X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=modules%2Fbsd-comp.c;h=b730c0738953b89040ef4c2b5ed35d1d46c90d32;hb=9faea8a8533fe693a25a2bec728c969099809ab7;hp=a9852789534174d546c269920ce6d856689403f8;hpb=7aa1222ea5fe1d3459c9cb31c2dc41d2f3826554;p=ppp.git

diff --git a/modules/bsd-comp.c b/modules/bsd-comp.c
index a985278..b730c07 100644
--- a/modules/bsd-comp.c
+++ b/modules/bsd-comp.c
@@ -39,6 +39,8 @@
 
 /*
  * This version is for use with STREAMS under SunOS 4.x.
+ *
+ * $Id: bsd-comp.c,v 1.3 1994/08/31 23:58:53 paulus Exp $
  */
 
 #include <sys/param.h>
@@ -492,20 +494,22 @@ bsd_compress(state, mret, mp, slen, maxolen)
 	wptr = cp_end = NULL;
     olen = 0;
 
-    /* Copy the PPP header over, changing the protocol */
-    if (wptr) {
-	*wptr++ = rptr[0];	/* assumes the ppp header is */
-	*wptr++ = rptr[1];	/* all in one mblk */
-	*wptr++ = 0;		/* change the protocol */
-	*wptr++ = PPP_COMP;
-    }
-
-    /* install the 3-byte sequence number */
+    /*
+     * Copy the PPP header over, changing the protocol,
+     * and install the 3-byte sequence number.
+     */
     slen += db->seqno - PPP_HDRLEN + 1;
     db->seqno = slen;
-    *wptr++ = slen>>16;
-    *wptr++ = slen>>8;
-    *wptr++ = slen;
+    if (wptr) {
+	wptr[0] = rptr[0];	/* assumes the ppp header is */
+	wptr[1] = rptr[1];	/* all in one mblk */
+	wptr[2] = 0;		/* change the protocol */
+	wptr[3] = PPP_COMP;
+	wptr[4] = slen>>16;
+	wptr[5] = slen>>8;
+	wptr[6] = slen;
+	wptr += PPP_HDRLEN + BSD_OVHD;
+    }
 
     /* start with the protocol byte */
     ent = rptr[3];
@@ -767,10 +771,13 @@ bsd_decompress(state, cmsg, hdroff)
     rptr += 3;
     len = cmsg->b_wptr - rptr;
 
-    /* check the sequence number and give up if the length is nonsense */
+    /*
+     * Check the sequence number and give up if the length is nonsense.
+     * The check is against mru+1 because we compress one byte of protocol.
+     */
     explen = (seq - db->seqno) & 0xffffff;
     db->seqno = seq;
-    if (explen > db->mru || explen < 1) {
+    if (explen > db->mru + 1 || explen < 1) {
 	if (db->debug)
 	    printf("bsd_decomp%d: bad length 0x%x\n", db->unit, explen);
 	return 0;