From: Chen Hanxiao <chenhanxiao@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@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;
+
+    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;
+
+                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) {
+            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;
+    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

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On Mon, Jan 29, 2018 at 16:35:34 +0800, Chen Hanxiao wrote:
> From: Chen Hanxiao <chenhanxiao@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@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
> 
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