From 60cc5d98f595aa932576a42c1cd249d68ab493dc Mon Sep 17 00:00:00 2001
From: "Rick Farina (Zero_Chaos)" <zerochaos@gentoo.org>
Date: Thu, 12 Dec 2019 14:14:31 -0500
Subject: [PATCH] introduce netmode auto

who wouldn't want a sweet feature like this?
---
 usr/bin/NETMODE | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/usr/bin/NETMODE b/usr/bin/NETMODE
index a056b41..1a83f51 100755
--- a/usr/bin/NETMODE
+++ b/usr/bin/NETMODE
@@ -5,14 +5,35 @@ function show_usage() {
     echo ""
 }
 
+function configure_client() {
+    /etc/init.d/odhcpd stop
+    uci set network.lan.proto='dhcp'
+}
+
+function configure_server() {
+    uci set network.lan.proto='none'
+    /etc/init.d/odhcpd start
+}
+
 case $1 in
     "DHCP_CLIENT")
-        uci set network.lan.proto='dhcp'
-        /etc/init.d/odhcpd stop
+        configure_client
         ;;
     "DHCP_SERVER")
-        uci set network.lan.proto='none'
-        /etc/init.d/odhcpd start
+        configure_server
+        ;;
+    "AUTO")
+        #make sure nothing interferes
+        /etc/init.d/odhcpd stop
+        /etc/init.d/network stop
+        #this will exit 0 if a dhcp related packet is seen, and 124 if not
+        #todo: this only looks for a dhcp request/discover and doesn't check that there was no reply...
+        if timeout 10 tcpdump -Z nobody -i eth0 -c 1 -q udp src port 68 > /dev/null 2>&1; then
+            #we saw someone looking for a dhcp server
+            configure_server
+        else
+            configure_client
+        fi
         ;;
     *)
         show_usage