VPP-130: MagLev-like Load Balancer

This plugin provides load balancing for VPP in a way that is largely inspired
from Google's MagLev: http://research.google.com/pubs/pub44824.html

More info in the README.md

Change-Id: I1223f495d5c2d5200808a398504119f2830337e9
Signed-off-by: Pierre Pfister <ppfister@cisco.com>

1 files changed, 746 insertions, 0 deletions

diff --git a/plugins/lb-plugin/lb/lb.c b/plugins/lb-plugin/lb/lb.c
new file mode 100644
index 00000000000..5eeeac5cfb7
--- /dev/null
+++ b/plugins/lb-plugin/lb/lb.c
@@ -0,0 +1,746 @@
+/*
+ * 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.
+ */
+
+#include <lb/lb.h>
+#include <vnet/plugin/plugin.h>
+#include <vnet/api_errno.h>
+
+//GC runs at most once every so many seconds
+#define LB_GARBAGE_RUN 60
+
+//After so many seconds. It is assumed that inter-core race condition will not occur.
+#define LB_CONCURRENCY_TIMEOUT 10
+
+lb_main_t lb_main;
+
+#define lb_get_writer_lock() do {} while(__sync_lock_test_and_set (lb_main.writer_lock, 1))
+#define lb_put_writer_lock() lb_main.writer_lock[0] = 0
+
+u32 lb_hash_time_now(vlib_main_t * vm)
+{
+  return (u32) (vlib_time_now(vm) + 10000);
+}
+
+u8 *format_lb_main (u8 * s, va_list * args)
+{
+  vlib_thread_main_t *tm = vlib_get_thread_main();
+  lb_main_t *lbm = &lb_main;
+  s = format(s, "lb_main");
+  s = format(s, " ip4-src-address: %U \n", format_ip4_address, &lbm->ip4_src_address);
+  s = format(s, " ip6-src-address: %U \n", format_ip6_address, &lbm->ip6_src_address);
+  s = format(s, " #vips: %u\n", pool_elts(lbm->vips));
+  s = format(s, " #ass: %u\n", pool_elts(lbm->ass) - 1);
+
+  u32 cpu_index;
+  for(cpu_index = 0; cpu_index < tm->n_vlib_mains; cpu_index++ ) {
+    lb_hash_t *h = lbm->per_cpu[cpu_index].sticky_ht;
+    if (h) {
+      s = format(s, "core %d\n", cpu_index);
+      s = format(s, "  timeout: %ds\n", h->timeout);
+      s = format(s, "  usage: %d / %d\n", lb_hash_elts(h, lb_hash_time_now(vlib_get_main())),  lb_hash_size(h));
+    }
+  }
+
+  return s;
+}
+
+static char *lb_vip_type_strings[] = {
+    [LB_VIP_TYPE_IP6_GRE6] = "ip6-gre6",
+    [LB_VIP_TYPE_IP6_GRE4] = "ip6-gre4",
+    [LB_VIP_TYPE_IP4_GRE6] = "ip4-gre6",
+    [LB_VIP_TYPE_IP4_GRE4] = "ip4-gre4",
+};
+
+u8 *format_lb_vip_type (u8 * s, va_list * args)
+{
+  lb_vip_type_t vipt = va_arg (*args, lb_vip_type_t);
+  u32 i;
+  for (i=0; i<LB_VIP_N_TYPES; i++)
+    if (vipt == i)
+      return format(s, lb_vip_type_strings[i]);
+  return format(s, "_WRONG_TYPE_");
+}
+
+uword unformat_lb_vip_type (unformat_input_t * input, va_list * args)
+{
+  lb_vip_type_t *vipt = va_arg (*args, lb_vip_type_t *);
+  u32 i;
+  for (i=0; i<LB_VIP_N_TYPES; i++)
+    if (unformat(input, lb_vip_type_strings[i])) {
+      *vipt = i;
+      return 1;
+    }
+  return 0;
+}
+
+u8 *format_lb_vip (u8 * s, va_list * args)
+{
+  lb_vip_t *vip = va_arg (*args, lb_vip_t *);
+  return format(s, "%U %U new_size:%u #as:%u%s",
+             format_lb_vip_type, vip->type,
