/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 * Modifications for Lustre
 * Copyright 2004, Cluster File Systems, Inc.
 * All rights reserved
 * Author: Eric Mei <ericm@clusterfs.com>
 */

/*
 *  linux/net/sunrpc/gss_mech_switch.c
 *
 *  Copyright (c) 2001 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  J. Bruce Fields   <bfields@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. 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.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef EXPORT_SYMTAB
# define EXPORT_SYMTAB
#endif
#define DEBUG_SUBSYSTEM S_SEC
#ifdef __KERNEL__
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#else
#include <liblustre.h>
#endif

#include <libcfs/kp30.h>
#include <linux/obd.h>
#include <linux/obd_class.h>
#include <linux/obd_support.h>
#include <linux/lustre_idl.h>
#include <linux/lustre_net.h>
#include <linux/lustre_import.h>
#include <linux/lustre_sec.h>

#include "gss_err.h"
#include "gss_internal.h"
#include "gss_api.h"

static LIST_HEAD(registered_mechs);
static spinlock_t registered_mechs_lock = SPIN_LOCK_UNLOCKED;

int
kgss_mech_register(struct gss_api_mech *gm)
{
        spin_lock(&registered_mechs_lock);
        list_add(&gm->gm_list, &registered_mechs);
        spin_unlock(&registered_mechs_lock);
        CWARN("registered gss mechanism %s\n", gm->gm_name);
        return 0;
}

//EXPORT_SYMBOL(kgss_mech_register);

void
kgss_mech_unregister(struct gss_api_mech *gm)
{
        spin_lock(&registered_mechs_lock);
        list_del(&gm->gm_list);
        spin_unlock(&registered_mechs_lock);
        CWARN("unregistered gss mechanism %s\n", gm->gm_name);
//        gss_mech_free(gm);
}

//EXPORT_SYMBOL(gss_mech_unregister);

struct gss_api_mech *
kgss_mech_get(struct gss_api_mech *gm)
{
        __module_get(gm->gm_owner);
        return gm;
}

//EXPORT_SYMBOL(kgss_mech_get);

struct gss_api_mech *
kgss_name_to_mech(char *name)
{
        struct gss_api_mech *pos, *gm = NULL;

        spin_lock(&registered_mechs_lock);
        list_for_each_entry(pos, &registered_mechs, gm_list) {
                if (0 == strcmp(name, pos->gm_name)) {
                        if (!try_module_get(pos->gm_owner))
                                continue;
                        gm = pos;
                        break;
                }
        }
        spin_unlock(&registered_mechs_lock);
        return gm;

}

//EXPORT_SYMBOL(gss_name_to_mech);

static inline int
mech_supports_subflavor(struct gss_api_mech *gm, __u32 subflavor)
{
        int i;

        for (i = 0; i < gm->gm_sf_num; i++) {
                if (gm->gm_sfs[i].subflavor == subflavor)
                        return 1;
        }
        return 0;
}

struct gss_api_mech *
kgss_subflavor_to_mech(__u32 subflavor)
{
        struct gss_api_mech *pos, *gm = NULL;

        spin_lock(&registered_mechs_lock);
        list_for_each_entry(pos, &registered_mechs, gm_list) {
                if (!try_module_get(pos->gm_owner))
                        continue;
                if (!mech_supports_subflavor(pos, subflavor)) {
                        module_put(pos->gm_owner);
                        continue;
                }
                gm = pos;
                break;
        }
        spin_unlock(&registered_mechs_lock);
        return gm;
}

//EXPORT_SYMBOL(gss_subflavor_to_mech);

void
kgss_mech_put(struct gss_api_mech *gm)
{
        module_put(gm->gm_owner);
}

//EXPORT_SYMBOL(kgss_mech_put);

/* The mech could probably be determined from the token instead, but it's just
 * as easy for now to pass it in. */
__u32
kgss_import_sec_context(rawobj_t                *input_token,
                        struct gss_api_mech     *mech,
                        struct gss_ctx         **ctx_id)
{
        OBD_ALLOC(*ctx_id, sizeof(**ctx_id));
        if (*ctx_id == NULL)
                return GSS_S_FAILURE;

        (*ctx_id)->mech_type = kgss_mech_get(mech);

        LASSERT(mech);
        LASSERT(mech->gm_ops);
        LASSERT(mech->gm_ops->gss_import_sec_context);
        return mech->gm_ops->gss_import_sec_context(input_token, *ctx_id);
}

/*
 * this interface is much simplified, currently we only need endtime.
 */
__u32
kgss_inquire_context(struct gss_ctx    *context_handle,
                     __u64             *endtime)
{
        LASSERT(context_handle);
        LASSERT(context_handle->mech_type);
        LASSERT(context_handle->mech_type->gm_ops);
        LASSERT(context_handle->mech_type->gm_ops->gss_inquire_context);

        return context_handle->mech_type->gm_ops
                ->gss_inquire_context(context_handle,
                                      endtime);
}

/* gss_get_mic: compute a mic over message and return mic_token. */
__u32
kgss_get_mic(struct gss_ctx     *context_handle,
             __u32               qop,
             rawobj_t           *message,
             rawobj_t           *mic_token)
{
        LASSERT(context_handle);
        LASSERT(context_handle->mech_type);
        LASSERT(context_handle->mech_type->gm_ops);
        LASSERT(context_handle->mech_type->gm_ops->gss_get_mic);

        return context_handle->mech_type->gm_ops
                ->gss_get_mic(context_handle,
                              qop,
                              message,
                              mic_token);
}

/* gss_verify_mic: check whether the provided mic_token verifies message. */
__u32
kgss_verify_mic(struct gss_ctx  *context_handle,
                rawobj_t        *message,
                rawobj_t        *mic_token,
                __u32           *qstate)
{
        LASSERT(context_handle);
        LASSERT(context_handle->mech_type);
        LASSERT(context_handle->mech_type->gm_ops);
        LASSERT(context_handle->mech_type->gm_ops->gss_verify_mic);

        return context_handle->mech_type->gm_ops
                ->gss_verify_mic(context_handle,
                                 message,
                                 mic_token,
                                 qstate);
}

__u32
kgss_wrap(struct gss_ctx        *context_handle,
          __u32                  qop,
          rawobj_buf_t          *inbuf,
          rawobj_t              *outbuf)
{
        LASSERT(context_handle);
        LASSERT(context_handle->mech_type);
        LASSERT(context_handle->mech_type->gm_ops);
        LASSERT(context_handle->mech_type->gm_ops->gss_wrap);

        return context_handle->mech_type->gm_ops
                ->gss_wrap(context_handle, qop, inbuf, outbuf);
}

__u32
kgss_unwrap(struct gss_ctx        *context_handle,
            __u32                  qop,
            rawobj_t              *inbuf,
            rawobj_t              *outbuf)
{
        LASSERT(context_handle);
        LASSERT(context_handle->mech_type);
        LASSERT(context_handle->mech_type->gm_ops);
        LASSERT(context_handle->mech_type->gm_ops->gss_unwrap);

        return context_handle->mech_type->gm_ops
                ->gss_unwrap(context_handle, qop, inbuf, outbuf);
}


/* gss_delete_sec_context: free all resources associated with context_handle.
 * Note this differs from the RFC 2744-specified prototype in that we don't
 * bother returning an output token, since it would never be used anyway. */

__u32
kgss_delete_sec_context(struct gss_ctx  **context_handle)
{
        struct gss_api_mech *mech;

        CDEBUG(D_SEC, "deleting %p\n", *context_handle);

        if (!*context_handle)
                return(GSS_S_NO_CONTEXT);

        mech = (*context_handle)->mech_type;
        if ((*context_handle)->internal_ctx_id != 0) {
                LASSERT(mech);
                LASSERT(mech->gm_ops);
                LASSERT(mech->gm_ops->gss_delete_sec_context);
                mech->gm_ops->gss_delete_sec_context(
                                        (*context_handle)->internal_ctx_id);
        }
        if (mech)
                kgss_mech_put(mech);

        OBD_FREE(*context_handle, sizeof(**context_handle));
        *context_handle=NULL;
        return GSS_S_COMPLETE;
}