Re: [libvirt PATCH 2/3] conf: add an attribute to turn on NAT for IPv6 virtual networks

Historically IPv6 did not support NAT, so when IPv6 was added to libvirt's virtual networks, when requesting <forward mode="nat"/> libvirt will NOT apply NAT to IPv6 traffic, only IPv4 traffic. This is an annoying historical design decision as it means we cannot enable IPv6 automatically. We thus need to introduce a new attribute <forward mode="nat"> <nat ipv6="yes"/> </forward> The new attribute is a tri-state, so it leaves open the possibility of us intentionally changing the default behaviour in future to honour NAT for IPv6. Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- docs/formatnetwork.html.in | 14 ++++++++++ docs/schemas/network.rng | 8 ++++++ src/conf/network_conf.c | 26 +++++++++++++++++-- src/conf/network_conf.h | 2 ++ .../nat-network-forward-nat-ipv6.xml | 10 +++++++ .../nat-network-forward-nat-ipv6.xml | 11 ++++++++ tests/networkxml2xmltest.c | 1 + 7 files changed, 70 insertions(+), 2 deletions(-) create mode 100644 tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml create mode 100644 tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in index 0383e2d891..42cfb6708a 100644 --- a/docs/formatnetwork.html.in +++ b/docs/formatnetwork.html.in @@ -276,6 +276,20 @@ &lt;/nat&gt; &lt;/forward&gt; ...</pre> + + <p> + <span class="since">Since 6.5.0</span> it is possible to + enable NAT with IPv6 networking. As noted above, IPv6 + has historically done plain forwarding and thus to avoid + breaking historical compatibility, IPv6 NAT must be + explicitly requested

+ </p> + <pre> +... + &lt;forward mode='nat'&gt; + &lt;nat ipv6='yes'/&gt; + &lt;/forward&gt; +...</pre> </dd> <dt><code>route</code></dt> diff --git a/docs/schemas/network.rng b/docs/schemas/network.rng index 88b6f4dfdd..d9448fa3bb 100644 --- a/docs/schemas/network.rng +++ b/docs/schemas/network.rng @@ -181,6 +181,14 @@ </optional> <optional> <element name='nat'> + <optional> + <attribute name="ipv6"> + <choice> + <value>yes</value> + <value>no</value> + </choice> + </attribute>

+ </optional> <interleave> <optional> <element name='address'> diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c index f1d22b25b1..cd7683e94b 100644 --- a/src/conf/network_conf.c +++ b/src/conf/network_conf.c @@ -1358,6 +1358,7 @@ virNetworkForwardNatDefParseXML(const char *networkName, int nNatAddrs, nNatPorts; char *addrStart = NULL; char *addrEnd = NULL; + char *ipv6 = NULL; VIR_XPATH_NODE_AUTORESTORE(ctxt); ctxt->node = node; @@ -1369,6 +1370,19 @@ virNetworkForwardNatDefParseXML(const char *networkName, goto cleanup; } + ipv6 = virXMLPropString(node, "ipv6"); + if (ipv6) { + if ((def->natIPv6 + = virTristateBoolTypeFromString(ipv6)) <= 0) {

+ virReportError(VIR_ERR_XML_ERROR, + _("Invalid ipv6 setting '%s' " + "in network '%s' NAT"), + ipv6, networkName); + goto cleanup; + } + VIR_FREE(ipv6); + } + /* addresses for SNAT */ nNatAddrs = virXPathNodeSet("./address", ctxt, &natAddrNodes); if (nNatAddrs < 0) { @@ -2516,10 +2530,18 @@ virNetworkForwardNatDefFormat(virBufferPtr buf, goto cleanup; } - if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end) + if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end && !fwd->natIPv6)

return 0; - virBufferAddLit(buf, "<nat>\n"); + virBufferAddLit(buf, "<nat"); + if (fwd->natIPv6) + virBufferAsprintf(buf, " ipv6='%s'", virTristateBoolTypeToString(fwd->natIPv6)); + + if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end) { + virBufferAddLit(buf, "/>\n"); + return 0; + }

+ virBufferAddLit(buf, ">\n"); virBufferAdjustIndent(buf, 2); if (addrStart) { diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h index f2dc388ef0..e3a61c62ea 100644 --- a/src/conf/network_conf.h +++ b/src/conf/network_conf.h @@ -244,6 +244,8 @@ struct _virNetworkForwardDef { /* ranges for NAT */ virSocketAddrRange addr; virPortRange port; + + virTristateBool natIPv6; }; typedef struct _virPortGroupDef virPortGroupDef; diff --git a/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml b/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml new file mode 100644 index 0000000000..c3b641224c --- /dev/null +++ b/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml @@ -0,0 +1,10 @@ +<network> + <name>default</name> + <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid> + <bridge name="virbr0"/> + <forward mode="nat" dev="eth1"> + <nat ipv6="yes"/> + </forward> + <ip family="ipv6" address="2001:db8:ac10:fe01::1" prefix="64"> + </ip> +</network> diff --git a/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml b/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml new file mode 100644 index 0000000000..74e1c36c69 --- /dev/null +++ b/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml @@ -0,0 +1,11 @@ +<network> + <name>default</name> + <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid> + <forward dev='eth1' mode='nat'> + <nat ipv6='yes'/> + <interface dev='eth1'/>

+ </forward> + <bridge name='virbr0' stp='on' delay='0'/> + <ip family='ipv6' address='2001:db8:ac10:fe01::1' prefix='64'> + </ip> +</network> diff --git a/tests/networkxml2xmltest.c b/tests/networkxml2xmltest.c index 700744785a..17817418b7 100644 --- a/tests/networkxml2xmltest.c +++ b/tests/networkxml2xmltest.c @@ -140,6 +140,7 @@ mymain(void) DO_TEST("nat-network-dns-forward-plain"); DO_TEST("nat-network-dns-forwarders"); DO_TEST("nat-network-dns-forwarder-no-resolv"); + DO_TEST("nat-network-forward-nat-ipv6"); DO_TEST("nat-network-forward-nat-address"); DO_TEST("nat-network-forward-nat-no-address"); DO_TEST("nat-network-mtu");