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version 2.0

/*************************************************************************
 * (C) 2011 AITNET - Sofia/Bulgaria - <office@aitnet.org>
 *  by Michael Pounov <misho@elwix.org>
 *
 * $Author: misho $
 * $Id: ansh3d.c,v 1.5 2015/05/19 23:25:30 misho Exp $
 *
 *************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. 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.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET 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 AITNET 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.
*/
#include "global.h"
#include "anshd.h"
#include "proc.h"


intptr_t Kill;
int Verbose;
u_int Crypted = 1;
proc_head_t pH;
int bpfLEN, Timeout = 300, Daemon = 1;
char Key[STRSIZ];

static struct tagProc *proc;
static sched_root_task_t *root;

extern char compiled[], compiledby[], compilehost[];

static void
Usage()
{
	printf(	" -= anshd =- ELWIX Layer3 remote management service over ICMP\n"
		"=== %s === %s@%s ===\n\n"
		" Syntax: ansh3d [options]\n\n"
		"\t-a <host>\tBind to host address (default is *any*)\n"
		"\t-i <id>\tService ID (default is 42)\n"
		"\t-U <user>\tRun service with other user\n"
		"\t-C <dir>\tRun service into chroot directory\n"
		"\t-t <timeout>\tTimeout of login if no activity (default is 300 sec)\n"
		"\t-k <key>\tService cipher key\n"
		"\t-u\t\tSwitch to unencrypted traffic between hosts\n"
		"\t-b\t\tRun into batch mode (default is daemon mode)\n"
		"\t-v\t\tVerbose (more -v, more verbosity ...)\n"
		"\t-h\t\tThis help screen!\n"
		"\n", compiled, compiledby, compilehost);
}

static void
sig(int s)
{
	int state;
	pid_t pid;

	switch (s) {
		case SIGHUP:
			VERB(1) LOG("Got SIGHUP!\n");
			break;
		case SIGTERM:
			Kill++;
			VERB(1) LOG("Got SIGTERM!\n");
			break;
		case SIGPIPE:
			VERB(1) LOG("Got SIGPIPE!\n");
			break;
		case SIGCHLD:
			VERB(1) LOG("Got SIGCHLD!\n");
			while ((pid = waitpid(-1, &state, WNOHANG)) > 0)
				stopProcess(root, &pH, pid, icmpTx);
			break;
	}
}

static void *
hook_error(void *root, void *arg)
{
/*	sched_root_task_t *r = root; */

	if (!root)
		return (void*) -1;

	if (arg == (void*) EINTR)
		return (void*) -1;

	return NULL;
}

int
main(int argc, char **argv)
{
	sockaddr_t sa;
	struct hostent *host;
	struct passwd *pass;
	int fd, h = 0, uid = 0, gid = 0;
	long id = ANSH_ID;
	char ch, szUser[STRSIZ] = "root", szChroot[STRSIZ] = "/";
	struct sigaction sact;

	memset(&sa, 0, sizeof sa);
	strlcpy(Key, DEFAULT_KEY, sizeof Key);

