2 p.m.
On 09/15/2013 11:49 PM, Nehal J Wani wrote:
By querying the driver for the path of the leases file for the given
virtual
network and parsing it to retrieve info.
src/network/bridge_driver.c:
* Implement networkGetDHCPLeases
* Implement networkGetDHCPLeasesForMAC
* Implement networkGetDHCPLeasesHelper
---
src/network/bridge_driver.c | 177 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 177 insertions(+)
}
+/* This function parese the leases file of dnsmasq.
s/parese/parses/
+ *
+ * An example of leases file content:
+ *
+ * 1379024255 52:54:00:20:70:3d 192.168.105.240 * *
+ * 1379023351 52:54:00:b1:70:19 192.168.105.201 * *
+ */
+static int
+networkGetDHCPLeasesHelper(virNetworkPtr network,
+ virNetworkObjPtr obj,
+ const char *mac,
+ virNetworkDHCPLeasesPtr **leases)
+{
+ int rv = -1;
+ size_t i = 0;
+ size_t nleases = 0;
+ char *leasefile;
+ char **lease_fields;
+ char dhcpentry[VIR_NETWORK_DHCP_LEASE_LENGTH_MAX];
+ virNetworkDHCPLeasesPtr *leases_ret = NULL;
+ FILE *fp = NULL;
+
+ if (!network) {
+ virReportError(VIR_ERR_NO_NETWORK, "%s",
+ _("no network with matching name"));
+ return -1;
+ }
Dead code (network is always non-NULL if you get here).
+
+ /* Retrieve leases file location */
+ leasefile = networkDnsmasqLeaseFileNameDefault(network->name);
+ if (!(fp = fopen(leasefile, "r"))) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Unable to open leases file: %s"), leasefile);
+ goto cleanup;
+ }
+
+ while (fgets(dhcpentry, sizeof(dhcpentry), fp) != NULL) {
Rather than hand-rolling your file reading, I would suggest using
virFileReadAll(leasefile, len, &buf), and then loop over the returned
buffer. That gives you nicer guarantees about handling things like
interrupts that fgets() might get confused on.
+ virNetworkDHCPLeasesPtr lease = NULL;
+
+ /* Remove newline */
+ dhcpentry[strlen(dhcpentry) - 1] = '\0';
+
+ /* Split the lease line */
+ lease_fields = virStringSplit(dhcpentry, " ",
VIR_NETWORK_DHCP_LEASE_FIELDS);
+
+ if (virStringListLength(lease_fields) != VIR_NETWORK_DHCP_LEASE_FIELDS) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Number of lease params aren't equal to:
%d"),
+ VIR_NETWORK_DHCP_LEASE_FIELDS);
+ goto error;
+ }
+
+ if (mac && STRNEQ(mac, lease_fields[1]))
This may not do what you want - remember, 'mac' is specified by the
user, whereas lease_fields[1] is specified by dnsmasq. While we can
reasonably assume that dnsmasq always uses a canonical MAC
representation (such as 52:54:00:1a:0a:6d), the user may have passed in
a non-canonical form that we can still parse and recognize as the same
address (such as 52:54:00:1A:0a:6D, or even 52:54:0:1a:a:6d). You want
to use virMacAddrCompare() instead of STRNEQ.
+ continue;
Memleak. lease_fields is allocated each iteration of the loop, so it
must be freed each iteration of the loop.
+
+ if (VIR_EXPAND_N(leases_ret, nleases, 1) < 0)
+ goto error;
+
+ if (VIR_ALLOC(leases_ret[nleases - 1]) < 0)
+ goto error;
Rather than trying to allocate it into the destination array, it might
be better to allocate into a local variable, and only on successful
population of the entire element, use VIR_INSERT_ELEMENT to move it into
the array at that time.
+
+ lease = leases_ret[nleases - 1];
+
+ /* Convert expirytime here */
+ if (virStrToLong_ll(lease_fields[0], NULL, 10, &(lease->expirytime)) <
0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Unable to convert lease expiry time to integer:
%s"),
+ lease_fields[0]);
+ goto error;
+ }
+
+ /* Hardcoded, as dnsmasq uses ipv4 */
+ lease->type = VIR_IP_ADDR_TYPE_IPV4;
+ lease->prefix =
virSocketAddrGetIpPrefix(&obj->def->ips->address,
+ &obj->def->ips->netmask,
+ obj->def->ips->prefix);
+
+ if ((VIR_STRDUP(lease->mac, lease_fields[1]) < 0) ||
+ (VIR_STRDUP(lease->ipaddr, lease_fields[2]) < 0) ||
+ (VIR_STRDUP(lease->hostname, lease_fields[3]) < 0) ||
+ (VIR_STRDUP(lease->clientid, lease_fields[4]) < 0))
+ goto error;
+ }
Transfer semantics rather than VIR_STRDUP might save some memory pressure.
+
+ if (mac && !leases_ret) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("no lease with matching MAC address: %s"), mac);
+ goto error;
+ }
+
+ if (leases_ret) {
+ /* NULL terminated array */
+ ignore_value(VIR_REALLOC_N(leases_ret, nleases + 1));
+ *leases = leases_ret;
+ leases_ret = NULL;
+ rv = nleases;
+ }
+
+cleanup:
+ VIR_FORCE_FCLOSE(fp);
+ VIR_FREE(leasefile);
+ return rv;
+
+error:
+ if (leases_ret) {
+ for (i = 0; i < nleases; i++)
+ virNetworkDHCPLeaseFree(leases_ret[i]);
+ }
+ VIR_FREE(leases_ret);
+ goto cleanup;
+}
+
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org