/*
   Unix SMB/CIFS implementation.

   Provide parent->child communication based on NDR marshalling

   Copyright (C) Volker Lendecke 2009

   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/>.
*/

/*
 * This file implements an RPC between winbind parent and child processes,
 * leveraging the autogenerated marshalling routines for MSRPC. This is not
 * MSRPC, as it does not go through the whole DCERPC fragmentation, we just
 * leverage much the same infrastructure we already have for it.
 */

#include "includes.h"
#include "winbindd/winbindd.h"
#include "winbindd/winbindd_proto.h"
#include "ntdomain.h"
#include "librpc/rpc/dcesrv_core.h"
#include "librpc/gen_ndr/ndr_winbind.h"
#include "rpc_server/rpc_config.h"
#include "rpc_server/rpc_server.h"
#include "rpc_dce.h"
#include "lib/tsocket/tsocket.h"

struct wbint_bh_state {
	struct winbindd_domain *domain; /* if valid also talloc (grant) parent */
	struct winbindd_child *child;
	const struct dcerpc_binding *binding;
};

static const struct dcerpc_binding *wbint_bh_get_binding(struct dcerpc_binding_handle *h)
{
	struct wbint_bh_state *hs = dcerpc_binding_handle_data(h,
				     struct wbint_bh_state);

	return hs->binding;
}

static bool wbint_bh_is_connected(struct dcerpc_binding_handle *h)
{
	struct wbint_bh_state *hs = dcerpc_binding_handle_data(h,
				     struct wbint_bh_state);

	if ((hs->domain == NULL) && (hs->child == NULL)) {
		return false;
	}

	return true;
}

static uint32_t wbint_bh_set_timeout(struct dcerpc_binding_handle *h,
				     uint32_t timeout)
{
	/* TODO: implement timeouts */
	return UINT32_MAX;
}

struct wbint_bh_raw_call_state {
	struct winbindd_domain_ref domain;
	uint32_t opnum;
	DATA_BLOB in_data;
	struct winbindd_request request;
	struct winbindd_response *response;
	DATA_BLOB out_data;
};

static void wbint_bh_raw_call_child_done(struct tevent_req *subreq);
static void wbint_bh_raw_call_domain_done(struct tevent_req *subreq);

static struct tevent_req *wbint_bh_raw_call_send(TALLOC_CTX *mem_ctx,
						  struct tevent_context *ev,
						  struct dcerpc_binding_handle *h,
						  const struct GUID *object,
						  uint32_t opnum,
						  uint32_t in_flags,
						  const uint8_t *in_data,
						  size_t in_length)
{
	struct wbint_bh_state *hs =
		dcerpc_binding_handle_data(h,
		struct wbint_bh_state);
	struct tevent_req *req;
	struct wbint_bh_raw_call_state *state;
	bool ok;
	struct tevent_req *subreq;

	req = tevent_req_create(mem_ctx, &state,
				struct wbint_bh_raw_call_state);
	if (req == NULL) {
		return NULL;
	}
	winbindd_domain_ref_set(&state->domain, hs->domain);
	state->opnum = opnum;
	state->in_data.data = discard_const_p(uint8_t, in_data);
	state->in_data.length = in_length;

	ok = wbint_bh_is_connected(h);
	if (!ok) {
		tevent_req_nterror(req, NT_STATUS_CONNECTION_DISCONNECTED);
		return tevent_req_post(req, ev);
	}

	if ((hs->domain != NULL)
	    && wcache_fetch_ndr(state, hs->domain, state->opnum,
				&state->in_data, &state->out_data)) {
		DBG_DEBUG("Got opnum %"PRIu32" for domain %s from cache\n",
			  state->opnum, hs->domain->name);
		tevent_req_done(req);
		return tevent_req_post(req, ev);
	}

	state->request.cmd = WINBINDD_DUAL_NDRCMD;
	state->request.data.ndrcmd = state->opnum;
	state->request.extra_data.data = (char *)state->in_data.data;
	state->request.extra_len = state->in_data.length;

