Inside Macintosh: Networking With Open Transport / Part 2 - Open Transport Reference

Chapter 29 - TCP/IP Services Reference / Options

UDP Options

You can use the options in this section with a protocol level of INET_UDP. The UDP_CHECKSUM option is association-related. It may be negotiated in all endpoint states except T_UNBND and T_UNINIT. It is read-only in state T_UNBND. The UDP_RX_ICMP option is read-only in all states.

#define UDP_CHECKSUM    OPT_CHECKSUM   /
#define UDP_RX_ICMP     0x2            

Option descriptions

UDP_CHECKSUM

Activate or deactivate a checksum calculation. (UInt32)

Specify T_YES to activate the checksum calculation or T_NO to deactivate it. The default value for this option is T_YES. If this option is returned by the OTRcvUData function, its value indicates whether a checksum was present in the received datagram. UDP discards packets that do not have valid checksums when this option is activated. UDP relies on checksum calculations to provide reliable data delivery; under normal circumstances, you should never deactivate this option. A request to activate or deactivate checksums is an absolute requirement.

UDP_RX_ICMP

Determine whether the UDP STREAMS module has received an ICMP message. This option returns a Boolean value.