Module Name: src
Committed By: maxv
Date: Fri Apr 13 07:30:46 UTC 2018
Modified Files:
src/sys/sys: mbuf.h
Log Message:
Improve comment.
To generate a diff of this commit:
cvs rdiff -u -r1.182 -r1.183 src/sys/sys/mbuf.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/sys/mbuf.h
diff -u src/sys/sys/mbuf.h:1.182 src/sys/sys/mbuf.h:1.183
--- src/sys/sys/mbuf.h:1.182 Tue Apr 10 16:12:30 2018
+++ src/sys/sys/mbuf.h Fri Apr 13 07:30:46 2018
@@ -1,4 +1,4 @@
-/* $NetBSD: mbuf.h,v 1.182 2018/04/10 16:12:30 maxv Exp $ */
+/* $NetBSD: mbuf.h,v 1.183 2018/04/13 07:30:46 maxv Exp $ */
/*
* Copyright (c) 1996, 1997, 1999, 2001, 2007 The NetBSD Foundation, Inc.
@@ -161,15 +161,22 @@ struct m_hdr {
/*
* record/packet header in first mbuf of chain; valid if M_PKTHDR set
*
- * A note about csum_data: For the out-bound direction, the low 16 bits
- * indicates the offset after the L4 header where the final L4 checksum value
- * is to be stored and the high 16 bits is the length of the L3 header (the
- * start of the data to be checksumed). For the in-bound direction, it is only
- * valid if the M_CSUM_DATA flag is set. In this case, an L4 checksum has been
- * calculated by hardware, but it is up to software to perform final
- * verification.
+ * A note about csum_data:
*
- * Note for in-bound TCP/UDP checksums, we expect the csum_data to NOT
+ * o For the out-bound direction, the low 16 bits indicates the offset after
+ * the L4 header where the final L4 checksum value is to be stored
+ * (checksumming flags) and the high 16 bits is the length of the L3 header
+ * (the start of the data to be checksummed):
+ *
+ * +------------------+--------------------+
+ * csum_data: | L3 header length | Checksumming flags |
+ * +------------------+--------------------+
+ *
+ * o For the in-bound direction, it is only valid if the M_CSUM_DATA flag is
+ * set. In this case, an L4 checksum has been calculated by hardware, but
+ * it is up to software to perform final verification.
+ *
+ * Note for in-bound TCP/UDP checksums: we expect the csum_data to NOT
* be bit-wise inverted (the final step in the calculation of an IP
* checksum) -- this is so we can accumulate the checksum for fragmented
* packets during reassembly.
