From 8d86a09d455f06ac6b5cd46ce68c1aec480223ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <ckoenig@posteo.de>
Date: Sun, 4 Jun 2023 22:51:10 +0200
Subject: [PATCH] Check for valid OS via IPv4 and IPv6
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Christian König <ckoenig@posteo.de>
---
 advanced/Scripts/piholeDebug.sh    | 17 ++++++++++++++--
 automated install/basic-install.sh | 31 ++++++++++++++++++++++++++++--
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/advanced/Scripts/piholeDebug.sh b/advanced/Scripts/piholeDebug.sh
index ecb4fc19..b02c3dd8 100755
--- a/advanced/Scripts/piholeDebug.sh
+++ b/advanced/Scripts/piholeDebug.sh
@@ -391,7 +391,7 @@ os_check() {
     detected_os=$(grep "\bID\b" /etc/os-release | cut -d '=' -f2 | tr -d '"')
     detected_version=$(grep VERSION_ID /etc/os-release | cut -d '=' -f2 | tr -d '"')
 
-    cmdResult="$(dig +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
+    cmdResult="$(dig -4 +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
     #Get the return code of the previous command (last line)
     digReturnCode="${cmdResult##*$'\n'}"
 
@@ -401,7 +401,20 @@ os_check() {
     if [ "${digReturnCode}" -ne 0 ]; then
         log_write "${INFO} Distro: ${detected_os^}"
         log_write "${INFO} Version: ${detected_version}"
-        log_write "${CROSS} dig return code: ${COL_RED}${digReturnCode}${COL_NC}"
+        log_write "${CROSS} dig IPv4 return code: ${COL_RED}${digReturnCode}${COL_NC}"
+        log_write "${CROSS} dig response: ${response}"
+        log_write "${INFO} Retrying via IPv6"
+
+        cmdResult="$(dig -6 +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
+        #Get the return code of the previous command (last line)
+        digReturnCode="${cmdResult##*$'\n'}"
+
+        # Extract dig response
+        response="${cmdResult%%$'\n'*}"
+    fi
+    # If also no success via IPv6
+    if [ "${digReturnCode}" -ne 0 ]; then
+        log_write "${CROSS} dig IPv6 return code: ${COL_RED}${digReturnCode}${COL_NC}"
         log_write "${CROSS} dig response: ${response}"
         log_write "${CROSS} Error: ${COL_RED}dig command failed - Unable to check OS${COL_NC}"
     else
diff --git a/automated install/basic-install.sh b/automated install/basic-install.sh
index 1f3002e7..7322f4f3 100755
--- a/automated install/basic-install.sh	
+++ b/automated install/basic-install.sh	
@@ -183,7 +183,8 @@ os_check() {
         detected_os=$(grep '^ID=' /etc/os-release | cut -d '=' -f2 | tr -d '"')
         detected_version=$(grep VERSION_ID /etc/os-release | cut -d '=' -f2 | tr -d '"')
 
-        cmdResult="$(dig +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
+        # Test via IPv4
+        cmdResult="$(dig -4 +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
         # Gets the return code of the previous command (last line)
         digReturnCode="${cmdResult##*$'\n'}"
 
@@ -195,8 +196,34 @@ os_check() {
             # If the value of ${response} is a single 0, then this is the return code, not an actual response.
             if [ "${response}" == 0 ]; then
                 valid_response=false
+            else
+                valid_response=true
             fi
+        fi
+
+        # Try again via IPv6
+        if [ "$valid_response" = false ]; then
+            unset valid_response
+
+            cmdResult="$(dig -6 +short -t txt "${remote_os_domain}" @ns1.pi-hole.net 2>&1; echo $?)"
+            # Gets the return code of the previous command (last line)
+            digReturnCode="${cmdResult##*$'\n'}"
+
+            if [ ! "${digReturnCode}" == "0" ]; then
+                valid_response=false
+            else
+                # Dig returned 0 (success), so get the actual response, and loop through it to determine if the detected variables above are valid
+                response="${cmdResult%%$'\n'*}"
+                # If the value of ${response} is a single 0, then this is the return code, not an actual response.
+                if [ "${response}" == 0 ]; then
+                    valid_response=false
+                else
+                    valid_response=true
+                fi
+            fi
+        fi
 
+        if [ "$valid_response" = true ]; then
             IFS=" " read -r -a supportedOS < <(echo "${response}" | tr -d '"')
             for distro_and_versions in "${supportedOS[@]}"
             do
@@ -219,7 +246,7 @@ os_check() {
             done
         fi
 
-        if [ "$valid_os" = true ] && [ "$valid_version" = true ] && [ ! "$valid_response" = false ]; then
+        if [ "$valid_os" = true ] && [ "$valid_version" = true ] && [ "$valid_response" = true ]; then
             display_warning=false
         fi