[lwip-users] Re: [lwip] /dev/tap0

[Felipe Massia Pereira]

Amol Deshmukh wrote:
> I tried compiling lwip-0.4.1 on Red Hat Linux 7.1 (kernel
> 2.4.2). It compiled after adding
> #define PBUF_MAX_SIZE 1500 to the file /src/include/lwip/pbuf.h
>      I installed the vtun interface driver before running the code.
> 
>  Running ./simhost as root gives the following output.
> 
>  System initialized.
> tapif_init: No such file or directory
> 
> It does not find the file "/dev/tap0" in the function tapif_init in file
> src/arch/unix/netif/tapif.c.
> I do not understand much about taptunnel or vtun interface driver.
> Though I am a newbie, could you please help me in this matter. Thanks in
> advance.

I use RedHat 7.1 too. The /dev/tap0 file is not created in the default
installation, then you must do as root

address@hidden:/dev/ # ./MAKEDEV tap

The tap should be enabled as a module. When the device is opened, the kernel
creates an interface.

About the kernel version... If I'm not mistaken, there were two devices,
before: /dev/tun and /dev/tap. Now there is only tap, but you can configure
it as tun or tap with an ioctl call. If you are interested in programming,
take a look at the site

http://vtun.sourceforge.net/tun/

which is the official development site for the driver. It should be enabled
as a kernel module by default, so there is no need for recompilation, unless
you want to enable driver debug options or such.

I tried to run lwip 0.0.3 under Linux RedHat 7 (2.4 kernel too, I think),
and it was unsuccessful. I even tried to adapt it to the new tap driver
using the code sample provided in the tun/tap site, but even when I got it
working (i.e. opening the device, configuring the IP address of the tap
interface) lwip didnt work. I dont know if the new version works ok with
Linux. I will be trying soon. I thought that the Linux side was in
development (there was a lot of lines commented out).

And how did I run lwip? Well, I installed a FreeBSD :-)))

[]s
Felipe
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