There exist several applications of sensor networks where reliability of data delivery can be critical. While the redundancy inherent in a sensor network might increase the degree of reliability, it by no means can provide any strict reliability semantics. In this paper, we focus on the problem of delivering information with strict reliability semantics, from the sink to the sensors in a sensor field. We identify different types of reliability semantics that might be required by sensor applications, for delivery of both queries and larger pieces of information such as code segments for re-configurable sensors. We propose a generic framework called GARUDA that is highly scalable, dynamically self-configurable, and instantaneously constructible. It leverages the unique characteristics of sensor network environments effectively, thus incurring low overheads. We show that GARUDA can flexibly support the different classes of reliability semantics. Through ns2 based simulations, we evaluate the GARUDA framework with that of existing approaches, and show that it performs significantly better over a wide variety of network conditions.