[libvirt] [PATCH v3 2/4] qemu: introduce qemuARPGetInterfaces to get IP from host's arp table
Peter Krempa
pkrempa at redhat.com
Mon Jan 29 12:31:49 UTC 2018
On Mon, Jan 29, 2018 at 16:35:34 +0800, Chen Hanxiao wrote:
> From: Chen Hanxiao <chenhanxiao at gmail.com>
>
> introduce VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP to get ip address
> of VM from the output of /proc/net/arp
>
> Signed-off-by: Chen Hanxiao <chenhanxiao at gmail.com>
> ---
> v3:
> add docs in virDomainInterfaceAddresses
> remove error label
> show network interface which did not match the arp table
>
> include/libvirt/libvirt-domain.h | 1 +
> src/libvirt-domain.c | 7 +++
> src/qemu/qemu_driver.c | 96 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 104 insertions(+)
>
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index 4048acf38..38e2d9a3e 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -4665,6 +4665,7 @@ typedef virMemoryParameter *virMemoryParameterPtr;
> typedef enum {
> VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE = 0, /* Parse DHCP lease file */
> VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT = 1, /* Query qemu guest agent */
> + VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP = 2, /* Query ARP tables */
>
> # ifdef VIR_ENUM_SENTINELS
> VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LAST
> diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> index eaec0979a..1ae83610d 100644
> --- a/src/libvirt-domain.c
> +++ b/src/libvirt-domain.c
> @@ -11721,6 +11721,13 @@ virDomainFSInfoFree(virDomainFSInfoPtr info)
> * To match such interface with the one from @dom XML use MAC address or IP
> * range.
> *
> + * If @source is VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP, the /proc/net/arp
> + * will be check to obtain the interface addresses.
> + * As the arp cache did not refresh in time, the returned ip address
> + * may be unreachable.
> + * As the route config of the guest, the returned mac address
> + * may be duplicated.
> + *
> * @ifaces->name and @ifaces->hwaddr are never NULL.
> *
> * The caller *must* free @ifaces when no longer needed. Usual use case
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index a203c9297..d0cb88053 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -70,6 +70,7 @@
> #include "virnetdevopenvswitch.h"
> #include "capabilities.h"
> #include "viralloc.h"
> +#include "virarptable.h"
> #include "viruuid.h"
> #include "domain_conf.h"
> #include "domain_audit.h"
> @@ -160,6 +161,9 @@ static int qemuGetDHCPInterfaces(virDomainPtr dom,
> virDomainObjPtr vm,
> virDomainInterfacePtr **ifaces);
>
> +static int qemuARPGetInterfaces(virDomainObjPtr vm,
> + virDomainInterfacePtr **ifaces);
> +
> static virQEMUDriverPtr qemu_driver;
>
>
> @@ -20384,6 +20388,10 @@ qemuDomainInterfaceAddresses(virDomainPtr dom,
>
> break;
>
> + case VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP:
> + ret = qemuARPGetInterfaces(vm, ifaces);
> + break;
> +
> default:
> virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED,
> _("Unknown IP address data source %d"),
> @@ -20494,6 +20502,94 @@ qemuGetDHCPInterfaces(virDomainPtr dom,
> }
>
>
> +static int
> +qemuARPGetInterfaces(virDomainObjPtr vm,
> + virDomainInterfacePtr **ifaces)
> +{
> + size_t i, j;
> + size_t ifaces_count = 0;
> + int ret = -1;
> + char macaddr[VIR_MAC_STRING_BUFLEN];
> + virDomainInterfacePtr *ifaces_ret = NULL;
> + virDomainInterfacePtr iface = NULL;
> + virArpTablePtr table;
> + int got_one = 0;
Isn't this a bool in fact?
> +
> + table = virArpTableGet();
> + if (!table)
> + goto cleanup;
> +
> + for (i = 0; i < vm->def->nnets; i++) {
> + got_one = 0;
> + if (vm->def->nets[i]->type != VIR_DOMAIN_NET_TYPE_NETWORK)
> + continue;
> +
> + virMacAddrFormat(&(vm->def->nets[i]->mac), macaddr);
> + virArpTableEntry entry;
> + for (j = 0; j < table->n; j++) {
> + entry = table->t[j];
> + if (STREQ(entry.mac, macaddr)) {
> + got_one = 1;
> + if (VIR_EXPAND_N(ifaces_ret, ifaces_count, 1) < 0)
> + goto cleanup;
> + if (VIR_ALLOC(ifaces_ret[ifaces_count - 1]) < 0)
> + goto cleanup;
> +
VIR_APPEND_ELEMENT
Looks like you inspired youself in qemuAgentGetInterfaces which isn't
probably the right place for nice code.
> + iface = ifaces_ret[ifaces_count - 1];
> + iface->naddrs = 1;
> + if (VIR_ALLOC_N(iface->addrs, iface->naddrs) < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->name, vm->def->nets[i]->ifname) < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->hwaddr, macaddr) < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->addrs->addr, entry.ipaddr) < 0)
> + goto cleanup;
> + }
> + }
> +
> + if (got_one == 0) {
Why do you add a dummy entry if given interface does not have one? No
other gathering method does this.
> + if (VIR_EXPAND_N(ifaces_ret, ifaces_count, 1) < 0)
> + goto cleanup;
> + if (VIR_ALLOC(ifaces_ret[ifaces_count - 1]) < 0)
> + goto cleanup;
> +
> + iface = ifaces_ret[ifaces_count - 1];
> + iface->naddrs = 1;
> + if (VIR_ALLOC_N(iface->addrs, iface->naddrs) < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->name, "") < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->hwaddr, macaddr) < 0)
> + goto cleanup;
> +
> + if (VIR_STRDUP(iface->addrs->addr, "") < 0)
> + goto cleanup;
> + }
> + }
> +
> + *ifaces = ifaces_ret;
> + ifaces_ret = NULL;
VIR_STEAL_PTR
> + ret = ifaces_count;
> +
> + cleanup:
> + virArpTableFree(table);
> +
> + if (ifaces_ret) {
> + for (i = 0; i < ifaces_count; i++)
> + virDomainInterfaceFree(ifaces_ret[i]);
> + }
> + VIR_FREE(ifaces_ret);
> +
> + return ret;
> +}
> +
> +
> static int
> qemuDomainSetUserPassword(virDomainPtr dom,
> const char *user,
> --
> 2.14.3
>
> --
> libvir-list mailing list
> libvir-list at redhat.com
> https://www.redhat.com/mailman/listinfo/libvir-list
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