bytes received from recvmsg doesn't match FIONREAD

I wanted to verify that the size of a multicast UDP message received with recvmsg matches the size of the message the kernel thinks the message is. So I went about using the FIONREAD ioctl as follows: res = ioctl (fd, FIONCREAD, &value); assert (res != -1); bytes_received = recvmsg (fd, &msg_recv

ipv6 SIOCGIFCONF not implemented ?

I see in ipv4/devinet.c there is a call to register_gifconf which registers a SIOCGIFCONF handler for the IPV4 protocol. There is no such registration for ipv6. As a result, SIOCGIFCONF doesn't work for ipv6. Is this intentional, or an oversight? If its an oversight, I can work up a patch to add