/*	$NetBSD: scmio.c,v 1.5 1997/06/17 18:56:36 christos Exp $	*/

/*
 * Copyright (c) 1992 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software_Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 * SUP Communication Module for 4.3 BSD
 *
 * SUP COMMUNICATION MODULE SPECIFICATIONS:
 *
 * IN THIS MODULE:
 *
 * OUTPUT TO NETWORK
 *
 *   MESSAGE START/END
 *	writemsg (msg)		start message
 *	  int msg;			message type
 *	writemend ()		end message and flush data to network
 *
 *   MESSAGE DATA
 *	writeint (i)		write int
 *	  int i;			integer to write
 *	writestring (p)		write string
 *	  char *p;			string pointer
 *	writefile (f)		write open file
 *	  int f;			open file descriptor
 *
 *   COMPLETE MESSAGE (start, one data block, end)
 *	writemnull (msg)	write message with no data
 *	  int msg;			message type
 *	writemint (msg,i)	write int message
 *	  int msg;			message type
 *	  int i;			integer to write
 *	writemstr (msg,p)	write string message
 *	  int msg;			message type
 *	  char *p;			string pointer
 *
 * INPUT FROM NETWORK
 *   MESSAGE START/END
 *	readflush ()		flush any unread data (close)
 *	readmsg (msg)		read specified message type
 *	  int msg;			message type
 *	readmend ()		read message end
 *
 *   MESSAGE DATA
 *	readskip ()		skip over one input data block
 *	readint (i)		read int
 *	  int *i;			pointer to integer
 *	readstring (p)		read string
 *	  char **p;			pointer to string pointer
 *	readfile (f)		read into open file
 *	  int f;			open file descriptor
 *
 *   COMPLETE MESSAGE (start, one data block, end)
 *	readmnull (msg)		read message with no data
 *	  int msg;			message type
 *	readmint (msg,i)	read int message
 *	  int msg;			message type
 *	  int *i;			pointer to integer
 *	readmstr (msg,p)	read string message
 *	  int msg;			message type
 *	  char **p;			pointer to string pointer
 *
 * RETURN CODES
 *	All routines normally return SCMOK.  SCMERR may be returned
 *	by any routine on abnormal (usually fatal) errors.  An
 *	unexpected MSGGOAWAY will result in SCMEOF being returned.
 *
 * COMMUNICATION PROTOCOL
 *	Messages always alternate, with the first message after
 *	connecting being sent by the client process.
 *
 *	At the end of the conversation, the client process will
 *	send a message to the server telling it to go away.  Then,
 *	both processes will close the network connection.
 *
 *	Any time a process receives a message it does not expect,
 *	the "readmsg" routine will send a MSGGOAWAY message and
 *	return SCMEOF.
 *	
 *	Each message has this format:
 *	    ----------    ------------    ------------         ----------
 *	    |msg type|    |count|data|    |count|data|   ...   |ENDCOUNT|
 *	    ----------    ------------    ------------         ----------
 *	size:  int	    int  var.	    int  var.	   	  int
 *
 *	All ints are assumed to be 32-bit quantities.  A message
 *	with no data simply has a message type followed by ENDCOUNT.
 *
 **********************************************************************
 * HISTORY
 * Revision 1.7  92/09/09  22:04:41  mrt
 * 	Removed the data encryption routines from here to netcrypt.c
 * 	[92/09/09            mrt]
 * 
 * Revision 1.6  92/08/11  12:05:57  mrt
 * 	Brad's changes: Delinted,Added forward declarations of 
 * 	static functions. Added copyright.
 * 	[92/07/24            mrt]
 * 
 * 27-Dec-87  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Added crosspatch support.
 *
 * 28-Jun-87  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Found error in debuging code for readint().
 *
 * 01-Apr-87  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Added code to readdata to "push" data back into the data buffer.
 *	Added prereadcount() to return the message count size after
 *	reading it and then pushing it back into the buffer.  Clear
 *	any encryption when a GOAWAY message is detected before reading
 *	the reason string. [V5.19]
 *
 * 02-Oct-86  Rudy Nedved (ern) at Carnegie-Mellon University
 *	Put a timeout on reading from the network.
 *
 * 25-May-86  Jonathan J. Chew (jjc) at Carnegie-Mellon University
 *	Renamed "howmany" parameter to routines "encode" and "decode" from
 *	to "count" to avoid conflict with 4.3BSD macro.
 *
 * 15-Feb-86  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Added readflush() to flush any unread data from the input
 *	buffer.  Called by requestend() in scm.c module.
 *
 * 19-Jan-86  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Added register variables to decode() for speedup.  Added I/O
 *	buffering to reduce the number or read/write system calls.
 *	Removed readmfil/writemfil routines which were not used and were
 *	not compatable with the other similarly defined routines anyway.
 *
 * 19-Dec-85  Glenn Marcy (gm0w) at Carnegie-Mellon University
 *	Created from scm.c I/O and crypt routines.
 *
 **********************************************************************
 */

