dfs_server: add generic dfs_server_ad_get_referrals() call

This is a generic function to implement the domain, dc and sysvol
DFS referrals.

metze

4 files changed, 878 insertions, 0 deletions

diff --git a/dfs_server/dfs_server_ad.c b/dfs_server/dfs_server_ad.c
new file mode 100644
index 00000000000..22d3263b03b
--- /dev/null
+++ b/dfs_server/dfs_server_ad.c
@@ -0,0 +1,847 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Copyright Matthieu Patou <mat@matws.net> 2010-2011
+   Copyright Stefan Metzmacher 2011
+
+   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 "includes.h"
+#include "librpc/gen_ndr/dfsblobs.h"
+#include "librpc/gen_ndr/ndr_dfsblobs.h"
+#include "dsdb/samdb/samdb.h"
+#include "auth/session.h"
+#include "param/param.h"
+#include "lib/tsocket/tsocket.h"
+#include "dfs_server/dfs_server_ad.h"
+
+#define MAX_DFS_RESPONSE 56*1024 /* 56 Kb */
+
+/* A DC set is a group of DC, they might have been grouped together
+   because they belong to the same site, or to site with same cost ...
+*/
+struct dc_set {
+	const char **names;
+	uint32_t count;
+};
+
+/*
+  fill a referral type structure
+ */
+static NTSTATUS fill_normal_dfs_referraltype(TALLOC_CTX *mem_ctx,
+					     struct dfs_referral_type *ref,
+					     uint16_t version,
+					     const char *dfs_path,
+					     const char *server_path, int isfirstoffset)
+{
+	ZERO_STRUCTP(ref);
+	switch (version) {
+	case 4:
+		version = 3;
+# if 0
+		/* For the moment there is a bug with XP that don't seems to appriciate much
+		 * level4 so we return just level 3 for everyone
+		 */
+		ref->referral.v4.server_type = DFS_SERVER_NON_ROOT;
+		/* "normal" referral seems to always include the GUID */
+		ref->referral.v4.size = 34;
+
+		if (isfirstoffset) {
+			ref->referral.v4.entry_flags =  DFS_HEADER_FLAG_TARGET_BCK;
+		}
+		ref->referral.v4.ttl = 900; /* As w2k8r2 */
+		ref->referral.v4.referrals.r1.DFS_path = talloc_strdup(mem_ctx, dfs_path);
+		if (ref->referral.v4.referrals.r1.DFS_path == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ref->referral.v4.referrals.r1.DFS_alt_path = talloc_strdup(mem_ctx, dfs_path);
+		if (ref->referral.v4.referrals.r1.DFS_alt_path == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ref->referral.v4.referrals.r1.netw_address = talloc_strdup(mem_ctx, server_path);
+		if (ref->referral.v4.referrals.r1.netw_address == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		return NT_STATUS_OK;
+#endif
+	case 3:
+		ref->version = version;
+		ref->referral.v3.server_type = DFS_SERVER_NON_ROOT;
+		/* "normal" referral seems to always include the GUID */
+		ref->referral.v3.size = 34;
+
+		ref->referral.v3.entry_flags = 0;
+		ref->referral.v3.ttl = 600; /* As w2k3 */
+		ref->referral.v3.referrals.r1.DFS_path = talloc_strdup(mem_ctx, dfs_path);
+		if (ref->referral.v3.referrals.r1.DFS_path == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ref->referral.v3.referrals.r1.DFS_alt_path = talloc_strdup(mem_ctx, dfs_path);
