From c4cc60979637341ef3c2c9b52d5b7945f7b4fac1 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 23 Apr 2019 12:23:44 +0000
Subject: [PATCH] poib: assign link-local address according to RFC

RFC 4391 specifies that the IB interface GID should be re-used as IPv6
link-local address.  Since the code in in6_get_hw_ifid() ignored
IFT_INFINIBAND case, ibX interfaces ended up with the local address
borrowed from some other interface, which is non-compliant.

Use lowest eight bytes from GID for filling the link-local address,
same as Linux.

Reviewed by:	bz (previous version), ae, hselasky, slavash,
Sponsored by:	Mellanox Technologies
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D20006
---
 sys/netinet6/in6_ifattach.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 4fb81f812dd2..a1a707449bf2 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -328,6 +328,14 @@ in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
 		NET_EPOCH_EXIT(et);
 		return -1;
 
+	case IFT_INFINIBAND:
+		if (addrlen != 20) {
+			NET_EPOCH_EXIT(et);
+			return -1;
+		}
+		bcopy(addr + 12, &in6->s6_addr[8], 8);
+		break;
+
 	default:
 		NET_EPOCH_EXIT(et);
 		return -1;