Re: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
Am 25.06.2011 13:28, schrieb Steven Hartland:
- Original Message - From: Matthias Andree
matthias.and...@gmx.de
I'm adding back in -java as based on you comments it may well be
something in the jdk passing invalid values down to the kernel
syscall.
The socket bind works fine and the packets sent to the server arrive
and are processed by the app but when it tries to reply using
send the result is:-
java.io.IOException: Invalid argument
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:629)
using truss we see the following:-
socket(PF_INET6,SOCK_DGRAM,0)= 20 (0x14)
setsockopt(0x14,0x29,0x1b,0x7edf0318,0x4,0x0) = 0 (0x0)
setsockopt(0x14,0x,0x20,0x7edf031c,0x4,0x0) = 0 (0x0)
bind(20,{ AF_INET6 [3800::10:0:0:0]:20736 },28) = 0 (0x0)
..
sendto(20,\M^?\M^?\M^?\M^?I\aMultiplay :: ...,82,0x0,{ AF_INET6
[3800::10:0:0:0]:20736 },0x1c) ERR#22 'Invalid argument'
You're trying to send to your own address, but you're likely not using
the loopback interface for that. Is that permitted by your firewall
configuration and routing?
No I'm not its replying to the sender.
Yes you are, check your trace: The sendto address and port are the same
as the bound address.
In the java code we have:-
socket.send( new DatagramPacket( data, data.length,
src.getSocketAddress() ) );
Where src is the src packet. This works fine on IPv4 only machines and
when the jdk is told to use only IPv4 stack. So its not a problem with
the java code itself but could well be an issue with the
What data type is it?
sockstat shows it binding correctly
root java 894 21 tcp4 85.236.109.212:25675 *:*
This is unrelated, as it has fd #21 not #20 as in the socket/bind/sendto
calls. You've quoted the wrong line from sockstat output.
Oops sorry cut and paste error (wrong line) heres the correct line.
root java 894 20 udp4 85.236.109.212:25675 *:*
While a datagram socket, it does not match the socket()/bind() above.
An INET6-domain datagram socket would be listed as udp6 here. Are you
sure you're tracing the right VM and are looking at the right thread?
If so, is the incriminated traffic actually going through socket #20?
Is src.getSocketAddress() actually returning an IPv6 address?
SocketAddress is an abstract class. For my lack of Java knowledge: are
there any automatic type promotions on the Java side?
What's the Java code for binding to the socket and fetching the query
packet?
The jvm automatically sets this on all sockets for compatibility for
this exact reason. I'm not rulling out an issue with the IPv6 - v4
routing in the kernel though.
That is prohibited, so there isn't IPv6 - IPv4 routing. All IPv6
traffic remains in the IPv6 domain.
Are you sure that's what you seeing? It's not a match for what you give
above, but anyways it's an implementation artifact because the tcp code
for v4 and v6 used to be shared and the udp code separate.
Thats not how the jdk works, its ment to be 100% transparent but isn't.
You mean the JRE.
It is best to set up one IPv4 and one IPv6 listening socket.
I don't believe there is any way to do this in java it either uses the
IPv4 stack only or the IPv6 stack only hence relies on the kernel
routing IPv4 packets through the IPv6 stack.
Thats the reason the jdk explicitly enables this for all the ports it
creates, which was added as a back port of the jdk7 fixes which can
be seen here:-
http://www.freebsd.org/cgi/cvsweb.cgi/ports/java/openjdk6/files/patch-set
Check the URL above, perhaps that helps your understanding a bit. I
presume 3800::10:0:0:0 is your server?
