From 1488cd3b73af55931af8731450369ae04a5d1c90 Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@etherboot.org>
Date: Fri, 28 Apr 2006 14:09:31 +0000
Subject: [PATCH] Fix a couple of broken assertions, and align the buffer
 correctly.

---
 src/include/gpxe/pkbuff.h | 4 ++--
 src/net/pkbuff.c          | 5 ++++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/include/gpxe/pkbuff.h b/src/include/gpxe/pkbuff.h
index 646b540d..92244fd5 100644
--- a/src/include/gpxe/pkbuff.h
+++ b/src/include/gpxe/pkbuff.h
@@ -33,7 +33,7 @@ struct ll_protocol;
  * This structure is used to represent a network packet within gPXE.
  */
 struct pk_buff {
-	/** Head of the buffer */
+	/** Start of the buffer */
 	void *head;
 	/** Start of data */
 	void *data;
@@ -87,7 +87,7 @@ static inline void * pkb_push ( struct pk_buff *pkb, size_t len ) {
  */
 static inline void * pkb_pull ( struct pk_buff *pkb, size_t len ) {
 	pkb->data += len;
-	assert ( pkb->data >= pkb->tail );
+	assert ( pkb->data <= pkb->tail );
 	return pkb->data;
 }
 
diff --git a/src/net/pkbuff.c b/src/net/pkbuff.c
index c1a6b2f7..964fbf62 100644
--- a/src/net/pkbuff.c
+++ b/src/net/pkbuff.c
@@ -40,7 +40,7 @@ struct pk_buff * alloc_pkb ( size_t len ) {
 	void *data;
 
 	/* Align buffer length */
-	len = ( len + __alignof__ ( *pkb ) - 1 ) & ~ __alignof__ ( *pkb );
+	len = ( len + __alignof__( *pkb ) - 1 ) & ~( __alignof__( *pkb ) - 1 );
 	
 	/* Allocate memory for buffer plus descriptor */
 	data = malloc_dma ( len + sizeof ( *pkb ), PKBUFF_ALIGN );
@@ -60,6 +60,9 @@ struct pk_buff * alloc_pkb ( size_t len ) {
  */
 void free_pkb ( struct pk_buff *pkb ) {
 	if ( pkb ) {
+		assert ( pkb->head <= pkb->data );
+		assert ( pkb->data <= pkb->tail );
+		assert ( pkb->tail <= pkb->end );
 		free_dma ( pkb->head,
 			   ( pkb->end - pkb->head ) + sizeof ( *pkb ) );
 	}