inet/ilb/ilb_alg_hash.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/cmn_err.h>
#include <netinet/in.h>
#include <inet/ip.h>
#include <inet/ip6.h>
#include <sys/crc32.h>

#include <inet/ilb.h>
#include "ilb_impl.h"
#include "ilb_alg.h"

#define HASH_IP_V4(hash, addr, size)                    \
{                                   \
    CRC32((hash), &(addr), sizeof (in_addr_t), -1U, crc32_table);   \
    (hash) %= (size);                       \
}
#define HASH_IP_V6(hash, addr, size)                    \
    HASH_IP_V4((hash), (addr)->s6_addr32[3], (size))

#define HASH_IP_PORT_V4(hash, addr, port, size)             \
{                                   \
    uint32_t val = (addr) ^ ((port) << 16) ^ (port);        \
    CRC32((hash), &val, sizeof (uint32_t), -1U, crc32_table);   \
    (hash) %= (size);                       \
}
#define HASH_IP_PORT_V6(hash, addr, port, size)             \
    HASH_IP_PORT_V4((hash), (addr)->s6_addr32[3], (port), (size))

#define HASH_IP_VIP_V4(hash, saddr, daddr, size)            \
{                                   \
    uint32_t val = (saddr) ^ (daddr);               \
    CRC32((hash), &val, sizeof (uint32_t), -1U, crc32_table);   \
    (hash) %= (size);                       \
}
#define HASH_IP_VIP_V6(hash, saddr, daddr, size)            \
    HASH_IP_VIP_V4((hash), (saddr)->s6_addr32[3], (daddr)->s6_addr32[3], \
    (size))

#define INIT_HASH_TBL_SIZE  10

typedef struct {
    ilb_server_t    *server;
    boolean_t   enabled;
} hash_server_t;

/*
 * There are two hash tables.  The hash_tbl holds all servers, both enabled
 * and disabled.  The hash_enabled_tbl only holds enabled servers.  Having
 * two tables allows the hash on a client request remains the same even when
 * some servers are disabled.  If a server is disabled and a client's request
 * hashes to it, we will do another hash.  This time the has is on the enabled
 * server table.
 */
typedef struct hash_s {
    kmutex_t    hash_lock;
    size_t      hash_servers;       /* Total # of servers */
    size_t      hash_tbl_size;      /* All server table size */
    size_t      hash_enabled_servers;   /* # of enabled servers */
    size_t      hash_enabled_tbl_size;  /* Enabled server table size */
    hash_server_t   *hash_tbl;
    hash_server_t   *hash_enabled_tbl;
    ilb_algo_impl_t hash_type;
} hash_t;

static void hash_fini(ilb_alg_data_t **);

/* ARGSUSED */
static boolean_t
hash_lb(in6_addr_t *saddr, in_port_t sport, in6_addr_t *daddr,
    in_port_t dport, void *alg_data, ilb_server_t **ret_server)
{
    hash_t *hash_alg = (hash_t *)alg_data;
    uint32_t i;

    ASSERT(ret_server != NULL);
    *ret_server = NULL;

    mutex_enter(&hash_alg->hash_lock);

    if (hash_alg->hash_servers == 0) {
        mutex_exit(&hash_alg->hash_lock);
        return (B_FALSE);
    }

    switch (hash_alg->hash_type) {
    case ILB_ALG_IMPL_HASH_IP:
        HASH_IP_V6(i, saddr, hash_alg->hash_servers);
        break;
    case ILB_ALG_IMPL_HASH_IP_SPORT:
        HASH_IP_PORT_V6(i, saddr, sport, hash_alg->hash_servers);
        break;
    case ILB_ALG_IMPL_HASH_IP_VIP:
        HASH_IP_VIP_V6(i, saddr, daddr, hash_alg->hash_servers);
        break;
    default:
        mutex_exit(&hash_alg->hash_lock);
        return (B_FALSE);
    }
    if (hash_alg->hash_tbl[i].enabled) {
        *ret_server = hash_alg->hash_tbl[i].server;
        mutex_exit(&hash_alg->hash_lock);
        return (B_TRUE);
    }

    if (hash_alg->hash_enabled_servers == 0) {
        mutex_exit(&hash_alg->hash_lock);
        return (B_FALSE);
    }

    switch (hash_alg->hash_type) {
    case ILB_ALG_IMPL_HASH_IP:
        HASH_IP_V6(i, saddr, hash_alg->hash_enabled_servers);
        break;
    case ILB_ALG_IMPL_HASH_IP_SPORT:
        HASH_IP_PORT_V6(i, saddr, sport,
            hash_alg->hash_enabled_servers);
        break;
    case ILB_ALG_IMPL_HASH_IP_VIP:
        HASH_IP_VIP_V6(i, saddr, daddr,
            hash_alg->hash_enabled_servers);
        break;
    default:
        ASSERT(0);
        break;
    }
    *ret_server = hash_alg->hash_enabled_tbl[i].server;
    mutex_exit(&hash_alg->hash_lock);
    return (B_TRUE);
}

