VPP-598: tcp stack initial commit

Change-Id: I49e5ce0aae6e4ff634024387ceaf7dbc432a0351
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 568 insertions, 0 deletions

diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
new file mode 100644
index 00000000000..11f901931be
--- /dev/null
+++ b/src/svm/svm_fifo.c
@@ -0,0 +1,568 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "svm_fifo.h"
+
+/** create an svm fifo, in the current heap. Fails vs blow up the process */
+svm_fifo_t *
+svm_fifo_create (u32 data_size_in_bytes)
+{
+  svm_fifo_t *f;
+  pthread_mutexattr_t attr;
+  pthread_condattr_t cattr;
+
+  f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
+				      CLIB_CACHE_LINE_BYTES);
+  if (f == 0)
+    return 0;
+
+  memset (f, 0, sizeof (*f) + data_size_in_bytes);
+  f->nitems = data_size_in_bytes;
+  f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
+
+  memset (&attr, 0, sizeof (attr));
+  memset (&cattr, 0, sizeof (cattr));
+
+  if (pthread_mutexattr_init (&attr))
+    clib_unix_warning ("mutexattr_init");
+  if (pthread_mutexattr_setpshared (&attr, PTHREAD_PROCESS_SHARED))
+    clib_unix_warning ("pthread_mutexattr_setpshared");
+  if (pthread_mutex_init (&f->mutex, &attr))
+    clib_unix_warning ("mutex_init");
+  if (pthread_mutexattr_destroy (&attr))
+    clib_unix_warning ("mutexattr_destroy");
+  if (pthread_condattr_init (&cattr))
+    clib_unix_warning ("condattr_init");
+  if (pthread_condattr_setpshared (&cattr, PTHREAD_PROCESS_SHARED))
+    clib_unix_warning ("condattr_setpshared");
+  if (pthread_cond_init (&f->condvar, &cattr))
+    clib_unix_warning ("cond_init1");
+  if (pthread_condattr_destroy (&cattr))
+    clib_unix_warning ("cond_init2");
+
+  return (f);
+}
+
+always_inline ooo_segment_t *
+ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
+{
+  ooo_segment_t *s;
+
+  pool_get (f->ooo_segments, s);
+
+  s->fifo_position = start;
+  s->length = length;
+
+  s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
+
+  return s;
+}
+
+always_inline void
+ooo_segment_del (svm_fifo_t * f, u32 index)
+{
+  ooo_segment_t *cur, *prev = 0, *next = 0;
+  cur = pool_elt_at_index (f->ooo_segments, index);
+
+  if (cur->next != OOO_SEGMENT_INVALID_INDEX)
+    {
+      next = pool_elt_at_index (f->ooo_segments, cur->next);
+      next->prev = cur->prev;
+    }
+
+  if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
+    {
+      prev = pool_elt_at_index (f->ooo_segments, cur->prev);
+      prev->next = cur->next;
+    }
+  else
+    {
+      f->ooos_list_head = cur->next;
+    }
+
+  pool_put (f->ooo_segments, cur);
+}
+
+/**
+ * Add segment to fifo's out-of-order segment list. Takes care of merging
+ * adjacent segments and removing overlapping ones.
+ */
+static void
+ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length)
+{
+  ooo_segment_t *s, *new_s, *prev, *next, *it;
+  u32 new_index, position, end_offset, s_sof, s_eof, s_index;
+
+  position = (f->tail + offset) % f->nitems;
+  end_offset = offset + length;
+
+  if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
+    {
+      s = ooo_segment_new (f, position, length);
+      f->ooos_list_head = s - f->ooo_segments;
+      f->ooos_newest = f->ooos_list_head;
+      return;
+    }
+
+  /* Find first segment that starts after new segment */
+  s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
+  while (s->next != OOO_SEGMENT_INVALID_INDEX
+	 && ooo_segment_offset (f, s) <= offset)
+    s = pool_elt_at_index (f->ooo_segments, s->next);
+
+  s_index = s - f->ooo_segments;
+  s_sof = ooo_segment_offset (f, s);
+  s_eof = ooo_segment_end_offset (f, s);
+
+  /* No overlap, add before current segment */
+  if (end_offset < s_sof)
+    {
+      new_s = ooo_segment_new (f, position, length);
+      new_index = new_s - f->ooo_segments;
+
+      /* Pool might've moved, get segment again */
+      s = pool_elt_at_index (f->ooo_segments, s_index);
+
+      if (s->prev != OOO_SEGMENT_INVALID_INDEX)
+	{
+	  new_s->prev = s->prev;
+
+	  prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
+	  prev->next = new_index;
+	}
+      else
+	{
+	  /* New head */
+	  f->ooos_list_head = new_index;
+	}
+
+      new_s->next = s - f->ooo_segments;
+      s->prev = new_index;
+      f->ooos_newest = new_index;
+      return;
+    }
+  /* No overlap, add after current segment */
+  else if (s_eof < offset)
+    {
+      new_s = ooo_segment_new (f, position, length);
+      new_index = new_s - f->ooo_segments;
+
+      /* Pool might've moved, get segment again */
+      s = pool_elt_at_index (f->ooo_segments, s_index);
+
+      if (s->next != OOO_SEGMENT_INVALID_INDEX)
+	{
+	  new_s->next = s->next;
+
+	  next = pool_elt_at_index (f->ooo_segments, new_s->next);
+	  next->prev = new_index;
+	}
+
+      new_s->prev = s - f->ooo_segments;
+      s->next = new_index;
+      f->ooos_newest = new_index;
+
+      return;
+    }
+
+  /*
+   * Merge needed
+   */
+
+  /* Merge at head */
+  if (offset <= s_sof)
+    {
+      /* If we have a previous, check if we overlap */
+      if (s->prev != OOO_SEGMENT_INVALID_INDEX)
+	{
+	  prev = pool_elt_at_index (f->ooo_segments, s->prev);
+
+	  /* New segment merges prev and current. Remove previous and
+	   * update position of current. */
+	  if (ooo_segment_end_offset (f, prev) >= offset)
+	    {
+	      s->fifo_position = prev->fifo_position;
+	      s->length = s_eof - ooo_segment_offset (f, prev);
+	      ooo_segment_del (f, s->prev);
+	    }
+	}
+      else
+	{
+	  s->fifo_position = position;
+	  s->length = s_eof - ooo_segment_offset (f, s);
+	}
+
+      /* The new segment's tail may cover multiple smaller ones */
+      if (s_eof < end_offset)
+	{
+	  /* Remove segments completely covered */
+	  it = (s->next != OOO_SEGMENT_INVALID_INDEX) ?
+	    pool_elt_at_index (f->ooo_segments, s->next) : 0;
+	  while (it && ooo_segment_end_offset (f, it) < end_offset)
+	    {
+	      next = (it->next != OOO_SEGMENT_INVALID_INDEX) ?
+		pool_elt_at_index (f->ooo_segments, it->next) : 0;
+	      ooo_segment_del (f, it - f->ooo_segments);
+	      it = next;
+	    }
+
+	  /* Update length. Segment's start might have changed. */
+	  s->length = end_offset - ooo_segment_offset (f, s);
+
+	  /* If partial overlap with last, merge */
+	  if (it && ooo_segment_offset (f, it) < end_offset)
+	    {
+	      s->length +=
+		it->length - (ooo_segment_offset (f, it) - end_offset);
+	      ooo_segment_del (f, it - f->ooo_segments);
+	    }
+	}
+    }
+  /* Last but overlapping previous */
+  else if (s_eof <= end_offset)
+    {
+      s->length = end_offset - ooo_segment_offset (f, s);
+    }
+  /* New segment completely covered by current one */
+  else
+    {
+      /* Do Nothing */
+    }
+
+  /* Most recently updated segment */
+  f->ooos_newest = s - f->ooo_segments;
+}
+
+/**
+ * Removes segments that can now be enqueued because the fifo's tail has
+ * advanced. Returns the number of bytes added to tail.
+ */
+static int
+ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued)
+{
+  ooo_segment_t *s;
+  u32 index, bytes = 0, diff;
+
+  s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
+
+  /* If last tail update overlaps one/multiple ooo segments, remove them */
+  diff = (f->nitems + f->tail - s->fifo_position) % f->nitems;
+  while (0 < diff && diff < n_bytes_enqueued)
+    {
+      /* Segment end is beyond the tail. Advance tail and be done */
+      if (diff < s->length)
+	{
+	  f->tail += s->length - diff;
+	  f->tail %= f->nitems;
+	  break;
+	}
+      /* If we have next go on */
+      else if (s->next != OOO_SEGMENT_INVALID_INDEX)
+	{
+	  index = s - f->ooo_segments;
+	  s = pool_elt_at_index (f->ooo_segments, s->next);
+	  diff = (f->nitems + f->tail - s->fifo_position) % f->nitems;
+	  ooo_segment_del (f, index);
+	}
+      /* End of search */
+      else
+	{
+	  break;
+	}
+    }
+
+  /* If tail is adjacent to an ooo segment, 'consume' it */
+  if (diff == 0)
+    {
+      bytes = ((f->nitems - f->cursize) >= s->length) ? s->length :
+	f->nitems - f->cursize;
+
+      f->tail += bytes;
+      f->tail %= f->nitems;
+
+      ooo_segment_del (f, s - f->ooo_segments);
+    }
+
+  return bytes;
+}
+
+static int
+svm_fifo_enqueue_internal (svm_fifo_t * f,
+			   int pid, u32 max_bytes, u8 * copy_from_here)
+{
+  u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+  u32 cursize, nitems;
+
+  if (PREDICT_FALSE (f->cursize == f->nitems))
+    return -2;			/* fifo stuffed */
+
+  /* read cursize, which can only decrease while we're working */
+  cursize = f->cursize;
+  nitems = f->nitems;
+
+  /* Number of bytes we're going to copy */
+  total_copy_bytes = (nitems - cursize) < max_bytes ?
