Migrate to odhcp6c for dhpcv6 client support

board/common/busybox_defconfig

@@ -1016,12 +1016,7 @@ CONFIG_UDHCPC=y
 CONFIG_FEATURE_UDHCPC_ARPING=y
 CONFIG_FEATURE_UDHCPC_SANITIZEOPT=y
 CONFIG_UDHCPC_DEFAULT_SCRIPT="/usr/share/udhcpc/default.script"
-CONFIG_UDHCPC6_DEFAULT_SCRIPT="/usr/share/udhcpc/default6.script"
-CONFIG_UDHCPC6=y
-CONFIG_FEATURE_UDHCPC6_RFC3646=y
-CONFIG_FEATURE_UDHCPC6_RFC4704=y
-CONFIG_FEATURE_UDHCPC6_RFC4833=y
-CONFIG_FEATURE_UDHCPC6_RFC5970=y
+# CONFIG_UDHCPC6 is not set
 
 #
 # Common options for DHCP applets

board/common/rootfs/usr/libexec/odhcp6c.sh

@@ -0,0 +1,242 @@
+#!/bin/sh
+# DHCPv6 client state update script for odhcp6c
+# This script expects a system with resolvconf (openresolv) and iproute2
+
+[ -z "$1" ] && echo "Error: should be called from odhcp6c" && exit 1
+
+interface="$1"
+state="$2"
+RESOLV_CONF="/run/resolvconf/interfaces/${interface}-ipv6.conf"
+NTPFILE="/run/chrony/dhcp-sources.d/${interface}-ipv6.sources"
+
+[ -n "$metric" ] || metric=5
+
+log()
+{
+	logger -I $$ -t odhcp6c -p user.notice "${interface}: $*"
+}
+
+dbg()
+{
+	logger -I $$ -t odhcp6c -p user.debug "${interface}: $*"
+}
+
+err()
+{
+	logger -I $$ -t odhcp6c -p user.err "${interface}: $*"
+}
+
+teardown_interface()
+{
+	ip -6 route flush dev "$interface"
+	ip -6 address flush dev "$interface" scope global
+}
+
+setup_interface()
+{
+	# Merge RA addresses with DHCP addresses
+	for entry in $RA_ADDRESSES; do
+		duplicate=0
+		addr="${entry%%/*}"
+		for dentry in $ADDRESSES; do
+			daddr="${dentry%%/*}"
+			[ "$addr" = "$daddr" ] && duplicate=1
+		done
+		[ "$duplicate" = "0" ] && ADDRESSES="$ADDRESSES $entry"
+	done
+
+	# Add addresses
+	for entry in $ADDRESSES; do
+		addr="${entry%%,*}"
+		entry="${entry#*,}"
+		preferred="${entry%%,*}"
+		entry="${entry#*,}"
+		valid="${entry%%,*}"
+
+		ip -6 address add "$addr" dev "$interface" preferred_lft "$preferred" valid_lft "$valid" proto dhcp
+		log "assigned address $addr (preferred=$preferred, valid=$valid)"
+	done
+
+	# Add routes from RA
+	for entry in $RA_ROUTES; do
+		addr="${entry%%,*}"
+		entry="${entry#*,}"
+		gw="${entry%%,*}"
+		entry="${entry#*,}"
+		valid="${entry%%,*}"
+		entry="${entry#*,}"
+		metric="${entry%%,*}"
+
+		if [ -n "$gw" ]; then
+			ip -6 route add "$addr" via "$gw" metric "$metric" dev "$interface" from "::/128"
+		else
+			ip -6 route add "$addr" metric "$metric" dev "$interface"
+		fi
+
+		# Add routes for delegated prefixes
+		for prefix in $PREFIXES; do
+			paddr="${prefix%%,*}"
+			[ -n "$gw" ] && ip -6 route add "$addr" via "$gw" metric "$metric" dev "$interface" from "$paddr"
+		done
+	done
+}
+
+handle_prefixes()
+{
+	# $PREFIXES format: "prefix/len,preferred,valid[,class=N][,excluded=...] ..."
+	for entry in $PREFIXES; do
+		addr="${entry%%,*}"
+		entry="${entry#*,}"
+		preferred="${entry%%,*}"
+		entry="${entry#*,}"
+		valid="${entry%%,*}"
+
+		log "received delegated prefix $addr (preferred=$preferred, valid=$valid)"
+
+		# Add unreachable route to prevent routing loops
+		ip -6 route add unreachable "$addr" 2>/dev/null
+
+		# Future: Distribute to downstream interfaces
+	done
+}
+
+handle_dns()
+{
+	truncate -s 0 "$RESOLV_CONF"
+
+	# Combine DHCPv6 DNS ($RDNSS) and RA DNS ($RA_DNS), deduplicating
+	all_dns=""
+	for server in $RDNSS $RA_DNS; do
+		# Simple deduplication: only add if not already in list
+		case " $all_dns " in
+			*" $server "*) ;;
+			*) all_dns="$all_dns $server" ;;
+		esac
+	done
+
+	# Domain search list (DHCPv6 option 24)
