From: Eric Dumazet <eduma...@google.com>
After commit 07f4c90062f8f ("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 <da...@davemloft.net>
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
include/net/netns/ipv4.h | 1 +
net/ipv4/sysctl_net_ipv4.c | 6 ++++++
2 files changed, 7 insertions(+)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index
6848b8bb2e6319ac9ddd90dd45b39eb01c6c9ff8..c68926b4899c36e77c38b6244dfb8d126685b905
100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -19,6 +19,7 @@ struct sock;
struct local_ports {
seqlock_t lock;
int range[2];
+ bool warned;
};
struct ping_group_range {
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index
e64892769607a6089e10d5c9e63dc3564c983341..708861046c6131736d8931ecfca421a629146a50
100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -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);
--
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