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Add helper program to create custom leases

Browse Source 
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".

Each lease contains the following info:
<expiry-time (epoch time)> <mac> <iaid> <ip-address> <hostname> <clientid>

Example of custom leases file content:
[
    {
        "iaid": "1221229",
        "ip-address": "2001:db8:ca2:2:1::95",
        "mac-address": "52:54:00:12:a2:6d",
        "hostname": "Fedora20",
        "client-id": "00:04:1a:c1:d9:6b:5a:0a:e2:bc:f8:4b:1e:37:2e:38:22:55",
        "expiry-time": 1393244216
    },
    {
        "ip-address": "192.168.150.208",
        "mac-address": "52:54:00:11:56:b3",
        "hostname": "Wani-PC",
        "client-id": "01:52:54:00:11:56:b3",
        "expiry-time": 1393244248
    }
]

src/Makefile.am:
   * Add options to compile the helper program

src/network/bridge_driver.c:
   * Introduce networkDnsmasqLeaseFileNameCustom()
   * Invoke helper program along with dnsmasq
   * Delete the .status file when corresponding n/w is destroyed.

src/network/leaseshelper.c
   * Helper program to create the custom lease file
This commit is contained in:
Nehal J Wani 2014-06-02 11:19:26 +01:00 committed by Daniel P. Berrange
parent 6ef0b03483
commit baafe668fa
5 changed files with 412 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
libvirt.spec.in
View File

@ -1917,6 +1917,7 @@ exit 0
%dir %attr(0700, root, root) %{_sysconfdir}/libvirt/qemu/networks/autostart
%dir %attr(0700, root, root) %{_localstatedir}/lib/libvirt/network/
%dir %attr(0755, root, root) %{_localstatedir}/lib/libvirt/dnsmasq/
%attr(0755, root, root) %{_libexecdir}/libvirt_leaseshelper
%endif
%if %{with_nwfilter}
%dir %attr(0700, root, root) %{_sysconfdir}/libvirt/nwfilter/
@ -1992,6 +1993,7 @@ exit 0
%ghost %dir %{_localstatedir}/run/libvirt/network/
%dir %attr(0700, root, root) %{_localstatedir}/lib/libvirt/network/
%dir %attr(0755, root, root) %{_localstatedir}/lib/libvirt/dnsmasq/
%attr(0755, root, root) %{_libexecdir}/libvirt_leaseshelper
%{_libdir}/%{name}/connection-driver/libvirt_driver_network.so
%endif

1
po/POTFILES.in
View File

@ -76,6 +76,7 @@ src/libxl/libxl_driver.c
src/libxl/libxl_conf.c
src/network/bridge_driver.c
src/network/bridge_driver_linux.c
src/network/leaseshelper.c
src/node_device/node_device_driver.c
src/node_device/node_device_hal.c
src/node_device/node_device_linux_sysfs.c

22
src/Makefile.am
View File

@ -860,6 +860,9 @@ STORAGE_HELPER_DISK_SOURCES = \
UTIL_IO_HELPER_SOURCES = \
util/iohelper.c
NETWORK_LEASES_HELPER_SOURCES = \
network/leaseshelper.c
# Network filters
NWFILTER_DRIVER_SOURCES = \
nwfilter/nwfilter_driver.h nwfilter/nwfilter_driver.c \
@ -2468,6 +2471,25 @@ libvirt_iohelper_CFLAGS = \
$(AM_CFLAGS) \
$(PIE_CFLAGS) \
$(NULL)
if WITH_NETWORK
libexec_PROGRAMS += libvirt_leaseshelper
libvirt_leaseshelper_SOURCES = $(NETWORK_LEASES_HELPER_SOURCES)
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 = \
$(AM_CFLAGS) \
$(PIE_CFLAGS) \
$(NULL)
else ! WITH_NETWORK
EXTRA_DIST += $(NETWORK_LEASES_HELPER_SOURCES)
endif ! WITH_NETWORK
endif WITH_LIBVIRTD
if WITH_STORAGE_DISK