	while ((ch = getopt(argc, argv, "hvubt:a:i:U:C:k:")) != -1)
		switch (ch) {
			case 'U':
				pass = getpwnam(optarg);
				if (!pass) {
					printf("Error:: User %s not found!\n", optarg);
					return 1;
				} else {
					strlcpy(szUser, optarg, sizeof szUser);
					uid = pass->pw_uid;
					gid = pass->pw_gid;
				}
				endpwent();
				break;
			case 'C':
				if (access(optarg, R_OK)) {
					printf("Error:: in chroot %s #%d - %s\n", optarg, errno, strerror(errno));
					return 1;
				} else
					strlcpy(szChroot, optarg, sizeof szChroot);
				break;
			case 'i':
				id = strtol(optarg, NULL, 0);
				break;
			case 't':
				Timeout = abs(strtol(optarg, NULL, 0));
				break;
			case 'k':
				strlcpy(Key, optarg, sizeof Key);
				break;
			case 'a':
				host = gethostbyname(optarg);
				if (!host) {
					printf("Error:: in bind address '%s' #%d - %s\n", 
							optarg, h_errno, hstrerror(h_errno));
					return 1;
				}
				switch (host->h_addrtype) {
					case AF_INET:
						sa.sin.sin_len = sizeof(struct sockaddr_in);
						sa.sin.sin_family = AF_INET;
						memcpy(&sa.sin.sin_addr.s_addr, host->h_addr, host->h_length);
						break;
					case AF_INET6:
						sa.sin6.sin6_len = sizeof(struct sockaddr_in6);
						sa.sin6.sin6_family = AF_INET6;
						memcpy(&sa.sin6.sin6_addr.s6_addr, host->h_addr, host->h_length);
						break;
					default:
						printf("Error:: Unknown address type %d !!!\n", host->h_addrtype);
						return 1;
				}
				break;
			case 'u':
				Crypted ^= Crypted;
				break;
			case 'b':
				Daemon ^= Daemon;
				break;
			case 'v':
				Verbose++;
				break;
			case 'h':
			default:
				Usage();
				return 1;
		}
	argc -= optind;
	argv += optind;

	/* sanity check for openned descriptor */
	if (!sa.sa.sa_family) {
		sa.sin.sin_len = sizeof(struct sockaddr_in);
		sa.sin.sin_family = AF_INET;
	}

	/* catch signals */
	memset(&sact, 0, sizeof sact);
	sigemptyset(&sact.sa_mask);
	sact.sa_handler = sig;
	sigaction(SIGPIPE, &sact, NULL);
	sigaction(SIGCHLD, &sact, NULL);
	sigaction(SIGTERM, &sact, NULL);
	sigaction(SIGHUP, &sact, NULL);

	openlog("ansh3d", LOG_CONS | LOG_PID, LOG_DAEMON);

	if (Daemon) {
		switch (fork()) {
			case -1:
				ERR("Daemon mode #%d - %s\n", errno, strerror(errno));
				closelog();
				return 1;
			case 0:
				VERB(1) LOG("Welcome to dark ...\n");

				setsid();

				fd = open("/dev/null", O_WRONLY);
				if (fd) {
					dup2(fd, STDIN_FILENO);
					dup2(fd, STDOUT_FILENO);
					dup2(fd, STDERR_FILENO);
					if (fd > 2)
						close(fd);
				}
				break;
			default:
				VERB(1) LOG("Going to shadow land ...\n");
				closelog();
				return 0;
		}
	}

	if (ioCreatePIDFile(PIDFILE_ANSH3D, 42)) {
		ERR("Error:: already started ansh3d service ...\n");
		closelog();
		return 1;
	}

	h = PrepareL3(&sa, &bpfLEN);
	if (h == -1) {
		ERR("Error:: Descriptor not opened ... abort!\n");
		unlink(PIDFILE_ANSH3D);
		closelog();
		return 2;
	}

	SLIST_INIT(&pH);
	if (!(proc = InitProc(h, NULL, id, bpfLEN))) {
		ERR("Error:: Not enough memory ...\n");
		close(h);
		unlink(PIDFILE_ANSH3D);
		closelog();
		return 3;
	}

	root = schedBegin();
	if (!root) {
		ERR("Scheduler not init #%d - %s\n", sched_GetErrno(), sched_GetError());
		DestroyProc(id);
		close(h);
		unlink(PIDFILE_ANSH3D);
		closelog();
		return 4;
	} else
		root->root_hooks.hook_root.error = hook_error;

	chdir("/");
	chroot(szChroot);

	setgid(gid);
	setuid(uid);

	if (schedRead(root, icmpRx, (void*) id, h, NULL, 0)) {
		schedRun(root, &Kill);
	} else
		ERR("Failed to add reader task #%d - %s\n", sched_GetErrno(), sched_GetError());

	VERB(1) LOG("Finish process.");
	schedEnd(&root);
	DestroyProc(id);
	close(h);
	unlink(PIDFILE_ANSH3D);
	closelog();
	return 0;
}