// user/upper level send, returns below zero for error
public int Send(byte[] bytes, int index, int length)
{
if (0 == bytes.Length)
{
return(-1);
}
if (length == 0)
{
return(-1);
}
var count = 0;
if (length < mss)
{
count = 1;
}
else
{
count = (int)(length + mss - 1) / (int)mss;
}
if (255 < count)
{
return(-2);
}
if (0 == count)
{
count = 1;
}
var offset = 0;
for (var i = 0; i < count; i++)
{
var size = 0;
if (length - offset > mss)
{
size = (int)mss;
}
else
{
size = length - offset;
}
var seg = new Segment(size);
Array.Copy(bytes, offset + index, seg.data, 0, size);
offset += size;
seg.frg = (UInt32)(count - i - 1);
snd_queue = KcpHelper.append(snd_queue, seg);
}
return(0);
}
private void parse_ack(UInt32 sn)
{
if (KcpHelper._itimediff(sn, snd_una) < 0 || KcpHelper._itimediff(sn, snd_nxt) >= 0)
{
return;
}
var index = 0;
foreach (var seg in snd_buf)
{
if (sn == seg.sn)
{
snd_buf = KcpHelper.append(KcpHelper.slice(snd_buf, 0, index), KcpHelper.slice(snd_buf, index + 1, snd_buf.Length));
break;
}
seg.fastack++;
index++;
}
}
// flush pending data
private void flush()
{
var current_ = current;
var buffer_ = buffer;
var change = 0;
var lost = 0;
if (0 == updated)
{
return;
}
var seg = new Segment(0);
seg.conv = conv;
seg.cmd = IKCP_CMD_ACK;
seg.wnd = (UInt32)wnd_unused();
seg.una = rcv_nxt;
// flush acknowledges
var count = acklist.Length / 2;
var offset = 0;
for (var i = 0; i < count; i++)
{
if (offset + IKCP_OVERHEAD > mtu)
{
output(buffer, offset);
//Array.Clear(buffer, 0, offset);
offset = 0;
}
ack_get(i, ref seg.sn, ref seg.ts);
offset += seg.encode(buffer, offset);
}
acklist = new UInt32[0];
// probe window size (if remote window size equals zero)
if (0 == rmt_wnd)
{
if (0 == probe_wait)
{
probe_wait = IKCP_PROBE_INIT;
ts_probe = current + probe_wait;
}
else
{
if (KcpHelper._itimediff(current, ts_probe) >= 0)
{
if (probe_wait < IKCP_PROBE_INIT)
{
probe_wait = IKCP_PROBE_INIT;
}
probe_wait += probe_wait / 2;
if (probe_wait > IKCP_PROBE_LIMIT)
{
probe_wait = IKCP_PROBE_LIMIT;
}
ts_probe = current + probe_wait;
probe |= IKCP_ASK_SEND;
}
}
}
else
{
ts_probe = 0;
probe_wait = 0;
}
// flush window probing commands
if ((probe & IKCP_ASK_SEND) != 0)
{
seg.cmd = IKCP_CMD_WASK;
if (offset + IKCP_OVERHEAD > (int)mtu)
{
output(buffer, offset);
//Array.Clear(buffer, 0, offset);
offset = 0;
}
offset += seg.encode(buffer, offset);
}
probe = 0;
// calculate window size
var cwnd_ = KcpHelper._imin_(snd_wnd, rmt_wnd);
if (0 == nocwnd)
{
cwnd_ = KcpHelper._imin_(cwnd, cwnd_);
}
count = 0;
for (var k = 0; k < snd_queue.Length; k++)
{
if (KcpHelper._itimediff(snd_nxt, snd_una + cwnd_) >= 0)
{
break;
}
var newseg = snd_queue[k];
newseg.conv = conv;
newseg.cmd = IKCP_CMD_PUSH;
newseg.wnd = seg.wnd;
newseg.ts = current_;
newseg.sn = snd_nxt;
newseg.una = rcv_nxt;
newseg.resendts = current_;
newseg.rto = rx_rto;
newseg.fastack = 0;
newseg.xmit = 0;
snd_buf = KcpHelper.append(snd_buf, newseg);
snd_nxt++;
count++;
}
if (0 < count)
{
this.snd_queue = KcpHelper.slice(this.snd_queue, count, this.snd_queue.Length);
}
// calculate resent
var resent = (UInt32)fastresend;
if (fastresend <= 0)
{
resent = 0xffffffff;
}
var rtomin = rx_rto >> 3;
if (nodelay != 0)
{
rtomin = 0;
}
// flush data segments
foreach (var segment in snd_buf)
{
var needsend = false;
var debug = KcpHelper._itimediff(current_, segment.resendts);
if (0 == segment.xmit)
{
needsend = true;
segment.xmit++;
segment.rto = rx_rto;
segment.resendts = current_ + segment.rto + rtomin;
}
else if (KcpHelper._itimediff(current_, segment.resendts) >= 0)
{
needsend = true;
segment.xmit++;
xmit++;
if (0 == nodelay)
{
segment.rto += rx_rto;
}
else
{
segment.rto += rx_rto / 2;
}
segment.resendts = current_ + segment.rto;
lost = 1;
}
else if (segment.fastack >= resent)
{
needsend = true;
segment.xmit++;
segment.fastack = 0;
segment.resendts = current_ + segment.rto;
change++;
}
if (needsend)
{
segment.ts = current_;
segment.wnd = seg.wnd;
segment.una = rcv_nxt;
var need = IKCP_OVERHEAD + segment.data.Length;
if (offset + need > mtu)
{
output(buffer, offset);
//Array.Clear(buffer, 0, offset);
offset = 0;
}
offset += segment.encode(buffer, offset);
if (segment.data.Length > 0)
{
Array.Copy(segment.data, 0, buffer, offset, segment.data.Length);
offset += segment.data.Length;
}
if (segment.xmit >= dead_link)
{
this.state = 0;
}
}
}
// flash remain segments
if (offset > 0)
{
output(buffer, offset);
//Array.Clear(buffer, 0, offset);
offset = 0;
}
// update ssthresh
if (change != 0)
{
var inflight = snd_nxt - snd_una;
ssthresh = inflight / 2;
if (ssthresh < IKCP_THRESH_MIN)
{
ssthresh = IKCP_THRESH_MIN;
}
cwnd = ssthresh + resent;
incr = cwnd * mss;
}
if (lost != 0)
{
ssthresh = cwnd / 2;
if (ssthresh < IKCP_THRESH_MIN)
{
ssthresh = IKCP_THRESH_MIN;
}
cwnd = 1;
incr = mss;
}
if (cwnd < 1)
{
cwnd = 1;
incr = mss;
}
}
private void parse_data(Segment newseg)
{
var sn = newseg.sn;
if (KcpHelper._itimediff(sn, rcv_nxt + rcv_wnd) >= 0 || KcpHelper._itimediff(sn, rcv_nxt) < 0)
{
return;
}
var n = rcv_buf.Length - 1;
var after_idx = -1;
var repeat = false;
for (var i = n; i >= 0; i--)
{
var seg = rcv_buf[i];
if (seg.sn == sn)
{
repeat = true;
break;
}
if (KcpHelper._itimediff(sn, seg.sn) > 0)
{
after_idx = i;
break;
}
}
if (!repeat)
{
if (after_idx == -1)
{
this.rcv_buf = KcpHelper.append(new Segment[1] {
newseg
}, this.rcv_buf);
}
else
{
this.rcv_buf = KcpHelper.append(KcpHelper.slice(this.rcv_buf, 0, after_idx + 1),
KcpHelper.append(new Segment[1] {
newseg
}, KcpHelper.slice(this.rcv_buf, after_idx + 1, this.rcv_buf.Length)));
}
}
// move available data from rcv_buf -> rcv_queue
var count = 0;
foreach (var seg in rcv_buf)
{
if (seg.sn == this.rcv_nxt && this.rcv_queue.Length < this.rcv_wnd)
{
this.rcv_queue = KcpHelper.append(this.rcv_queue, seg);
this.rcv_nxt++;
count++;
}
else
{
break;
}
}
if (0 < count)
{
this.rcv_buf = KcpHelper.slice(this.rcv_buf, count, this.rcv_buf.Length);
}
}
private void ack_push(UInt32 sn, UInt32 ts)
{
acklist = KcpHelper.append(acklist, new UInt32[2] {
sn, ts
});
}
// user/upper level recv: returns size, returns below zero for EAGAIN
public int Recv(byte[] buffer)
{
if (0 == rcv_queue.Length)
{
return(-1);
}
var peekSize = PeekSize();
if (0 > peekSize)
{
return(-2);
}
if (peekSize > buffer.Length)
{
return(-3);
}
var fast_recover = false;
if (rcv_queue.Length >= rcv_wnd)
{
fast_recover = true;
}
// merge fragment.
var count = 0;
var n = 0;
foreach (var seg in rcv_queue)
{
Array.Copy(seg.data, 0, buffer, n, seg.data.Length);
n += seg.data.Length;
count++;
if (0 == seg.frg)
{
break;
}
}
if (0 < count)
{
this.rcv_queue = KcpHelper.slice(this.rcv_queue, count, this.rcv_queue.Length);
}
// move available data from rcv_buf -> rcv_queue
count = 0;
foreach (var seg in rcv_buf)
{
if (seg.sn == this.rcv_nxt && this.rcv_queue.Length < this.rcv_wnd)
{
this.rcv_queue = KcpHelper.append(this.rcv_queue, seg);
this.rcv_nxt++;
count++;
}
else
{
break;
}
}
if (0 < count)
{
rcv_buf = KcpHelper.slice(rcv_buf, count, rcv_buf.Length);
}
// fast recover
if (rcv_queue.Length < rcv_wnd && fast_recover)
{
this.probe |= IKCP_ASK_TELL;
}
return(n);
}
