/*      $NetBSD: if_media.c,v 1.54 2022/09/03 02:47:59 thorpej Exp $    */

/*-
 * Copyright (c) 1998, 2020 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION 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.
 */

/*
 * Copyright (c) 1997
 *      Jonathan Stone and Jason R. Thorpe.  All rights reserved.
 *
 * This software is derived from information provided by Matt Thomas.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Jonathan Stone
 *      and Jason R. Thorpe for the NetBSD Project.
 * 4. The names of the authors may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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.
 */

/*
 * BSD/OS-compatible network interface media selection.
 *
 * Where it is safe to do so, this code strays slightly from the BSD/OS
 * design.  Software which uses the API (device drivers, basically)
 * shouldn't notice any difference.
 *
 * Many thanks to Matt Thomas for providing the information necessary
 * to implement this interface.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_media.c,v 1.54 2022/09/03 02:47:59 thorpej Exp $");

#define __IFMEDIA_PRIVATE

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/kmem.h>

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

static void     ifmedia_status(struct ifmedia *, struct ifnet *,
                    struct ifmediareq *);
static struct ifmedia_entry *
                ifmedia_match_locked(struct ifmedia *, u_int, u_int);

/*
 * Compile-time options:
 * IFMEDIA_DEBUG:
 *      Turn on implementation-level debug printfs.
 *      Useful for debugging newly-ported drivers.
 */

#ifdef IFMEDIA_DEBUG
int     ifmedia_debug = 0;
static  void ifmedia_printword(int);
#endif

/*
 * We need to implement a recursive mutex to handle the un-converted
 * driver case.  For a fully MP-safe driver, the media lock will be
 * held before calling any of the entry points that require it.  However,
 * this is not necessarily the case for a driver that hasn't yet been
 * converted, and the entry point calls may be nested (for example
 * mii_ifmedia_change -> ether_mediachange -> mii_mediachg).  Luckily,
 * the nesting won't be very deep, and 4 nested holds should be plenty.
 */
#define IFM_L_OWNLOCK           0x01
#define IFM_L_COUNT_MASK        0x3UL
#define IFM_L_CPU_MASK          ~(IFM_L_COUNT_MASK)

void
ifmedia_lock_for_legacy(struct ifmedia *ifm)
{
        uintptr_t cnt = IFM_L_OWNLOCK;
        uintptr_t ci;

        if (mutex_tryenter(ifm->ifm_lock)) {
                goto gotit;
        }

        kpreempt_disable();
        ci = (uintptr_t)curcpu();
        if ((ifm->ifm_legacy & IFM_L_CPU_MASK) == ci) {
                cnt = ifm->ifm_legacy & IFM_L_COUNT_MASK;
                KASSERT(cnt < IFM_L_COUNT_MASK);
                cnt++;
                kpreempt_enable();
                goto gotit;
        }
        kpreempt_enable();

        mutex_enter(ifm->ifm_lock);
 gotit:
        KASSERT(kpreempt_disabled());
        ci = (uintptr_t)curcpu();
        KASSERT((ci & IFM_L_CPU_MASK) == ci);
        ifm->ifm_legacy = ci | cnt;
}

void
ifmedia_unlock_for_legacy(struct ifmedia *ifm)
{
        uintptr_t cnt;
        uintptr_t ci = (uintptr_t)curcpu();

        KASSERT(kpreempt_disabled());
        KASSERT((ifm->ifm_legacy & IFM_L_CPU_MASK) == ci);
        cnt = ifm->ifm_legacy & IFM_L_COUNT_MASK;
        KASSERT(cnt != 0);
        if (cnt == IFM_L_OWNLOCK) {
                ifm->ifm_legacy = IFM_L_OWNLOCK;
                mutex_exit(ifm->ifm_lock);
                return;
        }
        cnt--;
        ifm->ifm_legacy = ci | cnt;
}

/*
 * Initialize if_media struct for a specific interface instance.
 */
void
ifmedia_init_with_lock(struct ifmedia *ifm, int dontcare_mask,
    ifm_change_cb_t change_callback, ifm_stat_cb_t status_callback,
    kmutex_t *lock)
{

        /*
         * XXX Would really like to assert:
         *
         *      !if_is_mpsafe(ifp) || ((if_is_mpsafe(ifp) && lock != NULL)
         *
         * ...but we don't have access to the ifnet here.
         */