27
src/network/bridge_driver.c
View File

@ -210,6 +210,16 @@ networkDnsmasqLeaseFileNameDefault(const char *netname)
networkDnsmasqLeaseFileNameFunc networkDnsmasqLeaseFileName =
networkDnsmasqLeaseFileNameDefault;
static char *
networkDnsmasqLeaseFileNameCustom(const char *bridge)
{
char *leasefile;
ignore_value(virAsprintf(&leasefile, "%s/%s.status",
driverState->dnsmasqStateDir, bridge));
return leasefile;
}
static char *
networkDnsmasqConfigFileName(const char *netname)
{
@ -246,6 +256,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
virNetworkObjPtr net)
{
char *leasefile = NULL;
char *customleasefile = NULL;
char *radvdconfigfile = NULL;
char *configfile = NULL;
char *radvdpidbase = NULL;
@ -264,6 +275,9 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
if (!(leasefile = networkDnsmasqLeaseFileName(def->name)))
goto cleanup;
if (!(customleasefile = networkDnsmasqLeaseFileNameCustom(def->bridge)))
goto cleanup;
if (!(radvdconfigfile = networkRadvdConfigFileName(def->name)))
goto cleanup;
@ -280,6 +294,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
/* dnsmasq */
dnsmasqDelete(dctx);
unlink(leasefile);
unlink(customleasefile);
unlink(configfile);
/* radvd */
@ -297,6 +312,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
cleanup:
VIR_FREE(leasefile);
VIR_FREE(configfile);
VIR_FREE(customleasefile);
VIR_FREE(radvdconfigfile);
VIR_FREE(radvdpidbase);
VIR_FREE(statusfile);
@ -1236,6 +1252,7 @@ networkBuildDhcpDaemonCommandLine(virNetworkObjPtr network,
int ret = -1;
char *configfile = NULL;
char *configstr = NULL;
char *leaseshelper_path;
network->dnsmasqPid = -1;
@ -1258,11 +1275,21 @@ networkBuildDhcpDaemonCommandLine(virNetworkObjPtr network,
cmd = virCommandNew(dnsmasqCapsGetBinaryPath(caps));
virCommandAddArgFormat(cmd, "--conf-file=%s", configfile);
/* This helper is used to create custom leases file for libvirt */
if (!(leaseshelper_path = virFileFindResource("libvirt_leaseshelper",
"src",
LIBEXECDIR)))
goto cleanup;
virCommandAddArgFormat(cmd, "--dhcp-script=%s", leaseshelper_path);
*cmdout = cmd;
ret = 0;
cleanup:
VIR_FREE(configfile);
VIR_FREE(configstr);
VIR_FREE(leaseshelper_path);
return ret;
}

360
src/network/leaseshelper.c Normal file
View File

@ -0,0 +1,360 @@
/*
* leaseshelper.c: Helper program to create custom leases file
*
* Copyright (C) 2014 Red Hat, Inc.
* Copyright (C) 2014 Nehal J Wani
*
* 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@gmail.com>
*
* For IPv6 support, use dnsmasq >= 2.67
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "virutil.h"
#include "virthread.h"
#include "virfile.h"
#include "virpidfile.h"
#include "virbuffer.h"
#include "virstring.h"
#include "virerror.h"
#include "viralloc.h"
#include "virjson.h"
#include "configmake.h"
#define VIR_FROM_THIS VIR_FROM_NETWORK
/**
* 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 (32 * 1024 * 1024)
static const char *program_name;
/* Display version information. */
static void
helperVersion(const char *argv0)
{
printf("%s (%s) %s\n", argv0, PACKAGE_NAME, PACKAGE_VERSION);
}
ATTRIBUTE_NORETURN static void
usage(int status)
{
if (status) {
fprintf(stderr, _("%s: try --help for more details\n"), program_name);
} else {
printf(_("Usage: %s add|old|del mac|clientid ip [hostname]\n"
"Designed for use with 'dnsmasq --dhcp-script'\n"
"Refer to man page of dnsmasq for more details'\n"),
program_name);
}
exit(status);
}
static int
customLeaseRewriteFile(int fd, void *opaque)
{
char **data = opaque;
if (safewrite(fd, *data, strlen(*data)) < 0)
return -1;
return 0;
}
/* Flags denoting actions for a lease */
enum virLeaseActionFlags {
VIR_LEASE_ACTION_ADD, /* Create new lease */
VIR_LEASE_ACTION_OLD, /* Lease already exists, renew it */
VIR_LEASE_ACTION_DEL, /* Delete the lease */
VIR_LEASE_ACTION_LAST
};
VIR_ENUM_DECL(virLeaseAction);
VIR_ENUM_IMPL(virLeaseAction, VIR_LEASE_ACTION_LAST,
"add", "old", "del");
int
main(int argc, char **argv)
{
char *exptime = NULL;
char *pid_file = NULL;
char *lease_entries = NULL;
char *custom_lease_file = NULL;
const char *ip = NULL;
const char *mac = NULL;
const char *iaid = virGetEnvAllowSUID("DNSMASQ_IAID");
const char *clientid = virGetEnvAllowSUID("DNSMASQ_CLIENT_ID");
const char *interface = virGetEnvAllowSUID("DNSMASQ_INTERFACE");
const char *exptime_tmp = virGetEnvAllowSUID("DNSMASQ_LEASE_EXPIRES");
const char *hostname = virGetEnvAllowSUID("DNSMASQ_SUPPLIED_HOSTNAME");
const char *leases_str = NULL;
long long currtime = 0;
long long expirytime = 0;
size_t i = 0;
int size = 0;
int action = -1;
int pid_file_fd = -1;
int rv = EXIT_FAILURE;
int custom_lease_file_len = 0;
bool add = false;
bool delete = false;
virJSONValuePtr lease_new = NULL;
virJSONValuePtr lease_tmp = NULL;
virJSONValuePtr leases_array = NULL;
virJSONValuePtr leases_array_new = NULL;
virSetErrorFunc(NULL, NULL);
virSetErrorLogPriorityFunc(NULL);
program_name = argv[0];
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);
}
/* Doesn't hurt to check */
if (argc > 1) {
if (STREQ(argv[1], "--help"))
usage(EXIT_SUCCESS);
if (STREQ(argv[1], "--version")) {
helperVersion(argv[0]);
exit(EXIT_SUCCESS);
}
}
if (argc != 4 && argc != 5) {
/* Refer man page of dnsmasq --dhcp-script for more details */
usage(EXIT_FAILURE);
}
/* Make sure dnsmasq knows the interface. The interface name is not known
* when dnsmasq (re)starts and throws 'del' events for expired leases.
* So, if any old lease has expired, it will be automatically removed the
* next time this program is invoked */
if (!interface)
goto cleanup;
ip = argv[3];
mac = argv[2];
action = virLeaseActionTypeFromString(argv[1]);
/* In case hostname is known, it is the 5th argument */
if (argc == 5)
hostname = argv[4];
if (VIR_STRDUP(exptime, exptime_tmp) < 0)
goto cleanup;
/* Removed extraneous trailing space in DNSMASQ_LEASE_EXPIRES (dnsmasq < 2.52) */
if (exptime[strlen(exptime) - 1] == ' ')
exptime[strlen(exptime) - 1] = '\0';
/* Check if it is an IPv6 lease */
if (virGetEnvAllowSUID("DNSMASQ_IAID")) {
mac = virGetEnvAllowSUID("DNSMASQ_MAC");
clientid = argv[2];
}
if (virAsprintf(&custom_lease_file,
LOCALSTATEDIR "/lib/libvirt/dnsmasq/%s.status",
interface) < 0)
goto cleanup;
if (VIR_STRDUP(pid_file, LOCALSTATEDIR "/run/leaseshelper.pid") < 0)
goto cleanup;
/* Try to claim the pidfile, exiting if we can't */
if ((pid_file_fd = virPidFileAcquirePath(pid_file, true, getpid())) < 0)
goto cleanup;
/* Since interfaces can be hot plugged, we need to make sure that the
* corresponding custom lease file exists. If not, 'touch' it */
if (virFileTouch(custom_lease_file, 0644) < 0)
goto cleanup;
/* Read entire contents */
if ((custom_lease_file_len = virFileReadAll(custom_lease_file,
VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX,
&lease_entries)) < 0) {
goto cleanup;
}
if (action == VIR_LEASE_ACTION_ADD ||
action == VIR_LEASE_ACTION_OLD ||
action == VIR_LEASE_ACTION_DEL) {
/* Custom ipv6 leases *will not* be created if the env-var DNSMASQ_MAC
* is not set. In the special case, when the $(interface).status file
* is not already present and dnsmasq is (re)started, the corresponding
* ipv6 custom lease will be created only when the guest sends the
* 'old' action for its existing ipv6 interfaces.
*
* According to rfc3315, the combination of DUID and IAID can be used
* to uniquely identify each ipv6 guest interface. So, in future, if
* we introduce virNetworkGetDHCPLeaseBy(IAID|DUID|IAID+DUID) for ipv6
* interfaces, then, the following if condition won't be required, as
* the new lease will be created irrespective of whether the MACID is
* known or not.
*/
if (mac || action == VIR_LEASE_ACTION_DEL) {
/* Delete the corresponding lease, if it already exists */
delete = true;
if (action == VIR_LEASE_ACTION_ADD ||
action == VIR_LEASE_ACTION_OLD) {
add = true;
/* Create new lease */
if (!(lease_new = virJSONValueNewObject())) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
if (virStrToLong_ll(exptime, NULL, 10, &expirytime) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unable to convert lease expiry time to long long: %s"),
exptime);
goto cleanup;
}
if (iaid && virJSONValueObjectAppendString(lease_new, "iaid", iaid) < 0)
goto cleanup;
if (ip && virJSONValueObjectAppendString(lease_new, "ip-address", ip) < 0)
goto cleanup;
if (mac && virJSONValueObjectAppendString(lease_new, "mac-address", mac) < 0)
goto cleanup;
if (hostname && virJSONValueObjectAppendString(lease_new, "hostname", hostname) < 0)
goto cleanup;
if (clientid && virJSONValueObjectAppendString(lease_new, "client-id", clientid) < 0)
goto cleanup;
if (expirytime && virJSONValueObjectAppendNumberLong(lease_new, "expiry-time", expirytime) < 0)
goto cleanup;
}
}
} else {
fprintf(stderr, _("Unsupported action: %s\n"),
virLeaseActionTypeToString(action));
exit(EXIT_FAILURE);
}
/* Check for previous leases */
if (custom_lease_file_len) {
if (!(leases_array = virJSONValueFromString(lease_entries))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("invalid json in file: %s"), custom_lease_file);
goto cleanup;
}
if ((size = virJSONValueArraySize(leases_array)) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("couldn't fetch array of leases"));
goto cleanup;
}
}
if (!(leases_array_new = virJSONValueNewArray())) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
currtime = (long long) time(NULL);
for (i = 0; i < size; i++) {
const char *ip_tmp = NULL;
long long expirytime_tmp = -1;
if (!(lease_tmp = virJSONValueArrayGet(leases_array, i))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to parse json"));
goto cleanup;
}
if (!(ip_tmp = virJSONValueObjectGetString(lease_tmp, "ip-address")) ||
(virJSONValueObjectGetNumberLong(lease_tmp, "expiry-time", &expirytime_tmp) < 0)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to parse json"));
goto cleanup;
}
/* Check whether lease has expired or not */
if (expirytime_tmp < currtime)
continue;
/* Check whether lease has to be included or not */
if (delete && STREQ(ip_tmp, ip))
continue;
/* Add old lease to new array */
if (virJSONValueArrayAppend(leases_array_new, lease_tmp) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
}
if (add) {
if (virJSONValueArrayAppend(leases_array_new, lease_new) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
}
if (!(leases_str = virJSONValueToString(leases_array_new, true))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("empty json array"));
goto cleanup;
}
/* Write to file */
if (virFileRewrite(custom_lease_file, 0644,
customLeaseRewriteFile, &leases_str) < 0)
goto cleanup;
rv = EXIT_SUCCESS;
cleanup:
if (pid_file_fd != -1)
virPidFileReleasePath(pid_file, pid_file_fd);
VIR_FREE(pid_file);
VIR_FREE(exptime_tmp);
VIR_FREE(custom_lease_file);
virJSONValueFree(lease_new);
virJSONValueFree(leases_array);
virJSONValueFree(leases_array_new);
return rv;
}