+    (nitems - cursize) : max_bytes;
+
+  if (PREDICT_TRUE (copy_from_here != 0))
+    {
+      /* Number of bytes in first copy segment */
+      first_copy_bytes = ((nitems - f->tail) < total_copy_bytes)
+	? (nitems - f->tail) : total_copy_bytes;
+
+      clib_memcpy (&f->data[f->tail], copy_from_here, first_copy_bytes);
+      f->tail += first_copy_bytes;
+      f->tail = (f->tail == nitems) ? 0 : f->tail;
+
+      /* Number of bytes in second copy segment, if any */
+      second_copy_bytes = total_copy_bytes - first_copy_bytes;
+      if (second_copy_bytes)
+	{
+	  clib_memcpy (&f->data[f->tail], copy_from_here + first_copy_bytes,
+		       second_copy_bytes);
+	  f->tail += second_copy_bytes;
+	  f->tail = (f->tail == nitems) ? 0 : f->tail;
+	}
+    }
+  else
+    {
+      /* Account for a zero-copy enqueue done elsewhere */
+      ASSERT (max_bytes <= (nitems - cursize));
+      f->tail += max_bytes;
+      f->tail = f->tail % nitems;
+      total_copy_bytes = max_bytes;
+    }
+
+  /* Any out-of-order segments to collect? */
+  if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
+    total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes);
+
+  /* Atomically increase the queue length */
+  __sync_fetch_and_add (&f->cursize, total_copy_bytes);
+
+  return (total_copy_bytes);
+}
+
+int
+svm_fifo_enqueue_nowait (svm_fifo_t * f,
+			 int pid, u32 max_bytes, u8 * copy_from_here)
+{
+  return svm_fifo_enqueue_internal (f, pid, max_bytes, copy_from_here);
+}
+
+/** Enqueue a future segment.
+ * Two choices: either copies the entire segment, or copies nothing
+ * Returns 0 of the entire segment was copied
+ * Returns -1 if none of the segment was copied due to lack of space
+ */
+
+static int
+svm_fifo_enqueue_with_offset_internal2 (svm_fifo_t * f,
+					int pid,
+					u32 offset,
+					u32 required_bytes,
+					u8 * copy_from_here)
+{
+  u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+  u32 cursize, nitems;
+  u32 tail_plus_offset;
+
+  ASSERT (offset > 0);
+
+  /* read cursize, which can only decrease while we're working */
+  cursize = f->cursize;
+  nitems = f->nitems;
+
+  /* Will this request fit? */
+  if ((required_bytes + offset) > (nitems - cursize))
+    return -1;
+
+  ooo_segment_add (f, offset, required_bytes);
+
+  /* Number of bytes we're going to copy */
+  total_copy_bytes = required_bytes;
+  tail_plus_offset = (f->tail + offset) % nitems;
+
+  /* Number of bytes in first copy segment */
+  first_copy_bytes = ((nitems - tail_plus_offset) < total_copy_bytes)
+    ? (nitems - tail_plus_offset) : total_copy_bytes;
+
+  clib_memcpy (&f->data[tail_plus_offset], copy_from_here, first_copy_bytes);
+
+  /* Number of bytes in second copy segment, if any */
+  second_copy_bytes = total_copy_bytes - first_copy_bytes;
+  if (second_copy_bytes)
+    {
+      tail_plus_offset += first_copy_bytes;
+      tail_plus_offset %= nitems;
+
+      ASSERT (tail_plus_offset == 0);
+
+      clib_memcpy (&f->data[tail_plus_offset],
+		   copy_from_here + first_copy_bytes, second_copy_bytes);
+    }
+
+  return (0);
+}
+
+
+int
+svm_fifo_enqueue_with_offset (svm_fifo_t * f,
+			      int pid,
+			      u32 offset,
+			      u32 required_bytes, u8 * copy_from_here)
+{
+  return svm_fifo_enqueue_with_offset_internal2
+    (f, pid, offset, required_bytes, copy_from_here);
+}
+
+
+static int
+svm_fifo_dequeue_internal2 (svm_fifo_t * f,
+			    int pid, u32 max_bytes, u8 * copy_here)
+{
+  u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+  u32 cursize, nitems;
+
+  if (PREDICT_FALSE (f->cursize == 0))
+    return -2;			/* nothing in the fifo */