+		if (ref->referral.v3.referrals.r1.DFS_alt_path == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ref->referral.v3.referrals.r1.netw_address = talloc_strdup(mem_ctx, server_path);
+		if (ref->referral.v3.referrals.r1.netw_address == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		return NT_STATUS_OK;
+	}
+	return NT_STATUS_INVALID_LEVEL;
+}
+
+/*
+  fill a domain refererral
+ */
+static NTSTATUS fill_domain_dfs_referraltype(TALLOC_CTX *mem_ctx,
+					     struct dfs_referral_type *ref,
+					     uint16_t version,
+					     const char *domain,
+					     const char **names,
+					     uint16_t numnames)
+{
+	switch (version) {
+	case 3:
+		ZERO_STRUCTP(ref);
+		DEBUG(8, ("Called fill_domain_dfs_referraltype\n"));
+		ref->version = version;
+		ref->referral.v3.server_type = DFS_SERVER_NON_ROOT;
+		/*
+		 * It's hard coded ... don't think it's a good way but the
+		 * sizeof return not the correct values
+		 *
+		 * We have 18 if the GUID is not included 34 otherwise
+		 */
+		if (numnames == 0) {
+			/* Windows return without the guid when returning domain list
+			 */
+			ref->referral.v3.size = 18;
+		} else {
+			ref->referral.v3.size = 34;
+		}
+		ref->referral.v3.entry_flags = DFS_FLAG_REFERRAL_DOMAIN_RESP;
+		ref->referral.v3.ttl = 600; /* As w2k3 */
+		ref->referral.v3.referrals.r2.special_name = talloc_strdup(mem_ctx,
+									domain);
+		if (ref->referral.v3.referrals.r2.special_name == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+		ref->referral.v3.referrals.r2.nb_expanded_names = numnames;
+		/* Put the final terminator */
+		if (names) {
+			int i;
+			const char **names2 = talloc_array(mem_ctx, const char *,
+							   numnames+1);
+			NT_STATUS_HAVE_NO_MEMORY(names2);
+			for (i = 0; i<numnames; i++) {
+				names2[i] = talloc_asprintf(names2, "\\%s", names[i]);
+				NT_STATUS_HAVE_NO_MEMORY(names2[i]);
+			}
+			names2[numnames] = NULL;
+			ref->referral.v3.referrals.r2.expanded_names = names2;
+		}
+		return NT_STATUS_OK;
+	}
+	return NT_STATUS_INVALID_LEVEL;
+}
+
+/*
+  get the DCs list within a site
+ */
+static NTSTATUS get_dcs_insite(TALLOC_CTX *ctx, struct ldb_context *ldb,
+			       struct ldb_dn *sitedn, struct dc_set *list,
+			       bool dofqdn)
+{
+	static const char *attrs[] = { "serverReference", NULL };
+	static const char *attrs2[] = { "dNSHostName", "sAMAccountName", NULL };
+	struct ldb_result *r;
+	unsigned int i;
+	int ret;
+	const char **dc_list;
+
+	ret = ldb_search(ldb, ctx, &r, sitedn, LDB_SCOPE_SUBTREE, attrs,
+			 "(&(objectClass=server)(serverReference=*))");
+	if (ret != LDB_SUCCESS) {
+		DEBUG(2,(__location__ ": Failed to get list of servers - %s\n",
+			 ldb_errstring(ldb)));
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	if (r->count == 0) {
+		/* none in this site */
+		talloc_free(r);
+		return NT_STATUS_OK;
+	}
+
+	/*
+	 * need to search for all server object to know the size of the array.