+             format_ip46_prefix, &vip->prefix, vip->plen, IP46_TYPE_ANY,
+             vip->new_flow_table_mask + 1,
+             pool_elts(vip->as_indexes),
+             (vip->flags & LB_VIP_FLAGS_USED)?"":" removed");
+}
+
+u8 *format_lb_as (u8 * s, va_list * args)
+{
+  lb_as_t *as = va_arg (*args, lb_as_t *);
+  return format(s, "%U %s", format_ip46_address, &as->address, (as->flags & LB_AS_FLAGS_USED)?"used":"removed");
+}
+
+u8 *format_lb_vip_detailed (u8 * s, va_list * args)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip = va_arg (*args, lb_vip_t *);
+  uword indent = format_get_indent (s);
+
+  s = format(s, "%U %U [%u] %U%s\n"
+                   "%U  new_size:%u\n",
+                  format_white_space, indent,
+                  format_lb_vip_type, vip->type,
+                  vip - lbm->vips, format_ip46_prefix, &vip->prefix, vip->plen, IP46_TYPE_ANY,
+                  (vip->flags & LB_VIP_FLAGS_USED)?"":" removed",
+                  format_white_space, indent,
+                  vip->new_flow_table_mask + 1);
+
+  //Print counters
+  s = format(s, "%U  counters:\n",
+             format_white_space, indent);
+  u32 i;
+  for (i=0; i<LB_N_VIP_COUNTERS; i++)
+    s = format(s, "%U    %s: %d\n",
+               format_white_space, indent,
+               lbm->vip_counters[i].name,
+               vlib_get_simple_counter(&lbm->vip_counters[i], vip - lbm->vips));
+
+
+  s = format(s, "%U  #as:%u\n",
+             format_white_space, indent,
+             pool_elts(vip->as_indexes));
+
+  //Let's count the buckets for each AS
+  u32 *count = 0;
+  vec_validate(count, pool_len(lbm->ass)); //Possibly big alloc for not much...
+  lb_new_flow_entry_t *nfe;
+  vec_foreach(nfe, vip->new_flow_table)
+    count[nfe->as_index]++;
+
+  lb_as_t *as;
+  u32 *as_index;
+  pool_foreach(as_index, vip->as_indexes, {
+      as = &lbm->ass[*as_index];
+      s = format(s, "%U    %U %d buckets   %d flows  %s\n", format_white_space, indent,
+                   format_ip46_address, &as->address, IP46_TYPE_ANY,
+                   count[as - lbm->ass],
+                   vlib_refcount_get(&lbm->as_refcount, as - lbm->ass),
+                   (as->flags & LB_AS_FLAGS_USED)?"used":" removed");
+  });
+
+  vec_free(count);
+
+  /*
+  s = format(s, "%U  new flows table:\n", format_white_space, indent);
+  lb_new_flow_entry_t *nfe;
+  vec_foreach(nfe, vip->new_flow_table) {
+    s = format(s, "%U    %d: %d\n", format_white_space, indent, nfe - vip->new_flow_table, nfe->as_index);
+  }
+  */
+  return s;
+}
+
+
+typedef struct {
+  u32 as_index;
+  u32 last;
+  u32 skip;
+} lb_pseudorand_t;
+
+static int lb_pseudorand_compare(void *a, void *b)
+{
+  lb_as_t *asa, *asb;
+  lb_main_t *lbm = &lb_main;
+  asa = &lbm->ass[((lb_pseudorand_t *)a)->as_index];
+  asb = &lbm->ass[((lb_pseudorand_t *)b)->as_index];
+  return memcmp(&asa->address, &asb->address, sizeof(asb->address));
+}
+
+static void lb_vip_garbage_collection(lb_vip_t *vip)
+{
+  lb_main_t *lbm = &lb_main;
+  ASSERT (lbm->writer_lock[0]);
+
+  u32 now = (u32) vlib_time_now(vlib_get_main());
+  if (!clib_u32_loop_gt(now, vip->last_garbage_collection + LB_GARBAGE_RUN))
+    return;
+
+  vip->last_garbage_collection = now;
+  lb_as_t *as;
+  u32 *as_index;
+  pool_foreach(as_index, vip->as_indexes, {
+      as = &lbm->ass[*as_index];
+      if (!(as->flags & LB_AS_FLAGS_USED) && //Not used
+          clib_u32_loop_gt(now, as->last_used + LB_CONCURRENCY_TIMEOUT) && //Not recently used
+          (vlib_refcount_get(&lbm->as_refcount, as - lbm->ass) == 0)) { //Not referenced
+        pool_put(vip->as_indexes, as_index);
+        pool_put(lbm->ass, as);
+      }
+  });
+}
+
+void lb_garbage_collection()
+{
+  lb_main_t *lbm = &lb_main;
+  lb_get_writer_lock();
+  lb_vip_t *vip;
+  u32 *to_be_removed_vips = 0, *i;
+  pool_foreach(vip, lbm->vips, {
+      lb_vip_garbage_collection(vip);
+
+      if (!(vip->flags & LB_VIP_FLAGS_USED) &&
+          (pool_elts(vip->as_indexes) == 0)) {
+        vec_add1(to_be_removed_vips, vip - lbm->vips);
+      }
+  });
+
+  vec_foreach(i, to_be_removed_vips) {
+    vip = &lbm->vips[*i];
+    pool_put(lbm->vips, vip);
+    pool_free(vip->as_indexes);
+  }
+
+  vec_free(to_be_removed_vips);
+  lb_put_writer_lock();
+}
+
+static void lb_vip_update_new_flow_table(lb_vip_t *vip)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_new_flow_entry_t *old_table;
+  u32 i, *as_index;
+  lb_new_flow_entry_t *new_flow_table = 0;
+  lb_as_t *as;
+  lb_pseudorand_t *pr, *sort_arr = 0;
+  u32 count;
+
+  ASSERT (lbm->writer_lock[0]); //We must have the lock
+
+  //Check if some AS is configured or not
+  i = 0;
+  pool_foreach(as_index, vip->as_indexes, {
+      as = &lbm->ass[*as_index];
+      if (as->flags & LB_AS_FLAGS_USED) { //Not used anymore
+        i = 1;
+        goto out; //Not sure 'break' works in this macro-loop
+      }
+  });
+
+out:
+  if (i == 0) {
+    //Only the default. i.e. no AS
+    vec_validate(new_flow_table, vip->new_flow_table_mask);
+    for (i=0; i<vec_len(new_flow_table); i++)
+      new_flow_table[i].as_index = 0;
+
+    goto finished;
+  }
+
+  //First, let's sort the ASs
+  sort_arr = 0;
+  vec_alloc(sort_arr, pool_elts(vip->as_indexes));
+
+  i = 0;
+  pool_foreach(as_index, vip->as_indexes, {
+      as = &lbm->ass[*as_index];
+      if (!(as->flags & LB_AS_FLAGS_USED)) //Not used anymore
+        continue;
+
+      sort_arr[i].as_index = as - lbm->ass;
+      i++;
+  });
+  _vec_len(sort_arr) = i;
+
+  vec_sort_with_function(sort_arr, lb_pseudorand_compare);
+
+  //Now let's pseudo-randomly generate permutations
+  vec_foreach(pr, sort_arr) {
+    lb_as_t *as = &lbm->ass[pr->as_index];
+
+    u64 seed = clib_xxhash(as->address.as_u64[0] ^
+                           as->address.as_u64[1]);
+    /* We have 2^n buckets.
+     * skip must be prime with 2^n.
+     * So skip must be odd.
+     * MagLev actually state that M should be prime,
+     * but this has a big computation cost (% operation).
+     * Using 2^n is more better (& operation).
