From 493208b00b78463641fc179798b84a61c7c2ad72 Mon Sep 17 00:00:00 2001
From: Johannes Kimmel <fff@bareminimum.eu>
Date: Tue, 19 Jan 2021 09:07:29 +0100
Subject: [PATCH] layer3: move from fixed address to fixed hostname

Add "local.fff.community" hostname that resolves to the local router.
All possible addresses are made available to provide multiple fallbacks:
  - client ipv4 and ipv6 addresses
  - peer_ip and peer_ip6 addresses
  - fdff::1/64 on first boot and after factory reset

The moment any ipv6 network is configured, all occurrences of the
fixed fdff::/64 network are removed.

Fixes #76

Signed-off-by: Johannes Kimmel <fff@bareminimum.eu>
---
 src/packages/fff/fff-dhcp/Makefile            |  2 +-
 .../fff/fff-dhcp/files/etc/layer3.d/35-dns    | 45 +++++++++++++++++++
 .../files/etc/uci-defaults/90-fff-dhcp        |  5 +++
 src/packages/fff/fff-layer3-config/Makefile   |  2 +-
 .../files/etc/layer3.d/30-network-client      |  8 +---
 5 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/src/packages/fff/fff-dhcp/Makefile b/src/packages/fff/fff-dhcp/Makefile
index cb968948..d1507625 100644
--- a/src/packages/fff/fff-dhcp/Makefile
+++ b/src/packages/fff/fff-dhcp/Makefile
@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fff-dhcp
-PKG_RELEASE:=5
+PKG_RELEASE:=6
 
 include $(INCLUDE_DIR)/package.mk
 
diff --git a/src/packages/fff/fff-dhcp/files/etc/layer3.d/35-dns b/src/packages/fff/fff-dhcp/files/etc/layer3.d/35-dns
index ad9f1cdc..424201e9 100644
--- a/src/packages/fff/fff-dhcp/files/etc/layer3.d/35-dns
+++ b/src/packages/fff/fff-dhcp/files/etc/layer3.d/35-dns
@@ -1,3 +1,6 @@
+# load uci functions
+. /lib/functions.sh
+
 configure() {
 	## dns
 	uci -q del dhcp.@dnsmasq[0].server
@@ -10,6 +13,48 @@ configure() {
 	else
 		echo "WARNING: No DNS servers set!"
 	fi
+
+	# remove all domain autogenerated entries
+	remove_domains() {
+		local name="$1"
+
+		case $(uci -q get dhcp."$name".addedbyautoconfig) in
+			/etc/layer3.d/35-dns | /etc/uci-defaults/90-fff-dhcp)
+				uci -q del dhcp."$name" ;;
+		esac
+	}
+	config_load dhcp
+	config_foreach remove_domains domain
+
+	local dnsips
+	local have_dns=false
+
+	# gather all ips belonging to the router
+	dnsips=$(
+		uci -q batch <<- EOF | cut -d / -f1 | sort -u
+			get network.client.ip6addr
+			get network.client.ipaddr
+			get gateway.@gateway[0].peer_ip
+			get gateway.@gateway[0].peer_ip6
+		EOF
+	)
+
+	for ip in $dnsips; do
+		ip=$(echo "$ip" | cut -d / -f1)
+		case "$ip" in
+			fe80*) continue ;;
+		esac
+
+		have_dns=true
+		uci -q add dhcp domain > /dev/null
+		uci -q set dhcp.@domain[-1].ip="$ip"
+		uci -q set dhcp.@domain[-1].name="local.fff.community"
+		uci -q set dhcp.@domain[-1].addedbyautoconfig="/etc/layer3.d/35-dns"
+	done
+
+	if ! $have_dns; then
+		echo "WARNING: No valid device ip available for local DNS."
+	fi
 }
 
 apply() {
diff --git a/src/packages/fff/fff-dhcp/files/etc/uci-defaults/90-fff-dhcp b/src/packages/fff/fff-dhcp/files/etc/uci-defaults/90-fff-dhcp
index 5b59aafd..0718ba3e 100644
--- a/src/packages/fff/fff-dhcp/files/etc/uci-defaults/90-fff-dhcp
+++ b/src/packages/fff/fff-dhcp/files/etc/uci-defaults/90-fff-dhcp
@@ -27,6 +27,11 @@ uci batch >/dev/null <<EOF
   set dhcp.client=dhcp
   set dhcp.client.interface='client'
   set dhcp.client.leasetime='1h'
+
+  add dhcp domain
+  set dhcp.@domain[-1].ip="fdff::1"
+  set dhcp.@domain[-1].name="local.fff.community"
+  set dhcp.@domain[-1].addedbyautoconfig="/etc/uci-defaults/90-fff-dhcp"
 EOF
 
 uci commit dhcp
diff --git a/src/packages/fff/fff-layer3-config/Makefile b/src/packages/fff/fff-layer3-config/Makefile
index 7a7588c0..867d788b 100644
--- a/src/packages/fff/fff-layer3-config/Makefile
+++ b/src/packages/fff/fff-layer3-config/Makefile
@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fff-layer3-config
-PKG_RELEASE:=6
+PKG_RELEASE:=7
 
 include $(INCLUDE_DIR)/package.mk
 
diff --git a/src/packages/fff/fff-layer3-config/files/etc/layer3.d/30-network-client b/src/packages/fff/fff-layer3-config/files/etc/layer3.d/30-network-client
index 371846cf..551254f5 100644
--- a/src/packages/fff/fff-layer3-config/files/etc/layer3.d/30-network-client
+++ b/src/packages/fff/fff-layer3-config/files/etc/layer3.d/30-network-client
@@ -19,14 +19,10 @@ configure() {
 	uci set network.client.ip4table='fff'
 
 	# ip6addr
-	#remove old ip6addr
-	for ip in $(uci get network.client.ip6addr); do
-		if echo "$ip" | grep -v -e "fdff:" -e "fe80::1/64" > /dev/null; then
-			uci del_list network.client.ip6addr="$ip"
-		fi
-	done
 	#set new ip6addr
 	if ip6addr=$(uci -q get gateway.@client[0].ip6addr); then
+		#remove old ip6addr
+		uci delete network.client.ip6addr
 		for ip in $ip6addr; do
 			uci add_list network.client.ip6addr=$ip
 		done