udhcp: add PXELINUX config file option (code 209) definition

[oweals/busybox.git] / networking / udhcp / arpping.c

diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
index 548796e2b8b10ecb706163c5eb90688c8c21e14f..b43e52e964e0b48c3031b41e9c820b9da2d21969 100644 (file)
--- a/networking/udhcp/arpping.c
+++ b/networking/udhcp/arpping.c
@@ -1,11 +1,9 @@
 /* vi: set sw=4 ts=4: */
 /*
- * arpping.c
- *
  * Mostly stolen from: dhcpcd - DHCP client daemon
  * by Yoichi Hariguchi <yoichi@fore.com>
  *
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
 #include <netinet/if_ether.h>
 #include <net/if_arp.h>
@@ -87,6 +85,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
        /* wait for arp reply, and check it */
        timeout_ms = 2000;
        do {
+               typedef uint32_t aliased_uint32_t FIX_ALIASING;
                int r;
                unsigned prevTime = monotonic_ms();
 
@@ -107,7 +106,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
                         && arp.operation == htons(ARPOP_REPLY)
                         /* don't check it: Linux doesn't return proper tHaddr (fixed in 2.6.24?) */
                         /* && memcmp(arp.tHaddr, from_mac, 6) == 0 */
-                        && *((uint32_t *) arp.sInaddr) == test_nip
+                        && *(aliased_uint32_t*)arp.sInaddr == test_nip
                        ) {
                                /* if ARP source MAC matches safe_mac
                                 * (which is client's MAC), then it's not a conflict
@@ -119,8 +118,13 @@ int FAST_FUNC arpping(uint32_t test_nip,
                                break;
                        }
                }
-               timeout_ms -= (unsigned)monotonic_ms() - prevTime;
-       } while (timeout_ms > 0);
+               timeout_ms -= (unsigned)monotonic_ms() - prevTime + 1;
+
+               /* We used to check "timeout_ms > 0", but
+                * this is more under/overflow-resistant
+                * (people did see overflows here when system time jumps):
+                */
+       } while ((unsigned)timeout_ms <= 2000);
 
  ret:
        close(s);