Date: Fri, 11 Dec 2009 00:54:12 +0300 From: pluknet <pluknet@gmail.com> To: Doug Barton <dougb@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: ping6 and a do-not-fragment option Message-ID: <a31046fc0912101354g21afe649r278d0f70095af546@mail.gmail.com> In-Reply-To: <4B21576C.7030605@FreeBSD.org> References: <20091210190305.GT45152@gerbil.cluepon.net> <4B21576C.7030605@FreeBSD.org>
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[-- Attachment #1 --]
2009/12/10 Doug Barton <dougb@freebsd.org>:
> Richard A Steenbergen wrote:
>> Hi,
>>
>> I just noticed, while trying to do a little debugging, that ping6
>> doesn't seem to have a way to specify "do not fragment" like ping does
>> for IPv4. Obviously the way this is implemented has been changed, since
>> there is no longer a DF-bit in IPv6, but it looks like there is already
>> an IPV6_DONTFRAG setsockopt() available for exactly this purpose. It
>> looks like IPV6_DONTFRAG got added at a later date (from RFC3542),
>> perhaps after ping6 was initially written.
>>
>> It seems like the correct fix would be to add a cli option to ping6
>> (perhaps 'D', since it's available and matches the command in ping) to
>> call this setsockopt() and implement a "do not fragment" option.
>>
>
> Sounds good, we look forward to reviewing your patches. :)
>
Sure, there might be compatibility issues in between KAME or something else..
--
wbr,
pluknet
[-- Attachment #2 --]
diff -urpN ping6.orig/ping6.8 ping6/ping6.8
--- ping6.orig/ping6.8 2009-12-10 23:38:37.000000000 +0300
+++ ping6/ping6.8 2009-12-11 00:18:17.000000000 +0300
@@ -40,9 +40,9 @@ packets to network hosts
.Sh SYNOPSIS
.Nm
.\" without ipsec, or new ipsec
-.Op Fl dfHmnNoqrRtvwW
+.Op Fl DdfHmnNoqrRtvwW
.\" old ipsec
-.\" .Op Fl AdEfmnNqRtvwW
+.\" .Op Fl ADdEfmnNqRtvwW
.Bk -words
.Op Fl a Ar addrtype
.Ek
@@ -141,6 +141,8 @@ Stop after sending
.Ar count
.Tn ECHO_RESPONSE
packets.
+.It Fl D
+Disable IPv6 fragmentation.
.It Fl d
Set the
.Dv SO_DEBUG
diff -urpN ping6.orig/ping6.c ping6/ping6.c
--- ping6.orig/ping6.c 2009-12-10 23:38:37.000000000 +0300
+++ ping6/ping6.c 2009-12-11 00:20:47.000000000 +0300
@@ -191,6 +191,7 @@ struct tv32 {
#define F_ONCE 0x200000
#define F_AUDIBLE 0x400000
#define F_MISSED 0x800000
+#define F_DONTFRAG 0x1000000
#define F_NOUSERDATA (F_NODEADDR | F_FQDN | F_FQDNOLD | F_SUPTYPES)
u_int options;
@@ -349,7 +350,7 @@ main(argc, argv)
#endif /*IPSEC_POLICY_IPSEC*/
#endif
while ((ch = getopt(argc, argv,
- "a:b:c:dfHg:h:I:i:l:mnNop:qrRS:s:tvwW" ADDOPTS)) != -1) {
+ "a:b:c:DdfHg:h:I:i:l:mnNop:qrRS:s:tvwW" ADDOPTS)) != -1) {
#undef ADDOPTS
switch (ch) {
case 'a':
@@ -415,6 +416,9 @@ main(argc, argv)
errx(1,
"illegal number of packets -- %s", optarg);
break;
+ case 'D':
+ options |= F_DONTFRAG;
+ break;
case 'd':
options |= F_SO_DEBUG;
break;
@@ -743,8 +747,12 @@ main(argc, argv)
*((u_int32_t *)&nonce[i]) = arc4random();
#endif
+ optval = 1;
+ if (options & F_DONTFRAG)
+ if (setsockopt(s, IPPROTO_IPV6, IPV6_DONTFRAG,
+ &optval, sizeof(optval)) == -1)
+ err(1, "IPV6_DONTFRAG");
hold = 1;
-
if (options & F_SO_DEBUG)
(void)setsockopt(s, SOL_SOCKET, SO_DEBUG, (char *)&hold,
sizeof(hold));
@@ -2780,7 +2788,7 @@ usage()
"A"
#endif
"usage: ping6 [-"
- "d"
+ "Dd"
#if defined(IPSEC) && !defined(IPSEC_POLICY_IPSEC)
"E"
#endif
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