/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ptlrpc/sec_bulk.c
 *
 * Author: Eric Mei <ericm@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_SEC

#include "../../include/linux/libcfs/libcfs.h"

#include "../include/obd.h"
#include "../include/obd_cksum.h"
#include "../include/obd_class.h"
#include "../include/obd_support.h"
#include "../include/lustre_net.h"
#include "../include/lustre_import.h"
#include "../include/lustre_dlm.h"
#include "../include/lustre_sec.h"

#include "ptlrpc_internal.h"

/****************************************
 * bulk encryption page pools      *
 ****************************************/

#define POINTERS_PER_PAGE       (PAGE_SIZE / sizeof(void *))
#define PAGES_PER_POOL          (POINTERS_PER_PAGE)

#define IDLE_IDX_MAX     (100)
#define IDLE_IDX_WEIGHT  (3)

#define CACHE_QUIESCENT_PERIOD  (20)

static struct ptlrpc_enc_page_pool {
        /*
         * constants
         */
        unsigned long    epp_max_pages;   /* maximum pages can hold, const */
        unsigned int     epp_max_pools;   /* number of pools, const */

        /*
         * wait queue in case of not enough free pages.
         */
        wait_queue_head_t      epp_waitq;       /* waiting threads */
        unsigned int     epp_waitqlen;    /* wait queue length */
        unsigned long    epp_pages_short; /* # of pages wanted of in-q users */
        unsigned int     epp_growing:1;   /* during adding pages */

        /*
         * indicating how idle the pools are, from 0 to MAX_IDLE_IDX
         * this is counted based on each time when getting pages from
         * the pools, not based on time. which means in case that system
         * is idled for a while but the idle_idx might still be low if no
         * activities happened in the pools.
         */
        unsigned long    epp_idle_idx;

        /* last shrink time due to mem tight */
        time64_t         epp_last_shrink;
        time64_t         epp_last_access;

        /*
         * in-pool pages bookkeeping
         */
        spinlock_t       epp_lock;         /* protect following fields */
        unsigned long    epp_total_pages; /* total pages in pools */
        unsigned long    epp_free_pages;  /* current pages available */

        /*
         * statistics
         */
        unsigned long    epp_st_max_pages;      /* # of pages ever reached */
        unsigned int     epp_st_grows;    /* # of grows */
        unsigned int     epp_st_grow_fails;     /* # of add pages failures */
        unsigned int     epp_st_shrinks;        /* # of shrinks */
        unsigned long    epp_st_access;  /* # of access */
        unsigned long    epp_st_missings;       /* # of cache missing */
        unsigned long    epp_st_lowfree;        /* lowest free pages reached */
        unsigned int     epp_st_max_wqlen;      /* highest waitqueue length */
        unsigned long       epp_st_max_wait;       /* in jiffies */
        unsigned long    epp_st_outofmem;       /* # of out of mem requests */
        /*
         * pointers to pools
         */
        struct page    ***epp_pools;
} page_pools;

/*
 * /sys/kernel/debug/lustre/sptlrpc/encrypt_page_pools
 */
int sptlrpc_proc_enc_pool_seq_show(struct seq_file *m, void *v)
{
        spin_lock(&page_pools.epp_lock);

