udhcpc: shrink code by setting xid more economically
function old new delta
send_decline 90 82 -8
udhcpc_main 2649 2640 -9
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 43d6823..945600c 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -726,7 +726,7 @@
#if ENABLE_FEATURE_UDHCPC_ARPING
/* Broadcast a DHCP decline message */
/* NOINLINE: limit stack usage in caller */
-static NOINLINE int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
+static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
{
struct dhcp_packet packet;
@@ -735,12 +735,14 @@
*/
init_packet(&packet, DHCPDECLINE);
+#if 0
/* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
* but in case the server is buggy and wants DHCPDECLINE's xid
* to match the xid which started entire handshake,
* we use the same xid we used in initial DHCPDISCOVER:
*/
packet.xid = xid;
+#endif
/* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
@@ -1131,7 +1133,7 @@
int discover_retries = 3;
uint32_t server_addr = server_addr; /* for compiler */
uint32_t requested_ip = 0;
- uint32_t xid = 0;
+ uint32_t xid = xid; /* for compiler */
int packet_num;
int timeout; /* must be signed */
unsigned already_waited_sec;
@@ -1520,7 +1522,7 @@
switch (state) {
case INIT_SELECTING:
- /* Must be a DHCPOFFER to one of our xid's */
+ /* Must be a DHCPOFFER */
if (*message == DHCPOFFER) {
/* What exactly is server's IP? There are several values.
* Example DHCP offer captured with tchdump:
@@ -1600,7 +1602,7 @@
) {
bb_info_msg("Offered address is in use "
"(got ARP reply), declining");
- send_decline(xid, server_addr, packet.yiaddr);
+ send_decline(/*xid,*/ server_addr, packet.yiaddr);
if (state != REQUESTING)
udhcp_run_script(NULL, "deconfig");
@@ -1637,6 +1639,8 @@
opt = ((opt & ~OPT_b) | OPT_f);
}
#endif
+ /* make future renew packets use different xid */
+ /* xid = random_xid(); ...but why bother? */
already_waited_sec = 0;
continue; /* back to main loop */
}