[PATCH net-next v2 1/6] net: dcb: add new pcp selector to app object

[Daniel Machon]

Add new PCP selector for the 8021Qaz APP managed object.

As the PCP selector is not part of the 8021Qaz standard, a new non-std
extension attribute DCB_ATTR_DCB_APP has been introduced. Also two
helper functions to translate between selector and app attribute type
has been added.

The purpose of adding the PCP selector, is to be able to offload
PCP-based queue classification to the 8021Q Priority Code Point table,
see 6.9.3 of IEEE Std 802.1Q-2018.

PCP and DEI is encoded in the protocol field as 8*dei+pcp, so that a
mapping of PCP 2 and DEI 1 to priority 3 is encoded as {255, 10, 3}.

Signed-off-by: Daniel Machon <daniel.machon@xxxxxxxxxxxxx>
---
 include/uapi/linux/dcbnl.h |  6 +++++
 net/dcb/dcbnl.c            | 49 ++++++++++++++++++++++++++++++++++----
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/dcbnl.h b/include/uapi/linux/dcbnl.h
index a791a94013a6..9f68dc501cc1 100644
--- a/include/uapi/linux/dcbnl.h
+++ b/include/uapi/linux/dcbnl.h
@@ -218,6 +218,9 @@ struct cee_pfc {
 #define IEEE_8021QAZ_APP_SEL_ANY	4
 #define IEEE_8021QAZ_APP_SEL_DSCP       5

+/* Non-std selector values */
+#define DCB_APP_SEL_PCP		24
+
 /* This structure contains the IEEE 802.1Qaz APP managed object. This
  * object is also used for the CEE std as well.
  *
@@ -247,6 +250,8 @@ struct dcb_app {
 	__u16	protocol;
 };

+#define IEEE_8021QAZ_APP_SEL_MAX 255
+
 /**
  * struct dcb_peer_app_info - APP feature information sent by the peer
  *
@@ -425,6 +430,7 @@ enum ieee_attrs {
 enum ieee_attrs_app {
 	DCB_ATTR_IEEE_APP_UNSPEC,
 	DCB_ATTR_IEEE_APP,
+	DCB_ATTR_DCB_APP,
 	__DCB_ATTR_IEEE_APP_MAX
 };
 #define DCB_ATTR_IEEE_APP_MAX (__DCB_ATTR_IEEE_APP_MAX - 1)
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index dc4fb699b56c..580d26acfc84 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -179,6 +179,46 @@ static const struct nla_policy dcbnl_featcfg_nest[DCB_FEATCFG_ATTR_MAX + 1] = {
 static LIST_HEAD(dcb_app_list);
 static DEFINE_SPINLOCK(dcb_lock);

+static int dcbnl_app_attr_type_get(u8 selector)
+{
+	enum ieee_attrs_app type;
+
+	switch (selector) {
+	case IEEE_8021QAZ_APP_SEL_ETHERTYPE:
+	case IEEE_8021QAZ_APP_SEL_STREAM:
+	case IEEE_8021QAZ_APP_SEL_DGRAM:
+	case IEEE_8021QAZ_APP_SEL_ANY:
+	case IEEE_8021QAZ_APP_SEL_DSCP:
+		type = DCB_ATTR_IEEE_APP;
+		break;
+	case DCB_APP_SEL_PCP:
+		type = DCB_ATTR_DCB_APP;
+		break;
+	default:
+		type = DCB_ATTR_IEEE_APP_UNSPEC;
+		break;
+	}
+
+	return type;
+}
+
+static int dcbnl_app_attr_type_validate(enum ieee_attrs_app type)
+{
+	bool ret;
+
+	switch (type) {
+	case DCB_ATTR_IEEE_APP:
+	case DCB_ATTR_DCB_APP:
+		ret = true;
+		break;
+	default:
+		ret = false;
+		break;
+	}
+
+	return ret;
+}
+
 static struct sk_buff *dcbnl_newmsg(int type, u8 cmd, u32 port, u32 seq,
 				    u32 flags, struct nlmsghdr **nlhp)
 {
@@ -1116,8 +1156,9 @@ static int dcbnl_ieee_fill(struct sk_buff *skb, struct net_device *netdev)
 	spin_lock_bh(&dcb_lock);
 	list_for_each_entry(itr, &dcb_app_list, list) {
 		if (itr->ifindex == netdev->ifindex) {
-			err = nla_put(skb, DCB_ATTR_IEEE_APP, sizeof(itr->app),
-					 &itr->app);
+			enum ieee_attrs_app type =
+				dcbnl_app_attr_type_get(itr->app.selector);
+			err = nla_put(skb, type, sizeof(itr->app), &itr->app);
 			if (err) {
 				spin_unlock_bh(&dcb_lock);
 				return -EMSGSIZE;
@@ -1495,7 +1536,7 @@ static int dcbnl_ieee_set(struct net_device *netdev, struct nlmsghdr *nlh,
 		nla_for_each_nested(attr, ieee[DCB_ATTR_IEEE_APP_TABLE], rem) {
 			struct dcb_app *app_data;

-			if (nla_type(attr) != DCB_ATTR_IEEE_APP)
+			if (!dcbnl_app_attr_type_validate(nla_type(attr)))
 				continue;

 			if (nla_len(attr) < sizeof(struct dcb_app)) {
@@ -1556,7 +1597,7 @@ static int dcbnl_ieee_del(struct net_device *netdev, struct nlmsghdr *nlh,
 		nla_for_each_nested(attr, ieee[DCB_ATTR_IEEE_APP_TABLE], rem) {
 			struct dcb_app *app_data;

-			if (nla_type(attr) != DCB_ATTR_IEEE_APP)
+			if (!dcbnl_app_attr_type_validate(nla_type(attr)))
 				continue;
 			app_data = nla_data(attr);
 			if (ops->ieee_delapp)
--
2.34.1