1 files changed, 324 insertions, 0 deletions

diff --git a/src/plugins/dhcp/dhcp_client_detect.c b/src/plugins/dhcp/dhcp_client_detect.c
new file mode 100644
index 00000000000..31b89850802
--- /dev/null
+++ b/src/plugins/dhcp/dhcp_client_detect.c
@@ -0,0 +1,324 @@
+/*
+ * DHCP feature; applied as an input feature to select DHCP packets
+ *
+ * Copyright (c) 2013 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 <dhcp/client.h>
+#include <vnet/udp/udp.h>
+
+#define foreach_dhcp_client_detect                    \
+  _(EXTRACT, "Extract")
+
+typedef enum
+{
+#define _(sym,str) DHCP_CLIENT_DETECT_ERROR_##sym,
+  foreach_dhcp_client_detect
+#undef _
+    DHCP_CLIENT_DETECT_N_ERROR,
+} dhcp_client_detect_error_t;
+
+static char *dhcp_client_detect_error_strings[] = {
+#define _(sym,string) string,
+  foreach_dhcp_client_detect
+#undef _
+};
+
+typedef enum
+{
+#define _(sym,str) DHCP_CLIENT_DETECT_NEXT_##sym,
+  foreach_dhcp_client_detect
+#undef _
+    DHCP_CLIENT_DETECT_N_NEXT,
+} dhcp_client_detect_next_t;
+
+/**
+ * per-packet trace data
+ */
+typedef struct dhcp_client_detect_trace_t_
+{
+  /* per-pkt trace data */
+  u8 extracted;
+} dhcp_client_detect_trace_t;
+
+VLIB_NODE_FN (dhcp_client_detect_node) (vlib_main_t * vm,
+					vlib_node_runtime_t * node,
+					vlib_frame_t * frame)
+{
+  dhcp_client_detect_next_t next_index;
+  u16 dhcp_client_port_network_order;
+  u32 n_left_from, *from, *to_next;
+  u32 extractions;
+
+  dhcp_client_port_network_order =
+    clib_net_to_host_u16 (UDP_DST_PORT_dhcp_to_client);
+  next_index = 0;
+  extractions = 0;
+  n_left_from = frame->n_vectors;
+  from = vlib_frame_vector_args (frame);
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      /*
+       * This loop is optimised not so we can really quickly process DHCp
+       * offers... but so we can quickly sift them out when the interface
+       * is also receiving 'normal' packets
+       */
+      while (n_left_from >= 8 && n_left_to_next >= 4)
+	{
+	  udp_header_t *udp0, *udp1, *udp2, *udp3;
+	  ip4_header_t *ip0, *ip1, *ip2, *ip3;
+	  vlib_buffer_t *b0, *b1, *b2, *b3;
+	  u32 next0, next1, next2, next3;
+	  u32 bi0, bi1, bi2, bi3;
+
+	  next0 = next1 = next2 = next3 = ~0;
+	  bi0 = to_next[0] = from[0];
+	  bi1 = to_next[1] = from[1];
+	  bi2 = to_next[2] = from[2];
+	  bi3 = to_next[3] = from[3];
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3, *p4, *p5;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+	    p4 = vlib_get_buffer (vm, from[4]);
+	    p5 = vlib_get_buffer (vm, from[5]);
+
+	    vlib_prefetch_buffer_header (p2, STORE);
+	    vlib_prefetch_buffer_header (p3, STORE);
+	    vlib_prefetch_buffer_header (p4, STORE);
+	    vlib_prefetch_buffer_header (p5, STORE);
+
+	    CLIB_PREFETCH (p2->data, sizeof (ip0[0]) + sizeof (udp0[0]),
+			   STORE);
+	    CLIB_PREFETCH (p3->data, sizeof (ip0[0]) + sizeof (udp0[0]),
+			   STORE);
+	    CLIB_PREFETCH (p4->data, sizeof (ip0[0]) + sizeof (udp0[0]),
+			   STORE);
+	    CLIB_PREFETCH (p5->data, sizeof (ip0[0]) + sizeof (udp0[0]),
+			   STORE);
+	  }
+
+	  from += 4;
+	  to_next += 4;
+	  n_left_from -= 4;
+	  n_left_to_next -= 4;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+	  b2 = vlib_get_buffer (vm, bi2);
+	  b3 = vlib_get_buffer (vm, bi3);
+	  ip0 = vlib_buffer_get_current (b0);
+	  ip1 = vlib_buffer_get_current (b1);
+	  ip2 = vlib_buffer_get_current (b2);
+	  ip3 = vlib_buffer_get_current (b2);
+
+	  vnet_feature_next (&next0, b0);
+	  vnet_feature_next (&next1, b1);
+	  vnet_feature_next (&next2, b2);
+	  vnet_feature_next (&next3, b3);
+
+	  if (ip0->protocol == IP_PROTOCOL_UDP)
+	    {
+	      udp0 = (udp_header_t *) (ip0 + 1);
+
+	      if (dhcp_client_port_network_order == udp0->dst_port)
+		{
+		  next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
+		  extractions++;
+		}
+	    }
+	  if (ip1->protocol == IP_PROTOCOL_UDP)
+	    {
+	      udp1 = (udp_header_t *) (ip1 + 1);
+
+	      if (dhcp_client_port_network_order == udp1->dst_port)
+		{
+		  next1 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
+		  extractions++;
+		}
