[libvirt] [PATCH 02/10] conf: Network - add ability to read/write XML DHCP state

From: "TJ" <libvirt(a)iam.tj&gt; Maintain backwards XML compatibility by assuming existing default values and only adding the additional XML properties if settings are not default. Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/conf/network_conf.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c index 3fc01cf..259de0a 100644 --- a/src/conf/network_conf.c +++ b/src/conf/network_conf.c @@ -828,6 +828,19 @@ virNetworkDHCPDefParseXML(const char *networkName, { xmlNodePtr cur; + char *tmp = NULL; + + def->dhcp_enabled = true; + if ((tmp = virXMLPropString(node, "enabled"))) { + def->dhcp_enabled = strncmp("no", tmp, 2) == 0 ? false : def->dhcp_enabled; + VIR_FREE(tmp); + } + + def->dhcp_relay = false; + if ((tmp = virXMLPropString(node, "relay"))) { + def->dhcp_relay = strncmp("yes", tmp, 3) == 0 ? true : def->dhcp_relay; + VIR_FREE(tmp); + } cur = node->children; while (cur != NULL) { @@ -2180,12 +2193,19 @@ virNetworkIpDefFormat(virBufferPtr buf, virBufferEscapeString(buf, "<tftp root='%s' />\n", def->tftproot); } - if ((def->nranges || def->nhosts)) { + if ((def->nranges || def->nhosts) || + !def->dhcp_enabled || def->dhcp_relay) { int ii; - virBufferAddLit(buf, "<dhcp>\n"); + virBufferAddLit(buf, "<dhcp"); + if (!def->dhcp_enabled) + virBufferAddLit(buf, " enabled='no'"); + if (def->dhcp_relay) + virBufferAddLit(buf, " relay='yes'"); + virBufferAddLit(buf, ">\n"); + virBufferAdjustIndent(buf, 2); - for (ii = 0 ; ii < def->nranges ; ii++) { + for (ii = 0 ; def->nranges && ii < def->nranges ; ii++) { char *saddr = virSocketAddrFormat(&def->ranges[ii].start); if (!saddr) goto error; @@ -2199,7 +2219,7 @@ virNetworkIpDefFormat(virBufferPtr buf, VIR_FREE(saddr); VIR_FREE(eaddr); } - for (ii = 0 ; ii < def->nhosts ; ii++) { + for (ii = 0 ; def->nhosts && ii < def->nhosts ; ii++) { virBufferAddLit(buf, "<host "); if (def->hosts[ii].mac) virBufferAsprintf(buf, "mac='%s' ", def->hosts[ii].mac); -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 17:11:52 +0000 Subject: [PATCH 03/10] conf: Network - add pointers to enabled virNetworkIpDef DHCP settings To: libvir-list(a)redhat.com Having previously introduced DHCP enabled and relay state within the virNetworkIpDef structure - which can be one of many on each network - these pointers allow us to track and easily access the DHCP state for IPv4 and IPv6 when setting up the network without having to iterate every virNetworkIpDef to find the DHCP state. Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/conf/network_conf.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h index 8400eab..1889c45 100644 --- a/src/conf/network_conf.h +++ b/src/conf/network_conf.h @@ -231,6 +231,8 @@ struct _virNetworkDef { virPortGroupDefPtr portGroups; virNetDevBandwidthPtr bandwidth; virNetDevVlan vlan; + virNetworkIpDefPtr ipv4_dhcp; + virNetworkIpDefPtr ipv6_dhcp; }; typedef struct _virNetworkObj virNetworkObj; -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 17:14:36 +0000 Subject: [PATCH 04/10] conf: Network - keep track of active DHCP stanza in virNetworkDef To: libvir-list(a)redhat.com To avoid iterating all virNetworkIpDef entries when determining DHCP state keep track of the first enabled DHCP stanza in the network definition itself, for both IPv4 and IPv6. A by-product of this change is it allows the XML to contain more than one IP->DHCP stanza. The active DHCP stanza is the first enabled DHCP stanza. All other stanzas are retained which adds flexibility when multiple interfaces and routes might come and go since an alternative DHCP stanza can be selected and a refresh operation performed without needing to destroy/edit/start the network. Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/conf/network_conf.