net: bootp: add config option BOOTP_RANDOM_XID
The new config option BOOTP_RANDOM_XID will randomize the transaction ID
for each new BOOT/DHCPv4 exchange.
Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/net/bootp.c b/net/bootp.c
index c34ffe2..285fcba 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -834,22 +834,25 @@
/* Only generate a new transaction ID for each new BOOTP request */
if (bootp_try == 1) {
- /*
- * Bootp ID is the lower 4 bytes of our ethernet address
- * plus the current time in ms.
- */
- bootp_id = ((u32)net_ethaddr[2] << 24)
- | ((u32)net_ethaddr[3] << 16)
- | ((u32)net_ethaddr[4] << 8)
- | (u32)net_ethaddr[5];
- bootp_id += get_timer(0);
- bootp_id = htonl(bootp_id);
- bootp_add_id(bootp_id);
- net_copy_u32(&bp->bp_id, &bootp_id);
- } else {
- net_copy_u32(&bp->bp_id, &bootp_id);
+ if (IS_ENABLED(CONFIG_BOOTP_RANDOM_XID)) {
+ srand(get_ticks() + rand());
+ bootp_id = rand();
+ } else {
+ /*
+ * Bootp ID is the lower 4 bytes of our ethernet address
+ * plus the current time in ms.
+ */
+ bootp_id = ((u32)net_ethaddr[2] << 24)
+ | ((u32)net_ethaddr[3] << 16)
+ | ((u32)net_ethaddr[4] << 8)
+ | (u32)net_ethaddr[5];
+ bootp_id += get_timer(0);
+ bootp_id = htonl(bootp_id);
+ }
}
+ bootp_add_id(bootp_id);
+ net_copy_u32(&bp->bp_id, &bootp_id);
/*
* Calculate proper packet lengths taking into account the
* variable size of the options field