Re: [libvirt] [PATCHv7 3/4] domifaddr: Implement the API for qemu

By querying the qemu guest agent with the QMP command "guest-network-get-interfaces" and converting the received JSON output to structured objects. Although "ifconfig" is deprecated, IP aliases created by "ifconfig" are supported by this API. The legacy syntax of an IP alias is: "<ifname>:<alias-name>". Since we want all aliases to be clubbed under parent interface, simply stripping ":<alias-name>" suffices. Note that IP aliases formed by "ip" aren't visible to "ifconfig", and aliases created by "ip" do not have any specific name. But we are lucky, as qemu guest agent detects aliases created by both.

+static int +qemuGetDHCPInterfaces(virDomainPtr dom, + virDomainObjPtr vm, + virDomainInterfacePtr **ifaces) +{ + int rv = -1; + int n_leases = 0; + size_t i, j; + size_t ifaces_count = 0; + virNetworkPtr network; + char macaddr[VIR_MAC_STRING_BUFLEN]; + virDomainInterfacePtr iface = NULL; + virNetworkDHCPLeasePtr *leases = NULL; + virDomainInterfacePtr *ifaces_ret = NULL; + + for (i = 0; i < vm->def->nnets; i++) { + virMacAddrFormat(&(vm->def->nets[i]->mac), macaddr); + network = virNetworkLookupByName(dom->conn, + vm->def->nets[i]->data.network.name); + + if (dom->conn->networkDriver && + dom->conn->networkDriver->networkGetDHCPLeases) {

+ n_leases = virNetworkGetDHCPLeases(network, macaddr, + &leases, 0);

+ if (n_leases < 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; + } + } + + *ifaces = ifaces_ret; + ifaces_ret = NULL; + rv = ifaces_count; + + cleanup: + 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; +}