Active Directory dynamic DNS updates

https://fedorahosted.org/sssd/ticket/1504

Implements dynamic DNS updates for the AD provider. By default, the
updates also update the reverse zone and run periodically every 24
hours.

7 files changed, 402 insertions, 0 deletions

diff --git a/src/man/sssd-ad.5.xml b/src/man/sssd-ad.5.xml
index 95a95f1a..c1960771 100644
--- a/src/man/sssd-ad.5.xml
+++ b/src/man/sssd-ad.5.xml
@@ -152,6 +152,96 @@ ldap_id_mapping = False
                     </listitem>
                 </varlistentry>
 
+                <varlistentry>
+                    <term>dyndns_update (boolean)</term>
+                    <listitem>
+                        <para>
+                            Optional. This option tells SSSD to automatically
+                            update the Active Directory DNS server with
+                            the IP address of this client.
+                        </para>
+                        <para>
+                            NOTE: On older systems (such as RHEL 5), for this
+                            behavior to work reliably, the default Kerberos
+                            realm must be set properly in /etc/krb5.conf
+                        </para>
+                        <para>
+                            Default: false
+                        </para>
+                    </listitem>
+                </varlistentry>
+
+                <varlistentry>
+                    <term>dyndns_ttl (integer)</term>
+                    <listitem>
+                        <para>
+                            The TTL to apply to the client DNS record when updating it.
+                            If dyndns_update is false this has no effect. This will
+                            override the TTL serverside if set by an administrator.
+                        </para>
+                        <para>
+                            Default: 3600 (seconds)
+                        </para>
+                    </listitem>
+                </varlistentry>
+
+                <varlistentry>
+                    <term>dyndns_iface (string)</term>
+                    <listitem>
+                        <para>
+                            Optional. Applicable only when dyndns_update
+                            is true. Choose the interface whose IP address
+                            should be used for dynamic DNS updates.
+                        </para>
+                        <para>
+                            Default: Use the IP address of the IPA LDAP connection
+                        </para>
+                    </listitem>
+                </varlistentry>
+
+                <varlistentry>
+                    <term>dyndns_refresh_interval (integer)</term>
+                    <listitem>
+                        <para>
+                            How often should the back end perform periodic DNS update in
+                            addition to the automatic update performed when the back end
+                            goes online.
+                            This option is optional and applicable only when dyndns_update
+                            is true.
+                        </para>
+                        <para>
+                            Default: 86400 (24 hours)
+                        </para>
+                    </listitem>
+                </varlistentry>
+
+                <varlistentry>
+                    <term>dyndns_update_ptr (bool)</term>
+                    <listitem>
+                        <para>
+                            Whether the PTR record should also be explicitly
+                            updated when updating the client's DNS records.
+                            Applicable only when dyndns_update is true.
+                        </para>
+                        <para>
+                            Default: True
+                        </para>
+                    </listitem>
+                </varlistentry>
+
+                <varlistentry>
+                    <term>dyndns_force_tcp (bool)</term>
+                    <listitem>
+                        <para>
+                            Whether the nsupdate utility should default to using
+                            TCP for communicating with the DNS server.
+                        </para>
+                        <para>
+                            Default: False (let nsupdate choose the protocol)
+                        </para>
+                    </listitem>
+                </varlistentry>
+
                 <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="include/override_homedir.xml" />
 
                 <varlistentry>
diff --git a/src/providers/ad/ad_common.c b/src/providers/ad/ad_common.c
index dff1071d..e0a55c6d 100644
--- a/src/providers/ad/ad_common.c
+++ b/src/providers/ad/ad_common.c
@@ -23,6 +23,7 @@
 
 #include "providers/ad/ad_common.h"
 #include "providers/ad/ad_opts.h"
+#include "providers/dp_dyndns.h"
 
 errno_t
 ad_get_common_options(TALLOC_CTX *mem_ctx,
@@ -698,3 +699,20 @@ done:
     talloc_free(tmp_ctx);
     return ret;
 }
+
+errno_t ad_get_dyndns_options(struct be_ctx *be_ctx,
+                              struct ad_options *ad_opts)
+{
+    errno_t ret;
+
+    ret = be_nsupdate_init(ad_opts, be_ctx, ad_dyndns_opts, ad_dyndns_timer,
+                           ad_opts, &ad_opts->dyndns_ctx);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              ("Cannot initialize AD dyndns opts [%d]: %s\n",
+               ret, sss_strerror(ret)));
+        return ret;
+    }
+
+    return EOK;
+}
diff --git a/src/providers/ad/ad_common.h b/src/providers/ad/ad_common.h
index 7be15ba9..792f32e0 100644
--- a/src/providers/ad/ad_common.h
+++ b/src/providers/ad/ad_common.h
@@ -64,6 +64,10 @@ struct ad_options {
     /* Auth and chpass Provider */
     struct dp_option *auth;
     struct krb5_ctx *auth_ctx;
+
+    /* Dynamic DNS updates */
+    struct be_resolv_ctx *be_res;
+    struct be_nsupdate_ctx *dyndns_ctx;
 };
 
