script: support IPv6 in simhostroute.sh

1. Change IP address format to addr/prefix, to be compatible with both IPv4/IPv6.
   - When adding address in CIDR type, netmask/route will be automatically added.
2. Since route of whole subnet is added automatically, not specifying NuttX's IP any more.
   - Multiple NuttX simulators (with IP 10.0.1.x) attached to same bridge can surf the net at same time.
3. NAT66 is used to make sure it works even if host has only one IPv6 address.

Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>

boards/sim/sim/sim/NETWORK-LINUX.txt

@@ -59,7 +59,9 @@ On Linux:
 
 On the NuttX Simulator:
 
-    nsh> ifconfig eth0 10.0.1.2
+    nsh> # replace or omit dns if needed, IPv6 line is optional
+    nsh> ifconfig eth0 inet6 fc00::2/112 dns 2001:4860:4860::8888
+    nsh> ifconfig eth0 10.0.1.2 dns 8.8.8.8
     nsh> ifup eth0
 
 On Linux:

tools/netusb.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 #****************************************************************************
-# tools/simhostroute.sh
+# tools/netusb.sh
 #
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with

tools/simhostroute.sh

@@ -40,43 +40,65 @@ IF_HOST=$1
 STATUS=$2
 
 IF_BRIDGE=nuttx0
-IP_NET="10.0.1.0/24"
+IPv4_HOST="10.0.1.1/24"
-IP_NETMASK="255.255.255.0"
+IPv6_HOST="fc00::1/112"
-IP_BROADCAST="10.0.0.255"
+IPv6_ENABLE=true
-IP_HOST="10.0.1.1"
+
-IP_NUTTX="10.0.1.2"
+call_all() {
+  FUNC=$1
+
+  IPTABLES="iptables"
+  IP_HOST=$IPv4_HOST
+
+  # call function
+  $FUNC
+
+  # enable forward to make sure nat works
+  sysctl -w net.ipv4.ip_forward=1
+
+  if [ "$IPv6_ENABLE" == "true" ]; then
+    IPTABLES="ip6tables"
+    IP_HOST=$IPv6_HOST
+
+    # call function
+    $FUNC
+
+    # enable forward to make sure nat works
+    sysctl -w net.ipv6.conf.all.forwarding=1
+  fi
+}
+
+net_on() {
+  # add address to the bridge, with CIDR specified, netmask/route will be automatically added.
+  ip addr add $IP_HOST dev $IF_BRIDGE
+
+  # nat to allow NuttX to access the internet
+  $IPTABLES -t nat -A POSTROUTING -o $IF_HOST -j MASQUERADE
+  $IPTABLES -A FORWARD -i $IF_HOST -o $IF_BRIDGE -m state --state RELATED,ESTABLISHED -j ACCEPT
+  $IPTABLES -A FORWARD -i $IF_BRIDGE -o $IF_HOST -j ACCEPT
+}
+
+net_off() {
+  ip addr del $IP_HOST dev $IF_BRIDGE
+
+  # delete nat rules to clean up
+  $IPTABLES -t nat -D POSTROUTING -o $IF_HOST -j MASQUERADE
+  $IPTABLES -D FORWARD -i $IF_HOST -o $IF_BRIDGE -m state --state RELATED,ESTABLISHED -j ACCEPT
+  $IPTABLES -D FORWARD -i $IF_BRIDGE -o $IF_HOST -j ACCEPT
+}
+
+# remove all configs first to avoid double configure
+call_all net_off
 
 if [ "$STATUS" == "on" ]; then
     ip link add $IF_BRIDGE type bridge
-    ifconfig $IF_BRIDGE $IP_HOST
     ifconfig $IF_BRIDGE up
     ifconfig -a
-    ip addr add $IP_HOST dev $IF_BRIDGE
-    ifconfig $IF_BRIDGE netmask $IP_NETMASK
-    ip route delete $IP_NET
-    ip route add $IP_NET dev $IF_BRIDGE src $IP_HOST
-    ip route add $IP_NUTTX/32 dev $IF_BRIDGE src $IP_HOST
 
-    # nat to allow NuttX to access the internet
+    call_all net_on
-    iptables -t nat -A POSTROUTING -o $IF_HOST -j MASQUERADE
-    iptables -A FORWARD -i $IF_HOST -o $IF_BRIDGE -m state --state RELATED,ESTABLISHED -j ACCEPT
-    iptables -A FORWARD -i $IF_BRIDGE -o $IF_HOST -j ACCEPT
-
-    # enable forward to make sure nat works
-    sysctl -w net.ipv4.ip_forward=1
-
-    ip route show
 else
-    ip route delete $IP_NET
-    ip route delete $IP_NUTTX/32
-
-    # delete nat rules to clean up
-    iptables -t nat -D POSTROUTING -o $IF_HOST -j MASQUERADE
-    iptables -D FORWARD -i $IF_HOST -o $IF_BRIDGE -m state --state RELATED,ESTABLISHED -j ACCEPT
-    iptables -D FORWARD -i $IF_BRIDGE -o $IF_HOST -j ACCEPT
-
     ip link delete $IF_BRIDGE type bridge
-
-    ip route show
 fi
 
+ip route show
+ip -6 route show