net: increase sk_[max_]ack_backlog
sk_ack_backlog & sk_max_ack_backlog were 16bit fields, meaning
listen() backlog was limited to 65535.
It is time to increase the width to allow much bigger backlog,
if admins change /proc/sys/net/core/somaxconn &
/proc/sys/net/ipv4/tcp_max_syn_backlog default values.
Tested:
echo 5000000 >/proc/sys/net/core/somaxconn
echo 5000000 >/proc/sys/net/ipv4/tcp_max_syn_backlog
Ran a SYNFLOOD test against a listener using listen(fd, 5000000)
myhost~# grep request_sock_TCP /proc/slabinfo
request_sock_TCP 4185642 4411940 304 13 1 : tunables 54 27 8 : slabdata 339380 339380 0
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index e0360f5..3f9b8ce 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -405,8 +405,8 @@
rwlock_t sk_callback_lock;
int sk_err,
sk_err_soft;
- unsigned short sk_ack_backlog;
- unsigned short sk_max_ack_backlog;
+ u32 sk_ack_backlog;
+ u32 sk_max_ack_backlog;
__u32 sk_priority;
#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
__u32 sk_cgrp_prioidx;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 4334248..e1c85db 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -24,7 +24,6 @@
static int zero = 0;
static int one = 1;
-static int ushort_max = USHRT_MAX;
static int net_msg_warn; /* Unused, but still a sysctl */
@@ -401,7 +400,6 @@
.maxlen = sizeof(int),
.mode = 0644,
.extra1 = &zero,
- .extra2 = &ushort_max,
.proc_handler = proc_dointvec_minmax
},
{ }