/*
 * Unix SMB/CIFS implementation.
 * async xids2sids
 * Copyright (C) Volker Lendecke 2015
 *
 * 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 "winbindd.h"
#include "../libcli/security/security.h"
#include "idmap_cache.h"
#include "librpc/gen_ndr/ndr_winbind_c.h"
#include "librpc/gen_ndr/ndr_netlogon.h"

struct wb_xids2sids_dom_map {
	unsigned low_id;
	unsigned high_id;
	const char *name;
};

/*
 * Map idmap ranges to domain names, taken from smb.conf. This is
 * stored in the parent winbind and used to assemble xid2sid calls
 * into per-idmap-domain chunks.
 */
static struct wb_xids2sids_dom_map *dom_maps;

static bool wb_xids2sids_add_dom(const char *domname,
				 void *private_data)
{
	struct wb_xids2sids_dom_map *map = NULL;
	size_t num_maps = talloc_array_length(dom_maps);
	size_t i;
	char *config_option;
	const char *range;
	unsigned low_id, high_id;
	int ret;

	config_option = talloc_asprintf(
		talloc_tos(), "idmap config %s", domname);
	if (config_option == NULL) {
		return false;
	}
	range = lp_parm_const_string(-1, config_option, "range", NULL);
	TALLOC_FREE(config_option);

	if (range == NULL) {
		DBG_DEBUG("No range for domain %s found\n", domname);
		return false;
	}

	ret = sscanf(range, "%u - %u", &low_id, &high_id);
	if (ret != 2) {
		DBG_DEBUG("Invalid range spec \"%s\" for domain %s\n",
			  range, domname);
		return false;
	}

	if (low_id > high_id) {
		DBG_DEBUG("Invalid range %u - %u for domain %s\n",
			  low_id, high_id, domname);
		return false;
	}

	for (i=0; i<num_maps; i++) {
		if (strequal(domname, dom_maps[i].name)) {
			map = &dom_maps[i];
			break;
		}
	}

	if (map == NULL) {
		struct wb_xids2sids_dom_map *tmp;
		char *name;

		name = talloc_strdup(talloc_tos(), domname);
		if (name == NULL) {
			DBG_DEBUG("talloc failed\n");
			return false;
		}

		tmp = talloc_realloc(
			NULL, dom_maps, struct wb_xids2sids_dom_map,
			num_maps+1);
		if (tmp == NULL) {
			TALLOC_FREE(name);
			return false;
		}
		dom_maps = tmp;

		map = &dom_maps[num_maps];
		map->name = talloc_move(dom_maps, &name);
	}

	map->low_id = low_id;
	map->high_id = high_id;

	return false;
}

static void wb_xids2sids_init_dom_maps(void)
{
	if (dom_maps != NULL) {
		return;
	}

	/*
	 * Put the passdb idmap domain first. We always need to try
	 * there first.
	 */

	dom_maps = talloc_array(NULL, struct wb_xids2sids_dom_map, 1);
	if (dom_maps == NULL) {
		return;
	}
	dom_maps[0].low_id = 0;
	dom_maps[0].high_id = UINT_MAX;
	dom_maps[0].name = talloc_strdup(dom_maps, get_global_sam_name());
	if (dom_maps[0].name == NULL) {
		TALLOC_FREE(dom_maps);
		return;
	}

	lp_scan_idmap_domains(wb_xids2sids_add_dom, NULL);
}

struct wb_xids2sids_dom_state {
	struct tevent_context *ev;
	struct unixid *all_xids;
	size_t num_all_xids;
	struct dom_sid *all_sids;
	struct wb_xids2sids_dom_map *dom_map;
	bool tried_dclookup;

	size_t num_dom_xids;
	struct unixid *dom_xids;
	struct dom_sid *dom_sids;
};

static void wb_xids2sids_dom_done(struct tevent_req *subreq);
static void wb_xids2sids_dom_gotdc(struct tevent_req *subreq);

static struct tevent_req *wb_xids2sids_dom_send(
	TALLOC_CTX *mem_ctx, struct tevent_context *ev,
	struct wb_xids2sids_dom_map *dom_map,
	struct unixid *xids, size_t num_xids, struct dom_sid *sids)
{
	struct tevent_req *req, *subreq;
	struct wb_xids2sids_dom_state *state;
	struct winbindd_child *child;
	size_t i;

	req = tevent_req_create(mem_ctx, &state,
				struct wb_xids2sids_dom_state);
	if (req == NULL) {
		return NULL;
	}
	state->ev = ev;
	state->all_xids = xids;
	state->num_all_xids = num_xids;
	state->all_sids = sids;
	state->dom_map = dom_map;

	state->dom_xids = talloc_array(state, struct unixid, num_xids);
	if (tevent_req_nomem(state->dom_xids, req)) {
		return tevent_req_post(req, ev);
	}
	state->dom_sids = talloc_array(state, struct dom_sid, num_xids);
	if (tevent_req_nomem(state->dom_sids, req)) {
		return tevent_req_post(req, ev);
	}

	for (i=0; i<num_xids; i++) {
		struct unixid id = state->all_xids[i];

		if ((id.id < dom_map->low_id) || (id.id > dom_map->high_id)) {
			/* out of range */
			continue;
		}
		if (!is_null_sid(&state->all_sids[i])) {
			/* already mapped */
			continue;
		}

		state->dom_xids[state->num_dom_xids++] = id;
	}

	if (state->num_dom_xids == 0) {
		tevent_req_done(req);
		return tevent_req_post(req, ev);
	}

