[libvirt] [PATCHv2 02/13] New virNetworkDef utility functions
Later patches will add the possibility to define a network's netmask
as a prefix (0-32, or 0-128 in the case of IPv6). To make it easier to
deal with definition of both kinds (prefix or netmask), add two new
functions:
virNetworkDefNetmask: return a copy of the netmask into a
virSocketAddr. If no netmask was specified in the XML, create a
default netmask based on the network class of the virNetworkDef's IP
address.
virNetworkDefPrefix: return the netmask as numeric prefix (or the
default prefix for the network class of the virNetworkDef's IP
address, if no netmask was specified in the XML)
---
V2 Changes:
* expose the nitty-gritty of detecting class A-C networks, rather
than using IN_CLASSx() macros (which aren't guaranteed to be on
all platforms)
src/conf/network_conf.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
src/conf/network_conf.h | 3 +++
src/libvirt_private.syms | 2 ++
3 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index b469269..427b338 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -207,6 +207,52 @@ void virNetworkRemoveInactive(virNetworkObjListPtr nets,
}
}
+/* return number of 1 bits in netmask for the network's ipAddress,
+ * or -1 on error
+ */
+int virNetworkDefPrefix(const virNetworkDefPtr def)
+{
+ if (VIR_SOCKET_HAS_ADDR(&def->netmask)) {
+ return virSocketGetNumNetmaskBits(&def->netmask);
+ } else if (VIR_SOCKET_IS_FAMILY(&def->ipAddress, AF_INET)) {
+ /* Return the natural prefix for the network's ip address.
+ * On Linux we could use the IN_CLASSx() macros, but those
+ * aren't guaranteed on all platforms, so we just deal with
+ * the bits ourselves.
+ */
+ const unsigned char *octets
+ = (const unsigned char
*)(&def->ipAddress.data.inet4.sin_addr.s_addr);
+ if ((octets[0] & 0x80) == 0) {
+ /* Class A network */
+ return 8;
+ } else if ((octets[0] & 0xC0) == 0x80) {
+ /* Class B network */
+ return 16;
+ } else if ((octets[0] & 0xE0) == 0xC0) {
+ /* Class C network */
+ return 24;
+ }
+ return -1;
+ }
+ return -1;
+}
+
+/* Fill in a virSocketAddr with the proper netmask for this
+ * definition, based on either the definition's netmask, or its
+ * prefix. Return -1 on error (and set the netmask family to AF_UNSPEC)
+ */
+int virNetworkDefNetmask(const virNetworkDefPtr def,
+ virSocketAddrPtr netmask)
+{
+ if (VIR_SOCKET_IS_FAMILY(&def->netmask, AF_INET)) {
+ *netmask = def->netmask;
+ return 0;
+ }
+
+ return virSocketAddrPrefixToNetmask(virNetworkDefPrefix(def), netmask,
+ VIR_SOCKET_FAMILY(&def->ipAddress));
+}
+
static int
virNetworkDHCPRangeDefParseXML(virNetworkDefPtr def,
diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h
index 7d31693..a922d28 100644
--- a/src/conf/network_conf.h
+++ b/src/conf/network_conf.h
@@ -133,6 +133,9 @@ virNetworkDefPtr virNetworkDefParseNode(xmlDocPtr xml,
char *virNetworkDefFormat(const virNetworkDefPtr def);
+int virNetworkDefPrefix(const virNetworkDefPtr def);
+int virNetworkDefNetmask(const virNetworkDefPtr def,
+ virSocketAddrPtr netmask);
int virNetworkSaveXML(const char *configDir,
virNetworkDefPtr def,
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 19841ef..d9ba7b1 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -578,9 +578,11 @@ virNetworkAssignDef;
virNetworkConfigFile;
virNetworkDefFormat;
virNetworkDefFree;
+virNetworkDefNetmask;
virNetworkDefParseFile;
virNetworkDefParseNode;
virNetworkDefParseString;
+virNetworkDefPrefix;
virNetworkDeleteConfig;
virNetworkFindByName;
virNetworkFindByUUID;
--
1.7.3.4