[PATCH net-next] net/ncsi: Add generic netlink family

[PATCH net-next] net/ncsi: Add generic netlink family

[Samuel Mendoza-Jonas]

Add a generic netlink family for NCSI. This supports two commands;
NCSI_CMD_PKG_INFO which returns information on packages and their
associated channels, and NCSI_CMD_SET_INTERFACE which allows a specific
package or package/channel combination to be set as the preferred
choice.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
---
 include/uapi/linux/ncsi.h | 113 +++++++++++++
 net/ncsi/Makefile         |   2 +-
 net/ncsi/internal.h       |   3 +
 net/ncsi/ncsi-manage.c    |  30 +++-
 net/ncsi/ncsi-netlink.c   | 394 ++++++++++++++++++++++++++++++++++++++++++++++
 net/ncsi/ncsi-netlink.h   |  20 +++
 6 files changed, 557 insertions(+), 5 deletions(-)
 create mode 100644 include/uapi/linux/ncsi.h
 create mode 100644 net/ncsi/ncsi-netlink.c
 create mode 100644 net/ncsi/ncsi-netlink.h

diff --git a/include/uapi/linux/ncsi.h b/include/uapi/linux/ncsi.h
new file mode 100644
index 000000000000..aecab3fb92df
--- /dev/null
+++ b/include/uapi/linux/ncsi.h
@@ -0,0 +1,113 @@
+/*
+ * Copyright Samuel Mendoza-Jonas, IBM Corporation 2018.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __UAPI_NCSI_NETLINK_H__
+#define __UAPI_NCSI_NETLINK_H__
+
+/**
+ * enum ncsi_nl_commands - supported NCSI commands
+ *
+ * @NCSI_CMD_UNSPEC: unspecified command to catch errors
+ * @NCSI_CMD_SET_INTERFACE: set preferred package and channel combination.
+ *	Requires NCSI_ATTR_IFINDEX and the preferred NCSI_ATTR_PACKAGE_ID and
+ *	optionally the preferred NCSI_ATTR_CHANNEL_ID. If neither IDs are
+ *	specified the setting is cleared.
+ * @NCSI_CMD_PKG_INFO: list package and channel attributes. Requires
+ *	NCSI_ATTR_IFINDEX. If NCSI_ATTR_PACKAGE_ID is specified returns the
+ *	specific package and its channels - otherwise a dump request returns
+ *	all packages and their associated channels.
+ * @NCSI_CMD_MAX: highest command number
+ */
+enum ncsi_nl_commands {
+	NCSI_CMD_UNSPEC,
+	NCSI_CMD_SET_INTERFACE,
+	NCSI_CMD_PKG_INFO,
+
+	__NCSI_CMD_AFTER_LAST,
+	NCSI_CMD_MAX = __NCSI_CMD_AFTER_LAST - 1
+};
+
+/**
+ * enum ncsi_nl_attrs - General NCSI netlink attributes
+ *
+ * @NCSI_ATTR_UNSPEC: unspecified attributes to catch errors
+ * @NCSI_ATTR_IFINDEX: ifindex of network device using NCSI
+ * @NCSI_ATTR_PACKAGE_LIST: nested array of NCSI_PKG_ATTR attributes
+ * @NCSI_ATTR_PACKAGE_ID: package ID
+ * @NCSI_ATTR_CHANNEL_ID: channel ID
+ * @NCSI_ATTR_MAX: highest attribute number
+ */
+enum ncsi_nl_attrs {
+	NCSI_ATTR_UNSPEC,
+	NCSI_ATTR_IFINDEX,
+	NCSI_ATTR_PACKAGE_LIST,
+	NCSI_ATTR_PACKAGE_ID,
+	NCSI_ATTR_CHANNEL_ID,
+
+	__NCSI_ATTR_AFTER_LAST,
+	NCSI_ATTR_MAX = __NCSI_ATTR_AFTER_LAST - 1
+};
+
+/**
+ * enum ncsi_nl_pkg_attrs - NCSI netlink package-specific attributes
+ *
+ * @NCSI_PKG_ATTR_UNSPEC: unspecified attributes to catch errors
+ * @NCSI_PKG_ATTR: nested array of package attributes
+ * @NCSI_PKG_ATTR_ID: package ID
+ * @NCSI_PKG_ATTR_FORCED: flag signifying a package has been set as preferred
+ * @NCSI_PKG_ATTR_CHANNEL_LIST: nested array of NCSI_CHANNEL_ATTR attributes
+ * @NCSI_PKG_ATTR_MAX: highest attribute number
+ */
+enum ncsi_nl_pkg_attrs {
+	NCSI_PKG_ATTR_UNSPEC,
+	NCSI_PKG_ATTR,
+	NCSI_PKG_ATTR_ID,
+	NCSI_PKG_ATTR_FORCED,
+	NCSI_PKG_ATTR_CHANNEL_LIST,
+
+	__NCSI_PKG_ATTR_AFTER_LAST,
+	NCSI_PKG_ATTR_MAX = __NCSI_PKG_ATTR_AFTER_LAST - 1
+};
+
+/**
+ * enum ncsi_nl_channel_attrs - NCSI netlink channel-specific attributes
+ *
+ * @NCSI_CHANNEL_ATTR_UNSPEC: unspecified attributes to catch errors
+ * @NCSI_CHANNEL_ATTR: nested array of channel attributes
+ * @NCSI_CHANNEL_ATTR_ID: channel ID
+ * @NCSI_CHANNEL_ATTR_VERSION_MAJOR: channel major version number
+ * @NCSI_CHANNEL_ATTR_VERSION_MINOR: channel minor version number
+ * @NCSI_CHANNEL_ATTR_VERSION_STR: channel version string
+ * @NCSI_CHANNEL_ATTR_LINK_STATE: channel link state flags
+ * @NCSI_CHANNEL_ATTR_ACTIVE: channels with this flag are in
+ *	NCSI_CHANNEL_ACTIVE state
+ * @NCSI_CHANNEL_ATTR_FORCED: flag signifying a channel has been set as
+ *	preferred
+ * @NCSI_CHANNEL_ATTR_VLAN_LIST: nested array of NCSI_CHANNEL_ATTR_VLAN_IDs
+ * @NCSI_CHANNEL_ATTR_VLAN_ID: VLAN ID being filtered on this channel
+ * @NCSI_CHANNEL_ATTR_MAX: highest attribute number
+ */
+enum ncsi_nl_channel_attrs {
+	NCSI_CHANNEL_ATTR_UNSPEC,
+	NCSI_CHANNEL_ATTR,
+	NCSI_CHANNEL_ATTR_ID,
+	NCSI_CHANNEL_ATTR_VERSION_MAJOR,
+	NCSI_CHANNEL_ATTR_VERSION_MINOR,
+	NCSI_CHANNEL_ATTR_VERSION_STR,
+	NCSI_CHANNEL_ATTR_LINK_STATE,
+	NCSI_CHANNEL_ATTR_ACTIVE,
+	NCSI_CHANNEL_ATTR_FORCED,
+	NCSI_CHANNEL_ATTR_VLAN_LIST,
+	NCSI_CHANNEL_ATTR_VLAN_ID,
+
+	__NCSI_CHANNEL_ATTR_AFTER_LAST,
+	NCSI_CHANNEL_ATTR_MAX = __NCSI_CHANNEL_ATTR_AFTER_LAST - 1
+};
+
+#endif /* __UAPI_NCSI_NETLINK_H__ */
diff --git a/net/ncsi/Makefile b/net/ncsi/Makefile
index dd12b564f2e7..436ef68331f2 100644
--- a/net/ncsi/Makefile
+++ b/net/ncsi/Makefile
@@ -1,4 +1,4 @@
 #
 # Makefile for NCSI API
 #
-obj-$(CONFIG_NET_NCSI) += ncsi-cmd.o ncsi-rsp.o ncsi-aen.o ncsi-manage.o
+obj-$(CONFIG_NET_NCSI) += ncsi-cmd.o ncsi-rsp.o ncsi-aen.o ncsi-manage.o ncsi-netlink.o
diff --git a/net/ncsi/internal.h b/net/ncsi/internal.h
index d30f7bd741d0..8da84312cd3b 100644
--- a/net/ncsi/internal.h
+++ b/net/ncsi/internal.h
@@ -276,6 +276,8 @@ struct ncsi_dev_priv {
 	unsigned int        package_num;     /* Number of packages         */
 	struct list_head    packages;        /* List of packages           */
 	struct ncsi_channel *hot_channel;    /* Channel was ever active    */
+	struct ncsi_package *force_package;  /* Force a specific package   */
+	struct ncsi_channel *force_channel;  /* Force a specific channel   */
 	struct ncsi_request requests[256];   /* Request table              */
 	unsigned int        request_id;      /* Last used request ID       */
 #define NCSI_REQ_START_IDX	1
@@ -318,6 +320,7 @@ extern spinlock_t ncsi_dev_lock;
 	list_for_each_entry_rcu(nc, &np->channels, node)
 
 /* Resources */
+u32 *ncsi_get_filter(struct ncsi_channel *nc, int table, int index);
 int ncsi_find_filter(struct ncsi_channel *nc, int table, void *data);
 int ncsi_add_filter(struct ncsi_channel *nc, int table, void *data);
 int ncsi_remove_filter(struct ncsi_channel *nc, int table, int index);
diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index c989211bbabc..c3695ba0cf94 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -12,7 +12,6 @@
 #include <linux/init.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
-#include <linux/netlink.h>
 
 #include <net/ncsi.h>
 #include <net/net_namespace.h>
@@ -23,6 +22,7 @@
 
 #include "internal.h"
 #include "ncsi-pkt.h"
+#include "ncsi-netlink.h"
 
 LIST_HEAD(ncsi_dev_list);
 DEFINE_SPINLOCK(ncsi_dev_lock);
@@ -38,7 +38,7 @@ static inline int ncsi_filter_size(int table)
 	return sizes[table];
 }
 
-static u32 *ncsi_get_filter(struct ncsi_channel *nc, int table, int index)
+u32 *ncsi_get_filter(struct ncsi_channel *nc, int table, int index)
 {
 	struct ncsi_channel_filter *ncf;
 	int size;
@@ -965,20 +965,37 @@ static void ncsi_configure_channel(struct ncsi_dev_priv *ndp)
 
 static int ncsi_choose_active_channel(struct ncsi_dev_priv *ndp)
 {
-	struct ncsi_package *np;
-	struct ncsi_channel *nc, *found, *hot_nc;
+	struct ncsi_package *np, *force_package;
+	struct ncsi_channel *nc, *found, *hot_nc, *force_channel;
 	struct ncsi_channel_mode *ncm;
 	unsigned long flags;
 
 	spin_lock_irqsave(&ndp->lock, flags);
 	hot_nc = ndp->hot_channel;
+	force_channel = ndp->force_channel;
+	force_package = ndp->force_package;
 	spin_unlock_irqrestore(&ndp->lock, flags);
 
+	/* Force a specific channel whether or not it has link if we have been
+	 * configured to do so
+	 */
+	if (force_package && force_channel) {
+		found = force_channel;
+		ncm = &found->modes[NCSI_MODE_LINK];
+		if (!(ncm->data[2] & 0x1))
+			netdev_info(ndp->ndev.dev,
+				    "NCSI: Channel %u forced, but it is link down\n",
+				    found->id);
+		goto out;
+	}
+
 	/* The search is done once an inactive channel with up
 	 * link is found.
 	 */
 	found = NULL;
 	NCSI_FOR_EACH_PACKAGE(ndp, np) {
+		if (ndp->force_package && np != ndp->force_package)
+			continue;
 		NCSI_FOR_EACH_CHANNEL(np, nc) {
 			spin_lock_irqsave(&nc->lock, flags);
 
@@ -1594,6 +1611,9 @@ struct ncsi_dev *ncsi_register_dev(struct net_device *dev,
 	ndp->ptype.dev = dev;
 	dev_add_pack(&ndp->ptype);
 
+	/* Set up generic netlink interface */
+	ncsi_init_netlink(dev);
+
 	return nd;
 }
 EXPORT_SYMBOL_GPL(ncsi_register_dev);
@@ -1673,6 +1693,8 @@ void ncsi_unregister_dev(struct ncsi_dev *nd)
 #endif
 	spin_unlock_irqrestore(&ncsi_dev_lock, flags);
 
