add QoS to ignore local readers/writers (#78)

Adds a new "ignorelocal" QoS to the readers/writers to ignore local
matching readers/writers, with three settings:

* DDS_IGNORELOCAL_NONE: default
* DDS_IGNORELOCAL_PARTICIPANT: ignores readers/writers in the same
  participant
* DDS_IGNORELOCAL_PROCESS: ignores readers/writers in the same process

These can be set/got using dds_qset_ignorelocal and
dds_qget_ignorelocal.

If a matching reader or writer is ignored because of this setting, it is
as-if that reader or writer doesn't exist.  No traffic will be generated
or data retained on its behalf.

There are no consequences for interoperability as this is (by
definition) a local affair.

Signed-off-by: Erik Boasson <eb@ilities.com>

src/core/ddsi/include/dds/ddsi/q_xqos.h

@@ -205,6 +205,16 @@ typedef struct nn_share_qospolicy {
   char *name;
 } nn_share_qospolicy_t;
 
+typedef enum nn_ignorelocal_kind {
+  NN_NONE_IGNORELOCAL_QOS,
+  NN_PARTICIPANT_IGNORELOCAL_QOS,
+  NN_PROCESS_IGNORELOCAL_QOS
+} nn_ignorelocal_kind_t;
+
+typedef struct nn_ignorelocal_qospolicy {
+  nn_ignorelocal_kind_t value;
+} nn_ignorelocal_qospolicy_t;
+
 /***/
 
 /* Qos Present bit indices */
@@ -237,6 +247,7 @@ typedef struct nn_share_qospolicy {
 #define QP_PRISMTECH_ENTITY_FACTORY          ((uint64_t)1 << 27)
 #define QP_PRISMTECH_SYNCHRONOUS_ENDPOINT    ((uint64_t)1 << 28)
 #define QP_RTI_TYPECODE                      ((uint64_t)1 << 29)
+#define QP_CYCLONE_IGNORELOCAL               ((uint64_t)1 << 30)
 
 /* Partition QoS is not RxO according to the specification (DDS 1.2,
    section 7.1.3), but communication will not take place unless it
@@ -290,6 +301,7 @@ typedef struct nn_xqos {
   /*x xR*/nn_reader_lifespan_qospolicy_t reader_lifespan;
   /*x xR*/nn_share_qospolicy_t share;
   /*xxx */nn_synchronous_endpoint_qospolicy_t synchronous_endpoint;
+  /* x  */nn_ignorelocal_qospolicy_t ignorelocal;
 
   /*   X*/nn_octetseq_t rti_typecode;
 } nn_xqos_t;

src/core/ddsi/src/q_entity.c

@@ -2058,12 +2058,39 @@ static void connect_proxy_writer_with_reader (struct proxy_writer *pwr, struct r
   proxy_writer_add_connection (pwr, rd, tnow, init_count);
 }
 
+static bool ignore_local_p (const nn_guid_t *guid1, const nn_guid_t *guid2, const struct nn_xqos *xqos1, const struct nn_xqos *xqos2)
+{
+  assert (xqos1->present & QP_CYCLONE_IGNORELOCAL);
+  assert (xqos2->present & QP_CYCLONE_IGNORELOCAL);
+  switch (xqos1->ignorelocal.value)
+  {
+    case NN_NONE_IGNORELOCAL_QOS:
+      break;
+    case NN_PARTICIPANT_IGNORELOCAL_QOS:
+      return memcmp (&guid1->prefix, &guid2->prefix, sizeof (guid1->prefix)) == 0;
+    case NN_PROCESS_IGNORELOCAL_QOS:
+      return true;
+  }
+  switch (xqos2->ignorelocal.value)
+  {
+    case NN_NONE_IGNORELOCAL_QOS:
+      break;
+    case NN_PARTICIPANT_IGNORELOCAL_QOS:
+      return memcmp (&guid1->prefix, &guid2->prefix, sizeof (guid1->prefix)) == 0;
+    case NN_PROCESS_IGNORELOCAL_QOS:
+      return true;
+  }
+  return false;
+}
+
 static void connect_writer_with_reader (struct writer *wr, struct reader *rd, nn_mtime_t tnow)
 {
   int32_t reason;
   (void)tnow;
   if (!is_local_orphan_endpoint (&wr->e) && (is_builtin_entityid (wr->e.guid.entityid, NN_VENDORID_ECLIPSE) || is_builtin_entityid (rd->e.guid.entityid, NN_VENDORID_ECLIPSE)))
     return;
+  if (ignore_local_p (&wr->e.guid, &rd->e.guid, wr->xqos, rd->xqos))
+    return;
   if ((reason = qos_match_p (rd->xqos, wr->xqos)) >= 0)
   {
     writer_qos_mismatch (wr, (uint32_t)reason);

src/core/ddsi/src/q_plist.c

@@ -2656,6 +2656,9 @@ static void xqos_init_default_common (nn_xqos_t *xqos)
 
   xqos->present |= QP_PRISMTECH_SYNCHRONOUS_ENDPOINT;
   xqos->synchronous_endpoint.value = 0;
+
+  xqos->present |= QP_CYCLONE_IGNORELOCAL;
+  xqos->ignorelocal.value = NN_NONE_IGNORELOCAL_QOS;
 }
 
 void nn_xqos_init_default_reader (nn_xqos_t *xqos)
@@ -2810,6 +2813,7 @@ void nn_xqos_mergein_missing (nn_xqos_t *a, const nn_xqos_t *b)
   CQ (PRISMTECH_READER_LIFESPAN, reader_lifespan);
   CQ (PRISMTECH_ENTITY_FACTORY, entity_factory);
   CQ (PRISMTECH_SYNCHRONOUS_ENDPOINT, synchronous_endpoint);
+  CQ (CYCLONE_IGNORELOCAL, ignorelocal);
 #undef CQ
 
   /* For allocated ones it is Not strictly necessary to use tmp, as
@@ -3197,6 +3201,10 @@ uint64_t nn_xqos_delta (const nn_xqos_t *a, const nn_xqos_t *b, uint64_t mask)
     if (octetseqs_differ (&a->rti_typecode, &b->rti_typecode))
       delta |= QP_RTI_TYPECODE;
   }
+  if (check & QP_CYCLONE_IGNORELOCAL) {
+    if (a->ignorelocal.value != b->ignorelocal.value)
+      delta |= QP_CYCLONE_IGNORELOCAL;
+  }
   return delta;
 }
 
@@ -3257,6 +3265,7 @@ void nn_xqos_addtomsg (struct nn_xmsg *m, const nn_xqos_t *xqos, uint64_t wanted
   SIMPLE (PRISMTECH_ENTITY_FACTORY, entity_factory);
   SIMPLE (PRISMTECH_SYNCHRONOUS_ENDPOINT, synchronous_endpoint);
   FUNC_BY_REF (RTI_TYPECODE, rti_typecode, octetseq);
+  /* CYCLONE_IGNORELOCAL is not visible on the wire */
 #undef FUNC_BY_REF
 #undef FUNC_BY_VAL
 #undef SIMPLE
@@ -3467,6 +3476,7 @@ void nn_log_xqos (uint32_t cat, const nn_xqos_t *xqos)
     log_octetseq (cat, xqos->rti_typecode.length, xqos->rti_typecode.value);
     DDS_LOG(cat, ">");
   });
+  DO (CYCLONE_IGNORELOCAL, { LOGB1 ("ignorelocal=%u", xqos->ignorelocal.value); });
 
 #undef PRINTARG_DUR
 #undef FMT_DUR