From 8c9d3e056a6aa8aa2f67ba1b5e27015eff0e1d15 Mon Sep 17 00:00:00 2001
From: Ethan Dye <mrtops03@gmail.com>
Date: Tue, 7 Jul 2020 23:56:39 -0600
Subject: [PATCH] Fix IPv6 enabling/disabling (#1016)

The current implementation of IPv6 enabling/disabling had many issues
and could not enable IPv6 after it was disabled because of broken
functionality. This contains a simpler and fixed method to
enable/disable IPv6.

Signed-off-by: Ethan Dye <mrtops03@gmail.com>
---
 functions/openhabian.bash | 101 +++++++++-----------------------------
 includes/S90force-ipv4    |   1 +
 openhabian-setup.sh       |   2 +-
 3 files changed, 24 insertions(+), 80 deletions(-)
 create mode 100644 includes/S90force-ipv4

diff --git a/functions/openhabian.bash b/functions/openhabian.bash
index 11d2504f0..a6e7a7f7c 100644
--- a/functions/openhabian.bash
+++ b/functions/openhabian.bash
@@ -193,86 +193,29 @@ ua-netinst_check() {
   fi
 }
 
-choose_ipv6() {
-  local IPV6_DISABLE="net.ipv6.conf.all.disable_ipv6"
-
-  # shellcheck disable=SC2154
-  if [[ "$ipv6" == "disable" ]]; then
-    if ! grep -qE "^${IPV6_DISABLE}" "${SYSCTL_INIT}"; then
-      disable_ipv6 yes
-    fi
-  else
-    if [[ "$ipv6" == "enable" ]]; then
-      disable_ipv6 no
+## Enable / Disable IPv6 according to the users configured option in '$CONFIGFILE'
+##
+##    config_ipv6()
+##
+config_ipv6() {
+  local aptConf
+  local sysctlConf
+
+  aptConf="/etc/apt/apt.conf/S90force-ipv4"
+  sysctlConf="/etc/sysctl.d/99-sysctl.conf"
+
+  if [[ "${ipv6:-enable}" == "disable" ]]; then
+    echo -n "$(timestamp) [openHABian] Disabling IPv6... "
+    if ! grep -qs "^[[:space:]]*# Disable all IPv6 functionality" "$sysctlConf"; then
+      echo -e "\\n# Disable all IPv6 functionality\\nnet.ipv6.conf.all.disable_ipv6=1\\nnet.ipv6.conf.default.disable_ipv6=1\\nnet.ipv6.conf.lo.disable_ipv6=1" >> "$sysctlConf"
     fi
-  fi
-
-  sysctl -p
-}
-
-# arguments: "yes", "no"
-disable_ipv6() {
-  local APT_IPV6_DISABLE='Acquire::ForceIPv4 "true";'
-  local APT_INIT=/etc/apt/apt.conf/S90force-ipv4
-  local IPV6_DISABLE="net.ipv6.conf.all.disable_ipv6"
-  local SYSCTL_INIT="/etc/sysctl.d/99-sysctl.conf"
-
-  if [[ "$1" == "yes" ]]; then
-    echo "${APT_IPV6_DISABLE}" | sudo tee "${APT_INIT}"
-
-    if ! grep -qE "^${IPV6_DISABLE}" "${SYSCTL_INIT}"; then
-      ( echo ""
-        echo "###################################################################"
-        echo "# disable all IPv6 functionality" >> "${SYSCTL_INIT}"
-        echo "${IPV6_DISABLE}=1"
-      )	>> "${SYSCTL_INIT}"
-    else
-      sed -i "s/^# ${IPV6_ENABLE}.*/${IPV6_ENABLE}/g" "${SYSCTL_INIT}"
+    cp "${BASEDIR:-/opt/openhabian}"/includes/S90force-ipv4 "$aptConf"
+  elif [[ "${ipv6:-enable}" == "enable" ]]; then
+    echo -n "$(timestamp) [openHABian] Enabling IPv6... "
+    if grep -qs "^[[:space:]]*# Disable all IPv6 functionality" "$sysctlConf"; then
+      sed -i '/# Disable all IPv6 functionality/d; /net.ipv6.conf.all.disable_ipv6=1/d; /net.ipv6.conf.default.disable_ipv6=1/d; /net.ipv6.conf.lo.disable_ipv6=1/d' "$sysctlConf"
     fi
-  else
-    rm -f "${APT_INIT}"
-    sed -i "s/^${IPV6_ENABLE}.*/# ${IPV6_ENABLE}/g" "${SYSCTL_INIT}"
-  fi
-}
-
-choose_ipv6() {
-  local IPV6_DISABLE="net.ipv6.conf.all.disable_ipv6"
-
-  # shellcheck disable=SC2154
-  if [[ "$ipv6" == "disable" ]]; then
-    if ! grep -qE "^${IPV6_DISABLE}" "${SYSCTL_INIT}"; then
-      disable_ipv6 yes
-    fi
-  else
-    if [[ "$ipv6" == "enable" ]]; then
-      disable_ipv6 no
-    fi
-  fi
-
-  sysctl -p
-}
-
-# arguments: "yes", "no"
-disable_ipv6() {
-  local APT_IPV6_DISABLE='Acquire::ForceIPv4 "true";'
-  local APT_INIT=/etc/apt/apt.conf/S90force-ipv4
-  local IPV6_DISABLE="net.ipv6.conf.all.disable_ipv6"
-  local SYSCTL_INIT="/etc/sysctl.d/99-sysctl.conf"
-
-  if [[ "$1" == "yes" ]]; then
-    echo "${APT_IPV6_DISABLE}" | sudo tee "${APT_INIT}"
-
-    if ! grep -qE "^${IPV6_DISABLE}" "${SYSCTL_INIT}"; then
-      ( echo ""
-        echo "###################################################################"
-        echo "# disable all IPv6 functionality" >> "${SYSCTL_INIT}"
-        echo "${IPV6_DISABLE}=1"
-      )	>> "${SYSCTL_INIT}"
-    else
-      sed -i "s/^# ${IPV6_ENABLE}.*/${IPV6_ENABLE}/g" "${SYSCTL_INIT}"
-    fi
-  else
-    rm -f "${APT_INIT}"
-    sed -i "s/^${IPV6_ENABLE}.*/# ${IPV6_ENABLE}/g" "${SYSCTL_INIT}"
+    rm -f "$aptConf"
   fi
+  if cond_redirect sysctl --load; then echo "OK"; else echo "FAILED"; return 1; fi
 }
diff --git a/includes/S90force-ipv4 b/includes/S90force-ipv4
new file mode 100644
index 000000000..490ee3e22
--- /dev/null
+++ b/includes/S90force-ipv4
@@ -0,0 +1 @@
+Acquire::ForceIPv4 "true";
diff --git a/openhabian-setup.sh b/openhabian-setup.sh
index c2767773e..2323fac7e 100755
--- a/openhabian-setup.sh
+++ b/openhabian-setup.sh
@@ -77,7 +77,7 @@ for shfile in "$BASEDIR"/functions/*.bash; do source "$shfile"; done
 OLDWD=$(pwd) && cd /opt || exit 1
 
 # disable ipv6 if requested in openhabian.conf (eventually reboots)
-choose_ipv6
+config_ipv6
 
 if [[ -n "$UNATTENDED" ]]; then
   # apt/dpkg commands will not try interactive dialogs