netdev - [PATCH] Documentation: bring operstate documentation up-to-date

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190207161432.GA6060@Mindship-05.localdomain>
Date:   Thu, 7 Feb 2019 17:14:32 +0100
From:   Jouke Witteveen <j.witteveen@...il.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: [PATCH] Documentation: bring operstate documentation up-to-date

Netlink has moved from bitmasks to group numbers long ago.

Signed-off-by: Jouke Witteveen <j.witteveen@...il.com>
---
This has been salvaged from my earlier proposal to send uevents on link state
changes. Can I get you to reconsider that proposal? A more pervasive version of
the same idea was accepted in 2008 [1] but oddly enough never applied [2].
In the world of today, sending uevents would play very nicely with udev.

[1] http://patchwork.ozlabs.org/patch/10134/
[2] https://www.spinics.net/lists/netdev/thrd522.html#81497


 Documentation/networking/operstates.txt | 14 ++++++++------
 net/sched/sch_generic.c                 |  2 +-
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/Documentation/networking/operstates.txt b/Documentation/networking/operstates.txt
index 355c6d8ef8ad..b203d1334822 100644
--- a/Documentation/networking/operstates.txt
+++ b/Documentation/networking/operstates.txt
@@ -22,8 +22,9 @@ and changeable from userspace under certain rules.
 2. Querying from userspace
 
 Both admin and operational state can be queried via the netlink
-operation RTM_GETLINK. It is also possible to subscribe to RTMGRP_LINK
-to be notified of updates. This is important for setting from userspace.
+operation RTM_GETLINK. It is also possible to subscribe to RTNLGRP_LINK
+to be notified of updates while the interface is admin up. This is
+important for setting from userspace.
 
 These values contain interface state:
 
@@ -101,8 +102,9 @@ because some driver controlled protocol establishment has to
 complete. Corresponding functions are netif_dormant_on() to set the
 flag, netif_dormant_off() to clear it and netif_dormant() to query.
 
-On device allocation, networking core sets the flags equivalent to
-netif_carrier_ok() and !netif_dormant().
+On device allocation, both flags __LINK_STATE_NOCARRIER and
+__LINK_STATE_DORMANT are cleared, so the effective state is equivalent
+to netif_carrier_ok() and !netif_dormant().
 
 
 Whenever the driver CHANGES one of these flags, a workqueue event is
@@ -133,11 +135,11 @@ netif_carrier_ok() && !netif_dormant() is set by the
 driver. Afterwards, the userspace application can set IFLA_OPERSTATE
 to IF_OPER_DORMANT or IF_OPER_UP as long as the driver does not set
 netif_carrier_off() or netif_dormant_on(). Changes made by userspace
-are multicasted on the netlink group RTMGRP_LINK.
+are multicasted on the netlink group RTNLGRP_LINK.
 
 So basically a 802.1X supplicant interacts with the kernel like this:
 
--subscribe to RTMGRP_LINK
+-subscribe to RTNLGRP_LINK
 -set IFLA_LINKMODE to 1 via RTM_SETLINK
 -query RTM_GETLINK once to get initial state
 -if initial flags are not (IFF_LOWER_UP && !IFF_DORMANT), wait until
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 66ba2ce2320f..968a85fe4d4a 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -500,7 +500,7 @@ static void dev_watchdog_down(struct net_device *dev)
  *	netif_carrier_on - set carrier
  *	@dev: network device
  *
- * Device has detected that carrier.
+ * Device has detected acquisition of carrier.
  */
 void netif_carrier_on(struct net_device *dev)
 {
-- 
2.20.1