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/*
* PPP Async HDLC Module
*
* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
*
* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the Internet Initiative Japan, Inc. The name of the
* IIJ 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 WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: async.c,v 1.4 1995/05/30 03:50:24 rgrimes Exp $
*
*/
#include "fsm.h"
#include "hdlc.h"
#include "lcp.h"
#include "lcpproto.h"
#include "modem.h"
#include "vars.h"
#include "os.h"
#define HDLCSIZE (MAX_MRU*2+6)
struct async_state {
int mode;
int length;
u_char hbuff[HDLCSIZE]; /* recv buffer */
u_char xbuff[HDLCSIZE]; /* xmit buffer */
u_long my_accmap;
u_long his_accmap;
} AsyncState;
#define MODE_HUNT 0x01
#define MODE_ESC 0x02
void
AsyncInit()
{
struct async_state *stp = &AsyncState;
stp->mode = MODE_HUNT;
stp->length = 0;
stp->my_accmap = stp->his_accmap = 0xffffffff;
}
void
SetLinkParams(lcp)
struct lcpstate *lcp;
{
struct async_state *stp = &AsyncState;
stp->my_accmap = lcp->want_accmap;
stp->his_accmap = lcp->his_accmap;
}
/*
* Encode into async HDLC byte code if necessary
*/
static void
HdlcPutByte(cp, c, proto)
u_char **cp;
u_char c;
int proto;
{
u_char *wp;
wp = *cp;
if ((c < 0x20 && (proto == PROTO_LCP || (AsyncState.his_accmap & (1<<c))))
|| (c == HDLC_ESC) || (c == HDLC_SYN)) {
*wp++ = HDLC_ESC;
c ^= HDLC_XOR;
}
if (EscMap[32] && EscMap[c >> 3] & (1 << (c&7))) {
*wp++ = HDLC_ESC;
c ^= HDLC_XOR;
}
*wp++ = c;
*cp = wp;
}
void
AsyncOutput(pri, bp, proto)
int pri;
struct mbuf *bp;
int proto;
{
struct async_state *hs = &AsyncState;
u_char *cp, *sp, *ep;
struct mbuf *wp;
int cnt;
if (plength(bp) > HDLCSIZE) {
pfree(bp);
return;
}
cp = hs->xbuff;
ep = cp + HDLCSIZE - 10;
wp = bp;
*cp ++ = HDLC_SYN;
while (wp) {
sp = MBUF_CTOP(wp);
for (cnt = wp->cnt; cnt > 0; cnt--) {
HdlcPutByte(&cp, *sp++, proto);
if (cp >= ep) {
pfree(bp);
return;
}
}
wp = wp->next;
}
*cp ++ = HDLC_SYN;
cnt = cp - hs->xbuff;
LogDumpBuff(LOG_ASYNC, "WriteModem", hs->xbuff, cnt);
WriteModem(pri, (char *)hs->xbuff, cnt);
OsAddOutOctets(cnt);
pfree(bp);
}
struct mbuf *
AsyncDecode(c)
u_char c;
{
struct async_state *hs = &AsyncState;
struct mbuf *bp;
if ((hs->mode & MODE_HUNT) && c != HDLC_SYN)
return(NULLBUFF);
switch (c) {
case HDLC_SYN:
hs->mode &= ~MODE_HUNT;
if (hs->length) { /* packet is ready. */
bp = mballoc(hs->length, MB_ASYNC);
mbwrite(bp, hs->hbuff, hs->length);
hs->length = 0;
return(bp);
}
break;
case HDLC_ESC:
if (!(hs->mode & MODE_ESC)) {
hs->mode |= MODE_ESC;
break;
}
/* Fall into ... */
default:
if (hs->length >= HDLCSIZE) {
/* packet is too large, discard it */
logprintf("too large, diacarding.\n");
hs->length = 0;
hs->mode = MODE_HUNT;
break;
}
if (hs->mode & MODE_ESC) {
c ^= HDLC_XOR;
hs->mode &= ~MODE_ESC;
}
hs->hbuff[hs->length++] = c;
break;
}
return NULLBUFF;
}
void
AsyncInput(buff, cnt)
u_char *buff;
int cnt;
{
struct mbuf *bp;
OsAddInOctets(cnt);
if (DEV_IS_SYNC) {
bp = mballoc(cnt, MB_ASYNC);
bcopy(buff, MBUF_CTOP(bp), cnt);
bp->cnt = cnt;
HdlcInput(bp);
} else {
while (cnt > 0) {
bp = AsyncDecode(*buff++);
if (bp)
HdlcInput(bp);
cnt--;
}
}
}
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