+	 * Search all the object of class server in this site
+	 */
+	dc_list = talloc_array(r, const char *, r->count);
+	NT_STATUS_HAVE_NO_MEMORY_AND_FREE(dc_list, r);
+
+	/* TODO put some random here in the order */
+	list->names = talloc_realloc(list, list->names, const char *, list->count + r->count);
+	NT_STATUS_HAVE_NO_MEMORY_AND_FREE(list->names, r);
+
+	for (i = 0; i<r->count; i++) {
+		struct ldb_dn  *dn;
+		struct ldb_result *r2;
+
+		dn = ldb_msg_find_attr_as_dn(ldb, ctx, r->msgs[i], "serverReference");
+		if (!dn) {
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+
+		ret = ldb_search(ldb, r, &r2, dn, LDB_SCOPE_BASE, attrs2, "(objectClass=computer)");
+		if (ret != LDB_SUCCESS) {
+			DEBUG(2,(__location__ ": Search for computer on %s failed - %s\n",
+				 ldb_dn_get_linearized(dn), ldb_errstring(ldb)));
+			return NT_STATUS_INTERNAL_ERROR;
+		}
+
+		if (dofqdn) {
+			const char *dns = ldb_msg_find_attr_as_string(r2->msgs[0], "dNSHostName", NULL);
+			if (dns == NULL) {
+				DEBUG(2,(__location__ ": dNSHostName missing on %s\n",
+					 ldb_dn_get_linearized(dn)));
+				talloc_free(r);
+				return NT_STATUS_INTERNAL_ERROR;
+			}
+
+			list->names[list->count] = talloc_strdup(list->names, dns);
+			NT_STATUS_HAVE_NO_MEMORY_AND_FREE(list->names[list->count], r);
+		} else {
+			char *tmp;
+			const char *acct = ldb_msg_find_attr_as_string(r2->msgs[0], "sAMAccountName", NULL);
+			if (acct == NULL) {
+				DEBUG(2,(__location__ ": sAMAccountName missing on %s\n",
+					 ldb_dn_get_linearized(dn)));
+				talloc_free(r);
+				return NT_STATUS_INTERNAL_ERROR;
+			}
+
+			tmp = talloc_strdup(list->names, acct);
+			NT_STATUS_HAVE_NO_MEMORY_AND_FREE(tmp, r);
+
+			/* Netbios name is also the sAMAccountName for
+			   computer but without the final $ */
+			tmp[strlen(tmp) - 1] = '\0';
+			list->names[list->count] = tmp;
+		}
+		list->count++;
+		talloc_free(r2);
+	}
+
+	talloc_free(r);
+	return NT_STATUS_OK;
+}
+
+
+/*
+  get all DCs
+ */
+static NTSTATUS get_dcs(TALLOC_CTX *ctx, struct ldb_context *ldb,
+			const char *searched_site, bool need_fqdn,
+			struct dc_set ***pset_list, uint32_t flags)
+{
+	/*
+	 * Flags will be used later to indicate things like least-expensive
+	 * or same-site options
+	 */
+	const char *attrs_none[] = { NULL };
+	const char *attrs3[] = { "name", NULL };
+	struct ldb_dn *configdn, *sitedn, *dn, *sitescontainerdn;
+	struct ldb_result *r;
+	struct dc_set **set_list = NULL;
+	uint32_t i;
+	int ret;
+	uint32_t current_pos = 0;
+	NTSTATUS status;
+	TALLOC_CTX *subctx = talloc_new(ctx);
+
+	*pset_list = set_list = NULL;
+
+	subctx = talloc_new(ctx);
+	NT_STATUS_HAVE_NO_MEMORY(subctx);
+
+	configdn = ldb_get_config_basedn(ldb);
+
+	/* Let's search for the Site container */
+	ret = ldb_search(ldb, subctx, &r, configdn, LDB_SCOPE_SUBTREE, attrs_none,
+			 "(objectClass=sitesContainer)");
+	if (ret != LDB_SUCCESS) {
+		DEBUG(2,(__location__ ": Failed to find sitesContainer within %s - %s\n",
+			 ldb_dn_get_linearized(configdn), ldb_errstring(ldb)));
+		talloc_free(subctx);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	if (r->count > 1) {
+		DEBUG(2,(__location__ ": Expected 1 sitesContainer - found %u within %s\n",
+			 r->count, ldb_dn_get_linearized(configdn)));
+		talloc_free(subctx);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+
+	sitescontainerdn = talloc_steal(subctx, r->msgs[0]->dn);
+	talloc_free(r);
+
+	/*
+	 * TODO: Here we should have a more subtle handling
+	 * for the case "same-site"
+	 */
+	ret = ldb_search(ldb, subctx, &r, sitescontainerdn, LDB_SCOPE_SUBTREE,
