/*      $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 */