From: claudio <claudio@openbsd.org>
Date: Tue, 1 Mar 2022 09:46:22 +0000 (+0000)
Subject: Rewrite some comments to hopefully be easier to understand.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=591142c4598a6a0f1610de3339e87106e94adb53;p=openbsd

Rewrite some comments to hopefully be easier to understand.
No code change.
---

diff --git a/usr.sbin/bgpd/rde_decide.c b/usr.sbin/bgpd/rde_decide.c
index 9c427589b55..3a0f6eb7f1f 100644
--- a/usr.sbin/bgpd/rde_decide.c
+++ b/usr.sbin/bgpd/rde_decide.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_decide.c,v 1.87 2022/02/06 09:51:19 claudio Exp $ */
+/*	$OpenBSD: rde_decide.c,v 1.88 2022/03/01 09:46:22 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Claudio Jeker <claudio@openbsd.org>
@@ -281,7 +281,7 @@ prefix_cmp(struct prefix *p1, struct prefix *p2, int *testall)
 	if (i > 0)
 		return -1;
 
-	/* XXX RFC7911 does not specify this but it is needed. */
+	/* RFC7911 does not specify this but something like this is needed. */
 	/* 13. lowest path identifier wins */
 	if (p1->path_id < p2->path_id)
 		return 1;
@@ -305,7 +305,7 @@ prefix_insert(struct prefix *new, struct prefix *ep, struct rib_entry *re)
 	struct prefix *xp, *np, *tailp = NULL, *insertp = ep;
 	int testall, selected = 0;
 
-	/* start scan at the entry point (ep) or if the head if ep == NULL */
+	/* start scan at the entry point (ep) or the head if ep == NULL */
 	if (ep == NULL)
 		ep = LIST_FIRST(&re->prefix_h);
 
@@ -339,10 +339,13 @@ prefix_insert(struct prefix *new, struct prefix *ep, struct rib_entry *re)
 			}
 		} else {
 			/*
-			 * p is less preferred, remember insertion point
-			 * If p got selected during a testall traverse 
-			 * do not alter the insertion point unless this
-			 * happened on an actual MED check.
+			 * xp is preferred over new.
+			 * Remember insertion point for later unless the
+			 * traverse is just looking for a possible MED
+			 * inversion (selected == 1).
+			 * If the last comparison's tie-breaker was the MED
+			 * check reset selected and with it insertp since
+			 * this was an actual MED priority inversion.
 			 */
 			if (testall == 2)
 				selected = 0;