[libvirt] [PATCH] libxl: add .domainInterfaceAddresses
Jim Fehlig
jfehlig at suse.com
Wed May 25 03:42:36 UTC 2016
On 05/22/2016 09:34 PM, Chun Yan Liu wrote:
>
>>>> On 5/17/2016 at 11:46 PM, in message
> <2fa0cb6f-ea83-d6f3-18f8-51a671574205 at laine.org>, Laine Stump <laine at laine.org>
> wrote:
>> On 05/16/2016 06:05 PM, Jim Fehlig wrote:
>>> Chun Yan Liu wrote:
>>>>>>> On 5/14/2016 at 07:47 AM, in message <5736677D.8030209 at suse.com>, Jim Fehlig
>>>> <jfehlig at suse.com> wrote:
>>>>> On 05/13/2016 12:21 AM, Chunyan Liu wrote:
>>>>>> Add .domainInterfaceAddresses so that user can have a way to
>>>>>> get domain interface address by 'virsh domifaddr'. Currently
>>>>>> it only supports '--source lease'.
>>>>>>
>>>>>> Signed-off: Chunyan Liu <cyliu at suse.com>
>>>>>> ---
>>>>>> src/libxl/libxl_driver.c | 140
>>>>> +++++++++++++++++++++++++++++++++++++++++++++++
>>>>>> 1 file changed, 140 insertions(+)
>>>>>>
>>>>>> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
>>>>>> index 062d6f8..f2bd6fa 100644
>>>>>> --- a/src/libxl/libxl_driver.c
>>>>>> +++ b/src/libxl/libxl_driver.c
>>>>>> @@ -5425,6 +5425,145 @@ static int libxlNodeGetSecurityModel(virConnectPtr
>>>>> conn,
>>>>>> return 0;
>>>>>> }
>>>>>>
>>>>>> +static int
>>>>>> +libxlGetDHCPInterfaces(virDomainPtr dom,
>>>>>> + virDomainObjPtr vm,
>>>>>> + virDomainInterfacePtr **ifaces)
>>>>>> +{
>>>>>> + int rv = -1;
>>>>>> + int n_leases = 0;
>>>>>> + size_t i, j;
>>>>>> + size_t ifaces_count = 0;
>>>>>> + virNetworkPtr network = NULL;
>>>>>> + char macaddr[VIR_MAC_STRING_BUFLEN];
>>>>>> + virDomainInterfacePtr iface = NULL;
>>>>>> + virNetworkDHCPLeasePtr *leases = NULL;
>>>>>> + virDomainInterfacePtr *ifaces_ret = NULL;
>>>>>> +
>>>>>> + if (!dom->conn->networkDriver ||
>>>>>> + !dom->conn->networkDriver->networkGetDHCPLeases) {
>>>>>> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>>>>>> + _("Network driver does not support DHCP lease
>>>>> query"));
>>>>>> + return -1;
>>>>>> + }
>>>>>> +
>>>>>> + for (i = 0; i < vm->def->nnets; i++) {
>>>>>> + if (vm->def->nets[i]->type != VIR_DOMAIN_NET_TYPE_NETWORK)
>>>>>> + continue;
>>>>>> +
>>>>>> + virMacAddrFormat(&(vm->def->nets[i]->mac), macaddr);
>>>>>> + virObjectUnref(network);
>>>>>> + network = virNetworkLookupByName(dom->conn,
>>>>>> +
>> vm->def->nets[i]->data.network.name);
>>>>>> +
>>>>>> + if ((n_leases = virNetworkGetDHCPLeases(network, macaddr,
>>>>>> + &leases, 0)) < 0)
>>>>>> + goto error;
>>>>>> +
>>>>>> + if (n_leases) {
>>>>>> + if (VIR_EXPAND_N(ifaces_ret, ifaces_count, 1) < 0)
>>>>>> + goto error;
>>>>>> +
>>>>>> + if (VIR_ALLOC(ifaces_ret[ifaces_count - 1]) < 0)
>>>>>> + goto error;
>>>>>> +
>>>>>> + iface = ifaces_ret[ifaces_count - 1];
>>>>>> + /* Assuming each lease corresponds to a separate IP */
>>>>>> + iface->naddrs = n_leases;
>>>>>> +
>>>>>> + if (VIR_ALLOC_N(iface->addrs, iface->naddrs) < 0)
>>>>>> + goto error;
>>>>>> +
>>>>>> + if (VIR_STRDUP(iface->name, vm->def->nets[i]->ifname) < 0)
>>>>>> + goto cleanup;
>>>>>> +
>>>>>> + if (VIR_STRDUP(iface->hwaddr, macaddr) < 0)
>>>>>> + goto cleanup;
>>>>>> + }
>>>>>> +
>>>>>> + for (j = 0; j < n_leases; j++) {
>>>>>> + virNetworkDHCPLeasePtr lease = leases[j];
>>>>>> + virDomainIPAddressPtr ip_addr = &iface->addrs[j];
>>>>>> +
>>>>>> + if (VIR_STRDUP(ip_addr->addr, lease->ipaddr) < 0)
>>>>>> + goto cleanup;
>>>>>> +
>>>>>> + ip_addr->type = lease->type;
>>>>>> + ip_addr->prefix = lease->prefix;
>>>>>> + }
>>>>>> +
>>>>>> + for (j = 0; j < n_leases; j++)
>>>>>> + virNetworkDHCPLeaseFree(leases[j]);
>>>>>> +
>>>>>> + VIR_FREE(leases);
>>>>>> + }
>>>>>> +
>>>>>> + *ifaces = ifaces_ret;
>>>>>> + ifaces_ret = NULL;
>>>>>> + rv = ifaces_count;
>>>>>> +
>>>>>> + cleanup:
>>>>>> + virObjectUnref(network);
>>>>>> + if (leases) {
>>>>>> + for (i = 0; i < n_leases; i++)
>>>>>> + virNetworkDHCPLeaseFree(leases[i]);
>>>>>> + }
>>>>>> + VIR_FREE(leases);
>>>>>> +
>>>>>> + return rv;
>>>>>> +
>>>>>> + error:
>>>>>> + if (ifaces_ret) {
>>>>>> + for (i = 0; i < ifaces_count; i++)
>>>>>> + virDomainInterfaceFree(ifaces_ret[i]);
>>>>>> + }
>>>>>> + VIR_FREE(ifaces_ret);
>>>>>> +
>>>>>> + goto cleanup;
>>>>>> +}
>>>>>
>>>>> It's unfortunate this is a copy-paste from the qemu driver. The code is not
>>>>> trivial and any bug fixes in one copy could be missed in the other. A lot
>> of
>>>>> the
>>>>> function is domain related, so probably can't be abstracted further to the
>>>>> network code. Have you considered approaches that allow the drivers to
>> share
>>>>> this code?
