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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.
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <string.h>
#include <termios.h>
#include "layer.h"
#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "timer.h"
#include "fsm.h"
#include "lqr.h"
#include "hdlc.h"
#include "lcp.h"
#include "proto.h"
#include "async.h"
#include "throughput.h"
#include "ccp.h"
#include "link.h"
#include "descriptor.h"
#include "physical.h"
#define MODE_HUNT 0x01
#define MODE_ESC 0x02
void
async_Init(struct async *async)
{
async->mode = MODE_HUNT;
async->length = 0;
async->my_accmap = async->his_accmap = 0xffffffff;
memset(async->cfg.EscMap, '\0', sizeof async->cfg.EscMap);
}
void
async_SetLinkParams(struct async *async, struct lcp *lcp)
{
async->my_accmap = lcp->want_accmap;
async->his_accmap = lcp->his_accmap | lcp->want_accmap;
}
/*
* Encode into async HDLC byte code
*/
static void
async_Encode(struct async *async, u_char **cp, u_char c, int proto)
{
u_char *wp;
wp = *cp;
if ((c < 0x20 && (proto == PROTO_LCP || (async->his_accmap & (1 << c))))
|| (c == HDLC_ESC) || (c == HDLC_SYN)) {
*wp++ = HDLC_ESC;
c ^= HDLC_XOR;
}
if (async->cfg.EscMap[32] && async->cfg.EscMap[c >> 3] & (1 << (c & 7))) {
*wp++ = HDLC_ESC;
c ^= HDLC_XOR;
}
*wp++ = c;
*cp = wp;
}
static struct mbuf *
async_LayerPush(struct bundle *bundle, struct link *l, struct mbuf *bp,
int pri, u_short *proto)
{
struct physical *p = link2physical(l);
u_char *cp, *sp, *ep;
struct mbuf *wp;
int cnt;
if (!p || mbuf_Length(bp) > HDLCSIZE) {
mbuf_Free(bp);
return NULL;
}
cp = p->async.xbuff;
ep = cp + HDLCSIZE - 10;
wp = bp;
*cp++ = HDLC_SYN;
while (wp) {
sp = MBUF_CTOP(wp);
for (cnt = wp->cnt; cnt > 0; cnt--) {
async_Encode(&p->async, &cp, *sp++, *proto);
if (cp >= ep) {
mbuf_Free(bp);
return NULL;
}
}
wp = wp->next;
}
*cp++ = HDLC_SYN;
cnt = cp - p->async.xbuff;
mbuf_Free(bp);
bp = mbuf_Alloc(cnt, MB_ASYNCOUT);
memcpy(MBUF_CTOP(bp), p->async.xbuff, cnt);
log_DumpBp(LogASYNC, "Write", bp);
return bp;
}
static struct mbuf *
async_Decode(struct async *async, u_char c)
{
struct mbuf *bp;
if ((async->mode & MODE_HUNT) && c != HDLC_SYN)
return NULL;
switch (c) {
case HDLC_SYN:
async->mode &= ~MODE_HUNT;
if (async->length) { /* packet is ready. */
bp = mbuf_Alloc(async->length, MB_ASYNCIN);
mbuf_Write(bp, async->hbuff, async->length);
async->length = 0;
return bp;
}
break;
case HDLC_ESC:
if (!(async->mode & MODE_ESC)) {
async->mode |= MODE_ESC;
break;
}
/* Fall into ... */
default:
if (async->length >= HDLCSIZE) {
/* packet is too large, discard it */
log_Printf(LogWARN, "Packet too large (%d), discarding.\n",
async->length);
async->length = 0;
async->mode = MODE_HUNT;
break;
}
if (async->mode & MODE_ESC) {
c ^= HDLC_XOR;
async->mode &= ~MODE_ESC;
}
async->hbuff[async->length++] = c;
break;
}
return NULL;
}
static struct mbuf *
async_LayerPull(struct bundle *b, struct link *l, struct mbuf *bp,
u_short *proto)
{
struct mbuf *nbp, **last;
struct physical *p = link2physical(l);
u_char *ch;
size_t cnt;
if (!p) {
log_Printf(LogERROR, "Can't Pull an async packet from a logical link\n");
return bp;
}
last = &nbp;
log_DumpBp(LogASYNC, "Read", bp);
while (bp) {
ch = MBUF_CTOP(bp);
for (cnt = bp->cnt; cnt; cnt--) {
*last = async_Decode(&p->async, *ch++);
if (*last != NULL)
last = &(*last)->pnext;
}
bp = mbuf_FreeSeg(bp);
}
return nbp;
}
struct layer asynclayer =
{ LAYER_ASYNC, "async", async_LayerPush, async_LayerPull };
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