PeerStreamer-ng

/*

 * Copyright (c) 2010-2011 Luca Abeni

 * Copyright (c) 2010-2011 Csaba Kiraly

 * Copyright (c) 2017 Luca Baldesi

 *

 * This file is part of PeerStreamer.

 *

 * PeerStreamer is free software: you can redistribute it and/or

 * modify it under the terms of the GNU Affero General Public License as

 * published by the Free Software Foundation, either version 3 of the

 * License, or (at your option) any later version.

 *

 * PeerStreamer is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero

 * General Public License for more details.

 *

 * You should have received a copy of the GNU Affero General Public License

 * along with PeerStreamer.  If not, see <http://www.gnu.org/licenses/>.

 *

 */

#include <sys/time.h>

#include <stdlib.h>

#include <stdio.h>

#include <stdint.h>

#include <stdbool.h>

#include <math.h>

#include <assert.h>

#include <string.h>

#include <inttypes.h>

#include <net_helper.h>

#include <chunk.h> 

#include <chunkbuffer.h> 

#include <trade_msg_la.h>

#include <trade_msg_ha.h>

#include <peerset.h>

#include <peer.h>

#include <chunkidset.h>

#include <limits.h>

#include <trade_sig_ha.h>

#ifdef CHUNK_ATTRIB_CHUNKER

#include <chunkiser_attrib.h>

#endif

#include "streaming.h"

#include "output.h"

#include "input.h"

#include "dbg.h"

#include "chunk_signaling.h"

#include "chunklock.h"

#include "topology.h"

#include "measures.h"

#include "net_helpers.h"

#include "scheduling.h"

#include "transaction.h"

#include "scheduler_la.h"

# define CB_SIZE_TIME_UNLIMITED 1e12

void selectPeersForChunks(SchedOrdering ordering, schedPeerID *peers, size_t peers_len, schedChunkID *chunks, size_t chunks_len, schedPeerID *selected, size_t *selected_len, filterFunction filter, peerEvaluateFunction evaluate);

struct chunk_attributes {

  uint64_t deadline;

  uint16_t deadline_increment;

  uint16_t hopcount;

} __attribute__((packed));

struct streaming_context {

        struct chunk_buffer *cb;

        struct input_desc *input;

        struct chunk_locks * ch_locks;

        struct service_times_element * transactions;

        const struct psinstance * ps;

        int cb_size;

        int bcast_after_receive_every;

        bool neigh_on_chunk_recv;

        bool send_bmap_before_push;

        uint64_t CB_SIZE_TIME;

        uint32_t chunk_loss_interval;

};

struct streaming_context * streaming_create(const struct psinstance * ps, struct input_context * inc, const char * config)

{

        struct streaming_context * stc;

        static char conf[80];

        stc = malloc(sizeof(struct streaming_context));

        stc->bcast_after_receive_every = 0;

        stc->neigh_on_chunk_recv = false;

        stc->send_bmap_before_push = false;

        stc->transactions = NULL;

        stc->CB_SIZE_TIME = CB_SIZE_TIME_UNLIMITED;        //in millisec, defaults to unlimited

        stc->chunk_loss_interval = 0;  // disable self-lossy feature (for experiments)

        stc->input = inc ? input_open(inc->filename, inc->fds, inc->fds_size, config) : NULL;

        stc->ps = ps;

        stc->cb_size = psinstance_chunkbuffer_size(ps);

        sprintf(conf, "size=%d", stc->cb_size);

        stc->cb = cb_init(conf);

        chunkDeliveryInit(psinstance_nodeid(ps));

        chunkSignalingInit(psinstance_nodeid(ps));

        stc->ch_locks = chunk_locks_create();

        return stc;

}

void streaming_destroy(struct streaming_context ** stc)

{

        if (stc && *stc)

        {

                if((*stc)->input)

                        input_close((*stc)->input);

                if(((*stc)->ch_locks))

                        chunk_locks_destroy(&((*stc)->ch_locks));

                if(((*stc)->transactions))

                        transaction_destroy(&((*stc)->transactions));

                if(((*stc)->cb))

                        cb_destroy((*stc)->cb);

                free((*stc));

        }

}

int _needs(const struct streaming_context * stc, struct chunkID_set *cset, int cb_size, int cid);

uint64_t gettimeofday_in_us(void)

{

  struct timeval what_time; //to store the epoch time

  gettimeofday(&what_time, NULL);

  return what_time.tv_sec * 1000000ULL + what_time.tv_usec;

}

void cb_print(const struct streaming_context * stc)

{

#ifdef DEBUG

  struct chunk *chunks;

  int num_chunks, i, id;

  chunks = cb_get_chunks(stc->cb, &num_chunks);

  dprintf("\tchbuf :");

  i = 0;

  if(num_chunks) {

    id = chunks[0].id;

    dprintf(" %d-> ",id);

    while (i < num_chunks) {

      if (id == chunks[i].id) {

        dprintf("%d",id % 10);

        i++;

