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-rwxr-xr-xtap-win32/instance.c245
1 files changed, 245 insertions, 0 deletions
diff --git a/tap-win32/instance.c b/tap-win32/instance.c
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+++ b/tap-win32/instance.c
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+/*
+ * TAP-Win32 -- A kernel driver to provide virtual tap device
+ * functionality on Windows. Originally derived
+ * from the CIPE-Win32 project by Damion K. Wilson,
+ * with extensive modifications by James Yonan.
+ *
+ * All source code which derives from the CIPE-Win32 project is
+ * Copyright (C) Damion K. Wilson, 2003, and is released under the
+ * GPL version 2 (see below).
+ *
+ * All other source code is Copyright (C) 2002-2005 OpenVPN Solutions LLC,
+ * and is released under the GPL version 2 (see below).
+ *
+ * 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;
+}