domifaddr: Implement the public APIs

Define helper function virDomainInterfaceFree, which allows
the upper layer application to free the domain interface object
conveniently.

The API is going to provide multiple methods by flags, e.g.
  * Query guest agent
  * Parse DHCP lease file

include/libvirt/libvirt-domain.h
  * Define virDomainInterfaceAddresses, virDomainInterfaceFree
  * Define structs virDomainInterface, virDomainIPAddress

src/driver-hypervisor.h:
  * Define domainInterfaceAddresses

src/libvirt-domain.c:
  * Implement virDomainInterfaceAddresses
  * Implement virDomainInterfaceFree

src/libvirt_public.syms:
  * Export the new symbols
Signed-off-by: NNehal J Wani <nehaljw.kkd1@gmail.com>

include/libvirt/libvirt-domain.h

@@ -3739,5 +3739,37 @@ typedef struct _virTypedParameter virMemoryParameter;
  */
 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 */
+
+# ifdef VIR_ENUM_SENTINELS
+    VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LAST
+# endif
+} virDomainInterfaceAddressesSource;
+
+typedef struct _virDomainInterfaceIPAddress virDomainIPAddress;
+typedef virDomainIPAddress *virDomainIPAddressPtr;
+struct _virDomainInterfaceIPAddress {
+    int type;                /* virIPAddrType */
+    char *addr;              /* IP address */
+    unsigned int prefix;     /* IP address prefix */
+};
+
+typedef struct _virDomainInterface virDomainInterface;
+typedef virDomainInterface *virDomainInterfacePtr;
+struct _virDomainInterface {
+    char *name;                     /* interface name */
+    char *hwaddr;                   /* hardware address */
+    unsigned int naddrs;            /* number of items in @addrs */
+    virDomainIPAddressPtr addrs;    /* array of IP addresses */
+};
+
+int virDomainInterfaceAddresses(virDomainPtr dom,
+                                virDomainInterfacePtr **ifaces,
+                                unsigned int source,
+                                unsigned int flags);
+
+void virDomainInterfaceFree(virDomainInterfacePtr iface);
 
 #endif /* __VIR_LIBVIRT_DOMAIN_H__ */

src/driver-hypervisor.h

@@ -1185,6 +1185,11 @@ typedef int
                         unsigned int cellCount,
                         unsigned int flags);
 
+typedef int
+(*virDrvDomainInterfaceAddresses)(virDomainPtr dom,
+                                  virDomainInterfacePtr **ifaces,
+                                  unsigned int source,
+                                  unsigned int flags);
 
 typedef struct _virHypervisorDriver virHypervisorDriver;
 typedef virHypervisorDriver *virHypervisorDriverPtr;
@@ -1412,6 +1417,7 @@ struct _virHypervisorDriver {
     virDrvConnectGetAllDomainStats connectGetAllDomainStats;
     virDrvNodeAllocPages nodeAllocPages;
     virDrvDomainGetFSInfo domainGetFSInfo;
+    virDrvDomainInterfaceAddresses domainInterfaceAddresses;
 };
 
 

src/libvirt-domain.c

@@ -11416,3 +11416,122 @@ virDomainFSInfoFree(virDomainFSInfoPtr info)
 
