From cbd8227ee0578bffa9b94a62cb037552501e986f Mon Sep 17 00:00:00 2001 From: Dirk Herrendoerfer Date: Tue, 21 Jun 2011 11:49:40 -0400 Subject: [PATCH] set and restore MAC address of a NIC when using PASSTHROUGH mode The following patch addresses the problem that when a PASSTHROUGH mode DIRECT NIC connection is made the MAC address of the NIC is not automatically set and reset to the configured VM MAC and back again. The attached patch fixes this problem by setting and resetting the MAC while remembering the previous setting while the VM is running. This also works if libvirtd is restarted while the VM is running. the patch passes make syntax-check --- src/libvirt_private.syms | 2 + src/qemu/qemu_command.c | 6 +- src/qemu/qemu_hotplug.c | 4 +- src/qemu/qemu_process.c | 3 +- src/util/interface.c | 96 +++++++++++++++++++++++++++++++ src/util/interface.h | 4 ++ src/util/macvtap.c | 121 ++++++++++++++++++++++++++++++++++++++- src/util/macvtap.h | 7 ++- 8 files changed, 235 insertions(+), 8 deletions(-) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 8e844e9df4..09b01592ef 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -498,7 +498,9 @@ ifaceCheck; ifaceCtrl; ifaceGetFlags; ifaceGetIndex; +ifaceGetMacaddr; ifaceGetVlanID; +ifaceSetMacaddr; ifaceIsUp; diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 6346243320..e9ca1c9f93 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -128,7 +128,7 @@ qemuPhysIfaceConnect(virDomainDefPtr def, rc = openMacvtapTap(net->ifname, net->mac, net->data.direct.linkdev, net->data.direct.mode, vnet_hdr, def->uuid, &net->data.direct.virtPortProfile, &res_ifname, - vmop); + vmop, driver->stateDir); if (rc >= 0) { qemuAuditNetDevice(def, net, res_ifname, true); VIR_FREE(net->ifname); @@ -149,7 +149,9 @@ qemuPhysIfaceConnect(virDomainDefPtr def, if (err) { VIR_FORCE_CLOSE(rc); delMacvtap(net->ifname, net->mac, net->data.direct.linkdev, - &net->data.direct.virtPortProfile); + net->data.direct.mode, + &net->data.direct.virtPortProfile, + driver->stateDir); VIR_FREE(net->ifname); } } diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index e805849760..a7f11ab436 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -1610,7 +1610,9 @@ int qemuDomainDetachNetDevice(struct qemud_driver *driver, #if WITH_MACVTAP if (detach->type == VIR_DOMAIN_NET_TYPE_DIRECT) { delMacvtap(detach->ifname, detach->mac, detach->data.direct.linkdev, - &detach->data.direct.virtPortProfile); + detach->data.direct.mode, + &detach->data.direct.virtPortProfile, + driver->stateDir); VIR_FREE(detach->ifname); } #endif diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index 8e09e52fad..b4411376a2 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -2876,7 +2876,8 @@ void qemuProcessStop(struct qemud_driver *driver, virDomainNetDefPtr net = def->nets[i]; if (net->type == VIR_DOMAIN_NET_TYPE_DIRECT) { delMacvtap(net->ifname, net->mac, net->data.direct.linkdev, - &net->data.direct.virtPortProfile); + net->data.direct.mode, + &net->data.direct.virtPortProfile, driver->stateDir); VIR_FREE(net->ifname); } } diff --git a/src/util/interface.c b/src/util/interface.c index 04a922c939..7651f1d1a6 100644 --- a/src/util/interface.c +++ b/src/util/interface.c @@ -390,3 +390,99 @@ ifaceGetVlanID(const char *vlanifname ATTRIBUTE_UNUSED, return ENOSYS; } #endif /* __linux__ */ + +/** + * ifaceGetMacaddr: + * @ifname: interface name to set MTU for + * @macaddr: MAC address (VIR_MAC_BUFLEN in size) + * + * This function