+			 attrs_none, "(objectClass=server)");
+	if (ret != LDB_SUCCESS) {
+		DEBUG(2,(__location__ ": Failed to find servers within %s - %s\n",
+			 ldb_dn_get_linearized(sitescontainerdn), ldb_errstring(ldb)));
+		talloc_free(subctx);
+		return NT_STATUS_INTERNAL_ERROR;
+	}
+	talloc_free(r);
+
+	if (searched_site != NULL && searched_site[0] != '\0') {
+		ret = ldb_search(ldb, subctx, &r, configdn, LDB_SCOPE_SUBTREE,
+				 attrs_none, "(&(name=%s)(objectClass=site))", searched_site);
+		if (ret != LDB_SUCCESS) {
+			talloc_free(subctx);
+			return NT_STATUS_FOOBAR;
+		} else if (r->count != 1) {
+			talloc_free(subctx);
+			return NT_STATUS_FOOBAR;
+		}
+
+		/* All of this was to get the DN of the searched_site */
+		sitedn = r->msgs[0]->dn;
+
+		set_list = talloc_realloc(subctx, set_list, struct dc_set *, current_pos+1);
+		NT_STATUS_HAVE_NO_MEMORY_AND_FREE(set_list, subctx);
+
+		set_list[current_pos] = talloc(set_list, struct dc_set);
+		NT_STATUS_HAVE_NO_MEMORY_AND_FREE(set_list[current_pos], subctx);
+
+		set_list[current_pos]->names = NULL;
+		set_list[current_pos]->count = 0;
+		status = get_dcs_insite(subctx, ldb, sitedn,
+					set_list[current_pos], need_fqdn);
+		if (!NT_STATUS_IS_OK(status)) {
+			DEBUG(2,(__location__ ": Failed to get DC from site %s - %s\n",
+				 ldb_dn_get_linearized(sitedn), nt_errstr(status)));
+			talloc_free(subctx);
+			return status;
+		}
+		talloc_free(r);
+		current_pos++;
+	}
+
+	/* Let's find all the sites */
+	ret = ldb_search(ldb, subctx, &r, configdn, LDB_SCOPE_SUBTREE, attrs3, "(objectClass=site)");
+	if (ret != LDB_SUCCESS) {
+		DEBUG(2,(__location__ ": Failed to find any site containers in %s\n",
+			 ldb_dn_get_linearized(configdn)));
+		talloc_free(subctx);
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	/*
+	 * TODO:
+	 * We should randomize the order in the main site,
+	 * it's mostly needed for sysvol/netlogon referral.
+	 * Depending of flag we either randomize order of the
+	 * not "in the same site DCs"
+	 * or we randomize by group of site that have the same cost
+	 * In the long run we want to manipulate an array of site_set
+	 * All the site in one set have the same cost (if least-expansive options is selected)
+	 * and we will put all the dc related to 1 site set into 1 DCs set.
+	 * Within a site set, site order has to be randomized
+	 *
+	 * But for the moment we just return the list of sites
+	 */
+	if (r->count) {
+		/*
+		 * We will realloc + 2 because we will need one additional place
+		 * for element at current_pos + 1 for the NULL element
+		 */
+		set_list = talloc_realloc(subctx, set_list, struct dc_set *,
+					  current_pos+2);
+		NT_STATUS_HAVE_NO_MEMORY_AND_FREE(set_list, subctx);
+
+		set_list[current_pos] = talloc(ctx, struct dc_set);
+		NT_STATUS_HAVE_NO_MEMORY_AND_FREE(set_list[current_pos], subctx);
+
+		set_list[current_pos]->names = NULL;
+		set_list[current_pos]->count = 0;
+
+		set_list[current_pos+1] = NULL;
+	}
+
+	for (i=0; i<r->count; i++) {
+		const char *site_name = ldb_msg_find_attr_as_string(r->msgs[i], "name", NULL);
+		if (site_name == NULL) {
+			DEBUG(2,(__location__ ": Failed to find name attribute in %s\n",
+				 ldb_dn_get_linearized(r->msgs[i]->dn)));
+			talloc_free(subctx);
+			return NT_STATUS_INTERNAL_DB_CORRUPTION;
+		}
+
+		if (searched_site == NULL ||
+		    strcmp(searched_site, site_name) != 0) {
+			DEBUG(2,(__location__ ": Site: %s %s\n",
+				searched_site, site_name));
+
+			/*
+			 * Do all the site but the one of the client
+			 * (because it has already been done ...)
