pseudotcp.c 56.4 KB
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/*
 * This file is part of the Nice GLib ICE library.
 *
 * (C) 2010 Collabora Ltd.
 *  Contact: Youness Alaoui

 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Nice GLib ICE library.
 *
 * The Initial Developers of the Original Code are Collabora Ltd and Nokia
 * Corporation. All Rights Reserved.
 *
 * Contributors:
 *   Youness Alaoui, Collabora Ltd.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
 * case the provisions of LGPL are applicable instead of those above. If you
 * wish to allow use of your version of this file only under the terms of the
 * LGPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replace
 * them with the notice and other provisions required by the LGPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the LGPL.
 */

/* Reproducing license from libjingle for copied code */

/*
 * libjingle
 * Copyright 2004--2005, Google Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include <glib.h>
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#ifndef G_OS_WIN32
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#  include <arpa/inet.h>
#endif
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#include "pseudotcp.h"
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#include "agent-priv.h"
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G_DEFINE_TYPE (PseudoTcpSocket, pseudo_tcp_socket, G_TYPE_OBJECT);


//////////////////////////////////////////////////////////////////////
// Network Constants
//////////////////////////////////////////////////////////////////////

// Standard MTUs
const guint16 PACKET_MAXIMUMS[] = {
  65535,    // Theoretical maximum, Hyperchannel
  32000,    // Nothing
  17914,    // 16Mb IBM Token Ring
  8166,   // IEEE 802.4
  //4464,   // IEEE 802.5 (4Mb max)
  4352,   // FDDI
  //2048,   // Wideband Network
  2002,   // IEEE 802.5 (4Mb recommended)
  //1536,   // Expermental Ethernet Networks
  //1500,   // Ethernet, Point-to-Point (default)
  1492,   // IEEE 802.3
  1006,   // SLIP, ARPANET
  //576,    // X.25 Networks
  //544,    // DEC IP Portal
  //512,    // NETBIOS
  508,    // IEEE 802/Source-Rt Bridge, ARCNET
  296,    // Point-to-Point (low delay)
  //68,     // Official minimum
  0,      // End of list marker
};

#define MAX_PACKET 65535
// Note: we removed lowest level because packet overhead was larger!
#define MIN_PACKET 296

// (+ up to 40 bytes of options?)
#define IP_HEADER_SIZE 20
#define ICMP_HEADER_SIZE 8
#define UDP_HEADER_SIZE 8
// TODO: Make JINGLE_HEADER_SIZE transparent to this code?
// when relay framing is in use
#define JINGLE_HEADER_SIZE 64

//////////////////////////////////////////////////////////////////////
// Global Constants and Functions
//////////////////////////////////////////////////////////////////////
//
//    0                   1                   2                   3
//    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//  0 |                      Conversation Number                      |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//  4 |                        Sequence Number                        |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//  8 |                     Acknowledgment Number                     |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//    |               |   |U|A|P|R|S|F|                               |
// 12 |    Control    |   |R|C|S|S|Y|I|            Window             |
//    |               |   |G|K|H|T|N|N|                               |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 16 |                       Timestamp sending                       |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 20 |                      Timestamp receiving                      |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 24 |                             data                              |
//    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
//////////////////////////////////////////////////////////////////////

#define MAX_SEQ 0xFFFFFFFF
#define HEADER_SIZE 24

#define PACKET_OVERHEAD (HEADER_SIZE + UDP_HEADER_SIZE + \
      IP_HEADER_SIZE + JINGLE_HEADER_SIZE)

// MIN_RTO = 250 ms (RFC1122, Sec 4.2.3.1 "fractions of a second")
#define MIN_RTO      250
#define DEF_RTO     3000 /* 3 seconds (RFC1122, Sec 4.2.3.1) */
#define MAX_RTO    60000 /* 60 seconds */
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#define DEFAULT_ACK_DELAY    100 /* 100 milliseconds */
#define DEFAULT_NO_DELAY     FALSE
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#define DEFAULT_RCV_BUF_SIZE (60 * 1024)
#define DEFAULT_SND_BUF_SIZE (90 * 1024)

#define TCP_OPT_EOL       0  // End of list.
#define TCP_OPT_NOOP      1  // No-op.
#define TCP_OPT_MSS       2  // Maximum segment size.
#define TCP_OPT_WND_SCALE 3  // Window scale factor.


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/*
#define FLAG_FIN 0x01
#define FLAG_SYN 0x02
#define FLAG_ACK 0x10
*/

#define FLAG_CTL 0x02
#define FLAG_RST 0x04

#define CTL_CONNECT  0
//#define CTL_REDIRECT  1
#define CTL_EXTRA 255


#define CTRL_BOUND 0x80000000

// If there are no pending clocks, wake up every 4 seconds
#define DEFAULT_TIMEOUT 4000
// If the connection is closed, once per minute
#define CLOSED_TIMEOUT (60 * 1000)

//////////////////////////////////////////////////////////////////////
// Helper Functions
//////////////////////////////////////////////////////////////////////
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#ifndef G_OS_WIN32
#  define min(first, second) ((first) < (second) ? (first) : (second))
#  define max(first, second) ((first) > (second) ? (first) : (second))
#endif
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static guint32
bound(guint32 lower, guint32 middle, guint32 upper)
{
   return min (max (lower, middle), upper);
}

static guint32
get_current_time(void)
{
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  return g_get_monotonic_time () / 1000;
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}

static gboolean
time_is_between(guint32 later, guint32 middle, guint32 earlier)
{
  if (earlier <= later) {
    return ((earlier <= middle) && (middle <= later));
  } else {
    return !((later < middle) && (middle < earlier));
  }
}

static gint32
time_diff(guint32 later, guint32 earlier)
{
  guint32 LAST = 0xFFFFFFFF;
  guint32 HALF = 0x80000000;
  if (time_is_between(earlier + HALF, later, earlier)) {
    if (earlier <= later) {
      return (long)(later - earlier);
    } else {
      return (long)(later + (LAST - earlier) + 1);
    }
  } else {
    if (later <= earlier) {
      return -(long) (earlier - later);
    } else {
      return -(long)(earlier + (LAST - later) + 1);
    }
  }
}

