X-Git-Url: http://p2p-next.cs.pub.ro/gitweb/?a=blobdiff_plain;f=src%2Flibswift%2Fsendrecv.cpp;fp=src%2Flibswift%2Fsendrecv.cpp;h=e64d3eea324f9812f5bf9f8c4b15d9e1b7533ff6;hb=45963a7511531cd1656ad5d3847d2dafd015c54d;hp=0000000000000000000000000000000000000000;hpb=d069796805ad79542fd7e4406d1e9c6d2d8c2ef7;p=swifty.git

diff --git a/src/libswift/sendrecv.cpp b/src/libswift/sendrecv.cpp
new file mode 100644
index 0000000..e64d3ee
--- /dev/null
+++ b/src/libswift/sendrecv.cpp
@@ -0,0 +1,1089 @@
+/*
+ *  sendrecv.cpp
+ *  most of the swift's state machine
+ *
+ *  Created by Victor Grishchenko on 3/6/09.
+ *  Copyright 2009-2012 TECHNISCHE UNIVERSITEIT DELFT. All rights reserved.
+ *
+ */
+#include "bin_utils.h"
+#include "swift.h"
+#include <algorithm>  // kill it
+#include <cassert>
+#include <math.h>
+#include <cfloat>
+#include "compat.h"
+
+using namespace swift;
+using namespace std;
+
+struct event_base *Channel::evbase;
+struct event Channel::evrecv;
+
+#define DEBUGTRAFFIC 	0
+
+/** Arno: Victor's design allows a sender to choose some data to push to
+ * a receiver, if that receiver is not HINTing at data. Should be disabled
+ * when the receiver has a download rate limit.
+ */
+#define ENABLE_SENDERSIZE_PUSH 0
+
+
+/** Arno, 2011-11-24: When rate limit is on and the download is in progress
+ * we send HINTs for 2 chunks at the moment. This constant can be used to
+ * get greater granularity. Set to 0 for original behaviour.
+ */
+#define HINT_GRANULARITY	16 // chunks
+
+/*
+ TODO  25 Oct 18:55
+ - range: ALL
+ - randomized testing of advanced ops (new testcase)
+ */
+
+void    Channel::AddPeakHashes (struct evbuffer *evb) {
+    for(int i=0; i<file().peak_count(); i++) {
+        bin_t peak = file().peak(i);
+        evbuffer_add_8(evb, SWIFT_HASH);
+        evbuffer_add_32be(evb, bin_toUInt32(peak));
+        evbuffer_add_hash(evb, file().peak_hash(i));
+        char bin_name_buf[32];
+        dprintf("%s #%u +phash %s\n",tintstr(),id_,peak.str(bin_name_buf));
+    }
+}
+
+
+void    Channel::AddUncleHashes (struct evbuffer *evb, bin_t pos) {
+
+    char bin_name_buf2[32];
+    dprintf("%s #%u +uncle hash for %s\n",tintstr(),id_,pos.str(bin_name_buf2));
+
+    bin_t peak = file().peak_for(pos);
+    while (pos!=peak && ((NOW&3)==3 || !pos.parent().contains(data_out_cap_)) &&
+            ack_in_.is_empty(pos.parent()) ) {
+        bin_t uncle = pos.sibling();
+        evbuffer_add_8(evb, SWIFT_HASH);
+        evbuffer_add_32be(evb, bin_toUInt32(uncle));
+        evbuffer_add_hash(evb,  file().hash(uncle) );
+        char bin_name_buf[32];
+        dprintf("%s #%u +hash %s\n",tintstr(),id_,uncle.str(bin_name_buf));
+        pos = pos.parent();
+    }
+}
+
+
+bin_t           Channel::ImposeHint () {
+    uint64_t twist = peer_channel_id_;  // got no hints, send something randomly
+
+    twist &= file().peak(0).toUInt(); // FIXME may make it semi-seq here
+
+    bin_t my_pick = binmap_t::find_complement(ack_in_, file().ack_out(), twist);
+
+    my_pick.to_twisted(twist);
+    while (my_pick.base_length()>max(1,(int)cwnd_))
+        my_pick = my_pick.left();
+
+    return my_pick.twisted(twist);
+}
+
+
+bin_t        Channel::DequeueHint (bool *retransmitptr) {
+    bin_t send = bin_t::NONE;
+
+    // Arno, 2012-01-23: Extra protection against channel loss, don't send DATA
+    if (last_recv_time_ < NOW-(3*TINT_SEC))
+    	return bin_t::NONE;
+
+    // Arno, 2012-01-18: Reenable Victor's retransmit
+    if (!data_out_tmo_.empty())
+    {
+        tintbin tb = data_out_tmo_.front();
+        send = tb.bin;
+        data_out_tmo_.pop_front();  
+        *retransmitptr = true;
+    }
+    else
+        *retransmitptr = false;
+
+    if (ENABLE_SENDERSIZE_PUSH && send.is_none() && hint_in_.empty() && last_recv_time_>NOW-rtt_avg_-TINT_SEC) {
+        bin_t my_pick = ImposeHint(); // FIXME move to the loop
+        if (!my_pick.is_none()) {
+            hint_in_.push_back(my_pick);
+            char bin_name_buf[32];
+            dprintf("%s #%u *hint %s\n",tintstr(),id_,my_pick.str(bin_name_buf));
+        }
+    }
+    
+    while (!hint_in_.empty() && send.is_none()) {
+        bin_t hint = hint_in_.front().bin;
+        tint time = hint_in_.front().time;
+        hint_in_.pop_front();
+        while (!hint.is_base()) { // FIXME optimize; possible attack
+            hint_in_.push_front(tintbin(time,hint.right()));
+            hint = hint.left();
+        }
+        //if (time < NOW-TINT_SEC*3/2 )
+        //    continue;  bad idea
+        if (!ack_in_.is_filled(hint))
+            send = hint;
+    }
+    uint64_t mass = 0;
+    // Arno, 2012-03-09: Is mucho expensive on busy server.
