Date: Fri, 24 Jun 2011 22:11:12 +0100 From: "Steven Hartland" <killing@multiplay.co.uk> To: <freebsd-java@freebsd.org>, <freebsd-net@freebsd.org>, <freebsd-hackers@freebsd.org> Subject: IPv4 socket bind using IPv6 socket on openjdk6 breaks udp send Message-ID: <9585F512F239475B8145C3D344F6EC62@multiplay.co.uk>
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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,0x7ffffedf0318,0x4,0x0) = 0 (0x0)
setsockopt(0x14,0xffff,0x20,0x7ffffedf031c,0x4,0x0) = 0 (0x0)
bind(20,{ AF_INET6 [3800::10:0:0:0]:20736 },28) = 0 (0x0)
..
recvfrom(20,0x7ffffeaeb580,1460,0x0,0x7ffffeaed580,0x7ffffeaed5ac) 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
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