[libvirt] [PATCH v2] Add helper program to create custom leases
Nehal J Wani
nehaljw.kkd1 at gmail.com
Tue Jan 14 20:09:15 UTC 2014
Introduce helper program to catch events from dnsmasq and maintain a custom
lease file per network. It supports DHCPv4 and DHCPv6. The file is saved as
"<interface-name>.status".
The format of each lease is:
<expiry-time (epoch time)> <mac> <iaid> <ip-address> <hostname> <clientid>
Example of custom leases file content:
1385245780 52:54:00:2f:ba:76 * 192.168.150.153 * *
1385245781 52:54:00:2f:ba:76 3127926 2001:db8:ca2:2:1::6c * 00:04:76:00:cf:ae:b3:0b:fc:cd:0e:22:2e:97:76:65:74:ec
1385245964 52:54:00:44:7c:d7 * 192.168.150.219 iiit-ad885e4aa1 01:52:54:00:44:7c:d7
1385245964 52:54:00:44:7c:d7 * 192.168.150.219 * 01:52:54:00:44:7c:d7
1385246016 52:54:00:5d:99:92 * 192.168.150.212 iiit-ad885e4aa1 01:52:54:00:5d:99:92
1385246041 52:54:00:3b:16:e0 * 192.168.150.207 * *
1385246081 52:54:00:db:dd:98 * 192.168.150.234 * *
1385246088 52:54:00:db:dd:98 14409112 2001:db8:ca2:2:1::6d * 00:04:76:00:cf:ae:b3:0b:fc:cd:0e:22:2e:97:76:65:74:ec
---
As danpb suggested, I have split the previous patch into helper program & API
Refer: https://www.redhat.com/archives/libvir-list/2013-December/msg00694.html
Once this get ACKed, I'll send in the patches for the Leases API v6
src/Makefile.am | 20 ++++
src/network/bridge_driver.c | 4 +
src/util/leaseshelper.c | 225 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 249 insertions(+)
create mode 100644 src/util/leaseshelper.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 57e163f..6e5b03c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -838,6 +838,9 @@ STORAGE_HELPER_DISK_SOURCES = \
UTIL_IO_HELPER_SOURCES = \
util/iohelper.c
+UTIL_LEASES_HELPER_SOURCES = \
+ util/leaseshelper.c
+
# Network filters
NWFILTER_DRIVER_SOURCES = \
nwfilter/nwfilter_driver.h nwfilter/nwfilter_driver.c \
@@ -2408,6 +2411,23 @@ libvirt_iohelper_CFLAGS = \
$(NULL)
endif WITH_LIBVIRTD
+if WITH_LIBVIRTD
+libexec_PROGRAMS += libvirt_leaseshelper
+libvirt_leaseshelper_SOURCES = $(UTIL_LEASES_HELPER_SOURCES)
+libvirt_leaseshelper_LDFLAGS = \
+ $(NULL)
+libvirt_leaseshelper_LDADD = \
+ libvirt_util.la \
+ ../gnulib/lib/libgnu.la
+if WITH_DTRACE_PROBES
+libvirt_leaseshelper_LDADD += libvirt_probes.lo
+endif WITH_DTRACE_PROBES
+
+libvirt_leaseshelper_CFLAGS = \
+ $(PIE_CFLAGS) \
+ $(NULL)
+endif WITH_LIBVIRTD
+
if WITH_STORAGE_DISK
if WITH_LIBVIRTD
libexec_PROGRAMS += libvirt_parthelper
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 95e4b65..2278dba 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1063,6 +1063,10 @@ networkBuildDhcpDaemonCommandLine(virNetworkObjPtr network,
cmd = virCommandNew(dnsmasqCapsGetBinaryPath(caps));
virCommandAddArgFormat(cmd, "--conf-file=%s", configfile);
+
+ /* This helper is used to create cutom leases file for libvirt */
+ virCommandAddArgFormat(cmd, "--dhcp-script=%s", LIBEXECDIR "/libvirt_leaseshelper");
+
*cmdout = cmd;
ret = 0;
cleanup:
diff --git a/src/util/leaseshelper.c b/src/util/leaseshelper.c
new file mode 100644
index 0000000..486ebe3
--- /dev/null
+++ b/src/util/leaseshelper.c
@@ -0,0 +1,225 @@
+/*
+ * leasehelper.c: Helper program to create custom leases file
+ *
+ * Copyright (C) 2013 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Author: Nehal J Wani <nehaljw.kkd1 at gmail.com>
+ *
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "virutil.h"
+#include "virthread.h"
+#include "virfile.h"
+#include "virbuffer.h"
+#include "virstring.h"
+#include "virerror.h"
+#include "viralloc.h"
+#include "configmake.h"
+
+#define VIR_FROM_THIS VIR_FROM_NETWORK
+
+/**
+ * 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 6
+/**
+ * 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
+
+/*
+ * Use this when passing possibly-NULL strings to printf-a-likes.
+ */
+# define EMPTY_STR(s) ((s) ? (s) : "*")
+
+int
+main(int argc, char **argv) {
+
+ /* Doesn't hurt to check */
+ if (argc < 4) {
+ /* Refer man page of dnsmasq --dhcp-script for more details */
+ fprintf(stderr, "Usage: $program $action ${mac|clientid} $ip\n");
+ return -1;
+ }
+
+ const char *program_name = argv[0];
+ const char *action = argv[1];
+ const char *interface = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_INTERFACE"));
+ const char *expirytime = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_LEASE_EXPIRES"));
+ const char *mac = argv[2];
+ const char *ip = argv[3];
+ const char *iaid = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_IAID"));
+ const char *hostname = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_SUPPLIED_HOSTNAME"));
+ const char *clientid = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_CLIENT_ID"));
+ const char *leases_str = NULL;
+ char *lease_file = NULL;
+ char *lease_entries = NULL;
+ char *lease_entry = NULL;
+ char **lease_fields = NULL;
+ bool delete = false;
+ bool add = false;
+ int rv = -1;
+ int lease_file_len = 0;
+ FILE *fp = NULL;
+ long long expirytime_tmp = 0;
+ virBuffer buf_new_lease = VIR_BUFFER_INITIALIZER;
+ virBuffer buf_all_leases = VIR_BUFFER_INITIALIZER;
+
+ if (setlocale(LC_ALL, "") == NULL ||
+ bindtextdomain(PACKAGE, LOCALEDIR) == NULL ||
+ textdomain(PACKAGE) == NULL) {
+ fprintf(stderr, _("%s: initialization failed\n"), program_name);
+ exit(EXIT_FAILURE);
+ }
+
+ if (virThreadInitialize() < 0 ||
+ virErrorInitialize() < 0) {
+ fprintf(stderr, _("%s: initialization failed\n"), program_name);
+ exit(EXIT_FAILURE);
+ }
+
+ if (virAsprintf(&lease_file, "%s/%s.status", LOCALSTATEDIR
+ "/lib/libvirt/dnsmasq/", interface) < 0)
+ goto cleanup;
+
+ if (virGetEnvAllowSUID("DNSMASQ_IAID")) {
+ mac = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_MAC"));
+ clientid = argv[2];
+ }
+
+ /* Make sure dnsmasq knows the interface, otherwise something is wrong */
+ if (STREQ(interface, "*"))
+ goto cleanup;
+
+ /* Make sure the file exists. If not, 'touch' it */
+ if (virFileTouch(lease_file, 0644) < 0)
+ goto cleanup;
+
+ /* Read entire contents */
+ if ((lease_file_len = virFileReadAll(lease_file,
+ VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX,
+ &lease_entries)) < 0) {
+ goto cleanup;
+ }
+
+ if (STREQ(action, "add") || STREQ(action, "old") || STREQ(action, "del")) {
+ if (mac || STREQ(action, "del")) {
+ /* Delete the corresponding lease */
+ delete = true;
+ if (STREQ(action, "add") || STREQ(action, "old")) {
+ fprintf(stderr, "add|old\n");
+ add = true;
+ /* Enter new lease */
+ virBufferAsprintf(&buf_new_lease, "%s %s %s %s %s %s\n",
+ expirytime, mac, iaid, ip, hostname, clientid);
+
+ if (virBufferError(&buf_new_lease)) {
+ virBufferFreeAndReset(&buf_new_lease);
+ virReportOOMError();
+ 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 cleanup;
+
+ 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;
+
+ if (nfields != VIR_NETWORK_DHCP_LEASE_FIELDS)
+ goto cleanup;
+
+ if (virStrToLong_ll(lease_fields[0], NULL, 10, &expirytime_tmp) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Unable to convert lease expiry time to integer: %s"),
+ lease_fields[0]);
+ goto cleanup;
+ }
+
+ /* Check whether lease has expired or not */
+ if (expirytime_tmp < (long long) time(NULL))
+ continue;
+ else if (delete && STREQ(lease_fields[3], ip))
+ continue;
+ else {
+ virBufferAsprintf(&buf_all_leases, "%s %s %s %s %s %s\n",
+ lease_fields[0], lease_fields[1], lease_fields[2],
+ lease_fields[3], lease_fields[4], lease_fields[5]);
+
+ if (virBufferError(&buf_all_leases)) {
+ virBufferFreeAndReset(&buf_all_leases);
+ virReportOOMError();
+ goto cleanup;
+ }
+ }
+ }
+
+ if (add) {
+ virBufferAsprintf(&buf_all_leases, "%s", virBufferContentAndReset(&buf_new_lease));
+
+ if (virBufferError(&buf_all_leases)) {
+ virBufferFreeAndReset(&buf_all_leases);
+ virReportOOMError();
+ goto cleanup;
+ }
+ }
+
+ rv = 0;
+
+ /* Write to file */
+ leases_str = virBufferContentAndReset(&buf_all_leases);
+ if (!leases_str)
+ leases_str = "";
+
+ if (virFileWriteStr(lease_file, leases_str, 0) < 0)
+ rv = -1;
+
+cleanup:
+ VIR_FREE(lease_file);
+ VIR_FREE(lease_entries);
+ if (lease_fields)
+ virStringFreeList(lease_fields);
+ return rv;
+}
--
1.8.1.4
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