/*
 * Dropbear - a SSH2 server
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * strlcat() is copyright as follows:
 * Copyright (c) 1998 Todd C. Miller <[email protected]>
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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 "includes.h"
#include "dbutil.h"
#include "buffer.h"
#include "session.h"
#include "atomicio.h"

#define MAX_FMT 100

static void generic_dropbear_exit(int exitcode, const char* format, 
		va_list param) ATTRIB_NORETURN;
static void generic_dropbear_log(int priority, const char* format, 
		va_list param);

void (*_dropbear_exit)(int exitcode, const char* format, va_list param) ATTRIB_NORETURN
						= generic_dropbear_exit;
void (*_dropbear_log)(int priority, const char* format, va_list param)
						= generic_dropbear_log;

#ifdef DEBUG_TRACE
int debug_trace = 0;
#endif

#ifndef DISABLE_SYSLOG
void startsyslog() {

	openlog(PROGNAME, LOG_PID, LOG_AUTHPRIV);

}
#endif /* DISABLE_SYSLOG */

/* the "format" string must be <= 100 characters */
void dropbear_close(const char* format, ...) {

	va_list param;

	va_start(param, format);
	_dropbear_exit(EXIT_SUCCESS, format, param);
	va_end(param);

}

void dropbear_exit(const char* format, ...) {

	va_list param;

	va_start(param, format);
	_dropbear_exit(EXIT_FAILURE, format, param);
	va_end(param);
}

static void generic_dropbear_exit(int exitcode, const char* format, 
		va_list param) {

	char fmtbuf[300];

	snprintf(fmtbuf, sizeof(fmtbuf), "Exited: %s", format);

	_dropbear_log(LOG_INFO, fmtbuf, param);

	exit(exitcode);
}

void fail_assert(const char* expr, const char* file, int line) {
	dropbear_exit("Failed assertion (%s:%d): `%s'", file, line, expr);
}

static void generic_dropbear_log(int UNUSED(priority), const char* format, 
		va_list param) {

	char printbuf[1024];

	vsnprintf(printbuf, sizeof(printbuf), format, param);

	fprintf(stderr, "%s\n", printbuf);

}

/* this is what can be called to write arbitrary log messages */
void dropbear_log(int priority, const char* format, ...) {

	va_list param;

	va_start(param, format);
	_dropbear_log(priority, format, param);
	va_end(param);
}


#ifdef DEBUG_TRACE
void dropbear_trace(const char* format, ...) {

	va_list param;

	if (!debug_trace) {
		return;
	}

	va_start(param, format);
	fprintf(stderr, "TRACE (%d): ", getpid());
	vfprintf(stderr, format, param);
	fprintf(stderr, "\n");
	va_end(param);
}
#endif /* DEBUG_TRACE */

static void set_sock_priority(int sock) {

	int val;

	/* disable nagle */
	val = 1;
	setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void*)&val, sizeof(val));

	/* set the TOS bit for either ipv4 or ipv6 */
#ifdef IPTOS_LOWDELAY
	val = IPTOS_LOWDELAY;
#if defined(IPPROTO_IPV6) && defined(IPV6_TCLASS)
	setsockopt(sock, IPPROTO_IPV6, IPV6_TCLASS, (void*)&val, sizeof(val));
#endif
	setsockopt(sock, IPPROTO_IP, IP_TOS, (void*)&val, sizeof(val));
#endif

#ifdef SO_PRIORITY
	/* linux specific, sets QoS class.
	 * 6 looks to be optimal for interactive traffic (see tc-prio(8) ). */
	val = 6;
	setsockopt(sock, SOL_SOCKET, SO_PRIORITY, (void*) &val, sizeof(val));
#endif

}

/* Listen on address:port. 
 * Special cases are address of "" listening on everything,
 * and address of NULL listening on localhost only.
 * Returns the number of sockets bound on success, or -1 on failure. On
 * failure, if errstring wasn't NULL, it'll be a newly malloced error
 * string.*/
int dropbear_listen(const char* address, const char* port,
		int *socks, unsigned int sockcount, char **errstring, int *maxfd) {

	struct addrinfo hints, *res = NULL, *res0 = NULL;
	int err;
	unsigned int nsock;
	struct linger linger;
	int val;
	int sock;

	TRACE(("enter dropbear_listen"))
	
	memset(&hints, 0, sizeof(hints));
	hints.ai_family = AF_UNSPEC; /* TODO: let them flag v4 only etc */
	hints.ai_socktype = SOCK_STREAM;

