Simplify up_generate_updates()

Instead of using new == NULL or new != NULL in combination with an again
label to steer the control flow of this function, switch to using a while
loop and break/continue/return. Simplified version of a diff by claudio.

ok claudio

diff --git a/usr.sbin/bgpd/rde_update.c b/usr.sbin/bgpd/rde_update.c
index eb56875..a0c849e 100644 (file)
--- a/usr.sbin/bgpd/rde_update.c
+++ b/usr.sbin/bgpd/rde_update.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rde_update.c,v 1.138 2022/03/22 10:53:08 claudio Exp $ */
+/*     $OpenBSD: rde_update.c,v 1.139 2022/03/30 16:06:32 tb Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -117,12 +117,7 @@ up_generate_updates(struct filter_head *rules, struct rde_peer *peer,
                prefixlen = new->pt->prefixlen;
        }
 
-again:
-       if (new == NULL) {
-               /* withdraw prefix */
-               if ((p = prefix_adjout_get(peer, 0, &addr, prefixlen)) != NULL)
-                       prefix_adjout_withdraw(p);
-       } else {
+       while (new != NULL) {
                need_withdraw = 0;
                /*
                 * up_test_update() needs to run before the output filters
@@ -142,10 +137,8 @@ again:
                 * skip the filters.
                 */
                if (need_withdraw &&
-                   !(peer->flags & PEERFLAG_EVALUATE_ALL)) {
-                       new = NULL;
-                       goto again;
-               }
+                   !(peer->flags & PEERFLAG_EVALUATE_ALL))
+                       break;
 
                rde_filterstate_prep(&state, prefix_aspath(new),
                    prefix_communities(new), prefix_nexthop(new),
@@ -153,19 +146,19 @@ again:
                if (rde_filter(rules, peer, prefix_peer(new), &addr,
                    prefixlen, prefix_vstate(new), &state) == ACTION_DENY) {
                        rde_filterstate_clean(&state);
-                       if (peer->flags & PEERFLAG_EVALUATE_ALL)
+                       if (peer->flags & PEERFLAG_EVALUATE_ALL) {
                                new = TAILQ_NEXT(new, entry.list.rib);
-                       else
-                               new = NULL;
-                       if (new != NULL && !prefix_eligible(new))
-                               new = NULL;
-                       goto again;
+                               if (new != NULL && prefix_eligible(new))
+                                       continue;
+                       }
+                       break;
                }
 
-               if (need_withdraw) {
-                       new = NULL;
-                       goto again;
-               }
+               /* check if this was actually a withdraw */
+               if (need_withdraw)
+                       break;
+
+               /* from here on we know this is an update */
 
                up_prep_adjout(peer, &state, addr.aid);
                prefix_adjout_update(peer, &state, &addr,
@@ -181,7 +174,13 @@ again:
                        rde_update_err(peer, ERR_CEASE,
                            ERR_CEASE_MAX_SENT_PREFIX, NULL, 0);
                }
+
+               return;
        }
+
+       /* withdraw prefix */
+       if ((p = prefix_adjout_get(peer, 0, &addr, prefixlen)) != NULL)
+               prefix_adjout_withdraw(p);
 }
 
 struct rib_entry *rib_add(struct rib *, struct bgpd_addr *, int);