Some embodiments provide a method for sending data messages at a network interface controller (NIC) of a computer. From a network stack executing on the computer, the method receives (i) a header for a data message to send and (ii) a logical memory address of a payload for the data message. The method translates the logical memory address into a memory address for accessing a particular one of multiple devices connected to the computer. The method reads payload data from the memory address of the particular device. The method sends the data message with the header received from the network stack and the payload data read from the particular device.