netdev - Re: PROBLEM: Linux kernel 2.6.31 IPv4 TCP fails to open huge amount of outgoing connections (unable to bind ... )

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Date:	Wed, 21 Apr 2010 01:42:25 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Gaspar Chilingarov <gasparch@...il.com>
Cc:	netdev <netdev@...r.kernel.org>
Subject: Re: PROBLEM: Linux kernel 2.6.31 IPv4 TCP fails to open huge
 amount of outgoing connections (unable to bind ... )

Le mercredi 21 avril 2010 à 04:18 +0500, Gaspar Chilingarov a écrit :
> >
> > Its doable, only if you bind() your sockets before connect()
> >
> > For each socket, you'll need to chose an (local IP, local port) not
> > already in use.
> >
> > kernel wont magically select one source IP from the pool you have.
> >
> 
> I expect that I should select source IP and kernel should find some
> unused local_port for me.
> 
> I'm binding before the connect, of course ;)
> 
> 

Yes, you bind the IP, but let kernel choose the port.

In this case, kernel is a bit dumb (or too smart ?)

If you want to check source, its in file net/ipv4/inet_connection_sock.c

function inet_csk_get_port()

you can remove the 

if (atomic_read(&hashinfo->bsockets) > (high - low) + 1) { 
	spin_unlock(&head->lock); 
	snum = smallest_rover; 
	goto have_snum;
}

It will solve your problem (but bind() will probably be slow)



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