4.20-stable review patch. If anyone has any objections, please let me know.
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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 @@ -1172,29 +1172,22 @@ 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;