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[libvirt] [PATCH 2/2] use client id for IPv6 DHCP host definition



Originally, only a host name was used to associate a
DHCPv6 request with a specific IPv6 address.  Further testing
demonstrates that this is an unreliable method and, instead,
a client-id or DUID needs to be used.  According to DHCPv6
standards, this id can be a duid-LLT, duid-LL, or duid-UUID
even though dnsmasq will accept almost any text string.

Although validity checking of a specified string makes sure it is
hexadecimal notation with bytes separated by colons, there is no
rigorous check to make sure it meets the standard.

Documentation and schemas have been updated.
Signed-off-by: Gene Czarcinski <gene czarc net>
---
 docs/formatnetwork.html.in                         | 18 ++++++-
 docs/schemas/basictypes.rng                        | 59 ++++++++++++++++++++++
 docs/schemas/network.rng                           |  3 ++
 src/conf/network_conf.c                            | 29 +++++++++--
 src/conf/network_conf.h                            |  1 +
 src/network/bridge_driver.c                        |  3 +-
 src/util/virdnsmasq.c                              | 20 ++++++--
 src/util/virdnsmasq.h                              |  1 +
 tests/networkxml2confdata/dhcp6-nat-network.xml    |  5 +-
 tests/networkxml2confdata/dhcp6-network.xml        |  5 +-
 .../dhcp6host-routed-network.xml                   |  5 +-
 11 files changed, 135 insertions(+), 14 deletions(-)

diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
index 7b42529..94391d7 100644
--- a/docs/formatnetwork.html.in
+++ b/docs/formatnetwork.html.in
@@ -749,6 +749,11 @@
     <p>
       Below is another IPv6 varition.  Instead of a dhcp range being
       specified, this example has a couple of IPv6 host definitions.
+      Note that most of the dhcp host definitions use an "id" (client
+      id or DUID) since this has proven to be a more reliable way
+      of specifying the interface and its association with an IPv6
+      address.  The first is a DUID-LLT, the second a DUID-LL, and
+      the third a DUID-UUID.  <span class="since">Since 1.0.3</span>
     </p>
 
     <pre>
@@ -764,7 +769,9 @@
         &lt;ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" &gt;
           &lt;dhcp&gt;
             &lt;host name="paul"   ip="2001:db8:ca2:2:3::1" /&gt;
-            &lt;host name="bob"    ip="2001:db8:ca2:2:3::2" /&gt;
+            &lt;host id="0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66"    ip="2001:db8:ca2:2:3::2" /&gt;
+            &lt;host id="0:3:0:1:0:16:3e:11:22:33" name="ralph"  ip="2001:db8:ca2:2:3::3" /&gt;
+            &lt;host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="badbob" ip="2001:db8:ca2:2:3::4" /&gt;
           &lt;/dhcp&gt;
         &lt;/ip&gt;
       &lt;/network&gt;</pre>
@@ -795,6 +802,11 @@
 
     <p>
       This variation of an isolated network defines only IPv6.
+      Note that most of the dhcp host definitions use an "id" (client
+      id or DUID) since this has proven to be a more reliable way
+      of specifying the interface and its association with an IPv6
+      address.  The first is a DUID-LLT, the second a DUID-LL, and
+      the third a DUID-UUID.  <span class="since">Since 1.0.3</span>
     </p>
 
     <pre>
@@ -804,7 +816,9 @@
         &lt;ip family="ipv6" address="2001:db8:ca2:6::1" prefix="64" &gt;
           &lt;dhcp&gt;
             &lt;host name="peter"   ip="2001:db8:ca2:6:6::1" /&gt;
-            &lt;host name="dariusz" ip="2001:db8:ca2:6:6::2" /&gt;
+            &lt;host id="0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66" ip="2001:db8:ca2:6:6::2" /&gt;
+            &lt;host id="0:3:0:1:0:16:3e:11:22:33" name="dariusz" ip="2001:db8:ca2:6:6::3" /&gt;
+            &lt;host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="anita" ip="2001:db8:ca2:6:6::4" /&gt;
           &lt;/dhcp&gt;
         &lt;/ip&gt;
       &lt;/network&gt;</pre>
diff --git a/docs/schemas/basictypes.rng b/docs/schemas/basictypes.rng
index 2d2f442..5e2a333 100644
--- a/docs/schemas/basictypes.rng
+++ b/docs/schemas/basictypes.rng
@@ -101,6 +101,65 @@
     </data>
   </define>
 
