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

From: Ding Tianhong <[email-masked]>
Date: Thu, 11 Aug 2016 09:20:27 +0800

On 2016/8/11 1:41, Jay Vosburgh wrote:
> Ding Tianhong <[email-masked]> wrote:
> 
>> 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) {
> 
> 	I'm not sure we can make the change this way; I structured the
> test as:
> 
>  	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)) {
> 
> 	deliberately, because the current implementation permits setting
> f_o_m at any time, but it only takes effect in active-backup mode.  This
> is done to reduce ordering restrictions when setting up the bond,
> however, a user today could set f_o_m to "active" or "follow" in modes
> other than active-backup and it would have no effect, but your change
> would cause that identically configured bond to now behave differently.
> 

OK, it looks no need to restrict other mode(no active-backup mode) to work with active or follow policy,
no effect is enough.

> 	The test has to be structured such that f_o_m set to "active" or
> "follow" affects only active-backup mode, and f_o_m "keepmac" affects
> any mode.  We probably should move this into a helper, something like
> 
> bool bond_fom_enabled(bond)
> {
> 	if (bond->mode == BOND_MODE_ACTIVEBACKUP)
> 		return bond->params.fail_over_mac != BOND_FOM_NONE;
> 	else
> 		return bond->params.fail_over_mac == BOND_FOM_KEEPMAC;
> }
> 

fine.

Thanks.
Ding

> 	then the complicated test becomes
> 
> 	if (!bond_fom_enabled(bond)) {
> 		[ change the MAC address stuff ]
> 	}
> 
> 
> 	-J
> 
>> 		/* 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]
> 
> .
>