[src/trunk]: src/sys Fix in_undefer_cksum() and in6_undefer_cksum().

[rin <rin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/282ee1e549ab
branches:  trunk
changeset: 835965:282ee1e549ab
user:      rin <rin%NetBSD.org@localhost>
date:      Wed Sep 19 07:54:11 2018 +0000

description:
Fix in_undefer_cksum() and in6_undefer_cksum().

The 4th argument for in[46]_cksum() should be length of L4 header +
L4 payload. The previous revisions are wrong

- for IPv4 when hdrlen != 0
- for IPv6 always

These functions are used only in net/if_loop.c and
arch/powerpc/booke/dev/pq3etsec.c under some special circumferences.
This should be why the bugs have not been found until today.

OK maxv

diffstat:

 sys/netinet/in_offload.c   |  6 +++---
 sys/netinet6/in6_offload.c |  7 ++++---
 2 files changed, 7 insertions(+), 6 deletions(-)

diffs (55 lines):

diff -r a59db1828f73 -r 282ee1e549ab sys/netinet/in_offload.c
--- a/sys/netinet/in_offload.c  Wed Sep 19 07:51:23 2018 +0000
+++ b/sys/netinet/in_offload.c  Wed Sep 19 07:54:11 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: in_offload.c,v 1.11 2018/07/11 06:25:05 maxv Exp $     */
+/*     $NetBSD: in_offload.c,v 1.12 2018/09/19 07:54:11 rin Exp $      */
 
 /*
  * Copyright (c)2005, 2006 YAMAMOTO Takashi,
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.11 2018/07/11 06:25:05 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.12 2018/09/19 07:54:11 rin Exp $");
 
 #include <sys/param.h>
 #include <sys/mbuf.h>
@@ -213,7 +213,7 @@
        if (csum_flags & (M_CSUM_UDPv4|M_CSUM_TCPv4)) {
                size_t l4offset = hdrlen + iphdrlen;
 
-               csum = in4_cksum(m, 0, l4offset, ip_len - l4offset - hdrlen);
+               csum = in4_cksum(m, 0, l4offset, ip_len - iphdrlen);
                if (csum == 0 && (csum_flags & M_CSUM_UDPv4) != 0)
                        csum = 0xffff;
 
diff -r a59db1828f73 -r 282ee1e549ab sys/netinet6/in6_offload.c
--- a/sys/netinet6/in6_offload.c        Wed Sep 19 07:51:23 2018 +0000
+++ b/sys/netinet6/in6_offload.c        Wed Sep 19 07:54:11 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: in6_offload.c,v 1.10 2018/08/10 06:55:04 maxv Exp $    */
+/*     $NetBSD: in6_offload.c,v 1.11 2018/09/19 07:54:11 rin Exp $     */
 
 /*
  * Copyright (c)2006 YAMAMOTO Takashi,
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: in6_offload.c,v 1.10 2018/08/10 06:55:04 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: in6_offload.c,v 1.11 2018/09/19 07:54:11 rin Exp $");
 
 #include <sys/param.h>
 #include <sys/mbuf.h>
@@ -193,7 +193,8 @@
 
        l4hdroff = M_CSUM_DATA_IPv6_IPHL(m->m_pkthdr.csum_data);
        l4offset = hdrlen + l4hdroff;
-       csum = in6_cksum(m, 0, l4offset, plen - l4hdroff);
+       csum = in6_cksum(m, 0, l4offset,
+           plen - (l4hdroff - sizeof(struct ip6_hdr)));
 
        if (csum == 0 && (csum_flags & M_CSUM_UDPv6) != 0)
                csum = 0xffff;