      } else if (chunk_islocked(stc->ch_locks, id)) {

        dprintf("*");

      } else {

        dprintf(".");

      }

      id++;

    }

  }

  dprintf("\n");

#endif

}

void chunk_attributes_fill(struct chunk* c)

{

  struct chunk_attributes * ca;

  int priority = 1;

  assert((!c->attributes && c->attributes_size == 0)

#ifdef CHUNK_ATTRIB_CHUNKER

      || chunk_attributes_chunker_verify(c->attributes, c->attributes_size)

#endif

  );

#ifdef CHUNK_ATTRIB_CHUNKER

  if (chunk_attributes_chunker_verify(c->attributes, c->attributes_size)) {

    priority = ((struct chunk_attributes_chunker*) c->attributes)->priority;

    free(c->attributes);

    c->attributes = NULL;

    c->attributes_size = 0;

  }

#endif

  c->attributes_size = sizeof(struct chunk_attributes);

  c->attributes = ca = malloc(c->attributes_size);

  ca->deadline = c->id;

  ca->deadline_increment = priority * 2;

  ca->hopcount = 0;

}

int chunk_get_hopcount(const struct chunk* c) {

  struct chunk_attributes * ca;

  if (!c->attributes || c->attributes_size != sizeof(struct chunk_attributes)) {

    fprintf(stderr,"Warning, chunk %d with strange attributes block. Size:%d expected:%lu\n", c->id, c->attributes ? c->attributes_size : 0, sizeof(struct chunk_attributes));

    return -1;

  }

  ca = (struct chunk_attributes *) c->attributes;

  return ca->hopcount;

}

void chunk_attributes_update_received(struct chunk* c)

{

  struct chunk_attributes * ca;

  if (!c->attributes || c->attributes_size != sizeof(struct chunk_attributes)) {

    fprintf(stderr,"Warning, received chunk %d with strange attributes block. Size:%d expected:%lu\n", c->id, c->attributes ? c->attributes_size : 0, sizeof(struct chunk_attributes));

    return;

  }

  ca = (struct chunk_attributes *) c->attributes;

  ca->hopcount++;

  dprintf("Received chunk %d with hopcount %hu\n", c->id, ca->hopcount);

}

void chunk_attributes_update_sending(const struct chunk* c)

{

  struct chunk_attributes * ca;

  if (!c->attributes || c->attributes_size != sizeof(struct chunk_attributes)) {

    fprintf(stderr,"Warning, chunk %d with strange attributes block\n", c->id);

    return;

  }

  ca = (struct chunk_attributes *) c->attributes;

  ca->deadline += ca->deadline_increment;

  dprintf("Sending chunk %d with deadline %lu (increment: %d)\n", c->id, ca->deadline, ca->deadline_increment);

}

struct chunkID_set *cb_to_bmap(struct chunk_buffer *chbuf)

{

  struct chunk *chunks;

  int num_chunks, i;

  struct chunkID_set *my_bmap = chunkID_set_init("type=bitmap");

  chunks = cb_get_chunks(chbuf, &num_chunks);

  for(i=num_chunks-1; i>=0; i--) {

    chunkID_set_add_chunk(my_bmap, chunks[i].id);

  }

  return my_bmap;

}

// a simple implementation that request everything that we miss ... up to max deliver

struct chunkID_set *get_chunks_to_accept(const struct streaming_context * stc, struct nodeID *fromid, const struct chunkID_set *cset_off, int max_deliver, uint16_t trans_id){

  struct chunkID_set *cset_acc, *my_bmap;

  int i, d, cset_off_size;

  //double lossrate;

  struct peer *from = nodeid_to_peer(psinstance_topology(stc->ps), fromid, 0);

  cset_acc = chunkID_set_init("size=0");

  //reduce load a little bit if there are losses on the path from this guy

  //lossrate = get_lossrate_receive(from->id);

  //lossrate = finite(lossrate) ? lossrate : 0;        //start agressively, assuming 0 loss

  //if (rand()/((double)RAND_MAX + 1) >= 10 * lossrate ) {

    my_bmap = cb_to_bmap(stc->cb);

    cset_off_size = chunkID_set_size(cset_off);

    for (i = 0, d = 0; i < cset_off_size && d < max_deliver; i++) {

      int chunkid = chunkID_set_get_chunk(cset_off, i);

      //dprintf("\tdo I need c%d ? :",chunkid);

      if (!chunk_islocked(stc->ch_locks, chunkid) && _needs(stc, my_bmap, stc->cb_size, chunkid)) {

        chunkID_set_add_chunk(cset_acc, chunkid);

        chunk_lock(stc->ch_locks, chunkid,from);

        dtprintf("accepting %d from %s", chunkid, nodeid_static_str(fromid));