	if (hs->child != NULL) {
		subreq = wb_child_request_send(state, ev, hs->child,
					       &state->request);
		if (tevent_req_nomem(subreq, req)) {
			return tevent_req_post(req, ev);
		}
		tevent_req_set_callback(
			subreq, wbint_bh_raw_call_child_done, req);
		return req;
	}

	subreq = wb_domain_request_send(state, ev, hs->domain,
					&state->request);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, wbint_bh_raw_call_domain_done, req);

	return req;
}

static void wbint_bh_raw_call_child_done(struct tevent_req *subreq)
{
	struct tevent_req *req =
		tevent_req_callback_data(subreq,
		struct tevent_req);
	struct wbint_bh_raw_call_state *state =
		tevent_req_data(req,
		struct wbint_bh_raw_call_state);
	int ret, err;

	ret = wb_child_request_recv(subreq, state, &state->response, &err);
	TALLOC_FREE(subreq);
	if (ret == -1) {
		NTSTATUS status = map_nt_error_from_unix(err);
		tevent_req_nterror(req, status);
		return;
	}

	state->out_data = data_blob_talloc(state,
		state->response->extra_data.data,
		state->response->length - sizeof(struct winbindd_response));
	if (state->response->extra_data.data && !state->out_data.data) {
		tevent_req_oom(req);
		return;
	}

	tevent_req_done(req);
}

static void wbint_bh_raw_call_domain_done(struct tevent_req *subreq)
{
	struct tevent_req *req =
		tevent_req_callback_data(subreq,
		struct tevent_req);
	struct wbint_bh_raw_call_state *state =
		tevent_req_data(req,
		struct wbint_bh_raw_call_state);
	int ret, err;
	struct winbindd_domain *domain = NULL;
	bool valid;

	ret = wb_domain_request_recv(subreq, state, &state->response, &err);
	TALLOC_FREE(subreq);
	if (ret == -1) {
		NTSTATUS status = map_nt_error_from_unix(err);
		tevent_req_nterror(req, status);
		return;
	}

	state->out_data = data_blob_talloc(state,
		state->response->extra_data.data,
		state->response->length - sizeof(struct winbindd_response));
	if (state->response->extra_data.data && !state->out_data.data) {
		tevent_req_oom(req);
		return;
	}

	valid = winbindd_domain_ref_get(&state->domain, &domain);
	if (!valid) {
		/*
		 * winbindd_domain_ref_get() already generated
		 * a debug message for the stale domain!
		 *
		 * Just don't fill the cache
		 */
	} else {
		wcache_store_ndr(domain, state->opnum,
				 &state->in_data, &state->out_data);
	}

	tevent_req_done(req);
}

static NTSTATUS wbint_bh_raw_call_recv(struct tevent_req *req,
					TALLOC_CTX *mem_ctx,
					uint8_t **out_data,
					size_t *out_length,
					uint32_t *out_flags)
{
	struct wbint_bh_raw_call_state *state =
		tevent_req_data(req,
		struct wbint_bh_raw_call_state);
	NTSTATUS status;

	if (tevent_req_is_nterror(req, &status)) {
		tevent_req_received(req);
		return status;
	}

	*out_data = talloc_move(mem_ctx, &state->out_data.data);
	*out_length = state->out_data.length;
	*out_flags = 0;
	tevent_req_received(req);
	return NT_STATUS_OK;
}

struct wbint_bh_disconnect_state {
	uint8_t _dummy;
};

static struct tevent_req *wbint_bh_disconnect_send(TALLOC_CTX *mem_ctx,
						struct tevent_context *ev,
						struct dcerpc_binding_handle *h)
{
	struct wbint_bh_state *hs = dcerpc_binding_handle_data(h,
				     struct wbint_bh_state);
	struct tevent_req *req;
	struct wbint_bh_disconnect_state *state;
	bool ok;

	req = tevent_req_create(mem_ctx, &state,
				struct wbint_bh_disconnect_state);
	if (req == NULL) {
		return NULL;
	}

	ok = wbint_bh_is_connected(h);
	if (!ok) {
		tevent_req_nterror(req, NT_STATUS_CONNECTION_DISCONNECTED);
		return tevent_req_post(req, ev);
	}