+     */
+    pr->skip = ((seed & 0xffffffff) | 1) & vip->new_flow_table_mask;
+    pr->last = (seed >> 32) & vip->new_flow_table_mask;
+  }
+
+  //Let's create a new flow table
+  vec_validate(new_flow_table, vip->new_flow_table_mask);
+  for (i=0; i<vec_len(new_flow_table); i++)
+    new_flow_table[i].as_index = ~0;
+
+  u32 done = 0;
+  while (1) {
+    vec_foreach(pr, sort_arr) {
+      while (1) {
+        u32 last = pr->last;
+        pr->last = (pr->last + pr->skip) & vip->new_flow_table_mask;
+        if (new_flow_table[last].as_index == ~0) {
+          new_flow_table[last].as_index = pr->as_index;
+          break;
+        }
+      }
+      done++;
+      if (done == vec_len(new_flow_table))
+        goto finished;
+    }
+  }
+
+  vec_free(sort_arr);
+
+finished:
+
+//Count number of changed entries
+  count = 0;
+  for (i=0; i<vec_len(new_flow_table); i++)
+    if (vip->new_flow_table == 0 ||
+        new_flow_table[i].as_index != vip->new_flow_table[i].as_index)
+      count++;
+
+  old_table = vip->new_flow_table;
+  vip->new_flow_table = new_flow_table;
+  vec_free(old_table);
+}
+
+int lb_conf(ip4_address_t *ip4_address, ip6_address_t *ip6_address,
+           u32 per_cpu_sticky_buckets, u32 flow_timeout)
+{
+  lb_main_t *lbm = &lb_main;
+
+  if (!is_pow2(per_cpu_sticky_buckets))
+    return VNET_API_ERROR_INVALID_MEMORY_SIZE;
+
+  lb_get_writer_lock(); //Not exactly necessary but just a reminder that it exists for my future self
+  lbm->ip4_src_address = *ip4_address;
+  lbm->ip6_src_address = *ip6_address;
+  lbm->per_cpu_sticky_buckets = per_cpu_sticky_buckets;
+  lbm->flow_timeout = flow_timeout;
+  lb_put_writer_lock();
+  return 0;
+}
+
+static
+int lb_vip_find_index_with_lock(ip46_address_t *prefix, u8 plen, u32 *vip_index)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip;
+  ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned
+  ip46_prefix_normalize(prefix, plen);
+  pool_foreach(vip, lbm->vips, {
+      if ((vip->flags & LB_AS_FLAGS_USED) &&
+          vip->plen == plen &&
+          vip->prefix.as_u64[0] == prefix->as_u64[0] &&
+          vip->prefix.as_u64[1] == prefix->as_u64[1]) {
+        *vip_index = vip - lbm->vips;
+        return 0;
+      }
+  });
+  return VNET_API_ERROR_NO_SUCH_ENTRY;
+}
+
+int lb_vip_find_index(ip46_address_t *prefix, u8 plen, u32 *vip_index)
+{
+  int ret;
+  lb_get_writer_lock();
+  ret = lb_vip_find_index_with_lock(prefix, plen, vip_index);
+  lb_put_writer_lock();
+  return ret;
+}
+
+static int lb_as_find_index_vip(lb_vip_t *vip, ip46_address_t *address, u32 *as_index)
+{
+  lb_main_t *lbm = &lb_main;
+  ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned
+  lb_as_t *as;
+  u32 *asi;
+  pool_foreach(asi, vip->as_indexes, {
+      as = &lbm->ass[*asi];
+      if (as->vip_index == (vip - lbm->vips) &&
+          as->address.as_u64[0] == address->as_u64[0] &&
+          as->address.as_u64[1] == address->as_u64[1]) {
+        *as_index = as - lbm->ass;
+        return 0;
+      }
+  });
+  return -1;
+}
+
+int lb_vip_add_ass(u32 vip_index, ip46_address_t *addresses, u32 n)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_get_writer_lock();
+  lb_vip_t *vip;
+  if (!(vip = lb_vip_get_by_index(vip_index))) {
+    lb_put_writer_lock();
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+  }
+
+  ip46_type_t type = lb_vip_is_gre4(vip)?IP46_TYPE_IP4:IP46_TYPE_IP6;
+  u32 *to_be_added = 0;
+  u32 *to_be_updated = 0;
+  u32 i;
+  u32 *ip;
+
+  //Sanity check
+  while (n--) {
+
+    if (!lb_as_find_index_vip(vip, &addresses[n], &i)) {
+      if (lbm->ass[i].flags & LB_AS_FLAGS_USED) {
+        vec_free(to_be_added);
+        vec_free(to_be_updated);
+        lb_put_writer_lock();
+        return VNET_API_ERROR_VALUE_EXIST;
+      }
+      vec_add1(to_be_updated, i);
+      goto next;
+    }
+
+    if (ip46_address_type(&addresses[n]) != type) {
+      vec_free(to_be_added);
+      vec_free(to_be_updated);
+      lb_put_writer_lock();
+      return VNET_API_ERROR_INVALID_ADDRESS_FAMILY;
+    }
+
+    if (n) {
+      u32 n2 = n;
+      while(n2--) //Check for duplicates
+        if (addresses[n2].as_u64[0] == addresses[n].as_u64[0] &&
+            addresses[n2].as_u64[1] == addresses[n].as_u64[1])
+          goto next;
+    }
+
+    vec_add1(to_be_added, n);
+
+next:
+    continue;
+  }
+
+  //Update reused ASs
+  vec_foreach(ip, to_be_updated) {
+    lbm->ass[*ip].flags = LB_AS_FLAGS_USED;
+  }
+  vec_free(to_be_updated);
+
+  //Create those who have to be created
+  vec_foreach(ip, to_be_added) {
+    lb_as_t *as;
+    u32 *as_index;
+    pool_get(lbm->ass, as);
+    as->address = addresses[*ip];
+    as->flags = LB_AS_FLAGS_USED;
+    as->vip_index = vip_index;
+    pool_get(vip->as_indexes, as_index);
+    *as_index = as - lbm->ass;
+  }
+  vec_free(to_be_added);
+
+  //Recompute flows
+  lb_vip_update_new_flow_table(vip);
+
+  //Garbage collection maybe
+  lb_vip_garbage_collection(vip);
+
+  lb_put_writer_lock();
+  return 0;
+}
+
+int lb_vip_del_ass_withlock(u32 vip_index, ip46_address_t *addresses, u32 n)
+{
+  lb_main_t *lbm = &lb_main;
+  u32 now = (u32) vlib_time_now(vlib_get_main());
+  u32 *ip = 0;
+
+  lb_vip_t *vip;
+  if (!(vip = lb_vip_get_by_index(vip_index))) {
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+  }
+
+  u32 *indexes = NULL;
+  while (n--) {
+    u32 i;
+    if (lb_as_find_index_vip(vip, &addresses[n], &i)) {
+      vec_free(indexes);
+      return VNET_API_ERROR_NO_SUCH_ENTRY;
+    }
+
+    if (n) { //Check for duplicates
+      u32 n2 = n - 1;
+      while(n2--) {
+        if (addresses[n2].as_u64[0] == addresses[n].as_u64[0] &&
+            addresses[n2].as_u64[1] == addresses[n].as_u64[1])
+          goto next;
+      }
+    }
+
+    vec_add1(indexes, i);
+next:
+  continue;
+  }
+
+  //Garbage collection maybe
+  lb_vip_garbage_collection(vip);
+
+  if (indexes != NULL) {
+    vec_foreach(ip, indexes) {
+      lbm->ass[*ip].flags &= ~LB_AS_FLAGS_USED;
+      lbm->ass[*ip].last_used = now;
+    }
+
+    //Recompute flows
+    lb_vip_update_new_flow_table(vip);
+  }
+
+  vec_free(indexes);
+  return 0;
+}
+
+int lb_vip_del_ass(u32 vip_index, ip46_address_t *addresses, u32 n)
+{
+  lb_get_writer_lock();
