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Message-Id: <11dcbb7c1219e95dc21d1e3ecb096214f67e44f0.1532953989.git.mkubecek@suse.cz>
Date: Mon, 30 Jul 2018 14:53:17 +0200 (CEST)
From: Michal Kubecek <mkubecek@...e.cz>
To: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Jiri Pirko <jiri@...nulli.us>,
David Miller <davem@...emloft.net>,
Florian Fainelli <f.fainelli@...il.com>,
Roopa Prabhu <roopa@...ulusnetworks.com>,
Jakub Kicinski <kubakici@...pl>,
"John W. Linville" <linville@...driver.com>
Subject: [RFC PATCH net-next v2 07/17] ethtool: implement EVENT notifications
Two types of netlink notifications are introduced: ETHA_EVENT_NEWDEV to
notify about newly registered network devices and ETHA_EVENT_DELDEV to
notify about unregistered network devices. These are triggered by
NETDEV_REGISTER and NETDEV_UNREGISTER notifiers.
These are intended for applications and daemons monitoring ethtool events
to allow updating the list of existing devices without having to open
another socket for rtnetlink.
Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
---
Documentation/networking/ethtool-netlink.txt | 22 ++++++++++
include/uapi/linux/ethtool_netlink.h | 28 +++++++++++++
net/ethtool/netlink.c | 44 ++++++++++++++++++++
3 files changed, 94 insertions(+)
diff --git a/Documentation/networking/ethtool-netlink.txt b/Documentation/networking/ethtool-netlink.txt
index a49dfe3ef4bb..0e83397f2975 100644
--- a/Documentation/networking/ethtool-netlink.txt
+++ b/Documentation/networking/ethtool-netlink.txt
@@ -118,6 +118,8 @@ which the request applies.
List of message types
---------------------
+ ETHNL_CMD_EVENT notification only
+
All constants use ETHNL_CMD_ prefix, usually followed by "GET", "SET" or "ACT"
to indicate the type.
@@ -129,9 +131,29 @@ messages marked as "response only" in the table above. "Get" messages with
NLM_F_DUMP flags and no device identification dump the information for all
devices supporting the request.
+Type ETHNL_CMD_EVENT is special, these messages are never used in userspace
+requests or kernel replies. They are only sent by kernel to sockets listening
+to "monitor" multicast group to inform userspace about certain events.
+
Later sections describe the format and semantics of these request messages.
+EVENT
+-----
+
+EVENT messages are only used in kernel multicast notifications. Atributes
+correspond to specific event types, the same type can appear multiple times.
+
+ ETHA_EVENT_NEWDEV (nested) new device was registered
+ ETHA_NEWDEV_DEV (nested) new device
+ ETHA_EVENT_DELDEV (nested) device was unregistered
+ ETHA_DELDEV_DEV (nested) removed device
+
+Userspace application must expect multiple events to be present in one message
+and also multiple events of the same type (e.g. two or more newly registered
+devices).
+
+
Request translation
-------------------
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 444a668e4a08..f162cd6f80d4 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -7,6 +7,7 @@
enum {
ETHNL_CMD_NOOP,
+ ETHNL_CMD_EVENT, /* only for notifications */
__ETHNL_CMD_MAX,
ETHNL_CMD_MAX = (__ETHNL_CMD_MAX - 1)
@@ -54,6 +55,33 @@ enum {
ETHA_BITSET_MAX = (__ETHA_BITSET_MAX - 1)
};
+/* events */
+
+enum {
+ ETHA_NEWDEV_UNSPEC,
+ ETHA_NEWDEV_DEV, /* nest - ETHA_DEV_* */
+
+ __ETHA_NEWDEV_MAX,
+ ETHA_NEWDEV_MAX = (__ETHA_NEWDEV_MAX - 1)
+};
+
+enum {
+ ETHA_DELDEV_UNSPEC,
+ ETHA_DELDEV_DEV, /* nest - ETHA_DEV_* */
+
+ __ETHA_DELDEV_MAX,
+ ETHA_DELDEV_MAX = (__ETHA_DELDEV_MAX - 1)
+};
+
+enum {
+ ETHA_EVENT_UNSPEC,
+ ETHA_EVENT_NEWDEV, /* nest - ETHA_NEWDEV_* */
+ ETHA_EVENT_DELDEV, /* nest - ETHA_DELDEV_* */
+
+ __ETHA_EVENT_MAX,
+ ETHA_EVENT_MAX = (__ETHA_EVENT_MAX - 1)
+};
+
/* generic netlink info */
#define ETHTOOL_GENL_NAME "ethtool"
#define ETHTOOL_GENL_VERSION 1
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index e4a20bb6c1d4..543560778c80 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -607,6 +607,44 @@ void ethnl_notify(struct net_device *dev, struct netlink_ext_ack *extack,
return __ethnl_notify(ðtool_info);
}
+static unsigned int dev_notify_size(void)
+{
+ return nla_total_size(nla_total_size(nla_total_size(sizeof(u32)) +
+ nla_total_size(IFNAMSIZ)));
+}
+
+static void ethnl_notify_devlist(struct netdev_notifier_info *info,
+ u16 ev_type, u16 dev_attr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(info);
+ struct sk_buff *skb;
+ struct nlattr *nest;
+ void *ehdr;
+ int ret;
+
+ skb = genlmsg_new(dev_notify_size(), GFP_KERNEL);
+ if (!skb)
+ return;
+ ehdr = genlmsg_put(skb, 0, ++ethnl_bcast_seq, ðtool_genl_family, 0,
+ ETHNL_CMD_EVENT);
+ if (!ehdr)
+ goto out_skb;
+ nest = ethnl_nest_start(skb, ev_type);
+ if (!nest)
+ goto out_skb;
+ ret = ethnl_fill_dev(skb, dev, dev_attr);
+ if (ret < 0)
+ goto out_skb;
+ nla_nest_end(skb, nest);
+ genlmsg_end(skb, ehdr);
+
+ genlmsg_multicast(ðtool_genl_family, skb, 0, ETHNL_MCGRP_MONITOR,
+ GFP_KERNEL);
+ return;
+out_skb:
+ nlmsg_free(skb);
+}
+
static int ethnl_netdev_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
@@ -614,6 +652,12 @@ static int ethnl_netdev_event(struct notifier_block *this, unsigned long event,
case NETDEV_ETHTOOL:
__ethnl_notify(ptr);
break;
+ case NETDEV_REGISTER:
+ ethnl_notify_devlist(ptr, ETHA_EVENT_NEWDEV, ETHA_NEWDEV_DEV);
+ break;
+ case NETDEV_UNREGISTER:
+ ethnl_notify_devlist(ptr, ETHA_EVENT_DELDEV, ETHA_DELDEV_DEV);
+ break;
}
return NOTIFY_DONE;
--
2.18.0
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