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////////////////////////////////////////////////////////
// PseudoTcpFifo works exactly like FifoBuffer in libjingle
////////////////////////////////////////////////////////


typedef struct {
  guint8 *buffer;
  gsize buffer_length;
  gsize data_length;
  gsize read_position;
} PseudoTcpFifo;


static void
pseudo_tcp_fifo_init (PseudoTcpFifo *b, gsize size)
{
  b->buffer = g_slice_alloc (size);
  b->buffer_length = size;
}

static void
pseudo_tcp_fifo_clear (PseudoTcpFifo *b)
{
  if (b->buffer)
    g_slice_free1 (b->buffer_length, b->buffer);
  b->buffer = NULL;
  b->buffer_length = 0;
}

static gsize
pseudo_tcp_fifo_get_buffered (PseudoTcpFifo *b)
{
  return b->data_length;
}

static gboolean
pseudo_tcp_fifo_set_capacity (PseudoTcpFifo *b, gsize size)
{
  if (b->data_length > size)
    return FALSE;

  if (size != b->data_length) {
    guint8 *buffer = g_slice_alloc (size);
    gsize copy = b->data_length;
    gsize tail_copy = min (copy, b->buffer_length - b->read_position);

    memcpy (buffer, &b->buffer[b->read_position], tail_copy);
    memcpy (buffer + tail_copy, &b->buffer[0], copy - tail_copy);
    g_slice_free1 (b->buffer_length, b->buffer);
    b->buffer = buffer;
    b->buffer_length = size;
    b->read_position = 0;
  }

  return TRUE;
}

static void
pseudo_tcp_fifo_consume_read_data (PseudoTcpFifo *b, gsize size)
{
  g_assert (size <= b->data_length);

  b->read_position = (b->read_position + size) % b->buffer_length;
  b->data_length -= size;
}

static void
pseudo_tcp_fifo_consume_write_buffer (PseudoTcpFifo *b, gsize size)
{
  g_assert (size <= b->buffer_length - b->data_length);

  b->data_length += size;
}

static gsize
pseudo_tcp_fifo_get_write_remaining (PseudoTcpFifo *b)
{
  return b->buffer_length - b->data_length;
}

static gsize
pseudo_tcp_fifo_read_offset (PseudoTcpFifo *b, guint8 *buffer, gsize bytes,
    gsize offset)
{
  gsize available = b->data_length - offset;
  gsize read_position = (b->read_position + offset) % b->buffer_length;
  gsize copy = min (bytes, available);
  gsize tail_copy = min(copy, b->buffer_length - read_position);

  /* EOS */
  if (offset >= b->data_length)
    return 0;

  memcpy(buffer, &b->buffer[read_position], tail_copy);
  memcpy(buffer + tail_copy, &b->buffer[0], copy - tail_copy);

  return copy;
}

static gsize
pseudo_tcp_fifo_write_offset (PseudoTcpFifo *b, const guint8 *buffer,
    gsize bytes, gsize offset)
{
  gsize available = b->buffer_length - b->data_length - offset;
  gsize write_position = (b->read_position + b->data_length + offset)
      % b->buffer_length;
  gsize copy = min (bytes, available);
  gsize tail_copy = min(copy, b->buffer_length - write_position);

  if (b->data_length + offset >= b->buffer_length) {
    return 0;
  }

  memcpy(&b->buffer[write_position], buffer, tail_copy);
  memcpy(&b->buffer[0], buffer + tail_copy, copy - tail_copy);

  return copy;
}

static gsize
pseudo_tcp_fifo_read (PseudoTcpFifo *b, guint8 *buffer, gsize bytes)
{
  gsize copy;

  copy = pseudo_tcp_fifo_read_offset (b, buffer, bytes, 0);

  b->read_position = (b->read_position + copy) % b->buffer_length;
  b->data_length -= copy;

  return copy;
}

static gsize
pseudo_tcp_fifo_write (PseudoTcpFifo *b, const guint8 *buffer, gsize bytes)
{
  gsize copy;

  copy = pseudo_tcp_fifo_write_offset (b, buffer, bytes, 0);
  b->data_length += copy;

  return copy;
}


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//////////////////////////////////////////////////////////////////////
// PseudoTcp
//////////////////////////////////////////////////////////////////////

typedef enum {
  SD_NONE,
  SD_GRACEFUL,
  SD_FORCEFUL
} Shutdown;

typedef enum {
  sfNone,
  sfDelayedAck,
  sfImmediateAck
} SendFlags;

typedef struct {
  guint32 conv, seq, ack;
  guint8 flags;
  guint16 wnd;
  const gchar * data;
  guint32 len;
  guint32 tsval, tsecr;
} Segment;

typedef struct {
  guint32 seq, len;
  guint8 xmit;
  gboolean bCtrl;
} SSegment;

typedef struct {
  guint32 seq, len;
} RSegment;


struct _PseudoTcpSocketPrivate {
  PseudoTcpCallbacks callbacks;

  Shutdown shutdown;
  gint error;

  // TCB data
  PseudoTcpState state;
  guint32 conv;
  gboolean bReadEnable, bWriteEnable, bOutgoing;
  guint32 last_traffic;

  // Incoming data
  GList *rlist;
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  guint32 rbuf_len, rcv_nxt, rcv_wnd, lastrecv;
  guint8 rwnd_scale; // Window scale factor
  PseudoTcpFifo rbuf;
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  // Outgoing data
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  GQueue slist;
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  GQueue unsent_slist;
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  guint32 sbuf_len, snd_nxt, snd_wnd, lastsend;
  guint32 snd_una;  /* oldest unacknowledged sequence number */
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  guint8 swnd_scale; // Window scale factor
  PseudoTcpFifo sbuf;

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  // Maximum segment size, estimated protocol level, largest segment sent
  guint32 mss, msslevel, largest, mtu_advise;
  // Retransmit timer
  guint32 rto_base;

  // Timestamp tracking
  guint32 ts_recent, ts_lastack;

  // Round-trip calculation
  guint32 rx_rttvar, rx_srtt, rx_rto;

  // Congestion avoidance, Fast retransmit/recovery, Delayed ACKs
  guint32 ssthresh, cwnd;
  guint8 dup_acks;
  guint32 recover;
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  guint32 t_ack;  /* time a delayed ack was scheduled; 0 if no acks scheduled */
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  gboolean use_nagling;
  guint32 ack_delay;
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  // This is used by unit tests to test backward compatibility of
  // PseudoTcp implementations that don't support window scaling.
  gboolean support_wnd_scale;
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};

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#define LARGER(a,b) (((a) - (b) - 1) < (G_MAXUINT32 >> 1))
#define LARGER_OR_EQUAL(a,b) (((a) - (b)) < (G_MAXUINT32 >> 1))
#define SMALLER(a,b) LARGER ((b),(a))
#define SMALLER_OR_EQUAL(a,b) LARGER_OR_EQUAL ((b),(a))
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/* properties */
enum
{
  PROP_CONVERSATION = 1,
  PROP_CALLBACKS,
  PROP_STATE,
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  PROP_ACK_DELAY,
  PROP_NO_DELAY,
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  PROP_RCV_BUF,
  PROP_SND_BUF,
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  LAST_PROPERTY
};


static void pseudo_tcp_socket_get_property (GObject *object, guint property_id,
    GValue *value,  GParamSpec *pspec);
static void pseudo_tcp_socket_set_property (GObject *object, guint property_id,
    const GValue *value, GParamSpec *pspec);
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static void pseudo_tcp_socket_finalize (GObject *object);
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static void queue_connect_message (PseudoTcpSocket *self);
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static guint32 queue(PseudoTcpSocket *self, const gchar * data,
    guint32 len, gboolean bCtrl);
static PseudoTcpWriteResult packet(PseudoTcpSocket *self, guint32 seq,
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    guint8 flags, guint32 offset, guint32 len, guint32 now);
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static gboolean parse (PseudoTcpSocket *self,
    const guint8 *_header_buf, gsize header_buf_len,
    const guint8 *data_buf, gsize data_buf_len);
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static gboolean process(PseudoTcpSocket *self, Segment *seg);
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static gboolean transmit(PseudoTcpSocket *self, SSegment *sseg, guint32 now);
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static void attempt_send(PseudoTcpSocket *self, SendFlags sflags);
static void closedown(PseudoTcpSocket *self, guint32 err);
static void adjustMTU(PseudoTcpSocket *self);
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static void parse_options (PseudoTcpSocket *self, const guint8 *data,
    guint32 len);
static void resize_send_buffer (PseudoTcpSocket *self, guint32 new_size);
static void resize_receive_buffer (PseudoTcpSocket *self, guint32 new_size);
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static void set_state (PseudoTcpSocket *self, PseudoTcpState new_state);
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// The following logging is for detailed (packet-level) pseudotcp analysis only.
static PseudoTcpDebugLevel debug_level = PSEUDO_TCP_DEBUG_NONE;