+  int ret = lb_vip_del_ass_withlock(vip_index, addresses, n);
+  lb_put_writer_lock();
+  return ret;
+}
+
+
+/**
+ * Add the VIP adjacency to the ip4 or ip6 fib
+ */
+static void lb_vip_add_adjacency(lb_main_t *lbm, lb_vip_t *vip)
+{
+  ip_adjacency_t adj;
+  //Adjacency
+  memset (&adj, 0, sizeof (adj));
+  adj.explicit_fib_index = ~0;
+  lb_adj_data_t *ad = (lb_adj_data_t *) &adj.opaque;
+  ad->vip_index = vip - lbm->vips;
+
+  ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned
+  u32 lookup_next_index = lbm->ip_lookup_next_index[vip->type];
+
+  if (lb_vip_is_ip4(vip)) {
+    adj.lookup_next_index = lookup_next_index;
+    ip4_add_del_route_args_t route_args = {};
+    ip4_main_t *im4 = &ip4_main;
+    route_args.table_index_or_table_id = 0;
+    route_args.flags = IP4_ROUTE_FLAG_ADD;
+    route_args.dst_address = vip->prefix.ip4;
+    route_args.dst_address_length = vip->plen - 96;
+    route_args.adj_index = ~0;
+    route_args.add_adj = &adj;
+    route_args.n_add_adj = 1;
+    ip4_add_del_route (im4, &route_args);
+  } else {
+    adj.lookup_next_index = lookup_next_index;
+    ip6_add_del_route_args_t route_args = {};
+    ip6_main_t *im6 = &ip6_main;
+    route_args.table_index_or_table_id = 0;
+    route_args.flags = IP6_ROUTE_FLAG_ADD;
+    route_args.dst_address = vip->prefix.ip6;
+    route_args.dst_address_length = vip->plen;
+    route_args.adj_index = ~0;
+    route_args.add_adj = &adj;
+    route_args.n_add_adj = 1;
+    ip6_add_del_route (im6, &route_args);
+  }
+}
+
+/**
+ * Deletes the adjacency associated with the VIP
+ */
+static void lb_vip_del_adjacency(lb_main_t *lbm, lb_vip_t *vip)
+{
+  ASSERT (lbm->writer_lock[0]); //This must be called with the lock owned
+  if (lb_vip_is_ip4(vip)) {
+    ip4_main_t *im4 = &ip4_main;
+    ip4_add_del_route_args_t route_args = {};
+    route_args.table_index_or_table_id = 0;
+    route_args.flags = IP4_ROUTE_FLAG_DEL;
+    route_args.dst_address = vip->prefix.ip4;
+    route_args.dst_address_length = vip->plen - 96;
+    route_args.adj_index = ~0;
+    route_args.add_adj = NULL;
+    route_args.n_add_adj = 0;
+    ip4_add_del_route (im4, &route_args);
+  } else {
+    ip6_main_t *im6 = &ip6_main;
+    ip6_add_del_route_args_t route_args = {};
+    route_args.table_index_or_table_id = 0;
+    route_args.flags = IP6_ROUTE_FLAG_DEL;
+    route_args.dst_address = vip->prefix.ip6;
+    route_args.dst_address_length = vip->plen;
+    route_args.adj_index = ~0;
+    route_args.add_adj = NULL;
+    route_args.n_add_adj = 0;
+    ip6_add_del_route (im6, &route_args);
+  }
+}
+
+int lb_vip_add(ip46_address_t *prefix, u8 plen, lb_vip_type_t type, u32 new_length, u32 *vip_index)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip;
+  lb_get_writer_lock();
+  ip46_prefix_normalize(prefix, plen);
+
+  if (!lb_vip_find_index_with_lock(prefix, plen, vip_index)) {
+    lb_put_writer_lock();
+    return VNET_API_ERROR_VALUE_EXIST;
+  }
+
+  if (!is_pow2(new_length)) {
+    lb_put_writer_lock();
+    return VNET_API_ERROR_INVALID_MEMORY_SIZE;
+  }
+
+  if (ip46_prefix_is_ip4(prefix, plen) &&
+      (type != LB_VIP_TYPE_IP4_GRE4) &&