+	if [ -n "$DOMAINS" ]; then
+		dbg "adding search domains: $DOMAINS"
+		echo "search $DOMAINS # $interface" >> "$RESOLV_CONF"
+	fi
+
+	# DNS servers
+	for server in $all_dns; do
+		[ -z "$server" ] && continue
+		dbg "adding dns $server"
+		echo "nameserver $server # $interface" >> "$RESOLV_CONF"
+	done
+
+	if [ -n "$all_dns" ]; then
+		resolvconf -u
+	fi
+}
+
+handle_ntp()
+{
+	# DHCPv6 option 56 (NTP server) is provided as $OPTION_56 in hex format
+	# Format: sub-option-code (2 bytes) + length (2 bytes) + data
+	# Sub-option 1 = NTP server address (16 bytes IPv6)
+	#
+	# This is complex to parse in shell. For now, we attempt basic parsing
+	# and fall back to logging a warning if the format is unexpected.
+
+	if [ -n "$OPTION_56" ]; then
+		# Remove all non-hex characters (spaces, colons, etc.) and convert to lowercase
+		hex=$(echo "$OPTION_56" | tr -d '[:space:]:-' | tr '[:upper:]' '[:lower:]')
+
+		truncate -s 0 "$NTPFILE"
+		ntp_found=0
+
+		# Parse option 56: iterate through sub-options
+		# Each sub-option: 2 bytes code + 2 bytes length + data
+		pos=0
+		while [ $pos -lt ${#hex} ]; do
+			# Need at least 4 hex chars (2 bytes) for sub-option code
+			[ $((${#hex} - pos)) -lt 4 ] && break
+
+			# Extract sub-option code (2 bytes = 4 hex chars)
+			subopt_code=$(echo "$hex" | cut -c $((pos+1))-$((pos+4)))
+			pos=$((pos + 4))
+
+			# Need 4 more hex chars for length
+			[ $((${#hex} - pos)) -lt 4 ] && break
+
+			# Extract length (2 bytes = 4 hex chars)
+			subopt_len_hex=$(echo "$hex" | cut -c $((pos+1))-$((pos+4)))
+			subopt_len=$(printf "%d" "0x$subopt_len_hex")
+			pos=$((pos + 4))
+
+			# Sub-option 1 = NTP server address (should be 16 bytes for IPv6)
+			if [ "$subopt_code" = "0001" ] && [ "$subopt_len" -eq 16 ]; then
+				# Extract 16 bytes (32 hex chars) for IPv6 address
+				addr_hex=$(echo "$hex" | cut -c $((pos+1))-$((pos+32)))
+
+				# Convert hex to IPv6 address format
+				# Format: 0123456789abcdef0123456789abcdef -> 0123:4567:89ab:cdef:0123:4567:89ab:cdef
+				ipv6=$(echo "$addr_hex" | sed 's/\(....\)\(....\)\(....\)\(....\)\(....\)\(....\)\(....\)\(....\)/\1:\2:\3:\4:\5:\6:\7:\8/')
+
+				dbg "got NTP server $ipv6"
+				echo "server $ipv6 iburst" >> "$NTPFILE"
+				ntp_found=1
+			fi
+
+			# Skip this sub-option's data
+			pos=$((pos + subopt_len * 2))
+		done
+
+		if [ "$ntp_found" -eq 1 ]; then
+			chronyc reload sources >/dev/null 2>&1
+		else
+			dbg "option 56 received but no NTP server addresses found (consider using option 31/SNTP)"
+		fi
+	fi
+}
+
+log "state: $state"
+
+(
+	flock 9
+	case "$state" in
+		started)
+			# Initial state - clean up any stale config
+			teardown_interface
+			;;
+
+		bound)
+			# Fresh lease - tear down and set up from scratch
+			teardown_interface
+			setup_interface
+			handle_prefixes
+			handle_dns
+			handle_ntp
+			;;
+
+		informed|updated|rebound|ra-updated)
+			# Update existing configuration
+			setup_interface
+			[ -n "$PREFIXES" ] && handle_prefixes
+			handle_dns
+			handle_ntp
+			;;
+
+		unbound|stopped)
+			# Lost server or client stopped
+			teardown_interface
+			rm -f "$RESOLV_CONF"
+			rm -f "$NTPFILE"
+			resolvconf -u
+			chronyc reload sources >/dev/null 2>&1
+			;;
+	esac
+) 9>/tmp/odhcp6c.lock.${interface}
+rm -f /tmp/odhcp6c.lock.${interface}
+
+# Run hooks
+HOOK_DIR="/usr/libexec/odhcp6c.d"
+for hook in "${HOOK_DIR}/"*; do
+	[ -f "${hook}" -a -x "${hook}" ] || continue
+	"${hook}" "$interface" "$state"
+done
+
+exit 0

