netdev-genl: Add netlink framework functions for queue

Implement the netdev netlink framework functions for
exposing queue information.

Signed-off-by: Amritha Nambiar <amritha.nambiar@intel.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://lore.kernel.org/r/170147332603.5260.7982559672617639065.stgit@anambiarhost.jf.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/netdev-genl.c

@@ -7,9 +7,23 @@
 #include <net/sock.h>
 #include <net/xdp.h>
 #include <net/xdp_sock.h>
+#include <net/netdev_rx_queue.h>
 
 #include "netdev-genl-gen.h"
 
+struct netdev_nl_dump_ctx {
+	unsigned long	ifindex;
+	unsigned int	rxq_idx;
+	unsigned int	txq_idx;
+};
+
+static struct netdev_nl_dump_ctx *netdev_dump_ctx(struct netlink_callback *cb)
+{
+	NL_ASSERT_DUMP_CTX_FITS(struct netdev_nl_dump_ctx);
+
+	return (struct netdev_nl_dump_ctx *)cb->ctx;
+}
+
 static int
 netdev_nl_dev_fill(struct net_device *netdev, struct sk_buff *rsp,
 		   const struct genl_info *info)
@@ -122,12 +136,13 @@ int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info)
 
 int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb);
 	struct net *net = sock_net(skb->sk);
 	struct net_device *netdev;
 	int err = 0;
 
