memif: Process bad descriptors correctly in memif_process_desc

[vpp.git] / src / plugins / memif / node.c

diff --git a/src/plugins/memif/node.c b/src/plugins/memif/node.c
index 1f636f2..2d7b71f 100644 (file)
--- a/src/plugins/memif/node.c
+++ b/src/plugins/memif/node.c
@@ -223,9 +223,9 @@ memif_validate_desc_data (memif_per_thread_data_t *ptd, memif_if_t *mif,
          desc_data[i] = r->shm + offset;
          if (len > max_len)
            max_len = len;
-         xor_status |= desc_status[i].as_u8;
          n_rx_bytes += len;
        }
+      xor_status |= desc_status[i].as_u8;
     }
 
   ptd->max_desc_len = max_len;
@@ -247,7 +247,8 @@ memif_process_desc (vlib_main_t *vm, vlib_node_runtime_t *node,
   u32 n_buffers = 0;
   u32 n_left = ptd->n_packets;
   u32 packet_len;
-  int i = 0;
+  int i = -1;
+  int bad_packets = 0;
 
   /* construct copy and packet vector out of ring slots */
   while (n_left)
@@ -261,13 +262,21 @@ memif_process_desc (vlib_main_t *vm, vlib_node_runtime_t *node,
       dst_off = start_offset;
 
     next_slot:
+      i++; /* next descriptor */
       n_bytes_left = desc_len[i];
 
       packet_len += n_bytes_left;
       mb0 = desc_data[i];
 
       if (PREDICT_FALSE (desc_status[i].err))
-       vlib_error_count (vm, node->node_index, MEMIF_INPUT_ERROR_BAD_DESC, 1);
+       {
+         vlib_error_count (vm, node->node_index, MEMIF_INPUT_ERROR_BAD_DESC,
+                           1);
+         bad_packets++;
+         ASSERT (n_buffers > 0);
+         n_buffers--;
+         goto next_packet;
+       }
       else
        do
          {
@@ -287,9 +296,6 @@ memif_process_desc (vlib_main_t *vm, vlib_node_runtime_t *node,
          }
        while (PREDICT_FALSE (n_bytes_left));
 
-      /* next descriptor */
-      i++;
-
       if (desc_status[i].next)
        {
          src_off = 0;
@@ -300,9 +306,12 @@ memif_process_desc (vlib_main_t *vm, vlib_node_runtime_t *node,
       po->packet_len = packet_len;
       po++;
 
+    next_packet:
       /* next packet */
       n_left--;
     }
+  ASSERT (ptd->n_packets >= bad_packets);
+  ptd->n_packets -= bad_packets;
   return n_buffers;
 }
 static_always_inline void
@@ -464,6 +473,21 @@ memif_fill_buffer_mdata (vlib_main_t *vm, vlib_node_runtime_t *node,
     }
 }
 
+static_always_inline void
+memif_advance_ring (memif_ring_type_t type, memif_queue_t *mq,
+                   memif_ring_t *ring, u16 cur_slot)
+{
+  if (type == MEMIF_RING_S2M)
+    {
+      __atomic_store_n (&ring->tail, cur_slot, __ATOMIC_RELEASE);
+      mq->last_head = cur_slot;
+    }
+  else
+    {
+      mq->last_tail = cur_slot;
+    }
+}
+
 static_always_inline uword
 memif_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
                           memif_if_t *mif, memif_ring_type_t type, u16 qid,
@@ -535,6 +559,13 @@ memif_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
   else
     n_buffers = memif_process_desc (vm, node, ptd, mif);
 
+  if (PREDICT_FALSE (n_buffers == 0))
+    {
+      /* All descriptors are bad. Release slots in the ring and bail */
+      memif_advance_ring (type, mq, ring, cur_slot);
+      goto refill;
+    }
+
   /* allocate free buffers */
   vec_validate_aligned (ptd->buffers, n_buffers - 1, CLIB_CACHE_LINE_BYTES);
   n_alloc = vlib_buffer_alloc_from_pool (vm, ptd->buffers, n_buffers,
@@ -557,7 +588,7 @@ memif_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 
       vlib_get_buffers (vm, ptd->buffers, buffer_ptrs, n_buffers);
 
-      for (i = 0; i < n_pkts - 8; i++)
+      for (i = 0; i + 8 < n_pkts; i++)
        {
          clib_prefetch_load (desc_data[i + 8]);
          clib_prefetch_store (buffer_ptrs[i + 8]->data);
@@ -574,7 +605,7 @@ memif_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
       u32 n_pkts = vec_len (ptd->copy_ops);
       co = ptd->copy_ops;
 
-      for (i = 0; i < n_pkts - 8; i++)
+      for (i = 0; i + 8 < n_pkts; i++)
        {
          clib_prefetch_load (co[i + 8].data);
          b = vlib_get_buffer (vm, ptd->buffers[co[i].buffer_vec_index]);
@@ -590,15 +621,7 @@ memif_device_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
     }
 
   /* release slots from the ring */
-  if (type == MEMIF_RING_S2M)
-    {
-      __atomic_store_n (&ring->tail, cur_slot, __ATOMIC_RELEASE);
-      mq->last_head = cur_slot;
-    }
-  else
-    {
-      mq->last_tail = cur_slot;
-    }
+  memif_advance_ring (type, mq, ring, cur_slot);
 
   /* prepare buffer template and next indices */
   vnet_buffer (&ptd->buffer_template)->sw_if_index[VLIB_RX] = mif->sw_if_index;