Implementing ping(8) in Go

Presentation for Go Northwest 2018 https://gonorthwest.io/

Source code is available at https://github.com/erriapo/goping

Transcript

1. Implementing ping(8) in Go Gavin Chun Jin Go Northwest 2018
2. Features of Simple clone of ping(8) with minimal features. goping • IPv4 only. • Option to control the number of ECHO_REQUEST E.g. ping -c 4 www.google.ca • No support for -s packetsize ICMP payload is a constant.
3. Sample ping(8) output
4. Sample output goping
5. ICMP packet IPv4 Echo Request (Type 8, Code 0) IPv4 Echo Reply (Type 0, Code 0)
6. ICMP packet
7. Rendering output 1 goping
8. Rendering output 2 goping https://github.com/erriapo/stats To maintain a running variance of RTTs as they come in, we use B. P. Welford’s method (1962). Formula is taken with permission from John D Cook’s blogpost.
9. Raw sockets Only processes with an effective user ID of 0 or the CAP_NET_RAW attribute may do that. ~ man 7 raw You can run goping SETUID root or give the binary the minimum linux capability to use raw sockets.
10. Raw sockets ping(8) is setuid root! .
11. Interlude
12. goping In a multi nic situation, you can direct goping to send the ICMP probes via a specific interface. supports multiple interfaces 1
13. goping . supports multiple interfaces 2
14. goping golang.org/x/net/idna & punycode domains
15. Weird behaviour 1
16. Weird behaviour 1
17. Weird behaviour 2
18. Weird behaviour 2
19. Thank you @GavinGastown3 https://github.com/erriapo/goping