[libvirt] [PATCHv3 3/4] net-dhcp-leases: Private implementation inside network driver

[Nehal J Wani]

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(+)

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 3a8be90..f5adb97 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -109,6 +109,21 @@ static int networkPlugBandwidth(virNetworkObjPtr net,
                                 virDomainNetDefPtr iface);
 static int networkUnplugBandwidth(virNetworkObjPtr net,
                                   virDomainNetDefPtr iface);
+/**
+ * VIR_NETWORK_DHCP_LEASE_LENGTH_MAX:
+ *
+ * Macro providing the maximum length of an entry in the leases file
+ * Refer: http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2013q3/007402.html
+ */
+#define VIR_NETWORK_DHCP_LEASE_LENGTH_MAX 2048
+
+/**
+ * VIR_NETWORK_DHCPLEASE_PARAMS:
+ *
+ * Macro providing the maximum number of parameters in an entry in
+ * the leases file
+ */
+#define VIR_NETWORK_DHCP_LEASE_FIELDS 5
 
 static virNetworkDriverStatePtr driverState = NULL;
 
@@ -2980,6 +2995,166 @@ cleanup:
     return ret;
 }
 
+/* This function parese the leases file of dnsmasq.
+ *
+ * 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;
+    }
+
+    /* 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) {
+        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]))
+            continue;
+
+        if (VIR_EXPAND_N(leases_ret, nleases, 1) < 0)
+            goto error;
+
+        if (VIR_ALLOC(leases_ret[nleases - 1]) < 0)
+            goto error;
+
+        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;
+    }
+
+    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;
+}
+
+static int
+networkGetDHCPLeases(virNetworkPtr network,
+                     virNetworkDHCPLeasesPtr **leases,
+                     unsigned int flags)
+{
+    int rv = -1;
+    virNetworkObjPtr obj;
+
+    virCheckFlags(0, -1);
+
+    if (!(obj = networkObjFromNetwork(network)))
+        return rv;
+
+    if (virNetworkGetDHCPLeasesEnsureACL(network->conn, obj->def) < 0)
+        goto cleanup;
+
+    rv = networkGetDHCPLeasesHelper(network, obj, NULL, leases);
+
+cleanup:
+    if (obj)
+        virNetworkObjUnlock(obj);
+    return rv;
+}
+
+static int
+networkGetDHCPLeasesForMAC(virNetworkPtr network,
+                           const char *mac,
+                           virNetworkDHCPLeasesPtr **leases,
+                           unsigned int flags)
+{
+    int rv = -1;
+    virNetworkObjPtr obj;
+
+    virCheckFlags(0, -1);
+
+    if (!(obj = networkObjFromNetwork(network)))
+        return rv;
+
+    if (virNetworkGetDHCPLeasesForMACEnsureACL(network->conn, obj->def) < 0)
+        goto cleanup;
+
+    rv = networkGetDHCPLeasesHelper(network, obj, mac, leases);
+
+cleanup:
+    if (obj)
+        virNetworkObjUnlock(obj);
+    return rv;
+}
 
 static virNetworkDriver networkDriver = {
     "Network",
@@ -3004,6 +3179,8 @@ static virNetworkDriver networkDriver = {
     .networkSetAutostart = networkSetAutostart, /* 0.2.1 */
     .networkIsActive = networkIsActive, /* 0.7.3 */
     .networkIsPersistent = networkIsPersistent, /* 0.7.3 */
+    .networkGetDHCPLeases = networkGetDHCPLeases, /* 1.1.3 */
+    .networkGetDHCPLeasesForMAC = networkGetDHCPLeasesForMAC, /* 1.1.3 */
 };
 
 static virStateDriver networkStateDriver = {
-- 
1.7.11.7