[src/trunk]: src/sys/netinet6 Revert r1.148

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

details:   https://anonhg.NetBSD.org/src/rev/524e2bd12f04
branches:  trunk
changeset: 817399:524e2bd12f04
user:      roy <roy%NetBSD.org@localhost>
date:      Fri Aug 19 12:26:01 2016 +0000

description:
Revert r1.148
IP6_EXTHDR_GET ensures that a icmp6 header can be fetched from the mbuf
so m_pullup does not need to be called.

While here, we can safely increament interface error stats even with an
invalidated mbuf because we have a saved reference to the interface.

diffstat:

 sys/netinet6/icmp6.c |  28 +++++++++-------------------
 1 files changed, 9 insertions(+), 19 deletions(-)

diffs (70 lines):

diff -r 8320b980515f -r 524e2bd12f04 sys/netinet6/icmp6.c
--- a/sys/netinet6/icmp6.c      Fri Aug 19 11:51:27 2016 +0000
+++ b/sys/netinet6/icmp6.c      Fri Aug 19 12:26:01 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: icmp6.c,v 1.195 2016/08/01 03:15:31 ozaki-r Exp $      */
+/*     $NetBSD: icmp6.c,v 1.196 2016/08/19 12:26:01 roy Exp $  */
 /*     $KAME: icmp6.c,v 1.217 2001/06/20 15:03:29 jinmei Exp $ */
 
 /*
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: icmp6.c,v 1.195 2016/08/01 03:15:31 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: icmp6.c,v 1.196 2016/08/19 12:26:01 roy Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -452,7 +452,7 @@
        struct icmp6_hdr *icmp6, *nicmp6;
        int off = *offp;
        int icmp6len = m->m_pkthdr.len - *offp;
-       int code, sum, noff, i;
+       int code, sum, noff;
        struct ifnet *rcvif;
        struct psref psref;
 
@@ -475,29 +475,18 @@
                goto freeit;
        }
 
-       i = off + sizeof(*icmp6);
-       if ((m->m_len < i || M_READONLY(m)) && (m = m_pullup(m, i)) == 0) {
+       ip6 = mtod(m, struct ip6_hdr *);
+       IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
+       if (icmp6 == NULL) {
                ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
-#if 0 /* m is 0 here */
                icmp6_ifstat_inc(rcvif, ifs6_in_error);
-#endif
                goto freeit;
        }
-       ip6 = mtod(m, struct ip6_hdr *);
+       KASSERT(IP6_HDR_ALIGNED_P(icmp6));
+
        /*
         * calculate the checksum
         */
-       IP6_EXTHDR_GET(icmp6, struct icmp6_hdr *, m, off, sizeof(*icmp6));
-       if (icmp6 == NULL) {
-               m_put_rcvif_psref(rcvif, &psref);
-               ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
-               /* m is invalid */
-               /*icmp6_ifstat_inc(rcvif, ifs6_in_error);*/
-               return IPPROTO_DONE;
-       }
-       KASSERT(IP6_HDR_ALIGNED_P(icmp6));
-       code = icmp6->icmp6_code;
-
        if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
                nd6log(LOG_ERR, "ICMP6 checksum error(%d|%x) %s\n",
                    icmp6->icmp6_type, sum, ip6_sprintf(&ip6->ip6_src));
@@ -524,6 +513,7 @@
        }
 #endif
 
+       code = icmp6->icmp6_code;
        ICMP6_STATINC(ICMP6_STAT_INHIST + icmp6->icmp6_type);
 
        switch (icmp6->icmp6_type) {