dco-win: factor out getting dco version info own function

Instead of having duplicated code to get dco version for data_v3 checks and for version info, have it in one place and store the version in dco context - the latter is a preparation for dco v2 support (multi-peer). Change-Id: I8e8ddd35bd3cc3334faf7f57118d1892512ae9f7 Signed-off-by: Lev Stipakov <[email protected]>
lstipakov · Sep 5, 2024 · 76d42f1 · 76d42f1
1 parent a9d38cd
commit 76d42f1
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Showing 2 changed files with 52 additions and 56 deletions.
diff --git a/src/openvpn/dco_win.c b/src/openvpn/dco_win.c
@@ -52,11 +52,55 @@ create_dco_handle(const char *devname, struct gc_arena *gc)
     return tt;
 }
 
+static void
+dco_get_version(OVPN_VERSION *version)
+{
+    bool res = false;
+
+    HANDLE h = CreateFile("\\\\.\\ovpn-dco-ver", GENERIC_READ,
+        0, NULL, OPEN_EXISTING, 0, NULL);
+
+    if (h == INVALID_HANDLE_VALUE)
+    {
+        /* fallback to a "normal" device, this will fail if device is already in use */
+        h = CreateFile("\\\\.\\ovpn-dco", GENERIC_READ,
+            0, NULL, OPEN_EXISTING, 0, NULL);
+    }
+
+    if (h == INVALID_HANDLE_VALUE)
+    {
+        goto done;
+    }
+
+    DWORD bytes_returned = 0;
+    if (!DeviceIoControl(h, OVPN_IOCTL_GET_VERSION, NULL, 0,
+        version, sizeof(*version), &bytes_returned, NULL))
+    {
+        goto done;
+    }
+
+done:
+    if (h != INVALID_HANDLE_VALUE)
+    {
+        CloseHandle(h);
+    }
+
+    msg(D_DCO_DEBUG, "dco version: %d.%d.%d", version->Major, version->Minor, version->Patch);
+}
+
+static inline
+bool dco_version_supports_data_v3(OVPN_VERSION *version)
+{
+    return (version->Major > 1) || (version->Minor >= 4);
+}
+
 bool
 ovpn_dco_init(int mode, dco_context_t *dco)
 {
-    dco->supports_data_v3 = dco_supports_data_v3(NULL);
-    msg(D_DCO_DEBUG, "dco supports data_v3: %d", dco->supports_data_v3);
+    dco_get_version(&dco->version);
+    dco->supports_data_v3 = dco_version_supports_data_v3(&dco->version);
+
+    msg(D_DCO_DEBUG, "dco data_v3: %d", dco->supports_data_v3);
 
     return true;
 }
@@ -428,33 +472,9 @@ const char *
 dco_version_string(struct gc_arena *gc)
 {
     OVPN_VERSION version;
-    ZeroMemory(&version, sizeof(OVPN_VERSION));
+    ZeroMemory(&version, sizeof(version));
 
-    /* first, try a non-exclusive control device, available from 1.3.0 */
-    HANDLE h = CreateFile("\\\\.\\ovpn-dco-ver", GENERIC_READ,
-                          0, NULL, OPEN_EXISTING, 0, NULL);
-
-    if (h == INVALID_HANDLE_VALUE)
-    {
-        /* fallback to a "normal" device, this will fail if device is already in use */
-        h = CreateFile("\\\\.\\ovpn-dco", GENERIC_READ,
-                       0, NULL, OPEN_EXISTING, 0, NULL);
-    }
-
-    if (h == INVALID_HANDLE_VALUE)
-    {
-        return "N/A";
-    }
-
-    DWORD bytes_returned = 0;
-    if (!DeviceIoControl(h, OVPN_IOCTL_GET_VERSION, NULL, 0,
-                         &version, sizeof(version), &bytes_returned, NULL))
-    {
-        CloseHandle(h);
-        return "N/A";
-    }
-
-    CloseHandle(h);
+    dco_get_version(&version);
 
     struct buffer out = alloc_buf_gc(256, gc);
     buf_printf(&out, "%ld.%ld.%ld", version.Major, version.Minor, version.Patch);
@@ -538,36 +558,11 @@ dco_get_supported_ciphers()
 bool
 dco_supports_data_v3(struct context *c)
 {
-    bool res = false;
-
-    HANDLE h = CreateFile("\\\\.\\ovpn-dco-ver", GENERIC_READ,
-                          0, NULL, OPEN_EXISTING, 0, NULL);
-
-    if (h == INVALID_HANDLE_VALUE)
-    {
-        goto done;
-    }
-
     OVPN_VERSION version;
-    ZeroMemory(&version, sizeof(OVPN_VERSION));
-
-    DWORD bytes_returned = 0;
-    if (!DeviceIoControl(h, OVPN_IOCTL_GET_VERSION, NULL, 0,
-                         &version, sizeof(version), &bytes_returned, NULL))
-    {
-        goto done;
-    }
-
-    /* data_v3 is supported starting from 1.4 */
-    res = (version.Major > 1) || (version.Minor >= 4);
-
-done:
-    if (h != INVALID_HANDLE_VALUE)
-    {
-        CloseHandle(h);
-    }
+    ZeroMemory(&version, sizeof(version));
+    dco_get_version(&version);
 
-    return res;
+    return dco_version_supports_data_v3(&version);
 }
 
 #endif /* defined(_WIN32) */
diff --git a/src/openvpn/dco_win.h b/src/openvpn/dco_win.h
@@ -34,6 +34,7 @@ typedef OVPN_CIPHER_ALG dco_cipher_t;
 struct dco_context {
     struct tuntap *tt;
     bool supports_data_v3;
+    OVPN_VERSION version;
 };
 
 typedef struct dco_context dco_context_t;