Not that I'm aware of, here's the output from ifconfig if anyone can
tell me different, as I'm new to IPv6 and don't follow how its mapped
yet.
ifconfig
igb0: flags=8843UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST metric 0 mtu 1500
options=1bbRXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4
ether 00:25:90:2c:3c:b0
inet 85.236.109.212 netmask 0xff00 broadcast 85.236.109.255
inet6 fe80::225:90ff:fe2c:3cb0%igb0 prefixlen 64 scopeid 0x1
inet6 2001:4db0:20:2::1337 prefixlen 64nd6
The 2001:something is your local address. If you bind to 3800::
something that won't work. You couldn't bind an IPv4 address of
10.9.8.7 on this interface either.
igb1: flags=8802BROADCAST,SIMPLEX,MULTICAST metric 0 mtu 1500
options=1bbRXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4
ether 00:25:90:2c:3c:b1
media: Ethernet autoselect (1000baseSX full-duplex)
status: active
This iface has no addresses at IP level at all.
lo0: flags=8049UP,LOOPBACK,RUNNING,MULTICAST metric 0 mtu 16384
options=3RXCSUM,TXCSUM
inet 127.0.0.1 netmask 0xff00
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
Re: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
- Original Message - From: Matthias Andree matthias.and...@gmx.de No I'm not its replying to the sender. Yes you are, check your trace: The sendto address and port are the same as the bound address. This is a bug in truss it seems, Bjoern said he's gonna have a look at it. Doesn't matter what you bind to it always reports this value in the truss output. In the java code we have:- socket.send( new DatagramPacket( data, data.length, src.getSocketAddress() ) ); Where src is the src packet. This works fine on IPv4 only machines and when the jdk is told to use only IPv4 stack. So its not a problem with the java code itself but could well be an issue with the What data type is it? All mute as the Bjoern found and fixed the issue, it was a bug in the kernel fixed by:- http://svnweb.freebsd.org/base?view=revisionrevision=220463 Oops sorry cut and paste error (wrong line) heres the correct line. root java 894 20 udp4 85.236.109.212:25675 *:* While a datagram socket, it does not match the socket()/bind() above. An INET6-domain datagram socket would be listed as udp6 here. Are you sure you're tracing the right VM and are looking at the right thread? Again, truss isn't showing the correct results, confused me too ;-) Possibly another bug in sockstat / netstat as well, when the socket is a IPv6 socket bound to an IPv4 address maybe it should indicate this e.g. udp6-4 instead of either udp4 or udp6; alternatively maybe udp6 + a IPv4 address is enough to indicate this, but that could cause confusion. Thanks for looking at this, appreciated :) Regards Steve This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337 or return the E.mail to postmas...@multiplay.co.uk. ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
Just so we have pointers in the public archives: alternatives to truss are strace (in ports) and ktrace/kdump; and to obtain socket statistics, try lsof (from ports, too) possibly with -i and optionally -n and/or -P option. ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to freebsd-hackers-unsubscr...@freebsd.org
Re: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
- Original Message -
From: Matthias Andree matthias.and...@gmx.de
I'm adding back in -java as based on you comments it may well be
something in the jdk passing invalid values down to the kernel
syscall.
The socket bind works fine and the packets sent to the server arrive
and are processed by the app but when it tries to reply using
send the result is:-
java.io.IOException: Invalid argument
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:629)
using truss we see the following:-
socket(PF_INET6,SOCK_DGRAM,0)= 20 (0x14)
setsockopt(0x14,0x29,0x1b,0x7edf0318,0x4,0x0) = 0 (0x0)
setsockopt(0x14,0x,0x20,0x7edf031c,0x4,0x0) = 0 (0x0)
bind(20,{ AF_INET6 [3800::10:0:0:0]:20736 },28) = 0 (0x0)
..
sendto(20,\M^?\M^?\M^?\M^?I\aMultiplay :: ...,82,0x0,{ AF_INET6
[3800::10:0:0:0]:20736 },0x1c) ERR#22 'Invalid argument'
You're trying to send to your own address, but you're likely not using
the loopback interface for that. Is that permitted by your firewall
configuration and routing?
No I'm not its replying to the sender. In the java code we have:-
socket.send( new DatagramPacket( data, data.length, src.getSocketAddress() ) );
Where src is the src packet. This works fine on IPv4 only machines and
when the jdk is told to use only IPv4 stack. So its not a problem with
the java code itself but could well be an issue with the
sockstat shows it binding correctly
root java 894 21 tcp4 85.236.109.212:25675 *:*
This is unrelated, as it has fd #21 not #20 as in the socket/bind/sendto
calls. You've quoted the wrong line from sockstat output.
