ping

Example imcp protocol implemented by raw socket in golang using unix package. For learning purpose, it only captures popular icmp message type such as echo reply, destination unreachable.

example

Testing in container with following network interface

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.17.0.2  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:ac:11:00:02  txqueuelen 0  (Ethernet)
        RX packets 823  bytes 355599 (355.5 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 684  bytes 57966 (57.9 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 1950  bytes 112766 (112.7 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1950  bytes 112766 (112.7 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

veth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 20.1.0.10  netmask 255.255.255.0  broadcast 0.0.0.0
        ether 3e:e3:1e:81:64:c9  txqueuelen 1000  (Ethernet)
        RX packets 78  bytes 3276 (3.2 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 703  bytes 51176 (51.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

veth2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 20.1.0.11  netmask 255.255.255.0  broadcast 0.0.0.0
        ether 2e:1f:92:cb:90:99  txqueuelen 1000  (Ethernet)
        RX packets 703  bytes 51176 (51.1 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 78  bytes 3276 (3.2 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

1. Ping to ip address 20.1.0.11 via veth veth1

go run main.go 5 20.1.0.11 veth1

ping to: 20.1.0.11, response: ping reply, seq: 1, latency:0.000414
ping to: 20.1.0.11, response: ping reply, seq: 2, latency:0.000079
ping to: 20.1.0.11, response: ping reply, seq: 3, latency:0.000072
ping to: 20.1.0.11, response: ping reply, seq: 4, latency:0.000069
ping to: 20.1.0.11, response: ping reply, seq: 5, latency:0.000057

2. Ping to ip address 20.1.0.12 (unknown address) via veth1

go run main.go 5 20.1.0.12 veth1

ping to: 20.1.0.12, response: destination unreachable, seq: 1, latency:3.102430
ping to: 20.1.0.12, response: destination unreachable, seq: 2, latency:3.102498
ping to: 20.1.0.12, response: destination unreachable, seq: 3, latency:3.102499
ping to: 20.1.0.12, response: destination unreachable, seq: 4, latency:3.102500
ping to: 20.1.0.12, response: destination unreachable, seq: 5, latency:3.102498