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Commit ed2dfd90 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp/dccp: warn user for preferred ip_local_port_range 



After commit 07f4c900 ("tcp/dccp: try to not exhaust
ip_local_port_range in connect()") it is advised to have an even number
of ports described in /proc/sys/net/ipv4/ip_local_port_range

This means start/end values should have a different parity.

Let's warn sysadmins of this, so that they can update their settings
if they want to.

Suggested-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e2baad9e

include/net/netns/ipv4.h

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ struct sock; 
struct local_ports {

	seqlock_t	lock;

	int		range[2];

	bool		warned;

};



struct ping_group_range {

net/ipv4/sysctl_net_ipv4.c

+6 −0
Original line number Diff line number Diff line
@@ -45,7 +45,13 @@ static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX }; 
/* Update system visible IP port range */

static void set_local_port_range(struct net *net, int range[2])

{

	bool same_parity = !((range[0] ^ range[1]) & 1);



	write_seqlock(&net->ipv4.ip_local_ports.lock);

	if (same_parity && !net->ipv4.ip_local_ports.warned) {

		net->ipv4.ip_local_ports.warned = true;

		pr_err_ratelimited("ip_local_port_range: prefer different parity for start/end values.\n");

	}

	net->ipv4.ip_local_ports.range[0] = range[0];

	net->ipv4.ip_local_ports.range[1] = range[1];

	write_sequnlock(&net->ipv4.ip_local_ports.lock);