/* 
   Unix SMB/CIFS implementation.
   remote dcerpc operations

   Copyright (C) Stefan (metze) Metzmacher 2004
   Copyright (C) Julien Kerihuel 2008-2009
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2010

   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 <tevent.h>
#include "rpc_server/dcerpc_server.h"
#include "auth/auth.h"
#include "auth/credentials/credentials.h"
#include "librpc/rpc/dcerpc.h"
#include "librpc/ndr/ndr_table.h"
#include "param/param.h"

NTSTATUS dcerpc_server_remote_init(TALLOC_CTX *ctx);

#define DCESRV_REMOTE_ASSOC_MAGIC 0x782f50c4
struct dcesrv_remote_assoc {
	uint32_t assoc_group_id;
};

#define DCESRV_REMOTE_PRIVATE_MAGIC 0x7eceafa6
struct dcesrv_remote_private {
	struct dcerpc_pipe *c_pipe;
};

static NTSTATUS remote_op_reply(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx, void *r)
{
	return NT_STATUS_OK;
}

static NTSTATUS remote_op_bind(struct dcesrv_connection_context *context,
			       const struct dcesrv_interface *iface)
{
	return NT_STATUS_OK;
}

static NTSTATUS remote_get_private(struct dcesrv_call_state *dce_call,
				   struct dcesrv_remote_private **_priv)
{
	const struct ndr_interface_table *table =
		(const struct ndr_interface_table *)dce_call->context->iface->private_data;
	struct dcesrv_remote_private *priv = NULL;
	struct dcesrv_remote_assoc *assoc = NULL;
	const char *binding = NULL;
	const char *user, *pass, *domain;
	struct cli_credentials *credentials;
	bool must_free_credentials = false;
	bool machine_account;
	bool allow_anonymous;
	struct dcerpc_binding		*b;
	struct composite_context	*pipe_conn_req;
	uint32_t flags = 0;
	NTSTATUS status;

	priv = dcesrv_iface_state_find_conn(dce_call,
					    DCESRV_REMOTE_PRIVATE_MAGIC,
					    struct dcesrv_remote_private);
	if (priv != NULL) {
		*_priv = priv;
		return NT_STATUS_OK;
	}

	priv = talloc_zero(dce_call, struct dcesrv_remote_private);
	if (priv == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	assoc = dcesrv_iface_state_find_assoc(dce_call,
					DCESRV_REMOTE_ASSOC_MAGIC,
					struct dcesrv_remote_assoc);
	if (assoc == NULL) {
		assoc = talloc_zero(dce_call, struct dcesrv_remote_assoc);
		if (assoc == NULL) {
			return NT_STATUS_NO_MEMORY;
		}
	}

	binding = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx,
				    NULL,
				    "dcerpc_remote",
				    "binding");
	if (binding == NULL) {
		DEBUG(0,("You must specify a DCE/RPC binding string\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	user = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx, NULL, "dcerpc_remote", "user");
	pass = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx, NULL, "dcerpc_remote", "password");
	domain = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx, NULL, "dceprc_remote", "domain");

	machine_account = lpcfg_parm_bool(dce_call->conn->dce_ctx->lp_ctx,
					  NULL,
					  "dcerpc_remote",
					  "use_machine_account",
					  false);
	allow_anonymous = lpcfg_parm_bool(dce_call->conn->dce_ctx->lp_ctx,
					  NULL,
					  "dcerpc_remote",
					  "allow_anonymous_fallback",
					  false);

	credentials = dcesrv_call_credentials(dce_call);

	if (user && pass) {
		bool ok;

		DEBUG(5, ("dcerpc_remote: RPC Proxy: Using specified account\n"));
		credentials = cli_credentials_init(priv);
		if (!credentials) {
			return NT_STATUS_NO_MEMORY;
		}
		must_free_credentials = true;

		ok = cli_credentials_set_conf(credentials,
					      dce_call->conn->dce_ctx->lp_ctx);
		if (!ok) {
			return NT_STATUS_INTERNAL_ERROR;
		}

