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[libvirt] [PATCHv4 3/4] net-dhcp-leases: Private implementation inside network driver



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 | 240 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 240 insertions(+)

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 8787bdb..e1c97c7 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -109,6 +109,29 @@ static int networkPlugBandwidth(virNetworkObjPtr net,
                                 virDomainNetDefPtr iface);
 static int networkUnplugBandwidth(virNetworkObjPtr net,
                                   virDomainNetDefPtr iface);
+/**
+ * VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX:
+ *
+ * Macro providing the upper limit on the size of leases file
+ */
+#define VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX 2097152
+
+/**
+ * VIR_NETWORK_DHCP_LEASE_FIELDS:
+ *
+ * Macro providing the maximum number of fields in an entry in
+ * the leases file
+ */
+#define VIR_NETWORK_DHCP_LEASE_FIELDS 5
+
+/**
+ * VIR_NETWORK_DHCP_LEASE_SEPARATOR_FIELDS:
+ *
+ * Macro providing the maximum number of fields in the separator
+ * line in the DHCPv6 leases file
+ */
+#define VIR_NETWORK_DHCP_LEASE_SEPARATOR_FIELDS 2
+
 
 static virNetworkDriverStatePtr driverState = NULL;
 
@@ -2988,6 +3011,221 @@ cleanup:
     return ret;
 }
 
+/* This function parses the leases file of dnsmasq.
+ *
+ * An example of DHCPv4 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 * *
+ *
+ * An example of DHCPv6 leases file content:
+ *
+ * 1380150262 52:54:00:2e:1d:22 192.168.122.80 * *
+ * 1380152517 52:54:00:72:0f:1e 192.168.122.119 * *
+ * duid 00:01:00:01:19:d3:ec:62:f0:4d:a2:8c:14:51
+ * 1380152445 3022114 2001:db8:ca2:2:1::92 * 00:01:00:01:19:d6:0c:59:52:54:00:2e:1d:22
+ * 1380152453 7474974 2001:db8:ca2:2:1::4e * 00:01:00:01:19:d5:e0:86:52:54:00:72:0f:1e
+ *
+ */
+static int
+networkGetDHCPLeasesHelper(virNetworkPtr network,
+                           virNetworkObjPtr obj,
+                           const char *mac,
+                           virNetworkDHCPLeasesPtr **leases)
+{
+    int rv = -1;
+    size_t i = 0;
+    size_t nleases = 0;
+    char *lease_file = NULL;
+    char **lease_fields = NULL;
+    char *lease_entries = NULL;
+    char *lease_entry = NULL;
+    virNetworkDHCPLeasesPtr *leases_ret = NULL;
+    virNetworkDHCPLeasesPtr lease = NULL;
+    int lease_file_len = 0;
+    bool ipv6 = false;
+    bool need_results = !!leases;
+
+    /* Retrieve leases file location */
+    lease_file = networkDnsmasqLeaseFileNameDefault(network->name);
+
+    if ((lease_file_len = virFileReadAll(lease_file,
+                                        VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX,
+                                        &lease_entries)) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Unable to read leases file: %s"), lease_file);
+        goto cleanup;
+    }
+
+    lease_entry = lease_entries[0] == '\0' ? NULL : lease_entries;
+
+    while (lease_entry) {
+        int nfields = 0;
+
+        char *eol = strchr(lease_entry, '\n');
+        *eol = '\0';
+
+        /* Split the lease line */
+        if (!(lease_fields = virStringSplit(lease_entry, " ",
+                                            VIR_NETWORK_DHCP_LEASE_FIELDS)))
+            goto error;
+
+        nfields = virStringListLength(lease_fields);
+
+        /* Forward lease_entry to the next lease */
+        lease_entry = strchr(lease_entry, '\0');
+        if (lease_entry - lease_entries + 1 < lease_file_len)
+            lease_entry++;
+        else
+            lease_entry = NULL;
+
+        /* Ignore the separator line in case of DHCPv6 */
+        if (nfields == VIR_NETWORK_DHCP_LEASE_SEPARATOR_FIELDS
+            && STREQ(lease_fields[0], "duid")) {
+            ipv6 = true;
+            virStringFreeList(lease_fields);
+            continue;
+        }
+
+        if (nfields != 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 && virMacAddrCompare(mac, lease_fields[1])) {
+            virStringFreeList(lease_fields);
+            continue;
+        }
+
+        if (need_results) {
+            if (VIR_ALLOC(lease) < 0)
+                goto error;
+
+            /* 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;
+            }
+
+            lease->type = ipv6 ? VIR_IP_ADDR_TYPE_IPV6 : VIR_IP_ADDR_TYPE_IPV4;
+            lease->prefix = virSocketAddrGetIpPrefix(&obj->def->ips->address,
+                                                     &obj->def->ips->netmask,
+                                                     obj->def->ips->prefix);
+
+            if ((VIR_STRDUP(lease->id.mac, lease_fields[1]) < 0) ||
+                (VIR_STRDUP(lease->ipaddr, lease_fields[2]) < 0))
+                goto error;
+
+            /* Only two fields, hostname and clientid can be NULL
+             * Refer: http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2013q3/007544.html
+             */
+            if (STREQ(lease_fields[3], "*"))
+                lease->hostname = NULL;
+            else if (VIR_STRDUP(lease->hostname, lease_fields[3]) < 0)
+                goto error;
+
+            if (STREQ(lease_fields[4], "*"))
+                lease->clientid = NULL;
+            else if (VIR_STRDUP(lease->clientid, lease_fields[4]) < 0)
+                goto error;
+
+            if (VIR_INSERT_ELEMENT(leases_ret, nleases, nleases, lease) < 0)
+                goto error;
+        }
+        else
+            nleases++;
+
+        VIR_FREE(lease);
+        virStringFreeList(lease_fields);
+    }
+
+    lease_fields = NULL;
+
+    if (need_results && 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:
+    if (lease)
+        VIR_FREE(lease);
+    VIR_FREE(lease_file);
+    VIR_FREE(lease_entries);
+    if (lease_fields)
+        virStringFreeList(lease_fields);
+    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",
@@ -3012,6 +3250,8 @@ 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


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