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    Subject[PATCH 4.14 25/34] bonding: fix PACKET_ORIGDEV regression
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Michal Soltys <soltys@ziu.info>

    [ Upstream commit 3c963a3306eada999be5ebf4f293dfa3d3945487 ]

    This patch fixes a subtle PACKET_ORIGDEV regression which was a side
    effect of fixes introduced by:

    6a9e461f6fe4 bonding: pass link-local packets to bonding master also.

    ... to:

    b89f04c61efe bonding: deliver link-local packets with skb->dev set to link that packets arrived on

    While 6a9e461f6fe4 restored pre-b89f04c61efe presence of link-local
    packets on bonding masters (which is required e.g. by linux bridges
    participating in spanning tree or needed for lab-like setups created
    with group_fwd_mask) it also caused the originating device
    information to be lost due to cloning.

    Maciej Żenczykowski proposed another solution that doesn't require
    packet cloning and retains original device information - instead of
    returning RX_HANDLER_PASS for all link-local packets it's now limited
    only to packets from inactive slaves.

    At the same time, packets passed to bonding masters retain correct
    information about the originating device and PACKET_ORIGDEV can be used
    to determine it.

    This elegantly solves all issues so far:

    - link-local packets that were removed from bonding masters
    - LLDP daemons being forced to explicitly bind to slave interfaces
    - PACKET_ORIGDEV having no effect on bond interfaces

    Fixes: 6a9e461f6fe4 (bonding: pass link-local packets to bonding master also.)
    Reported-by: Vincent Bernat <vincent@bernat.ch>
    Signed-off-by: Michal Soltys <soltys@ziu.info>
    Signed-off-by: Maciej Żenczykowski <maze@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/net/bonding/bond_main.c | 35 ++++++++++++++---------------------
    1 file changed, 14 insertions(+), 21 deletions(-)

    --- a/drivers/net/bonding/bond_main.c
    +++ b/drivers/net/bonding/bond_main.c
    @@ -1177,29 +1177,22 @@ static rx_handler_result_t bond_handle_f
    }
    }

    - /* Link-local multicast packets should be passed to the
    - * stack on the link they arrive as well as pass them to the
    - * bond-master device. These packets are mostly usable when
    - * stack receives it with the link on which they arrive
    - * (e.g. LLDP) they also must be available on master. Some of
    - * the use cases include (but are not limited to): LLDP agents
    - * that must be able to operate both on enslaved interfaces as
    - * well as on bonds themselves; linux bridges that must be able
    - * to process/pass BPDUs from attached bonds when any kind of
    - * STP version is enabled on the network.
    + /*
    + * For packets determined by bond_should_deliver_exact_match() call to
    + * be suppressed we want to make an exception for link-local packets.
    + * This is necessary for e.g. LLDP daemons to be able to monitor
    + * inactive slave links without being forced to bind to them
    + * explicitly.
    + *
    + * At the same time, packets that are passed to the bonding master
    + * (including link-local ones) can have their originating interface
    + * determined via PACKET_ORIGDEV socket option.
    */
    - if (is_link_local_ether_addr(eth_hdr(skb)->h_dest)) {
    - struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
    -
    - if (nskb) {
    - nskb->dev = bond->dev;
    - nskb->queue_mapping = 0;
    - netif_rx(nskb);
    - }
    - return RX_HANDLER_PASS;
    - }
    - if (bond_should_deliver_exact_match(skb, slave, bond))
    + if (bond_should_deliver_exact_match(skb, slave, bond)) {
    + if (is_link_local_ether_addr(eth_hdr(skb)->h_dest))
    + return RX_HANDLER_PASS;
    return RX_HANDLER_EXACT;
    + }

    skb->dev = bond->dev;


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