bpf-packet-tracer

A BPF program to trace the per-packet invocation of many important functions in the kernel network stack. Currently, it only traces UDP packets (which may be encapsulated by a VXLAN overlay).

To differentiate between different packets, the sender must set the first 32 bits of the UDP payload as the packet ID.

Setup

Set proper values to the constants at the top of packet_tracer.c such as:

• SHOST (IP address of source host)
• DHOST (IP address of destination host)
• SIP (IP address of source overlay interface)
• DIP (IP address of destination overlay interface)
• VXLAN_PORT (default = standard = 4789)
• UDP_PORT (UDP port number)

Run

sudo ./run.py

Example output

     TIME(s) EVENT                DEVICE           NAMESPACE  SRC             DST             PACKET ID 
     ------- -----                ------           ---------  ---             ---             ---------
  8400969.39 do_softirq          
  8400981.13 net_rx_action       
  8400985.59 ixgbe_poll                            64        
  8401717.50 do_softirq          
  8401729.60 net_rx_action       
  8401734.22 ixgbe_poll                            64        
  8401820.52 do_softirq          
  8401824.76 net_rx_action       
  8401828.08 ixgbe_poll                            64        
  8403754.32 ip_send_skb         
  8403791.80 ip_local_out        
  8403831.27 dev_queue_xmit       eno1             4026532056 192.168.0.8     192.168.0.7     0         
  8403846.32 net_dev_queue        eno1             4026532056 192.168.0.8     192.168.0.7     0         
  8403864.75 ixgbe_xmit_frame     eno1             4026532056 192.168.0.8     192.168.0.7     0         
  8403879.72 net_dev_xmit         eno1             4026532056 192.168.0.8     192.168.0.7     0         
  8403898.77 ip_send_skb         
  8403924.68 ip_local_out        
  8403952.61 dev_queue_xmit       eno1             4026532056 192.168.0.8     192.168.0.7     1         
  8403965.26 net_dev_queue        eno1             4026532056 192.168.0.8     192.168.0.7     1         
  8403978.39 ixgbe_xmit_frame     eno1             4026532056 192.168.0.8     192.168.0.7     1         
  8403990.41 net_dev_xmit         eno1             4026532056 192.168.0.8     192.168.0.7     1         
  8404021.20 do_softirq          
  8404043.40 ip_send_skb         
  8404069.08 ip_local_out        
  8404096.65 dev_queue_xmit       eno1             4026532056 192.168.0.8     192.168.0.7     2         
  8404108.43 net_dev_queue        eno1             4026532056 192.168.0.8     192.168.0.7     2         
  8404121.53 ixgbe_xmit_frame     eno1             4026532056 192.168.0.8     192.168.0.7     2         
  8404134.03 net_dev_xmit         eno1             4026532056 192.168.0.8     192.168.0.7     2         
  8404150.55 ip_send_skb         
  8404176.51 ip_local_out        
  8404204.10 dev_queue_xmit       eno1             4026532056 192.168.0.8     192.168.0.7     3         
  8404215.48 net_dev_queue        eno1             4026532056 192.168.0.8     192.168.0.7     3         
  8404228.35 ixgbe_xmit_frame     eno1             4026532056 192.168.0.8     192.168.0.7     3         
  8404240.46 net_dev_xmit         eno1             4026532056 192.168.0.8     192.168.0.7     3         
  8404256.44 ip_send_skb         
  8404282.07 ip_local_out        
  8404309.07 dev_queue_xmit       eno1             4026532056 192.168.0.8     192.168.0.7     4         
  8404320.45 net_dev_queue        eno1             4026532056 192.168.0.8     192.168.0.7     4         
  8404333.16 ixgbe_xmit_frame     eno1             4026532056 192.168.0.8     192.168.0.7     4         
  8404345.53 net_dev_xmit         eno1             4026532056 192.168.0.8     192.168.0.7     4
  ...