     VIR_FREE(info);
 }
+
+/**
+ * virDomainInterfaceAddresses:
+ * @dom: domain object
+ * @ifaces: pointer to an array of pointers pointing to interface objects
+ * @source: one of the virDomainInterfaceAddressesSource constants
+ * @flags: currently unused, pass zero
+ *
+ * Return a pointer to the allocated array of pointers to interfaces
+ * present in given domain along with their IP and MAC addresses. Note that
+ * single interface can have multiple or even 0 IP addresses.
+ *
+ * This API dynamically allocates the virDomainInterfacePtr struct based on
+ * how many interfaces domain @dom has, usually there's 1:1 correlation. The
+ * count of the interfaces is returned as the return value.
+ *
+ * If @source is VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE, the DHCP lease
+ * file associated with any virtual networks will be examined to obtain
+ * the interface addresses. This only returns data for interfaces which
+ * are connected to virtual networks managed by libvirt.
+ *
+ * If @source is VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT, a configured
+ * guest agent is needed for successful return from this API. Moreover, if
+ * guest agent is used then the interface name is the one seen by guest OS.
+ * To match such interface with the one from @dom XML use MAC address or IP
+ * range.
+ *
+ * @ifaces->name and @ifaces->hwaddr are never NULL.
+ *
+ * The caller *must* free @ifaces when no longer needed. Usual use case
+ * looks like this:
+ *
+ *  virDomainInterfacePtr *ifaces = NULL;
+ *  int ifaces_count = 0;
+ *  size_t i, j;
+ *  virDomainPtr dom = ... obtain a domain here ...;
+ *
+ *  if ((ifaces_count = virDomainInterfaceAddresses(dom, &ifaces,
+ *           VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE)) < 0)
+ *      goto cleanup;
+ *
+ *  ... do something with returned values, for example:
+ *  for (i = 0; i < ifaces_count; i++) {
+ *      printf("name: %s", ifaces[i]->name);
+ *      printf(" hwaddr: %s", ifaces[i]->hwaddr);
+ *
+ *      for (j = 0; j < ifaces[i]->naddrs; j++) {
+ *          virDomainIPAddressPtr ip_addr = ifaces[i]->addrs + j;
+ *          printf("[addr: %s prefix: %d type: %d]",
+ *                 ip_addr->addr, ip_addr->prefix, ip_addr->type);
+ *      }
+ *      printf("\n");
+ *  }
+ *
+ *  cleanup:
+ *      if (ifaces && ifaces_count > 0)
+ *          for (i = 0; i < ifaces_count; i++)
+ *              virDomainInterfaceFree(ifaces[i]);
+ *      free(ifaces);
+ *
+ * Returns the number of interfaces on success, -1 in case of error.
+ */
+int
+virDomainInterfaceAddresses(virDomainPtr dom,
+                            virDomainInterfacePtr **ifaces,
+                            unsigned int source,
+                            unsigned int flags)
+{
+    VIR_DOMAIN_DEBUG(dom, "ifaces=%p, source=%d, flags=%x", ifaces, source, flags);
+
+    virResetLastError();
+
+    if (ifaces)
+        *ifaces = NULL;
+    virCheckDomainReturn(dom, -1);
+    virCheckNonNullArgGoto(ifaces, error);
+    virCheckReadOnlyGoto(dom->conn->flags, error);
+
+    if (dom->conn->driver->domainInterfaceAddresses) {
+        int ret;
+        ret = dom->conn->driver->domainInterfaceAddresses(dom, ifaces, source, flags);
+        if (ret < 0)
+            goto error;
+        return ret;
+    }
+
+    virReportError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
+
+ error:
+    virDispatchError(dom->conn);
+    return -1;
+}
+
+
+/**
+ * virDomainInterfaceFree:
+ * @iface: an interface object
+ *
+ * Free the interface object. The data structure is
+ * freed and should not be used thereafter. If @iface
+ * is NULL, then this method has no effect.
+ */
+void
+virDomainInterfaceFree(virDomainInterfacePtr iface)
+{
+    size_t i;
+
+    if (!iface)
+        return;
+
+    VIR_FREE(iface->name);
+    VIR_FREE(iface->hwaddr);
+
+    for (i = 0; i < iface->naddrs; i++)
+        VIR_FREE(iface->addrs[i].addr);
+    VIR_FREE(iface->addrs);
+
+    VIR_FREE(iface);
+}

src/libvirt_public.syms

@@ -700,6 +700,8 @@ LIBVIRT_1.2.14 {
         virDomainIOThreadsInfoFree;
         virDomainGetIOThreadsInfo;
         virDomainPinIOThread;
+        virDomainInterfaceAddresses;
+        virDomainInterfaceFree;
 } LIBVIRT_1.2.12;
 
 # .... define new API here using predicted next version number ....