        TAILQ_INIT(&ifm->ifm_list);
        ifm->ifm_cur = NULL;
        ifm->ifm_media = IFM_NONE;
        ifm->ifm_mask = dontcare_mask;          /* IF don't-care bits */
        ifm->ifm_change = change_callback;
        ifm->ifm_status = status_callback;
        ifm->ifm_legacy = 0;

        if (lock == NULL) {
                /*
                 * This is to support drivers that are not yet MP-safe
                 * with regard to the ifmedia layer.  In these cases,
                 * we supply the lock and we ensure it's taken upon entry
                 * to various routines that expect it to be held.  When
                 * we do this, we expect that the driver is in general a
                 * non-MP-safe driver and has already gone to splnet().
                 */
                lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET);
                ifm->ifm_legacy = IFM_L_OWNLOCK;
        }
        ifm->ifm_lock = lock;
}

void
ifmedia_init(struct ifmedia *ifm, int dontcare_mask,
    ifm_change_cb_t change_callback, ifm_stat_cb_t status_callback)
{
        ifmedia_init_with_lock(ifm, dontcare_mask, change_callback,
            status_callback, NULL);
}

/*
 * Free resources associated with an ifmedia.
 */
void
ifmedia_fini(struct ifmedia *ifm)
{

        ifmedia_removeall(ifm);

        if (ifm->ifm_legacy) {
                KASSERT(ifm->ifm_legacy == IFM_L_OWNLOCK);
                mutex_obj_free(ifm->ifm_lock);
        }
        ifm->ifm_legacy = 0;
        ifm->ifm_lock = NULL;
}

int
ifmedia_change(struct ifmedia *ifm, struct ifnet *ifp)
{
        int rv;

        IFMEDIA_LOCK_FOR_LEGACY(ifm);
        KASSERT(ifmedia_locked(ifm));
        if (ifm->ifm_change)
                rv = (*ifm->ifm_change)(ifp);
        else
                rv = -1;
        IFMEDIA_UNLOCK_FOR_LEGACY(ifm);

        return rv;
}

static void
ifmedia_status(struct ifmedia *ifm, struct ifnet *ifp, struct ifmediareq *ifmr)
{

        KASSERT(ifmedia_locked(ifm));
        if (ifm->ifm_status == NULL)
                return;
        (*ifm->ifm_status)(ifp, ifmr);
}

/*
 * Add a media configuration to the list of supported media
 * for a specific interface instance.
 */
static void
ifmedia_add_entry(struct ifmedia *ifm, int mword, int data, void *aux,
    struct ifmedia_entry *entry)
{

#ifdef IFMEDIA_DEBUG
        if (ifmedia_debug) {
                if (ifm == NULL) {
                        printf("ifmedia_add: null ifm\n");
                        return;
                }
                printf("Adding entry for ");
                ifmedia_printword(mword);
        }
#endif

        entry->ifm_media = mword;
        entry->ifm_data = data;
        entry->ifm_aux = aux;
        TAILQ_INSERT_TAIL(&ifm->ifm_list, entry, ifm_list);
}

void
ifmedia_add(struct ifmedia *ifm, int mword, int data, void *aux)
{
        struct ifmedia_entry *entry;

        entry = kmem_zalloc(sizeof(*entry), KM_SLEEP);
        ifmedia_lock(ifm);
        ifmedia_add_entry(ifm, mword, data, aux, entry);
        ifmedia_unlock(ifm);
}

/*
 * Add an array of media configurations to the list of
 * supported media for a specific interface instance.
 */
void
ifmedia_list_add(struct ifmedia *ifm, struct ifmedia_entry *lp, int count)
{
        int i;

        for (i = 0; i < count; i++)
                ifmedia_add(ifm, lp[i].ifm_media, lp[i].ifm_data,
                    lp[i].ifm_aux);
}

/*
 * Set the default active media.
 *
 * Called by device-specific code which is assumed to have already
 * selected the default media in hardware.  We do _not_ call the
 * media-change callback.
 */
void
ifmedia_set(struct ifmedia *ifm, int target)
{
        struct ifmedia_entry *match, *entry = NULL;

        ifmedia_lock(ifm);
        match = ifmedia_match_locked(ifm, target, ifm->ifm_mask);

