*Sender side
↓非root権限なのでioctlできない
syuu@monster:~/UDP-Pinger$ ./udp_sender 192.168.100.252 10000 3 eno1
ioctl(SIOCSHWTSTAMP): Operation not permitted
Enabling SW TX timestamp
Ping packet send to 192.168.100.252 port 10000
    SND: 1493282680 s 317072 us (seq=0, len=0)

Pong Message Received
RTT: 0.450 Seconds
Ping packet send to 192.168.100.252 port 10000
    SND: 1493282680 s 317546 us (seq=1, len=0)  (+474 us)

Pong Message Received
RTT: 0.352 Seconds
Ping packet send to 192.168.100.252 port 10000
    SND: 1493282680 s 317912 us (seq=2, len=0)  (+366 us)

Pong Message Received
RTT: 0.291 Seconds

syuu@monster:~/UDP-Pinger$ sudo ./udp_sender 192.168.100.252 10000 3 eno1
↓e1000eは多分非対応だと思うけどエラー返さずに黙って吸い込んだ結果、タイムスタンプが何も返ってこない（ドライバのバグ）
Enabling HW TX timestamp
Ping packet send to 192.168.100.252 port 10000

Pong Message Received
RTT: 0.373 Seconds
Ping packet send to 192.168.100.252 port 10000

Pong Message Received
RTT: 0.315 Seconds
Ping packet send to 192.168.100.252 port 10000

Pong Message Received
RTT: 0.358 Seconds

*Receiver side
↓非root権限なのでioctlできない
[syuu@devil UDP-Pinger]$  ./udp_receiver 10000 eno1
ioctl(SIOCSHWTSTAMP): Operation not permitted
Enabling SW RX timestamp

Listening on port 10000 ...

Ping Message Received
1493282828.974853: received regular data, 6 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282828.974729913 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...

Ping Message Received
1493282828.975244: received regular data, 4 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282828.975155295 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...

Ping Message Received
1493282828.975582: received regular data, 4 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282828.975508846 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...
↓こっちのドライバは新しいせいかちゃんとエラーを返してきているためSWタイムスタンプにフォールバックできてる
[syuu@devil UDP-Pinger]$ sudo  ./udp_receiver 10000 eno1
ioctl(SIOCSHWTSTAMP): No such device
Enabling SW RX timestamp

Listening on port 10000 ...

Ping Message Received
1493282892.287597: received regular data, 6 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282892.287490232 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...

Ping Message Received
1493282892.287902: received regular data, 4 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282892.287865592 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...

Ping Message Received
1493282892.288147: received regular data, 4 bytes from 192.168.100.253, 64 bytes control messages
   cmsg len 64: SOL_SOCKET SO_TIMESTAMPING SW 1493282892.288121322 HW raw 0.000000000

Pong Message Send

---------------

Listening on port 10000 ...