Re: [libvirt] [PATCH v2] Fix dnsmasq/radvd on bridges not being able to be bound to IPv6 address on "recent" kernels

Le mercredi 20 juin 2012 à 11:05 +0100, Daniel P. Berrange a écrit : > I think you also need to have a VIR_FOFRCE_CLOSE(tapfd) in the > very last of the cleanup jump labels. Since between the time > we open the tapfd & close it, we might have done a 'goto err1' > or similar. Yes, I forgot that. New patch following. > Looks reasonable apart from the cleanup bug. Thanks. BTW, if this patch is commited, I'm already in AUTHORS under another email address, which is OK. --- src/network/bridge_driver.c | 22 ++++++++++++++++++++-- src/uml/uml_conf.c | 2 +- src/util/virnetdevtap.c | 24 ++++++++++++++---------- src/util/virnetdevtap.h | 2 ++ 4 files changed, 37 insertions(+), 13 deletions(-) diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 79d3010..e9f3c90 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -62,6 +62,7 @@ #include "virnetdev.h" #include "virnetdevbridge.h" #include "virnetdevtap.h" +#include "virfile.h" #define NETWORK_PID_DIR LOCALSTATEDIR "/run/libvirt/network" #define NETWORK_STATE_DIR LOCALSTATEDIR "/lib/libvirt/network" @@ -840,6 +841,7 @@ networkStartRadvd(virNetworkObjPtr network) " AdvSendAdvert on;\n" " AdvManagedFlag off;\n" " AdvOtherConfigFlag off;\n" + " IgnoreIfMissing on;\n" "\n", network->def->bridge); for (ii = 0; @@ -1744,6 +1746,7 @@ networkStartNetworkVirtual(struct network_driver *driver, virErrorPtr save_err = NULL; virNetworkIpDefPtr ipdef; char *macTapIfName = NULL; + int tapfd = -1; /* Check to see if any network IP collides with an existing route */ if (networkCheckRouteCollision(network) < 0) @@ -1765,10 +1768,13 @@ networkStartNetworkVirtual(struct network_driver *driver, virReportOOMError(); goto err0; } + /* Keep tun fd open and interface up to allow for IPv6 DAD to happen */ if (virNetDevTapCreateInBridgePort(network->def->bridge, &macTapIfName, network->def->mac, - NULL, NULL, NULL, - VIR_NETDEV_TAP_CREATE_USE_MAC_FOR_BRIDGE) < 0) { + NULL, &tapfd, NULL, + VIR_NETDEV_TAP_CREATE_USE_MAC_FOR_BRIDGE + |VIR_NETDEV_TAP_CREATE_IFUP + |VIR_NETDEV_TAP_CREATE_PERSIST) < 0) { VIR_FREE(macTapIfName); goto err0; } @@ -1828,6 +1834,16 @@ networkStartNetworkVirtual(struct network_driver *driver, if (v6present && networkStartRadvd(network) < 0) goto err4; + /* DAD has happened (dnsmasq waits for it), dnsmasq is now bound to the + * bridge's IPv6 address, and radvd to the interface, so we can now set the + * dummy tun down. + */ + if (tapfd >= 0) { + if (virNetDevSetOnline(macTapIfName, false) < 0) + goto err4; + VIR_FORCE_CLOSE(tapfd); + } + if (virNetDevBandwidthSet(network->def->bridge, network->def->bandwidth) < 0) { networkReportError(VIR_ERR_INTERNAL_ERROR, _("cannot set bandwidth limits on %s"), @@ -1866,6 +1882,8 @@ networkStartNetworkVirtual(struct network_driver *driver, save_err = virSaveLastError(); if (macTapIfName) { + if (tapfd >= 0) + VIR_FORCE_CLOSE(tapfd); ignore_value(virNetDevTapDelete(macTapIfName)); VIR_FREE(macTapIfName); } diff --git a/src/uml/uml_conf.c b/src/uml/uml_conf.c index 79b249d..c9b5044 100644 --- a/src/uml/uml_conf.c +++ b/src/uml/uml_conf.c @@ -141,7 +141,7 @@ umlConnectTapDevice(virConnectPtr conn, if (virNetDevTapCreateInBridgePort(bridge, &net->ifname, net->mac, vm->uuid, NULL, virDomainNetGetActualVirtPortProfile(net), - VIR_NETDEV_TAP_CREATE_IFUP) < 0) { + VIR_NETDEV_TAP_CREATE_IFUP|VIR_NETDEV_TAP_CREATE_PERSIST) < 0) { if (template_ifname) VIR_FREE(net->ifname); goto error; diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c index 5d21164..45ff20f 100644 --- a/src/util/virnetdevtap.c +++ b/src/util/virnetdevtap.c @@ -118,18 +118,20 @@ virNetDevProbeVnetHdr(int tapfd) * * VIR_NETDEV_TAP_CREATE_VNET_HDR * - Enable IFF_VNET_HDR on the tap device + * VIR_NETDEV_TAP_CREATE_PERSIST + * - The device will persist after the file descriptor is closed * * Creates a tap interface. - * If the @tapfd parameter is supplied, the open tap device file - * descriptor will be returned, otherwise the TAP device will be made - * persistent and closed. The caller must use virNetDevTapDelete to - * remove a persistent TAP devices when it is no longer needed. + * If the @tapfd parameter is supplied, the open tap device file descriptor + * will be returned, otherwise the TAP device will be closed. The caller must + * use virNetDevTapDelete to remove a persistent TAP device when it is no + * longer needed. * * Returns 0 in case of success or an errno code in case of failure. */ int virNetDevTapCreate(char **ifname, int *tapfd, - unsigned int flags ATTRIBUTE_UNUSED) + unsigned int flags) { int fd; struct ifreq ifr; @@ -166,7 +168,7 @@ int virNetDevTapCreate(char **ifname, goto cleanup; } - if (!tapfd && + if ((flags & VIR_NETDEV_TAP_CREATE_PERSIST) && (errno = ioctl(fd, TUNSETPERSIST, 1))) { virReportSystemError(errno, _("Unable to set tap device %s to persistent"), @@ -267,14 +269,16 @@ int virNetDevTapDelete(const char *ifname ATTRIBUTE_UNUSED) * - Enable IFF_VNET_HDR on the tap device * VIR_NETDEV_TAP_CREATE_USE_MAC_FOR_BRIDGE * - Set this interface's MAC as the bridge's MAC address + * VIR_NETDEV_TAP_CREATE_PERSIST + * - The device will persist after the file descriptor is closed * * This function creates a new tap device on a bridge. @ifname can be either * a fixed name or a name template with '%d' for dynamic name allocation. * in either case the final name for the bridge will be stored in @ifname. - * If the @tapfd parameter is supplied, the open tap device file - * descriptor will be returned, otherwise the TAP device will be made - * persistent and closed. The caller must use virNetDevTapDelete to remove - * a persistent TAP devices when it is no longer needed. + * If the @tapfd parameter is supplied, the open tap device file descriptor + * will be returned, otherwise the TAP device will be closed. The caller must + * use virNetDevTapDelete to remove a persistent TAP device when it is no + * longer needed. * * Returns 0 in case of success or -1 on failure */ diff --git a/src/util/virnetdevtap.h b/src/util/virnetdevtap.h index d9a3593..f1355ba 100644 --- a/src/util/virnetdevtap.h +++ b/src/util/virnetdevtap.h @@ -42,6 +42,8 @@ typedef enum { VIR_NETDEV_TAP_CREATE_VNET_HDR = 1 << 1, /* Set this interface's MAC as the bridge's MAC address */ VIR_NETDEV_TAP_CREATE_USE_MAC_FOR_BRIDGE = 1 << 2, + /* The device will persist after the file descriptor is closed */ + VIR_NETDEV_TAP_CREATE_PERSIST = 1 << 3, } virNetDevTapCreateFlags; int virNetDevTapCreateInBridgePort(const char *brname,