+	ncsi_unregister_netlink(nd->dev);
+
 	kfree(ndp);
 }
 EXPORT_SYMBOL_GPL(ncsi_unregister_dev);
diff --git a/net/ncsi/ncsi-netlink.c b/net/ncsi/ncsi-netlink.c
new file mode 100644
index 000000000000..ab9e59db7197
--- /dev/null
+++ b/net/ncsi/ncsi-netlink.c
@@ -0,0 +1,394 @@
+/*
+ * Copyright Samuel Mendoza-Jonas, IBM Corporation 2018.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/if_arp.h>
+#include <linux/rtnetlink.h>
+#include <linux/etherdevice.h>
+#include <linux/module.h>
+#include <net/genetlink.h>
+#include <net/ncsi.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <uapi/linux/ncsi.h>
+
+#include "internal.h"
+#include "ncsi-netlink.h"
+
+static struct genl_family ncsi_genl_family;
+
+static const struct nla_policy ncsi_genl_policy[NCSI_ATTR_MAX + 1] = {
+	[NCSI_ATTR_IFINDEX] =		{ .type = NLA_U32 },
+	[NCSI_ATTR_PACKAGE_LIST] =	{ .type = NLA_NESTED },
+	[NCSI_ATTR_PACKAGE_ID] =	{ .type = NLA_U32 },
+	[NCSI_ATTR_CHANNEL_ID] =	{ .type = NLA_U32 },
+};
+
+static struct ncsi_dev_priv *ndp_from_ifindex(struct net *net, u32 ifindex)
+{
+	struct ncsi_dev_priv *ndp;
+	struct net_device *dev;
+	struct ncsi_dev *nd;
+	struct ncsi_dev;
+
+	if (!net)
+		return NULL;
+
+	dev = dev_get_by_index(net, ifindex);
+	if (!dev) {
+		pr_err("NCSI netlink: No device for ifindex %u\n", ifindex);
+		return NULL;
+	}
+
+	nd = ncsi_find_dev(dev);
+	ndp = nd ? TO_NCSI_DEV_PRIV(nd) : NULL;
+
+	dev_put(dev);
+	return ndp;
+}
+
+static int ncsi_write_channel_info(struct sk_buff *skb,
+				   struct ncsi_dev_priv *ndp,
+				   struct ncsi_channel *nc)
+{
+	struct nlattr *vid_nest;
+	struct ncsi_channel_filter *ncf;
+	struct ncsi_channel_mode *m;
+	u32 *data;
+	int i;
+
+	nla_put_u32(skb, NCSI_CHANNEL_ATTR_ID, nc->id);
+	m = &nc->modes[NCSI_MODE_LINK];
+	nla_put_u32(skb, NCSI_CHANNEL_ATTR_LINK_STATE, m->data[2]);
+	if (nc->state == NCSI_CHANNEL_ACTIVE)
+		nla_put_flag(skb, NCSI_CHANNEL_ATTR_ACTIVE);
+	if (ndp->force_channel == nc)
+		nla_put_flag(skb, NCSI_CHANNEL_ATTR_FORCED);
+
+	nla_put_u32(skb, NCSI_CHANNEL_ATTR_VERSION_MAJOR, nc->version.version);
+	nla_put_u32(skb, NCSI_CHANNEL_ATTR_VERSION_MINOR, nc->version.alpha2);
+	nla_put_string(skb, NCSI_CHANNEL_ATTR_VERSION_STR, nc->version.fw_name);
+
+	vid_nest = nla_nest_start(skb, NCSI_CHANNEL_ATTR_VLAN_LIST);
+	if (!vid_nest)
+		return -ENOMEM;
+	ncf = nc->filters[NCSI_FILTER_VLAN];
+	i = -1;
+	if (ncf) {
+		while ((i = find_next_bit((void *)&ncf->bitmap, ncf->total,
+					  i + 1)) < ncf->total) {
+			data = ncsi_get_filter(nc, NCSI_FILTER_VLAN, i);
+			/* Uninitialised channels will have 'zero' vlan ids */
+			if (!data || !*data)
+				continue;
+			nla_put_u16(skb, NCSI_CHANNEL_ATTR_VLAN_ID,
+				    *(u16 *)data);
+		}
+	}
+	nla_nest_end(skb, vid_nest);
+
+	return 0;
+}
+
+static int ncsi_write_package_info(struct sk_buff *skb,
+				   struct ncsi_dev_priv *ndp, unsigned int id)
+{
+	struct nlattr *pnest, *cnest, *nest;
+	struct ncsi_package *np;
+	struct ncsi_channel *nc;
+	bool found;
+	int rc;
+
+	if (id > ndp->package_num) {
+		netdev_info(ndp->ndev.dev, "NCSI: No package with id %u\n", id);
+		return -ENODEV;
+	}
+
+	found = false;
+	NCSI_FOR_EACH_PACKAGE(ndp, np) {
+		if (np->id != id)
+			continue;
+		pnest = nla_nest_start(skb, NCSI_PKG_ATTR);
+		if (!pnest)
+			return -ENOMEM;
+		nla_put_u32(skb, NCSI_PKG_ATTR_ID, np->id);
+		if (ndp->force_package == np)
