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



On 02/15/2013 02:02 PM, Gene Czarcinski wrote:
> 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++;

Instead of a loop, you could just do something like

    char *cp = id + strcspn(id, "0123456789abcdefABCDEF:");
    if (*cp) {
        virReportError(VIR_ERR_XML_ERROR,
                       _("Invalid character '%c' in id '%s' of network
'%s'"),
                       *cp, id, networkName);
    }

> +        }
> +    }
> +
>      name = virXMLPropString(node, "name");
>      if (name && (!c_isalpha(name[0]))) {

Hmm. This isn't a change of this patch, but that check could do with a
bit more validation in a separate patch. While the first character must
be alpha, all characters after that must be alphanumeric, "-", or ".".


>          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;
> +        }

Heh. There might be a more compact way to express all those options, but
it would probably just make it confusing to follow :-)

>      }
>      else if (name && mac) {

Although it's not really related, this might be a good chance to move
this else up to the same line as the preceding {.


>          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>

Other than the suggestion to use strcspn() instead of a while loop, this
all looks fine to me. ACK with that change made. If you (or someone
else) wants to ACK the short interdiff I've attached that makes that
change, I'll push it.


>From 0b2f2f0794e931af901bc31e4fe6eadc799bee33 Mon Sep 17 00:00:00 2001
From: Laine Stump <laine laine org>
Date: Mon, 18 Feb 2013 21:33:49 -0500
Subject: [PATCH] Changes to squash into "use client id for IPv6 DHCP host
 definition"

---
 src/conf/network_conf.c | 15 +++++----------
 src/util/virdnsmasq.c   |  3 +--
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index 8657284..12bf4d7 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -710,16 +710,11 @@ 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++;
+        char *cp = id + strcspn(id, "0123456789abcdefABCDEF:");
+        if (*cp) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("Invalid character '%c' in id '%s' of network '%s'"),
+                           *cp, id, networkName);
         }
     }
 
diff --git a/src/util/virdnsmasq.c b/src/util/virdnsmasq.c
index 98ad5cd..f2b57a8 100644
--- a/src/util/virdnsmasq.c
+++ b/src/util/virdnsmasq.c
@@ -328,8 +328,7 @@ hostsfileAdd(dnsmasqHostsfile *hostsfile,
                             id, ipstr) < 0)
                 goto alloc_error;
         }
-    }
-    else if (name && mac) {
+    } else if (name && mac) {
         if (virAsprintf(&hostsfile->hosts[hostsfile->nhosts].host, "%s,%s,%s",
                         mac, ipstr, name) < 0)
             goto alloc_error;
-- 
1.7.11.7


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