ppp-2.3.x ships with a bad compression number for deflate. It uses number

24 (which is magnalink!) rather than the correct (according to the rfc) 26.

Initial attempt at a compatability kludge that will negotiate for either
but will prefer to use the correct deflate compression type.

usr.sbin/pppd/ccp.c

@@ -26,7 +26,7 @@
  */
 
 #ifndef lint
-static char rcsid[] = "$Id$";
+static char rcsid[] = "$Id: ccp.c,v 1.7 1997/08/19 17:52:33 peter Exp $";
 #endif
 
 #include <string.h>
@@ -116,8 +116,14 @@ static fsm_callbacks ccp_callbacks = {
 /*
  * Do we want / did we get any compression?
  */
+#ifdef CI_BADDEFLATE
+#define ANY_COMPRESS(opt)	((opt).deflate || (opt).baddeflate \
+				 || (opt).bsd_compress \
+				 || (opt).predictor_1 || (opt).predictor_2)
+#else
 #define ANY_COMPRESS(opt)	((opt).deflate || (opt).bsd_compress \
 				 || (opt).predictor_1 || (opt).predictor_2)
+#endif
 
 /*
  * Local state (mainly for handling reset-reqs and reset-acks).
@@ -154,6 +160,13 @@ ccp_init(unit)
     ccp_allowoptions[0].deflate = 1;
     ccp_allowoptions[0].deflate_size = DEFLATE_MAX_SIZE;
 
+#ifdef CI_BADDEFLATE
+    ccp_wantoptions[0].baddeflate = 1;
+    ccp_wantoptions[0].baddeflate_size = DEFLATE_MAX_SIZE;
+    ccp_allowoptions[0].baddeflate = 1;
+    ccp_allowoptions[0].baddeflate_size = DEFLATE_MAX_SIZE;
+#endif
+
     ccp_wantoptions[0].bsd_compress = 1;
     ccp_wantoptions[0].bsd_bits = BSD_MAX_BITS;
     ccp_allowoptions[0].bsd_compress = 1;
@@ -322,6 +335,16 @@ ccp_resetci(f)
 	if (ccp_test(f->unit, opt_buf, CILEN_DEFLATE, 0) <= 0)
 	    go->deflate = 0;
     }
+#ifdef CI_BADDEFLATE
+    if (go->baddeflate) {
+	opt_buf[0] = CI_BADDEFLATE;
+	opt_buf[1] = CILEN_DEFLATE;
+	opt_buf[2] = DEFLATE_MAKE_OPT(DEFLATE_MIN_SIZE);
+	opt_buf[3] = DEFLATE_CHK_SEQUENCE;
+	if (ccp_test(f->unit, opt_buf, CILEN_DEFLATE, 0) <= 0)
+	    go->baddeflate = 0;
+    }
+#endif
     if (go->predictor_1) {
 	opt_buf[0] = CI_PREDICTOR_1;
 	opt_buf[1] = CILEN_PREDICTOR_1;
@@ -347,6 +370,9 @@ ccp_cilen(f)
 
