/*
 * checkconf/unbound-control.c - remote control utility for unbound.
 *
 * Copyright (c) 2008, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/**
 * \file
 *
 * The remote control utility contacts the unbound server over ssl and
 * sends the command, receives the answer, and displays the result
 * from the commandline.
 */

#include "config.h"
#include "util/log.h"
#include "util/config_file.h"
#include "util/locks.h"
#include "util/net_help.h"

/** Give unbound-control usage, and exit (1). */
static void
usage()
{
	printf("Usage:	unbound-control [options] command\n");
	printf("	Remote control utility for unbound server.\n");
	printf("Options:\n");
	printf("  -c file	config file, default is %s\n", CONFIGFILE);
	printf("  -s ip[@port]	server address, if omitted config is used.\n");
	printf("  -h		show this usage help.\n");
	printf("Commands:\n");
	printf("  start		start server; runs unbound(8)\n");
	printf("  stop		stops the server\n");
	printf("  reload	reloads the server\n");
	printf("Version %s\n", PACKAGE_VERSION);
	printf("BSD licensed, see LICENSE in source package for details.\n");
	printf("Report bugs to %s\n", PACKAGE_BUGREPORT);
	exit(1);
}

/** exit with ssl error */
static void ssl_err(const char* s)
{
	fprintf(stderr, "error: %s\n", s);
	ERR_print_errors_fp(stderr);
	exit(1);
}

/** setup SSL context */
static SSL_CTX*
setup_ctx(struct config_file* cfg)
{
	char* s_cert, *c_key, *c_cert;
	SSL_CTX* ctx;

	s_cert = fname_after_chroot(cfg->server_cert_file, cfg, 1);
	c_key = fname_after_chroot(cfg->control_key_file, cfg, 1);
	c_cert = fname_after_chroot(cfg->control_cert_file, cfg, 1);
	if(!s_cert || !c_key || !c_cert)
		fatal_exit("out of memory");
        ctx = SSL_CTX_new(SSLv23_client_method());
	if(!ctx)
		ssl_err("could not allocate SSL_CTX pointer");
        if(!(SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2) & SSL_OP_NO_SSLv2))
		ssl_err("could not set SSL_OP_NO_SSLv2");
	if(!SSL_CTX_use_certificate_file(ctx,c_cert,SSL_FILETYPE_PEM) ||
		!SSL_CTX_use_PrivateKey_file(ctx,c_key,SSL_FILETYPE_PEM)
		|| !SSL_CTX_check_private_key(ctx))
		ssl_err("Error setting up SSL_CTX client key and cert");
	if (SSL_CTX_load_verify_locations(ctx, s_cert, NULL) != 1)
		ssl_err("Error setting up SSL_CTX verify, server cert");
	SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);

	free(s_cert);
	free(c_key);
	free(c_cert);
	return ctx;
}

/** contact the server with TCP connect */
static int
contact_server(char* svr, struct config_file* cfg)
{
	struct sockaddr_storage addr;
	socklen_t addrlen;
	int fd;
	/* use svr or the first config entry */
	if(!svr) {
		if(cfg->control_ifs)
			svr = cfg->control_ifs->str;
		else	svr = "127.0.0.1";
	}
	if(strchr(svr, '@')) {
		if(!extstrtoaddr(svr, &addr, &addrlen))
			fatal_exit("could not parse IP@port: %s", svr);
	} else {
		if(!ipstrtoaddr(svr, cfg->control_port, &addr, &addrlen))
			fatal_exit("could not parse IP: %s", svr);
	}
	fd = socket(addr_is_ip6(&addr, addrlen)?AF_INET6:AF_INET, 
		SOCK_STREAM, 0);
	if(fd == -1) {
#ifndef USE_WINSOCK
		fatal_exit("socket: %s", strerror(errno));
#else
		fatal_exit("socket: %s", wsa_strerror(WSAGetLastError()));
#endif
	}
	if(connect(fd, (struct sockaddr*)&addr, addrlen) < 0) {
		log_addr(0, "address", &addr, addrlen);
#ifndef USE_WINSOCK
		log_err("connect: %s", strerror(errno));
#else
		log_err("connect: %s", wsa_strerror(WSAGetLastError()));
#endif
		exit(1);
	}
	return fd;
}

/** setup SSL on the connection */
static SSL*
setup_ssl(SSL_CTX* ctx, int fd)
{
	SSL* ssl;
	X509* x;
	int r;

	ssl = SSL_new(ctx);
	if(!ssl)
		ssl_err("could not SSL_new");
	SSL_set_connect_state(ssl);
	(void)SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
	if(!SSL_set_fd(ssl, fd))
		ssl_err("could not SSL_set_fd");
	while(1) {
		ERR_clear_error();
		if( (r=SSL_do_handshake(ssl)) == 1)
			break;
		r = SSL_get_error(ssl, r);
		if(r != SSL_ERROR_WANT_READ && r != SSL_ERROR_WANT_WRITE)
			ssl_err("SSL handshake failed");
		/* wants to be called again */
	}

	/* check authenticity of server */
	if(SSL_get_verify_result(ssl) != X509_V_OK)
		ssl_err("SSL verification failed");
	x = SSL_get_peer_certificate(ssl);
	if(!x)
		ssl_err("Server presented no peer certificate");
	X509_free(x);
	return ssl;
}

/** send command and display result */
static void
go_cmd(SSL* ssl, int argc, char* argv[])
{
	char* cmd = "GET / HTTP/1.0\n\n";
	int r;
	char buf[1024];
	if(SSL_write(ssl, cmd, (int)strlen(cmd)) <= 0)
		ssl_err("could not SSL_write");
	while(1) {
		ERR_clear_error();
		if((r = SSL_read(ssl, buf, (int)sizeof(buf)-1)) <= 0) {
			if(SSL_get_error(ssl, r) == SSL_ERROR_ZERO_RETURN) {
				/* EOF */
				break;
			}
			ssl_err("could not SSL_read");
		}
		buf[r] = 0;
		printf("%s", buf);
	}
}

/** go ahead and read config, contact server and perform command and display */
static void
go(char* cfgfile, char* svr, int argc, char* argv[])
{
	struct config_file* cfg;
	int fd;
	SSL_CTX* ctx;
	SSL* ssl;

	/* read config */
	if(!(cfg = config_create()))
		fatal_exit("out of memory");
	if(!config_read(cfg, cfgfile))
		fatal_exit("could not read config file");
	if(!cfg->remote_control_enable)
		log_warn("control-enable is 'no' in the config file.");
	ctx = setup_ctx(cfg);
	
	/* contact server */
	fd = contact_server(svr, cfg);
	ssl = setup_ssl(ctx, fd);
	
	/* send command */
	go_cmd(ssl, argc, argv);

	SSL_free(ssl);
	close(fd);
	SSL_CTX_free(ctx);
	config_delete(cfg);
}

/** getopt global, in case header files fail to declare it. */
extern int optind;
/** getopt global, in case header files fail to declare it. */
extern char* optarg;

/** Main routine for unbound-control */
int main(int argc, char* argv[])
{
	int c;
	char* cfgfile = CONFIGFILE;
	char* svr = NULL;
	log_ident_set("unbound-control");
	log_init(NULL, 0, NULL);
	checklock_start();
#ifdef USE_WINSOCK
	if((r = WSAStartup(MAKEWORD(2,2), &wsa_data)) != 0)
		fatal_exit("WSAStartup failed: %s", wsa_strerror(r));
#endif

	ERR_load_crypto_strings();
	ERR_load_SSL_strings();
	OpenSSL_add_all_algorithms();
	(void)SSL_library_init();

	if(!RAND_status()) {
                /* try to seed it */
                unsigned char buf[256];
                unsigned int v, seed=(unsigned)time(NULL) ^ (unsigned)getpid();
                size_t i;
                for(i=0; i<256/sizeof(v); i++) {
                        memmove(buf+i*sizeof(v), &v, sizeof(v));
                        v = v*seed + (unsigned int)i;
                }
                RAND_seed(buf, 256);
		log_warn("no entropy, seeding openssl PRNG with time\n");
	}

	/* parse the options */
	while( (c=getopt(argc, argv, "c:s:h")) != -1) {
		switch(c) {
		case 'c':
			cfgfile = optarg;
			break;
		case 's':
			svr = optarg;
			break;
		case '?':
		case 'h':
		default:
			usage();
		}
	}
	argc -= optind;
	argv += optind;
	if(argc == 0)
		usage();
	if(argc == 1 && strcmp(argv[0], "start")==0) {
		if(execlp("unbound", "unbound", "-c", cfgfile, 
			(char*)NULL) < 0) {
			fatal_exit("could not exec unbound: %s",
				strerror(errno));
		}
	}

	go(cfgfile, svr, argc, argv);

#ifdef USE_WINSOCK
        WSACleanup();
#endif
	checklock_stop();
	return 0;
}