		cli_credentials_set_username(credentials, user, CRED_SPECIFIED);
		if (domain) {
			cli_credentials_set_domain(credentials, domain, CRED_SPECIFIED);
		}
		cli_credentials_set_password(credentials, pass, CRED_SPECIFIED);
	} else if (machine_account) {
		DEBUG(5, ("dcerpc_remote: RPC Proxy: Using machine account\n"));
		credentials = cli_credentials_init_server(
				priv,
				dce_call->conn->dce_ctx->lp_ctx);
		if (!credentials) {
			return NT_STATUS_NO_MEMORY;
		}
		must_free_credentials = true;
	} else if (credentials != NULL) {
		DEBUG(5, ("dcerpc_remote: RPC Proxy: Using delegated credentials\n"));
	} else if (allow_anonymous) {
		DEBUG(5, ("dcerpc_remote: RPC Proxy: Using anonymous\n"));
		credentials = cli_credentials_init_anon(priv);
		if (!credentials) {
			return NT_STATUS_NO_MEMORY;
		}
		must_free_credentials = true;
	} else {
		DEBUG(1,("dcerpc_remote: RPC Proxy: You must supply binding, user and password or have delegated credentials\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	/* parse binding string to the structure */
	status = dcerpc_parse_binding(priv, binding, &b);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0, ("Failed to parse dcerpc binding '%s'\n", binding));
		return status;
	}

	/* If we already have a remote association group ID, then use that */
	if (assoc->assoc_group_id != 0) {
		status = dcerpc_binding_set_assoc_group_id(b,
			assoc->assoc_group_id);
		if (!NT_STATUS_IS_OK(status)) {
			DEBUG(0, ("dcerpc_binding_set_assoc_group_id() - %s'\n",
				  nt_errstr(status)));
			return status;
		}
	}

	status = dcerpc_binding_set_abstract_syntax(b, &table->syntax_id);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0, ("dcerpc_binding_set_abstract_syntax() - %s'\n",
			  nt_errstr(status)));
		return status;
	}

	if (dce_call->conn->state_flags & DCESRV_CALL_STATE_FLAG_MULTIPLEXED) {
		status = dcerpc_binding_set_flags(b, DCERPC_CONCURRENT_MULTIPLEX, 0);
		if (!NT_STATUS_IS_OK(status)) {
			DEBUG(0, ("dcerpc_binding_set_flags(CONC_MPX) - %s'\n",
				  nt_errstr(status)));
			return status;
		}
	}

	DEBUG(3, ("Using binding %s\n", dcerpc_binding_string(dce_call->context, b)));

	pipe_conn_req = dcerpc_pipe_connect_b_send(priv, b, table,
						   credentials, dce_call->event_ctx, dce_call->conn->dce_ctx->lp_ctx);
	status = dcerpc_pipe_connect_b_recv(pipe_conn_req, priv, &(priv->c_pipe));
	
	if (must_free_credentials) {
		talloc_free(credentials);
	}

	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	if (dce_call->conn->state_flags & DCESRV_CALL_STATE_FLAG_MULTIPLEXED) {
		flags = dcerpc_binding_get_flags(priv->c_pipe->binding);
		if (!(flags & DCERPC_CONCURRENT_MULTIPLEX)) {
			DEBUG(1,("dcerpc_remote: RPC Proxy: "
				 "Remote server doesn't support MPX\n"));
			return NT_STATUS_INVALID_NETWORK_RESPONSE;
		}
	}

	if (assoc->assoc_group_id == 0) {
		assoc->assoc_group_id =
			dcerpc_binding_get_assoc_group_id(priv->c_pipe->binding);
		if (assoc->assoc_group_id == 0) {
			return NT_STATUS_INVALID_NETWORK_RESPONSE;
		}

		status = dcesrv_iface_state_store_assoc(dce_call,
						DCESRV_REMOTE_ASSOC_MAGIC,
						assoc);
		if (!NT_STATUS_IS_OK(status)) {
			return status;
		}
	}

	status = dcesrv_iface_state_store_conn(dce_call,
					DCESRV_REMOTE_PRIVATE_MAGIC,
					priv);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	*_priv = priv;
	return NT_STATUS_OK;
}

static NTSTATUS remote_op_ndr_pull(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx, struct ndr_pull *pull, void **r)
{
	enum ndr_err_code ndr_err;
	const struct ndr_interface_table *table = (const struct ndr_interface_table *)dce_call->context->iface->private_data;
	uint16_t opnum = dce_call->pkt.u.request.opnum;

	dce_call->fault_code = 0;

	if (opnum >= table->num_calls) {
		dce_call->fault_code = DCERPC_FAULT_OP_RNG_ERROR;
		return NT_STATUS_NET_WRITE_FAULT;
	}

	/*
	 * We don't have support for calls with pipes.
	 */
	if (table->calls[opnum].in_pipes.num_pipes != 0) {
		dce_call->fault_code = DCERPC_FAULT_OP_RNG_ERROR;
		return NT_STATUS_NET_WRITE_FAULT;
	}
	if (table->calls[opnum].out_pipes.num_pipes != 0) {
		dce_call->fault_code = DCERPC_FAULT_OP_RNG_ERROR;
		return NT_STATUS_NET_WRITE_FAULT;
	}