 errno_t
@@ -91,4 +95,13 @@ ad_get_auth_options(TALLOC_CTX *mem_ctx,
                     struct be_ctx *bectx,
                     struct dp_option **_opts);
 
+errno_t
+ad_get_dyndns_options(struct be_ctx *be_ctx,
+                      struct ad_options *ad_opts);
+
+/* AD dynamic DNS updates */
+errno_t ad_dyndns_init(struct be_ctx *be_ctx,
+                       struct ad_options *ctx);
+void ad_dyndns_timer(void *pvt);
+
 #endif /* AD_COMMON_H_ */
diff --git a/src/providers/ad/ad_dyndns.c b/src/providers/ad/ad_dyndns.c
new file mode 100644
index 00000000..2b2d2462
--- /dev/null
+++ b/src/providers/ad/ad_dyndns.c
@@ -0,0 +1,256 @@
+/*
+    SSSD
+
+    ad_dyndns.c
+
+    Authors:
+        Jakub Hrozek <jhrozek@redhat.com>
+
+    Copyright (C) 2013 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <ctype.h>
+#include "util/util.h"
+#include "providers/ldap/sdap_dyndns.h"
+#include "providers/data_provider.h"
+#include "providers/dp_dyndns.h"
+#include "providers/ad/ad_common.h"
+
+void ad_dyndns_update(void *pvt);
+
+errno_t ad_dyndns_init(struct be_ctx *be_ctx,
+                       struct ad_options *ad_opts)
+{
+    errno_t ret;
+
+    /* nsupdate is available. Dynamic updates
+     * are supported
+     */
+    ret = ad_get_dyndns_options(be_ctx, ad_opts);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Could not set AD options\n"));
+        return ret;
+    }
+
+    if (dp_opt_get_bool(ad_opts->dyndns_ctx->opts,
+                        DP_OPT_DYNDNS_UPDATE) == false) {
+        DEBUG(SSSDBG_CONF_SETTINGS, ("Dynamic DNS updates not set\n"));
+        return EOK;
+    }
+
+    DEBUG(SSSDBG_CONF_SETTINGS,
+          ("Dynamic DNS updates are on. Checking for nsupdate..\n"));
+    ret = be_nsupdate_check();
+    if (ret == ENOENT) {
+        DEBUG(SSSDBG_MINOR_FAILURE,
+              ("DNS updates requested but nsupdate not available\n"));
+        return EOK;
+    } else if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE, ("Could not check for nsupdate\n"));
+        return ret;
+    }
+
+    ad_opts->be_res = be_ctx->be_res;
+    if (ad_opts->be_res == NULL) {
+        DEBUG(SSSDBG_OP_FAILURE, ("Resolver must be initialized in order "
+              "to use the AD dynamic DNS updates\n"));
+        return EINVAL;
+    }
+
+    ret = be_add_online_cb(be_ctx, be_ctx,
+                           ad_dyndns_update,
+                           ad_opts, NULL);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Could not set up online callback\n"));
+        return ret;
+    }
+
+    return EOK;
+}
+
+static void ad_dyndns_timer_connected(struct tevent_req *req);
+
+void ad_dyndns_timer(void *pvt)
+{
+    struct ad_options *ctx = talloc_get_type(pvt, struct ad_options);
+    struct sdap_id_ctx *sdap_ctx = ctx->id_ctx->sdap_id_ctx;
+    struct tevent_req *req;
+
+    req = sdap_dyndns_timer_conn_send(ctx, sdap_ctx->be->ev, sdap_ctx,
+                                      ctx->dyndns_ctx);
+    if (req == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Out of memory\n"));
+        /* Not much we can do. Just attempt to reschedule */
+        be_nsupdate_timer_schedule(sdap_ctx->be->ev, ctx->dyndns_ctx);
+        return;
+    }
+    tevent_req_set_callback(req, ad_dyndns_timer_connected, ctx);
+}
+
+static void ad_dyndns_timer_connected(struct tevent_req *req)
+{
+    errno_t ret;
+    struct ad_options *ctx = tevent_req_callback_data(req, struct ad_options);
+
+    ret = sdap_dyndns_timer_conn_recv(req);
+    talloc_zfree(req);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              ("Failed to connect to AD: [%d](%s)\n", ret, sss_strerror(ret)));
+        return;
+    }
+
+    return ad_dyndns_update(ctx);
+}
+
+static struct tevent_req *ad_dyndns_update_send(struct ad_options *ctx);
+static errno_t ad_dyndns_update_recv(struct tevent_req *req);
+static void ad_dyndns_nsupdate_done(struct tevent_req *req);
+
+void ad_dyndns_update(void *pvt)
+{
+    struct ad_options *ctx = talloc_get_type(pvt, struct ad_options);
+    struct sdap_id_ctx *sdap_ctx = ctx->id_ctx->sdap_id_ctx;
+    struct tevent_req *req;
+
+    /* Schedule timer after provider went offline */
+    be_nsupdate_timer_schedule(sdap_ctx->be->ev, ctx->dyndns_ctx);
+
+    req = ad_dyndns_update_send(ctx);
