Udev - 未捕获网络电缆热插拔事件

Question

此 udev 规则和脚本捕获网络接口更改：

/etc/udev/rules.d/90-netifchanges.rules:

# Call custom script when ethernet device(s) are changed/added/removed/etc in system
SUBSYSTEM=="net" \
, RUN+="/usr/bin/systemd-cat /usr/local/bin/netifchanges.sh '$env{ACTION}' '$name' '$id' '$sys$devpath'"

/usr/local/bin/netifchanges.sh记录到 systemd 日志的脚本：

#!/bin/bash -e
    
action=$1
ifname=$2
id=$3
syspath=$4
    
echo "Network interface $ifname ($id) $action"
printenv

可以在不重新启动的情况下进行测试：

udevadm control --reload-rules && udevadm -d trigger -v --type devices --subsystem-match net

然后查看日志journalctl -xe。

如果您没有使用 systemd 运行：

删除/usr/bin/systemd-cat替换为或或RUN+=".." echologger "..."echo "stuff" > /dev/kmsg您的发行版使用的其他方法

此外，您可以通过添加虚拟接口来查看日志事件：

# ip link add dummy0 type dummy
# ip link set dummy0 up
# ip link set dummy0 down
# ip link delete dummy0

您还可以找到很多有关接口的信息，udevadm例如：

# udevadm info -a /sys/class/net/eno1

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/pci0000:00/0000:00:19.0/net/eno1':
    KERNEL=="eno1"
    SUBSYSTEM=="net"
    DRIVER==""
    ATTR{gro_flush_timeout}=="0"
    ATTR{proto_down}=="0"
    ATTR{addr_assign_type}=="0"
    ATTR{flags}=="0x1103"
    ATTR{netdev_group}=="0"
    ATTR{name_assign_type}=="4"
    ATTR{broadcast}=="ff:ff:ff:ff:ff:ff"
    ATTR{operstate}=="up"
    ATTR{link_mode}=="0"
    ATTR{dev_port}=="0"
    ATTR{address}=="74:d0:2b:2c:6e:d7"
    ATTR{duplex}=="full"
    ATTR{carrier_changes}=="4"
    ATTR{type}=="1"
    ATTR{addr_len}=="6"
    ATTR{dev_id}=="0x0"
    ATTR{iflink}=="3"
    ATTR{mtu}=="1500"
    ATTR{speed}=="1000"
    ATTR{carrier_down_count}=="2"
    ATTR{ifalias}==""
    ATTR{carrier_up_count}=="2"
    ATTR{ifindex}=="3"
    ATTR{carrier}=="1"
    ATTR{tx_queue_len}=="1000"
    ATTR{dormant}=="0"

  looking at parent device '/devices/pci0000:00/0000:00:19.0':
    KERNELS=="0000:00:19.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="e1000e"
    ATTRS{device}=="0x1503"
    ATTRS{label}==" Onboard LAN"
    ATTRS{enable}=="1"
    ATTRS{irq}=="56"
    ATTRS{subsystem_vendor}=="0x1043"
    ATTRS{devspec}==""
    ATTRS{revision}=="0x06"
    ATTRS{subsystem_device}=="0x849c"
    ATTRS{local_cpus}=="ff"
    ATTRS{local_cpulist}=="0-7"
    ATTRS{class}=="0x020000"
    ATTRS{driver_override}=="(null)"
    ATTRS{broken_parity_status}=="0"
    ATTRS{msi_bus}=="1"
    ATTRS{vendor}=="0x8086"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{ari_enabled}=="0"
    ATTRS{index}=="1"
    ATTRS{numa_node}=="-1"
    ATTRS{d3cold_allowed}=="1"
    ATTRS{dma_mask_bits}=="64"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

这些链接到 sys 文件：

# cat /sys/class/net/eno1/operstate 
up

udevadm monitor还可以使用：

# udevadm -d monitor -p -k -u --subsystem-match=net
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[99386.755966] add      /devices/virtual/net/dummy0 (net)
ACTION=add
DEVPATH=/devices/virtual/net/dummy0
SUBSYSTEM=net
INTERFACE=dummy0
IFINDEX=12
SEQNUM=6842

rx-0: sd-device-monitor: Received device does not pass filter, ignoring
tx-0: sd-device-monitor: Received device does not pass filter, ignoring
UDEV  [99386.773912] add      /devices/virtual/net/dummy0 (net)
ACTION=add
DEVPATH=/devices/virtual/net/dummy0
SUBSYSTEM=net
INTERFACE=dummy0
IFINDEX=12
SEQNUM=6842
USEC_INITIALIZED=99386759873
ID_NET_NAMING_SCHEME=v240
ID_MM_CANDIDATE=1
ID_NET_DRIVER=dummy
ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
SYSTEMD_ALIAS=/sys/subsystem/net/devices/dummy0
TAGS=:systemd:

rx-0: sd-device-monitor: Received device does not pass filter, ignoring
tx-0: sd-device-monitor: Received device does not pass filter, ignoring
KERNEL[99392.704357] remove   /devices/virtual/net/dummy0 (net)
ACTION=remove
DEVPATH=/devices/virtual/net/dummy0
SUBSYSTEM=net
INTERFACE=dummy0
IFINDEX=12
SEQNUM=6847

UDEV  [99392.715832] remove   /devices/virtual/net/dummy0 (net)
ACTION=remove
DEVPATH=/devices/virtual/net/dummy0
SUBSYSTEM=net
INTERFACE=dummy0
IFINDEX=12
SEQNUM=6847
USEC_INITIALIZED=99386759873
ID_NET_NAMING_SCHEME=v240
ID_MM_CANDIDATE=1
ID_NET_DRIVER=dummy
ID_NET_LINK_FILE=/usr/lib/systemd/network/99-default.link
SYSTEMD_ALIAS=/sys/subsystem/net/devices/dummy0
TAGS=:systemd:

Answer 1