[src/trunk]: src/sys/netinet ip_undefer_csum:

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

details:   https://anonhg.NetBSD.org/src/rev/94572d4dceb6
branches:  trunk
changeset: 764495:94572d4dceb6
user:      yamt <yamt%NetBSD.org@localhost>
date:      Mon Apr 25 22:11:31 2011 +0000

description:
ip_undefer_csum:
- don't forget ntohs.
- don't add hdrlen twice for l4 header offset.
- use M_CSUM_DATA_IPv4_IPHL instead of extracting it from ip header.
- simplify code.
- KNF.

diffstat:

 sys/netinet/in_offload.c |  30 ++++++++++++++++--------------
 1 files changed, 16 insertions(+), 14 deletions(-)

diffs (75 lines):

diff -r 3e72c613a0bf -r 94572d4dceb6 sys/netinet/in_offload.c
--- a/sys/netinet/in_offload.c  Mon Apr 25 22:09:29 2011 +0000
+++ b/sys/netinet/in_offload.c  Mon Apr 25 22:11:31 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: in_offload.c,v 1.4 2011/04/14 15:53:36 yamt Exp $      */
+/*     $NetBSD: in_offload.c,v 1.5 2011/04/25 22:11:31 yamt Exp $      */
 
 /*-
  * Copyright (c)2005, 2006 YAMAMOTO Takashi,
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.4 2011/04/14 15:53:36 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.5 2011/04/25 22:11:31 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/mbuf.h>
@@ -203,42 +203,44 @@
 void
 ip_undefer_csum(struct mbuf *m, size_t hdrlen, int csum_flags)
 {
-       KASSERT(m->m_flags & M_PKTHDR);
-       KASSERT((m->m_pkthdr.csum_flags & csum_flags) == csum_flags);
+       const size_t iphdrlen = M_CSUM_DATA_IPv4_IPHL(m->m_pkthdr.csum_data);
        uint16_t csum;
        uint16_t ip_len;
        uint16_t *csump;
-       size_t iphdrlen;
+
+       KASSERT(m->m_flags & M_PKTHDR);
+       KASSERT((m->m_pkthdr.csum_flags & csum_flags) == csum_flags);
 
        if (__predict_true(hdrlen + sizeof(struct ip) <= m->m_len)) {
                struct ip *ip = (struct ip *)(mtod(m, uint8_t *) + hdrlen);
+
                ip_len = ip->ip_len;
-               iphdrlen = ip->ip_hl << 2;
                csump = &ip->ip_sum;
        } else {
-               uint8_t ip_vhl;
-               const size_t ip_len_offset = hdrlen + offsetof(struct ip, ip_len);
-               m_copydata(m, hdrlen, sizeof(ip_vhl), &ip_vhl);
+               const size_t ip_len_offset =
+                   hdrlen + offsetof(struct ip, ip_len);
+
                m_copydata(m, ip_len_offset, sizeof(ip_len), &ip_len);
-               iphdrlen = (ip_vhl & 0x0f) << 2;
                csump = NULL;
        }
+       ip_len = ntohs(ip_len);
 
        if (csum_flags & M_CSUM_IPv4) {
-               const size_t offset = hdrlen + offsetof(struct ip, ip_sum);
                csum = in4_cksum(m, 0, hdrlen, iphdrlen);
                if (csump != NULL) {
                        *csump = csum;
                } else {
+                       const size_t offset = hdrlen +
+                           offsetof(struct ip, ip_sum);
+
                        m_copyback(m, offset, sizeof(uint16_t), &csum);
                }
        }
 
        if (csum_flags & (M_CSUM_UDPv4|M_CSUM_TCPv4)) {
-               size_t l4offset = hdrlen
-                   + M_CSUM_DATA_IPv4_IPHL(m->m_pkthdr.csum_data);
+               size_t l4offset = hdrlen + iphdrlen;
 
-               csum = in4_cksum(m, 0, hdrlen + l4offset, ip_len - l4offset);
+               csum = in4_cksum(m, 0, l4offset, ip_len - l4offset - hdrlen);
                if (csum == 0 && (csum_flags & M_CSUM_UDPv4) != 0)
                        csum = 0xffff;