| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: Roman Kapl <roman.kapl@sysgo.com> |
| Date: Wed, 24 May 2017 10:22:22 +0200 |
| Subject: net: move somaxconn init from sysctl code |
| |
| From: Roman Kapl <roman.kapl@sysgo.com> |
| |
| |
| [ Upstream commit 7c3f1875c66fbc19762760097cabc91849ea0bbb ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/core/net_namespace.c | 19 +++++++++++++++++++ |
| net/core/sysctl_net_core.c | 2 -- |
| 2 files changed, 19 insertions(+), 2 deletions(-) |
| |
| --- a/net/core/net_namespace.c |
| +++ b/net/core/net_namespace.c |
| @@ -312,6 +312,25 @@ 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) |
| --- a/net/core/sysctl_net_core.c |
| +++ b/net/core/sysctl_net_core.c |
| @@ -438,8 +438,6 @@ static __net_init int sysctl_core_net_in |
| { |
| 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); |