Re: [libvirt] [PATCH] network: disallow <bandwidth>/<mac> for bridged/macvtap networks

On 30.01.2014 11:26, Laine Stump wrote: > On 01/27/2014 06:08 PM, Michal Privoznik wrote: >> On 24.01.2014 13:18, Laine Stump wrote: >>> https://bugzilla.redhat.com/show_bug.cgi?id=1057321 pointed out that >>> we weren't honoring the <bandwidth> element in libvirt networks using >>> <forward mode='bridge'/>. In fact, these networks are just a method of >>> giving a libvirt network name to an existing Linux host bridge on the >>> system, and even if it were technically possible for us to set >>> network-wide bandwidth limits for all the taps on a bridge, it's >>> probably not a polite thing to do since libvirt is just using a bridge >>> that was created by someone else for other purposes. So the proper >>> thing is to just log an error when someone tries to put a <bandwidth> >>> element in that type of network. >>> >>> While looking through the network XML documentation and comparing it >>> to the networkValidate function, I noticed that we also ignore the >>> presence of a mac address in the config, even though we do nothing >>> with it in this case either. >>> >>> This patch updates networkValidate() (which is called any time a >>> persistent network is defined, or a transient network created) to log >>> an error and fail if it finds either a <bandwidth> or <mac> element >>> and the network forward mode is anything except 'route'. 'nat', or >>> nothing. (Yes, neither of those elements is acceptable for any macvtap >>> mode, nor for a hostdev network). >>> >>> NB: This does *not* cause failure to start any existing network that >>> contains one of those elements, so someone might have erroneously >>> defined such a network in the past, and that network will continue to >>> function unmodified. I considered it too disruptive to suddenly break >>> working configs on the next reboot after a libvirt upgrade. >>> --- >>> src/network/bridge_driver.c | 19 ++++++++++++++++++- >>> 1 file changed, 18 insertions(+), 1 deletion(-) >>> >>> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c >>> index 0b43a67..3b9b58d 100644 >>> --- a/src/network/bridge_driver.c >>> +++ b/src/network/bridge_driver.c >>> @@ -2407,8 +2407,17 @@ networkValidate(virNetworkDriverStatePtr >>> driver, >>> virNetworkSetBridgeMacAddr(def); >>> } else { >>> /* They are also the only types that currently support >>> setting >>> - * an IP address for the host-side device (bridge) >>> + * a MAC or IP address for the host-side device (bridge), DNS >>> + * configuration, or network-wide bandwidth limits. >>> */ >>> + if (def->mac_specified) { >>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, >>> + _("Unsupported <mac> element in network >>> %s " >>> + "with forward mode='%s'"), >>> + def->name, >>> + >>> virNetworkForwardTypeToString(def->forward.type)); >>> + return -1; >>> + } >>> if (virNetworkDefGetIpByIndex(def, AF_UNSPEC, 0)) { >>> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, >>> _("Unsupported <ip> element in >>> network %s " >>> @@ -2433,6 +2442,14 @@ networkValidate(virNetworkDriverStatePtr >>> driver, >>> >>> virNetworkForwardTypeToString(def->forward.type)); >>> return -1; >>> } >>> + if (def->bandwidth) { >>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, >>> + _("Unsupported network-wide <bandwidth> >>> element " >>> + "in network %s with forward mode='%s'"), >>> + def->name, >>> + >>> virNetworkForwardTypeToString(def->forward.type)); >>> + return -1; >>> + } >>> } >>> >>> /* We only support dhcp on one IPv4 address and >>> >> >> I think think this is exactly the opposite of what I've just pushed :) > > Indeed :-) I really should get myself Cc'ed on more bugzilla > copmonents/products so that I notice these things sooner. > >> I mean: >> >> commit 2996e6be19a13199ded7c2aa21039cca97318e01 >> Author: Michal Privoznik <mprivozn(a)redhat.com&gt; >> AuthorDate: Wed Jan 22 18:58:33 2014 +0100 >> Commit: Michal Privoznik <mprivozn(a)redhat.com&gt; >> CommitDate: Mon Jan 27 12:11:27 2014 +0100 >> >> networkAllocateActualDevice: Set QoS for bridgeless networks too >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1055484 >> >> >> >> In the commit I'm trying to inherit network QoS to the interface that >> is just being created. Yes, it involves some magic but it works. I >> guess we need to agree if we want this approach or mine as they seem >> to be contradictionary. > > Since you've reverted yours, should I push this? > > After that, we may want to talk about 1) supporting use of the "dev" > attribute in <forward> to name a *single* forwarding interface, and > applying a network's <bandwidth> to that interface (while still failing > in other cases), and 2) maybe supporting Open vSwitch in a more thorough > manner so that projects like ovirt can use it to create intermediate > bridges and manage their bandwidth via libvirt <network> xml. > Yes. Please do push your patch. ACK.