ipoib.c

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/*
 * Copyright (C) 2007 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 <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <byteswap.h>
#include <errno.h>
#include <ipxe/errortab.h>
#include <ipxe/malloc.h>
#include <ipxe/if_arp.h>
#include <ipxe/arp.h>
#include <ipxe/if_ether.h>
#include <ipxe/ethernet.h>
#include <ipxe/ip.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>
#include <ipxe/infiniband.h>
#include <ipxe/ib_pathrec.h>
#include <ipxe/ib_mcast.h>
#include <ipxe/retry.h>
#include <ipxe/ipoib.h>

/** @file
 *
 * IP over Infiniband
 */

/* Disambiguate the various error causes */
#define ENXIO_ARP_REPLY __einfo_error ( EINFO_ENXIO_ARP_REPLY )
#define EINFO_ENXIO_ARP_REPLY                                           \
        __einfo_uniqify ( EINFO_ENXIO, 0x01,                            \
                          "Missing REMAC for ARP reply target address" )
#define ENXIO_NON_IPV4 __einfo_error ( EINFO_ENXIO_NON_IPV4 )
#define EINFO_ENXIO_NON_IPV4                                            \
        __einfo_uniqify ( EINFO_ENXIO, 0x02,                            \
                          "Missing REMAC for non-IPv4 packet" )
#define ENXIO_ARP_SENT __einfo_error ( EINFO_ENXIO_ARP_SENT )
#define EINFO_ENXIO_ARP_SENT                                            \
        __einfo_uniqify ( EINFO_ENXIO, 0x03,                            \
                          "Missing REMAC for IPv4 packet (ARP sent)" )

/** Number of IPoIB send work queue entries */
#define IPOIB_NUM_SEND_WQES 8

/** Number of IPoIB receive work queue entries */
#define IPOIB_NUM_RECV_WQES 4

/** Number of IPoIB completion entries */
#define IPOIB_NUM_CQES 16

/** An IPoIB broadcast address */
struct ipoib_broadcast {
        /** MAC address */
        struct ipoib_mac mac;
        /** Address vector */
        struct ib_address_vector av;
        /** Multicast group membership */
        struct ib_mc_membership membership;
};

/** An IPoIB device */
struct ipoib_device {
        /** Network device */
        struct net_device *netdev;
        /** Underlying Infiniband device */
        struct ib_device *ibdev;
        /** List of IPoIB devices */
        struct list_head list;
        /** Completion queue */
        struct ib_completion_queue *cq;
        /** Queue pair */
        struct ib_queue_pair *qp;
        /** Local MAC */
        struct ipoib_mac mac;
        /** Broadcast address */
        struct ipoib_broadcast broadcast;
        /** REMAC cache */
        struct list_head peers;
};

/** Broadcast IPoIB address */
static struct ipoib_mac ipoib_broadcast = {
        .flags__qpn = htonl ( IB_QPN_BROADCAST ),
        .gid.bytes = { 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00,
                       0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff },
};

/** Link status for "broadcast join in progress" */
#define EINPROGRESS_JOINING __einfo_error ( EINFO_EINPROGRESS_JOINING )
#define EINFO_EINPROGRESS_JOINING __einfo_uniqify \
        ( EINFO_EINPROGRESS, 0x01, "Joining" )

/** Human-readable message for the link status */
struct errortab ipoib_errors[] __errortab = {
        __einfo_errortab ( EINFO_EINPROGRESS_JOINING ),
};

/** List of all IPoIB devices */
static LIST_HEAD ( ipoib_devices );

static struct net_device_operations ipoib_operations;

/****************************************************************************
 *
 * IPoIB REMAC cache
 *
 ****************************************************************************
 */

/** An IPoIB REMAC cache entry */
struct ipoib_peer {
        /** List of REMAC cache entries */
        struct list_head list;
        /** Remote Ethermet MAC */
        struct ipoib_remac remac;
        /** MAC address */
        struct ipoib_mac mac;
};

/**
 * Find IPoIB MAC from REMAC
 *
 * @v ipoib             IPoIB device
 * @v remac             Remote Ethernet MAC
 * @ret mac             IPoIB MAC (or NULL if not found)
 */
static struct ipoib_mac * ipoib_find_remac ( struct ipoib_device *ipoib,
                                             const struct ipoib_remac *remac ) {
        struct ipoib_peer *peer;