        /*
         * If we didn't find the requested media, then we try to fall
         * back to target-type (IFM_ETHER, e.g.) | IFM_NONE.  If that's
         * not on the list, then we add it and set the media to it.
         *
         * Since ifmedia_set is almost always called with IFM_AUTO or
         * with a known-good media, this really should only occur if we:
         *
         * a) didn't find any PHYs, or
         * b) didn't find an autoselect option on the PHY when the
         *    parent ethernet driver expected to.
         *
         * In either case, it makes sense to select no media.
         */
        if (match == NULL) {
                printf("ifmedia_set: no match for 0x%x/0x%x\n",
                    target, ~ifm->ifm_mask);
                target = (target & IFM_NMASK) | IFM_NONE;
                match = ifmedia_match_locked(ifm, target, ifm->ifm_mask);
                if (match == NULL) {
                        ifmedia_unlock(ifm);
                        entry = kmem_zalloc(sizeof(*entry), KM_SLEEP);
                        ifmedia_lock(ifm);
                        match = ifmedia_match_locked(ifm, target,
                            ifm->ifm_mask);
                        if (match == NULL) {
                                ifmedia_add_entry(ifm, target, 0, NULL, entry);
                                entry = NULL;
                        }
                        match = ifmedia_match_locked(ifm, target,
                            ifm->ifm_mask);
                        if (match == NULL)
                                panic("ifmedia_set failed");
                }
        }
        ifm->ifm_cur = match;
        ifmedia_unlock(ifm);

        if (entry)
                kmem_free(entry, sizeof(*entry));

#ifdef IFMEDIA_DEBUG
        if (ifmedia_debug) {
                printf("ifmedia_set: target ");
                ifmedia_printword(target);
                printf("ifmedia_set: setting to ");
                ifmedia_printword(ifm->ifm_cur->ifm_media);
        }
#endif
}

static int
ifmedia_getwords(struct ifmedia * const ifm, int *words, int maxwords)
{
        struct ifmedia_entry *ep;
        int nwords = 0;

        KASSERT(ifmedia_locked(ifm));

        TAILQ_FOREACH(ep, &ifm->ifm_list, ifm_list) {
                if (words != NULL && nwords < maxwords) {
                        words[nwords] = ep->ifm_media;
                }
                nwords++;
        }

        return nwords;
}

#define IFMEDIA_IOCTL_LOCK(ifm)                                         \
do {                                                                    \
        if (ifmedia_islegacy(ifm))                                      \
                ifmedia_lock_for_legacy(ifm);                           \
        else                                                            \
                ifmedia_lock(ifm);                                      \
} while (/*CONSTCOND*/0)

#define IFMEDIA_IOCTL_UNLOCK(ifm)                                       \
do {                                                                    \
        if (ifmedia_islegacy(ifm))                                      \
                ifmedia_unlock_for_legacy(ifm);                         \
        else                                                            \
                ifmedia_unlock(ifm);                                    \
} while (/*CONSTCOND*/0)

/*
 * Device-independent media ioctl support function.
 */
int
ifmedia_ioctl(struct ifnet *ifp, struct ifreq *ifr, struct ifmedia *ifm,
    u_long cmd)
{
        struct ifmedia_entry *match;
        struct ifmediareq *ifmr = (struct ifmediareq *)ifr;
        int error = 0;

        if (ifp == NULL || ifr == NULL || ifm == NULL)
                return EINVAL;

        KERNEL_LOCK_UNLESS_IFP_MPSAFE(ifp);

        switch (cmd) {
        case SIOCSIFMEDIA:      /* Set the current media. */
        {
                struct ifmedia_entry *oldentry;
                u_int oldmedia;
                u_int newmedia = ifr->ifr_media;

                IFMEDIA_IOCTL_LOCK(ifm);

                match = ifmedia_match_locked(ifm, newmedia, ifm->ifm_mask);
                if (match == NULL) {
#ifdef IFMEDIA_DEBUG
                        if (ifmedia_debug) {
                                printf("ifmedia_ioctl: no media found for "
                                    "0x%08x\n", newmedia);
                        }
#endif
                        IFMEDIA_IOCTL_UNLOCK(ifm);
                        error = EINVAL;
                        break;
                }

