Hi Malice, On 06/25/2012 09:42 PM, Malice wrote:
Hi
I'm planning to write a new device driver on linux kernel . The device i intend to write will be a device that'll pipe the data coming into it to another computer that'll be also having the same device . So in short the device'll be readable/writable and should communicate through network . I know it sounds like a socket but the idea would be to implement a interface in shell so that if you type
| root@host$echo "Hi">>mydevice |
will transfer the word hi to the system on the other side of network (and may be configure it to store on file). This is a leisure time project i intend to do and it sounds much like sockets and other already existing implementations . Well the questions regarding the design for device implementations are : 1)Should i use a block or a character device . The advantage i see for a block device is that if i am a initiating a complete file transfer through the device(which i in tend to support later) , then it would be fast .
2)How do i write the data on the network . I'm familiar with sockets and stuff , but using sockets from with in the kernel has performance issues(I read it somewhere, after all sockets was desined to be used in userspace) . Will using netfilter or other stuffs work ?Maybe crafting the packet directly would help :-)? Any innovations are welcome
have a look on the tun/tap driver, I think that's what you need. http://lxr.free-electrons.com/source/drivers/net/tun.c
3)How do i configure the driver , like how do i let it know that it should connect to a specific host >in user space programs we usually do this by config files , but to change the connection settings of a driver how do you manage it ? (sysfs ?? Frankly i never worked with sysfs or proc/ )
4)Now as the design specifies all the transfer of files is in kernel space . When i transfer huge chunks of data through kernel space , will it slow down the system ?. The design shouldnt overload the system , doing it in a pre-empitble kernel will help, but are there other charecterstics i should be aware of to make the design as efficient as possible (i'm doing it on the latest linux kernel) ?
5)And i dont want to leave a huge memory imprint so is there any way i can reduce it while tranferring of data , may be cacheing data on disk ?
6)I will have to design a user space programme to co ordinate the driver wont i ? I cannot let the driver alone do the whole task , tat wud be tedious
Comments Welcome
I've also posted the same question at stackoverflow too http://stackoverflow.com/questions/11167424/writing-a-new-device-driver
Regards Malice
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