Move literally everything out of src/or

This commit won't build yet -- it just puts everything in a slightly
more logical place.

The reasoning here is that "src/core" will hold the stuff that every (or
nearly every) tor instance will need in order to do onion routing.
Other features (including some necessary ones) will live in
"src/feature".  The "src/app" directory will hold the stuff needed
to have Tor be an application you can actually run.

This commit DOES NOT refactor the former contents of src/or into a
logical set of acyclic libraries, or change any code at all.  That
will have to come in the future.

We will continue to move things around and split them in the future,
but I hope this lays a reasonable groundwork for doing so.

1 files changed, 175 insertions, 0 deletions

diff --git a/src/core/or/scheduler_vanilla.c b/src/core/or/scheduler_vanilla.c
new file mode 100644
index 0000000000..e05bebb37c
--- /dev/null
+++ b/src/core/or/scheduler_vanilla.c
@@ -0,0 +1,175 @@
+/* Copyright (c) 2017-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "or/or.h"
+#include "or/config.h"
+#define TOR_CHANNEL_INTERNAL_
+#include "or/channel.h"
+#define SCHEDULER_PRIVATE_
+#include "or/scheduler.h"
+
+/*****************************************************************************
+ * Other internal data
+ *****************************************************************************/
+
+/* Maximum cells to flush in a single call to channel_flush_some_cells(); */
+#define MAX_FLUSH_CELLS 1000
+
+/*****************************************************************************
+ * Externally called function implementations
+ *****************************************************************************/
+
+/* Return true iff the scheduler has work to perform. */
+static int
+have_work(void)
+{
+  smartlist_t *cp = get_channels_pending();
+  IF_BUG_ONCE(!cp) {
+    return 0; // channels_pending doesn't exist so... no work?
+  }
+  return smartlist_len(cp) > 0;
+}
+
+/** Re-trigger the scheduler in a way safe to use from the callback */
+
+static void
+vanilla_scheduler_schedule(void)
+{
+  if (!have_work()) {
+    return;
+  }
+
+  /* Activate our event so it can process channels. */
+  scheduler_ev_active();
+}
+
+static void
+vanilla_scheduler_run(void)
+{
+  int n_cells, n_chans_before, n_chans_after;
+  ssize_t flushed, flushed_this_time;
+  smartlist_t *cp = get_channels_pending();
+  smartlist_t *to_readd = NULL;
+  channel_t *chan = NULL;
+
+  log_debug(LD_SCHED, "We have a chance to run the scheduler");
+
+  n_chans_before = smartlist_len(cp);
+
+  while (smartlist_len(cp) > 0) {
+    /* Pop off a channel */
+    chan = smartlist_pqueue_pop(cp,
+                                scheduler_compare_channels,
+                                offsetof(channel_t, sched_heap_idx));
+    IF_BUG_ONCE(!chan) {
+      /* Some-freaking-how a NULL got into the channels_pending. That should
+       * never happen, but it should be harmless to ignore it and keep looping.
+       */
+      continue;
+    }
+
+    /* Figure out how many cells we can write */
+    n_cells = channel_num_cells_writeable(chan);
+    if (n_cells > 0) {
+      log_debug(LD_SCHED,
+                "Scheduler saw pending channel %"PRIu64 " at %p with "
+                "%d cells writeable",
+                (chan->global_identifier), chan, n_cells);
+
+      flushed = 0;
+      while (flushed < n_cells) {
+        flushed_this_time =
+          channel_flush_some_cells(chan,
+                        MIN(MAX_FLUSH_CELLS, (size_t) n_cells - flushed));
+        if (flushed_this_time <= 0) break;
+        flushed += flushed_this_time;
+      }
+
+      if (flushed < n_cells) {
+        /* We ran out of cells to flush */
+        scheduler_set_channel_state(chan, SCHED_CHAN_WAITING_FOR_CELLS);
+      } else {
+        /* The channel may still have some cells */
+        if (channel_more_to_flush(chan)) {
+        /* The channel goes to either pending or waiting_to_write */
+          if (channel_num_cells_writeable(chan) > 0) {
+            /* Add it back to pending later */
+            if (!to_readd) to_readd = smartlist_new();
+            smartlist_add(to_readd, chan);
+            log_debug(LD_SCHED,
+                      "Channel %"PRIu64 " at %p "
+                      "is still pending",
+                      (chan->global_identifier),
+                      chan);
+          } else {
+            /* It's waiting to be able to write more */
+            scheduler_set_channel_state(chan, SCHED_CHAN_WAITING_TO_WRITE);
+          }
+        } else {
+          /* No cells left; it can go to idle or waiting_for_cells */
+          if (channel_num_cells_writeable(chan) > 0) {
+            /*
+             * It can still accept writes, so it goes to
+             * waiting_for_cells
+             */
+            scheduler_set_channel_state(chan, SCHED_CHAN_WAITING_FOR_CELLS);
+          } else {
+            /*
+             * We exactly filled up the output queue with all available
+             * cells; go to idle.
+             */
+            scheduler_set_channel_state(chan, SCHED_CHAN_IDLE);
+          }
+        }
+      }
+
+      log_debug(LD_SCHED,
+                "Scheduler flushed %d cells onto pending channel "
+                "%"PRIu64 " at %p",
+                (int)flushed, (chan->global_identifier),
+                chan);
+    } else {
+      log_info(LD_SCHED,
+               "Scheduler saw pending channel %"PRIu64 " at %p with "
+               "no cells writeable",
+               (chan->global_identifier), chan);
+      /* Put it back to WAITING_TO_WRITE */
+      scheduler_set_channel_state(chan, SCHED_CHAN_WAITING_TO_WRITE);
+    }
+  }
+
+  /* Readd any channels we need to */
+  if (to_readd) {
+    SMARTLIST_FOREACH_BEGIN(to_readd, channel_t *, readd_chan) {
+      scheduler_set_channel_state(readd_chan, SCHED_CHAN_PENDING);
+      smartlist_pqueue_add(cp,
+                           scheduler_compare_channels,
+                           offsetof(channel_t, sched_heap_idx),
+                           readd_chan);
+    } SMARTLIST_FOREACH_END(readd_chan);
+    smartlist_free(to_readd);
+  }
+
+  n_chans_after = smartlist_len(cp);
+  log_debug(LD_SCHED, "Scheduler handled %d of %d pending channels",
+            n_chans_before - n_chans_after, n_chans_before);
+}
+
+/* Stores the vanilla scheduler function pointers. */
+static scheduler_t vanilla_scheduler = {
+  .type = SCHEDULER_VANILLA,
+  .free_all = NULL,
+  .on_channel_free = NULL,
+  .init = NULL,
+  .on_new_consensus = NULL,
+  .schedule = vanilla_scheduler_schedule,
+  .run = vanilla_scheduler_run,
+  .on_new_options = NULL,
+};
+
+scheduler_t *
+get_vanilla_scheduler(void)
+{
+  return &vanilla_scheduler;
+}
+