+			 */
+			dn = r->msgs[i]->dn;
+
+			status = get_dcs_insite(subctx, ldb, dn,
+						set_list[current_pos],
+						need_fqdn);
+			if (!NT_STATUS_IS_OK(status)) {
+				talloc_free(subctx);
+				return status;
+			}
+		}
+	}
+	current_pos++;
+	set_list[current_pos] = NULL;
+
+	*pset_list = talloc_move(ctx, &set_list);
+	talloc_free(subctx);
+	return NT_STATUS_OK;
+}
+
+static NTSTATUS dodomain_referral(struct loadparm_context *lp_ctx,
+				  struct ldb_context *sam_ctx,
+				  const struct tsocket_address *client,
+				  struct dfs_GetDFSReferral *r)
+{
+	/*
+	 * TODO for the moment we just return the local domain
+	 */
+	NTSTATUS status;
+	const char *dns_domain = lpcfg_dnsdomain(lp_ctx);
+	const char *netbios_domain = lpcfg_workgroup(lp_ctx);
+	struct dfs_referral_type *referrals;
+	const char *referral_str;
+	/* In the future this needs to be fetched from the ldb */
+	uint32_t found_domain = 2;
+
+	if (lpcfg_server_role(lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
+		DEBUG(10 ,("Received a domain referral request on a non DC\n"));
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (r->in.req.max_referral_level < 3) {
+		DEBUG(2,("invalid max_referral_level %u\n",
+			 r->in.req.max_referral_level));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	r->out.resp = talloc_zero(r, struct dfs_referral_resp);
+	if (r->out.resp == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	r->out.resp->path_consumed = 0;
+	r->out.resp->header_flags = 0; /* Do like w2k3 */
+	r->out.resp->nb_referrals = found_domain; /* the fqdn one + the NT domain */
+
+	referrals = talloc_zero_array(r->out.resp,
+				      struct dfs_referral_type,
+				      r->out.resp->nb_referrals);
+	if (referrals == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	r->out.resp->referral_entries = referrals;
+
+	referral_str = talloc_asprintf(r, "\\%s", netbios_domain);
+	if (referral_str == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	status = fill_domain_dfs_referraltype(referrals,
+					      &referrals[0], 3,
+					      referral_str,
+					      NULL, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(2,("%s: Unable to fill domain referral structure - %s\n",
+			 __location__, nt_errstr(status)));
+		return status;
+	}
+
+	referral_str = talloc_asprintf(r, "\\%s", dns_domain);
+	if (referral_str == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	status = fill_domain_dfs_referraltype(referrals,
+					      &referrals[1], 3,
+					      referral_str,
+					      NULL, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(2,("%s: Unable to fill domain referral structure - %s\n",
+			 __location__, nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+ * Handle the logic for dfs referral request like
+ * \\dns_domain or \\netbios_domain.
