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/* net/atm/atm_misc.c - Various functions for use by ATM drivers */

/* Written 1995-2000 by Werner Almesberger, EPFL ICA */

#include <linux/module.h>

#include <linux/atm.h>

#include <linux/atmdev.h>

#include <linux/skbuff.h>

#include <linux/sonet.h>

#include <linux/bitops.h>

#include <asm/atomic.h>

#include <asm/errno.h>

int atm_charge(struct atm_vcc *vcc,int truesize)

{

        atm_force_charge(vcc,truesize);

        if (atomic_read(&vcc->sk->rmem_alloc) <= vcc->sk->rcvbuf) return 1;

        atm_return(vcc,truesize);

        atomic_inc(&vcc->stats->rx_drop);

        return 0;

}

struct sk_buff *atm_alloc_charge(struct atm_vcc *vcc,int pdu_size,

    int gfp_flags)

{

        int guess = atm_guess_pdu2truesize(pdu_size);

        atm_force_charge(vcc,guess);

        if (atomic_read(&vcc->sk->rmem_alloc) <= vcc->sk->rcvbuf) {

                struct sk_buff *skb = alloc_skb(pdu_size,gfp_flags);

                if (skb) {

                        atomic_add(skb->truesize-guess,&vcc->sk->rmem_alloc);

                        return skb;

                }

        }

        atm_return(vcc,guess);

        atomic_inc(&vcc->stats->rx_drop);

        return NULL;

}

static int check_ci(struct atm_vcc *vcc,short vpi,int vci)

{

        struct sock *s;

        struct atm_vcc *walk;

        for (s = vcc_sklist; s; s = s->next) {

                walk = s->protinfo.af_atm;

                if (walk->dev != vcc->dev)

                        continue;

                if (test_bit(ATM_VF_ADDR,&walk->flags) && walk->vpi == vpi &&

                    walk->vci == vci && ((walk->qos.txtp.traffic_class !=

                    ATM_NONE && vcc->qos.txtp.traffic_class != ATM_NONE) ||

                    (walk->qos.rxtp.traffic_class != ATM_NONE &&

                    vcc->qos.rxtp.traffic_class != ATM_NONE)))

                        return -EADDRINUSE;

        }

                /* allow VCCs with same VPI/VCI iff they don't collide on

                   TX/RX (but we may refuse such sharing for other reasons,

                   e.g. if protocol requires to have both channels) */

        return 0;

}

int atm_find_ci(struct atm_vcc *vcc,short *vpi,int *vci)

{

        static short p = 0; /* poor man's per-device cache */

        static int c = 0;

        short old_p;

        int old_c;

        int err;

        read_lock(&vcc_sklist_lock);

        if (*vpi != ATM_VPI_ANY && *vci != ATM_VCI_ANY) {

                err = check_ci(vcc,*vpi,*vci);

                read_unlock(&vcc_sklist_lock);

                return err;

        }

        /* last scan may have left values out of bounds for current device */

        if (*vpi != ATM_VPI_ANY) p = *vpi;

        else if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;

        if (*vci != ATM_VCI_ANY) c = *vci;

        else if (c < ATM_NOT_RSV_VCI || c >= 1 << vcc->dev->ci_range.vci_bits)

                        c = ATM_NOT_RSV_VCI;

        old_p = p;

        old_c = c;

        do {

                if (!check_ci(vcc,p,c)) {

                        *vpi = p;

                        *vci = c;

                        read_unlock(&vcc_sklist_lock);

                        return 0;

                }

                if (*vci == ATM_VCI_ANY) {

                        c++;

                        if (c >= 1 << vcc->dev->ci_range.vci_bits)

                                c = ATM_NOT_RSV_VCI;

                }

                if ((c == ATM_NOT_RSV_VCI || *vci != ATM_VCI_ANY) &&

                    *vpi == ATM_VPI_ANY) {

                        p++;

                        if (p >= 1 << vcc->dev->ci_range.vpi_bits) p = 0;

                }

        }

        while (old_p != p || old_c != c);

        read_unlock(&vcc_sklist_lock);

        return -EADDRINUSE;

}

/*

 * atm_pcr_goal returns the positive PCR if it should be rounded up, the

 * negative PCR if it should be rounded down, and zero if the maximum available

 * bandwidth should be used.

 *

 * The rules are as follows (* = maximum, - = absent (0), x = value "x",

 * (x+ = x or next value above x, x- = x or next value below):

 *

 *      min max pcr     result          min max pcr     result

 *      -   -   -       * (UBR only)    x   -   -       x+

 *      -   -   *       *               x   -   *       *

 *      -   -   z       z-              x   -   z       z-

 *      -   *   -       *               x   *   -       x+

 *      -   *   *       *               x   *   *       *

 *      -   *   z       z-              x   *   z       z-

 *      -   y   -       y-              x   y   -       x+

 *      -   y   *       y-              x   y   *       y-

 *      -   y   z       z-              x   y   z       z-

 *

 * All non-error cases can be converted with the following simple set of rules:

 *

 *   if pcr == z then z-

 *   else if min == x && pcr == - then x+

 *     else if max == y then y-

 *       else *

 */

int atm_pcr_goal(struct atm_trafprm *tp)

{

        if (tp->pcr && tp->pcr != ATM_MAX_PCR) return -tp->pcr;

        if (tp->min_pcr && !tp->pcr) return tp->min_pcr;

        if (tp->max_pcr != ATM_MAX_PCR) return -tp->max_pcr;

        return 0;

}

void sonet_copy_stats(struct k_sonet_stats *from,struct sonet_stats *to)

{

#define __HANDLE_ITEM(i) to->i = atomic_read(&from->i)

        __SONET_ITEMS

#undef __HANDLE_ITEM

}

void sonet_subtract_stats(struct k_sonet_stats *from,struct sonet_stats *to)

{

#define __HANDLE_ITEM(i) atomic_sub(to->i,&from->i)

        __SONET_ITEMS

#undef __HANDLE_ITEM

}

EXPORT_SYMBOL(atm_charge);

EXPORT_SYMBOL(atm_alloc_charge);

EXPORT_SYMBOL(atm_find_ci);

EXPORT_SYMBOL(atm_pcr_goal);

EXPORT_SYMBOL(sonet_copy_stats);

EXPORT_SYMBOL(sonet_subtract_stats);