	*r = talloc_size(mem_ctx, table->calls[opnum].struct_size);
	if (!*r) {
		return NT_STATUS_NO_MEMORY;
	}

        /* unravel the NDR for the packet */
	ndr_err = table->calls[opnum].ndr_pull(pull, NDR_IN, *r);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		dce_call->fault_code = DCERPC_FAULT_NDR;
		return NT_STATUS_NET_WRITE_FAULT;
	}

	return NT_STATUS_OK;
}

static void remote_op_dispatch_done(struct tevent_req *subreq);

struct dcesrv_remote_call {
	struct dcesrv_call_state *dce_call;
	struct dcesrv_remote_private *priv;
};

static NTSTATUS remote_op_dispatch(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx, void *r)
{
	struct dcesrv_remote_call *rcall = NULL;
	struct dcesrv_remote_private *priv = NULL;
	uint16_t opnum = dce_call->pkt.u.request.opnum;
	const struct ndr_interface_table *table = dce_call->context->iface->private_data;
	const struct ndr_interface_call *call;
	const char *name;
	struct tevent_req *subreq;
	NTSTATUS status;

	name = table->calls[opnum].name;
	call = &table->calls[opnum];

	status = remote_get_private(dce_call, &priv);
	if (!NT_STATUS_IS_OK(status)) {
		DEBUG(0,("dcesrv_remote: call[%s] %s\n", name, nt_errstr(status)));
		return status;
	}

	rcall = talloc_zero(dce_call, struct dcesrv_remote_call);
	if (rcall == NULL) {
		return NT_STATUS_NO_MEMORY;
	}
	rcall->dce_call = dce_call;
	rcall->priv = priv;

	if (priv->c_pipe->conn->flags & DCERPC_DEBUG_PRINT_IN) {
		ndr_print_function_debug(call->ndr_print, name, NDR_IN | NDR_SET_VALUES, r);		
	}

	priv->c_pipe->conn->flags |= DCERPC_NDR_REF_ALLOC;

	/* we didn't use the return code of this function as we only check the last_fault_code */
	subreq = dcerpc_binding_handle_call_send(rcall, dce_call->event_ctx,
						 priv->c_pipe->binding_handle,
						 NULL, table,
						 opnum, mem_ctx, r);
	if (subreq == NULL) {
		DEBUG(0,("dcesrv_remote: call[%s] dcerpc_binding_handle_call_send() failed!\n", name));
		return NT_STATUS_NO_MEMORY;
	}
	tevent_req_set_callback(subreq, remote_op_dispatch_done, rcall);

	dce_call->state_flags |= DCESRV_CALL_STATE_FLAG_ASYNC;
	return NT_STATUS_OK;
}

static void remote_op_dispatch_done(struct tevent_req *subreq)
{
	struct dcesrv_remote_call *rcall =
		tevent_req_callback_data(subreq,
		struct dcesrv_remote_call);
	struct dcesrv_call_state *dce_call = rcall->dce_call;
	struct dcesrv_remote_private *priv = rcall->priv;
	uint16_t opnum = dce_call->pkt.u.request.opnum;
	const struct ndr_interface_table *table = dce_call->context->iface->private_data;
	const struct ndr_interface_call *call;
	const char *name;
	NTSTATUS status;

	name = table->calls[opnum].name;
	call = &table->calls[opnum];

	/* we didn't use the return code of this function as we only check the last_fault_code */
	status = dcerpc_binding_handle_call_recv(subreq);
	TALLOC_FREE(subreq);

	dce_call->fault_code = priv->c_pipe->last_fault_code;
	if (dce_call->fault_code != 0) {
		DEBUG(0,("dcesrv_remote: call[%s] failed with: %s!\n",
			name, dcerpc_errstr(dce_call, dce_call->fault_code)));
		goto reply;
	}

	if (NT_STATUS_IS_OK(status) &&
	    (priv->c_pipe->conn->flags & DCERPC_DEBUG_PRINT_OUT)) {
		ndr_print_function_debug(call->ndr_print, name, NDR_OUT, dce_call->r);
	}

reply:
	_dcesrv_async_reply(dce_call, __func__, name);
}

static NTSTATUS remote_op_ndr_push(struct dcesrv_call_state *dce_call, TALLOC_CTX *mem_ctx, struct ndr_push *push, const void *r)
{
	enum ndr_err_code ndr_err;
	const struct ndr_interface_table *table = dce_call->context->iface->private_data;
	uint16_t opnum = dce_call->pkt.u.request.opnum;

        /* unravel the NDR for the packet */
	ndr_err = table->calls[opnum].ndr_push(push, NDR_OUT, r);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		dce_call->fault_code = DCERPC_FAULT_NDR;
		return NT_STATUS_NET_WRITE_FAULT;
	}

	return NT_STATUS_OK;
}

static NTSTATUS remote_register_one_iface(struct dcesrv_context *dce_ctx, const struct dcesrv_interface *iface)
{
	unsigned int i;
	const struct ndr_interface_table *table = iface->private_data;

	for (i=0;i<table->endpoints->count;i++) {
		NTSTATUS ret;
		const char *name = table->endpoints->names[i];

		ret = dcesrv_interface_register(dce_ctx, name, NULL, iface, NULL);
		if (!NT_STATUS_IS_OK(ret)) {
			DEBUG(1,("remote_op_init_server: failed to register endpoint '%s'\n",name));
			return ret;
		}
	}

	return NT_STATUS_OK;
}

static NTSTATUS remote_op_init_server(struct dcesrv_context *dce_ctx, const struct dcesrv_endpoint_server *ep_server)
{
	unsigned int i;
	char **ifaces = str_list_make(dce_ctx, lpcfg_parm_string(dce_ctx->lp_ctx, NULL, "dcerpc_remote", "interfaces"),NULL);

	if (!ifaces) {
		DEBUG(3,("remote_op_init_server: no interfaces configured\n"));
		return NT_STATUS_OK;
	}

	for (i=0;ifaces[i];i++) {
		NTSTATUS ret;
		struct dcesrv_interface iface;
		
		if (!ep_server->interface_by_name(&iface, ifaces[i])) {
			DEBUG(0,("remote_op_init_server: failed to find interface = '%s'\n", ifaces[i]));
			talloc_free(ifaces);
			return NT_STATUS_UNSUCCESSFUL;
		}

		ret = remote_register_one_iface(dce_ctx, &iface);
		if (!NT_STATUS_IS_OK(ret)) {
			DEBUG(0,("remote_op_init_server: failed to register interface = '%s'\n", ifaces[i]));
			talloc_free(ifaces);
			return ret;
		}
	}

	talloc_free(ifaces);
	return NT_STATUS_OK;
}

static NTSTATUS remote_op_shutdown_server(struct dcesrv_context *dce_ctx,
				const struct dcesrv_endpoint_server *ep_server)
{
	return NT_STATUS_OK;
}

static bool remote_fill_interface(struct dcesrv_interface *iface, const struct ndr_interface_table *if_tabl)
{
	iface->name = if_tabl->name;
	iface->syntax_id = if_tabl->syntax_id;
	
	iface->bind = remote_op_bind;
	iface->unbind = NULL;

	iface->ndr_pull = remote_op_ndr_pull;
	iface->dispatch = remote_op_dispatch;
	iface->reply = remote_op_reply;
	iface->ndr_push = remote_op_ndr_push;

	iface->private_data = if_tabl;
	iface->flags = 0;

	return true;
}

static bool remote_op_interface_by_uuid(struct dcesrv_interface *iface, const struct GUID *uuid, uint32_t if_version)
{
	const struct ndr_interface_list *l;

	for (l=ndr_table_list();l;l=l->next) {
		if (l->table->syntax_id.if_version == if_version &&
			GUID_equal(&l->table->syntax_id.uuid, uuid)==0) {
			return remote_fill_interface(iface, l->table);
		}
	}

	return false;	
}

static bool remote_op_interface_by_name(struct dcesrv_interface *iface, const char *name)
{
	const struct ndr_interface_table *tbl = ndr_table_by_name(name);

	if (tbl)
		return remote_fill_interface(iface, tbl);

	return false;	
}

NTSTATUS dcerpc_server_remote_init(TALLOC_CTX *ctx)
{
	NTSTATUS ret;
	static const struct dcesrv_endpoint_server ep_server = {
		/* fill in our name */
		.name = "remote",

		.initialized = false,

		/* fill in all the operations */
		.init_server = remote_op_init_server,
		.shutdown_server = remote_op_shutdown_server,

		.interface_by_uuid = remote_op_interface_by_uuid,
		.interface_by_name = remote_op_interface_by_name
	};

	/* register ourselves with the DCERPC subsystem. */
	ret = dcerpc_register_ep_server(&ep_server);
	if (!NT_STATUS_IS_OK(ret)) {
		DEBUG(0,("Failed to register 'remote' endpoint server!\n"));
		return ret;
	}

	/* We need the full DCE/RPC interface table */
	ndr_table_init();

	return ret;
}