     return (go->bsd_compress? CILEN_BSD_COMPRESS: 0)
 	+ (go->deflate? CILEN_DEFLATE: 0)
+#ifdef CI_BADDEFLATE
+	+ (go->baddeflate? CILEN_DEFLATE: 0)
+#endif
 	+ (go->predictor_1? CILEN_PREDICTOR_1: 0)
 	+ (go->predictor_2? CILEN_PREDICTOR_2: 0);
 }
@@ -388,6 +414,31 @@ ccp_addci(f, p, lenp)
 	    p[2] = DEFLATE_MAKE_OPT(go->deflate_size);
 	}
     }
+#ifdef CI_BADDEFLATE
+    if (go->baddeflate) {
+	p[0] = CI_BADDEFLATE;
+	p[1] = CILEN_DEFLATE;
+	p[2] = DEFLATE_MAKE_OPT(go->baddeflate_size);
+	p[3] = DEFLATE_CHK_SEQUENCE;
+	if (p != p0) {
+	    p += CILEN_DEFLATE;		/* not the first option */
+	} else {
+	    for (;;) {
+		res = ccp_test(f->unit, p, CILEN_DEFLATE, 0);
+		if (res > 0) {
+		    p += CILEN_DEFLATE;
+		    break;
+		}
+		if (res < 0 || go->baddeflate_size <= DEFLATE_MIN_SIZE) {
+		    go->baddeflate = 0;
+		    break;
+		}
+		--go->baddeflate_size;
+		p[2] = DEFLATE_MAKE_OPT(go->baddeflate_size);
+	    }
+	}
+    }
+#endif
     if (go->bsd_compress) {
 	p[0] = CI_BSD_COMPRESS;
 	p[1] = CILEN_BSD_COMPRESS;
@@ -460,6 +511,20 @@ ccp_ackci(f, p, len)
 	if (len == 0)
 	    return 1;
     }
+#ifdef CI_BADDEFLATE
+    if (go->baddeflate) {
+	if (len < CILEN_DEFLATE
+	    || p[0] != CI_BADDEFLATE || p[1] != CILEN_DEFLATE
+	    || p[2] != DEFLATE_MAKE_OPT(go->baddeflate_size)
+	    || p[3] != DEFLATE_CHK_SEQUENCE)
+	    return 0;
+	p += CILEN_DEFLATE;
+	len -= CILEN_DEFLATE;
+	/* XXX Cope with first/fast ack */
+	if (p == p0 && len == 0)
+	    return 1;
+    }
+#endif
     if (go->bsd_compress) {
 	if (len < CILEN_BSD_COMPRESS
 	    || p[0] != CI_BSD_COMPRESS || p[1] != CILEN_BSD_COMPRESS
@@ -531,6 +596,25 @@ ccp_nakci(f, p, len)
 	len -= CILEN_DEFLATE;
     }
 
+#ifdef CI_BADDEFLATE
+    if (go->baddeflate && len >= CILEN_DEFLATE
+	&& p[0] == CI_BADDEFLATE && p[1] == CILEN_DEFLATE) {
+	no.baddeflate = 1;
+	/*
+	 * Peer wants us to use a different code size or something.
+	 * Stop asking for Deflate if we don't understand his suggestion.
+	 */
+	if (DEFLATE_METHOD(p[2]) != DEFLATE_METHOD_VAL
+	    || DEFLATE_SIZE(p[2]) < DEFLATE_MIN_SIZE
+	    || p[3] != DEFLATE_CHK_SEQUENCE)
+	    try.baddeflate = 0;
+	else if (DEFLATE_SIZE(p[2]) < go->baddeflate_size)
+	    try.baddeflate_size = DEFLATE_SIZE(p[2]);
+	p += CILEN_DEFLATE;
+	len -= CILEN_DEFLATE;
+    }
+#endif
+
     if (go->bsd_compress && len >= CILEN_BSD_COMPRESS
 	&& p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD_COMPRESS) {
 	no.bsd_compress = 1;
@@ -590,6 +674,17 @@ ccp_rejci(f, p, len)
 	p += CILEN_DEFLATE;
 	len -= CILEN_DEFLATE;
     }
+#ifdef CI_BADDEFLATE
+    if (go->baddeflate && len >= CILEN_DEFLATE
+	&& p[0] == CI_BADDEFLATE && p[1] == CILEN_DEFLATE) {
+	if (p[2] != DEFLATE_MAKE_OPT(go->baddeflate_size)
+	    || p[3] != DEFLATE_CHK_SEQUENCE)
+	    return 0;		/* Rej is bad */
+	try.baddeflate = 0;
+	p += CILEN_DEFLATE;
+	len -= CILEN_DEFLATE;
+    }
+#endif
     if (go->bsd_compress && len >= CILEN_BSD_COMPRESS
 	&& p[0] == CI_BSD_COMPRESS && p[1] == CILEN_BSD_COMPRESS) {
 	if (p[2] != BSD_MAKE_OPT(BSD_CURRENT_VERSION, go->bsd_bits))
@@ -700,6 +795,51 @@ ccp_reqci(f, p, lenp, dont_nak)
 		}
 		break;
 
