From d62081b6dd05a67ee176092f85ee96e83eb74a19 Mon Sep 17 00:00:00 2001
From: claudio <claudio@openbsd.org>
Date: Sat, 10 Feb 2018 05:32:21 +0000
Subject: [PATCH] Similar to the IPv6 case create 127.0.0.1/8 on lo(4)
 interfaces which act as loopback interfaces for each rdomain (including lo0).
 This is done when the interface is brought up. This is now also done by
 default (either on attach of lo0 or when creating the rdomain). OK mpi@

---
 sys/net/if.c      |  7 ++++--
 sys/net/if_loop.c | 15 +++++++++++-
 sys/netinet/in.c  | 58 ++++++++++++++++++++++++++++++++++++++++++++++-
 sys/netinet/in.h  |  3 ++-
 4 files changed, 78 insertions(+), 5 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index 1557cae6cca..e450decf5ed 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.541 2018/02/09 09:35:03 dlg Exp $	*/
+/*	$OpenBSD: if.c,v 1.542 2018/02/10 05:32:21 claudio Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -1550,8 +1550,10 @@ if_up(struct ifnet *ifp)
 
 #ifdef INET6
 	/* Userland expects the kernel to set ::1 on default lo(4). */
-	if (ifp->if_index == rtable_loindex(ifp->if_rdomain))
+	if (ifp->if_index == rtable_loindex(ifp->if_rdomain)) {
 		in6_ifattach(ifp);
+		in_up_loopback(ifp);
+	}
 #endif
 
 	if_linkstate(ifp);
@@ -1744,6 +1746,7 @@ if_setrdomain(struct ifnet *ifp, int rdomain)
 		}
 
 		loifp->if_rdomain = rdomain;
+		if_up(loifp);
 	}
 
 	/* make sure that the routing table is a real rdomain */
diff --git a/sys/net/if_loop.c b/sys/net/if_loop.c
index 5ff594ef091..9cc46c6b700 100644
--- a/sys/net/if_loop.c
+++ b/sys/net/if_loop.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_loop.c,v 1.85 2018/01/09 15:24:24 bluhm Exp $	*/
+/*	$OpenBSD: if_loop.c,v 1.86 2018/02/10 05:32:21 claudio Exp $	*/
 /*	$NetBSD: if_loop.c,v 1.15 1996/05/07 02:40:33 thorpej Exp $	*/
 
 /*
@@ -142,6 +142,7 @@
 
 int	loioctl(struct ifnet *, u_long, caddr_t);
 void	loopattach(int);
+void	loop_delayed_create(void *);
 void	lortrequest(struct ifnet *, int, struct rtentry *);
 int	loinput(struct ifnet *, struct mbuf *, void *);
 int	looutput(struct ifnet *,
@@ -162,9 +163,19 @@ loopattach(int n)
 	if_clone_attach(&loop_cloner);
 }
 
+void
+loop_delayed_create(void *arg)
+{
+	struct ifnet *ifp = arg;
+	NET_LOCK();
+	if_up(ifp);
+	NET_UNLOCK();
+}
+
 int
 loop_clone_create(struct if_clone *ifc, int unit)
 {
+	static struct task lot;
 	struct ifnet *ifp;
 
 	ifp = malloc(sizeof(*ifp), M_DEVBUF, M_WAITOK|M_ZERO);
@@ -182,6 +193,8 @@ loop_clone_create(struct if_clone *ifc, int unit)
 		if_attachhead(ifp);
 		if_addgroup(ifp, ifc->ifc_name);
 		rtable_l2set(0, 0, ifp->if_index);
+		task_set(&lot, loop_delayed_create, ifp);
+		task_add(systq, &lot);
 	} else
 		if_attach(ifp);
 	if_alloc_sadl(ifp);
diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index 5681667a688..3651c120af8 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in.c,v 1.144 2017/11/04 13:11:54 mpi Exp $	*/
+/*	$OpenBSD: in.c,v 1.145 2018/02/10 05:32:21 claudio Exp $	*/
 /*	$NetBSD: in.c,v 1.26 1996/02/13 23:41:39 christos Exp $	*/
 
 /*
@@ -609,6 +609,62 @@ in_broadcast(struct in_addr in, u_int rtableid)
 #undef ia
 }
 
+int
+in_up_loopback(struct ifnet *ifp)
+{
+	struct in_ifaddr *ia;
+	struct rt_addrinfo info;
+	int error;
+
+	if ((ifp->if_flags & IFF_LOOPBACK) == 0)
+		return (0);
+
+	/* configure 127.0.0.1 on the loopback interface */
+	ia = malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
+	ia->ia_addr.sin_family = AF_INET;
+	ia->ia_addr.sin_len = sizeof(ia->ia_addr);
+	ia->ia_addr.sin_addr.s_addr = INADDR_LOOPBACK;
+	ia->ia_ifa.ifa_addr = sintosa(&ia->ia_addr);
+	ia->ia_ifa.ifa_dstaddr = sintosa(&ia->ia_dstaddr);
+	ia->ia_ifa.ifa_netmask = sintosa(&ia->ia_sockmask);
+	ia->ia_netmask = IN_CLASSA_NET;
+	ia->ia_sockmask.sin_len = 8;
+	ia->ia_sockmask.sin_addr.s_addr = ia->ia_netmask;
+	ia->ia_ifp = ifp;
+
+	if (ifaof_ifpforaddr(ia->ia_ifa.ifa_addr, ifp) != NULL) {
+		free(ia, M_IFADDR, sizeof *ia);
+		return (0);
+	}
+
+	/*
+	 * Add the address to the local list and the global tree.  If an
+	 * error occured, cleanup.
+	 */
+	ifa_add(ifp, &ia->ia_ifa);
+	error = rt_ifa_addlocal(&ia->ia_ifa);
+	if (error)
+		goto out;
+
+	ia->ia_net = ia->ia_addr.sin_addr.s_addr & ia->ia_netmask;
+	in_socktrim(&ia->ia_sockmask);
+
+	/* Now insert a reject route for 127.0.0.0/8 */
+	bzero((caddr_t)&info, sizeof(info));
+	info.rti_flags = RTF_GATEWAY | RTF_REJECT | RTF_STATIC;
+	info.rti_ifa = &ia->ia_ifa;
+	info.rti_info[RTAX_DST] = ia->ia_ifa.ifa_addr;
+	info.rti_info[RTAX_NETMASK] = ia->ia_ifa.ifa_netmask;
+	info.rti_info[RTAX_GATEWAY] = ia->ia_ifa.ifa_addr;
+
+	error = rtrequest(RTM_ADD, &info, 0, NULL, ifp->if_rdomain);
+
+out:
+	if (error)
+		in_purgeaddr(&ia->ia_ifa);
+	return (error);
+}
+
 /*
  * Add an address to the list of IP multicast addresses for a given interface.
  */
diff --git a/sys/netinet/in.h b/sys/netinet/in.h
index fc8a7b61044..02233bb3d08 100644
--- a/sys/netinet/in.h
+++ b/sys/netinet/in.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in.h,v 1.127 2017/11/20 10:35:24 mpi Exp $	*/
+/*	$OpenBSD: in.h,v 1.128 2018/02/10 05:32:21 claudio Exp $	*/
 /*	$NetBSD: in.h,v 1.20 1996/02/13 23:41:47 christos Exp $	*/
 
 /*
@@ -811,6 +811,7 @@ int	   in_cksum(struct mbuf *, int);
 int	   in4_cksum(struct mbuf *, u_int8_t, int, int);
 void	   in_proto_cksum_out(struct mbuf *, struct ifnet *);
 void	   in_ifdetach(struct ifnet *);
+int	   in_up_loopback(struct ifnet *);
 int	   in_mask2len(struct in_addr *);
 void	   in_len2mask(struct in_addr *, int);
 int	   in_nam2sin(const struct mbuf *, struct sockaddr_in **);
-- 
2.20.1