[SOLVED] [udev] Specific network is I want to know whether or wired is wireless.

TeaYoung · 11-10-2014, 05:00 AM

Hello.

I is specific network interface you want to know whether or wired is wireless.

For example, eth0 is I want to know whether or wired is wireless.

I I'd want to do this to udev. So I saw the eth0 and eth1 to udevadm.

Quote:

root@test:~# udevadm info -a -p /sys/class/net/eth0

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

looking at device '/devices/virtual/net/eth0':
KERNEL=="eth0"
SUBSYSTEM=="net"
DRIVER==""
ATTR{mtu}=="1500"
ATTR{type}=="1"
ATTR{netdev_group}=="0"
ATTR{flags}=="0x1003"
ATTR{dormant}=="0"
ATTR{addr_assign_type}=="0"
ATTR{dev_id}=="0x0"
ATTR{iflink}=="2"
ATTR{addr_len}=="6"
ATTR{address}=="00:15:1d:00:00:00"
ATTR{operstate}=="up"
ATTR{broadcast}=="ff:ff:ff:ff:ff:ff"
ATTR{tx_queue_len}=="1000"
ATTR{ifalias}==""
ATTR{ifindex}=="2"
ATTR{link_mode}=="0"
ATTR{carrier}=="1"

root@test:~#

Quote:

root@test:~# udevadm info -a -p /sys/class/net/eth1

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

looking at device '/devices/platform/exynos4-sdhci.3/mmc_host/mmc1/mmc1:0001/mmc1:0001:1/net/eth1':
KERNEL=="eth1"
SUBSYSTEM=="net"
DRIVER==""
ATTR{mtu}=="1500"
ATTR{type}=="1"
ATTR{netdev_group}=="0"
ATTR{flags}=="0x1002"
ATTR{addr_assign_type}=="0"
ATTR{dev_id}=="0x0"
ATTR{iflink}=="3"
ATTR{addr_len}=="6"
ATTR{address}=="c4:23:7a:00:6e:93"
ATTR{operstate}=="down"
ATTR{broadcast}=="ff:ff:ff:ff:ff:ff"
ATTR{tx_queue_len}=="1000"
ATTR{ifalias}==""
ATTR{ifindex}=="3"
ATTR{link_mode}=="0"

looking at parent device '/devices/platform/exynos4-sdhci.3/mmc_host/mmc1/mmc1:0001/mmc1:0001:1':
KERNELS=="mmc1:0001:1"
SUBSYSTEMS=="sdio"
DRIVERS=="unifi"
ATTRS{class}=="0x00"
ATTRS{device}=="0x0007"
ATTRS{vendor}=="0x032a"

looking at parent device '/devices/platform/exynos4-sdhci.3/mmc_host/mmc1/mmc1:0001':
KERNELS=="mmc1:0001"
SUBSYSTEMS=="mmc"
DRIVERS==""
ATTRS{type}=="SDIO"

looking at parent device '/devices/platform/exynos4-sdhci.3/mmc_host/mmc1':
KERNELS=="mmc1"
SUBSYSTEMS=="mmc_host"
DRIVERS==""

looking at parent device '/devices/platform/exynos4-sdhci.3':
KERNELS=="exynos4-sdhci.3"
SUBSYSTEMS=="platform"
DRIVERS=="s3c-sdhci"

looking at parent device '/devices/platform':
KERNELS=="platform"
SUBSYSTEMS==""
DRIVERS==""

root@test:~#

In my opinion, I think that it can be determined to have the ATTR {flags}.

ATTR {flags} is in the wireless if 0x1002, if it is 0x1003, you have a guess and wired.

My thinking is that correct?

Is the information for the flags can be found where?

how corresponding interface without knowing to have you need to determine whether a wireless or a wired the flags?

neonsignal · 12-09-2014, 07:43 AM

No, the difference between the flags here only tell you that one of your interfaces is up and the other is down.

You will find documentation for the net subsystem at kernel.org. And documentation specifically for the net flags in the source.

You can tell which interface is which by getting the hardware address using ipconfig or

Code:

ip a

And determine the matching hardware using

Code:

lshw -class network

From the udev perspective, many drivers assign wireless interfaces to names like "wlan0" rather than "eth0", so that other rules can then wildcard match on the name "wlan*". But this is not consistent between drivers. You can manually override these on a particular system by editing the "NAME" parameters in "/usr/dev/rules.d/70-persistent-net-rules".