[PATCH net-next 0/2] rtnetlink: Updates to rtnetlink_event()

[PATCH net-next 0/2] rtnetlink: Updates to rtnetlink_event()

[Vladislav Yasevich]

This series came out of the conversation that started as a result
my first attempt to add netdevice event info to netlink messages.

This series converts event processing to a 'white list', where
we explicitely permit events to generate netlink messages.  This
is meant to make people take a closer look and determine wheter
these events should really trigger netlink messages.

I am also adding a V2 of my patch to add event type to the netlink
message.  This version supports all events that we currently generate.

I will also update my patch to iproute that will show this data
through 'ip monitor'. 

I actually need the ability to trap NETDEV_NOTIFY_PEERS event
(as well as possible NETDEV_RESEND_IGMP) to support hanlding of
macvtap on top of bonding.  I hope others will also find this info usefull.

Vladislav Yasevich (2):
  rtnetlink: Convert rtnetlink_event to white list
  rtnl: Add support for netdev event to link messages

 include/linux/rtnetlink.h    |   3 +-
 include/uapi/linux/if_link.h |  19 ++++++++
 net/core/dev.c               |   2 +-
 net/core/rtnetlink.c         | 113 ++++++++++++++++++++++++++++++++++---------
 4 files changed, 113 insertions(+), 24 deletions(-)

-- 
2.7.4

[PATCH net-next 1/2] rtnetlink: Convert rtnetlink_event to white list

[Vladislav Yasevich]

The rtnetlink_event currently functions as a blacklist where
we block cerntain netdev events from being sent to user space.
As a result, events have been added to the system that userspace
probably doesn't care about.

This patch converts the implementation to the white list so that
newly events would have to be specifically added to the list to
be sent to userspace.  This would force new event implementers to
consider whether a given event is usefull to user space or if it's
just a kernel event.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
---
 net/core/rtnetlink.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9c3947a..f48a60d 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -4116,22 +4116,23 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
 	switch (event) {
-	case NETDEV_UP:
-	case NETDEV_DOWN:
-	case NETDEV_PRE_UP:
-	case NETDEV_POST_INIT:
-	case NETDEV_REGISTER:
-	case NETDEV_CHANGE:
-	case NETDEV_PRE_TYPE_CHANGE:
-	case NETDEV_GOING_DOWN:
-	case NETDEV_UNREGISTER:
-	case NETDEV_UNREGISTER_FINAL:
-	case NETDEV_RELEASE:
-	case NETDEV_JOIN:
-	case NETDEV_BONDING_INFO:
+	case NETDEV_REBOOT:
+	case NETDEV_CHANGEMTU:
+	case NETDEV_CHANGENAME:
+	case NETDEV_FEAT_CHANGE:
+	case NETDEV_BONDING_FAILOVER:
+	case NETDEV_NOTIFY_PEERS:
+	case NETDEV_CHANGEUPPER:
+	case NETDEV_RESEND_IGMP:
+	case NETDEV_PRECHANGEMTU:
+	case NETDEV_CHANGEINFODATA:
+	case NETDEV_PRECHANGEUPPER:
+	case NETDEV_CHANGELOWERSTATE:
+	case NETDEV_UDP_TUNNEL_PUSH_INFO:
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
+		rtmsg_ifinfo(RTM_NEWLINK, dev, 0, GFP_KERNEL);
 		break;
 	default:
-		rtmsg_ifinfo(RTM_NEWLINK, dev, 0, GFP_KERNEL);
 		break;
 	}
 	return NOTIFY_DONE;
-- 
2.7.4

Re: [PATCH net-next 1/2] rtnetlink: Convert rtnetlink_event to white list

[David Ahern]

On 3/31/17 8:27 PM, Vladislav Yasevich wrote:
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index 9c3947a..f48a60d 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -4116,22 +4116,23 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
>  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
>  
>  	switch (event) {
> -	case NETDEV_UP:
> -	case NETDEV_DOWN:
> -	case NETDEV_PRE_UP:
> -	case NETDEV_POST_INIT:
> -	case NETDEV_REGISTER:
> -	case NETDEV_CHANGE:
> -	case NETDEV_PRE_TYPE_CHANGE:
> -	case NETDEV_GOING_DOWN:
> -	case NETDEV_UNREGISTER:
> -	case NETDEV_UNREGISTER_FINAL:
> -	case NETDEV_RELEASE:
> -	case NETDEV_JOIN:
> -	case NETDEV_BONDING_INFO:
> +	case NETDEV_REBOOT:
> +	case NETDEV_CHANGEMTU:
> +	case NETDEV_CHANGENAME:
> +	case NETDEV_FEAT_CHANGE:
> +	case NETDEV_BONDING_FAILOVER:
> +	case NETDEV_NOTIFY_PEERS:
> +	case NETDEV_CHANGEUPPER:
> +	case NETDEV_RESEND_IGMP:
> +	case NETDEV_PRECHANGEMTU:
> +	case NETDEV_CHANGEINFODATA:
> +	case NETDEV_PRECHANGEUPPER:
> +	case NETDEV_CHANGELOWERSTATE:
> +	case NETDEV_UDP_TUNNEL_PUSH_INFO:
> +	case NETDEV_CHANGE_TX_QUEUE_LEN:

missing NETDEV_CHANGEADDR and NETDEV_POST_TYPE_CHANGE

since this patch is just flipping the list type, those should be added here.