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#define DEBUG(level, fmt, ...)                                          \
  if (debug_level >= level)                                             \
    g_log (level == PSEUDO_TCP_DEBUG_NORMAL ? "libnice-pseudotcp" : "libnice-pseudotcp-verbose", G_LOG_LEVEL_DEBUG, "PseudoTcpSocket %p: " fmt, \
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        self, ## __VA_ARGS__)
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void
pseudo_tcp_set_debug_level (PseudoTcpDebugLevel level)
{
  debug_level = level;
}
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static void
pseudo_tcp_socket_class_init (PseudoTcpSocketClass *cls)
{
  GObjectClass *object_class = G_OBJECT_CLASS (cls);

  object_class->get_property = pseudo_tcp_socket_get_property;
  object_class->set_property = pseudo_tcp_socket_set_property;
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  object_class->finalize = pseudo_tcp_socket_finalize;
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  g_object_class_install_property (object_class, PROP_CONVERSATION,
      g_param_spec_uint ("conversation", "TCP Conversation ID",
          "The TCP Conversation ID",
          0, G_MAXUINT32, 0,
          G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (object_class, PROP_CALLBACKS,
      g_param_spec_pointer ("callbacks", "PseudoTcp socket callbacks",
          "Structure with the callbacks to call when PseudoTcp events happen",
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (object_class, PROP_STATE,
      g_param_spec_uint ("state", "PseudoTcp State",
          "The current state (enum PseudoTcpState) of the PseudoTcp socket",
          TCP_LISTEN, TCP_CLOSED, TCP_LISTEN,
          G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

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  g_object_class_install_property (object_class, PROP_ACK_DELAY,
      g_param_spec_uint ("ack-delay", "ACK Delay",
          "Delayed ACK timeout (in milliseconds)",
          0, G_MAXUINT, DEFAULT_ACK_DELAY,
          G_PARAM_READWRITE| G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (object_class, PROP_NO_DELAY,
      g_param_spec_boolean ("no-delay", "No Delay",
          "Disable the Nagle algorithm (like the TCP_NODELAY option)",
          DEFAULT_NO_DELAY,
          G_PARAM_READWRITE| G_PARAM_STATIC_STRINGS));
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  g_object_class_install_property (object_class, PROP_RCV_BUF,
      g_param_spec_uint ("rcv-buf", "Receive Buffer",
          "Receive Buffer size",
          1, G_MAXUINT, DEFAULT_RCV_BUF_SIZE,
          G_PARAM_READWRITE| G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (object_class, PROP_SND_BUF,
      g_param_spec_uint ("snd-buf", "Send Buffer",
          "Send Buffer size",
          1, G_MAXUINT, DEFAULT_SND_BUF_SIZE,
          G_PARAM_READWRITE| G_PARAM_STATIC_STRINGS));
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}


static void
pseudo_tcp_socket_get_property (GObject *object,
                                  guint property_id,
                                  GValue *value,
                                  GParamSpec *pspec)
{
  PseudoTcpSocket *self = PSEUDO_TCP_SOCKET (object);

  switch (property_id) {
    case PROP_CONVERSATION:
      g_value_set_uint (value, self->priv->conv);
      break;
    case PROP_CALLBACKS:
      g_value_set_pointer (value, (gpointer) &self->priv->callbacks);
      break;
    case PROP_STATE:
      g_value_set_uint (value, self->priv->state);
      break;
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    case PROP_ACK_DELAY:
      g_value_set_uint (value, self->priv->ack_delay);
      break;
    case PROP_NO_DELAY:
      g_value_set_boolean (value, !self->priv->use_nagling);
      break;
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    case PROP_RCV_BUF:
      g_value_set_uint (value, self->priv->rbuf_len);
      break;
    case PROP_SND_BUF:
      g_value_set_uint (value, self->priv->sbuf_len);
      break;
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    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
  }
}

static void
pseudo_tcp_socket_set_property (GObject *object,
                                  guint property_id,
                                  const GValue *value,
                                  GParamSpec *pspec)
{
  PseudoTcpSocket *self = PSEUDO_TCP_SOCKET (object);

  switch (property_id) {
    case PROP_CONVERSATION:
      self->priv->conv = g_value_get_uint (value);
      break;
    case PROP_CALLBACKS:
      {
        PseudoTcpCallbacks *c = g_value_get_pointer (value);
        self->priv->callbacks = *c;
      }
      break;
637
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639
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641
642
    case PROP_ACK_DELAY:
      self->priv->ack_delay = g_value_get_uint (value);
      break;
    case PROP_NO_DELAY:
      self->priv->use_nagling = !g_value_get_boolean (value);
      break;
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649
650
    case PROP_RCV_BUF:
      g_return_if_fail (self->priv->state == TCP_LISTEN);
      resize_receive_buffer (self, g_value_get_uint (value));
      break;
    case PROP_SND_BUF:
      g_return_if_fail (self->priv->state == TCP_LISTEN);
      resize_send_buffer (self, g_value_get_uint (value));
      break;
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    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
  }
}

static void
658
pseudo_tcp_socket_finalize (GObject *object)
659
660
661
{
  PseudoTcpSocket *self = PSEUDO_TCP_SOCKET (object);
  PseudoTcpSocketPrivate *priv = self->priv;
662
  GList *i;
663
  SSegment *sseg;
664
665
666
667

  if (priv == NULL)
    return;

668
  while ((sseg = g_queue_pop_head (&priv->slist)))
669
    g_slice_free (SSegment, sseg);
670
  g_queue_clear (&priv->unsent_slist);
671
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  for (i = priv->rlist; i; i = i->next) {
    RSegment *rseg = i->data;
    g_slice_free (RSegment, rseg);
  }
  g_list_free (priv->rlist);
  priv->rlist = NULL;
677

678
679
680
  pseudo_tcp_fifo_clear (&priv->rbuf);
  pseudo_tcp_fifo_clear (&priv->sbuf);

681
682
683
  g_free (priv);
  self->priv = NULL;

684
685
  if (G_OBJECT_CLASS (pseudo_tcp_socket_parent_class)->finalize)
    G_OBJECT_CLASS (pseudo_tcp_socket_parent_class)->finalize (object);
686
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702
}


static void
pseudo_tcp_socket_init (PseudoTcpSocket *obj)
{
  /* Use g_new0, and do not use g_object_set_private because the size of
   * our private data is too big (150KB+) and the g_slice_allow cannot allocate
   * it. So we handle the private ourselves */
  PseudoTcpSocketPrivate *priv = g_new0 (PseudoTcpSocketPrivate, 1);
  guint32 now = get_current_time();

  obj->priv = priv;

  priv->shutdown = SD_NONE;
  priv->error = 0;