static boolean_t
del_server(hash_server_t *tbl, size_t hash_size, ilb_server_t *host)
{
    size_t i, j;

    for (i = 0; i < hash_size; i++) {
        if (tbl[i].server == host) {
            if (i == hash_size - 1)
                break;
            for (j = i; j < hash_size - 1; j++)
                tbl[j] = tbl[j + 1];
            break;
        }
    }
    /* Not found... */
    if (i == hash_size)
        return (B_FALSE);
    tbl[hash_size - 1].server = NULL;
    tbl[hash_size - 1].enabled = B_FALSE;
    return (B_TRUE);
}

static int
hash_server_del(ilb_server_t *host, void *alg_data)
{
    hash_t *hash_alg = (hash_t *)alg_data;
    boolean_t ret;

    mutex_enter(&hash_alg->hash_lock);

    ret = del_server(hash_alg->hash_tbl, hash_alg->hash_servers, host);
    if (!ret) {
        mutex_exit(&hash_alg->hash_lock);
        return (EINVAL);
    }
    hash_alg->hash_servers--;

    /* The server may not be enabled. */
    ret = del_server(hash_alg->hash_enabled_tbl,
        hash_alg->hash_enabled_servers, host);
    if (ret)
        hash_alg->hash_enabled_servers--;

    mutex_exit(&hash_alg->hash_lock);
    ILB_SERVER_REFRELE(host);
    return (0);
}

static int
grow_tbl(hash_server_t **hash_tbl, size_t *tbl_size)
{
    size_t mem_size;
    hash_server_t *new_tbl;

    if ((new_tbl = kmem_zalloc(sizeof (hash_server_t) *
        (*tbl_size + INIT_HASH_TBL_SIZE), KM_NOSLEEP)) == NULL) {
        return (ENOMEM);
    }
    mem_size = *tbl_size * sizeof (hash_server_t);
    bcopy(*hash_tbl, new_tbl, mem_size);
    kmem_free(*hash_tbl, mem_size);
    *hash_tbl = new_tbl;
    *tbl_size += INIT_HASH_TBL_SIZE;
    return (0);
}

static int
hash_server_add(ilb_server_t *host, void *alg_data)
{
    hash_t *hash_alg = (hash_t *)alg_data;
    size_t new_size;

    mutex_enter(&hash_alg->hash_lock);

    /* First add the server to the hash_tbl. */
    new_size = hash_alg->hash_servers + 1;
    if (new_size > hash_alg->hash_tbl_size) {
        if (grow_tbl(&hash_alg->hash_tbl, &hash_alg->hash_tbl_size) !=
            0) {
            mutex_exit(&hash_alg->hash_lock);
            return (ENOMEM);
        }
    }

    hash_alg->hash_tbl[hash_alg->hash_servers].server = host;
    hash_alg->hash_tbl[hash_alg->hash_servers].enabled = host->iser_enabled;
    hash_alg->hash_servers++;

    if (!host->iser_enabled) {
        mutex_exit(&hash_alg->hash_lock);
        ILB_SERVER_REFHOLD(host);
        return (0);
    }

    /* If the server is enabled, add it to the hasn_enabled_tbl. */
    new_size = hash_alg->hash_enabled_servers + 1;
    if (new_size > hash_alg->hash_enabled_tbl_size) {
        if (grow_tbl(&hash_alg->hash_enabled_tbl,
            &hash_alg->hash_enabled_tbl_size) != 0) {
            mutex_exit(&hash_alg->hash_lock);
            return (ENOMEM);
        }
    }
    hash_alg->hash_enabled_tbl[hash_alg->hash_enabled_servers].server =
        host;
    hash_alg->hash_enabled_tbl[hash_alg->hash_enabled_servers].enabled =
        B_TRUE;
    hash_alg->hash_enabled_servers++;

    mutex_exit(&hash_alg->hash_lock);
    ILB_SERVER_REFHOLD(host);
    return (0);
}

static int
hash_server_enable(ilb_server_t *host, void *alg_data)
{
    hash_t *alg = (hash_t *)alg_data;
    size_t new_size, i;

    mutex_enter(&alg->hash_lock);

    for (i = 0; i < alg->hash_servers; i++) {
        if (alg->hash_tbl[i].server == host) {
            if (alg->hash_tbl[i].enabled) {
                mutex_exit(&alg->hash_lock);
                return (0);
            } else {
                break;
            }
        }
    }
    if (i == alg->hash_servers) {
        mutex_exit(&alg->hash_lock);
        return (EINVAL);
    }

