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-rw-r--r--include/net/addrconf.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 0c3ac5acb85f..b5474b1fcd83 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -91,6 +91,37 @@ int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2);
void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr);
void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr);
+static inline int addrconf_ifid_eui48(u8 *eui, struct net_device *dev)
+{
+ if (dev->addr_len != ETH_ALEN)
+ return -1;
+ memcpy(eui, dev->dev_addr, 3);
+ memcpy(eui + 5, dev->dev_addr + 3, 3);
+
+ /*
+ * The zSeries OSA network cards can be shared among various
+ * OS instances, but the OSA cards have only one MAC address.
+ * This leads to duplicate address conflicts in conjunction
+ * with IPv6 if more than one instance uses the same card.
+ *
+ * The driver for these cards can deliver a unique 16-bit
+ * identifier for each instance sharing the same card. It is
+ * placed instead of 0xFFFE in the interface identifier. The
+ * "u" bit of the interface identifier is not inverted in this
+ * case. Hence the resulting interface identifier has local
+ * scope according to RFC2373.
+ */
+ if (dev->dev_id) {
+ eui[3] = (dev->dev_id >> 8) & 0xFF;
+ eui[4] = dev->dev_id & 0xFF;
+ } else {
+ eui[3] = 0xFF;
+ eui[4] = 0xFE;
+ eui[0] ^= 2;
+ }
+ return 0;
+}
+
static inline unsigned long addrconf_timeout_fixup(u32 timeout,
unsigned int unit)
{