703
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705
706
707
  priv->rbuf_len = DEFAULT_RCV_BUF_SIZE;
  pseudo_tcp_fifo_init (&priv->rbuf, priv->rbuf_len);
  priv->sbuf_len = DEFAULT_SND_BUF_SIZE;
  pseudo_tcp_fifo_init (&priv->sbuf, priv->sbuf_len);

708
709
  priv->state = TCP_LISTEN;
  priv->conv = 0;
710
  g_queue_init (&priv->slist);
711
  g_queue_init (&priv->unsent_slist);
712
713
714
  priv->rcv_wnd = priv->rbuf_len;
  priv->rwnd_scale = priv->swnd_scale = 0;
  priv->snd_nxt = 0;
715
  priv->snd_wnd = 1;
716
  priv->snd_una = priv->rcv_nxt = 0;
717
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719
720
721
722
723
724
725
726
727
728
  priv->bReadEnable = TRUE;
  priv->bWriteEnable = FALSE;
  priv->t_ack = 0;

  priv->msslevel = 0;
  priv->largest = 0;
  priv->mss = MIN_PACKET - PACKET_OVERHEAD;
  priv->mtu_advise = MAX_PACKET;

  priv->rto_base = 0;

  priv->cwnd = 2 * priv->mss;
729
  priv->ssthresh = priv->rbuf_len;
730
731
732
733
734
735
736
737
738
739
  priv->lastrecv = priv->lastsend = priv->last_traffic = now;
  priv->bOutgoing = FALSE;

  priv->dup_acks = 0;
  priv->recover = 0;

  priv->ts_recent = priv->ts_lastack = 0;

  priv->rx_rto = DEF_RTO;
  priv->rx_srtt = priv->rx_rttvar = 0;
740
741
742

  priv->ack_delay = DEFAULT_ACK_DELAY;
  priv->use_nagling = !DEFAULT_NO_DELAY;
743
744

  priv->support_wnd_scale = TRUE;
745
746
}

747
748
749
750
751
752
753
754
755
756
PseudoTcpSocket *pseudo_tcp_socket_new (guint32 conversation,
    PseudoTcpCallbacks *callbacks)
{

  return g_object_new (PSEUDO_TCP_SOCKET_TYPE,
      "conversation", conversation,
      "callbacks", callbacks,
      NULL);
}

757
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759
760
761
762
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764
765
766
767
768
769
770
771
772
773
774
775
776
static void
queue_connect_message (PseudoTcpSocket *self)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  guint8 buf[4];
  gsize size = 1;

  buf[0] = CTL_CONNECT;
  if (priv->support_wnd_scale) {
    buf[1] = TCP_OPT_WND_SCALE;
    buf[2] = 1;
    buf[3] = priv->rwnd_scale;
    size = 4;
  }

  priv->snd_wnd = size;

  queue(self, (char*) buf, size, TRUE);
}

777
gboolean
778
779
780
781
782
783
pseudo_tcp_socket_connect(PseudoTcpSocket *self)
{
  PseudoTcpSocketPrivate *priv = self->priv;

  if (priv->state != TCP_LISTEN) {
    priv->error = EINVAL;
784
    return FALSE;
785
786
  }

787
  set_state (self, TCP_SYN_SENT);
788

789
  queue_connect_message (self);
790
791
  attempt_send(self, sfNone);

792
  return TRUE;
793
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795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
}

void
pseudo_tcp_socket_notify_mtu(PseudoTcpSocket *self, guint16 mtu)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  priv->mtu_advise = mtu;
  if (priv->state == TCP_ESTABLISHED) {
    adjustMTU(self);
  }
}

void
pseudo_tcp_socket_notify_clock(PseudoTcpSocket *self)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  guint32 now = get_current_time ();

  if (priv->state == TCP_CLOSED)
    return;

  // Check if it's time to retransmit a segment
  if (priv->rto_base &&
      (time_diff(priv->rto_base + priv->rx_rto, now) <= 0)) {
817
    if (g_queue_get_length (&priv->slist) == 0) {
818
819
820
821
822
823
824
      g_assert_not_reached ();
    } else {
      // Note: (priv->slist.front().xmit == 0)) {
      // retransmit segments
      guint32 nInFlight;
      guint32 rto_limit;

825
826
827
828
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "timeout retransmit (rto: %d) "
          "(rto_base: %d) (now: %d) (dup_acks: %d)",
          priv->rx_rto, priv->rto_base, now, (guint) priv->dup_acks);

829
      if (!transmit(self, g_queue_peek_head (&priv->slist), now)) {
830
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834
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837
838
839
840
841
842
843
844
845
846
847
848
849
850
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852
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854
        closedown(self, ECONNABORTED);
        return;
      }

      nInFlight = priv->snd_nxt - priv->snd_una;
      priv->ssthresh = max(nInFlight / 2, 2 * priv->mss);
      //LOG(LS_INFO) << "priv->ssthresh: " << priv->ssthresh << "  nInFlight: " << nInFlight << "  priv->mss: " << priv->mss;
      priv->cwnd = priv->mss;

      // Back off retransmit timer.  Note: the limit is lower when connecting.
      rto_limit = (priv->state < TCP_ESTABLISHED) ? DEF_RTO : MAX_RTO;
      priv->rx_rto = min(rto_limit, priv->rx_rto * 2);
      priv->rto_base = now;
    }
  }

  // Check if it's time to probe closed windows
  if ((priv->snd_wnd == 0)
        && (time_diff(priv->lastsend + priv->rx_rto, now) <= 0)) {
    if (time_diff(now, priv->lastrecv) >= 15000) {
      closedown(self, ECONNABORTED);
      return;
    }

    // probe the window
855
    packet(self, priv->snd_nxt - 1, 0, 0, 0, now);
856
857
858
859
860
861
862
    priv->lastsend = now;

    // back off retransmit timer
    priv->rx_rto = min(MAX_RTO, priv->rx_rto * 2);
  }

  // Check if it's time to send delayed acks
863
  if (priv->t_ack && (time_diff(priv->t_ack + priv->ack_delay, now) <= 0)) {
864
    packet(self, priv->snd_nxt, 0, 0, 0, now);
865
866
867
868
869
870
871
872
  }

}

gboolean
pseudo_tcp_socket_notify_packet(PseudoTcpSocket *self,
    const gchar * buffer, guint32 len)
{
873
874
  gboolean retval;

875
876
877
  if (len > MAX_PACKET) {
    //LOG_F(WARNING) << "packet too large";
    return FALSE;
878
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880
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883
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890
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899
900
  } else if (len < HEADER_SIZE) {
    //LOG_F(WARNING) << "packet too small";
    return FALSE;
  }

