PeerStreamer

/*

 *  Copyright (c) 2010 Luca Abeni

 *

 *  This is free software; see lgpl-2.1.txt

 */

#include <sys/time.h>

#include <time.h>

#include <stdlib.h>

#include <stdint.h>

#include <stdio.h>

#include <stdbool.h>

#include <string.h>

#include "net_helper.h"

#include "peersampler_iface.h"

#include "../Cache/topocache.h"

#include "../Cache/cyclon_proto.h"

#include "../Cache/proto.h"

#include "config.h"

#include "grapes_msg_types.h"

#define DEFAULT_CACHE_SIZE 10

struct peersampler_context{

  uint64_t currtime;

  int cache_size;

  int sent_entries;

  struct peer_cache *local_cache;

  bool bootstrap;

  int bootstrap_period;

  int period;

  struct peer_cache *flying_cache;

  struct nodeID *dst;

  struct cyclon_proto_context *pc;

  const struct nodeID **r;

};

static uint64_t gettime(void)

{

  struct timeval tv;

  gettimeofday(&tv, NULL);

  return tv.tv_usec + tv.tv_sec * 1000000ull;

}

static struct peersampler_context* cyclon_context_init(void)

{

  struct peersampler_context* con;

  con = (struct peersampler_context*) calloc(1,sizeof(struct peersampler_context));

  //Initialize context with default values

  con->bootstrap = true;

  con->bootstrap_period = 2000000;

  con->period = 10000000;

  con->currtime = gettime();

  return con;

}

static int time_to_send(struct peersampler_context* con)

{

  int p = con->bootstrap ? con->bootstrap_period : con->period;

  if (gettime() - con->currtime > p) {

    con->currtime += p;

    return 1;

  }

  return 0;

}

/*

 * Public Functions!

 */

static struct peersampler_context* cyclon_init(struct nodeID *myID, const void *metadata, int metadata_size, const char *config)

{

  struct tag *cfg_tags;

  struct peersampler_context *con;

  int res;

  con = cyclon_context_init();

  if (!con) return NULL;

  cfg_tags = config_parse(config);

  res = config_value_int(cfg_tags, "cache_size", &(con->cache_size));

  if (!res) {

    con->cache_size = DEFAULT_CACHE_SIZE;

  }

  res = config_value_int(cfg_tags, "sent_entries", &(con->sent_entries));

  if (!res) {

    con->sent_entries = con->cache_size / 2;

  }

  free(cfg_tags);

  con->local_cache = cache_init(con->cache_size, metadata_size, 0);

  if (con->local_cache == NULL) {

    free(con);

    return NULL;

  }

  con->pc = cyclon_proto_init(myID, metadata, metadata_size);

  if (!con->pc){

    free(con->local_cache);

    free(con);

    return NULL;

  }

  return con;

}

static int cyclon_add_neighbour(struct peersampler_context *context, struct nodeID *neighbour, const void *metadata, int metadata_size)

{

  if (!context->flying_cache) {

    context->flying_cache = rand_cache(context->local_cache, context->sent_entries - 1);

  }

  if (cache_add(context->local_cache, neighbour, metadata, metadata_size) < 0) {

    return -1;

  }

  return cyclon_query(context->pc, context->flying_cache, neighbour);

}

static int cyclon_parse_data(struct peersampler_context *context, const uint8_t *buff, int len)

{

  cache_check(context->local_cache);

  if (len) {

    const struct topo_header *h = (const struct topo_header *)buff;

    struct peer_cache *remote_cache;

    struct peer_cache *sent_cache = NULL;

    if (h->protocol != MSG_TYPE_TOPOLOGY) {

      fprintf(stderr, "Peer Sampler: Wrong protocol!\n");

      return -1;

    }

    context->bootstrap = false;

    remote_cache = entries_undump(buff + sizeof(struct topo_header), len - sizeof(struct topo_header));

    if (h->type == CYCLON_QUERY) {

      sent_cache = rand_cache(context->local_cache, context->sent_entries);

      cyclon_reply(context->pc, remote_cache, sent_cache);

      nodeid_free(context->dst);

      context->dst = NULL;

    }

    cache_check(context->local_cache);

    cache_add_cache(context->local_cache, remote_cache);

    cache_free(remote_cache);

    if (sent_cache) {

      cache_add_cache(context->local_cache, sent_cache);

      cache_free(sent_cache);

    } else {

      if (context->flying_cache) {

        cache_add_cache(context->local_cache, context->flying_cache);

        cache_free(context->flying_cache);

        context->flying_cache = NULL;

      }

    }

  }

  if (time_to_send(context)) {

    if (context->flying_cache) {

      cache_add_cache(context->local_cache, context->flying_cache);

      cache_free(context->flying_cache);

      context->flying_cache = NULL;

    }

    cache_update(context->local_cache);

    nodeid_free(context->dst);

    context->dst = last_peer(context->local_cache);

    if (context->dst == NULL) {

      return 0;

    }

    context->dst = nodeid_dup(context->dst);

    cache_del(context->local_cache, context->dst);

    context->flying_cache = rand_cache(context->local_cache, context->sent_entries - 1);

    return cyclon_query(context->pc, context->flying_cache, context->dst);

  }

  cache_check(context->local_cache);

  return 0;

}

static const struct nodeID **cyclon_get_neighbourhood(struct peersampler_context *context, int *n)

{

  context->r = realloc(context->r, context->cache_size * sizeof(struct nodeID *));

  if (context->r == NULL) {

    return NULL;

  }

  for (*n = 0; nodeid(context->local_cache, *n) && (*n < context->cache_size); (*n)++) {

    context->r[*n] = nodeid(context->local_cache, *n);

    //fprintf(stderr, "Checking table[%d]\n", *n);

  }

  if (context->flying_cache) {

    int i;

    for (i = 0; nodeid(context->flying_cache, i) && (*n < context->cache_size); (*n)++, i++) {

      context->r[*n] = nodeid(context->flying_cache, i);

    }

  }

  if (context->dst && (*n < context->cache_size)) {

    context->r[*n] = context->dst;

    (*n)++;

  }

  return context->r;

}

static const void *cyclon_get_metadata(struct peersampler_context *context, int *metadata_size)

{

  return get_metadata(context->local_cache, metadata_size);

}

static int cyclon_grow_neighbourhood(struct peersampler_context *context, int n)

{

  context->cache_size += n;

  return context->cache_size;

}

static int cyclon_shrink_neighbourhood(struct peersampler_context *context, int n)

{

  if (context->cache_size < n) {

    return -1;

  }

  context->cache_size -= n;

  return context->cache_size;

}

static int cyclon_remove_neighbour(struct peersampler_context *context, const struct nodeID *neighbour)

{

  return cache_del(context->local_cache, neighbour);

}

static int cyclon_change_metadata(struct peersampler_context *context, const void *metadata, int metadata_size)

{

  return cyclon_proto_change_metadata(context->pc, metadata, metadata_size);

}

struct peersampler_iface cyclon = {

  .init = cyclon_init,

  .change_metadata = cyclon_change_metadata,

  .add_neighbour = cyclon_add_neighbour,

  .parse_data = cyclon_parse_data,

  .get_neighbourhood = cyclon_get_neighbourhood,

  .get_metadata = cyclon_get_metadata,

  .grow_neighbourhood = cyclon_grow_neighbourhood,

  .shrink_neighbourhood = cyclon_shrink_neighbourhood,

  .remove_neighbour = cyclon_remove_neighbour,

};