Add worker-handoff node

worker-handoff node is universal node which taakes packets
from the input node and hands them over to worker threads.
Currently it supports flow hashing based on ipv4, ipv6 and
mpls headers.

New cli:

set interface handoff <intrerface-name> workers <list>

e.g.

set interface handoff TenGigabitEthernet2/0/0 workers 3-6,9-10

Change-Id: Iaf0df83e69bb0e84969865e0e1cdb000b0864cf5
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/vnet/vnet/handoff.h b/vnet/vnet/handoff.h
new file mode 100644
index 0000000..e0938eb
--- /dev/null
+++ b/vnet/vnet/handoff.h
@@ -0,0 +1,228 @@
+/*
+ * Copyright (c) 2016 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.
+ */
+
+#ifndef included_vnet_handoff_h
+#define included_vnet_handoff_h
+
+#include <vlib/vlib.h>
+#include <vnet/ethernet/ethernet.h>
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+#include <vnet/mpls-gre/packet.h>
+
+typedef enum {
+  HANDOFF_DISPATCH_NEXT_IP4_INPUT,
+  HANDOFF_DISPATCH_NEXT_IP6_INPUT,
+  HANDOFF_DISPATCH_NEXT_MPLS_INPUT,
+  HANDOFF_DISPATCH_NEXT_ETHERNET_INPUT,
+  HANDOFF_DISPATCH_NEXT_DROP,
+  HANDOFF_DISPATCH_N_NEXT,
+} handoff_dispatch_next_t;
+
+static inline
+void vlib_put_handoff_queue_elt (vlib_frame_queue_elt_t * hf)
+{
+  CLIB_MEMORY_BARRIER();
+  hf->valid = 1;
+}
+
+static inline vlib_frame_queue_elt_t *
+vlib_get_handoff_queue_elt (u32 vlib_worker_index)
+{
+  vlib_frame_queue_t *fq;
+  vlib_frame_queue_elt_t *elt;
+  u64 new_tail;
+
+  fq = vlib_frame_queues[vlib_worker_index];
+  ASSERT (fq);
+
+  new_tail = __sync_add_and_fetch (&fq->tail, 1);
+
+  /* Wait until a ring slot is available */
+  while (new_tail >= fq->head_hint + fq->nelts)
+      vlib_worker_thread_barrier_check ();
+
+  elt = fq->elts + (new_tail & (fq->nelts-1));
+
+  /* this would be very bad... */
+  while (elt->valid)
+    ;
+
+  elt->msg_type = VLIB_FRAME_QUEUE_ELT_DISPATCH_FRAME;
+  elt->last_n_vectors = elt->n_vectors = 0;
+
+  return elt;
+}
+
+static inline vlib_frame_queue_t *
+is_vlib_handoff_queue_congested (
+    u32 vlib_worker_index,
+    u32 queue_hi_thresh,
+    vlib_frame_queue_t ** handoff_queue_by_worker_index)
+{
+  vlib_frame_queue_t *fq;
+
+  fq = handoff_queue_by_worker_index [vlib_worker_index];
+  if (fq != (vlib_frame_queue_t *)(~0))
+      return fq;
+
+  fq = vlib_frame_queues[vlib_worker_index];
+  ASSERT (fq);
+
+  if (PREDICT_FALSE(fq->tail >= (fq->head_hint + queue_hi_thresh))) {
+    /* a valid entry in the array will indicate the queue has reached
+     * the specified threshold and is congested
+     */
+    handoff_queue_by_worker_index [vlib_worker_index] = fq;
+    fq->enqueue_full_events++;
+    return fq;
+  }
+
+  return NULL;
+}
+
+static inline vlib_frame_queue_elt_t *
+dpdk_get_handoff_queue_elt (u32 vlib_worker_index,
+			    vlib_frame_queue_elt_t **
+			      handoff_queue_elt_by_worker_index)
+{
+  vlib_frame_queue_elt_t *elt;
+
+  if (handoff_queue_elt_by_worker_index [vlib_worker_index])
+      return handoff_queue_elt_by_worker_index [vlib_worker_index];
+
+  elt = vlib_get_handoff_queue_elt (vlib_worker_index);
+
+  handoff_queue_elt_by_worker_index [vlib_worker_index] = elt;
+
+  return elt;
+}
+
+static inline u64 ipv4_get_key (ip4_header_t *ip)
+{
+   u64  hash_key;
+
+   hash_key = *((u64*)(&ip->address_pair)) ^ ip->protocol;
+
+   return hash_key;
+}
+
+static inline u64 ipv6_get_key (ip6_header_t *ip)
+{
