From de10b83a231451e03d08b3293c503d11ea03a90b Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 11 Mar 1999 00:26:21 +0000
Subject: [PATCH] 	* local label offset 255 is reserved. 	* don't add
 domainnames with local compression pointers as 	  valid global
 compression targets unless edns is high enough.

---
 lib/dns/compress.c             | 20 +++++++++++---------
 lib/dns/include/dns/compress.h |  8 ++++++--
 lib/dns/name.c                 |  6 +++---
 3 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/lib/dns/compress.c b/lib/dns/compress.c
index d53d02632e..8a84e32721 100644
--- a/lib/dns/compress.c
+++ b/lib/dns/compress.c
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
- /* $Id: compress.c,v 1.6 1999/03/06 04:08:29 halley Exp $ */
+ /* $Id: compress.c,v 1.7 1999/03/11 00:26:20 marka Exp $ */
 
 #include <config.h>
 
@@ -124,7 +124,7 @@ dns_compress_localinit(dns_compress_t *cctx, dns_name_t *owner,
 		labels --;
 		wl++;
 		ll++;
-		if (ll > 255)
+		if (ll > 254)
 			return (DNS_R_SUCCESS);
 		dns_name_getlabel(&name, 0, &label);
 		if (dns_label_type(&label) != dns_labeltype_bitstring)
@@ -159,7 +159,7 @@ dns_compress_localinit(dns_compress_t *cctx, dns_name_t *owner,
 				return (DNS_R_SUCCESS);
 			}
 			ll++;
-			if (ll > 255)
+			if (ll > 254)
 				return (DNS_R_SUCCESS);
 		} while (bits > 1);
 	}
@@ -242,19 +242,21 @@ dns_compress_findlocal(dns_compress_t *cctx, dns_name_t *name,
 
 void
 dns_compress_add(dns_compress_t *cctx, dns_name_t *prefix,
-		 dns_name_t *suffix, isc_uint16_t offset)
+		 dns_name_t *suffix, isc_uint16_t offset,
+		 isc_boolean_t local)
 {
-	isc_uint16_t local;
+	isc_uint16_t localoffset;
 	REQUIRE(VALID_CCTX(cctx));
 
 	if (cctx->local != NULL && (cctx->allowed & DNS_COMPRESS_LOCAL) != 0) {
 		REQUIRE(cctx->rdata <= offset);
-		local = offset - cctx->rdata + 256;
-		compress_add(cctx->local, prefix, suffix, local, ISC_TRUE,
+		localoffset = offset - cctx->rdata + 256;
+		compress_add(cctx->local, prefix, suffix, localoffset, ISC_TRUE,
 			     cctx->mctx);
 	}
-	compress_add(cctx->global, prefix, suffix, offset, cctx->global16,
-		     cctx->mctx);
+	if ((cctx->edns > -1) || !local)
+		compress_add(cctx->global, prefix, suffix, offset,
+			     cctx->global16, cctx->mctx);
 }
 
 void
diff --git a/lib/dns/include/dns/compress.h b/lib/dns/include/dns/compress.h
index 2142ce7bd6..9ca23b1cd5 100644
--- a/lib/dns/include/dns/compress.h
+++ b/lib/dns/include/dns/compress.h
@@ -208,10 +208,14 @@ dns_compress_findlocal(dns_compress_t *cctx, dns_name_t *name,
 
 void
 dns_compress_add(dns_compress_t *cctx, dns_name_t *prefix,
-		 dns_name_t *suffix, isc_uint16_t offset);
+		 dns_name_t *suffix, isc_uint16_t offset,
+		 isc_boolean_t local);
 /*
  *	Add compression pointers for labels in prefix to RBT's.
- *	If 'prefix' is absolute 'suffix' must be NULL.
+ *	If 'prefix' is absolute 'suffix' must be NULL otherwise
+ *	suffix must be absolute.
+ *	'local' indicates that the domain name at offset contains
+ *	a local compression pointer.
  *
  *	Requires:
  *		'cctx' initalised
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 92ec4afce1..6dd281cda2 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -2057,7 +2057,7 @@ dns_name_towire(dns_name_t *name, dns_compress_t *cctx,
 			isc_buffer_putuint16(target, go);
 		}
 		if (gp.length != 0)
-			dns_compress_add(cctx, &gp, &gs, offset);
+			dns_compress_add(cctx, &gp, &gs, offset, ISC_FALSE);
 	} else if (lf) {
 		if (target->length - target->used < lp.length)
 			return (DNS_R_NOSPACE);
@@ -2078,14 +2078,14 @@ dns_name_towire(dns_name_t *name, dns_compress_t *cctx,
 			isc_buffer_putuint16(target, lo);
 		}
 		if (lp.length != 0)
-			dns_compress_add(cctx, &lp, &ls, offset);
+			dns_compress_add(cctx, &lp, &ls, offset, ISC_TRUE);
 	} else {
 		if (target->length - target->used < name->length)
 			return (DNS_R_NOSPACE);
 		(void)memcpy((unsigned char *)target->base + target->used,
 			     name->ndata, (size_t)name->length);
 		isc_buffer_add(target, name->length);
-		dns_compress_add(cctx, name, NULL, offset);
+		dns_compress_add(cctx, name, NULL, offset, ISC_FALSE);
 	}
 	return (DNS_R_SUCCESS);
 }