From 057369ae1f3ad8d10b1a9e0baa5b63bc2b9087f5 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 5 Mar 2018 09:13:53 +0100
Subject: base-files: tune fragment queue thresholds for available system
 memory

The default fragment low/high thresholds are 3 and 4 MB. On devices with
only 32MB RAM, these settings may lead to OOM when many fragments that
cannot be reassembled are received. Decrease fragment low/high thresholds
to 384 and 512 kB on devices with less than 64 MB RAM.

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
---
 package/base-files/files/etc/init.d/sysctl | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

(limited to 'package/base-files/files/etc/init.d')

diff --git a/package/base-files/files/etc/init.d/sysctl b/package/base-files/files/etc/init.d/sysctl
index 3a497fb66c..65e6aa9925 100755
--- a/package/base-files/files/etc/init.d/sysctl
+++ b/package/base-files/files/etc/init.d/sysctl
@@ -3,22 +3,33 @@
 
 START=11
 
-set_vm_min_free() {
-	mem="$(grep MemTotal /proc/meminfo  | awk '{print $2}')"
+apply_defaults() {
+	local mem="$(awk '/^MemTotal:/ {print $2}' /proc/meminfo)"
+	local min_free frag_low_thresh frag_high_thresh
+
 	if [ "$mem" -gt 65536 ]; then # 128M
-		val=16384
+		min_free=16384
 	elif [ "$mem" -gt 32768 ]; then # 64M
-		val=8192
-	elif [ "$mem" -gt 16384 ]; then # 32M
-		val=1024
+		min_free=8192
 	else
-		return
+		min_free=1024
+		frag_low_thresh=393216
+		frag_high_thresh=524288
 	fi
-	sysctl -qw vm.min_free_kbytes="$val"
+
+	sysctl -qw vm.min_free_kbytes="$min_free"
+
+	[ "$frag_low_thresh" ] && sysctl -qw \
+		net.ipv4.ipfrag_low_thresh="$frag_low_thresh" \
+		net.ipv4.ipfrag_high_thresh="$frag_high_thresh" \
+		net.ipv6.ip6frag_low_thresh="$frag_low_thresh" \
+		net.ipv6.ip6frag_high_thresh="$frag_high_thresh" \
+		net.netfilter.nf_conntrack_frag6_low_thresh="$frag_low_thresh" \
+		net.netfilter.nf_conntrack_frag6_high_thresh="$frag_high_thresh"
 }
 
 start() {
-	set_vm_min_free
+	apply_defaults
 	for CONF in /etc/sysctl.conf /etc/sysctl.d/*.conf; do
 		[ -f "$CONF" ] && sysctl -p "$CONF" -e >&-
 	done
-- 
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