ethernet checksum offloading
Hello everyone,
I have a question concerning the Ethernet Card of the 2.4GHz MBP and which features are of it are supported by OS X. I would need to enable/disable Checksum offloading. It seems like this is enabled by default in the kernel. But as I want to receive some UDP packets from an embedded device which do not have a UDP checksum (this is allowed per the RFC for IPV4 UDP) this seems to be blocking the reception as i can't access the data via a socket and recvfrom() calls nor see any indication of the packets with netstat, though they are definitely sent to the machine (they are visible and correct in a packet-sniffer like ethereal). And it must be due to the missing checksum as I can receive packets with the checksum implemented.
In FreeBSD one can change the checksum offloading settings with ifconfig, but the OS X version of ifconfig doesn't provide this option. So I would like to know if there is any other way of setting this or if this is not supported. If it isn't, then I think this behavior is a bug of OS X, as the packets clearly should be passed on and not be filtered out the level of the NIC, as they are clearly valid packets and fully adhere to all standards.
michael
I have a question concerning the Ethernet Card of the 2.4GHz MBP and which features are of it are supported by OS X. I would need to enable/disable Checksum offloading. It seems like this is enabled by default in the kernel. But as I want to receive some UDP packets from an embedded device which do not have a UDP checksum (this is allowed per the RFC for IPV4 UDP) this seems to be blocking the reception as i can't access the data via a socket and recvfrom() calls nor see any indication of the packets with netstat, though they are definitely sent to the machine (they are visible and correct in a packet-sniffer like ethereal). And it must be due to the missing checksum as I can receive packets with the checksum implemented.
In FreeBSD one can change the checksum offloading settings with ifconfig, but the OS X version of ifconfig doesn't provide this option. So I would like to know if there is any other way of setting this or if this is not supported. If it isn't, then I think this behavior is a bug of OS X, as the packets clearly should be passed on and not be filtered out the level of the NIC, as they are clearly valid packets and fully adhere to all standards.
michael
MacBook Pro 2.4GHz, Mac OS X (10.4.10)