	child = idmap_child();
	subreq = dcerpc_wbint_UnixIDs2Sids_send(
		state, ev, child->binding_handle, dom_map->name,
		state->num_dom_xids, state->dom_xids, state->dom_sids);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, wb_xids2sids_dom_done, req);
	return req;
}

static void wb_xids2sids_dom_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct wb_xids2sids_dom_state *state = tevent_req_data(
		req, struct wb_xids2sids_dom_state);
	struct wb_xids2sids_dom_map *dom_map = state->dom_map;
	NTSTATUS status, result;
	size_t i;
	size_t dom_sid_idx;

	status = dcerpc_wbint_UnixIDs2Sids_recv(subreq, state, &result);
	TALLOC_FREE(subreq);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	if (NT_STATUS_EQUAL(result, NT_STATUS_DOMAIN_CONTROLLER_NOT_FOUND) &&
	    !state->tried_dclookup) {

		subreq = wb_dsgetdcname_send(
			state, state->ev, state->dom_map->name, NULL, NULL,
			DS_RETURN_DNS_NAME);
		if (tevent_req_nomem(subreq, req)) {
			return;
		}
		tevent_req_set_callback(subreq, wb_xids2sids_dom_gotdc, req);
		return;
	}

	if (!NT_STATUS_EQUAL(result, NT_STATUS_NONE_MAPPED) &&
	    tevent_req_nterror(req, result)) {
		return;
	}

	dom_sid_idx = 0;

	for (i=0; i<state->num_all_xids; i++) {
		struct unixid id = state->all_xids[i];

		if ((id.id < dom_map->low_id) || (id.id > dom_map->high_id)) {
			/* out of range */
			continue;
		}
		if (!is_null_sid(&state->all_sids[i])) {
			/* already mapped */
			continue;
		}

		sid_copy(&state->all_sids[i], &state->dom_sids[dom_sid_idx++]);
	}

	tevent_req_done(req);
}

static void wb_xids2sids_dom_gotdc(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct wb_xids2sids_dom_state *state = tevent_req_data(
		req, struct wb_xids2sids_dom_state);
	struct winbindd_child *child = idmap_child();
	struct netr_DsRGetDCNameInfo *dcinfo;
	NTSTATUS status;

	status = wb_dsgetdcname_recv(subreq, state, &dcinfo);
	TALLOC_FREE(subreq);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	state->tried_dclookup = true;

	status = wb_dsgetdcname_gencache_set(state->dom_map->name, dcinfo);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	child = idmap_child();
	subreq = dcerpc_wbint_UnixIDs2Sids_send(
		state, state->ev, child->binding_handle, state->dom_map->name,
		state->num_dom_xids, state->dom_xids, state->dom_sids);
	if (tevent_req_nomem(subreq, req)) {
		return;
	}
	tevent_req_set_callback(subreq, wb_xids2sids_dom_done, req);
}

static NTSTATUS wb_xids2sids_dom_recv(struct tevent_req *req)
{
	return tevent_req_simple_recv_ntstatus(req);
}

struct wb_xids2sids_state {
	struct tevent_context *ev;
	struct unixid *xids;
	size_t num_xids;
	struct dom_sid *sids;

	size_t dom_idx;
};

static void wb_xids2sids_done(struct tevent_req *subreq);

struct tevent_req *wb_xids2sids_send(TALLOC_CTX *mem_ctx,
				     struct tevent_context *ev,
				     struct unixid *xids,
				     uint32_t num_xids)
{
	struct tevent_req *req, *subreq;
	struct wb_xids2sids_state *state;
	size_t num_domains;

	req = tevent_req_create(mem_ctx, &state,
				struct wb_xids2sids_state);
	if (req == NULL) {
		return NULL;
	}
	state->ev = ev;
	state->xids = xids;
	state->num_xids = num_xids;

	state->sids = talloc_zero_array(state, struct dom_sid, num_xids);
	if (tevent_req_nomem(state->sids, req)) {
		return tevent_req_post(req, ev);
	}

	wb_xids2sids_init_dom_maps();
	num_domains = talloc_array_length(dom_maps);

	if (num_domains == 0) {
		tevent_req_done(req);
		return tevent_req_post(req, ev);
	}

	subreq = wb_xids2sids_dom_send(
		state, state->ev, &dom_maps[state->dom_idx],
		state->xids, state->num_xids, state->sids);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, wb_xids2sids_done, req);
	return req;
}

static void wb_xids2sids_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct wb_xids2sids_state *state = tevent_req_data(
		req, struct wb_xids2sids_state);
	size_t num_domains = talloc_array_length(dom_maps);
	NTSTATUS status;

	status = wb_xids2sids_dom_recv(subreq);
	TALLOC_FREE(subreq);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	state->dom_idx += 1;

	if (state->dom_idx >= num_domains) {
		tevent_req_done(req);
		return;
	}

	subreq = wb_xids2sids_dom_send(
		state, state->ev, &dom_maps[state->dom_idx],
		state->xids, state->num_xids, state->sids);
	if (tevent_req_nomem(subreq, req)) {
		return;
	}
	tevent_req_set_callback(subreq, wb_xids2sids_done, req);
}

NTSTATUS wb_xids2sids_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
			   struct dom_sid **sids)
{
	struct wb_xids2sids_state *state = tevent_req_data(
		req, struct wb_xids2sids_state);
	NTSTATUS status;

	if (tevent_req_is_nterror(req, &status)) {
		DEBUG(5, ("wb_sids_to_xids failed: %s\n", nt_errstr(status)));
		return status;
	}

	*sids = talloc_move(mem_ctx, &state->sids);
	return NT_STATUS_OK;
}