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c index 259de0a..c5eab01 100644 --- a/src/conf/network_conf.c +++ b/src/conf/network_conf.c @@ -1882,6 +1882,13 @@ virNetworkDefParseXML(xmlXPathContextPtr ctxt) if (ret < 0) goto error; def->nips++; + /* use only the first enabled DHCP definition */ + if (!def->ipv4_dhcp && def->ips[ii].dhcp_enabled && + VIR_SOCKET_ADDR_IS_FAMILY(&def->ips[ii].address, AF_INET)) + def->ipv4_dhcp = &def->ips[ii]; + if (!def->ipv6_dhcp && def->ips[ii].dhcp_enabled && + VIR_SOCKET_ADDR_IS_FAMILY(&def->ips[ii].address, AF_INET6)) + def->ipv6_dhcp = &def->ips[ii]; } } VIR_FREE(ipNodes); -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 17:43:46 +0000 Subject: [PATCH 05/10] network: Bridge - use IPv4 and IPv6 active DHCP stanza pointers To: libvir-list(a)redhat.com Rather than iterate through virNetworkIPDef arrays multiple times use the new virNetworkDef ipv4_dhcp and ipv6_dhcp active stanza pointers. Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/network/bridge_driver.c | 63 +++++++++++---------------------------------- 1 file changed, 15 insertions(+), 48 deletions(-) diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 0932cf8..8410c93 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -810,24 +810,16 @@ networkDnsmasqConfContents(virNetworkObjPtr network, } } - /* Find the first dhcp for both IPv4 and IPv6 */ - for (ii = 0, ipv4def = NULL, ipv6def = NULL, ipv6SLAAC = false; - (ipdef = virNetworkDefGetIpByIndex(network->def, AF_UNSPEC, ii)); - ii++) { - if (VIR_SOCKET_ADDR_IS_FAMILY(&ipdef->address, AF_INET)) { - if (ipdef->nranges || ipdef->nhosts) { - if (ipv4def) { - virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", - _("For IPv4, multiple DHCP definitions " - "cannot be specified.")); - goto cleanup; - } else { - ipv4def = ipdef; - } - } - } - if (VIR_SOCKET_ADDR_IS_FAMILY(&ipdef->address, AF_INET6)) { - if (ipdef->nranges || ipdef->nhosts) { + ipv4def = ipv6def = NULL; + ipdef = network->def->ipv4_dhcp; + if (ipdef && (ipdef->nranges || ipdef->nhosts)) + ipv4def = ipdef; + + ipdef = network->def->ipv6_dhcp; + if (ipdef) { + if (ipdef->nranges || ipdef->nhosts) { + ipv6def = ipdef; + if (!DNSMASQ_DHCPv6_SUPPORT(caps)) { unsigned long version = dnsmasqCapsGetVersion(caps); virReportError(VIR_ERR_CONFIG_UNSUPPORTED, @@ -842,18 +834,9 @@ networkDnsmasqConfContents(virNetworkObjPtr network, DNSMASQ_DHCPv6_MINOR_REQD); goto cleanup; } - if (ipv6def) { - virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", - _("For IPv6, multiple DHCP definitions " - "cannot be specified.")); - goto cleanup; - } else { - ipv6def = ipdef; - } - } else { - ipv6SLAAC = true; - } - } + } + } else { + ipv6SLAAC = true; } if (ipv6def && ipv6SLAAC) { @@ -1160,25 +1143,9 @@ networkRefreshDhcpDaemon(struct network_driver *driver, if (!(dctx = dnsmasqContextNew(network->def->name, DNSMASQ_STATE_DIR))) goto cleanup; - /* Look for first IPv4 address that has dhcp defined. - * We only support dhcp-host config on one IPv4 subnetwork - * and on one IPv6 subnetwork. - */ - ipv4def = NULL; - for (ii = 0; - (ipdef = virNetworkDefGetIpByIndex(network->def, AF_INET, ii)); - ii++) { - if (!ipv4def && (ipdef->nranges || ipdef->nhosts)) - ipv4def = ipdef; - } + ipv4def = network->def->ipv4_dhcp; - ipv6def = NULL; - for (ii = 0; - (ipdef = virNetworkDefGetIpByIndex(network->def, AF_INET6, ii)); - ii++) { - if (!ipv6def && (ipdef->nranges || ipdef->nhosts)) - ipv6def = ipdef; - } + ipv6def = network->def->ipv6_dhcp; if (ipv4def && (networkBuildDnsmasqDhcpHostsList(dctx, ipv4def) < 0)) goto cleanup; -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 20:26:58 +0000 Subject: [PATCH 06/10] network: Bridge - Add support for a DHCP Relay Agent To: libvir-list(a)redhat.com A DHCP relay daemon will be started that will forward all DHCP/BOOTP requests on the bridge network via the first declared forward interface. The relay is broadcast rather than routed so no IP address is needed on the bridge. The XML <relay> element's "relay" property of the active DHCP stanza defaults to 'no'. Set it to 'yes' to enable the relay: <ip ...> <dhcp relay='yes'/> </ip> The relay will not be started if the "enable" property is 'no': <ip ...> <dhcp enable='no' relay='yes'/> </ip> Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/network/bridge_driver.c | 146 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 8410c93..c02d3de 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -587,6 +587,145 @@ cleanup: * which is later saved into a file */ +static virNetworkIpDefPtr +networkGetActiveDhcp(virNetworkObjPtr network) +{ + virNetworkIpDefPtr dhcp = NULL; + + if (network->def && network->def->ipv4_dhcp) + dhcp = network->def->ipv4_dhcp; + + if (!dhcp && + network->def && network->def->ipv6_dhcp) + dhcp = network->def->ipv6_dhcp; + + return dhcp; +} + +static int +networkBuildDhcpRelayArgv(virNetworkObjPtr network, + const char *pidfile, + virCommandPtr cmd) +{ + int ret = -1; + + /* PID file */ + virCommandAddArgList(cmd, "-r", pidfile, NULL); + + /* Listen for DHCP requests on the bridge interface */ + virCommandAddArgList(cmd, "-i", network->def->bridge, NULL); + + /* Use the first forwarding device to broadcast to the upstream DHCP server */ + if (network->def->forward.nifs > 0) { + virCommandAddArgList(cmd, "-b", network->def->forward.ifs[0].device.dev, NULL); + ret = 0; + } else + virReportSystemError(VIR_ERR_INVALID_INTERFACE, + _("DHCP relay requires at least one network %s\n"), + "<forward ... dev='eth?'/> or <interface dev='eth?'/>"); + + return ret; +} + +static int +networkBuildDhcpRelayCommandLine(virNetworkObjPtr network, virCommandPtr *cmdout, + char *pidfile) +{ + virCommandPtr cmd = NULL; + int ret = -1; + + cmd = virCommandNew(DHCPRELAY); + if (networkBuildDhcpRelayArgv(network, pidfile, cmd) < 0) { + goto cleanup; + } + + if (cmdout) + *cmdout = cmd; + ret = 0; +cleanup: + if (ret < 0) + virCommandFree(cmd); + return ret; +} + +static int +networkStartDhcpRelayDaemon(struct network_driver *driver ATTRIBUTE_UNUSED, + virNetworkObjPtr network) +{ + virCommandPtr cmd = NULL; + virNetworkIpDefPtr ipdef = NULL; + char *pidfile = NULL; + char *tmp = NULL; + int pid_len; + int ret = 0; + const char *dhcprelay = "dhcprelay_"; + + ipdef = networkGetActiveDhcp(network); + /* Prepare for DHCP relay agent */ + if (ipdef && ipdef->dhcp_enabled && ipdef->dhcp_relay) { + ret = -1; + + if (virFileMakePath(NETWORK_PID_DIR) < 0) { + virReportSystemError(errno, + _("cannot create directory %s"), + NETWORK_PID_DIR); + goto cleanup; + } + + pid_len = strlen(dhcprelay) + strlen(network->def->name); + if ( VIR_ALLOC_N(tmp, pid_len+1) >= 0) { + tmp = strcpy(tmp, dhcprelay); + tmp = strncat(tmp, network->def->name, pid_len); + if (!(pidfile = virPidFileBuildPath(NETWORK_PID_DIR, tmp))) { + virReportOOMError(); + goto cleanup; + } + } else { + virReportOOMError(); + goto cleanup; + } + + ret = networkBuildDhcpRelayCommandLine(network, &cmd, pidfile); + if (ret < 0) + goto cleanup; + + ret = virCommandRun(cmd, NULL); + if (ret < 0) + goto cleanup; + + ret = virPidFileRead(NETWORK_PID_DIR, pidfile, &network->dhcprelayPid); + if (ret < 0) + virReportSystemError(errno, _("%s is not running"), DHCPRELAY); + +cleanup: + VIR_FREE(tmp); + VIR_FREE(pidfile); + virCommandFree(cmd); + } + return ret; +} + +static int +networkRestartDhcpRelayDaemon(struct network_driver *driver, + virNetworkObjPtr network) +{ + /* if there is a running DHCP relay agent, kill it */ + if (network->dhcprelayPid > 0) { + networkKillDaemon(network->dhcprelayPid, DHCPRELAY, + network->def->name); + network->dhcprelayPid = -1; + } + /* now start the daemon if it should be started */ + return networkStartDhcpRelayDaemon(driver, network); +} + +static int +networkRefreshDhcpRelayDaemon(struct network_driver *driver, + virNetworkObjPtr