vrrpd: allow user to set priority = 255

Too many problems with implicit ownership determination via duplicate
address assignment. Will revisit that in the future. For now, allow user
to specify 255 as a priority value. This is functionally no different
than any other priority value; it just serves as a self-documenting way
of saying you want one router to always be master.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

diff --git a/vrrpd/vrrp.c b/vrrpd/vrrp.c
index fbc738e30866ea1d416323725f24fd68c6d6bdb0..fc0a57b71c1a1b647e91292ddafcfe004bdbeaaf 100644 (file)
--- a/vrrpd/vrrp.c
+++ b/vrrpd/vrrp.c
@@ -107,12 +107,16 @@ static void vrrp_recalculate_timers(struct vrrp_router *r)
  * Determines if a VRRP router is the owner of the specified address.
  *
  * The determining factor for whether an interface is the address owner is
- * simply whether the address is assigned to the VRRP subinterface by someone
+ * simply whether the address is assigned to the VRRP base interface by someone
  * other than vrrpd.
  *
  * This function should always return the correct answer regardless of
  * master/backup status.
  *
+ * ifp
+ *    The interface to check owernship of. This should be the base interface of
+ *    a VRRP router.
+ *
  * vr
  *    Virtual Router
  *
@@ -121,6 +125,23 @@ static void vrrp_recalculate_timers(struct vrrp_router *r)
  */
 static bool vrrp_is_owner(struct interface *ifp, struct ipaddr *addr)
 {
+       /*
+        * This code sanity checks implicit ownership configuration. Ideally,
+        * the way we determine address ownership status for this VRRP router
+        * is by looking at whether our VIPs are also assigned to the base
+        * interface, and therefore count as "real" addresses. This frees the
+        * user from having to manually configure priority 255 to indicate
+        * address ownership. However, this means one of the VIPs will be used
+        * as the source address for VRRP advertisements, which in turn means
+        * that other VRRP routers will be receiving packets with a source
+        * address they themselves have. This causes lots of different issues
+        * so for now we're disabling this and forcing the user to configure
+        * priority 255 to indicate ownership.
+        */
+
+       return false;
+
+#if 0
        struct prefix p;
 
        p.family = IS_IPADDR_V4(addr) ? AF_INET : AF_INET6;
@@ -128,6 +149,7 @@ static bool vrrp_is_owner(struct interface *ifp, struct ipaddr *addr)
        memcpy(&p.u, &addr->ip, sizeof(addr->ip));
 
        return !!connected_lookup_prefix_exact(ifp, &p);
+#endif
 }
 
 /*
@@ -1411,13 +1433,14 @@ static int vrrp_startup(struct vrrp_router *r)
        char ipbuf[INET6_ADDRSTRLEN];
        inet_ntop(r->family, &primary->ip.addr, ipbuf, sizeof(ipbuf));
 
-       if (vrrp_is_owner(r->vr->ifp, primary)) {
+       if (r->vr->priority == VRRP_PRIO_MASTER
+           || vrrp_is_owner(r->vr->ifp, primary)) {
                r->priority = VRRP_PRIO_MASTER;
                vrrp_recalculate_timers(r);
 
                zlog_info(
                        VRRP_LOGPFX VRRP_LOGPFX_VRID
-                       "%s owns primary Virtual Router IP %s; electing self as Master",
+                       "%s has priority set to 255 or owns primary Virtual Router IP %s; electing self as Master",
                        r->vr->vrid, r->vr->ifp->name, ipbuf);
        }
 

diff --git a/vrrpd/vrrp_vty.c b/vrrpd/vrrp_vty.c
index 0498d3c2607007ae405b7c19bb941878b3afaa6c..ec3a70dadb23ada75eea7ad4d7a89664b26e6f0b 100644 (file)
--- a/vrrpd/vrrp_vty.c
+++ b/vrrpd/vrrp_vty.c
@@ -116,7 +116,7 @@ DEFPY(vrrp_shutdown,
 
 DEFPY(vrrp_priority,
       vrrp_priority_cmd,
-      "[no] vrrp (1-255)$vrid priority (1-254)",
+      "[no] vrrp (1-255)$vrid priority (1-255)",
       NO_STR
       VRRP_STR
       VRRP_VRID_STR