 	rtnl_lock();
-	for_each_netdev_dump(net, netdev, cb->args[0]) {
+	for_each_netdev_dump(net, netdev, ctx->ifindex) {
 		err = netdev_nl_dev_fill(netdev, skb, genl_info_dump(cb));
 		if (err < 0)
 			break;
@@ -140,14 +155,180 @@ int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+static int
+netdev_nl_queue_fill_one(struct sk_buff *rsp, struct net_device *netdev,
+			 u32 q_idx, u32 q_type, const struct genl_info *info)
+{
+	struct netdev_rx_queue *rxq;
+	struct netdev_queue *txq;
+	void *hdr;
+
+	hdr = genlmsg_iput(rsp, info);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(rsp, NETDEV_A_QUEUE_ID, q_idx) ||
+	    nla_put_u32(rsp, NETDEV_A_QUEUE_TYPE, q_type) ||
+	    nla_put_u32(rsp, NETDEV_A_QUEUE_IFINDEX, netdev->ifindex))
+		goto nla_put_failure;
+
+	switch (q_type) {
+	case NETDEV_QUEUE_TYPE_RX:
+		rxq = __netif_get_rx_queue(netdev, q_idx);
+		if (rxq->napi && nla_put_u32(rsp, NETDEV_A_QUEUE_NAPI_ID,
+					     rxq->napi->napi_id))
+			goto nla_put_failure;
+		break;
+	case NETDEV_QUEUE_TYPE_TX:
+		txq = netdev_get_tx_queue(netdev, q_idx);
+		if (txq->napi && nla_put_u32(rsp, NETDEV_A_QUEUE_NAPI_ID,
+					     txq->napi->napi_id))
+			goto nla_put_failure;
+	}
+
+	genlmsg_end(rsp, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(rsp, hdr);
+	return -EMSGSIZE;
+}
+
+static int netdev_nl_queue_validate(struct net_device *netdev, u32 q_id,
+				    u32 q_type)
+{
+	switch (q_type) {
+	case NETDEV_QUEUE_TYPE_RX:
+		if (q_id >= netdev->real_num_rx_queues)
+			return -EINVAL;
+		return 0;
+	case NETDEV_QUEUE_TYPE_TX:
+		if (q_id >= netdev->real_num_tx_queues)
+			return -EINVAL;
+	}
+	return 0;
+}
+
+static int
+netdev_nl_queue_fill(struct sk_buff *rsp, struct net_device *netdev, u32 q_idx,
+		     u32 q_type, const struct genl_info *info)
+{
+	int err = 0;
+
+	if (!(netdev->flags & IFF_UP))
+		return err;
+
+	err = netdev_nl_queue_validate(netdev, q_idx, q_type);
+	if (err)
+		return err;
+
+	return netdev_nl_queue_fill_one(rsp, netdev, q_idx, q_type, info);
+}
+
 int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info)
 {
-	return -EOPNOTSUPP;
+	u32 q_id, q_type, ifindex;
+	struct net_device *netdev;
+	struct sk_buff *rsp;
+	int err;
+
+	if (GENL_REQ_ATTR_CHECK(info, NETDEV_A_QUEUE_ID) ||
+	    GENL_REQ_ATTR_CHECK(info, NETDEV_A_QUEUE_TYPE) ||
+	    GENL_REQ_ATTR_CHECK(info, NETDEV_A_QUEUE_IFINDEX))
+		return -EINVAL;
+
+	q_id = nla_get_u32(info->attrs[NETDEV_A_QUEUE_ID]);
+	q_type = nla_get_u32(info->attrs[NETDEV_A_QUEUE_TYPE]);
+	ifindex = nla_get_u32(info->attrs[NETDEV_A_QUEUE_IFINDEX]);
+
+	rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!rsp)
+		return -ENOMEM;
+
+	rtnl_lock();
+
+	netdev = __dev_get_by_index(genl_info_net(info), ifindex);
+	if (netdev)
+		err = netdev_nl_queue_fill(rsp, netdev, q_id, q_type, info);
+	else
+		err = -ENODEV;
+
+	rtnl_unlock();
+
+	if (err)
+		goto err_free_msg;
+
+	return genlmsg_reply(rsp, info);
+
+err_free_msg:
+	nlmsg_free(rsp);
+	return err;
+}
+
+static int
+netdev_nl_queue_dump_one(struct net_device *netdev, struct sk_buff *rsp,
+			 const struct genl_info *info,
+			 struct netdev_nl_dump_ctx *ctx)
+{
+	int err = 0;
+	int i;
+
+	if (!(netdev->flags & IFF_UP))
+		return err;
+
+	for (i = ctx->rxq_idx; i < netdev->real_num_rx_queues;) {
+		err = netdev_nl_queue_fill_one(rsp, netdev, i,
+					       NETDEV_QUEUE_TYPE_RX, info);
+		if (err)
+			return err;
+		ctx->rxq_idx = i++;
+	}
+	for (i = ctx->txq_idx; i < netdev->real_num_tx_queues;) {
+		err = netdev_nl_queue_fill_one(rsp, netdev, i,
+					       NETDEV_QUEUE_TYPE_TX, info);
+		if (err)
+			return err;
+		ctx->txq_idx = i++;
+	}
+
+	return err;
 }
 
 int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	return -EOPNOTSUPP;
+	struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb);
+	const struct genl_info *info = genl_info_dump(cb);
+	struct net *net = sock_net(skb->sk);
+	struct net_device *netdev;
+	u32 ifindex = 0;
+	int err = 0;
+
+	if (info->attrs[NETDEV_A_QUEUE_IFINDEX])
+		ifindex = nla_get_u32(info->attrs[NETDEV_A_QUEUE_IFINDEX]);
+
+	rtnl_lock();
+	if (ifindex) {
+		netdev = __dev_get_by_index(net, ifindex);
+		if (netdev)
+			err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
+		else
+			err = -ENODEV;
+	} else {
+		for_each_netdev_dump(net, netdev, ctx->ifindex) {
+			err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
+			if (err < 0)
+				break;
+			ctx->rxq_idx = 0;
+			ctx->txq_idx = 0;
+		}
+	}
+	rtnl_unlock();
+
+	if (err != -EMSGSIZE)
+		return err;
+
+	return skb->len;
 }
 
 static int netdev_genl_netdevice_event(struct notifier_block *nb,