1. A method, comprising: receiving, at an intermediate node in a computer network, one or more reactive routing route requests (RREQs) from an originating node; building, based on the RREQs, a first directed acyclic graph (DAG) in the computer network rooted at the originating node; forwarding the RREQs toward a target node; receiving, at the intermediate node, one or more reactive routing route replies (RREPs) from the target node; building, based on the RREPs, a second DAG in the computer network rooted at the target node; and forwarding the RREPs toward the originating node.