RE: [RFC PATCH net-next v2 1/1] net: Support for switch port configuration

Varlese, Marco
2014-12-18T15:22:37Z

> -----Original Message-----
> From: Thomas Graf [mailto:tgr@infradead.org] On Behalf Of Thomas Graf
> Sent: Thursday, December 18, 2014 11:42 AM
> To: Varlese, Marco
> Cc: netdev@vger.kernel.org; Fastabend, John R; Jiri Pirko;
> roopa@cumulusnetworks.com; sfeldma@gmail.com; linux-
> kernel@vger.kernel.org
> Subject: Re: [RFC PATCH net-next v2 1/1] net: Support for switch port
> configuration
>
> On 12/18/14 at 11:29am, Varlese, Marco wrote:
> > diff --git a/include/uapi/linux/if_link.h
> > b/include/uapi/linux/if_link.h index f7d0d2d..19cb51a 100644
> > --- a/include/uapi/linux/if_link.h
> > +++ b/include/uapi/linux/if_link.h
> > @@ -146,6 +146,7 @@ enum {
> > IFLA_PHYS_PORT_ID,
> > IFLA_CARRIER_CHANGES,
> > IFLA_PHYS_SWITCH_ID,
> > + IFLA_SWITCH_PORT_CFG,
> > __IFLA_MAX
> > };
>
> Needs an entry in ifla_policy[]
>
> [IFLA_SWITCH_PORT_CFG] = { .type = NLA_NESTED },
>
> > @@ -603,4 +604,18 @@ enum {
> >
> > #define IFLA_HSR_MAX (__IFLA_HSR_MAX - 1)
> >
> > +/* Switch Port Attributes section */
> > +
> > +enum {
> > + IFLA_ATTR_UNSPEC,
> > + IFLA_ATTR_LEARNING,
> > + IFLA_ATTR_LOOPBACK,
> > + IFLA_ATTR_BCAST_FLOODING,
> > + IFLA_ATTR_UCAST_FLOODING,
> > + IFLA_ATTR_MCAST_FLOODING,
> > + __IFLA_ATTR_MAX
> > +};
> > +
> > +#define IFLA_ATTR_MAX (__IFLA_ATTR_MAX - 1)
>
> Change the prefix to IFLA_SW_* since it's switch specific?
>
> >
> > +#ifdef CONFIG_NET_SWITCHDEV
> > +static int do_setswcfg(struct net_device *dev, struct nlattr *attr) {
> > + int rem, err = -EINVAL;
> > + struct nlattr *v;
> > + const struct net_device_ops *ops = dev->netdev_ops;
> > +
> > + nla_for_each_nested(v, attr, rem) {
> > + u32 op = nla_type(v);
> > + u64 value = 0;
> > +
> > + switch (op) {
> > + case IFLA_ATTR_LEARNING:
> > + case IFLA_ATTR_LOOPBACK:
> > + case IFLA_ATTR_BCAST_FLOODING:
> > + case IFLA_ATTR_UCAST_FLOODING:
> > + case IFLA_ATTR_MCAST_FLOODING: {
> > + if (nla_len(v) < sizeof(value)) {
> > + err = -EINVAL;
> > + break;
> > + }
>
> You should validate the message before you start applying the changes.
> Otherwise if the 3rd attribute is too short you've already applied some
> changes and the user has not idea how much has been applied.
>
> nla_parse_nested() can help here.
>
>
> > +
> > + value = nla_get_u64(v);
> > + err = ops->ndo_switch_port_set_cfg(dev,
> > + op,
> > + value);
>
> This avoids having individual ndos but wastes a lot of space in the Netlink
> message. Not a problem when setting configuration but you likely want to
> dump these attributes as well and we need 12 bytes for each attribute even
> though some are merely flags which could fit in 4 bytes.
>
> > static int do_setvfinfo(struct net_device *dev, struct nlattr *attr)
> > {
> > int rem, err = -EINVAL;
> > @@ -1740,6 +1780,20 @@ static int do_setlink(const struct sk_buff *skb,
> > status |= DO_SETLINK_NOTIFY;
> > }
> > }
> > +#ifdef CONFIG_NET_SWITCHDEV
> > + if (tb[IFLA_SWITCH_PORT_CFG]) {
> > + err = -EOPNOTSUPP;
> > + if (!ops->ndo_switch_port_set_cfg)
> > + goto errout;
> > + if (!ops->ndo_switch_parent_id_get)
> > + goto errout;
> > + err = do_setswcfg(dev, tb[IFLA_SWITCH_PORT_CFG]);
> > + if (err < 0)
> > + goto errout;
> > +
> > + status |= DO_SETLINK_NOTIFY;
> > + }
> > +#endif
>
> Should return -EOPNOTSUPP if IFLA_SWITCH_PORT_CFG is provided but
> CONFIG_NET_SWITCHDEV is not set.
>

I think I've addressed your comments Thomas. Thanks for your suggestions. I'm going to resubmit the patch now.

Thanks,
Marco