[openwrt/openwrt] netifd: use stable IAID for DHCPv4

[LEDE Commits]

noltari pushed a commit to openwrt/openwrt.git, branch openwrt-25.12:
https://git.openwrt.org/88f97a96491cb0a62398752cb5901d37aff2f147

commit 88f97a96491cb0a62398752cb5901d37aff2f147
Author: Álvaro Fernández Rojas <noltari at gmail.com>
AuthorDate: Sat Jan 10 15:44:48 2026 +0100

    netifd: use stable IAID for DHCPv4
    
    Commit 9151c7015ed2 introduced support for the global DHCP DUID to
    generate a RFC4361-style client identifier.
    However, the IAID introduced in those changes is based on ifindex, which
    is subject to changes and causes issues on environments requiring a stable
    IAID.
    
    This commit switches the IAID to a stable one based on MD5.
    
    (cherry picked from commit e1c125c167e5c4fef16fd5e2bf670f290808b2d1)
    Fixes: 9151c7015ed2 ("netifd: use the global DHCP DUID for DHCPv4")
    Link: https://github.com/openwrt/openwrt/pull/21489
    Signed-off-by: Álvaro Fernández Rojas <noltari at gmail.com>
---
 package/network/config/netifd/Makefile                       | 2 +-
 package/network/config/netifd/files/lib/netifd/proto/dhcp.sh | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/package/network/config/netifd/Makefile b/package/network/config/netifd/Makefile
index 2c550ef554..a66f87d38d 100644
--- a/package/network/config/netifd/Makefile
+++ b/package/network/config/netifd/Makefile
@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=netifd
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/netifd.git
diff --git a/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh b/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
index 1c0f720f4a..e5724ff11f 100755
--- a/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
+++ b/package/network/config/netifd/files/lib/netifd/proto/dhcp.sh
@@ -3,6 +3,7 @@
 [ -x /sbin/udhcpc ] || exit 0
 
 . /lib/functions.sh
+. /lib/functions/network.sh
 . ../netifd-proto.sh
 . /lib/config/uci.sh
 init_proto "$@"
@@ -37,11 +38,11 @@ proto_dhcp_get_default_clientid() {
 
 	local iface="$1"
 	local duid
-	local iaid="0"
+	local iaid
 
-        [ -e "/sys/class/net/$iface/ifindex" ] && iaid="$(cat "/sys/class/net/$iface/ifindex")"
-        duid="$(uci_get network @globals[0] dhcp_default_duid)"
-        [ -n "$duid" ] && printf "ff%08x%s" "$iaid" "$duid"
+	network_generate_iface_iaid iaid "$iface"
+	duid="$(uci_get network @globals[0] dhcp_default_duid)"
+	[ -n "$duid" ] && printf "ff%s%s" "$iaid" "$duid"
 }
 
 proto_dhcp_setup() {