k5_size_address
k5_size_address(krb5_address *address, size_t *sizep);
kret = k5_size_address(auth_context->remote_addr, &required);
kret = k5_size_address(auth_context->remote_port, &required);
kret = k5_size_address(auth_context->local_addr, &required);
kret = k5_size_address(auth_context->local_port, &required);
if (!k5_size_address(address, &required) && required <= remain) {