+#ifdef CI_BADDEFLATE
+	    case CI_BADDEFLATE:
+		if (!ao->baddeflate || clen != CILEN_DEFLATE) {
+		    newret = CONFREJ;
+		    break;
+		}
+
+		ho->baddeflate = 1;
+		ho->baddeflate_size = nb = DEFLATE_SIZE(p[2]);
+		if (DEFLATE_METHOD(p[2]) != DEFLATE_METHOD_VAL
+		    || p[3] != DEFLATE_CHK_SEQUENCE
+		    || nb > ao->baddeflate_size || nb < DEFLATE_MIN_SIZE) {
+		    newret = CONFNAK;
+		    if (!dont_nak) {
+			p[2] = DEFLATE_MAKE_OPT(ao->baddeflate_size);
+			p[3] = DEFLATE_CHK_SEQUENCE;
+			/* fall through to test this #bits below */
+		    } else
+			break;
+		}
+
+		/*
+		 * Check whether we can do Deflate with the window
+		 * size they want.  If the window is too big, reduce
+		 * it until the kernel can cope and nak with that.
+		 * We only check this for the first option.
+		 */
+		if (p == p0) {
+		    for (;;) {
+			res = ccp_test(f->unit, p, CILEN_DEFLATE, 1);
+			if (res > 0)
+			    break;		/* it's OK now */
+			if (res < 0 || nb == DEFLATE_MIN_SIZE || dont_nak) {
+			    newret = CONFREJ;
+			    p[2] = DEFLATE_MAKE_OPT(ho->baddeflate_size);
+			    break;
+			}
+			newret = CONFNAK;
+			--nb;
+			p[2] = DEFLATE_MAKE_OPT(nb);
+		    }
+		}
+		break;
+#endif
+
 	    case CI_BSD_COMPRESS:
 		if (!ao->bsd_compress || clen != CILEN_BSD_COMPRESS) {
 		    newret = CONFREJ;
@@ -817,6 +957,15 @@ method_name(opt, opt2)
 	else
 	    sprintf(result, "Deflate (%d)", opt->deflate_size);
 	break;
+#ifdef CI_BADDEFLATE
+    case CI_BADDEFLATE:
+	if (opt2 != NULL && opt2->baddeflate_size != opt->baddeflate_size)
+	    sprintf(result, "Bad-Deflate (%d/%d)", opt->baddeflate_size,
+		    opt2->baddeflate_size);
+	else
+	    sprintf(result, "Bad-Deflate (%d)", opt->baddeflate_size);
+	break;
+#endif
     case CI_BSD_COMPRESS:
 	if (opt2 != NULL && opt2->bsd_bits != opt->bsd_bits)
 	    sprintf(result, "BSD-Compress (%d/%d)", opt->bsd_bits,
@@ -941,6 +1090,18 @@ ccp_printpkt(p, plen, printer, arg)
 		    p += CILEN_DEFLATE;
 		}
 		break;
+#ifdef CI_BADDEFLATE
+	    case CI_BADDEFLATE:
+		if (optlen >= CILEN_DEFLATE) {
+		    printer(arg, "baddeflate %d", DEFLATE_SIZE(p[2]));
+		    if (DEFLATE_METHOD(p[2]) != DEFLATE_METHOD_VAL)
+			printer(arg, " method %d", DEFLATE_METHOD(p[2]));
+		    if (p[3] != DEFLATE_CHK_SEQUENCE)
+			printer(arg, " check %d", p[3]);
+		    p += CILEN_DEFLATE;
+		}
+		break;
+#endif
 	    case CI_BSD_COMPRESS:
 		if (optlen >= CILEN_BSD_COMPRESS) {
 		    printer(arg, "bsd v%d %d", BSD_VERSION(p[2]),

