Use in6_get_rand_ifid() instead of get_last_resort_ifid() and delete the

get_last_resort_ifid() function because eww.
Also if your system is so constraint that you end up in
in6_get_rand_ifid() you don't deserve a random ifid that stays
stable over reboots.
Simplify code a bit since get_ifid() can no longer fail. It couldn't
fail before either because that code path was #if 0'ed.
While here sprinkle in some in6_ prefixes, pointed out by stsp.
OK stsp

1 files changed, 16 insertions, 67 deletions

diff --git a/sys/netinet6/in6_ifattach.c b/sys/netinet6/in6_ifattach.c
index 89acde9c6a4..87614373686 100644
--- a/sys/netinet6/in6_ifattach.c
+++ b/sys/netinet6/in6_ifattach.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6_ifattach.c,v 1.103 2017/07/11 12:51:05 florian Exp $	*/
+/*	$OpenBSD: in6_ifattach.c,v 1.104 2017/09/01 16:48:27 florian Exp $	*/
 /*	$KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei Exp $	*/
 
 /*
@@ -56,10 +56,10 @@
 #include <netinet6/ip6_mroute.h>
 #endif
 
-int get_last_resort_ifid(struct ifnet *, struct in6_addr *);
-int get_hw_ifid(struct ifnet *, struct in6_addr *);
-int get_ifid(struct ifnet *, struct in6_addr *);
-int in6_ifattach_loopback(struct ifnet *);
+void	in6_get_rand_ifid(struct ifnet *, struct in6_addr *);
+int	in6_get_hw_ifid(struct ifnet *, struct in6_addr *);
+void	in6_get_ifid(struct ifnet *, struct in6_addr *);
+int	in6_ifattach_loopback(struct ifnet *);
 
 #define EUI64_GBIT	0x01
 #define EUI64_UBIT	0x02
@@ -73,45 +73,6 @@ int in6_ifattach_loopback(struct ifnet *);
 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
 
 /*
- * Generate a last-resort interface identifier, when the machine has no
- * IEEE802/EUI64 address sources.
- * The goal here is to get an interface identifier that is
- * (1) random enough and (2) does not change across reboot.
- * We currently use SHA512(hostname) for it.
- *
- * in6 - upper 64bits are preserved
- */
-int
-get_last_resort_ifid(struct ifnet *ifp, struct in6_addr *in6)
-{
-	SHA2_CTX ctx;
-	u_int8_t digest[SHA512_DIGEST_LENGTH];
-
-#if 0
-	/* we need at least several letters as seed for ifid */
-	if (hostnamelen < 3)
-		return -1;
-#endif
-
-	/* generate 8 bytes of pseudo-random value. */
-	SHA512Init(&ctx);
-	SHA512Update(&ctx, hostname, hostnamelen);
-	SHA512Final(digest, &ctx);
-
-	/* assumes sizeof(digest) > sizeof(ifid) */
-	bcopy(digest, &in6->s6_addr[8], 8);
-
-	/* make sure to set "u" bit to local, and "g" bit to individual. */
-	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
-	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
-
-	/* convert EUI64 into IPv6 interface identifier */
-	EUI64_TO_IFID(in6);
-
-	return 0;
-}
-
-/*
  * Generate a random interface identifier.
  *
  * in6 - upper 64bits are preserved
@@ -135,7 +96,7 @@ in6_get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
  * in6 - upper 64bits are preserved
  */
 int
-get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
+in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
 {
 	struct sockaddr_dl *sdl;
 	char *addr;
@@ -235,13 +196,13 @@ get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
  * available on ifp0, borrow interface identifier from other information
  * sources.
  */
-int
-get_ifid(struct ifnet *ifp0, struct in6_addr *in6)
+void
+in6_get_ifid(struct ifnet *ifp0, struct in6_addr *in6)
 {
 	struct ifnet *ifp;
 
 	/* first, try to get it from the interface itself */
-	if (get_hw_ifid(ifp0, in6) == 0) {
+	if (in6_get_hw_ifid(ifp0, in6) == 0) {
 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
 		    ifp0->if_xname));
 		goto success;
@@ -251,7 +212,7 @@ get_ifid(struct ifnet *ifp0, struct in6_addr *in6)
 	TAILQ_FOREACH(ifp, &ifnet, if_list) {
 		if (ifp == ifp0)
 			continue;
-		if (get_hw_ifid(ifp, in6) != 0)
+		if (in6_get_hw_ifid(ifp, in6) != 0)
 			continue;
 
 		/*
@@ -267,22 +228,15 @@ get_ifid(struct ifnet *ifp0, struct in6_addr *in6)
 	}
 
 	/* last resort: get from random number source */
-	if (get_last_resort_ifid(ifp, in6) == 0) {
-		nd6log((LOG_DEBUG,
-		    "%s: interface identifier generated by random number\n",
-		    ifp0->if_xname));
-		goto success;
-	}
-
-	printf("%s: failed to get interface identifier\n", ifp0->if_xname);
-	return -1;
-
+	in6_get_rand_ifid(ifp, in6);
+	nd6log((LOG_DEBUG,
+	    "%s: interface identifier generated by random number\n",
+	    ifp0->if_xname));
 success:
 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
 	    ifp0->if_xname, in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
 	    in6->s6_addr[14], in6->s6_addr[15]));
-	return 0;
 }
 
 /*
@@ -318,13 +272,8 @@ in6_ifattach_linklocal(struct ifnet *ifp, struct in6_addr *ifid)
 		ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
 		ifra.ifra_addr.sin6_addr.s6_addr[8] &= ~EUI64_GBIT;
 		ifra.ifra_addr.sin6_addr.s6_addr[8] |= EUI64_UBIT;
-	} else {
-		if (get_ifid(ifp, &ifra.ifra_addr.sin6_addr) != 0) {
-			nd6log((LOG_ERR,
-			    "%s: no ifid available\n", ifp->if_xname));
-			return (-1);
-		}
-	}
+	} else
+		in6_get_ifid(ifp, &ifra.ifra_addr.sin6_addr);
 
 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
 	ifra.ifra_prefixmask.sin6_family = AF_INET6;