        /* Check for broadcast or multicast REMAC.  We transmit
         * multicasts as broadcasts for simplicity.
         */
        if ( is_multicast_ether_addr ( remac ) )
                return &ipoib->broadcast.mac;

        /* Try to find via REMAC cache */
        list_for_each_entry ( peer, &ipoib->peers, list ) {
                if ( memcmp ( remac, &peer->remac,
                              sizeof ( peer->remac ) ) == 0 ) {
                        /* Move peer to start of list */
                        list_del ( &peer->list );
                        list_add ( &peer->list, &ipoib->peers );
                        return &peer->mac;
                }
        }

        DBGC ( ipoib, "IPoIB %p unknown REMAC %s\n",
               ipoib, eth_ntoa ( remac ) );
        return NULL;
}

/**
 * Add IPoIB MAC to REMAC cache
 *
 * @v ipoib             IPoIB device
 * @v remac             Remote Ethernet MAC
 * @v mac               IPoIB MAC
 * @ret rc              Return status code
 */
static int ipoib_map_remac ( struct ipoib_device *ipoib,
                             const struct ipoib_remac *remac,
                             const struct ipoib_mac *mac ) {
        struct ipoib_peer *peer;

        /* Check for existing entry in REMAC cache */
        list_for_each_entry ( peer, &ipoib->peers, list ) {
                if ( memcmp ( remac, &peer->remac,
                              sizeof ( peer->remac ) ) == 0 ) {
                        /* Move peer to start of list */
                        list_del ( &peer->list );
                        list_add ( &peer->list, &ipoib->peers );
                        /* Update MAC */
                        memcpy ( &peer->mac, mac, sizeof ( peer->mac ) );
                        return 0;
                }
        }

        /* Create new entry */
        peer = malloc ( sizeof ( *peer ) );
        if ( ! peer )
                return -ENOMEM;
        memcpy ( &peer->remac, remac, sizeof ( peer->remac ) );
        memcpy ( &peer->mac, mac, sizeof ( peer->mac ) );
        list_add ( &peer->list, &ipoib->peers );

        return 0;
}

/**
 * Flush REMAC cache
 *
 * @v ipoib             IPoIB device
 */
static void ipoib_flush_remac ( struct ipoib_device *ipoib ) {
        struct ipoib_peer *peer;
        struct ipoib_peer *tmp;

        list_for_each_entry_safe ( peer, tmp, &ipoib->peers, list ) {
                list_del ( &peer->list );
                free ( peer );
        }
}

/**
 * Discard some entries from the REMAC cache
 *
 * @ret discarded       Number of cached items discarded
 */
static unsigned int ipoib_discard_remac ( void ) {
        struct net_device *netdev;
        struct ipoib_device *ipoib;
        struct ipoib_peer *peer;
        unsigned int discarded = 0;

        /* Try to discard one cache entry for each IPoIB device */
        for_each_netdev ( netdev ) {

                /* Skip non-IPoIB devices */
                if ( netdev->op != &ipoib_operations )
                        continue;
                ipoib = netdev->priv;

                /* Discard least recently used cache entry (if any) */
                list_for_each_entry_reverse ( peer, &ipoib->peers, list ) {
                        list_del ( &peer->list );
                        free ( peer );
                        discarded++;
                        break;
                }
        }

        return discarded;
}

/** IPoIB cache discarder */
struct cache_discarder ipoib_discarder __cache_discarder ( CACHE_EXPENSIVE ) = {
        .discard = ipoib_discard_remac,
};

/****************************************************************************
 *
 * IPoIB link layer
 *
 ****************************************************************************
 */

/**
 * Initialise IPoIB link-layer address
 *
 * @v hw_addr           Hardware address
 * @v ll_addr           Link-layer address
 */
static void ipoib_init_addr ( const void *hw_addr, void *ll_addr ) {
        const uint8_t *guid = hw_addr;
        uint8_t *eth_addr = ll_addr;
        uint8_t guid_mask = IPOIB_GUID_MASK;
        unsigned int i;

        /* Extract bytes from GUID according to mask */
        for ( i = 0 ; i < 8 ; i++, guid++, guid_mask <<= 1 ) {
                if ( guid_mask & 0x80 )
                        *(eth_addr++) = *guid;
        }
}