	/*
	 * TODO: do a real async disconnect ...
	 */
	hs->domain = NULL;
	hs->child = NULL;

	tevent_req_done(req);
	return tevent_req_post(req, ev);
}

static NTSTATUS wbint_bh_disconnect_recv(struct tevent_req *req)
{
	NTSTATUS status;

	if (tevent_req_is_nterror(req, &status)) {
		tevent_req_received(req);
		return status;
	}

	tevent_req_received(req);
	return NT_STATUS_OK;
}

static bool wbint_bh_ref_alloc(struct dcerpc_binding_handle *h)
{
	return true;
}

static void wbint_bh_do_ndr_print(struct dcerpc_binding_handle *h,
				  ndr_flags_type ndr_flags,
				  const void *_struct_ptr,
				  const struct ndr_interface_call *call)
{
	void *struct_ptr = discard_const(_struct_ptr);

	if (!CHECK_DEBUGLVLC(DBGC_RPC_PARSE, 10)) {
		return;
	}

	if (ndr_flags & NDR_IN) {
		ndr_print_function_debug(call->ndr_print,
					 call->name,
					 ndr_flags,
					 struct_ptr);
	}
	if (ndr_flags & NDR_OUT) {
		ndr_print_function_debug(call->ndr_print,
					 call->name,
					 ndr_flags,
					 struct_ptr);
	}
}

static const struct dcerpc_binding_handle_ops wbint_bh_ops = {
	.name			= "wbint",
	.get_binding		= wbint_bh_get_binding,
	.is_connected		= wbint_bh_is_connected,
	.set_timeout		= wbint_bh_set_timeout,
	.raw_call_send		= wbint_bh_raw_call_send,
	.raw_call_recv		= wbint_bh_raw_call_recv,
	.disconnect_send	= wbint_bh_disconnect_send,
	.disconnect_recv	= wbint_bh_disconnect_recv,

	.ref_alloc		= wbint_bh_ref_alloc,
	.do_ndr_print		= wbint_bh_do_ndr_print,
};

static NTSTATUS make_internal_ncacn_conn(TALLOC_CTX *mem_ctx,
				const struct ndr_interface_table *table,
				struct dcerpc_ncacn_conn **_out)
{
	struct dcerpc_ncacn_conn *ncacn_conn = NULL;

	ncacn_conn = talloc_zero(mem_ctx, struct dcerpc_ncacn_conn);
	if (ncacn_conn == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	ncacn_conn->p.mem_ctx = mem_ctx;

	*_out = ncacn_conn;

	return NT_STATUS_OK;
}

static NTSTATUS find_ncalrpc_default_endpoint(struct dcesrv_context *dce_ctx,
					      struct dcesrv_endpoint **ep)
{
	TALLOC_CTX *tmp_ctx = NULL;
	struct dcerpc_binding *binding = NULL;
	NTSTATUS status;

	tmp_ctx = talloc_new(dce_ctx);
	if (tmp_ctx == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	/*
	 * Some services use a rpcint binding handle in their initialization,
	 * before the server is fully initialized. Search the NCALRPC endpoint
	 * with and without endpoint
	 */
	status = dcerpc_parse_binding(tmp_ctx, "ncalrpc:", &binding);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = dcesrv_find_endpoint(dce_ctx, binding, ep);
	if (NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = dcerpc_parse_binding(tmp_ctx, "ncalrpc:[WINBIND]", &binding);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = dcesrv_find_endpoint(dce_ctx, binding, ep);
	if (NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = dcerpc_parse_binding(tmp_ctx, "ncalrpc:[DEFAULT]", &binding);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = dcesrv_find_endpoint(dce_ctx, binding, ep);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