gets the @macaddr for a given interface @ifname. + * + * Returns 0 in case of success or an errno code in case of failure. + */ +#ifdef __linux__ +int +ifaceGetMacaddr(const char *ifname, + unsigned char *macaddr) +{ + struct ifreq ifr; + int fd; + + if (!ifname) + return EINVAL; + + fd = socket(AF_INET, SOCK_STREAM, 0); + if (fd < 0) + return errno; + + memset(&ifr, 0, sizeof(struct ifreq)); + if (virStrcpyStatic(ifr.ifr_name, ifname) == NULL) + return EINVAL; + + if (ioctl(fd, SIOCGIFHWADDR, (char *)&ifr) != 0) + return errno; + + memcpy(macaddr, ifr.ifr_ifru.ifru_hwaddr.sa_data, VIR_MAC_BUFLEN); + + return 0; +} + +#else + +int +ifaceGetMacaddr(const char *ifname ATTRIBUTE_UNUSED, + unsigned char *macaddr ATTRIBUTE_UNUSED) +{ + return ENOSYS; +} + +#endif /* __linux__ */ + +/** + * ifaceSetMacaddr: + * @ifname: interface name to set MTU for + * @macaddr: MAC address (VIR_MAC_BUFLEN in size) + * + * This function sets the @macaddr for a given interface @ifname. This + * gets rid of the kernel's automatically assigned random MAC. + * + * Returns 0 in case of success or an errno code in case of failure. + */ +#ifdef __linux__ +int +ifaceSetMacaddr(const char *ifname, + const unsigned char *macaddr) +{ + struct ifreq ifr; + int fd; + + if (!ifname) + return EINVAL; + + fd = socket(AF_INET, SOCK_STREAM, 0); + if (fd < 0) + return errno; + + memset(&ifr, 0, sizeof(struct ifreq)); + if (virStrcpyStatic(ifr.ifr_name, ifname) == NULL) + return EINVAL; + + /* To fill ifr.ifr_hdaddr.sa_family field */ + if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0) + return errno; + + memcpy(ifr.ifr_hwaddr.sa_data, macaddr, VIR_MAC_BUFLEN); + + return ioctl(fd, SIOCSIFHWADDR, &ifr) == 0 ? 0 : errno; +} + +#else + +int +ifaceSetMacaddr(const char *ifname ATTRIBUTE_UNUSED, + const unsigned char *macaddr ATTRIBUTE_UNUSED) +{ + return ENOSYS; +} + +#endif /* __linux__ */ diff --git a/src/util/interface.h b/src/util/interface.h index 6470492041..fc0611b4d7 100644 --- a/src/util/interface.h +++ b/src/util/interface.h @@ -32,4 +32,8 @@ int ifaceGetIndex(bool reportError, const char *ifname, int *ifindex); int ifaceGetVlanID(const char *vlanifname, int *vlanid); +int ifaceSetMacaddr(const char *ifname, const unsigned char *macaddr); + +int ifaceGetMacaddr(const char *ifname, unsigned char *macaddr); + #endif /* __VIR_INTERFACE_H__ */ diff --git a/src/util/macvtap.c b/src/util/macvtap.c index 068638e71b..48c7b0ebe7 100644 --- a/src/util/macvtap.c +++ b/src/util/macvtap.c @@ -545,6 +545,103 @@ configMacvtapTap(int tapfd, int vnet_hdr) return 0; } +/** + * replaceMacAdress: + * @macaddress: new MAC address for interface + * @linkdev: name of interface + * @stateDir: directory to store old MAC address + * + * Returns 0 on success, -1 in case of fatal error, error code otherwise. + * + */ +static int +replaceMacAdress(const unsigned char *macaddress, + const char *linkdev, + char *stateDir) +{ + unsigned char oldmac[6]; + int rc; + + rc = ifaceGetMacaddr(linkdev, oldmac); + + if (rc) { + virReportSystemError(rc, + _("Getting MAC address from '%s' " + "to '%02x:%02x:%02x:%02x:%02x:%02x' failed."), + linkdev, + oldmac[0], oldmac[1], oldmac[2], + oldmac[3], oldmac[4], oldmac[5]); + } else { + char *path = NULL; + char macstr[VIR_MAC_STRING_BUFLEN]; + + if (virAsprintf(&path, "%s/%s", + stateDir, + linkdev) < 0) { + virReportOOMError(); + return errno; + } + virFormatMacAddr(oldmac, macstr); + if (virFileWriteStr(path, macstr, O_CREAT|O_TRUNC|O_WRONLY) < 