busybox: udhcpc: fix 'ip route add' with multiple interfaces on the same network

The udhcpc script fails to properly set a default route when:

 - 'ip' is present ($have_bin_ip -eq 1)
 - there are 2 or more interfaces connected to the same network
   (e.g. ethernet + wifi on the same home LAN / same DHCP server)

In this case, when the first interface gets an address from DHCP
(e.g. eth0), a default route is set correctly. When the second interface
(e.g. wlan0) gets its address, 'ip route add' without 'dev $interface' sets
the route on the other interface. The result looks like:

  # ip route
  default via 192.168.1.1 dev eth0  metric 5
  default via 192.168.1.1 dev eth0  metric 10          # wrong dev here
  192.168.1.0/24 dev eth0 scope link  src 192.168.1.20
  192.168.1.0/24 dev wlan0 scope link  src 192.168.1.30
  #

The situation might go unnoticed until eth0 is disconnected, because only
wlan0 is present but there is no route through wlan0.

Fix by explicitly passing "dev $interface" to 'ip route add'. Note that all
other 'ip' invocations already have "dev $interface" passed.

(From OE-Core rev: bb526eee429f25b85372f41e4d6d2865bcc39173)

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/meta/recipes-core/busybox/files/simple.script b/meta/recipes-core/busybox/files/simple.script
index 8b5eb53633..013440574d 100644
--- a/meta/recipes-core/busybox/files/simple.script
+++ b/meta/recipes-core/busybox/files/simple.script
@@ -59,7 +59,7 @@ case "$1" in
                         metric=10
                         for i in $router ; do
                                 if [ $have_bin_ip -eq 1 ]; then
-                                        /SBIN_DIR/ip route add default via $i metric $metric
+                                        /SBIN_DIR/ip route add default via $i metric $metric dev $interface
                                 else
                                         /SBIN_DIR/route add default gw $i dev $interface metric $metric 2>/dev/null
                                 fi