Oops sorry cut and paste error (wrong line) heres the correct line.
root java 894 20 udp4 85.236.109.212:25675 *:*
21 is the tcp port created in the same manor (ipv6 socket) which works
fine.
Note: net.inet6.ip6.v6only was set to the default 1 but changing
it to 0 has no effect on the issue.
You aren't using IPv4 mapped addresses, and you haven't stated whether
you're using wildcard listeners. Only in that case would it matter.
I'm not, its a bound port, as shown above now I have the correct line ;-)
inet6(4) reads:
IPV6CTL_V6ONLY(ip6.v6only) Boolean: enable/disable the prohib-
ited use of IPv4 mapped address on AF_INET6 sock-
ets. Defaults to on.
The jvm automatically sets this on all sockets for compatibility for
this exact reason. I'm not rulling out an issue with the IPv6 - v4
routing in the kernel though.
Are you sure that's what you seeing? It's not a match for what you give
above, but anyways it's an implementation artifact because the tcp code
for v4 and v6 used to be shared and the udp code separate.
Thats not how the jdk works, its ment to be 100% transparent but isn't.
See the following for some interesting details:-
http://diario.beerensalat.info/2008/10/12/java_and_ipv6_on_bsd.html
It is best to set up one IPv4 and one IPv6 listening socket.
I don't believe there is any way to do this in java it either uses the
IPv4 stack only or the IPv6 stack only hence relies on the kernel
routing IPv4 packets through the IPv6 stack.
Thats the reason the jdk explicitly enables this for all the ports it
creates, which was added as a back port of the jdk7 fixes which can
be seen here:-
http://www.freebsd.org/cgi/cvsweb.cgi/ports/java/openjdk6/files/patch-set
Check the URL above, perhaps that helps your understanding a bit. I
presume 3800::10:0:0:0 is your server?
Not that I'm aware of, here's the output from ifconfig if anyone can
tell me different, as I'm new to IPv6 and don't follow how its mapped
yet.
ifconfig
igb0: flags=8843UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST metric 0 mtu 1500
options=1bbRXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4
ether 00:25:90:2c:3c:b0
inet 85.236.109.212 netmask 0xff00 broadcast 85.236.109.255
inet6 fe80::225:90ff:fe2c:3cb0%igb0 prefixlen 64 scopeid 0x1
inet6 2001:4db0:20:2::1337 prefixlen 64
nd6 options=3PERFORMNUD,ACCEPT_RTADV
media: Ethernet autoselect (1000baseSX full-duplex)
status: active
igb1: flags=8802BROADCAST,SIMPLEX,MULTICAST metric 0 mtu 1500
options=1bbRXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4
ether 00:25:90:2c:3c:b1
media: Ethernet autoselect (1000baseSX full-duplex)
status: active
lo0: flags=8049UP,LOOPBACK,RUNNING,MULTICAST metric 0 mtu 16384
options=3RXCSUM,TXCSUM
inet 127.0.0.1 netmask 0xff00
inet6 ::1 prefixlen 128
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3
nd6 options=3PERFORMNUD,ACCEPT_RTADV
This is currently running on 8.2-RELEASE with openjdk6-b22_5
Regards
Steve
This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the
IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
We're trying to get our machines IPv6 enabled but in doing so this
seems to break java apps using openjdk6 for UDP sends.
The server seems quite happy to send and receive TCP packets on
IPv6 socket that are bound to IPv4 addresses, but the same is not
true for UDP.
