast] (0x8000)
          Client-Ethernet-Address 02:02:02:02:02:02
          Vendor-rfc1048 Extensions
            Magic Cookie 0x63825363
            DHCP-Message Option 53, length 1: Discover
            MSZ Option 57, length 2: 1500
            Vendor-Class Option 60, length 42:
"dhcpcd-5.2.7:Linux-3.5.0:i686:NOVA microHV"
            Hostname Option 12, length 2: "vm"
            Parameter-Request Option 55, length 15:
              Subnet-Mask, Classless-Static-Route, Static-Route, Default-Gateway
              Domain-Name-Server, Hostname, Domain-Name, MTU
              BR, NTP, Lease-Time, Server-ID
              RN, RB, Option 119

The bad checksum irritated me. When I used the nic_drv session, it
worked (checksum OK, qemu's DHCP responds correctly with an IP
address). Could there be a problem with the bridge itself or is it
definitely my problem? Do you have example setups using the bridge
that work?



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