busybox: udhcpc source IP rebind patch

Patch sets the source IP address of DHCP request messages during rebind to the IP address
assigned to the udhcpc client. Source address 0.0.0.0 can only be used by a client prior
to obtaining its IP address (see RFC2131 § 4.1). Source IP address behavior lines up now with
the ISC dhcp client implementation for DHCP request messages during rebind and DHCP release
messages.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

SVN-Revision: 40878

package/utils/busybox/patches/204-udhcpc_src_ip_rebind.patch

@@ -0,0 +1,53 @@
+Index: busybox-1.22.1/networking/udhcp/dhcpc.c
+===================================================================
+--- busybox-1.22.1.orig/networking/udhcp/dhcpc.c
++++ busybox-1.22.1/networking/udhcp/dhcpc.c
+@@ -659,10 +659,10 @@ static void add_client_options(struct dh
+  * client reverts to using the IP broadcast address.
+  */
+ 
+-static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
++static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
+ {
+ 	return udhcp_send_raw_packet(packet,
+-		/*src*/ INADDR_ANY, CLIENT_PORT,
++		/*src*/ src_nip, CLIENT_PORT,
+ 		/*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
+ 		client_config.ifindex);
+ }
+@@ -673,7 +673,7 @@ static int bcast_or_ucast(struct dhcp_pa
+ 		return udhcp_send_kernel_packet(packet,
+ 			ciaddr, CLIENT_PORT,
+ 			server, SERVER_PORT);
+-	return raw_bcast_from_client_config_ifindex(packet);
++	return raw_bcast_from_client_config_ifindex(packet, ciaddr);
+ }
+ 
+ /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
+@@ -701,7 +701,7 @@ static NOINLINE int send_discover(uint32
+ 
+ 	if (msgs++ < 3)
+ 	bb_info_msg("Sending discover...");
+-	return raw_bcast_from_client_config_ifindex(&packet);
++	return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
+ }
+ 
+ /* Broadcast a DHCP request message */
+@@ -745,7 +745,7 @@ static NOINLINE int send_select(uint32_t
+ 
+ 	addr.s_addr = requested;
+ 	bb_info_msg("Sending select for %s...", inet_ntoa(addr));
+-	return raw_bcast_from_client_config_ifindex(&packet);
++	return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
+ }
+ 
+ /* Unicast or broadcast a DHCP renew message */
+@@ -813,7 +813,7 @@ static NOINLINE int send_decline(/*uint3
+ 	udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
+ 
+ 	bb_info_msg("Sending decline...");
+-	return raw_bcast_from_client_config_ifindex(&packet);
++	return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
+ }
+ #endif
+