Usbnet

usbnet is the Ethernet over USB Network driver shim in the Linux kernel.

The source for the USB Network layer can be found in the Linux kernel at drivers/net/usb

The source for usbnet.c, in particular, is at: drivers/net/usb/usbnet.c

Interesting drivers within the USB Networking layer are:

• drivers/net/usb/asix.c
• drivers/net/usb/cdc_ether.c

Internals

usbnet.c provides the usbnet_get_endpoints() function which searches the alternate endpoints from the attached USB device looking for a Bulk In and a Bulk Out endpoint as well as an optional Interrupt In endpoint (for status).

Gadget drivers

Linux kernel seems to prefer the term "gadget" when referring to USB Device support for devices running Linux.

Support in the Linux kernel for Ethernet over USB networking from the devices end, if the device CPU is running Linux:

• drivers/usb/gadget/ether.c
• drivers/usb/gadget/u_ether.c

External Links

• The GNU/Linux "usbnet" Driver
• Ethernet over USB at Wikipedia