/*-
 * Copyright (c) 2004-2005 Sam Leffler, Errno Consulting
 * All rights reserved.
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#ifdef __FreeBSD__
__FBSDID("$FreeBSD: src/sys/net80211/ieee80211_acl.c,v 1.4 2005/08/13 17:31:48 sam Exp $");
#endif
#ifdef __NetBSD__
__KERNEL_RCSID(0, "$NetBSD: ieee80211_acl.c,v 1.10 2019/11/10 21:16:38 chs Exp $");
#endif

/*
 * IEEE 802.11 MAC ACL support.
 *
 * When this module is loaded the sender address of each received
 * frame is passed to the iac_check method and the module indicates
 * if the frame should be accepted or rejected.  If the policy is
 * set to ACL_POLICY_OPEN then all frames are accepted w/o checking
 * the address.  Otherwise, the address is looked up in the database
 * and if found the frame is either accepted (ACL_POLICY_ALLOW)
 * or rejected (ACL_POLICY_DENT).
 */
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h> 
#include <sys/mbuf.h>   
#include <sys/queue.h>

#include <sys/socket.h>

#include <net/if.h>
#include <net/if_media.h>
#include <net/if_ether.h>
#include <net/route.h>

#include <net80211/ieee80211_var.h>

enum {
        ACL_POLICY_OPEN         = 0,    /* open, don't check ACL's */
        ACL_POLICY_ALLOW        = 1,    /* allow traffic from MAC */
        ACL_POLICY_DENY         = 2,    /* deny traffic from MAC */
};

#define ACL_HASHSIZE    32

struct acl {
        TAILQ_ENTRY(acl)        acl_list;
        LIST_ENTRY(acl)         acl_hash;
        u_int8_t                acl_macaddr[IEEE80211_ADDR_LEN];
};
struct aclstate {
        acl_lock_t              as_lock;
        int                     as_policy;
        uint32_t                as_nacls;
        TAILQ_HEAD(, acl)       as_list;        /* list of all ACL's */
        LIST_HEAD(, acl)        as_hash[ACL_HASHSIZE];
        struct ieee80211com     *as_ic;
};

/* simple hash is enough for variation of macaddr */
#define ACL_HASH(addr)  \
        (((const u_int8_t *)(addr))[IEEE80211_ADDR_LEN - 1] % ACL_HASHSIZE)

MALLOC_DEFINE(M_80211_ACL, "acl", "802.11 station acl");

static  int acl_free_all(struct ieee80211com *);

static int
acl_attach(struct ieee80211com *ic)
{
        struct aclstate *as;

        as = malloc(sizeof(struct aclstate),
                M_80211_ACL, M_WAITOK | M_ZERO);
        ACL_LOCK_INIT(as, "acl");
        TAILQ_INIT(&as->as_list);
        as->as_policy = ACL_POLICY_OPEN;
        as->as_ic = ic;
        ic->ic_as = as;
        return 1;
}

static void
acl_detach(struct ieee80211com *ic)
{
        struct aclstate *as = ic->ic_as;

        acl_free_all(ic);
        ic->ic_as = NULL;
        ACL_LOCK_DESTROY(as);
        free(as, M_DEVBUF);
}

static __inline struct acl *
_find_acl(struct aclstate *as, const u_int8_t *macaddr)
{
        struct acl *acl;
        int hash;

        hash = ACL_HASH(macaddr);
        LIST_FOREACH(acl, &as->as_hash[hash], acl_hash) {
                if (IEEE80211_ADDR_EQ(acl->acl_macaddr, macaddr))
                        return acl;
        }
        return NULL;
}

static void
_acl_free(struct aclstate *as, struct acl *acl)
{
        ACL_LOCK_ASSERT(as);

        TAILQ_REMOVE(&as->as_list, acl, acl_list);
        LIST_REMOVE(acl, acl_hash);
        free(acl, M_80211_ACL);
        as->as_nacls--;
}

static int
acl_check(struct ieee80211com *ic, const u_int8_t mac[IEEE80211_ADDR_LEN])
{
        struct aclstate *as = ic->ic_as;

        switch (as->as_policy) {
        case ACL_POLICY_OPEN:
                return 1;
        case ACL_POLICY_ALLOW:
                return _find_acl(as, mac) != NULL;
        case ACL_POLICY_DENY:
                return _find_acl(as, mac) == NULL;
        }
        return 0;               /* should not happen */
}

static int
acl_add(struct ieee80211com *ic, const u_int8_t mac[IEEE80211_ADDR_LEN])
{
        struct aclstate *as = ic->ic_as;
        struct acl *acl, *new;
        int hash;

        new = malloc(sizeof(struct acl), M_80211_ACL, M_WAITOK | M_ZERO);