+ */
+static NTSTATUS dodc_referral(struct loadparm_context *lp_ctx,
+			      struct ldb_context *sam_ctx,
+			      const struct tsocket_address *client,
+			      struct dfs_GetDFSReferral *r,
+			      const char *domain_name)
+{
+	NTSTATUS status;
+	const char *site_name = NULL; /* Name of the site where the client is */
+	bool need_fqdn = false;
+	unsigned int i;
+	const char **dc_list = NULL;
+	uint32_t num_dcs = 0;
+	struct dc_set **set;
+	char *client_str = NULL;
+	struct dfs_referral_type *referrals;
+	const char *referral_str;
+
+	if (lpcfg_server_role(lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (r->in.req.max_referral_level < 3) {
+		DEBUG(2,("invalid max_referral_level %u\n",
+			 r->in.req.max_referral_level));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	DEBUG(10, ("in this we have request for %s requested is %s\n",
+		   domain_name, r->in.req.servername));
+
+	if (strchr(domain_name,'.')) {
+		need_fqdn = 1;
+	}
+
+	if (tsocket_address_is_inet(client, "ip")) {
+		client_str = tsocket_address_inet_addr_string(client, r);
+		if (client_str == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+	}
+
+	site_name = samdb_client_site_name(sam_ctx, r, client_str, NULL);
+
+	status = get_dcs(r, sam_ctx, site_name, need_fqdn, &set, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(3,("Unable to get list of DCs - %s\n",
+			 nt_errstr(status)));
+		return status;
+	}
+
+	for(i=0; set[i]; i++) {
+		uint32_t j;
+
+		dc_list = talloc_realloc(r, dc_list, const char*,
+					 num_dcs + set[i]->count + 1);
+		if (dc_list == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+
+		for(j=0; j<set[i]->count; j++) {
+			dc_list[num_dcs + j] = talloc_move(dc_list,
+							   &set[i]->names[j]);
+		}
+		num_dcs = num_dcs + set[i]->count;
+		TALLOC_FREE(set[i]);
+		dc_list[num_dcs] = NULL;
+	}
+
+	r->out.resp = talloc_zero(r, struct dfs_referral_resp);
+	if (r->out.resp == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	r->out.resp->path_consumed = 0;
+	r->out.resp->header_flags = 0; /* Do like w2k3 */
+	r->out.resp->nb_referrals = 1;
+
+	referrals = talloc_zero_array(r->out.resp,
+				      struct dfs_referral_type,
+				      r->out.resp->nb_referrals);
+	if (referrals == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	r->out.resp->referral_entries = referrals;
+
+	if (r->in.req.servername[0] == '\\') {
+		referral_str = talloc_asprintf(referrals, "%s",
+					       domain_name);
+	} else {
+		referral_str = talloc_asprintf(referrals, "\\%s",
+					       domain_name);
+	}
+	if (referral_str == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	status = fill_domain_dfs_referraltype(referrals,
+					      &referrals[0], 3,
+					      referral_str,
+					      dc_list, num_dcs);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(2,("%s: Unable to fill domain referral structure - %s\n",
+			 __location__, nt_errstr(status)));
+		return status;
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+ * Handle the logic for dfs referral request like
+ * \\domain\sysvol or \\domain\netlogon
+ */
+static NTSTATUS dosysvol_referral(struct loadparm_context *lp_ctx,
+				  struct ldb_context *sam_ctx,
+				  const struct tsocket_address *client,
+				  struct dfs_GetDFSReferral *r,
+				  const char *domain_name,
+				  const char *dfs_name)
+{
+	const char *site_name = NULL; /* Name of the site where the client is */
+	bool need_fqdn = false;
+	unsigned int i, c = 0, nb_entries = 0;
+	struct dc_set **set;
+	char *client_str = NULL;
+	NTSTATUS status;
+	struct dfs_referral_type *referrals;
+
+	if (lpcfg_server_role(lp_ctx) != ROLE_DOMAIN_CONTROLLER) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (r->in.req.max_referral_level < 3) {
+		DEBUG(2,("invalid max_referral_level %u\n",
