eth_slow.c

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/*
 * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdlib.h>
#include <string.h>
#include <byteswap.h>
#include <errno.h>
#include <ipxe/timer.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>
#include <ipxe/if_ether.h>
#include <ipxe/ethernet.h>
#include <ipxe/eth_slow.h>

/** @file
 *
 * Ethernet slow protocols
 *
 * We implement a very simple passive LACP entity, that pretends that
 * each port is the only port on an individual system.  We avoid the
 * need for timeout logic (and retaining local state about our
 * partner) by requesting the same timeout period (1s or 30s) as our
 * partner requests, and then simply responding to every packet the
 * partner sends us.
 */

struct net_protocol eth_slow_protocol __net_protocol;

/** Slow protocols multicast address */
static const uint8_t eth_slow_address[ETH_ALEN] =
        { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x02 };

/**
 * Name LACP TLV type
 *
 * @v type              LACP TLV type
 * @ret name            Name of LACP TLV type
 */
static inline __attribute__ (( always_inline )) const char *
eth_slow_lacp_tlv_name ( uint8_t type ) {
        switch ( type ) {
        case ETH_SLOW_TLV_TERMINATOR:           return "terminator";
        case ETH_SLOW_TLV_LACP_ACTOR:           return "actor";
        case ETH_SLOW_TLV_LACP_PARTNER:         return "partner";
        case ETH_SLOW_TLV_LACP_COLLECTOR:       return "collector";
        default:                                return "<invalid>";
        }
}

/**
 * Name marker TLV type
 *
 * @v type              Marker TLV type
 * @ret name            Name of marker TLV type
 */
static inline __attribute__ (( always_inline )) const char *
eth_slow_marker_tlv_name ( uint8_t type ) {
        switch ( type ) {
        case ETH_SLOW_TLV_TERMINATOR:           return "terminator";
        case ETH_SLOW_TLV_MARKER_REQUEST:       return "request";
        case ETH_SLOW_TLV_MARKER_RESPONSE:      return "response";
        default:                                return "<invalid>";
        }
}

/**
 * Name LACP state
 *
 * @v state             LACP state
 * @ret name            LACP state name
 */
static const char * eth_slow_lacp_state_name ( uint8_t state ) {
        static char state_chars[] = "AFGSCDLX";
        unsigned int i;

        for ( i = 0 ; i < 8 ; i++ ) {
                state_chars[i] |= 0x20;
                if ( state & ( 1 << i ) )
                        state_chars[i] &= ~0x20;
        }
        return state_chars;
}

/**
 * Dump LACP packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @v label             "RX" or "TX"
 */
static void eth_slow_lacp_dump ( struct io_buffer *iobuf,
                                 struct net_device *netdev,
                                 const char *label ) {
        union eth_slow_packet *eth_slow = iobuf->data;
        struct eth_slow_lacp *lacp = &eth_slow->lacp;

        DBGC ( netdev,
               "SLOW %s %s LACP actor (%04x,%s,%04x,%02x,%04x) [%s]\n",
               netdev->name, label, ntohs ( lacp->actor.system_priority ),
               eth_ntoa ( lacp->actor.system ),
               ntohs ( lacp->actor.key ),
               ntohs ( lacp->actor.port_priority ),
               ntohs ( lacp->actor.port ),
               eth_slow_lacp_state_name ( lacp->actor.state ) );
        DBGC ( netdev,
               "SLOW %s %s LACP partner (%04x,%s,%04x,%02x,%04x) [%s]\n",
               netdev->name, label, ntohs ( lacp->partner.system_priority ),
               eth_ntoa ( lacp->partner.system ),
               ntohs ( lacp->partner.key ),
               ntohs ( lacp->partner.port_priority ),
               ntohs ( lacp->partner.port ),
               eth_slow_lacp_state_name ( lacp->partner.state ) );
        DBGC ( netdev, "SLOW %s %s LACP collector %04x (%d us)\n",
               netdev->name, label, ntohs ( lacp->collector.max_delay ),
               ( ntohs ( lacp->collector.max_delay ) * 10 ) );
        DBGC2_HDA ( netdev, 0, iobuf->data, iob_len ( iobuf ) );
}

/**
 * Process incoming LACP packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int eth_slow_lacp_rx ( struct io_buffer *iobuf,
                              struct net_device *netdev ) {
        union eth_slow_packet *eth_slow = iobuf->data;
        struct eth_slow_lacp *lacp = &eth_slow->lacp;
        unsigned int interval;

        eth_slow_lacp_dump ( iobuf, netdev, "RX" );

        /* Check for looped-back packets */
        if ( memcmp ( lacp->actor.system, netdev->ll_addr,
                      sizeof ( lacp->actor.system ) ) == 0 ) {
                DBGC ( netdev, "SLOW %s RX loopback detected\n",
                       netdev->name );
                return -ELOOP;
        }

        /* If partner is not in sync, collecting, and distributing,
         * then block the link until after the next expected LACP
         * packet.
         */
        if ( ~lacp->actor.state & ( LACP_STATE_IN_SYNC |
                                    LACP_STATE_COLLECTING |
                                    LACP_STATE_DISTRIBUTING ) ) {
                DBGC ( netdev, "SLOW %s LACP partner is down\n", netdev->name );
                interval = ( ( lacp->actor.state & LACP_STATE_FAST ) ?
                             ( ( LACP_INTERVAL_FAST + 1 ) * TICKS_PER_SEC ) :
                             ( ( LACP_INTERVAL_SLOW + 1 ) * TICKS_PER_SEC ) );
                netdev_link_block ( netdev, interval );
        } else {
                if ( netdev_link_blocked ( netdev ) ) {
                        DBGC ( netdev, "SLOW %s LACP partner is up\n",
                               netdev->name );
                }
                netdev_link_unblock ( netdev );
        }

