From 5c34a7158dd01da524fff4cea5a006b3ced065d2 Mon Sep 17 00:00:00 2001
From: ozaki-r <ozaki-r@NetBSD.org>
Date: Fri, 15 Aug 2014 15:03:03 +0000
Subject: [PATCH] Make shmif SIMPLEX

Add a sender field to a packet header on a shmif bus to identify
and ignore packets sent by itself.

This makes shmif work with bridges.

ok pooka@
---
 sys/rump/net/lib/libshmif/if_shmem.c | 14 ++++++++++----
 sys/rump/net/lib/libshmif/shmifvar.h |  4 +++-
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/sys/rump/net/lib/libshmif/if_shmem.c b/sys/rump/net/lib/libshmif/if_shmem.c
index 50ab14c5e7b2..89b8b91a82c2 100644
--- a/sys/rump/net/lib/libshmif/if_shmem.c
+++ b/sys/rump/net/lib/libshmif/if_shmem.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: if_shmem.c,v 1.62 2014/08/09 09:43:49 ozaki-r Exp $	*/
+/*	$NetBSD: if_shmem.c,v 1.63 2014/08/15 15:03:03 ozaki-r Exp $	*/
 
 /*
  * Copyright (c) 2009, 2010 Antti Kantee.  All Rights Reserved.
@@ -28,7 +28,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.62 2014/08/09 09:43:49 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.63 2014/08/15 15:03:03 ozaki-r Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -97,6 +97,8 @@ struct shmif_sc {
 
 	struct lwp *sc_rcvl;
 	bool sc_dying;
+
+	uint64_t sc_uuid;
 };
 
 static void shmif_rcv(void *);
@@ -167,12 +169,13 @@ allocif(int unit, struct shmif_sc **scp)
 	sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);
 	sc->sc_memfd = -1;
 	sc->sc_unit = unit;
+	sc->sc_uuid = cprng_fast64();
 
 	ifp = &sc->sc_ec.ec_if;
 
 	snprintf(ifp->if_xname, sizeof(ifp->if_xname), "shmif%d", unit);
 	ifp->if_softc = sc;
-	ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST;
+	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
 	ifp->if_init = shmif_init;
 	ifp->if_ioctl = shmif_ioctl;
 	ifp->if_start = shmif_start;
@@ -540,6 +543,7 @@ shmif_start(struct ifnet *ifp)
 		sp.sp_len = pktsize;
 		sp.sp_sec = tv.tv_sec;
 		sp.sp_usec = tv.tv_usec;
+		sp.sp_sender = sc->sc_uuid;
 
 		bpf_mtap(ifp, m0);
 
@@ -743,7 +747,9 @@ shmif_rcv(void *arg)
 		 * Test if we want to pass the packet upwards
 		 */
 		eth = mtod(m, struct ether_header *);
-		if (memcmp(eth->ether_dhost, CLLADDR(ifp->if_sadl),
+		if (sp.sp_sender == sc->sc_uuid) {
+			passup = false;
+		} else if (memcmp(eth->ether_dhost, CLLADDR(ifp->if_sadl),
 		    ETHER_ADDR_LEN) == 0) {
 			passup = true;
 		} else if (ETHER_IS_MULTICAST(eth->ether_dhost)) {
diff --git a/sys/rump/net/lib/libshmif/shmifvar.h b/sys/rump/net/lib/libshmif/shmifvar.h
index 7e9e509dc887..cb913c576b85 100644
--- a/sys/rump/net/lib/libshmif/shmifvar.h
+++ b/sys/rump/net/lib/libshmif/shmifvar.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: shmifvar.h,v 1.7 2013/12/20 09:06:35 pooka Exp $	*/
+/*	$NetBSD: shmifvar.h,v 1.8 2014/08/15 15:03:03 ozaki-r Exp $	*/
 
 /*-
  * Copyright (c) 2009, 2010 Antti Kantee.  All Rights Reserved.
@@ -56,6 +56,8 @@ struct shmif_pkthdr {
 
 	uint32_t sp_sec;
 	uint32_t sp_usec;
+
+	uint64_t sp_sender;
 };
 
 #define BUSMEM_SIZE (1024*1024)