[IPV6] ADDRCONF: Allow longer lifetime on 64bit archs.
- Allow longer lifetimes (>= 0x7fffffff/HZ) on 64bit archs
by using unsigned long.
- Shadow this arithmetic overflow workaround by introducing
helper functions: addrconf_timeout_fixup() and
addrconf_finite_timeout().
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 0a2f037..bbd3d58 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -94,6 +94,28 @@
extern void addrconf_leave_solict(struct inet6_dev *idev,
struct in6_addr *addr);
+static inline unsigned long addrconf_timeout_fixup(u32 timeout,
+ unsigned unit)
+{
+ if (timeout == 0xffffffff)
+ return ~0UL;
+
+ /*
+ * Avoid arithmetic overflow.
+ * Assuming unit is constant and non-zero, this "if" statement
+ * will go away on 64bit archs.
+ */
+ if (0xfffffffe > LONG_MAX / unit && timeout > LONG_MAX / unit)
+ return LONG_MAX / unit;
+
+ return timeout;
+}
+
+static inline int addrconf_finite_timeout(unsigned long timeout)
+{
+ return ~timeout;
+}
+
/*
* IPv6 Address Label subsystem (addrlabel.c)
*/