Add staticIP config and fix 127.0.0.1 (#3419)

* Add staticIP config and fix 127.0.0.1

Add possibility of a staticIP config in Raspiblitz.conf to override globalIP and publicIP detection.

Skip dyndns in case of static ip usage

if curl fails accidentaly it could result in the wrong IP. Only prefer if publicIP is empty.

* add FAQ entry

Co-authored-by: rootzoll <christian@geektank.de>

FAQ.md

@@ -501,6 +501,10 @@ Yellow is OK. The RaspiBlitz can detect that it can reach a service on the port
 
 For details on how to set port forwarding on your router model see: https://portforward.com
 
+### How can I set a fixed IP?
+
+Add an entry called `staticIP` in `raspiblitz.conf` to prevent external IP detection and force a fixed IP for your node.
+
 ### How do I fix a displayed Error in my Config?
 
 When the LCD display is telling you to do a config check:

home.admin/config.scripts/internet.dyndomain.sh

@@ -47,6 +47,7 @@ fi
 # FUNCTION updating dyndomain (if update URL is set)
 updateDynDNS()
 {
+  if [ "${staticIP}" == "" ]; then
     if [ ${#dynUpdateUrl} -gt 0 ]; then
       echo "# calling: ${dynUpdateUrl}"
       echo "# to update domain: ${dynDomain}"
@@ -54,6 +55,9 @@ updateDynDNS()
     else
       echo "# dynUpdateUrl not set - not updating"
     fi
+  else
+    echo "# staticIP is set - not updating"
+  fi
 }
 
 # UPDATE

home.admin/config.scripts/internet.sh

@@ -167,9 +167,17 @@ fi
 # check for internet connection
 if [ ${runGlobal} -eq 1 ]; then
 
+  ###########################################
+  # Static IP
+  # the static IP to override globalIP and publicIP detection
+  if [ "${staticIP}" != "" ]; then
+    echo "## static IP found: ${staticIP}"
+  fi
+
   ###########################################
   # Global IP
   # the public IP that can be detected from outside
+  if [ "${staticIP}" == "" ]; then
     globalIP=""
     echo "# getting public IP from third party service"
     if [ "${ipv6}" == "on" ]; then
@@ -179,7 +187,10 @@ if [ ${runGlobal} -eq 1 ]; then
     fi
     echo "##  curl returned:  ${globalIP}"
     echo "##  curl exit code: ${?}"
-
+  else
+    globalIP=${staticIP}
+    echo "##  staticIP as globalIP: ${staticIP}"
+  fi
 
   # sanity check on IP data
   # see https://github.com/rootzoll/raspiblitz/issues/371#issuecomment-472416349
@@ -198,15 +209,25 @@ if [ ${runGlobal} -eq 1 ]; then
   if [ ${#globalIP} -eq 0 ]; then
     if [ "${ipv6}" == "on" ]; then
       globalIP="::1"
+    else
+      if [ "${staticIP}" == "" ]; then
+        # only if publicIP is empty, dont prefer 127.0.0.1
+        if [ "${publicIP}" != "" ]; then
+          globalIP="${publicIP}"
         else
           globalIP="127.0.0.1"
         fi
+      else
+        globalIP="${staticIP}"
+      fi
+    fi
   fi
 
   ##########################################
   # Public IP
-  # the public that is maybe set by raspiblitz config file (overriding aut-detection)
+  # the public that is maybe set by raspiblitz config file (overriding auto-detection)
   if [ "${publicIP}" == "" ]; then
+    if [ "${staticIP}" == "" ]; then
       # if publicIP is not set by config ... use detected global IP
       if [ "${ipv6}" == "on" ]; then
         # use ipv6 with square brackets so that it can be used in http addresses like a IPv4
@@ -214,6 +235,10 @@ if [ ${runGlobal} -eq 1 ]; then
       else
         publicIP="${globalIP}"
       fi
+    else
+      # if a static IP was set, use it as public IP
+      publicIP="${staticIP}"
+    fi
   fi
 
   ##########################################