+
+  /* read cursize, which can only increase while we're working */
+  cursize = f->cursize;
+  nitems = f->nitems;
+
+  /* Number of bytes we're going to copy */
+  total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+  if (PREDICT_TRUE (copy_here != 0))
+    {
+      /* Number of bytes in first copy segment */
+      first_copy_bytes = ((nitems - f->head) < total_copy_bytes)
+	? (nitems - f->head) : total_copy_bytes;
+      clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
+      f->head += first_copy_bytes;
+      f->head = (f->head == nitems) ? 0 : f->head;
+
+      /* Number of bytes in second copy segment, if any */
+      second_copy_bytes = total_copy_bytes - first_copy_bytes;
+      if (second_copy_bytes)
+	{
+	  clib_memcpy (copy_here + first_copy_bytes,
+		       &f->data[f->head], second_copy_bytes);
+	  f->head += second_copy_bytes;
+	  f->head = (f->head == nitems) ? 0 : f->head;
+	}
+    }
+  else
+    {
+      /* Account for a zero-copy dequeue done elsewhere */
+      ASSERT (max_bytes <= cursize);
+      f->head += max_bytes;
+      f->head = f->head % nitems;
+      cursize -= max_bytes;
+      total_copy_bytes = max_bytes;
+    }
+
+  __sync_fetch_and_sub (&f->cursize, total_copy_bytes);
+
+  return (total_copy_bytes);
+}
+
+int
+svm_fifo_dequeue_nowait (svm_fifo_t * f,
+			 int pid, u32 max_bytes, u8 * copy_here)
+{
+  return svm_fifo_dequeue_internal2 (f, pid, max_bytes, copy_here);
+}
+
+int
+svm_fifo_peek (svm_fifo_t * f, int pid, u32 offset, u32 max_bytes,
+	       u8 * copy_here)
+{
+  u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
+  u32 cursize, nitems;
+
+  if (PREDICT_FALSE (f->cursize == 0))
+    return -2;			/* nothing in the fifo */
+
+  /* read cursize, which can only increase while we're working */
+  cursize = f->cursize;
+  nitems = f->nitems;
+
+  /* Number of bytes we're going to copy */
+  total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+  if (PREDICT_TRUE (copy_here != 0))
+    {
+      /* Number of bytes in first copy segment */
+      first_copy_bytes =
+	((nitems - f->head) < total_copy_bytes) ?
+	(nitems - f->head) : total_copy_bytes;
+      clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
+
+      /* Number of bytes in second copy segment, if any */
+      second_copy_bytes = total_copy_bytes - first_copy_bytes;
+      if (second_copy_bytes)
+	{
+	  clib_memcpy (copy_here + first_copy_bytes, &f->data[0],
+		       second_copy_bytes);
+	}
+    }
+  return total_copy_bytes;
+}
+
+int
+svm_fifo_dequeue_drop (svm_fifo_t * f, int pid, u32 max_bytes)
+{
+  u32 total_drop_bytes, first_drop_bytes, second_drop_bytes;
+  u32 cursize, nitems;
+
+  if (PREDICT_FALSE (f->cursize == 0))
+    return -2;			/* nothing in the fifo */
+
+  /* read cursize, which can only increase while we're working */
+  cursize = f->cursize;
+  nitems = f->nitems;
+
+  /* Number of bytes we're going to drop */
+  total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
+
+  /* Number of bytes in first copy segment */
+  first_drop_bytes =
+    ((nitems - f->head) < total_drop_bytes) ?
+    (nitems - f->head) : total_drop_bytes;
+  f->head += first_drop_bytes;
+  f->head = (f->head == nitems) ? 0 : f->head;
+
+  /* Number of bytes in second drop segment, if any */
+  second_drop_bytes = total_drop_bytes - first_drop_bytes;
+  if (second_drop_bytes)
+    {
+      f->head += second_drop_bytes;
+      f->head = (f->head == nitems) ? 0 : f->head;
+    }
+
+  __sync_fetch_and_sub (&f->cursize, total_drop_bytes);
+
+  return total_drop_bytes;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */