[PATCH] net: dhcp: allow to set transmitted vendor id

[PATCH] net: dhcp: allow to set transmitted vendor id

[Enrico Scholz]

For net boot setups it is useful to submit boot params like server or
bootfile over dhcp.  To distinguish barebox from e.g. pxe machines, a
custom vendor id can be sent in dhcp discover/request messages.

E.g. the ISC dhcp server can be configured with

| if substring(option vendor-class-identifier,0,8) = "barebox:" {
| 	next-server		192.168.3.24;
| 	server-name		"192.168.3.24";
| 	option tftp-server-name	"192.168.3.24";
| 	option root-path = concat("/srv/sysroots/by-mac/",
|          binary-to-ascii (16, 8, "-", substring (hardware, 1, 6)));
| }

to sent boot params which are valid for barebox hosts only.

Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
---
 net/Kconfig |   13 +++++++++++++
 net/dhcp.c  |   12 ++++++++++++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/net/Kconfig b/net/Kconfig
index 3169d20..56d6ee8 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -7,6 +7,19 @@ config NET_DHCP
 	bool
 	prompt "dhcp support"
 
+config NET_DHCP_VENDOR_ID
+        string
+	prompt "dhcp vendor id"
+	depends on NET_DHCP
+	default "barebox:default"
+	help
+	  DHCP Vendor ID (code 60) submitted in DHCP requests. It can
+	  be used in the DHCP server's configuration to select options
+	  (e.g. bootfile or server) which are valid for barebox clients
+	  only.
+
+	  An empty string will suppress generation of such requests.
+
 config NET_NFS
 	bool
 	prompt "nfs support"
diff --git a/net/dhcp.c b/net/dhcp.c
index 2ce9090..65f2614 100644
--- a/net/dhcp.c
+++ b/net/dhcp.c
@@ -129,6 +129,7 @@ static void bootp_copy_net_params(struct bootp *bp)
  */
 static int dhcp_extended (u8 *e, int message_type, IPaddr_t ServerID, IPaddr_t RequestedIP)
 {
+	size_t vendor_id_len = sizeof CONFIG_NET_DHCP_VENDOR_ID - 1;
 	u8 *start = e;
 	u8 *cnt;
 
@@ -168,6 +169,17 @@ static int dhcp_extended (u8 *e, int message_type, IPaddr_t ServerID, IPaddr_t R
 		*e++ = tmp & 0xff;
 	}
 
+	/* 64 is some arbitrary value to prevent generation of too
+	 * large dhcp requests. */
+	BUILD_BUG_ON(sizeof CONFIG_NET_DHCP_VENDOR_ID > 64);
+
+	if (vendor_id_len > 0) {
+		*e++ = 60;
+		*e++ = vendor_id_len;
+		memcpy(e, CONFIG_NET_DHCP_VENDOR_ID,  vendor_id_len);
+		e   += vendor_id_len;
+	}
+
 	*e++ = 55;		/* Parameter Request List */
 	 cnt = e++;		/* Pointer to count of requested items */
 	*cnt = 0;
-- 
1.7.7.6


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Re: [PATCH] net: dhcp: allow to set transmitted vendor id

[Jean-Christophe PLAGNIOL-VILLARD]

On 18:36 Tue 06 Mar     , Enrico Scholz wrote:
> For net boot setups it is useful to submit boot params like server or
> bootfile over dhcp.  To distinguish barebox from e.g. pxe machines, a
> custom vendor id can be sent in dhcp discover/request messages.
> 
> E.g. the ISC dhcp server can be configured with
> 
> | if substring(option vendor-class-identifier,0,8) = "barebox:" {
> | 	next-server		192.168.3.24;
> | 	server-name		"192.168.3.24";
> | 	option tftp-server-name	"192.168.3.24";
> | 	option root-path = concat("/srv/sysroots/by-mac/",
> |          binary-to-ascii (16, 8, "-", substring (hardware, 1, 6)));
> | }
> 
> to sent boot params which are valid for barebox hosts only.
like the idea
but the vendor id is barebox and can be overwrite it for each eth device via
param

Best Regards,
J.