+			 r->in.req.max_referral_level));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	DEBUG(10, ("in this we have request for %s and share %s requested is %s\n",
+		   domain_name, dfs_name, r->in.req.servername));
+
+	if (strchr(domain_name,'.')) {
+		need_fqdn = 1;
+	}
+
+	if (tsocket_address_is_inet(client, "ip")) {
+		client_str = tsocket_address_inet_addr_string(client, r);
+		if (client_str == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+	}
+
+	site_name = samdb_client_site_name(sam_ctx, r, client_str, NULL);
+
+	status = get_dcs(r, sam_ctx, site_name, need_fqdn, &set, 0);
+	if (!NT_STATUS_IS_OK(status)) {
+		DEBUG(3,("Unable to get list of DCs - %s\n",
+			 nt_errstr(status)));
+		return status;
+	}
+
+	for(i=0; set[i]; i++) {
+		nb_entries = nb_entries + set[i]->count;
+	}
+
+	r->out.resp = talloc_zero(r, struct dfs_referral_resp);
+	if (r->out.resp == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	/* The length is expected in bytes */
+	r->out.resp->path_consumed = strlen_m(r->in.req.servername) * 2;
+	/* Do like w2k3 and like in 3.3.5.3 of MS-DFSC*/
+	r->out.resp->header_flags = DFS_HEADER_FLAG_STORAGE_SVR;
+	r->out.resp->nb_referrals = nb_entries;
+
+	referrals = talloc_zero_array(r->out.resp,
+				      struct dfs_referral_type,
+				      r->out.resp->nb_referrals);
+	if (referrals == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	r->out.resp->referral_entries = referrals;
+
+	c = 0;
+	for(i=0; set[i]; i++) {
+		uint32_t j;
+
+		for(j=0; j< set[i]->count; j++) {
+			struct dfs_referral_type *ref = &referrals[c];
+			const char *referral_str;
+
+			referral_str = talloc_asprintf(referrals, "\\%s\\%s",
+						       set[i]->names[j], dfs_name);
+			if (referral_str == NULL) {
+				return NT_STATUS_NO_MEMORY;
+			}
+
+			DEBUG(8,("Doing a dfs referral for %s with this value "
+				 "%s requested %s\n",
+				 set[i]->names[j], referral_str,
+				 r->in.req.servername));
+
+			status = fill_normal_dfs_referraltype(referrals, ref,
+					r->in.req.max_referral_level,
+					r->in.req.servername,
+					referral_str, c==0);
+
+
+			if (!NT_STATUS_IS_OK(status)) {
+				DEBUG(2,("%s: Unable to fill domain referral "
+					 "structure - %s\n",
+					 __location__, nt_errstr(status)));
+				return status;
+			}
+
+			c++;
+		}
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+  trans2 getdfsreferral implementation
+*/
+NTSTATUS dfs_server_ad_get_referrals(struct loadparm_context *lp_ctx,
+				     struct ldb_context *sam_ctx,
+				     const struct tsocket_address *client,
+				     struct dfs_GetDFSReferral *r)
+{
+	char *server_name = NULL;
+	char *dfs_name = NULL;
+	char *link_path = NULL;
+	const char *netbios_domain;
+	const char *dns_domain;
+	const char *netbios_name;
+	const char *dns_name;
+
+	if (!lpcfg_host_msdfs(lp_ctx)) {
+		return NT_STATUS_FS_DRIVER_REQUIRED;
+	}
+
+	if (r->in.req.servername == NULL) {
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	DEBUG(8, ("Requested DFS name: %s length: %u\n",
+		  r->in.req.servername,
+		  (unsigned int)strlen_m(r->in.req.servername)*2));
+
+	/*
+	 * If the servername is "" then we are in a case of domain dfs
+	 * and the client just searches for the list of local domain
+	 * it is attached and also trusted ones.
+	 */
+	if (strlen(r->in.req.servername) == 0) {
+		return dodomain_referral(lp_ctx, sam_ctx, client, r);
+	}
+
+	server_name = talloc_strdup(r, r->in.req.servername);
+	if (server_name == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	while(*server_name && *server_name == '\\') {
+		server_name++;
+	}
+
+	dfs_name = strchr(server_name, '\\');
+	if (dfs_name != NULL) {
+		dfs_name[0] = '\0';
+		dfs_name++;
+
+		link_path = strchr(dfs_name, '\\');
+		if (link_path != NULL) {
+			link_path[0] = '\0';
+			link_path++;
+		}
+	}
+
+	if (link_path != NULL) {
+		/*
+		 * If it is a DFS Link we do not
+		 * handle it here.