+    //for(int i=0; i<hint_in_.size(); i++)
+    //    mass += hint_in_[i].bin.base_length();
+    char bin_name_buf[32];
+    dprintf("%s #%u dequeued %s [%lli]\n",tintstr(),id_,send.str(bin_name_buf),mass);
+    return send;
+}
+
+
+void    Channel::AddHandshake (struct evbuffer *evb) {
+    if (!peer_channel_id_) { // initiating
+        evbuffer_add_8(evb, SWIFT_HASH);
+        evbuffer_add_32be(evb, bin_toUInt32(bin_t::ALL));
+        evbuffer_add_hash(evb, file().root_hash());
+        dprintf("%s #%u +hash ALL %s\n",
+                tintstr(),id_,file().root_hash().hex().c_str());
+    }
+    evbuffer_add_8(evb, SWIFT_HANDSHAKE);
+    int encoded = -1;
+    if (send_control_==CLOSE_CONTROL) {
+    	encoded = 0;
+    }
+    else
+    	encoded = EncodeID(id_);
+    evbuffer_add_32be(evb, encoded);
+    dprintf("%s #%u +hs %x\n",tintstr(),id_,encoded);
+    have_out_.clear();
+}
+
+
+void    Channel::Send () {
+
+	dprintf("%s #%u Send called \n",tintstr(),id_);
+
+    struct evbuffer *evb = evbuffer_new();
+    evbuffer_add_32be(evb, peer_channel_id_);
+    bin_t data = bin_t::NONE;
+    int evbnonadplen = 0;
+    if ( is_established() ) {
+    	if (send_control_!=CLOSE_CONTROL) {
+			// FIXME: seeder check
+			AddHave(evb);
+			AddAck(evb);
+			if (!file().is_complete()) {
+				AddHint(evb);
+				/* Gertjan fix: 7aeea65f3efbb9013f601b22a57ee4a423f1a94d
+				"Only call Reschedule for 'reverse PEX' if the channel is in keep-alive mode"
+				 */
+				AddPexReq(evb);
+			}
+			AddPex(evb);
+			TimeoutDataOut();
+			data = AddData(evb);
+    	} else {
+    		// Arno: send explicit close
+    		AddHandshake(evb);
+    	}
+    } else {
+        AddHandshake(evb);
+        AddHave(evb); // Arno, 2011-10-28: from AddHandShake. Why double?
+        AddHave(evb);
+        AddAck(evb);
+    }
+
+    lastsendwaskeepalive_ = (evbuffer_get_length(evb) == 4);
+
+    if (evbuffer_get_length(evb)==4) {// only the channel id; bare keep-alive
+        data = bin_t::ALL;
+    }
+    dprintf("%s #%u sent %ib %s:%x\n",
+            tintstr(),id_,(int)evbuffer_get_length(evb),peer().str(),
+            peer_channel_id_);
+    int r = SendTo(socket_,peer(),evb);
+    if (r==-1)
+        print_error("can't send datagram");
+    else
+    	raw_bytes_up_ += r;
+    last_send_time_ = NOW;
+    sent_since_recv_++;
+    dgrams_sent_++;
+    evbuffer_free(evb);
+    Reschedule();
+}
+
+void    Channel::AddHint (struct evbuffer *evb) {
+
+	// RATELIMIT
+	// Policy is to not send hints when we are above speed limit
+	if (transfer().GetCurrentSpeed(DDIR_DOWNLOAD) > transfer().GetMaxSpeed(DDIR_DOWNLOAD)) {
+		if (DEBUGTRAFFIC)
+			fprintf(stderr,"hint: forbidden#");
+		return;
+	}
+
+
+	// 1. Calc max of what we are allowed to request, uncongested bandwidth wise
+    tint plan_for = max(TINT_SEC,rtt_avg_*4);
+
+    tint timed_out = NOW - plan_for*2;
+    while ( !hint_out_.empty() && hint_out_.front().time < timed_out ) {
+        hint_out_size_ -= hint_out_.front().bin.base_length();
+        hint_out_.pop_front();
+    }
+
+    int first_plan_pck = max ( (tint)1, plan_for / dip_avg_ );
+
+    // Riccardo, 2012-04-04: Actually allowed is max minus what we already asked for
+    int queue_allowed_hints = max(0,first_plan_pck-(int)hint_out_size_);
+
+
+    // RATELIMIT
+    // 2. Calc max of what is allowed by the rate limiter
+    int rate_allowed_hints = LONG_MAX;
+    if (transfer().GetMaxSpeed(DDIR_DOWNLOAD) < DBL_MAX)
+    {
+		uint64_t rough_global_hint_out_size = 0; // rough estimate, as hint_out_ clean up is not done for all channels
+		std::set<Channel *>::iterator iter;
+		for (iter=transfer().mychannels_.begin(); iter!=transfer().mychannels_.end(); iter++)
+		{
+			Channel *c = *iter;
+			if (c != NULL)
+				rough_global_hint_out_size += c->hint_out_size_;
+		}
+
+		// Policy: this channel is allowed to hint at the limit - global_hinted_at
+		// Handle MaxSpeed = unlimited
+		double rate_hints_limit_float = transfer().GetMaxSpeed(DDIR_DOWNLOAD)/((double)file().chunk_size());
+
+		int rate_hints_limit = (int)min((double)LONG_MAX,rate_hints_limit_float);
+
+		// Actually allowed is max minus what we already asked for, globally (=all channels)
+		rate_allowed_hints = max(0,rate_hints_limit-(int)rough_global_hint_out_size);
+    }
+
+    // 3. Take the smallest allowance from rate and queue limit
+    uint64_t plan_pck = (uint64_t)min(rate_allowed_hints,queue_allowed_hints);
+
+    // 4. Ask allowance in blocks of chunks to get pipelining going from serving peer.
