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/* slip.c SLIP interface unit
*
* $Id: slip.c,v 1.11 1995/03/19 17:21:06 bdale Exp $
*
* Copyright 1991, Michael Westerhof, Sun Microsystems, Inc.
* This software may be freely used, distributed, or modified, providing
* this header is not removed.
*/
#include "ipip.h"
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netdb.h>
#include <fcntl.h>
#include <memory.h>
#include <stdio.h>
#include <string.h>
#ifdef __bsdi__
# include <stdlib.h>
#else
# include <malloc.h>
#endif
#include <errno.h>
#include <syslog.h>
#ifdef __bsdi__
#define USE_TERMIOS
#endif
#ifndef USE_TERMIOS
#ifndef USE_TERMIO
#define USE_SGTTY
#endif
#endif
#ifdef USE_TERMIOS
# include <termios.h>
# include <unistd.h>
#endif
#ifdef USE_TERMIO
#include <sys/termio.h>
#endif
#ifdef USE_SGTTY
#include <sgtty.h>
#endif
#ifndef FNDELAY
#define FNDELAY O_NDELAY
#endif
extern int errno;
#define IF_NAME "slip" /* for use with the error checking macros */
/*
* Define the special characters used by SLIP
*/
#define FEND 0xc0
#define FESC 0xdb
#define TFEND 0xdc
#define TFESC 0xdd
/*
* This is the routine that assembles a slip packet, and the private
* data structure we need to keep track of where we are.
*/
static int assemble_slip();
struct slippy {
unsigned char buffer[MAX_SIZE]; /* buffer from the serial line */
int bcount; /* number of total chars in buffer */
int bnext; /* next character to process */
unsigned char ipacket[MAX_SIZE]; /* the packet we are assembling */
int ifcount; /* total size of assembled packet */
int iescaped; /* flag set if we are escaped */
};
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* open and initialize the IO interface. Return -1 for error.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
int slip_open(ifp)
struct interface *ifp;
{
int baudrate;
#ifdef USE_TERMIOS
struct termios nterm;
#endif
#ifdef USE_TERMIO
struct termio nterm;
#endif
#ifdef USE_SGTTY
struct sgttyb nterm;
#endif
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_SLIP);
if((ifp->status & IF_STAT_OPEN)) return 1;
#ifdef __bsdi__
/* BSDI cares about the modem control lines, so this won't ever
come back unless we do the open non-blocking, then set CLOCAL. */
ifp->fd = open(ifp->devname, O_RDWR | O_NONBLOCK);
#else
ifp->fd = open(ifp->devname, O_RDWR);
#endif
if (ifp->fd<0) {
PERR(ifp->devname);
return -1;
}
if (fcntl(ifp->fd, F_SETFL, FNDELAY) < 0) {
PERR("setting non-blocking I/O on tty device");
return -1;
}
#ifdef USE_TERMIOS
#if defined(__bsdi__) || defined(linux)
if(tcgetattr(ifp->fd, &nterm)<0){
#else
if(ioctl(ifp->fd, TCGETS, &nterm)<0){
#endif /* __bsdi__ */
#endif
#ifdef USE_TERMIO
if(ioctl(ifp->fd, TCGETA, &nterm)<0){
#endif
#ifdef USE_SGTTY
if(ioctl(ifp->fd, TIOCGETP, &nterm)<0){
#endif
PERR("fetching tty device parameters");
return -1;
}
if(ifp->unit==50)baudrate=B50;
else if(ifp->unit==50)baudrate=B50;
else if(ifp->unit==75)baudrate=B75;
else if(ifp->unit==110)baudrate=B110;
else if(ifp->unit==134)baudrate=B134;
else if(ifp->unit==150)baudrate=B150;
else if(ifp->unit==200)baudrate=B200;
else if(ifp->unit==300)baudrate=B300;
else if(ifp->unit==600)baudrate=B600;
else if(ifp->unit==1200)baudrate=B1200;
else if(ifp->unit==1800)baudrate=B1800;
else if(ifp->unit==2400)baudrate=B2400;
else if(ifp->unit==4800)baudrate=B4800;
else if(ifp->unit==9600)baudrate=B9600;
#ifdef B19200
else if(ifp->unit==19200)baudrate=B19200;
#else
#ifdef EXTA
else if(ifp->unit==19200)baudrate=EXTA;
#endif
#endif
#ifdef B38400
else if(ifp->unit==38400)baudrate=B38400;
#else
#ifdef EXTB
else if(ifp->unit==38400)baudrate=EXTB;
#endif
#endif
else baudrate = B9600;
#ifdef USE_SGTTY
nterm.sg_flags = (RAW | ANYP);
nterm.sg_ispeed = baudrate;
nterm.sg_ospeed = baudrate;
#else
nterm.c_iflag = 0;
nterm.c_oflag = 0;
nterm.c_cflag = baudrate | CS8 | CREAD | CLOCAL;
nterm.c_lflag = 0;
nterm.c_cc[VMIN] = 0;
nterm.c_cc[VTIME] = 0;
#endif
#ifdef USE_TERMIOS
#if defined(__bsdi__) || defined(linux)
if(tcsetattr(ifp->fd, TCSANOW, &nterm)<0){
#else
if(ioctl(ifp->fd, TCSETS, &nterm)<0){
#endif /* __bsdi__ */
#endif
#ifdef USE_TERMIO
if(ioctl(ifp->fd, TCSETA, &nterm)<0){
#endif
#ifdef USE_SGTTY
if(ioctl(ifp->fd, TIOCSETP, &nterm)<0){
#endif
PERR("setting tty device parameters");
return -1;
}
if(ifp->private==NULL)ifp->private = malloc(sizeof(struct slippy));
if(ifp->private==NULL){
syslog(LOG_ERR,"cannot allocate private data structure (slip)");
return -1;
}
(void)memset(ifp->private, 0, sizeof(struct slippy));
ifp->status = IF_STAT_OPEN;
return 1;
}
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Read data from the specified interface. Return a complete IP datagram.