+			nla_put_flag(skb, NCSI_PKG_ATTR_FORCED);
+		cnest = nla_nest_start(skb, NCSI_PKG_ATTR_CHANNEL_LIST);
+		if (!cnest) {
+			nla_nest_cancel(skb, pnest);
+			return -ENOMEM;
+		}
+		NCSI_FOR_EACH_CHANNEL(np, nc) {
+			nest = nla_nest_start(skb, NCSI_CHANNEL_ATTR);
+			if (!nest) {
+				nla_nest_cancel(skb, cnest);
+				nla_nest_cancel(skb, pnest);
+				return -ENOMEM;
+			}
+			rc = ncsi_write_channel_info(skb, ndp, nc);
+			if (rc) {
+				nla_nest_cancel(skb, nest);
+				nla_nest_cancel(skb, cnest);
+				nla_nest_cancel(skb, pnest);
+				return rc;
+			}
+			nla_nest_end(skb, nest);
+		}
+		nla_nest_end(skb, cnest);
+		nla_nest_end(skb, pnest);
+		found = true;
+	}
+
+	if (!found)
+		return -ENODEV;
+
+	return 0;
+}
+
+static int ncsi_pkg_info_nl(struct sk_buff *msg, struct genl_info *info)
+{
+	struct ncsi_dev_priv *ndp;
+	unsigned int package_id;
+	struct sk_buff *skb;
+	struct nlattr *attr;
+	void *hdr;
+	int rc;
+
+	if (!info || !info->attrs)
+		return -EINVAL;
+
+	if (!info->attrs[NCSI_ATTR_IFINDEX])
+		return -EINVAL;
+
+	if (!info->attrs[NCSI_ATTR_PACKAGE_ID])
+		return -EINVAL;
+
+	ndp = ndp_from_ifindex(genl_info_net(info),
+			       nla_get_u32(info->attrs[NCSI_ATTR_IFINDEX]));
+	if (!ndp)
+		return -ENODEV;
+
+	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(skb, info->snd_portid, info->snd_seq,
+			  &ncsi_genl_family, 0, NCSI_CMD_PKG_INFO);
+	if (!hdr) {
+		kfree(skb);
+		return -EMSGSIZE;
+	}
+
+	package_id = nla_get_u32(info->attrs[NCSI_ATTR_PACKAGE_ID]);
+
+	attr = nla_nest_start(skb, NCSI_ATTR_PACKAGE_LIST);
+	rc = ncsi_write_package_info(skb, ndp, package_id);
+
+	if (rc) {
+		nla_nest_cancel(skb, attr);
+		goto err;
+	}
+
+	nla_nest_end(skb, attr);
+
+	genlmsg_end(skb, hdr);
+	return genlmsg_reply(skb, info);
+
+err:
+	genlmsg_cancel(skb, hdr);
+	kfree(skb);
+	return rc;
+}
+
+static int ncsi_pkg_info_all_nl(struct sk_buff *skb,
+				struct netlink_callback *cb)
+{
+	struct nlattr *attrs[NCSI_ATTR_MAX];
+	struct ncsi_package *np, *package;
+	struct ncsi_dev_priv *ndp;
+	unsigned int package_id;
+	struct nlattr *attr;
+	void *hdr;
+	int rc;
+
+	rc = genlmsg_parse(cb->nlh, &ncsi_genl_family, attrs, NCSI_ATTR_MAX,
+			   ncsi_genl_policy, NULL);
+	if (rc)
+		return rc;
+
+	if (!attrs[NCSI_ATTR_IFINDEX])
+		return -EINVAL;
+
+	ndp = ndp_from_ifindex(get_net(sock_net(skb->sk)),
+			       nla_get_u32(attrs[NCSI_ATTR_IFINDEX]));
+
+	if (!ndp)
+		return -ENODEV;
+
+	package_id = cb->args[0];
+	package = NULL;
+	NCSI_FOR_EACH_PACKAGE(ndp, np)
+		if (np->id == package_id)
+			package = np;
+
+	if (!package)
+		return 0; /* done */
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &ncsi_genl_family, 0,  NCSI_CMD_PKG_INFO);
+	if (!hdr) {
+		rc = -EMSGSIZE;
+		goto err;
+	}
+
+	attr = nla_nest_start(skb, NCSI_ATTR_PACKAGE_LIST);
+	rc = ncsi_write_package_info(skb, ndp, package->id);
+	if (rc) {
+		nla_nest_cancel(skb, attr);
+		goto err;
+	}
+
+	nla_nest_end(skb, attr);
+	genlmsg_end(skb, hdr);
+
+	cb->args[0] = package_id + 1;
+
+	return skb->len;
+err:
+	genlmsg_cancel(skb, hdr);
+	return rc;
+}
+
+static int ncsi_set_interface_nl(struct sk_buff *msg, struct genl_info *info)
+{
+	struct ncsi_package *np, *package;
+	struct ncsi_channel *nc, *channel;
+	u32 package_id, channel_id;
+	struct ncsi_dev_priv *ndp;
+	unsigned long flags;
+
+	if (!info || !info->attrs)
