libvirt/src/network/leaseshelper.c

483 lines
17 KiB
C
Raw Normal View History

/*
* 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 <locale.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)
/*
* Use this when passing possibly-NULL strings to printf-a-likes.
* Required for unknown parameters during init call.
*/
#define EMPTY_STR(s) ((s) ? (s) : "*")
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|init 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_INIT, /* Tell dnsmasq of existing leases on restart */
VIR_LEASE_ACTION_LAST
};
VIR_ENUM_DECL(virLeaseAction);
VIR_ENUM_IMPL(virLeaseAction, VIR_LEASE_ACTION_LAST,
"add", "old", "del", "init");
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 *ip_tmp = NULL;
const char *leases_str = NULL;
const char *server_duid_tmp = 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 *server_duid = virGetEnvAllowSUID("DNSMASQ_SERVER_DUID");
long long currtime = 0;
long long expirytime = 0;
size_t i = 0;
int action = -1;
int pid_file_fd = -1;
int rv = EXIT_FAILURE;
int custom_lease_file_len = 0;
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 && argc != 2) {
/* 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
* via env variable set by dnsmasq when dnsmasq (re)starts and throws 'del'
* events for expired leases. So, libvirtd sets another env var for this
* purpose */
if (!interface &&
!(interface = virGetEnvAllowSUID("VIR_BRIDGE_NAME")))
goto cleanup;
ip = argv[3];
mac = argv[2];
if ((action = virLeaseActionTypeFromString(argv[1])) < 0) {
fprintf(stderr, _("Unsupported action: %s\n"), argv[1]);
exit(EXIT_FAILURE);
}
/* In case hostname is known, it is the 5th argument */
if (argc == 5)
hostname = argv[4];
/* In case hostname is still unknown, use the last known one */
if (!hostname)
hostname = virGetEnvAllowSUID("DNSMASQ_OLD_HOSTNAME");
if (exptime_tmp) {
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 (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;
}
switch ((enum virLeaseActionFlags) action) {
case VIR_LEASE_ACTION_ADD:
case VIR_LEASE_ACTION_OLD:
if (!mac)
break;
delete = true;
/* Create new lease */
if (!(lease_new = virJSONValueNewObject())) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
if (!exptime ||
virStrToLong_ll(exptime, NULL, 10, &expirytime) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unable to convert lease expiry time to long long: %s"),
NULLSTR(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 (server_duid && virJSONValueObjectAppendString(lease_new, "server-duid", server_duid) < 0)
goto cleanup;
if (expirytime && virJSONValueObjectAppendNumberLong(lease_new, "expiry-time", expirytime) < 0)
goto cleanup;
break;
case VIR_LEASE_ACTION_DEL:
delete = true;
/* 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) {
/* Delete the corresponding lease, if it already exists */
delete = true;
}
break;
case VIR_LEASE_ACTION_INIT:
case VIR_LEASE_ACTION_LAST:
break;
}
if (!(leases_array_new = virJSONValueNewArray())) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
currtime = (long long) time(NULL);
/* 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, rewriting it"),
custom_lease_file);
} else {
if (!virJSONValueIsArray(leases_array)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("couldn't fetch array of leases"));
goto cleanup;
}
i = 0;
while (i < virJSONValueArraySize(leases_array)) {
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) < 0)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to parse json"));
goto cleanup;
}
/* Check whether lease has expired or not */
if (expirytime < currtime) {
i++;
continue;
}
/* Check whether lease has to be included or not */
if (delete && STREQ(ip_tmp, ip)) {
i++;
continue;
}
if (strchr(ip_tmp, ':')) {
/* This is an ipv6 lease */
if ((server_duid_tmp
= virJSONValueObjectGetString(lease_tmp, "server-duid"))) {
if (!server_duid) {
/* Control reaches here when the 'action' is not for an
* ipv6 lease or, for some weird reason the env var
* DNSMASQ_SERVER_DUID wasn't set*/
server_duid = server_duid_tmp;
}
} else {
/* Inject server-duid into those ipv6 leases which
* didn't have it previously, for example, those
* created by leaseshelper from libvirt 1.2.6 */
if (virJSONValueObjectAppendString(lease_tmp, "server-duid", server_duid) < 0)
goto cleanup;
}
}
/* Move 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;
}
ignore_value(virJSONValueArraySteal(leases_array, i));
}
}
}
switch ((enum virLeaseActionFlags) action) {
case VIR_LEASE_ACTION_INIT:
/* Man page of dnsmasq says: the script (helper program, in our case)
* should write the saved state of the lease database, in dnsmasq
* leasefile format, to stdout and exit with zero exit code, when
* called with argument init. Format:
* $expirytime $mac $ip $hostname $clientid # For all ipv4 leases
* duid $server-duid # If DHCPv6 is present
* $expirytime $iaid $ip $hostname $clientduid # For all ipv6 leases */
/* Traversing the ipv4 leases */
for (i = 0; i < virJSONValueArraySize(leases_array_new); i++) {
lease_tmp = virJSONValueArrayGet(leases_array_new, i);
if (!(ip_tmp = virJSONValueObjectGetString(lease_tmp, "ip-address"))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to parse json"));
goto cleanup;
}
if (!strchr(ip_tmp, ':')) {
if (virJSONValueObjectGetNumberLong(lease_tmp, "expiry-time",
&expirytime) < 0)
continue;
printf("%lld %s %s %s %s\n",
expirytime,
virJSONValueObjectGetString(lease_tmp, "mac-address"),
virJSONValueObjectGetString(lease_tmp, "ip-address"),
EMPTY_STR(virJSONValueObjectGetString(lease_tmp, "hostname")),
EMPTY_STR(virJSONValueObjectGetString(lease_tmp, "client-id")));
}
}
/* Traversing the ipv6 leases */
if (server_duid) {
printf("duid %s\n", server_duid);
for (i = 0; i < virJSONValueArraySize(leases_array_new); i++) {
lease_tmp = virJSONValueArrayGet(leases_array_new, i);
if (!(ip_tmp = virJSONValueObjectGetString(lease_tmp, "ip-address"))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to parse json"));
goto cleanup;
}
if (strchr(ip_tmp, ':')) {
if (virJSONValueObjectGetNumberLong(lease_tmp, "expiry-time",
&expirytime) < 0)
continue;
printf("%lld %s %s %s %s\n",
expirytime,
virJSONValueObjectGetString(lease_tmp, "iaid"),
virJSONValueObjectGetString(lease_tmp, "ip-address"),
EMPTY_STR(virJSONValueObjectGetString(lease_tmp, "hostname")),
EMPTY_STR(virJSONValueObjectGetString(lease_tmp, "client-id")));
}
}
}
break;
case VIR_LEASE_ACTION_OLD:
case VIR_LEASE_ACTION_ADD:
if (virJSONValueArrayAppend(leases_array_new, lease_new) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("failed to create json"));
goto cleanup;
}
lease_new = NULL;
/* fallthrough */
case VIR_LEASE_ACTION_DEL:
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;
break;
case VIR_LEASE_ACTION_LAST:
break;
}
rv = EXIT_SUCCESS;
cleanup:
if (pid_file_fd != -1)
virPidFileReleasePath(pid_file, pid_file_fd);
VIR_FREE(pid_file);
VIR_FREE(exptime);
VIR_FREE(lease_entries);
VIR_FREE(custom_lease_file);
virJSONValueFree(lease_new);
virJSONValueFree(leases_array);
virJSONValueFree(leases_array_new);
return rv;
}