smi.c

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/*
 * Copyright (c) 2004, 2005 Mellanox Technologies Ltd.  All rights reserved.
 * Copyright (c) 2004, 2005 Infinicon Corporation.  All rights reserved.
 * Copyright (c) 2004, 2005 Intel Corporation.  All rights reserved.
 * Copyright (c) 2004, 2005 Topspin Corporation.  All rights reserved.
 * Copyright (c) 2004-2007 Voltaire Corporation.  All rights reserved.
 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#include <rdma/ib_smi.h>
#include "smi.h"

/*
 * Fixup a directed route SMP for sending
 * Return 0 if the SMP should be discarded
 */
enum smi_action smi_handle_dr_smp_send(struct ib_smp *smp,
                       u8 node_type, int port_num)
{
    u8 hop_ptr, hop_cnt;

    hop_ptr = smp->hop_ptr;
    hop_cnt = smp->hop_cnt;

    /* See section 14.2.2.2, Vol 1 IB spec */
    /* C14-6 -- valid hop_cnt values are from 0 to 63 */
    if (hop_cnt >= IB_SMP_MAX_PATH_HOPS)
        return IB_SMI_DISCARD;

    if (!ib_get_smp_direction(smp)) {
        /* C14-9:1 */
        if (hop_cnt && hop_ptr == 0) {
            smp->hop_ptr++;
            return (smp->initial_path[smp->hop_ptr] ==
                port_num ? IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-9:2 */
        if (hop_ptr && hop_ptr < hop_cnt) {
            if (node_type != RDMA_NODE_IB_SWITCH)
                return IB_SMI_DISCARD;

            /* smp->return_path set when received */
            smp->hop_ptr++;
            return (smp->initial_path[smp->hop_ptr] ==
                port_num ? IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-9:3 -- We're at the end of the DR segment of path */
        if (hop_ptr == hop_cnt) {
            /* smp->return_path set when received */
            smp->hop_ptr++;
            return (node_type == RDMA_NODE_IB_SWITCH ||
                smp->dr_dlid == IB_LID_PERMISSIVE ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-9:4 -- hop_ptr = hop_cnt + 1 -> give to SMA/SM */
        /* C14-9:5 -- Fail unreasonable hop pointer */
        return (hop_ptr == hop_cnt + 1 ? IB_SMI_HANDLE : IB_SMI_DISCARD);

    } else {
        /* C14-13:1 */
        if (hop_cnt && hop_ptr == hop_cnt + 1) {
            smp->hop_ptr--;
            return (smp->return_path[smp->hop_ptr] ==
                port_num ? IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:2 */
        if (2 <= hop_ptr && hop_ptr <= hop_cnt) {
            if (node_type != RDMA_NODE_IB_SWITCH)
                return IB_SMI_DISCARD;

            smp->hop_ptr--;
            return (smp->return_path[smp->hop_ptr] ==
                port_num ? IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:3 -- at the end of the DR segment of path */
        if (hop_ptr == 1) {
            smp->hop_ptr--;
            /* C14-13:3 -- SMPs destined for SM shouldn't be here */
            return (node_type == RDMA_NODE_IB_SWITCH ||
                smp->dr_slid == IB_LID_PERMISSIVE ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:4 -- hop_ptr = 0 -> should have gone to SM */
        if (hop_ptr == 0)
            return IB_SMI_HANDLE;

        /* C14-13:5 -- Check for unreasonable hop pointer */
        return IB_SMI_DISCARD;
    }
}

/*
 * Adjust information for a received SMP
 * Return 0 if the SMP should be dropped
 */
enum smi_action smi_handle_dr_smp_recv(struct ib_smp *smp, u8 node_type,
                       int port_num, int phys_port_cnt)
{
    u8 hop_ptr, hop_cnt;

    hop_ptr = smp->hop_ptr;
    hop_cnt = smp->hop_cnt;

    /* See section 14.2.2.2, Vol 1 IB spec */
    /* C14-6 -- valid hop_cnt values are from 0 to 63 */
    if (hop_cnt >= IB_SMP_MAX_PATH_HOPS)
        return IB_SMI_DISCARD;

    if (!ib_get_smp_direction(smp)) {
        /* C14-9:1 -- sender should have incremented hop_ptr */
        if (hop_cnt && hop_ptr == 0)
            return IB_SMI_DISCARD;

        /* C14-9:2 -- intermediate hop */
        if (hop_ptr && hop_ptr < hop_cnt) {
            if (node_type != RDMA_NODE_IB_SWITCH)
                return IB_SMI_DISCARD;

            smp->return_path[hop_ptr] = port_num;
            /* smp->hop_ptr updated when sending */
            return (smp->initial_path[hop_ptr+1] <= phys_port_cnt ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-9:3 -- We're at the end of the DR segment of path */
        if (hop_ptr == hop_cnt) {
            if (hop_cnt)
                smp->return_path[hop_ptr] = port_num;
            /* smp->hop_ptr updated when sending */

            return (node_type == RDMA_NODE_IB_SWITCH ||
                smp->dr_dlid == IB_LID_PERMISSIVE ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-9:4 -- hop_ptr = hop_cnt + 1 -> give to SMA/SM */
        /* C14-9:5 -- fail unreasonable hop pointer */
        return (hop_ptr == hop_cnt + 1 ? IB_SMI_HANDLE : IB_SMI_DISCARD);

    } else {

        /* C14-13:1 */
        if (hop_cnt && hop_ptr == hop_cnt + 1) {
            smp->hop_ptr--;
            return (smp->return_path[smp->hop_ptr] ==
                port_num ? IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:2 */
        if (2 <= hop_ptr && hop_ptr <= hop_cnt) {
            if (node_type != RDMA_NODE_IB_SWITCH)
                return IB_SMI_DISCARD;

            /* smp->hop_ptr updated when sending */
            return (smp->return_path[hop_ptr-1] <= phys_port_cnt ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:3 -- We're at the end of the DR segment of path */
        if (hop_ptr == 1) {
            if (smp->dr_slid == IB_LID_PERMISSIVE) {
                /* giving SMP to SM - update hop_ptr */
                smp->hop_ptr--;
                return IB_SMI_HANDLE;
            }
            /* smp->hop_ptr updated when sending */
            return (node_type == RDMA_NODE_IB_SWITCH ?
                IB_SMI_HANDLE : IB_SMI_DISCARD);
        }

        /* C14-13:4 -- hop_ptr = 0 -> give to SM */
        /* C14-13:5 -- Check for unreasonable hop pointer */
        return (hop_ptr == 0 ? IB_SMI_HANDLE : IB_SMI_DISCARD);
    }
}

enum smi_forward_action smi_check_forward_dr_smp(struct ib_smp *smp)
{
    u8 hop_ptr, hop_cnt;

    hop_ptr = smp->hop_ptr;
    hop_cnt = smp->hop_cnt;

    if (!ib_get_smp_direction(smp)) {
        /* C14-9:2 -- intermediate hop */
        if (hop_ptr && hop_ptr < hop_cnt)
            return IB_SMI_FORWARD;

        /* C14-9:3 -- at the end of the DR segment of path */
        if (hop_ptr == hop_cnt)
            return (smp->dr_dlid == IB_LID_PERMISSIVE ?
                IB_SMI_SEND : IB_SMI_LOCAL);

        /* C14-9:4 -- hop_ptr = hop_cnt + 1 -> give to SMA/SM */
        if (hop_ptr == hop_cnt + 1)
            return IB_SMI_SEND;
    } else {
        /* C14-13:2  -- intermediate hop */
        if (2 <= hop_ptr && hop_ptr <= hop_cnt)
            return IB_SMI_FORWARD;

        /* C14-13:3 -- at the end of the DR segment of path */
        if (hop_ptr == 1)
            return (smp->dr_slid != IB_LID_PERMISSIVE ?
                IB_SMI_SEND : IB_SMI_LOCAL);
    }
    return IB_SMI_LOCAL;
}

/*
 * Return the forwarding port number from initial_path for outgoing SMP and
 * from return_path for returning SMP
 */
int smi_get_fwd_port(struct ib_smp *smp)
{
    return (!ib_get_smp_direction(smp) ? smp->initial_path[smp->hop_ptr+1] :
        smp->return_path[smp->hop_ptr-1]);
}