>>>> Well, it can be extracted and placed in bridge_driver.c as
>> networkGetDHCPInterfaces,
>>>> but I don't know if that is acceptable?
>>> Hmm, maybe something like networkGetDHCPLeasesAll() is a better name.
>> Regardless
>>> of the name, I see that other functions in bridge_driver.c take a
>>> virDomainDefPtr, so maybe extracting the code to bridge_driver.c is
>> acceptable.
>>
>> Well, I don't really *like* the way that those network*() functions are
>> implemented (just by exporting a symbol, implying that any hypervisor
>> driver that uses them must directly link the bridge driver in, rather
>> than being able to load an alternative), but that was the most expedient
>> way of handling the need at the time, and nobody complained about it,
>> so... :-)
>>
>> Definitely duplication of code is bad (I say that although I do it a lot
>> myself!). And if a function is all about "doing something with a network
>> device / connection" and it will need access to the network object, I
>> think the network driver is the place to have it. *AND* if it's
>> something that's not needed directly in the public API, then making it
>> available as a public API call is a bad idea (since you're then stuck
>> with it forever).
>>
>> However, I don't know that I like the idea of a function in the network
>> driver that is trawling through the virDomainDef object. It may seem
>> like a fine distinction - returning the lease info for a single
>> interface vs. returning the lease info for all interfaces in the domain,
>> but it does take the co-mingling between the network and hypervisor
>> drivers to a new level. Yes, it's true that there are already functions
>> that are part of this "backend super double secret network API" (watch
>> Animal House and you'll understand the reference) that take a
>> virDomainDefPtr as an argument; but they only use it to format the
>> domain XML and send it to the network hook script. Technically there's
>> nothing preventing a function in the network driver from accessing every
>> attribute of the domain, or even modifying it :-O, that doesn't mean we
>> should do it though.
>>
>> I'm trying to completely recall a vague memory of something similar to
>> this that happened in the past - something that was needed in multiple
>> hypervisors (which would imply that it should live either in util or
>> conf), but that also needed to call a network function (or maybe some
>> other driver, I forget). When trying to maintain some sort of separation
>> and rules of engagement between the various components, there tend to be
>> cases that just don't fit within the mold.
>>
>> In this case, I'm wondering if maybe the duplication can be reduced by
>> creating a function in conf (either domain_conf.c or one of its
>> subsidiaries) that takes a *function as an argument and calls that
>> function for each interface. Something like this:
>>
>> int
>> virDomainGetDHCPInterfaces(virDomainDefPtr def,
>> virDomainDefGetDHCPLeasesCB getLeases,
>> virDomainInterfacePtr **ifaces)
>> {
>>
>> for (i = 0; i < def->nnets; i++) {
>> virDomainNetDefPtr net = def->nets[i];
>>
>> if (virDomainNetDefGetActualType(net) !=
>> VIR_DOMAIN_NET_TYPE_NETWORK)
>> continue;
>> if ((n_leases = getLeases(net->data.network.name, net->mac,
>> &leases)) < 0) {
>> OH NOES!!!!!
>> goto error;
>> if (n_leases) {
>> bobloblawlawblog.com ....
>> }
>>
>> etc etc.
>> }
>>
>> various cleanup stuff etc.
>>
>> }
>>
>> The function getLeases would be a thin (if any) wrapper around a
>> function in the network driver called networkGetDHCPLeases(). The
>> toplevel function in qemu and libxl would then be simple a bit of glue
>> followed by a call to virDomainGetDHCPInterfaces() with a pointer to the
>> appropriate getLeases function.
>>
>> This way we would eliminate almost all of the duplicate code (most would
>> go into domain_conf.c, and a bit into bridge_driver.c) without needing
>> to teach the network driver about the internal workings of a domain def.
>>
>> Does that make any sense?
> Had a look at this and tried, seems hard to put into domain_conf.c:
> except for the vm->def->nets, almost all the other things are called
> from src/libvirt-domain.c or src/libvirt-network.c, not only the
> getLeases cb of a specific network, but even the virDomainInterfacePtr
> itself is defined in libvirt-domain.h and also its Free function (in case of
> error, virNetworkDHCPLeaseFree and virDomainInterfaceFree are also
> needed). Ideas?
Hrm, maybe just go with the small amount of copied code? :-)
When originally looking at the patch, I thought it might be quite disruptive to
factor it out into something that could be used by both drivers. Unless others
have a clever idea, I'm leaning towards pushing this patch as is.
Regards,
Jim
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