+   u64  hash_key;
+
+   hash_key = ip->src_address.as_u64[0] ^
+              rotate_left(ip->src_address.as_u64[1],13) ^
+              rotate_left(ip->dst_address.as_u64[0],26) ^
+              rotate_left(ip->dst_address.as_u64[1],39) ^
+              ip->protocol;
+
+   return hash_key;
+}
+
+#define MPLS_BOTTOM_OF_STACK_BIT_MASK   0x00000100U
+#define MPLS_LABEL_MASK                 0xFFFFF000U
+
+static inline u64 mpls_get_key (mpls_unicast_header_t *m)
+{
+   u64                     hash_key;
+   u8                      ip_ver;
+
+
+   /* find the bottom of the MPLS label stack. */
+   if (PREDICT_TRUE(m->label_exp_s_ttl &
+                    clib_net_to_host_u32(MPLS_BOTTOM_OF_STACK_BIT_MASK))) {
+       goto bottom_lbl_found;
+   }
+   m++;
+
+   if (PREDICT_TRUE(m->label_exp_s_ttl &
+                    clib_net_to_host_u32(MPLS_BOTTOM_OF_STACK_BIT_MASK))) {
+       goto bottom_lbl_found;
+   }
+   m++;
+
+   if (m->label_exp_s_ttl & clib_net_to_host_u32(MPLS_BOTTOM_OF_STACK_BIT_MASK)) {
+       goto bottom_lbl_found;
+   }
+   m++;
+
+   if (m->label_exp_s_ttl & clib_net_to_host_u32(MPLS_BOTTOM_OF_STACK_BIT_MASK)) {
+       goto bottom_lbl_found;
+   }
+   m++;
+
+   if (m->label_exp_s_ttl & clib_net_to_host_u32(MPLS_BOTTOM_OF_STACK_BIT_MASK)) {
+       goto bottom_lbl_found;
+   }
+
+   /* the bottom label was not found - use the last label */
+   hash_key = m->label_exp_s_ttl & clib_net_to_host_u32(MPLS_LABEL_MASK);
+
+   return hash_key;
+
+bottom_lbl_found:
+   m++;
+   ip_ver = (*((u8 *)m) >> 4);
+
+   /* find out if it is IPV4 or IPV6 header */
+   if (PREDICT_TRUE(ip_ver == 4)) {
+       hash_key = ipv4_get_key((ip4_header_t *)m);
+   } else if (PREDICT_TRUE(ip_ver == 6)) {
+       hash_key = ipv6_get_key((ip6_header_t *)m);
+   } else {
+       /* use the bottom label */
+       hash_key = (m-1)->label_exp_s_ttl & clib_net_to_host_u32(MPLS_LABEL_MASK);
+   }
+
+   return hash_key;
+
+}
+
+
+static inline u64
+eth_get_key (ethernet_header_t *h0)
+{
+   u64 hash_key;
+
+   if (PREDICT_TRUE(h0->type) == clib_host_to_net_u16(ETHERNET_TYPE_IP4)) {
+       hash_key = ipv4_get_key((ip4_header_t *)(h0+1));
+   } else if (h0->type == clib_host_to_net_u16(ETHERNET_TYPE_IP6)) {
+       hash_key = ipv6_get_key((ip6_header_t *)(h0+1));
+   } else if (h0->type == clib_host_to_net_u16(ETHERNET_TYPE_MPLS_UNICAST)) {
+       hash_key = mpls_get_key((mpls_unicast_header_t *)(h0+1));
+   } else if ((h0->type == clib_host_to_net_u16(ETHERNET_TYPE_VLAN)) ||
+              (h0->type == clib_host_to_net_u16(ETHERNET_TYPE_DOT1AD))) {
+       ethernet_vlan_header_t * outer = (ethernet_vlan_header_t *)(h0 + 1);
+
+       outer = (outer->type == clib_host_to_net_u16(ETHERNET_TYPE_VLAN)) ?
+                                  outer+1 : outer;
+       if (PREDICT_TRUE(outer->type) == clib_host_to_net_u16(ETHERNET_TYPE_IP4)) {
+           hash_key = ipv4_get_key((ip4_header_t *)(outer+1));
+       } else if (outer->type == clib_host_to_net_u16 (ETHERNET_TYPE_IP6)) {
+           hash_key = ipv6_get_key((ip6_header_t *)(outer+1));
+       } else if (outer->type == clib_host_to_net_u16(ETHERNET_TYPE_MPLS_UNICAST)) {
+           hash_key = mpls_get_key((mpls_unicast_header_t *)(outer+1));
+       }  else {
+           hash_key = outer->type;
+       }
+   } else {
+       hash_key  = 0;
+   }
+
+   return hash_key;
+}
+
+#endif /* included_vnet_handoff_h */