configs/aarch32_defconfig

@@ -35,6 +35,7 @@ BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="${BR2_EXTERNAL_INFIX_PATH}/board/aarch32/li
 BR2_LINUX_KERNEL_INSTALL_TARGET=y
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
 BR2_PACKAGE_BUSYBOX_CONFIG="${BR2_EXTERNAL_INFIX_PATH}/board/common/busybox_defconfig"
+BR2_PACKAGE_ODHCP6C=y
 BR2_PACKAGE_STRACE=y
 BR2_PACKAGE_STRESS_NG=y
 BR2_PACKAGE_JQ=y

configs/aarch32_minimal_defconfig

@@ -35,6 +35,7 @@ BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="${BR2_EXTERNAL_INFIX_PATH}/board/aarch32/li
 BR2_LINUX_KERNEL_INSTALL_TARGET=y
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
 BR2_PACKAGE_BUSYBOX_CONFIG="${BR2_EXTERNAL_INFIX_PATH}/board/common/busybox_defconfig"
+BR2_PACKAGE_ODHCP6C=y
 BR2_PACKAGE_STRACE=y
 BR2_PACKAGE_STRESS_NG=y
 BR2_PACKAGE_JQ=y

configs/aarch64_defconfig

@@ -32,6 +32,7 @@ BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="${BR2_EXTERNAL_INFIX_PATH}/board/aarch64/linux_defconfig"
 BR2_LINUX_KERNEL_INSTALL_TARGET=y
 BR2_PACKAGE_BUSYBOX_CONFIG="${BR2_EXTERNAL_INFIX_PATH}/board/common/busybox_defconfig"
+BR2_PACKAGE_ODHCP6C=y
 BR2_PACKAGE_STRACE=y
 BR2_PACKAGE_STRESS_NG=y
 BR2_PACKAGE_JQ=y