/** IPoIB protocol */
struct ll_protocol ipoib_protocol __ll_protocol = {
        .name           = "IPoIB",
        .ll_proto       = htons ( ARPHRD_ETHER ),
        .hw_addr_len    = sizeof ( union ib_guid ),
        .ll_addr_len    = ETH_ALEN,
        .ll_header_len  = ETH_HLEN,
        .push           = eth_push,
        .pull           = eth_pull,
        .init_addr      = ipoib_init_addr,
        .ntoa           = eth_ntoa,
        .mc_hash        = eth_mc_hash,
        .eth_addr       = eth_eth_addr,
        .eui64          = eth_eui64,
        .flags          = LL_NAME_ONLY,
};

/**
 * Allocate IPoIB device
 *
 * @v priv_size         Size of driver private data
 * @ret netdev          Network device, or NULL
 */
struct net_device * alloc_ipoibdev ( size_t priv_size ) {
        struct net_device *netdev;

        netdev = alloc_netdev ( priv_size );
        if ( netdev ) {
                netdev->ll_protocol = &ipoib_protocol;
                netdev->ll_broadcast = eth_broadcast;
                netdev->max_pkt_len = IB_MAX_PAYLOAD_SIZE;
        }
        return netdev;
}

/****************************************************************************
 *
 * IPoIB translation layer
 *
 ****************************************************************************
 */

/**
 * Translate transmitted ARP packet
 *
 * @v netdev            Network device
 * @v iobuf             Packet to be transmitted (with no link-layer headers)
 * @ret rc              Return status code
 */
static int ipoib_translate_tx_arp ( struct net_device *netdev,
                                    struct io_buffer *iobuf ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct arphdr *arphdr = iobuf->data;
        struct ipoib_mac *target_ha = NULL;
        void *sender_pa;
        void *target_pa;

        /* Do nothing unless ARP contains eIPoIB link-layer addresses */
        if ( arphdr->ar_hln != ETH_ALEN )
                return 0;

        /* Fail unless we have room to expand packet */
        if ( iob_tailroom ( iobuf ) < ( 2 * ( sizeof ( ipoib->mac ) -
                                              ETH_ALEN ) ) ) {
                DBGC ( ipoib, "IPoIB %p insufficient space in TX ARP\n",
                       ipoib );
                return -ENOBUFS;
        }

        /* Look up REMAC, if applicable */
        if ( arphdr->ar_op == ARPOP_REPLY ) {
                target_ha = ipoib_find_remac ( ipoib, arp_target_pa ( arphdr ));
                if ( ! target_ha ) {
                        DBGC ( ipoib, "IPoIB %p no REMAC for %s ARP reply\n",
                               ipoib, eth_ntoa ( arp_target_pa ( arphdr ) ) );
                        return -ENXIO_ARP_REPLY;
                }
        }

        /* Construct new packet */
        iob_put ( iobuf, ( 2 * ( sizeof ( ipoib->mac ) - ETH_ALEN ) ) );
        sender_pa = arp_sender_pa ( arphdr );
        target_pa = arp_target_pa ( arphdr );
        arphdr->ar_hrd = htons ( ARPHRD_INFINIBAND );
        arphdr->ar_hln = sizeof ( ipoib->mac );
        memcpy ( arp_target_pa ( arphdr ), target_pa, arphdr->ar_pln );
        memcpy ( arp_sender_pa ( arphdr ), sender_pa, arphdr->ar_pln );
        memcpy ( arp_sender_ha ( arphdr ), &ipoib->mac, sizeof ( ipoib->mac ) );
        memset ( arp_target_ha ( arphdr ), 0, sizeof ( ipoib->mac ) );
        if ( target_ha ) {
                memcpy ( arp_target_ha ( arphdr ), target_ha,
                         sizeof ( *target_ha ) );
        }

        return 0;
}

/**
 * Translate transmitted packet
 *
 * @v netdev            Network device
 * @v iobuf             Packet to be transmitted (with no link-layer headers)
 * @v net_proto         Network-layer protocol (in network byte order)
 * @ret rc              Return status code
 */
static int ipoib_translate_tx ( struct net_device *netdev,
                                struct io_buffer *iobuf, uint16_t net_proto ) {

        switch ( net_proto ) {
        case htons ( ETH_P_ARP ) :
                return ipoib_translate_tx_arp ( netdev, iobuf );
        case htons ( ETH_P_IP ) :
                /* No translation needed */
                return 0;
        default:
                /* Cannot handle other traffic via eIPoIB */
                return -ENOTSUP;
        }
}

/**
 * Translate received ARP packet
 *
 * @v netdev            Network device
 * @v iobuf             Received packet (with no link-layer headers)
 * @v remac             Constructed Remote Ethernet MAC
 * @ret rc              Return status code
 */
static int ipoib_translate_rx_arp ( struct net_device *netdev,
                                    struct io_buffer *iobuf,
                                    struct ipoib_remac *remac ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct arphdr *arphdr = iobuf->data;
        void *sender_pa;
        void *target_pa;
        int rc;

        /* Do nothing unless ARP contains IPoIB link-layer addresses */
        if ( arphdr->ar_hln != sizeof ( ipoib->mac ) )
                return 0;

        /* Create REMAC cache entry */
        if ( ( rc = ipoib_map_remac ( ipoib, remac,
                                      arp_sender_ha ( arphdr ) ) ) != 0 ) {
                DBGC ( ipoib, "IPoIB %p could not map REMAC: %s\n",
                       ipoib, strerror ( rc ) );
                return rc;
        }

        /* Construct new packet */
        sender_pa = arp_sender_pa ( arphdr );
        target_pa = arp_target_pa ( arphdr );
        arphdr->ar_hrd = htons ( ARPHRD_ETHER );
        arphdr->ar_hln = ETH_ALEN;
        memcpy ( arp_sender_pa ( arphdr ), sender_pa, arphdr->ar_pln );
        memcpy ( arp_target_pa ( arphdr ), target_pa, arphdr->ar_pln );
        memcpy ( arp_sender_ha ( arphdr ), remac, ETH_ALEN );
        memset ( arp_target_ha ( arphdr ), 0, ETH_ALEN );
        if ( arphdr->ar_op == ARPOP_REPLY ) {
                /* Assume received replies were directed to us */
                memcpy ( arp_target_ha ( arphdr ), netdev->ll_addr, ETH_ALEN );
        }
        iob_unput ( iobuf, ( 2 * ( sizeof ( ipoib->mac ) - ETH_ALEN ) ) );

        return 0;
}

/**
 * Translate received packet
 *
 * @v netdev            Network device
 * @v iobuf             Received packet (with no link-layer headers)
 * @v remac             Constructed Remote Ethernet MAC
 * @v net_proto         Network-layer protocol (in network byte order)
 * @ret rc              Return status code
 */
static int ipoib_translate_rx ( struct net_device *netdev,
                                struct io_buffer *iobuf,
                                struct ipoib_remac *remac,
                                uint16_t net_proto ) {

        switch ( net_proto ) {
        case htons ( ETH_P_ARP ) :
                return ipoib_translate_rx_arp ( netdev, iobuf, remac );
        case htons ( ETH_P_IP ) :
                /* No translation needed */
                return 0;
        default:
                /* Cannot handle other traffic via eIPoIB */
                return -ENOTSUP;
        }
}

/****************************************************************************
 *
 * IPoIB network device
 *
 ****************************************************************************
 */

/**
 * Transmit packet via IPoIB network device
 *
 * @v netdev            Network device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int ipoib_transmit ( struct net_device *netdev,
                            struct io_buffer *iobuf ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct ib_device *ibdev = ipoib->ibdev;
        struct ethhdr *ethhdr;
        struct iphdr *iphdr;
        struct ipoib_hdr *ipoib_hdr;
        struct ipoib_remac *remac;
        struct ipoib_mac *mac;
        struct ib_address_vector *dest;
        struct ib_address_vector av;
        uint16_t net_proto;
        int rc;

        /* Sanity check */
        if ( iob_len ( iobuf ) < sizeof ( *ethhdr ) ) {
                DBGC ( ipoib, "IPoIB %p buffer too short\n", ipoib );
                return -EINVAL;
        }

        /* Attempting transmission while link is down will put the
         * queue pair into an error state, so don't try it.
         */
        if ( ! ib_link_ok ( ibdev ) )
                return -ENETUNREACH;

        /* Strip eIPoIB header */
        ethhdr = iobuf->data;
        remac = ( ( struct ipoib_remac * ) ethhdr->h_dest );
        net_proto = ethhdr->h_protocol;
        iob_pull ( iobuf, sizeof ( *ethhdr ) );

        /* Identify destination address */
        if ( is_multicast_ether_addr ( remac ) ) {

                /* Transmit multicasts as broadcasts, for simplicity */
                dest = &ipoib->broadcast.av;

        } else if ( ( mac = ipoib_find_remac ( ipoib, remac ) ) ) {

                /* Construct address vector from IPoIB MAC */
                dest = &av;
                memset ( dest, 0, sizeof ( *dest ) );
                dest->qpn = ( ntohl ( mac->flags__qpn ) & IB_QPN_MASK );
                dest->qkey = ipoib->broadcast.av.qkey;
                dest->gid_present = 1;
                memcpy ( &dest->gid, &mac->gid, sizeof ( dest->gid ) );
                if ( ( rc = ib_resolve_path ( ibdev, dest ) ) != 0 ) {
                        /* Path not resolved yet */
                        return rc;
                }

        } else {

                /* Generate a new ARP request (if possible) to trigger
                 * population of the REMAC cache entry.
                 */
                if ( ( net_proto != htons ( ETH_P_IP ) ) ||
                     ( iob_len ( iobuf ) < sizeof ( *iphdr ) ) ) {
                        DBGC ( ipoib, "IPoIB %p no REMAC for %s non-IPv4 "
                               "packet type %04x\n", ipoib,
                               eth_ntoa ( ethhdr->h_dest ),
                               ntohs ( net_proto ) );
                        return -ENXIO_NON_IPV4;
                }
                iphdr = iobuf->data;
                if ( ( rc = arp_tx_request ( netdev, &ipv4_protocol,
                                             &iphdr->dest, &iphdr->src ) ) !=0){
                        DBGC ( ipoib, "IPoIB %p could not ARP for %s/%s/",
                               ipoib, eth_ntoa ( ethhdr->h_dest ),
                               inet_ntoa ( iphdr->dest ) );
                        DBGC ( ipoib, "%s: %s\n", inet_ntoa ( iphdr->src ),
                               strerror ( rc ) );
                        return rc;
                }
                DBGC ( ipoib, "IPoIB %p no REMAC for %s/%s/", ipoib,
                       eth_ntoa ( ethhdr->h_dest ), inet_ntoa ( iphdr->dest ) );
                DBGC  ( ipoib, "%s\n", inet_ntoa ( iphdr->src ) );
                return -ENXIO_ARP_SENT;
        }

        /* Translate packet if applicable */
        if ( ( rc = ipoib_translate_tx ( netdev, iobuf, net_proto ) ) != 0 )
                return rc;

        /* Prepend real IPoIB header */
        ipoib_hdr = iob_push ( iobuf, sizeof ( *ipoib_hdr ) );
        ipoib_hdr->proto = net_proto;
        ipoib_hdr->reserved = 0;

        /* Transmit packet */
        return ib_post_send ( ibdev, ipoib->qp, dest, iobuf );
}

/**
 * Handle IPoIB send completion
 *
 * @v ibdev             Infiniband device
 * @v qp                Queue pair
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void ipoib_complete_send ( struct ib_device *ibdev __unused,
                                  struct ib_queue_pair *qp,
                                  struct io_buffer *iobuf, int rc ) {
        struct ipoib_device *ipoib = ib_qp_get_ownerdata ( qp );

        netdev_tx_complete_err ( ipoib->netdev, iobuf, rc );
}

/**
 * Handle IPoIB receive completion
 *
 * @v ibdev             Infiniband device
 * @v qp                Queue pair
 * @v dest              Destination address vector, or NULL
 * @v source            Source address vector, or NULL
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void ipoib_complete_recv ( struct ib_device *ibdev __unused,
                                  struct ib_queue_pair *qp,
                                  struct ib_address_vector *dest,
                                  struct ib_address_vector *source,
                                  struct io_buffer *iobuf, int rc ) {
        struct ipoib_device *ipoib = ib_qp_get_ownerdata ( qp );
        struct net_device *netdev = ipoib->netdev;
        struct ipoib_hdr *ipoib_hdr;
        struct ethhdr *ethhdr;
        struct ipoib_remac remac;
        uint16_t net_proto;

        /* Record errors */
        if ( rc != 0 ) {
                netdev_rx_err ( netdev, iobuf, rc );
                return;
        }

        /* Sanity check */
        if ( iob_len ( iobuf ) < sizeof ( struct ipoib_hdr ) ) {
                DBGC ( ipoib, "IPoIB %p received packet too short to "
                       "contain IPoIB header\n", ipoib );
                DBGC_HD ( ipoib, iobuf->data, iob_len ( iobuf ) );
                netdev_rx_err ( netdev, iobuf, -EIO );
                return;
        }
        if ( ! source ) {
                DBGC ( ipoib, "IPoIB %p received packet without address "
                       "vector\n", ipoib );
                netdev_rx_err ( netdev, iobuf, -ENOTTY );
                return;
        }

