bandwidth: Define schema and create documentation

Define new 'bandwidth' element with possible child element 'inbound'
and 'outbound' addressing incoming and outgoing traffic respectively:

<bandwidth>
  <inbound average='1000' peak='2000' burst='5120'/>
  <outbound average='500'/>
</bandwidth>

Leaving any element out means not to shape traffic in that
direction.
The units for average and peak (rate) are in kilobytes per second,
for burst (size) are just in kilobytes.
This element can be inserted into domain's 'interface' and
'network'.

docs/formatdomain.html.in

@@ -1882,6 +1882,40 @@ qemu-kvm -net nic,model=? /dev/null
       <span class="since">Since 0.8.8</span>
     </p>
 
+    <h5><a name="elementQoS">Quality of service</a></h5>
+
+<pre>
+  ...
+  &lt;devices&gt;
+    &lt;interface type='network'&gt;
+      &lt;source network='default'/&gt;
+      &lt;target dev='vnet0'/&gt;
+      <b>&lt;bandwidth&gt;
+        &lt;inbound average='1000' peak='5000' burst='1024'/&gt;
+        &lt;outbound average='128' peak='256' burst='256'/&gt;
+      &lt;/bandwidth&gt;</b>
+    &lt;/interface&gt;
+  &lt;devices&gt;
+  ...</pre>
+
+    <p>
+      This part of interface XML provides setting quality of service. Incoming
+      and outgoing traffic can be shaped independently. The
+      <code>bandwidth</code> element can have at most one <code>inbound</code>
+      and at most one <code>outbound</code> child elements. Leaving any of these
+      children element out result in no QoS applied on that traffic direction.
+      So, when you want to shape only domain's incoming traffic, use
+      <code>inbound</code> only, and vice versa. Each of these elements have one
+      mandatory attribute <code>average</code>. It specifies average bit rate on
+      interface being shaped. Then there are two optional attributes:
+      <code>peak</code>, which specifies maximum rate at which interface can send
+      data, and <code>burst</code>, amount of bytes that can be burst at
+      <code>peak</code> speed. Accepted values for attributes are integer
+      numbers. The units for <code>average</code> and <code>peak</code> attributes
+      are kilobytes per second, and for the <code>burst</code> just kilobytes.
+      <span class="since">Since 0.9.4</span>
+    </p>
+
     <h4><a name="elementsInput">Input devices</a></h4>
 
     <p>

docs/formatnetwork.html.in

@@ -101,6 +101,36 @@
         to this host. <span class="since">Since 0.3.0; 'mode' attribute since
         0.4.2</span></dd>
     </dl>
+    <h5><a name="elementQoS">Quality of service</a></h5>
+
+<pre>
+...
+  &lt;forward mode='nat' dev='eth0'/&gt;
+  <b>&lt;bandwidth&gt;
+    &lt;inbound average='1000' peak='5000' burst='5120'/&gt;
+    &lt;outbound average='128' peak='256' burst='256'/&gt;
+  &lt;/bandwidth&gt;</b>
+  &lt;mac address='00:16:3E:5D:C7:9E'/&gt;
+...</pre>
+
+      <p>
+        This part of network XML provides setting quality of service. Incoming
+        and outgoing traffic can be shaped independently. The
+        <code>bandwidth</code> element can have at most one <code>inbound</code>
+        and at most one <code>outbound</code> child elements. Leaving any of these
+        children element out result in no QoS applied on that traffic direction.
+        So, when you want to shape only network's incoming traffic, use
+        <code>inbound</code> only, and vice versa. Each of these elements have one
+        mandatory attribute <code>average</code>. It specifies average bit rate on
+        interface being shaped. Then there are two optional attributes:
+        <code>peak</code>, which specifies maximum rate at which bridge can send
+        data, and <code>burst</code>, amount of bytes that can be burst at
+        <code>peak</code> speed. Accepted values for attributes are integer
+        numbers, The units for <code>average</code> and <code>peak</code> attributes
+        are kilobytes per second, and for the <code>burst</code> just kilobytes.
+        The rate is shared equally within domains connected to the network.
+        <span class="since">Since 0.9.4</span>
+      </p>
 
     <h3><a name="elementsAddress">Addressing</a></h3>
 

docs/schemas/domain.rng

@@ -1189,6 +1189,9 @@
       <optional>
         <ref name="deviceBoot"/>
       </optional>
+      <optional>
+        <ref name="bandwidth"/>
+      </optional>
     </interleave>
   </define>
   <!--

docs/schemas/network.rng

@@ -147,6 +147,9 @@
               </zeroOrMore>
             </element>
         </optional>
+       <optional>
+         <ref name="bandwidth"/>
+       </optional>
 
         <!-- <ip> element -->
         <zeroOrMore>

docs/schemas/networkcommon.rng

@@ -47,4 +47,52 @@
       </group>
     </choice>
   </define>
+
+  <define name="bandwidth">
+    <element name="bandwidth">
+      <interleave>
+        <optional>
+          <element name="inbound">
+            <ref name="bandwidth-attributes"/>
+            <empty/>
+          </element>
+        </optional>
+        <optional>
+          <element name="outbound">
+            <ref name="bandwidth-attributes"/>
+            <empty/>
+          </element>
+        </optional>
+      </interleave>
+    </element>
+  </define>
+
+  <define name="bandwidth-attributes">
+    <attribute name="average">
+      <ref name="speed"/>
+    </attribute>
+    <optional>
+      <attribute name="peak">
+        <ref name="speed"/>
+      </attribute>
+    </optional>
+    <optional>
+      <attribute name='burst'>
+        <ref name="BurstSize"/>
+      </attribute>
+    </optional>
+  </define>
+
+  <define name="speed">
+    <data type="unsignedInt">
+      <param name="pattern">[0-9]+</param>
+      <param name="minInclusive">1</param>
+    </data>
+  </define>
+  <define name="BurstSize">
+    <data type="unsignedInt">
+      <param name="pattern">[0-9]+</param>
+      <param name="minInclusive">1</param>
+    </data>
+  </define>
 </grammar>