+		return -EINVAL;
+
+	if (!info->attrs[NCSI_ATTR_IFINDEX])
+		return -EINVAL;
+
+	ndp = ndp_from_ifindex(get_net(sock_net(msg->sk)),
+			       nla_get_u32(info->attrs[NCSI_ATTR_IFINDEX]));
+	if (!ndp)
+		return -ENODEV;
+
+	if (!info->attrs[NCSI_ATTR_PACKAGE_ID]) {
+		/* Clear any override */
+		spin_lock_irqsave(&ndp->lock, flags);
+		ndp->force_package = NULL;
+		ndp->force_channel = NULL;
+		spin_unlock_irqrestore(&ndp->lock, flags);
+		netdev_info(ndp->ndev.dev,
+			    "NCSI: Cleared preferred package/channel\n");
+		goto done;
+	}
+
+	package_id = nla_get_u32(info->attrs[NCSI_ATTR_PACKAGE_ID]);
+	package = NULL;
+
+	spin_lock_irqsave(&ndp->lock, flags);
+
+	NCSI_FOR_EACH_PACKAGE(ndp, np)
+		if (np->id == package_id)
+			package = np;
+	if (!package) {
+		/* The user has set a package that does not exist */
+		return -ERANGE;
+	}
+
+	channel = NULL;
+	if (!info->attrs[NCSI_ATTR_CHANNEL_ID]) {
+		/* Allow any channel */
+		channel_id = NCSI_RESERVED_CHANNEL;
+	} else {
+		channel_id = nla_get_u32(info->attrs[NCSI_ATTR_CHANNEL_ID]);
+		NCSI_FOR_EACH_CHANNEL(package, nc)
+			if (nc->id == channel_id)
+				channel = nc;
+	}
+
+	if (channel_id != NCSI_RESERVED_CHANNEL && !channel) {
+		/* The user has set a channel that does not exist on this
+		 * package
+		 */
+		netdev_info(ndp->ndev.dev, "NCSI: Channel %u does not exist!\n",
+			    channel_id);
+		return -ERANGE;
+	}
+
+	ndp->force_package = package;
+	ndp->force_channel = channel;
+	spin_unlock_irqrestore(&ndp->lock, flags);
+
+	netdev_info(ndp->ndev.dev, "Set package 0x%x, channel 0x%x%s as preferred\n",
+		    package_id, channel_id,
+		    channel_id == NCSI_RESERVED_CHANNEL ? " (any)" : "");
+
+done:
+	/* Bounce the NCSI channel to set changes */
+	ncsi_stop_dev(&ndp->ndev);
+	ncsi_start_dev(&ndp->ndev);
+
+	return 0;
+}
+
+static const struct genl_ops ncsi_ops[] = {
+	{
+		.cmd = NCSI_CMD_SET_INTERFACE,
+		.policy = ncsi_genl_policy,
+		.doit = ncsi_set_interface_nl,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = NCSI_CMD_PKG_INFO,
+		.policy = ncsi_genl_policy,
+		.doit = ncsi_pkg_info_nl,
+		.dumpit = ncsi_pkg_info_all_nl,
+		.flags = 0,
+	},
+};
+
+static struct genl_family ncsi_genl_family __ro_after_init = {
+	.name = "NCSI",
+	.version = 0,
+	.maxattr = NCSI_ATTR_MAX,
+	.module = THIS_MODULE,
+	.ops = ncsi_ops,
+	.n_ops = ARRAY_SIZE(ncsi_ops),
+};
+
+int ncsi_init_netlink(struct net_device *dev)
+{
+	int rc;
+
+	rc = genl_register_family(&ncsi_genl_family);
+	if (rc)
+		netdev_err(dev, "ncsi: failed to register netlink family\n");
+
+	return rc;
+}
+
+int ncsi_unregister_netlink(struct net_device *dev)
+{
+	int rc;
+
+	rc = genl_unregister_family(&ncsi_genl_family);
+	if (rc)
+		netdev_err(dev, "ncsi: failed to unregister netlink family\n");
+
+	return rc;
+}
diff --git a/net/ncsi/ncsi-netlink.h b/net/ncsi/ncsi-netlink.h
new file mode 100644
index 000000000000..91a5c256f8c4
--- /dev/null
+++ b/net/ncsi/ncsi-netlink.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright Samuel Mendoza-Jonas, IBM Corporation 2018.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __NCSI_NETLINK_H__
+#define __NCSI_NETLINK_H__
+
+#include <linux/netdevice.h>
+
+#include "internal.h"
+
+int ncsi_init_netlink(struct net_device *dev);
+int ncsi_unregister_netlink(struct net_device *dev);
+
+#endif /* __NCSI_NETLINK_H__ */
-- 
2.16.2