                /*
                 * If no change, we're done.
                 * XXX Automedia may involve software intervention.
                 *     Keep going in case the connected media changed.
                 *     Similarly, if best match changed (kernel debugger?).
                 */
                if ((IFM_SUBTYPE(newmedia) != IFM_AUTO) &&
                    (newmedia == ifm->ifm_media) && (match == ifm->ifm_cur)) {
                        IFMEDIA_IOCTL_UNLOCK(ifm);
                        break;
                }

                /*
                 * We found a match, now make the driver switch to it.
                 * Make sure to preserve our old media type in case the
                 * driver can't switch.
                 */
#ifdef IFMEDIA_DEBUG
                if (ifmedia_debug) {
                        printf("ifmedia_ioctl: switching %s to ",
                            ifp->if_xname);
                        ifmedia_printword(match->ifm_media);
                }
#endif
                oldentry = ifm->ifm_cur;
                oldmedia = ifm->ifm_media;
                ifm->ifm_cur = match;
                ifm->ifm_media = newmedia;
                error = ifmedia_change(ifm, ifp);
                if (error) {
                        ifm->ifm_cur = oldentry;
                        ifm->ifm_media = oldmedia;
                }
                IFMEDIA_IOCTL_UNLOCK(ifm);
                break;
        }

        /* Get list of available media and current media on interface. */
        case SIOCGIFMEDIA:
        {
                int nwords1, nwords2;

                if (ifmr->ifm_count < 0) {
                        error = EINVAL;
                        break;
                }

                IFMEDIA_IOCTL_LOCK(ifm);
                ifmr->ifm_active = ifmr->ifm_current = ifm->ifm_cur ?
                    ifm->ifm_cur->ifm_media : IFM_NONE;
                ifmr->ifm_mask = ifm->ifm_mask;
                ifmr->ifm_status = 0;
                ifmedia_status(ifm, ifp, ifmr);

                /*
                 * Count them so we know how much is the max we'll
                 * need.
                 */
                nwords1 = nwords2 = ifmedia_getwords(ifm, NULL, 0);
                IFMEDIA_IOCTL_UNLOCK(ifm);

                if (ifmr->ifm_count != 0) {
                        int maxwords = MIN(nwords1, ifmr->ifm_count);
                        int *kptr = kmem_zalloc(maxwords * sizeof(int),
                            KM_SLEEP);

                        ifmedia_lock(ifm);
                        nwords2 = ifmedia_getwords(ifm, kptr, maxwords);
                        ifmedia_unlock(ifm);
                        error = copyout(kptr, ifmr->ifm_ulist,
                            maxwords * sizeof(int));
                        if (error == 0 && nwords2 > nwords1)
                                error = E2BIG;  /* oops! */
                        kmem_free(kptr, maxwords * sizeof(int));
                }
                /* Update with the real number */
                ifmr->ifm_count = nwords2;
                break;
        }

        default:
                error = EINVAL;
                break;
        }

        KERNEL_UNLOCK_UNLESS_IFP_MPSAFE(ifp);

        return error;
}

/*
 * Find media entry matching a given ifm word.
 */
static struct ifmedia_entry *
ifmedia_match_locked(struct ifmedia *ifm, u_int target, u_int mask)
{
        struct ifmedia_entry *match, *next;

        match = NULL;
        mask = ~mask;

        TAILQ_FOREACH(next, &ifm->ifm_list, ifm_list) {
                if ((next->ifm_media & mask) == (target & mask)) {
                        if (match) {
#if defined(IFMEDIA_DEBUG) || defined(DIAGNOSTIC)
                                printf("ifmedia_match: multiple match for "
                                    "0x%x/0x%x, selected instance %d\n",
                                    target, mask, IFM_INST(match->ifm_media));
#endif
                                break;
                        }
                        match = next;
                }
        }

        return match;
}

struct ifmedia_entry *
ifmedia_match(struct ifmedia *ifm, u_int target, u_int mask)
{
        struct ifmedia_entry *match;

        /*
         * N.B. We expect the caller is responsible fot the lifecycle
         * of the media entries.  Use with extreme caution.
         */

        ifmedia_lock(ifm);
        match = ifmedia_match_locked(ifm, target, mask);
        ifmedia_unlock(ifm);
        return match;
}

/*
 * Delete all media for a given instance.
 */
void
ifmedia_delete_instance(struct ifmedia *ifm, u_int inst)
{
        struct ifmedia_entry *ife, *nife;
        TAILQ_HEAD(, ifmedia_entry) dead_entries;

        TAILQ_INIT(&dead_entries);

        ifmedia_lock(ifm);
        TAILQ_FOREACH_SAFE(ife, &ifm->ifm_list, ifm_list, nife) {
                if (inst == IFM_INST_ANY ||
                    inst == IFM_INST(ife->ifm_media)) {
                        if (ifm->ifm_cur == ife) {
                                ifm->ifm_cur = NULL;
                                ifm->ifm_media = IFM_NONE;
                        }
                        TAILQ_REMOVE(&ifm->ifm_list, ife, ifm_list);
                        TAILQ_INSERT_TAIL(&dead_entries, ife, ifm_list);
                }
        }
        ifmedia_unlock(ifm);

        TAILQ_FOREACH_SAFE(ife, &dead_entries, ifm_list, nife) {
                TAILQ_REMOVE(&dead_entries, ife, ifm_list);
                kmem_free(ife, sizeof(*ife));
        }
}

void
ifmedia_removeall(struct ifmedia *ifm)
{

        ifmedia_delete_instance(ifm, IFM_INST_ANY);
}

/*
 * Compute the interface `baudrate' from the media, for the interface
 * metrics (used by routing daemons).
 */
static const struct ifmedia_baudrate ifmedia_baudrate_descriptions[] =
    IFM_BAUDRATE_DESCRIPTIONS;

uint64_t
ifmedia_baudrate(int mword)
{
        int i;

        for (i = 0; ifmedia_baudrate_descriptions[i].ifmb_word != 0; i++) {
                if (IFM_TYPE_SUBTYPE_MATCH(mword,
                    ifmedia_baudrate_descriptions[i].ifmb_word))
                        return ifmedia_baudrate_descriptions[i].ifmb_baudrate;
        }

        /* Not known. */
        return 0;
}

#ifdef IFMEDIA_DEBUG

static const struct ifmedia_description ifm_type_descriptions[] =
    IFM_TYPE_DESCRIPTIONS;

static const struct ifmedia_description ifm_subtype_descriptions[] =
    IFM_SUBTYPE_DESCRIPTIONS;

static const struct ifmedia_description ifm_option_descriptions[] =
    IFM_OPTION_DESCRIPTIONS;

/*
 * print a media word.
 */
static void
ifmedia_printword(int ifmw)
{
        const struct ifmedia_description *desc;
        int seen_option = 0;

        /* Print the top-level interface type. */
        for (desc = ifm_type_descriptions; desc->ifmt_string != NULL;
             desc++) {
                if (IFM_TYPE(ifmw) == desc->ifmt_word)
                        break;
        }
        if (desc->ifmt_string == NULL)
                printf("<unknown type> ");
        else
                printf("%s ", desc->ifmt_string);

        /* Print the subtype. */
        for (desc = ifm_subtype_descriptions; desc->ifmt_string != NULL;
             desc++) {
                if (IFM_TYPE_MATCH(desc->ifmt_word, ifmw) &&
                    IFM_SUBTYPE(desc->ifmt_word) == IFM_SUBTYPE(ifmw))
                        break;
        }
        if (desc->ifmt_string == NULL)
                printf("<unknown subtype>");
        else
                printf("%s", desc->ifmt_string);

        /* Print any options. */
        for (desc = ifm_option_descriptions; desc->ifmt_string != NULL;
             desc++) {
                if (IFM_TYPE_MATCH(desc->ifmt_word, ifmw) &&
                    (ifmw & desc->ifmt_word) != 0 &&
                    (seen_option & IFM_OPTIONS(desc->ifmt_word)) == 0) {
                        if (seen_option == 0)
                                printf(" <");
                        printf("%s%s", seen_option ? "," : "",
                            desc->ifmt_string);
                        seen_option |= IFM_OPTIONS(desc->ifmt_word);
                }
        }
        printf("%s\n", seen_option ? ">" : "");
}

#endif /* IFMEDIA_DEBUG */