Subject: Re: [patch net-next v2 03/10] rtnl: expose physical switch id for particular device

From: Roopa Prabhu <[email-masked]>
Date: Mon, 10 Nov 2014 09:58:08 -0800

On 11/9/14, 2:51 AM, Jiri Pirko wrote:
> The netdevice represents a port in a switch, it will expose
> IFLA_PHYS_SWITCH_ID value via rtnl. Two netdevices with the same value
> belong to one physical switch.
>
> Signed-off-by: Jiri Pirko <[email-masked]>
> ---
>   include/uapi/linux/if_link.h |  1 +
>   net/core/rtnetlink.c         | 26 +++++++++++++++++++++++++-
>   2 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
> index 7072d83..4163753 100644
> --- a/include/uapi/linux/if_link.h
> +++ b/include/uapi/linux/if_link.h
> @@ -145,6 +145,7 @@ enum {
>   	IFLA_CARRIER,
>   	IFLA_PHYS_PORT_ID,
>   	IFLA_CARRIER_CHANGES,
> +	IFLA_PHYS_SWITCH_ID,

Jiri, since we have not really converged on the switchdev class or 
having a separate switchdev instance,
am thinking it is better if we dont expose any such switch_id to 
userspace yet until absolutely needed. Do you need it today ?
There is no real in kernel hw switch driver that will use it today. And 
quite likely this will need to change when we introduce real hw switch 
drivers.

>   	__IFLA_MAX
>   };
>   
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 1087c6d..f839354 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -43,6 +43,7 @@
>   
>   #include <linux/inet.h>
>   #include <linux/netdevice.h>
> +#include <net/switchdev.h>
>   #include <net/ip.h>
>   #include <net/protocol.h>
>   #include <net/arp.h>
> @@ -868,7 +869,8 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
>   	       + rtnl_port_size(dev, ext_filter_mask) /* IFLA_VF_PORTS + IFLA_PORT_SELF */
>   	       + rtnl_link_get_size(dev) /* IFLA_LINKINFO */
>   	       + rtnl_link_get_af_size(dev) /* IFLA_AF_SPEC */
> -	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN); /* IFLA_PHYS_PORT_ID */
> +	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_PORT_ID */
> +	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN); /* IFLA_PHYS_SWITCH_ID */
>   }
>   
>   static int rtnl_vf_ports_fill(struct sk_buff *skb, struct net_device *dev)
> @@ -967,6 +969,24 @@ static int rtnl_phys_port_id_fill(struct sk_buff *skb, struct net_device *dev)
>   	return 0;
>   }
>   
> +static int rtnl_phys_switch_id_fill(struct sk_buff *skb, struct net_device *dev)
> +{
> +	int err;
> +	struct netdev_phys_item_id psid;
> +
> +	err = netdev_sw_parent_id_get(dev, &psid);
> +	if (err) {
> +		if (err == -EOPNOTSUPP)
> +			return 0;
> +		return err;
> +	}
> +
> +	if (nla_put(skb, IFLA_PHYS_SWITCH_ID, psid.id_len, psid.id))
> +		return -EMSGSIZE;
> +
> +	return 0;
> +}
> +
>   static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
>   			    int type, u32 pid, u32 seq, u32 change,
>   			    unsigned int flags, u32 ext_filter_mask)
> @@ -1039,6 +1059,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
>   	if (rtnl_phys_port_id_fill(skb, dev))
>   		goto nla_put_failure;
>   
> +	if (rtnl_phys_switch_id_fill(skb, dev))
> +		goto nla_put_failure;
> +
>   	attr = nla_reserve(skb, IFLA_STATS,
>   			sizeof(struct rtnl_link_stats));
>   	if (attr == NULL)
> @@ -1198,6 +1221,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
>   	[IFLA_NUM_RX_QUEUES]	= { .type = NLA_U32 },
>   	[IFLA_PHYS_PORT_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
>   	[IFLA_CARRIER_CHANGES]	= { .type = NLA_U32 },  /* ignored */
> +	[IFLA_PHYS_SWITCH_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
>   };
>   
>   static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {