From 2791ccbe02362bd4faaf6b6b860e81c6ae7ff3ac Mon Sep 17 00:00:00 2001
From: "W.C.A. Wijngaards" <wouter@nlnetlabs.nl>
Date: Fri, 18 Aug 2023 09:11:06 +0200
Subject: [PATCH] - Fix for iter_dec_attempts that could cause a hang, part of 
  capsforid and qname minimisation, depending on the settings.

---
 iterator/iter_delegpt.c | 39 +++++++++++++++++++++++++++++++++++++++
 iterator/iter_delegpt.h | 25 +++++++++++++++++++++++++
 iterator/iter_utils.c   |  3 +--
 3 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/iterator/iter_delegpt.c b/iterator/iter_delegpt.c
index fd07aaa13..c8b9a3ffe 100644
--- a/iterator/iter_delegpt.c
+++ b/iterator/iter_delegpt.c
@@ -321,6 +321,45 @@ void delegpt_log(enum verbosity_value v, struct delegpt* dp)
 	}
 }
 
+int
+delegpt_addr_on_result_list(struct delegpt* dp, struct delegpt_addr* find)
+{
+	struct delegpt_addr* a = dp->result_list;
+	while(a) {
+		if(a == find)
+			return 1;
+		a = a->next_result;
+	}
+	return 0;
+}
+
+void
+delegpt_usable_list_remove_addr(struct delegpt* dp, struct delegpt_addr* del)
+{
+	struct delegpt_addr* usa = dp->usable_list, *prev = NULL;
+	while(usa) {
+		if(usa == del) {
+			/* snip off the usable list */
+			if(prev)
+				prev->next_usable = usa->next_usable;
+			else	dp->usable_list = usa->next_usable;
+			return;
+		}
+		prev = usa;
+		usa = usa->next_usable;
+	}
+}
+
+void
+delegpt_add_to_result_list(struct delegpt* dp, struct delegpt_addr* a)
+{
+	if(delegpt_addr_on_result_list(dp, a))
+		return;
+	delegpt_usable_list_remove_addr(dp, a);
+	a->next_result = dp->result_list;
+	dp->result_list = a;
+}
+
 void 
 delegpt_add_unused_targets(struct delegpt* dp)
 {
diff --git a/iterator/iter_delegpt.h b/iterator/iter_delegpt.h
index 586597a69..49f6f6b81 100644
--- a/iterator/iter_delegpt.h
+++ b/iterator/iter_delegpt.h
@@ -457,4 +457,29 @@ int delegpt_add_target_mlc(struct delegpt* dp, uint8_t* name, size_t namelen,
 /** get memory in use by dp */
 size_t delegpt_get_mem(struct delegpt* dp);
 
+/**
+ * See if the addr is on the result list.
+ * @param dp: delegation point.
+ * @param find: the pointer is searched for on the result list.
+ * @return 1 if found, 0 if not found.
+ */
+int delegpt_addr_on_result_list(struct delegpt* dp, struct delegpt_addr* find);
+
+/**
+ * Remove the addr from the usable list.
+ * @param dp: the delegation point.
+ * @param del: the addr to remove from the list, the pointer is searched for.
+ */
+void delegpt_usable_list_remove_addr(struct delegpt* dp,
+	struct delegpt_addr* del);
+
+/**
+ * Add the delegpt_addr back to the result list, if it is not already on
+ * the result list. Also removes it from the usable list.
+ * @param dp: delegation point.
+ * @param a: addr to add, nothing happens if it is already on the result list.
+ *	It is removed from the usable list.
+ */
+void delegpt_add_to_result_list(struct delegpt* dp, struct delegpt_addr* a);
+
 #endif /* ITERATOR_ITER_DELEGPT_H */
diff --git a/iterator/iter_utils.c b/iterator/iter_utils.c
index 961f76241..10a8ec3eb 100644
--- a/iterator/iter_utils.c
+++ b/iterator/iter_utils.c
@@ -1346,8 +1346,7 @@ void iter_dec_attempts(struct delegpt* dp, int d, int outbound_msg_retry)
 	for(a=dp->target_list; a; a = a->next_target) {
 		if(a->attempts >= outbound_msg_retry) {
 			/* add back to result list */
-			a->next_result = dp->result_list;
-			dp->result_list = a;
+			delegpt_add_to_result_list(dp, a);
 		}
 		if(a->attempts > d)
 			a->attempts -= d;