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authorRoman Kapl <roman.kapl@sysgo.com>2017-05-24 10:22:22 +0200
committerDavid S. Miller <davem@davemloft.net>2017-05-25 19:12:17 +0200
commit7c3f1875c66fbc19762760097cabc91849ea0bbb (patch)
tree3254c77f3f02b5436ab02632a5cbfa81367b6f9a /net
parentnet: fix potential null pointer dereference (diff)
downloadlinux-7c3f1875c66fbc19762760097cabc91849ea0bbb.tar.xz
linux-7c3f1875c66fbc19762760097cabc91849ea0bbb.zip
net: move somaxconn init from sysctl code
The default value for somaxconn is set in sysctl_core_net_init(), but this function is not called when kernel is configured without CONFIG_SYSCTL. This results in the kernel not being able to accept TCP connections, because the backlog has zero size. Usually, the user ends up with: "TCP: request_sock_TCP: Possible SYN flooding on port 7. Dropping request. Check SNMP counters." If SYN cookies are not enabled the connection is rejected. Before ef547f2ac16 (tcp: remove max_qlen_log), the effects were less severe, because the backlog was always at least eight slots long. Signed-off-by: Roman Kapl <roman.kapl@sysgo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/net_namespace.c19
-rw-r--r--net/core/sysctl_net_core.c2
2 files changed, 19 insertions, 2 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 1934efd4a9d4..26bbfababff2 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -315,6 +315,25 @@ out_undo:
goto out;
}
+static int __net_init net_defaults_init_net(struct net *net)
+{
+ net->core.sysctl_somaxconn = SOMAXCONN;
+ return 0;
+}
+
+static struct pernet_operations net_defaults_ops = {
+ .init = net_defaults_init_net,
+};
+
+static __init int net_defaults_init(void)
+{
+ if (register_pernet_subsys(&net_defaults_ops))
+ panic("Cannot initialize net default settings");
+
+ return 0;
+}
+
+core_initcall(net_defaults_init);
#ifdef CONFIG_NET_NS
static struct ucounts *inc_net_namespaces(struct user_namespace *ns)
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index ea23254b2457..b7cd9aafe99e 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -479,8 +479,6 @@ static __net_init int sysctl_core_net_init(struct net *net)
{
struct ctl_table *tbl;
- net->core.sysctl_somaxconn = SOMAXCONN;
-
tbl = netns_core_table;
if (!net_eq(net, &init_net)) {
tbl = kmemdup(tbl, sizeof(netns_core_table), GFP_KERNEL);