netdev - Re: [PATCH net] add support of IFF_XMIT_DST

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 for Android: free password hash cracker in your pocket

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

Message-Id: <1509635169.395392.1938.nullmailer@mnt-myt.yandex.net>
Date:   Thu, 02 Nov 2017 17:47:07 +0300
From:   Vadim Fedorenko <vfedorenko@...dex-team.ru>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Paweł Staszewski <pstaszewski@...are.pl>
Subject: Re: [PATCH net] add support of IFF_XMIT_DST_RELEASE bit in vlan

On Thu, 2017-11-02 at 07:33 -7000, Eric Dumazet wrote:
> On Thu, 2017-11-02 at 15:49 +0300, Vadim Fedorenko wrote:
>> Some time ago Eric Dumazet suggested a "hack the IFF_XMIT_DST_RELEASE
>> flag on the vlan netdev". But the last comment was "does not support
>> properly bonding/team.(If the real_dev->privflags IFF_XMIT_DST_RELEASE
>> bit changes, we want to update all the vlans at the same time )"
>> 
>> I've extended that patch to support changes of IFF_XMIT_DST_RELEASE in
>> bonding/team.
>> Both bonding and team call netdev_change_features() after recalculation
>> of features including priv_flags IFF_XMIT_DST_RELEASE bit. So the only
>> thing needed to support is to recheck this bit in
>> vlan_transfer_features().
>> 
>> Suggested-by: Eric Dumazet <eric.dumazet@...il.com>
>> Signed-off-by: Vadim Fedorenko <vfedorenko@...dex-team.ru>
>> ---
>>  net/8021q/vlan.c         | 3 +++
>>  net/8021q/vlan_netlink.c | 1 +
>>  2 files changed, 4 insertions(+)
>> 
>> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
>> index 9649579..510986c 100644
>> --- a/net/8021q/vlan.c
>> +++ b/net/8021q/vlan.c
>> @@ -328,6 +328,9 @@ static void vlan_transfer_features(struct net_device *dev,
>>  	vlandev->fcoe_ddp_xid = dev->fcoe_ddp_xid;
>>  #endif
>>  
>> +	vlandev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
>> +	vlandev->priv_flags |= (vlan->real_dev->priv_flags & IFF_XMIT_DST_RELEASE);
>> +
>>  	netdev_update_features(vlandev);
>>  }
>>  
>> diff --git a/net/8021q/vlan_netlink.c b/net/8021q/vlan_netlink.c
>> index 5e831de..9472de8 100644
>> --- a/net/8021q/vlan_netlink.c
>> +++ b/net/8021q/vlan_netlink.c
>> @@ -143,6 +143,7 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
>>  	vlan->vlan_proto = proto;
>>  	vlan->vlan_id	 = nla_get_u16(data[IFLA_VLAN_ID]);
>>  	vlan->real_dev	 = real_dev;
>> +	dev->priv_flags |= (real_dev->priv_flags & IFF_XMIT_DST_RELEASE);
>>  	vlan->flags	 = VLAN_FLAG_REORDER_HDR;
>>  
>>  	err = vlan_check_real_dev(real_dev, vlan->vlan_proto, vlan->vlan_id);
>
> What happens if a bonding is composed of two slaves, with different
> IFF_XMIT_DST_RELEASE settings ?

According to bond_compute_features() IFF_XMIT_DST_RELEASE flag is cleared from priv_flags
in such case, so it is cleared in vlan_transfer_features() and vlan device works as before
the patch.
The same code exists in team netdev.