IP4 Router Alert option handling for IGMP

and a new ip4-options node, inserted between ip4-input and ip4-punt,
that checks for IP-router-alert option + IGMP combination and sends
the packet to the ip4-local. This is required because some IGMP
packets are sent to the group address and not the all-routers address.
All IGMP packets are sent with the router alert option.

Change-Id: I01f478d4d98ac9f806e0bcba0f6da6e4e7d26e2a
Signed-off-by: Neale Ranns <nranns@cisco.com>

5 files changed, 157 insertions, 14 deletions

diff --git a/src/vnet.am b/src/vnet.am
index 78eb481bc05..0a9cb5ffee4 100644
--- a/src/vnet.am
+++ b/src/vnet.am
@@ -354,6 +354,7 @@ libvnet_la_SOURCES +=				\
  vnet/ip/ip4_forward.c				\
  vnet/ip/ip4_punt_drop.c			\
  vnet/ip/ip4_input.c				\
+ vnet/ip/ip4_options.c				\
  vnet/ip/ip4_mtrie.c				\
  vnet/ip/ip4_pg.c				\
  vnet/ip/ip4_source_and_port_range_check.c	\
diff --git a/src/vnet/ip/ip4_input.c b/src/vnet/ip/ip4_input.c
index b476f95ab8b..1ecd43b7139 100644
--- a/src/vnet/ip/ip4_input.c
+++ b/src/vnet/ip/ip4_input.c
@@ -324,6 +324,7 @@ VLIB_REGISTER_NODE (ip4_input_node) = {
   .next_nodes = {
     [IP4_INPUT_NEXT_DROP] = "error-drop",
     [IP4_INPUT_NEXT_PUNT] = "error-punt",
+    [IP4_INPUT_NEXT_OPTIONS] = "ip4-options",
     [IP4_INPUT_NEXT_LOOKUP] = "ip4-lookup",
     [IP4_INPUT_NEXT_LOOKUP_MULTICAST] = "ip4-mfib-forward-lookup",
     [IP4_INPUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
@@ -342,6 +343,7 @@ VLIB_REGISTER_NODE (ip4_input_no_checksum_node) = {
   .next_nodes = {
     [IP4_INPUT_NEXT_DROP] = "error-drop",
     [IP4_INPUT_NEXT_PUNT] = "error-punt",
+    [IP4_INPUT_NEXT_OPTIONS] = "ip4-options",
     [IP4_INPUT_NEXT_LOOKUP] = "ip4-lookup",
     [IP4_INPUT_NEXT_LOOKUP_MULTICAST] = "ip4-mfib-forward-lookup",
     [IP4_INPUT_NEXT_ICMP_ERROR] = "ip4-icmp-error",
diff --git a/src/vnet/ip/ip4_input.h b/src/vnet/ip/ip4_input.h
index 889b423d700..880896e6430 100644
--- a/src/vnet/ip/ip4_input.h
+++ b/src/vnet/ip/ip4_input.h
@@ -49,6 +49,7 @@ typedef enum
 {
   IP4_INPUT_NEXT_DROP,
   IP4_INPUT_NEXT_PUNT,
+  IP4_INPUT_NEXT_OPTIONS,
   IP4_INPUT_NEXT_LOOKUP,
   IP4_INPUT_NEXT_LOOKUP_MULTICAST,
   IP4_INPUT_NEXT_ICMP_ERROR,
@@ -153,7 +154,7 @@ ip4_input_check_x4 (vlib_main_t * vm,
 	}
       else
 	next[0] = error0 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p[0]->error = error_node->errors[error0];
     }
   if (PREDICT_FALSE (error1 != IP4_ERROR_NONE))
@@ -167,7 +168,7 @@ ip4_input_check_x4 (vlib_main_t * vm,
 	}
       else
 	next[1] = error1 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p[1]->error = error_node->errors[error1];
     }
   if (PREDICT_FALSE (error2 != IP4_ERROR_NONE))
@@ -181,7 +182,7 @@ ip4_input_check_x4 (vlib_main_t * vm,
 	}
       else
 	next[2] = error2 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p[2]->error = error_node->errors[error2];
     }
   if (PREDICT_FALSE (error3 != IP4_ERROR_NONE))
@@ -195,7 +196,7 @@ ip4_input_check_x4 (vlib_main_t * vm,
 	}
       else
 	next[3] = error3 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p[3]->error = error_node->errors[error3];
     }
 }
@@ -256,7 +257,7 @@ ip4_input_check_x2 (vlib_main_t * vm,
 	}
       else
 	*next0 = error0 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p0->error = error_node->errors[error0];
     }
   if (PREDICT_FALSE (error1 != IP4_ERROR_NONE))
@@ -270,10 +271,9 @@ ip4_input_check_x2 (vlib_main_t * vm,
 	}
       else
 	*next1 = error1 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p1->error = error_node->errors[error1];
     }
-
 }
 
 always_inline void
@@ -290,11 +290,6 @@ ip4_input_check_x1 (vlib_main_t * vm,
 
   check_ver_opt_csum (ip0, &error0, verify_checksum);
 
