From f7cb0f2f0015733751a40b901bf5077dfd8ac992 Mon Sep 17 00:00:00 2001
From: bergware <bergware@users.noreply.github.com>
Date: Fri, 1 Nov 2024 21:47:05 +0100
Subject: [PATCH] NTP enhancements

- Add new parameter "NTP interval", this can be useful when you run your own NTP servers
- Add pool support, this allows a round-robin selection of NTP servers out of a pool, and improves server availability
---
 emhttp/plugins/dynamix/DateTime.page       | 10 +++++++++
 emhttp/plugins/dynamix/sheets/DateTime.css |  1 +
 etc/rc.d/rc.ntpd                           | 24 +++++++++++++++++-----
 3 files changed, 30 insertions(+), 5 deletions(-)
 create mode 100644 emhttp/plugins/dynamix/sheets/DateTime.css

diff --git a/emhttp/plugins/dynamix/DateTime.page b/emhttp/plugins/dynamix/DateTime.page
index d7fdaae60..3c1c13f5a 100644
--- a/emhttp/plugins/dynamix/DateTime.page
+++ b/emhttp/plugins/dynamix/DateTime.page
@@ -59,6 +59,14 @@ _(Use NTP)_:
 
 :use_ntp_help:
 
+_(NTP interval)_:
+: <select name="display_ntppoll">
+  <?=mk_option(_var($display,'ntppoll'), "", _('Default'))?>
+  <?=mk_option(_var($display,'ntppoll'), "8", _('Slow'))?>
+  <?=mk_option(_var($display,'ntppoll'), "5", _('Medium'))?>
+  <?=mk_option(_var($display,'ntppoll'), "3", _('Fast'))?>
+  </select><span class="ntp orange-text">_(Use DEFAULT setting when public NTP servers are defined)_</span>
+
 _(NTP server)_ 1:
 : <input type="text" name="NTP_SERVER1" maxlength="40" class="narrow" value="<?=htmlspecialchars($var['NTP_SERVER1'])?>">
 
@@ -107,12 +115,14 @@ function presetTime(form) {
 function checkDateTimeSettings(form) {
   if (form.USE_NTP.value=="yes") {
     form.newDateTime.disabled=true;
+    form.display_ntppoll.disabled=false;
     form.NTP_SERVER1.disabled=false;
     form.NTP_SERVER2.disabled=false;
     form.NTP_SERVER3.disabled=false;
     form.NTP_SERVER4.disabled=false;
   } else {
     form.newDateTime.disabled=false;
+    form.display_ntppoll.disabled=true;
     form.NTP_SERVER1.disabled=true;
     form.NTP_SERVER2.disabled=true;
     form.NTP_SERVER3.disabled=true;
diff --git a/emhttp/plugins/dynamix/sheets/DateTime.css b/emhttp/plugins/dynamix/sheets/DateTime.css
new file mode 100644
index 000000000..b2eb5cbbe
--- /dev/null
+++ b/emhttp/plugins/dynamix/sheets/DateTime.css
@@ -0,0 +1 @@
+span.ntp{margin-left:40px}
diff --git a/etc/rc.d/rc.ntpd b/etc/rc.d/rc.ntpd
index 75f76c146..deedfedc9 100755
--- a/etc/rc.d/rc.ntpd
+++ b/etc/rc.d/rc.ntpd
@@ -13,6 +13,7 @@ NTPD="/usr/sbin/ntpd"
 OPTIONS="-g -u ntp:ntp"
 CONF="/etc/ntp.conf"
 IDENT="/boot/config/ident.cfg"
+CONFIG="/boot/config/plugins/dynamix/dynamix.cfg"
 
 # run & log functions
 . /etc/rc.d/rc.runlog
@@ -38,11 +39,24 @@ ntpd_build(){
       echo "interface listen $NET" >>$CONF
     done
   fi
-  # add configured NTP servers
-  [[ -n $NTP_SERVER1 ]] && echo "server $NTP_SERVER1 iburst" >>$CONF
-  [[ -n $NTP_SERVER2 ]] && echo "server $NTP_SERVER2 iburst" >>$CONF
-  [[ -n $NTP_SERVER3 ]] && echo "server $NTP_SERVER3 iburst" >>$CONF
-  [[ -n $NTP_SERVER4 ]] && echo "server $NTP_SERVER4 iburst" >>$CONF
+  # ntp poll interval may be adjusted to predefined values
+  if [[ -f $CONFIG ]]; then
+    NTP_POLL=$(grep -Po '^ntppoll="\K[^"]+' $CONFIG)
+    if [[ -n $NTP_POLL ]]; then
+      MINPOLL="minpoll $NTP_POLL"
+      MAXPOLL="maxpoll $NTP_POLL"
+    fi
+  fi
+  # add configured ntp servers or pools
+  for n in {1..4}; do
+    NTP="NTP_SERVER$n"
+    if [[ -n ${!NTP} ]]; then
+      # use either server or pool peers depending on remote ntp name
+      # pools use a round-robin mechanism to get a server out of the pool
+      [[ ${!NTP} =~ "pool" ]] && PEER=pool || PEER=server
+      echo "$PEER ${!NTP} iburst $MINPOLL $MAXPOLL" >>$CONF
+    fi
+  done
 }
 
 ntpd_start(){