Re: [PATCH] bonding: Avoid adding slave devices to inactive bonding

zhudi [off-list ref] wrote:

quoted

We need to refuse to add slave devices to the bonding which does
not set IFF_UP flag, otherwise some problems will be caused(such as
bond_set_carrier() will not sync carrier state to upper net device).
The ifenslave command can prevent such use case, but through the sysfs
interface, slave devices can still be added regardless of whether
the bonding is set with IFF_UP flag or not.

	What specifically happens in the carrier state issue you
mention?  Are there other specific issues?

yes, The following steps can cause problems:
	1)bond0 is down
	2) ip link add link bond0 name ipvlan type ipvlan mode l2
	3) echo +enp2s7 >/sys/class/net/bond0/bonding/slaves
	4) ip link set bond0 up

	After these steps, use ip link command, we found ipvlan has NO-CARRIER:
		ipvlan@bond0: <NO-CARRIER, BROADCAST,MULTICAST,UP,M-DOWN> mtu 1500 qdisc noqueue state>

	This is because,  bond_enslave()->bond_set_carrier()->netif_carrier_on()...->netdev_state_change() 
will not sync carrier state to ipvlan because the IFF_UP  flag is not set.

	As far as I can recall, adding interfaces to the bond while the
bond is down has worked for a very long time, so I'm concerned that
disabling that functionality will have impact on existing
configurations.

	Also, to the best of my knowledge, the currently packaged
ifenslave programs are scripts that utilize the sysfs interface.  I'm
unaware of current usage of the old C ifenslave program (removed from
the kernel source in 2013), although the kernel code should still
support it.

	We still use old ifenslave command and it  does only allow to add slave to bonding with up state, code is as follows:

	/* check if master is up; if not then fail any operation */
	if (!(master_flags.ifr_flags & IFF_UP)) {
		fprintf(stderr,
			"Illegal operation; the specified master interface "
			"'%s' is not up.\n",
			master_ifname);
		res = 1;
		goto out;
	}

	If so, the behavior of the new tool is inconsistent with that of the old tool.

	-J

quoted

So we introduce a new BOND_OPTFLAG_IFUP flag to avoid adding slave
devices to inactive bonding.

Signed-off-by: zhudi <redacted>
---
drivers/net/bonding/bond_options.c | 4 +++-
include/net/bond_options.h         | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bonding/bond_options.c

b/drivers/net/bonding/bond_options.c

quoted

index 0cf25de6f46d..6d2f44b3528d 100644

--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c

@@ -387,7 +387,7 @@ static const struct bond_option

bond_opts[BOND_OPT_LAST] = {

quoted

		.id = BOND_OPT_SLAVES,
		.name = "slaves",
		.desc = "Slave membership management",
-		.flags = BOND_OPTFLAG_RAWVAL,
+		.flags = BOND_OPTFLAG_RAWVAL | BOND_OPTFLAG_IFUP,
		.set = bond_option_slaves_set
	},
	[BOND_OPT_TLB_DYNAMIC_LB] = {

@@ -583,6 +583,8 @@ static int bond_opt_check_deps(struct bonding

*bond,

quoted

		return -ENOTEMPTY;
	if ((opt->flags & BOND_OPTFLAG_IFDOWN) && (bond->dev->flags &

IFF_UP))

quoted

		return -EBUSY;
+	if ((opt->flags & BOND_OPTFLAG_IFUP) && !(bond->dev->flags &

IFF_UP))

quoted

+		return -EPERM;

	return 0;
}

diff --git a/include/net/bond_options.h b/include/net/bond_options.h
index 9d382f2f0bc5..742f5cc81adf 100644
--- a/include/net/bond_options.h
+++ b/include/net/bond_options.h

@@ -15,11 +15,13 @@
 * BOND_OPTFLAG_NOSLAVES - check if the bond device is empty before

setting

quoted

 * BOND_OPTFLAG_IFDOWN - check if the bond device is down before

setting

quoted

 * BOND_OPTFLAG_RAWVAL - the option parses the value itself
+ * BOND_OPTFLAG_IFUP - check if the bond device is up before setting
 */
enum {
	BOND_OPTFLAG_NOSLAVES	= BIT(0),
	BOND_OPTFLAG_IFDOWN	= BIT(1),
-	BOND_OPTFLAG_RAWVAL	= BIT(2)
+	BOND_OPTFLAG_RAWVAL	= BIT(2),
+	BOND_OPTFLAG_IFUP	= BIT(3)
};

/* Value type flags:
--
2.27.0

---
	-Jay Vosburgh, jay.vosburgh@canonical.com