        /* Strip real IPoIB header */
        ipoib_hdr = iobuf->data;
        net_proto = ipoib_hdr->proto;
        iob_pull ( iobuf, sizeof ( *ipoib_hdr ) );

        /* Construct source address from remote QPN and LID */
        remac.qpn = htonl ( source->qpn | EIPOIB_QPN_LA );
        remac.lid = htons ( source->lid );

        /* Translate packet if applicable */
        if ( ( rc = ipoib_translate_rx ( netdev, iobuf, &remac,
                                         net_proto ) ) != 0 ) {
                netdev_rx_err ( netdev, iobuf, rc );
                return;
        }

        /* Prepend eIPoIB header */
        ethhdr = iob_push ( iobuf, sizeof ( *ethhdr ) );
        memcpy ( &ethhdr->h_source, &remac, sizeof ( ethhdr->h_source ) );
        ethhdr->h_protocol = net_proto;

        /* Construct destination address */
        if ( dest->gid_present && IB_GID_MULTICAST ( &dest->gid ) ) {
                /* Multicast GID: use the Ethernet broadcast address */
                memcpy ( &ethhdr->h_dest, eth_broadcast,
                         sizeof ( ethhdr->h_dest ) );
        } else {
                /* Assume destination address is local Ethernet MAC */
                memcpy ( &ethhdr->h_dest, netdev->ll_addr,
                         sizeof ( ethhdr->h_dest ) );
        }

        /* Hand off to network layer */
        netdev_rx ( netdev, iobuf );
}

/** IPoIB completion operations */
static struct ib_completion_queue_operations ipoib_cq_op = {
        .complete_send = ipoib_complete_send,
        .complete_recv = ipoib_complete_recv,
};

/**
 * Allocate IPoIB receive I/O buffer
 *
 * @v len               Length of buffer
 * @ret iobuf           I/O buffer, or NULL
 *
 * Some Infiniband hardware requires 2kB alignment of receive buffers
 * and provides no way to disable header separation.  The result is
 * that there are only four bytes of link-layer header (the real IPoIB
 * header) before the payload.  This is not sufficient space to insert
 * an eIPoIB link-layer pseudo-header.
 *
 * We therefore allocate I/O buffers offset to start slightly before
 * the natural alignment boundary, in order to allow sufficient space.
 */
static struct io_buffer * ipoib_alloc_iob ( size_t len ) {
        struct io_buffer *iobuf;
        size_t reserve_len;

        /* Calculate additional length required at start of buffer */
        reserve_len = ( sizeof ( struct ethhdr ) -
                        sizeof ( struct ipoib_hdr ) );

        /* Allocate buffer */
        iobuf = alloc_iob_raw ( ( len + reserve_len ), len, -reserve_len );
        if ( iobuf ) {
                iob_reserve ( iobuf, reserve_len );
        }
        return iobuf;
}

/** IPoIB queue pair operations */
static struct ib_queue_pair_operations ipoib_qp_op = {
        .alloc_iob = ipoib_alloc_iob,
};

/**
 * Poll IPoIB network device
 *
 * @v netdev            Network device
 */
static void ipoib_poll ( struct net_device *netdev ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct ib_device *ibdev = ipoib->ibdev;

        /* Poll Infiniband device */
        ib_poll_eq ( ibdev );

        /* Poll the retry timers (required for IPoIB multicast join) */
        retry_poll();
}

/**
 * Handle IPv4 broadcast multicast group join completion
 *
 * @v membership        Multicast group membership
 * @v rc                Status code
 */
void ipoib_join_complete ( struct ib_mc_membership *membership, int rc ) {
        struct ipoib_device *ipoib = container_of ( membership,
                                                    struct ipoib_device,
                                                    broadcast.membership );

        /* Record join status as link status */
        netdev_link_err ( ipoib->netdev, rc );
}

/**
 * Join IPv4 broadcast multicast group
 *
 * @v ipoib             IPoIB device
 * @ret rc              Return status code
 */
static int ipoib_join_broadcast_group ( struct ipoib_device *ipoib ) {
        int rc;

        /* Join multicast group */
        if ( ( rc = ib_mcast_join ( ipoib->ibdev, ipoib->qp,
                                    &ipoib->broadcast.membership,
                                    &ipoib->broadcast.av, 0,
                                    ipoib_join_complete ) ) != 0 ) {
                DBGC ( ipoib, "IPoIB %p could not join broadcast group: %s\n",
                       ipoib, strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Leave IPv4 broadcast multicast group
 *
 * @v ipoib             IPoIB device
 */
static void ipoib_leave_broadcast_group ( struct ipoib_device *ipoib ) {

        /* Leave multicast group */
        ib_mcast_leave ( ipoib->ibdev, ipoib->qp,
                         &ipoib->broadcast.membership );
}

/**
 * Handle link status change
 *
 * @v ipoib             IPoIB device
 */
static void ipoib_link_state_changed ( struct ipoib_device *ipoib ) {
        struct ib_device *ibdev = ipoib->ibdev;
        struct net_device *netdev = ipoib->netdev;
        int rc;

        /* Leave existing broadcast group */
        if ( ipoib->qp )
                ipoib_leave_broadcast_group ( ipoib );

        /* Update MAC address based on potentially-new GID prefix */
        memcpy ( &ipoib->mac.gid.s.prefix, &ibdev->gid.s.prefix,
                 sizeof ( ipoib->mac.gid.s.prefix ) );

        /* Update broadcast MAC GID based on potentially-new partition key */
        ipoib->broadcast.mac.gid.words[2] =
                htons ( ibdev->pkey | IB_PKEY_FULL );

        /* Construct broadcast address vector from broadcast MAC address */
        memset ( &ipoib->broadcast.av, 0, sizeof ( ipoib->broadcast.av ) );
        ipoib->broadcast.av.qpn = IB_QPN_BROADCAST;
        ipoib->broadcast.av.gid_present = 1;
        memcpy ( &ipoib->broadcast.av.gid, &ipoib->broadcast.mac.gid,
                 sizeof ( ipoib->broadcast.av.gid ) );

        /* Set net device link state to reflect Infiniband link state */
        rc = ib_link_rc ( ibdev );
        netdev_link_err ( netdev, ( rc ? rc : -EINPROGRESS_JOINING ) );

        /* Join new broadcast group */
        if ( ib_is_open ( ibdev ) && ib_link_ok ( ibdev ) && ipoib->qp &&
             ( ( rc = ipoib_join_broadcast_group ( ipoib ) ) != 0 ) ) {
                DBGC ( ipoib, "IPoIB %p could not rejoin broadcast group: "
                       "%s\n", ipoib, strerror ( rc ) );
                netdev_link_err ( netdev, rc );
                return;
        }
}

/**
 * Open IPoIB network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int ipoib_open ( struct net_device *netdev ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct ib_device *ibdev = ipoib->ibdev;
        int rc;

        /* Open IB device */
        if ( ( rc = ib_open ( ibdev ) ) != 0 ) {
                DBGC ( ipoib, "IPoIB %p could not open device: %s\n",
                       ipoib, strerror ( rc ) );
                goto err_ib_open;
        }

        /* Allocate completion queue */
        if ( ( rc = ib_create_cq ( ibdev, IPOIB_NUM_CQES, &ipoib_cq_op,
                                   &ipoib->cq ) ) != 0 ) {
                DBGC ( ipoib, "IPoIB %p could not create completion queue: "
                       "%s\n", ipoib, strerror ( rc ) );
                goto err_create_cq;
        }

        /* Allocate queue pair */
        if ( ( rc = ib_create_qp ( ibdev, IB_QPT_UD, IPOIB_NUM_SEND_WQES,
                                   ipoib->cq, IPOIB_NUM_RECV_WQES, ipoib->cq,
                                   &ipoib_qp_op, netdev->name,
                                   &ipoib->qp ) ) != 0 ) {
                DBGC ( ipoib, "IPoIB %p could not create queue pair: %s\n",
                       ipoib, strerror ( rc ) );
                goto err_create_qp;
        }
        ib_qp_set_ownerdata ( ipoib->qp, ipoib );

        /* Update MAC address with QPN */
        ipoib->mac.flags__qpn = htonl ( ipoib->qp->qpn );

        /* Fill receive rings */
        ib_refill_recv ( ibdev, ipoib->qp );

        /* Fake a link status change to join the broadcast group */
        ipoib_link_state_changed ( ipoib );

        return 0;

        ib_destroy_qp ( ibdev, ipoib->qp );
 err_create_qp:
        ib_destroy_cq ( ibdev, ipoib->cq );
 err_create_cq:
        ib_close ( ibdev );
 err_ib_open:
        return rc;
}

/**
 * Close IPoIB network device
 *
 * @v netdev            Network device
 */
static void ipoib_close ( struct net_device *netdev ) {
        struct ipoib_device *ipoib = netdev->priv;
        struct ib_device *ibdev = ipoib->ibdev;

