ANSN Check must be skipped if we reset the sequence number of a router

OLSR · Jun 11, 2021 · e1e49c0 · e1e49c0
1 parent 06b8343
commit e1e49c0
Show file tree

Hide file tree

Showing 5 changed files with 16 additions and 7 deletions.
diff --git a/include/oonf/base/oonf_duplicate_set.h b/include/oonf/base/oonf_duplicate_set.h
@@ -86,6 +86,9 @@ enum oonf_duplicate_result
   /*! newer than the latest cached number */
   OONF_DUPSET_NEWEST,
 
+  /*! sequence number was reset */
+  OONF_DUPSET_RESET,
+
   /*! sequence number was the first tested with the duplicate set */
   OONF_DUPSET_FIRST,
 };
@@ -180,7 +183,7 @@ EXPORT const char *oonf_duplicate_get_result_str(enum oonf_duplicate_result);
  */
 static INLINE bool
 oonf_duplicate_is_new(enum oonf_duplicate_result result) {
-  return result == OONF_DUPSET_NEW || result == OONF_DUPSET_NEWEST || result == OONF_DUPSET_FIRST;
+  return result == OONF_DUPSET_NEW || result == OONF_DUPSET_NEWEST || result == OONF_DUPSET_RESET || result == OONF_DUPSET_FIRST;
 }
 
 #endif /* OONF_DUPLICATE_SET_H_ */
diff --git a/include/oonf/olsrv2/olsrv2/olsrv2.h b/include/oonf/olsrv2/olsrv2/olsrv2.h
@@ -75,7 +75,7 @@ EXPORT uint64_t olsrv2_get_tc_interval(void);
 EXPORT uint64_t olsrv2_get_tc_validity(void);
 EXPORT bool olsrv2_is_nhdp_routable(struct netaddr *addr);
 EXPORT bool olsrv2_is_routable(struct netaddr *addr);
-EXPORT bool olsrv2_mpr_shall_process(struct rfc5444_reader_tlvblock_context *, uint64_t vtime);
+EXPORT bool olsrv2_mpr_shall_process(struct rfc5444_reader_tlvblock_context *, uint64_t vtime, bool *);
 EXPORT bool olsrv2_mpr_shall_forwarding(
   struct rfc5444_reader_tlvblock_context *context, struct netaddr *source_address, uint64_t vtime);
 EXPORT void olsrv2_generate_tcs(bool);

diff --git a/src/base/oonf_duplicate_set.c b/src/base/oonf_duplicate_set.c
@@ -319,7 +319,7 @@ _test(struct oonf_duplicate_set *dupset, struct oonf_duplicate_entry *entry, uin
       entry->too_old_count = 0;
       entry->current = seqno;
 
-      return OONF_DUPSET_NEWEST;
+      return OONF_DUPSET_RESET;
     }
     return OONF_DUPSET_TOO_OLD;
   }

diff --git a/src/olsrv2/olsrv2/olsrv2.c b/src/olsrv2/olsrv2/olsrv2.c
@@ -384,10 +384,11 @@ olsrv2_is_routable(struct netaddr *addr) {
  * to MPR settings.
  * @param context RFC5444 tlvblock reader context
  * @param vtime validity time for duplicate entry data
+ * @param reset pointer to boolean that will tell if the sequence number was reset
  * @return true if TC should be processed, false otherwise
  */
 bool
-olsrv2_mpr_shall_process(struct rfc5444_reader_tlvblock_context *context, uint64_t vtime) {
+olsrv2_mpr_shall_process(struct rfc5444_reader_tlvblock_context *context, uint64_t vtime, bool *reset) {
   enum oonf_duplicate_result dup_result;
   bool process;
 #ifdef OONF_LOG_DEBUG_INFO
@@ -407,6 +408,9 @@ olsrv2_mpr_shall_process(struct rfc5444_reader_tlvblock_context *context, uint64
   dup_result = oonf_duplicate_entry_add(&_protocol->processed_set, context->msg_type, &context->orig_addr,
     context->seqno, vtime + _olsrv2_config.f_hold_time);
   process = oonf_duplicate_is_new(dup_result);
+  if (reset != NULL) {
+    *reset = dup_result == OONF_DUPSET_RESET;
+  }
 
   OONF_DEBUG(LOG_OLSRV2,
     "Do %sprocess message type %u from %s"

diff --git a/src/olsrv2/olsrv2/olsrv2_reader.c b/src/olsrv2/olsrv2/olsrv2_reader.c
@@ -215,6 +215,7 @@ _cb_messagetlvs(struct rfc5444_reader_tlvblock_context *context) {
   uint16_t ansn;
   uint8_t tmp;
   int af_type;
+  bool seqno_reset;
 #ifdef OONF_LOG_DEBUG_INFO
   struct netaddr_str buf;
 #endif
@@ -295,7 +296,8 @@ _cb_messagetlvs(struct rfc5444_reader_tlvblock_context *context) {
   }
 
   /* test if we already processed the message */
-  if (!olsrv2_mpr_shall_process(context, _current.vtime)) {
+  seqno_reset = false;
+  if (!olsrv2_mpr_shall_process(context, _current.vtime, &seqno_reset)) {
     OONF_DEBUG(LOG_OLSRV2_R, "Processing set says 'do not process'");
     return RFC5444_DROP_MSG_BUT_FORWARD;
   }
@@ -309,13 +311,13 @@ _cb_messagetlvs(struct rfc5444_reader_tlvblock_context *context) {
 
   /* check if the topology information is recent enough */
   if (_current.complete_tc) {
-    if (rfc5444_seqno_is_smaller(ansn, _current.node->ansn)) {
+    if (!seqno_reset && rfc5444_seqno_is_smaller(ansn, _current.node->ansn)) {
       OONF_DEBUG(LOG_OLSRV2_R, "ANSN %u is smaller than last stored ANSN %u", ansn, _current.node->ansn);
       return RFC5444_DROP_MSG_BUT_FORWARD;
     }
   }
   else {
-    if (!rfc5444_seqno_is_larger(ansn, _current.node->ansn)) {
+    if (!seqno_reset && !rfc5444_seqno_is_larger(ansn, _current.node->ansn)) {
       OONF_DEBUG(LOG_OLSRV2_R, "ANSN %u is smaller than last stored ANSN %u", ansn, _current.node->ansn);
       return RFC5444_DROP_MSG_BUT_FORWARD;
     }