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/*
* TAP-Win32/TAP-Win64 -- A kernel driver to provide virtual tap
* device functionality on Windows.
*
* This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
*
* This source code is Copyright (C) 2002-2008 Telethra, Inc.,
* and is released under the GPL version 2 (see below), however due
* to the extra costs of supporting Windows Vista, OpenVPN Solutions
* LLC reserves the right to change the terms of the TAP-Win32/TAP-Win64
* license for versions 9.1 and higher prior to the official release of
* OpenVPN 2.1.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define INSTANCE_KEY(a) ((PVOID)((a)->m_Extension.m_TapDevice))
#define N_INSTANCE_BUCKETS 256
typedef struct _INSTANCE {
struct _INSTANCE *next;
TapAdapterPointer m_Adapter;
} INSTANCE;
typedef struct {
INSTANCE *list;
MUTEX lock;
} INSTANCE_BUCKET;
typedef struct {
INSTANCE_BUCKET buckets[N_INSTANCE_BUCKETS];
} INSTANCE_HASH;
INSTANCE_HASH *g_InstanceHash = NULL;
// must return a hash >= 0 and < N_INSTANCE_BUCKETS
int
InstanceHashValue (PVOID addr)
{
UCHAR *p = (UCHAR *) &addr;
if (sizeof (addr) == 4)
return p[0] ^ p[1] ^ p[2] ^ p[3];
else if (sizeof (addr) == 8)
return p[0] ^ p[1] ^ p[2] ^ p[3] ^ p[4] ^ p[5] ^ p[6] ^ p[7];
else
{
MYASSERT (0);
}
}
BOOLEAN
InitInstanceList (VOID)
{
MYASSERT (g_InstanceHash == NULL);
g_InstanceHash = MemAlloc (sizeof (INSTANCE_HASH), TRUE);
if (g_InstanceHash)
{
int i;
for (i = 0; i < N_INSTANCE_BUCKETS; ++i)
INIT_MUTEX (&g_InstanceHash->buckets[i].lock);
return TRUE;
}
else
return FALSE;
}
int
NInstances (VOID)
{
int i, n = 0;
if (g_InstanceHash)
{
for (i = 0; i < N_INSTANCE_BUCKETS; ++i)
{
BOOLEAN got_lock;
INSTANCE_BUCKET *ib = &g_InstanceHash->buckets[i];
ACQUIRE_MUTEX_ADAPTIVE (&ib->lock, got_lock);
if (got_lock)
{
INSTANCE *current;
for (current = ib->list; current != NULL; current = current->next)
++n;
RELEASE_MUTEX (&ib->lock);
}
else
return -1;
}
}
return n;
}
int
InstanceMaxBucketSize (VOID)
{
int i, n = 0;
if (g_InstanceHash)
{
for (i = 0; i < N_INSTANCE_BUCKETS; ++i)
{
BOOLEAN got_lock;
int bucket_size = 0;
INSTANCE_BUCKET *ib = &g_InstanceHash->buckets[i];
ACQUIRE_MUTEX_ADAPTIVE (&ib->lock, got_lock);
if (got_lock)
{
INSTANCE *current;
for (current = ib->list; current != NULL; current = current->next)
++bucket_size;
if (bucket_size > n)
n = bucket_size;
RELEASE_MUTEX (&ib->lock);
}
else
return -1;
}
}
return n;
}
VOID
FreeInstanceList (VOID)
{
if (g_InstanceHash)
{
MYASSERT (NInstances() == 0);
MemFree (g_InstanceHash, sizeof (INSTANCE_HASH));
g_InstanceHash = NULL;
}
}
BOOLEAN
AddAdapterToInstanceList (TapAdapterPointer p_Adapter)
{
BOOLEAN got_lock;
BOOLEAN ret = FALSE;
const int hash = InstanceHashValue(INSTANCE_KEY(p_Adapter));
INSTANCE_BUCKET *ib = &g_InstanceHash->buckets[hash];
DEBUGP (("[TAP] AddAdapterToInstanceList hash=%d\n", hash));
ACQUIRE_MUTEX_ADAPTIVE (&ib->lock, got_lock);
if (got_lock)
{
INSTANCE *i = MemAlloc (sizeof (INSTANCE), FALSE);
if (i)
{
MYASSERT (p_Adapter);
i->m_Adapter = p_Adapter;
i->next = ib->list;
ib->list = i;
ret = TRUE;
}
RELEASE_MUTEX (&ib->lock);
}
return ret;
}
BOOLEAN
RemoveAdapterFromInstanceList (TapAdapterPointer p_Adapter)
{
BOOLEAN got_lock;
BOOLEAN ret = FALSE;
INSTANCE_BUCKET *ib = &g_InstanceHash->buckets[InstanceHashValue(INSTANCE_KEY(p_Adapter))];
ACQUIRE_MUTEX_ADAPTIVE (&ib->lock, got_lock);
if (got_lock)
{
INSTANCE *current, *prev=NULL;
for (current = ib->list; current != NULL; current = current->next)
{
if (current->m_Adapter == p_Adapter) // found match
{
if (prev)
prev->next = current->next;
else
ib->list = current->next;
MemFree (current->m_Adapter, sizeof (TapAdapter));
MemFree (current, sizeof (INSTANCE));
ret = TRUE;
break;
}
prev = current;
}
RELEASE_MUTEX (&ib->lock);
}
return ret;
}
TapAdapterPointer
LookupAdapterInInstanceList (PDEVICE_OBJECT p_DeviceObject)
{
BOOLEAN got_lock;
TapAdapterPointer ret = NULL;
INSTANCE_BUCKET *ib = &g_InstanceHash->buckets[InstanceHashValue((PVOID)p_DeviceObject)];
ACQUIRE_MUTEX_ADAPTIVE (&ib->lock, got_lock);
if (got_lock)
{
INSTANCE *current, *prev=NULL;
for (current = ib->list; current != NULL; current = current->next)
{
if (p_DeviceObject == INSTANCE_KEY (current->m_Adapter)) // found match
{
// move it to head of list
if (prev)
{
prev->next = current->next;
current->next = ib->list;
ib->list = current;
}
ret = ib->list->m_Adapter;
break;
}
prev = current;
}
RELEASE_MUTEX (&ib->lock);
}
return ret;
}
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