  /* Hold a reference to the PseudoTcpSocket during parsing, since it may be
   * closed from within a callback. */
  g_object_ref (self);
  retval = parse (self, (guint8 *) buffer, HEADER_SIZE,
      (guint8 *) buffer + HEADER_SIZE, len - HEADER_SIZE);
  g_object_unref (self);

  return retval;
}

/* Assume there are two buffers in the given #NiceInputMessage: a 24-byte one
 * containing the header, and a bigger one for the data. */
gboolean
pseudo_tcp_socket_notify_message (PseudoTcpSocket *self,
    NiceInputMessage *message)
{
  gboolean retval;

901
902
903
904
905
906
  g_assert_cmpuint (message->n_buffers, >, 0);

  if (message->n_buffers == 1)
    return pseudo_tcp_socket_notify_packet (self, message->buffers[0].buffer,
        message->buffers[0].size);

907
908
909
910
911
912
913
914
915
  g_assert_cmpuint (message->n_buffers, ==, 2);
  g_assert_cmpuint (message->buffers[0].size, ==, HEADER_SIZE);

  if (message->length > MAX_PACKET) {
    //LOG_F(WARNING) << "packet too large";
    return FALSE;
  } else if (message->length < HEADER_SIZE) {
    //LOG_F(WARNING) << "packet too small";
    return FALSE;
916
  }
917
918
919
920

  /* Hold a reference to the PseudoTcpSocket during parsing, since it may be
   * closed from within a callback. */
  g_object_ref (self);
921
922
  retval = parse (self, message->buffers[0].buffer, message->buffers[0].size,
      message->buffers[1].buffer, message->length - message->buffers[0].size);
923
924
925
  g_object_unref (self);

  return retval;
926
927
928
}

gboolean
929
pseudo_tcp_socket_get_next_clock(PseudoTcpSocket *self, guint64 *timeout)
930
931
932
{
  PseudoTcpSocketPrivate *priv = self->priv;
  guint32 now = get_current_time ();
933
  gsize snd_buffered;
934
935
936
937

  if (priv->shutdown == SD_FORCEFUL)
    return FALSE;

938
  snd_buffered = pseudo_tcp_fifo_get_buffered (&priv->sbuf);
939
940
  if ((priv->shutdown == SD_GRACEFUL)
      && ((priv->state != TCP_ESTABLISHED)
941
          || ((snd_buffered == 0) && (priv->t_ack == 0)))) {
942
943
944
    return FALSE;
  }

945
946
947
  if (*timeout == 0 || *timeout < now)
    *timeout = now + CLOSED_TIMEOUT;

948
  if (priv->state == TCP_CLOSED) {
949
    *timeout = min (*timeout, now + CLOSED_TIMEOUT);
950
951
952
    return TRUE;
  }

953
  *timeout = min (*timeout, now + DEFAULT_TIMEOUT);
954
955

  if (priv->t_ack) {
956
    *timeout = min(*timeout, priv->t_ack + priv->ack_delay);
957
958
  }
  if (priv->rto_base) {
959
    *timeout = min(*timeout, priv->rto_base + priv->rx_rto);
960
961
  }
  if (priv->snd_wnd == 0) {
962
    *timeout = min(*timeout, priv->lastsend + priv->rx_rto);
963
964
965
966
967
968
969
970
971
972
  }

  return TRUE;
}


gint
pseudo_tcp_socket_recv(PseudoTcpSocket *self, char * buffer, size_t len)
{
  PseudoTcpSocketPrivate *priv = self->priv;
973
  gsize bytesread;
974
  gsize available_space;
975
976
977
978
979
980

  if (priv->state != TCP_ESTABLISHED) {
    priv->error = ENOTCONN;
    return -1;
  }

981
982
983
  if (len == 0)
    return 0;

984
  bytesread = pseudo_tcp_fifo_read (&priv->rbuf, (guint8 *) buffer, len);
985
986

 // If there's no data in |m_rbuf|.
987
  if (bytesread == 0) {
988
989
990
991
992
    priv->bReadEnable = TRUE;
    priv->error = EWOULDBLOCK;
    return -1;
  }

993
  available_space = pseudo_tcp_fifo_get_write_remaining (&priv->rbuf);
994

995
996
  if (available_space - priv->rcv_wnd >=
      min (priv->rbuf_len / 2, priv->mss)) {
997
998
999
    // !?! Not sure about this was closed business
    gboolean bWasClosed = (priv->rcv_wnd == 0);

1000
    priv->rcv_wnd = available_space;
1001
1002
1003
1004
1005
1006

    if (bWasClosed) {
      attempt_send(self, sfImmediateAck);
    }
  }

1007
  return bytesread;
1008
1009
1010
1011
1012
1013
1014
}

gint
pseudo_tcp_socket_send(PseudoTcpSocket *self, const char * buffer, guint32 len)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  gint written;
1015
  gsize available_space;
1016
1017
1018
1019
1020
1021

  if (priv->state != TCP_ESTABLISHED) {
    priv->error = ENOTCONN;
    return -1;
  }

1022
1023
1024
  available_space = pseudo_tcp_fifo_get_write_remaining (&priv->sbuf);

  if (!available_space) {
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
    priv->bWriteEnable = TRUE;
    priv->error = EWOULDBLOCK;
    return -1;
  }

  written = queue(self, buffer, len, FALSE);
  attempt_send(self, sfNone);

  if (written > 0 && (guint32)written < len) {
    priv->bWriteEnable = TRUE;
  }

  return written;
}

void
pseudo_tcp_socket_close(PseudoTcpSocket *self, gboolean force)
{
  PseudoTcpSocketPrivate *priv = self->priv;
1044
1045
  DEBUG (PSEUDO_TCP_DEBUG_VERBOSE, "Closing socket %p : %s", self,
      force ? "forcefully" : "gracefully");
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
  priv->shutdown = force ? SD_FORCEFUL : SD_GRACEFUL;
}

int
pseudo_tcp_socket_get_error(PseudoTcpSocket *self)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  return priv->error;
}

//
// Internal Implementation
//

static guint32
queue(PseudoTcpSocket *self, const gchar * data, guint32 len, gboolean bCtrl)
{
  PseudoTcpSocketPrivate *priv = self->priv;
1064
  gsize available_space;
1065

1066
1067
  available_space = pseudo_tcp_fifo_get_write_remaining (&priv->sbuf);
  if (len > available_space) {
1068
    g_assert(!bCtrl);
1069
    len = available_space;
1070
1071
1072
1073
  }

  // We can concatenate data if the last segment is the same type
  // (control v. regular data), and has not been transmitted yet
1074
1075
1076
1077
  if (g_queue_get_length (&priv->slist) &&
      (((SSegment *)g_queue_peek_tail (&priv->slist))->bCtrl == bCtrl) &&
      (((SSegment *)g_queue_peek_tail (&priv->slist))->xmit == 0)) {
    ((SSegment *)g_queue_peek_tail (&priv->slist))->len += len;
1078
1079
  } else {
    SSegment *sseg = g_slice_new0 (SSegment);
1080
1081
1082
    gsize snd_buffered = pseudo_tcp_fifo_get_buffered (&priv->sbuf);

    sseg->seq = priv->snd_una + snd_buffered;
1083
1084
    sseg->len = len;
    sseg->bCtrl = bCtrl;
1085
    g_queue_push_tail (&priv->slist, sseg);
1086
    g_queue_push_tail (&priv->unsent_slist, sseg);
1087
1088
1089
  }

  //LOG(LS_INFO) << "PseudoTcp::queue - priv->slen = " << priv->slen;
1090
  return pseudo_tcp_fifo_write (&priv->sbuf, (guint8*) data, len);;
1091
1092
}

1093
1094
1095
1096
1097
1098
1099
1100
1101
// Creates a packet and submits it to the network. This method can either
// send payload or just an ACK packet.
//
// |seq| is the sequence number of this packet.
// |flags| is the flags for sending this packet.
// |offset| is the offset to read from |m_sbuf|.
// |len| is the number of bytes to read from |m_sbuf| as payload. If this
// value is 0 then this is an ACK packet, otherwise this packet has payload.

