/*
 * Copyright 2008 Red Hat, Inc.
 *
 * 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; version 2 of the License.
 *
 * 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, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307 USA
 *
 */

#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#include <rpc/rpc.h>
#include <rpc/pmap_clnt.h>
#include <rpcsvc/yp_prot.h>

#ifdef HAVE_TCPD_H
#include <tcpd.h>
#endif

#ifdef HAVE_DIRSRV_SLAPI_PLUGIN_H
#include <nspr.h>
#include <nss.h>
#include <dirsrv/slapi-plugin.h>
#else
#include <slapi-plugin.h>
#endif

#include "wrap.h"
#include "disp-nis.h"
#include "map.h"
#include "nis.h"
#include "plugin.h"
#include "portmap.h"

/* the module initialization function */
static Slapi_PluginDesc
plugin_description = {
	.spd_id = "nis-plugin",
	.spd_vendor = "redhat.com",
	.spd_version = PACKAGE_VERSION,
	.spd_description = "NIS Server Plugin",
};

/* Start the plugin's work thread. */
static int
plugin_startup(Slapi_PBlock *pb)
{
	struct plugin_state *state;
	const char *pname;
	int i, protocol;
	slapi_pblock_get(pb, SLAPI_PLUGIN_PRIVATE, &state);
	slapi_pblock_get(pb, SLAPI_TARGET_DN, &state->plugin_base);
	/* Populate the maps and data. */
	map_startup(state);
	/* Register the listener sockets with the portmapper. */
	if (state->pmap_client_socket != -1) {
		/* kick off any other NIS servers */
		portmap_unregister(plugin_description.spd_id,
				   state->pmap_client_socket,
				   YPPROG, YPVERS);
		/* register our ports */
		for (i = 0; i < state->n_listeners; i++) {
			switch (state->listener[i].type) {
			case SOCK_DGRAM:
				protocol = IPPROTO_UDP;
				pname = "UDP";
				break;
			case SOCK_STREAM:
				protocol = IPPROTO_TCP;
				pname = "TCP";
				break;
			default:
				/* never reached */
				assert(0);
				break;
			}
			if (protocol == IPPROTO_IP) {
				continue;
			}
			if (!portmap_register(plugin_description.spd_id,
					      state->pmap_client_socket,
					      YPPROG, YPVERS, protocol,
					      state->listener[i].port)) {
				slapi_log_error(SLAPI_LOG_PLUGIN,
						plugin_description.spd_id,
						"error registering %s service "
						"with portmap\n", pname);
			}
		}
	}
	/* Start a new listening thread to handle incoming traffic. */
	state->tid = wrap_start_thread(&dispatch_thread, state);
	if (state->tid == NULL) {
		slapi_log_error(SLAPI_LOG_PLUGIN,
				plugin_description.spd_id,
				"error starting listener thread\n");
		return -1;
	}
	slapi_log_error(SLAPI_LOG_PLUGIN, plugin_description.spd_id,
			"plugin startup completed\n");
	return 0;
}

/* Stop the plugin's work thread. */
static int
plugin_shutdown(Slapi_PBlock *pb)
{
	struct plugin_state *state;
	slapi_pblock_get(pb, SLAPI_PLUGIN_PRIVATE, &state);
	wrap_stop_thread(state->tid);
	if (state->pmap_client_socket != -1) {
		/* Clear our registration with the portmapper. */
		portmap_unregister(plugin_description.spd_id,
				   state->pmap_client_socket, YPPROG, YPVERS);
	}
	free(state);
	return 0;
}

/* Read the parameters which we need at initialization-time. */
static void
plugin_read_config(Slapi_PBlock *plugin_pb, int *port)
{
	Slapi_ComponentId *id;
	const char *dn, **argv = NULL;
	int argc = 0, i;

	*port = 0;

	slapi_pblock_get(plugin_pb, SLAPI_PLUGIN_IDENTITY, &id);
	slapi_pblock_get(plugin_pb, SLAPI_TARGET_DN, &dn);
	slapi_pblock_get(plugin_pb, SLAPI_PLUGIN_ARGC, &argc);
	slapi_pblock_get(plugin_pb, SLAPI_PLUGIN_ARGV, &argv);
	for (i = 0; (i < argc) && (argv != NULL) && (argv[i] != NULL); i++) {
		switch (i) {
		case 0:
			*port = atoi(argv[i]);
			slapi_log_error(SLAPI_LOG_PLUGIN,
					plugin_description.spd_id,
					"argument 0 (port) = %d\n", *port);
			break;
		}
	}
}

/* Handle the part of startup that needs to be done before we drop privileges:
 * bind to listening ports. */
static int
plugin_state_init(Slapi_PBlock *pb, struct plugin_state **lstate)
{
	int port, sockfd = -1, err, i;
	struct plugin_state *state = NULL;
	struct sockaddr_in sin;
	struct sockaddr_in6 sin6;

	state = malloc(sizeof(*state));
	if (state == NULL) {
		goto failed;
	}
	memset(state, 0, sizeof(*state));
	state->plugin_base = NULL;
	state->plugin_desc = &plugin_description;
	state->max_value_size = DEFAULT_MAX_VALUE_SIZE;
	state->max_dgram_size = DEFAULT_MAX_DGRAM_SIZE;
	slapi_pblock_get(pb, SLAPI_PLUGIN_IDENTITY, &state->plugin_identity);
	slapi_pblock_get(pb, SLAPI_TARGET_DN, &state->plugin_base);
	slapi_log_error(SLAPI_LOG_PLUGIN, state->plugin_desc->spd_id,
			"init: target-dn is %s%s%s\n",
			state->plugin_base ? "\"" : "",
			state->plugin_base ? state->plugin_base : "NULL",
			state->plugin_base ? "\"" : "");
	plugin_read_config(pb, &port);

#ifdef HAVE_TCPD_H
	state->request_info = malloc(sizeof(*(state->request_info)));
	if ((state->request_info == NULL) ||
	    (request_init(state->request_info, 0) != state->request_info) ||
	    (request_set(state->request_info,
			 RQ_DAEMON, DEFAULT_TCPWRAP_NAME,
			 0) != state->request_info)) {
		slapi_log_error(SLAPI_LOG_PLUGIN, state->plugin_desc->spd_id,
				"error initializing tcp_wrappers for \"%s\"\n",
				plugin_description.spd_id);
		return -1;
	}
#else
	state->request_info = NULL;
#endif

	/* Create a socket for use in communicating with the portmapper. */
	sockfd = socket(PF_INET, SOCK_DGRAM, 0);
	if (sockfd == -1) {
		goto failed;
	}
	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	if (bindresvport(sockfd, &sin) != 0) {
		close(sockfd);
		goto failed;
	}
	state->pmap_client_socket = sockfd;

	/* We need to bind on privileged ports for both datagram and connected
	 * listeners, over both IPv4 and IPv6. */
	state->n_listeners = 0;
	for (i = 0; i < 2; i++) {
		int pf, type, one, flags, ret;
		const char *sock_desc;
		/* Before we do anything else, on our second trip through, make
		 * sure that the first socket was created, because we'll need
		 * it for communicating with the portmapper. */
		if ((i > 0) && (state->n_listeners == 0)) {
			slapi_log_error(SLAPI_LOG_PLUGIN,
					plugin_description.spd_id,
					"no socket available to use for "
					"communicating with portmapper\n");
			continue;
		}
		/* Figure out what kind of socket we need, and a textual
		 * term to use in log messages. */
		pf = (i & 2) ? PF_INET6 : PF_INET;
		type = (i & 1) ? SOCK_STREAM : SOCK_DGRAM;
		sock_desc = (i & 2) ? ((i & 1) ? "tcp6" : "udp6") :
				      ((i & 1) ? "tcp" : "udp");
		/* Allocate the socket. */
		sockfd = socket(pf, type, 0);
		if (sockfd == -1) {
			slapi_log_error(SLAPI_LOG_PLUGIN,
					plugin_description.spd_id,
					"error creating a %s socket\n",
					sock_desc);
			continue;
		}
		/* Mark the socket as reusable and non-blocking. */
		one = 1;
		if (setsockopt(sockfd, IPPROTO_IP, SO_REUSEADDR,
			       &one, sizeof(one)) != 0) {
			slapi_log_error(SLAPI_LOG_PLUGIN,
					plugin_description.spd_id,
					"error marking %s socket for reuse, "
					"continuing\n", sock_desc);
		}
		flags = fcntl(sockfd, F_GETFL);
		if ((flags & O_NONBLOCK) == 0) {
			fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
		}
		/* Bind to the server port. */
		memset(&sin, 0, sizeof(sin));
		memset(&sin6, 0, sizeof(sin6));
		sin.sin_family = AF_INET;
		sin6.sin6_family = AF_INET6;
		if (port == 0) {
			ret = (pf == PF_INET6) ? bindresvport(sockfd,
							      (struct sockaddr_in*) &sin6) :
						 bindresvport(sockfd,
							      &sin);
		} else {
			sin.sin_port = htons(port);
			sin6.sin6_port = htons(port);
			ret = (pf == PF_INET6) ? bind(sockfd,
						      (struct sockaddr*) &sin6,
						      sizeof(sin6)) :
						 bind(sockfd,
						      (struct sockaddr*) &sin,
						      sizeof(sin));
		}
		if (ret != 0) {
			slapi_log_error(SLAPI_LOG_PLUGIN,
					plugin_description.spd_id,
					"error binding %s socket to a "
					"privileged port: %s\n",
					sock_desc, strerror(errno));
			close(sockfd);
			continue;
		}
		/* Pick out the port number that we got back, in case we used
		 * bindresvport[6]. */
		port = (pf == PF_INET6) ? ntohs(sin6.sin6_port) :
					  ntohs(sin.sin_port);
		/* If it's a listening socket, let the kernel know that we're
		 * ready to accept client connections. */
		if (type == SOCK_STREAM) {
			if (listen(sockfd, 128) == -1) {
				slapi_log_error(SLAPI_LOG_PLUGIN,
						plugin_description.spd_id,
						"error marking %s socket for "
						"listening: %s\n", sock_desc,
						strerror(errno));
				close(sockfd);
				continue;
			}
		}
		/* Save the other info. */
		state->listener[state->n_listeners].fd = sockfd;
		state->listener[state->n_listeners].port = port;
		state->listener[state->n_listeners].pf = pf;
		state->listener[state->n_listeners].type = type;
		slapi_log_error(SLAPI_LOG_PLUGIN,
				plugin_description.spd_id,
				"listening on port %d for %s clients\n",
				state->listener[state->n_listeners].port,
				sock_desc);
		state->n_listeners++;
	}
	slapi_log_error(SLAPI_LOG_PLUGIN,
			plugin_description.spd_id,
			"set up %d listening sockets\n", state->n_listeners);
	*lstate = state;
	return 0;
failed:
	err = errno;
	free(state);
	errno = err;
	return -1;
}

int
nis_plugin_init(Slapi_PBlock *pb)
{
	struct plugin_state *state = NULL;
	/* Allocate a memory pool and start listening for connections. */
	if (plugin_state_init(pb, &state) == -1) {
		slapi_log_error(SLAPI_LOG_PLUGIN, plugin_description.spd_id,
				"error setting up plugin\n");
		return -1;
	}
	/* Register the plugin with the server. */
	slapi_pblock_set(pb, SLAPI_PLUGIN_VERSION, SLAPI_PLUGIN_VERSION_03);
	slapi_pblock_set(pb, SLAPI_PLUGIN_DESCRIPTION, &plugin_description);
	slapi_pblock_set(pb, SLAPI_PLUGIN_START_FN, &plugin_startup);
	slapi_pblock_set(pb, SLAPI_PLUGIN_CLOSE_FN, &plugin_shutdown);
	slapi_pblock_set(pb, SLAPI_PLUGIN_PRIVATE, state);
	/* Let the backend do its registration. */
	map_init(pb, state);
	slapi_log_error(SLAPI_LOG_PLUGIN, state->plugin_desc->spd_id,
			"registered plugin hooks\n");
	return 0;
}