ioam: manycast using iOAM and SR (VPP-628)

Change-Id: I6d2afda991d771fb4a89fc3f6544f8e940a9b9f0
Signed-off-by: Shwetha Bhandari <shwethab@cisco.com>

1 files changed, 424 insertions, 0 deletions

diff --git a/src/plugins/ioam/ip6/ioam_cache_node.c b/src/plugins/ioam/ip6/ioam_cache_node.c
new file mode 100644
index 00000000000..6c8a038a4c1
--- /dev/null
+++ b/src/plugins/ioam/ip6/ioam_cache_node.c
@@ -0,0 +1,424 @@
+/*
+ * Copyright (c) 2017 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.
+ */
+/*
+ * This file implements caching of ioam header and reattaching
+ * it in response message by performing request-response matching.
+ *  Works for TCP SYN/SYN-ACK.
+ * This feature is used for anycast server selection.
+ * ioam data thus cached is used to measure and get complete round trip
+ * network path to help in server selection.
+ * There are 2 graph nodes defined to :
+ * 1. process packets that contain iOAM header and cache it
+ * 2. process TCP SYN-ACKs and reattach ioam header from the
+ *    cache corresponding to TCP-SYN
+ * These graph nodes are attached to the vnet graph based on
+ * ioam cache and classifier configs.
+ * e.g.
+ * If db06::06 is the anycast service IP6 address:
+ *
+ * set ioam ip6 cache
+ *
+ * Apply this classifier on interface where requests for anycast service are received:
+ * classify session acl-hit-next ip6-node ip6-lookup table-index 0 match l3 ip6 dst db06::06
+ *    ioam-decap anycast <<< ioam-decap is hooked to cache when set ioam ip6 cache is enabled
+ *
+ * Apply this classifier on interface where responses from anycast service are received:
+ * classify session acl-hit-next ip6-node ip6-add-from-cache-hop-by-hop table-index 0 match l3
+ *    ip6 src db06::06 ioam-encap anycast-response
+ *
+ */
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+#include <vnet/pg/pg.h>
+#include <vppinfra/error.h>
+#include <vnet/ip/ip.h>
+#include <ioam/ip6/ioam_cache.h>
+#include <vnet/ip/ip6_hop_by_hop.h>
+#include <vnet/ip/ip6_hop_by_hop_packet.h>
+
+typedef struct
+{
+  u32 next_index;
+  u32 flow_label;
+} cache_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_cache_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 *);
+  cache_trace_t *t = va_arg (*args, cache_trace_t *);
+
+  s = format (s, "CACHE: flow_label %d, next index %d",
+	      t->flow_label, t->next_index);
+  return s;
+}
+
+vlib_node_registration_t ioam_cache_node;
+
+#define foreach_cache_error \
+_(RECORDED, "ip6 iOAM headers cached")
+
+typedef enum
+{
+#define _(sym,str) CACHE_ERROR_##sym,
+  foreach_cache_error
+#undef _
+    CACHE_N_ERROR,
+} cache_error_t;
+
+static char *cache_error_strings[] = {
+#define _(sym,string) string,
+  foreach_cache_error
+#undef _
+};
+
+typedef enum
+{
+  IOAM_CACHE_NEXT_POP_HBYH,
+  IOAM_CACHE_N_NEXT,
+} cache_next_t;
+
+static uword
+ip6_ioam_cache_node_fn (vlib_main_t * vm,
+			vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+  u32 n_left_from, *from, *to_next;
+  cache_next_t next_index;
+  u32 recorded = 0;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_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);
+      // TODO: Dual loop
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *p0;
+	  u32 next0 = IOAM_CACHE_NEXT_POP_HBYH;
+	  ip6_header_t *ip0;
+	  ip6_hop_by_hop_header_t *hbh0;
+	  tcp_header_t *tcp0;
+	  u32 tcp_offset0;
+
+	  /* speculatively enqueue p0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  p0 = vlib_get_buffer (vm, bi0);
+	  ip0 = vlib_buffer_get_current (p0);
+	  if (IP_PROTOCOL_TCP ==
+	      ip6_locate_header (p0, ip0, IP_PROTOCOL_TCP, &tcp_offset0))
+	    {
+	      tcp0 = (tcp_header_t *) ((u8 *) ip0 + tcp_offset0);