+      (type != LB_VIP_TYPE_IP4_GRE6))
+    return VNET_API_ERROR_INVALID_ADDRESS_FAMILY;
+
+
+  //Allocate
+  pool_get(lbm->vips, vip);
+
+  //Init
+  vip->prefix = *prefix;
+  vip->plen = plen;
+  vip->last_garbage_collection = (u32) vlib_time_now(vlib_get_main());
+  vip->type = type;
+  vip->flags = LB_VIP_FLAGS_USED;
+  vip->as_indexes = 0;
+
+  //Validate counters
+  u32 i;
+  for (i = 0; i < LB_N_VIP_COUNTERS; i++) {
+    vlib_validate_simple_counter(&lbm->vip_counters[i], vip - lbm->vips);
+    vlib_zero_simple_counter(&lbm->vip_counters[i], vip - lbm->vips);
+  }
+
+  //Configure new flow table
+  vip->new_flow_table_mask = new_length - 1;
+  vip->new_flow_table = 0;
+
+  //Create a new flow hash table full of the default entry
+  lb_vip_update_new_flow_table(vip);
+
+  //Create adjacency to direct traffic
+  lb_vip_add_adjacency(lbm, vip);
+
+  //Return result
+  *vip_index = vip - lbm->vips;
+
+  lb_put_writer_lock();
+  return 0;
+}
+
+int lb_vip_del(u32 vip_index)
+{
+  lb_main_t *lbm = &lb_main;
+  lb_vip_t *vip;
+  lb_get_writer_lock();
+  if (!(vip = lb_vip_get_by_index(vip_index))) {
+    lb_put_writer_lock();
+    return VNET_API_ERROR_NO_SUCH_ENTRY;
+  }
+
+  //FIXME: This operation is actually not working
+  //We will need to remove state before performing this.
+
+  {
+    //Remove all ASs
+    ip46_address_t *ass = 0;
+    lb_as_t *as;
+    u32 *as_index;
+    pool_foreach(as_index, vip->as_indexes, {
+        as = &lbm->ass[*as_index];
+        vec_add1(ass, as->address);
+    });
+    if (vec_len(ass))
+      lb_vip_del_ass_withlock(vip_index, ass, vec_len(ass));
+    vec_free(ass);
+  }
+
+  //Delete adjacency
+  lb_vip_del_adjacency(lbm, vip);
+
+  //Set the VIP as unused
+  vip->flags &= ~LB_VIP_FLAGS_USED;
+
+  lb_put_writer_lock();
+  return 0;
+}
+
+clib_error_t *
+vlib_plugin_register (vlib_main_t * vm,
+                      vnet_plugin_handoff_t * h,
+                      int from_early_init)
+{
+  clib_error_t *error = 0;
+  return error;
+}
+
+clib_error_t *
+lb_init (vlib_main_t * vm)
+{
+  vlib_thread_main_t *tm = vlib_get_thread_main ();
+  lb_main_t *lbm = &lb_main;
+  lb_as_t *default_as;
+  lbm->vips = 0;
+  lbm->per_cpu = 0;
+  vec_validate(lbm->per_cpu, tm->n_vlib_mains - 1);
+  lbm->writer_lock = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES,  CLIB_CACHE_LINE_BYTES);
+  lbm->writer_lock[0] = 0;
+  lbm->per_cpu_sticky_buckets = LB_DEFAULT_PER_CPU_STICKY_BUCKETS;
+  lbm->flow_timeout = LB_DEFAULT_FLOW_TIMEOUT;
+  lbm->ip4_src_address.as_u32 = 0xffffffff;
+  lbm->ip6_src_address.as_u64[0] = 0xffffffffffffffffL;
+  lbm->ip6_src_address.as_u64[1] = 0xffffffffffffffffL;
+
+  //Init AS reference counters
+  vlib_refcount_init(&lbm->as_refcount);
+
+  //Allocate and init default AS.
+  lbm->ass = 0;
+  pool_get(lbm->ass, default_as);
+  default_as->flags = 0;
+  default_as->vip_index = ~0;
+  default_as->address.ip6.as_u64[0] = 0xffffffffffffffffL;
+  default_as->address.ip6.as_u64[1] = 0xffffffffffffffffL;
+
+#define _(a,b,c) lbm->vip_counters[c].name = b;
+  lb_foreach_vip_counter
+#undef _
+  return NULL;
+}
+
+VLIB_INIT_FUNCTION (lb_init);