#ifdef MONL

        dprintf(", loss:%f rtt:%f", get_lossrate(fromid), get_rtt(fromid));

#endif

        dprintf("\n");

        d++;

      }

    }

    chunkID_set_free(my_bmap);

  //} else {

  //    dtprintf("accepting -- from %s loss:%f rtt:%f\n", node_addr_tr(fromid), lossrate, get_rtt(fromid));

  //}

  reg_offer_accept_in(psinstance_measures(stc->ps), chunkID_set_size(cset_acc) > 0 ? 1 : 0);

  return cset_acc;

}

void send_bmap(const struct streaming_context *stc, const struct nodeID *toid)

{

  struct chunkID_set *my_bmap = cb_to_bmap(stc->cb);

   sendBufferMap(psinstance_nodeid(stc->ps), toid, NULL, my_bmap, psinstance_is_source(stc->ps) ? 0 : stc->cb_size, 0);

#ifdef LOG_SIGNAL

        log_signal(psinstance_nodeid(stc->ps),toid,chunkID_set_size(my_bmap),0,sig_send_buffermap,"SENT");

#endif

  chunkID_set_free(my_bmap);

}

void bcast_bmap(const struct streaming_context * stc)

{

  int i, n;

  struct peer **neighbours;

  struct peerset *pset;

  struct chunkID_set *my_bmap;

  pset = topology_get_neighbours(psinstance_topology(stc->ps));

  n = peerset_size(pset);

  neighbours = peerset_get_peers(pset);

  my_bmap = cb_to_bmap(stc->cb);        //cache our bmap for faster processing

  for (i = 0; i<n; i++) {

    sendBufferMap(psinstance_nodeid(stc->ps),neighbours[i]->id,NULL, my_bmap, psinstance_is_source(stc->ps) ? 0 : stc->cb_size, 0);

#ifdef LOG_SIGNAL

                 log_signal(psinstance_nodeid(stc->ps),neighbours[i]->id,chunkID_set_size(my_bmap),0,sig_send_buffermap,"SENT");

#endif

  }

  chunkID_set_free(my_bmap);

}

void send_ack(const struct streaming_context * stc, struct nodeID *toid, uint16_t trans_id)

{

  struct chunkID_set *my_bmap = cb_to_bmap(stc->cb);

  sendAck(psinstance_nodeid(stc->ps),toid, my_bmap,trans_id);

#ifdef LOG_SIGNAL

        log_signal(psinstance_nodeid(stc->ps),toid,chunkID_set_size(my_bmap),trans_id,sig_ack,"SENT");

#endif

  chunkID_set_free(my_bmap);

}

double get_average_lossrate_pset(struct peerset *pset)

{

  return 0;

}

void ack_chunk(const struct streaming_context * stc, struct chunk *c, struct nodeID *from, uint16_t trans_id)

{

  //reduce load a little bit if there are losses on the path from this guy

  double average_lossrate = get_average_lossrate_pset(topology_get_neighbours(psinstance_topology(stc->ps)));

  average_lossrate = finite(average_lossrate) ? average_lossrate : 0;        //start agressively, assuming 0 loss

  if (rand()/((double)RAND_MAX + 1) < 1 * average_lossrate ) {

    return;

  }

  send_ack(stc, from, trans_id);        //send explicit ack

}

void received_chunk(struct streaming_context * stc, struct nodeID *from, const uint8_t *buff, int len)

{

  int res;

  static struct chunk c;

  struct peer *p;

  static int bcast_cnt;

  uint16_t transid;

  res = parseChunkMsg(buff + 1, len - 1, &c, &transid);

  if (res > 0) {

                if (stc->chunk_loss_interval && c.id % stc->chunk_loss_interval == 0) {

                        fprintf(stderr,"[NOISE] Chunk %d discarded >:)\n",c.id);

                        free(c.data);

                        free(c.attributes);

                        return;

                }

    chunk_attributes_update_received(&c);

    chunk_unlock(stc->ch_locks, c.id);

    dprintf("Received chunk %d from peer: %s\n", c.id, nodeid_static_str(from));

#ifdef LOG_CHUNK

    log_chunk(from,psinstance_nodeid(stc->ps),&c,"RECEIVED");

#endif

//{fprintf(stderr, "TEO: Peer %s received chunk %d from peer: %s at: %"PRIu64" hopcount: %i Size: %d bytes\n", node_addr_tr(get_my_addr()),c.id, node_addr_tr(from), gettimeofday_in_us(), chunk_get_hopcount(&c), c.size);}

    output_deliver(psinstance_output(stc->ps), &c);

    res = cb_add_chunk(stc->cb, &c);

    reg_chunk_receive(psinstance_measures(stc->ps),c.id, c.timestamp, chunk_get_hopcount(&c), res==E_CB_OLD, res==E_CB_DUPLICATE);

    cb_print(stc);

    if (res < 0) {

      dprintf("\tchunk too old, buffer full with newer chunks\n");