+    if (req == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Could not update DNS\n"));
+        return;
+    }
+    tevent_req_set_callback(req, ad_dyndns_nsupdate_done, NULL);
+}
+
+static void ad_dyndns_nsupdate_done(struct tevent_req *req)
+{
+    int ret = ad_dyndns_update_recv(req);
+    talloc_free(req);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE, ("Updating DNS entry failed [%d]: %s\n",
+              ret, sss_strerror(ret)));
+        return;
+    }
+
+    DEBUG(SSSDBG_OP_FAILURE, ("DNS update finished\n"));
+}
+
+struct ad_dyndns_update_state {
+    struct ad_options *ad_ctx;
+};
+
+static void ad_dyndns_sdap_update_done(struct tevent_req *subreq);
+
+static struct tevent_req *
+ad_dyndns_update_send(struct ad_options *ctx)
+{
+    int ret;
+    struct ad_dyndns_update_state *state;
+    struct tevent_req *req, *subreq;
+    struct sdap_id_ctx *sdap_ctx = ctx->id_ctx->sdap_id_ctx;
+    const char *servername;
+
+    DEBUG(SSSDBG_TRACE_FUNC, ("Performing update\n"));
+
+    req = tevent_req_create(ctx, &state, struct ad_dyndns_update_state);
+    if (req == NULL) {
+        return NULL;
+    }
+    state->ad_ctx = ctx;
+
+    if (ctx->dyndns_ctx->last_refresh + 60 > time(NULL) ||
+        ctx->dyndns_ctx->timer_in_progress) {
+        DEBUG(SSSDBG_FUNC_DATA, ("Last periodic update ran recently or timer"
+              "in progress, not scheduling another update\n"));
+        tevent_req_done(req);
+        tevent_req_post(req, sdap_ctx->be->ev);
+        return req;
+    }
+    state->ad_ctx->dyndns_ctx->last_refresh = time(NULL);
+
+    if (strncmp(ctx->service->sdap->uri,
+                "ldap://", 7) != 0) {
+        DEBUG(SSSDBG_CRIT_FAILURE, ("Unexpected format of LDAP URI.\n"));
+        ret = EIO;
+        goto done;
+    }
+    servername = ctx->service->sdap->uri + 7;
+    if (!servername) {
+        ret = EIO;
+        goto done;
+    }
+
+    subreq = sdap_dyndns_update_send(state, sdap_ctx->be->ev,
+                                     sdap_ctx->be,
+                                     ctx->dyndns_ctx->opts,
+                                     sdap_ctx,
+                                     ctx->dyndns_ctx->auth_type,
+                                     dp_opt_get_string(ctx->dyndns_ctx->opts,
+                                                       DP_OPT_DYNDNS_IFACE),
+                                     dp_opt_get_string(ctx->basic,
+                                                       AD_HOSTNAME),
+                                     NULL,
+                                     dp_opt_get_string(ctx->basic,
+                                                       AD_KRB5_REALM),
+                                     servername,
+                                     dp_opt_get_int(ctx->dyndns_ctx->opts,
+                                                    DP_OPT_DYNDNS_TTL),
+                                     false);
+    if (!subreq) {
+        ret = EIO;
+        DEBUG(SSSDBG_OP_FAILURE,
+              ("sdap_id_op_connect_send failed: [%d](%s)\n",
+               ret, sss_strerror(ret)));
+        goto done;
+    }
+    tevent_req_set_callback(subreq, ad_dyndns_sdap_update_done, req);
+
+    ret = EOK;
+done:
+    if (ret != EOK) {
+        tevent_req_error(req, ret);
+        tevent_req_post(req, sdap_ctx->be->ev);
+    }
+    return req;
+}
+
+static void ad_dyndns_sdap_update_done(struct tevent_req *subreq)
+{
+    struct tevent_req *req = tevent_req_callback_data(subreq,
+                                                      struct tevent_req);
+    errno_t ret;
+
+    ret = sdap_dyndns_update_recv(subreq);
+    talloc_zfree(subreq);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              ("Dynamic DNS update failed [%d]: %s\n",
+              ret, sss_strerror(ret)));
+        tevent_req_error(req, ret);
+        return;
+    }
+
+    tevent_req_done(req);
+}
+
+static errno_t ad_dyndns_update_recv(struct tevent_req *req)
+{
+    TEVENT_REQ_RETURN_ON_ERROR(req);
+
+    return EOK;
+}
diff --git a/src/providers/ad/ad_init.c b/src/providers/ad/ad_init.c
index 4d109868..7ebe2a0e 100644
--- a/src/providers/ad/ad_init.c
+++ b/src/providers/ad/ad_init.c
@@ -36,6 +36,7 @@
 #include "providers/krb5/krb5_init_shared.h"
 #include "providers/ad/ad_id.h"
 #include "providers/ad/ad_srv.h"
+#include "providers/dp_dyndns.h"
 
