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tcp/dccp: warn user for preferred ip_local_port_range

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After commit 07f4c90062 ("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: David S. Miller <davem@davemloft.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-05-27 11:34:37 -07:00 committed by David S. Miller
parent e2baad9e4b
commit ed2dfd9009
2 changed files with 7 additions and 0 deletions
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1
include/net/netns/ipv4.h
View File

@ -19,6 +19,7 @@ struct sock;
struct local_ports {
seqlock_t lock;
int range[2];
bool warned;
};
struct ping_group_range {

6
net/ipv4/sysctl_net_ipv4.c
View File

@ -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);