+	      if ((tcp0->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
+		  (tcp0->flags & TCP_FLAG_ACK) == 0)
+		{
+		  /* Cache the ioam hbh header */
+		  hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
+		  if (0 == ioam_cache_add (p0,
+					   ip0,
+					   clib_net_to_host_u16
+					   (tcp0->src_port),
+					   clib_net_to_host_u16
+					   (tcp0->dst_port), hbh0,
+					   clib_net_to_host_u32
+					   (tcp0->seq_number) + 1))
+		    {
+		      recorded++;
+		    }
+		}
+	    }
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
+	    {
+	      if (p0->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  cache_trace_t *t =
+		    vlib_add_trace (vm, node, p0, sizeof (*t));
+		  t->flow_label =
+		    clib_net_to_host_u32
+		    (ip0->ip_version_traffic_class_and_flow_label);
+		  t->next_index = next0;
+		}
+	    }
+	  /* 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, ioam_cache_node.index,
+			       CACHE_ERROR_RECORDED, recorded);
+  return frame->n_vectors;
+}
+
+/*
+ * Node for IP6 iOAM header cache
+ */
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ioam_cache_node) =
+{
+  .function = ip6_ioam_cache_node_fn,
+  .name = "ip6-ioam-cache",
+  .vector_size = sizeof (u32),
+  .format_trace = format_cache_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (cache_error_strings),
+  .error_strings = cache_error_strings,
+  .n_next_nodes = IOAM_CACHE_N_NEXT,
+  /* edit / add dispositions here */
+  .next_nodes =
+  {
+    [IOAM_CACHE_NEXT_POP_HBYH] = "ip6-pop-hop-by-hop"
+  },
+};
+/* *INDENT-ON* */
+
+typedef struct
+{
+  u32 next_index;
+} ip6_add_from_cache_hbh_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_ip6_add_from_cache_hbh_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 *);
+  ip6_add_from_cache_hbh_trace_t *t = va_arg (*args,
+					      ip6_add_from_cache_hbh_trace_t
+					      *);
+
+  s = format (s, "IP6_ADD_FROM_CACHE_HBH: next index %d", t->next_index);
+  return s;
+}
+
+vlib_node_registration_t ip6_add_from_cache_hbh_node;
+
+#define foreach_ip6_add_from_cache_hbh_error \
+_(PROCESSED, "Pkts w/ added ip6 hop-by-hop options")
+
+typedef enum
+{
+#define _(sym,str) IP6_ADD_FROM_CACHE_HBH_ERROR_##sym,
+  foreach_ip6_add_from_cache_hbh_error
+#undef _
+    IP6_ADD_FROM_CACHE_HBH_N_ERROR,
+} ip6_add_from_cache_hbh_error_t;
+
+static char *ip6_add_from_cache_hbh_error_strings[] = {
+#define _(sym,string) string,
+  foreach_ip6_add_from_cache_hbh_error
+#undef _
+};
+
+#define foreach_ip6_ioam_cache_input_next        \
+  _(IP6_LOOKUP, "ip6-lookup")                   \
+  _(DROP, "error-drop")
+
+typedef enum
+{
+#define _(s,n) IP6_IOAM_CACHE_INPUT_NEXT_##s,
+  foreach_ip6_ioam_cache_input_next
+#undef _
+    IP6_IOAM_CACHE_INPUT_N_NEXT,
+} ip6_ioam_cache_input_next_t;
+
+
+static uword
+ip6_add_from_cache_hbh_node_fn (vlib_main_t * vm,
+				vlib_node_runtime_t * node,
+				vlib_frame_t * frame)
+{
+  ioam_cache_main_t *cm = &ioam_cache_main;
+  u32 n_left_from, *from, *to_next;
+  ip_lookup_next_t next_index;
+  u32 processed = 0;
+  u8 *rewrite = 0;
+  u32 rewrite_len = 0;
+  u32 sr_rewrite_len = vec_len (cm->sr_rewrite_template);
+
+  from = vlib_frame_vector_args (frame);
+  n_left_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);
+      // TODO: Dual loop
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0;
+	  ip6_header_t *ip0;
+	  ip6_hop_by_hop_header_t *hbh0;
+	  ip6_sr_header_t *srh0 = 0;
+	  u64 *copy_src0, *copy_dst0;
+	  u16 new_l0;
+	  tcp_header_t *tcp0;
+	  u32 tcp_offset0;
+	  ioam_cache_entry_t *entry = 0;
+
+	  next0 = IP6_IOAM_CACHE_INPUT_NEXT_IP6_LOOKUP;