#ifdef LOG_CHUNK

      log_chunk_error(from,psinstance_nodeid(stc->ps),&c,res); //{fprintf(stderr, "TEO: Received chunk: %d too old (buffer full with newer chunks) from peer: %s at: %"PRIu64"\n", c.id, node_addr_tr(from), gettimeofday_in_us());}

#endif

      free(c.data);

      free(c.attributes);

    }

    p = nodeid_to_peer(psinstance_topology(stc->ps), from, stc->neigh_on_chunk_recv);

    if (p) {        //now we have it almost sure

      chunkID_set_add_chunk(p->bmap,c.id);        //don't send it back

      gettimeofday(&p->bmap_timestamp, NULL);

    }

    ack_chunk(stc, &c, from, transid);        //send explicit ack

    if (stc->bcast_after_receive_every && bcast_cnt % stc->bcast_after_receive_every == 0) {

       bcast_bmap(stc);

    }

  } else {

    fprintf(stderr,"\tError: can't decode chunk!\n");

  }

}

struct chunk *generated_chunk(struct streaming_context * stc, suseconds_t *delta)

{

  struct chunk *c;

  c = malloc(sizeof(struct chunk));

  if (!c) {

    fprintf(stderr, "Memory allocation error!\n");

    return NULL;

  }

  memset(c, 0, sizeof(struct chunk));

  *delta = (suseconds_t)input_get(stc->input, c);

  if (*delta < 0) {

    fprintf(stderr, "Error in input!\n");

    exit(-1);

  }

  if (c->data == NULL) {

    free(c);

    return NULL;

  }

  dprintf("Generated chunk %d of %d bytes\n",c->id, c->size);

  chunk_attributes_fill(c);

  return c;

}

int add_chunk(struct streaming_context * stc, struct chunk *c)

{

  int res;

  if (stc && c && stc->cb)

  {

          res = cb_add_chunk(stc->cb, c);

          if (res < 0) {

            free(c->data);

            free(c->attributes);

            free(c);

            return 0;

          }

         // free(c);

          return 1;

  }

  return 0;

}

uint64_t get_chunk_timestamp(const struct streaming_context * stc, int cid){

  const struct chunk *c = cb_get_chunk(stc->cb, cid);

  if (!c) return 0;

  return c->timestamp;

}

void print_chunkID_set(struct chunkID_set *cset)

{

        uint32_t * ptr = (uint32_t *) cset;

        uint32_t n_elements,i;

        int * data = (int *) &(ptr[3]);

        fprintf(stderr,"[DEBUG] Chunk ID set type: %d\n",ptr[0]);

        fprintf(stderr,"[DEBUG] Chunk ID set size: %d\n",ptr[1]);

        n_elements = ptr[2];

        fprintf(stderr,"[DEBUG] Chunk ID n_elements: %d\n",n_elements);

        fprintf(stderr,"[DEBUG] Chunk ID elements: [");

        for (i=0;i<n_elements;i++)

                fprintf(stderr,".%d.",data[i]);

        fprintf(stderr,"]\n");

}

/**

 *example function to filter chunks based on whether a given peer needs them.

 *

 * Looks at buffermap information received about the given peer.

 */

int needs_old(const struct streaming_context * stc, struct peer *n, int cid){

  struct peer * p = n;

  if (stc->CB_SIZE_TIME < CB_SIZE_TIME_UNLIMITED) {

    uint64_t ts;

    ts = get_chunk_timestamp(stc, cid);

    if (ts && (ts < gettimeofday_in_us() - stc->CB_SIZE_TIME)) {        //if we don't know the timestamp, we accept

      return 0;

    }

  }

  //dprintf("\t%s needs c%d ? :",node_addr_tr(p->id),c->id);

  if (! p->bmap) { // this will never happen since the pset module initializes bmap

    //dprintf("no bmap\n");

    return 1;        // if we have no bmap information, we assume it needs the chunk (aggressive behaviour!)