+    if (hint_out_size_ == 0 || plan_pck > HINT_GRANULARITY)
+    {
+        bin_t hint = transfer().picker().Pick(ack_in_,plan_pck,NOW+plan_for*2);
+        if (!hint.is_none()) {
+        	if (DEBUGTRAFFIC)
+        	{
+        		char binstr[32];
+        		fprintf(stderr,"hint c%d: ask %s\n", id(), hint.str(binstr) );
+        	}
+            evbuffer_add_8(evb, SWIFT_HINT);
+            evbuffer_add_32be(evb, bin_toUInt32(hint));
+            char bin_name_buf[32];
+            dprintf("%s #%u +hint %s [%lli]\n",tintstr(),id_,hint.str(bin_name_buf),hint_out_size_);
+            hint_out_.push_back(hint);
+            hint_out_size_ += hint.base_length();
+            //fprintf(stderr,"send c%d: HINTLEN %i\n", id(), hint.base_length());
+            //fprintf(stderr,"HL %i ", hint.base_length());
+        }
+        else
+            dprintf("%s #%u Xhint\n",tintstr(),id_);
+
+    }
+}
+
+
+bin_t        Channel::AddData (struct evbuffer *evb) {
+	// RATELIMIT
+	if (transfer().GetCurrentSpeed(DDIR_UPLOAD) > transfer().GetMaxSpeed(DDIR_UPLOAD)) {
+		transfer().OnSendNoData();
+		return bin_t::NONE;
+	}
+
+    if (!file().size()) // know nothing
+        return bin_t::NONE;
+
+    bin_t tosend = bin_t::NONE;
+    bool isretransmit = false;
+    tint luft = send_interval_>>4; // may wake up a bit earlier
+    if (data_out_.size()<cwnd_ &&
+            last_data_out_time_+send_interval_<=NOW+luft) {
+        tosend = DequeueHint(&isretransmit);
+        if (tosend.is_none()) {
+            dprintf("%s #%u sendctrl no idea what data to send\n",tintstr(),id_);
+            if (send_control_!=KEEP_ALIVE_CONTROL && send_control_!=CLOSE_CONTROL)
+                SwitchSendControl(KEEP_ALIVE_CONTROL);
+        }
+    } else
+        dprintf("%s #%u sendctrl wait cwnd %f data_out %i next %s\n",
+                tintstr(),id_,cwnd_,(int)data_out_.size(),tintstr(last_data_out_time_+NOW-send_interval_));
+
+    if (tosend.is_none())// && (last_data_out_time_>NOW-TINT_SEC || data_out_.empty()))
+        return bin_t::NONE; // once in a while, empty data is sent just to check rtt FIXED
+
+    if (ack_in_.is_empty() && file().size())
+        AddPeakHashes(evb);
+
+    //NETWVSHASH
+    if (file().get_check_netwvshash())
+    	AddUncleHashes(evb,tosend);
+
+    if (!ack_in_.is_empty()) // TODO: cwnd_>1
+        data_out_cap_ = tosend;
+
+    // Arno, 2011-11-03: May happen when first data packet is sent to empty
+    // leech, then peak + uncle hashes may be so big that they don't fit in eth
+    // frame with DATA. Send 2 datagrams then, one with peaks so they have
+    // a better chance of arriving. Optimistic violation of atomic datagram
+    // principle.
+    if (file().chunk_size() == SWIFT_DEFAULT_CHUNK_SIZE && evbuffer_get_length(evb) > SWIFT_MAX_NONDATA_DGRAM_SIZE) {
+        dprintf("%s #%u fsent %ib %s:%x\n",
+                tintstr(),id_,(int)evbuffer_get_length(evb),peer().str(),
+                peer_channel_id_);
+    	int ret = Channel::SendTo(socket_,peer(),evb); // kind of fragmentation
+    	if (ret > 0)
+    		raw_bytes_up_ += ret;
+        evbuffer_add_32be(evb, peer_channel_id_);
+    }
+
+    if (file().chunk_size() != SWIFT_DEFAULT_CHUNK_SIZE && isretransmit) {
+    	/* FRAGRAND
+    	 * Arno, 2012-01-17: We observe strange behaviour when using
+    	 * fragmented UDP packets. When ULANC sends a specific datagram ("995"),
+    	 * the 2nd IP packet carrying it gets lost structurally. When
+    	 * downloading from the same asset hosted on a Linux 32-bit machine
+    	 * using a Win7 32-bit client (behind a NAT), one specific full
+    	 * datagram never gets delivered (6970 one before do). A workaround
+    	 * is to add some random data to the datagram. Hence we introduce
+    	 * the SWIFT_RANDOMIZE message, that is added to the datagram carrying
+    	 * the DATA on a retransmit.
+    	 */
+ 	     char binstr[32];
+         fprintf(stderr,"AddData: retransmit of randomized chunk %s\n",tosend.str(binstr) );
+         evbuffer_add_8(evb, SWIFT_RANDOMIZE);
+         evbuffer_add_32be(evb, (int)rand() );
+    }
+
+    evbuffer_add_8(evb, SWIFT_DATA);
+    evbuffer_add_32be(evb, bin_toUInt32(tosend));
+
+    struct evbuffer_iovec vec;
+    if (evbuffer_reserve_space(evb, file().chunk_size(), &vec, 1) < 0) {
+	print_error("error on evbuffer_reserve_space");
+	return bin_t::NONE;
+    }
+    size_t r = pread(file().file_descriptor(),(char *)vec.iov_base,
+		     file().chunk_size(),tosend.base_offset()*file().chunk_size());
+    // TODO: corrupted data, retries, caching
+    if (r<0) {
+        print_error("error on reading");
+        vec.iov_len = 0;
+        evbuffer_commit_space(evb, &vec, 1);
+        return bin_t::NONE;
+    }
+    // assert(dgram.space()>=r+4+1);
+    vec.iov_len = r;
+    if (evbuffer_commit_space(evb, &vec, 1) < 0) {
+        print_error("error on evbuffer_commit_space");
+        return bin_t::NONE;
+    }
+
+    last_data_out_time_ = NOW;
+    data_out_.push_back(tosend);
+    bytes_up_ += r;
+    global_bytes_up += r;
+
+    char bin_name_buf[32];
+    dprintf("%s #%u +data %s\n",tintstr(),id_,tosend.str(bin_name_buf));
+
+    // RATELIMIT
+    // ARNOSMPTODO: count overhead bytes too? Move to Send() then.
+	transfer_->OnSendData(file().chunk_size());
+
+    return tosend;
+}
+
+
+void    Channel::AddAck (struct evbuffer *evb) {
+    if (data_in_==tintbin())
+	//if (data_in_.bin==bin64_t::NONE)
+        return;
+    // sometimes, we send a HAVE (e.g. in case the peer did repetitive send)
+    evbuffer_add_8(evb, data_in_.time==TINT_NEVER?SWIFT_HAVE:SWIFT_ACK);
+    evbuffer_add_32be(evb, bin_toUInt32(data_in_.bin));
+    if (data_in_.time!=TINT_NEVER)
+        evbuffer_add_64be(evb, data_in_.time);
+
+
+	if (DEBUGTRAFFIC)
+		fprintf(stderr,"send c%d: ACK %i\n", id(), bin_toUInt32(data_in_.bin));
+
+    have_out_.set(data_in_.bin);
+    char bin_name_buf[32];
+    dprintf("%s #%u +ack %s %s\n",
+        tintstr(),id_,data_in_.bin.str(bin_name_buf),tintstr(data_in_.time));
+    if (data_in_.bin.layer()>2)
+        data_in_dbl_ = data_in_.bin;
+
+    //fprintf(stderr,"data_in_ c%d\n", id() );
+    data_in_ = tintbin();
+    //data_in_ = tintbin(NOW,bin64_t::NONE);
+}
+
+
+void    Channel::AddHave (struct evbuffer *evb) {
+    if (!data_in_dbl_.is_none()) { // TODO: do redundancy better
+        evbuffer_add_8(evb, SWIFT_HAVE);
+        evbuffer_add_32be(evb, bin_toUInt32(data_in_dbl_));
+        data_in_dbl_=bin_t::NONE;
+    }
+    if (DEBUGTRAFFIC)
+		fprintf(stderr,"send c%d: HAVE ",id() );
+    for(int count=0; count<4; count++) {
+        bin_t ack = binmap_t::find_complement(have_out_, file().ack_out(), 0); // FIXME: do rotating queue
+        if (ack.is_none())
+            break;
+        ack = file().ack_out().cover(ack);
+        have_out_.set(ack);
+        evbuffer_add_8(evb, SWIFT_HAVE);
+        evbuffer_add_32be(evb, bin_toUInt32(ack));
+
+    	if (DEBUGTRAFFIC)
+    		fprintf(stderr," %i", bin_toUInt32(ack));
+
+        char bin_name_buf[32];
+        dprintf("%s #%u +have %s\n",tintstr(),id_,ack.str(bin_name_buf));
+    }
+	if (DEBUGTRAFFIC)
+		fprintf(stderr,"\n");
+
+}
+
+
+void    Channel::Recv (struct evbuffer *evb) {
+    dprintf("%s #%u recvd %ib\n",tintstr(),id_,(int)evbuffer_get_length(evb)+4);
+    dgrams_rcvd_++;
+
+    lastrecvwaskeepalive_ = (evbuffer_get_length(evb) == 0);
+    if (lastrecvwaskeepalive_)
+    	// Update speed measurements such that they decrease when DL stops
+    	transfer().OnRecvData(0);
+
+    if (last_send_time_ && rtt_avg_==TINT_SEC && dev_avg_==0) {
+        rtt_avg_ = NOW - last_send_time_;
+        dev_avg_ = rtt_avg_;
+        dip_avg_ = rtt_avg_;
+        dprintf("%s #%u sendctrl rtt init %lli\n",tintstr(),id_,rtt_avg_);
+    }
+
+    bin_t data = evbuffer_get_length(evb) ? bin_t::NONE : bin_t::ALL;
+
+	if (DEBUGTRAFFIC)
+		fprintf(stderr,"recv c%d: size %d ", id(), evbuffer_get_length(evb));
+
+	while (evbuffer_get_length(evb)) {
+        uint8_t type = evbuffer_remove_8(evb);
+
+        if (DEBUGTRAFFIC)
+        	fprintf(stderr," %d", type);
+
+        switch (type) {
+            case SWIFT_HANDSHAKE: OnHandshake(evb); break;
+            case SWIFT_DATA:      data=OnData(evb); break;
+            case SWIFT_HAVE:      OnHave(evb); break;
+            case SWIFT_ACK:       OnAck(evb); break;
+            case SWIFT_HASH:      OnHash(evb); break;
+            case SWIFT_HINT:      OnHint(evb); break;
+            case SWIFT_PEX_ADD:   OnPex(evb); break;
+            case SWIFT_PEX_REQ:   OnPexReq(); break;
+            case SWIFT_RANDOMIZE: OnRandomize(evb); break; //FRAGRAND
+            default:
+                dprintf("%s #%u ?msg id unknown %i\n",tintstr(),id_,(int)type);
+                return;
+        }
+    }
+    if (DEBUGTRAFFIC)
+    {
+    	fprintf(stderr,"\n");
+    }
+
+
+    last_recv_time_ = NOW;
+    sent_since_recv_ = 0;
+    Reschedule();
+}
+
+/*
+ * Arno: FAXME: HASH+DATA should be handled as a transaction: only when the
+ * hashes check out should they be stored in the hashtree, otherwise revert.
+ */
+void    Channel::OnHash (struct evbuffer *evb) {
+	bin_t pos = bin_fromUInt32(evbuffer_remove_32be(evb));
+    Sha1Hash hash = evbuffer_remove_hash(evb);
+    file().OfferHash(pos,hash);
+    char bin_name_buf[32];
+    dprintf("%s #%u -hash %s\n",tintstr(),id_,pos.str(bin_name_buf));
+
+    //fprintf(stderr,"HASH %lli hex %s\n",pos.toUInt(), hash.hex().c_str() );
+}
+
+
+void    Channel::CleanHintOut (bin_t pos) {
+    int hi = 0;
+    while (hi<hint_out_.size() && !hint_out_[hi].bin.contains(pos))
+        hi++;
+    if (hi==hint_out_.size())
+        return; // something not hinted or hinted in far past
+    while (hi--) { // removing likely snubbed hints
+        hint_out_size_ -= hint_out_.front().bin.base_length();
+        hint_out_.pop_front();
+    }
+    while (hint_out_.front().bin!=pos) {
+        tintbin f = hint_out_.front();
+
+        assert (f.bin.contains(pos));
+
+        if (pos < f.bin) {
+            f.bin.to_left();
+        } else {
+            f.bin.to_right();
+        }
+
+        hint_out_.front().bin = f.bin.sibling();
+        hint_out_.push_front(f);
+    }
+    hint_out_.pop_front();
+    hint_out_size_--;
+}
+
+
+bin_t Channel::OnData (struct evbuffer *evb) {  // TODO: HAVE NONE for corrupted data
+
+	char bin_name_buf[32];
+	bin_t pos = bin_fromUInt32(evbuffer_remove_32be(evb));
+
+    // Arno: Assuming DATA last message in datagram
+    if (evbuffer_get_length(evb) > file().chunk_size()) {
+    	dprintf("%s #%u !data chunk size mismatch %s: exp %lu got " PRISIZET "\n",tintstr(),id_,pos.str(bin_name_buf), file().chunk_size(), evbuffer_get_length(evb));
+    	fprintf(stderr,"WARNING: chunk size mismatch: exp %lu got " PRISIZET "\n",file().chunk_size(), evbuffer_get_length(evb));
+    }
+
+    int length = (evbuffer_get_length(evb) < file().chunk_size()) ? evbuffer_get_length(evb) : file().chunk_size();
+    if (!file().ack_out().is_empty(pos)) {
+        // Arno, 2012-01-24: print message for duplicate
+        dprintf("%s #%u Ddata %s\n",tintstr(),id_,pos.str(bin_name_buf));
+        evbuffer_drain(evb, length);
+        data_in_ = tintbin(TINT_NEVER,transfer().ack_out().cover(pos));
+
+        // Arno, 2012-01-24: Make sure data interarrival periods don't get
+        // screwed up because of these (ignored) duplicates.
+        UpdateDIP(pos);
+        return bin_t::NONE;
+    }
+    uint8_t *data = evbuffer_pullup(evb, length);
+    data_in_ = tintbin(NOW,bin_t::NONE);
+    if (!file().OfferData(pos, (char*)data, length)) {
+    	evbuffer_drain(evb, length);
+        char bin_name_buf[32];
+        dprintf("%s #%u !data %s\n",tintstr(),id_,pos.str(bin_name_buf));
+        return bin_t::NONE;
+    }
+    evbuffer_drain(evb, length);
+    dprintf("%s #%u -data %s\n",tintstr(),id_,pos.str(bin_name_buf));
+
+    if (DEBUGTRAFFIC)
+    	fprintf(stderr,"$ ");
+
+    bin_t cover = transfer().ack_out().cover(pos);
+    for(int i=0; i<transfer().cb_installed; i++)
+        if (cover.layer()>=transfer().cb_agg[i])
+            transfer().callbacks[i](transfer().fd(),cover);  // FIXME
+    if (cover.layer() >= 5) // Arno: tested with 32K, presently = 2 ** 5 * chunk_size CHUNKSIZE
+    	transfer().OnRecvData( pow((double)2,(double)5)*((double)file().chunk_size()) );
+    data_in_.bin = pos;
+
+    UpdateDIP(pos);
+    CleanHintOut(pos);
+    bytes_down_ += length;
+    global_bytes_down += length;
+    return pos;
+}
+
+
+void Channel::UpdateDIP(bin_t pos)
+{
+	if (!pos.is_none()) {
+		if (last_data_in_time_) {
+			tint dip = NOW - last_data_in_time_;
+			dip_avg_ = ( dip_avg_*3 + dip ) >> 2;
+		}
+		last_data_in_time_ = NOW;
+	}
+}
+
+
+void    Channel::OnAck (struct evbuffer *evb) {
+    bin_t ackd_pos = bin_fromUInt32(evbuffer_remove_32be(evb));
+    tint peer_time = evbuffer_remove_64be(evb); // FIXME 32
+    // FIXME FIXME: wrap around here
+    if (ackd_pos.is_none())
+        return; // likely, broken chunk/ insufficient hashes
+    if (file().size() && ackd_pos.base_offset()>=file().size_in_chunks()) {
+        char bin_name_buf[32];
+        eprintf("invalid ack: %s\n",ackd_pos.str(bin_name_buf));
+        return;
+    }
+    ack_in_.set(ackd_pos);
+
+    //fprintf(stderr,"OnAck: got bin %s is_complete %d\n", ackd_pos.str(), (int)ack_in_.is_complete_arno( file().ack_out().get_height() ));
+
+    int di = 0, ri = 0;
+    // find an entry for the send (data out) event
+    while (  di<data_out_.size() && ( data_out_[di]==tintbin() ||
+           !ackd_pos.contains(data_out_[di].bin) )  )
+        di++;
+    // FUTURE: delayed acks
+    // rule out retransmits
+    while (  ri<data_out_tmo_.size() && !ackd_pos.contains(data_out_tmo_[ri].bin) )
+        ri++;
+    char bin_name_buf[32];
+    dprintf("%s #%u %cack %s %lli\n",tintstr(),id_,
+            di==data_out_.size()?'?':'-',ackd_pos.str(bin_name_buf),peer_time);
+    if (di!=data_out_.size() && ri==data_out_tmo_.size()) { // not a retransmit
+            // round trip time calculations
+        tint rtt = NOW-data_out_[di].time;
+        rtt_avg_ = (rtt_avg_*7 + rtt) >> 3;
+        dev_avg_ = ( dev_avg_*3 + tintabs(rtt-rtt_avg_) ) >> 2;
+        assert(data_out_[di].time!=TINT_NEVER);
+            // one-way delay calculations
+        tint owd = peer_time - data_out_[di].time;
+        owd_cur_bin_ = 0;//(owd_cur_bin_+1) & 3;
+        owd_current_[owd_cur_bin_] = owd;
+        if ( owd_min_bin_start_+TINT_SEC*30 < NOW ) {
+            owd_min_bin_start_ = NOW;
+            owd_min_bin_ = (owd_min_bin_+1) & 3;
+            owd_min_bins_[owd_min_bin_] = TINT_NEVER;
+        }
+        if (owd_min_bins_[owd_min_bin_]>owd)
+            owd_min_bins_[owd_min_bin_] = owd;
+        dprintf("%s #%u sendctrl rtt %lli dev %lli based on %s\n",
+                tintstr(),id_,rtt_avg_,dev_avg_,data_out_[di].bin.str(bin_name_buf));
+        ack_rcvd_recent_++;
+        // early loss detection by packet reordering
+        for (int re=0; re<di-MAX_REORDERING; re++) {
+            if (data_out_[re]==tintbin())
+                continue;
+            ack_not_rcvd_recent_++;
+            data_out_tmo_.push_back(data_out_[re].bin);
+            dprintf("%s #%u Rdata %s\n",tintstr(),id_,data_out_.front().bin.str(bin_name_buf));
+            data_out_cap_ = bin_t::ALL;
+            data_out_[re] = tintbin();
+        }
+    }
+    if (di!=data_out_.size())
+        data_out_[di]=tintbin();
+    // clear zeroed items
+    while (!data_out_.empty() && ( data_out_.front()==tintbin() ||
+            ack_in_.is_filled(data_out_.front().bin) ) )
+        data_out_.pop_front();
+    assert(data_out_.empty() || data_out_.front().time!=TINT_NEVER);
+}
+
+
+void Channel::TimeoutDataOut ( ) {
+    // losses: timeouted packets
+    tint timeout = NOW - ack_timeout();
+    while (!data_out_.empty() &&
+        ( data_out_.front().time<timeout || data_out_.front()==tintbin() ) ) {
+        if (data_out_.front()!=tintbin() && ack_in_.is_empty(data_out_.front().bin)) {
+            ack_not_rcvd_recent_++;
+            data_out_cap_ = bin_t::ALL;
+            data_out_tmo_.push_back(data_out_.front().bin);
+            char bin_name_buf[32];
+            dprintf("%s #%u Tdata %s\n",tintstr(),id_,data_out_.front().bin.str(bin_name_buf));
+        }
+        data_out_.pop_front();
+    }
+    // clear retransmit queue of older items
+    while (!data_out_tmo_.empty() && data_out_tmo_.front().time<NOW-MAX_POSSIBLE_RTT)
+        data_out_tmo_.pop_front();
+}
+
+
+void Channel::OnHave (struct evbuffer *evb) {
+    bin_t ackd_pos = bin_fromUInt32(evbuffer_remove_32be(evb));
+    if (ackd_pos.is_none())
+        return; // wow, peer has hashes
+
+    // PPPLUG
+    if (ENABLE_VOD_PIECEPICKER) {
+		// Ric: check if we should set the size in the file transfer
+		if (transfer().availability().size() <= 0 && file().size() > 0)
+		{
+			transfer().availability().setSize(file().size_in_chunks());
+		}
+		// Ric: update the availability if needed
+		transfer().availability().set(id_, ack_in_, ackd_pos);
+    }
+
+    ack_in_.set(ackd_pos);
+    char bin_name_buf[32];
+    dprintf("%s #%u -have %s\n",tintstr(),id_,ackd_pos.str(bin_name_buf));
+
+    //fprintf(stderr,"OnHave: got bin %s is_complete %d\n", ackd_pos.str(), IsComplete() );
+
+}
+
+
+void    Channel::OnHint (struct evbuffer *evb) {
+    bin_t hint = bin_fromUInt32(evbuffer_remove_32be(evb));
+    // FIXME: wake up here
+    hint_in_.push_back(hint);
+    char bin_name_buf[32];
+    dprintf("%s #%u -hint %s\n",tintstr(),id_,hint.str(bin_name_buf));
+}
+
+
+void Channel::OnHandshake (struct evbuffer *evb) {
+
+	uint32_t pcid = evbuffer_remove_32be(evb);
+    dprintf("%s #%u -hs %x\n",tintstr(),id_,pcid);
+
+    if (is_established() && pcid == 0) {
+    	// Arno: received explicit close
+    	peer_channel_id_ = 0; // == established -> false
+    	Close();
+    	return;
+    }
+
+    peer_channel_id_ = pcid;
+    // self-connection check
+    if (!SELF_CONN_OK) {
+        uint32_t try_id = DecodeID(peer_channel_id_);
+        if (channel(try_id) && !channel(try_id)->peer_channel_id_) {
+            peer_channel_id_ = 0;
+            Close();
+            return; // this is a self-connection
+        }
+    }
+
+    // FUTURE: channel forking
+    if (is_established())
+        dprintf("%s #%u established %s\n", tintstr(), id_, peer().str());
+}
+
+
+void Channel::OnPex (struct evbuffer *evb) {
+    uint32_t ipv4 = evbuffer_remove_32be(evb);
+    uint16_t port = evbuffer_remove_16be(evb);
+    Address addr(ipv4,port);
+    dprintf("%s #%u -pex %s\n",tintstr(),id_,addr.str());
+    if (transfer().OnPexIn(addr))
+        useless_pex_count_ = 0;
+    else
+    {
+		dprintf("%s #%u already channel to %s\n", tintstr(),id_,addr.str());
+        useless_pex_count_++;
+    }
+    pex_request_outstanding_ = false;
+}
+
+
+//FRAGRAND
+void Channel::OnRandomize (struct evbuffer *evb) {
+    dprintf("%s #%u -rand\n",tintstr(),id_ );
+	// Payload is 4 random bytes
+    uint32_t r = evbuffer_remove_32be(evb);
+}
+
+
+void    Channel::AddPex (struct evbuffer *evb) {
+	// Gertjan fix: Reverse PEX
+    // PEX messages sent to facilitate NAT/FW puncturing get priority
+    if (!reverse_pex_out_.empty()) {
+        do {
+            tintbin pex_peer = reverse_pex_out_.front();
+            reverse_pex_out_.pop_front();
+            if (channels[(int) pex_peer.bin.toUInt()] == NULL)
+                continue;
+            Address a = channels[(int) pex_peer.bin.toUInt()]->peer();
+            // Arno, 2012-02-28: Don't send private addresses to non-private peers.