0) { + virReportSystemError(errno, _("Unable to preserve mac for %s"), + linkdev); + return errno; + } + } + + rc = ifaceSetMacaddr(linkdev, macaddress); + if (rc) { + virReportSystemError(errno, + _("Setting MAC address on '%s' to " + "'%02x:%02x:%02x:%02x:%02x:%02x' failed."), + linkdev, + macaddress[0], macaddress[1], macaddress[2], + macaddress[3], macaddress[4], macaddress[5]); + } + return rc; +} + +/** + * restoreMacAddress: + * @linkdev: name of interface + * @stateDir: directory containing old MAC address + * + * Returns 0 on success, -1 in case of fatal error, error code otherwise. + * + */ +static int +restoreMacAddress(const char *linkdev, + char *stateDir) +{ + char *oldmacname = NULL; + char *macstr = NULL; + char *path = NULL; + unsigned char oldmac[6]; + + if (virAsprintf(&path, "%s/%s", + stateDir, + linkdev) < 0) { + virReportOOMError(); + return -1; + } + + if (virFileReadAll(path, VIR_MAC_STRING_BUFLEN, &macstr) < 0) { + return errno; + } + + if (virParseMacAddr(macstr, &oldmac[0]) != 0) { + macvtapError(VIR_ERR_INTERNAL_ERROR, + _("Cannot parse MAC address from '%s'"), + oldmacname); + return -1; + } + + /*reset mac and remove file-ignore results*/ + ignore_value(ifaceSetMacaddr(linkdev, oldmac)); + ignore_value(unlink(path)); + VIR_FREE(macstr); + return 0; +} /** * openMacvtapTap: @@ -575,7 +672,8 @@ openMacvtapTap(const char *tgifname, const unsigned char *vmuuid, virVirtualPortProfileParamsPtr virtPortProfile, char **res_ifname, - enum virVMOperationType vmOp) + enum virVMOperationType vmOp, + char *stateDir) { const char *type = "macvtap"; int c, rc; @@ -589,6 +687,19 @@ openMacvtapTap(const char *tgifname, VIR_DEBUG("%s: VM OPERATION: %s", __FUNCTION__, virVMOperationTypeToString(vmOp)); + /** Note: When using PASSTHROUGH mode with MACVTAP devices the link + * device's MAC address must be set to the VMs MAC address. In + * order to not confuse the first switch or bridge in line this MAC + * address must be reset when the VM is shut down. + * This is especially important when using SRIOV capable cards that + * emulate their switch in firmware. + */ + if (mode == VIR_DOMAIN_NETDEV_MACVTAP_MODE_PASSTHRU) { + if (replaceMacAdress(macaddress, linkdev, stateDir) != 0) { + return -1; + } + } + if (tgifname) { if(ifaceGetIndex(false, tgifname, &ifindex) == 0) { if (STRPREFIX(tgifname, @@ -684,8 +795,14 @@ void delMacvtap(const char *ifname, const unsigned char *macaddr, const char *linkdev, - virVirtualPortProfileParamsPtr virtPortProfile) + int mode, + virVirtualPortProfileParamsPtr virtPortProfile, + char *stateDir) { + if (mode == VIR_DOMAIN_NETDEV_MACVTAP_MODE_PASSTHRU) { + restoreMacAddress(linkdev, stateDir); + } + if (ifname) { vpDisassociatePortProfileId(ifname, macaddr, linkdev, diff --git a/src/util/macvtap.h b/src/util/macvtap.h index a1383c4545..2843596cd4 100644 --- a/src/util/macvtap.h +++ b/src/util/macvtap.h @@ -83,12 +83,15 @@ int openMacvtapTap(const char *ifname, const unsigned char *vmuuid, virVirtualPortProfileParamsPtr virtPortProfile, char **res_ifname, - enum virVMOperationType vmop); + enum virVMOperationType vmop, + char *stateDir); void delMacvtap(const char *ifname, const unsigned char *macaddress, const char *linkdev, - virVirtualPortProfileParamsPtr virtPortProfile); + int mode, + virVirtualPortProfileParamsPtr virtPortProfile, + char *stateDir); int vpAssociatePortProfileId(const char *macvtap_ifname, const unsigned char *macvtap_macaddr,