The socket bind works fine and the packets sent to the server arrive
and are processed by the app but when it tries to reply using
send the result is:-
java.io.IOException: Invalid argument
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:629)
using truss we see the following:-
socket(PF_INET6,SOCK_DGRAM,0)= 20 (0x14)
setsockopt(0x14,0x29,0x1b,0x7edf0318,0x4,0x0) = 0 (0x0)
setsockopt(0x14,0x,0x20,0x7edf031c,0x4,0x0) = 0 (0x0)
bind(20,{ AF_INET6 [3800::10:0:0:0]:20736 },28) = 0 (0x0)
..
recvfrom(20,0x7eaeb580,1460,0x0,0x7eaed580,0x7eaed5ac) ERR#60
'Operation timed out'
..
sendto(20,\M^?\M^?\M^?\M^?I\aMultiplay :: ...,82,0x0,{ AF_INET6
[3800::10:0:0:0]:20736 },0x1c) ERR#22 'Invalid argument'
sockstat shows it binding correctly
root java 894 21 tcp4 85.236.109.212:25675 *:*
The following PR seems relevant but also seems to indicate it was
fixed back in 2006
http://www.freebsd.org/cgi/query-pr.cgi?pr=92620
Setting -Djava.net.preferIPv4Stack=true does workaround the issue
but when we come to support IPv6 as well as IPv4 this won't work.
Note: net.inet6.ip6.v6only was set to the default 1 but changing
it to 0 has no effect on the issue.
An ideas why tcp in this setup works fine for udp fails only on
send?
Not sure which list is best for this so sorry about the cross
posting.
Regards
Steve
This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it.
In the event of misdirection, illegible or incomplete transmission please
telephone +44 845 868 1337
or return the E.mail to postmas...@multiplay.co.uk.
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Re: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send
Removing -java@ list because the VM is an application on top of the
kernel's network stack, and the issue isn't Java-specific.
Am 24.06.2011 23:11, schrieb Steven Hartland:
We're trying to get our machines IPv6 enabled but in doing so this
seems to break java apps using openjdk6 for UDP sends.
The server seems quite happy to send and receive TCP packets on
IPv6 socket that are bound to IPv4 addresses, but the same is not
true for UDP.
Coincidence, and not guaranteed to work, and possibly using IPv4-mapped
IPv4 addresses (i. e. :::10.11.12.13 style).
See the v6-related sections of
http://www.freebsd.org/doc/en/books/developers-handbook/ipv6.html
The socket bind works fine and the packets sent to the server arrive
and are processed by the app but when it tries to reply using
send the result is:-
java.io.IOException: Invalid argument
at java.net.PlainDatagramSocketImpl.send(Native Method)
at java.net.DatagramSocket.send(DatagramSocket.java:629)
using truss we see the following:-
socket(PF_INET6,SOCK_DGRAM,0)= 20 (0x14)
setsockopt(0x14,0x29,0x1b,0x7edf0318,0x4,0x0) = 0 (0x0)
setsockopt(0x14,0x,0x20,0x7edf031c,0x4,0x0) = 0 (0x0)
bind(20,{ AF_INET6 [3800::10:0:0:0]:20736 },28) = 0 (0x0)
..
sendto(20,\M^?\M^?\M^?\M^?I\aMultiplay :: ...,82,0x0,{ AF_INET6
[3800::10:0:0:0]:20736 },0x1c) ERR#22 'Invalid argument'
You're trying to send to your own address, but you're likely not using
the loopback interface for that. Is that permitted by your firewall
configuration and routing?
sockstat shows it binding correctly
root java 894 21 tcp4 85.236.109.212:25675 *:*
This is unrelated, as it has fd #21 not #20 as in the socket/bind/sendto
calls. You've quoted the wrong line from sockstat output.
Note: net.inet6.ip6.v6only was set to the default 1 but changing
it to 0 has no effect on the issue.
You aren't using IPv4 mapped addresses, and you haven't stated whether
you're using wildcard listeners. Only in that case would it matter.
inet6(4) reads:
IPV6CTL_V6ONLY(ip6.v6only) Boolean: enable/disable the prohib-
ited use of IPv4 mapped address on AF_INET6 sock-
ets. Defaults to on.
An ideas why tcp in this setup works fine for udp fails only on
send?
Are you sure that's what you seeing? It's not a match for what you give
above, but anyways it's an implementation artifact because the tcp code
for v4 and v6 used to be shared and the udp code separate.
It is best to set up one IPv4 and one IPv6 listening socket.
Check the URL above, perhaps that helps your understanding a bit. I
presume 3800::10:0:0:0 is your server?
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