Introduce an interface announcement message for the routing

socket so that routing daemons and other interested parties
know when an interface is attached/detached.

PR:		kern/33747
Obtained from:	NetBSD
MFC after:	2 weeks

4 files changed, 55 insertions, 0 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 7ffb296..8310190 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -430,6 +430,9 @@ if_attach(ifp)
 		TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
 	}
 	ifp->if_broadcastaddr = 0; /* reliably crash if used uninitialized */
+
+	/* Announce the interface. */
+	rt_ifannouncemsg(ifp, IFAN_ARRIVAL);
 }
 
 /*
@@ -511,6 +514,9 @@ if_detach(ifp)
 		(void) rnh->rnh_walktree(rnh, if_rtdel, ifp);
 	}
 
+	/* Announce that the interface is gone. */
+	rt_ifannouncemsg(ifp, IFAN_DEPARTURE);
+
 	KNOTE(&ifp->if_klist, NOTE_EXIT);
 	TAILQ_REMOVE(&ifnet, ifp, if_link);
 	mtx_destroy(&ifp->if_snd.ifq_mtx);
diff --git a/sys/net/if.h b/sys/net/if.h
index 6cc5522..7370e12 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -197,6 +197,21 @@ struct ifma_msghdr {
 };
 
 /*
+ * Message format announcing the arrival or departure of a network interface.
+ */
+struct if_announcemsghdr {
+	u_short	ifan_msglen;	/* to skip over non-understood messages */
+	u_char	ifan_version;	/* future binary compatibility */
+	u_char	ifan_type;	/* message type */
+	u_short	ifan_index;	/* index for associated ifp */
+	char	ifan_name[IFNAMSIZ]; /* if name, e.g. "en0" */
+	u_short	ifan_what;	/* what type of announcement */
+};
+
+#define	IFAN_ARRIVAL	0	/* interface arrival */
+#define	IFAN_DEPARTURE	1	/* interface departure */
+
+/*
  * Interface request structure used for socket
  * ioctl's.  All interface ioctl's must have parameter
  * definitions which begin with ifr_name.  The
diff --git a/sys/net/route.h b/sys/net/route.h
index d4de208..838915b 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -207,6 +207,7 @@ struct rt_msghdr {
 #define RTM_IFINFO	0xe	/* iface going up/down etc. */
 #define	RTM_NEWMADDR	0xf	/* mcast group membership being added to if */
 #define	RTM_DELMADDR	0x10	/* mcast group membership being deleted */
+#define	RTM_IFANNOUNCE	0x11	/* iface arrival/departure */
 
 /*
  * Bitmask values for rtm_inits and rmx_locks.
@@ -277,6 +278,7 @@ struct ifmultiaddr;
 
 void	 route_init __P((void));
 int	 rt_getifa __P((struct rt_addrinfo *));
+void	 rt_ifannouncemsg __P((struct ifnet *, int));
 void	 rt_ifmsg __P((struct ifnet *));
 void	 rt_missmsg __P((int, struct rt_addrinfo *, int, int));
 void	 rt_newaddrmsg __P((int, struct ifaddr *, int, struct rtentry *));
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index c55d765..88c9cc6 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -595,6 +595,10 @@ rt_msg1(type, rtinfo)
 		len = sizeof(struct if_msghdr);
 		break;
 
+	case RTM_IFANNOUNCE:
+		len = sizeof(struct if_announcemsghdr);
+		break;
+
 	default:
 		len = sizeof(struct rt_msghdr);
 	}
@@ -861,6 +865,34 @@ rt_newmaddrmsg(cmd, ifma)
 }
 
 /*
+ * This is called to generate routing socket messages indicating
+ * network interface arrival and departure.
+ */
+void
+rt_ifannouncemsg(ifp, what)
+	struct ifnet *ifp;
+	int what;
+{
+	struct if_announcemsghdr *ifan;
+	struct mbuf *m;
+	struct rt_addrinfo info;
+
+	if (route_cb.any_count == 0)
+		return;
+	bzero((caddr_t)&info, sizeof(info));
+	m = rt_msg1(RTM_IFANNOUNCE, &info);
+	if (m == NULL)
+		return;
+	ifan = mtod(m, struct if_announcemsghdr *);
+	ifan->ifan_index = ifp->if_index;
+	snprintf(ifan->ifan_name, sizeof(ifan->ifan_name),
+	    "%s%d", ifp->if_name, ifp->if_unit);
+	ifan->ifan_what = what;
+	route_proto.sp_protocol = 0;
+	raw_input(m, &route_proto, &route_src, &route_dst);
+ }
+
+/*
  * This is used in dumping the kernel table via sysctl().
  */
 int