+	    }
+	  if (ip2->protocol == IP_PROTOCOL_UDP)
+	    {
+	      udp2 = (udp_header_t *) (ip2 + 1);
+
+	      if (dhcp_client_port_network_order == udp2->dst_port)
+		{
+		  next2 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
+		  extractions++;
+		}
+	    }
+	  if (ip3->protocol == IP_PROTOCOL_UDP)
+	    {
+	      udp3 = (udp_header_t *) (ip3 + 1);
+
+	      if (dhcp_client_port_network_order == udp3->dst_port)
+		{
+		  next3 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
+		  extractions++;
+		}
+	    }
+
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      dhcp_client_detect_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
+	    }
+	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      dhcp_client_detect_trace_t *t =
+		vlib_add_trace (vm, node, b1, sizeof (*t));
+	      t->extracted = (next1 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
+	    }
+	  if (PREDICT_FALSE (b2->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      dhcp_client_detect_trace_t *t =
+		vlib_add_trace (vm, node, b2, sizeof (*t));
+	      t->extracted = (next2 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
+	    }
+	  if (PREDICT_FALSE (b3->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      dhcp_client_detect_trace_t *t =
+		vlib_add_trace (vm, node, b3, sizeof (*t));
+	      t->extracted = (next3 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
+	    }
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, bi2, bi3,
+					   next0, next1, next2, next3);
+	}
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  udp_header_t *udp0;
+	  vlib_buffer_t *b0;
+	  ip4_header_t *ip0;
+	  u32 next0 = ~0;
+	  u32 bi0;
+
+	  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);
+	  ip0 = vlib_buffer_get_current (b0);
+
+	  /*
+	   * when this feature is applied on an interface that is already
+	   * accepting packets (because e.g. the interface has other addresses
+	   * assigned) we are looking for the preverbial needle in the haystack
+	   * so assume the packet is not the one we are looking for.
+	   */
+	  vnet_feature_next (&next0, b0);
+
+	  /*
+	   * all we are looking for here is DHCP/BOOTP packet-to-client
+	   * UDO port.
+	   */
+	  if (ip0->protocol == IP_PROTOCOL_UDP)
+	    {
+	      udp0 = (udp_header_t *) (ip0 + 1);
+
+	      if (dhcp_client_port_network_order == udp0->dst_port)
+		{
+		  next0 = DHCP_CLIENT_DETECT_NEXT_EXTRACT;
+		  extractions++;
+		}
+	    }
+
+	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
+	    {
+	      dhcp_client_detect_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->extracted = (next0 == DHCP_CLIENT_DETECT_NEXT_EXTRACT);
+	    }
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  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_node_increment_counter (vm, node->node_index,
+			       DHCP_CLIENT_DETECT_ERROR_EXTRACT, extractions);
+
+  return frame->n_vectors;
+}
+
+/* packet trace format function */
+static u8 *
+format_dhcp_client_detect_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  dhcp_client_detect_trace_t *t =
+    va_arg (*args, dhcp_client_detect_trace_t *);
+
+  s = format (s, "dhcp-client-detect: %s", (t->extracted ? "yes" : "no"));
+
+  return s;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dhcp_client_detect_node) = {
+  .name = "ip4-dhcp-client-detect",
+  .vector_size = sizeof (u32),
+  .format_trace = format_dhcp_client_detect_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+
+  .n_errors = ARRAY_LEN(dhcp_client_detect_error_strings),
+  .error_strings = dhcp_client_detect_error_strings,
+
+  .n_next_nodes = DHCP_CLIENT_DETECT_N_NEXT,
+  .next_nodes = {
+    /*
+     * Jump straight to the UDP dispatch node thus avoiding
+     * the RPF checks in ip4-local that will fail
+     */
+    [DHCP_CLIENT_DETECT_NEXT_EXTRACT] = "ip4-udp-lookup",
+  },
+};
+
+VNET_FEATURE_INIT (ip4_dvr_reinject_feat_node, static) =
+{
+  .arc_name = "ip4-unicast",
+  .node_name = "ip4-dhcp-client-detect",
+  .runs_before = VNET_FEATURES ("ip4-not-enabled"),
+};
+
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */