Re: [PATCH v5] Add helper program to create custom leases

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Ping!

On Sat, Apr 26, 2014 at 5:29 AM, Nehal J Wani <nehaljw.kkd1@xxxxxxxxx> wrote:
> 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
>
> ---
>  v5:
>  * More comments added, for better explanation
>  * Use of virFileFindResource() to identify proper path to helper binary
>  * Use of VIR_ENUM_IMPL for handling action events added
>
>  v4:
>  * Addition of pidfile and a corresponding lock for it
>  * Make correction for dnsmasq < 2.52 (Only IPv4)
>  * Move helper file from src/util to src/network
>  * Increase limit on max size of leases file
>  * Refer: https://www.redhat.com/archives/libvir-list/2014-March/msg01038.html
>
>  v3:
>  * Improved file handling, removed redundant copying, introduced --help and --version
>  * Refer: https://www.redhat.com/archives/libvir-list/2014-February/msg01431.html
>
>  v2:
>  * Changed format to JSON
>  * Refer: https://www.redhat.com/archives/libvir-list/2014-January/msg01234.html
>
>  v1:
>  * Refer: https://www.redhat.com/archives/libvir-list/2014-January/msg00626.html
>
>  src/Makefile.am             |   22 +++
>  src/network/bridge_driver.c |   27 ++++
>  src/network/leaseshelper.c  |  360 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 409 insertions(+), 0 deletions(-)
>  create mode 100644 src/network/leaseshelper.c
>
> diff --git a/src/Makefile.am b/src/Makefile.am
> index dd0abe7..fbe72c4 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -859,6 +859,9 @@ 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   \
> @@ -2466,6 +2469,25 @@ 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
> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
> index 201b22f..ade664d 100644
> --- a/src/network/bridge_driver.c
> +++ b/src/network/bridge_driver.c
> @@ -210,6 +210,16 @@ 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)
>  {
>      char *conffile;
> @@ -245,6 +255,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
>                        virNetworkObjPtr net)
>  {
>      char *leasefile = NULL;
> +    char *customleasefile = NULL;
>      char *radvdconfigfile = NULL;
>      char *configfile = NULL;
>      char *radvdpidbase = NULL;
> @@ -263,6 +274,9 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
>      if (!(leasefile = networkDnsmasqLeaseFileName(def->name)))
>          goto cleanup;
>
> +    if (!(customleasefile = networkDnsmasqLeaseFileNameCustom(def->bridge)))
> +        goto cleanup;
> +
>      if (!(radvdconfigfile = networkRadvdConfigFileName(def->name)))
>          goto cleanup;
>
> @@ -279,6 +293,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
>      /* dnsmasq */
>      dnsmasqDelete(dctx);
>      unlink(leasefile);
> +    unlink(customleasefile);
>      unlink(configfile);
>
>      /* radvd */
> @@ -296,6 +311,7 @@ networkRemoveInactive(virNetworkDriverStatePtr driver,
>   cleanup:
>      VIR_FREE(leasefile);
>      VIR_FREE(configfile);
> +    VIR_FREE(customleasefile);
>      VIR_FREE(radvdconfigfile);
>      VIR_FREE(radvdpidbase);
>      VIR_FREE(statusfile);
> @@ -1120,6 +1136,7 @@ networkBuildDhcpDaemonCommandLine(virNetworkObjPtr network,
>      int ret = -1;
>      char *configfile = NULL;
>      char *configstr = NULL;
> +    char *leaseshelper_path;
>
>      network->dnsmasqPid = -1;
>
> @@ -1142,11 +1159,21 @@ 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;
>  }
>
> diff --git a/src/network/leaseshelper.c b/src/network/leaseshelper.c
> new file mode 100644
> index 0000000..d580369
> --- /dev/null
> +++ b/src/network/leaseshelper.c
> @@ -0,0 +1,360 @@
> +/*
> + * leasehelper.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@xxxxxxxxx>
> + *
> + * 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;
> +}
> --
> 1.7.1
>



-- 
Nehal J Wani

--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list




[Index of Archives]     [Virt Tools]     [Libvirt Users]     [Lib OS Info]     [Fedora Users]     [Fedora Desktop]     [Fedora SELinux]     [Big List of Linux Books]     [Yosemite News]     [KDE Users]     [Fedora Tools]