ifupdown.c: allow options to udhcpc to be configurable from .config

This allows more control over options that are passed to udhcpc
that are not configurable via /etc/network/interfaces.

Example: rather than quit when an initial lease isn't found,
you could use "--background" so that udhcpc keeps running and
continually attempts to get an ip.  That way, when you plug in
the ethernet after powering on the device, you'll still get an ip.

2 files changed, 13 insertions, 2 deletions

diff --git a/networking/Config.in b/networking/Config.in
index 95f894230..735415ccb 100644
--- a/networking/Config.in
+++ b/networking/Config.in
@@ -858,6 +858,15 @@ config FEATURE_TRACEROUTE_USE_ICMP
 
 source networking/udhcp/Config.in
 
+config IFUPDOWN_UDHCPC_CMD_OPTIONS
+        string "ifup udhcpc command line options"
+        default "-R -n"
+        depends on IFUPDOWN && APP_UDHCPC
+        help
+          Command line options to pass to udhcpc from ifup.
+          Intended to alter options not available in /etc/network/interfaces.
+          (IE: --syslog --background etc...)
+
 config VCONFIG
         bool "vconfig"
         default n
diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index d7cb40f32..07855f07f 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -31,6 +31,8 @@
 #define MAX_INTERFACE_LENGTH 10
 #endif
 
+#define UDHCPC_CMD_OPTIONS CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS
+
 #define debug_noise(args...) /*fprintf(stderr, args)*/
 
 /* Forward declaration */
@@ -487,7 +489,7 @@ static const struct dhcp_client_t ext_dhcp_clients[] = {
                 "pump -i %iface% -k",
         },
         { "udhcpc",
-                "udhcpc -R -n -p /var/run/udhcpc.%iface%.pid -i %iface%[[ -H %hostname%]][[ -c %clientid%]]"
+                "udhcpc " UDHCPC_CMD_OPTIONS " -p /var/run/udhcpc.%iface%.pid -i %iface%[[ -H %hostname%]][[ -c %clientid%]]"
                                 "[[ -s %script%]][[ %udhcpc_opts%]]",
                 "kill `cat /var/run/udhcpc.%iface%.pid` 2>/dev/null",
         },
@@ -526,7 +528,7 @@ static int dhcp_up(struct interface_defn_t *ifd, execfn *exec)
         if (!execute("ifconfig %iface%[[ hw %hwaddress%]] up", ifd, exec))
                 return 0;
 #endif
-        return execute("udhcpc -R -n -p /var/run/udhcpc.%iface%.pid "
+        return execute("udhcpc " UDHCPC_CMD_OPTIONS " -p /var/run/udhcpc.%iface%.pid "
                         "-i %iface%[[ -H %hostname%]][[ -c %clientid%]][[ -s %script%]][[ %udhcpc_opts%]]",
                         ifd, exec);
 }