diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 5e67a97..32f7e69 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -2,9 +2,12 @@
 <project version="4">
   <component name="ChangeListManager">
     <list default="true" id="208c8f22-eeea-487d-8a23-c2fce1eb1434" name="Default" comment="">
-      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/npd.iml" afterPath="$PROJECT_DIR$/.idea/npd.iml" />
       <change type="MODIFICATION" beforePath="$PROJECT_DIR$/.idea/workspace.xml" afterPath="$PROJECT_DIR$/.idea/workspace.xml" />
-      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/example.yml" afterPath="$PROJECT_DIR$/example.yml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/protocols/osi1-2/arp.yml" afterPath="$PROJECT_DIR$/protocols/osi1-2/arp.yml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/protocols/osi1-2/eth-frame.yml" afterPath="$PROJECT_DIR$/protocols/osi1-2/eth-frame.yml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/protocols/osi1-2/eth-packet.yml" afterPath="$PROJECT_DIR$/protocols/osi1-2/eth-packet.yml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/protocols/osi3/icmpv4.yml" afterPath="$PROJECT_DIR$/protocols/osi3/icmpv4.yml" />
+      <change type="MODIFICATION" beforePath="$PROJECT_DIR$/protocols/osi3/ipv4.yml" afterPath="$PROJECT_DIR$/protocols/osi3/ipv4.yml" />
       <change type="MODIFICATION" beforePath="$PROJECT_DIR$/schema.yml" afterPath="$PROJECT_DIR$/schema.yml" />
       <change type="MODIFICATION" beforePath="$PROJECT_DIR$/validate.py" afterPath="$PROJECT_DIR$/validate.py" />
     </list>
@@ -29,10 +32,10 @@
       <file leaf-file-name="validate.py" pinned="false" current-in-tab="true">
         <entry file="file://$PROJECT_DIR$/validate.py">
           <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="216">
-              <caret line="12" column="33" selection-start-line="12" selection-start-column="33" selection-end-line="12" selection-end-column="33" />
+            <state relative-caret-position="410">
+              <caret line="39" column="43" selection-start-line="39" selection-start-column="43" selection-end-line="39" selection-end-column="43" />
               <folding>
-                <element signature="e#1#11#0" expanded="true" />
+                <element signature="e#0#10#0" expanded="true" />
               </folding>
             </state>
           </provider>
@@ -130,7 +133,7 @@
   </component>
   <component name="PropertiesComponent">
     <property name="last_opened_file_path" value="$PROJECT_DIR$" />
-    <property name="settings.editor.selected.configurable" value="com.jetbrains.python.configuration.PyActiveSdkModuleConfigurable" />
+    <property name="settings.editor.selected.configurable" value="preferences.keymap" />
     <property name="settings.editor.splitter.proportion" value="0.2" />
   </component>
   <component name="RunManager" selected="Python.validate">
@@ -147,7 +150,7 @@
       <option name="ADD_SOURCE_ROOTS" value="true" />
       <module name="npd" />
       <option name="SCRIPT_NAME" value="$PROJECT_DIR$/validate.py" />
-      <option name="PARAMETERS" value="example.yml" />
+      <option name="PARAMETERS" value="--all -v" />
       <option name="SHOW_COMMAND_LINE" value="false" />
       <method />
     </configuration>
@@ -285,8 +288,26 @@
       <option name="USE_KEYWORD" value="false" />
       <method />
     </configuration>
-    <list size="1">
-      <item index="0" class="java.lang.String" itemvalue="Python.validate" />
+    <configuration default="false" name="validate single file" type="PythonConfigurationType" factoryName="Python">
+      <option name="INTERPRETER_OPTIONS" value="" />
+      <option name="PARENT_ENVS" value="true" />
+      <envs>
+        <env name="PYTHONUNBUFFERED" value="1" />
+      </envs>
+      <option name="SDK_HOME" value="" />
+      <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$" />
+      <option name="IS_MODULE_SDK" value="true" />
+      <option name="ADD_CONTENT_ROOTS" value="true" />
+      <option name="ADD_SOURCE_ROOTS" value="true" />
+      <module name="npd" />
+      <option name="SCRIPT_NAME" value="$PROJECT_DIR$/validate.py" />
+      <option name="PARAMETERS" value="-f example.yml" />
+      <option name="SHOW_COMMAND_LINE" value="false" />
+      <method />
+    </configuration>
+    <list size="2">
+      <item index="0" class="java.lang.String" itemvalue="Python.validate single file" />
+      <item index="1" class="java.lang.String" itemvalue="Python.validate" />
     </list>
     <recent_temporary>
       <list size="1">
@@ -351,7 +372,7 @@
         <state relative-caret-position="0">
           <caret line="0" column="0" selection-start-line="0" selection-start-column="0" selection-end-line="0" selection-end-column="0" />
           <folding>
-            <element signature="e#1#11#0" expanded="true" />
+            <element signature="e#0#10#0" expanded="true" />
           </folding>
         </state>
       </provider>
@@ -361,7 +382,7 @@
         <state relative-caret-position="234">
           <caret line="14" column="25" selection-start-line="14" selection-start-column="25" selection-end-line="14" selection-end-column="25" />
           <folding>
-            <element signature="e#1#11#0" expanded="true" />
+            <element signature="e#0#10#0" expanded="true" />
           </folding>
         </state>
       </provider>
@@ -378,7 +399,7 @@
         <state relative-caret-position="234">
           <caret line="14" column="25" selection-start-line="14" selection-start-column="25" selection-end-line="14" selection-end-column="25" />
           <folding>
-            <element signature="e#1#11#0" expanded="true" />
+            <element signature="e#0#10#0" expanded="true" />
           </folding>
         </state>
       </provider>
@@ -395,7 +416,7 @@
         <state relative-caret-position="234">
           <caret line="14" column="25" selection-start-line="14" selection-start-column="25" selection-end-line="14" selection-end-column="25" />
           <folding>
-            <element signature="e#1#11#0" expanded="true" />
+            <element signature="e#0#10#0" expanded="true" />
           </folding>
         </state>
       </provider>
@@ -439,10 +460,10 @@
     </entry>
     <entry file="file://$PROJECT_DIR$/validate.py">
       <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="216">
-          <caret line="12" column="33" selection-start-line="12" selection-start-column="33" selection-end-line="12" selection-end-column="33" />
+        <state relative-caret-position="410">
+          <caret line="39" column="43" selection-start-line="39" selection-start-column="43" selection-end-line="39" selection-end-column="43" />
           <folding>
-            <element signature="e#1#11#0" expanded="true" />
+            <element signature="e#0#10#0" expanded="true" />
           </folding>
         </state>
       </provider>
diff --git a/protocols/osi3/icmpv4.yml b/protocols/osi3/icmpv4.yml
index 6ede820..bf7df2b 100644
--- a/protocols/osi3/icmpv4.yml
+++ b/protocols/osi3/icmpv4.yml
@@ -15,4 +15,5 @@ protocol: &icmpv4
       desc: rest of header
       length: 4
     - field: data
-      optional: true
\ No newline at end of file
+      data: true
+      optional: true
diff --git a/schema.yml b/schema.yml
index d7473fc..0fe18c5 100644
--- a/schema.yml
+++ b/schema.yml
@@ -26,12 +26,16 @@ definitions:
   field:
     type: object
     properties:
+      length:
+        type: integer
+      reflength:
+        type: string
+      data:
+        type: boolean
       field:
         type: string
       desc:
         type: string
-      length:
-        type: integer
       bitfield:
         type: boolean
       optional:
@@ -40,16 +44,18 @@ definitions:
         type: boolean
       nextlayer:
         type: boolean
-      data:
-        type: boolean
       reference:
         type: string
-      reflength:
-        type: string
       subfields:
         type: array
         items:
           $ref: "#/definitions/field"
+    oneOf:
+      - required:
+        - length
+      - required:
+        - reflength
+      - required:
+        - data
     required:
       - field
-      - length
diff --git a/validate.py b/validate.py
index bc1dadb..c4eb597 100644
--- a/validate.py
+++ b/validate.py
@@ -1,24 +1,46 @@
-
 import sys
 from jsonschema import validate
 import yaml
-
+import argparse
+import glob
 
 
 def main(argv):
-    schemafile = "schema.yml"
-    schema = None
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--all", help="Validate all protocols.", action="store_true")
+    parser.add_argument("-f", help="Validate file.", default=None)
+    parser.add_argument("-s", help="Use schema file.", default="schema.yml")
+    parser.add_argument("-v", help="Verbosity...", action="store_true")
+    args = parser.parse_args()
+    schemafile = args.s
     schemadata = None
     with open(schemafile, "r") as f:
         schemadata = yaml.load(f)
-    data = None
-    with open(argv[1], "r") as f:
-        data = yaml.load(f)
-    # get all yml files from protocols
-    # validate with
-    validate(data, schemadata)
+    if args.all:
+        # search for files and validate them.
+        print("Validating all files in protocols/osi*")
+        list = glob.glob("protocols/osi*/*.yml", recursive=True)
+        for file in list:
+            print("Validating file: " + file)
+            validateFile(file, schemadata, True if args.v else False)
+        pass
+    elif args.f is not None:
+        validateFile(args.f, schemadata, True if args.v else False)
+        pass
 
 
+def validateFile(file, schema, verbose=False):
+    data = None
+    with open(file, "r") as f:
+        data = yaml.load(f)
+    try:
+        validate(data, schema)
+        print(file + " is valid.")
+    except:
+        print("Failed to validate: " + file)
+        if verbose:
+            raise
+
 
 if __name__ == '__main__':
     main(sys.argv)