 struct ad_options *ad_options = NULL;
 
@@ -166,6 +167,13 @@ sssm_ad_id_init(struct be_ctx *bectx,
         if (ret != EOK) goto done;
     }
 
+    ret = ad_dyndns_init(sdap_ctx->be, ad_options);
+    if (ret != EOK) {
+        DEBUG(SSSDBG_MINOR_FAILURE,
+             ("Failure setting up automatic DNS update\n"));
+        /* Continue without DNS updates */
+    }
+
     ret = sdap_id_setup_tasks(sdap_ctx);
     if (ret != EOK) {
         goto done;
diff --git a/src/providers/ad/ad_opts.h b/src/providers/ad/ad_opts.h
index c48be867..32bbe3db 100644
--- a/src/providers/ad/ad_opts.h
+++ b/src/providers/ad/ad_opts.h
@@ -238,4 +238,15 @@ struct sdap_attr_map ad_autofs_entry_map[] = {
     SDAP_ATTR_MAP_TERMINATOR
 };
 
+struct dp_option ad_dyndns_opts[] = {
+    { "dyndns_update", DP_OPT_BOOL, BOOL_FALSE, BOOL_FALSE },
+    { "dyndns_refresh_interval", DP_OPT_NUMBER, { .number = 86400 }, NULL_NUMBER },
+    { "dyndns_iface", DP_OPT_STRING, NULL_STRING, NULL_STRING },
+    { "dyndns_ttl", DP_OPT_NUMBER, { .number = 3600 }, NULL_NUMBER },
+    { "dyndns_update_ptr", DP_OPT_BOOL, BOOL_TRUE, BOOL_FALSE },
+    { "dyndns_force_tcp", DP_OPT_BOOL, BOOL_FALSE, BOOL_FALSE },
+    { "dyndns_auth", DP_OPT_STRING, { "gss-tsig" }, NULL_STRING },
+    DP_OPTION_TERMINATOR
+};
+
 #endif /* AD_OPTS_H_ */
diff --git a/src/tests/ipa_ldap_opt-tests.c b/src/tests/ipa_ldap_opt-tests.c
index d1a96dc8..ea4991c8 100644
--- a/src/tests/ipa_ldap_opt-tests.c
+++ b/src/tests/ipa_ldap_opt-tests.c
@@ -32,6 +32,8 @@
 #include "providers/ldap/ldap_opts.h"
 #include "providers/krb5/krb5_opts.h"
 #include "providers/krb5/krb5_common.h"
+#include "providers/ad/ad_opts.h"
+#include "providers/dp_dyndns.h"
 #include "tests/common.h"
 
 struct test_domain {
@@ -88,6 +90,10 @@ START_TEST(test_compare_opts)
     ret = compare_dp_options(default_krb5_opts, KRB5_OPTS,
                              ipa_def_krb5_opts);
     fail_unless(ret == EOK, "[%s]", strerror(ret));
+
+    ret = compare_dp_options(ipa_dyndns_opts, DP_OPT_DYNDNS,
+                             ad_dyndns_opts);
+    fail_unless(ret == EOK, "[%s]", strerror(ret));
 }
 END_TEST