Add test flags to writer

* Dropping samples on initial transmit
* Suppressing asynchronous heartbeats
* Suppressing retransmits
* Ignoring all ACKNACKs

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

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

@@ -300,6 +300,10 @@ struct writer
   unsigned force_md5_keyhash: 1; /* iff 1, when keyhash has to be hashed, no matter the size */
   unsigned retransmitting: 1; /* iff 1, this writer is currently retransmitting */
   unsigned alive: 1; /* iff 1, the writer is alive (lease for this writer is not expired); field may be modified only when holding both wr->e.lock and wr->c.pp->e.lock */
+  unsigned test_ignore_acknack : 1; /* iff 1, the writer ignores all arriving ACKNACK messages */
+  unsigned test_suppress_retransmit : 1; /* iff 1, the writer does not respond to retransmit requests */
+  unsigned test_suppress_heartbeat : 1; /* iff 1, the writer suppresses all periodic heartbeats */
+  unsigned test_drop_outgoing_data : 1; /* iff 1, the writer drops outgoing data, forcing the readers to request a retransmit */
 #ifdef DDSI_INCLUDE_SSM
   unsigned supports_ssm: 1;
   struct addrset *ssm_as;

src/core/ddsi/src/q_entity.c

@@ -3641,6 +3641,10 @@ static void new_writer_guid_common_init (struct writer *wr, const struct ddsi_se
   wr->time_retransmit = 0;
   wr->force_md5_keyhash = 0;
   wr->alive = 1;
+  wr->test_ignore_acknack = 0;
+  wr->test_suppress_retransmit = 0;
+  wr->test_suppress_heartbeat = 0;
+  wr->test_drop_outgoing_data = 0;
   wr->alive_vclock = 0;
   wr->init_burst_size_limit = UINT32_MAX - UINT16_MAX;
   wr->rexmit_burst_size_limit = UINT32_MAX - UINT16_MAX;

src/core/ddsi/src/q_receive.c

@@ -785,6 +785,12 @@ static int handle_AckNack (struct receiver_state *rst, ddsrt_etime_t tnow, const
   }
 
   ddsrt_mutex_lock (&wr->e.lock);
+  if (wr->test_ignore_acknack)
+  {
+    RSTTRACE (" "PGUIDFMT" -> "PGUIDFMT" test_ignore_acknack)", PGUID (src), PGUID (dst));
+    goto out;
+  }
+
   if ((rn = ddsrt_avl_lookup (&wr_readers_treedef, &wr->readers, &src)) == NULL)
   {
     RSTTRACE (" "PGUIDFMT" -> "PGUIDFMT" not a connection)", PGUID (src), PGUID (dst));
@@ -944,6 +950,11 @@ static int handle_AckNack (struct receiver_state *rst, ddsrt_etime_t tnow, const
      hasn't been transmitted ever, the initial transmit should solve
      that issue; if it has, then the timing is terribly unlucky, but
      a future request'll fix it. */
+  if (wr->test_suppress_retransmit && numbits > 0)
+  {
+    RSTTRACE (" test_suppress_retransmit");
+    numbits = 0;
+  }
   enqueued = 1;
   seq_xmit = writer_read_seq_xmit (wr);
   nn_gap_info_init(&gi);

src/core/ddsi/src/q_transmit.c

@@ -1292,6 +1292,17 @@ static int write_sample_eot (struct thread_state1 * const ts1, struct nn_xpack *
       ddsrt_free (plist);
     }
   }
+  else if (wr->test_drop_outgoing_data)
+  {
+    GVTRACE ("test_drop_outgoing_data");
+    writer_update_seq_xmit (wr, seq);
+    ddsrt_mutex_unlock (&wr->e.lock);
+    if (plist != NULL)
+    {
+      ddsi_plist_fini (plist);
+      ddsrt_free (plist);
+    }
+  }
   else if (addrset_empty (wr->as) && (wr->as_group == NULL || addrset_empty (wr->as_group)))
   {
     /* No network destination, so no point in doing all the work involved

src/core/ddsi/src/q_xevent.c

@@ -778,7 +778,13 @@ static void handle_xevk_heartbeat (struct nn_xpack *xp, struct xevent *ev, ddsrt
      and we certainly don't want to hold the lock during that time. */
   if (msg)
   {
-    nn_xpack_addmsg (xp, msg, 0);
+    if (!wr->test_suppress_heartbeat)
+      nn_xpack_addmsg (xp, msg, 0);
+    else
+    {
+      GVTRACE ("test_suppress_heartbeat\n");
+      nn_xmsg_free (msg);
+    }
   }
 }