+            if (!a.is_private() || (a.is_private() && peer().is_private()))
+            {
+            	evbuffer_add_8(evb, SWIFT_PEX_ADD);
+            	evbuffer_add_32be(evb, a.ipv4());
+            	evbuffer_add_16be(evb, a.port());
+            	dprintf("%s #%u +pex (reverse) %s\n",tintstr(),id_,a.str());
+            }
+        } while (!reverse_pex_out_.empty() && (SWIFT_MAX_NONDATA_DGRAM_SIZE-evbuffer_get_length(evb)) >= 7);
+
+        // Arno: 2012-02-23: Don't think this is right. Bit of DoS thing,
+        // that you only get back the addr of people that got your addr.
+        // Disable for now.
+        //return;
+    }
+
+    if (!pex_requested_)
+        return;
+
+    // Arno, 2012-02-28: Don't send private addresses to non-private peers.
+    int chid = 0, tries=0;
+    Address a;
+    while (true)
+    {
+    	// Arno, 2011-10-03: Choosing Gertjan's RandomChannel over RevealChannel here.
+    	chid = transfer().RandomChannel(id_);
+    	if (chid==-1 || chid==id_ || tries > 5) {
+    		pex_requested_ = false;
+    		return;
+    	}
+    	a = channels[chid]->peer();
+    	if (!a.is_private() || (a.is_private() && peer().is_private()))
+    		break;
+    	tries++;
+    }
+
+    evbuffer_add_8(evb, SWIFT_PEX_ADD);
+    evbuffer_add_32be(evb, a.ipv4());
+    evbuffer_add_16be(evb, a.port());
+    dprintf("%s #%u +pex %s\n",tintstr(),id_,a.str());
+
+    pex_requested_ = false;
+    /* Ensure that we don't add the same id to the reverse_pex_out_ queue
+       more than once. */
+    for (tbqueue::iterator i = channels[chid]->reverse_pex_out_.begin();
+            i != channels[chid]->reverse_pex_out_.end(); i++)
+        if ((int) (i->bin.toUInt()) == id_)
+            return;
+
+    dprintf("%s #%u adding pex for channel %u at time %s\n", tintstr(), chid,
+        id_, tintstr(NOW + 2 * TINT_SEC));
+    // Arno, 2011-10-03: should really be a queue of (tint,channel id(= uint32_t)) pairs.
+    channels[chid]->reverse_pex_out_.push_back(tintbin(NOW + 2 * TINT_SEC, bin_t(id_)));
+    if (channels[chid]->send_control_ == KEEP_ALIVE_CONTROL &&
+            channels[chid]->next_send_time_ > NOW + 2 * TINT_SEC)
+        channels[chid]->Reschedule();
+}
+
+void Channel::OnPexReq(void) {
+    dprintf("%s #%u -pex req\n", tintstr(), id_);
+    if (NOW > MIN_PEX_REQUEST_INTERVAL + last_pex_request_time_)
+        pex_requested_ = true;
+}
+
+void Channel::AddPexReq(struct evbuffer *evb) {
+    // Rate limit the number of PEX requests
+    if (NOW < next_pex_request_time_)
+        return;
+
+    // If no answer has been received from a previous request, count it as useless
+    if (pex_request_outstanding_)
+        useless_pex_count_++;
+
+    pex_request_outstanding_ = false;
+
+    // Initiate at most SWIFT_MAX_CONNECTIONS connections
+    if (transfer().hs_in_.size() >= SWIFT_MAX_CONNECTIONS ||
+            // Check whether this channel has been providing useful peer information
+            useless_pex_count_ > 2)
+    {
+    	// Arno, 2012-02-23: Fix: Code doesn't recover from useless_pex_count_ > 2,
+    	// let's just try again in 30s
+		useless_pex_count_ = 0;
+		next_pex_request_time_ = NOW + 30 * TINT_SEC;
+
+        return;
+    }
+
+    dprintf("%s #%u +pex req\n", tintstr(), id_);
+    evbuffer_add_8(evb, SWIFT_PEX_REQ);
+    /* Add a little more than the minimum interval, such that the other party is
+       less likely to drop it due to too high rate */
+    next_pex_request_time_ = NOW + MIN_PEX_REQUEST_INTERVAL * 1.1;
+    pex_request_outstanding_ = true;
+}
+
+
+
+/*
+ * Channel class methods
+ */
+
+void Channel::LibeventReceiveCallback(evutil_socket_t fd, short event, void *arg) {
+	// Called by libevent when a datagram is received on the socket
+    Time();
+    RecvDatagram(fd);
+    event_add(&evrecv, NULL);
+}
+
+void    Channel::RecvDatagram (evutil_socket_t socket) {
+    struct evbuffer *evb = evbuffer_new();
+    Address addr;
+    RecvFrom(socket, addr, evb);
+    size_t evboriglen = evbuffer_get_length(evb);
+#define return_log(...) { fprintf(stderr,__VA_ARGS__); evbuffer_free(evb); return; }
+    if (evbuffer_get_length(evb)<4)
+        return_log("socket layer weird: datagram shorter than 4 bytes from %s (prob ICMP unreach)\n",addr.str());
+    uint32_t mych = evbuffer_remove_32be(evb);
+    Sha1Hash hash;
+    Channel* channel = NULL;
+    if (mych==0) { // peer initiates handshake
+        if (evbuffer_get_length(evb)<1+4+1+4+Sha1Hash::SIZE)
+            return_log ("%s #0 incorrect size %i initial handshake packet %s\n",
+                        tintstr(),(int)evbuffer_get_length(evb),addr.str());
+        uint8_t hashid = evbuffer_remove_8(evb);
+        if (hashid!=SWIFT_HASH)
+            return_log ("%s #0 no hash in the initial handshake %s\n",
+                        tintstr(),addr.str());
+        bin_t pos = bin_fromUInt32(evbuffer_remove_32be(evb));
+        if (!pos.is_all())
+            return_log ("%s #0 that is not the root hash %s\n",tintstr(),addr.str());
+        hash = evbuffer_remove_hash(evb);
+        FileTransfer* ft = FileTransfer::Find(hash);
+        if (!ft)
+            return_log ("%s #0 hash %s unknown, requested by %s\n",tintstr(),hash.hex().c_str(),addr.str());
+        dprintf("%s #0 -hash ALL %s\n",tintstr(),hash.hex().c_str());
+
+        // Arno, 2012-02-27: Check for duplicate channel
+        Channel* existchannel = ft->FindChannel(addr,NULL);
+        if (existchannel)
+        {
+			// Arno: 2011-10-13: Ignore if established, otherwise consider
+			// it a concurrent connection attempt.
+			if (existchannel->is_established()) {
+				// ARNOTODO: Read complete handshake here so we know whether
+				// attempt is to new channel or to existing. Currently read
+				// in OnHandshake()
+				//
+				return_log("%s #0 have a channel already to %s\n",tintstr(),addr.str());
+			} else {
+				channel = existchannel;
+				//fprintf(stderr,"Channel::RecvDatagram: HANDSHAKE: reuse channel %s\n", channel->peer_.str() );
+			}
+        }
+        if (channel == NULL) {
+        	//fprintf(stderr,"Channel::RecvDatagram: HANDSHAKE: create new channel %s\n", addr.str() );
+        	channel = new Channel(ft, socket, addr);
+        }
+        //fprintf(stderr,"CHANNEL INCOMING DEF hass %s is id %d\n",hash.hex().c_str(),channel->id());
+
+    } else { // peer responds to my handshake (and other messages)
+        mych = DecodeID(mych);
+        if (mych>=channels.size())
+            return_log("%s invalid channel #%u, %s\n",tintstr(),mych,addr.str());
+        channel = channels[mych];
+        if (!channel)
+            return_log ("%s #%u is already closed\n",tintstr(),mych);
+		if (channel->IsDiffSenderOrDuplicate(addr,mych)) {
+			channel->Schedule4Close();
+			return;
+		}
+        channel->own_id_mentioned_ = true;
+    }
+    channel->raw_bytes_down_ += evboriglen;
+    //dprintf("recvd %i bytes for %i\n",data.size(),channel->id);
+    bool wasestablished = channel->is_established();
+
+    dprintf("%s #%u peer %s recv_peer %s addr %s\n", tintstr(),mych, channel->peer().str(), channel->recv_peer().str(), addr.str() );
+
+    channel->Recv(evb);
+
+    evbuffer_free(evb);
+    //SAFECLOSE
+    if (wasestablished && !channel->is_established()) {
+    	// Arno, 2012-01-26: Received an explict close, clean up channel, safely.
+    	channel->Schedule4Close();
+    }
+}
+
+
+
+/*
+ * Channel instance methods
+ */
+
+void Channel::CloseChannelByAddress(const Address &addr)
+{
+	// fprintf(stderr,"CloseChannelByAddress: address is %s\n", addr.str() );
+    std::vector<Channel *>::iterator iter;
+    for (iter = channels.begin(); iter != channels.end(); iter++)
+    {
+		Channel *c = *iter;
+		if (c != NULL && c->peer_ == addr)
+		{
+			// ARNOSMPTODO: will do another send attempt before not being
+			// Rescheduled.
+			c->peer_channel_id_ = 0; // established->false, do no more sending
+			c->Schedule4Close();
+			break;
+		}
+    }
+}
+
+
+void Channel::Close () {
+
+	this->SwitchSendControl(CLOSE_CONTROL);
+
+    if (is_established())
+    	this->Send(); // Arno: send explicit close
+
+    if (ENABLE_VOD_PIECEPICKER) {
+		// Ric: remove it's binmap from the availability
+		transfer().availability().remove(id_, ack_in_);
+    }
+
+    // SAFECLOSE
+    // Arno: ensure LibeventSendCallback is no longer called with ptr to this Channel
+    ClearEvents();
+}
+
+
+void Channel::Reschedule () {
+
+	// Arno: CAREFUL: direct send depends on diff between next_send_time_ and
+	// NOW to be 0, so any calls to Time in between may put things off. Sigh.
+	Time();
+    next_send_time_ = NextSendTime();
+    if (next_send_time_!=TINT_NEVER) {
+
+    	assert(next_send_time_<NOW+TINT_MIN);
+        tint duein = next_send_time_-NOW;
+        if (duein <= 0) {
+        	// Arno, 2011-10-18: libevent's timer implementation appears to be
+        	// really slow, i.e., timers set for 100 usec from now get called
+        	// at least two times later :-( Hence, for sends after receives
+        	// perform them directly.
+        	dprintf("%s #%u requeue direct send\n",tintstr(),id_);
+        	LibeventSendCallback(-1,EV_TIMEOUT,this);
+        }
+        else {
+        	if (evsend_ptr_ != NULL) {
+        		struct timeval duetv = *tint2tv(duein);
+        		evtimer_add(evsend_ptr_,&duetv);
+        		dprintf("%s #%u requeue for %s in %lli\n",tintstr(),id_,tintstr(next_send_time_), duein);
+        	}
+        	else
+        		dprintf("%s #%u cannot requeue for %s, closed\n",tintstr(),id_,tintstr(next_send_time_));
+        }
+    } else {
+    	// SAFECLOSE
+        dprintf("%s #%u resched, will close\n",tintstr(),id_);
+		this->Schedule4Close();
+    }
+}
+
+
+/*
+ * Channel class methods
+ */
+void Channel::LibeventSendCallback(int fd, short event, void *arg) {
+
+	// Called by libevent when it is the requested send time.
+    Time();
+    Channel * sender = (Channel*) arg;
+    if (NOW<sender->next_send_time_-TINT_MSEC)
+        dprintf("%s #%u suspicious send %s<%s\n",tintstr(),
+                sender->id(),tintstr(NOW),tintstr(sender->next_send_time_));
+    if (sender->next_send_time_ != TINT_NEVER)
+    	sender->Send();
+}
+