network) +{ + return networkRestartDhcpRelayDaemon(driver, network); +} + static int networkBuildDnsmasqDhcpHostsList(dnsmasqContext *dctx, virNetworkIpDefPtr ipdef) @@ -1496,6 +1635,7 @@ networkRefreshDaemons(struct network_driver *driver) * dnsmasq and/or radvd, or restart them if they've * disappeared. */ + networkRefreshDhcpRelayDaemon(driver, network); networkRefreshDhcpDaemon(driver, network); networkRefreshRadvd(driver, network); } @@ -2462,6 +2602,10 @@ networkStartNetworkVirtual(struct network_driver *driver, networkStartDhcpDaemon(driver, network) < 0) goto err3; + /* start DHCP relay-agent (doesn't need IP address(es) to function) */ + if (networkStartDhcpRelayDaemon(driver, network) < 0) + goto err3; + /* start radvd if there are any ipv6 addresses */ if (v6present && networkStartRadvd(driver, network) < 0) goto err4; @@ -3276,6 +3420,8 @@ networkUpdate(virNetworkPtr net, */ if (networkRestartDhcpDaemon(driver, network) < 0) goto cleanup; + if (networkRestartDhcpRelayDaemon(driver, network) < 0) + goto cleanup; } else if (section == VIR_NETWORK_SECTION_IP_DHCP_HOST) { /* if we previously weren't listening for dhcp and now we -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 21:22:47 +0000 Subject: [PATCH 07/10] network: Bridge - don't offer dnsmasq DHCP services when DHCP relay is enabled To: libvir-list(a)redhat.com When dnsmasq's DNS services are required but the network is configured to use a DHCP relay agent (other than dnsmasq's proxy services) the configuration generated for dnsmasq should not enable DHCP services. Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/network/bridge_driver.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index c02d3de..a4cd727 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -951,11 +951,12 @@ networkDnsmasqConfContents(virNetworkObjPtr network, ipv4def = ipv6def = NULL; ipdef = network->def->ipv4_dhcp; - if (ipdef && (ipdef->nranges || ipdef->nhosts)) + if (ipdef && ipdef->dhcp_enabled && !ipdef->dhcp_relay && + (ipdef->nranges || ipdef->nhosts)) ipv4def = ipdef; ipdef = network->def->ipv6_dhcp; - if (ipdef) { + if (ipdef && ipdef->dhcp_enabled && !ipdef->dhcp_relay) { if (ipdef->nranges || ipdef->nhosts) { ipv6def = ipdef; @@ -1266,8 +1267,8 @@ static int networkRefreshDhcpDaemon(struct network_driver *driver, virNetworkObjPtr network) { - int ret = -1, ii; - virNetworkIpDefPtr ipdef, ipv4def, ipv6def; + int ret = -1; + virNetworkIpDefPtr ipv4def, ipv6def; dnsmasqContext *dctx = NULL; /* if no IP addresses specified, nothing to do */ -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Tue, 26 Feb 2013 21:35:05 +0000 Subject: [PATCH 08/10] configure: Add DHCPRELAY to the set of external program definitions To: libvir-list(a)redhat.com This variable should name the path to the system's DHCP relay daemon. At this time the expected daemon is "dhcp-helper", a DHCP relay agent from Simon Kelly, author of dnsmasq. The supporting code, however, has been designed to work with any suitable DHCP relay agent. Later patches could allow configuration of the agent's command-line arguments. Currently the chosen agent must support: -b <bridge_interface> (the virtual network to listen on) -i <physical_interface> (the interface to broadcast on) -r </path/to/pid.file> (the PID file of the daemon) Signed-off-by: TJ <linux(a)iam.tj&gt; --- configure.ac | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/configure.ac b/configure.ac index e3a749a..b62170e 100644 --- a/configure.ac +++ b/configure.ac @@ -295,6 +295,8 @@ dnl External programs that we can use if they are available. dnl We will hard-code paths to these programs unless we cannot dnl detect them, in which case we'll search for the program dnl along the $PATH at runtime and fail if it's not