        /* Flush REMAC cache */
        ipoib_flush_remac ( ipoib );

        /* Leave broadcast group */
        ipoib_leave_broadcast_group ( ipoib );

        /* Remove QPN from MAC address */
        ipoib->mac.flags__qpn = 0;

        /* Tear down the queues */
        ib_destroy_qp ( ibdev, ipoib->qp );
        ipoib->qp = NULL;
        ib_destroy_cq ( ibdev, ipoib->cq );
        ipoib->cq = NULL;

        /* Close IB device */
        ib_close ( ibdev );
}

/** IPoIB network device operations */
static struct net_device_operations ipoib_operations = {
        .open           = ipoib_open,
        .close          = ipoib_close,
        .transmit       = ipoib_transmit,
        .poll           = ipoib_poll,
};

/**
 * Probe IPoIB device
 *
 * @v ibdev             Infiniband device
 * @ret rc              Return status code
 */
static int ipoib_probe ( struct ib_device *ibdev ) {
        struct net_device *netdev;
        struct ipoib_device *ipoib;
        int rc;

        /* Allocate network device */
        netdev = alloc_ipoibdev ( sizeof ( *ipoib ) );
        if ( ! netdev )
                return -ENOMEM;
        netdev_init ( netdev, &ipoib_operations );
        ipoib = netdev->priv;
        netdev->dev = ibdev->dev;
        memset ( ipoib, 0, sizeof ( *ipoib ) );
        ipoib->netdev = netdev;
        ipoib->ibdev = ibdev;
        INIT_LIST_HEAD ( &ipoib->peers );

        /* Extract hardware address */
        memcpy ( netdev->hw_addr, &ibdev->gid.s.guid,
                 sizeof ( ibdev->gid.s.guid ) );
        memcpy ( netdev->ll_addr, ibdev->lemac, ETH_ALEN );

        /* Set local MAC address */
        memcpy ( &ipoib->mac.gid.s.guid, &ibdev->gid.s.guid,
                 sizeof ( ipoib->mac.gid.s.guid ) );

        /* Set default broadcast MAC address */
        memcpy ( &ipoib->broadcast.mac, &ipoib_broadcast,
                 sizeof ( ipoib->broadcast.mac ) );

        /* Add to list of IPoIB devices */
        list_add_tail ( &ipoib->list, &ipoib_devices );

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err_register_netdev;

        return 0;

        unregister_netdev ( netdev );
 err_register_netdev:
        list_del ( &ipoib->list );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
        return rc;
}

/**
 * Handle device or link status change
 *
 * @v ibdev             Infiniband device
 */
static void ipoib_notify ( struct ib_device *ibdev ) {
        struct ipoib_device *ipoib;

        /* Handle link status change for any attached IPoIB devices */
        list_for_each_entry ( ipoib, &ipoib_devices, list ) {
                if ( ipoib->ibdev != ibdev )
                        continue;
                ipoib_link_state_changed ( ipoib );
        }
}

/**
 * Remove IPoIB device
 *
 * @v ibdev             Infiniband device
 */
static void ipoib_remove ( struct ib_device *ibdev ) {
        struct ipoib_device *ipoib;
        struct ipoib_device *tmp;
        struct net_device *netdev;

        /* Remove any attached IPoIB devices */
        list_for_each_entry_safe ( ipoib, tmp, &ipoib_devices, list ) {
                if ( ipoib->ibdev != ibdev )
                        continue;
                netdev = ipoib->netdev;
                unregister_netdev ( netdev );
                list_del ( &ipoib->list );
                netdev_nullify ( netdev );
                netdev_put ( netdev );
        }
}

/** IPoIB driver */
struct ib_driver ipoib_driver __ib_driver = {
        .name = "IPoIB",
        .probe = ipoib_probe,
        .notify = ipoib_notify,
        .remove = ipoib_remove,
};

/**
 * Find IPoIB network device
 *
 * @v ibdev             Infiniband device
 * @ret netdev          IPoIB network device, or NULL if not found
 */
struct net_device * ipoib_netdev ( struct ib_device *ibdev ) {
        struct ipoib_device *ipoib;

        /* Find matching IPoIB device */
        list_for_each_entry ( ipoib, &ipoib_devices, list ) {
                if ( ipoib->ibdev != ibdev )
                        continue;
                return ipoib->netdev;
        }
        return NULL;
}