where is the source code for interrupt handler for linux kernel?

[hemanth]

A network device driver can notify the kernel about packet reception using interrupts. This can be done after every received packets or after receiving a specified number of packets. I am looking for source code of interrupt service routine in the linux kernel. I want to modify interrupt service routine as - I should calculate the timestamp when the interrupt occurs. later Received packets by the network driver are enqued by the kernel queue handler and I want to store the timestamp in sk_buff data structure is used to store information about the packets enqueued.

So please someone help where is the location for the interrupt handler code of linux kernel ??
how to store the timestamp in sk_buff data structure ??