Update plugins_ioam.md

Source-Code-Analysis/plugins_ioam.md

@@ -1 +1,239 @@
 
+## iOAM
+
+### ipfixcollector
+
+**处理过程**
+
+```
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ipfix_collector_node) = {
+  .function = ipfix_collector_node_fn,
+  .name = "ipfix-collector",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ipfix_collector_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(ipfix_collector_error_strings),
+  .error_strings = ipfix_collector_error_strings,
+
+  .n_next_nodes = IPFIX_COLLECTOR_N_NEXT,
+
+  /* edit / add dispositions here */
+  .next_nodes = {
+    [IPFIX_COLLECTOR_NEXT_DROP] = "error-drop",
+  },
+};
+
+/**
+ * @brief Node to receive IP-Fix packets.
+ * @node ipfix-collector
+ *
+ * This function receives IP-FIX packets and forwards them to other graph nodes
+ * based on SetID field in IP-FIX.
+ *
+ * @param vm    vlib_main_t corresponding to the current thread.
+ * @param node  vlib_node_runtime_t data for this node.
+ * @param frame vlib_frame_t whose contents should be dispatched.
+ *
+ * @par Graph mechanics: buffer, next index usage
+ *
+ * <em>Uses:</em>
+ * - <code>vlib_buffer_get_current(p0)</code>
+ *     - Parses IP-Fix packet to extract SetId which will be used to decide
+ *       next node where packets should be enqueued.
+ *
+ * <em>Next Index:</em>
+ * - Dispatches the packet to other VPP graph nodes based on their registartion
+ *   for the IP-Fix SetId using API ipfix_collector_reg_setid().
+ */
+uword
+ipfix_collector_node_fn (vlib_main_t * vm,
+			 vlib_node_runtime_t * node,
+			 vlib_frame_t * from_frame)
+{
+  u32 n_left_from, next_index, *from, *to_next;
+  word n_no_listener = 0;
+  word n_listener = 0;
+
+  from = vlib_frame_vector_args (from_frame);
+  n_left_from = from_frame->n_vectors;
+
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  u32 bi0, bi1;
+	  vlib_buffer_t *b0, *b1;
+	  u32 next0, next1;
+	  ipfix_message_header_t *ipfix0, *ipfix1;
+	  ipfix_set_header_t *set0, *set1;
+	  u16 set_id0, set_id1;
+	  ipfix_client *client0, *client1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data,
+			   (sizeof (ipfix_message_header_t) +
+			    sizeof (ipfix_set_header_t)), LOAD);
+	    CLIB_PREFETCH (p3->data,
+			   (sizeof (ipfix_message_header_t) +
+			    sizeof (ipfix_set_header_t)), LOAD);
+	  }
+
+	  bi0 = from[0];
+	  bi1 = from[1];
+	  to_next[0] = bi0;
+	  to_next[1] = bi1;
+	  from += 2;
+	  to_next += 2;
+	  n_left_to_next -= 2;
+	  n_left_from -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+
+    /* ipfix消息头 */
+	  ipfix0 = vlib_buffer_get_current (b0);
+	  ipfix1 = vlib_buffer_get_current (b1);
+
+    /* ipfix set */
+	  set0 = (ipfix_set_header_t *) (ipfix0 + 1);
+	  set1 = (ipfix_set_header_t *) (ipfix1 + 1);
+
+    /* set id */
+	  set_id0 = (u16) (clib_net_to_host_u32 (set0->set_id_length) >> 16);
+	  set_id1 = (u16) (clib_net_to_host_u32 (set1->set_id_length) >> 16);
+
+    / ipfix client */
+	  client0 = ipfix_collector_get_client (set_id0);
+	  client1 = ipfix_collector_get_client (set_id1);
+
+	  if (PREDICT_TRUE (NULL != client0))
+	    {
+	      next0 = client0->client_next_node;
+	      n_listener++;
+	    }
+	  else
+	    {
+	      next0 = IPFIX_COLLECTOR_NEXT_DROP;
+	      n_no_listener++;
+	    }
+
+	  if (PREDICT_TRUE (NULL != client1))
+	    {
+	      next1 = client1->client_next_node;
+	      n_listener++;
+	    }
+	  else
+	    {
+	      next1 = IPFIX_COLLECTOR_NEXT_DROP;
+	      n_no_listener++;
+	    }
+    
+    /* 移动current data位置 */
+	  vlib_buffer_advance (b0,
+			       (sizeof (ipfix_message_header_t)
+				+ sizeof (ipfix_set_header_t)));
+	  vlib_buffer_advance (b1,
+			       (sizeof (ipfix_message_header_t)
+				+ sizeof (ipfix_set_header_t)));
+
+    /* trace */
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      ipfix_collector_trace_t *tr = vlib_add_trace (vm, node,
+							    b0, sizeof (*tr));
+	      tr->next_node = (client0 ? client0->client_node : 0xFFFFFFFF);
+	      tr->set_id = set_id0;
+	    }
+	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      ipfix_collector_trace_t *tr = vlib_add_trace (vm, node,
+							    b1, sizeof (*tr));
+	      tr->next_node = (client1 ? client1->client_node : 0xFFFFFFFF);
+	      tr->set_id = set_id1;
+	    }
+
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  ipfix_message_header_t *ipfix0;
+	  ipfix_set_header_t *set0;
+	  u16 set_id0;
+	  ipfix_client *client0;
+
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  ipfix0 = vlib_buffer_get_current (b0);
+
+	  set0 = (ipfix_set_header_t *) (ipfix0 + 1);
+
+	  set_id0 = (u16) (clib_net_to_host_u32 (set0->set_id_length) >> 16);
+
+	  client0 = ipfix_collector_get_client (set_id0);
+
+	  if (PREDICT_TRUE (NULL != client0))
+	    {
+	      next0 = client0->client_next_node;
+	      n_listener++;
+	    }
+	  else
+	    {
+	      next0 = IPFIX_COLLECTOR_NEXT_DROP;
+	      n_no_listener++;
+	    }
+
+	  vlib_buffer_advance (b0,
+			       (sizeof (ipfix_message_header_t)
+				+ sizeof (ipfix_set_header_t)));
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      ipfix_collector_trace_t *tr = vlib_add_trace (vm, node,
+							    b0, sizeof (*tr));
+	      tr->next_node = (client0 ? client0->client_node : 0xFFFFFFFF);
+	      tr->set_id = set_id0;
+	    }
+
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	}
+  
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+  vlib_error_count (vm, node->node_index,
+		    IPFIX_COLLECTOR_ERROR_NO_LISTENER, n_no_listener);
+  vlib_error_count (vm, node->node_index,
+		    IPFIX_COLLECTOR_ERROR_PROCESSED, n_listener);
+  return from_frame->n_vectors;
+}
+/* *INDENT-ON* */
+```