usr.sbin/pppd/ccp.h

@@ -24,16 +24,18 @@
  * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
  * OR MODIFICATIONS.
  *
- * $Id$
+ * $Id: ccp.h,v 1.5 1997/08/19 17:52:33 peter Exp $
  */
 
 typedef struct ccp_options {
     u_int bsd_compress: 1;	/* do BSD Compress? */
-    u_int deflate: 1;		/* do Deflate? */
+    u_int deflate: 1;		/* do Deflate? (RFC code) */
+    u_int baddeflate: 1;	/* do Deflate? (Magnalink!) */
     u_int predictor_1: 1;	/* do Predictor-1? */
     u_int predictor_2: 1;	/* do Predictor-2? */
     u_short bsd_bits;		/* # bits/code for BSD Compress */
     u_short deflate_size;	/* lg(window size) for Deflate */
+    u_short baddeflate_size;	/* lg(window size) for Deflate */
     short method;		/* code for chosen compression method */
 } ccp_options;
 

usr.sbin/pppd/options.c

@@ -18,7 +18,7 @@
  */
 
 #ifndef lint
-static char rcsid[] = "$Id: options.c,v 1.16 1997/10/10 09:28:37 peter Exp $";
+static char rcsid[] = "$Id: options.c,v 1.17 1998/03/22 05:33:03 peter Exp $";
 #endif
 
 #include <ctype.h>
@@ -216,6 +216,7 @@ static int setbsdcomp __P((char **));
 static int setnobsdcomp __P((char **));
 static int setdeflate __P((char **));
 static int setnodeflate __P((char **));
+static int setnobaddeflate __P((char **));
 static int setdemand __P((char **));
 static int setpred1comp __P((char **));
 static int setnopred1comp __P((char **));
@@ -370,6 +371,8 @@ static struct cmd {
     {"deflate", 1, setdeflate},		/* request Deflate compression */
     {"nodeflate", 0, setnodeflate},	/* don't allow Deflate compression */
     {"-deflate", 0, setnodeflate},	/* don't allow Deflate compression */
+    {"nobaddeflate", 0, setnobaddeflate}, /* don't allow (wrong) Deflate */
+    {"-baddeflate", 0, setnobaddeflate}, /* don't allow (wrong) Deflate */
     {"predictor1", 0, setpred1comp},	/* request Predictor-1 */
     {"nopredictor1", 0, setnopred1comp},/* don't allow Predictor-1 */
     {"-predictor1", 0, setnopred1comp},	/* don't allow Predictor-1 */
@@ -2220,6 +2223,13 @@ setdeflate(argv)
 	ccp_allowoptions[0].deflate_size = abits;
     } else
 	ccp_allowoptions[0].deflate = 0;
+
+    /* XXX copy over settings for switch compatability */
+    ccp_wantoptions[0].baddeflate = ccp_wantoptions[0].deflate;
+    ccp_wantoptions[0].baddeflate_size = ccp_wantoptions[0].deflate_size;
+    ccp_allowoptions[0].baddeflate = ccp_allowoptions[0].deflate;
+    ccp_allowoptions[0].baddeflate_size = ccp_allowoptions[0].deflate_size;
+
     return 1;
 }
 
@@ -2232,6 +2242,15 @@ setnodeflate(argv)
     return 1;
 }
 
+static int
+setnobaddeflate(argv)
+    char **argv;
+{
+    ccp_wantoptions[0].baddeflate = 0;
+    ccp_allowoptions[0].baddeflate = 0;
+    return 1;
+}
+
 static int
 setpred1comp(argv)
     char **argv;