	/* for calling getaddrinfo:
	 address == NULL and !AI_PASSIVE: local loopback
	 address == NULL and AI_PASSIVE: all interfaces
	 address != NULL: whatever the address says */
	if (!address) {
		TRACE(("dropbear_listen: local loopback"))
	} else {
		if (address[0] == '\0') {
			TRACE(("dropbear_listen: all interfaces"))
			address = NULL;
		}
		hints.ai_flags = AI_PASSIVE;
	}
	err = getaddrinfo(address, port, &hints, &res0);

	if (err) {
		if (errstring != NULL && *errstring == NULL) {
			int len;
			len = 20 + strlen(gai_strerror(err));
			*errstring = (char*)m_malloc(len);
			snprintf(*errstring, len, "Error resolving: %s", gai_strerror(err));
		}
		if (res0) {
			freeaddrinfo(res0);
			res0 = NULL;
		}
		TRACE(("leave dropbear_listen: failed resolving"))
		return -1;
	}


	nsock = 0;
	for (res = res0; res != NULL && nsock < sockcount;
			res = res->ai_next) {

		/* Get a socket */
		socks[nsock] = socket(res->ai_family, res->ai_socktype,
				res->ai_protocol);

		sock = socks[nsock]; /* For clarity */

		if (sock < 0) {
			err = errno;
			TRACE(("socket() failed"))
			continue;
		}

		/* Various useful socket options */
		val = 1;
		/* set to reuse, quick timeout */
		setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &val, sizeof(val));
		linger.l_onoff = 1;
		linger.l_linger = 5;
		setsockopt(sock, SOL_SOCKET, SO_LINGER, (void*)&linger, sizeof(linger));

#if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
		if (res->ai_family == AF_INET6) {
			int on = 1;
			if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, 
						&on, sizeof(on)) == -1) {
				dropbear_log(LOG_WARNING, "Couldn't set IPV6_V6ONLY");
			}
		}
#endif

		set_sock_priority(sock);

		if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
			err = errno;
			close(sock);
			TRACE(("bind(%s) failed", port))
			continue;
		}

		if (listen(sock, 20) < 0) {
			err = errno;
			close(sock);
			TRACE(("listen() failed"))
			continue;
		}

		*maxfd = MAX(*maxfd, sock);

		nsock++;
	}

	if (res0) {
		freeaddrinfo(res0);
		res0 = NULL;
	}

	if (nsock == 0) {
		if (errstring != NULL && *errstring == NULL) {
			int len;
			len = 20 + strlen(strerror(err));
			*errstring = (char*)m_malloc(len);
			snprintf(*errstring, len, "Error listening: %s", strerror(err));
		}
		TRACE(("leave dropbear_listen: failure, %s", strerror(err)))
		return -1;
	}

	TRACE(("leave dropbear_listen: success, %d socks bound", nsock))
	return nsock;
}

/* Connect to a given unix socket. The socket is blocking */
#ifdef ENABLE_CONNECT_UNIX
int connect_unix(const char* path) {
	struct sockaddr_un addr;
	int fd = -1;

	memset((void*)&addr, 0x0, sizeof(addr));
	addr.sun_family = AF_UNIX;
	strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
	fd = socket(PF_UNIX, SOCK_STREAM, 0);
	if (fd < 0) {
		TRACE(("Failed to open unix socket"))
		return -1;
	}
	if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
		TRACE(("Failed to connect to '%s' socket", path))
		m_close(fd);
		return -1;
	}
	return fd;
}
#endif

/* Connect via TCP to a host. Connection will try ipv4 or ipv6, will
 * return immediately if nonblocking is set. On failure, if errstring
 * wasn't null, it will be a newly malloced error message */

/* TODO: maxfd */
int connect_remote(const char* remotehost, const char* remoteport,
		int nonblocking, char ** errstring) {

	struct addrinfo *res0 = NULL, *res = NULL, hints;
	int sock;
	int err;

	TRACE(("enter connect_remote"))

	if (errstring != NULL) {
		*errstring = NULL;
	}

	memset(&hints, 0, sizeof(hints));
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_family = PF_UNSPEC;

	err = getaddrinfo(remotehost, remoteport, &hints, &res0);
	if (err) {
		if (errstring != NULL && *errstring == NULL) {
			int len;
			len = 100 + strlen(gai_strerror(err));
			*errstring = (char*)m_malloc(len);
			snprintf(*errstring, len, "Error resolving '%s' port '%s'. %s", 
					remotehost, remoteport, gai_strerror(err));
		}
		TRACE(("Error resolving: %s", gai_strerror(err)))
		return -1;
	}

	sock = -1;
	err = EADDRNOTAVAIL;
	for (res = res0; res; res = res->ai_next) {

		sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
		if (sock < 0) {
			err = errno;
			continue;
		}

		if (nonblocking) {
			setnonblocking(sock);