Re: [PATCH rfc net] Allow the autoconfigured network interface to be renamed.

[Scott Parlane <scott@scottnz.com>]

Hi David,

Can you please deliver this patch (my apologies if you have already).

We have been running it for several months on ~80 x86 machines
(against 3.3.0-gentoo)
and have had no issues related to it.
It applied cleanly to tovalds.git and net.git when I created it.

Please let me know if it requires any changes,
I believe I complied with the coding style present in the file.

Kind Regards,
Scott

On Sat, 2012-06-09 at 19:48 +1200, Scott Parlane wrote:
> From: Scott Parlane <scott.parlane@alliedtelesis.co.nz>
> 
> if IP_PNP_RENAME_DEV is set, the first interface to be configured
> automatically by the kernel during boot will be renamed.
> 
> IP_PNP_DEV_NEWNAME is the name to give the autoconfigured device.
> 
> No changes will be made to any interface that is not autoconfigured.
> 
> This allows the assurance of the boot device name, without the need
> for an initramfs.
> 
> Signed-off-by: Scott Parlane <scott.parlane@alliedtelesis.co.nz>
> ---
>  net/ipv4/Kconfig    |   17 +++++++++++++++++
>  net/ipv4/ipconfig.c |   35 +++++++++++++++++++++++++++++++++++
>  2 files changed, 52 insertions(+), 0 deletions(-)
> 
> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
> index 20f1cb5..c85c654 100644
> --- a/net/ipv4/Kconfig
> +++ b/net/ipv4/Kconfig
> @@ -163,6 +163,23 @@ config IP_PNP_RARP
>  	  operating on your network. Read
>  	  <file:Documentation/filesystems/nfs/nfsroot.txt> for details.
>  
> +config IP_PNP_RENAME_DEV
> +	bool "IP: Rename boot device"
> +	depends on IP_PNP
> +	help
> +	 If you want to rename the network device you are booting from
> +	 to something other than eth%d enable this option, and choose the name
> +	 below. This is helpful if you want to use udev to keep
> +	 persistent naming of your other interfaces.
> +
> +config IP_PNP_DEV_NEWNAME
> +	string "IP: New name of boot device"
> +	depends on IP_PNP_RENAME_DEV
> +	default "bootnet"
> +	help
> +	 The name to assign to the network device you are booting from
> +	 when using ip autoconfigure
> +
>  config NET_IPIP
>  	tristate "IP: tunneling"
>  	select INET_TUNNEL
> diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
> index 67e8a6b..a4b052a 100644
> --- a/net/ipv4/ipconfig.c
> +++ b/net/ipv4/ipconfig.c
> @@ -86,6 +86,10 @@
>  #if defined(IPCONFIG_BOOTP) || defined(IPCONFIG_RARP)
>  #define IPCONFIG_DYNAMIC
>  #endif
> +#if defined(CONFIG_IP_PNP_RENAME_DEV)
> +#define IPCONFIG_RENAME_DEV
> +#define IPCONFIG_DEV_NEWNAME CONFIG_IP_PNP_DEV_NEWNAME
> +#endif
>  
>  /* Define the friendly delay before and after opening net devices */
>  #define CONF_POST_OPEN		10	/* After opening: 10 msecs */
> @@ -360,6 +364,37 @@ static int __init ic_setup_if(void)
>  
>  	memset(&ir, 0, sizeof(ir));
>  	strcpy(ir.ifr_ifrn.ifrn_name, ic_dev->name);
> +#ifdef IPCONFIG_RENAME_DEV
> +	if ((err = ic_dev_ioctl(SIOCGIFFLAGS, &ir)) < 0) {
> +		pr_err("IP-Config: Unable to get interface flags (1,%d).\n",
> +		       err);
> +		return -1;
> +	}
> +	ir.ifr_flags &= ~IFF_UP;
> +	if ((err = ic_dev_ioctl(SIOCSIFFLAGS, &ir)) < 0) {
> +		pr_err("IP-Config: Unable to set interface flags (1,%d).\n",
> +		       err);
> +		return -1;
> +	}
> +	strcpy(ir.ifr_newname, IPCONFIG_DEV_NEWNAME);
> +	if ((err = ic_dev_ioctl(SIOCSIFNAME, &ir)) < 0) {
> +		pr_err("IP-Config: Unable to change boot interface name to %s (%d).\n",
> +		       IPCONFIG_DEV_NEWNAME, err);
> +		return -1;
> +	}
> +	strcpy(ir.ifr_ifrn.ifrn_name, IPCONFIG_DEV_NEWNAME);
> +	if ((err = ic_dev_ioctl(SIOCGIFFLAGS, &ir)) < 0) {
> +		pr_err("IP-Config: Unable to get interface flags (2,%d).\n",
> +		       err);
> +		return -1;
> +	}
> +	ir.ifr_flags |= IFF_UP;
> +	if ((err = ic_dev_ioctl(SIOCSIFFLAGS, &ir)) < 0) {
> +		pr_err("IP-Config: Unable to set interface flags (2,%d).\n",
> +		       err);
> +		return -1;
> +	}
> +#endif
>  	set_sockaddr(sin, ic_myaddr, 0);
>  	if ((err = ic_devinet_ioctl(SIOCSIFADDR, &ir)) < 0) {
>  		pr_err("IP-Config: Unable to set interface address (%d)\n",