[PATCH V2 net-next 2/2] rtnetlink: Add support for netdev event to link messages

[Vladislav Yasevich]

When netdev events happen, a rtnetlink_event() handler will send
messages for every event in it's white list.  These messages contain
current information about a particular device, but they do not include
the iformation about which event just happened.  The consumer of
the message has to try to infer this information.  In some cases
(ex: NETDEV_NOTIFY_PEERS), that is not possible.

This patch adds a new extension to RTM_NEWLINK message called IFLA_EVENT
that would have an encoding of the which event triggered this
message.  This would allow the the message consumer to easily determine
if it is interested in a particular event or not.

Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
---
 include/linux/rtnetlink.h    |  3 +-
 include/uapi/linux/if_link.h | 19 ++++++++++
 net/core/dev.c               |  2 +-
 net/core/rtnetlink.c         | 86 +++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 99 insertions(+), 11 deletions(-)

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 57e5484..0459018 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -18,7 +18,8 @@ extern int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst,
 
 void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change, gfp_t flags);
 struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
-				       unsigned change, gfp_t flags);
+				       unsigned change, unsigned long event,
+				       gfp_t flags);
 void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev,
 		       gfp_t flags);
 
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 320fc1e..8eaada5 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -157,6 +157,7 @@ enum {
 	IFLA_GSO_MAX_SIZE,
 	IFLA_PAD,
 	IFLA_XDP,
+	IFLA_EVENT,
 	__IFLA_MAX
 };
 
@@ -892,4 +893,22 @@ enum {
 
 #define IFLA_XDP_MAX (__IFLA_XDP_MAX - 1)
 
+enum {
+	IFLA_EVENT_UNSPEC,
+	IFLA_EVENT_REBOOT,
+	IFLA_EVENT_CHANGE_MTU,
+	IFLA_EVENT_CHANGE_NAME,
+	IFLA_EVENT_FEAT_CHANGE,
+	IFLA_EVENT_BONDING_FAILOVER,
+	IFLA_EVENT_NOTIFY_PEERS,
+	IFLA_EVENT_CHANGE_UPPER,
+	IFLA_EVENT_RESEND_IGMP,
+	IFLA_EVENT_PRE_CHANGE_MTU,
+	IFLA_EVENT_CHANGE_INFO_DATA,
+	IFLA_EVENT_PRE_CHANGE_UPPER,
+	IFLA_EVENT_CHANGE_LOWER_STATE,
+	IFLA_EVENT_UDP_TUNNEL_PUSH_INFO,
+	IFLA_EVENT_CHANGE_TX_QUEUE_LEN,
+};
+
 #endif /* _UAPI_LINUX_IF_LINK_H */
diff --git a/net/core/dev.c b/net/core/dev.c
index ef9fe60e..7efb417 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6840,7 +6840,7 @@ static void rollback_registered_many(struct list_head *head)
 
 		if (!dev->rtnl_link_ops ||
 		    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
-			skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U,
+			skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0,
 						     GFP_KERNEL);
 
 		/*
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f48a60d..956729c 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -944,6 +944,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */
 	       + nla_total_size(IFNAMSIZ) /* IFLA_PHYS_PORT_NAME */
 	       + rtnl_xdp_size(dev) /* IFLA_XDP */
+	       + nla_total_size(4)  /* IFLA_EVENT */
 	       + nla_total_size(1); /* IFLA_PROTO_DOWN */
 
 }
@@ -1276,9 +1277,64 @@ static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
 	return err;
 }
 
