Use the following option to provide checksum processing for RAW applications:

IPV6_CHECKSUM (used with RAW applications)

The IPV6_CHECKSUM socket option can be used by a RAW application to enable checksum processing to be done by the TCP/IP protocol stack for packets on a socket. When enabled, the checksum is computed and stored for outbound packets; the checksum is verified for inbound packets. Note that this socket option is not applicable for ICMPv6 RAW sockets because the TCP/IP protocol stack always provides checksum processing for them.

This option can be enabled or disabled only with a setsockopt(). IPV6_CHECKSUM is not valid as ancillary data on sendmsg(). The option value provides the offset into the user data where the checksum field begins. The option value should be an even number in the range 0 - 65534. The value -1 causes the option to be disabled.

A getsockopt() with this option returns the value set by a setsockopt(). If a setsockopt() has not been done, the value -1 (disabled) is returned.