- Propagate the largest set of interface capabilities supported by all lagg

ports to the lagg interface.
- Use the MTU from the first interface as the lagg MTU, all extra interfaces
  must be the same.

This fixes using a lagg interface for a vlan or enabling jumbo frames, etc.

Approved by:	re (kensmith)
MFC After:	3 days

share/man/man4/lagg.4

@@ -122,6 +122,9 @@ command or using the
 .Va cloned_interfaces
 variable in
 .Xr rc.conf 5 .
+.Pp
+The MTU of the first interface to be added is used as the lagg MTU.
+All additional interfaces are required to have exactly the same value.
 .Sh EXAMPLES
 Create a 802.3ad link aggregation using LACP with two
 .Xr bge 4

sys/net/if_lagg.c

@@ -82,7 +82,7 @@ eventhandler_tag	lagg_detach_cookie = NULL;
 static int	lagg_clone_create(struct if_clone *, int, caddr_t);
 static void	lagg_clone_destroy(struct ifnet *);
 static void	lagg_lladdr(struct lagg_softc *, uint8_t *);
-static int	lagg_capabilities(struct lagg_softc *);
+static void	lagg_capabilities(struct lagg_softc *);
 static void	lagg_port_lladdr(struct lagg_port *, uint8_t *);
 static void	lagg_port_setlladdr(void *, int);
 static int	lagg_port_create(struct lagg_softc *, struct ifnet *);
@@ -305,27 +305,32 @@ lagg_lladdr(struct lagg_softc *sc, uint8_t *lladdr)
 		(*sc->sc_lladdr)(sc);
 }
 
-static int
+static void
 lagg_capabilities(struct lagg_softc *sc)
 {
 	struct lagg_port *lp;
-	int cap = ~0, priv;
+	int cap = ~0, ena = ~0;
 
 	LAGG_WLOCK_ASSERT(sc);
 
-	/* Preserve private capabilities */
-	priv = sc->sc_capabilities & IFCAP_LAGG_MASK;
-
 	/* Get capabilities from the lagg ports */
-	SLIST_FOREACH(lp, &sc->sc_ports, lp_entries)
-		cap &= lp->lp_capabilities;
-
-	if (sc->sc_ifflags & IFF_DEBUG) {
-		printf("%s: capabilities 0x%08x\n",
-		    sc->sc_ifname, cap == ~0 ? priv : (cap | priv));
+	SLIST_FOREACH(lp, &sc->sc_ports, lp_entries) {
+		cap &= lp->lp_ifp->if_capabilities;
+		ena &= lp->lp_ifp->if_capenable;
 	}
+	cap = (cap == ~0 ? 0 : cap);
+	ena = (ena == ~0 ? 0 : ena);
 
-	return (cap == ~0 ? priv : (cap | priv));
+	if (sc->sc_ifp->if_capabilities != cap ||
+	    sc->sc_ifp->if_capenable != ena) {
+		sc->sc_ifp->if_capabilities = cap;
+		sc->sc_ifp->if_capenable = ena;
+		getmicrotime(&sc->sc_ifp->if_lastchange);
+
+		if (sc->sc_ifflags & IFF_DEBUG)
+			if_printf(sc->sc_ifp,
+			    "capabilities 0x%08x enabled 0x%08x\n", cap, ena);
+	}
 }
 
 static void
@@ -426,6 +431,15 @@ lagg_port_create(struct lagg_softc *sc, struct ifnet *ifp)
 	if (ifp->if_type != IFT_ETHER)
 		return (EPROTONOSUPPORT);
 
+	/* Allow the first Ethernet member to define the MTU */
+	if (SLIST_EMPTY(&sc->sc_ports))
+		sc->sc_ifp->if_mtu = ifp->if_mtu;
+	else if (sc->sc_ifp->if_mtu != ifp->if_mtu) {
+		if_printf(sc->sc_ifp, "invalid MTU for %s\n",
+		    ifp->if_xname);
+		return (EINVAL);
+	}
+
 	if ((lp = malloc(sizeof(struct lagg_port),
 	    M_DEVBUF, M_NOWAIT|M_ZERO)) == NULL)
 		return (ENOMEM);
@@ -478,7 +492,7 @@ lagg_port_create(struct lagg_softc *sc, struct ifnet *ifp)
 	sc->sc_count++;
 
 	/* Update lagg capabilities */
-	sc->sc_capabilities = lagg_capabilities(sc);
+	lagg_capabilities(sc);
 
 	/* Add multicast addresses and interface flags to this port */
 	lagg_ether_cmdmulti(lp, 1);
@@ -583,7 +597,7 @@ lagg_port_destroy(struct lagg_port *lp, int runpd)
 	free(lp, M_DEVBUF);
 
 	/* Update lagg capabilities */
-	sc->sc_capabilities = lagg_capabilities(sc);
+	lagg_capabilities(sc);
 
 	return (0);
 }
@@ -619,6 +633,27 @@ lagg_port_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 		lagg_port2req(lp, rp);
 		LAGG_RUNLOCK(sc);
 		break;
+
+	case SIOCSIFCAP:
+		if (lp->lp_ioctl == NULL) {
+			error = EINVAL;
+			break;
+		}
+		error = (*lp->lp_ioctl)(ifp, cmd, data);
+		if (error)
+			break;
+
+		/* Update lagg interface capabilities */
+		LAGG_WLOCK(sc);
+		lagg_capabilities(sc);
+		LAGG_WUNLOCK(sc);
+		break;
+
+	case SIOCSIFMTU:
+		/* Do not allow the MTU to be changed once joined */
+		error = EINVAL;
+		break;
+
 	default:
 		goto fallback;
 	}
@@ -934,6 +969,13 @@ lagg_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
 	case SIOCGIFMEDIA:
 		error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
 		break;
+
+	case SIOCSIFCAP:
+	case SIOCSIFMTU:
+		/* Do not allow the MTU or caps to be directly changed */
+		error = EINVAL;
+		break;
+
 	default:
 		error = ether_ioctl(ifp, cmd, data);
 		break;

sys/net/if_lagg.h

@@ -127,7 +127,6 @@ struct lagg_reqall {
 
 #define	lp_ifname		lp_ifp->if_xname	/* interface name */
 #define	lp_link_state		lp_ifp->if_link_state	/* link state */
-#define	lp_capabilities		lp_ifp->if_capabilities	/* capabilities */
 
 #define	LAGG_PORTACTIVE(_tp)	(					\
 	((_tp)->lp_link_state == LINK_STATE_UP) &&			\