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grapes / src / PeerSampler / cyclon.c @ 43b793e3

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/*
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 *  Copyright (c) 2010 Luca Abeni
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 *
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 *  This is free software; see lgpl-2.1.txt
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 */
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#include <sys/time.h>
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#include <time.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <string.h>
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#include "net_helper.h"
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#include "peersampler_iface.h"
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#include "../Cache/topocache.h"
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#include "../Cache/cyclon_proto.h"
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#include "../Cache/proto.h"
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#include "config.h"
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#include "grapes_msg_types.h"
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#define DEFAULT_CACHE_SIZE 10
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struct peersampler_context{
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  uint64_t currtime;
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  int cache_size;
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  int sent_entries;
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  struct peer_cache *local_cache;
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  bool bootstrap;
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  int bootstrap_period;
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  int period;
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  struct peer_cache *flying_cache;
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  struct nodeID *dst;
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  struct cyclon_proto_context *pc;
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  const struct nodeID **r;
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};
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static uint64_t gettime(void)
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{
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  struct timeval tv;
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  gettimeofday(&tv, NULL);
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  return tv.tv_usec + tv.tv_sec * 1000000ull;
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}
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static struct peersampler_context* cyclon_context_init(void)
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{
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  struct peersampler_context* con;
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  con = (struct peersampler_context*) calloc(1,sizeof(struct peersampler_context));
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  //Initialize context with default values
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  con->bootstrap = true;
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  con->bootstrap_period = 2000000;
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  con->period = 10000000;
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  con->currtime = gettime();
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  return con;
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}
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static int time_to_send(struct peersampler_context* con)
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{
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  int p = con->bootstrap ? con->bootstrap_period : con->period;
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  if (gettime() - con->currtime > p) {
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    con->currtime += p;
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    return 1;
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  }
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  return 0;
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}
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/*
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 * Public Functions!
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 */
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static struct peersampler_context* cyclon_init(struct nodeID *myID, const void *metadata, int metadata_size, const char *config)
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{
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  struct tag *cfg_tags;
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  struct peersampler_context *con;
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  int res;
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  con = cyclon_context_init();
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  if (!con) return NULL;
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  cfg_tags = config_parse(config);
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  res = config_value_int(cfg_tags, "cache_size", &(con->cache_size));
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  if (!res) {
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    con->cache_size = DEFAULT_CACHE_SIZE;
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  }
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  res = config_value_int(cfg_tags, "sent_entries", &(con->sent_entries));
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  if (!res) {
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    con->sent_entries = con->cache_size / 2;
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  }
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  free(cfg_tags);
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  con->local_cache = cache_init(con->cache_size, metadata_size, 0);
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  if (con->local_cache == NULL) {
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    free(con);
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    return NULL;
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  }
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  con->pc = cyclon_proto_init(myID, metadata, metadata_size);
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  if (!con->pc){
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    free(con->local_cache);
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    free(con);
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    return NULL;
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  }
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  return con;
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}
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static int cyclon_add_neighbour(struct peersampler_context *context, struct nodeID *neighbour, const void *metadata, int metadata_size)
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{
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  if (!context->flying_cache) {
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    context->flying_cache = rand_cache(context->local_cache, context->sent_entries - 1);
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  }
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  if (cache_add(context->local_cache, neighbour, metadata, metadata_size) < 0) {
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    return -1;
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  }
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  return cyclon_query(context->pc, context->flying_cache, neighbour);
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}
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static int cyclon_parse_data(struct peersampler_context *context, const uint8_t *buff, int len)
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{
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  cache_check(context->local_cache);
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  if (len) {
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    const struct topo_header *h = (const struct topo_header *)buff;
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    struct peer_cache *remote_cache;
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    struct peer_cache *sent_cache = NULL;
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    if (h->protocol != MSG_TYPE_TOPOLOGY) {
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      fprintf(stderr, "Peer Sampler: Wrong protocol!\n");
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      return -1;
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    }
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    context->bootstrap = false;
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    remote_cache = entries_undump(buff + sizeof(struct topo_header), len - sizeof(struct topo_header));
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    if (h->type == CYCLON_QUERY) {
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      sent_cache = rand_cache(context->local_cache, context->sent_entries);
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      cyclon_reply(context->pc, remote_cache, sent_cache);
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      context->dst = NULL;
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    }
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    cache_check(context->local_cache);
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    cache_add_cache(context->local_cache, remote_cache);
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    cache_free(remote_cache);
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    if (sent_cache) {
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      cache_add_cache(context->local_cache, sent_cache);
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      cache_free(sent_cache);
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    } else {
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      if (context->flying_cache) {
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        cache_add_cache(context->local_cache, context->flying_cache);
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        cache_free(context->flying_cache);
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        context->flying_cache = NULL;
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      }
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    }
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  }
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  if (time_to_send(context)) {
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    if (context->flying_cache) {
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      cache_add_cache(context->local_cache, context->flying_cache);
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      cache_free(context->flying_cache);
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      context->flying_cache = NULL;
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    }
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    cache_update(context->local_cache);
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    context->dst = last_peer(context->local_cache);
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    if (context->dst == NULL) {
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      return 0;
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    }
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    context->dst = nodeid_dup(context->dst);
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    cache_del(context->local_cache, context->dst);
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    context->flying_cache = rand_cache(context->local_cache, context->sent_entries - 1);
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    return cyclon_query(context->pc, context->flying_cache, context->dst);
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  }
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  cache_check(context->local_cache);
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  return 0;
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}
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static const struct nodeID **cyclon_get_neighbourhood(struct peersampler_context *context, int *n)
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{
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  context->r = realloc(context->r, context->cache_size * sizeof(struct nodeID *));
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  if (context->r == NULL) {
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    return NULL;
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  }
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  for (*n = 0; nodeid(context->local_cache, *n) && (*n < context->cache_size); (*n)++) {
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    context->r[*n] = nodeid(context->local_cache, *n);
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    //fprintf(stderr, "Checking table[%d]\n", *n);
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  }
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  if (context->flying_cache) {
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    int i;
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    for (i = 0; nodeid(context->flying_cache, i) && (*n < context->cache_size); (*n)++, i++) {
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      context->r[*n] = nodeid(context->flying_cache, i);
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    }
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  }
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  if (context->dst && (*n < context->cache_size)) {
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    context->r[*n] = context->dst;
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    (*n)++;
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  }
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  return context->r;
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}
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static const void *cyclon_get_metadata(struct peersampler_context *context, int *metadata_size)
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{
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  return get_metadata(context->local_cache, metadata_size);
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}
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static int cyclon_grow_neighbourhood(struct peersampler_context *context, int n)
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{
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  context->cache_size += n;
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  return context->cache_size;
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}
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static int cyclon_shrink_neighbourhood(struct peersampler_context *context, int n)
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{
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  if (context->cache_size < n) {
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    return -1;
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  }
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  context->cache_size -= n;
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  return context->cache_size;
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}
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static int cyclon_remove_neighbour(struct peersampler_context *context, const struct nodeID *neighbour)
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{
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  return cache_del(context->local_cache, neighbour);
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}
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static int cyclon_change_metadata(struct peersampler_context *context, const void *metadata, int metadata_size)
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{
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  return cyclon_proto_change_metadata(context->pc, metadata, metadata_size);
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}
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struct peersampler_iface cyclon = {
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  .init = cyclon_init,
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  .change_metadata = cyclon_change_metadata,
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  .add_neighbour = cyclon_add_neighbour,
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  .parse_data = cyclon_parse_data,
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  .get_neighbourhood = cyclon_get_neighbourhood,
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  .get_metadata = cyclon_get_metadata,
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  .grow_neighbourhood = cyclon_grow_neighbourhood,
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  .shrink_neighbourhood = cyclon_shrink_neighbourhood,
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  .remove_neighbour = cyclon_remove_neighbour,
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};