linux-kernel - Re: [BUG] port（belong to a lacp aggregate group）cannot be unselected while the connected port failed

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Date:   Fri, 10 Feb 2017 14:48:51 +0800
From:   zhou zhengwu <zhouzhengwu@...wei.com>
To:     Jay Vosburgh <fubar@...ibm.com>,
        Andy Gospodarek <andy@...yhouse.net>
CC:     <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] port（belong to a lacp aggregate group）cannot be unselected while the connected port failed

ad_rx_machine() -> __update_selected(), this funcition will check if any 
lacp parameter is different. If any change happened, related port will 
be unselected.

However, this function will not check the changing of port state, for 
example, whether partner port's port state is synchronization, which 
will make lacp state machine fail.


On 2017/2/9 17:19, zhou zhengwu wrote:
> Hi
>
> [1] Testing OS: SUSE 11SP3( kernel version 3.0.93)
>
> [2]Problem description:
>    ServerA [bond] ----------- [bond] ServerB
>    Two servers are connected with bonding interfaces LACP is enabled.
>    Firstly, it works well.
>    Then, one port (for example, port B) in serverB failed, it can send
> but not receive packets including the LACPDU however the port status is
> still UP.
>    Result:
>    In serverB, port B is unselected and traffic is sent through other
> aggregate port.
>    While In serverA, port A connecting with port B of serverB is still
> selected by LACP and traffic is still sent through it
>
> [3]Two question about the implementation of LACP RX machine:
>   1. Following judging condition marked with “*” is reasonable?
>
> static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
> {
>      …………………….
>                    case AD_RX_CURRENT:
>                             // detect loopback situation
>                             if
> (!MAC_ADDRESS_COMPARE(&(lacpdu->actor_system), &(port->actor_system))) {
>                                      // INFO_RECEIVED_LOOPBACK_FRAMES
>                                      pr_err("%s: An illegal loopback
> occurred on adapter (%s).\n"
>                                             "Check the configuration to
> verify that all adapters are connected to 802.3ad compliant switch
> ports\n",
>
> port->slave->dev->master->name, port->slave->dev->name);
>                                      return;
>                             }
>                             __update_selected(lacpdu, port);
>                             __update_ntt(lacpdu, port);
>                             __record_pdu(lacpdu, port);
>                             port->sm_rx_timer_counter =
> __ad_timer_to_ticks(AD_CURRENT_WHILE_TIMER,
> (u16)(port->actor_oper_port_state & AD_STATE_LACP_TIMEOUT));
>                             port->actor_oper_port_state &=
> ~AD_STATE_EXPIRED;
>                             // verify that if the aggregator is enabled,
> the port is enabled too.
>                             //(because if the link goes down for a short
> time, the 802.3ad will not
>                             // catch it, and the port will continue to
> be disabled)
>          *****                if (port->aggregator
>          *****           && port->aggregator->is_active
>          *****           && !__port_is_enabled(port))
>          *****                __enable_port(port); --------------------
> is the judging condition reasonable?
>                             break;
>        …………………….
> }
>
>    2. While lacp rx machine receive the lacpdu packets, whether the port
> should be selected or not should be done. Currently,if lacp rx machine
> is in AD_RX_CURRENT and if the partner's configuration is unchanged,
> port will still be selected. However, it is not reasonable in some
> conditions. For example, partner port failed which can send but not
> receive pkts. At the same time, the port still be UP.
>
> static void __update_selected(struct lacpdu *lacpdu, struct port *port)
> {
>     if (lacpdu && port) {
>         const struct port_params *partner = &port->partner_oper;
>
>         // check if any parameter is different
>         if (ntohs(lacpdu->actor_port) != partner->port_number ||
>             ntohs(lacpdu->actor_port_priority) != partner->port_priority ||
>             MAC_ADDRESS_COMPARE(&lacpdu->actor_system, &partner->system) ||
>             ntohs(lacpdu->actor_system_priority) !=
> partner->system_priority ||
>             ntohs(lacpdu->actor_key) != partner->key ||
>             (lacpdu->actor_state & AD_STATE_AGGREGATION) !=
> (partner->port_state & AD_STATE_AGGREGATION)) {
>             // update the state machine Selected variable
>             port->sm_vars &= ~AD_PORT_SELECTED;
>         }
>     }
> }