* If the datagram is not complete, then don't return anything.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
int slip_read(ifp, m)
struct interface *ifp;
struct message *m;
{
int n;
struct slippy *s;
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_SLIP);
CK_IFOPEN(ifp);
CK_MNULL(m);
s = (struct slippy *)ifp->private;
ifp->status &= ~IF_STAT_CALL_AGAIN;
m->length = 0;
for(;;){
if(s->bnext >= s->bcount){ /* we need more data! */
s->bnext = 0;
s->bcount = 0;
n = read(ifp->fd, (char *)s->buffer, MAX_SIZE);
if(n==0)return 0; /* got nothing */
if(n<0){
if(errno==EINTR)return 0; /* SIGHUP! */
if(errno==EWOULDBLOCK)return 0; /* got nothing */
PERR("read from tty device");
return -1;
}
s->bcount = n;
}
n = assemble_slip(s, s->buffer[s->bnext]);
s->bnext++;
if(n > 0){
(void)memcpy((char *)m->msg, (char *)s->ipacket, n);
m->length = n;
if(s->bnext < s->bcount)
ifp->status |= IF_STAT_CALL_AGAIN;
return n;
}
}
}
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* write data from to the specified interface. Return as soon as possible.
* The buffer provided will be a complete IP datagram.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
#define SLIPEMIT(x) if(ofcount<MAX_SIZE*2){*ofptr=(x);ofptr++;ofcount++;}
int slip_send(ifp, m)
struct interface *ifp;
struct message *m;
{
int n, i, ofcount;
unsigned char opacket[MAX_SIZE*2], *ofptr, *mptr;
CK_IFNULL(ifp);
CK_IFTYPE(ifp,IF_TYPE_SLIP);
CK_IFOPEN(ifp);
CK_MNULL(m);
if(m->length<=0)return 0;
ofptr = opacket;
ofcount = 0;
mptr = m->msg;
SLIPEMIT(FEND);
for(i=0;i<m->length;i++,mptr++){
if(*mptr==FEND){
SLIPEMIT(FESC);
SLIPEMIT(TFEND);
}else if (*mptr==FESC){
SLIPEMIT(FESC);
SLIPEMIT(TFESC);
}else {
SLIPEMIT(*mptr);
}
}
SLIPEMIT(FEND);
/*
* WARNING! It is possible for this write to actually write less data
* than expected if the system has, for example, no buffer space left.
* We ignore the error (just increment the write overrun counter),
* drop the current packet, and expect that the higher level protocols
* will recover.
*
* If we got an "interrupted system call" error we print the diagnostic
* and continue. (the packet gets dropped as above).
*/
n = write(ifp->fd, (char *)opacket, ofcount);
if(n<0){
syslog(LOG_ERR,"slip_send(): %s",strerror(errno));
if((errno==EINTR) || (errno==EAGAIN)) return 0;
return -1;
}
if(n < ofcount)ifp->out_overruns++;
return n;
}
/*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* take a character and assemble it into the buffer. Return the length
* of the completed packet, 0 if not yet completed. Packet can be found
* in the private buffer...
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*/
static int
assemble_slip(s, c)
struct slippy *s;
unsigned char c;
{
int n;
if(c==FEND){
n = s->ifcount;
s->ifcount = 0;
s->iescaped = 0;
return n;
}
if(c==FESC){
s->iescaped=1;
return 0;
}
if(s->iescaped){
if(c==TFEND)c = FEND;
if(c==TFESC)c = FESC;
s->iescaped = 0;
}
if(s->ifcount < MAX_SIZE){
s->ipacket[s->ifcount] = c;
s->ifcount++;
}
return 0;
}
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