dhcpv6: T7807: replace wide-dhcp6c with dhcpcd

- Add a custom build of dhcpcd (to disable ipv4 and link-local address
management).
- Remove the wide-dhcpv6 build pipeline.

Author: cpcowart

.github/workflows/trigger_rebuild_packages.yml

@@ -35,6 +35,8 @@ jobs:
               - 'scripts/package-build/bash-completion/**'
             ddclient:
               - 'scripts/package-build/ddclient/**'
+            dhcpcd:
+              - 'scripts/package-build/dhcpcd/**'
             dropbear:
               - 'scripts/package-build/dropbear/**'
             ethtool:
@@ -96,8 +98,6 @@ jobs:
               - 'scripts/package-build/vpp/**'
             waagent:
               - 'scripts/package-build/waagent/**'
-            wide-dhcpv6:
-              - 'scripts/package-build/wide-dhcpv6/**'
             xen-guest-agent:
               - 'scripts/package-build/xen-guest-agent/**'
             zerotier-one:
@@ -143,6 +143,10 @@ jobs:
             trigger_build "ddclient"
           fi
 
+          if [ "${{ steps.changes.outputs.dhcpcd }}" == "true" ]; then
+            trigger_build "dhcpcd"
+          fi
+
           if [ "${{ steps.changes.outputs.dropbear }}" == "true" ]; then
             trigger_build "dropbear"
           fi
@@ -263,10 +267,6 @@ jobs:
             trigger_build "waagent"
           fi
 
-          if [ "${{ steps.changes.outputs.wide-dhcpv6 }}" == "true" ]; then
-            trigger_build "ethtool"
-          fi
-
           if [ "${{ steps.changes.outputs.xen-guest-agent }}" == "true" ]; then
             trigger_build "xen-guest-agent"
           fi

data/live-build-config/hooks/live/18-enable-disable_services.chroot

@@ -31,8 +31,8 @@ systemctl disable apt-daily.timer
 systemctl disable apt-daily-upgrade.timer
 systemctl disable apt-daily-upgrade.service
 systemctl disable chrony.service
+systemctl disable dhcpcd.service
 systemctl disable igmpproxy.service
-systemctl disable wide-dhcpv6-client.service
 systemctl disable lm-sensors.service
 systemctl disable snmpd.service
 systemctl disable conserver-server.service

scripts/package-build/dhcpcd/.gitignore

@@ -0,0 +1,6 @@
+dhcpcd/
+*.deb
+*.buildinfo
+*.changes
+*.dsc
+*.tar.*

scripts/package-build/dhcpcd/package.toml

@@ -0,0 +1,4 @@
+[[packages]]
+name = "dhcpcd"
+commit_id = "debian/1%10.1.0-11+deb13u2"
+scm_url = "https://salsa.debian.org/debian/dhcpcd.git"

scripts/package-build/dhcpcd/patches/dhcpcd/0001-configure-add-disable-lladdr-knob.patch

@@ -0,0 +1,64 @@
+Description: Add --disable-lladdr configure knob
+ When --disable-lladdr is passed, the IN6_ADDR_GEN_MODE_NONE detection
+ check is skipped, leaving HAVE_IN6_ADDR_GEN_MODE_NONE undefined.
+ The existing #ifdef HAVE_IN6_ADDR_GEN_MODE_NONE / #else structure in
+ src/ipv6.c causes CAN_ADD_LLADDR() to evaluate to 0, so
+ ipv6_tryaddlinklocal() returns early and link-local address management
+ is effectively compiled out. No changes to .c or .h files.
+Author: VyOS Package Maintainers <maintainers@vyos.net>
+Forwarded: not-needed
+Last-Update: 2026-04-29
+
+--- a/configure
++++ b/configure
+@@ -39,6 +39,7 @@ SMALL=
+ SANITIZE=no
+ STATUSARG=
+ OPENSSL=
++LLADDR=
+
+ DHCPCD_DEFS=dhcpcd-definitions.conf
+
+@@ -77,6 +78,8 @@ for x do
+ 	--enable-seccomp) SECCOMP=yes;;
+ 	--disable-ntp) NTP=no;;
+ 	--enable-ntp) NTP=yes;;
++	--disable-lladdr) LLADDR=no;;
++	--enable-lladdr) LLADDR=yes;;
+ 	--privsepuser) PRIVSEP_USER=$var;;
+ 	--prefix) PREFIX=$var;prefix=$var;; # prefix is set for autotools compat
+ 	--sysconfdir) SYSCONFDIR=$var;;
+@@ -700,21 +703,25 @@ EOF
+ 	fi
+ 	rm -f _nl80211.c _nl80211
+
+-	printf "Testing for IN6_ADDR_GEN_MODE_NONE ... "
+-	cat <<EOF >_IN6_ADDR_GEN_MODE_NONE.c
++	if [ "$LLADDR" = no ]; then
++		printf "Skipping IN6_ADDR_GEN_MODE_NONE (--disable-lladdr)\n"
++	else
++		printf "Testing for IN6_ADDR_GEN_MODE_NONE ... "
++		cat <<EOF >_IN6_ADDR_GEN_MODE_NONE.c
+ #include <linux/if_link.h>
+ int main(void) {
+ 	int x = IN6_ADDR_GEN_MODE_NONE;
+ 	return x;
+ }
+ EOF
+-	if $XCC _IN6_ADDR_GEN_MODE_NONE.c -o _IN6_ADDR_GEN_MODE_NONE 2>&3; then
+-		echo "yes"
+-		echo "#define	HAVE_IN6_ADDR_GEN_MODE_NONE" >>$CONFIG_H
+-	else
+-		echo "no"
++		if $XCC _IN6_ADDR_GEN_MODE_NONE.c -o _IN6_ADDR_GEN_MODE_NONE 2>&3; then
++			echo "yes"
++			echo "#define	HAVE_IN6_ADDR_GEN_MODE_NONE" >>$CONFIG_H
++		else
++			echo "no"
++		fi
++		rm -f _IN6_ADDR_GEN_MODE_NONE.c _IN6_ADDR_GEN_MODE_NONE
+ 	fi
+-	rm -f _IN6_ADDR_GEN_MODE_NONE.c _IN6_ADDR_GEN_MODE_NONE
+ else
+ 	printf "Testing for ifam_pid ... "
+ 	cat <<EOF >_ifam_pid.c

scripts/package-build/dhcpcd/patches/dhcpcd/0002-debian-rules-disable-ipv4-and-lladdr.patch

@@ -0,0 +1,25 @@
+Description: Pass --disable-lladdr and IPv4-related flags to configure
+ Extends the debian/rules configure invocation to pass --disable-lladdr,
+ --disable-ipv4, --disable-arp, --disable-arping, and --disable-ipv4ll.
+ The resulting VyOS dhcpcd build is IPv6-only with link-local address
+ management absent from the binary entirely.
+Author: VyOS Package Maintainers <maintainers@vyos.net>
+Forwarded: not-needed
+Last-Update: 2026-04-29
+
+--- a/debian/rules
++++ b/debian/rules
+@@ -13,7 +13,12 @@ override_dh_auto_configure:
+ 		--libexecdir=/usr/lib/dhcpcd \
+ 		--rundir=/run/dhcpcd \
+ 		--with-openssl \
+-		--with-hooks="timesyncd.conf"
++		--with-hooks="timesyncd.conf" \
++		--disable-lladdr \
++		--disable-ipv4 \
++		--disable-arp \
++		--disable-arping \
++		--disable-ipv4ll
+
+ # Avoid starting the unconfigured service as it may break connectivity.
+ override_dh_installinit: