[src/trunk]: src document net.inet6.icmp6.mtudisc_{lo,hi}wat.

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

details:   https://anonhg.NetBSD.org/src/rev/3a7dd4a2b8a6
branches:  trunk
changeset: 500950:3a7dd4a2b8a6
user:      itojun <itojun%NetBSD.org@localhost>
date:      Thu Dec 21 01:10:52 2000 +0000

description:
document net.inet6.icmp6.mtudisc_{lo,hi}wat.

diffstat:

 lib/libc/gen/sysctl.3 |  18 +++++++++++++++++-
 sbin/sysctl/sysctl.8  |   4 +++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diffs (57 lines):

diff -r 9589f1a27a32 -r 3a7dd4a2b8a6 lib/libc/gen/sysctl.3
--- a/lib/libc/gen/sysctl.3     Thu Dec 21 00:52:01 2000 +0000
+++ b/lib/libc/gen/sysctl.3     Thu Dec 21 01:10:52 2000 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sysctl.3,v 1.70 2000/10/26 07:24:00 jdolecek Exp $
+.\"    $NetBSD: sysctl.3,v 1.71 2000/12/21 01:10:52 itojun Exp $
 .\"
 .\" Copyright (c) 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -898,6 +898,8 @@
 .It icmp6      nodeinfo        integer yes
 .It icmp6      errppslimit     integer yes
 .It icmp6      nd6_maxnudhint  integer yes
+.It icmp6      mtudisc_hiwat   integer yes
+.It icmp6      mtudisc_lowat   integer yes
 .It udp6       sendspace       integer yes
 .It udp6       recvspace       integer yes
 .El
@@ -1053,6 +1055,20 @@
 will take 3 consecutive hints in maximum.
 After receiving 3 hints, neighbor discovery layer will perform
 normal neighbor discovery process.
+.It Li icmp6.mtudisc_hiwat
+.It Li icmp6.mtudisc_lowat
+The variables define the maximum number of routing table entries,
+created due to path MTU discovery
+.Pq prevents denial-of-service attacks with ICMPv6 too big messages .
+When IPv6 path MTU discovery happens, we keep path MTU information into
+the routing table.
+If the number of routing table entries exceed the value,
+the kernel will not attempt to keep the path MTU information.
+.Li icmp6.mtudisc_hiwat
+is used when we have verified ICMPv6 too big messages.
+.Li icmp6.mtudisc_lowat
+is used when we have unverified ICMPv6 too big messages.
+Verification is performed by using address/port pairs kept in connected pcbs.
 .El
 .Pp
 We reuse net.*.tcp for
diff -r 9589f1a27a32 -r 3a7dd4a2b8a6 sbin/sysctl/sysctl.8
--- a/sbin/sysctl/sysctl.8      Thu Dec 21 00:52:01 2000 +0000
+++ b/sbin/sysctl/sysctl.8      Thu Dec 21 01:10:52 2000 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sysctl.8,v 1.60 2000/11/08 22:48:32 eeh Exp $
+.\"    $NetBSD: sysctl.8,v 1.61 2000/12/21 01:10:52 itojun Exp $
 .\"
 .\" Copyright (c) 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -262,6 +262,8 @@
 .It net.inet.udp.recvspace     integer yes
 .It net.inet.udp.sendspace     integer yes
 .It net.inet6.icmp6.errppslimit        integer yes
+.It net.inet6.icmp6.mtudisc_hiwat      integer yes
+.It net.inet6.icmp6.mtudisc_lowat      integer yes
 .It net.inet6.icmp6.nd6_delay  integer yes
 .It net.inet6.icmp6.nd6_maxnudhint     integer yes
 .It net.inet6.icmp6.nd6_mmaxtries      integer yes