[root@oldweb ~]# udevinfo -a -p /sys/class/net/eth0

udevinfo starts with the device the node belongs to and then walks up the
device chain, to print for every device found, all possibly useful attributes
in the udev key format.
Only attributes within one device section may be used together in one rule,
to match the device for which the node will be created.

  looking at class device '/sys/class/net/eth0':
    SYSFS{addr_len}="6"
    SYSFS{address}="00:c0:9f:16:d0:5a"
    SYSFS{broadcast}="ff:ff:ff:ff:ff:ff"
    SYSFS{features}="0x0"
    SYSFS{flags}="0x1003"
    SYSFS{ifindex}="2"
    SYSFS{iflink}="2"
    SYSFS{mtu}="1500"
    SYSFS{tx_queue_len}="1000"
    SYSFS{type}="1"

follow the class device's "device"
  looking at the device chain at '/sys/devices/pci0000:00/0000:00:07.0':
    BUS="pci"
    ID="0000:00:07.0"
    SYSFS{class}="0x020000"
    SYSFS{detach_state}="0"
    SYSFS{device}="0x1229"
    SYSFS{irq}="177"
    SYSFS{subsystem_device}="0x8917"
    SYSFS{subsystem_vendor}="0x152d"
    SYSFS{vendor}="0x8086"

  looking at the device chain at '/sys/devices/pci0000:00':
    BUS=""
    ID="pci0000:00"
    SYSFS{detach_state}="0"