From b8b25dcd62252829c8faacfb049193eae161a06f Mon Sep 17 00:00:00 2001
From: "D. Berge" <dberge@aaltronav.eu>
Date: Sat, 9 Aug 2025 22:23:50 +0200
Subject: [PATCH] Update IP getter script to return LAN address.

get-ip.sh internet: returns the first IP address found that has
internet access.

get-ip.sh local (or no argument): returns the list of non-loopback
IPs minus the one that has internet access.

This means that update-dns.sh now sends the first IP address that
does *not* have internet access.
---
 sbin/get-ip.sh     | 53 +++++++++++++++++++++++++++++++++-------------
 sbin/update-dns.sh |  2 +-
 2 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/sbin/get-ip.sh b/sbin/get-ip.sh
index 77c4510..34d4669 100755
--- a/sbin/get-ip.sh
+++ b/sbin/get-ip.sh
@@ -1,19 +1,42 @@
 #!/bin/bash
 
-# Find the interface used for the default route (e.g., to reach 8.8.8.8)
-INTERFACE=$(ip route get 8.8.8.8 | awk '{for(i=1;i<=NF;i++) if ($i=="dev") {print $(i+1); exit}}')
+# Function to get the internet IP
+get_internet_ip() {
+    INTERFACE=$(ip route get 8.8.8.8 2>/dev/null | awk '{for(i=1;i<=NF;i++) if ($i=="dev") {print $(i+1); exit}}')
 
-if [ -z "$INTERFACE" ] || [ "$INTERFACE" = "lo" ]; then
-    echo "No valid default route found." >/dev/stderr
-    exit 1
+    if [ -z "$INTERFACE" ] || [ "$INTERFACE" = "lo" ]; then
+        return 1
+    fi
+
+    IP=$(ip -4 addr show dev "$INTERFACE" scope global | grep -oP '(?<=inet\s)\d{1,3}(\.\d{1,3}){3}(?=/)' | head -n1)
+
+    if [ -z "$IP" ]; then
+        return 1
+    fi
+
+    echo "$IP"
+    return 0
+}
+
+# Get all global non-loopback IPv4 addresses
+ALL_IPS=$(ip -4 addr show scope global | grep -oP '(?<=inet\s)\d{1,3}(\.\d{1,3}){3}(?=/)')
+
+ARG="${1:-local}"
+
+if [ "$ARG" = "internet" ]; then
+    INTERNET_IP=$(get_internet_ip)
+    if [ $? -ne 0 ]; then
+        echo "No valid default route or global IPv4 address found."
+        exit 1
+    fi
+    echo "$INTERNET_IP"
+else
+    # For "local" or anything else
+    INTERNET_IP=$(get_internet_ip) || INTERNET_IP=""  # If fails, set to empty so no exclusion
+
+    for IP in $ALL_IPS; do
+        if [ "$IP" != "$INTERNET_IP" ]; then
+            echo "$IP"
+        fi
+    done
 fi
-
-# Extract the primary IPv4 address from the interface (excluding loopback)
-IP=$(ip -4 addr show dev "$INTERFACE" scope global | grep -oP '(?<=inet\s)\d{1,3}(\.\d{1,3}){3}(?=/)' | head -n1)
-
-if [ -z "$IP" ]; then
-    echo "No global IPv4 address found on $INTERFACE." >/dev/stderr
-    exit 1
-fi
-
-echo "$IP"
diff --git a/sbin/update-dns.sh b/sbin/update-dns.sh
index 088bddf..9bce061 100755
--- a/sbin/update-dns.sh
+++ b/sbin/update-dns.sh
@@ -16,7 +16,7 @@ fi
 IP_SCRIPT="$HOME/software/sbin/get-ip.sh"
 
 # Get the current IPv4 address
-IP_ADDRESS=$("$IP_SCRIPT")
+IP_ADDRESS=$("$IP_SCRIPT" |head -n1)
 
 if [ -z "$IP_ADDRESS" ]; then
   echo "Error: Failed to retrieve IP address from $IP_SCRIPT"