+  <!--====================================================================-->
+  <!--The duid is a unique identifier used in DHCPv6 to identity an       -->
+  <!--interface on a device (system).  The duid is often used by servers  -->
+  <!--such as dnsmasq to assign a specific IP address (and optionally a   -->
+  <!--name to an interface.  The applicable standards are RFC3315 and     -->
+  <!--RFC6355.  These standards actualy require the duid to be fixed for  -->
+  <!--the hardward device and applicable to all network interfaces on     -->
+  <!--that device.  It is not clear that any software currently enforces  -->
+  <!--this requirement although it could be implemented manually.         -->
+  <!--====================================================================-->
+  <!--There are currently four types of duids defined:                    -->
+  <!--  type 1, duid-LLT, link-layer (MAC) plus 32 bit time when the      -->
+  <!--          duid-LLT was created in seconds from January 1, 2000      -->
+  <!--  type 2, duid-EN, 32 bit "enterprise number" followed by a         -->
+  <!--          variable length unique identifier.                        -->
+  <!--  type 3, duid-LL, link-layer (MAC)                                 -->
+  <!--  type 4, duid-UUID, a 128 bit UUID (16 bytes)                      -->
+  <!--RFC3315 states that the maximum length of a duid is 128 bytes plus  -->
+  <!--the 16 bit type field.  Often, the machine type is "1" which is the -->
+  <!--number assigned to ethernet.                                        -->
+
+  <define name="duidLLT">
+    <data type="string">
+                     <!--   0======| type======| 0======| machine type======| time================| link-layer============|     -->
+      <param name="pattern">[0]{1,2}:[0]{0,1}[1]:[0]{1,2}:[0]{0,1}[a-fA-F1-9](:[a-fA-F0-9]{1,2}){4}(:[a-fA-F0-9]{1,2}){6,8}</param>
+    </data>
+  </define>
+
+  <define name="duidEN">
+    <data type="string">
+                     <!--   0======| type======| Enterprise number===| unique id ==============|     -->
+      <param name="pattern">[0]{1,2}:[0]{0,1}[2](:[a-fA-F0-9]{1,2}){4}(:[a-fA-F0-9]{1,2}){1,124}</param>
+    </data>
+  </define>
+
+  <define name="duidLL">
+    <data type="string">
+                     <!--   0======| type======| 0======| machine type======| link-layer============|     -->
+      <param name="pattern">[0]{1,2}:[0]{0,1}[3]:[0]{1,2}:[0]{0,1}[a-fA-F1-9](:[a-fA-F0-9]{1,2}){6,8}</param>
+    </data>
+  </define>
+
+  <define name="duidUUID">
+    <data type="string">
+                     <!--   0======| type======| UUID=================|     -->
+      <param name="pattern">[0]{1,2}:[0]{0,1}[4](:[a-fA-F0-9]{1,2}){16}</param>
+    </data>
+  </define>
+
+  <define name="DUID">
+    <choice>
+      <ref name="duidLLT"/>
+      <ref name="duidEN"/>
+      <ref name="duidLL"/>
+      <ref name="duidUUID"/>
+    </choice>
+  </define>
+  <!--======================================================================-->
+
   <!-- An ipv4 "dotted quad" address -->
   <define name="ipv4Addr">
     <data type="string">
diff --git a/docs/schemas/network.rng b/docs/schemas/network.rng
index a479453..98be9d6 100644
--- a/docs/schemas/network.rng
+++ b/docs/schemas/network.rng
@@ -279,6 +279,9 @@
                 <zeroOrMore>
                   <element name="host">
                     <optional>
+                      <attribute name="id"><ref name="DUID"/></attribute>
+                    </optional>
+                    <optional>
                       <attribute name="mac"><ref name="uniMacAddr"/></attribute>
                     </optional>
                     <optional>
diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index c93916d..7848a52 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -118,6 +118,7 @@ static void
 virNetworkDHCPHostDefClear(virNetworkDHCPHostDefPtr def)
 {
     VIR_FREE(def->mac);
+    VIR_FREE(def->id);
     VIR_FREE(def->name);
 }
 
@@ -678,7 +679,7 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
                               virNetworkDHCPHostDefPtr host,
                               bool partialOkay)
 {
-    char *mac = NULL, *name = NULL, *ip = NULL;
+    char *mac = NULL, *name = NULL, *ip = NULL, *id = NULL;
     virMacAddr addr;
     virSocketAddr inaddr;
     int ret = -1;
@@ -707,10 +708,25 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
         }
     }
 