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Re: [PATCH] net: dhcp: allow to set transmitted vendor id

[Sascha Hauer]

On Tue, Mar 06, 2012 at 06:36:15PM +0100, Enrico Scholz wrote:
> For net boot setups it is useful to submit boot params like server or
> bootfile over dhcp.  To distinguish barebox from e.g. pxe machines, a
> custom vendor id can be sent in dhcp discover/request messages.
> 
> E.g. the ISC dhcp server can be configured with
> 
> | if substring(option vendor-class-identifier,0,8) = "barebox:" {
> | 	next-server		192.168.3.24;
> | 	server-name		"192.168.3.24";
> | 	option tftp-server-name	"192.168.3.24";
> | 	option root-path = concat("/srv/sysroots/by-mac/",
> |          binary-to-ascii (16, 8, "-", substring (hardware, 1, 6)));
> | }
> 
> to sent boot params which are valid for barebox hosts only.

I like this one aswell. The string shouldn't be hardcoded though.
It could be a command line option to dhcp.

Sascha

> 
> Signed-off-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
> ---
>  net/Kconfig |   13 +++++++++++++
>  net/dhcp.c  |   12 ++++++++++++
>  2 files changed, 25 insertions(+), 0 deletions(-)
> 
> diff --git a/net/Kconfig b/net/Kconfig
> index 3169d20..56d6ee8 100644
> --- a/net/Kconfig
> +++ b/net/Kconfig
> @@ -7,6 +7,19 @@ config NET_DHCP
>  	bool
>  	prompt "dhcp support"
>  
> +config NET_DHCP_VENDOR_ID
> +        string
> +	prompt "dhcp vendor id"
> +	depends on NET_DHCP
> +	default "barebox:default"
> +	help
> +	  DHCP Vendor ID (code 60) submitted in DHCP requests. It can
> +	  be used in the DHCP server's configuration to select options
> +	  (e.g. bootfile or server) which are valid for barebox clients
> +	  only.
> +
> +	  An empty string will suppress generation of such requests.
> +
>  config NET_NFS
>  	bool
>  	prompt "nfs support"
> diff --git a/net/dhcp.c b/net/dhcp.c
> index 2ce9090..65f2614 100644
> --- a/net/dhcp.c
> +++ b/net/dhcp.c
> @@ -129,6 +129,7 @@ static void bootp_copy_net_params(struct bootp *bp)
>   */
>  static int dhcp_extended (u8 *e, int message_type, IPaddr_t ServerID, IPaddr_t RequestedIP)
>  {
> +	size_t vendor_id_len = sizeof CONFIG_NET_DHCP_VENDOR_ID - 1;
>  	u8 *start = e;
>  	u8 *cnt;
>  
> @@ -168,6 +169,17 @@ static int dhcp_extended (u8 *e, int message_type, IPaddr_t ServerID, IPaddr_t R
>  		*e++ = tmp & 0xff;
>  	}
>  
> +	/* 64 is some arbitrary value to prevent generation of too
> +	 * large dhcp requests. */
> +	BUILD_BUG_ON(sizeof CONFIG_NET_DHCP_VENDOR_ID > 64);
> +
> +	if (vendor_id_len > 0) {
> +		*e++ = 60;
> +		*e++ = vendor_id_len;
> +		memcpy(e, CONFIG_NET_DHCP_VENDOR_ID,  vendor_id_len);
> +		e   += vendor_id_len;
> +	}
> +
>  	*e++ = 55;		/* Parameter Request List */
>  	 cnt = e++;		/* Pointer to count of requested items */
>  	*cnt = 0;
> -- 
> 1.7.7.6
> 
> 
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> 

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