+	  /* speculatively enqueue b0 to the current next frame */
+	  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);
+	  if (IP_PROTOCOL_TCP !=
+	      ip6_locate_header (b0, ip0, IP_PROTOCOL_TCP, &tcp_offset0))
+	    {
+	      goto TRACE0;
+	    }
+	  tcp0 = (tcp_header_t *) ((u8 *) ip0 + tcp_offset0);
+	  if (((tcp0->flags & TCP_FLAG_SYN) == TCP_FLAG_SYN &&
+	       (tcp0->flags & TCP_FLAG_ACK) == TCP_FLAG_ACK) ||
+	      (tcp0->flags & TCP_FLAG_RST) == TCP_FLAG_RST)
+	    {
+	      if (0 != (entry = ioam_cache_lookup (ip0,
+						   clib_net_to_host_u16
+						   (tcp0->src_port),
+						   clib_net_to_host_u16
+						   (tcp0->dst_port),
+						   clib_net_to_host_u32
+						   (tcp0->ack_number))))
+		{
+		  rewrite = entry->ioam_rewrite_string;
+		  rewrite_len = vec_len (rewrite);
+		}
+	      else
+		{
+		  next0 = IP6_IOAM_CACHE_INPUT_NEXT_DROP;
+		  goto TRACE0;
+		}
+	    }
+	  else
+	    goto TRACE0;
+
+
+	  /* Copy the ip header left by the required amount */
+	  copy_dst0 = (u64 *) (((u8 *) ip0) - (rewrite_len + sr_rewrite_len));
+	  copy_src0 = (u64 *) ip0;
+
+	  copy_dst0[0] = copy_src0[0];
+	  copy_dst0[1] = copy_src0[1];
+	  copy_dst0[2] = copy_src0[2];
+	  copy_dst0[3] = copy_src0[3];
+	  copy_dst0[4] = copy_src0[4];
+	  vlib_buffer_advance (b0, -(word) (rewrite_len + sr_rewrite_len));
+	  ip0 = vlib_buffer_get_current (b0);
+
+	  hbh0 = (ip6_hop_by_hop_header_t *) (ip0 + 1);
+	  srh0 = (ip6_sr_header_t *) ((u8 *) hbh0 + rewrite_len);
+	  /* $$$ tune, rewrite_len is a multiple of 8 */
+	  clib_memcpy (hbh0, rewrite, rewrite_len);
+	  clib_memcpy (srh0, cm->sr_rewrite_template, sr_rewrite_len);
+	  /* Copy dst address into the DA slot in the segment list */
+	  clib_memcpy (srh0->segments, ip0->dst_address.as_u64,
+		       sizeof (ip6_address_t));
+	  /* Rewrite the ip6 dst address with the first hop */
+	  clib_memcpy (ip0->dst_address.as_u64, entry->next_hop.as_u64,
+		       sizeof (ip6_address_t));
+	  clib_memcpy (&srh0->segments[1],
+		       (u8 *) hbh0 + entry->my_address_offset,
+		       sizeof (ip6_address_t));
+	  srh0->segments_left--;
+	  ioam_cache_entry_free (entry);
+
+	  /* Patch the protocol chain, insert the h-b-h (type 0) header */
+	  srh0->protocol = ip0->protocol;
+	  hbh0->protocol = IPPROTO_IPV6_ROUTE;
+	  ip0->protocol = 0;
+	  new_l0 =
+	    clib_net_to_host_u16 (ip0->payload_length) + rewrite_len +
+	    sr_rewrite_len;
+	  ip0->payload_length = clib_host_to_net_u16 (new_l0);
+	  processed++;
+	TRACE0:
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      ip6_add_from_cache_hbh_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->next_index = next0;
+	    }
+
+	  /* 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, ip6_add_from_cache_hbh_node.index,
+			       IP6_ADD_FROM_CACHE_HBH_ERROR_PROCESSED,
+			       processed);
+  return frame->n_vectors;
+}
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (ip6_add_from_cache_hbh_node) =
+{
+  .function = ip6_add_from_cache_hbh_node_fn,
+  .name = "ip6-add-from-cache-hop-by-hop",
+  .vector_size = sizeof (u32),
+  .format_trace = format_ip6_add_from_cache_hbh_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (ip6_add_from_cache_hbh_error_strings),
+  .error_strings =  ip6_add_from_cache_hbh_error_strings,
+  /* See ip/lookup.h */
+  .n_next_nodes = IP6_IOAM_CACHE_INPUT_N_NEXT,
+  .next_nodes =
+  {
+#define _(s,n) [IP6_IOAM_CACHE_INPUT_NEXT_##s] = n,
+    foreach_ip6_ioam_cache_input_next
+#undef _
+  },
+};
+/* *INDENT-ON* */
+
+VLIB_NODE_FUNCTION_MULTIARCH (ip6_add_from_cache_hbh_node,
+			      ip6_add_from_cache_hbh_node_fn)
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */