ovs-dptrace

README

ovs-dptrace

OpenvSwitch kernel datapath tracing tool based on ebpf. It helps visualize actions and upcalls made by the kernel datapath.

Features

• CO-RE single binary
• L2, L3, L4 header filtering
• Save samples for offline processing

Requirements

• Linux kernel >= 1.14 (asuming the in-tree openvswitch kernel module is used)

Build

make

Build requirements

• bpftool
• golang

Usage

Visualize life events:

ovs-dptrace -filter 'proto tcp'
666700664705504 | p2_l UPCALL: TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xe6f1beaf
666700665288097 | p2_l ACTION (HASH): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xe6f1beaf
666700665313641 | p2_l ACTION (RECIRC): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xe6f1beaf
666700665318955 | p2_lp2_l UPCALL: TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xe6f1beaf
666700665524391 | p2_l ACTION (OUTPUT): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xe6f1beaf
666701668001799 | p2_l ACTION (HASH): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xc7257de2
666701668027419 | p2_l ACTION (RECIRC): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xc7257de2
666701668032677 | p2_lp2_l UPCALL: TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xc7257de2
666701668287302 | p2_l ACTION (OUTPUT): TCP(49450 -> 2399 [seq=15039 seq_ack=0] [SYN]) hash 0xc7257de2
^C
Event count:
UPCALL: 6
ACTION: 12

Save events for offline visualization

ovs-dptrace -output samples.data
^C
Written 12 samples

Visualize previously saved samples:

ovs-dptrace -input samples.data
666886611499599 | p2_l ACTION (HASH): TCP(49454 -> 2399 [seq=52003 seq_ack=0] [SYN]) hash 0x9d1dab7e
...
Event count:
UPCALL: 3
ACTION: 9