busybox options -I IP, --server-filter IP for https://github.com/imincik/gis-lab/issues/333: patch against ubuntu precise package

gistfile1.diff

diff --git a/debian/config/pkg/deb b/debian/config/pkg/deb
index 506256e..d9f989a 100644
--- a/debian/config/pkg/deb
+++ b/debian/config/pkg/deb
@@ -831,6 +831,7 @@ CONFIG_UDHCP_DEBUG=0
 CONFIG_FEATURE_UDHCP_RFC3397=y
 CONFIG_UDHCPC_DEFAULT_SCRIPT="/usr/share/udhcpc/default.script"
 CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS=80
+CONFIG_FEATURE_UDHCPC_FILTER=y
 CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS=""
 # CONFIG_UDPSVD is not set
 # CONFIG_VCONFIG is not set
diff --git a/debian/config/pkg/initramfs b/debian/config/pkg/initramfs
index 37bef92..3875cb1 100644
--- a/debian/config/pkg/initramfs
+++ b/debian/config/pkg/initramfs
@@ -819,6 +819,7 @@ CONFIG_UDHCP_DEBUG=0
 # CONFIG_FEATURE_UDHCP_RFC3397 is not set
 CONFIG_UDHCPC_DEFAULT_SCRIPT=""
 CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS=0
+CONFIG_FEATURE_UDHCPC_FILTER=y
 CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS=""
 # CONFIG_UDPSVD is not set
 # CONFIG_VCONFIG is not set
diff --git a/debian/config/pkg/static b/debian/config/pkg/static
index 76305c0..ddfb921 100644
--- a/debian/config/pkg/static
+++ b/debian/config/pkg/static
@@ -831,6 +831,7 @@ CONFIG_UDHCP_DEBUG=0
 CONFIG_FEATURE_UDHCP_RFC3397=y
 CONFIG_UDHCPC_DEFAULT_SCRIPT="/usr/share/udhcpc/default.script"
 CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS=80
+CONFIG_FEATURE_UDHCPC_FILTER=y
 CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS="-R -n"
 # CONFIG_UDPSVD is not set
 CONFIG_VCONFIG=y
diff --git a/debian/config/pkg/udeb b/debian/config/pkg/udeb
index ce64299..8524aca 100644
--- a/debian/config/pkg/udeb
+++ b/debian/config/pkg/udeb
@@ -823,6 +823,7 @@ CONFIG_UDHCP_DEBUG=0
 CONFIG_FEATURE_UDHCP_RFC3397=y
 CONFIG_UDHCPC_DEFAULT_SCRIPT="/usr/share/udhcpc/default.script"
 CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS=80
+CONFIG_FEATURE_UDHCPC_FILTER=y
 CONFIG_IFUPDOWN_UDHCPC_CMD_OPTIONS=""
 # CONFIG_UDPSVD is not set
 CONFIG_VCONFIG=y
diff --git a/networking/udhcp/Config.src b/networking/udhcp/Config.src
index dcd493f..f2db190 100644
--- a/networking/udhcp/Config.src
+++ b/networking/udhcp/Config.src
@@ -130,3 +130,11 @@ config UDHCPC_SLACK_FOR_BUGGY_SERVERS
 	    maximum size of entire IP packet, and sends packets which are
 	    28 bytes too large.
 	  Seednet (ISP) VDSL: sends packets 2 bytes too large.
+
+config FEATURE_UDHCPC_FILTER
+	bool "Add udhcpc filter option ignoring all but one server"
+	default n
+	depends on UDHCPC
+	help
+	  If selected, udhcpc will have option to ignore all DHCP responses not
+	  comming from the server IP specified on command line.
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 5bc00f4..ca8ff14 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -894,6 +894,9 @@ static void client_background(void)
 //usage:     "\n	-H,-h,--hostname NAME	Send NAME as client hostname (default none)"
 //usage:     "\n	-V,--vendorclass VENDOR	Vendor identifier (default 'udhcp VERSION')"
 //usage:     "\n	-C,--clientid-none	Don't send MAC as client identifier"
+//usage:	IF_FEATURE_UDHCPC_FILTER(
+//usage:     "\n	-I,--server-filter IP	Ignore responses from servers other than given one"
+//usage:	)
 //usage:	IF_UDHCP_VERBOSE(
 //usage:     "\n	-v			Verbose"
 //usage:	)
@@ -931,6 +934,9 @@ static void client_background(void)
 //usage:     "\n	-H,-h NAME	Send NAME as client hostname (default none)"
 //usage:     "\n	-V VENDOR	Vendor identifier (default 'udhcp VERSION')"
 //usage:     "\n	-C		Don't send MAC as client identifier"
+//usage:	IF_FEATURE_UDHCPC_FILTER(
+//usage:     "\n	-I IP	Ignore responses from servers other than given one"
+//usage:	)
 //usage:	IF_UDHCP_VERBOSE(
 //usage:     "\n	-v		Verbose"
 //usage:	)
@@ -942,6 +948,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 	uint8_t *temp, *message;
 	const char *str_V, *str_h, *str_F, *str_r;
 	IF_FEATURE_UDHCP_PORT(char *str_P;)
+	IF_FEATURE_UDHCPC_FILTER(const char *str_I;)
 	void *clientid_mac_ptr;
 	llist_t *list_O = NULL;
 	llist_t *list_x = NULL;
@@ -961,6 +968,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 	struct timeval tv;
 	struct dhcp_packet packet;
 	fd_set rfds;
+	IF_FEATURE_UDHCPC_FILTER(uint32_t server_filter_addr;)
 
 #if ENABLE_LONG_OPTS
 	static const char udhcpc_longopts[] ALIGN1 =
@@ -986,6 +994,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		"background\0"     No_argument       "b"
 		IF_FEATURE_UDHCPC_ARPING("arping\0"	No_argument       "a")
 		IF_FEATURE_UDHCP_PORT("client-port\0"	Required_argument "P")
+		IF_FEATURE_UDHCPC_FILTER("server-filter\0" Required_argument "I")
 		;
 #endif
 	enum {
@@ -1014,9 +1023,11 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		USE_FOR_MMU(             OPTBIT_b,)
 		IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
 		IF_FEATURE_UDHCP_PORT(   OPTBIT_P,)
+		IF_FEATURE_UDHCPC_FILTER(OPTBIT_I,)
 		USE_FOR_MMU(             OPT_b = 1 << OPTBIT_b,)
 		IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
 		IF_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
+		IF_FEATURE_UDHCPC_FILTER(OPT_I = 1 << OPTBIT_I,)
 	};
 
 	/* Default options */
@@ -1038,6 +1049,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		USE_FOR_MMU("b")
 		IF_FEATURE_UDHCPC_ARPING("a")
 		IF_FEATURE_UDHCP_PORT("P:")
+		IF_FEATURE_UDHCPC_FILTER("I:")
 		"v"
 		, &str_V, &str_h, &str_h, &str_F
 		, &client_config.interface, &client_config.pidfile, &str_r /* i,p */
@@ -1046,6 +1058,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		, &list_O
 		, &list_x
 		IF_FEATURE_UDHCP_PORT(, &str_P)
+		IF_FEATURE_UDHCPC_FILTER(, &str_I)
 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 		, &dhcp_verbose
 #endif
@@ -1123,6 +1136,17 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 		logmode |= LOGMODE_SYSLOG;
 	}
 
+#if ENABLE_FEATURE_UDHCPC_FILTER
+	if (opt & OPT_I) {
+		struct in_addr temp_addr;
+		if(inet_aton(str_I, &temp_addr)) {
+			server_filter_addr = temp_addr.s_addr;
+		} else {
+			bb_perror_msg_and_die("server filter address can't be parsed:%s",str_I);
+		}
+	}
+#endif
+
 	/* Make sure fd 0,1,2 are open */
 	bb_sanitize_stdio();
 	/* Equivalent of doing a fflush after every \n */
@@ -1369,6 +1393,12 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 			continue;
 		}
 
+#if ENABLE_FEATURE_UDHCPC_FILTER
+		if (packet.siaddr_nip != server_filter_addr) {
+			log1("siaddr_nip %x does not match our server %x, ignoring packet",packet.siaddr_nip, server_filter_addr);
+			continue;
+		}
+#endif
 		message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
 		if (message == NULL) {
 			bb_error_msg("no message type option, ignoring packet");