dcbnl: add support for retrieving peer configuration - ieee

These 2 patches add the support for retrieving the remote or peer DCBX
configuration via dcbnl for embedded DCBX stacks. The peer configuration
is part of the DCBX MIB and is useful for debugging and diagnostics of
the overall DCB configuration. The first patch add this support for IEEE
802.1Qaz standard the second patch add the same support for the older
CEE standard. Diff for v2 - the peer-app-info is CEE specific.
Signed-off-by: Shmulik Ravid <shmulikr@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/dcbnl.h

@@ -110,6 +110,20 @@ struct dcb_app {
 	__u16	protocol;
 };
 
+/**
+ * struct dcb_peer_app_info - APP feature information sent by the peer
+ *
+ * @willing: willing bit in the peer APP tlv
+ * @error: error bit in the peer APP tlv
+ *
+ * In addition to this information the full peer APP tlv also contains
+ * a table of 'app_count' APP objects defined above.
+ */
+struct dcb_peer_app_info {
+	__u8	willing;
+	__u8	error;
+};
+
 struct dcbmsg {
 	__u8               dcb_family;
 	__u8               cmd;
@@ -235,11 +249,25 @@ enum dcbnl_attrs {
 	DCB_ATTR_MAX = __DCB_ATTR_ENUM_MAX - 1,
 };
 
+/**
+ * enum ieee_attrs - IEEE 802.1Qaz get/set attributes
+ *
+ * @DCB_ATTR_IEEE_UNSPEC: unspecified
+ * @DCB_ATTR_IEEE_ETS: negotiated ETS configuration
+ * @DCB_ATTR_IEEE_PFC: negotiated PFC configuration
+ * @DCB_ATTR_IEEE_APP_TABLE: negotiated APP configuration
+ * @DCB_ATTR_IEEE_PEER_ETS: peer ETS configuration - get only
+ * @DCB_ATTR_IEEE_PEER_PFC: peer PFC configuration - get only
+ * @DCB_ATTR_IEEE_PEER_APP: peer APP tlv - get only
+ */
 enum ieee_attrs {
 	DCB_ATTR_IEEE_UNSPEC,
 	DCB_ATTR_IEEE_ETS,
 	DCB_ATTR_IEEE_PFC,
 	DCB_ATTR_IEEE_APP_TABLE,
+	DCB_ATTR_IEEE_PEER_ETS,
+	DCB_ATTR_IEEE_PEER_PFC,
+	DCB_ATTR_IEEE_PEER_APP,
 	__DCB_ATTR_IEEE_MAX
 };
 #define DCB_ATTR_IEEE_MAX (__DCB_ATTR_IEEE_MAX - 1)

include/net/dcbnl.h

@@ -43,6 +43,8 @@ struct dcbnl_rtnl_ops {
 	int (*ieee_setpfc) (struct net_device *, struct ieee_pfc *);
 	int (*ieee_getapp) (struct net_device *, struct dcb_app *);
 	int (*ieee_setapp) (struct net_device *, struct dcb_app *);
+	int (*ieee_peer_getets) (struct net_device *, struct ieee_ets *);
+	int (*ieee_peer_getpfc) (struct net_device *, struct ieee_pfc *);
 
 	/* CEE std */
 	u8   (*getstate)(struct net_device *);
@@ -77,6 +79,10 @@ struct dcbnl_rtnl_ops {
 	u8   (*getdcbx)(struct net_device *);
 	u8   (*setdcbx)(struct net_device *, u8);
 
+	/* peer apps */
+	int (*peer_getappinfo)(struct net_device *, struct dcb_peer_app_info *,
+			       u16 *);
+	int (*peer_getapptable)(struct net_device *, struct dcb_app *);
 
 };
 

net/dcb/dcbnl.c

@@ -1224,6 +1224,54 @@ static int dcbnl_ieee_set(struct net_device *netdev, struct nlattr **tb,
 	return err;
 }
 
+static int dcbnl_build_peer_app(struct net_device *netdev, struct sk_buff* skb)
+{
+	struct dcb_peer_app_info info;
+	struct dcb_app *table = NULL;
+	const struct dcbnl_rtnl_ops *ops = netdev->dcbnl_ops;
+	u16 app_count;
+	int err;
+
+
+	/**
+	 * retrieve the peer app configuration form the driver. If the driver
+	 * handlers fail exit without doing anything
+	 */
+	err = ops->peer_getappinfo(netdev, &info, &app_count);
+	if (!err && app_count) {
+		table = kmalloc(sizeof(struct dcb_app) * app_count, GFP_KERNEL);
+		if (!table)
+			return -ENOMEM;
+
+		err = ops->peer_getapptable(netdev, table);
+	}
+
+	if (!err) {
+		u16 i;
+		struct nlattr *app;
+
+		/**
+		 * build the message, from here on the only possible failure
+		 * is due to the skb size
+		 */
+		err = -EMSGSIZE;
+
+		app = nla_nest_start(skb, DCB_ATTR_IEEE_PEER_APP);
+		if (!app)
+			goto nla_put_failure;
+
+		for (i = 0; i < app_count; i++)
+			NLA_PUT(skb, DCB_ATTR_IEEE_APP, sizeof(struct dcb_app),
+				&table[i]);
+
+		nla_nest_end(skb, app);
+	}
+	err = 0;
+
+nla_put_failure:
+	kfree(table);
+	return err;
+}
 
 /* Handle IEEE 802.1Qaz GET commands. */
 static int dcbnl_ieee_get(struct net_device *netdev, struct nlattr **tb,
@@ -1288,6 +1336,27 @@ static int dcbnl_ieee_get(struct net_device *netdev, struct nlattr **tb,
 	spin_unlock(&dcb_lock);
 	nla_nest_end(skb, app);
 
+	/* get peer info if available */
+	if (ops->ieee_peer_getets) {
+		struct ieee_ets ets;
+		err = ops->ieee_peer_getets(netdev, &ets);
+		if (!err)
+			NLA_PUT(skb, DCB_ATTR_IEEE_PEER_ETS, sizeof(ets), &ets);
+	}
+
+	if (ops->ieee_peer_getpfc) {
+		struct ieee_pfc pfc;
+		err = ops->ieee_peer_getpfc(netdev, &pfc);
+		if (!err)
+			NLA_PUT(skb, DCB_ATTR_IEEE_PEER_PFC, sizeof(pfc), &pfc);
+	}
+
+	if (ops->peer_getappinfo && ops->peer_getapptable) {
+		err = dcbnl_build_peer_app(netdev, skb);
+		if (err)
+			goto nla_put_failure;
+	}
+
 	nla_nest_end(skb, ieee);
 	nlmsg_end(skb, nlh);