Re: [PATCH net-next] net/ncsi: Add generic netlink family

[David Miller]

From: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Date: Fri, 23 Feb 2018 15:15:18 +1100

> + * @NCSI_CMD_SET_INTERFACE: set preferred package and channel combination.
> + *	Requires NCSI_ATTR_IFINDEX and the preferred NCSI_ATTR_PACKAGE_ID and
> + *	optionally the preferred NCSI_ATTR_CHANNEL_ID. If neither IDs are
> + *	specified the setting is cleared.

I think clearing the setting when the required attributes are missing
is dangerous behavior.

It is ambiguous whether the user intended the setting to be cleared,
or was in error and forgot to supply the attribute due to a bug.

Re: [PATCH net-next] net/ncsi: Add generic netlink family

[Samuel Mendoza-Jonas]

On Mon, 2018-02-26 at 11:31 -0500, David Miller wrote:
> From: Samuel Mendoza-Jonas <sam@mendozajonas.com>
> Date: Fri, 23 Feb 2018 15:15:18 +1100
> 
> > + * @NCSI_CMD_SET_INTERFACE: set preferred package and channel combination.
> > + *   Requires NCSI_ATTR_IFINDEX and the preferred NCSI_ATTR_PACKAGE_ID and
> > + *   optionally the preferred NCSI_ATTR_CHANNEL_ID. If neither IDs are
> > + *   specified the setting is cleared.
> 
> I think clearing the setting when the required attributes are missing
> is dangerous behavior.
> 
> It is ambiguous whether the user intended the setting to be cleared,
> or was in error and forgot to supply the attribute due to a bug.

Fair point - I'll change this to be an error and add a separate command
to clear the setting explicitly.
In that vein is having NCSI_ATTR_CHANNEL_ID as an optional parameter
ambiguous enough to justify a separate command as well?

Regards,
Sam

Re: [PATCH net-next] net/ncsi: Add generic netlink family

[Samuel Mendoza-Jonas]

On Mon, 2018-02-26 at 11:31 -0500, David Miller wrote:
> From: Samuel Mendoza-Jonas <sam@mendozajonas.com>
> Date: Fri, 23 Feb 2018 15:15:18 +1100
> 
> > + * @NCSI_CMD_SET_INTERFACE: set preferred package and channel combination.
> > + *   Requires NCSI_ATTR_IFINDEX and the preferred NCSI_ATTR_PACKAGE_ID and
> > + *   optionally the preferred NCSI_ATTR_CHANNEL_ID. If neither IDs are
> > + *   specified the setting is cleared.
> 
> I think clearing the setting when the required attributes are missing
> is dangerous behavior.
> 
> It is ambiguous whether the user intended the setting to be cleared,
> or was in error and forgot to supply the attribute due to a bug.

Fair point - I'll change this to be an error and add a separate command
to clear the setting explicitly.
In that vein is having NCSI_ATTR_CHANNEL_ID as an optional parameter
ambiguous enough to justify a separate command as well?

Regards,
Sam