-  /* Punt packets with options or wrong version. */
-  if (PREDICT_FALSE (ip0->ip_version_and_header_length != 0x45))
-    error0 = (ip0->ip_version_and_header_length & 0xf) != 5 ?
-      IP4_ERROR_OPTIONS : IP4_ERROR_VERSION;
-
   /* Drop fragmentation offset 1 packets. */
   error0 = ip4_get_fragment_offset (ip0) == 1 ?
     IP4_ERROR_FRAGMENT_OFFSET_ONE : error0;
@@ -322,10 +317,9 @@ ip4_input_check_x1 (vlib_main_t * vm,
 	}
       else
 	*next0 = error0 != IP4_ERROR_OPTIONS ?
-	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_PUNT;
+	  IP4_INPUT_NEXT_DROP : IP4_INPUT_NEXT_OPTIONS;
       p0->error = error_node->errors[error0];
     }
-
 }
 
 /*
diff --git a/src/vnet/ip/ip4_options.c b/src/vnet/ip/ip4_options.c
new file mode 100644
index 00000000000..c008b9bde8c
--- /dev/null
+++ b/src/vnet/ip/ip4_options.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (c) 2018 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.
+ */
+
+/**
+ * @brief Handle IPv4 header options in the data-path
+ */
+
+#include <vnet/ip/ip.h>
+
+typedef enum ip4_options_next_t_
+{
+  IP4_OPTIONS_NEXT_PUNT,
+  IP4_OPTIONS_NEXT_LOCAL,
+  IP4_OPTIONS_N_NEXT,
+} ip4_options_next_t;
+
+typedef struct ip4_options_trace_t_
+{
+  u8 option[4];
+} ip4_options_trace_t;
+
+VLIB_NODE_FN (ip4_options_node) (vlib_main_t * vm,
+				 vlib_node_runtime_t * node,
+				 vlib_frame_t * frame)
+{
+  uword n_left_from, n_left_to_next, next_index;
+  u32 *from, *to_next;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = 0;
+
+  while (n_left_from > 0)
+    {
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+      /*
+       * IP options packets, when properly used, are very low rate,
+       * so this code is not dual-looped for extra performance.
+       */
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  ip4_options_next_t next;
+	  ip4_header_t *ip4;
+	  vlib_buffer_t *b;
+	  u8 *options;
+	  u32 bi;
+
+	  bi = from[0];
+	  from += 1;
+	  n_left_from -= 1;
+	  to_next[0] = bi;
+	  to_next += 1;
+	  n_left_to_next -= 1;
+
+	  b = vlib_get_buffer (vm, bi);
+	  ip4 = vlib_buffer_get_current (b);
+	  next = IP4_OPTIONS_NEXT_PUNT;
+
+	  options = (u8 *) (ip4 + 1);
+
+	  /*
+	   * mask out the copy flag to leave the option type
+	   */
+	  switch (options[0] & 0x7f)
+	    {
+	    case IP4_ROUTER_ALERT_OPTION:
+	      /*
+	       * if it's an IGMP packet, pass up the local stack
+	       */
+	      if (IP_PROTOCOL_IGMP == ip4->protocol)
+		{
+		  next = IP4_OPTIONS_NEXT_LOCAL;
+		}
+	      break;
+	    default:
+	      break;
+	    }
+
+	  if (b->flags & VLIB_BUFFER_IS_TRACED)
+	    {
+	      ip4_options_trace_t *t =
+		vlib_add_trace (vm, node, b, sizeof (*t));
+
+	      clib_memcpy (t->option, options, 4);
+	    }
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
+					   n_left_to_next, bi, next);
+
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+  return frame->n_vectors;
+}
+
+u8 *
+format_ip4_options_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 *);
+  ip4_options_trace_t *t = va_arg (*args, ip4_options_trace_t *);
+  u32 indent = format_get_indent (s);
+
+  s = format (s, "%Uoption:[0x%x,0x%x,0x%x,0x%x]",
+	      format_white_space, indent,
+	      t->option[0], t->option[1], t->option[2], t->option[3]);
+  return s;
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip4_options_node) = {
+  .name = "ip4-options",
+  .vector_size = sizeof (u32),
+
+  .n_next_nodes = IP4_OPTIONS_N_NEXT,
+  .next_nodes = {
+    [IP4_OPTIONS_NEXT_PUNT] = "ip4-punt",
+    [IP4_OPTIONS_NEXT_LOCAL] = "ip4-local",
+  },
+  .format_buffer = format_ip4_header,
+  .format_trace = format_ip4_options_trace,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/ip/ip4_packet.h b/src/vnet/ip/ip4_packet.h
index 2f0c75e4924..c41a8021d96 100644
--- a/src/vnet/ip/ip4_packet.h
+++ b/src/vnet/ip/ip4_packet.h
@@ -193,6 +193,8 @@ typedef union
 #define IP4_VERSION_AND_HEADER_LENGTH_NO_OPTIONS \
   ((4 << 4) | (sizeof (ip4_header_t) / sizeof (u32)))
 
+#define IP4_ROUTER_ALERT_OPTION 20
+
 always_inline int
 ip4_get_fragment_offset (ip4_header_t * i)
 {