        seq_printf(m,
                   "physical pages:       %lu\n"
                   "pages per pool:       %lu\n"
                   "max pages:         %lu\n"
                   "max pools:         %u\n"
                   "total pages:             %lu\n"
                   "total free:       %lu\n"
                   "idle index:       %lu/100\n"
                   "last shrink:             %lds\n"
                   "last access:             %lds\n"
                   "max pages reached:       %lu\n"
                   "grows:                 %u\n"
                   "grows failure:         %u\n"
                   "shrinks:             %u\n"
                   "cache access:           %lu\n"
                   "cache missing:         %lu\n"
                   "low free mark:         %lu\n"
                   "max waitqueue depth:     %u\n"
                   "max wait time:         %ld/%lu\n"
                   "out of mem:          %lu\n",
                   totalram_pages,
                   PAGES_PER_POOL,
                   page_pools.epp_max_pages,
                   page_pools.epp_max_pools,
                   page_pools.epp_total_pages,
                   page_pools.epp_free_pages,
                   page_pools.epp_idle_idx,
                   (long)(ktime_get_seconds() - page_pools.epp_last_shrink),
                   (long)(ktime_get_seconds() - page_pools.epp_last_access),
                   page_pools.epp_st_max_pages,
                   page_pools.epp_st_grows,
                   page_pools.epp_st_grow_fails,
                   page_pools.epp_st_shrinks,
                   page_pools.epp_st_access,
                   page_pools.epp_st_missings,
                   page_pools.epp_st_lowfree,
                   page_pools.epp_st_max_wqlen,
                   page_pools.epp_st_max_wait,
                   msecs_to_jiffies(MSEC_PER_SEC),
                   page_pools.epp_st_outofmem);

        spin_unlock(&page_pools.epp_lock);

        return 0;
}

static void enc_pools_release_free_pages(long npages)
{
        int p_idx, g_idx;
        int p_idx_max1, p_idx_max2;

        LASSERT(npages > 0);
        LASSERT(npages <= page_pools.epp_free_pages);
        LASSERT(page_pools.epp_free_pages <= page_pools.epp_total_pages);

        /* max pool index before the release */
        p_idx_max2 = (page_pools.epp_total_pages - 1) / PAGES_PER_POOL;

        page_pools.epp_free_pages -= npages;
        page_pools.epp_total_pages -= npages;

        /* max pool index after the release */
        p_idx_max1 = page_pools.epp_total_pages == 0 ? -1 :
                     ((page_pools.epp_total_pages - 1) / PAGES_PER_POOL);

        p_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        g_idx = page_pools.epp_free_pages % PAGES_PER_POOL;
        LASSERT(page_pools.epp_pools[p_idx]);

        while (npages--) {
                LASSERT(page_pools.epp_pools[p_idx]);
                LASSERT(page_pools.epp_pools[p_idx][g_idx]);

                __free_page(page_pools.epp_pools[p_idx][g_idx]);
                page_pools.epp_pools[p_idx][g_idx] = NULL;

                if (++g_idx == PAGES_PER_POOL) {
                        p_idx++;
                        g_idx = 0;
                }
        }

        /* free unused pools */
        while (p_idx_max1 < p_idx_max2) {
                LASSERT(page_pools.epp_pools[p_idx_max2]);
                kfree(page_pools.epp_pools[p_idx_max2]);
                page_pools.epp_pools[p_idx_max2] = NULL;
                p_idx_max2--;
        }
}

/*
 * we try to keep at least PTLRPC_MAX_BRW_PAGES pages in the pool.
 */
static unsigned long enc_pools_shrink_count(struct shrinker *s,
                                            struct shrink_control *sc)
{
        /*
         * if no pool access for a long time, we consider it's fully idle.
         * a little race here is fine.
         */
        if (unlikely(ktime_get_seconds() - page_pools.epp_last_access >
                     CACHE_QUIESCENT_PERIOD)) {
                spin_lock(&page_pools.epp_lock);
                page_pools.epp_idle_idx = IDLE_IDX_MAX;
                spin_unlock(&page_pools.epp_lock);
        }

        LASSERT(page_pools.epp_idle_idx <= IDLE_IDX_MAX);
        return max((int)page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES, 0) *
                (IDLE_IDX_MAX - page_pools.epp_idle_idx) / IDLE_IDX_MAX;
}

/*
 * we try to keep at least PTLRPC_MAX_BRW_PAGES pages in the pool.
 */
static unsigned long enc_pools_shrink_scan(struct shrinker *s,
                                           struct shrink_control *sc)
{
        spin_lock(&page_pools.epp_lock);
        sc->nr_to_scan = min_t(unsigned long, sc->nr_to_scan,
                              page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES);
        if (sc->nr_to_scan > 0) {
                enc_pools_release_free_pages(sc->nr_to_scan);
                CDEBUG(D_SEC, "released %ld pages, %ld left\n",
                       (long)sc->nr_to_scan, page_pools.epp_free_pages);

                page_pools.epp_st_shrinks++;
                page_pools.epp_last_shrink = ktime_get_seconds();
        }
        spin_unlock(&page_pools.epp_lock);

        /*
         * if no pool access for a long time, we consider it's fully idle.
         * a little race here is fine.
         */
        if (unlikely(ktime_get_seconds() - page_pools.epp_last_access >
                     CACHE_QUIESCENT_PERIOD)) {
                spin_lock(&page_pools.epp_lock);
                page_pools.epp_idle_idx = IDLE_IDX_MAX;
                spin_unlock(&page_pools.epp_lock);
        }

        LASSERT(page_pools.epp_idle_idx <= IDLE_IDX_MAX);
        return sc->nr_to_scan;
}

static inline
int npages_to_npools(unsigned long npages)
{
        return (int)DIV_ROUND_UP(npages, PAGES_PER_POOL);
}

/*
 * return how many pages cleaned up.
 */
static unsigned long enc_pools_cleanup(struct page ***pools, int npools)
{
        unsigned long cleaned = 0;
        int i, j;

        for (i = 0; i < npools; i++) {
                if (pools[i]) {
                        for (j = 0; j < PAGES_PER_POOL; j++) {
                                if (pools[i][j]) {
                                        __free_page(pools[i][j]);
                                        cleaned++;
                                }
                        }
                        kfree(pools[i]);
                        pools[i] = NULL;
                }
        }

        return cleaned;
}

static inline void enc_pools_wakeup(void)
{
        assert_spin_locked(&page_pools.epp_lock);

        if (unlikely(page_pools.epp_waitqlen)) {
                LASSERT(waitqueue_active(&page_pools.epp_waitq));
                wake_up_all(&page_pools.epp_waitq);
        }
}

/*
 * Export the number of free pages in the pool
 */
int get_free_pages_in_pool(void)
{
        return page_pools.epp_free_pages;
}

/*
 * Let outside world know if enc_pool full capacity is reached
 */
int pool_is_at_full_capacity(void)
{
        return (page_pools.epp_total_pages == page_pools.epp_max_pages);
}

void sptlrpc_enc_pool_put_pages(struct ptlrpc_bulk_desc *desc)
{
        int p_idx, g_idx;
        int i;

        LASSERT(ptlrpc_is_bulk_desc_kiov(desc->bd_type));

        if (!GET_ENC_KIOV(desc))
                return;

        LASSERT(desc->bd_iov_count > 0);

        spin_lock(&page_pools.epp_lock);

        p_idx = page_pools.epp_free_pages / PAGES_PER_POOL;
        g_idx = page_pools.epp_free_pages % PAGES_PER_POOL;

        LASSERT(page_pools.epp_free_pages + desc->bd_iov_count <=
                page_pools.epp_total_pages);
        LASSERT(page_pools.epp_pools[p_idx]);

        for (i = 0; i < desc->bd_iov_count; i++) {
                LASSERT(BD_GET_ENC_KIOV(desc, i).bv_page);
                LASSERT(g_idx != 0 || page_pools.epp_pools[p_idx]);
                LASSERT(!page_pools.epp_pools[p_idx][g_idx]);

                page_pools.epp_pools[p_idx][g_idx] =
                        BD_GET_ENC_KIOV(desc, i).bv_page;

                if (++g_idx == PAGES_PER_POOL) {
                        p_idx++;
                        g_idx = 0;
                }
        }

        page_pools.epp_free_pages += desc->bd_iov_count;

        enc_pools_wakeup();

        spin_unlock(&page_pools.epp_lock);

        kfree(GET_ENC_KIOV(desc));
        GET_ENC_KIOV(desc) = NULL;
}

static inline void enc_pools_alloc(void)
{
        LASSERT(page_pools.epp_max_pools);
        page_pools.epp_pools =
                libcfs_kvzalloc(page_pools.epp_max_pools *
                                sizeof(*page_pools.epp_pools),
                                GFP_NOFS);
}

static inline void enc_pools_free(void)
{
        LASSERT(page_pools.epp_max_pools);
        LASSERT(page_pools.epp_pools);

        kvfree(page_pools.epp_pools);
}

static struct shrinker pools_shrinker = {
        .count_objects  = enc_pools_shrink_count,
        .scan_objects   = enc_pools_shrink_scan,
        .seeks          = DEFAULT_SEEKS,
};

int sptlrpc_enc_pool_init(void)
{
        /*
         * maximum capacity is 1/8 of total physical memory.
         * is the 1/8 a good number?
         */
        page_pools.epp_max_pages = totalram_pages / 8;
        page_pools.epp_max_pools = npages_to_npools(page_pools.epp_max_pages);

        init_waitqueue_head(&page_pools.epp_waitq);
        page_pools.epp_waitqlen = 0;
        page_pools.epp_pages_short = 0;

        page_pools.epp_growing = 0;

        page_pools.epp_idle_idx = 0;
        page_pools.epp_last_shrink = ktime_get_seconds();
        page_pools.epp_last_access = ktime_get_seconds();

        spin_lock_init(&page_pools.epp_lock);
        page_pools.epp_total_pages = 0;
        page_pools.epp_free_pages = 0;

        page_pools.epp_st_max_pages = 0;
        page_pools.epp_st_grows = 0;
        page_pools.epp_st_grow_fails = 0;
        page_pools.epp_st_shrinks = 0;
        page_pools.epp_st_access = 0;
        page_pools.epp_st_missings = 0;
        page_pools.epp_st_lowfree = 0;
        page_pools.epp_st_max_wqlen = 0;
        page_pools.epp_st_max_wait = 0;
        page_pools.epp_st_outofmem = 0;

        enc_pools_alloc();
        if (!page_pools.epp_pools)
                return -ENOMEM;

        register_shrinker(&pools_shrinker);

        return 0;
}

void sptlrpc_enc_pool_fini(void)
{
        unsigned long cleaned, npools;

        LASSERT(page_pools.epp_pools);
        LASSERT(page_pools.epp_total_pages == page_pools.epp_free_pages);

        unregister_shrinker(&pools_shrinker);

        npools = npages_to_npools(page_pools.epp_total_pages);
        cleaned = enc_pools_cleanup(page_pools.epp_pools, npools);
        LASSERT(cleaned == page_pools.epp_total_pages);

        enc_pools_free();

        if (page_pools.epp_st_access > 0) {
                CDEBUG(D_SEC,
                       "max pages %lu, grows %u, grow fails %u, shrinks %u, access %lu, missing %lu, max qlen %u, max wait %ld/%ld, out of mem %lu\n",
                       page_pools.epp_st_max_pages, page_pools.epp_st_grows,
                       page_pools.epp_st_grow_fails,
                       page_pools.epp_st_shrinks, page_pools.epp_st_access,
                       page_pools.epp_st_missings, page_pools.epp_st_max_wqlen,
                       page_pools.epp_st_max_wait,
                       msecs_to_jiffies(MSEC_PER_SEC),
                       page_pools.epp_st_outofmem);
        }
}

static int cfs_hash_alg_id[] = {
        [BULK_HASH_ALG_NULL]    = CFS_HASH_ALG_NULL,
        [BULK_HASH_ALG_ADLER32] = CFS_HASH_ALG_ADLER32,
        [BULK_HASH_ALG_CRC32]   = CFS_HASH_ALG_CRC32,
        [BULK_HASH_ALG_MD5]     = CFS_HASH_ALG_MD5,
        [BULK_HASH_ALG_SHA1]    = CFS_HASH_ALG_SHA1,
        [BULK_HASH_ALG_SHA256]  = CFS_HASH_ALG_SHA256,
        [BULK_HASH_ALG_SHA384]  = CFS_HASH_ALG_SHA384,
        [BULK_HASH_ALG_SHA512]  = CFS_HASH_ALG_SHA512,
};

const char *sptlrpc_get_hash_name(__u8 hash_alg)
{
        return cfs_crypto_hash_name(cfs_hash_alg_id[hash_alg]);
}

__u8 sptlrpc_get_hash_alg(const char *algname)
{
        return cfs_crypto_hash_alg(algname);
}

int bulk_sec_desc_unpack(struct lustre_msg *msg, int offset, int swabbed)
{
        struct ptlrpc_bulk_sec_desc *bsd;
        int                       size = msg->lm_buflens[offset];

        bsd = lustre_msg_buf(msg, offset, sizeof(*bsd));
        if (!bsd) {
                CERROR("Invalid bulk sec desc: size %d\n", size);
                return -EINVAL;
        }

        if (swabbed)
                __swab32s(&bsd->bsd_nob);

        if (unlikely(bsd->bsd_version != 0)) {
                CERROR("Unexpected version %u\n", bsd->bsd_version);
                return -EPROTO;
        }

        if (unlikely(bsd->bsd_type >= SPTLRPC_BULK_MAX)) {
                CERROR("Invalid type %u\n", bsd->bsd_type);
                return -EPROTO;
        }

        /* FIXME more sanity check here */

        if (unlikely(bsd->bsd_svc != SPTLRPC_BULK_SVC_NULL &&
                     bsd->bsd_svc != SPTLRPC_BULK_SVC_INTG &&
                     bsd->bsd_svc != SPTLRPC_BULK_SVC_PRIV)) {
                CERROR("Invalid svc %u\n", bsd->bsd_svc);
                return -EPROTO;
        }

        return 0;
}
EXPORT_SYMBOL(bulk_sec_desc_unpack);

int sptlrpc_get_bulk_checksum(struct ptlrpc_bulk_desc *desc, __u8 alg,
                              void *buf, int buflen)
{
        struct cfs_crypto_hash_desc *hdesc;
        int hashsize;
        unsigned int bufsize;
        int i, err;

        LASSERT(alg > BULK_HASH_ALG_NULL && alg < BULK_HASH_ALG_MAX);
        LASSERT(buflen >= 4);

        hdesc = cfs_crypto_hash_init(cfs_hash_alg_id[alg], NULL, 0);
        if (IS_ERR(hdesc)) {
                CERROR("Unable to initialize checksum hash %s\n",
                       cfs_crypto_hash_name(cfs_hash_alg_id[alg]));
                return PTR_ERR(hdesc);
        }

        hashsize = cfs_crypto_hash_digestsize(cfs_hash_alg_id[alg]);

        for (i = 0; i < desc->bd_iov_count; i++) {
                cfs_crypto_hash_update_page(hdesc,
                                            BD_GET_KIOV(desc, i).bv_page,
                                            BD_GET_KIOV(desc, i).bv_offset &
                                            ~PAGE_MASK,
                                            BD_GET_KIOV(desc, i).bv_len);
        }

        if (hashsize > buflen) {
                unsigned char hashbuf[CFS_CRYPTO_HASH_DIGESTSIZE_MAX];

                bufsize = sizeof(hashbuf);
                LASSERTF(bufsize >= hashsize, "bufsize = %u < hashsize %u\n",
                         bufsize, hashsize);
                err = cfs_crypto_hash_final(hdesc, hashbuf, &bufsize);
                memcpy(buf, hashbuf, buflen);
        } else {
                bufsize = buflen;
                err = cfs_crypto_hash_final(hdesc, buf, &bufsize);
        }

        return err;
}