  }

//        fprintf(stderr,"[DEBUG] Evaluating Peer %s, CB_SIZE: %d\n",node_addr_tr(n->id),p->cb_size); // DEBUG

//        print_chunkID_set(p->bmap);                                                                                                                                                                        // DEBUG

  return _needs(stc, p->bmap, p->cb_size, cid);

}

/**

 * Function checking if chunkID_set cset may need chunk with id cid

 * @cset: target cset

 * @cb_size: maximum allowed numer of chunks. In the case of offer it indicates

 *         the maximum capacity in of the receiving peer (so it's 0 for the source)

 * @cid: target chunk identifier

 */

int _needs(const struct streaming_context * stc, struct chunkID_set *cset, int cb_size, int cid){

  if (cb_size == 0) { //if it declared it does not needs chunks

    return 0;

  }

  if (stc->CB_SIZE_TIME < CB_SIZE_TIME_UNLIMITED) {

    uint64_t ts;

    ts = get_chunk_timestamp(stc, cid);

    if (ts && (ts < gettimeofday_in_us() - stc->CB_SIZE_TIME)) {        //if we don't know the timestamp, we accept

      return 0;

    }

  }

  if (chunkID_set_check(cset,cid) < 0) { //it might need the chunk

    int missing, min;

    //@TODO: add some bmap_timestamp based logic

    if (chunkID_set_size(cset) == 0) {

      //dprintf("bmap empty\n");

      return 1;        // if the bmap seems empty, it needs the chunk

    }

    missing = stc->cb_size - chunkID_set_size(cset);

    missing = missing < 0 ? 0 : missing;

    min = chunkID_set_get_earliest(cset);

      //dprintf("%s ... cid(%d) >= min(%d) - missing(%d) ?\n",(cid >= min - missing)?"YES":"NO",cid, min, missing);

    return (cid >= min - missing);

  }

  //dprintf("has it\n");

  return 0;

}

int needs(struct peer *p, int cid)

{

        int min;

        if (p->cb_size == 0) // it does not have capacity

                return 0;

        if (chunkID_set_check(p->bmap,cid) < 0)  // not in bmap

        {

                if(p->cb_size > chunkID_set_size(p->bmap)) // it has room for chunks anyway

                {

                        min = chunkID_set_get_earliest(p->bmap) - p->cb_size + chunkID_set_size(p->bmap);

                        min = min < 0 ? 0 : min;

                        if (cid >= min)

                                return 1;

                }

                if((int)chunkID_set_get_earliest(p->bmap) < cid)  // our is reasonably new

                        return 1;

        }

        return 0;

}

double peerWeightReceivedfrom(struct peer **n){

  struct peer * p = *n;

  return timerisset(&p->bmap_timestamp) ? 1 : 0.1;

}

double peerWeightUniform(struct peer **n){

  return 1;

}

double peerWeightLoss(struct peer **n){

  return 1;

}

//double peerWeightRtt(struct peer **n){

//#ifdef MONL

//  double rtt = get_rtt((*n)->id);

//  //dprintf("RTT to %s: %f\n", node_addr_tr(p->id), rtt);

//  return finite(rtt) ? 1 / (rtt + 0.005) : 1 / 1;

//#else

//  return 1;

//#endif

//}

//ordering function for ELp peer selection, chunk ID based

//can't be used as weight

//double peerScoreELpID(struct nodeID **n){

//  struct chunkID_set *bmap;

//  int latest;

//  struct peer * p = nodeid_to_peer(*n, 0);

//  if (!p) return 0;

//

//  bmap = p->bmap;

//  if (!bmap) return 0;

//  latest = chunkID_set_get_latest(bmap);

//  if (latest == INT_MIN) return 0;

//

//  return -latest;

//}

double chunkScoreChunkID(int *cid){

  return (double) *cid;

}

uint64_t get_chunk_deadline(const struct streaming_context * stc, int cid){

  const struct chunk_attributes * ca;

  const struct chunk *c;

  c = cb_get_chunk(stc->cb, cid);

  if (!c) return 0;

  if (!c->attributes || c->attributes_size != sizeof(struct chunk_attributes)) {

    fprintf(stderr,"Warning, chunk %d with strange attributes block\n", c->id);

    return 0;

  }

  ca = (struct chunk_attributes *) c->attributes;

  return ca->deadline;

}

//double chunkScoreDL(int *cid){

//  return - (double)get_chunk_deadline(*cid);

//}

//double chunkScoreTimestamp(int *cid){

//  return (double) get_chunk_timestamp(*cid);

//}

void send_accepted_chunks(const struct streaming_context * stc, struct nodeID *toid, struct chunkID_set *cset_acc, int max_deliver, uint16_t trans_id){

  int i, d, cset_acc_size, res;

  struct peer *to = nodeid_to_peer(psinstance_topology(stc->ps), toid, 0);

  transaction_reg_accept(stc->transactions, trans_id, toid);

  cset_acc_size = chunkID_set_size(cset_acc);

  reg_offer_accept_out(psinstance_measures(stc->ps),cset_acc_size > 0 ? 1 : 0);        //this only works if accepts are sent back even if 0 is accepted

  for (i = 0, d=0; i < cset_acc_size && d < max_deliver; i++) {

    const struct chunk *c;

    int chunkid = chunkID_set_get_chunk(cset_acc, i);

    c = cb_get_chunk(stc->cb, chunkid);

    if (!c) {        // we should have the chunk

      dprintf("%s asked for chunk %d we do not own anymore\n", nodeid_static_str(toid), chunkid);

      continue;

    }

    if (!to || needs(to, chunkid)) {        //he should not have it. Although the "accept" should have been an answer to our "offer", we do some verification

      chunk_attributes_update_sending(c);

      res = sendChunk(psinstance_nodeid(stc->ps),toid, c, trans_id);

      if (res >= 0) {

        if(to) chunkID_set_add_chunk(to->bmap, c->id); //don't send twice ... assuming that it will actually arrive

        d++;

        reg_chunk_send(psinstance_measures(stc->ps),c->id);

#ifdef LOG_CHUNK

              log_chunk(psinstance_nodeid(stc->ps), toid,c, "SENT_ACCEPTED");

#endif

        //{fprintf(stderr, "TEO: Sending chunk %d to peer: %s at: %"PRIu64" Result: %d Size: %d bytes\n", c->id, node_addr_tr(toid), gettimeofday_in_us(), res, c->size);}

      } else {

        fprintf(stderr,"ERROR sending chunk %d\n",c->id);

      }

    }

  }

}

int offer_peer_count(const struct streaming_context * stc)

{

  return psinstance_num_offers(stc->ps);

}

int offer_max_deliver(const struct streaming_context * stc, const struct nodeID *n)

{

  return psinstance_chunks_per_offer(stc->ps);

}

////get the rtt. Currenly only MONL version is supported

//static double get_rtt_of(struct nodeID* n){

//#ifdef MONL

//  return get_rtt(n);

//#else

//  return NAN;

//#endif

//}

#define DEFAULT_RTT_ESTIMATE 0.5

struct chunkID_set *compose_offer_cset(const struct streaming_context * stc, const struct peer *p)

{

  int num_chunks, j;

  uint64_t smallest_ts; //, largest_ts;

  double dt;

  struct chunkID_set *my_bmap = chunkID_set_init("type=bitmap");

  struct chunk *chunks = cb_get_chunks(stc->cb, &num_chunks);

  dt = DEFAULT_RTT_ESTIMATE;

  dt *= 1e6;        //convert to usec

  smallest_ts = chunks[0].timestamp;

//  largest_ts = chunks[num_chunks-1].timestamp;

  //add chunks in latest...earliest order

  if (psinstance_is_source(stc->ps)) {

    j = (num_chunks-1) * 3/4;        //do not send offers for the latest chunks from the source

  } else {

    j = num_chunks-1;

  }

  for(; j>=0; j--) {

    if (chunks[j].timestamp > smallest_ts + dt)

    chunkID_set_add_chunk(my_bmap, chunks[j].id);

  }

  return my_bmap;

}

void send_offer(struct streaming_context * stc)

{

  struct chunk *buff;

  size_t size=0,  i, n;

  struct peer **neighbours;

  struct peerset *pset;

  pset = topology_get_neighbours(psinstance_topology(stc->ps));

  n = peerset_size(pset);

  neighbours = peerset_get_peers(pset);

  // dprintf("Send Offer: %lu neighbours\n", n);

  if (n == 0) return;

  buff = cb_get_chunks(stc->cb, (int *)&size);

  if (size == 0) return;

    size_t selectedpeers_len = offer_peer_count(stc);

    int chunkids[size];

    struct peer *nodeids[n];

    struct peer *selectedpeers[selectedpeers_len];

    //reduce load a little bit if there are losses on the path from this guy

    double average_lossrate = get_average_lossrate_pset(pset);

    average_lossrate = finite(average_lossrate) ? average_lossrate : 0;        //start agressively, assuming 0 loss

    if (rand()/((double)RAND_MAX + 1) < 10 * average_lossrate ) {

      return;

    }

    for (i = 0;i < size; i++) chunkids[size - 1 - i] = (buff+i)->id;

    for (i = 0; i<n; i++) nodeids[i] = neighbours[i];

    selectPeersForChunks(SCHED_WEIGHTING, nodeids, n, chunkids, size, selectedpeers, &selectedpeers_len, SCHED_NEEDS, SCHED_PEER);

    for (i=0; i<selectedpeers_len ; i++){

      int transid = transaction_create(&(stc->transactions), selectedpeers[i]->id);

      int max_deliver = offer_max_deliver(stc, selectedpeers[i]->id);

      struct chunkID_set *offer_cset = compose_offer_cset(stc, selectedpeers[i]);

      dprintf("\t sending offer(%d) to %s, cb_size: %d\n", transid, nodeid_static_str(selectedpeers[i]->id), selectedpeers[i]->cb_size);

      offerChunks(psinstance_nodeid(stc->ps),selectedpeers[i]->id, offer_cset, max_deliver, transid++);