1102
1103
static PseudoTcpWriteResult
packet(PseudoTcpSocket *self, guint32 seq, guint8 flags,
1104
    guint32 offset, guint32 len, guint32 now)
1105
1106
{
  PseudoTcpSocketPrivate *priv = self->priv;
1107
1108
1109
1110
1111
  union {
    guint8 u8[MAX_PACKET];
    guint16 u16[MAX_PACKET / 2];
    guint32 u32[MAX_PACKET / 4];
  } buffer;
1112
1113
1114
1115
  PseudoTcpWriteResult wres = WR_SUCCESS;

  g_assert(HEADER_SIZE + len <= MAX_PACKET);

1116
1117
1118
1119
1120
  *buffer.u32 = htonl(priv->conv);
  *(buffer.u32 + 1) = htonl(seq);
  *(buffer.u32 + 2) = htonl(priv->rcv_nxt);
  buffer.u8[12] = 0;
  buffer.u8[13] = flags;
1121
  *(buffer.u16 + 7) = htons((guint16)(priv->rcv_wnd >> priv->rwnd_scale));
1122
1123

  // Timestamp computations
1124
1125
  *(buffer.u32 + 4) = htonl(now);
  *(buffer.u32 + 5) = htonl(priv->ts_recent);
1126
1127
  priv->ts_lastack = priv->rcv_nxt;

1128
1129
1130
1131
1132
1133
1134
  if (len) {
    gsize bytes_read;

    bytes_read = pseudo_tcp_fifo_read_offset (&priv->sbuf, buffer.u8 + HEADER_SIZE,
        len, offset);
    g_assert (bytes_read == len);
  }
1135

1136
1137
  DEBUG (PSEUDO_TCP_DEBUG_VERBOSE, "<-- <CONV=%d><FLG=%d><SEQ=%d:%d><ACK=%d>"
      "<WND=%d><TS=%d><TSR=%d><LEN=%d>",
1138
1139
1140
      priv->conv, (unsigned)flags, seq, seq + len, priv->rcv_nxt, priv->rcv_wnd,
      now % 10000, priv->ts_recent % 10000, len);

1141
  wres = priv->callbacks.WritePacket(self, (gchar *) buffer.u8, len + HEADER_SIZE,
1142
                                     priv->callbacks.user_data);
1143
  /* Note: When len is 0, this is an ACK packet.  We don't read the
1144
1145
1146
     return value for those, and thus we won't retry.  So go ahead and treat
     the packet as a success (basically simulate as if it were dropped),
     which will prevent our timers from being messed up. */
1147
  if ((wres != WR_SUCCESS) && (0 != len))
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
    return wres;

  priv->t_ack = 0;
  if (len > 0) {
    priv->lastsend = now;
  }
  priv->last_traffic = now;
  priv->bOutgoing = TRUE;

  return WR_SUCCESS;
}

static gboolean
1161
1162
parse (PseudoTcpSocket *self, const guint8 *_header_buf, gsize header_buf_len,
    const guint8 *data_buf, gsize data_buf_len)
1163
1164
1165
{
  Segment seg;

1166
1167
1168
1169
  union {
    const guint8 *u8;
    const guint16 *u16;
    const guint32 *u32;
1170
  } header_buf;
1171

1172
  header_buf.u8 = _header_buf;
1173

1174
  if (header_buf_len != 24)
1175
1176
    return FALSE;

1177
1178
1179
1180
1181
  seg.conv = ntohl(*header_buf.u32);
  seg.seq = ntohl(*(header_buf.u32 + 1));
  seg.ack = ntohl(*(header_buf.u32 + 2));
  seg.flags = header_buf.u8[13];
  seg.wnd = ntohs(*(header_buf.u16 + 7));
1182

1183
1184
  seg.tsval = ntohl(*(header_buf.u32 + 4));
  seg.tsecr = ntohl(*(header_buf.u32 + 5));
1185

1186
1187
  seg.data = (const gchar *) data_buf;
  seg.len = data_buf_len;
1188

1189
1190
  DEBUG (PSEUDO_TCP_DEBUG_VERBOSE, "--> <CONV=%d><FLG=%d><SEQ=%d:%d><ACK=%d>"
      "<WND=%d><TS=%d><TSR=%d><LEN=%d>",
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
      seg.conv, (unsigned)seg.flags, seg.seq, seg.seq + seg.len, seg.ack,
      seg.wnd, seg.tsval % 10000, seg.tsecr % 10000, seg.len);

  return process(self, &seg);
}


static gboolean
process(PseudoTcpSocket *self, Segment *seg)
{
  PseudoTcpSocketPrivate *priv = self->priv;
  guint32 now;
  SendFlags sflags = sfNone;
  gboolean bIgnoreData;
  gboolean bNewData;
  gboolean bConnect = FALSE;
1207
1208
1209
  gsize snd_buffered;
  gsize available_space;
  guint32 kIdealRefillSize;
1210
1211
1212
1213
1214
1215
1216

  /* If this is the wrong conversation, send a reset!?!
     (with the correct conversation?) */
  if (seg->conv != priv->conv) {
    //if ((seg->flags & FLAG_RST) == 0) {
    //  packet(sock, tcb, seg->ack, 0, FLAG_RST, 0, 0);
    //}
1217
    DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "wrong conversation");
1218
1219
1220
1221
1222
1223
1224
1225
1226
    return FALSE;
  }

  now = get_current_time();
  priv->last_traffic = priv->lastrecv = now;
  priv->bOutgoing = FALSE;

  if (priv->state == TCP_CLOSED) {
    // !?! send reset?
1227
    DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "closed");
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
    return FALSE;
  }

  // Check if this is a reset segment
  if (seg->flags & FLAG_RST) {
    closedown(self, ECONNRESET);
    return FALSE;
  }

  // Check for control data
  bConnect = FALSE;
  if (seg->flags & FLAG_CTL) {
    if (seg->len == 0) {
1241
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Missing control code");
1242
1243
1244
      return FALSE;
    } else if (seg->data[0] == CTL_CONNECT) {
      bConnect = TRUE;
1245
1246
1247

      parse_options (self, (guint8 *) &seg->data[1], seg->len - 1);

1248
      if (priv->state == TCP_LISTEN) {
1249
        set_state (self, TCP_SYN_RECEIVED);
1250
        queue_connect_message (self);
1251
      } else if (priv->state == TCP_SYN_SENT) {
1252
        set_state (self, TCP_ESTABLISHED);
1253
1254
1255
1256
1257
1258
        adjustMTU(self);
        if (priv->callbacks.PseudoTcpOpened)
          priv->callbacks.PseudoTcpOpened(self, priv->callbacks.user_data);

      }
    } else {
1259
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Unknown control code: %d", seg->data[0]);
1260
1261
1262
1263
1264
      return FALSE;
    }
  }

  // Update timestamp
1265
1266
  if (SMALLER_OR_EQUAL (seg->seq, priv->ts_lastack) &&
      SMALLER (priv->ts_lastack, seg->seq + seg->len)) {
1267
1268
1269
1270
    priv->ts_recent = seg->tsval;
  }

  // Check if this is a valuable ack
1271
1272
  if (LARGER(seg->ack, priv->snd_una) &&
      SMALLER_OR_EQUAL(seg->ack, priv->snd_nxt)) {
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
    guint32 nAcked;
    guint32 nFree;

    // Calculate round-trip time
    if (seg->tsecr) {
      long rtt = time_diff(now, seg->tsecr);
      if (rtt >= 0) {
        if (priv->rx_srtt == 0) {
          priv->rx_srtt = rtt;
          priv->rx_rttvar = rtt / 2;
        } else {
          priv->rx_rttvar = (3 * priv->rx_rttvar +
              abs((long)(rtt - priv->rx_srtt))) / 4;
          priv->rx_srtt = (7 * priv->rx_srtt + rtt) / 8;
        }
        priv->rx_rto = bound(MIN_RTO,
            priv->rx_srtt + max(1LU, 4 * priv->rx_rttvar), MAX_RTO);
1290
1291
1292

        DEBUG (PSEUDO_TCP_DEBUG_VERBOSE, "rtt: %ld   srtt: %d  rto: %d",
                rtt, priv->rx_srtt, priv->rx_rto);
1293
      } else {
1294
1295
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Invalid RTT: %ld", rtt);
        return FALSE;
1296
1297
1298
      }
    }

1299
    priv->snd_wnd = seg->wnd << priv->swnd_scale;
1300
1301
1302
1303
1304
1305

    nAcked = seg->ack - priv->snd_una;
    priv->snd_una = seg->ack;

    priv->rto_base = (priv->snd_una == priv->snd_nxt) ? 0 : now;

1306
    pseudo_tcp_fifo_consume_read_data (&priv->sbuf, nAcked);
1307
1308

    for (nFree = nAcked; nFree > 0; ) {
1309
1310
      SSegment *data;

1311
1312
      g_assert(g_queue_get_length (&priv->slist) != 0);
      data = (SSegment *) g_queue_peek_head (&priv->slist);
1313

1314
1315
      if (nFree < data->len) {
        data->len -= nFree;
1316
        data->seq += nFree;
1317
1318
1319
1320
1321
1322
        nFree = 0;
      } else {
        if (data->len > priv->largest) {
          priv->largest = data->len;
        }
        nFree -= data->len;
1323
1324
        g_slice_free (SSegment, data);
        g_queue_pop_head (&priv->slist);
1325
1326
1327
1328
      }
    }

    if (priv->dup_acks >= 3) {
1329
      if (LARGER_OR_EQUAL (priv->snd_una, priv->recover)) { // NewReno
1330
1331
1332
        guint32 nInFlight = priv->snd_nxt - priv->snd_una;
        // (Fast Retransmit)
        priv->cwnd = min(priv->ssthresh, nInFlight + priv->mss);
1333
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "exit recovery");
1334
1335
        priv->dup_acks = 0;
      } else {
1336
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "recovery retransmit");
1337
        if (!transmit(self, g_queue_peek_head (&priv->slist), now)) {
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
          closedown(self, ECONNABORTED);
          return FALSE;
        }
        priv->cwnd += priv->mss - min(nAcked, priv->cwnd);
      }
    } else {
      priv->dup_acks = 0;
      // Slow start, congestion avoidance
      if (priv->cwnd < priv->ssthresh) {
        priv->cwnd += priv->mss;
      } else {
        priv->cwnd += max(1LU, priv->mss * priv->mss / priv->cwnd);
      }
    }
  } else if (seg->ack == priv->snd_una) {
    /* !?! Note, tcp says don't do this... but otherwise how does a
       closed window become open? */
1355
    priv->snd_wnd = seg->wnd << priv->swnd_scale;
1356
1357
1358
1359
1360
1361
1362
1363
1364

    // Check duplicate acks
    if (seg->len > 0) {
      // it's a dup ack, but with a data payload, so don't modify priv->dup_acks
    } else if (priv->snd_una != priv->snd_nxt) {
      guint32 nInFlight;

      priv->dup_acks += 1;
      if (priv->dup_acks == 3) { // (Fast Retransmit)
1365
1366
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "enter recovery");
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "recovery retransmit");
1367
        if (!transmit(self, g_queue_peek_head (&priv->slist), now)) {
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
          closedown(self, ECONNABORTED);
          return FALSE;
        }
        priv->recover = priv->snd_nxt;
        nInFlight = priv->snd_nxt - priv->snd_una;
        priv->ssthresh = max(nInFlight / 2, 2 * priv->mss);
        //LOG(LS_INFO) << "priv->ssthresh: " << priv->ssthresh << "  nInFlight: " << nInFlight << "  priv->mss: " << priv->mss;
        priv->cwnd = priv->ssthresh + 3 * priv->mss;
      } else if (priv->dup_acks > 3) {
        priv->cwnd += priv->mss;
      }
    } else {
      priv->dup_acks = 0;
    }
  }

1384
1385
  // !?! A bit hacky
  if ((priv->state == TCP_SYN_RECEIVED) && !bConnect) {
1386
    set_state (self, TCP_ESTABLISHED);
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
    adjustMTU(self);
    if (priv->callbacks.PseudoTcpOpened)
      priv->callbacks.PseudoTcpOpened(self, priv->callbacks.user_data);
  }

  // If we make room in the send queue, notify the user
  // The goal it to make sure we always have at least enough data to fill the
  // window.  We'd like to notify the app when we are halfway to that point.
  kIdealRefillSize = (priv->sbuf_len + priv->rbuf_len) / 2;

  snd_buffered = pseudo_tcp_fifo_get_buffered (&priv->sbuf);
  if (priv->bWriteEnable && snd_buffered < kIdealRefillSize) {
    priv->bWriteEnable = FALSE;
    if (priv->callbacks.PseudoTcpWritable)
      priv->callbacks.PseudoTcpWritable(self, priv->callbacks.user_data);
  }

