Introduce attributes to interface groups.

As a first user, move the global carp(4) demotion counter
into the interface group. Thus we have the possibility
to define which carp interfaces are demoted together.

Put the demotion counter into the reserved field of the carp header.
With this, we can have carp act smarter if multiple errors occur.
It now always takes over other carp peers, that are advertising
with a higher demote count.  As a side effect, we can also have
group failovers without the need of running in preempt mode.
The protocol change does not break compability with older
implementations.

Collaborative work with mcbride@

OK mcbride@, henning@

1 files changed, 54 insertions, 1 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 4b97d064b0c..97b517fa1f9 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.146 2006/03/22 14:37:44 henning Exp $	*/
+/*	$OpenBSD: if.c,v 1.147 2006/06/02 19:53:12 mpf Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -137,6 +137,8 @@ void	if_detached_watchdog(struct ifnet *);
 
 int	if_getgroup(caddr_t, struct ifnet *);
 int	if_getgroupmembers(caddr_t);
+int	if_getgroupattribs(caddr_t);
+int	if_setgroupattribs(caddr_t);
 
 int	if_clone_list(struct if_clonereq *);
 struct if_clone	*if_clone_lookup(const char *, int *);
@@ -1167,6 +1169,12 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 		return (if_clone_list((struct if_clonereq *)data));
 	case SIOCGIFGMEMB:
 		return (if_getgroupmembers(data));
+	case SIOCGIFGATTR:
+		return (if_getgroupattribs(data));
+	case SIOCSIFGATTR:
+		if ((error = suser(p, 0)) != 0)
+			return (error);
+		return (if_setgroupattribs(data));
 	}
 
 	ifp = ifunit(ifr->ifr_name);
@@ -1280,6 +1288,7 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 	case SIOCAIFGROUP:
 		if ((error = suser(p, 0)))
 			return (error);
+		(*ifp->if_ioctl)(ifp, cmd, data); /* XXX error check */
 		ifgr = (struct ifgroupreq *)data;
 		if ((error = if_addgroup(ifp, ifgr->ifgr_group)))
 			return (error);
@@ -1293,6 +1302,7 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 	case SIOCDIFGROUP:
 		if ((error = suser(p, 0)))
 			return (error);
+		(*ifp->if_ioctl)(ifp, cmd, data); /* XXX error check */
 		ifgr = (struct ifgroupreq *)data;
 		if ((error = if_delgroup(ifp, ifgr->ifgr_group)))
 			return (error);
@@ -1590,6 +1600,7 @@ if_addgroup(struct ifnet *ifp, const char *groupname)
 		}
 		strlcpy(ifg->ifg_group, groupname, sizeof(ifg->ifg_group));
 		ifg->ifg_refcnt = 0;
+		ifg->ifg_carp_demoted = 0;
 		TAILQ_INIT(&ifg->ifg_members);
 #if NPF > 0
 		pfi_attach_ifgroup(ifg);
@@ -1732,6 +1743,48 @@ if_getgroupmembers(caddr_t data)
 	return (0);
 }
 
+int
+if_getgroupattribs(caddr_t data)
+{
+	struct ifgroupreq	*ifgr = (struct ifgroupreq *)data;
+	struct ifg_group	*ifg;
+
+	TAILQ_FOREACH(ifg, &ifg_head, ifg_next)
+		if (!strcmp(ifg->ifg_group, ifgr->ifgr_name))
+			break;
+	if (ifg == NULL)
+		return (ENOENT);
+
+	ifgr->ifgr_attrib.ifg_carp_demoted = ifg->ifg_carp_demoted;
+
+	return (0);
+}
+
+int
+if_setgroupattribs(caddr_t data)
+{
+	struct ifgroupreq	*ifgr = (struct ifgroupreq *)data;
+	struct ifg_group	*ifg;
+	int			 demote;
+
+	TAILQ_FOREACH(ifg, &ifg_head, ifg_next)
+		if (!strcmp(ifg->ifg_group, ifgr->ifgr_name))
+			break;
+	if (ifg == NULL)
+		return (ENOENT);
+
+	demote = ifgr->ifgr_attrib.ifg_carp_demoted;
+	if (demote > 1 || demote < -1)
+		return (E2BIG);
+
+	if (demote + ifg->ifg_carp_demoted >= 0)
+		ifg->ifg_carp_demoted += demote;
+	else
+		ifg->ifg_carp_demoted = 0;
+
+	return (0);
+}
+
 void
 if_group_routechange(struct sockaddr *dst, struct sockaddr *mask)
 {