[libvirt] [PATCH 5/5] qemu: Implement usernet address
Michal Privoznik
mprivozn at redhat.com
Wed Sep 13 10:46:49 UTC 2017
On 09/12/2017 09:16 PM, Laine Stump wrote:
> On 09/12/2017 05:32 AM, Michal Privoznik wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1075520
>>
>> Apart from generic checks, we need to constrain netmask/prefix
>> lenght a bit. Thing is, with current implementation QEMU needs to
>> be able to 'assign' some IP addresses to the virtual network. For
>> instance, the default gateway is at x.x.x.2, dns is at x.x.x.3,
>> the default DHCP range is x.x.x.15-x.x.x.30. Since we don't
>> expose these settings yet, it's safer to require shorter prefix
>> to have room for the defaults.
>>
>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>> ---
>> src/qemu/qemu_command.c | 22 ++++++++++
>> src/qemu/qemu_domain.c | 49 ++++++++++++++++++++++
>> .../qemuxml2argv-net-user-addr.args | 25 +++++++++++
>> tests/qemuxml2argvtest.c | 1 +
>> 4 files changed, 97 insertions(+)
>> create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-net-user-addr.args
>>
>> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>> index d553df57f..3e1bc5fa8 100644
>> --- a/src/qemu/qemu_command.c
>> +++ b/src/qemu/qemu_command.c
>> @@ -3805,6 +3805,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
>> virDomainNetType netType = virDomainNetGetActualType(net);
>> virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
>> size_t i;
>> + char *addr = NULL;
>> char *ret = NULL;
>>
>> if (net->script && netType != VIR_DOMAIN_NET_TYPE_ETHERNET) {
>> @@ -3873,6 +3874,26 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
>> break;
>>
>> case VIR_DOMAIN_NET_TYPE_USER:
>> + virBufferAsprintf(&buf, "user%c", type_sep);
>> + for (i = 0; i < net->hostIP.nips; i++) {
>> + const virNetDevIPAddr *ip = net->hostIP.ips[i];
>> + const char *prefix = "";
>> +
>> + if (!(addr = virSocketAddrFormat(&ip->address)))
>> + goto cleanup;
>> +
>> + if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET))
>> + prefix = "net=";
>> + if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6))
>> + prefix = "ipv6-net";
>
>
> You're missing an "=" after ipv6-net.
>
>
>> +
>> + virBufferAsprintf(&buf, "%s%s", prefix, addr);
>> + if (ip->prefix)
>> + virBufferAsprintf(&buf, "/%u", ip->prefix);
>> + virBufferAddChar(&buf, ',');
>> + }
>> + break;
>> +
>> case VIR_DOMAIN_NET_TYPE_INTERNAL:
>> virBufferAsprintf(&buf, "user%c", type_sep);
>> break;
>> @@ -3928,6 +3949,7 @@ qemuBuildHostNetStr(virDomainNetDefPtr net,
>> cleanup:
>> virBufferFreeAndReset(&buf);
>> virObjectUnref(cfg);
>> + VIR_FREE(addr);
>
> You could have made addr local to the NET_TYPE_USER case, but then we
> would have to move it out if we added any additional error checking in
> the future (i.e. I agree with you putting it in the scope of the entire
> function)
>
>> return ret;
>> }
>>
>> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
>> index 72031893f..bf0c7300c 100644
>> --- a/src/qemu/qemu_domain.c
>> +++ b/src/qemu/qemu_domain.c
>> @@ -3338,9 +3338,11 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
>> void *opaque ATTRIBUTE_UNUSED)
>> {
>> int ret = -1;
>> + size_t i;
>>
>> if (dev->type == VIR_DOMAIN_DEVICE_NET) {
>> const virDomainNetDef *net = dev->data.net;
>> + bool hasIPv4 = false, hasIPv6 = false;
>>
>> if (net->guestIP.nroutes || net->guestIP.nips) {
>> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> @@ -3350,6 +3352,53 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
>> goto cleanup;
>> }
>>
>> + if (net->type == VIR_DOMAIN_NET_TYPE_USER) {
>> + if (net->hostIP.nroutes) {
>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> + _("Invalid attempt to set network interface "
>> + "guest-side IP address info, "
>> + "not supported by QEMU"));
>
> I agree with Martin that you should specifically say that you can't set
> <route>, not "IP address info". Of course this will need to change,
> since it's guestIP.nips that we want to allow.
>
>> + goto cleanup;
>> + }
>> +
>> + for (i = 0; i < net->hostIP.nips; i++) {
>> + const virNetDevIPAddr *ip = net->hostIP.ips[i];
>> +
>> + if (VIR_SOCKET_ADDR_VALID(&ip->peer)) {
>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> + _("peers are not supported by QEMU"));
>> + goto cleanup;
>
> Aside from the humor that Martin finds in this message, it's also not
> correct. It *is* allowed to set a peer IP on the host side of a
> *tap-based* network device with qemu. (and not allowed to set the peer
> IP on the guest side of *any* type of network device).
>
>> + }
>> +
>> + if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET)) {
>> + if (hasIPv4) {
>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> + _("Only one IPv4 address allowed"));
>> + goto cleanup;
>> + }
>> + hasIPv4 = true;
>
> Aha! You *are* checking for this! (maybe say "... per interface ...")
>
>
>> + }
>> +
>> + if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6)) {
>> + if (hasIPv6) {
>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> + _("Only one IPv6 address allowed"));
>> + goto cleanup;
>> + }
>> + hasIPv6 = true;
>> + }
>> +
>> + /* QEMU needs some space to have
>> + * some other 'hosts' on the network. */
>> + if ((hasIPv4 && ip->prefix > 27) ||
>> + (hasIPv6 && ip->prefix > 120)) {
>> + virReportError(VIR_ERR_XML_ERROR, "%s",
>> + _("prefix too long"));
>
> You should also probably check for conflict with the addresses that are
> automatically used by slirp for DNS, default route, dhcp server, etc.
> (Although I *hate* needing to hard code stuff like that :-/)
Do I? If the prefix allows sufficiently enough room for them then the
defaults shouldn't clash. Or you mean checking against host's IPs? The
defaults according to the qemu docs are as follows:
host = x.x.x.2
dhcpstart = x.x.x.15 - x.x.x.30
dns = x.x.x.3
smb = x.x.x.4
Michal
More information about the libvir-list
mailing list