#include <libc.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/time.h>
#include "supcdefs.h"
#include "supextern.h"
#include "supmsg.h"

extern int errno;

/*************************
 ***    M A C R O S    ***
 *************************/

/* end of message */
#define ENDCOUNT (-1)			/* end of message marker */
#define NULLCOUNT (-2)			/* used for sending NULL pointer */

#define RETRIES 15			/* # of times to retry io */
#define FILEXFER 2048			/* block transfer size */
#define XFERSIZE(count) ((count > FILEXFER) ? FILEXFER : count)

/*********************************************
 ***    G L O B A L   V A R I A B L E S    ***
 *********************************************/

extern int netfile;			/* network file descriptor */

int scmdebug;				/* scm debug flag */

int cryptflag;				/* whether to encrypt/decrypt data */
char *cryptbuf;				/* buffer for data encryption/decryption */

extern char *goawayreason;		/* reason for goaway message */

struct buf {
	char b_data[FILEXFER];		/* buffered data */
	char *b_ptr;			/* pointer to end of buffer */
	int b_cnt;			/* number of bytes in buffer */
} buffers[2];
struct buf *bufptr;			/* buffer pointer */

static int writedata __P((int, char *));
static int writeblock __P((int, char *));
static int readdata __P((int, char *));
static int readcount __P((int *));


/***********************************************
 ***    O U T P U T   T O   N E T W O R K    ***
 ***********************************************/

static int
writedata (count,data)		/* write raw data to network */
int count;
char *data;
{
	register int x,tries;
	register struct buf *bp;

	if (bufptr) {
		if (bufptr->b_cnt + count <= FILEXFER) {
			bcopy (data,bufptr->b_ptr,count);
			bufptr->b_cnt += count;
			bufptr->b_ptr += count;
			return (SCMOK);
		}
		bp = (bufptr == buffers) ? &buffers[1] : buffers;
		bcopy (data,bp->b_data,count);
		bp->b_cnt = count;
		bp->b_ptr = bp->b_data + count;
		data = bufptr->b_data;
		count = bufptr->b_cnt;
		bufptr->b_cnt = 0;
		bufptr->b_ptr = bufptr->b_data;
		bufptr = bp;
	}
	tries = 0;
	for (;;) {
		errno = 0;
		x = write (netfile,data,count);
		if (x > 0)  break;
		if (errno)  break;
		if (++tries > RETRIES)  break;
		if (scmdebug > 0)
			logerr ("SCM Retrying failed network write");
	}
	if (x <= 0) {
		if (errno == EPIPE)
			return (scmerr (-1,"Network write timed out"));
		if (errno)
			return (scmerr (errno,"Write error on network"));
		return (scmerr (-1,"Write retries failed"));
	}
	if (x != count)
		return (scmerr (-1,"Write error on network returned %d on write of %d",x,count));
	return (SCMOK);
}

static int
writeblock (count,data)		/* write data block */
int count;
char *data;
{
	register int x;
	int y = byteswap(count);

	x = writedata (sizeof(int),(char *)&y);
	if (x == SCMOK)  x = writedata (count,data);
	return (x);
}

int
writemsg (msg)		/* write start of message */
int msg;
{
	int x;

