[Linux] net_if_stats() returns an incorrect speed value for 100GbE network cards

[garrisoncarter]

Summary

• OS: Linux
• Bug fix: Yes
• Type: Core
• Fixes: [Ubuntu 20.04] net_if_stats() returns incorrect interface speed for 100GbE network cards #2095

Description

Properly handle the speed variable from ethtool.h to support interface speed that are greater than UINT16_MAX. Since ethtool returns the interface speed as two separate uint16_t values, in order to determine the actual interface speed, you must combine and bit-shift the two values.

Testing

All testing done on Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-100-generic x86_64) with Python 3.8.10.

System with 100GbE network interface up (eth2). Confirmed that interfaces that are down show a speed of 0, and the 100GbE interface that is up properly returns 100,000 Mb/s.

>>> import psutil
>>> psutil.net_if_stats()
{'eth1': snicstats(isup=False, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=1500), 'eth0': snicstats(isup=False, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=1500), 'eth2': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_FULL: 2>, speed=100000, mtu=1500), 'lo': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=65536)}
>>>

System with 10GbE network interface up (eth1)

>>> import psutil
>>> psutil.net_if_stats()
{'lo': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=65536), 'eth0': snicstats(isup=False, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=1500), 'eth1': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_FULL: 2>, speed=10000, mtu=1500)}
>>>