Subject: Re: [PATCH] bonding: Allow tun-interfaces as slaves

From: Ding Tianhong <[email-masked]>
Date: Wed, 10 Aug 2016 17:27:56 +0800

On 2016/8/10 7:51, Jay Vosburgh wrote:
> Jörn Engel <[email-masked]> wrote:
> 
>> On Tue, Aug 09, 2016 at 12:06:36PM -0700, David Miller wrote:
>>>> On Tue, Aug 09, 2016 at 09:28:45PM +0800, Ding Tianhong wrote:
>>>>
>>>> Simply not checking errors when setting the mac address solves the
>>>> problem for me.  No new features needed.
>>>
>>> But it only works in certain modes.
>>>
>>> So the best we can do is enforce the MAC address setting in the
>>> modes that absolutely require it.  We cannot ignore the MAC
>>> address setting unilaterally.
>>
>> Something like this?
>>
>> [PATCH] bonding: Allow tun-interfaces as slaves in balance-rr mode
>>
>> Up until 00503b6f702e (part of 3.14-rc1), the bonding driver could be
>> used to enslave tun-interfaces.  00503b6f702e broke that behaviour,
>> afaics as an unintended side-effect.
>>
>> For the purpose of bond-over-tun in balance-rr mode, simply ignoring the
>> error from dev_set_mac_address() is good enough.
>>
>> Signed-off-by: Joern Engel <[email-masked]>
>> ---
>> drivers/net/bonding/bond_main.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>> index 1f276fa30ba6..2f686bfe4304 100644
>> --- a/drivers/net/bonding/bond_main.c
>> +++ b/drivers/net/bonding/bond_main.c
>> @@ -1490,7 +1490,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>> 		memcpy(addr.sa_data, bond_dev->dev_addr, bond_dev->addr_len);
>> 		addr.sa_family = slave_dev->type;
>> 		res = dev_set_mac_address(slave_dev, &addr);
>> -		if (res) {
>> +		/* round-robin mode works fine without a mac address */
>> +		if (res && BOND_MODE(bond) != BOND_MODE_ROUNDROBIN) {
> 
> 	This will cause balance-rr to add the slave to the bond if any
> device's dev_set_mac_address call fails.
> 
> 	If a bond of regular Ethernet devices is connected to a static
> link aggregation (Etherchannel channel group), a set_mac failure would
> result in that slave having a different MAC address than the bond, which
> in turn would cause traffic inbound from the switch to that slave to be
> dropped (as the destination MAC would not pass the device MAC filters).
> 
> 	The failure check for the set_mac call serves a legitimate
> purpose, and I don't believe we should bypass it without making the
> bypass an option that is explicitly enabled for those special cases that
> need it.
> 
> 	E.g., something like the following (which I have not tested);
> this would also need documentation and iproute2 updates to go with it.
> This would be enabled with "fail_over_mac=keepmac".
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 1f276fa30ba6..d2283fc23b16 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -1483,7 +1483,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>  	ether_addr_copy(new_slave->perm_hwaddr, slave_dev->dev_addr);
>  
>  	if (!bond->params.fail_over_mac ||
> -	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
> +	    (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP &&
> +	     bond->params.fail_over_mac != BOND_FOM_KEEPMAC)) {
>  		/* Set slave to master's mac address.  The application already
>  		 * set the master's mac address to that of the first slave
>  		 */
> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index 577e57cad1dc..f9653fe4d622 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -125,6 +125,7 @@ static const struct bond_opt_value bond_fail_over_mac_tbl[] = {
>  	{ "none",   BOND_FOM_NONE,   BOND_VALFLAG_DEFAULT},
>  	{ "active", BOND_FOM_ACTIVE, 0},
>  	{ "follow", BOND_FOM_FOLLOW, 0},
> +	{ "keepmac", BOND_FOM_KEEPMAC, 0},
>  	{ NULL,     -1,              0},
>  };
>  
> diff --git a/include/net/bonding.h b/include/net/bonding.h
> index 6360c259da6d..ec3442b3aa83 100644
> --- a/include/net/bonding.h
> +++ b/include/net/bonding.h
> @@ -420,6 +420,7 @@ static inline bool bond_slave_can_tx(struct slave *slave)
>  #define BOND_FOM_NONE			0
>  #define BOND_FOM_ACTIVE			1
>  #define BOND_FOM_FOLLOW			2
> +#define BOND_FOM_KEEPMAC		3
>  
>  #define BOND_ARP_TARGETS_ANY		0
>  #define BOND_ARP_TARGETS_ALL		1
> 
> 
> 	-J
> 
Hi jorn:

Could you please test this patch? I build this patch base on Jay's suggestion and I think it could fix your problem.

---
 drivers/net/bonding/bond_main.c    | 24 +++++++++---------------
 drivers/net/bonding/bond_options.c |  3 ++-
 include/net/bonding.h              |  1 +
 3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 1f276fa..dd4a8eb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -174,9 +174,9 @@ MODULE_PARM_DESC(arp_validate, "validate src/dst of ARP probes; "
 module_param(arp_all_targets, charp, 0);
 MODULE_PARM_DESC(arp_all_targets, "fail on any/all arp targets timeout; 0 for any (default), 1 for all");
 module_param(fail_over_mac, charp, 0);
-MODULE_PARM_DESC(fail_over_mac, "For active-backup, do not set all slaves to "
-				"the same MAC; 0 for none (default), "
-				"1 for active, 2 for follow");
+MODULE_PARM_DESC(fail_over_mac, "Do not set all slaves to the same MAC; "
+				"0 for none (default), 1 for active, "
+				"2 for follow, 3 for keepmac");
 module_param(all_slaves_active, int, 0);
 MODULE_PARM_DESC(all_slaves_active, "Keep all frames received on an interface "
 				     "by setting active flag for all slaves; "
@@ -1482,8 +1482,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	 */
 	ether_addr_copy(new_slave->perm_hwaddr, slave_dev->dev_addr);
 
-	if (!bond->params.fail_over_mac ||
-	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
+	if (bond->params.fail_over_mac == BOND_FOM_NONE) {
 		/* Set slave to master's mac address.  The application already
 		 * set the master's mac address to that of the first slave
 		 */
@@ -1766,8 +1765,7 @@ err_close:
 
 err_restore_mac:
 	slave_dev->flags &= ~IFF_SLAVE;
-	if (!bond->params.fail_over_mac ||
-	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
+	if (bond->params.fail_over_mac == BOND_FOM_NONE) {
 		/* XXX TODO - fom follow mode needs to change master's
 		 * MAC if this slave's MAC is in use by the bond, or at
 		 * least print a warning.
@@ -1867,8 +1865,7 @@ static int __bond_release_one(struct net_device *bond_dev,
 
 	RCU_INIT_POINTER(bond->current_arp_slave, NULL);
 
-	if (!all && (!bond->params.fail_over_mac ||
-		     BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)) {
+	if (!all && bond->params.fail_over_mac == BOND_FOM_NONE) {
 		if (ether_addr_equal_64bits(bond_dev->dev_addr, slave->perm_hwaddr) &&
 		    bond_has_slaves(bond))
 			netdev_warn(bond_dev, "the permanent HWaddr of %s - %pM - is still in use by %s - set the HWaddr of %s to a different address to avoid conflicts\n",
@@ -1949,8 +1946,8 @@ static int __bond_release_one(struct net_device *bond_dev,
 	/* close slave before restoring its mac address */
 	dev_close(slave_dev);
 
-	if (bond->params.fail_over_mac != BOND_FOM_ACTIVE ||
-	    BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
+	if (bond->params.fail_over_mac == BOND_FOM_FOLLOW ||
+	    bond->params.fail_over_mac == BOND_FOM_NONE) {
 		/* restore original ("permanent") mac address */
 		ether_addr_copy(addr.sa_data, slave->perm_hwaddr);
 		addr.sa_family = slave_dev->type;
@@ -3634,8 +3631,7 @@ static int bond_set_mac_address(struct net_device *bond_dev, void *addr)
 	/* If fail_over_mac is enabled, do nothing and return success.
 	 * Returning an error causes ifenslave to fail.
 	 */
-	if (bond->params.fail_over_mac &&
-	    BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP)
+	if (bond->params.fail_over_mac)
 		return 0;
 
 	if (!is_valid_ether_addr(sa->sa_data))
@@ -4543,8 +4539,6 @@ static int bond_check_params(struct bond_params *params)
 			return -EINVAL;
 		}
 		fail_over_mac_value = valptr->value;
-		if (bond_mode != BOND_MODE_ACTIVEBACKUP)
-			pr_warn("Warning: fail_over_mac only affects active-backup mode\n");
 	} else {
 		fail_over_mac_value = BOND_FOM_NONE;
 	}
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 577e57c..9038be5 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -125,6 +125,7 @@ static const struct bond_opt_value bond_fail_over_mac_tbl[] = {
 	{ "none",   BOND_FOM_NONE,   BOND_VALFLAG_DEFAULT},
 	{ "active", BOND_FOM_ACTIVE, 0},
 	{ "follow", BOND_FOM_FOLLOW, 0},
+	{ "keepmac", BOND_FOM_KEEPMAC, 0},
 	{ NULL,     -1,              0},
 };
 
@@ -247,7 +248,7 @@ static const struct bond_option bond_opts[BOND_OPT_LAST] = {
 	[BOND_OPT_FAIL_OVER_MAC] = {
 		.id = BOND_OPT_FAIL_OVER_MAC,
 		.name = "fail_over_mac",
-		.desc = "For active-backup, do not set all slaves to the same MAC",
+		.desc = "Do not set all slaves to the same MAC",
 		.flags = BOND_OPTFLAG_NOSLAVES,
 		.values = bond_fail_over_mac_tbl,
 		.set = bond_option_fail_over_mac_set
diff --git a/include/net/bonding.h b/include/net/bonding.h
index 6360c25..ec3442b 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -420,6 +420,7 @@ static inline bool bond_slave_can_tx(struct slave *slave)
 #define BOND_FOM_NONE			0
 #define BOND_FOM_ACTIVE			1
 #define BOND_FOM_FOLLOW			2
+#define BOND_FOM_KEEPMAC		3
 
 #define BOND_ARP_TARGETS_ANY		0
 #define BOND_ARP_TARGETS_ALL		1
-- 
1.9.0

> ---
> 	-Jay Vosburgh, [email-masked]
> 
> .
>