1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
  /* Conditions where acks must be sent:
   * 1) Segment is too old (they missed an ACK) (immediately)
   * 2) Segment is too new (we missed a segment) (immediately)
   * 3) Segment has data (so we need to ACK!) (delayed)
   * ... so the only time we don't need to ACK, is an empty segment
   * that points to rcv_nxt!
   */

  if (seg->seq != priv->rcv_nxt) {
    sflags = sfImmediateAck; // (Fast Recovery)
  } else if (seg->len != 0) {
1415
1416
1417
1418
1419
    if (priv->ack_delay == 0) {
      sflags = sfImmediateAck;
    } else {
      sflags = sfDelayedAck;
    }
1420
1421
1422
  }
  if (sflags == sfImmediateAck) {
    if (seg->seq > priv->rcv_nxt) {
1423
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "too new");
1424
    } else if (SMALLER_OR_EQUAL(seg->seq + seg->len, priv->rcv_nxt)) {
1425
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "too old");
1426
1427
1428
1429
    }
  }

  // Adjust the incoming segment to fit our receive buffer
1430
  if (SMALLER(seg->seq, priv->rcv_nxt)) {
1431
1432
1433
1434
1435
1436
1437
1438
1439
    guint32 nAdjust = priv->rcv_nxt - seg->seq;
    if (nAdjust < seg->len) {
      seg->seq += nAdjust;
      seg->data += nAdjust;
      seg->len -= nAdjust;
    } else {
      seg->len = 0;
    }
  }
1440
1441
1442
1443
1444

  available_space = pseudo_tcp_fifo_get_write_remaining (&priv->rbuf);

  if ((seg->seq + seg->len - priv->rcv_nxt) > available_space) {
    guint32 nAdjust = seg->seq + seg->len - priv->rcv_nxt - available_space;
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
    if (nAdjust < seg->len) {
      seg->len -= nAdjust;
    } else {
      seg->len = 0;
    }
  }

  bIgnoreData = (seg->flags & FLAG_CTL) || (priv->shutdown != SD_NONE);
  bNewData = FALSE;

  if (seg->len > 0) {
    if (bIgnoreData) {
      if (seg->seq == priv->rcv_nxt) {
        priv->rcv_nxt += seg->len;
      }
    } else {
      guint32 nOffset = seg->seq - priv->rcv_nxt;
1462
      gsize res;
1463

1464
1465
1466
      res = pseudo_tcp_fifo_write_offset (&priv->rbuf, (guint8 *) seg->data,
          seg->len, nOffset);
      g_assert (res == seg->len);
1467

1468
1469
1470
      if (seg->seq == priv->rcv_nxt) {
        GList *iter = NULL;

1471
        pseudo_tcp_fifo_consume_write_buffer (&priv->rbuf, seg->len);
1472
1473
1474
1475
1476
        priv->rcv_nxt += seg->len;
        priv->rcv_wnd -= seg->len;
        bNewData = TRUE;

        iter = priv->rlist;
1477
1478
        while (iter &&
            SMALLER_OR_EQUAL(((RSegment *)iter->data)->seq, priv->rcv_nxt)) {
1479
          RSegment *data = (RSegment *)(iter->data);
1480
          if (LARGER (data->seq + data->len, priv->rcv_nxt)) {
1481
1482
            guint32 nAdjust = (data->seq + data->len) - priv->rcv_nxt;
            sflags = sfImmediateAck; // (Fast Recovery)
1483
1484
            DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Recovered %d bytes (%d -> %d)",
                nAdjust, priv->rcv_nxt, priv->rcv_nxt + nAdjust);
1485
            pseudo_tcp_fifo_consume_write_buffer (&priv->rbuf, nAdjust);
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
            priv->rcv_nxt += nAdjust;
            priv->rcv_wnd -= nAdjust;
          }
          g_slice_free (RSegment, priv->rlist->data);
          priv->rlist = g_list_delete_link (priv->rlist, priv->rlist);
          iter = priv->rlist;
        }
      } else {
        GList *iter = NULL;
        RSegment *rseg = g_slice_new0 (RSegment);
1496
1497
1498

        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Saving %d bytes (%d -> %d)",
            seg->len, seg->seq, seg->seq + seg->len);
1499
1500
1501
        rseg->seq = seg->seq;
        rseg->len = seg->len;
        iter = priv->rlist;
1502
        while (iter && SMALLER (((RSegment*)iter->data)->seq, rseg->seq)) {
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
          iter = g_list_next (iter);
        }
        priv->rlist = g_list_insert_before(priv->rlist, iter, rseg);
      }
    }
  }

  attempt_send(self, sflags);

  // If we have new data, notify the user
  if (bNewData && priv->bReadEnable) {
1514
1515
1516
1517
    /* priv->bReadEnable = FALSE; — removed so that we’re always notified of
     * incoming pseudo-TCP data, rather than having to read the entire buffer
     * on each readable() callback before the next callback is enabled.
     * (When client-provided buffers are small, this is not possible.) */
1518
1519
1520
1521
1522
1523
1524
1525
    if (priv->callbacks.PseudoTcpReadable)
      priv->callbacks.PseudoTcpReadable(self, priv->callbacks.user_data);
  }

  return TRUE;
}

static gboolean
1526
transmit(PseudoTcpSocket *self, SSegment *segment, guint32 now)
1527
1528
1529
1530
1531
{
  PseudoTcpSocketPrivate *priv = self->priv;
  guint32 nTransmit = min(segment->len, priv->mss);

  if (segment->xmit >= ((priv->state == TCP_ESTABLISHED) ? 15 : 30)) {
1532
    DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "too many retransmits");
1533
1534
1535
1536
1537
1538
    return FALSE;
  }

  while (TRUE) {
    guint32 seq = segment->seq;
    guint8 flags = (segment->bCtrl ? FLAG_CTL : 0);
1539
1540
1541
1542
1543
1544
1545
    PseudoTcpWriteResult wres;

    /* The packet must not have already been acknowledged. */
    g_assert_cmpuint (segment->seq, >=, priv->snd_una);

    /* Write out the packet. */
    wres = packet(self, seq, flags,
1546
        segment->seq - priv->snd_una, nTransmit, now);
1547
1548
1549
1550
1551

    if (wres == WR_SUCCESS)
      break;

    if (wres == WR_FAIL) {
1552
      DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "packet failed");
1553
1554
1555
1556
1557
1558
1559
      return FALSE;
    }

    g_assert(wres == WR_TOO_LARGE);

    while (TRUE) {
      if (PACKET_MAXIMUMS[priv->msslevel + 1] == 0) {
1560
        DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "MTU too small");
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
        return FALSE;
      }
      /* !?! We need to break up all outstanding and pending packets
         and then retransmit!?! */

      priv->mss = PACKET_MAXIMUMS[++priv->msslevel] - PACKET_OVERHEAD;
      // I added this... haven't researched actual formula
      priv->cwnd = 2 * priv->mss;

      if (priv->mss < nTransmit) {
        nTransmit = priv->mss;
        break;
      }
    }
1575
    DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "Adjusting mss to %d bytes ", priv->mss);
1576
1577
1578
1579
1580
1581
1582
1583
1584
  }

  if (nTransmit < segment->len) {
    SSegment *subseg = g_slice_new0 (SSegment);
    subseg->seq = segment->seq + nTransmit;
    subseg->len = segment->len - nTransmit;
    subseg->bCtrl = segment->bCtrl;
    subseg->xmit = segment->xmit;

1585
    DEBUG (PSEUDO_TCP_DEBUG_NORMAL, "mss reduced to %d", priv->mss);
1586
1587