tls: picotls optimize writes

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I76a1cd516849cfe5bc87ed2b3707c6f2257126d2

2 files changed, 188 insertions, 113 deletions

diff --git a/src/plugins/tlspicotls/tls_picotls.c b/src/plugins/tlspicotls/tls_picotls.c
index 876836675be..84c6d789928 100644
--- a/src/plugins/tlspicotls/tls_picotls.c
+++ b/src/plugins/tlspicotls/tls_picotls.c
@@ -49,7 +49,6 @@ picotls_ctx_free (tls_ctx_t * ctx)
   picotls_ctx_t *ptls_ctx = (picotls_ctx_t *) ctx;
   vec_free (ptls_ctx->rx_content);
   ptls_free (ptls_ctx->tls);
-  vec_free (ptls_ctx->write_content);
   pool_put_index (picotls_main.ctx_pool[ctx->c_thread_index],
 		  ptls_ctx->ptls_ctx_idx);
 }
@@ -271,6 +270,39 @@ picotls_do_handshake (picotls_ctx_t *ptls_ctx, session_t *tcp_session)
 }
 
 static inline int
+ptls_copy_buf_to_fs (ptls_buffer_t *buf, u32 to_copy, svm_fifo_seg_t *fs,
+		     u32 *fs_idx, u32 max_fs)
+{
+  u32 idx = *fs_idx;
+
+  while (to_copy)
+    {
+      if (fs[idx].len <= to_copy)
+	{
+	  clib_memcpy_fast (fs[idx].data, buf->base + (buf->off - to_copy),
+			    fs[idx].len);
+	  to_copy -= fs[idx].len;
+	  idx += 1;
+	  /* no more space in the app's rx fifo */
+	  if (idx == max_fs)
+	    break;
+	}
+      else
+	{
+	  clib_memcpy_fast (fs[idx].data, buf->base + (buf->off - to_copy),
+			    to_copy);
+	  fs[idx].len -= to_copy;
+	  fs[idx].data += to_copy;
+	  to_copy = 0;
+	}
+    }
+
+  *fs_idx = idx;
+
+  return to_copy;
+}
+
+static inline int
 picotls_ctx_read (tls_ctx_t *ctx, session_t *tcp_session)
 {
   picotls_ctx_t *ptls_ctx = (picotls_ctx_t *) ctx;
@@ -378,146 +410,193 @@ final_checks:
   return off;
 }
 
-static inline int
-picotls_content_process (picotls_ctx_t * ptls_ctx, svm_fifo_t * src_fifo,
-			 svm_fifo_t * dst_fifo, int content_len,
-			 int total_record_overhead, int is_no_copy)
+static inline u32
+ptls_compute_deq_len (picotls_ctx_t *ptls_ctx, u32 dst_chunk, u32 src_chunk,
+		      u32 dst_space, u8 *is_nocopy)
 {
-  ptls_buffer_t *buf = &ptls_ctx->write_buffer;
-  int total_length = content_len + total_record_overhead;
-  int to_dst_len;
-  if (is_no_copy)
-    {
-      ptls_buffer_init (buf, svm_fifo_tail (dst_fifo), total_length);
-      ptls_send (ptls_ctx->tls, buf, svm_fifo_head (src_fifo), content_len);
-
-      assert (!buf->is_allocated);
-      assert (buf->base == svm_fifo_tail (dst_fifo));
+  int record_overhead = ptls_get_record_overhead (ptls_ctx->tls);
+  int num_records;
+  u32 deq_len, total_overhead;
 
-      svm_fifo_dequeue_drop (src_fifo, content_len);
-      svm_fifo_enqueue_nocopy (dst_fifo, buf->off);
-      to_dst_len = buf->off;
+  if (dst_chunk >= clib_min (8192, src_chunk + record_overhead))
+    {
+      *is_nocopy = 1;
+      deq_len = clib_min (src_chunk, dst_chunk);
+      num_records = ceil ((f64) deq_len / PTLS_MAX_PLAINTEXT_RECORD_SIZE);
+      total_overhead = num_records * record_overhead;
+      if (deq_len + total_overhead > dst_chunk)
+	deq_len = dst_chunk - total_overhead;
     }
   else
     {
-      assert (!TLS_WRITE_IS_LEFT (ptls_ctx));
-      vec_validate (ptls_ctx->write_content, total_length);
-      ptls_buffer_init (buf, ptls_ctx->write_content, total_length);
-
-      ptls_send (ptls_ctx->tls, buf, svm_fifo_head (src_fifo), content_len);
-      svm_fifo_dequeue_drop (src_fifo, content_len);
-
-      to_dst_len = svm_fifo_enqueue (dst_fifo, buf->off, buf->base);
+      deq_len = clib_min (src_chunk, dst_space);
+      num_records = ceil ((f64) deq_len / PTLS_MAX_PLAINTEXT_RECORD_SIZE);
+      total_overhead = num_records * record_overhead;
+      if (deq_len + total_overhead > dst_space)
+	deq_len = dst_space - total_overhead;
     }
-  ptls_ctx->write_buffer_offset += to_dst_len;
-  return to_dst_len;
+
+  return deq_len;
 }
 
-static inline int
-picotls_ctx_write (tls_ctx_t * ctx, session_t * app_session,
-		   transport_send_params_t * sp)
+static u32
+ptls_app_to_tcp_write (picotls_ctx_t *ptls_ctx, session_t *app_session,
+		       svm_fifo_t *tcp_tx_fifo, u32 max_len)
 {
-  picotls_ctx_t *ptls_ctx = (picotls_ctx_t *) ctx;
-  u32 deq_max, deq_now;
-  u32 enq_max, enq_now;
-  int from_app_len = 0, to_tls_len = 0, is_nocopy = 0;
-  svm_fifo_t *tls_tx_fifo, *app_tx_fifo;
-  session_t *tls_session;
-
-  int record_overhead = ptls_get_record_overhead (ptls_ctx->tls);
-  int num_records, total_overhead;
+  u32 wrote = 0, max_enq, thread_index, app_buf_len, left, ti = 0;
+  int read = 0, rv, i = 0, len, n_tcp_segs = 4, deq_len;
+  const int n_app_segs = 2, min_chunk = 2048;
+  svm_fifo_seg_t app_fs[n_app_segs], tcp_fs[n_tcp_segs];
+  picotls_main_t *pm = &picotls_main;
+  ptls_buffer_t _buf, *buf = &_buf;
+  svm_fifo_t *app_tx_fifo;
+  u8 is_nocopy, *app_buf;
+  u32 first_chunk_len;
 
-  tls_session = session_get_from_handle (ctx->tls_session_handle);
-  tls_tx_fifo = tls_session->tx_fifo;
+  thread_index = app_session->thread_index;
   app_tx_fifo = app_session->tx_fifo;
 
-  if (PREDICT_FALSE (TLS_WRITE_IS_LEFT (ptls_ctx)))
+  len = svm_fifo_segments (app_tx_fifo, 0, app_fs, n_app_segs, max_len);
+  if (len <= 0)
+    return 0;
+
+  n_tcp_segs = svm_fifo_provision_chunks (tcp_tx_fifo, tcp_fs, n_tcp_segs,
+					  1000 + max_len);
+  if (n_tcp_segs <= 0)
+    return 0;
+
+  while ((left = len - read) && ti < n_tcp_segs)
     {
-      enq_max = svm_fifo_max_enqueue_prod (tls_tx_fifo);
-      int to_write = clib_min (enq_max,
-			       ptls_ctx->write_buffer.off -
-			       ptls_ctx->write_buffer_offset);
-      to_tls_len =
-	svm_fifo_enqueue (tls_tx_fifo, to_write, TLS_WRITE_OFFSET (ptls_ctx));
-      if (to_tls_len < 0)
-	{
-	  app_session->flags |= SESSION_F_CUSTOM_TX;
-	  return 0;
-	}
-      ptls_ctx->write_buffer_offset += to_tls_len;
+      /* If we wrote something and are left with few bytes, postpone write
+       * as we may be able to encrypt a bigger chunk next time */
+      if (wrote && left < min_chunk)
+	break;
 
-      if (TLS_WRITE_IS_LEFT (ptls_ctx))
+      /* Avoid short records if possible */
+      if (app_fs[i].len < min_chunk && min_chunk < left)
 	{
-	  app_session->flags |= SESSION_F_CUSTOM_TX;
-	  return to_tls_len;
+	  app_buf_len = app_fs[i].len + app_fs[i + 1].len;
+	  app_buf = pm->rx_bufs[thread_index];
+	  vec_validate (pm->rx_bufs[thread_index], app_buf_len);
+	  clib_memcpy_fast (pm->rx_bufs[thread_index], app_fs[i].data,
+			    app_fs[i].len);
+	  clib_memcpy_fast (pm->rx_bufs[thread_index] + app_fs[i].len,
+			    app_fs[i + 1].data, app_buf_len - app_fs[i].len);
+	  first_chunk_len = app_fs[i].len;
+	  i += 1;
 	}
       else
 	{
-	  ptls_buffer_init (&ptls_ctx->write_buffer, "", 0);
-	  ptls_ctx->write_buffer_offset = 0;
+	  app_buf = app_fs[i].data;
+	  app_buf_len = app_fs[i].len;
+	  first_chunk_len = 0;
 	}
-    }
 
-  deq_max = svm_fifo_max_dequeue_cons (app_tx_fifo);
-  if (!deq_max)
-    return deq_max;
+      is_nocopy = 0;
+      max_enq = tcp_fs[ti].len;
+      max_enq += ti < (n_tcp_segs - 1) ? tcp_fs[ti + 1].len : 0;
 
