Fix how the rde_eval_all flag is tracked. Make sure it is correctly set

when a new peer shows up or during a reload. Tracking this during runtime
just does not work reliably (especially  for reloads).
Problem noticed and fix tested by Pier Carlo Chiodi

diff --git a/usr.sbin/bgpd/rde.c b/usr.sbin/bgpd/rde.c
index 3c88cde..34b99af 100644 (file)
--- a/usr.sbin/bgpd/rde.c
+++ b/usr.sbin/bgpd/rde.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: rde.c,v 1.521 2021/05/25 14:18:44 claudio Exp $ */
+/*     $OpenBSD: rde.c,v 1.522 2021/05/27 08:38:42 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -113,6 +113,7 @@ volatile sig_atomic_t        rde_quit = 0;
 struct filter_head     *out_rules, *out_rules_tmp;
 struct rde_memstats     rdemem;
 int                     softreconfig;
+static int              rde_eval_all;
 
 extern struct rde_peer_head     peerlist;
 extern struct rde_peer         *peerself;
@@ -400,6 +401,9 @@ rde_dispatch_imsg_session(struct imsgbuf *ibuf)
                                fatalx("incorrect size of session request");
                        memcpy(&pconf, imsg.data, sizeof(pconf));
                        peer_add(imsg.hdr.peerid, &pconf);
+                       /* make sure rde_eval_all is on if needed. */
+                       if (pconf.flags & PEERFLAG_EVALUATE_ALL)
+                               rde_eval_all = 1;
                        break;
                case IMSG_NETWORK_ADD:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE !=
@@ -2868,8 +2872,6 @@ rde_send_kroute(struct rib *rib, struct prefix *new, struct prefix *old)
 /*
  * update specific functions
  */
-static int rde_eval_all;
-
 int
 rde_evaluate_all(void)
 {
@@ -2899,17 +2901,13 @@ rde_generate_updates(struct rib *rib, struct prefix *new, struct prefix *old,
        else
                aid = old->pt->aid;
 
-       rde_eval_all = 0;
        LIST_FOREACH(peer, &peerlist, peer_l) {
                /* skip ourself */
                if (peer == peerself)
                        continue;
                if (peer->state != PEER_UP)
                        continue;
-               /* handle evaluate all, keep track if it is needed */
-               if (peer->flags & PEERFLAG_EVALUATE_ALL)
-                       rde_eval_all = 1;
-               else if (eval_all)
+               if ((peer->flags & PEERFLAG_EVALUATE_ALL) == 0 && eval_all)
                        /* skip default peers if the best path didn't change */
                        continue;
                /* skip peers using a different rib */
@@ -3271,9 +3269,12 @@ rde_reload_done(void)
 
        rde_filter_calc_skip_steps(out_rules);
 
+       /* make sure that rde_eval_all is correctly set after a config change */
+       rde_eval_all = 0;
+
        /* check if filter changed */
        LIST_FOREACH(peer, &peerlist, peer_l) {
-               if (peer->conf.id == 0)
+               if (peer->conf.id == 0) /* ignore peerself*/
                        continue;
                peer->reconf_out = 0;
                peer->reconf_rib = 0;
@@ -3303,6 +3304,8 @@ rde_reload_done(void)
                }
                peer->export_type = peer->conf.export_type;
                peer->flags = peer->conf.flags;
+               if (peer->flags & PEERFLAG_EVALUATE_ALL)
+                       rde_eval_all = 1;
 
                if (peer->reconf_rib) {
                        if (prefix_dump_new(peer, AID_UNSPEC,
@@ -3320,6 +3323,7 @@ rde_reload_done(void)
                        peer->reconf_out = 1;
                }
        }
+
        /* bring ribs in sync */
        for (rid = 0; rid < rib_size; rid++) {
                struct rib *rib = rib_byid(rid);