there. +AC_PATH_PROG([DHCPRELAY], [dhcp-helper], [dhcp-helper], + [/sbin:/usr/sbin:/usr/local/sbin:$PATH]) AC_PATH_PROG([DNSMASQ], [dnsmasq], [dnsmasq], [/sbin:/usr/sbin:/usr/local/sbin:$PATH]) AC_PATH_PROG([RADVD], [radvd], [radvd], @@ -314,6 +316,8 @@ AC_PATH_PROG([OVSVSCTL], [ovs-vsctl], [ovs-vsctl], AC_PATH_PROG([SCRUB], [scrub], [scrub], [/sbin:/usr/sbin:/usr/local/sbin:$PATH]) +AC_DEFINE_UNQUOTED([DHCPRELAY], ["$DHCPRELAY"], + [Location or name of the dhcp relay-agent program]) AC_DEFINE_UNQUOTED([DNSMASQ],["$DNSMASQ"], [Location or name of the dnsmasq program]) AC_DEFINE_UNQUOTED([RADVD],["$RADVD"], -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Wed, 27 Feb 2013 03:51:28 +0000 Subject: [PATCH 09/10] Add copyright attribution for DHCP relay functionality To: libvir-list(a)redhat.com Signed-off-by: TJ <linux(a)iam.tj&gt; --- src/conf/network_conf.c | 1 + src/network/bridge_driver.c | 1 + 2 files changed, 2 insertions(+) diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c index c5eab01..43c277c 100644 --- a/src/conf/network_conf.c +++ b/src/conf/network_conf.c @@ -3,6 +3,7 @@ * * Copyright (C) 2006-2013 Red Hat, Inc. * Copyright (C) 2006-2008 Daniel P. Berrange + * Copyright (C) 2013 TJ <linux(a)iam.tj&gt; * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index a4cd727..1667ae6 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -4,6 +4,7 @@ * * Copyright (C) 2006-2013 Red Hat, Inc. * Copyright (C) 2006 Daniel P. Berrange + * Copyright (C) 2013 TJ <linux(a)iam.tj&gt; * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public -- 1.8.1.2.433.g9808ce0.dirty In-Reply-To: <512E724A.10805(a)iam.tj&gt; References: <512E724A.10805(a)iam.tj&gt; From: "TJ" <libvirt(a)iam.tj&gt; Date: Wed, 27 Feb 2013 20:35:06 +0000 Subject: [PATCH 10/10] docs: Describe the <dhcp> 'enable' and 'relay' attributes To: libvir-list(a)redhat.com Signed-off-by: TJ <linux(a)iam.tj&gt; --- docs/formatnetwork.html.in | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in index 41a83fa..c4c4def 100644 --- a/docs/formatnetwork.html.in +++ b/docs/formatnetwork.html.in @@ -650,12 +650,20 @@ <dt><code>dhcp</code></dt> <dd>Also within the <code>ip</code> element there is an optional <code>dhcp</code> element. The presence of this element - enables DHCP services on the virtual network. It will further + enables DHCP services on the virtual network. It can further contain one or more <code>range</code> elements. The <code>dhcp</code> element supported for both IPv4 <span class="since">Since 0.3.0</span> and IPv6 <span class="since">Since 1.0.1</span>, but only for one IP address of each type per network. + Since $TODO.$FIXME it can optionally contain a boolean <code>enable</code> attribute + ('yes' or 'no') where the value defaults to 'yes', and a boolean + <code>relay</code> attribute where the value defaults to 'no'. + When <code>relay='yes'</code> any settings within the <code>dhcp</code> block + are ignored and a DHCP relay agent is started instead of a local DHCP server. + The DHCP relay daemon will listen on the network's bridge interface for + DHCP/BOOTP traffic and relay it via broadcast from the first interface declared + in the <code>forward</code> element. <dl> <dt><code>range</code></dt> <dd>The <code>start</code> and <code>end</code> attributes on the @@ -779,6 +787,18 @@ &lt;ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" /&gt; &lt;/network&gt;</pre> + <p>Here is the same configuration using a DHCP relay agent instead of a local DHCP server.</p> + <pre> + &lt;network&gt; + &lt;name&gt;local&lt;/name&gt; + &lt;bridge name="virbr1" /&gt; + &lt;forward mode="route" dev="eth1"/&gt; + &lt;ip address="192.168.122.1" netmask="255.255.255.0"&gt; + &lt;dhcp relay='yes'/&gt; + &lt;/ip&gt; + &lt;ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" /&gt; + &lt;/network&gt;</pre> + <p> Below is another IPv6 varition. Instead of a dhcp range being specified, this example has a couple of IPv6 host definitions. -- 1.8.1.2.433.g9808ce0.dirty