-  deq_now = clib_min (deq_max, sp->max_burst_size);
-  deq_now = clib_min (deq_now, svm_fifo_max_read_chunk (app_tx_fifo));
+      deq_len = ptls_compute_deq_len (ptls_ctx, tcp_fs[ti].len, app_buf_len,
+				      max_enq, &is_nocopy);
+      if (is_nocopy)
+	{
+	  ptls_buffer_init (buf, tcp_fs[ti].data, tcp_fs[ti].len);
+	  rv = ptls_send (ptls_ctx->tls, buf, app_buf, deq_len);
 
-  enq_max = svm_fifo_max_enqueue_prod (tls_tx_fifo);
-    /** There is no engough enqueue space for one record **/
-  if (enq_max <= record_overhead)
-    {
-      app_session->flags |= SESSION_F_CUSTOM_TX;
-      return 0;
-    }
+	  assert (rv == 0);
+	  wrote += buf->off;
 
-  enq_now = clib_min (enq_max, svm_fifo_max_write_chunk (tls_tx_fifo));
+	  tcp_fs[ti].len -= buf->off;
+	  tcp_fs[ti].data += buf->off;
+	  if (!tcp_fs[ti].len)
+	    ti += 1;
+	}
+      else
+	{
+	  vec_validate (pm->tx_bufs[thread_index], max_enq);
+	  ptls_buffer_init (buf, pm->tx_bufs[thread_index], max_enq);
+	  rv = ptls_send (ptls_ctx->tls, buf, app_buf, deq_len);
 
-    /** Allowed to execute no-copy crypto operation **/
-  if (enq_now > record_overhead)
-    {
-      is_nocopy = 1;
-      from_app_len = clib_min (deq_now, enq_now);
-      num_records =
-	ceil ((f64) from_app_len / PTLS_MAX_PLAINTEXT_RECORD_SIZE);
-      total_overhead = num_records * record_overhead;
-      if (from_app_len + total_overhead > enq_now)
-	from_app_len = enq_now - total_overhead;
+	  assert (rv == 0);
+	  wrote += buf->off;
+
+	  left = ptls_copy_buf_to_fs (buf, buf->off, tcp_fs, &ti, n_tcp_segs);
+	  assert (left == 0);
+	}
+
+      read += deq_len;
+      ASSERT (deq_len >= first_chunk_len);
+
+      if (deq_len == app_buf_len)
+	{
+	  i += 1;
+	}
+      else
+	{
+	  app_fs[i].len -= deq_len - first_chunk_len;
+	  app_fs[i].data += deq_len - first_chunk_len;
+	}
     }
-  else
+
+  if (read)
     {
-      from_app_len = clib_min (deq_now, enq_max);
-      num_records =
-	ceil ((f64) from_app_len / PTLS_MAX_PLAINTEXT_RECORD_SIZE);
-      total_overhead = num_records * record_overhead;
-      if (from_app_len + total_overhead > enq_max)
-	from_app_len = enq_max - total_overhead;
+      svm_fifo_dequeue_drop (app_tx_fifo, read);
+      if (svm_fifo_needs_deq_ntf (app_tx_fifo, read))
+	session_dequeue_notify (app_session);
     }
 
-  to_tls_len =
-    picotls_content_process (ptls_ctx, app_tx_fifo, tls_tx_fifo,
-			     from_app_len, total_overhead, is_nocopy);
-  if (!TLS_WRITE_IS_LEFT (ptls_ctx))
+  if (wrote)
     {
-      ptls_ctx->write_buffer_offset = 0;
-      ptls_buffer_init (&ptls_ctx->write_buffer, "", 0);
+      svm_fifo_enqueue_nocopy (tcp_tx_fifo, wrote);
+      if (svm_fifo_set_event (tcp_tx_fifo))
+	session_send_io_evt_to_thread (tcp_tx_fifo, SESSION_IO_EVT_TX);
     }
 
-  if (svm_fifo_needs_deq_ntf (app_tx_fifo, from_app_len))
-    session_dequeue_notify (app_session);
+  return wrote;
+}
+
+static inline int
+picotls_ctx_write (tls_ctx_t *ctx, session_t *app_session,
+		   transport_send_params_t *sp)
+{
+  picotls_ctx_t *ptls_ctx = (picotls_ctx_t *) ctx;
+  u32 deq_max, deq_now, enq_max, enq_buf, wrote = 0;
+  svm_fifo_t *tcp_tx_fifo;
+  session_t *tcp_session;
 
-  if (to_tls_len)
-    tls_add_vpp_q_tx_evt (tls_session);
+  tcp_session = session_get_from_handle (ctx->tls_session_handle);
+  tcp_tx_fifo = tcp_session->tx_fifo;
 
-  if (from_app_len < deq_max || TLS_WRITE_IS_LEFT (ptls_ctx))
-    app_session->flags |= SESSION_F_CUSTOM_TX;
+  enq_max = svm_fifo_max_enqueue_prod (tcp_tx_fifo);
+  if (enq_max < 2048)
+    goto check_tls_fifo;
+
+  deq_max = svm_fifo_max_dequeue_cons (app_session->tx_fifo);
+  deq_max = clib_min (deq_max, enq_max);
+  if (!deq_max)
+    goto check_tls_fifo;
+
+  deq_now = clib_min (deq_max, sp->max_burst_size);
+  wrote = ptls_app_to_tcp_write (ptls_ctx, app_session, tcp_tx_fifo, deq_now);
+
+check_tls_fifo:
 
   if (ctx->app_closed)
     picotls_app_close (ctx);
 
-  return to_tls_len;
+  /* Deschedule and wait for deq notification if fifo is almost full */
+  enq_buf = clib_min (svm_fifo_size (tcp_tx_fifo) / 2, TLSP_MIN_ENQ_SPACE);
+  if (enq_max < wrote + enq_buf)
+    {
+      svm_fifo_add_want_deq_ntf (tcp_tx_fifo, SVM_FIFO_WANT_DEQ_NOTIF);
+      transport_connection_deschedule (&ctx->connection);
+      sp->flags |= TRANSPORT_SND_F_DESCHED;
+    }
+  else
+    /* Request tx reschedule of the app session */
+    app_session->flags |= SESSION_F_CUSTOM_TX;
+
+  return wrote;
 }
 
 static int
@@ -538,7 +617,6 @@ picotls_ctx_init_server (tls_ctx_t * ctx)
   ptls_ctx->rx_len = 0;
   ptls_ctx->rx_offset = 0;
 
-  ptls_ctx->write_buffer_offset = 0;
   return 0;
 }
 
@@ -562,7 +640,6 @@ picotls_ctx_init_client (tls_ctx_t *ctx)
 
   ptls_ctx->rx_len = 0;
   ptls_ctx->rx_offset = 0;
-  ptls_ctx->write_buffer_offset = 0;
 
   ptls_buffer_init (&hs_buf, "", 0);
   if (ptls_handshake (ptls_ctx->tls, &hs_buf, NULL, NULL, &hsprop) !=
@@ -629,6 +706,8 @@ tls_picotls_init (vlib_main_t * vm)
 
   vec_validate (pm->ctx_pool, num_threads - 1);
   vec_validate (pm->rx_bufs, num_threads - 1);
+  vec_validate (pm->tx_bufs, num_threads - 1);
+
   clib_rwlock_init (&picotls_main.crypto_keys_rw_lock);
 
   tls_register_engine (&picotls_engine, CRYPTO_ENGINE_PICOTLS);
diff --git a/src/plugins/tlspicotls/tls_picotls.h b/src/plugins/tlspicotls/tls_picotls.h
index e86b30aedfc..d24d7e2f172 100644
--- a/src/plugins/tlspicotls/tls_picotls.h
+++ b/src/plugins/tlspicotls/tls_picotls.h
@@ -16,9 +16,7 @@
 #define TLS_READ_IS_LEFT(x) ((x)->read_buffer.off != 0 && (x)->read_buffer.off != (x)->read_buffer_offset)
 #define TLS_READ_LEFT_LEN(x) ((x)->read_buffer.off - (x)->read_buffer_offset)
 
-#define TLS_WRITE_OFFSET(x) ((x)->write_buffer.base + (x)->write_buffer_offset)
-#define TLS_WRITE_IS_LEFT(x) ((x)->write_buffer.off != 0 && (x)->write_buffer.off != (x)->write_buffer_offset)
-
+#define TLSP_MIN_ENQ_SPACE (1 << 16)
 
 typedef struct tls_ctx_picotls_
 {
@@ -29,10 +27,7 @@ typedef struct tls_ctx_picotls_
   int rx_offset;
   int rx_len;
   ptls_buffer_t read_buffer;
-  ptls_buffer_t write_buffer;
-  uint8_t *write_content;
   int read_buffer_offset;
-  int write_buffer_offset;
 } picotls_ctx_t;
 
 typedef struct tls_listen_ctx_picotls_
@@ -44,8 +39,9 @@ typedef struct tls_listen_ctx_picotls_
 typedef struct picotls_main_
 {
   picotls_ctx_t ***ctx_pool;
-  u8 **rx_bufs;
   picotls_listen_ctx_t *lctx_pool;
+  u8 **tx_bufs;
+  u8 **rx_bufs;
   ptls_context_t *client_ptls_ctx;
   clib_rwlock_t crypto_keys_rw_lock;
 } picotls_main_t;