+    id = virXMLPropString(node, "id");
+    if (id) {
+        char *cp = id;
+
+        while (*cp) {
+            if ((*cp != ':') && (!c_isxdigit(*cp))) {
+                virReportError(VIR_ERR_XML_ERROR,
+                               _("Cannot use id '%s' in network '%s'"),
+                               id, networkName);
+                goto cleanup;
+            }
+            cp++;
+        }
+    }
+
     name = virXMLPropString(node, "name");
     if (name && (!c_isalpha(name[0]))) {
         virReportError(VIR_ERR_XML_ERROR,
-                       _("Cannot use name address '%s' in network '%s'"),
+                       _("Cannot use host name '%s' in network '%s'"),
                        name, networkName);
         goto cleanup;
     }
@@ -738,10 +754,10 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
          * address or name (IPv4)
          */
         if (VIR_SOCKET_ADDR_IS_FAMILY(&def->address, AF_INET6)) {
-            if (!name) {
+            if (!(id || name)) {
                 virReportError(VIR_ERR_XML_ERROR,
                            _("Static host definition in IPv6 network '%s' "
-                             "must have name attribute"),
+                             "must have id or name attribute"),
                            networkName);
                 goto cleanup;
             }
@@ -763,6 +779,8 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
 
     host->mac = mac;
     mac = NULL;
+    host->id = id;
+    id = NULL;
     host->name = name;
     name = NULL;
     if (ip)
@@ -771,6 +789,7 @@ virNetworkDHCPHostDefParseXML(const char *networkName,
 
 cleanup:
     VIR_FREE(mac);
+    VIR_FREE(id);
     VIR_FREE(name);
     VIR_FREE(ip);
     return ret;
@@ -2020,6 +2039,8 @@ virNetworkIpDefFormat(virBufferPtr buf,
             virBufferAddLit(buf, "<host ");
             if (def->hosts[ii].mac)
                 virBufferAsprintf(buf, "mac='%s' ", def->hosts[ii].mac);
+            if (def->hosts[ii].id)
+                virBufferAsprintf(buf, "id='%s' ", def->hosts[ii].id);
             if (def->hosts[ii].name)
                 virBufferAsprintf(buf, "name='%s' ", def->hosts[ii].name);
             if (VIR_SOCKET_ADDR_VALID(&def->hosts[ii].ip)) {
diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h
index 4c634ed..48d8718 100644
--- a/src/conf/network_conf.h
+++ b/src/conf/network_conf.h
@@ -73,6 +73,7 @@ typedef struct _virNetworkDHCPHostDef virNetworkDHCPHostDef;
 typedef virNetworkDHCPHostDef *virNetworkDHCPHostDefPtr;
 struct _virNetworkDHCPHostDef {
     char *mac;
+    char *id;
     char *name;
     virSocketAddr ip;
 };
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 21255f0..6c41f55 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -599,7 +599,8 @@ networkBuildDnsmasqDhcpHostsList(dnsmasqContext *dctx,
     for (i = 0; i < ipdef->nhosts; i++) {
         virNetworkDHCPHostDefPtr host = &(ipdef->hosts[i]);
         if (VIR_SOCKET_ADDR_VALID(&host->ip))
-            if (dnsmasqAddDhcpHost(dctx, host->mac, &host->ip, host->name, ipv6) < 0)
+            if (dnsmasqAddDhcpHost(dctx, host->mac, &host->ip,
+                                   host->name, host->id, ipv6) < 0)
                 return -1;
     }
 
diff --git a/src/util/virdnsmasq.c b/src/util/virdnsmasq.c
index 6637a89..98ad5cd 100644
--- a/src/util/virdnsmasq.c
+++ b/src/util/virdnsmasq.c
@@ -303,6 +303,7 @@ hostsfileAdd(dnsmasqHostsfile *hostsfile,
              const char *mac,
              virSocketAddr *ip,
              const char *name,
+             const char *id,
              bool ipv6)
 {
     char *ipstr = NULL;
@@ -314,9 +315,19 @@ hostsfileAdd(dnsmasqHostsfile *hostsfile,
 
     /* the first test determines if it is a dhcpv6 host */
     if (ipv6) {
-        if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,[%s]",
-                        name, ipstr) < 0)
-            goto alloc_error;
+        if (name && id) {
+            if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "id:%s,%s,[%s]",
+                            id, name, ipstr) < 0)
+                goto alloc_error;
+        } else if (name && !id) {
+            if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,[%s]",
+                            name, ipstr) < 0)
+                goto alloc_error;
+        } else if (!name && id) {
+            if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "id:%s,[%s]",
+                            id, ipstr) < 0)
+                goto alloc_error;
+        }
     }
     else if (name && mac) {
         if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,%s,%s",
@@ -511,9 +522,10 @@ dnsmasqAddDhcpHost(dnsmasqContext *ctx,
                    const char *mac,
                    virSocketAddr *ip,
                    const char *name,
+                   const char *id,
                    bool ipv6)
 {
-    return hostsfileAdd(ctx->hostsfile, mac, ip, name, ipv6);
+    return hostsfileAdd(ctx->hostsfile, mac, ip, name, id, ipv6);
 }
 
 /*
diff --git a/src/util/virdnsmasq.h b/src/util/virdnsmasq.h
index a97d3e6..ed560da 100644
--- a/src/util/virdnsmasq.h
+++ b/src/util/virdnsmasq.h
@@ -86,6 +86,7 @@ int              dnsmasqAddDhcpHost(dnsmasqContext *ctx,
                                     const char *mac,
                                     virSocketAddr *ip,
                                     const char *name,
+                                    const char *id,
                                     bool ipv6);
 int              dnsmasqAddHost(dnsmasqContext *ctx,
                                 virSocketAddr *ip,
diff --git a/tests/networkxml2confdata/dhcp6-nat-network.xml b/tests/networkxml2confdata/dhcp6-nat-network.xml
index 72103f7..4259173 100644
--- a/tests/networkxml2confdata/dhcp6-nat-network.xml
+++ b/tests/networkxml2confdata/dhcp6-nat-network.xml
@@ -15,8 +15,11 @@
   <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
     <dhcp>
       <range start='2001:db8:ac10:fd01::1:10' end='2001:db8:ac10:fd01::1:ff' />
-      <host name='ralph' ip='2001:db8:ac10:fd01::1:20' />
+      <host id='0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63' ip='2001:db8:ac10:fd01::1:20' />
       <host name='paul' ip='2001:db8:ac10:fd01::1:21' />
+      <host id='0:3:0:1:0:16:3e:11:22:33' name='peter.xyz' ip='2001:db8:ac10:fd01::1:22' />
+      <host id='0:3:0:1:0:16:3e:44:55:33' ip='2001:db8:ac10:fd01::1:23' />
+      <host id='0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66' name='badbob' ip='2001:db8:ac10:fd01::1:24' />
     </dhcp>
   </ip>
   <ip family='ipv4' address='10.24.10.1'>
diff --git a/tests/networkxml2confdata/dhcp6-network.xml b/tests/networkxml2confdata/dhcp6-network.xml
index 311013a..776737e 100644
--- a/tests/networkxml2confdata/dhcp6-network.xml
+++ b/tests/networkxml2confdata/dhcp6-network.xml
@@ -7,8 +7,11 @@
   <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
     <dhcp>
       <range start='2001:db8:ac10:fd01::1:10' end='2001:db8:ac10:fd01::1:ff' />
-      <host name='ralph' ip='2001:db8:ac10:fd01::1:20' />
+      <host id='0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63' ip='2001:db8:ac10:fd01::1:20' />
       <host name='paul' ip='2001:db8:ac10:fd01::1:21' />
+      <host id='0:3:0:1:0:16:3e:11:22:33' name='peter.xyz' ip='2001:db8:ac10:fd01::1:22' />
+      <host id='0:3:0:1:0:16:3e:44:55:33' ip='2001:db8:ac10:fd01::1:23' />
+      <host id='0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66' name='badbob' ip='2001:db8:ac10:fd01::1:24' />
     </dhcp>
   </ip>
 </network>
diff --git a/tests/networkxml2confdata/dhcp6host-routed-network.xml b/tests/networkxml2confdata/dhcp6host-routed-network.xml
index 38d9ebf..2693d87 100644
--- a/tests/networkxml2confdata/dhcp6host-routed-network.xml
+++ b/tests/networkxml2confdata/dhcp6host-routed-network.xml
@@ -12,8 +12,11 @@
   </ip>
   <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
     <dhcp>
-      <host name='ralph' ip='2001:db8:ac10:fd01::1:20' />
+      <host id='0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63' ip='2001:db8:ac10:fd01::1:20' />
       <host name='paul' ip='2001:db8:ac10:fd01::1:21' />
+      <host id='0:3:0:1:0:16:3e:11:22:33' name='peter.xyz' ip='2001:db8:ac10:fd01::1:22' />
+      <host id='0:3:0:1:0:16:3e:44:55:33' ip='2001:db8:ac10:fd01::1:23' />
+      <host id='0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66' name='badbob' ip='2001:db8:ac10:fd01::1:24' />
     </dhcp>
   </ip>
 </network>
-- 
1.8.1.2


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