- Fill in the correct rtm_index for RTM_ADD and RTM_CHANGE messages.

- Allow RTM_CHANGE to change a number of route flags as specified by
  RTF_FMASK.

- The unused rtm_use field in struct rt_msghdr is redesignated as
  rtm_fmask field to communicate route flag changes in RTM_CHANGE
  messages from userland.  The use count of a route was moved to
  rtm_rmx a long time ago.  For source code compatibility reasons
  a define of rtm_use to rtm_fmask is provided.

These changes faciliate running of multiple cooperating routing
daemons at the same time without causing undesired interference.
Open[BGP|OSPF]D make use of these features to have IGP routes
override EGP ones.

Obtained from:	OpenBSD (claudio@)
MFC after:	3 days

2 files changed, 15 insertions, 1 deletions

diff --git a/sys/net/route.h b/sys/net/route.h
index b7f514c..b408213 100644
--- a/sys/net/route.h
+++ b/sys/net/route.h
@@ -169,6 +169,11 @@ struct ortentry {
 #define	RTF_MULTICAST	0x800000	/* route represents a mcast address */
 					/* 0x1000000 and up unassigned */
 
+/* Mask of RTF flags that are allowed to be modified by RTM_CHANGE. */
+#define RTF_FMASK	\
+	(RTF_PROTO1 | RTF_PROTO2 | RTF_PROTO3 | RTF_BLACKHOLE | \
+	 RTF_REJECT | RTF_STATIC)
+
 /*
  * Routing statistics.
  */
@@ -192,7 +197,8 @@ struct rt_msghdr {
 	pid_t	rtm_pid;	/* identify sender */
 	int	rtm_seq;	/* for sender to identify action */
 	int	rtm_errno;	/* why failed */
-	int	rtm_use;	/* from rtentry */
+	int	rtm_fmask;	/* bitmask used in RTM_CHANGE message */
+#define	rtm_use	rtm_fmask	/* deprecated, use rtm_rmx->rmx_pksent */
 	u_long	rtm_inits;	/* which metrics we are initializing */
 	struct	rt_metrics rtm_rmx; /* metrics themselves */
 };
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index f0a978d..ea3bac2 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -379,6 +379,7 @@ route_output(struct mbuf *m, struct socket *so)
 			RT_LOCK(saved_nrt);
 			rt_setmetrics(rtm->rtm_inits,
 				&rtm->rtm_rmx, &saved_nrt->rt_rmx);
+			rtm->rtm_index = saved_nrt->rt_ifp->if_index;
 			RT_REMREF(saved_nrt);
 			saved_nrt->rt_genmask = info.rti_info[RTAX_GENMASK];
 			RT_UNLOCK(saved_nrt);
@@ -480,6 +481,7 @@ route_output(struct mbuf *m, struct socket *so)
 			}
 			(void)rt_msg2(rtm->rtm_type, &info, (caddr_t)rtm, NULL);
 			rtm->rtm_flags = rt->rt_flags;
+			rtm->rtm_use = 0;
 			rt_getmetrics(&rt->rt_rmx, &rtm->rtm_rmx);
 			rtm->rtm_addrs = info.rti_addrs;
 			break;
@@ -522,8 +524,14 @@ route_output(struct mbuf *m, struct socket *so)
 				        rt->rt_ifp = info.rti_ifp;
 				}
 			}
+			/* Allow some flags to be toggled on change. */
+			if (rtm->rtm_fmask & RTF_FMASK)
+				rt->rt_flags = (rt->rt_flags &
+				    ~rtm->rtm_fmask) |
+				    (rtm->rtm_flags & rtm->rtm_fmask);
 			rt_setmetrics(rtm->rtm_inits, &rtm->rtm_rmx,
 					&rt->rt_rmx);
+			rtm->rtm_index = rt->rt_ifp->if_index;
 			if (rt->rt_ifa && rt->rt_ifa->ifa_rtrequest)
 			       rt->rt_ifa->ifa_rtrequest(RTM_ADD, rt, &info);
 			if (info.rti_info[RTAX_GENMASK])