        ACL_LOCK(as);
        hash = ACL_HASH(mac);
        LIST_FOREACH(acl, &as->as_hash[hash], acl_hash) {
                if (IEEE80211_ADDR_EQ(acl->acl_macaddr, mac)) {
                        ACL_UNLOCK(as);
                        free(new, M_80211_ACL);
                        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ACL,
                                "ACL: add %s failed, already present\n",
                                ether_sprintf(mac));
                        return EEXIST;
                }
        }
        IEEE80211_ADDR_COPY(new->acl_macaddr, mac);
        TAILQ_INSERT_TAIL(&as->as_list, new, acl_list);
        LIST_INSERT_HEAD(&as->as_hash[hash], new, acl_hash);
        as->as_nacls++;
        ACL_UNLOCK(as);

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ACL,
                "ACL: add %s\n", ether_sprintf(mac));
        return 0;
}

static int
acl_remove(struct ieee80211com *ic, const u_int8_t mac[IEEE80211_ADDR_LEN])
{
        struct aclstate *as = ic->ic_as;
        struct acl *acl;

        ACL_LOCK(as);
        acl = _find_acl(as, mac);
        if (acl != NULL)
                _acl_free(as, acl);
        ACL_UNLOCK(as);

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ACL,
                "ACL: remove %s%s\n", ether_sprintf(mac),
                acl == NULL ? ", not present" : "");

        return (acl == NULL ? ENOENT : 0);
}

static int
acl_free_all(struct ieee80211com *ic)
{
        struct aclstate *as = ic->ic_as;
        struct acl *acl;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ACL, "ACL: %s\n", "free all");

        ACL_LOCK(as);
        while ((acl = TAILQ_FIRST(&as->as_list)) != NULL)
                _acl_free(as, acl);
        ACL_UNLOCK(as);

        return 0;
}

static int
acl_setpolicy(struct ieee80211com *ic, int policy)
{
        struct aclstate *as = ic->ic_as;

        IEEE80211_DPRINTF(ic, IEEE80211_MSG_ACL,
                "ACL: set policy to %u\n", policy);

        switch (policy) {
        case IEEE80211_MACCMD_POLICY_OPEN:
                as->as_policy = ACL_POLICY_OPEN;
                break;
        case IEEE80211_MACCMD_POLICY_ALLOW:
                as->as_policy = ACL_POLICY_ALLOW;
                break;
        case IEEE80211_MACCMD_POLICY_DENY:
                as->as_policy = ACL_POLICY_DENY;
                break;
        default:
                return EINVAL;
        }
        return 0;
}

static int
acl_getpolicy(struct ieee80211com *ic)
{
        struct aclstate *as = ic->ic_as;

        return as->as_policy;
}

static int
acl_setioctl(struct ieee80211com *ic,
    struct ieee80211req *ireq)
{

        return EINVAL;
}

static int
acl_getioctl(struct ieee80211com *ic, struct ieee80211req *ireq)
{
        struct aclstate *as = ic->ic_as;
        struct acl *acl;
        struct ieee80211req_maclist *ap;
        int error;
        uint32_t i, space;

        switch (ireq->i_val) {
        case IEEE80211_MACCMD_POLICY:
                ireq->i_val = as->as_policy;
                return 0;
        case IEEE80211_MACCMD_LIST:
                space = as->as_nacls * IEEE80211_ADDR_LEN;
                if (ireq->i_len == 0) {
                        ireq->i_len = space;    /* return required space */
                        return 0;               /* NB: must not error */
                }
                ap = malloc(space, M_TEMP, M_WAITOK);
                i = 0;
                ACL_LOCK(as);
                TAILQ_FOREACH(acl, &as->as_list, acl_list) {
                        IEEE80211_ADDR_COPY(ap[i].ml_macaddr, acl->acl_macaddr);
                        i++;
                }
                ACL_UNLOCK(as);
                if (ireq->i_len >= space) {
                        error = copyout(ap, ireq->i_data, space);
                        ireq->i_len = space;
                } else
                        error = copyout(ap, ireq->i_data, ireq->i_len);
                free(ap, M_TEMP);
                return error;
        }
        return EINVAL;
}

static const struct ieee80211_aclator mac = {
        .iac_name       = "mac",
        .iac_attach     = acl_attach,
        .iac_detach     = acl_detach,
        .iac_check      = acl_check,
        .iac_add        = acl_add,
        .iac_remove     = acl_remove,
        .iac_flush      = acl_free_all,
        .iac_setpolicy  = acl_setpolicy,
        .iac_getpolicy  = acl_getpolicy,
        .iac_setioctl   = acl_setioctl,
        .iac_getioctl   = acl_getioctl,
};