#ifdef LOG_SIGNAL

                        log_signal(psinstance_nodeid(stc->ps),selectedpeers[i]->id,chunkID_set_size(offer_cset),transid,sig_offer,"SENT");

#endif

      chunkID_set_free(offer_cset);

    }

}

void log_chunk_error(const struct nodeID *from,const struct nodeID *to,const struct chunk *c,int error)

{

        switch (error) {

                case E_CB_OLD:

                log_chunk(from,to,c,"TOO_OLD");

                break;

                case E_CB_DUPLICATE:

                log_chunk(from,to,c,"DUPLICATED");

                break;

                default:

                log_chunk(from,to,c,"ERROR");

        } 

}

void log_neighbourhood(const struct streaming_context * stc)

{

  struct peerset * pset;

  const struct peer * p;

  int psetsize,i;

  uint64_t now;

  char me[NODE_STR_LENGTH];

  node_addr(psinstance_nodeid(stc->ps), me, NODE_STR_LENGTH);

  pset = topology_get_neighbours(psinstance_topology(stc->ps));

  psetsize = peerset_size(pset);

  now = gettimeofday_in_us();

  peerset_for_each(pset,p,i)

    fprintf(stderr,"[NEIGHBOURHOOD],%"PRIu64",%s,%s,%d\n",now,me,nodeid_static_str(p->id),psetsize);

}

void log_chunk(const struct nodeID *from,const struct nodeID *to,const struct chunk *c,const char * note)

{

        // semantic: [CHUNK_LOG],log_date,sender,receiver,id,size(bytes),chunk_timestamp,hopcount,notes

        char sndr[NODE_STR_LENGTH],rcvr[NODE_STR_LENGTH];

        node_addr(from,sndr,NODE_STR_LENGTH);

        node_addr(to,rcvr,NODE_STR_LENGTH);

        fprintf(stderr,"[CHUNK_LOG],%"PRIu64",%s,%s,%d,%d,%"PRIu64",%i,%s\n",gettimeofday_in_us(),sndr,rcvr,c->id,c->size,c->timestamp,chunk_get_hopcount(c),note);

}

void log_signal(const struct nodeID *fromid,const struct nodeID *toid,const int cidset_size,uint16_t trans_id,enum signaling_type type,const char *flag)

{

        char typestr[24];

        char sndr[NODE_STR_LENGTH],rcvr[NODE_STR_LENGTH];

        node_addr(fromid,sndr,NODE_STR_LENGTH);

        node_addr(toid,rcvr,NODE_STR_LENGTH);

        switch (type)

        {

                case sig_offer:

                        sprintf(typestr,"%s","OFFER_SIG");

                        break;

                case sig_accept:

                        sprintf(typestr,"%s","ACCEPT_SIG");

                        break;

                case sig_request:

                        sprintf(typestr,"%s","REQUEST_SIG");

                        break;

                case sig_deliver:

                        sprintf(typestr,"%s","DELIVER_SIG");

                        break;

                case sig_send_buffermap:

                        sprintf(typestr,"%s","SEND_BMAP_SIG");

                        break;

                case sig_request_buffermap:

                        sprintf(typestr,"%s","REQUEST_BMAP_SIG");

                        break;

                case sig_ack:

                        sprintf(typestr,"%s","CHUNK_ACK_SIG");

                        break;

                default:

                        sprintf(typestr,"%s","UNKNOWN_SIG");

        }

        fprintf(stderr,"[OFFER_LOG],%s,%s,%d,%s,%s\n",sndr,rcvr,trans_id,typestr,flag);

}

int peer_chunk_dispatch(struct streaming_context * stc, const struct PeerChunk  *pairs,const size_t num_pairs)

{

        int transid, res,success = 0;

        size_t i;

        const struct peer * target_peer;

        const struct chunk * target_chunk;

        for (i=0; i<num_pairs ; i++){

                target_peer = pairs[i].peer;

                target_chunk = cb_get_chunk(stc->cb, pairs[i].chunk);

                if (stc->send_bmap_before_push) {

                        send_bmap(stc, target_peer->id);

                }

                chunk_attributes_update_sending(target_chunk);

                transid = transaction_create(&(stc->transactions), target_peer->id);

                res = sendChunk(psinstance_nodeid(stc->ps),target_peer->id, target_chunk, transid);        //we use transactions in order to register acks for push

                if (res>=0) {

#ifdef LOG_CHUNK

                        log_chunk(psinstance_nodeid(stc->ps), target_peer->id, target_chunk,"SENT");

#endif

//                        chunkID_set_add_chunk((target_peer)->bmap,target_chunk->id); //don't send twice ... assuming that it will actually arrive

                        reg_chunk_send(psinstance_measures(stc->ps),target_chunk->id);

                        success++;

                } else {

                        fprintf(stderr,"ERROR sending chunk %d\n",target_chunk->id);

                }

        }

        return success;

}

int inject_chunk(struct streaming_context * stc, const struct chunk * target_chunk,const int multiplicity)

/*injects a specific chunk in the overlay and return the number of injected copies*/

{

        struct peerset *pset;

        struct peer ** peers, ** dst_peers;

        int peers_num;

        double (* peer_evaluation) (struct peer **n);

        size_t i, selectedpairs_len = multiplicity;

        struct PeerChunk  * selectedpairs;

        pset = topology_get_neighbours(psinstance_topology(stc->ps));

        peers_num = peerset_size(pset);

        peers = peerset_get_peers(pset);

        peer_evaluation = SCHED_PEER;

  //SCHED_TYPE(SCHED_WEIGHTING, peers, peers_num, &(target_chunk->id), 1, selectedpairs, &selectedpairs_len, SCHED_NEEDS, peer_evaluation, SCHED_CHUNK);

         dst_peers = (struct peer **) malloc(sizeof(struct peer* ) *  multiplicity);

         selectPeersForChunks(SCHED_WEIGHTING, peers, peers_num, (int *)&(target_chunk->id) , 1, dst_peers, &selectedpairs_len, NULL, peer_evaluation);

        selectedpairs = (struct PeerChunk *)  malloc(sizeof(struct PeerChunk) * selectedpairs_len);

        for ( i=0; i<selectedpairs_len; i++)

        {

                selectedpairs[i].peer = dst_peers[i];

                selectedpairs[i].chunk = target_chunk->id;

        }

        peer_chunk_dispatch(stc, selectedpairs,selectedpairs_len);

        free(selectedpairs);

        free(dst_peers);

        return selectedpairs_len;

}

void send_chunk(struct streaming_context * stc)

{

  struct chunk *buff;

  int size, res, i, n;

  struct peer **neighbours;

  struct peerset *pset;

  pset = topology_get_neighbours(psinstance_topology(stc->ps));

  n = peerset_size(pset);

  neighbours = peerset_get_peers(pset);

  dprintf("Send Chunk: %d neighbours\n", n);

  if (n == 0) return;

  buff = cb_get_chunks(stc->cb, &size);

  dprintf("\t %d chunks in buffer...\n", size);

  if (size == 0) return;

  /************ STUPID DUMB SCHEDULING ****************/

  //target = n * (rand() / (RAND_MAX + 1.0)); /*0..n-1*/

  //c = size * (rand() / (RAND_MAX + 1.0)); /*0..size-1*/

  /************ /STUPID DUMB SCHEDULING ****************/

  /************ USE SCHEDULER ****************/

  {

    size_t selectedpairs_len = 1;

    int chunkids[size];

                int transid;

    struct peer *nodeids[n];

    struct PeerChunk selectedpairs[1];

    for (i = 0;i < size; i++) chunkids[size - 1 - i] = (buff+i)->id;

    for (i = 0; i<n; i++) nodeids[i] = neighbours[i];

            SCHED_TYPE(SCHED_WEIGHTING, nodeids, n, chunkids, 1, selectedpairs, &selectedpairs_len, SCHED_NEEDS, SCHED_PEER, SCHED_CHUNK);

  /************ /USE SCHEDULER ****************/

    for (i=0; i<(int)selectedpairs_len ; i++){

      struct peer *p = selectedpairs[i].peer;

      const struct chunk *c = cb_get_chunk(stc->cb, selectedpairs[i].chunk);

      dprintf("\t sending chunk[%d] to ", c->id);

      dprintf("%s\n", nodeid_static_str(p->id));

      if (stc->send_bmap_before_push) {

        send_bmap(stc, p->id);

      }

      chunk_attributes_update_sending(c);

      transid = transaction_create(&(stc->transactions), p->id);

      res = sendChunk(psinstance_nodeid(stc->ps),p->id, c, transid);        //we use transactions in order to register acks for push

//      res = sendChunk(p->id, c, 0);        //we do not use transactions in pure push

      dprintf("\tResult: %d\n", res);

      if (res>=0) {

#ifdef LOG_CHUNK

              log_chunk(psinstance_nodeid(stc->ps),p->id,c,"SENT");

#endif

//{fprintf(stderr, "TEO: Sending chunk %d to peer: %s at: %"PRIu64" Result: %d Size: %d bytes\n", c->id, node_addr_tr(p->id), gettimeofday_in_us(), res, c->size);}

        chunkID_set_add_chunk(p->bmap,c->id); //don't send twice ... assuming that it will actually arrive

        reg_chunk_send(psinstance_measures(stc->ps),c->id);

      } else {

        fprintf(stderr,"ERROR sending chunk %d\n",c->id);

      }

    }

  }

}