        /* Build response */
        memset ( lacp->reserved, 0, sizeof ( lacp->reserved ) );
        memset ( &lacp->terminator, 0, sizeof ( lacp->terminator ) );
        memset ( &lacp->collector, 0, sizeof ( lacp->collector ) );
        lacp->collector.tlv.type = ETH_SLOW_TLV_LACP_COLLECTOR;
        lacp->collector.tlv.length = ETH_SLOW_TLV_LACP_COLLECTOR_LEN;
        memcpy ( &lacp->partner, &lacp->actor, sizeof ( lacp->partner ) );
        lacp->partner.tlv.type = ETH_SLOW_TLV_LACP_PARTNER;
        lacp->partner.tlv.length = ETH_SLOW_TLV_LACP_PARTNER_LEN;
        memset ( &lacp->partner.reserved, 0,
                 sizeof ( lacp->partner.reserved ) );
        memset ( &lacp->actor, 0, sizeof ( lacp->actor ) );
        lacp->actor.tlv.type = ETH_SLOW_TLV_LACP_ACTOR;
        lacp->actor.tlv.length = ETH_SLOW_TLV_LACP_ACTOR_LEN;
        lacp->actor.system_priority = htons ( LACP_SYSTEM_PRIORITY_MAX );
        memcpy ( lacp->actor.system, netdev->ll_addr,
                 sizeof ( lacp->actor.system ) );
        lacp->actor.key = htons ( 1 );
        lacp->actor.port_priority = htons ( LACP_PORT_PRIORITY_MAX );
        lacp->actor.port = htons ( 1 );
        lacp->actor.state = ( LACP_STATE_AGGREGATABLE |
                              LACP_STATE_IN_SYNC |
                              LACP_STATE_COLLECTING |
                              LACP_STATE_DISTRIBUTING |
                              ( lacp->partner.state & LACP_STATE_FAST ) );
        lacp->header.version = ETH_SLOW_LACP_VERSION;

        /* Send response */
        eth_slow_lacp_dump ( iobuf, netdev, "TX" );
        return net_tx ( iobuf, netdev, &eth_slow_protocol, eth_slow_address,
                        netdev->ll_addr );
}

/**
 * Dump marker packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @v label             "RX" or "TX"
 */
static void eth_slow_marker_dump ( struct io_buffer *iobuf,
                                   struct net_device *netdev,
                                   const char *label ) {
        union eth_slow_packet *eth_slow = iobuf->data;
        struct eth_slow_marker *marker = &eth_slow->marker;

        DBGC ( netdev, "SLOW %s %s marker %s port %04x system %s xact %08x\n",
               netdev->name, label,
               eth_slow_marker_tlv_name ( marker->marker.tlv.type ),
               ntohs ( marker->marker.port ),
               eth_ntoa ( marker->marker.system ),
               ntohl ( marker->marker.xact ) );
        DBGC2_HDA ( netdev, 0, iobuf->data, iob_len ( iobuf ) );
}

/**
 * Process incoming marker packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int eth_slow_marker_rx ( struct io_buffer *iobuf,
                                struct net_device *netdev ) {
        union eth_slow_packet *eth_slow = iobuf->data;
        struct eth_slow_marker *marker = &eth_slow->marker;

        eth_slow_marker_dump ( iobuf, netdev, "RX" );

        if ( marker->marker.tlv.type == ETH_SLOW_TLV_MARKER_REQUEST ) {
                /* Send marker response */
                marker->marker.tlv.type = ETH_SLOW_TLV_MARKER_RESPONSE;
                eth_slow_marker_dump ( iobuf, netdev, "TX" );
                return net_tx ( iobuf, netdev, &eth_slow_protocol,
                                eth_slow_address, netdev->ll_addr );
        } else {
                /* Discard all other marker packets */
                free_iob ( iobuf );
                return -EINVAL;
        }
}

/**
 * Process incoming slow packet
 *
 * @v iobuf             I/O buffer
 * @v netdev            Network device
 * @v ll_dest           Link-layer destination address
 * @v ll_source         Link-layer source address
 * @v flags             Packet flags
 * @ret rc              Return status code
 */
static int eth_slow_rx ( struct io_buffer *iobuf,
                         struct net_device *netdev,
                         const void *ll_dest __unused,
                         const void *ll_source __unused,
                         unsigned int flags __unused ) {
        union eth_slow_packet *eth_slow = iobuf->data;

        /* Sanity checks */
        if ( iob_len ( iobuf ) < sizeof ( *eth_slow ) ) {
                free_iob ( iobuf );
                return -EINVAL;
        }

        /* Strip any trailing padding */
        iob_unput ( iobuf, ( sizeof ( *eth_slow ) - iob_len ( iobuf ) ) );

        /* Handle according to subtype */
        switch ( eth_slow->header.subtype ) {
        case ETH_SLOW_SUBTYPE_LACP:
                return eth_slow_lacp_rx ( iobuf, netdev );
        case ETH_SLOW_SUBTYPE_MARKER:
                return eth_slow_marker_rx ( iobuf, netdev );
        default:
                DBGC ( netdev, "SLOW %s RX unknown subtype %02x\n",
                       netdev->name, eth_slow->header.subtype );
                free_iob ( iobuf );
                return -EINVAL;
        }
}

/** Slow protocol */
struct net_protocol eth_slow_protocol __net_protocol = {
        .name = "Slow",
        .net_proto = htons ( ETH_P_SLOW ),
        .rx = eth_slow_rx,
};