+		 */
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	netbios_domain = lpcfg_workgroup(lp_ctx);
+	dns_domain = lpcfg_dnsdomain(lp_ctx);
+	netbios_name = lpcfg_netbios_name(lp_ctx);
+	dns_name = talloc_asprintf(r, "%s.%s", netbios_name, dns_domain);
+	if (dns_name == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if ((strcasecmp_m(server_name, netbios_name) == 0) ||
+	    (strcasecmp_m(server_name, dns_name) == 0)) {
+		/*
+		 * If it is not domain related do not
+		 * handle it here.
+		 */
+		return NT_STATUS_NOT_FOUND;
+
+	}
+
+	if ((strcasecmp_m(server_name, netbios_domain) != 0) &&
+	    (strcasecmp_m(server_name, dns_domain) != 0)) {
+		/*
+		 * Not a domain we handle.
+		 */
+		return NT_STATUS_INVALID_PARAMETER;
+	}
+
+	/*
+	 * Here we have filtered the thing the requested name don't contain our DNS name.
+	 * So if the share == NULL or if share in ("sysvol", "netlogon")
+	 * then we proceed. In the first case it will be a dc refereal in the second it will
+	 * be just a sysvol/netlogon referral.
+	 */
+	if (dfs_name == NULL) {
+		return dodc_referral(lp_ctx, sam_ctx,
+				     client, r, server_name);
+	}
+
+	/*
+	 * Here we have filtered the thing the requested name don't contain our DNS name.
+	 * So if the share == NULL or if share in ("sysvol", "netlogon")
+	 * then we proceed. In the first case it will be a dc refereal in the second it will
+	 * be just a sysvol/netlogon referral.
+	 */
+	if (strcasecmp(dfs_name, "sysvol") == 0 ||
+	    strcasecmp(dfs_name, "netlogon") == 0) {
+		return dosysvol_referral(lp_ctx, sam_ctx, client, r,
+					 server_name, dfs_name);
+	}
+
+	/* By default until all the case are handled */
+	return NT_STATUS_NOT_FOUND;
+}
diff --git a/dfs_server/dfs_server_ad.h b/dfs_server/dfs_server_ad.h
new file mode 100644
index 00000000000..cda923d639c
--- /dev/null
+++ b/dfs_server/dfs_server_ad.h
@@ -0,0 +1,23 @@
+/*
+   Unix SMB/CIFS implementation.
+
+   Copyright Stefan Metzmacher 2011
+
+   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/>.
+*/
+
+NTSTATUS dfs_server_ad_get_referrals(struct loadparm_context *lp_ctx,
+				     struct ldb_context *sam_ctx,
+				     const struct tsocket_address *client,
+				     struct dfs_GetDFSReferral *r);
diff --git a/dfs_server/wscript_build b/dfs_server/wscript_build
new file mode 100644
index 00000000000..294eccf3fe3
--- /dev/null
+++ b/dfs_server/wscript_build
@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+
+bld.SAMBA_LIBRARY('dfs_server_ad',
+                  source='dfs_server_ad.c',
+                  deps='talloc samdb samba-util LIBTSOCKET',
+                  private_library=True
+                  )
diff --git a/wscript_build b/wscript_build
index 936aa53eb45..25d8eff5846 100644
--- a/wscript_build
+++ b/wscript_build
@@ -117,6 +117,7 @@ bld.RECURSE('pidl')
 bld.RECURSE('lib')
 bld.RECURSE('libds/common')
 bld.RECURSE('source3')
+bld.RECURSE('dfs_server')
 
 bld.RECURSE('testsuite/headers')