+static int rtnl_fill_link_event(struct sk_buff *skb, unsigned long event)
+{
+	u32 rtnl_event;
+
+	switch (event) {
+	case NETDEV_REBOOT:
+		rtnl_event = IFLA_EVENT_REBOOT;
+		break;
+	case NETDEV_CHANGEMTU:
+		rtnl_event = IFLA_EVENT_CHANGE_MTU;
+		break;
+	case NETDEV_CHANGENAME:
+		rtnl_event = IFLA_EVENT_CHANGE_NAME;
+		break;
+	case NETDEV_FEAT_CHANGE:
+		rtnl_event = IFLA_EVENT_FEAT_CHANGE;
+		break;
+	case NETDEV_BONDING_FAILOVER:
+		rtnl_event = IFLA_EVENT_BONDING_FAILOVER;
+		break;
+	case NETDEV_NOTIFY_PEERS:
+		rtnl_event = IFLA_EVENT_NOTIFY_PEERS;
+		break;
+	case NETDEV_CHANGEUPPER:
+		rtnl_event = IFLA_EVENT_CHANGE_UPPER;
+		break;
+	case NETDEV_RESEND_IGMP:
+		rtnl_event = IFLA_EVENT_RESEND_IGMP;
+		break;
+	case NETDEV_PRECHANGEMTU:
+		rtnl_event = IFLA_EVENT_PRE_CHANGE_MTU;
+		break;
+	case NETDEV_CHANGEINFODATA:
+		rtnl_event = IFLA_EVENT_CHANGE_INFO_DATA;
+		break;
+	case NETDEV_PRECHANGEUPPER:
+		rtnl_event = IFLA_EVENT_PRE_CHANGE_UPPER;
+		break;
+	case NETDEV_CHANGELOWERSTATE:
+		rtnl_event = IFLA_EVENT_CHANGE_LOWER_STATE;
+		break;
+	case NETDEV_UDP_TUNNEL_PUSH_INFO:
+		rtnl_event = IFLA_EVENT_UDP_TUNNEL_PUSH_INFO;
+		break;
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
+		rtnl_event = IFLA_EVENT_CHANGE_TX_QUEUE_LEN;
+		break;
+	default:
+		return 0;
+	}
+
+	return nla_put_u32(skb, IFLA_EVENT, rtnl_event);
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 			    int type, u32 pid, u32 seq, u32 change,
-			    unsigned int flags, u32 ext_filter_mask)
+			    unsigned int flags, u32 ext_filter_mask,
+			    unsigned long event)
 {
 	struct ifinfomsg *ifm;
 	struct nlmsghdr *nlh;
@@ -1327,6 +1383,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	    nla_put_u8(skb, IFLA_PROTO_DOWN, dev->proto_down))
 		goto nla_put_failure;
 
+	if (rtnl_fill_link_event(skb, event))
+		goto nla_put_failure;
+
 	if (rtnl_fill_link_ifmap(skb, dev))
 		goto nla_put_failure;
 
@@ -1461,6 +1520,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_LINK_NETNSID]	= { .type = NLA_S32 },
 	[IFLA_PROTO_DOWN]	= { .type = NLA_U8 },
 	[IFLA_XDP]		= { .type = NLA_NESTED },
+	[IFLA_EVENT]		= { .type = NLA_U32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -1619,7 +1679,7 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 					       NETLINK_CB(cb->skb).portid,
 					       cb->nlh->nlmsg_seq, 0,
 					       flags,
-					       ext_filter_mask);
+					       ext_filter_mask, 0);
 			/* If we ran out of room on the first message,
 			 * we're in trouble
 			 */
@@ -2710,7 +2770,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh)
 		return -ENOBUFS;
 
 	err = rtnl_fill_ifinfo(nskb, dev, RTM_NEWLINK, NETLINK_CB(skb).portid,
-			       nlh->nlmsg_seq, 0, 0, ext_filter_mask);
+			       nlh->nlmsg_seq, 0, 0, ext_filter_mask, 0);
 	if (err < 0) {
 		/* -EMSGSIZE implies BUG in if_nlmsg_size */
 		WARN_ON(err == -EMSGSIZE);
@@ -2782,7 +2842,8 @@ static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
 }
 
 struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
-				       unsigned int change, gfp_t flags)
+				       unsigned int change,
+				       unsigned long event, gfp_t flags)
 {
 	struct net *net = dev_net(dev);
 	struct sk_buff *skb;
@@ -2793,7 +2854,7 @@ struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
 	if (skb == NULL)
 		goto errout;
 
-	err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0, 0);
+	err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0, 0, event);
 	if (err < 0) {
 		/* -EMSGSIZE implies BUG in if_nlmsg_size() */
 		WARN_ON(err == -EMSGSIZE);
@@ -2814,18 +2875,25 @@ void rtmsg_ifinfo_send(struct sk_buff *skb, struct net_device *dev, gfp_t flags)
 	rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, flags);
 }
 
-void rtmsg_ifinfo(int type, struct net_device *dev, unsigned int change,
-		  gfp_t flags)
+static void rtmsg_ifinfo_event(int type, struct net_device *dev,
+			       unsigned int change, unsigned long event,
+			       gfp_t flags)
 {
 	struct sk_buff *skb;
 
 	if (dev->reg_state != NETREG_REGISTERED)
 		return;
 
-	skb = rtmsg_ifinfo_build_skb(type, dev, change, flags);
+	skb = rtmsg_ifinfo_build_skb(type, dev, change, event, flags);
 	if (skb)
 		rtmsg_ifinfo_send(skb, dev, flags);
 }
+
+void rtmsg_ifinfo(int type, struct net_device *dev, unsigned int change,
+		  gfp_t flags)
+{
+	rtmsg_ifinfo_event(type, dev, change, 0, flags);
+}
 EXPORT_SYMBOL(rtmsg_ifinfo);
 
 static int nlmsg_populate_fdb_fill(struct sk_buff *skb,
@@ -4130,7 +4198,7 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
 	case NETDEV_CHANGELOWERSTATE:
 	case NETDEV_UDP_TUNNEL_PUSH_INFO:
 	case NETDEV_CHANGE_TX_QUEUE_LEN:
-		rtmsg_ifinfo(RTM_NEWLINK, dev, 0, GFP_KERNEL);
+		rtmsg_ifinfo_event(RTM_NEWLINK, dev, 0, event, GFP_KERNEL);
 		break;
 	default:
 		break;
-- 
2.7.4