[jboss-jira] [JBoss JIRA] (JGRP-1880) UDP.ip_ttl is ignored and is always 1

[Bela Ban (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13006051#comment-13006051 ] 

Bela Ban edited comment on JGRP-1880 at 9/25/14 8:36 AM:
---------------------------------------------------------

I found out that the DatagramSocket returned via {{DatagramChannel.socket()}} has a stupid readLock / writeLock held when calling {{receive()}} or {{send()}} respectively. This means that the unicast receiver in TP will block until unicast messages are received, but this will also keep the _sender_ from sending any data !
Very stupid and breaking the semantics of {{DatagramSocket.send()}} which allows for concurrent receiving and sending as there's no readLock or writeLock, but synchronization is done on the DatagramPacket only.
I don't really want to use 2 separate unicast sockets now; one for receiving unicasts and one for sending unicasts. More investigation needed...


was (Author: belaban):
I found out that the DatagramSocket returned via {{DatagramChannel.socket()}} has a stupid readLock / writeLock held when calling {{receive()}} or {{send()}} respectively. This means that the unicast receiver in TP will block until unicast messages are received, but this will also keep the _sender_ from sending any data !
Very stupid and breaking the semantics of {{DatagramSocket.send()}} which allows for concurrent receiving and sending as there's no readLock or writeLock, but synchronization is done on the DatagramPacket only.
I don't really want to use 2 separate unicast sockets now; one for receiving unicasts and one for sending unicasts. More investigate needed...

> UDP.ip_ttl is ignored and is always 1
> -------------------------------------
>
>                 Key: JGRP-1880
>                 URL: https://issues.jboss.org/browse/JGRP-1880
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.6
>
>
> Since we switched from using a {{MulticastSocket}} for sending of multicast packets to a {{DatagramSocket}}, the time-to-live (TTL) of a packet is always {{1}}. The reason is that method {{setTimeToLive()}} only exists in {{MulticastSocket}}, but not in {{DatagramSocket}}.
> We cannot revert the code and use a {{MulticastSocket}} to send multicasts, as this won't reveal the real IP address of the sender, but only the multicast address, and the real address is needed to drop packets at the _transport level_.
> Investigate whether we could use reflection to get the {{DatagramSocketImpl}} and call {{setTimeToLive()}}.



--
This message was sent by Atlassian JIRA
(v6.3.1#6329)