Subject: [PATCH net-next] net: ipv6: Generate random IID for addresses on RAWIP devices

From: Subash Abhinov Kasiviswanathan <[email-masked]>
Date: Sun, 3 Jun 2018 15:54:34 -0600

RAWIP devices such as rmnet do not have a hardware address and
instead require the kernel to generate a random IID for the
temporary addresses. For permanent addresses, the device IID is
used along with prefix received.

Signed-off-by: Subash Abhinov Kasiviswanathan <[email-masked]>
---
 net/ipv6/addrconf.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f09afc2..e4c4540 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2230,6 +2230,18 @@ static int addrconf_ifid_ip6tnl(u8 *eui, struct net_device *dev)
 	return 0;
 }
 
+static int addrconf_ifid_rawip(u8 *eui, struct net_device *dev)
+{
+	struct in6_addr lladdr;
+
+	if (ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE))
+		get_random_bytes(eui, 8);
+	else
+		memcpy(eui, lladdr.s6_addr + 8, 8);
+
+	return 0;
+}
+
 static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
 {
 	switch (dev->type) {
@@ -2252,6 +2264,8 @@ static int ipv6_generate_eui64(u8 *eui, struct net_device *dev)
 	case ARPHRD_TUNNEL6:
 	case ARPHRD_IP6GRE:
 		return addrconf_ifid_ip6tnl(eui, dev);
+	case ARPHRD_RAWIP:
+		return addrconf_ifid_rawip(eui, dev);
 	}
 	return -1;
 }
@@ -3286,7 +3300,8 @@ static void addrconf_dev_config(struct net_device *dev)
 	    (dev->type != ARPHRD_IP6GRE) &&
 	    (dev->type != ARPHRD_IPGRE) &&
 	    (dev->type != ARPHRD_TUNNEL) &&
-	    (dev->type != ARPHRD_NONE)) {
+	    (dev->type != ARPHRD_NONE) &&
+	    (dev->type != ARPHRD_RAWIP)) {
 		/* Alas, we support only Ethernet autoconfiguration. */
 		return;
 	}
-- 
1.9.1