#if DEBUG
    /* The server should not be in the enabled tabled. */
    {
        size_t j;

        for (j = 0; j < alg->hash_enabled_servers; j++) {
            if (alg->hash_enabled_tbl[j].server == host) {
                cmn_err(CE_PANIC, "Corrupted ILB enabled hash "
                    "table");
            }
        }
    }
#endif

    new_size = alg->hash_enabled_servers + 1;
    if (new_size > alg->hash_enabled_tbl_size) {
        if (grow_tbl(&alg->hash_enabled_tbl,
            &alg->hash_enabled_tbl_size) != 0) {
            mutex_exit(&alg->hash_lock);
            return (ENOMEM);
        }
    }
    alg->hash_tbl[i].enabled = B_TRUE;
    alg->hash_enabled_tbl[alg->hash_enabled_servers].server = host;
    alg->hash_enabled_tbl[alg->hash_enabled_servers].enabled = B_TRUE;
    alg->hash_enabled_servers++;

    mutex_exit(&alg->hash_lock);
    return (0);
}

static int
hash_server_disable(ilb_server_t *host, void *alg_data)
{
    hash_t *alg = (hash_t *)alg_data;
    size_t i;

    mutex_enter(&alg->hash_lock);

    for (i = 0; i < alg->hash_servers; i++) {
        if (alg->hash_tbl[i].server == host) {
            if (!alg->hash_tbl[i].enabled) {
                mutex_exit(&alg->hash_lock);
                return (0);
            } else {
                break;
            }
        }
    }
    if (i == alg->hash_servers) {
        mutex_exit(&alg->hash_lock);
        return (EINVAL);
    }

    alg->hash_tbl[i].enabled = B_FALSE;
#if DEBUG
    ASSERT(del_server(alg->hash_enabled_tbl, alg->hash_enabled_servers,
        host));
#else
    (void) del_server(alg->hash_enabled_tbl, alg->hash_enabled_servers,
        host);
#endif
    alg->hash_enabled_servers--;

    mutex_exit(&alg->hash_lock);
    return (0);
}

/* ARGSUSED */
ilb_alg_data_t *
ilb_alg_hash_init(ilb_rule_t *rule, const void *arg)
{
    ilb_alg_data_t  *alg;
    hash_t      *hash_alg;
    int     flags = *(int *)arg;

    if ((alg = kmem_alloc(sizeof (ilb_alg_data_t), KM_NOSLEEP)) == NULL)
        return (NULL);
    if ((hash_alg = kmem_alloc(sizeof (hash_t), KM_NOSLEEP)) == NULL) {
        kmem_free(alg, sizeof (ilb_alg_data_t));
        return (NULL);
    }
    alg->ilb_alg_lb = hash_lb;
    alg->ilb_alg_server_del = hash_server_del;
    alg->ilb_alg_server_add = hash_server_add;
    alg->ilb_alg_server_enable = hash_server_enable;
    alg->ilb_alg_server_disable = hash_server_disable;
    alg->ilb_alg_fini = hash_fini;
    alg->ilb_alg_data = hash_alg;

    mutex_init(&hash_alg->hash_lock, NULL, MUTEX_DEFAULT, NULL);
    hash_alg->hash_type = flags;

    /* Table of all servers */
    hash_alg->hash_servers = 0;
    hash_alg->hash_tbl_size = INIT_HASH_TBL_SIZE;
    hash_alg->hash_tbl = kmem_zalloc(sizeof (hash_server_t) *
        INIT_HASH_TBL_SIZE, KM_NOSLEEP);
    if (hash_alg->hash_tbl == NULL) {
        kmem_free(hash_alg, sizeof (hash_t));
        kmem_free(alg, sizeof (ilb_alg_data_t));
        return (NULL);
    }

    /* Table of only enabled servers */
    hash_alg->hash_enabled_servers = 0;
    hash_alg->hash_enabled_tbl_size = INIT_HASH_TBL_SIZE;
    hash_alg->hash_enabled_tbl = kmem_zalloc(sizeof (hash_server_t) *
        INIT_HASH_TBL_SIZE, KM_NOSLEEP);
    if (hash_alg->hash_tbl == NULL) {
        kmem_free(hash_alg->hash_tbl, INIT_HASH_TBL_SIZE *
            sizeof (ilb_server_t *));
        kmem_free(hash_alg, sizeof (hash_t));
        kmem_free(alg, sizeof (ilb_alg_data_t));
        return (NULL);
    }

    return (alg);
}

static void
hash_fini(ilb_alg_data_t **alg)
{
    hash_t      *hash_alg;
    int     i;

    hash_alg = (*alg)->ilb_alg_data;
    for (i = 0; i < hash_alg->hash_servers; i++)
        ILB_SERVER_REFRELE(hash_alg->hash_tbl[i].server);

    kmem_free(hash_alg->hash_tbl, sizeof (hash_server_t) *
        hash_alg->hash_tbl_size);
    kmem_free(hash_alg->hash_enabled_tbl, sizeof (hash_server_t) *
        hash_alg->hash_enabled_tbl_size);
    kmem_free(hash_alg, sizeof (hash_t));
    kmem_free(*alg, sizeof (ilb_alg_data_t));
    *alg = NULL;
}