out:
	talloc_free(tmp_ctx);
	return status;
}

static NTSTATUS make_internal_dcesrv_connection(TALLOC_CTX *mem_ctx,
				const struct ndr_interface_table *ndr_table,
				struct dcerpc_ncacn_conn *ncacn_conn,
				struct dcesrv_connection **_out)
{
	struct dcesrv_connection *conn = NULL;
	struct dcesrv_connection_context *context = NULL;
	struct dcesrv_endpoint *endpoint = NULL;
	NTSTATUS status;

	conn = talloc_zero(mem_ctx, struct dcesrv_connection);
	if (conn == NULL) {
		return NT_STATUS_NO_MEMORY;
	}
	conn->dce_ctx = global_dcesrv_context();
	conn->preferred_transfer = &ndr_transfer_syntax_ndr;
	conn->transport.private_data = ncacn_conn;

	status = find_ncalrpc_default_endpoint(conn->dce_ctx, &endpoint);
	if (!NT_STATUS_IS_OK(status)) {
		goto fail;
	}
	conn->endpoint = endpoint;

	conn->default_auth_state = talloc_zero(conn, struct dcesrv_auth);
	if (conn->default_auth_state == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto fail;
	}
	conn->default_auth_state->auth_finished = true;

	context = talloc_zero(conn, struct dcesrv_connection_context);
	if (context == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto fail;
	}
	context->conn = conn;
	context->context_id = 0;
	context->transfer_syntax = *(conn->preferred_transfer);
	context->iface = find_interface_by_syntax_id(
		conn->endpoint, &ndr_table->syntax_id);
	if (context->iface == NULL) {
		status = NT_STATUS_RPC_INTERFACE_NOT_FOUND;
		goto fail;
	}

	DLIST_ADD(conn->contexts, context);

	*_out = conn;

	return NT_STATUS_OK;
fail:
	talloc_free(conn);
	return status;
}

static NTSTATUS set_remote_addresses(struct dcesrv_connection *conn,
				     int sock)
{
	struct samba_sockaddr ssa;
	struct tsocket_address *remote = NULL;
	struct tsocket_address *local = NULL;
	NTSTATUS status;
	int ret;

	ssa = (struct samba_sockaddr) { .sa_socklen = sizeof(ssa.u.ss), };
	ret = getpeername(sock, &ssa.u.sa, &ssa.sa_socklen);
	if (ret != 0) {
		status = map_nt_error_from_unix(ret);
		DBG_ERR("getpeername failed: %s\n", nt_errstr(status));
		return status;
	}

	ret = tsocket_address_bsd_from_sockaddr(conn,
						&ssa.u.sa,
						ssa.sa_socklen,
						&remote);
	if (ret != 0) {
		status = map_nt_error_from_unix(ret);
		DBG_ERR("tsocket_address_bsd_from_sockaddr failed: %s\n",
			nt_errstr(status));
		return status;
	}

	ssa = (struct samba_sockaddr) { .sa_socklen = sizeof(ssa.u.ss), };
	ret = getsockname(sock, &ssa.u.sa, &ssa.sa_socklen);
	if (ret != 0) {
		status = map_nt_error_from_unix(ret);
		DBG_ERR("getsockname failed: %s\n", nt_errstr(status));
		return status;
	}

	ret = tsocket_address_bsd_from_sockaddr(conn,
						&ssa.u.sa,
						ssa.sa_socklen,
						&local);
	if (ret != 0) {
		status = map_nt_error_from_unix(ret);
		DBG_ERR("tsocket_address_bsd_from_sockaddr failed: %s\n",
			nt_errstr(status));
		return status;
	}

	conn->local_address = talloc_move(conn, &local);
	conn->remote_address = talloc_move(conn, &remote);

	return NT_STATUS_OK;
}

/* initialise a wbint binding handle */
struct dcerpc_binding_handle *wbint_binding_handle(TALLOC_CTX *mem_ctx,
						struct winbindd_domain *domain,
						struct winbindd_child *child)
{
	struct dcerpc_binding_handle *h = NULL;
	struct wbint_bh_state *hs = NULL;
	struct dcerpc_binding *b = NULL;
	NTSTATUS status;

	SMB_ASSERT(mem_ctx != NULL);

	SMB_ASSERT((domain != NULL && child == NULL) ||
		  (domain == NULL && child != NULL));

	h = dcerpc_binding_handle_create(mem_ctx,
					 &wbint_bh_ops,
					 NULL,
					 &ndr_table_winbind,
					 &hs,
					 struct wbint_bh_state,
					 __location__);
	if (h == NULL) {
		return NULL;
	}
	hs->domain = domain;
	hs->child = child;

	status = dcerpc_parse_binding(hs, "", &b);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(h);
		return NULL;
	}
	status = dcerpc_binding_set_transport(b, NCACN_INTERNAL);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(h);
		return NULL;
	}
	status = dcerpc_binding_set_string_option(b, "host", "localhost");
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(h);
		return NULL;
	}
	status = dcerpc_binding_set_string_option(b,
						  "endpoint",
						  "winbindd_dual_ndrcmd");
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(h);
		return NULL;
	}
	status = dcerpc_binding_set_abstract_syntax(b,
						&ndr_table_winbind.syntax_id);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(h);
		return NULL;
	}

	hs->binding = b;

	return h;
}

enum winbindd_result winbindd_dual_ndrcmd(struct winbindd_domain *domain,
					  struct winbindd_cli_state *state)
{
	struct dcerpc_ncacn_conn *ncacn_conn = NULL;
	struct dcesrv_connection *dcesrv_conn = NULL;
	struct dcesrv_call_state *dcesrv_call = NULL;
	struct data_blob_list_item *rep = NULL;
	struct dcesrv_context_callbacks *cb = NULL;
	uint32_t opnum = state->request->data.ndrcmd;
	TALLOC_CTX *mem_ctx;
	NTSTATUS status;

	DBG_DEBUG("Running command %s (domain '%s')\n",
		  ndr_table_winbind.calls[opnum].name,
		  domain ? domain->name : "(null)");

	mem_ctx = talloc_stackframe();
	if (mem_ctx == NULL) {
		DBG_ERR("No memory\n");
		return WINBINDD_ERROR;
	}

	status = make_internal_ncacn_conn(mem_ctx,
					  &ndr_table_winbind,
					  &ncacn_conn);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = make_internal_dcesrv_connection(ncacn_conn,
						 &ndr_table_winbind,
						 ncacn_conn,
						 &dcesrv_conn);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	status = set_remote_addresses(dcesrv_conn, state->sock);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	dcesrv_call = talloc_zero(dcesrv_conn, struct dcesrv_call_state);
	if (dcesrv_call == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto out;
	}

	dcesrv_call->conn = dcesrv_conn;
	dcesrv_call->context = dcesrv_conn->contexts;
	dcesrv_call->auth_state = dcesrv_conn->default_auth_state;

	ZERO_STRUCT(dcesrv_call->pkt);
	dcesrv_call->pkt.u.bind.assoc_group_id = 0;

	cb = dcesrv_call->conn->dce_ctx->callbacks;
	status = cb->assoc_group.find(
		dcesrv_call, cb->assoc_group.private_data);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	ZERO_STRUCT(dcesrv_call->pkt);
	dcesrv_call->pkt.u.request.opnum = opnum;
	dcesrv_call->pkt.u.request.context_id = 0;
	dcesrv_call->pkt.u.request.stub_and_verifier =
		data_blob_const(state->request->extra_data.data,
				state->request->extra_len);

	status = dcesrv_call_dispatch_local(dcesrv_call);
	if (!NT_STATUS_IS_OK(status)) {
		goto out;
	}

	rep = dcesrv_call->replies;
	DLIST_REMOVE(dcesrv_call->replies, rep);

	state->response->extra_data.data = talloc_steal(state->mem_ctx,
							rep->blob.data);
	state->response->length += rep->blob.length;

	talloc_free(rep);

out:
	talloc_free(mem_ctx);
	if (NT_STATUS_IS_OK(status)) {
		return WINBINDD_OK;
	}
	return WINBINDD_ERROR;
}