	if (scmdebug > 1)
		loginfo ("SCM Writing message %d",msg);
	if (bufptr)
		return (scmerr (-1,"Buffering already enabled"));
	bufptr = buffers;
	bufptr->b_ptr = bufptr->b_data;
	bufptr->b_cnt = 0;
	x = byteswap (msg);
	return (writedata(sizeof(int),(char *)&x));
}

int
writemend ()		/* write end of message */
{
	register int count;
	register char *data;
	int x;

	x = byteswap (ENDCOUNT);
	x = writedata (sizeof(int),(char *)&x);
	if (x != SCMOK)  return (x);
	if (bufptr == NULL)
		return (scmerr (-1,"Buffering already disabled"));
	if (bufptr->b_cnt == 0) {
		bufptr = NULL;
		return (SCMOK);
	}
	data = bufptr->b_data;
	count = bufptr->b_cnt;
	bufptr = NULL;
	return (writedata (count, data));
}

int
writeint (i)		/* write int as data block */
int i;
{
	int x;
	if (scmdebug > 2)
		loginfo ("SCM Writing integer %d",i);
	x = byteswap(i);
	return (writeblock(sizeof(int),(char *)&x));
}

int
writestring (p)		/* write string as data block */
char *p;
{
	register int len,x;
	if (p == NULL) {
		int y = byteswap(NULLCOUNT);
		if (scmdebug > 2)
			loginfo ("SCM Writing string NULL");
		return (writedata (sizeof(int),(char *)&y));
	}
	if (scmdebug > 2)
		loginfo ("SCM Writing string %s",p);
	len = strlen (p);
	if (cryptflag) {
		x = getcryptbuf (len+1);
		if (x != SCMOK)
			return (x);
		encode (p,cryptbuf,len);
		p = cryptbuf;
	}
	return (writeblock(len,p));
}

int
writefile (f)		/* write open file as a data block */
int f;
{
	char buf[FILEXFER];
	register int number = 0,sum = 0,filesize,x;
	int y;
	struct stat statbuf;

	if (fstat(f,&statbuf) < 0)
		return (scmerr (errno,"Can't access open file for message"));
	filesize = statbuf.st_size;
	y = byteswap(filesize);
	x = writedata (sizeof(int),(char *)&y);

	if (cryptflag)  x = getcryptbuf (FILEXFER);

	if (x == SCMOK) {
		sum = 0;
		do {
			number = read (f,buf,FILEXFER);
			if (number > 0) {
				if (cryptflag) {
					encode (buf,cryptbuf,number);
					x = writedata (number,cryptbuf);
				}
				else {
					x = writedata (number,buf);
				}
				sum += number;
			}
		} while (x == SCMOK && number > 0);
	}
	if (sum != filesize)
		return (scmerr (-1,"File size error on output message"));
	if (number < 0)
		return (scmerr (errno,"Read error on file output message"));
	return (x);
}

int
writemnull (msg)	/* write message with no data */
int msg;
{
	register int x;
	x = writemsg (msg);
	if (x == SCMOK)  x = writemend ();
	return (x);
}

int
writemint (msg,i)		/* write message of one int */
int msg,i;
{
	register int x;
	x = writemsg (msg);
	if (x == SCMOK)  x = writeint (i);
	if (x == SCMOK)  x = writemend ();
	return (x);
}

int
writemstr (msg,p)		/* write message of one string */
int msg;
char *p;
{
	register int x;
	x = writemsg (msg);
	if (x == SCMOK)  x = writestring (p);
	if (x == SCMOK)  x = writemend ();
	return (x);
}

/*************************************************
 ***    I N P U T   F R O M   N E T W O R K    ***
 *************************************************/

static int
readdata (count,data)		/* read raw data from network */
int count;
char *data;
{
	register char *p;
	register int n,m,x;
	int tries;
	static int bufcnt = 0;
	static char *bufptr;
	static char buffer[FILEXFER];
	static int imask;
	static struct timeval timout;

	if (count < 0) {
		if (bufptr + count < buffer)
			return (scmerr (-1,"No space in buffer %d",count));
		bufptr += count;
		bufcnt -= count;
		bcopy (data,bufptr,-count);
		return (SCMOK);
	}
	if (count == 0 && data == NULL) {
		bufcnt = 0;
		return (SCMOK);
	}
	if (count <= bufcnt) {
		bcopy (bufptr,data,count);
		bufptr += count;
		bufcnt -= count;
		return (SCMOK);
	}
	if (bufcnt > 0) {
		bcopy (bufptr,data,bufcnt);
		data += bufcnt;
		count -= bufcnt;
	}
	bufptr = buffer;
	bufcnt = 0;
	timout.tv_usec = 0;
	timout.tv_sec = 2*60*60;
	p = buffer;
	n = FILEXFER;
	m = count;
	while (m > 0) {
		tries = 0;
		for (;;) {
			imask = 1 << netfile;
			if (select(32,(fd_set *)&imask,(fd_set *)0,(fd_set *)0,&timout) < 0)
				imask = 1;
			errno = 0;
			if (imask)
				x = read (netfile,p,n);
			else
				return (scmerr (-1,"Timeout on network input"));
			if (x > 0)  break;
			if (x == 0)
				return (scmerr (-1,"Premature EOF on network input"));
			if (errno)  break;
			if (++tries > RETRIES)  break;
			if (scmdebug > 0)
				loginfo ("SCM Retrying failed network read");
		}
		if (x < 0) {
			if (errno)
				return (scmerr (errno,"Read error on network"));
			return (scmerr (-1,"Read retries failed"));
		}
		p += x;
		n -= x;
		m -= x;
		bufcnt += x;
	}
	bcopy (bufptr,data,count);
	bufptr += count;
	bufcnt -= count;
	return (SCMOK);
}

static
int readcount (count)			/* read count of data block */
int *count;
{
	register int x;
	int y;
	x = readdata (sizeof(int),(char *)&y);
	if (x != SCMOK)  return (x);
	*count = byteswap(y);
	return (SCMOK);
}

int prereadcount (count)		/* preread count of data block */
int *count;
{
	register int x;
	int y;
	x = readdata (sizeof(int),(char *)&y);
	if (x != SCMOK)  return (x);
	x = readdata (- ((int)(sizeof(int))),(char *)&y);
	if (x != SCMOK)  return (x);
	*count = byteswap(y);
	return (SCMOK);
}

int
readflush ()
{
	return (readdata (0, (char *)NULL));
}

int
readmsg (msg)		/* read header for expected message */
int msg;		/* if message is unexpected, send back SCMHUH */
{
	register int x;
	int m;
	if (scmdebug > 1)
		loginfo ("SCM Reading message %d",msg);
	x = readdata (sizeof(int),(char *)&m);	/* msg type */
	if (x != SCMOK)  return (x);
	m = byteswap(m);
	if (m == msg)  return (x);

	/* check for MSGGOAWAY in case he noticed problems first */
	if (m != MSGGOAWAY)
		return (scmerr (-1,"Received unexpected message %d",m));
	(void) netcrypt ((char *)NULL);
	(void) readstring (&goawayreason);
	(void) readmend ();
	if (goawayreason == NULL)
		return (SCMEOF);
	logerr ("SCM GOAWAY %s",goawayreason);
	return (SCMEOF);
}

int
readmend ()
{
	register int x;
	int y;
	x = readdata (sizeof(int),(char *)&y);
	y = byteswap(y);
	if (x == SCMOK && y != ENDCOUNT)
		return (scmerr (-1,"Error reading end of message"));
	return (x);
}

int
readskip ()			/* skip over one input block */
{
	register int x;
	int n;
	char buf[FILEXFER];
	x = readcount (&n);
	if (x != SCMOK)  return (x);
	if (n < 0)
		return (scmerr (-1,"Invalid message count %d",n));
	while (x == SCMOK && n > 0) {
		x = readdata (XFERSIZE(n),buf);
		n -= XFERSIZE(n);
	}
	return (x);
}

int readint (buf)		/* read int data block */
int *buf;
{
	register int x;
	int y;
	x = readcount (&y);
	if (x != SCMOK)  return (x);
	if (y < 0)
		return (scmerr (-1,"Invalid message count %d",y));
	if (y != sizeof(int))
		return (scmerr (-1,"Size error for int message is %d",y));
	x = readdata (sizeof(int),(char *)&y);
	(*buf) = byteswap(y);
	if (scmdebug > 2)
		loginfo ("SCM Reading integer %d",*buf);
	return (x);
}

int readstring (buf)	/* read string data block */
register char **buf;
{
	register int x;
	int count;
	register char *p;

	x = readcount (&count);
	if (x != SCMOK)  return (x);
	if (count == NULLCOUNT) {
		if (scmdebug > 2)
			loginfo ("SCM Reading string NULL");
		*buf = NULL;
		return (SCMOK);
	}
	if (count < 0)
		return (scmerr (-1,"Invalid message count %d",count));
	if (scmdebug > 3)
		loginfo ("SCM Reading string count %d",count);
	if ((p = (char *)malloc ((unsigned)count+1)) == NULL)
		return (scmerr (-1,"Can't malloc %d bytes for string",count));
	if (cryptflag) {
		x = getcryptbuf (count+1);
		if (x == SCMOK)  x = readdata (count,cryptbuf);
		if (x != SCMOK)  return (x);
	if (scmdebug > 3)
		printf ("SCM Reading encrypted string %s\n",cryptbuf);
		decode (cryptbuf,p,count);
	}
	else {
		x = readdata (count,p);
		if (x != SCMOK)  return (x);
	}
	p[count] = 0;		/* NULL at end of string */
	*buf = p;
	if (scmdebug > 2)
		loginfo ("SCM Reading string %s",*buf);
	return (SCMOK);
}

int
readfile (f)		/* read data block into open file */
int f;
{
	register int x;
	int count;
	char buf[FILEXFER];

	if (cryptflag) {
		x = getcryptbuf (FILEXFER);
		if (x != SCMOK)  return (x);
	}
	x = readcount (&count);
	if (x != SCMOK)  return (x);
	if (count < 0)
		return (scmerr (-1,"Invalid message count %d",count));
	while (x == SCMOK && count > 0) {
		if (cryptflag) {
			x = readdata (XFERSIZE(count),cryptbuf);
			if (x == SCMOK)  decode (cryptbuf,buf,XFERSIZE(count));
		}
		else
			x = readdata (XFERSIZE(count),buf);
		if (x == SCMOK) {
			(void) write (f,buf,XFERSIZE(count));
			count -= XFERSIZE(count);
		}
	}
	return (x);
}

int
readmnull (msg)		/* read null message */
int msg;
{
	register int x;
	x = readmsg (msg);
	if (x == SCMOK)  x = readmend ();
	return (x);
}

int
readmint (msg,buf)		/* read int message */
int msg,*buf;
{
	register int x;
	x = readmsg (msg);
	if (x == SCMOK)  x = readint (buf);
	if (x == SCMOK)  x = readmend ();
	return (x);
}

int readmstr (msg,buf)		/* read string message */
int msg;
char **buf;
{
	register int x;
	x = readmsg (msg);
	if (x == SCMOK)  x = readstring (buf);
	if (x == SCMOK)  x = readmend ();
	return (x);
}

/**********************************
 ***    C R O S S P A T C H     ***
 **********************************/

void
crosspatch ()
{
	fd_set ibits, obits, xbits;
	register int c;
	char buf[STRINGLENGTH];

	for (;;) {
		FD_ZERO (&ibits);
		FD_ZERO (&obits);
		FD_ZERO (&xbits);
		FD_SET (0,&ibits);
		FD_SET (netfile,&ibits);
		if ((c = select(16, &ibits, &obits, &xbits,
				(struct timeval *)NULL)) < 1) {
			if (c == -1) {
				if (errno == EINTR) {
					continue;
				}
			}
			sleep (5);
			continue;
		}
		if (FD_ISSET (netfile,&ibits)) {
			c = read (netfile,buf,sizeof (buf));
			if (c < 0 && errno == EWOULDBLOCK)
				c = 0;
			else {
				if (c <= 0) {
					break;
				}
				(void) write (1,buf,c);
			}
		}
		if (FD_ISSET(0, &ibits)) {
			c = read (0,buf,sizeof (buf));
			if (c < 0 && errno == EWOULDBLOCK)
				c = 0;
			else {
				if (c <= 0)
					break;
				(void) write (netfile,buf,c);
			}
		}
	}
}